MiR-122 induces apoptosis of glioma cells by targeting RUNX2

YANG Caidi; WANG Lijuan; ZENG Dinghua; ZHU Jianmei

doi:10.3969/j.issn.1009-0460.2019.02.006

Abstract：Objective To investigate the effect of microRNA122 (miR-122) on apoptosis of glioma cells and its possible molecular mechanism. Methods The expression of miR-122 in human normal astrocyte lines HA1800 and glioma cell lines U251, U87, SHG44 and MO59 K was detected by quantitative fluorescence PCR (QPCR). Dual luciferase reporter assay was used to evaluate the targeting effect of miR-122 on RUNX2. MiR-122 mimics (miR-122 group) and negative control NC (NC group) were transfected into U251 cells. Apoptosis was detected by flow cytometry. Western blotting was used to detect the expression of Bcl-2, Bax and cleaved caspase-3 protein in two groups. MiR-122 mimics and siRUNX2 (MiR-122 + siRUNX2 group) were simultaneously transfected into U251 cells. Apoptosis was detected by flow cytometry. Results The expression of miR-122 in U251, U87, SHG44 and MO59 K cell lines were 0. 34±0. 052, 0. 65±0. 061, 0. 59±0. 071 and 0. 69±0. 098, which was significantly lower than that of human normal astrocyte lines HA1800 (1. 17±0. 173), and the difference was statistically significant (P＜0. 05).MiR-122 inhibited the luciferase activity of wild-type RUNX2 3'UTR reporter gene vector, but had no effect on the luciferase activity of mutant RUNX2 3'UTR reporter gene vector. The apoptotic rate of U251 cells in miR-122 group was (23. 77 ± 0. 83) ％, higher than that in NC group (6. 17 ± 0. 12) ％, lower than that in miR-122+siRUNX2 group (70. 85±0. 35) ％.The difference was statistically significant (P＜0. 05). Western blotting results showed that the expression of RUNX2 protein in the miR-122 group was 0. 57 ± 0. 048, which was lower than that in the NC group (1. 21±0. 19), with statistical significance (P＜0. 05). Compared with NC group, the expressions of Bax and cleaved caspase-3were significantly up-regulated in miR-122 group, while Bcl-2 was significantly down-regulated (P＜0. 05). Conclusion MiR-122 can promote the activation of mitochondrial apoptosis pathway by targeting RUNX2, thereby promoting apoptosis of glioma cells.