RESUMO
In cutaneous T cell lymphomas (CTCL), miR-21 is aberrantly expressed in skin and peripheral blood and displays anti-apoptotic properties in malignant T cells. It is, however, unclear exactly which cells express miR-21 and what mechanisms regulate miR-21. Here, we demonstrate miR-21 expression in situ in both malignant and reactive lymphocytes as well as stromal cells. qRT-PCR analysis of 47 patients with mycosis fungoides (MF) and Sezary Syndrome (SS) confirmed an increased miR-21 expression that correlated with progressive disease. In cultured malignant T cells miR-21 expression was inhibited by Tofacitinib (CP-690550), a clinical-grade JAK3 inhibitor. Chromatin immunoprecipitation (ChIP) analysis showed direct binding of STAT5 to the miR-21 promoter. Cytokine starvation ex vivo triggered a decrease in miR-21 expression, whereas IL-2 induced an increased miR-21 expression in primary SS T cells and cultured cytokine-dependent SS cells (SeAx). siRNA-mediated depletion of STAT5 inhibited constitutive- and IL-2-induced miR-21 expression in cytokine-independent and dependent T cell lines, respectively. IL-15 and IL-2 were more potent than IL-21 in inducing miR-21 expression in the cytokine-dependent T cells. In conclusion, we provide first evidence that miR-21 is expressed in situ in CTCL skin lesions, induced by IL-2 and IL-15 cytokines, and is regulated by STAT5 in malignant T cells. Thus, our data provide novel evidence for a pathological role of IL-2Rg cytokines in promoting expression of the oncogenic miR-21 in CTCL.
Assuntos
Regulação Neoplásica da Expressão Gênica/fisiologia , Linfoma Cutâneo de Células T/metabolismo , MicroRNAs/biossíntese , Fator de Transcrição STAT5/metabolismo , Neoplasias Cutâneas/metabolismo , Feminino , Humanos , Linfoma Cutâneo de Células T/genética , Masculino , MicroRNAs/genética , Fator de Transcrição STAT5/genética , Neoplasias Cutâneas/genéticaAssuntos
Regulação Neoplásica da Expressão Gênica , Interleucinas/metabolismo , Linfoma de Células T/metabolismo , MAP Quinase Quinase Quinase 4/metabolismo , Neoplasias Cutâneas/metabolismo , Linfócitos T/metabolismo , Progressão da Doença , Humanos , Inflamação , Interleucinas/genética , Sistema de Sinalização das MAP Quinases , Fosforilação , RNA Interferente Pequeno/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de SinaisRESUMO
Aberrant activation of Janus kinase-3 (Jak3) and its key down-stream effectors, Signal Transducer and Activator of Transcription-3 (STAT3) and STAT5, is a key feature of malignant transformation in cutaneous T-cell lymphoma (CTCL). However, it remains only partially understood how Jak3/STAT activation promotes lymphomagenesis. Recently, non-coding microRNAs (miRNAs) have been implicated in the pathogenesis of this malignancy. Here, we show that (i) malignant T cells display a decreased expression of a tumor suppressor miRNA, miR-22, when compared to non-malignant T cells, (ii) STAT5 binds the promoter of the miR-22 host gene, and (iii) inhibition of Jak3, STAT3, and STAT5 triggers increased expression of pri-miR-22 and miR-22. Curcumin, a nutrient with anti-Jak3 activity and histone deacetylase inhibitors (HDACi) also trigger increased expression of pri-miR-22 and miR-22. Transfection of malignant T cells with recombinant miR-22 inhibits the expression of validated miR-22 targets including NCoA1, a transcriptional co-activator in others cancers, as well as HDAC6, MAX, MYCBP, PTEN, and CDK2, which have all been implicated in CTCL pathogenesis. In conclusion, we provide the first evidence that de-regulated Jak3/STAT3/STAT5 signalling in CTCL cells represses the expression of the gene encoding miR-22, a novel tumor suppressor miRNA.
Assuntos
Janus Quinase 3/metabolismo , Linfoma Cutâneo de Células T/genética , MicroRNAs/antagonistas & inibidores , Fator de Transcrição STAT3/metabolismo , Fator de Transcrição STAT5/metabolismo , Neoplasias Cutâneas/genética , Linhagem Celular Tumoral , Genes Supressores de Tumor , Humanos , Janus Quinase 3/antagonistas & inibidores , Janus Quinase 3/genética , Linfoma Cutâneo de Células T/metabolismo , Linfoma Cutâneo de Células T/patologia , MicroRNAs/administração & dosagem , MicroRNAs/biossíntese , MicroRNAs/genética , Piperidinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/farmacologia , Pirróis/farmacologia , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT5/genética , Transdução de Sinais , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , TransfecçãoRESUMO
Skin lesions from mycosis fungoides (MF) patients display an increased expression of interleukin-15 (IL-15), IL-17F, and other cytokines implicated in inflammation and malignant cell proliferation in cutaneous T-cell lymphoma (CTCL). In the leukemic variant of CTCL, Sézary syndrome (SS), IL-2 and IL-15 trigger activation of the Jak-3/STAT3 pathway and transcription of IL17A gene, whereas it is unknown what causes IL-15 expression, Jak3/STAT3 activation, and production of IL-17F in MF. Here, we studied the expression and regulation of IL-15 and its relation to IL-17F in MF cell lines and skin lesions from 60 MF patients. We show that: (1) the spontaneous IL-15 mRNA expression is resistant to Jak3 and STAT3 inhibitors at concentrations that profoundly inhibit STAT3 activation and IL-17F mRNA expression; (2) anti-IL-15 antibody blocks STAT3 activation induced by exogenous IL-15 in non-malignant MF T cells, whereas the spontaneous STAT3 activation and IL-17F expression in malignant T cells is not inhibited; (3) patients display heterogeneous IL-15/IL-17F mRNA expression patterns in skin lesions; and (4) IL-15 expression (in contrast to IL-17F) is not associated with progressive disease. Taken together, these findings indicate that IL-15 and IL-17F are differentially regulated and expressed in MF. We propose that IL-15 and IL-17F are markers for different inflammatory environments and play distinct roles in the development and progression of MF.
