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    Alternative splicing promotes tumour aggressiveness and drug resistance in African American prostate cancer. Wang Bi-Dar,Ceniccola Kristin,Hwang SuJin,Andrawis Ramez,Horvath Anelia,Freedman Jennifer A,Olender Jacqueline,Knapp Stefan,Ching Travers,Garmire Lana,Patel Vyomesh,Garcia-Blanco Mariano A,Patierno Steven R,Lee Norman H Nature communications Clinical challenges exist in reducing prostate cancer (PCa) disparities. The RNA splicing landscape of PCa across racial populations has not been fully explored as a potential molecular mechanism contributing to race-related tumour aggressiveness. Here, we identify novel genome-wide, race-specific RNA splicing events as critical drivers of PCa aggressiveness and therapeutic resistance in African American (AA) men. AA-enriched splice variants of PIK3CD, FGFR3, TSC2 and RASGRP2 contribute to greater oncogenic potential compared with corresponding European American (EA)-expressing variants. Ectopic overexpression of the newly cloned AA-enriched variant, PIK3CD-S, in EA PCa cell lines enhances AKT/mTOR signalling and increases proliferative and invasive capacity in vitro and confers resistance to selective PI3Kδ inhibitor, CAL-101 (idelalisib), in mouse xenograft models. High PIK3CD-S expression in PCa specimens associates with poor survival. These results highlight the potential of RNA splice variants to serve as novel biomarkers and molecular targets for developmental therapeutics in aggressive PCa. 10.1038/ncomms15921
    PI3Kδ inhibitors in cancer: rationale and serendipity merge in the clinic. Fruman David A,Rommel Christian Cancer discovery UNLABELLED:Several phosphoinositide 3-kinase (PI3K) inhibitors are in the clinic and many more are in preclinical development. CAL-101, a selective inhibitor of the PI3Kδ isoform, has shown remarkable success in certain hematologic malignancies. Although PI3Kδ signaling plays a central role in lymphocyte biology, the degree of single-agent therapeutic activity of CAL-101 during early-phase development has been somewhat unexpected. CAL-101 works in part by blocking signals from the microenvironment that normally sustain leukemia and lymphoma cells in a protective niche. As PI3Ks enter the arena of molecular-targeted therapies, CAL-101 provides proof of principle that isoform-selective compounds can be effective in selected cancer types and patient populations. SIGNIFICANCE:A key question is whether compounds targeting a single PI3K catalytic isoform can provide meaningful single agent efficacy in cancer cells that express multiple isoforms. Clinical studies of the drug CAL-101 have provided a significant advance by showing that selective targeting of PI3Kδ achieves efficacy in chronic lymphocytic leukemia, in part through targeting the tumor microenvironment. 10.1158/2159-8290.CD-11-0249
    Phosphoinositide 3-kinase δ gene mutation predisposes to respiratory infection and airway damage. Angulo Ivan,Vadas Oscar,Garçon Fabien,Banham-Hall Edward,Plagnol Vincent,Leahy Timothy R,Baxendale Helen,Coulter Tanya,Curtis James,Wu Changxin,Blake-Palmer Katherine,Perisic Olga,Smyth Deborah,Maes Mailis,Fiddler Christine,Juss Jatinder,Cilliers Deirdre,Markelj Gašper,Chandra Anita,Farmer George,Kielkowska Anna,Clark Jonathan,Kracker Sven,Debré Marianne,Picard Capucine,Pellier Isabelle,Jabado Nada,Morris James A,Barcenas-Morales Gabriela,Fischer Alain,Stephens Len,Hawkins Phillip,Barrett Jeffrey C,Abinun Mario,Clatworthy Menna,Durandy Anne,Doffinger Rainer,Chilvers Edwin R,Cant Andrew J,Kumararatne Dinakantha,Okkenhaug Klaus,Williams Roger L,Condliffe Alison,Nejentsev Sergey Science (New York, N.Y.) Genetic mutations cause primary immunodeficiencies (PIDs) that predispose to infections. Here, we describe activated PI3K-δ syndrome (APDS), a PID associated with a dominant gain-of-function mutation in which lysine replaced glutamic acid at residue 1021 (E1021K) in the p110δ protein, the catalytic subunit of phosphoinositide 3-kinase δ (PI3Kδ), encoded by the PIK3CD gene. We found E1021K in 17 patients from seven unrelated families, but not among 3346 healthy subjects. APDS was characterized by recurrent respiratory infections, progressive airway damage, lymphopenia, increased circulating transitional B cells, increased immunoglobulin M, and reduced immunoglobulin G2 levels in serum and impaired vaccine responses. The E1021K mutation enhanced membrane association and kinase activity of p110δ. Patient-derived lymphocytes had increased levels of phosphatidylinositol 3,4,5-trisphosphate and phosphorylated AKT protein and were prone to activation-induced cell death. Selective p110δ inhibitors IC87114 and GS-1101 reduced the activity of the mutant enzyme in vitro, which suggested a therapeutic approach for patients with APDS. 10.1126/science.1243292
    C5a-mediated neutrophil dysfunction is RhoA-dependent and predicts infection in critically ill patients. Morris Andrew Conway,Brittan Mairi,Wilkinson Thomas S,McAuley Danny F,Antonelli Jean,McCulloch Corrienne,Barr Laura C,McDonald Neil A,Dhaliwal Kev,Jones Richard O,Mackellar Annie,Haslett Christopher,Hay Alasdair W,Swann David G,Anderson Niall,Laurenson Ian F,Davidson Donald J,Rossi Adriano G,Walsh Timothy S,Simpson A John Blood Critically ill patients are at heightened risk for nosocomial infections. The anaphylatoxin C5a impairs phagocytosis by neutrophils. However, the mechanisms by which this occurs and the relevance for acquisition of nosocomial infection remain undetermined. We aimed to characterize mechanisms by which C5a inhibits phagocytosis in vitro and in critically ill patients, and to define the relationship between C5a-mediated dysfunction and acquisition of nosocomial infection. In healthy human neutrophils, C5a significantly inhibited RhoA activation, preventing actin polymerization and phagocytosis. RhoA inhibition was mediated by PI3Kδ. The effects on RhoA, actin, and phagocytosis were fully reversed by GM-CSF. Parallel observations were made in neutrophils from critically ill patients, that is, impaired phagocytosis was associated with inhibition of RhoA and actin polymerization, and reversed by GM-CSF. Among a cohort of 60 critically ill patients, C5a-mediated neutrophil dysfunction (as determined by reduced CD88 expression) was a strong predictor for subsequent acquisition of nosocomial infection (relative risk, 5.8; 95% confidence interval, 1.5-22; P = .0007), and remained independent of time effects as assessed by survival analysis (hazard ratio, 5.0; 95% confidence interval, 1.3-8.3; P = .01). In conclusion, this study provides new insight into the mechanisms underlying immunocompromise in critical illness and suggests novel avenues for therapy and prevention of nosocomial infection. 10.1182/blood-2010-08-304667
    Phosphoinositide 3-kinase inhibition restores neutrophil accuracy in the elderly: toward targeted treatments for immunosenescence. Sapey Elizabeth,Greenwood Hannah,Walton Georgia,Mann Elizabeth,Love Alexander,Aaronson Natasha,Insall Robert H,Stockley Robert A,Lord Janet M Blood Immunosenescence is the functional deterioration of the immune system during natural aging. Despite increased susceptibility to bacterial infections in older adults, age-associated changes to neutrophil responses are only partially understood, and neutrophil migration has not been characterized in detail. Here we describe reduced chemotaxis but preserved chemokinesis toward a range of inflammatory stimuli in migrating neutrophils isolated from healthy older subjects. Cross-sectional data indicate that migratory behavior changes in the sixth decade of life. Crucially, aberrant migration may increase "bystander" tissue damage and heighten inflammation as a result of excess proteinase release during inaccurate chemotaxis, as well as reducing pathogen clearance. We show evidence of increased neutrophil proteinase activity in older adults, namely, raised levels of neutrophil proteinase substrate-derived peptides and evidence of primary granule release, associated with increased systemic inflammation. Inaccurate migration was causally associated with increased constitutive phosphoinositide 3-kinase (PI3K) signaling; untreated neutrophils from old donors demonstrated significant PI3K activation compared with cells from young donors. PI3K-blocking strategies, specifically inhibition of PI3Kγ or PI3Kδ, restored neutrophil migratory accuracy, whereas SHIP1 inhibition worsened migratory flaws. Targeting PI3K signaling may therefore offer a new strategy in improving neutrophil functions during infections and reduce inappropriate inflammation in older patients. 10.1182/blood-2013-08-519520
    A human immunodeficiency caused by mutations in the PIK3R1 gene. Deau Marie-Céline,Heurtier Lucie,Frange Pierre,Suarez Felipe,Bole-Feysot Christine,Nitschke Patrick,Cavazzana Marina,Picard Capucine,Durandy Anne,Fischer Alain,Kracker Sven The Journal of clinical investigation Recently, patient mutations that activate PI3K signaling have been linked to a primary antibody deficiency. Here, we used whole-exome sequencing and characterized the molecular defects in 4 patients from 3 unrelated families diagnosed with hypogammaglobulinemia and recurrent infections. We identified 2 different heterozygous splice site mutations that affect the same splice site in PIK3R1, which encodes the p85α subunit of PI3K. The resulting deletion of exon 10 produced a shortened p85α protein that lacks part of the PI3K p110-binding domain. The hypothetical loss of p85α-mediated inhibition of p110 activity was supported by elevated phosphorylation of the known downstream signaling kinase AKT in patient T cell blasts. Analysis of patient blood revealed that naive T and memory B cell counts were low, and T cell blasts displayed enhanced activation-induced cell death, which was corrected by addition of the PI3Kδ inhibitor IC87114. Furthermore, B lymphocytes proliferated weakly in response to activation via the B cell receptor and TLR9, indicating a B cell defect. The phenotype exhibited by patients carrying the PIK3R1 splice site mutation is similar to that of patients carrying gain-of-function mutations in PIK3CD. Our results suggest that PI3K activity is tightly regulated in T and B lymphocytes and that various defects in the PI3K-triggered pathway can cause primary immunodeficiencies. 10.1172/JCI75746
    MT1-MMP sheds LYVE-1 on lymphatic endothelial cells and suppresses VEGF-C production to inhibit lymphangiogenesis. Wong Hoi Leong Xavier,Jin Guoxiang,Cao Renhai,Zhang Shuo,Cao Yihai,Zhou Zhongjun Nature communications Lymphangiogensis is involved in various pathological conditions, such as arthritis and cancer metastasis. Although many factors have been identified to stimulate lymphatic vessel growth, little is known about lymphangiogenesis inhibitors. Here we report that membrane type 1-matrix metalloproteinase (MT1-MMP) is an endogenous suppressor of lymphatic vessel growth. MT1-MMP-deficient mice exhibit spontaneous corneal lymphangiogenesis without concomitant changes in angiogenesis. Mice lacking MT1-MMP in either lymphatic endothelial cells or macrophages recapitulate corneal lymphangiogenic phenotypes observed in Mmp14(-/-) mice, suggesting that the spontaneous lymphangiogenesis is both lymphatic endothelial cells autonomous and macrophage associated. Mechanistically, MT1-MMP directly cleaves LYVE-1 on lymphatic endothelial cells to inhibit LYVE-1-mediated lymphangiogenic responses. In addition, MT1-MMP-mediated PI3Kδ signalling restrains the production of VEGF-C from prolymphangiogenic macrophages through repressing the activation of NF-κB signalling. Thus, we identify MT1-MMP as an endogenous inhibitor of physiological lymphangiogenesis. 10.1038/ncomms10824
    Targeting nonclassical oncogenes for therapy in T-ALL. Subramaniam Prem S,Whye Dosh W,Efimenko Evgeni,Chen Jianchung,Tosello Valeria,De Keersmaecker Kim,Kashishian Adam,Thompson Mary Ann,Castillo Mireia,Cordon-Cardo Carlos,Davé Utpal P,Ferrando Adolfo,Lannutti Brian J,Diacovo Thomas G Cancer cell Constitutive phosphoinositide 3-kinase (PI3K)/Akt activation is common in T cell acute lymphoblastic leukemia (T-ALL). Although four distinct class I PI3K isoforms (α, β, γ, δ) could participate in T-ALL pathogenesis, none has been implicated in this process. We report that in the absence of PTEN phosphatase tumor suppressor function, PI3Kγ or PI3Kδ alone can support leukemogenesis, whereas inactivation of both isoforms suppressed tumor formation. The reliance of PTEN null T-ALL on the combined activities of PI3Kγ/δ was further demonstrated by the ability of a dual inhibitor to reduce disease burden and prolong survival in mice as well as prevent proliferation and promote activation of proapoptotic pathways in human tumors. These results support combined inhibition of PI3Kγ/δ as therapy for T-ALL. 10.1016/j.ccr.2012.02.029
    PI3K and cancer: lessons, challenges and opportunities. Fruman David A,Rommel Christian Nature reviews. Drug discovery The central role of phosphoinositide 3-kinase (PI3K) activation in tumour cell biology has prompted a sizeable effort to target PI3K and/or downstream kinases such as AKT and mammalian target of rapamycin (mTOR) in cancer. However, emerging clinical data show limited single-agent activity of inhibitors targeting PI3K, AKT or mTOR at tolerated doses. One exception is the response to PI3Kδ inhibitors in chronic lymphocytic leukaemia, where a combination of cell-intrinsic and -extrinsic activities drive efficacy. Here, we review key challenges and opportunities for the clinical development of inhibitors targeting the PI3K-AKT-mTOR pathway. Through a greater focus on patient selection, increased understanding of immune modulation and strategic application of rational combinations, it should be possible to realize the potential of this promising class of targeted anticancer agents. 10.1038/nrd4204
    New insights into pre-BCR and BCR signalling with relevance to B cell malignancies. Rickert Robert C Nature reviews. Immunology The B cell receptor (BCR) and its precursor (pre-BCR) control B cell homeostasis, differentiation and function. Moreover, aberrant pre-BCR and BCR signalling have a central role in B cell neoplasia; for example, enhanced positive signalling or disrupted negative signalling downstream of the pre-BCR promotes B cell acute lymphocytic leukaemia. The emerging distinctions between tonic and chronic active BCR signalling have contributed to the identification of oncogenic targets downstream of BCR signalling in mature B cell neoplasms. Indeed, the encouraging results of several ongoing clinical trials that target the activity of phosphoinositide 3-kinase δ-isoform (PI3Kδ), Bruton tyrosine kinase (BTK) or spleen tyrosine kinase (SYK) downstream of the BCR highlight the therapeutic potential of inhibiting BCR signalling. 10.1038/nri3487
    PI3'-kinase inhibition forestalls the onset of MEK1/2 inhibitor resistance in BRAF-mutated melanoma. Deuker Marian M,Marsh Durban Victoria,Phillips Wayne A,McMahon Martin Cancer discovery UNLABELLED:Phosphatidylinositide 3' (PI3')-lipid signaling cooperates with oncogenic BRAF(V600E) to promote melanomagenesis. Sustained PI3'-lipid production commonly occurs via silencing of the PI3'-lipid phosphatase PTEN or, less commonly, through mutational activation of PIK3CA, encoding the 110-kDa catalytic subunit of PI3'-kinase-α (PI3Kα). To define the PI3K catalytic isoform dependency of BRAF-mutated melanoma, we used pharmacologic, isoform-selective PI3K inhibitors in conjunction with melanoma-derived cell lines and genetically engineered mouse (GEM) models. Although BRAF(V600E)/PIK3CA(H1047R) melanomas were sensitive to the antiproliferative effects of selective PI3Kα blockade, inhibition of BRAF(V600E)/PTEN(Null) melanoma proliferation required combined blockade of PI3Kα, PI3Kδ, and PI3Kγ, and was insensitive to PI3Kβ blockade. In GEM models, isoform-selective PI3K inhibition elicited cytostatic effects, but significantly potentiated melanoma regression in response to BRAF(V600E) pathway-targeted inhibition. Interestingly, PI3K inhibition forestalled the onset of MEK inhibitor resistance in two independent GEM models of BRAF(V600E)-driven melanoma. These results suggest that combination therapy with PI3K inhibitors may be a useful strategy to extend the duration of clinical response of patients with BRAF-mutated melanoma to BRAF(V600E) pathway-targeted therapies. SIGNIFICANCE:Although BRAF(V600E) pathway-targeted therapies elicit melanoma regression, the onset of drug resistance limits the durability of response. Here, we show that combined treatment with PI3K inhibitors significantly forestalled the onset of MEK1/2 inhibitor-resistant disease in BRAF-mutated GEM melanoma models. These results provide a conceptual framework for the combined deployment of BRAF(V600E) plus PI3K pathway-targeted inhibitors in the treatment of a subset of patients with BRAF-mutated melanoma. 10.1158/2159-8290.CD-14-0856
    Parsaclisib Has Activity in Patients with B-cell Malignancies. Cancer discovery A next-generation PI3Kδ inhibitor achieved objective responses and long-term tolerability in NHL. 10.1158/2159-8290.CD-RW2019-031
    Umbralisib: Treatment for a Rare Lymphoma? Cancer discovery The PI3Kδ inhibitor umbralisib may be a promising therapy for patients with relapsed/refractory marginal zone lymphoma: In the phase IIb UNITY-NHL trial, the drug elicited a response rate of 55%. In addition, patients had a 1-year progression-free survival rate of 71%, with manageable side effects. 10.1158/2159-8290.CD-NB2019-045
    Targeting PI3K in Cancer: Impact on Tumor Cells, Their Protective Stroma, Angiogenesis, and Immunotherapy. Okkenhaug Klaus,Graupera Mariona,Vanhaesebroeck Bart Cancer discovery The PI3K pathway is hyperactivated in most cancers, yet the capacity of PI3K inhibitors to induce tumor cell death is limited. The efficacy of PI3K inhibition can also derive from interference with the cancer cells' ability to respond to stromal signals, as illustrated by the approved PI3Kδ inhibitor idelalisib in B-cell malignancies. Inhibition of the leukocyte-enriched PI3Kδ or PI3Kγ may unleash antitumor T-cell responses by inhibiting regulatory T cells and immune-suppressive myeloid cells. Moreover, tumor angiogenesis may be targeted by PI3K inhibitors to enhance cancer therapy. Future work should therefore also explore the effects of PI3K inhibitors on the tumor stroma, in addition to their cancer cell-intrinsic impact. SIGNIFICANCE:The PI3K pathway extends beyond the direct regulation of cancer cell proliferation and survival. In B-cell malignancies, targeting PI3K purges the tumor cells from their protective microenvironment. Moreover, we propose that PI3K isoform-selective inhibitors may be exploited in the context of cancer immunotherapy and by targeting angiogenesis to improve drug and immune cell delivery. Cancer Discov; 6(10); 1090-105. ©2016 AACR. 10.1158/2159-8290.CD-16-0716
    Transient targeting of phosphoinositide 3-kinase acts as a roadblock in mast cells' route to allergy. Collmann Emilie,Bohnacker Thomas,Marone Romina,Dawson Janet,Rehberg Markus,Stringer Rowan,Krombach Fritz,Burkhart Christoph,Hirsch Emilio,Hollingworth Gregory J,Thomas Matthew,Wymann Matthias P The Journal of allergy and clinical immunology BACKGROUND:Tissue mast cell numbers are dynamically regulated by recruitment of progenitors from the vasculature. It is unclear whether progenitors are recruited during allergic sensitization and whether recruitment promotes allergic responses. OBJECTIVE:We sought to (1) determine the effect of mast cell recruitment on acute allergic responses and (2) to define the role of phosphoinositide 3-kinase (PI3K) isoforms in sequential steps to allergic responses. METHODS:Gene-targeted mice for PI3Kγ or PI3Kδ or mice treated with isoform-specific PI3K inhibitors (a novel PI3Kγ-specific inhibitor [NVS-PI3-4] and the PI3Kδ inhibitor IC87114) were used to monitor IgE-mediated mast cell recruitment, migration, adhesion by means of intravital microscopy, degranulation, TNF-α release, and subsequent endothelial cell activation in vivo or in bone marrow-derived mast cells. RESULTS:Functional PI3Kγ, but not PI3Kδ, was crucial for mast cell accumulation in IgE-challenged skin, TNF-α release from IgE/antigen-stimulated mast cells, and mast cell/endothelial interactions and chemotaxis. PI3Kγ-deficient bone marrow-derived mast cells did not adhere to the endothelium in TNF-α-treated cremaster muscle, whereas PI3Kδ was not required. Depletion of TNF-α blocked IgE-induced mast cell recruitment, which links tissue mast cell-derived cytokine release to endothelial activation and mast cell recruitment. Interference with mast cell recruitment protected against anaphylaxis and was superior to blockage of tissue mast cell degranulation. CONCLUSIONS:Interference with mast cell recruitment to exacerbated tissues provides a novel strategy to alleviate allergic reactions and surpassed attenuation of tissue mast cell degranulation. This results in prolonged drug action and allows for reduction of drug doses required to block anaphylaxis, an important feature for drugs targeting inflammatory disease in general. 10.1016/j.jaci.2013.03.008
    A role for phosphoinositol 3-kinase delta in the impairment of glucocorticoid responsiveness in patients with chronic obstructive pulmonary disease. Marwick John A,Caramori Gaetano,Casolari Paolo,Mazzoni Federico,Kirkham Paul A,Adcock Ian M,Chung Kian Fan,Papi Alberto The Journal of allergy and clinical immunology BACKGROUND:Glucocorticoid function is markedly impaired in the lungs of patients with chronic obstructive pulmonary disease (COPD). This reduction in glucocorticoid sensitivity might be due to an oxidant-mediated increase in phosphoinositol 3-kinase (PI3K) delta signaling. OBJECTIVE:We sought to determine the role of PI3Kdelta in the reduced glucocorticoid responsiveness in patients with COPD. METHODS:Peripheral lung tissue was obtained from 24 patients with COPD, 20 age-matched smokers with normal lung function, and 13 nonsmokers. Peripheral blood monocytes were isolated from 9 patients with COPD and 7 age-matched smokers with normal lung function and from healthy volunteers. RESULTS:The expressions of PI3Kdelta and Akt phosphorylation were increased in macrophages from patients with COPD compared with those from control groups of age-matched smokers and nonsmokers. In vitro oxidative stress induced phosphorylation of Akt in monocytes and macrophages, which was abolished by means of selective inhibition of PI3Kdelta but not PI3Kgamma. Dexamethasone was less effective at repressing LPS-induced GM-CSF and CXC motif chemokine 8 release in blood monocytes from patients with COPD compared with age-matched smokers. This reduced sensitivity was reversed by inhibition of PI3Kdelta but not PI3Kgamma. CONCLUSION:PI3Kdelta expression and signaling is increased in the lungs of patients with COPD. Selective inhibition of PI3Kdelta might restore glucocorticoid function in patients with COPD and might therefore present a potential therapeutic target. 10.1016/j.jaci.2010.02.003
    Clinical spectrum and features of activated phosphoinositide 3-kinase δ syndrome: A large patient cohort study. Coulter Tanya I,Chandra Anita,Bacon Chris M,Babar Judith,Curtis James,Screaton Nick,Goodlad John R,Farmer George,Steele Cathal Laurence,Leahy Timothy Ronan,Doffinger Rainer,Baxendale Helen,Bernatoniene Jolanta,Edgar J David M,Longhurst Hilary J,Ehl Stephan,Speckmann Carsten,Grimbacher Bodo,Sediva Anna,Milota Tomas,Faust Saul N,Williams Anthony P,Hayman Grant,Kucuk Zeynep Yesim,Hague Rosie,French Paul,Brooker Richard,Forsyth Peter,Herriot Richard,Cancrini Caterina,Palma Paolo,Ariganello Paola,Conlon Niall,Feighery Conleth,Gavin Patrick J,Jones Alison,Imai Kohsuke,Ibrahim Mohammad A A,Markelj Gašper,Abinun Mario,Rieux-Laucat Frédéric,Latour Sylvain,Pellier Isabelle,Fischer Alain,Touzot Fabien,Casanova Jean-Laurent,Durandy Anne,Burns Siobhan O,Savic Sinisa,Kumararatne D S,Moshous Despina,Kracker Sven,Vanhaesebroeck Bart,Okkenhaug Klaus,Picard Capucine,Nejentsev Sergey,Condliffe Alison M,Cant Andrew James The Journal of allergy and clinical immunology BACKGROUND:Activated phosphoinositide 3-kinase δ syndrome (APDS) is a recently described combined immunodeficiency resulting from gain-of-function mutations in PIK3CD, the gene encoding the catalytic subunit of phosphoinositide 3-kinase δ (PI3Kδ). OBJECTIVE:We sought to review the clinical, immunologic, histopathologic, and radiologic features of APDS in a large genetically defined international cohort. METHODS:We applied a clinical questionnaire and performed review of medical notes, radiology, histopathology, and laboratory investigations of 53 patients with APDS. RESULTS:Recurrent sinopulmonary infections (98%) and nonneoplastic lymphoproliferation (75%) were common, often from childhood. Other significant complications included herpesvirus infections (49%), autoinflammatory disease (34%), and lymphoma (13%). Unexpectedly, neurodevelopmental delay occurred in 19% of the cohort, suggesting a role for PI3Kδ in the central nervous system; consistent with this, PI3Kδ is broadly expressed in the developing murine central nervous system. Thoracic imaging revealed high rates of mosaic attenuation (90%) and bronchiectasis (60%). Increased IgM levels (78%), IgG deficiency (43%), and CD4 lymphopenia (84%) were significant immunologic features. No immunologic marker reliably predicted clinical severity, which ranged from asymptomatic to death in early childhood. The majority of patients received immunoglobulin replacement and antibiotic prophylaxis, and 5 patients underwent hematopoietic stem cell transplantation. Five patients died from complications of APDS. CONCLUSION:APDS is a combined immunodeficiency with multiple clinical manifestations, many with incomplete penetrance and others with variable expressivity. The severity of complications in some patients supports consideration of hematopoietic stem cell transplantation for severe childhood disease. Clinical trials of selective PI3Kδ inhibitors offer new prospects for APDS treatment. 10.1016/j.jaci.2016.06.021
    Phosphatidylinositol 3-kinase δ blockade increases genomic instability in B cells. Compagno Mara,Wang Qi,Pighi Chiara,Cheong Taek-Chin,Meng Fei-Long,Poggio Teresa,Yeap Leng-Siew,Karaca Elif,Blasco Rafael B,Langellotto Fernanda,Ambrogio Chiara,Voena Claudia,Wiestner Adrian,Kasar Siddha N,Brown Jennifer R,Sun Jing,Wu Catherine J,Gostissa Monica,Alt Frederick W,Chiarle Roberto Nature Activation-induced cytidine deaminase (AID) is a B-cell-specific enzyme that targets immunoglobulin genes to initiate class switch recombination and somatic hypermutation. In addition, through off-target activity, AID has a much broader effect on genomic instability by initiating oncogenic chromosomal translocations and mutations involved in the development and progression of lymphoma. AID expression is tightly regulated in B cells and its overexpression leads to enhanced genomic instability and lymphoma formation. The phosphatidylinositol 3-kinase δ (PI3Kδ) pathway regulates AID by suppressing its expression in B cells. Drugs for leukaemia or lymphoma therapy such as idelalisib, duvelisib and ibrutinib block PI3Kδ activity directly or indirectly, potentially affecting AID expression and, consequently, genomic stability in B cells. Here we show that treatment of primary mouse B cells with idelalisib or duvelisib, and to a lesser extent ibrutinib, enhanced the expression of AID and increased somatic hypermutation and chromosomal translocation frequency to the Igh locus and to several AID off-target sites. Both of these effects were completely abrogated in AID-deficient B cells. PI3Kδ inhibitors or ibrutinib increased the formation of AID-dependent tumours in pristane-treated mice. Consistently, PI3Kδ inhibitors enhanced AID expression and translocation frequency to IGH and AID off-target sites in human chronic lymphocytic leukaemia and mantle cell lymphoma cell lines, and patients treated with idelalisib, but not ibrutinib, showed increased somatic hypermutation in AID off-targets. In summary, we show that PI3Kδ or Bruton's tyrosine kinase inhibitors increase genomic instability in normal and neoplastic B cells by an AID-dependent mechanism. This effect should be carefully considered, as such inhibitors can be administered to patients for years. 10.1038/nature21406
    Phosphatidylinositol 3-kinase delta pathway: a novel therapeutic target for Sjögren's syndrome. Nayar Saba,Campos Joana,Smith Charlotte G,Iannizzotto Valentina,Gardner David H,Colafrancesco Serena,Pipi Elena,Kollert Florian,Hunter Kelly J,Brewer Charlotte,Buckley Christopher Dominic,Bowman Simon J,Priori Roberta,Valesini Guido,Juarez Maria,Fahy William A,Fisher Benjamin A,Payne Andrew,Allen Rodger A,Barone Francesca Annals of the rheumatic diseases BACKGROUND:The phosphatidylinositol 3-kinase delta isoform (PI3Kδ) belongs to an intracellular lipid kinase family that regulate lymphocyte metabolism, survival, proliferation, apoptosis and migration and has been successfully targeted in B-cell malignancies. Primary Sjögren's syndrome (pSS) is a chronic immune-mediated inflammatory disease characterised by exocrine gland lymphocytic infiltration and B-cell hyperactivation which results in systemic manifestations, autoantibody production and loss of glandular function. Given the central role of B cells in pSS pathogenesis, we investigated PI3Kδ pathway activation in pSS and the functional consequences of blocking PI3Kδ in a murine model of focal sialoadenitis that mimics some features of pSS. METHODS AND RESULTS:Target validation assays showed significant expression of phosphorylated ribosomal protein S6 (pS6), a downstream mediator of the phosphatidylinositol 3-kinase delta (PI3Kδ) pathway, within pSS salivary glands. pS6 distribution was found to co-localise with T/B cell markers within pSS aggregates and the CD138+ plasma cells infiltrating the glands. In vivo blockade of PI3Kδ activity with seletalisib, a PI3Kδ-selective inhibitor, in a murine model of focal sialoadenitis decreased accumulation of lymphocytes and plasma cells within the glands of treated mice in the prophylactic and therapeutic regimes. Additionally, production of lymphoid chemokines and cytokines associated with ectopic lymphoneogenesis and, remarkably, saliva flow and autoantibody production, were significantly affected by treatment with seletalisib. CONCLUSION:These data demonstrate activation of PI3Kδ pathway within the glands of patients with pSS and its contribution to disease pathogenesis in a model of disease, supporting the exploration of the therapeutic potential of PI3Kδ pathway inhibition in this condition. 10.1136/annrheumdis-2017-212619
    Leukemic challenge unmasks a requirement for PI3Kdelta in NK cell-mediated tumor surveillance. Zebedin Eva,Simma Olivia,Schuster Christian,Putz Eva Maria,Fajmann Sabine,Warsch Wolfgang,Eckelhart Eva,Stoiber Dagmar,Weisz Eva,Schmid Johannes A,Pickl Winfried F,Baumgartner Christian,Valent Peter,Piekorz Roland P,Freissmuth Michael,Sexl Veronika Blood Specific inhibitors of PI3K isoforms are currently evaluated for their therapeutic potential in leukemia. We found that BCR/ABL(+) human leukemic cells express PI3Kdelta and therefore explored its impact on leukemia development. Using PI3Kdelta-deficient mice, we define a dual role of PI3Kdelta in leukemia. We observed a growth-promoting effect in tumor cells and an essential function in natural killer (NK) cell-mediated tumor surveillance: Abelson-transformed PI3Kdelta-deficient cells induced leukemia in RAG2-deficient mice with an increased latency, indicating that PI3Kdelta accelerated leukemia progression in vivo. However, the absence of PI3Kdelta also affected NK cell-mediated tumor surveillance. PI3Kdelta-deficient NK cells failed to lyse a large variety of target cells because of defective degranulation, as also documented by capacitance recordings. Accordingly, transplanted leukemic cells killed PI3Kdelta-deficient animals more rapidly. As a net effect, no difference in disease latency in vivo was detected if both leukemic cells and NK cells lack PI3Kdelta. Other tumor models confirmed that PI3Kdelta-deficient mice succumbed more rapidly when challenged with T- or B-lymphoid leukemic or B16 melanoma cells. Thus, the action of PI3Kdelta in the NK compartment is as relevant to survival of the mice as the delayed tumor progression. This dual function must be taken into account when using PI3Kdelta inhibitors as antileukemic agents in clinical trials. 10.1182/blood-2008-02-139105
    Silencing c-Myc translation as a therapeutic strategy through targeting PI3Kδ and CK1ε in hematological malignancies. Deng Changchun,Lipstein Mark R,Scotto Luigi,Jirau Serrano Xavier O,Mangone Michael A,Li Shirong,Vendome Jeremie,Hao Yun,Xu Xiaoming,Deng Shi-Xian,Realubit Ronald B,Tatonetti Nicholas P,Karan Charles,Lentzsch Suzanne,Fruman David A,Honig Barry,Landry Donald W,O'Connor Owen A Blood Phosphoinositide 3-kinase (PI3K) and the proteasome pathway are both involved in activating the mechanistic target of rapamycin (mTOR). Because mTOR signaling is required for initiation of messenger RNA translation, we hypothesized that cotargeting the PI3K and proteasome pathways might synergistically inhibit translation of c-Myc. We found that a novel PI3K δ isoform inhibitor TGR-1202, but not the approved PI3Kδ inhibitor idelalisib, was highly synergistic with the proteasome inhibitor carfilzomib in lymphoma, leukemia, and myeloma cell lines and primary lymphoma and leukemia cells. TGR-1202 and carfilzomib (TC) synergistically inhibited phosphorylation of the eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1), leading to suppression of c-Myc translation and silencing of c-Myc-dependent transcription. The synergistic cytotoxicity of TC was rescued by overexpression of eIF4E or c-Myc. TGR-1202, but not other PI3Kδ inhibitors, inhibited casein kinase-1 ε (CK1ε). Targeting CK1ε using a selective chemical inhibitor or short hairpin RNA complements the effects of idelalisib, as a single agent or in combination with carfilzomib, in repressing phosphorylation of 4E-BP1 and the protein level of c-Myc. These results suggest that TGR-1202 is a dual PI3Kδ/CK1ε inhibitor, which may in part explain the clinical activity of TGR-1202 in aggressive lymphoma not found with idelalisib. Targeting CK1ε should become an integral part of therapeutic strategies targeting translation of oncogenes such as c-Myc. 10.1182/blood-2016-08-731240
    Phase II study of idelalisib, a selective inhibitor of PI3Kδ, for relapsed/refractory classical Hodgkin lymphoma. Gopal A K,Fanale M A,Moskowitz C H,Shustov A R,Mitra S,Ye W,Younes A,Moskowitz A J Annals of oncology : official journal of the European Society for Medical Oncology Background:The phosphatidylinositol-3-kinase delta (PI3Kδ) inhibitor idelalisib has been shown to block downstream intracellular signaling, reduce the production of prosurvival chemokines and induce apoptosis in classical Hodgkin lymphoma (HL) cell lines. It has also been shown to inhibit regulatory T cells and myeloid-derived suppressor cells in other tumor models. We hypothesized that inhibiting PI3Kδ would have both direct and indirect antitumor effects by directly targeting the malignant cells as well as modulating the inflammatory microenvironment. We tested this hypothesis in a phase II study. Patients and methods:We enrolled 25 patients with relapsed/refractory HL with a median age of 42 years and who had previously received a median of five therapies including 18 (72%) with failed autologous stem cell transplant, 23 (92%) with failed brentuximab vedotin, and 11 (44%) with prior radiation therapy. Idelalisib was administered at 150 mg two times daily; an increase to 300 mg two times daily was permitted at the time of disease progression. Results:The overall response rate to idelalisib therapy was 20% (95% confidence interval: 6.8%, 40.7%) with a median time to response of 2.0 months. Seventeen patients (68%) experienced reduction in target lesions with one complete remission and four partial remissions. The median duration of response was 8.4 months and median progression-free survival was 2.3 months. The most common grade ≥3 adverse event was elevation of alanine aminotransferase (two patients, 8%). Diarrhea/colitis was seen in three patients and was grade 1-2. There was one adverse event leading to death (hypoxia). Conclusions:Idelalisib was tolerable and had modest single-agent activity in heavily pretreated patients with HL. Rational combinations with other novel agents may improve response rate and duration of response. Clinical trial registration:ClinicalTrials.gov # NCT01393106. 10.1093/annonc/mdx028
    PI3Kδ and primary immunodeficiencies. Lucas Carrie L,Chandra Anita,Nejentsev Sergey,Condliffe Alison M,Okkenhaug Klaus Nature reviews. Immunology Primary immunodeficiencies are inherited disorders of the immune system, often caused by the mutation of genes required for lymphocyte development and activation. Recently, several studies have identified gain-of-function mutations in the phosphoinositide 3-kinase (PI3K) genes PIK3CD (which encodes p110δ) and PIK3R1 (which encodes p85α) that cause a combined immunodeficiency syndrome, referred to as activated PI3Kδ syndrome (APDS; also known as p110δ-activating mutation causing senescent T cells, lymphadenopathy and immunodeficiency (PASLI)). Paradoxically, both loss-of-function and gain-of-function mutations that affect these genes lead to immunosuppression, albeit via different mechanisms. Here, we review the roles of PI3Kδ in adaptive immunity, describe the clinical manifestations and mechanisms of disease in APDS and highlight new insights into PI3Kδ gleaned from these patients, as well as implications of these findings for clinical therapy. 10.1038/nri.2016.93
    Umbralisib, a novel PI3Kδ and casein kinase-1ε inhibitor, in relapsed or refractory chronic lymphocytic leukaemia and lymphoma: an open-label, phase 1, dose-escalation, first-in-human study. Burris Howard A,Flinn Ian W,Patel Manish R,Fenske Timothy S,Deng Changchun,Brander Danielle M,Gutierrez Martin,Essell James H,Kuhn John G,Miskin Hari P,Sportelli Peter,Weiss Michael S,Vakkalanka Swaroop,Savona Michael R,O'Connor Owen A The Lancet. Oncology BACKGROUND:Umbralisib (TGR-1202) is a novel next-generation inhibitor of phosphatidylinositol 3-kinase (PI3K) isoform p110δ (PI3Kδ), which is structurally distinct from other PI3Kδ inhibitors and shows improved isoform selectivity. Umbralisib also uniquely inhibits casein kinase-1ε, a major regulator of protein translation. The aim of this first-in-human phase 1 study was to establish the safety and preliminary activity profile of umbralisib in patients with haematological malignancies. METHODS:We did an open-label, phase 1, dose-escalation study at seven clinics in the USA. We recruited patients aged at least 18 years with relapsed or refractory chronic lymphocytic leukaemia or small lymphocytic lymphoma, B-cell and T-cell non-Hodgkin lymphoma, or Hodgkin's lymphoma, who had received one or more previous lines of therapy, with measurable and assessable disease, and adequate organ system function. Patients self-administered an umbralisib oral tablet once per day in 28-day cycles, with dose escalation done in a traditional 3 + 3 design to establish safety and determine the maximum tolerated dose. In initial cohorts, patients took umbralisib in a fasting state at a starting dose of 50 mg, increasing to 100, 200, 400, 800, 1200, and 1800 mg until the maximum tolerated dose was reached, or the maximal dose cohort was accrued without a dose-limiting toxicity. Subsequent cohorts self-administered a micronised formulation of umbralisib tablet in a fed state at an initial dose of 200 mg, increased in increments to 400, 800, 1200, and 1800 mg until the maximum tolerated dose or the maximal dose level was accrued. In August, 2014, all patients still on study were transitioned to 800 mg of the micronised formulation and dosing of the initial formulation was discontinued. The primary endpoints of the study were investigator-assessed safety in all treated patients (the safety population), the maximum tolerated dose, and the pharmacokinetics of umbralisib. Secondary endpoints included preliminary assessments of anti-cancer activity (objective responses and duration of response). Follow-up stopped for a patient once they discontinued therapy. This study has been completed and is registered with ClinicalTrials.gov, number NCT01767766. FINDINGS:Between Jan 17, 2013, and Jan 14, 2016, we enrolled and treated 90 patients with umbralisib. The median duration of treatment and follow-up was 4·7 cycles (IQR 2·0-14·0) or 133 days (IQR 55-335). The most common treatment-emergent adverse events irrespective of causality were diarrhoea (in 39 [43%] of 90 patients), nausea (38 [42%]), and fatigue (28 [31%]). The most common grade 3 or 4 adverse events were neutropenia (in 12 [13%] patients), anaemia (eight [9%]) and thrombocytopenia (six [7%]). Serious adverse events considered at least possibly related to umbralisib occurred in seven patients: pneumonia in three (3%) patients, lung infection in one (1%), febrile neutropenia in one (1%), and colitis in two (2%), one of whom also had febrile neutropenia. The maximum tolerated dose was 1200 mg of the micronised formulation, with 800 mg of this formulation selected as the recommended phase 2 dose. Both cases of colitis occurred at above the recommended phase 2 dose. 33 (37%) of the 90 patients enrolled had an objective response to treatment with umbralisib. INTERPRETATION:Umbralisib was well tolerated and showed preliminary signs of activity in patients with relapsed or refractory haematological malignancies. The safety profile of umbralisib in this phase 1 study was distinct from that of other PI3Kδ inhibitors, with fewer occurrences of autoimmune-like toxicities such as colitis. These findings warrant further evaluation of this agent in this setting. FUNDING:TG Therapeutics. 10.1016/S1470-2045(18)30082-2
    Activated PI3 Kinase Delta Syndrome: From Genetics to Therapy. Michalovich David,Nejentsev Sergey Frontiers in immunology Activated PI3 kinase delta syndrome (APDS) is a primary immunodeficiency caused by dominant mutations that increase activity of phosphoinositide-3-kinase δ (PI3Kδ). APDS can be caused by mutations in the gene that encodes PI3Kδ catalytic subunit p110δ (APDS1) or mutations in the gene that encodes regulatory subunit p85α (APDS2). APDS research advanced rapidly after the initial discovery in 2013. More than 200 APDS patients have been identified around the world. Multiple novel APDS mutations were reported and molecular mechanisms leading to PI3Kδ activation have been elucidated. The finding of APDS significantly increased our understanding of the role of PI3Kδ in the human immune system. Perhaps most importantly, discovery of the molecular basis of this primary immunodeficiency suggested that APDS patients, who previously received only non-specific therapy, could be treated by a novel class of drugs that inhibits PI3Kδ activity. This led to the ongoing clinical trials of selective PI3Kδ inhibitors in APDS patients. Overall, the APDS story provides an excellent example of translational research, beginning with patients who had an unknown disease cause and leading to a novel specific knowledge-based treatment. 10.3389/fimmu.2018.00369
    PI3K pathway defects leading to immunodeficiency and immune dysregulation. Nunes-Santos Cristiane J,Uzel Gulbu,Rosenzweig Sergio D The Journal of allergy and clinical immunology The phosphatidylinositol 3-kinase (PI3K) signaling pathway is involved in a broad range of cellular processes, including growth, metabolism, differentiation, proliferation, motility, and survival. The PI3Kδ enzyme complex is primarily present in the immune system and comprises a catalytic (p110δ) and regulatory (p85α) subunit. Dynamic regulation of PI3Kδ activity is required to ensure normal function and differentiation of immune cells. In the last decade, discovery of germline mutations in genes involved in the PI3Kδ pathway (PIK3CD, PIK3R1, or phosphatase and tensin homolog [PTEN]) proved that both overactivation and underactivation (gain of function and loss of function, respectively) of PI3Kδ lead to impaired and dysregulated immunity. Although a small group of patients reported to underactivate PI3Kδ show predominantly humoral defects and autoimmune features, more than 200 patients have been described with overactivation of PI3Kδ, presenting with a much more complex phenotype of combined immunodeficiency and immune dysregulation. The clinical and immunologic characterization, as well as current pathophysiologic understanding and specific therapies for PI3K pathway defects leading to immunodeficiency and immune dysregulation, are reviewed here. 10.1016/j.jaci.2019.03.017
    Phosphoinositide 3-kinase δ regulates migration and invasion of synoviocytes in rheumatoid arthritis. Bartok Beatrix,Hammaker Deepa,Firestein Gary S Journal of immunology (Baltimore, Md. : 1950) Cartilage destruction mediated by invasive fibroblast-like synoviocytes (FLS) plays a central role in pathogenesis of rheumatoid arthritis (RA). Increased cell migration and degradation of extracellular matrix are fundamental to these processes. The class I PI3Ks control cell survival, proliferation, and migration, which might be involved in cartilage damage in RA. PI3Kδ isoform was recently identified as a key regulator of FLS growth and survival, suggesting that it could contribute to synoviocyte aggressive behavior. Therefore, we assessed the role of PI3Kδ in RA synoviocyte migration and invasion. We observed that PI3Kδ inhibition or small interfering RNA knockdown decreased platelet-derived growth factor (PDGF)-mediated migration and invasion of FLS. We then showed that PI3Kδ regulates the organization of actin cytoskeleton and lamellipodium formation during PDGF stimulation. To gain insight into molecular mechanisms, we examined the effect of PI3Kδ inhibition on Rac1/PAK, FAK, and JNK activation. Our studies suggest that Rac1/PAK is key target of PDGF-mediated PI3Kδ signaling, whereas FAK and JNK are not involved. Thus, PI3Kδ contributes to multiple aspects of the pathogenic FLS behavior in RA. These observations, together with previous findings that PI3Kδ regulates FLS growth and survival, suggest that PI3Kδ inhibition could be chondroprotective in RA by modulating synoviocyte growth, migration, and invasion. 10.4049/jimmunol.1300950
    PI3Kδ and PI3Kγ as targets for autoimmune and inflammatory diseases. Cushing Timothy D,Metz Daniela P,Whittington Douglas A,McGee Lawrence R Journal of medicinal chemistry 10.1021/jm300847w
    Signalling: PI3Kδ keeps TLR4 signalling on track. Papatriantafyllou Maria Nature reviews. Immunology 10.1038/nri3330
    Phosphoinositide 3-Kinase P110δ-Signaling Is Critical for Microbiota-Activated IL-10 Production by B Cells that Regulate Intestinal Inflammation. Oka Akihiko,Mishima Yoshiyuki,Liu Bo,Herzog Jeremy W,Steinbach Erin C,Kobayashi Taku,Plevy Scott E,Sartor R Balfour Cells The phosphoinositide 3-kinase catalytic subunit p110δ (PI3Kδ) gene maps to a human inflammatory bowel diseases (IBD) susceptibility locus, and genetic deletion of PI3Kδ signaling causes spontaneous colitis in mice. However, little is known regarding the role of PI3Kδ on IL-10-producing B cells that help regulate mucosal inflammation in IBD. We investigated the role of PI3Kδ signaling in B cell production of IL-10, following stimulation by resident bacteria and B cell regulatory function against colitis. In vitro, B cells from PI3Kδ mice or wild-type B cells treated with PI3K specific inhibitors secreted significantly less IL-10 with greater IL-12p40 following bacterial stimulation. These B cells failed to suppress inflammatory cytokines by co-cultured microbiota-activated macrophages or CD4 T cells. In vivo, co-transferred wild-type B cells ameliorated T cell-mediated colitis, while PI3Kδ B cells did not confer protection from mucosal inflammation. These results indicate that PI3Kδ-signaling mediates regulatory B cell immune differentiation when stimulated with resident microbiota or their components, and is critical for induction and regulatory function of IL-10-producing B cells in intestinal homeostasis and inflammation. 10.3390/cells8101121
    Taking PI3Kδ and PI3Kγ one step ahead: dual active PI3Kδ/γ inhibitors for the treatment of immune-mediated inflammatory diseases. Rommel Christian Current topics in microbiology and immunology The multiple roles of PI3Kδ (p110δ) and PI3Kγ (p110γ) in various immune cells have encouraged the development of small-molecule inhibitors of both PI3K isoforms, alone or in combination, for the treatment of immune-mediated inflamatory diseases. Recent findings suggest a previously unrecognized interdependent cooperativity between p110δ and p110γ, if not all class I PI3K isoforms, expressed and activated in leukocytes and endothelium. For example, the activity of p110δ and p110γ in combination appears to be necessary for mediating efficient (velocity and direction) trafficking of immune competent cells to sites of inflammation. This chapter will focus on the emerging evidence of the dynamic interplay of p110δ and p110γ supporting the hypothesis that dual-blockade of both, p110δ and p110γ, presents a unique therapeutic opportunity in that pharmacological inhibition of the two PI3K isoforms simultaneously may yield superior clinical results in the treatment of a variety of complex immune-mediated inflammatory diseases. 10.1007/82_2010_79
    Idelalisib--a PI3Kδ inhibitor for B-cell cancers. Fruman David A,Cantley Lewis C The New England journal of medicine 10.1056/NEJMe1400055
    Haematological cancer: idelalisib-targeting PI3Kδ in patients with B-cell malignancies. Burger Jan A,Okkenhaug Klaus Nature reviews. Clinical oncology 10.1038/nrclinonc.2014.42
    Idelalisib: targeting PI3Kδ in B-cell malignancies. Gilbert Judith A The Lancet. Oncology 10.1016/s1470-2045(14)70052-x
    Glatiramer acetate triggers PI3Kδ/Akt and MEK/ERK pathways to induce IL-1 receptor antagonist in human monocytes. Carpintero Rakel,Brandt Karim J,Gruaz Lyssia,Molnarfi Nicolas,Lalive Patrice H,Burger Danielle Proceedings of the National Academy of Sciences of the United States of America Glatiramer acetate (GA), an immunomodulator used in multiple sclerosis (MS) therapy, induces the production of secreted IL-1 receptor antagonist (sIL-1Ra), a natural inhibitor of IL-1β, in human monocytes, and in turn enhances sIL-1Ra circulating levels in MS patients. GA is a mixture of peptides with random Glu, Lys, Ala, and Tyr sequences of high polarity and hydrophilic nature that is unlikely to cross the blood-brain barrier. In contrast, sIL-1Ra crosses the blood-brain barrier and, in turn, may mediate GA anti-inflammatory activities within the CNS by counteracting IL-1β activities. Here we identify intracellular signaling pathways induced by GA that control sIL-1Ra expression in human monocytes. By using kinase knockdown and specific inhibitors, we demonstrate that GA induces sIL-1Ra production via the activation of PI3Kδ, Akt, MEK1/2, and ERK1/2, demonstrating that both PI3Kδ/Akt and MEK/ERK pathways rule sIL-1Ra expression in human monocytes. The pathways act in parallel upstream glycogen synthase kinase-3α/β (GSK3α/β), the knockdown of which enhances sIL-1Ra production. Together, our findings demonstrate the existence of signal transduction triggered by GA, further highlighting the mechanisms of action of this drug in MS. 10.1073/pnas.1009443107
    Immunotherapy: PI3Kδ inhibition lifts the breaks on antitumour immunity. Killock David Nature reviews. Clinical oncology 10.1038/nrclinonc.2014.112
    Anticancer drugs: horizons broaden for PI3Kδ inhibitors. Kingwell Katie Nature reviews. Drug discovery 10.1038/nrd4399
    Inactivation of PI3Kδ induces vascular injury and promotes aneurysm development by upregulating the AP-1/MMP-12 pathway in macrophages. Zheng Lingyun,Xing Liying,Zeng Cuiling,Wu Teng,Gui Yali,Li Weidong,Lan Tian,Yang Yongxia,Gu Quliang,Qi Cuiling,Zhang Qianqian,Tang Futian,He Xiaodong,Wang Lijing Arteriosclerosis, thrombosis, and vascular biology OBJECTIVE:An aneurysm is an inflammatory vascular condition. Phosphatidylinositol 3-kinases δ is highly expressed in leukocytes, and play a key role in innate immunity. However, the link between phosphatidylinositol 3-kinases δ and aneurysm development has not yet been elucidated. APPROACH AND RESULTS:Carotid ligation unexpectedly induced characteristic aneurysm formation beneath the ligation point in p110δ(D910A/D910A) mice (n=25; P<0.001 versus wild-type). Besides, p110δ inactivation exacerbated CaCl2-induced abdominal aortic aneurysms development. A reverse transcription polymerase chain reaction microarray revealed significant extracellular matrix components degradation and matrix metalloproteinases (MMPs) upregulation in the abdominal aorta of p110δ(D910A/D910A) mice. Similarly, the expression of both collagen I and IV was significantly decreased (n=10; P<0.05 versus wild-type) in carotid artery. Western blot assay confirmed that MMP-12 was significantly upregulated in arteries of p110δ(D910A/D910A) mice (n=10; P<0.01 versus wild-type). In vitro, p110δ inactivation marked increase peritoneal macrophages recruitment and synergistically enhance tumor necrosis factor-α-induced recruitment. A specific phosphatidylinositol 3-kinases δ inhibitor (IC87114) or genetic p110δ inactivation upregulated MMP-12 expression and c-Jun phosphorylation (n=6; P<0.05 versus wild-type macrophages). IC87114 also increased activator protein-1 DNA-binding activity (n=6; P<0.001 versus control) and enhanced the effect of tumor necrosis factor-α on activator protein-1-binding activity (n=5; P<0.01 versus tumor necrosis factor-α treatment groups). Knockdown of c-Jun suppressed the effect of the IC87114 and tumor necrosis factor-α on MMP-12 mRNA expression (n=5 in each group; P<0.01 versus scrRNA treatment groups). CONCLUSIONS:Our findings demonstrate that p110δ inactivation leads to extracellular matrix degradation in vessels and promotes aneurysm development by inducing macrophages migration and upregulating the activator protein-1/MMP-12 pathway in macrophages. 10.1161/ATVBAHA.114.304365
    Phenotypic heterogeneity in IGHV-mutated CLL patients has prognostic impact and identifies a subset with increased sensitivity to BTK and PI3Kδ inhibition. Pepper C,Buggins A G S,Jones C H,Walsby E J,Forconi F,Pratt G,Devereux S,Stevenson F K,Fegan C Leukemia 10.1038/leu.2014.308
    The PI3Kδ inhibitor idelalisib suppresses liver and lung cellular respiration. Hammadi Suleiman Al,Almarzooqi Saeeda,Abdul-Kader Hidaya Mohammed,Saraswathiamma Dhanya,Souid Abdul-Kader International journal of physiology, pathophysiology and pharmacology Idelalisib (an inhibitor of phosphatidylinositol-3-kinase-delta) is approved for treatment of B-cell malignancies, with a Boxed Warning concerning potentially fatal hepatic, lung, and intestinal toxicities. The mechanisms of these tissue-specific adverse events have yet to be elucidated. This in vitro study investigated whether these effects could be attributed, at least in part, to altered cellular bioenergetics. A phosphorescence analyzer was used to measure cellular mitochondrial O2 consumption (kc , µM O2 min(-1) mg(-1)) in C57BL/6 mouse organs in the presence of 10 µM idelalisib or dimethyl-sulfoxide. Idelalisib significantly reduced the rate of cellular respiration in liver and lung fragments by 20% and 27%, respectively. Respiration in intestinal, thymic, and kidney fragments was unaffected. Idelalisib did not alter respiratory chain activities in mitochondria isolated from the liver and did not induce hepatocyte death. Thus, the drug mildly lowers liver and lung cellular respiration, an effect that may contribute to toxicities observed in these organs.
    PI3Kδ inhibition hits a sensitive spot in B cell malignancies. Vanhaesebroeck Bart,Khwaja Asim Cancer cell A PI3Kδ-selective inhibitor shows impressive clinical activity in chronic lymphocytic leukemia and indolent B cell non-Hodgkin's lymphomas. In these malignancies, the PI3K pathway is not mutationally activated as in many other cancers, but it is important for mediating supportive cues from the cancer microenvironment and the B cell antigen receptor. 10.1016/j.ccr.2014.02.012
    MT1-MMP regulates the PI3Kδ·Mi-2/NuRD-dependent control of macrophage immune function. Shimizu-Hirota Ryoko,Xiong Wanfen,Baxter B Timothy,Kunkel Steven L,Maillard Ivan,Chen Xiao-Wei,Sabeh Farideh,Liu Rui,Li Xiao-Yan,Weiss Stephen J Genes & development Macrophages play critical roles in events ranging from host defense to obesity and cancer, where they infiltrate affected tissues and orchestrate immune responses in tandem with the remodeling of the extracellular matrix (ECM). Despite the dual roles played by macrophages in inflammation, the functions of macrophage-derived proteinases are typically relegated to tissue-invasive or -degradative events. Here we report that the membrane-tethered matrix metalloenzyme MT1-MMP not only serves as an ECM-directed proteinase, but unexpectedly controls inflammatory gene responses wherein MT1-MMP(-/-) macrophages mount exaggerated chemokine and cytokine responses to immune stimuli both in vitro and in vivo. MT1-MMP modulates inflammatory responses in a protease-independent fashion in tandem with its trafficking to the nuclear compartment, where it triggers the expression and activation of a phosphoinositide 3-kinase δ (PI3Kδ)/Akt/GSK3β signaling cascade. In turn, MT1-MMP-dependent PI3Kδ activation regulates the immunoregulatory Mi-2/NuRD nucleosome remodeling complex that is responsible for controlling macrophage immune response. These findings identify a novel role for nuclear MT1-MMP as a previously unsuspected transactivator of signaling networks central to macrophage immune responses. 10.1101/gad.178749.111
    Correction to Evolution of a Novel, Orally Bioavailable Series of PI3Kδ Inhibitors from an Inhaled Lead for the Treatment of Respiratory Disease. Amour Augustin,Barton Nick,Cooper Anthony W J,Inglis Graham,Jamieson Craig,Luscombe Christopher N,Morrell Josie,Peace Simon,Perez David,Rowland Paul,Tame Christopher J,Uddin Sorif,Vitulli Giovanni,Wellaway Natalie Journal of medicinal chemistry 10.1021/acs.jmedchem.6b01461
    Discovery of (R)-8-(1-(3,5-difluorophenylamino)ethyl)-N,N-dimethyl-2-morpholino-4-oxo-4H-chromene-6-carboxamide (AZD8186): a potent and selective inhibitor of PI3Kβ and PI3Kδ for the treatment of PTEN-deficient cancers. Barlaam Bernard,Cosulich Sabina,Degorce Sébastien,Fitzek Martina,Green Stephen,Hancox Urs,Lambert-van der Brempt Christine,Lohmann Jean-Jacques,Maudet Mickaël,Morgentin Rémy,Pasquet Marie-Jeanne,Péru Aurélien,Plé Patrick,Saleh Twana,Vautier Michel,Walker Mike,Ward Lara,Warin Nicolas Journal of medicinal chemistry Several studies have highlighted the dependency of PTEN deficient tumors to PI3Kβ activity and specific inhibition of PI3Kδ has been shown activity against human B-cell cancers. We describe the discovery and optimization of a series of 8-(1-anilino)ethyl)-2-morpholino-4-oxo-4H-chromene-6-carboxamides as PI3Kβ/δ inhibitors, which led to the discovery of the clinical candidate 13, also known as AZD8186. On the basis of the lower lipophilicity of the chromen-4-one core compared to the previously utilized pyrido[1,2-a]pyrimid-4-one core, this series of compounds displayed high metabolic stability and suitable physical properties for oral administration. Compound 13 showed profound pharmacodynamic modulation of p-Akt in PTEN-deficient PC3 prostate tumor bearing mice after oral administration and showed complete inhibition of tumor growth in the mouse PTEN-deficient PC3 prostate tumor xenograft model. 13 was selected as a clinical candidate for treatment of PTEN-deficient cancers and has recently entered phase I clinical trials. 10.1021/jm501629p
    Discovery and in vivo evaluation of (S)-N-(1-(7-fluoro-2-(pyridin-2-yl)quinolin-3-yl)ethyl)-9H-purin-6-amine (AMG319) and related PI3Kδ inhibitors for inflammation and autoimmune disease. Cushing Timothy D,Hao Xiaolin,Shin Youngsook,Andrews Kristin,Brown Matthew,Cardozo Mario,Chen Yi,Duquette Jason,Fisher Ben,Gonzalez-Lopez de Turiso Felix,He Xiao,Henne Kirk R,Hu Yi-Ling,Hungate Randall,Johnson Michael G,Kelly Ron C,Lucas Brian,McCarter John D,McGee Lawrence R,Medina Julio C,San Miguel Tisha,Mohn Deanna,Pattaropong Vatee,Pettus Liping H,Reichelt Andreas,Rzasa Robert M,Seganish Jennifer,Tasker Andrew S,Wahl Robert C,Wannberg Sharon,Whittington Douglas A,Whoriskey John,Yu Gang,Zalameda Leeanne,Zhang Dawei,Metz Daniela P Journal of medicinal chemistry The development and optimization of a series of quinolinylpurines as potent and selective PI3Kδ kinase inhibitors with excellent physicochemical properties are described. This medicinal chemistry effort led to the identification of 1 (AMG319), a compound with an IC50 of 16 nM in a human whole blood assay (HWB), excellent selectivity over a large panel of protein kinases, and a high level of in vivo efficacy as measured by two rodent disease models of inflammation. 10.1021/jm501624r
    Targeting PI3Kδ: One man's meat is another man's poison. Prchal-Murphy Michaela,Putz Eva Maria,Freissmuth Michael,Sexl Veronika,Zebedin-Brandl Eva Oncoimmunology We have recently uncovered the indispensable role of phosphoinositide-3-kinase δ (PI3Kδ) at different stages of the canonical killing pathway of cytotoxic T lymphocytes (CTLs). The interception of PI3Kδ-conveyed signals has been considered a valuable therapeutic strategy in oncology. However, our observations predict that the benefits of this approach may be limited by a trade-off between direct anticancer effects and an impaired ability of CTLs and NK cells to attack tumor cells. 10.4161/onci.22272
    Conformational disruption of PI3Kδ regulation by immunodeficiency mutations in and . Dornan Gillian L,Siempelkamp Braden D,Jenkins Meredith L,Vadas Oscar,Lucas Carrie L,Burke John E Proceedings of the National Academy of Sciences of the United States of America Activated PI3K Delta Syndrome (APDS) is a primary immunodeficiency disease caused by activating mutations in either the leukocyte-restricted p110δ catalytic () subunit or the ubiquitously expressed p85α regulatory () subunit of class IA phosphoinositide 3-kinases (PI3Ks). There are two classes of APDS: APDS1 that arises from p110δ mutations that are analogous to oncogenic mutations found in the broadly expressed p110α subunit and APDS2 that occurs from a splice mutation resulting in p85α with a central deletion (Δ434-475). As p85 regulatory subunits associate with and inhibit all class IA catalytic subunits, APDS2 mutations are expected to similarly activate p110α, β, and δ, yet APDS2 largely phenocopies APDS1 without dramatic effects outside the immune system. We have examined the molecular mechanism of activation of both classes of APDS mutations using a combination of biochemical assays and hydrogen-deuterium exchange mass spectrometry. Intriguingly, we find that an APDS2 mutation in p85α leads to substantial basal activation of p110δ (>300-fold) and disrupts inhibitory interactions from the nSH2, iSH2, and cSH2 domains of p85, whereas p110α is only minimally basally activated (∼2-fold) when associated with mutated p85α. APDS1 mutations in p110δ (N334K, E525K, E1021K) mimic the activation mechanisms previously discovered for oncogenic mutations in p110α. All APDS mutations were potently inhibited by the Food and Drug Administration-approved p110δ inhibitor idelalisib. Our results define the molecular basis of how and mutations result in APDS and reveal a potential path to treatment for all APDS patients. 10.1073/pnas.1617244114
    Novel PIK3CD mutations affecting N-terminal residues of p110δ cause activated PI3Kδ syndrome (APDS) in humans. Takeda Andrew J,Zhang Yu,Dornan Gillian L,Siempelkamp Braden D,Jenkins Meredith L,Matthews Helen F,McElwee Joshua J,Bi Weimin,Seeborg Filiz O,Su Helen C,Burke John E,Lucas Carrie L The Journal of allergy and clinical immunology 10.1016/j.jaci.2017.03.026
    Umbralisib Inhibits PI3Kδ with Less Toxicity Than Previous Inhibitors. Cancer discovery Umbralisib is well tolerated and has activity against relapsed or refractory hematologic cancers. 10.1158/2159-8290.CD-RW2018-036
    PI3Kδ inhibition by idelalisib in patients with relapsed indolent lymphoma. Gopal Ajay K,Kahl Brad S,de Vos Sven,Wagner-Johnston Nina D,Schuster Stephen J,Jurczak Wojciech J,Flinn Ian W,Flowers Christopher R,Martin Peter,Viardot Andreas,Blum Kristie A,Goy Andre H,Davies Andrew J,Zinzani Pier Luigi,Dreyling Martin,Johnson Dave,Miller Langdon L,Holes Leanne,Li Daniel,Dansey Roger D,Godfrey Wayne R,Salles Gilles A The New England journal of medicine BACKGROUND:Phosphatidylinositol-3-kinase delta (PI3Kδ) mediates B-cell receptor signaling and microenvironmental support signals that promote the growth and survival of malignant B lymphocytes. In a phase 1 study, idelalisib, an orally active selective PI3Kδ inhibitor, showed antitumor activity in patients with previously treated indolent non-Hodgkin's lymphomas. METHODS:In this single-group, open-label, phase 2 study, 125 patients with indolent non-Hodgkin's lymphomas who had not had a response to rituximab and an alkylating agent or had had a relapse within 6 months after receipt of those therapies were administered idelalisib, 150 mg twice daily, until the disease progressed or the patient withdrew from the study. The primary end point was the overall rate of response; secondary end points included the duration of response, progression-free survival, and safety. RESULTS:The median age of the patients was 64 years (range, 33 to 87); patients had received a median of four prior therapies (range, 2 to 12). Subtypes of indolent non-Hodgkin's lymphoma included follicular lymphoma (72 patients), small lymphocytic lymphoma (28), marginal-zone lymphoma (15), and lymphoplasmacytic lymphoma with or without Waldenström's macroglobulinemia (10). The response rate was 57% (71 of 125 patients), with 6% meeting the criteria for a complete response. The median time to a response was 1.9 months, the median duration of response was 12.5 months, and the median progression-free survival was 11 months. Similar response rates were observed across all subtypes of indolent non-Hodgkin's lymphoma, though the numbers were small for some categories. The most common adverse events of grade 3 or higher were neutropenia (in 27% of the patients), elevations in aminotransferase levels (in 13%), diarrhea (in 13%), and pneumonia (in 7%). CONCLUSIONS:In this single-group study, idelalisib showed antitumor activity with an acceptable safety profile in patients with indolent non-Hodgkin's lymphoma who had received extensive prior treatment. (Funded by Gilead Sciences and others; ClinicalTrials.gov number, NCT01282424.). 10.1056/NEJMoa1314583
    Expression of PI3K Signaling Associated with T Cells in Psoriasis Is Inhibited by Seletalisib, a PI3Kδ Inhibitor, and Is Required for Functional Activity. Yager Nicole,Haddadeen Ciara,Powell Mark,Payne Andrew,Allen Rodger,Healy Eugene The Journal of investigative dermatology 10.1016/j.jid.2017.12.028
    A Prospective Virtual Screening Study: Enriching Hit Rates and Designing Focus Libraries To Find Inhibitors of PI3Kδ and PI3Kγ. Damm-Ganamet Kelly L,Bembenek Scott D,Venable Jennifer W,Castro Glenda G,Mangelschots Lieve,Peeters Daniëlle C G,Mcallister Heather M,Edwards James P,Disepio Daniel,Mirzadegan Taraneh Journal of medicinal chemistry Here, we report a high-throughput virtual screening (HTVS) study using phosphoinositide 3-kinase (both PI3Kγ and PI3Kδ). Our initial HTVS results of the Janssen corporate database identified small focused libraries with hit rates at 50% inhibition showing a 50-fold increase over those from a HTS (high-throughput screen). Further, applying constraints based on "chemically intuitive" hydrogen bonds and/or positional requirements resulted in a substantial improvement in the hit rates (versus no constraints) and reduced docking time. While we find that docking scoring functions are not capable of providing a reliable relative ranking of a set of compounds, a prioritization of groups of compounds (e.g., low, medium, and high) does emerge, which allows for the chemistry efforts to be quickly focused on the most viable candidates. Thus, this illustrates that it is not always necessary to have a high correlation between a computational score and the experimental data to impact the drug discovery process. 10.1021/acs.jmedchem.5b01974
    Can umbralisib bring PI3Kδ out of the shadows? Barrientos Jacqueline C The Lancet. Oncology 10.1016/S1470-2045(18)30154-2
    A phase 1 study of the PI3Kδ inhibitor idelalisib in patients with relapsed/refractory mantle cell lymphoma (MCL). Kahl Brad S,Spurgeon Stephen E,Furman Richard R,Flinn Ian W,Coutre Steven E,Brown Jennifer R,Benson Don M,Byrd John C,Peterman Sissy,Cho Yoonjin,Yu Albert,Godfrey Wayne R,Wagner-Johnston Nina D Blood Idelalisib, an oral inhibitor of phosphatidylinositol-3-kinase δ (PI3Kδ), was evaluated in a 48-week phase 1 study (50-350 mg daily or twice daily) enrolling 40 patients with relapsed or refractory mantle cell lymphoma (MCL). Primary outcome was safety and dose-limiting toxicity (DLT). Secondary outcomes were pharmacokinetic parameters, pharmacodynamic effects, overall response rate (ORR), progression-free survival (PFS), and duration of response (DOR). Patients without DLT and no evidence of disease progression after 48 weeks enrolled in the extension study. Patients had median age of 69 years (range, 52-83) and received median of 4 prior therapies (1-14); 17 of 40 patients (43%) were refractory to their most recent treatment. Median duration of idelalisib treatment was 3.5 months (range, 0.7-30.7), with 6 (15%) continuing extension treatment. Common grade ≥3 adverse events (AEs) included (total%/grade ≥3%) diarrhea (40/18), nausea (33/5), pyrexia (28/0), fatigue (25/3), rash (23/3), decreased appetite (20/15), upper respiratory infection (20/0), pneumonia (13/10), and alanine transaminase or aspartate transaminase elevations (60/20). ORR was 16 of 40 patients (40%), with CR in 2 of 40 patients (5%). Median DOR was 2.7 months, median PFS was 3.7 months, and 1-year PFS was 22%. These data provide proof of concept that targeting PI3Kδ is a viable strategy and worthy of additional study in MCL. This trial was registered at www.clinicaltrials.gov as #NCT00710528. 10.1182/blood-2013-11-537555
    PI3Kδ: Too much of a good thing. Kennedy Domenick E,Clark Marcus R Nature immunology 10.1038/s41590-018-0183-2
    Activated PI3Kδ syndrome type 2: Two patients, a novel mutation, and review of the literature. Olbrich Peter,Lorenz Myriam,Cura Daball Paola,Lucena José Manuel,Rensing-Ehl Anne,Sanchez Berta,Führer Marita,Camacho-Lovillo Marisol,Melon Marta,Schwarz Klaus,Neth Olaf,Speckmann Carsten Pediatric allergy and immunology : official publication of the European Society of Pediatric Allergy and Immunology BACKGROUND:Autosomal dominant gain-of-function mutations in PIK3R1 encoding for the regulatory subunit (p85α, p55α, and p50α) of Class IA phosphoinositide 3-kinase (PI3K) result in the activated PI3Kδ syndrome (APDS) type 2 characterized by childhood-onset combined immunodeficiency, lymphoproliferation, and immune dysregulation. To improve clinical awareness and understanding of these rare diseases, we reviewed all hitherto published cases with APDS type 1 and type 2 for their clinical and immunologic symptoms and added novel clinical, immunologic, and genetic findings of two patients with APDS type 2. METHODS:Clinical, immunologic, and genetic evaluation of two new patients with APDS2 was performed followed by the systematic collection of all available previously published data of patients with APDS1 and APDS2. RESULTS:Patients with APDS type 1 (n = 49) and type 2 (n = 15) showed an indistinguishable immunologic phenotype. Overlapping clinical features shared by APDS type 1 and type 2 were observed, but our review also revealed previously unnoticed clinical differences such as remarkably high incidence of microcephaly, poor growth/short stature in patients with APDS2. Clinical management and outcome were variable and included prophylactic antibiotics, immunosuppression, immunoglobulin substitution, and hematopoietic stem cell transplantation. CONCLUSIONS:A disease-specific registry collecting prospective and long-term follow-up data of patients with APDS, as currently set up by the European Society for Immunodeficiencies, are needed to better understand the natural history and to optimize treatment concepts and thereby improving the outcome of this heterogenous patient group. 10.1111/pai.12585
    Evolution of a Novel, Orally Bioavailable Series of PI3Kδ Inhibitors from an Inhaled Lead for the Treatment of Respiratory Disease. Amour Augustin,Barton Nick,Cooper Anthony W J,Inglis Graham,Jamieson Craig,Luscombe Christopher N,Morrell Josie,Peace Simon,Perez David,Rowland Paul,Tame Christopher J,Uddin Sorif,Vitulli Giovanni,Wellaway Natalie Journal of medicinal chemistry A four-step process of high-quality modeling of existing data, deconstruction, identification of replacement cores, and an innovative synthetic regrowth strategy led to the rapid discovery of a novel oral series of PI3Kδ inhibitors with promising selectivity and excellent in vivo characteristics. 10.1021/acs.jmedchem.6b00799
    Discovery of a Phosphoinositide 3-Kinase (PI3K) β/δ Inhibitor for the Treatment of Phosphatase and Tensin Homolog (PTEN) Deficient Tumors: Building PI3Kβ Potency in a PI3Kδ-Selective Template by Targeting Nonconserved Asp856. Perreault Stephane,Chandrasekhar Jayaraman,Cui Zhi-Hua,Evarts Jerry,Hao Jia,Kaplan Joshua A,Kashishian Adam,Keegan Kathleen S,Kenney Thomas,Koditek David,Lad Latesh,Lepist Eve-Irene,McGrath Mary E,Patel Leena,Phillips Bart,Therrien Joseph,Treiberg Jennifer,Yahiaoui Anella,Phillips Gary Journal of medicinal chemistry Phosphoinositide 3-kinase (PI3K) β signaling is required to sustain cancer cell growth in which the tumor suppressor phosphatase and tensin homolog (PTEN) has been deactivated. This manuscript describes the discovery, optimization, and in vivo evaluation of a novel series of PI3Kβ/δ inhibitors in which PI3Kβ potency was built in a PI3Kδ-selective template. This work led to the discovery of a highly selective PI3Kβ/δ inhibitor displaying excellent pharmacokinetic profile and efficacy in a human PTEN-deficient LNCaP prostate carcinoma xenograft tumor model. 10.1021/acs.jmedchem.6b01821
    Discovery of novel and highly selective PI3Kδ inhibitors based on the p110δ crystal structure. Jia Wen-Qing,Liu Ya-Ya,Feng Xiao-Yan,Xu Wei-Ren,Cheng Xian-Chao Journal of biomolecular structure & dynamics Communicated by Ramaswamy H. Sarma. 10.1080/07391102.2019.1635531
    Design and Synthesis of Soluble and Cell-Permeable PI3Kδ Inhibitors for Long-Acting Inhaled Administration. Perry Matthew W D,Björhall Karin,Bonn Britta,Carlsson Johan,Chen Yunhua,Eriksson Anders,Fredlund Linda,Hao Hai'e,Holden Neil S,Karabelas Kostas,Lindmark Helena,Liu Feifei,Pemberton Nils,Petersen Jens,Rodrigo Blomqvist Sandra,Smith Reed W,Svensson Tor,Terstiege Ina,Tyrchan Christian,Yang Wenzhen,Zhao Shuchun,Öster Linda Journal of medicinal chemistry PI3Kδ is a lipid kinase that is believed to be important in the migration and activation of cells of the immune system. Inhibition is hypothesized to provide a powerful yet selective immunomodulatory effect that may be beneficial for the treatment of conditions such as asthma or rheumatoid arthritis. In this work, we describe the identification of inhibitors based on a thiazolopyridone core structure and their subsequent optimization for inhalation. The initially identified compound (13) had good potency and isoform selectivity but was not suitable for inhalation. Addition of basic substituents to a region of the molecule pointing to solvent was tolerated (enzyme inhibition pIC > 9), and by careful manipulation of the pK and lipophilicity, we were able to discover compounds (20b, 20f) with good lung retention and cell potency that could be taken forward to in vivo studies where significant target engagement could be demonstrated. 10.1021/acs.jmedchem.7b00401
    Selectively Targeting the Kinome-Conserved Lysine of PI3Kδ as a General Approach to Covalent Kinase Inhibition. Dalton Samuel E,Dittus Lars,Thomas Daniel A,Convery Máire A,Nunes Joao,Bush Jacob T,Evans John P,Werner Thilo,Bantscheff Marcus,Murphy John A,Campos Sebastien Journal of the American Chemical Society Selective covalent inhibition of kinases by targeting poorly conserved cysteines has proven highly fruitful to date in the development of chemical probes and approved drugs. However, this approach is limited to ∼200 kinases possessing such a cysteine near the ATP-binding pocket. Herein, we report a novel approach to achieve selective, irreversible kinase inhibition, by targeting the conserved catalytic lysine residue. We have illustrated our approach by developing selective, covalent PI3Kδ inhibitors that exhibit nanomolar potency in cellular assays, and a duration of action >48 h in CD4+ T cells. Despite conservation of the lysine residue throughout the kinome, the lead compound shows high levels of selectivity over a selection of lipid and protein kinases in biochemical assays, as well as covalent binding to very few off-target proteins in live-cell proteomic studies. We anticipate this approach could offer a general strategy, as an alternative to targeting non-conserved cysteines, for the development of selective covalent kinase inhibitors. 10.1021/jacs.7b08979
    Enhanced AKT Phosphorylation of Circulating B Cells in Patients With Activated PI3Kδ Syndrome. Asano Takaki,Okada Satoshi,Tsumura Miyuki,Yeh Tzu-Wen,Mitsui-Sekinaka Kanako,Tsujita Yuki,Ichinose Youjiro,Shimada Akira,Hashimoto Kunio,Wada Taizo,Imai Kohsuke,Ohara Osamu,Morio Tomohiro,Nonoyama Shigeaki,Kobayashi Masao Frontiers in immunology Activated PI3Kδ syndrome (APDS) is a primary immunodeficiency characterized by recurrent respiratory tract infections, lymphoproliferation, and defective IgG production. Heterozygous mutations in , or , which are related to the hyperactive phosphoinositide 3-kinase (PI3K) signaling, were recently presented to cause APDS1 or APDS2 (APDSs), or APDS-like (APDS-L) disorder. In this study, we examined the AKT phosphorylation of peripheral blood lymphocytes and monocytes in patients with APDSs and APDS-L by using flow cytometry. CD19 B cells of peripheral blood in APDS2 patients showed the enhanced phosphorylation of AKT at Ser473 (pAKT) without any specific stimulation. The enhanced pAKT in CD19 B cells was normalized by the addition of a p110δ inhibitor. In contrast, CD3 T cells and CD14 monocytes did not show the enhanced pAKT in the absence of stimulation. These findings were similarly observed in patients with APDS1 and APDS-L. Among CD19 B cells, enhanced pAKT was prominently detected in CD10 immature B cells compared with CD10 mature B cells. Enhanced pAKT was not observed in B cells of healthy controls, patients with common variable immunodeficiency, and hyper IgM syndrome due to CD40L deficiency. These results suggest that the enhanced pAKT in circulating B cells may be useful for the discrimination of APDS1, APDS2, and APDS-L from other antibody deficiencies. 10.3389/fimmu.2018.00568
    Synergistic Targeting of the Regulatory and Catalytic Subunits of PI3Kδ in Mature B-cell Malignancies. Cooney Jeffrey D,Lin An-Ping,Jiang Daifeng,Wang Long,Suhasini Avvaru N,Myers Jamie,Qiu ZhiJun,Wölfler Albert,Sill Heinz,Aguiar Ricardo C T Clinical cancer research : an official journal of the American Association for Cancer Research Aberrant activation of the B-cell receptor (BCR) is implicated in the pathogenesis of mature B-cell tumors, a concept validated in part by the clinical success of inhibitors of the BCR-related kinases BTK (Bruton's tyrosine kinase) and PI3Kδ. These inhibitors have limitations, including the paucity of complete responses, acquired resistance, and toxicity. Here, we examined the mechanism by which the cyclic-AMP/PDE4 signaling axis suppresses PI3K, toward identifying a novel mechanism-based combinatorial strategy to attack BCR-dependency in mature B-cell malignancies. We used and diffuse large B-cell lymphoma (DLBCL) cell lines and primary chronic lymphocytic leukemia (CLL) samples to preclinically evaluate the effects of the combination of the FDA-approved phosphodiesterase 4 (PDE4) inhibitor roflumilast and idelalisib on cell survival and tumor growth. Genetic models of gain- and loss-of-function were used to map multiple signaling intermediaries downstream of the BCR. Roflumilast elevates the intracellular levels of cyclic-AMP and synergizes with idelalisib in suppressing tumor growth and PI3K activity. Mechanistically, we show that roflumilast suppresses PI3K by inhibiting BCR-mediated activation of the P85 regulatory subunit, distinguishing itself from idelalisib, an ATP-competitive inhibitor of the catalytic P110 subunit. Using genetic models, we linked the PDE4-regulated modulation of P85 activation to the oncogenic kinase SYK. These data demonstrate that roflumilast and idelalisib suppress PI3K by distinct mechanisms, explaining the basis for their synergism, and suggest that the repurposing of PDE4 inhibitors to treat BCR-dependent malignancies is warranted. . 10.1158/1078-0432.CCR-17-2218
    PI3Kδ activates E2F1 synthesis in response to mRNA translation stress. Gnanasundram Sivakumar Vadivel,Pyndiah Slovénie,Daskalogianni Chrysoula,Armfield Kate,Nylander Karin,Wilson Joanna B,Fåhraeus Robin Nature communications The c-myc oncogene stimulates ribosomal biogenesis and protein synthesis to promote cellular growth. However, the pathway by which cells sense and restore dysfunctional mRNA translation and how this is linked to cell proliferation and growth is not known. We here show that mRNA translation stress in cis triggered by the gly-ala repeat sequence of Epstein-Barr virus (EBV)-encoded EBNA1, results in PI3Kδ-dependent induction of E2F1 mRNA translation with the consequent activation of c-Myc and cell proliferation. Treatment with a specific PI3Kδ inhibitor Idelalisib (CAL-101) suppresses E2F1 and c-Myc levels and causes cell death in EBNA1-induced B cell lymphomas. Suppression of PI3Kδ prevents E2F1 activation also in non-EBV-infected cells. These data illustrate an mRNA translation stress-response pathway for E2F1 activation that is exploited by EBV to promote cell growth and proliferation, offering new strategies to treat EBV-carrying cancers. 10.1038/s41467-017-02282-w
    PI3Kδ inhibition reduces TNF secretion and neuroinflammation in a mouse cerebral stroke model. Low Pei Ching,Manzanero Silvia,Mohannak Nika,Narayana Vinod K,Nguyen Tam H,Kvaskoff David,Brennan Faith H,Ruitenberg Marc J,Gelderblom Mathias,Magnus Tim,Kim Hyun Ah,Broughton Brad R S,Sobey Christopher G,Vanhaesebroeck Bart,Stow Jennifer L,Arumugam Thiruma V,Meunier Frédéric A Nature communications Stroke is a major cause of death worldwide and the leading cause of permanent disability. Although reperfusion is currently used as treatment, the restoration of blood flow following ischaemia elicits a profound inflammatory response mediated by proinflammatory cytokines such as tumour necrosis factor (TNF), exacerbating tissue damage and worsening the outcomes for stroke patients. Phosphoinositide 3-kinase delta (PI3Kδ) controls intracellular TNF trafficking in macrophages and therefore represents a prospective target to limit neuroinflammation. Here we show that PI3Kδ inhibition confers protection in ischaemia/reperfusion models of stroke. In vitro, restoration of glucose supply following an episode of glucose deprivation potentiates TNF secretion from primary microglia-an effect that is sensitive to PI3Kδ inhibition. In vivo, transient middle cerebral artery occlusion and reperfusion in kinase-dead PI3Kδ (p110δ(D910A/D910A)) or wild-type mice pre- or post-treated with the PI3Kδ inhibitor CAL-101, leads to reduced TNF levels, decreased leukocyte infiltration, reduced infarct size and improved functional outcome. These data identify PI3Kδ as a potential therapeutic target in ischaemic stroke. 10.1038/ncomms4450
    Free-Wilson Analysis of Comprehensive Data on Phosphoinositide-3-kinase (PI3K) Inhibitors Reveals Importance of -Methylation for PI3Kδ Activity. Barnes Lydia,Blaber Hollie,Brooks David T K,Byers Lewis,Buckley Daniel,Byron Zoe C,Chilvers Richard G,Cochrane Liam,Cooney Edward,Damian Heather A,Francis Luke,Fu He Daniel,Grace Jack M J,Green Harley J,Hogarth Edmund J P,Jusu Leyla,Killalea C Elizabeth,King Oliver,Lambert Joseph,Lee Zoe J,Lima Nuria S,Long Christina L,Mackinnon May-Li,Mahdy Shusha,Matthews-Wright Jolyon,Millward Makenzie J,Meehan Matthew F,Merrett Christopher,Morrison Lisa,Parke Hal R I,Payne Charlotte,Payne Lawrence,Pike Craig,Seal Alexander,Senior Aaron J,Smith Keenan M,Stanelyte Kamile,Stillibrand Joe,Szpara Rachel,Taday Freya F H,Threadgould Antony M,Trainor Rohan J,Waters Jordan,Williams Oliver,Wong Carrie K W,Wood Katherine,Barton Nick,Gruszka Anna,Henley Zoe,Rowedder James E,Cookson Rosa,Jones Katherine L,Nadin Alan,Smith Ian E,Macdonald Simon J F,Nortcliffe Andrew Journal of medicinal chemistry Phosphoinositide-3-kinase δ (PI3Kδ) is a critical regulator of cell growth and transformation and has been explored as a therapeutic target for a range of diseases. Through the exploration of the thienopyrimidine scaffold, we have identified a ligand-efficient methylation that leads to remarkable selectivity for PI3Kδ over the closely related isoforms. Interrogation through the Free-Wilson analysis highlights the innate selectivity the thienopyrimidine scaffold has for PI3Kδ and provides a predictive model for the activity against the PI3K isoforms. 10.1021/acs.jmedchem.9b01499
    PI3Kδ Regulates the Magnitude of CD8+ T Cell Responses after Challenge with Listeria monocytogenes. Pearce Verity Q,Bouabe Hicham,MacQueen Amy R,Carbonaro Valentina,Okkenhaug Klaus Journal of immunology (Baltimore, Md. : 1950) PI3Ks regulate diverse immune cell functions by transmitting intracellular signals from Ag, costimulatory receptors, and cytokine receptors to control cell division, differentiation, survival, and migration. In this study, we report the effect of inhibiting the p110δ subunit of PI3Kδ on CD8(+) T cell responses to infection with the intracellular bacteria Listeria monocytogenes. A strong dependency on PI3Kδ for IFN-γ production by CD8(+) T cells in vitro was not recapitulated after Listeria infection in vivo. Inactivation of PI3Kδ resulted in enhanced bacterial elimination by the innate immune system. However, the magnitudes of the primary and secondary CD8 +: T cell responses were reduced. Moreover, PI3Kδ activity was required for CD8(+) T cells to provide help to other responding CD8(+) cells. These findings identify PI3Kδ as a key regulator of CD8(+) T cell responses that integrates extrinsic cues, including those from other responding cells, to determine the collective behavior of CD8(+) T cell populations responding to infection. 10.4049/jimmunol.1501227
    Simultaneous Inhibition of PI3Kδ and PI3Kα Induces ABC-DLBCL Regression by Blocking BCR-Dependent and -Independent Activation of NF-κB and AKT. Paul Juliane,Soujon Maurice,Wengner Antje M,Zitzmann-Kolbe Sabine,Sturz Andrea,Haike Katja,Keng Magdalene Koh Hui,Tan Sze Huey,Lange Martin,Tan Soo Yong,Mumberg Dominik,Lim Soon Thye,Ziegelbauer Karl,Liu Ningshu Cancer cell Compared with follicular lymphoma, high PI3Kα expression was more prevalent in diffuse large B cell lymphoma (DLBCL), although both tumor types expressed substantial PI3Kδ. Simultaneous inhibition of PI3Kα and PI3Kδ dramatically enhanced the anti-tumor profile in ABC-DLBCL models compared with selective inhibition of PI3Kδ, PI3Kα, or BTK. The anti-tumor activity was associated with suppression of p-AKT and a mechanism of blocking nuclear factor-κB activation driven by CD79, CARD11, TNFAIP3, or MYD88. Inhibition of PI3Kα/δ resulted in tumor regression in an ibrutinib-resistant CD79B/MYD88 patient-derived ABC-DLBCL model. Furthermore, rebound activation of BTK and AKT was identified as a mechanism limiting CD79B-ABC-DLBCL to show a robust response to PI3K and BTK inhibitor monotherapies. A combination of ibrutinib with the PI3Kα/δ inhibitor copanlisib produced a sustained complete response in vivo in CD79B/MYD88 ABC-DLBCL models. 10.1016/j.ccell.2016.12.003
    Hyperactivated PI3Kδ promotes self and commensal reactivity at the expense of optimal humoral immunity. Preite Silvia,Cannons Jennifer L,Radtke Andrea J,Vujkovic-Cvijin Ivan,Gomez-Rodriguez Julio,Volpi Stefano,Huang Bonnie,Cheng Jun,Collins Nicholas,Reilley Julie,Handon Robin,Dobbs Kerry,Huq Lutfi,Raman Indu,Zhu Chengsong,Li Quan-Zhen,Li Ming O,Pittaluga Stefania,Uzel Gulbu,Notarangelo Luigi D,Belkaid Yasmine,Germain Ronald N,Schwartzberg Pamela L Nature immunology Gain-of-function mutations in the gene encoding the phosphatidylinositol-3-OH kinase catalytic subunit p110δ (PI3Kδ) result in a human primary immunodeficiency characterized by lymphoproliferation, respiratory infections and inefficient responses to vaccines. However, what promotes these immunological disturbances at the cellular and molecular level remains unknown. We generated a mouse model that recapitulated major features of this disease and used this model and patient samples to probe how hyperactive PI3Kδ fosters aberrant humoral immunity. We found that mutant PI3Kδ led to co-stimulatory receptor ICOS-independent increases in the abundance of follicular helper T cells (T cells) and germinal-center (GC) B cells, disorganized GCs and poor class-switched antigen-specific responses to immunization, associated with altered regulation of the transcription factor FOXO1 and pro-apoptotic and anti-apoptotic members of the BCL-2 family. Notably, aberrant responses were accompanied by increased reactivity to gut bacteria and a broad increase in autoantibodies that were dependent on stimulation by commensal microbes. Our findings suggest that proper regulation of PI3Kδ is critical for ensuring optimal host-protective humoral immunity despite tonic stimulation from the commensal microbiome. 10.1038/s41590-018-0182-3
    Characterization of Novel PI3Kδ Inhibitors as Potential Therapeutics for SLE and Lupus Nephritis in Pre-Clinical Studies. Haselmayer Philipp,Camps Montserrat,Muzerelle Mathilde,El Bawab Samer,Waltzinger Caroline,Bruns Lisa,Abla Nada,Polokoff Mark A,Jond-Necand Carole,Gaudet Marilène,Benoit Audrey,Bertschy Meier Dominique,Martin Catherine,Gretener Denise,Lombardi Maria Stella,Grenningloh Roland,Ladel Christoph,Petersen Jørgen Søberg,Gaillard Pascale,Ji Hong Frontiers in immunology SLE is a complex autoimmune inflammatory disease characterized by pathogenic autoantibody production as a consequence of uncontrolled T-B cell activity and immune-complex deposition in various organs, including kidney, leading to tissue damage and function loss. There is a high unmet need for better treatment options other than corticosteroids and immunosuppressants. Phosphoinositol-3 kinase δ (PI3Kδ) is a promising target in this respect as it is essential in mediating B- and T-cell function in mouse and human. We report the identification of selective PI3Kδ inhibitors that blocked B-, T-, and plasmacytoid dendritic cell activities in human peripheral blood and in primary cell co-cultures (BioMAP(®)) without detecting signs of undesired toxicity. In an IFNα-accelerated mouse SLE model, our PI3Kδ inhibitors blocked nephritis development, whether administered at the onset of autoantibody appearance or the onset of proteinuria. Disease amelioration correlated with normalized immune cell numbers in the spleen, reduced immune-complex deposition as well as reduced inflammation, fibrosis, and tissue damage in the kidney. Improvements were similar to those achieved with a frequently prescribed drug for lupus nephritis, the potent immunosuppressant mycophenolate mofetil. Finally, we established a pharmacodynamics/pharmacokinetic/efficacy model that revealed that a sustained PI3Kδ inhibition of 50% is sufficient to achieve full efficacy in our disease model. These data demonstrate the therapeutic potential of PI3Kδ inhibitors in SLE and lupus nephritis. 10.3389/fimmu.2014.00233
    PI3Kδ hyper-activation promotes development of B cells that exacerbate Streptococcus pneumoniae infection in an antibody-independent manner. Stark Anne-Katrien,Chandra Anita,Chakraborty Krishnendu,Alam Rafeah,Carbonaro Valentina,Clark Jonathan,Sriskantharajah Srividya,Bradley Glyn,Richter Alex G,Banham-Hall Edward,Clatworthy Menna R,Nejentsev Sergey,Hamblin J Nicole,Hessel Edith M,Condliffe Alison M,Okkenhaug Klaus Nature communications Streptococcus pneumoniae is a major cause of pneumonia and a leading cause of death world-wide. Antibody-mediated immune responses can confer protection against repeated exposure to S. pneumoniae, yet vaccines offer only partial protection. Patients with Activated PI3Kδ Syndrome (APDS) are highly susceptible to S. pneumoniae. We generated a conditional knock-in mouse model of this disease and identify a CD19B220 B cell subset that is induced by PI3Kδ signaling, resides in the lungs, and is correlated with increased susceptibility to S. pneumoniae during early phases of infection via an antibody-independent mechanism. We show that an inhaled PI3Kδ inhibitor improves survival rates following S. pneumoniae infection in wild-type mice and in mice with activated PI3Kδ. These results suggest that a subset of B cells in the lung can promote the severity of S. pneumoniae infection, representing a potential therapeutic target. 10.1038/s41467-018-05674-8
    Identification of highly potent and selective PI3Kδ inhibitors. Marcoux David,Qin Lan-Ying,Ruan Zheming,Shi Qing,Ruan Qian,Weigelt Carolyn,Qiu Hongchen,Schieven Gary,Hynes John,Bhide Rajeev,Poss Michael,Tino Joseph Bioorganic & medicinal chemistry letters Selective PI3Kδ inhibitors have recently been hypothesized to be appropriate immunosuppressive agents for the treatment of immunological disorders such as rheumatoid arthritis. However, few reports have highlighted molecules that are highly selective for PI3Kδ over the other PI3K isoforms. In this letter, isoform and kinome selective PI3Kδ inhibitors are presented. The Structural Activity Relationship leading to such molecules is outlined. 10.1016/j.bmcl.2017.01.077
    Differential PI3Kδ Signaling in CD4 T-cell Subsets Enables Selective Targeting of T Regulatory Cells to Enhance Cancer Immunotherapy. Ahmad Shamim,Abu-Eid Rasha,Shrimali Rajeev,Webb Mason,Verma Vivek,Doroodchi Atbin,Berrong Zuzana,Samara Raed,Rodriguez Paulo C,Mkrtichyan Mikayel,Khleif Samir N Cancer research To modulate T-cell function for cancer therapy, one challenge is to selectively attenuate regulatory but not conventional CD4 T-cell subsets [regulatory T cell (Treg) and conventional T cell (Tconv)]. In this study, we show how a functional dichotomy in Class IA PI3K isoforms in these two subsets of CD4 T cells can be exploited to target Treg while leaving Tconv intact. Studies employing isoform-specific PI3K inhibitors and a PI3Kδ-deficient mouse strain revealed that PI3Kα and PI3Kβ were functionally redundant with PI3Kδ in Tconv. Conversely, PI3Kδ was functionally critical in Treg, acting there to control T-cell receptor signaling, cell proliferation, and survival. Notably, in a murine model of lung cancer, coadministration of a PI3Kδ-specific inhibitor with a tumor-specific vaccine decreased numbers of suppressive Treg and increased numbers of vaccine-induced CD8 T cells within the tumor microenvironment, eliciting potent antitumor efficacy. Overall, our results offer a mechanistic rationale to employ PI3Kδ inhibitors to selectively target Treg and improve cancer immunotherapy. . 10.1158/0008-5472.CAN-16-1839
    Inhibition of PI3Kδ reduces kidney infiltration by macrophages and ameliorates systemic lupus in the mouse. Suárez-Fueyo Abel,Rojas José M,Cariaga Ariel E,García Esther,Steiner Bart H,Barber Domingo F,Puri Kamal D,Carrera Ana C Journal of immunology (Baltimore, Md. : 1950) Systemic lupus erythematosus (SLE) is a human chronic inflammatory disease generated and maintained throughout life by autoreactive T and B cells. Class I phosphoinositide 3-kinases (PI3K) are heterodimers composed of a regulatory and a catalytic subunit that catalyze phosphoinositide-3,4,5-P3 formation and regulate cell survival, migration, and division. Activity of the PI3Kδ isoform is enhanced in human SLE patient PBLs. In this study, we analyzed the effect of inhibiting PI3Kδ in MRL/lpr mice, a model of human SLE. We found that PI3Kδ inhibition ameliorated lupus progression. Treatment of these mice with a PI3Kδ inhibitor reduced the excessive numbers of CD4(+) effector/memory cells and B cells. In addition, this treatment reduced serum TNF-α levels and the number of macrophages infiltrating the kidney. Expression of inactive PI3Kδ, but not deletion of the other hematopoietic isoform PI3Kγ, reduced the ability of macrophages to cross the basement membrane, a process required to infiltrate the kidney, explaining MRL/lpr mice improvement by pharmacologic inhibition of PI3Kδ. The observations that p110δ inhibitor prolonged mouse life span, reduced disease symptoms, and showed no obvious secondary effects indicates that PI3Kδ is a promising target for SLE. 10.4049/jimmunol.1400350
    [Mechanisms of cytoskeleton and PI3Kδ-RhoA in fine particulate matter deteriorating phagocytosis defect of alveolar macrophage in mice with chronic obstructive pulmonary disease]. Xia Q,Hu S T,Zeng X L,Bao H R,Liu X J Zhonghua yi xue za zhi To explore the mechanism of cytoskeleton and PI3Kδ-RhoA in fine particulate matter deteriorating phagocytosis defect of alveolar macrophage (AM) in chronic obstructive pulmonary disease (COPD) mice. Forty mice were randomly divided into four groups: health control group, COPD group, health PM2.5 group, COPD PM2.5 group and with ten in each group. A mouse model of COPD was established by cigarette smoke exposure, and health PM2.5 group and COPD PM2.5 group mice were given PM2.5 (588 μg/m(3)) aerosol inhalation for 90 days. AM were isolated from lung tissue by discontinuous density gradient centrifugation. Mean fluorescence intensity (MFI) and the percent of alveolar macrophage engulfing flurescein isothiocyanate-labeled Escherichia coli (FITC-.) AM (AM%) were detected by flow cytometry. The mRNA and protein expression were measured by real time polymerase chain reaction (RT-PCR) and Western blot. The activity of RhoA was measured by GTPase linked immunosorbent assay (G-LISA) Kit. Cytoskeleton was observed by laser scanning confocal microscopy. The MFI and the AM% in COPD group [4 512±517, (32.19±4.57)%] and health PM2.5 group [7 631±585, (50.78±4.58)%] were significantly lower than those in health control group [9 857±1 042, (68.53±2.88)%], while those in COPD PM2.5 group [3 121±393, (21.90±2.58)%] were lower than those in COPD group (all <0.01). The mRNA and protein of PI3Kδ in COPD group (3.41±0.54, 0.84±0.08)and health PM2.5 group (1.52±0.35, 0.71±0.11) were higher than those in health control group (1.00±0.00, 0.57±0.07) (all <0.05), and in COPD PM2.5 group (5.53±0.42, 1.17±0.25), the above parameters were remarkably increased as compared to those in COPD group (all <0.01). The mRNA, protein and activity of RhoA in COPD group (0.70±0.07, 0.41±0.10, 0.70±0.06) and health PM2.5 group (0.84±0.06, 0.46±0.11, 0.87±0.07) were lower than those in health control group (1.00±0.00, 0.56±0.09, 1.19±0.09) (all <0.05), and above parameters of COPD PM2.5 group (0.42±0.05, 0.31±0.06, 0.44±0.04) were significantly lower than COPD group (all <0.01). Cytoskeleton of AM: long and dense filopodia and membrane fold could been seen clearly around the AM of health control group; in COPD group and health PM2.5 group, short and sparse filopodia and slightly deformed AM can been seen. Filopodia remarkably decreased and rigid cells with impaired capacity of engulfing FITC-. can be generally observed in COPD PM2.5 group. Negative correlations were existed between PI3Kδ mRNA, protein and RhoA mRNA, protein, activity in all groups (all <0.01). Negative correlations were existed between PI3Kδ mRNA, protein and MFI, and positive correlations were existed between RhoA mRNA, protein, activity and MFI in all groups (all <0.05). Fine particulate matter (PM2.5) can deteriorate the phagocytosis of AM from COPD mice through over activating PI3Kδ and inhibiting the activity of RhoA then causing cytoskeleton abnormal rearrangement. 10.3760/cma.j.issn.0376-2491.2017.24.011
    Discovery and biological evaluation of novel pyrazolopyridine derivatives as potent and orally available PI3Kδ inhibitors. Hamajima Toshihiro,Takahashi Fumie,Kato Koji,Mukoyoshi Koichiro,Yoshihara Kousei,Yamaki Susumu,Sugano Yukihito,Moritomo Ayako,Yamagami Kaoru,Yokoo Koji,Fukahori Hidehiko Bioorganic & medicinal chemistry Phosphatidylinositol-3-kinase (PI3K)δ inhibition is one of the most attractive approaches to the treatment of autoimmune diseases and leukocyte malignancies. Through the exploration of pyrazolopyridine derivatives as potential PI3Kδ inhibitors, compound 12a was identified as a potent PI3Kδ inhibitor but suffered from poor oral exposure in mice. With a modified amide linkage group, compound 15a was developed as an orally available PI3Kδ inhibitor with reduced selectivity against other PI3Ks. To improve the trade-off between selectivity and PK profile, structure-activity relationship (SAR) studies of terminal substituents on the pyrolidine ring were conducted. As a result, we developed potent PI3Kδ inhibitors with good oral availability. In particular, the representative compound 15j showed excellent selectivity for PI3Kδ over other PI3Ks with good oral exposure in mice. 10.1016/j.bmc.2018.03.042
    Simultaneous targeting of PI3Kδ and a PI3Kδ-dependent MEK1/2-Erk1/2 pathway for therapy in pediatric B-cell acute lymphoblastic leukemia. Wang Xiang,Zhang Xi,Li Ben-shang,Zhai Xiaowen,Yang Zhuo,Ding Li-xia,Wang Hongsheng,Liang Chris,Zhu Weiliang,Ding Jian,Meng Ling-hua Oncotarget B cell acute lymphoblastic leukemia (B-ALL) is the most common hematological malignancy diagnosed in children, and blockade of the abnormally activated PI3Kδ displayed promising outcomes in B cell acute or chronic leukemias, but the mechanisms are not well understood. Here we report a novel PI3Kδ selective inhibitor X-370, which displays distinct binding mode with p110δ and blocks constitutively active or stimulus-induced PI3Kδ signaling. X-370 significantly inhibited survival of human B cell leukemia cells in vitro, with associated induction of G1 phase arrest and apoptosis. X-370 abrogated both Akt and Erk1/2 signaling via blockade of PDK1 binding to and/or phosphorylation of MEK1/2. Forced expression of a constitutively active MEK1 attenuated the antiproliferative activity of X-370. X-370 preferentially inhibited the survival of primary pediatric B-ALL cells displaying PI3Kδ-dependent Erk1/2 phosphorylation, while combined inhibition of PI3Kδ and MEK1/2 displayed enhanced activity. We conclude that PI3Kδ inhibition led to abrogation of both Akt and Erk1/2 signaling via a novel PI3K-PDK1/MEK1/2-Erk1/2 signaling cascade, which contributed to its efficacy against B-ALL. These findings support the rationale for clinical testing of PI3Kδ inhibitors in pediatric B-ALL and provide insights needed to optimize the therapeutic strategy. 10.18632/oncotarget.2533
    Puquitinib, a novel orally available PI3Kδ inhibitor, exhibits potent antitumor efficacy against acute myeloid leukemia. Xie Chengying,He Ye,Zhen Mingyue,Wang Yulan,Xu Yongping,Lou Liguang Cancer science The PI3Kδ isoform (PIK3CD), also known as P110δ, is predominately expressed in leukocytes and has been implicated as a potential target in the treatment of hematological malignancies. In this report, we detailed the pharmacologic properties of puquitinib, a novel, orally available PI3Kδ inhibitor. Puquitinib, which binds to the ATP-binding pocket of PI3Kδ, was highly selective and potent for PI3Kδ relative to other PI3K isoforms and a panel of protein kinases, exhibiting low-nanomolar biochemical and cellular inhibitory potencies. Additional cellular profiling demonstrated that puquitinib inhibited proliferation, induced G -phase cell-cycle arrest and apoptosis in acute myeloid leukemia (AML) cell lines, through downregulation of PI3K signaling. In in vivo AML xenografts, puquitinib alone showed stronger efficacy than the well-known p110δ inhibitor, CAL-101, in association with a reduction in AKT and ERK phosphorylation in tumor tissues, without causing noticeable toxicity. Furthermore, the combination of puquitinib with cytotoxic drugs, especially daunorubicin, yielded significantly stronger antitumor efficacy compared with each agent alone. Thus, puquitinib is a promising agent with pharmacologic properties that are favorable for the treatment of AML. 10.1111/cas.13263
    Targeting PI3Kδ: emerging therapy for chronic lymphocytic leukemia and beyond. Wei Manman,Wang Xiang,Song Zilan,Jiao Mingkun,Ding Jian,Meng Ling-Hua,Zhang Ao Medicinal research reviews Chronic lymphocytic leukemia (CLL) remains the most incurable leukemia. Early chemotherapeutic treatments, including alkylating agents, purine nucleoside derivatives, and immunotherapeutic antibodies, only show limited benefits for patients but severe off-target related side effects. Recent advances in understanding of the critical molecular pathways of regulating proliferation and survival of B-CLL cells have spurred a new therapeutical strategy by selectively targeting phosphoinositide 3-kinase delta (PI3Kδ). Idelalisib, a first-in-class PI3Kδ-selective small molecule has received the FDA's fast-track approval in July of 2014 as a new treatment of CLL, indolent B-cell non-Hodgkin's lymphoma, and relapsed small lymphocytic lymphoma. Undoubtedly, the success of idelalisib has provided a solid support in the development of PI3Kδ-specific inhibitors and reformed the concept of treating CLL. However, the number of reported selective inhibitors of PI3Kδ is very limited and very few have advanced into clinical trials. The mechanism of their actions remains elusive. More profound understanding on the modes of action of new PI3Kδ inhibitors will further validate the PI3Kδ-targeting strategy, and help to identify biomarkers capable of stratifying patients who will most likely benefit from the therapy. 10.1002/med.21341
    Piperidinyl-embeded chalcones possessing anti PI3Kδ inhibitory properties exhibit anti-atopic properties in preclinical models. Dumontet Charles,Beck Guillaume,Gardebien Fabrice,Haudecoeur Romain,Mathé Doriane,Matera Eva-Laure,Tourette Anne,Mattei Eve,Esmenjaud Justine,Boyère Cédric,Nurisso Alessandra,Peuchmaur Marine,Pérès Basile,Bouchaud Grégory,Magnan Antoine,Monneret Guillaume,Boumendjel Ahcène European journal of medicinal chemistry Phosphatidylinositide 3-kinases (PI3Ks) are widely expressed enzymes involved in membrane signalization pathways. Attempts to administer inhibitors with broad activity against different isoforms have failed due to toxicity. Conversely the PI3Kδ isoform is much more selectively expressed, enabling therapeutic targeting of this isoform. Of particular interest PI3Kδ is expressed in human basophils and its inhibition has been shown to reduce anti-IgE induced basophil degranulation, suggesting that PI3Kδ inhibitors could be useful as anti-allergy drugs. Herein, we report for the first time the activity of compounds derived from chalcone scaffolds as inhibitors of normal human basophil degranulation and identified the most active compound with anti-PI3Kδ properties that was investigated in preclinical models. Compound 18, namely 1-[2-hydroxy-4,6-dimethoxy-3-(N-methylpiperidin-4-yl)phenyl]-3-(2,4,6-trimethoxyphenyl)-prop-2-en-1-one, was found to inhibit normal human basophil degranulation in a dose-dependent manner. In a murine model of ovalbumin-induced asthma, compound 18 was shown to reduce expiratory pressure while its impact on the inflammatory infiltrate in alveolar lavage and total lung was dependent on the route of administration. In a DNFB-induced model of atopic dermatitis compound 18 administered systemically proved to be as potent as topical betamethasone. These results support the anti-atopic and allergic properties of the title compound and warrant further clinical development. 10.1016/j.ejmech.2018.09.033
    Identification of new dual spleen tyrosine kinase (Syk) and phosphoionositide-3-kinase δ (PI3Kδ) inhibitors using ligand and structure-based integrated ideal pharmacophore models. Kaur M,Silakari O SAR and QSAR in environmental research Owing to the complex pathophysiology of autoimmune disorders, it is very challenging to develop successful treatment strategies. Single-target agents are not desired therapeutics for such multi-factorial disorders. Considering the current need for the treatment of complex autoimmune disorders, dual inhibitors of Syk and PI3Kδ have been designed using ligand and structure-based molecular modelling strategies. In the present work, structure and ligand-based pharmacophore modelling was implemented for a varied set of Syk and PI3Kδ inhibitors. Ligand-based pharmacophore models (LBPMs) were developed for two kinases: ADPR.14 (r(2)train = 0.809) for Syk, comprising one hydrogen bond acceptor, one hydrogen bond donor, one positive ionisable and one ring aromatic feature, and for PI3Kδ: AAARR.45 (r(2)train = 0.942) consisting of three hydrogen bond acceptor and two ring aromatic features. The generated e-pharmacophore models revealed an additional ring aromatic and hydrophobic feature important for Syk and PI3Kδ inhibition, respectively. Subsequently, LBPMs were modified resulting in APDRR.14 hypothesis for Syk inhibitors and AAAHRR.45 hypothesis for PI3Kδ inhibitors employed for virtual screening. Thus, the combination of ligand and structure-based pharmacophore modelling helped in developing ideal pharmacophore models that may be an efficient tool for the designing of novel dual inhibitors of Syk and PI3Kδ. 10.1080/1062936X.2016.1209555
    An investigation of the anti-inflammatory effects and a potential biomarker of PI3Kδ inhibition in COPD T cells. Khan Abid,Southworth Thomas,Worsley Sally,Sriskantharajah Srividya,Amour Augustin,Hessel Edith M,Singh Dave Clinical and experimental pharmacology & physiology Lymphocyte numbers are increased in the lungs of chronic obstructive pulmonary disease (COPD) patients. Phosphatidylinositol-3-kinase delta (PI3Kδ) is involved in lymphocyte activation. We investigated the effect of PI3Kδ inhibition on cytokine release from COPD lymphocytes. We also evaluated phosphorylated ribosomal S6 protein (rS6) as a potential biomarker of PI3Kδ activation. Peripheral blood mononuclear cells (PBMCs) and bronchoalveolar lavage (BAL) cells isolated from healthy never smokers (HNS), smokers (S) and COPD patients were stimulated to induce a T cell receptor response. The effects of a PI3Kδ specific inhibitor (GSK045) on cytokine release and rS6 phosphorylation were measured by Luminex and flow cytometry respectively. The effects of GSK045 on cytokine production from PHA stimulated chopped lung samples were investigated. GSK045 reduced cytokine release from PBMCs, BAL cells and chopped lung. Inhibition was greatest in the chopped lung model, with approximately 80% inhibition of interferon (IFN) γ, interleukin (IL)-2, IL-17 and IL-10. PI3Kδ inhibition suppressed rS6 phosphorylation in unstimulated airway T-lymphocytes by up to 60%. Inhibition of PI3Kδ suppressed T cell cytokine production in COPD patients. rS6 phosphorylation shows potential as a biomarker to assess PI3Kδ activity. 10.1111/1440-1681.12784
    Anti-inflammatory potential of PI3Kδ and JAK inhibitors in asthma patients. Southworth Thomas,Plumb Jonathan,Gupta Vandana,Pearson James,Ramis Isabel,Lehner Martin D,Miralpeix Montserrat,Singh Dave Respiratory research BACKGROUND:Phosphatidylinositol 3-kinase delta (PI3Kδ) and Janus-activated kinases (JAK) are both novel anti-inflammatory targets in asthma that affect lymphocyte activation. We have investigated the anti-inflammatory effects of PI3Kδ and JAK inhibition on cytokine release from asthma bronchoalveolar lavage (BAL) cells and T-cell activation, and measured lung PI3Kδ and JAK signalling pathway expression. METHOD:Cells isolated from asthma patients and healthy subjects were treated with PI3Kδ or JAK inhibitors, and/or dexamethasone, before T-cell receptor stimulation. Levels of IFNγ, IL-13 and IL-17 were measured by ELISA and flow cytometry was used to assess T-cell activation. PI3Kδ, PI3Kγ, phosphorylated protein kinase B (pAKT) and Signal Transducer and Activator of Transcription (STAT) protein expression were assessed by immunohistochemistry in bronchial biopsy tissue from asthma patients and healthy subjects. PI3Kδ expression in BAL CD3 cells was measured by flow cytometry. RESULTS:JAK and PI3Kδ inhibitors reduced cytokine levels from both asthma and healthy BAL cells. Combining dexamethasone with either a JAK or PI3Kδ inhibitor showed an additive anti-inflammatory effect. JAK and PI3Kδ inhibitors were shown to have direct effects on T-cell activation. Immunohistochemistry showed increased numbers of PI3Kδ expressing cells in asthma bronchial tissue compared to controls. Asthma CD3 cells in BAL expressed higher levels of PI3Kδ protein compared to healthy cells. CONCLUSIONS:Targeting PI3Kδ or JAK may prove effective in reducing T-cell activation and the resulting cytokine production in asthma. 10.1186/s12931-016-0436-2
    PI3Kδ and PI3Kγ isoforms have distinct functions in regulating pro-tumoural signalling in the multiple myeloma microenvironment. Piddock R E,Loughran N,Marlein C R,Robinson S D,Edwards D R,Yu S,Pillinger G E,Zhou Z,Zaitseva L,Auger M J,Rushworth S A,Bowles K M Blood cancer journal Phosphoinositide-3-kinase and protein kinase B (PI3K-AKT) is upregulated in multiple myeloma (MM). Using a combination of short hairpin RNA (shRNA) lentivirus-mediated knockdown and pharmacologic isoform-specific inhibition we investigated the role of the PI3K p110γ (PI3Kγ) subunit in regulating MM proliferation and bone marrow microenvironment-induced MM interactions. We compared this with inhibition of the PI3K p110δ (PI3kδ) subunit and with combined PI3kδ/γ dual inhibition. We found that MM cell adhesion and migration were PI3Kγ-specific functions, with PI3kδ inhibition having no effect in MM adhesion or migration assays. At concentration of the dual PI3Kδ/γ inhibitor duvelisib, which can be achieved in vivo we saw a decrease in AKT phosphorylation at s473 after tumour activation by bone marrow stromal cells (BMSC) and interleukin-6. Moreover, after drug treatment of BMSC/tumour co-culture activation assays only dual PI3kδ/γ inhibition was able to induce MM apoptosis. shRNA lentiviral-mediated targeting of either PI3Kδ or PI3Kγ alone, or both in combination, increased survival of NSG mice xeno-transplanted with MM cells. Moreover, treatment with duvelisib reduced MM tumour burden in vivo. We report that PI3Kδ and PI3Kγ isoforms have distinct functions in MM and that combined PI3kδ/γ isoform inhibition has anti-MM activity. Here we provide a scientific rationale for trials of dual PI3kδ/γ inhibition in patients with MM. 10.1038/bcj.2017.16
    Regulation of T cell alloimmunity by PI3Kγ and PI3Kδ. Uehara Mayuko,McGrath Martina M,Ohori Shunsuke,Solhjou Zhabiz,Banouni Naima,Routray Sujit,Evans Catherine,DiNitto Jonathan P,Elkhal Abdallah,Turka Laurence A,Strom Terry B,Tullius Stefan G,Winkler David G,Azzi Jamil,Abdi Reza Nature communications Phosphatidylinositol-3-kinases (PI3K) γ and δ are preferentially enriched in leukocytes, and defects in these signaling pathways have been shown to impair T cell activation. The effects of PI3Kγ and PI3Kδ on alloimmunity remain underexplored. Here, we show that both PI3Kγ and PI3Kδ mice receiving heart allografts have suppression of alloreactive T effector cells and delayed acute rejection. However, PI3Kδ mutation also dampens regulatory T cells (Treg). After treatment with low dose CTLA4-Ig, PI3Kγ , but not PI3Κδ , recipients exhibit indefinite prolongation of heart allograft survival. PI3Kδ Tregs have increased apoptosis and impaired survival. Selective inhibition of PI3Kγ and PI3Kδ (using PI3Kδ and dual PI3Kγδ chemical inhibitors) shows that PI3Kγ inhibition compensates for the negative effect of PI3Kδ inhibition on long-term allograft survival. These data serve as a basis for future PI3K-based immune therapies for transplantation.Phosphatidylinositol-3-kinases (PI3K) γ and δ are key regulators of T cell signaling. Here the author show, using mouse heart allograft transplantation models, that PI3Kγ or PI3Kδ deficiency prolongs graft survival, but selective inhibition of PI3Kγ or PI3Kδ reveals alternative transplant survival outcomes post CTLA4-Ig treatment. 10.1038/s41467-017-00982-x
    Effective "activated PI3Kδ syndrome"-targeted therapy with the PI3Kδ inhibitor leniolisib. Rao V Koneti,Webster Sharon,Dalm Virgil A S H,Šedivá Anna,van Hagen P Martin,Holland Steven,Rosenzweig Sergio D,Christ Andreas D,Sloth Birgitte,Cabanski Maciej,Joshi Aniket D,de Buck Stefan,Doucet Julie,Guerini Danilo,Kalis Christoph,Pylvaenaeinen Ilona,Soldermann Nicolas,Kashyap Anuj,Uzel Gulbu,Lenardo Michael J,Patel Dhavalkumar D,Lucas Carrie L,Burkhart Christoph Blood Pathogenic gain-of-function variants in the genes encoding phosphoinositide 3-kinase δ (PI3Kδ) lead to accumulation of transitional B cells and senescent T cells, lymphadenopathy, and immune deficiency (activated PI3Kδ syndrome [APDS]). Knowing the genetic etiology of APDS afforded us the opportunity to explore PI3Kδ inhibition as a precision-medicine therapy. Here, we report in vitro and in vivo effects of inhibiting PI3Kδ in APDS. Treatment with leniolisib (CDZ173), a selective PI3Kδ inhibitor, caused dose-dependent suppression of PI3Kδ pathway hyperactivation (measured as phosphorylation of AKT/S6) in cell lines ectopically expressing APDS-causative p110δ variants and in T-cell blasts derived from patients. A clinical trial with 6 APDS patients was conducted as a 12-week, open-label, multisite, within-subject, dose-escalation study of oral leniolisib to assess safety, pharmacokinetics, and effects on lymphoproliferation and immune dysregulation. Oral leniolisib led to a dose-dependent reduction in PI3K/AKT pathway activity assessed ex vivo and improved immune dysregulation. We observed normalization of circulating transitional and naive B cells, reduction in PD-1CD4 and senescent CD57CD4 T cells, and decreases in elevated serum immunoglobulin M and inflammatory markers including interferon γ, tumor necrosis factor, CXCL13, and CXCL10 with leniolisib therapy. After 12 weeks of treatment, all patients showed amelioration of lymphoproliferation with lymph node sizes and spleen volumes reduced by 39% (mean; range, 26%-57%) and 40% (mean; range, 13%-65%), respectively. Thus, leniolisib was well tolerated and improved laboratory and clinical parameters in APDS, supporting the specific inhibition of PI3Kδ as a promising new targeted therapy in APDS and other diseases characterized by overactivation of the PI3Kδ pathway. This trial was registered at www.clinicaltrials.gov as #NCT02435173. 10.1182/blood-2017-08-801191
    Combined inhibition of PI3Kδ and FLT3 signaling exerts synergistic antitumor activity and overcomes acquired drug resistance in FLT3-activated acute myeloid leukemia. He Ye,Sun Liping,Xu Yongping,Fu Li,Li Yun,Bao Xubin,Fu Haoyu,Xie Chengying,Lou Liguang Cancer letters PI3Kδ and FLT3 are frequently activated in acute myeloid leukemia (AML) and have been implicated as potential therapeutic targets. In this report, we demonstrate that combined inhibition of PI3Kδ and FLT3 exerts synergistic antitumor activity in FLT3-activated AML. Synergistic antiproliferative effects were observed in FLT3-activated MV-4-11 and EOL-1 AML cell lines, but not in FLT3-independent RS4;11 and HEL cells, as demonstrated by both pharmacological inhibition and silencing of PI3Kδ/FLT3. Combined treatment with PI3Kδ and FLT3 inhibitors more effectively inhibited AKT and ERK phosphorylation, and induced apoptosis more efficiently than either agent alone. This synergistic effect was confirmed in hematopoietic 32D cells transfected with an FLT3-ITD mutant, but not FLT3 wild type. In in vivo FLT3-activated AML xenografts, a PI3Kδ inhibitor CAL101 combined with FLT3 inhibitor led to significantly enhanced antitumor activity compared with either agent alone, in association with simultaneous inhibition of AKT and ERK. Importantly, CAL101 combined with FLT3 inhibitors overcame acquired drug resistance in FLT3-ITD AML cells. Thus, combined inhibition of PI3Kδ and FLT3 may be a promising strategy in FLT3-activated AML, particularly for patients with FLT3-inhibitor-resistant mutations. 10.1016/j.canlet.2018.01.071
    Targeting PI3Kδ function for amelioration of murine chronic graft-versus-host disease. Paz Katelyn,Flynn Ryan,Du Jing,Tannheimer Stacey,Johnson Amy J,Dong Shuai,Stark Anne-Katrien,Okkenhaug Klaus,Panoskaltsis-Mortari Angela,Sage Peter T,Sharpe Arlene H,Luznik Leo,Ritz Jerome,Soiffer Robert J,Cutler Corey S,Koreth John,Antin Joseph H,Miklos David B,MacDonald Kelli P,Hill Geoffrey R,Maillard Ivan,Serody Jonathan S,Murphy William J,Munn David H,Feser Colby,Zaiken Michael,Vanhaesebroeck Bart,Turka Laurence A,Byrd John C,Blazar Bruce R American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons Chronic graft-versus-host disease (cGVHD) is a leading cause of morbidity and mortality following allotransplant. Activated donor effector T cells can differentiate into pathogenic T helper (Th)-17 cells and germinal center (GC)-promoting T follicular helper (Tfh) cells, resulting in cGVHD. Phosphoinositide-3-kinase-δ (PI3Kδ), a lipid kinase, is critical for activated T cell survival, proliferation, differentiation, and metabolism. We demonstrate PI3Kδ activity in donor T cells that become Tfh cells is required for cGVHD in a nonsclerodermatous multiorgan system disease model that includes bronchiolitis obliterans (BO), dependent upon GC B cells, Tfhs, and counterbalanced by T follicular regulatory cells, each requiring PI3Kδ signaling for function and survival. Although B cells rely on PI3Kδ pathway signaling and GC formation is disrupted resulting in a substantial decrease in Ig production, PI3Kδ kinase-dead mutant donor bone marrow-derived GC B cells still supported BO cGVHD generation. A PI3Kδ-specific inhibitor, compound GS-649443, that has superior potency to idelalisib while maintaining selectivity, reduced cGVHD in mice with active disease. In a Th1-dependent and Th17-associated scleroderma model, GS-649443 effectively treated mice with active cGVHD. These data provide a foundation for clinical trials of US Food and Drug Administration (FDA)-approved PI3Kδ inhibitors for cGVHD therapy in patients. 10.1111/ajt.15305
    Introduction of pyrrolidineoxy or piperidineamino group at the 4-position of quinazoline leading to novel quinazoline-based phosphoinositide 3-kinase delta (PI3Kδ) inhibitors. Xin Minhang,Duan Weiming,Feng Yifan,Hei Yuan-Yuan,Zhang Hao,Shen Ying,Zhao Hong-Yi,Mao Shuai,Zhang San-Qi Journal of enzyme inhibition and medicinal chemistry Phosphoinositide 3-kinase Delta (PI3Kδ) plays a key role in B-cell signal transduction and inhibition of PI3Kδ was confirmed to have clinical benefit in certain types of activation of B-cell malignancies. Herein, we reported a novel series of 4-pyrrolidineoxy or 4-piperidineamino substituted quinazolines, showing potent PI3Kδ inhibitory activities. Among these compounds, 12d, 14b and 14c demonstrated higher potency against PI3Kδ with the half maximal inhibitory concentration (IC) values of 4.5, 3.0, and 3.9 nM, respectively, which were comparable to idelalisib (IC = 2.7 nM). The further PI3K isoforms selectivity evaluation showed that compounds 12d, 14b and 14c have excellent PI3Kδ selectivity over PI3Kα, PI3Kβ, and PI3Kγ. Moreover, compounds 12d, 14b and 14c also displayed different anti-proliferative profiles against a panel of four human B cell lines including Ramos, Raji, RPMI-8226, and SU-DHL-6. The molecular docking simulation indicated several key hydrogen bonding interactions were formed. This study suggests the introduction of pyrrolidineoxy or piperidineamino groups into the 4-position of quinazoline leads to new potent and selective PI3Kδ inhibitors. 10.1080/14756366.2018.1444608
    PI3Kδ Is a Therapeutic Target in Hepatocellular Carcinoma. Ko Eunkyong,Seo Hyun-Wook,Jung Eun Sun,Ju Soomi,Kim Baek-Hui,Cho Hyeki,Kim Yoon Jun,Park Young Min,Kim Jong-Seo,Jung Guhung Hepatology (Baltimore, Md.) Class I phosphoinositide 3-kinase (PI3K) signaling is a major pathway in human cancer development and progression. Among the four PI3K isoforms, PI3Kα and PI3Kβ are ubiquitously expressed, whereas PI3Kγ and PI3Kδ are found primarily in leukocytes. Until now, PI3K targeting in solid tumors has focused on inhibiting PI3Kα-mediated and PI3Kβ-mediated cancer cell-intrinsic PI3K activity. The role of PI3Kδ in solid tumors is unknown. Here, we evaluated the effects of PI3Kδ using established hepatocellular carcinoma (HCC) cells, malignant hepatocytes derived from patients with advanced HCC, murine models, and HCC tissues using RNA sequencing, quantitative PCR, immunoblotting, immunofluorescence, microarray, liquid chromatography-tandem mass spectrometry, and kinase assay. We established a chemical carcinogenesis model of liver malignancy that reflects the malignant phenotype and the in vivo environment of advanced HCC. In this in vivo advanced HCC-mimic system using HCC cells treated with hydrogen peroxide (H O ), we showed that H O selectively increases PI3Kδ activity while decreasing that of other class I PI3Ks. Blocking PI3Kδ activity with a PI3Kδ inhibitor or small interfering RNA-mediated PI3Kδ gene silencing inhibited HCC-cell proliferation and dampened key features of malignant HCC, including the up-regulation of telomerase reverse transcriptase (TERT). Mechanistically, H O induced oxidative modification of the serpin peptidase inhibitor, serpin peptidase inhibitor (SERPINA3), blocking its ubiquitin-dependent degradation and enhancing its activity as a transcriptional activator of PI3Kδ and TERT. High PI3Kδ levels in HCC were found to correlate with poor survival rates, with human advanced HCC showing positive correlations between the protein levels of oxidized SERPINA3, PI3Kδ, and TERT. Thus, PI3Kδ plays significant roles in malignant liver tumors. Conclusion: Our data identify PI3Kδ inhibition, recently approved for the treatment of human B-cell malignancies, as a potential treatment for HCC. 10.1002/hep.30307
    Discovery of novel quinazolinone derivatives as high potent and selective PI3Kδ and PI3Kδ/γ inhibitors. Ma Chen-Chen,Zhang Cheng-Mei,Tang Long-Qian,Liu Zhao-Peng European journal of medicinal chemistry PI3Kδ and PI3Kγ regulate immune cell signaling. Selective PI3Kδ or PI3Kγ inhibitors and dual PI3Kδ/γ inhibitors have the potential for the treatment of immune cell-mediated diseases and hematological malignancies. Based on the quinazolinone pharmacophore, we used a pyrazolo[3,4-d]pyrimidin-4-amine portion as the hinge region binding moiety, an aromatic or a heteroaromatic substituent at the 3-position of the pyrazolo[3,4-d]pyrimidine core as the affinity element, and designed novel 2-tolyl and 2,6-dimethylphenyl quinazolinone derivatives as potential PI3Kδ inhibitors. Most of these compounds displayed high inhibitory rates (89-97%) against PI3Kδ at the concentration of 1 μM, with the IC values of 8.4 nM-106 nM. Among the 3-(2,6-dimethylphenyl)quinazolinone series, the introduction of an indol-5-yl substituent at the pyrazolo[3,4-d]pyrimidine 3-position led to a potent and selective PI3Kδ (IC = 8.6 nM) inhibitor 10d, that was more than 3630-fold, 390-fold and 40-fold selective for PI3Kδ over PI3Kα, β and γ, while the substitution with a 3,4-dimethoxyphenyl resulted in a potent and selective dual PI3Kδ/γ inhibitor 10e with IC values of 8.4 nM and 62 nM against PI3Kδ and PI3Kγ, respectively. Compound 10e was also more than 1400-fold, 820-fold selective for PI3Kδ over PI3Kα and PI3Kβ. In agreement with their remarkable PI3Kδ inhibitory activity, compounds 10d and 10e showed high antiproliferative activity against human B-cell SU-DHL-6 cells. Moreover, the dual PI3Kδ/γ inhibitor 10e had reasonable pharmacokinetic profiles with a good plasma exposure, low clearance, low volume distribution, and an acceptable oral bioavailability of 34.9%. 10.1016/j.ejmech.2018.03.068
    PI3Kδ inhibition modulates regulatory and effector T-cell differentiation and function in chronic lymphocytic leukemia. Hanna Bola S,Roessner Philipp M,Scheffold Annika,Jebaraj Billy M C,Demerdash Yasmin,Öztürk Selcen,Lichter Peter,Stilgenbauer Stephan,Seiffert Martina Leukemia Targeting B-cell receptor signaling using the PI3Kδ inhibitor idelalisib is a highly effective treatment option for relapsed/refractory chronic lymphocytic leukemia (CLL) patients. In addition to its direct impact on tumor cells, PI3Kδ inhibition can modulate the activity of regulatory T-cells (Tregs) resulting in enhanced anti-tumoral immune functions which may contribute to the success of PI3Kδ inhibitors in cancer therapy. The role of Tregs in CLL and their modulation by PI3Kδ inhibitors was so far poorly understood. Using the Eµ-TCL1 adoptive transfer model of CLL, we show that disease development induces the accumulation of activated and highly immunosuppressive Tregs. Depletion of CD25 Tregs using anti-CD25 antibodies resulted in enhanced CD8 T-cell activation, effector differentiation, and functional capacity. We further show that pharmacological inhibition of PI3Kδ effectively controlled disease and significantly decreased both CD25 and CD25 Treg numbers, proliferation and activation status in CLL-bearing mice. Nonetheless, this PI3Kδ-mediated decrease in Tregs did not translate into better CD8 T-cell function, as PI3Kδ inhibition concomitantly abrogated T-cell receptor signaling in CD8 T-cells leading to decreased activation, effector cell differentiation and proliferation. Collectively, these data highlight the strong immunomodulatory effects of PI3Kδ inhibitors in CLL and are of relevance for a rational design of idelalisib-based combination therapies in CLL. 10.1038/s41375-018-0318-3
    PI3Kδ inhibitors for the treatment of cancer: a patent review (2015-present). Feng Yifan,Cu Xiaochuan,Xin Minhang Expert opinion on therapeutic patents : PI3Kδ is an important subtype of PI3K kinases, which is mainly expressed in leukocytes and plays an important role in the proliferation, differentiation, maturation and self-reaction of B cells. It is an effective target in the treatment of hematological malignancies and autoimmune diseases such as rheumatoid arthritis. Therefore, many pharmaceutical companies and research institutions have focused on the PI3Kδ subtype in an attempt to develop potent and selective PI3Kδ inhibitors.: This review aims to provide an overview of the patented selective PI3Kδ inhibitors in treating cancer from 2015 to present.: Due to the importance of PI3Kδ, the development of selective PI3Kδ inhibitors for the treatment of hematoma and autoimmune diseases is expected. On 23 July 2014, the world's first selective PI3Kδ inhibitor, idelalisib, was approved by the FDA for the treatment of CLL, FL and SLL. Moreover, there are still many small molecule selective PI3Kδ inhibitors at different stages of development. The future research effort for development of PI3Kδ inhibitors is to manage the toxicity and lower the side-effects. 10.1080/13543776.2019.1687685
    Synthesis and biological evaluation of 4-(piperid-3-yl)amino substituted 6-pyridylquinazolines as potent PI3Kδ inhibitors. Feng Yifan,Duan Weiming,Fan Shu,Zhang Hao,Zhang San-Qi,Xin Minhang Bioorganic & medicinal chemistry PI3Kδ is an intriguing target for developing anti-cancer agent. In this study, a new series of 4-(piperid-3-yl)amino substituted 6-pyridylquinazoline derivatives were synthesized. After biological evaluation, compounds A5 and A8 were identified as potent PI3Kδ inhibitors, with IC values of 1.3 and 0.7 nM, respectively, which are equivalent to or better than idelalisib (IC = 1.2 nM). Further PI3K isoforms selectivity evaluation showed that compound A5 afforded excellent PI3Kδ selectivity over PI3Kα, PI3Kβ and PI3Kγ. A8 exhibited superior PI3Kδ/γ selectivity over PI3Kα and PI3Kβ. Moreover, compounds A5 and A8 selectively exhibited anti-proliferation against SU-DHL-6 in vitro with IC values of 0.16 and 0.12 μM. Western blot analysis indicated that A8 could attenuate the AKT phosphorylation. Molecular docking study suggested that A8 formed three key H-bonds action with PI3Kδ, which may account for its potent inhibition of PI3Kδ. These findings indicate that 4-(piperid-3-yl)amino substituted 6-pyridylquinazoline derivatives were potent PI3Kδ inhibitors with distinctive PI3K-isoforms and anti-proliferation profiles. 10.1016/j.bmc.2019.07.051
    Synergistic suppression of the PI3K inhibitor CAL-101 with bortezomib on mantle cell lymphoma growth. Qu Fu-Lian,Xia Bing,Li Su-Xia,Tian Chen,Yang Hong-Liang,Li Qian,Wang Ya-Fei,Yu Yong,Zhang Yi-Zhuo Cancer biology & medicine OBJECTIVE:To investigate the effects of CAL-101, particularly when combined with bortezomib (BTZ) on mantle cell lymphoma (MCL) cells, and to explore its relative mechanisms. METHODS:MTT assay was applied to detect the inhibitory effects of different concentrations of CAL-101. MCL cells were divided into four groups: control group, CAL-101 group, BTZ group, and CAL-101/BTZ group. The expression of PI3K-p110σ, AKT, ERK, p-AKT and p-ERK were detected by Western blot. The apoptosis rates of CAL-101 group, BTZ group, and combination group were detected by flow cytometry. The location changes of nuclear factor kappa-B (NF-κB) of 4 groups was investigated by NF-κB Kit exploring. Western blot was applied to detect the levels of caspase-3 and the phosphorylation of AKT in different groups. RESULTS:CAL-101 dose- and time-dependently induced reduction in MCL cell viability. CAL-101 combined with BTZ enhanced the reduction in cell viability and apoptosis. Western blot analysis showed that CAL-101 significantly blocked the PI3K/AKT and ERK signaling pathway in MCL cells. The combination therapy contributed to the inactivation of NF-κB and AKT in MCL cell lines. However, cleaved caspase-3 was up-regulated after combined treatment. CONCLUSION:Our study showed that PI3K/p110σ is a novel therapeutic target in MCL, and the underlying mechanism could be the blocking of the PI3K/AKT and ERK signaling pathways. These findings provided a basis for clinical evaluation of CAL-101 and a rationale for its application in combination therapy, particularly with BTZ. 10.7497/j.issn.2095-3941.2015.0013
    [Effects of the phosphoinostitide-3'-kinase delta inhibitor, CAL-101, in combination with Bortezomib on mantle lymophma cells and exploration of its related mechanism]. Qu Fulian,Xia Bing,Li Xiaowu,Guo Shanqi,Zhang Le,Tian Chen,Yu Yong,Zhang Yizhuo Zhonghua zhong liu za zhi [Chinese journal of oncology] OBJECTIVE:To investigate the effect of CAL-101, a selective inhibitor of PI3Kδ, in combination with bortezomib on the proliferation and apoptosis in human mantle cell lymphoma cell lines Z138, HBL-2 and Jeko-1 in vitro, to explore its mechanisms and provide the foundation for effective treatment strategies against mantle cell lymphoma. METHODS:MTT assay was applied to detect the inhibitory effects of CAL-101 and bortezomib either alone or combined on Z138, HBL-2 and Jeko-1 cells. Calcusyn software was used to analyze the synergistic cytotoxicity. Western blot was used to detect the expression of PI3K-p110σ and p-Akt, Akt, p-ERK and ERK proteins after the cells were exposed to different concentrations of CAL-101. Flow cytometry was employed to assess the apoptosis rate. NF-κB kit was used to determine the changes of location of NF-κB P65, and Western blot was applied to detect the level of caswpase-3 and the phosphorylation of Akt in different groups. RESULTS:CAL-101 and BTZ inhibited the proliferation of Z138, HBL-2 and Jeko-1 cells in a dose- and time-dependent manner. CAL-101/BTZ combination induced significantly synergistic cytotoxicity in the MCL cells. The results of Western blot assay showed that CAL-101 significantly blocked the phosphorylation of Akt and ERK in the MCL cell lines. In addition, CAL-101 combined with BTZ induced pronounced apoptosis (P < 0.01). For example, after the Z138 cells exposed to the drugs for 48 h, the apoptosis rates of the control, CAL-101, BTZ and CAL-101 + BTZ groups were: (2.6 ± 1.8)%, (40.0 ± 3.0)%, (34.0 ± 1.0)%, and (67.4 ± 1.0)%, respectively; and when drug treatment was given to HBL-2 cells over 96 h, the apoptosis rates of these four cell groups were (7.4 ± 0.6)%, (30.7 ± 5.7)%, (12.0 ± 1.0)%, and (85.0 ± 4.0)%, respectively. The combination therapy contributed to the enhanced inactivity of nuclear factor-κB (NF-κB) and Akt inactivation in the MCL cell lines (P < 0.05), however, the casepase-3 activity was up-regulated. CONCLUSIONS:The combination of CAL-101 and bortezomib is muchmore effective in inhibiting proliferation and promoting apoptosis of mantle cell lymphoma cell lines (Z138, HBL-2 and Jeko-1), which may be mediated through inhibiting PI3K/Akt signaling pathway and the transcription of NF-κB.