Inhibition of autophagy impairs free fatty acid-induced excessive lipid accumulation in hepatocellular carcinoma and hepatic cells

Abstract

Autophagy is a reparative life-sustaining process. Dysfunctions of autophagy play an important role in the progression of chronic liver diseases. The role of autophagy in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) is still controversial. This study aimed to analyse the roles and molecular mechanisms of autophagy in NAFLD. In hepatic L02 and liver cancer cells (HuH-7), nonalcoholic fatty liver (NAFL) cell model was induced by free fatty acids (FFA). The cytotoxic effect was measured by MTS assay. Lipid droplets were detected by immunofluorescence assay and flow cytometry. The autophagy-related genes were measured by Western blot analysis. The autophagy inhibitor 3-methyladenine (3-MA) was used to block the autophagy. FFA induced a significant increase in the intracellular content of lipid droplets, and the accumulation of fatty droplets was dose-dependent in L02 and HuH-7 cells. FFA (800 lM) had no cytotoxic effect on L02 and HuH-7 cells. The levels of LC3-II/LC3-I and BECN1 were increased, but the level of p62 was decreased in the NAFL cell models. The expression of these genes was dose-dependent in the NAFL cell models. Intracellular lipid accumulation was associated with the upregulation of LC3-II/LC3-I and BECN1 and the deregulation of p62 in the NAFL cell models. The autophagy inhibitor 3-MA suppressed the FFA-induced autophagy in the NAFL cell models. Furthermore, 3-MA treatment significantly alleviated the accumulation of lipid droplets in L02 and HuH-7 cells. Our results suggest that autophagy has a significant effect on lipid accumulation in the NAFL cell models. Inhibition of autophagy impairs FFA-induced excessive lipid accumulation in hepatocellular carcinoma and hepatic cells.