miR-125b suppresses the proliferation of hepatocellular carcinoma cells by targeting Sirtuin7.

Previous studies have shown that microRNAs are involved in many human cancers. However, the role of miR-125b in hepatocellular carcinoma (HCC) has not been fully understood. In our study, we detected the expression of miR-125b using Real-time quantitative-polymerase chain reaction (RT-PCR) and found that the expressions of miR-125b were significantly inhibited in HCC tissues and cell lines. The levels of miR-125b were associated with the degree of HCC malignancy. Otherwise, MTT assay showed that the proliferation was significantly decreased after transfection of miR-125b mimics into HepG2 cells; while the proliferation was significantly increased in HepG2 cells transfected with miR-125b inhibitors. Furthermore, TargetScan was conducted to predict the target gene of miR-125b and Sirtuin7 (SIRT7) was chosen to a potential target gene. And then we used luciferase reporter assay and western blot to confirm that SIRT7 is a direct target gene. Western blot indicated that transfection of miR-125b mimics could significantly inhibit the expression of SIRT7 in HepG2 cells, whereas, transfection of miR-125b inhibitor could significantly increase the expression of SIRT7 in HepG2 cells. These results suggest that miR-125b can inhibit the proliferation of HCC by adjusting the expression of SIRT7 and may be a key element of HCC progression.