Lactylation‐Driven HECTD2 Limits the Response of Hepatocellular Carcinoma to Lenvatinib

Abstract Drug resistance remains a major hurdle for the therapeutic efficacy of lenvatinib in hepatocellular carcinoma (HCC). However, the underlying mechanisms remain largely undetermined. Unbiased proteomic screening is performed to identify the potential regulators of lenvatinib resistance in HCC. Patient‐derived organoids, patient‐derived xenograft mouse models, and DEN/CCl 4 induced HCC models are constructed to evaluate the effects of HECTD2 both in vitro and in vivo. HECTD2 is found to be highly expressed in lenvatinib‐resistant HCC cell lines, patient tissues, and patient‐derived organoids and xenografts. In vitro and in vivo experiments demonstrated that overexpression of HECTD2 limits the response of HCC to lenvatinib treatment. Mechanistically, HECTD2 functions as an E3 ubiquitin ligase of KEAP1, which contributes to the degradation of KEAP1 protein. Subsequently, the KEAP1/NRF2 signaling pathway initiates the antioxidative response of HCC cells. Lactylation of histone 3 on lysine residue 18 facilitates the transcription of HECTD2. Notably, a PLGA‐PEG nanoparticle‐based drug delivery system is synthesized, effectively targeting HECTD2 in vivo. The NPs achieved tumor‐targeting, controlled‐release, and biocompatibility, making them a promising therapeutic strategy for mitigating lenvatinib resistance. This study identifies HECTD2 as a nanotherapeutic target for overcoming lenvatinib resistance, providing a theoretical basis and translational application for HCC treatment.