miR-651-3p Enhances the Sensitivity of Hepatocellular Carcinoma to Cisplatin via Targeting ATG3-Mediated Cell Autophagy

Drug resistance is a major challenge for hepatocellular carcinoma (HCC) treatment in a clinic, which limits the therapeutic effect of the chemotherapeutic drugs, including cisplatin (CDDP), in this disease. Mounting evidence has identified that miRNAs dysfunction is related to the resistance of tumor cells to CDDP, and miR-651-3p has been identified as a tumor inhibitor to suppress the progression of multiple tumors. However, the role of miR-651-3p in HCC remains unclear. In this study, the relative expression of miR-651-3p in HCC tissues and cell lines were measured, and the functions of miR-651-3p were also observed by CCK-8 assay, flow cytometry assay, and Western blot. Moreover, the downstream target of miR-651-3p was predicted and verified via TargetScan and dual-luciferase reporter assay, and its functions were also investigated. The results showed that miR-651-3p was significantly downregulated in HCC tissues and cell lines, and the decreased miR-651-3p was also observed in CDDP-induced cells. miR-651-3p upregulation could effectively inhibit the proliferation and induce the apoptosis of R-HepG2. It was also found that ATG3 was a downstream target of miR-651-3p, and ATG3 was highly upregulated in HCC tissues. Moreover, the upregulated ATG3 could partly reverse the effects of miR-651-3p on R-HepG2. Besides, miR-651-3p involved the autophagy pathway of the HCC cells via targeting ATG3. In conclusion, miR-651-3p could regulate the autophagy to enhance the sensitivity of HepG2 cells to CDDP via targeting ATG3.