SOAT1 enhances lung cancer invasion through stimulating AKT-mediated mitochondrial fragmentation.

Sterol O-acyltransferase 1 (SOAT1) is a key enzyme in lipid metabolism, which mediates cholesterol esterification metabolism and is closely associated with many cancers. However, the role of SOAT1 in lung cancer invasion remains unclear. We found that SOAT1 expression was positively correlated with lung cancer invasion. Downregulation of SOAT1 inhibited invasion, mitochondrial fragmentation, AKT phosphorylation, and phospho-Drp (Ser616) in lung cancer cells and promoted intracellular free cholesterol accumulation. Mechanistically, AKT phosphorylation inhibitor MK-2206 alleviated both SOAT1 overexpression or high expression-induced mitochondrial fragmentation and lung cancer cell invasion. Furthermore, intracellular free cholesterol accumulation reduced AKT phosphorylation, SREBP1 mRNA expression, cell invasion, and mitochondrial fragmentation in lung cancer cells with high SOAT1 expression. In summary, our findings suggest that SOAT1 promotes lung cancer invasion activates the PI3K/AKT signaling pathway by downregulating intracellular free cholesterol levels, thereby affecting the regulation of mitochondrial fragmentation.