The mechnism and effect of microRNA-518b on cell proliferation, apoptosis and invasion in hepatocellular carcinoma cell

Objective To investigate the effect of microRNA (miRNA, miR)-518b on proliferation, apoptosis and invasion of hepatocellular carcinoma cells. Methods The miR-518b expression was measured by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) in hepatocellular carcinoma and normal hepatocyte lines. HepG2 cell line was divided into miR-518b over-expressed group (miR-518b group), negative control group (miR-Con group) and blank control group (Blank group). Methyl thiazol tetrazolium (MTT) assay, flow cytometry and Transwell assay were used to measure cell proliferation, apoptosis and invasion. The activity of cysteinyl aspartate-specific protease (Caspase)-3, Caspase-8 and Caspase-9 was determined by spectrophotometry, and the expression of Rap1b protein was determined by Western blotting. T-test was used for comparison of measurement data. Results The expression of miR-518b in hepatocellular carcinoma cell lines was lower than that in normal hepatocellular cell line (P 0.05). The number of invasive cells in miR-518b group was less than that in miR-Con group and Blank group (74±10 vs. 151±15 vs. 153±12, t=17.276, P<0.05). The expression of Rap1b protein in miR-518b group was lowest in three groups (0.38 ± 0.03 vs. 1.03±0.06 vs. 1.05±0.04, t=19.642, P<0.05). Conclusion The down-regulation of the expression of miR-518b was founded in hepatocellular carcinoma cell lines. Over-expression of miR-518b inhibits cell proliferation and invasion, and induce apoptosis. The mechanism may be related to the up-regulation of Caspase-3, Caspase-9 expression and the down-regulation of Rap1b expression. Key words: MicroRNA-518b; Hepatocellular carcinoma; Proliferation; Apoptosis; Invasion