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    Molecularly targeted drug combinations demonstrate selective effectiveness for myeloid- and lymphoid-derived hematologic malignancies. Kurtz Stephen E,Eide Christopher A,Kaempf Andy,Khanna Vishesh,Savage Samantha L,Rofelty Angela,English Isabel,Ho Hibery,Pandya Ravi,Bolosky William J,Poon Hoifung,Deininger Michael W,Collins Robert,Swords Ronan T,Watts Justin,Pollyea Daniel A,Medeiros Bruno C,Traer Elie,Tognon Cristina E,Mori Motomi,Druker Brian J,Tyner Jeffrey W Proceedings of the National Academy of Sciences of the United States of America Translating the genetic and epigenetic heterogeneity underlying human cancers into therapeutic strategies is an ongoing challenge. Large-scale sequencing efforts have uncovered a spectrum of mutations in many hematologic malignancies, including acute myeloid leukemia (AML), suggesting that combinations of agents will be required to treat these diseases effectively. Combinatorial approaches will also be critical for combating the emergence of genetically heterogeneous subclones, rescue signals in the microenvironment, and tumor-intrinsic feedback pathways that all contribute to disease relapse. To identify novel and effective drug combinations, we performed ex vivo sensitivity profiling of 122 primary patient samples from a variety of hematologic malignancies against a panel of 48 drug combinations. The combinations were designed as drug pairs that target nonoverlapping biological pathways and comprise drugs from different classes, preferably with Food and Drug Administration approval. A combination ratio (CR) was derived for each drug pair, and CRs were evaluated with respect to diagnostic categories as well as against genetic, cytogenetic, and cellular phenotypes of specimens from the two largest disease categories: AML and chronic lymphocytic leukemia (CLL). Nearly all tested combinations involving a BCL2 inhibitor showed additional benefit in patients with myeloid malignancies, whereas select combinations involving PI3K, CSF1R, or bromodomain inhibitors showed preferential benefit in lymphoid malignancies. Expanded analyses of patients with AML and CLL revealed specific patterns of ex vivo drug combination efficacy that were associated with select genetic, cytogenetic, and phenotypic disease subsets, warranting further evaluation. These findings highlight the heuristic value of an integrated functional genomic approach to the identification of novel treatment strategies for hematologic malignancies. 10.1073/pnas.1703094114
    Atypical chronic myeloid leukemia is clinically distinct from unclassifiable myelodysplastic/myeloproliferative neoplasms. Wang Sa A,Hasserjian Robert P,Fox Patricia S,Rogers Heesun J,Geyer Julia T,Chabot-Richards Devon,Weinzierl Elizabeth,Hatem Joseph,Jaso Jesse,Kanagal-Shamanna Rashmi,Stingo Francesco C,Patel Keyur P,Mehrotra Meenakshi,Bueso-Ramos Carlos,Young Ken H,Dinardo Courtney D,Verstovsek Srdan,Tiu Ramon V,Bagg Adam,Hsi Eric D,Arber Daniel A,Foucar Kathryn,Luthra Raja,Orazi Attilio Blood Atypical chronic myeloid leukemia (aCML) is a rare subtype of myelodysplastic/myeloproliferative neoplasm (MDS/MPN) largely defined morphologically. It is, unclear, however, whether aCML-associated features are distinctive enough to allow its separation from unclassifiable MDS/MPN (MDS/MPN-U). To study these 2 rare entities, 134 patient archives were collected from 7 large medical centers, of which 65 (49%) cases were further classified as aCML and the remaining 69 (51%) as MDS/MPN-U. Distinctively, aCML was associated with many adverse features and an inferior overall survival (12.4 vs 21.8 months, P = .004) and AML-free survival (11.2 vs 18.9 months, P = .003). The aCML defining features of leukocytosis and circulating myeloid precursors, but not dysgranulopoiesis, were independent negative predictors. Other factors, such as lactate dehydrogenase, circulating myeloblasts, platelets, and cytogenetics could further stratify MDS/MPN-U but not aCML patient risks. aCML appeared to have more mutated RAS (7/20 [35%] vs 4/29 [14%]) and less JAK2p.V617F (3/42 [7%] vs 10/52 [19%]), but was not statistically significant. Somatic CSF3R T618I (0/54) and CALR (0/30) mutations were not detected either in aCML or MDS/MPN-U. In conclusion, within MDS/MPN, the World Health Organization 2008 criteria for aCML identify a subgroup of patients with features clearly distinct from MDS/MPN-U. The MDS/MPN-U category is heterogeneous, and patient risk can be further stratified by a number of clinicopathological parameters. 10.1182/blood-2014-02-553800
    Sequential gain of mutations in severe congenital neutropenia progressing to acute myeloid leukemia. Beekman Renée,Valkhof Marijke G,Sanders Mathijs A,van Strien Paulette M H,Haanstra Jurgen R,Broeders Lianne,Geertsma-Kleinekoort Wendy M,Veerman Anjo J P,Valk Peter J M,Verhaak Roel G,Löwenberg Bob,Touw Ivo P Blood Severe congenital neutropenia (SCN) is a BM failure syndrome with a high risk of progression to acute myeloid leukemia (AML). The underlying genetic changes involved in SCN evolution to AML are largely unknown. We obtained serial hematopoietic samples from an SCN patient who developed AML 17 years after the initiation of G-CSF treatment. Next- generation sequencing was performed to identify mutations during disease progression. In the AML phase, we found 12 acquired nonsynonymous mutations. Three of these, in CSF3R, LLGL2, and ZC3H18, co-occurred in a subpopulation of progenitor cells already in the early SCN phase. This population expanded over time, whereas clones harboring only CSF3R mutations disappeared from the BM. The other 9 mutations were only apparent in the AML cells and affected known AML-associated genes (RUNX1 and ASXL1) and chromatin remodelers (SUZ12 and EP300). In addition, a novel CSF3R mutation that conferred autonomous proliferation to myeloid progenitors was found. We conclude that progression from SCN to AML is a multistep process, with distinct mutations arising early during the SCN phase and others later in AML development. The sequential gain of 2 CSF3R mutations implicates abnormal G-CSF signaling as a driver of leukemic transformation in this case of SCN. 10.1182/blood-2012-01-406116
    Granulocyte colony-stimulating factor (G-CSF) treatment of childhood acute myeloid leukemias that overexpress the differentiation-defective G-CSF receptor isoform IV is associated with a higher incidence of relapse. Ehlers Stephanie,Herbst Christin,Zimmermann Martin,Scharn Nicole,Germeshausen Manuela,von Neuhoff Nils,Zwaan Christian Michel,Reinhardt Katarina,Hollink Iris H,Klusmann Jan-Henning,Lehrnbecher Thomas,Roettgers Silja,Stary Jan,Dworzak Michael,Welte Karl,Creutzig Ursula,Reinhardt Dirk Journal of clinical oncology : official journal of the American Society of Clinical Oncology PURPOSE:This prospective, multicenter Acute Myeloid Leukemia Berlin-Frankfurt-Muenster (AML-BFM) 98 study randomly tested the ability of granulocyte colony-stimulating factor (G-CSF) to reduce infectious complications and to improve outcomes in children and adolescents with acute myeloid leukemia (AML). However, a trend toward an increased incidence of relapses in the standard-risk (SR) group after G-CSF treatment was observed. PATIENTS AND METHODS:Of 154 SR patients in the AML-BFM 98 cohort, 50 patients were tested for G-CSF receptor (G-CSFR) RNA isoform I and IV expression, G-CSFR cell surface expression, and acquired mutations in the G-CSFR gene. RESULTS:In patients randomly assigned to receive G-CSF after induction, 16 patients overexpressing the G-CSFR isoform IV showed an increased 5-year cumulative incidence of relapse (50% +/- 13%) compared with 14 patients with low-level isoform IV expression (14% +/- 10%; log-rank P = .04). The level of G-CSFR isoform IV had no significant effect in patients not receiving G-CSF (P = .19). Multivariate analyses of the G-CSF-treated subgroup, including the parameters G-CSFR isoform IV overexpression, sex, and favorable cytogenetics as covariables, revealed the prognostic relevance of G-CSFR isoform IV overexpression for 5-year event-free survival (P = .031) and the 5-year cumulative incidence of relapse (P = .049). CONCLUSION:Our results demonstrate that children and adolescents with AMLs that overexpress the differentiation-defective G-CSFR isoform IV respond to G-CSF administration after induction, but with a significantly higher incidence of relapse. 10.1200/JCO.2009.25.9010
    Chemo-genomic interrogation of CEBPA mutated AML reveals recurrent CSF3R mutations and subgroup sensitivity to JAK inhibitors. Lavallée Vincent-Philippe,Krosl Jana,Lemieux Sébastien,Boucher Geneviève,Gendron Patrick,Pabst Caroline,Boivin Isabel,Marinier Anne,Guidos Cynthia J,Meloche Sylvain,Hébert Josée,Sauvageau Guy Blood In this study, we analyzed RNA-sequencing data of 14 samples characterized by biallelic CEBPA (CEBPA(bi)) mutations included in the Leucegene collection of 415 primary acute myeloid leukemia (AML) specimens, and describe for the first time high frequency recurrent mutations in the granulocyte colony-stimulating factor receptor gene CSF3R, which signals through JAK-STAT proteins. Chemical interrogation of these primary human specimens revealed a uniform and specific sensitivity to all JAK inhibitors tested irrespective of their CSF3R mutation status, indicating a general sensitization of JAK-STAT signaling in this leukemia subset. Altogether, these results identified the co-occurrence of mutations in CSF3R and CEBPA in a well-defined AML subset, which uniformly responds to JAK inhibitors and paves the way to personalized clinical trials for this disease. 10.1182/blood-2016-03-705053
    G-CSF induced reactive oxygen species involves Lyn-PI3-kinase-Akt and contributes to myeloid cell growth. Zhu Quan-Sheng,Xia Ling,Mills Gordon B,Lowell Clifford A,Touw Ivo P,Corey Seth J Blood Granulocyte colony-stimulating factor (G-CSF) drives the production, survival, differentiation, and inflammatory functions of granulocytes. Reactive oxygen species (ROSs) provide a major thrust of the inflammatory response, though excessive ROSs may be deleterious. G-CSF stimulation showed a time- and dose-dependent increase in ROS production, correlating with activation of Lyn and Akt. Inhibition of Lyn, PI3-kinase, and Akt abrogated G-CSF-induced ROS production. This was also blocked by DPI, a specific inhibitor of NADPH oxidase. Following G-CSF stimulation, neutrophils from Lyn-/- mice produced less ROSs than wild-type littermates. G-CSF induced both serine phosphorylation and membrane translocation of p47phox, a subunit of NADPH oxidase. Because patients with a truncated G-CSF receptor have a high risk of developing acute myeloid leukemia (AML), we hypothesized that dysregulation of ROSs contributes to leukemogenesis. Cells expressing the truncated G-CSF receptor produced more ROSs than those with the full-length receptor. G-CSF-induced ROS production was enhanced in bone marrow-derived neutrophils expressing G-CSFRdelta715, a truncated receptor. The antioxidant N-acetyl-L-cysteine diminished G-CSF-induced ROS production and cell proliferation by inhibiting Akt activation. These data suggest that the G-CSF-induced Lyn-PI3K-Akt pathway drives ROS production. One beneficial effect of therapeutic targeting of Lyn-PI3K-kinase-Akt cascade is abrogating ROS production. 10.1182/blood-2005-04-1612
    Negative effects of GM-CSF signaling in a murine model of t(8;21)-induced leukemia. Matsuura Shinobu,Yan Ming,Lo Miao-Chia,Ahn Eun-Young,Weng Stephanie,Dangoor David,Matin Mahan,Higashi Tsunehito,Feng Gen-Sheng,Zhang Dong-Er Blood The t(8;21)(q22;q22) is common in adult acute myeloid leukemia (AML). The RUNX1-ETO fusion protein that is expressed by this translocation is poorly leukemogenic and requires additional mutations for transformation. Loss of sex chromosome (LOS) is frequently observed in t(8;21) AML. In the present study, to evaluate whether LOS cooperates with t(8;21) in leukemogenesis, we first used a retroviral transduction/transplantation model to express RUNX1-ETO in hematopoietic cells from XO mice. The low frequency of leukemia in these mice suggests that the potentially critical gene for suppression of t(8;21) leukemia in humans is not conserved on mouse sex chromosomes. The gene encoding the GM-CSF receptor α subunit (CSF2RA) is located on X and Y chromosomes in humans but on chromosome 19 in mice. GM-CSF promotes myeloid cell survival, proliferation, and differentiation. To determine whether GM-CSF signaling affects RUNX1-ETO leukemogenesis, hematopoietic stem/progenitor cells that lack GM-CSF signaling were used to express RUNX1-ETO and transplanted into lethally irradiated mice, and a high penetrance of AML was observed in recipients. Furthermore, GM-CSF reduced the replating ability of RUNX1-ETO-expressing cells. These results suggest a possible tumor-suppressor role of GM-CSF in RUNX1-ETO leukemia. Loss of the CSF2RA gene may be a critical mutation explaining the high incidence of LOS associated with the t(8;21)(q22;q22) translocation. 10.1182/blood-2011-04-350694
    AML1-MTG8 leukemic protein induces the expression of granulocyte colony-stimulating factor (G-CSF) receptor through the up-regulation of CCAAT/enhancer binding protein epsilon. Shimizu K,Kitabayashi I,Kamada N,Abe T,Maseki N,Suzukawa K,Ohki M Blood The t(8;21) translocation is one of the most frequent chromosomal abnormalities associated with acute myeloid leukemia (AML). In this translocation, the AML1 (CBFA2/PEBP2aB) gene is disrupted and fused to the MTG8 (ETO) gene. The ectopic expression of the resulting AML1-MTG8 fusion gene product in L-G and 32Dcl3 murine myeloid precursor cells stimulates cell proliferation without inducing morphologic terminal differentiation into mature granulocytes in response to granulocyte-colony stimulating factor (G-CSF). This study found that the ectopic expression of AML1-MTG8 elevates the expression of the G-CSF receptor (G-CSFR). Analysis of the promoter region of the G-CSFR gene revealed that up-regulation of G-CSFR expression by AML1-MTG8 does not depend on the AML1-binding sequence, but on the C/EBP (CCAAT/enhancer binding protein) binding site. The results suggest that the overproduction of G-CSFR is at least partly mediated by C/EBPepsilon, whose expression is activated by AML1-MTG8. The ectopic expression of G-CSFR in L-G cells induced cell proliferation in response to G-CSF, but did not inhibit cell differentiation into mature neutrophils. Overexpression of C/EBPepsilon in L-G cells also stimulated G-CSF-dependent cell proliferation. High expression levels of G-CSFR were also found in the leukemic cells of AML patients with t(8;21). Therefore, G-CSF-dependent cell proliferation of myeloid precursor cells may be implicated in leukemogenesis.
    Time course of increasing numbers of mutations in the granulocyte colony-stimulating factor receptor gene in a patient with congenital neutropenia who developed leukemia. Tschan C A,Pilz C,Zeidler C,Welte K,Germeshausen M Blood Point mutations in the granulocyte colony-stimulating factor receptor (G-CSFR) gene have been linked to the development of secondary leukemia in patients with congenital neutropenia (CN). This report presents data on a now 18-year-old patient with CN who has received G-CSF treatment since 1989 and who developed acute myeloid leukemia (AML) in 1998. To evaluate whether there is an association between the occurrence of point mutations of the G-CSFR gene and development of secondary AML, DNA/messenger RNA of neutrophils and mononuclear cells from this patient were analyzed at different time points by polymerase chain reaction and subsequent cloning by DNA sequencing of representative numbers of individual clones. Findings suggest an increasing instability of the G-CSFR gene in time as judged by increasing numbers of mutations proposed to be one important step in the development of AML in this patient. 10.1182/blood.v97.6.1882
    CSF1R inhibitors exhibit antitumor activity in acute myeloid leukemia by blocking paracrine signals from support cells. Edwards David K,Watanabe-Smith Kevin,Rofelty Angela,Damnernsawad Alisa,Laderas Ted,Lamble Adam,Lind Evan F,Kaempf Andy,Mori Motomi,Rosenberg Mara,d'Almeida Amanda,Long Nicola,Agarwal Anupriya,Sweeney David Tyler,Loriaux Marc,McWeeney Shannon K,Tyner Jeffrey W Blood To identify new therapeutic targets in acute myeloid leukemia (AML), we performed small-molecule and small-interfering RNA (siRNA) screens of primary AML patient samples. In 23% of samples, we found sensitivity to inhibition of colony-stimulating factor 1 (CSF1) receptor (CSF1R), a receptor tyrosine kinase responsible for survival, proliferation, and differentiation of myeloid-lineage cells. Sensitivity to CSF1R inhibitor GW-2580 was found preferentially in de novo and favorable-risk patients, and resistance to GW-2580 was associated with reduced overall survival. Using flow cytometry, we discovered that CSF1R is not expressed on the majority of leukemic blasts but instead on a subpopulation of supportive cells. Comparison of CSF1R-expressing cells in AML vs healthy donors by mass cytometry revealed expression of unique cell-surface markers. The quantity of CSF1R-expressing cells correlated with GW-2580 sensitivity. Exposure of primary AML patient samples to a panel of recombinant cytokines revealed that CSF1R inhibitor sensitivity correlated with a growth response to CSF1R ligand, CSF1, and other cytokines, including hepatocyte growth factor (HGF). The addition of CSF1 increased the secretion of HGF and other cytokines in conditioned media from AML patient samples, whereas adding GW-2580 reduced their secretion. In untreated cells, HGF levels correlated significantly with GW-2580 sensitivity. Finally, recombinant HGF and HS-5-conditioned media rescued cell viability after GW-2580 treatment in AML patient samples. Our results suggest that CSF1R-expressing cells support the bulk leukemia population through the secretion of HGF and other cytokines. This study identifies CSF1R as a novel therapeutic target of AML and provides a mechanism of paracrine cytokine/growth factor signaling in this disease. 10.1182/blood-2018-03-838946
    G-CSF and its receptor in myeloid malignancy. Beekman Renée,Touw Ivo P Blood Granulocyte colony-stimulating factor (G-CSF) has been used in the clinic for more than 2 decades to treat congenital and acquired neutropenias and to reduce febrile neutropenia before or during courses of intensive cytoreductive therapy. In addition, healthy stem cell donors receive short-term treatment with G-CSF for mobilization of hematopoietic stem cells. G-CSF has also been applied in priming strategies designed to enhance the sensitivity of leukemia stem cells to cytotoxic agents, in protocols aimed to induce their differentiation and accompanying growth arrest and cell death, and in severe aplastic anemia and myelodysplastic syndrome (MDS) to alleviate anemia. The potential adverse effects of G-CSF administration, particularly the risk of malignant transformation, have fueled ongoing debates, some of which can only be settled in follow-up studies extending over several decades. This specifically applies to children with severe congenital neutropenia who receive lifelong treatment with G-CSF and in which the high susceptibility to develop MDS and acute myeloid leukemia (AML) has now become a major clinical concern. Here, we will highlight some of the controversies and challenges regarding the clinical application of G-CSF and discuss a possible role of G-CSF in malignant transformation, particularly in patients with neutropenia harboring mutations in the gene encoding the G-CSF receptor. 10.1182/blood-2010-01-234120
    Inhibition of granulocyte colony-stimulating factor-mediated myeloid maturation by low level expression of the differentiation-defective class IV granulocyte colony-stimulating factor receptor isoform. White S M,Alarcon M H,Tweardy D J Blood In acute myeloid leukemia (AML), granulocyte colony-stimulating factor receptor (G-CSFR) proliferative and maturational signaling pathways are uncoupled. Seven human G-CSFR mRNA isoforms exist, named class I through class VII. The 183-amino acid cytosolic domain of the class I isoform provides all signaling activities. The class IV isoform is "differentiation defective" because the carboxy-terminal 87 amino acids are replaced with 34 amino acids of novel sequence. In more than 50% of AML samples, the class IV/class I G-CSFR mRNA ratio is aberrantly elevated compared to normal CD34(+) bone marrow cells. We hypothesized that the increased relative expression of class IV G-CSFR in AML uncouples proliferative and maturational G-CSFR signaling pathways. To test this, we transfected the G-CSF-responsive murine cell line 32Dcl3 with class IV G-CSFR cDNA. After 10 days of G-CSF stimulation, clones expressing class IV G-CSFR had greater percentages of myeloblasts and promyelocytes than controls (53% +/- 13% versus 3% +/- 2%). Differential counts over time demonstrated delayed G-CSF-driven maturation in 5 class IV-expressing clones, with 2 clones demonstrating a subpopulation that completely failed to differentiate. Heterologous class IV expression did not affect G-CSF-dependent proliferation. Class IV/murine G-CSFR mRNA ratios after 24 hours of G-CSF stimulation for 3 of the 5 clones (range, 0. 090 to 0.245; mean, 0.152 +/- 0.055) are within the range of class IV/class I mRNA ratios seen in patients with AML. This indicates that aberrantly increased relative class IV G-CSFR expression seen in AML can uncouple G-CSFR proliferative and maturational signaling pathways.
    G-CSF receptor truncations found in SCN/AML relieve SOCS3-controlled inhibition of STAT5 but leave suppression of STAT3 intact. van de Geijn Gert-Jan M,Gits Judith,Aarts Lambertus H J,Heijmans-Antonissen Claudia,Touw Ivo P Blood Truncated granulocyte colony-stimulating factor receptors (G-CSF-Rs) are implicated in severe congenital neutropenia (SCN) and the consecutive development of acute myeloid leukemia (AML). Mice expressing G-CSF-R truncation mutants (gcsfr-d715) show defective receptor internalization, an increased signal transducer and activator of transcription 5 (STAT5)/STAT3 activation ratio, and hyperproliferative responses to G-CSF treatment. We determined whether a lack of negative feedback by suppressor of cytokine signaling (SOCS) proteins contributes to the signaling abnormalities of G-CSF-R-d715. Expression of SOCS3 transcripts in bone marrow cells from G-CSF-treated gcsfr-d715 mice was approximately 60% lower than in wild-type (WT) littermates. SOCS3 efficiently suppressed STAT3 and STAT5 activation by WT G-CSF-R in luciferase reporter assays. In contrast, while SOCS3 still inhibited STAT3 activation by G-CSF-R-d715, STAT5 activation was no longer affected. This was due mainly to loss of the SOCS3 recruitment site Tyr729, with an additional contribution of the internalization defects of G-CSF-R-d715. Because Tyr729 is also a docking site for the Src homology 2-containing protein tyrosine phosphatase-2 (SHP-2), which binds to and inactivates STAT5, we suggest a model in which reduced SOCS3 expression, combined with the loss of recruitment of both SOCS3 and SHP-2 to the activated receptor complex, determine the increased STAT5/STAT3 activation ratio and the resulting signaling abnormalities projected by truncated G-CSF-R mutants. 10.1182/blood-2003-08-2913
    An activating mutation in the transmembrane domain of the granulocyte colony-stimulating factor receptor in patients with acute myeloid leukemia. Forbes Louisa V,Gale Rosemary E,Pizzey Arnold,Pouwels Karin,Nathwani Amit,Linch David C Oncogene To date, constitutively activating point mutations reported in hematopoietic growth factor receptors in patients with acute myeloid leukemia (AML) have been restricted to receptors with intrinsic tyrosine kinase activity such as c-kit and FLT3. We describe here a Thr617Asn mutation in the transmembrane domain of the non-tyrosine kinase receptor for granulocyte colony-stimulating factor (G-CSF) in the blast cells of two out of 555 AML patients examined. The mutant receptor conferred growth factor independence on factor-dependent Ba/F3 cells. In the absence of ligand, immunoblotting showed weak phosphorylation of JAK2, STAT3, ERKs 1 and 2 and the receptor itself, and there was approximately 70% of maximal growth in a proliferation assay. All signals were significantly enhanced in the presence of G-CSF. Retroviral transduction of mutant receptor into primary hematopoietic CD34+ cells induced G-CSF independent myeloid differentiation as assessed by the development of neutrophils and surface expression of CD11b and CD14. These results confirm the importance of the transmembrane domain for receptor function and suggest that introduction of an asparagine residue can cause sufficient stabilization of helix-helix interactions in the absence of ligand to activate downstream signaling pathways involved in directing proliferation and differentiation. 10.1038/sj.onc.1205767
    Maxson JE, Ries RE, Wang Y-C, et al. CSF3R mutations have a high degree of overlap with CEBPA mutations in pediatric AML. Blood. 2016;127(24):3094-3098. Blood 10.1182/blood-2016-11-751834
    CSF3R mutations have a high degree of overlap with CEBPA mutations in pediatric AML. Maxson Julia E,Ries Rhonda E,Wang Yi-Cheng,Gerbing Robert B,Kolb E Anders,Thompson Sarah L,Guidry Auvil Jaime M,Marra Marco A,Ma Yussanne,Zong Zusheng,Mungall Andrew J,Moore Richard,Long William,Gesuwan Patee,Davidsen Tanja M,Hermida Leandro C,Hughes Seamus B,Farrar Jason E,Radich Jerald P,Smith Malcolm A,Gerhard Daniela S,Gamis Alan S,Alonzo Todd A,Meshinchi Soheil Blood 10.1182/blood-2016-04-709899
    Two cases of cyclic neutropenia with acquired CSF3R mutations, with 1 developing AML. Klimiankou Maksim,Mellor-Heineke Sabine,Klimenkova Olga,Reinel Elisa,Uenalan Murat,Kandabarau Siarhei,Skokowa Julia,Welte Karl,Zeidler Cornelia Blood 10.1182/blood-2015-12-685784
    CSF3R and CALR mutations in paediatric myeloid disorders and the association of CSF3R mutations with translocations, including t(8; 21). Sano Hitoshi,Ohki Kentaro,Park Myoung-Ja,Shiba Norio,Hara Yusuke,Sotomatsu Manabu,Tomizawa Daisuke,Taga Takashi,Kiyokawa Nobutaka,Tawa Akio,Horibe Keizo,Adachi Souichi,Hayashi Yasuhide British journal of haematology Mutations in the colony-stimulating factor 3 receptor (CSF3R) and calreticulin (CALR) genes have been reported in a proportion of adults with myeloproliferative disease. However, little is known about CSF3R or CALR mutations in paediatric myeloid disorders. We analysed CSF3R exons 14 and 17, and CALR exon 9, using direct sequencing in samples of paediatric acute myeloid leukaemia (AML; n = 521), juvenile myelomonocytic leukaemia (JMML; n = 40), myelodysplastic syndrome (MDS; n = 20) and essential thrombocythaemia (ET; n = 21). CSF3R mutations were found in 10 (1.2%) of 521 patients with AML; two in exon 14 (both missense mutations resulting in p.T618I) and eight in exon 17 (three frameshift mutations: p.S715X, p.Q774R, and p.S783Q; and five novel missense mutations: p.Q754K, p.R769H, p.L777F, p.T781I, and S795R). All of the patients with mutations in CSF3R exon 17 had chromosomal translocations, including four with t(8;21). At the time of reporting, seven of these ten patients are alive; three have died, due to side effects of chemotherapy. No CSF3R mutations were found in cases of MDS, JMML or ET. The only mutation found in the CALR gene was a frameshift (p.L367 fs) in one ET patient. We discuss the potential impact of these findings for the leukaemogenesis and clinical features of paediatric myeloid disorders. 10.1111/bjh.13439
    E6AP inhibits G-CSFR turnover and functions by promoting its ubiquitin-dependent proteasome degradation. Chhabra Stuti,Kumar Yogesh,Thacker Gatha,Kapoor Isha,Lochab Savita,Sanyal Sabyasachi,Bhatt Madan L B,Chattopadhyay Naibedya,Trivedi Arun Kumar Biochimica et biophysica acta. Molecular cell research Granulocyte colony-stimulating factor receptor (G-CSFR) plays a crucial role in regulating myeloid cell survival, proliferation, and neutrophilic granulocyte precursor cells maturation. Previously, we demonstrated that Fbw7α negatively regulates G-CSFR and its downstream signaling through ubiquitin-proteasome mediated degradation. However, whether additional ubiquitin ligases for G-CSFR exist is not known. Identifying multiple E3 ubiquitin ligases for G-CSFR shall improve our understanding of activation and subsequent attenuation of G-CSFR signaling required for differentiation and proliferation. Here, for the first time we demonstrate that E6 associated protein (E6AP), an E3 ubiquitin ligase physically associates with G-CSFR and targets it for ubiquitin-mediated proteasome degradation and thereby attenuates its functions. We further show that E6AP promoted G-CSFR degradation leads to reduced phosphorylation of signal transducer and activator of transcription 3 (STAT3) which is required for G-CSF dependent granulocytic differentiation. More importantly, our finding shows that E6AP also targets mutant form of G-SCFR (G-CSFR-T718), frequently observed in severe congenital neutropenia (SCN) patients that very often culminate to AML, however, at a quite slower rate than wild type G-CSFR. In addition, our data showed that knockdown of E6AP restores G-CSFR and its signaling thereby promoting granulocytic differentiation. Collectively, our data demonstrates that E6AP facilitates ubiquitination and subsequent degradation of G-CSFR leading to attenuation of its downstream signaling and inhibition of granulocytic differentiation. 10.1016/j.bbamcr.2017.05.026
    G-CSF receptor (CSF3R) mutations in X-linked neutropenia evolving to acute myeloid leukemia or myelodysplasia. Beel Karolien,Vandenberghe Peter Haematologica X-linked neutropenia (XLN) is a rare form of Congenital Neutropenia (CN) caused by inherited gain-of-function mutations of WAS. Here we report 2 cases of the original L270P X-linked neutropenia kindred that evolved to MDS or AML, with acquisition of G-CSFR (CSF3R) mutations and monosomy 7. Thus, leukemic transformation with acquisition of CSF3R mutations and monosomy 7 is not restricted to classical congenital neutropenia with autosomal inheritance, but can also occur in other genotypes of inherited neutropenia. 10.3324/haematol.2009.009001
    Altered expression of CSF3R splice variants impacts signal response and is associated with SRSF2 mutations. Lance Amanda,Druhan Lawrence J,Vestal C Greer,Steuerwald Nury M,Hamilton Alicia,Smith Mathew,Price Andrea,Tjaden Elise,Fox Andee N,Avalos Belinda R Leukemia Three annotated CSF3R mRNA splice variants have been described. CSF3R-V1 is the wild-type receptor, while CSF3R-V4 is a truncated form increased in some patients with AML. CSF3R-V3 mRNA was identified in placenta more than 20 years ago, but remains largely uncharacterized due to the lack of a suitable detection assay. Using a novel digital PCR method to quantitate expression of each CSF3R mRNA splice variant in hematopoietic cells, CSF3R-V1 was most highly expressed followed by CSF3R-V3. Functional assays revealed expression of V3 alone conferred a hypoproliferative phenotype associated with defective JAK-STAT activation. However, coexpression of V1 with V3 rescued proliferative responses. Comparative analysis of V3/V1 expression in CD34+ cells from healthy donors and patients with AML revealed a statistically significant increase in the V3/V1 ratio only in the subset of patients with AML harboring SRSF2 mutations. Knockout of SRFS2 in KG-1 and normal CD34+ cells decreased the V3/V1 ratio. Collectively, these data are the first to demonstrate expression of the CSF3R-V3 splice variant in primary human myeloid cells and a role for SRSF2 in modulating CSF3R splicing. Our findings provide confirmatory evidence that CSF3R is a target of SRSF2 mutations, which has implications for novel treatment strategies for SRSF2-mutated myeloid malignancies. 10.1038/s41375-019-0567-9
    Alternatively spliced, truncated GCSF receptor promotes leukemogenic properties and sensitivity to JAK inhibition. Mehta H M,Futami M,Glaubach T,Lee D W,Andolina J R,Yang Q,Whichard Z,Quinn M,Lu H F,Kao W M,Przychodzen B,Sarkar C A,Minella A,Maciejewski J P,Corey S J Leukemia Granulocyte colony-stimulating factor (GCSF) drives the production of myeloid progenitor and precursor cells toward neutrophils via the GCSF receptor (GCSFR, gene name CSF3R). Children with severe congenital neutropenia chronically receive pharmacologic doses of GCSF, and ∼30% will develop myelodysplasia/acute myeloid leukemia (AML) associated with GCSFR truncation mutations. In addition to mutations, multiple isoforms of CSF3R have also been reported. We found elevated expression of the alternatively spliced isoform, class IV CSF3R in adult myelodysplastic syndrome/AML patients. Aside from its association with monosomy 7 and higher rates of relapse in pediatric AML patients, little is known about the biology of the class IV isoform. We found developmental regulation of CSF3R isoforms with the class IV expression more representative of a progenitor cell stage. Striking differences were found in phosphoprotein signaling involving Janus kinase (JAK)-signal transducer and activator of transcription (STAT) and cell cycle gene expression. Enhanced proliferation by class IV GCSFR was associated with diminished STAT3 and STAT5 activation, yet showed sensitivity to JAK2 inhibitors. Alterations in the C-terminal domain of the GCSFR result in leukemic properties of enhanced growth, impaired differentiation and resistance to apoptosis, suggesting that they can behave as oncogenic drivers, sensitive to JAK2 inhibition. 10.1038/leu.2013.321
    Combined inhibition of JAK/STAT pathway and lysine-specific demethylase 1 as a therapeutic strategy in CSF3R/CEBPA mutant acute myeloid leukemia. Braun Theodore P,Coblentz Cody,Smith Brittany M,Coleman Daniel J,Schonrock Zachary,Carratt Sarah A,Callahan Rowan L,Maniaci Breanna,Druker Brian J,Maxson Julia E Proceedings of the National Academy of Sciences of the United States of America Acute myeloid leukemia (AML) is a deadly hematologic malignancy with poor prognosis, particularly in the elderly. Even among individuals with favorable-risk disease, approximately half will relapse with conventional therapy. In this clinical circumstance, the determinants of relapse are unclear, and there are no therapeutic interventions that can prevent recurrent disease. Mutations in the transcription factor CEBPA are associated with favorable risk in AML. However, mutations in the growth factor receptor CSF3R are commonly co-occurrent in CEBPA mutant AML and are associated with an increased risk of relapse. To develop therapeutic strategies for this disease subset, we performed medium-throughput drug screening on CEBPA/CSF3R mutant leukemia cells and identified sensitivity to inhibitors of lysine-specific demethylase 1 (LSD1). Treatment of CSF3R/CEBPA mutant leukemia cells with LSD1 inhibitors reactivates differentiation-associated enhancers driving immunophenotypic and morphologic differentiation. LSD1 inhibition is ineffective as monotherapy but demonstrates synergy with inhibitors of JAK/STAT signaling, doubling median survival in vivo. These results demonstrate that combined inhibition of JAK/STAT signaling and LSD1 is a promising therapeutic strategy for CEBPA/CSF3R mutant AML. 10.1073/pnas.1918307117
    CSF3R Mutations are frequently associated with abnormalities of RUNX1, CBFB, CEBPA, and NPM1 genes in acute myeloid leukemia. Zhang Yang,Wang Fang,Chen Xue,Zhang Yu,Wang Mingyu,Liu Hong,Cao Panxiang,Ma Xiaoli,Wang Tong,Zhang Jianping,Zhang Xian,Lu Peihua,Liu Hongxing Cancer BACKGROUND:Mutations in the colony-stimulating factor 3 receptor (CSF3R) gene occur frequently in chronic neutrophilic leukemia and are rare in de novo acute leukemia. The objective of this study was to assess the incidence of CSF3R mutations in acute leukemia and their association with other genetic abnormalities. METHODS:Amplicon-targeted, next-generation sequencing of 58 genes was performed retrospectively on 1152 patients (acute myeloid leukemia [AML], n = 587; acute lymphoid leukemia [ALL], n = 565). Reverse transcriptase-polymerase chain reaction analysis was used to detect 35 leukemia-specific gene fusions. RESULTS:CSF3R mutations (26 patients) were detected in 3.6% (13 of 364 patients), 4.6% (8 of 175 patients), and 8.3% (4 of 48 patients) of those with de novo, relapsed, and secondary AML, respectively, and in 0.2% (1 of 565 patients) of those with ALL. In total, 9 distinct CSF3R mutations were detected. Membrane-proximal missense mutations and cytoplasmic truncations were identified as mutually exclusive. The proportion of patients who had French-American-British subtypes M2 and M4 in the CSF3R-mutated group was significantly greater than that in the CSF3R wild-type group for both the de novo AML cohort (P = .001) and the relapsed AML cohort (P = .024). All de novo and relapsed AMLs with CSF3R mutations were associated with genetic alterations in transcription factors, including RUNX1-RUNX1T1, CBFB-MYH11, double-mutated CCAAT/enhancer binding protein α (CEBPAdm), and NPM1 mutations; and core-binding factor gene abnormalities and CEBPAdm accounted for 90.5% (19 of 21 patients). CONCLUSIONS:CSF3R mutations are uncommon in AML; however, when they occur, they are often associated with core-binding factor gene abnormalities and CEBPAdm. An in-depth understanding of the interaction between these genetic alterations could facilitate a clearer understanding of the role of CSF3R mutations in AML development and may be used for disease classification, prognosis, and the development of targeted therapy. 10.1002/cncr.31586
    Expression and functional analysis of granulocyte colony-stimulating factor receptors on CD34++ cells in patients with myelodysplastic syndrome (MDS) and MDS-acute myeloid leukaemia. Sultana Tanvira Afroze,Harada Hironori,Ito Kinro,Tanaka Hideo,Kyo Taiichi,Kimura Akiro British journal of haematology CD34++ cells from 45 patients with myelodysplastic syndrome (MDS) and MDS-acute myeloid leukaemia (MDS-AML) were observed by flow cytometry for the expression of granulocyte colony-stimulating factor receptor (G-CSFR). Ten patients had a significantly reduced expression of G-CSFR. Late stages of disease showed a higher proportion of either high or low G-CSFR expression than earlier stages. In MDS refractory anaemia (RA), G-CSFR was inversely related to CD33 expression. Most patients (9/10) with low G-CSFR expression had neutropenia of the peripheral blood. Neutropenia was less common in the normal group, but also occurred in the high expression group. No neutrophil response was observed following G-CSF administration to MDS-AML patients (6/6) with low G-CSFR expression. In the high expression group, patients (3/3) showed a response to G-CSF while, in the normal group (1/2), the response was minor. In the normal- or high-receptor-expressing groups, the receptors were functionally active in terms of apoptosis but not proliferation and clonogenic growth, although no clear correlation to receptor expression was observed. The G-CSFR signal transduction pathway in the normal and high group was not deficient of messenger RNA for either janus kinases (Jaks) or signal transducers and activators of transcription (Stats). These findings suggest that the lowered expression of G-CSFR may cause neutropenia in MDS and MDS-AML patients and, therefore, may partially explain the neutropenia in myelodysplastic patients. 10.1046/j.1365-2141.2003.04261.x
    miR-155 is associated with the leukemogenic potential of the class IV granulocyte colony-stimulating factor receptor in CD34⁺ progenitor cells. Zhang HaiJiao,Goudeva Lilia,Immenschuh Stephan,Schambach Axel,Skokowa Julia,Eiz-Vesper Britta,Blasczyk Rainer,Figueiredo Constança Molecular medicine (Cambridge, Mass.) Granulocyte colony-stimulating factor (G-CSF) is a major regulator of granulopoiesis on engagement with the G-CSF receptor (G-CSFR). The truncated, alternatively spliced, class IV G-CSFR (G-CSFRIV) has been associated with defective differentiation and relapse risk in pediatric acute myeloid leukemia (AML) patients. However, the detailed biological properties of G-CSFRIV in human CD34(+) hematopoietic stem and progenitor cells (HSPCs) and the potential leukemogenic mechanism of this receptor remain poorly understood. In the present study, we observed that G-CSFRIV-overexpressing (G-CSFRIV(+)) HSPCs demonstrated an enhanced proliferative and survival capacity on G-CSF stimulation. Cell cycle analyses showed a higher frequency of G-CSFRIV(+) cells in the S and G2/M phase. Also, apoptosis rates were significantly lower in G-CSFRIV(+) HSPCs. These findings were shown to be associated with a sustained Stat5 activation and elevated miR-155 expression. In addition, G-CSF showed to further induce G-CSFRIV and miR-155 expression of peripheral blood mononuclear cells isolated from AML patients. A Stat5 pharmacological inhibitor or ribonucleic acid (RNA) interference-mediated silencing of the expression of miR-155 abrogated the aberrant proliferative capacity of the G-CSFRIV(+) HSPCs. Hence, the dysregulation of Stat5/miR-155 pathway in the G-CSFRIV(+) HSPCs supports their leukemogenic potential. Specific miRNA silencing or the inhibition of Stat5-associated pathways might contribute to preventing the risk of leukemogenesis in G-CSFRIV(+) HSPCs. This study may promote the development of a personalized effective antileukemia therapy, in particular for the patients exhibiting higher expression levels of G-CSFRIV, and further highlights the necessity of pre-screening the patients for G-CSFR isoforms expression patterns before G-CSF administration. 10.2119/molmed.2014.00146
    Ultra-Sensitive Deep Sequencing in Patients With Severe Congenital Neutropenia. Klimiankou Maksim,Uenalan Murat,Kandabarau Siarhei,Nustede Rainer,Steiert Ingeborg,Mellor-Heineke Sabine,Zeidler Cornelia,Skokowa Julia,Welte Karl Frontiers in immunology High frequency of acquired (colony stimulating factor 3 receptor, granulocyte) mutations has been described in patients with severe congenital neutropenia (CN) at pre-leukemia stage and overt acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Here, we report the establishment of an ultra-sensitive deep sequencing of a segment encoding the intracellular "critical region" of the G-CSFR known to be mutated in CN-MDS/AML patients. Using this method, we achieved a mutant allele frequency (MAF) detection rate of 0.01%. We detected mutations in CN patients with different genetic backgrounds, but not in patients with other types of bone marrow failure syndromes chronically treated with G-CSF (e.g., Shwachman-Diamond Syndrome). Comparison of deep sequencing results of DNA and cDNA from the bone marrow and peripheral blood cells revealed the highest sensitivity of cDNA from the peripheral blood polymorphonuclear neutrophils. This approach enables the identification of low-frequency mutant clones, increases sensitivity, and earlier detection of mutations acquired during the course of leukemogenic evolution of pre-leukemia HSCs of CN patients. We suggest application of sequencing of the entire CSF3R gene at diagnosis to identify patients with inherited lost-of-function mutations and annual ultra-deep sequencing of the critical region of to monitor acquisition of mutations. 10.3389/fimmu.2019.00116
    A truncation mutant of Csf3r cooperates with PML-RARα to induce acute myeloid leukemia in mice. Kunter Ghada,Woloszynek Jill R,Link Daniel C Experimental hematology Severe congenital neutropenia is associated with a marked propensity to develop myelodysplasia or acute myeloid leukemia (AML). Truncation mutations of CSF3R, encoding the granulocyte colony-stimulating factor receptor (G-CSFR), are associated with development of myelodysplasia/AML in severe congenital neutropenia. However, a causal relationship between CSF3R mutations and leukemic transformation has not been established. Herein, we show that truncated G-CSFR cooperates with the PML-RARα oncogene to induce AML in mice. Expression of truncated G-CSFR significantly shortens the latency of AML in a G-CSF-dependent fashion and it is associated with a distinct AML presentation characterized by higher blast counts and more severe myelosuppression. Basal and G-CSF-induced signal transducer and activator of transcription 3, signal transducer and activator of transcription 5, and extracellular signal-regulated kinase 1/2 phosphorylation were highly variable but similar in leukemic blasts expressing wild-type and truncated G-CSFR. These data provide new evidence suggesting a causative role for CSF3R mutations in human AML. 10.1016/j.exphem.2011.08.013
    Prevalence and impact of colony stimulating factor 3 receptor (CSF3R) mutations among Egyptian acute myeloid leukemia patients. Aref Salah,El-Ghonemy Mohamed,Abouzeid Tarek,El-Sabbagh Amr,El-Baiomy Mohamed Leukemia research Granulocyte-colony stimulating factor receptor (G-CSFR) mutations have been implicated in the progression of severe congenital neutropenia (SCN) to leukemia. This study aimed to investigate the prevalence of colony stimulating factor 3 receptor (CSF3R) mutations among Egyptian acute myeloid leukemia and their clinic-pathological impact. The study was conducted on 179 adult patients (156 de novo AML and 23 secondary AML on top of SCN). CSF3R mutations were analyzed by sequencing of the PCR products. CSF3R mutations were detected in 2 cases out of 156 de novo AML patients (1.2%) and eighteen cases out of 23 secondary AML patients (78.2%). It was noticed that most of the mutant cases are of younger age, have a high white blood cells count, high bone marrow blasts, bad performance status, and absence of extra medullary disease and with low rate induction remission. Also the overall survival of AML patient's secondary to CSF3R mutations was shorter as compared to those with wild type AML cases. In conclusion the frequency of CSF3R mutations is highly prevalent among AML patients secondary to SCN compared to de novo AML. 10.1016/j.leukres.2014.03.020
    Time resolved quantitative phospho-tyrosine analysis reveals Bruton's Tyrosine kinase mediated signaling downstream of the mutated granulocyte-colony stimulating factor receptors. Dwivedi Pankaj,Muench David E,Wagner Michael,Azam Mohammad,Grimes H Leighton,Greis Kenneth D Leukemia Granulocyte-colony stimulating factor receptor (G-CSFR) controls myeloid progenitor proliferation and differentiation to neutrophils. Mutations in CSF3R (encoding G-CSFR) have been reported in patients with chronic neutrophilic leukemia (CNL) and acute myeloid leukemia (AML); however, despite years of research, the malignant downstream signaling of the mutated G-CSFRs is not well understood. Here, we used a quantitative phospho-tyrosine analysis to generate a comprehensive signaling map of G-CSF induced tyrosine phosphorylation in the normal versus mutated (proximal: T618I and truncated: Q741x) G-CSFRs. Unbiased clustering and kinase enrichment analysis identified rapid induction of phospho-proteins associated with endocytosis by the wild type G-CSFR only; while G-CSFR mutants showed abnormal kinetics of canonical Stat3, Stat5, and Mapk phosphorylation, and aberrant activation of Bruton's Tyrosine Kinase (Btk). Mutant-G-CSFR-expressing cells displayed enhanced sensitivity (3-5-fold lower IC50) for ibrutinib-based chemical inhibition of Btk. Primary murine progenitor cells from G-CSFR-Q741x knock-in mice validated activation of Btk by the mutant receptor and retrovirally transduced human CD34 umbilical cord blood cells expressing mutant receptors displayed enhanced sensitivity to Ibrutinib. A significantly lower clonogenic potential was displayed by both murine and human primary cells expressing mutated receptors upon ibrutinib treatment. Finally, a dramatic synergy was observed between ibrutinib and ruxolinitib at lower dose of the individual drug. Altogether, these data demonstrate the strength of unsupervised proteomics analyses in dissecting oncogenic pathways, and suggest repositioning Ibrutinib for therapy of myeloid leukemia bearing CSF3R mutations. Phospho-tyrosine data are available via ProteomeXchange with identifier PXD009662. 10.1038/s41375-018-0188-8