miR-17 and miR-20a Expression in IL-2 Signaling Pathway in Jurkat T Cells

Resumo

Background: the miR-17-92 cluster is known as an oncogene (oncomiR-1) overexpressed in most cancers. However, recent studies have shown that these miRNAs were downregulated in some cancers. Thus, some or all members of miR-17-92 cluster may have dual activity: apoptosis induction or inhibition. Objectives: For a better understanding of miR-17-92 cluster activities, we focused on the function of mir-17 and mir-20a as two members of miR-17-92 cluster in Jurkat cells activated by phytohemagglutinin (PHA). Materials and Methods: Jurkat cells were stimulated by PHA for 24 h. P-lenti-mico-GFP plasmids containing miR-17 or miR-20a and an empty vector (blank) were transfected into activated Jurkat cells using Lipofectamine 2000 reagent. Cell viability was measured using XTT assay after transfection. Putative targets of these miRNAs were predicted by Targetscan and miRWalk algorithms in JAK/STAT and PI3K/AKT signaling pathways. Then the expression of several putative targets was evaluated by quantitative RT-PCR. Results: Transfection of mir-17 and mir-20a decreased the proliferation in activated Jurkat cells. In silico investigations revealed that mir-17 and mir-20a potentially target JAK1, AKT1 and AKT3. Q-RT-PCR analysis illustrated that these targets were downregulated in Jurkat cells after transfection with miR-17 and miR-20a. Conclusions: According to our findings, it seems that mir-17 and mir-20a expression, two members of miR-17-92 cluster, is dependent on cell condition and cell type; as a result, their ectopic expression in activated Jurkat cells may lead to cell death.