[Anti-leukemia mechanism of miR-17 and miR-20a silencing mediated by miRNA sponge].

This study was aimed to quantitatively detect the expression levels of pre-miR-17 and pre-miR-20a in acute leukemia patients and eight kinds of leukemia cell lines, and to investigate the anti-leukemia mechanism of miR-17 and miR-20a silence mediated by miRNA Sponge. Quantitative real-time PCR was used to detect the mRNA expression levels of pre-miR-17 and pre-miR-20a in patients with various types of leukemia and leukemia cell lines. The Jurkat cells over-expressing miR-17 and miR-20a were transfected with recombinant lentivirus-transfecting units targeted at miR-17 and miR-20a plus 6 µg/ml of polybrene. Then the proliferation ability and cell cycle of Jurkat cells was evaluated by CCK-8 and flow cytometry respectively. The results showed that the expression level of pre-miR-17 and pre-miR-20a in all leukemia patients was significantly higher than that in normal group(P < 0.05), the expression of pre-miR-17 and pre-miR-20a in acute lymphoid leukemia was significantly higher than that in acute myeloid leukemia(P < 0.05), and the pre-miR-17 and pre-miR-20a expression level did not correlate significantly with high white blood cell count>20.0×10(9)/L(P > 0.05). The miR-17 and miR-20a silencing mediated by miRNA Sponge led to a significant decrease of cell growth, restored G1 accumulation and increase of cell apoptosis. It is concluded that the expression of miR-17 and miR-20a is upregulated in leukemia patients, which may contribute to leukemogenesis. Over-expressed miR-17 and miR-20a promote cell growth and cell cycle progression, and inhibit apoptosis through negatively-regulating P21 and E2F1 after-transcriptionally.