miR-31 Modulates Liver Cancer HepG2 Cell Apoptosis and Invasion via ROCK1/F-Actin Pathways

PURPOSE: Liver cancer is one of the most common malignant tumor in the world. miR-31 is downregulated in liver cancer and associated with tumor growth and metastasis. However, the underlying mechanism remains unclear. METHODS: Cellular apoptosis was detected via MTT, TUNEL assay, LDH release and Annexin V/PI flow-cytometry analysis. Cellular migration and invasion were measured by the Transwell chamber assay. Mitochondrial functions were evaluated via mitochondrial membrane potential JC-1 staining and mPTP opening assessment. The mitophagy activity was examined via Western blots. RESULTS: In the present study, our results confirm that miR-31 promotes apoptosis and inhibits proliferation and metastasis in liver cancer HepG2 cells. In vitro, miR-31 promotes HepG2 cell apoptosis through the mitochondrial pathway as indicated by mitochondrial potential reduction, increased mPTP opening time, cty-c release and imbalance of pro- and anti-apoptotic proteins. Furthermore, miR-31 reduces the energy generation by inhibiting mitochondrial respiratory function. At last, it is demonstrated that miR-31 triggers the mitochondrial damage via ROCK1/F-actin pathway. Inhibiting the ROCK1/F-actin pathway abolishes the effects of miR-31 mimic on mitochondrial injury, apoptosis, proliferation arrest and migration inhibition. CONCLUSION: Our results reveal that miR-31 can inhibit HepG2 cell survival and metastasis by activating the ROCK1/F-actin pathway.