Analysis of gene expression changes in lipid droplet formation of human liver cancer cell HepG2

Fatty liver is a condition of excessive triglyceride accumulation in hepatocytes. Additionally, hepatocytes showed a high degree of fat droplet accumulation during excessive alcohol consumption and metabolic syndrome. However, the molecular mechanisms involved in fat droplet formation remain unknown. This study used an in vitro fatty liver formation model of the human liver cancer cell line HepG2 to comprehensively search for fat droplet formation-related genes whose expression changes during fat droplet formation. Microarray analysis with extracted total RNA determined the genes that are involved in fat droplet formation and confirmed their expression by real-time polymerase chain reaction after culturing HepG2 cells in a culture medium containing 0, 50, 200, and 500 μM of oleic acid for 24 h. The results revealed 142 genes demonstrating increased expressions by >2.0 fold with oleic acid treatment and 426 genes demonstrating decreased expressions. Perilipin 2 (PLIN2) was estimated as the gene most closely associated with fatty liver. Lipid droplet formation in HepG2 upregulated PLIN2 in an oleic acid-treated concentration-dependent manner. These results indicate the involvement of genes in oleate treatment-induced lipid droplet formation in HepG2, particularly PLIN2 may play an important role. Gene expressions in the HepG2 cell line treated with 0, 50, 200, and 500 μM of oleic acid were examined by microarray analysis.