LCAT deficiency promotes hepatocellular carcinoma progression and lenvatinib resistance by promoting triglyceride catabolism and fatty acid oxidation

Lecithin cholesterol acyltransferase (LCAT), a crucial enzyme in lipid metabolism, plays important yet poorly understood roles in tumours, especially in hepatocellular carcinoma (HCC). In this study, our investigation revealed that LCAT is a key downregulated metabolic gene and an independent risk factor for poor prognosis in patients with HCC. Functional experiments showed that LCAT inhibited HCC cell proliferation, migration and invasion. Mechanistically, LCAT interacts with caveolin-1 (CAV1) to promote the binding of CAV1 to PRKACA and inhibit its phosphorylation, thereby inhibiting triglyceride (TAG) catabolism. On the other hand, LCAT inhibits fatty acid oxidation (FAO) by interacting with CPT1A to promote its ubiquitination and degradation. These events result in an inadequate supply of raw materials and energy and inhibit the malignant behaviours of HCC cells. In addition, LCAT is a reliable predictive biomarker for the efficacy of lenvatinib treatment in HCC patients, and the inhibition of FAO can increase lenvatinib sensitivity in patients with LCATlow HCC. This study revealed that LCAT plays a critical role in the regulation of lipid metabolic reprogramming and is a reliable predictive biomarker for the efficacy of lenvatinib treatment in HCC patients.