Evaluating squalene epoxidase association with cholesterol-dependent AKT activation and prognosis in gallbladder cancer.

e16297 Background: Gallbladder cancer (GBC) is a highly aggressive biliary tract tumor with limited therapeutic options and poor prognosis. Metabolic reprogramming, particularly cholesterol metabolism, has emerged as a critical driver of tumor progression. Squalene epoxidase (SQLE), a rate-limiting enzyme in cholesterol biosynthesis, has been implicated in multiple cancers; however, its role and underlying mechanisms in GBC remain largely unclear. Methods: \We analyzed SQLE expression in human GBC tissues and paired adjacent para-tumor tissues using quantitative PCR, western blotting and immunohistochemistry, and evaluated its association with clinicopathological features and patient survival. Kaplan–Meier survival analysis was performed to determine the prognostic significance of SQLE. Stable SQLE knockdown and overexpression cell lines were established, and functional assays including proliferation, migration, and apoptosis assays were conducted in GBC cell lines, as well as SQLE inhibitor treated groups. Cholesterol quantification, Filipin staining were performed to elucidate the mechanistic role of SQLE in cholesterol-mediated AKT activation. In vivo tumorigenicity and therapeutic response were evaluated using a subcutaneous xenograft model in nude mice. Results: SQLE was significantly upregulated in GBC tissues compared with adjacent para-tumor tissues and was positively correlated with advanced TNM stage. High SQLE expression was associated with significantly shorter overall survival. Functional studies demonstrated that knocking down or inhibiting SQLE markedly suppressed GBC cell proliferation, migration, and invasion, while inducing apoptosis, and overexpressing SQLE had the opposite results. Mechanistically, SQLE inhibition reduced intracellular cholesterol levels and attenuated downstream AKT signaling. In vivo, targeting SQLE significantly inhibited tumor growth in subcutaneous xenograft model in nude mice. Conclusions: Our findings identify SQLE as a critical regulator of cholesterol-dependent AKT activation and a potent oncogenic driver in GBC. Targeting SQLE represents a promising therapeutic strategy and prognostic biomarker for patients with gallbladder cancer.