Berberine upregulates miR-22-3p to suppress hepatocellular carcinoma cell proliferation by targeting Sp1

MicroRNA-22-3p (miR-22-3p) is downregulated in hepatocellular carcinoma (HCC), which contributes to the development and progression of HCC. In this study, berberine treatment upregulated miR-22-3p expression in HepG2 cells. Therefore, we investigated whether berberine suppresses the proliferation of HCC cells and explored the underlying mechanism. The HCC HepG2 cell line was treated with a gradient of berberine concentrations (0-300 μM) for 48 h, and 100 μM berberine inhibited cell growth at 24 h. The HepG2 cells were then incubated with 100 μM berberine for 0-48 h, and after treatment for 24 h, berberine markedly suppressed HepG2 cell growth and significantly upregulated miR-22-3p expression. Berberine also downregulated the expression of SP1, CCND1, and BCL2, determined with western blotting. Dual luciferase reporter assays and western blot analyses showed that miR-22-3p directly targeted SP1, thereby suppressing the expression of its downstream targets, CCND1 and BCL2. SP1 knockdown with small interfering RNA also reduced CCND1 and BCL2 expression in HepG2 cells. Therefore, we conclude that berberine treatment suppresses cancer cell growth by regulating miR-22-3p and SP1 and its downstream targets, CCND1 and BCL2, in HCC.