Abstract: Objective To investigate the effect of microRNA (miR)-425 on the proliferation, migration and invasion of hepatocellular carcinoma cells, and the molecular mechanism. Methods The expression level of miR-425 in hepatocellular carcinoma cell lines (HepG2, SMMC-7721 and MHCC-97H) and normal hepatic cell line (HL-7702) was detected using reverse transcription-quantitative polymerase chain reaction. We predicted the target genes of miR-425 by bioinformatics analysis, and confirmed that protein tyrosine phosphatase, receptor type, N polypeptide 2 (PTPRN2) was directly targeted by miR-425 through dual luciferase reporter assay. The expression level of PTPRN2 protein was examined by western blotting. The effect of miR-425 and PTPRN2 on the proliferation, migration and invasion of hepatocellular carcinoma cells was tested by MTT assay and Transwell assay, respectively. Results The relative expressions of miR-425 in hepatocellular carcinoma cell lines were 2.01 ± 0.13, 3.97 ± 0.24 and 9.14 ± 0.26, which were higher than 1.00 ± 0.03 in normal hepatic cell line (P<0.005). Inhibiting the expression of miR-425 by transfecting miR-425 inhibitor could significantly suppress the proliferation, migration and invasion of hepatocellular carcinoma cells. The luciferase reporter assay showed that miR-425 could reduce the activity of luciferase in wild-type vectors (0.99 ± 0.09 vs 0.40 ± 0.03, P<0.05). But there was no statistically significant difference in mutant vectors (1.00 ± 0.05 vs 0.93 ± 0.07, P>0.05). Knockdown of PTPRN2 could reverse the inhibitory effect of miR-425 inhibitor on the proliferation, migration and invasion of hepatocellular carcinoma cells. Conclusion MiR-425 promotes the proliferation, migration and invasion of hepatocellular carcinoma cells by targeting PTPRN2.

Key words: Hepatocellular carcinoma, MicroRNA-425, Protein tyrosine phosphatase, receptor type, N polypeptide 2, Proliferation, Invasion