Impaired STAT Phosphorylation in T Cells from Melanoma Patients in Response to IL-2: Association with Clinical Stage

• Published in: Clinical cancer research Vol. 15; no. 12; pp. 4085 - 4094
• Main Authors: Mortarini, Roberta, Vegetti, Claudia, Molla, Alessandra, Arienti, Flavio, Ravagnani, Fernando, Maurichi, Andrea, Patuzzo, Roberto, Santinami, Mario, Anichini, Andrea
• Format: Journal Article
• Language: English
• Published: United States American Association for Cancer Research 15.06.2009
• Subjects: CD3 Complex - immunology; CD3 Complex - metabolism; Cell Proliferation - drug effects; Humans; IL-2; Interleukin-15 - pharmacology; Interleukin-2 - pharmacology; Janus Kinase 3 - immunology; Janus Kinase 3 - metabolism; Killer Cells, Natural - drug effects; Killer Cells, Natural - immunology; Killer Cells, Natural - metabolism; Melanoma; Melanoma - immunology; Melanoma - pathology; Neoplasm Staging; phospho-specific flow cytometry; Phosphorylation - drug effects; Receptors, Cytokine - immunology; Receptors, Cytokine - metabolism; Skin Neoplasms - immunology; Skin Neoplasms - pathology; STAT proteins; STAT1 Transcription Factor - metabolism; STAT5 Transcription Factor - metabolism; T cells; T-Lymphocytes - drug effects; T-Lymphocytes - metabolism
• ISSN: 1078-0432; 1557-3265
• DOI: 10.1158/1078-0432.CCR-08-3323

Purpose: To assess the extent of signal transducer and activator of transcription (STAT) activation in response to interleukin 2 (IL-2) in melanoma patients' T cells, along with clinical stage of tumor progression. Experimental Design: T lymphocytes from peripheral blood of healthy donors and of American Joint Committee on Cancer stage I to IV melanoma patients, as well as from metastatic lymph nodes of patients, were evaluated for responsiveness to IL-2. CFSE assays and single-cell phospho-STAT–specific flow cytometry screening were used. Results . T cells from advanced melanoma patients, in comparison with healthy donors, showed reduced proliferation to IL-2 and IL-15, but not to anti-CD3 monoclonal antibody. Impaired response occurred in CCR7 + and CCR7 − T-cell subsets, but not in CD3 − CD8 + natural killer (NK) cells, and was not explained by induction of apoptosis, increased cytokine consumption, or altered IL-2R subunit expression in patients' T lymphocytes. By phospho-specific flow cytometry, defective STAT1 and STAT5 activation in response to IL-2 was found mainly in T lymphocytes from peripheral blood and/or tumor site of American Joint Committee on Cancer stage III and IV patients, compared with stage I and II patients and to donors, and in melanoma antigen-specific T cells isolated from metastatic lymph nodes. At tumor site, impaired STAT activation in T cells did not correlate with frequency of CD4 + CD25 + Foxp3 + T cells. Serum from advanced melanoma patients inhibited IL-2–dependent STAT activation in donors' T cells and a neutralizing monoclonal antibody to transforming growth factor β1 counteracted such inhibition. Conclusions: These results provide evidence for development of impaired STAT signaling in response to IL-2, along with clinical evolution of the disease, in melanoma patients' T cells.