FBXO32 ubiquitination of SUFU promotes progression and lenvatinib resistance in hepatocellular carcinoma via hedgehog signaling.

Abstract

Lenvatinib is a prevalent treatment for hepatocellular carcinoma (HCC), yet resistance to the drug significantly limits its effectiveness. This study investigates the role of FBXO32 (F-Box Protein 32) in HCC progression and lenvatinib resistance. Methods: We utilized the GSE211850 and GSE46408 datasets to identify an E3 ubiquitin ligase that is highly expressed in both lenvatinib-resistant HCC cells and HCC tissues. The expression and clinical relevance of this E3 ubiquitin ligase were further validated using lenvatinib-resistant HCC cells, online databases, and HCC clinical tissue samples. The phenotype was verified by cell and animal experiments. Techniques such as RNA sequencing, western blotting, immunofluorescence, Co-immunoprecipitation (Co‑IP), Ubiquitination, and cycloheximide (CHX) chase assay reveal the mechanism. FBXO32 is highly expressed in both lenvatinib-resistant HCC cells and HCC tissues. High FBXO32 expression correlated with increased ALT, AFP levels, larger tumors, and advanced TNM stages, serving as an independent risk factor for overall survival (OS) and recurrence-free survival (RFS). Functional assays demonstrated that FBXO32 overexpression enhanced cell proliferation, stemness, apoptosis resistance, and lenvatinib resistance, while knockdown had opposing effects. KEGG enrichment analysis indicated a link between FBXO32 and the Hedgehog signaling pathway. FBXO32-mediated degradation of SUFU, a Hedgehog pathway inhibitor, activated this pathway. Inhibiting Hedgehog signaling counteracted FBXO32's impact on HCC growth and resistance. Conclusion: FBXO32 is a critical marker for lenvatinib efficacy and HCC prognosis, suggesting that targeting FBXO32 or the Hedgehog pathway could provide innovative strategies for overcoming lenvatinib resistance in HCC.