ACOT7 promotes HNSCC progression by disrupting the AKT-MDM2-p53 axis

Abstract Background Head and neck squamous cell carcinoma ( HNSCC ) is a prevalent malignancy with poor clinical prognosis. While acyl-CoA thioesterases ( ACOTs ) are recognized as key regulators of lipid metabolism, their contributions to HNSCC pathogenesis are not well understood. ACOT7 is of particular interest as it catalyzes the hydrolysis of arachidonoyl-CoA ( AA-CoA ) to arachidonic acid ( AA ), a lipid mediator known to promote tumor growth and signaling. This study aims to define the functional role of ACOT7 in HNSCC and investigate associated metabolic and molecular changes. Methods The functional role of ACOT7 was examined using an integrated approach, combining analysis of clinical datasets (TCGA and GEO) with in vitro and in vivo experiments. ACOT7 expression was manipulated by siRNA-mediated knockdown or lentiviral overexpression. Effects on malignant phenotypes were assessed using MTT, invasion, migration, colony formation and tumor sphere assays, alongside tumor xenograft models. Transcriptomic profiling, bioinformatic analysis, western blotting, chromatin immunoprecipitation ( ChIP ), and luciferase reporter assays were conducted to explore the downstream pathways and regulatory mechanisms associated with ACOT7. Results ACOT7 expression was significantly higher in HNSCC tumor tissues than in adjacent normal tissues and in HNSCC cell lines than in normal human oral keratinocytes ( NHOK ). Elevated ACOT7 expression was associated with poorer survival in HNSCC and several other cancers. ACOT7 knockdown suppressed malignant phenotypes in vitro and tumor growth in vivo, whereas overexpression had the opposite effects. Intracellular AA levels and tumor-tissue AA and prostaglandin E2 ( PGE 2 ) levels decreased following ACOT7 knockdown and increased following overexpression. ChIP and inhibitor experiments supported MYC involvement in ACOT7 transcriptional regulation. Exogenous AA enhanced colony formation and migration and increased total AKT abundance, whereas AKT depletion reduced colony formation in the presence of AA. ACOT7 knockdown reduced total AKT and p-MDM2 levels and increased p53 protein abundance, while AKT depletion produced similar changes in p-MDM2 and p53. Conclusions ACOT7 promotes malignant phenotypes and alters AA abundance in HNSCC. MYC-associated regulation and changes in total AKT and p-MDM2 levels suggest a potential connection between ACOT7 and growth-related signaling. These findings support further evaluation of ACOT7 as a candidate prognostic biomarker and therapeutic target.