Nilotinib hampers the proliferation and function of CD8+ T lymphocytes through inhibition of T cell receptor signaling

Third Department of Internal Medicine, University of Ulm, Ulm, Germany.
Journal of Cellular and Molecular Medicine (Impact Factor: 4.01). 02/2008; 12(5B):2107-18. DOI: 10.1111/j.1582-4934.2008.00234.x
Source: PubMed


The novel selective BCR-ABL Breakpoint cluster region--Abelson murine leukemia viral oncogene homolog 1 (BCR-AML) inhibitor nilotinib (AMN107) is a tyrosine kinase inhibitor that is more potent against leukaemia cells in vitro than imatinib. As nilotinib might be used in the context of allogeneic stem cell transplantation where CD8+ T lymphocytes play a pivotal role in the graft-versus-leukaemia (GVL) effect, we investigated effects of nilotinib on this lymphocyte subpopulation. Nilotinib inhibits phytohemagglutinin (PHA)-induced proliferation of CD8+T lymphocytes in vitro at therapeutically relevant concentrations (0.5-4 microM). The inhibition of CD8+ T lymphocytes specific for leukaemia or viral antigens through nilotinib was associated with a reduced expansion of antigen peptide specific CD8+ T lymphocytes and with a decreased release of interferon-gamma and granzyme B by these cells as analysed by flow cytometry and enzyme-linked immunospot (ELISPOT) assays. The inhibitory effect caused by nilotinib was two times stronger than by imatinib. These effects were mediated through the inhibition of the phosphorylation of ZAP-70, Lck and ERK 1/2 and the NF-kappaB signalling transduction pathway. Taken together, we observed a strong suppressive impact of nilotinib on the CD8+ T lymphocyte function which should be considered carefully in the framework of allogeneic stem cell transplantation or other T cell based immunotherapies.

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Available from: Michael Schmitt, Nov 18, 2014
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    • "Nevertheless, this population gradually vanished in the peripheral blood of patients after they received chemotherapy. Potentially downregulating effects of chemotherapy on T cells have been reported previously [6, 33, 34]. Interestingly the frequency of RHAMM-specific T cells increased in the bone marrow which might indicate a trafficking of these cells into the bone marrow [35]. "
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    ABSTRACT: Leukemic blasts overexpress immunogenic antigens, so-called leukemia-associated antigens like the receptor for hyaluronan acid-mediated motility (RHAMM). Persistent RHAMM expression and decreasing CD8 + T-cell responses to RHAMM in the framework of allogeneic stem cell transplantation or chemotherapy alone might indicate the immune escape of leukemia cells. In the present study, we analyzed the expression of RHAMM in 48 patients suffering from acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Furthermore, we correlated transcripts with the clinical course of the disease before and after treatment. Real-time quantitative reverse transcriptase polymerase chain reaction was performed from RNA of peripheral blood mononuclear cells. T cell responses against RHAMM were assessed by tetramer staining (flow cytometry) and enzyme-linked immunospot (ELISPOT) assays. Results were correlated with the clinical outcome of patients. The results of the present study showed that almost 60% of the patients were RHAMM positive; specific T-cells recognizing RHAMM could be detected, but they were nonfunctional in terms of interferon gamma or granzyme B release as demonstrated by ELISPOT assays. Immunotherapies like peptide vaccination or adoptive transfer of RHAMM-specific T cells might improve the immune response and the outcome of AML/MDS patients.
    Full-text · Article · Jun 2012 · Clinical and Developmental Immunology
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    • "Nilotinib only showed significant inhibitory effect on CD4+CD25+ T cells or CD4+CD25- T cells at a concentration higher than 10 μM. However, Chen et al showed that nilotinib inhibits phytohemagglutinin (PHA)-induced proliferation of CD8+ T cells in vitro at therapeutically relevant concentrations (0.5-4 μM) [16]. Similar results were also shown by Blake et al. [30]. "
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    ABSTRACT: Nilotinib is a tyrosine kinase inhibitor with high target specificity. Here, we characterized the effects of nilotinib for the first time on CD4+CD25+ regulatory T cells (Tregs) which regulate anti-tumor/leukemia immune responses. Carboxyfluorescein diacetate succinimidyl ester (CFSE) and 5-bromo-2-deoxy -uridine (BrdU) were used to assess the proliferation and cell cycle distribution of Tregs. The expression of the transcription factor forkhead box P3 (FoxP3) and the glucocorticoid-induced tumor necrosis factor receptor (GITR) were measured by flow cytometry. Western blotting analysis was used to detect the effects of nilotinib on the signal transduction cascade of T-cell receptor (TCR) in Tregs. Nilotinib inhibited the proliferation and suppressive capacity of Tregs in a dose-dependent manner. However, the production of cytokines secreted by Tregs and CD4+CD25- T cells was only inhibited at high concentrations of nilotinib exceeding the mean therapeutic serum concentrations of the drug in patients. Only high doses of nilotinib arrested both Tregs and CD4+CD25- T cells in the G0/G1 phase and down-regulated the expression of FoxP3 and GITR. In western blotting analysis, nilotinib did not show significant inhibitory effects on TCR signaling events in Tregs and CD4+CD25- T cells. These findings indicate that nilotinib does not hamper the function of Tregs at clinical relevant doses, while long-term administration of nilotinib still needs to be investigated.
    Full-text · Article · Jan 2010 · Molecular Cancer

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