Targeting the MIR4435-2HG/miR-29c-3p/FSP1 axis overcomes lenvatinib resistance by inducing ferroptosis in hepatocellular carcinoma

BACKGROUND: Lenvatinib resistance is a major clinical challenge in advanced hepatocellular carcinoma (HCC). While ferroptosis has emerged as a promising target to overcome therapy resistance, the mechanistic link between ferroptosis and lenvatinib resistance in HCC remains incompletely understood. METHODS: We analyzed clinical data from TCGA-LIHC and performed functional assays in two HCC cell lines. RNA antisense purification sequencing (RAP-seq) was used to identify downstream targets, and the mechanisms were validated by dual-luciferase reporter assays and Western blotting. Ferroptosis was assessed by measuring lipid reactive oxygen species (lipid ROS) and labile iron levels. Therapeutic efficacy was evaluated both in vitro and in vivo. RESULTS: MIR4435-2HG was upregulated in HCC and associated with poorer overall survival. It promoted malignant phenotypes and was further upregulated in lenvatinib-resistant cell lines. Mechanistically, MIR4435-2HG functioned as a competing endogenous RNA (ceRNA) by sponging miR-29c-3p, resulting in upregulation of FSP1. This axis suppressed ferroptosis, thereby conferring lenvatinib resistance. Knockdown of MIR4435-2HG or inhibition of FSP1 synergized with lenvatinib to induce ferroptosis and overcome resistance. The combination strategy significantly suppressed tumor growth in vivo without apparent systemic toxicity. CONCLUSION: Our findings identify a previously uncharacterized MIR4435-2HG/miR-29c-3p/FSP1 axis that promotes lenvatinib resistance by inhibiting ferroptosis, highlighting that targeting this axis may provide a mechanistic basis and preclinical rationale for overcoming lenvatinib resistance in HCC.