Expression of microRNA- 942 in liver cancer tissues and its effect on proliferation and invasion of hepatocellular carcinoma

Objective To investigate the expression of microRNA (miRNA, miR)- 942 in liver cancer tissues and its effect on proliferation and invasion of hepatocellular carcinoma (HCC). Methods miR- 942 expression was detected in HCC and peritumoral tissues by real-time quantitative polymerase chain reaction (Real-time PCR) from 70 patients. The Huh7 cells were transfected with scrambled miRNA sequence (negative control group), miR- 942 mimics (miR- 942 mimics group) and miR- 942 inhibitors (miR- 942 inhibitors group) respectively. The proliferative activity and invasion abilities of Huh7cells were measured by methyl thiazol tetrazolium (MTT) and Transwell assays. The expression levels of proliferating cell nuclear antigen (PCNA) and metalloproteinase- 9 (MMP- 9) were detected by Western blotting. Results miR- 942 was significantly up-regulated in HCC tissues as compared with matched peritumoral tissues (0.92±0.08 vs. 0.42±0.05, t=5.712, P=0.000). The results of cell proliferation showed that the absorbance (A) value of Huh7 cells (A) in miR- 942 inhibitors group was significantly lower than that of the negative control group and the miR- 942 mimics group after 5 days (0.79±0.02 vs. 1.02±0.04, t=7.513, P=0.001; 0.79±0.02 vs. 1.51±0.12, t=8.621, P=0.001). The results of Transwell assays showed that the number of metastatic cells in the miR- 942 inhibitors group was significantly decreased compared to the negative control group and the miR- 942 mimics group respectively [(59.13±5.41) cells vs. (97.26±11.13) cells, t=11.712, P=0.000; (59.13±5.41) cells vs. (99.42±12.13) cells, t=12.113, P=0.000]. The expression of PCNA and MMP- 9 protein in miR- 942 inhibitors group was reduced by 80.1%and56.3% respectively (t=5.231, P=0.000; t=6.415, P=0.000). Conclusion The expression of miR- 942 in HCC tissues was significantly higher than that in adjacent tissues, and dysregulation of miR- 942 can suppress proliferation and invasion of HCC cells, which may be related to down-regulation of PCNA and MMP- 9 expression. Key words: Carcinoma, hepatocellular; MicroRNA-942; Proliferation; Invasion