Mechanisms of immune regulation in allergic diseases: the role of regulatory T and B cells.
Palomares Oscar,Akdis Mübeccel,Martín-Fontecha Mar,Akdis Cezmi A
Allergy is a major public health problem with a high socio-economic impact. The number of allergic patients is expected to reach to four billion within two decades when the World's population reaches to 10 billion. Our knowledge on the molecular mechanisms underlying allergic diseases and allergen tolerance induction had significant advances during the last years. Nowadays, it is well accepted that the generation and maintenance of allergen-specific regulatory T cells (Tregs) and regulatory B cells (Bregs) and the involvement of their suppressive cytokines and surface molecules are essential for the induction of allergen tolerance. These mechanisms play essential roles for the restoration of healthy immune responses to allergens in allergen-specific immunotherapy (AIT) and healthy immune response during high-dose antigen exposure in beekeepers and cat owners. AIT remains as the only disease-modifying and curative treatment for allergic diseases and represents a perfect model to investigate the antigen-specific immune responses in humans. A large number of clinical trials demonstrated AIT as an effective treatment in many patients, but it still faces several drawbacks in relation to efficacy, safety, long duration, and patient adherence. Novel strategies to overcome these inconveniences, such as the development of novel adjuvants and alternative routes of administration are being developed. The better understanding of the molecular mechanism governing the generation of Treg and Breg cells during allergen tolerance might well open new avenues for alternative therapeutic interventions in allergic diseases and help better understanding of other immune-tolerance-related diseases.
CD4+CD25+ regulatory T cells suppress mast cell degranulation and allergic responses through OX40-OX40L interaction.
Gri Giorgia,Piconese Silvia,Frossi Barbara,Manfroi Vanessa,Merluzzi Sonia,Tripodo Claudio,Viola Antonella,Odom Sandra,Rivera Juan,Colombo Mario P,Pucillo Carlo E
T regulatory (Treg) cells play a role in the suppression of immune responses, thus serving to induce tolerance and control autoimmunity. Here, we explored whether Treg cells influence the immediate hypersensitivity response of mast cells (MCs). Treg cells directly inhibited the FcvarepsilonRI-dependent MC degranulation through cell-cell contact involving OX40-OX40L interactions between Treg cells and MCs, respectively. When activated in the presence of Treg cells, MCs showed increased cyclic adenosine monophosphate (cAMP) concentrations and reduced Ca(2+) influx, independently of phospholipase C (PLC)-gamma2 or Ca(2+) release from intracellular stores. Antagonism of cAMP in MCs reversed the inhibitory effects of Treg cells, restoring normal Ca(2+) responses and degranulation. Importantly, the in vivo depletion or inactivation of Treg cells caused enhancement of the anaphylactic response. The demonstrated crosstalk between Treg cells and MCs defines a previously unrecognized mechanism controlling MC degranulation. Loss of this interaction may contribute to the severity of allergic responses.
Elevated histaminase (diamine oxidase) activity in small-cell carcinoma of the lung.
Baylin S B,Abeloff M D,Wieman K C,Tomford J W,Ettinger D S
The New England journal of medicine
To investigate the possible embryologic relation between small-cell carcinoma of the lung and medullary thyroid carcinoma, we measured plasma histaminase (an enzyme found in medullary carcinoma tissue) in 25 patients with small-cell tumors. The assays used histamine and putrescine as substrates. Thirty-two per cent of the patients by the histamine assay, and 31 per cent by the putrescine, had values greater than +2 S.D. from the mean for 63 normal persons. In contrast, among 20 patients with squamous and large-cell lung tumors, one (by the histamine assay), and two (by the putrescine) had elevated values. In four of five autopsy cases, histaminase was high in small-cell carcinoma tissue. The enzyme in plasma and in tumor behaved as classic histaminase in substrate specificity, and in response to inhibitors. The data support the proposed embryologic relation between small-cell lung carcinoma and medullary thyroid carcinoma, and further associate histaminase with some neural crest tumors.
Real-time RT-PCR analysis of human histidine decarboxylase, a new marker for several types of leukemia and cancer.
Melgarejo Esther,Medina Miguel Angel,Paz José Carlos,Sánchez-Jiménez Francisca,Urdiales José Luis
Histamine is involved in different physiological and pathological responses, such as immune response, gastric acid secretion or neurotransmission, as either angiogenesis or cancer. Histidine decarboxylase (HDC) catalyzes the formation of histamine from histidine. HDC has been suggested as a new marker for neuroendocrine differentiation, inflammatory pathologies and several leukemia and highly malignant forms of cancer, such as melanoma and small cell lung carcinoma. In the present work, we describe the use of Syber Green-based quantitative real-time RT-PCR to determine the expression of histidine decarboxylase in human cells and tissue. As an internal control, glyceraldehyde 3-phosphate dehydrogenase was also amplified. The linear dynamic range of the assay covered 4 orders of magnitude for HDC amplification. The detection limit was 0.1 ng of total RNA extracted from HMC-1 cells. This method is simple, rapid, sensitive, and quantitative, and allows for the specific identification of cells and tissue expressing HDC, stressing its potential diagnostic usefulness in malignancies in which HDC is described as a new marker.
Chronic Inflammation: Synergistic Interactions of Recruiting Macrophages (TAMs) and Eosinophils (Eos) with Host Mast Cells (MCs) and Tumorigenesis in CALTs. M-CSF, Suitable Biomarker for Cancer Diagnosis!
Ongoing debates, misunderstandings and controversies on the role of inflammation in cancer have been extremely costly for taxpayers and cancer patients for over four decades. A reason for repeated failed clinical trials (90% ± 5 failure rates) is heavy investment on numerous genetic mutations (molecular false-flags) in the chaotic molecular landscape of site-specific cancers which are used for "targeted" therapies or "personalized" medicine. Recently, unresolved/chronic inflammation was defined as loss of balance between two tightly regulated and biologically opposing arms of acute inflammation ("Yin"-"Yang" or immune surveillance). Chronic inflammation could differentially erode architectural integrities in host immune-privileged or immune-responsive tissues as a common denominator in initiation and progression of nearly all age-associated neurodegenerative and autoimmune diseases and/or cancer. Analyses of data on our "accidental" discoveries in 1980s on models of acute and chronic inflammatory diseases in conjunctival-associated lymphoid tissues (CALTs) demonstrated at least three stages of interactions between resident (host) and recruited immune cells: (a), acute phase; activation of mast cells (MCs), IgE Abs, histamine and prostaglandin synthesis; (b), intermediate phase; down-regulation phenomenon, exhausted/degranulated MCs, heavy eosinophils (Eos) infiltrations into epithelia and goblet cells (GCs), tissue hypertrophy and neovascularization; and (c), chronic phase; induction of lymphoid hyperplasia, activated macrophages (Mfs), increased (irregular size) B and plasma cells, loss of integrity of lymphoid tissue capsular membrane, presence of histiocytes, follicular and germinal center formation, increased ratios of local IgG1/IgG2, epithelial thickening (growth) and/or thinning (necrosis) and angiogenesis. Results are suggestive of first evidence for direct association between inflammation and identifiable phases of immune dysfunction in the direction of tumorigenesis. Activated MFs (TAMs or M2) and Eos that are recruited by tissues (e.g., conjunctiva or perhaps lung airways) whose principal resident immune cells are MCs and lymphocytes are suggested to play crucial synergistic roles in enhancing growth promoting capacities of host toward tumorigenesis. Under oxidative stress, M-CSF may produce signals that are cumulative/synergistic with host mediators (e.g., low levels of histamine), facilitating tumor-directed expression of decoy receptors and immune suppressive factors (e.g., dTNFR, IL-5, IL-10, TGF-b, PGE2). M-CSF, possessing superior sensitivity and specificity, compared with conventional markers (e.g., CA-125, CA-19-9) is potentially a suitable biomarker for cancer diagnosis and technology development. Systematic monitoring of interactions between resident and recruited cells should provide key information not only about early events in loss of immune surveillance, but it would help making informed decisions for balancing the inherent tumoricidal (Yin) and tumorigenic (Yang) properties of immune system and effective preventive and therapeutic approaches and accurate risk assessment toward improvement of public health.
Histamine airway hyper-responsiveness and mortality from chronic obstructive pulmonary disease: a cohort study.
Hospers J J,Postma D S,Rijcken B,Weiss S T,Schouten J P
Lancet (London, England)
BACKGROUND:Smoking and airway lability, which is expressed by histamine airway hyper-responsiveness, are known risk factors for development of respiratory symptoms. Smoking is also associated with increased mortality risks. We studied whether airway hyper-responsiveness is associated with increased mortality, and whether this risk was independent of smoking and reduced lung function. METHODS:We followed up 2008 inhabitants of the communities of Vlagtwedde, Vlaardingen, and Meppel (Netherlands), who had histamine challenge test data, from 1964-72 for 30 years. Follow-up was 99% successful (29 patients lost to follow-up) with 1453 participants alive and 526 deaths (246 died from cardiovascular disease, 54 from lung cancer, and 21 from chronic obstructive pulmonary disease [COPD]). FINDINGS:Mortality from COPD increased with more severe hyper-responsiveness; relative risks of 3.83 (95% CI 0.97-15.1), 4.40 (1.16-16.7), 4.78 (1.27-18.0), 6.69 (1.71-26.1), and 15.8 (3.72-67.1) were associated with histamine thresholds of 32 g/L, 16 g/L, 8 g/L, 4 g/L, and 1 g/L, respectively, compared with no hyper-responsiveness. These risks were adjusted for sex, age, smoking, lung function, body-mass index, positive skin tests, eosinophilia, asthma, and city of residence. INTERPRETATION:Increased histamine airway hyper-responsiveness predicts mortality from COPD. Although this trend was more pronounced in smokers, an increasing proportion of COPD deaths with increasing hyper-responsiveness was also present among individuals who had never smoked.
Genetic Deficiency of the Histamine H-Receptor Reduces Experimental Colorectal Carcinogenesis in Mice.
Schirmer Bastian,Rother Tamina,Bruesch Inga,Bleich Andre,Werlein Christopher,Jonigk Danny,Seifert Roland,Neumann Detlef
Colorectal cancer (CRC), a severe complication of inflammatory bowel diseases, is a common type of cancer and accounts for high mortality. CRC can be modeled in mice by application of the tumor promoter, azoxymethane (AOM), in combination with dextran sodium sulfate (DSS), which are able to induce colitis-like manifestations. Active colitis correlates with high mucosal concentrations of histamine, which, together with the histamine receptor subtype 4 (HR), provide a pro-inflammatory function in a mouse colitis model. Here, we analyzed whether HR is involved in the pathogenesis of AOM/DSS-induced CRC in mice. As compared to wild type (WT) mice, AOM/DSS-treated mice lacking HR expression (TM) demonstrate ameliorated signs of CRC, i.e., significantly reduced loss of body weight, stiffer stool consistency, and less severe perianal bleeding. Importantly, numbers and diameters of tumors and the degree of colonic inflammation are dramatically reduced in TM mice as compared to WT mice. This is concomitant with a reduced colonic inflammatory response involving expression of cyclooxygenase 2 and the production of C-X-C motif chemokine ligand 1 (CXCL1) and CXCL2. We conclude that HR is involved in the tumorigenesis of chemically-induced CRC in mice via cyclooxygenase 2 expression and, probably, CXCL1 and CXCL2 as effector molecules.
The impact of ranitidine on monocyte responses in the context of solid tumors.
Vila-Leahey Ava,Rogers Dakota,Marshall Jean S
Monocytes and myeloid derived suppressor cells (MDSC) have been implicated on the regulation of tumor growth. Histamine is also important for regulating MDSC responses. Oral administration of the H2 receptor antagonist ranitidine can inhibit breast tumor growth and metastasis. In the current study, we examined the impact of oral ranitidine treatment, at a clinically relevant dose, on multiple murine tumor models. The impact of ranitidine on monocyte responses and the role of CCR2 in ranitidine-induced tumor growth inhibition were also investigated. Oral ranitidine treatment did not reduce tumor growth in the B16-F10 melanoma, LLC1 lung cancer and EL4 thymoma models. However, it consistently reduced E0771 primary tumor growth and metastasis in the 4T1 model. Ranitidine had no impact on E0771 tumor growth in mice deficient in CCR2, where monocyte recruitment to tumors was limited. Analysis of splenic monocytes also revealed an elevated ratio of H2 versus H1 expression from tumor-bearing compared with naïve mice. More detailed examination of the role of ranitidine on monocyte development demonstrated a decrease in monocyte progenitor cells following ranitidine treatment. Taken together, these results reveal that H2 signaling may be a novel target to alter the monocyte population in breast tumor models, and that targeting H2 on monocytes via oral ranitidine treatment impacts effective tumor immunity. Ranitidine is widely used for control of gastrointestinal disorders. The potential role of ranitidine as an adjunct to immunotherapies for breast cancer and the potential impact of H2 antagonists on breast cancer outcomes should be considered.
Cimetidine suppresses lung tumor growth in mice through proapoptosis of myeloid-derived suppressor cells.
Zheng Yisheng,Xu Meng,Li Xiao,Jia Jinpeng,Fan Kexing,Lai Guoxiang
Cimetidine, a histamine type-2 receptor antagonist, is known to inhibit the growth of several tumors in human and animals, however the mechanism of action underlying this effect remains largely unknown. Here, in the mice model of 3LL lung tumor, cimetidine showed significant inhibition of tumor growth. However, an in vitro study demonstrated that cimetidine showed no effect on proliferation, survival, migration and invasion of 3LL cells. We found that cimetidine reduced CD11b(+)Gr-1(+) myeloid derived-suppressive cell (MDSC) accumulation in spleen, blood and tumor tissue of tumor-bearing mice. In vitro coculture assay showed that cimetidine reversed MDSC-mediated T-cell suppression, and improved IFN-γ production. Further investigation demonstrated that the NO production and arginase I expression of MDSCs were reduced, and MDSCs prone to apoptosis by cimetidine treatment. However, MDSC differentiation was not affect by cimetidine. Importantly, although histamine H2 receptor was expressed in MDSC surface, histamine could not reverse the proapoptosis of cimetidine. Moreover, famotidine also did not have this capacity. We found that cimetidine could induce Fas and FasL expression in MDSC surface, and sequentially regulate caspase-dependent apoptosis pathway. Thus, these findings revealed a novel mechanism for cimetidine to inhibit tumor via modulation of MDSC apoptosis.
Expression of histidine decarboxylase and synthesis of histamine by human small cell lung carcinoma.
Graff Lothar,Frungieri Mónica,Zanner Robert,Pohlinger Agnes,Prinz Christian,Gratzl Manfred
The American journal of pathology
We recently found that human small cell lung carcinomas (SCLCs) express, in addition to other neuroendocrine markers, vesicular monoamine transporters. Our present results indicate that SCLCs are histaminergic. We detected the biosynthetic enzyme histidine decarboxylase by immunohistochemistry in paraffin sections of 12 biopsies of SCLC tumors. This finding was supported by immunoblotting and reverse transcription-polymerase chain reaction experiments using established SCLC cell lines, frozen and paraffin-embedded SCLC tumors. Moreover, we found histamine to be synthesized, stored, and released by cultured SCLC cells. Our novel observations may be useful for developing new diagnostic tools for this frequent and highly malignant tumor.
The Role of Mast Cells in IgE-Independent Lung Diseases.
Komi Daniel Elieh Ali,Mortaz Esmaeil,Amani Saeede,Tiotiu Angelica,Folkerts Gert,Adcock Ian M
Clinical reviews in allergy & immunology
Mast cells (MCs) are granular cells of the innate immune system which develop from CD34/CD117 progenitors and play a role in orchestrating adaptive immune responses. They have a well-known role in allergic reactions following immunoglobulin (Ig)E-mediated activation of the cell-surface expressed IgE high-affinity receptor (FcεRI). MCs can also respond to various other stimuli due to the expression of a variety of receptors including toll-like receptors (TLRs), immunoglobulin (IgG) receptors (FcγR), complement receptors such as C5a (CD88) expressed by skin MCs, neuropeptides receptors including nerve growth factor receptor, (NGFR), cytokines receptors such as (IL)-1R and IL-3R, and chemokines receptors including CCR-1 and CCR-3. MCs release three groups of mediators upon degranulation differentiated according to their chemical composition, storage, and time to release. These include preformed mediators (mainly histamine, tryptase, and chymase), de novo synthesized mediators such as prostaglandin (PG)D2, leukotriene (LT)B4 and LTD4, and cytokines including IL-1β, IL-3, tumor necrosis factor (TNF)α, and transforming growth factor(TGF)-β. Emerging evidence indicates a role for IgE-independent MC activation in the late-stage asthmatic response as well as in non-allergic airway diseases including chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and lung cancer. MC infiltration/activation has been reported in some, but not all, studies of lung cancer. MC-derived TNF-α possesses tumor-suppressive activity while IL-1β supports tumor progression and metastasis. In IPF lungs, an increase in density of tryptase- and chymase-positive MCs (MCTC) and overexpression of TGF-β support the fibrosis progression. MC-derived chymase activates latent TGF-β that induces the differentiation of fibroblasts to matrix-producing myofibroblasts. In summary, increasing evidence highlights a critical role of MCs in non-allergic diseases that may indicate new approaches for therapy.
[A case of multiple lung metastases of colon cancer with long-term survival following 5'-DFUR and cimetidine therapy].
Fujiwara Shozo,Noguchi Tsuyoshi,Suehiro Syuji,Kikuchi Ryuichi,Noguchi Takuya,Uchida Yuzo
Gan to kagaku ryoho. Cancer & chemotherapy
A 77-year-old woman treated for diabetes mellitus was admitted to our hospital for further examination of abnormal findings on chest plain radiograph. Many nodular shadows in both lung fields were seen on chest X ray and chest CT scan. Colonoscopic examination revealed a type 2 tumor in the ascending colon. We diagnosed this case as ascending colon carcinoma with multiple lung metastases, and performed right hemicolectomy and D1 lymph node dissection. After surgery, the patient was administered 5'-DFUR 600 mg/body/day, cimetidine 800 mg/body/day orally. Though no remarkable reduction of tumors was recognized, the increase of tumor size was relatively slow. The patient remains alive 3 years after surgery.
The study of histamine H1- and H2-receptors in human lung cancer.
Kondratenko T Y,Zacharova I V,Katukov VYu ,Kuzina N V,Severin E S,Kornilova Z Ch,Perelman M I
Biochemistry and molecular biology international
Data on human lung histamine H1- and H2-receptors in cancer and chronic inflammatory processes are reported. It has been found that the number of histamine H1-receptors significantly increases both in cancer and chronic pneumonia and does not practically change in tuberculosis lung parenchyma. The binding parameters of histamine H2-receptors both in cancer and inflammatory processes were similar to those obtained for the normal tissue. The important role of parenchymal histamine H1-receptors in the neuromodulation of airways in human lung adenocarcinoma is discussed.
Dysfunctional inhibitory muscarinic receptors mediate enhanced histamine release in isolated human bronchi.
Wessler Ignaz,Hölper Björn,Kortsik Cornelius,Buhl Roland,Kilbinger Heinz,Kirkpatrick Charles James
In human airways mucosal mast cells are under the control of inhibitory muscarinic receptors. The described experiments tested, whether the inhibitory potency of two muscarinic receptor agonists (oxotremorine, acetylcholine) becomes impaired in advanced chronic obstructive pulmonary disease (COPD). Isolated human bronchi obtained from 26 patients with lung cancer were separated into two groups. Group 1 patients suffered from moderate COPD (mean FEV1 56%; range 34-71%; mean pack years of cigarette smoking 50, range 20-96; one non-smoker). Group 2 patients had no or only a mild form of COPD; mean FEV1 was 82% (62-97%) and the number of pack years 22 (6-45; 3 non-smoker). The calcium ionophore A23187 induced a maximal histamine release of 4100+/-870 pmol/g/5 min in group 1 bronchi, in contrast to only 1730+/-240 pmol/g/5 min in group 2 bronchi (p<0.02). Oxotremorine (1 nmol/L) reduced the stimulated histamine release by 81+/-5% in group 2 bronchi, but did not produce a significant effect in group 1 bronchi (11+/-14%). In conclusion, the present experiments show an enhanced histamine release in advanced COPD, which can be explained by a dysfunction of inhibitory muscarinic receptors.
RhoA and ROCK mediate histamine-induced vascular leakage and anaphylactic shock.
Mikelis Constantinos M,Simaan May,Ando Koji,Fukuhara Shigetomo,Sakurai Atsuko,Amornphimoltham Panomwat,Masedunskas Andrius,Weigert Roberto,Chavakis Triantafyllos,Adams Ralf H,Offermanns Stefan,Mochizuki Naoki,Zheng Yi,Gutkind J Silvio
Histamine-induced vascular leakage is an integral component of many highly prevalent human diseases, including allergies, asthma and anaphylaxis. Yet, how histamine induces the disruption of the endothelial barrier is not well defined. By using genetically modified animal models, pharmacologic inhibitors and a synthetic biology approach, here we show that the small GTPase RhoA mediates histamine-induced vascular leakage. Histamine causes the rapid formation of focal adherens junctions, disrupting the endothelial barrier by acting on H1R Gαq-coupled receptors, which is blunted in endothelial Gαq/11 KO mice. Interfering with RhoA and ROCK function abolishes endothelial permeability, while phospholipase Cβ plays a limited role. Moreover, endothelial-specific RhoA gene deletion prevents vascular leakage and passive cutaneous anaphylaxis in vivo, and ROCK inhibitors protect from lethal systemic anaphylaxis. This study supports a key role for the RhoA signalling circuitry in vascular permeability, thereby identifying novel pharmacological targets for many human diseases characterized by aberrant vascular leakage.
Phenotypic profiling of engineered mouse melanomas with manipulated histamine production identifies histamine H2 receptor and rho-C as histamine-regulated melanoma progression markers.
Pós Zoltán,Sáfrány Géza,Müller Kerstin,Tóth Sára,Falus András,Hegyesi Hargita
In the present study, the impact of acquired neoplastic L-histidine decarboxylase (HDC) expression, and its direct consequence, the release of histamine in the tumor environment, was assessed on melanoma tumor progression. B16-F10 mouse melanoma cells were manipulated via stable transfection, and nine novel transgenic variants were generated in triplicates, constitutively expressing the full-length sense mouse HDC mRNA, a mock control, and an antisense HDC RNA segment, respectively. Establishing both primary skin tumors and lung metastases in C57BL/6 mice, the nine variants with different histamine-releasing capacities were subjected to a comprehensive comparative progression profiling in vivo. Our analyses showed trends of markedly accelerated tumor growth (P < 0.001), and moderately increased metastatic colony-forming potential (P = 0.010) along with rising levels of local histamine production. Using RNase protection assay for screening of the melanoma progression profile, and Western blotting for subsequent result validation, we looked for molecular progression markers affected by melanoma histamine secretion. Investigation of 21 functionally clustered markers associated with tumor proliferation, angiogenesis, invasivity, metastasis formation, local or systemic immunomodulation, and histamine signaling revealed positive correlations between histamine production, tumor histamine H2 receptor and rho-C expression (P < 0.001, P = 0.002, respectively). These observations confirm the involvement of histamine in the molecular machinery of melanoma progression.
The role of histamine in opening blood-tumor barrier.
Wang Zeng,Cai Xin-Jun,Qin Jing,Xie Fa-Jun,Han Na,Lu Hong-Yang
Blood-tumor barrier (BTB) reduce the permeability for drugs into tumor tissues. We found that histamine might serve as an essential regulator of BTB function. Further, we aim to determine the role of H2 receptor expression in BTB permeability, and elucidate the underlying mechanisms thereof. Transmission electron microscopy showed that histamine disrupted the integrity of tight junctions (TJ) and increased the number of pinosomes in the cytoplasm. Horseradish peroxidase (HRP) and trans-endothelial resistance detection (TEER) assays revealed that histamine could open BTB and this action was inhibited by cimetidine. Western blot and immunofluorescence assays showed that histamine decreased the expression of tight junction proteins zonula occluden-1(ZO-1), occludin, and claudin-5. Further, quantitative RT-PCR assay showed that the expression of H2 receptor could represent and predicted histamine-induced BTB permeability. In conclusion, histamine opened BTB by down-regulating the TJ-associated proteins. The levels of H2 receptor expression was correlated with the histamine-induced BTB permeability.
Immunomodulatory role of histamine H4 receptor in breast cancer.
Sterle Helena A,Nicoud Melisa B,Massari Noelia A,Táquez Delgado Mónica A,Herrero Ducloux María V,Cremaschi Graciela A,Medina Vanina A
British journal of cancer
BACKGROUND:Although the role of histamine H4 receptor (H4R) in immune cells is being extensively investigated, its immunomodulatory function in cancer is completely unknown. This study aimed to investigate the role of H4R in antitumour immunity in a model of triple-negative breast cancer. METHODS:We evaluated growth parameters, histological characteristics and the composition of tumour, splenic and tumour draining lymph node (TDLN) immune subsets, in a syngeneic model, developed orthotopically with 4T1 cells in H4R knockout (H4R-KO) and wild-type mice. RESULTS:Mice lacking H4R show reduced tumour size and weight, decreased number of lung metastases and percentage of CD4 tumour-infiltrating T cells, while exhibiting increased infiltration of NK cells and CD19 lymphocytes. Likewise, TDLN of H4R-KO mice show decreased CD4 T cells and T regulatory cells (CD4CD25FoxP3), and increased percentages of NK cells. Finally, H4R-deficient mice show decreased Tregs in spleens and non-draining lymph nodes, and a negative correlation between tumour weight and the percentages of CD4, CD19 and NK splenic cells, suggesting that H4R also regulates antitumour immunity at a systemic level. CONCLUSIONS:This is the first report that demonstrates the participation of H4R in antitumour immunity, suggesting that H4R could be a target for cancer treatment.
Histamine receptors and cancer pharmacology: an update.
Massari Noelia A,Nicoud Melisa B,Medina Vanina A
British journal of pharmacology
In the present review, we will discuss the recent advances in the understanding of the role of histamine and histamine receptors in cancer biology. The controversial role of the histaminergic system in different neoplasias including gastric, colorectal, oesophageal, oral, pancreatic, liver, lung, skin, blood and breast cancers will be reviewed. The expression of histamine receptor subtypes, with special emphasis on the histamine H receptor, in different cell lines and human tumours, the signal transduction pathways and the associated biological responses as well as the in vivo treatment of experimental tumours with pharmacological ligands will be described. The presented evidence demonstrates that histamine regulates cancer-associated biological processes during cancer development in multiple cell types, including neoplastic cells and cells in the tumour micro-environment. The outcome will depend on tumour cell type, the level of expression of histamine receptors, signal transduction associated with these receptors, tumour micro-environment and histamine metabolism, reinforcing the complexity of cancer disease. Findings show the pivotal role of H receptors in the development and progression of many types of cancers, and considering its immunomodulatory properties, the H receptor appears to be the most promising molecular therapeutic target for cancer treatment within the histamine receptor family. Furthermore, the H receptor is differentially expressed in tumours compared with normal tissues, and in most cancer types in which data are available, H receptor expression is associated with clinicopathological characteristics, suggesting that H receptors might represent a novel cancer biomarker. LINKED ARTICLES: This article is part of a themed section on New Uses for 21st Century. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.3/issuetoc.
Pathophysiological Role of Histamine H4 Receptor in Cancer: Therapeutic Implications.
Nicoud Melisa B,Formoso Karina,Medina Vanina A
Frontiers in pharmacology
Cancer is a leading cause of death in both developed and developing countries. Although advances in cancer research lead to improved anti-neoplastic therapies, they continue to have unfavorable outcomes, including poor response and severe toxicity. Thus, the challenge for the new therapeutic approaches is to increase anti-tumor efficacy by targeting different molecules encompassed in the tumor and its microenvironment, as well as their specific interactions. The histamine H4 receptor (H4R) is the last discovered histamine receptor subtype and it modulates important immune functions in innate and in adaptive immune responses. Several ligands have been developed and some of them are being used in clinical trials for immune disorders with promising results. When searched in The Cancer Genome Atlas (TCGA) database, human H4R gene was found to be expressed in bladder cancer, kidney cancer, breast cancer, gastrointestinal cancers, lung cancer, endometrial cancer, and skin cancer. In the present work, we aimed to briefly summarize current knowledge in H4R's pharmacology and in the clinical use of H4R ligands before focusing on recent data reporting the expression of H4R and its pathophysiological role in cancer, representing a potential molecular target for cancer therapeutics. H4R gene and protein expression in different types of cancers compared with normal tissue as well as its relationship with patient prognosis in terms of survival will be described.
Repurposing Cationic Amphiphilic Antihistamines for Cancer Treatment.
Ellegaard Anne-Marie,Dehlendorff Christian,Vind Anna C,Anand Atul,Cederkvist Luise,Petersen Nikolaj H T,Nylandsted Jesper,Stenvang Jan,Mellemgaard Anders,Østerlind Kell,Friis Søren,Jäättelä Marja
Non-small cell lung cancer (NSCLC) is one of the deadliest cancers worldwide. In search for new NSCLC treatment options, we screened a cationic amphiphilic drug (CAD) library for cytotoxicity against NSCLC cells and identified several CAD antihistamines as inducers of lysosomal cell death. We then performed a cohort study on the effect of CAD antihistamine use on mortality of patients diagnosed with non-localized cancer in Denmark between 1995 and 2011. The use of the most commonly prescribed CAD antihistamine, loratadine, was associated with significantly reduced all-cause mortality among patients with non-localized NSCLC or any non-localized cancer when compared with use of non-CAD antihistamines and adjusted for potential confounders. Of the less frequently described CAD antihistamines, astemizole showed a similar significant association with reduced mortality as loratadine among patients with any non-localized cancer, and ebastine use showed a similar tendency. The association between CAD antihistamine use and reduced mortality was stronger among patients with records of concurrent chemotherapy than among those without such records. In line with this, sub-micromolar concentrations of loratadine, astemizole and ebastine sensitized NSCLC cells to chemotherapy and reverted multidrug resistance in NSCLC, breast and prostate cancer cells. Thus, CAD antihistamines may improve the efficacy of cancer chemotherapy.
Skin reactivity to histamine and expression of histamine receptors mRNA in lymphocytes of healthy subjects and non-small-cell lung cancer patients before and after surgery.
Zak-Nejmark Teresa,Jankowska Renata,Passowicz-Muszynska Ewa,Malolepszy Jozef,Marciniak Marek,Jonkisz Anna,Kraus-Filarska Maria
Lung cancer (Amsterdam, Netherlands)
Histamine modulates an immunological response through stimulation of appropriate receptor--H1R proinflammatory or H2R suppressive. The participation of histamine in regulation of an immunological response in the course of neoplastic disease is determined by the expression of particular receptor. The aim of our work was the investigation of the expression of mRNA of two types of histamine receptors in peripheral blood lymphocytes and the evaluation of skin-prick test with histamine in lung cancer patients before and after surgery. The investigation was performed on 15 patients qualified to surgery before and 7-10 days after treatment and on 12 healthy subjects. Reverse transcriptase polymerase chain reaction (RT-PCR) with primers labeled with fluorescent dyes was performed. Intensity of fluorescence was expressed as relative fluorescence units (RFU). The data were analysed using ABI Prism 310 GeneScan collection software Version 3.1. Skin-prick test with histamine was evaluated after 10 min by measuring the diameter of the weal. The expression of H1R and H2R mRNA in healthy subjects was not significantly different in contrast to the lung cancer patients in which a significant prevalence of H2R mRNA expression was observed before surgery and only slightly decreased after (P < 0.001). Skin-prick test--negative in one patient before surgery, after treatment was positive in all patients and the diameter of histamine weal was significantly increased (P < 0.001). One may assume that the prevalence of the expression of H2R mRNA in patients reflects the status of immunosuppression caused by cancer. Since histamine exerts its suppressive activity trough H2R it seems reasonably to include the antagonists of this receptor to the cancer therapy which may restore a relative balance between accessibility of both types of histamine receptors.
Gastric Acid suppression is associated with decreased erlotinib efficacy in non-small-cell lung cancer.
Chu Michael P,Ghosh Sunita,Chambers Carole R,Basappa Naveen,Butts Charles A,Chu Quincy,Fenton David,Joy Anil A,Sangha Randeep,Smylie Michael,Sawyer Michael B
Clinical lung cancer
BACKGROUND:Erlotinib is a key therapy for advanced NSCLC. Concurrent AS therapy with TKIs might reduce TKI plasma levels. Because of gastroesophageal reflux disease prevalence, this retrospective analysis was undertaken to determine if coadministering erlotinib with AS therapy affected NSCLC outcomes. PATIENTS AND METHODS:Records of advanced NSCLC patients who received erlotinib from 2007 to 2012 at a large, centralized, cancer institution were retrospectively reviewed. Pertinent demographic data were collected and concomitant AS treatment was defined as AS prescription dates overlapping with ≥ 20% of erlotinib treatment duration. Records of patients who received erlotinib for ≥ 1 week were analyzed for progression-free survival (PFS) and overall survival (OS). RESULTS:Stage IIIB/IV NSCLC patients (n = 544) were identified and 507 had adequate data for review. The median age was 64 years and 272 were female. Adenocarcinoma (n = 318; 64%) and squamous (n = 106; 21%) were predominant subtypes; 124 patients received concomitant AS therapy. In this unselected population, median PFS and OS in AS versus no AS groups were 1.4 versus 2.3 months (P < .001) and 12.9 versus 16.8 months (P = .003), respectively. Factoring sex, subtype, and performance status in multivariate Cox proportional hazards ratios for PFS and OS between AS and no AS groups were 1.83 (95% confidence interval [CI], 1.48-2.25) and 1.37 (95% CI, 1.11-1.69), respectively. CONCLUSION:This large population-based study suggests erlotinib efficacy might be linked with gastric pH and OS could be adversely affected. To our knowledge, this is the first study demonstrating a possible negative clinical effect of coadministration of erlotinib with AS therapy. Further prospective investigation is warranted.
Histamine regulates cyclooxygenase 2 gene activation through Orai1-mediated NFκB activation in lung cancer cells.
Huang Wan-Chen,Chai Chee-Yin,Chen Wei-Chiao,Hou Ming-Feng,Wang Yu-Shiuan,Chiu Yi-Ching,Lu Shiang-Ru,Chang Wen-Chang,Juo Suh-Hang Hank,Wang Jaw-Yuan,Chang Wei-Chiao
Histamine, an important chemical mediator, has been shown to regulate inflammation and allergic responses. Stimulation of histamine receptors results in a significant increase in cytoplasmic Ca(2+), which could be mediated by inositol trisphosphate (IP(3))-dependent store-operated Ca(2+) channels (SOC). However, the link between histamine-mediated signaling and activation of inflammatory genes such as cyclooxygenase 2 (COX-2) is still unknown. Our study indicated that the COX-2 protein was highly expressed in human lung cancer cells. Following stimulation with 10 μM of histamine, both store-operated Ca(2+) entry (SOCE) and COX-2 gene expression were evoked. Histamine-mediated COX-2 activation can be prevented by 2-APB and SKF-96365, SOC channel inhibitors. In addition, deletion analysis of the COX-2 promoter suggested that the region between -80 bp and -250 bp, which contains NFκB binding sites, is the key element for histamine-mediated signaling. Knocking down ORAI1, one of the essential molecules of store-operated calcium channels, attenuated histamine-mediated COX-2 expression and NFκB activation. These results indicated that ORAI1-mediated NFκB activation was an important signaling pathway, responsible for transmitting histamine signals that trigger inflammatory reactions.
Clinical Impact of Gastric Acid-Suppressing Medication Use on the Efficacy of Erlotinib and Gefitinib in Patients With Advanced Non-Small-Cell Lung Cancer Harboring EGFR Mutations.
Zenke Yoshitaka,Yoh Kiyotaka,Matsumoto Shingo,Umemura Shigeki,Niho Seiji,Ohmatsu Hironobu,Goto Koichi,Ohe Yuichiro
Clinical lung cancer
BACKGROUND:Gastric acid-suppressing medications (AS), namely, proton pump inhibitors and histamine-2 receptor antagonists, increase gastric pH, which may reduce the absorption of the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors-erlotinib and gefitinib. PATIENTS AND METHODS:From 2008 to 2011, 130 consecutive patients with advanced non-small-cell lung cancer (NSCLC) harboring EGFR mutations were treated with either erlotinib or gefitinib at our institution. The clinical characteristics of the patients were reviewed, and the efficacy and toxicity of erlotinib and gefitinib were compared for patients receiving and not receiving AS. RESULTS:Among the 130 patients, 47 received AS (AS users group), while the remaining 83 patients did not (AS non-users group). The overall response rate (ORR) and median progression-free survival (PFS) in the subject population was 60% and 10 months, respectively. In the AS users and non-users groups, the ORR was 64% and 63% (P = .92), while the median PFS was 8.7 and 10.7 months (P = .13), respectively. No significant difference in either ORR or PFS was observed between the 2 groups. With regard to the toxicity, the frequencies of rash (83% vs. 86%; P = .60) and diarrhea (34% vs. 29%; P = .55) were similar for both groups. A multivariate analysis identified that AS use was not a significant factor for either PFS or OS. CONCLUSION:Concurrent use of AS did not affect the efficacy or toxicity of erlotinib and gefitinib in patients with advanced NSCLC harboring EGFR mutations.
Histamine-2 receptor antagonists and risk of lung cancer in diabetic patients – an exploratory analysis.
Hsu Chia-Lin,Chang Chia-Hsuin,Lin Jou-Wei,Wu Li-Chiu,Chuang Lee-Ming,Lai Mei-Shu
Pharmacoepidemiology and drug safety
PURPOSE:Histamine-2 receptor blockers (H2RBs) might have anti-tumorogenic effect, but the clinical effect on lung cancer occurrence was unclear. METHODS:A total of 640,173 type 2 diabetic patients were identified from the Taiwan National Health Insurance claims database in 2000. Patients were followed from cohort entry to the earliest of cancer diagnosis, death, disenrollment from the national health insurance, or 31 December 2007. For each participant, H2RB use during the follow-up period was ascertained from the outpatient pharmacy prescription database. Patients with incident squamous cell carcinoma (SCC) and adenocarcinoma were included as cases and up to four age- and sex-matched controls were selected by risk-set sampling. Conditional logistic regression models were applied to estimate the association between H2RBs and lung cancer incidence. RESULTS:A total of 1182 incident SCC and 2345 adenocarcinoma cases were identified, and 13,108 matched controls were selected. An increased risk was observed for H2RBs use <1 year with adjusted OR of 1.33 (95% confidence interval (CI): 1.22–1.44). After excluding all exposures occurring in the year before lung cancer diagnosis, H2RBs use with cumulative dosage ≥ 360 “defined daily doses” was associated with a significantly decreased risk of lung cancer (OR: 0.60; 95% CI: 0.38–0.96). When we stratified on types of lung cancer, the protective association of higher cumulative use of H2RBs seemed more evident for lung adenocarcinoma, with an adjusted OR of 0.49 (95% CI: 0.26–0.90). CONCLUSIONS:Higher cumulative use of H2RBs might be associated with a reduced risk for non-small cell lung cancer in diabetic patients.
Effects of Histamine 2-receptor Antagonists and Proton Pump Inhibitors on the Pharmacokinetics of Gefitinib in Patients With Non-small-cell Lung Cancer.
Yokota Hayato,Sato Kazuhiro,Okuda Yuji,Kobayashi Hiroyuki,Takeda Masahide,Asano Mariko,Ito Hiroshi,Miura Masatomo
Clinical lung cancer
INTRODUCTION:In this study, we investigated the degree of drug interactions between gefitinib and gastric acid suppressants (ie, histamine 2-receptor antagonists [H2RAs] or proton pump inhibitors [PPIs]) with a clinical standard dose in Japanese patients with non-small-cell lung cancer. METHODS:Retrospectively, 47 patients were divided into 3 groups: gefitinib therapy with a PPI (15 patients) or an H2RA (8 patients) or gefitinib therapy alone (24 patients). On day 15 after beginning gefitinib therapy (administration at 08:00) with or without H2RA (administration twice daily at 08:00 and 18:30) or PPI (administration once daily at 08:00 or 18:30), whole blood samples were collected just prior to and at 1, 2, 4, 6, 8, 12, and 24 hours after administration. RESULTS:The total area under the observed plasma concentration-time curve (AUC) and the maximum and trough plasma concentrations of gefitinib with the PPI were significantly lower than those without the PPI. The AUC of gefitinib with PPI administration in either the morning or evening were significantly lower than those without PPI administration (P = .015 and .049, respectively); however, there were no significant differences in gefitinib AUC between patients taking PPI in the morning and evening. No significant differences were observed in gefitinib exposure among the 3 CYP2C19 genotypes. The AUC of gefitinib with H2RA tended to be lower than that without H2RA. CONCLUSION:If the plasma concentrations of gefitinib cannot be monitored, the combination of gefitinib and PPI should be avoided, and an H2RA should also be used carefully.
Activation of histamine H4 receptors decreases epithelial-to-mesenchymal transition progress by inhibiting transforming growth factor-β1 signalling pathway in non-small cell lung cancer.
Cai Wen-Ke,Hu Jing,Li Teng,Meng Jing-Ru,Ma Xue,Yin Sun-Jun,Zhao Can-Hu,He Gong-Hao,Xu Gui-Li
European journal of cancer (Oxford, England : 1990)
Previous investigations found that epithelial-to-mesenchymal transition (EMT) was an important character of non-small cell lung cancer (NSCLC) and it was also suggested that histamine H4 receptors may have a role in preventing EMT progress in certain kind of tumours. However, the effect of H4 receptor activation on EMT progress of NSCLC and its potential mechanisms remain unclear. Therefore, we performed both in vitro and in vivo experiments to explore the effects of specific H4 receptor agonist 4-methylhistamine and antagonist JNJ7777120 on EMT progress. We showed the expression of H4 receptors in NSCLC and found that 4-methylhistamine increased the expression of the epithelial marker E-cadherin and decreased the expression of Vimentin, the mesenchymal marker, in both NSCLC cell lines and xenograft NSCLC tumours. Pretreatment with JNJ7777120 or H4 receptor gene silencing decreased while overexpression of H4 receptors facilitated this effect of 4-methylhistamine. Furthermore, we showed that down-regulation of cyclic adenosine monophosphate (cAMP) was the secondary signalling after H4 receptor activation, which in turn resulted in inactivation of transforming growth factor-β1 (TGF-β1) pathway and down-regulation of several important EMT inducing factors such as ZEB1, Snail and Slug. In conclusion, these findings revealed the anti-EMT effect of histamine H4 receptor activation in NSCLC, which provide novel insight into the development mechanism of NSCLC; and H4 receptors may be a new therapeutic target for NSCLC treatment.
Mast cells and histamine enhance the proliferation of non-small cell lung cancer cells.
Stoyanov Evgeniy,Uddin Mohib,Mankuta David,Dubinett Steven M,Levi-Schaffer Francesca
Lung cancer (Amsterdam, Netherlands)
Non-small cell lung cancer (NSCLC) is the most common form of lung cancer with an extremely low survival rate. It is characterized by a chronic inflammatory process with intense mast cell infiltrate that is associated with reduced survival. The aim of this study was to test the hypothesis that mast cells have an enhancing effect on NSCLC proliferation. To assess the tumor-promoting potential of mast cells, we used the human alveolar basal adenocarcinoma (A549) and the mouse Lewis lung carcinoma (LLC) cell lines, umbilical cord blood-derived mast cells (CBMC) and the mast cell-deficient mouse Sash model. The proliferation rate of A549/LLC cells was markedly increased by mast cells and histamine. Histamine proliferating activity was mediated via H(1), H(2) and H(4) receptors and caused ERK phosphorylation. LLC induced in Sash mice or in wild-type mice treated with the mast cell stabilizer nedocromil sodium displayed an accelerated growth (number of metastic colonies in the lungs, total lung area and lung/total mice weight ratio). In summary, we have shown a significant effect of mast cells and histamine in enhancing NSCLC/LLCX growth in vitro, while in a mouse LLC model in vivo we have found that mast cells are important negative regulators of cancer development. Therefore our results would indicate a pro-tumorogenic effect of the mast cells in vitro on established lung tumor cell lines, and anti-tumorogenic effect in mice at lung cancer induction. In conclusion, mast cell/anti-histamine targeted therapies should carefully consider this dual effect.
Oxygen Sensing by T Cells Establishes an Immunologically Tolerant Metastatic Niche.
Clever David,Roychoudhuri Rahul,Constantinides Michael G,Askenase Michael H,Sukumar Madhusudhanan,Klebanoff Christopher A,Eil Robert L,Hickman Heather D,Yu Zhiya,Pan Jenny H,Palmer Douglas C,Phan Anthony T,Goulding John,Gattinoni Luca,Goldrath Ananda W,Belkaid Yasmine,Restifo Nicholas P
Cancer cells must evade immune responses at distant sites to establish metastases. The lung is a frequent site for metastasis. We hypothesized that lung-specific immunoregulatory mechanisms create an immunologically permissive environment for tumor colonization. We found that T-cell-intrinsic expression of the oxygen-sensing prolyl-hydroxylase (PHD) proteins is required to maintain local tolerance against innocuous antigens in the lung but powerfully licenses colonization by circulating tumor cells. PHD proteins limit pulmonary type helper (Th)-1 responses, promote CD4(+)-regulatory T (Treg) cell induction, and restrain CD8(+) T cell effector function. Tumor colonization is accompanied by PHD-protein-dependent induction of pulmonary Treg cells and suppression of IFN-γ-dependent tumor clearance. T-cell-intrinsic deletion or pharmacological inhibition of PHD proteins limits tumor colonization of the lung and improves the efficacy of adoptive cell transfer immunotherapy. Collectively, PHD proteins function in T cells to coordinate distinct immunoregulatory programs within the lung that are permissive to cancer metastasis. PAPERCLIP.
Tumor-infiltrating Foxp3+ regulatory T cells are correlated with cyclooxygenase-2 expression and are associated with recurrence in resected non-small cell lung cancer.
Shimizu Katsuhiko,Nakata Masao,Hirami Yuji,Yukawa Takuro,Maeda Ai,Tanemoto Kazuo
Journal of thoracic oncology : official publication of the International Association for the Study of Lung Cancer
BACKGROUND:Cyclooxygenase-2 (COX-2) is constitutively overexpressed in a variety of epithelial malignancies and is usually associated with a poor prognosis. COX-2-derived prostaglandin E2 transforms CD4+CD25+ T regulatory (Treg) cells (Tregs), and Tregs are thought to moderate the antitumor immune response. Herein, we investigated the prognostic value of tumor-infiltrating Treg cells and their correlation with COX-2 expression in resected non-small cell lung cancer (NSCLC). MATERIAL AND METHODS:Intratumoral COX-2 and Treg expression were retrospectively assessed using immunohistochemistry in paraffin-embedded samples from 100 patients who had undergone complete resections for NSCLC. The expressions of COX-2 and Foxp3, which was most specific Treg cell marker, were compared with the clinicopathological variables, and the correlation between Foxp3+ Tregs and COX-2 expression was analyzed. RESULTS:The recurrence-free survival (RFS) of patients with elevated COX-2 expression was significantly worse than that of patients without COX-2 expression. Tumor-infiltrating Foxp3-positive lymphocytes were positively correlated with COX-2 expression. The median count for Foxp3-positive lymphocytes was 3 (minimum-maximum, 0-24) in 10 high-power fields. The RFS of patients with tumors containing >or=3 Foxp3-positive cells (Foxp3 expression group) was significantly worse than that of patients with tumors containing <3 Foxp3-positive cells. In a multivariate analysis, only nodal status was an independent predictor of a significantly shorter RFS. However, in node-negative NSCLC, Foxp3 expression was an independent predictor of a significantly shorter RFS. CONCLUSIONS:Tumor-infiltrating Foxp3+ Tregs were positively correlated with intratumoral COX-2 expression and were associated with a worse RFS, especially among patients with node-negative NSCLC.
Increase in activated Treg in TIL in lung cancer and in vitro depletion of Treg by ADCC using an antihuman CCR4 mAb (KM2760).
Kurose Koji,Ohue Yoshihiro,Sato Eiichi,Yamauchi Akira,Eikawa Shingo,Isobe Midori,Nishio Yumi,Uenaka Akiko,Oka Mikio,Nakayama Eiichi
Journal of thoracic oncology : official publication of the International Association for the Study of Lung Cancer
INTRODUCTION:Tregs infiltrate tumors and inhibit immune responses against them. METHODS:We investigated subpopulations of Foxp3 CD4 T cells previously defined by Miyara et al. (Immunity 30, 899-911, 2009) in peripheral blood mononuclear cells (PBMCs) and tumor infiltrating lymphocytes (TILs) in lung cancer. We also showed that Tregs in healthy donors that express CCR4 could be efficiently eliminated in vitro by cotreatment with antihuman (h) CCR4 mAb (KM2760) and NK cells. RESULTS:In lung cancer, the number of activated/effector Tregs and non-Tregs, but not resting/naive Tregs, was increased in TILs compared with the number of those cells in PBMCs. The non-Treg population contained Th2 and Th17. CCR4 expression on activated/effector Tregs and non-Tregs in TILs was down-regulated compared with that on those cells in PBMCs. Chemokinetic migration of CD25 CD4 T cells containing the Treg population sorted from the PBMCs of healthy donors to CCL22/MDC was abrogated by pretreatment with anti-hCCR4 mAb (KM2760). The inhibitory activity of CD25 CD127 CD4 Tregs on the proliferative response of CD4 and CD8 T cells stimulated with anti-CD3/CD28 coated beads was abrogated by adding an anti-hCCR4 mAb (KM2760) and CD56 NK cells to the culture. CONCLUSIONS:The findings suggested the CCR4 on activated/effector Tregs and non-Tregs was functionally involved in the chemokinetic migration and accumulation of those cells to the tumor site. In vitro findings of efficient elimination of Tregs may give the basis for implementation of a clinical trial to investigate Treg depletion by administration of an anti-hCCR4 mAb to solid cancer patients.