BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) displays heterogeneous responses to lenvatinib, with tumor microenvironment (TME) stiffness emerging as a key resistance modulator. This study investigates how tumor peripheral stiffness governs lenvatinib efficacy via mitochondrial fission/mitophagy and evaluates matrix-targeting combination therapies.
METHODS: Clinical HCC tissues underwent stiffness measurement (atomic force microscopy [AFM]/rheometry) and survival correlation analyses., cells grown on softstiff hydrogels (515 kPa) were assessed for their lenvatinib response, mitophagy, and mitochondrial fission 1 (FIS1)-trimethylation of histone H3 lysine 27 (H3K27me3) regulation. Subcutaneous xenografts received collagenase-lenvatinib combination therapy. In vitro vs. vs.
RESULTS: Elevated tumor peripheral stiffness, quantified by AFM and rotational rheometry, was significantly associated with HCC recurrence. Patients with stiff peripheries exhibited reduced recurrence-free survival (<0.05), correlating with upregulated mitophagy markers (Parkin and FIS1) and diminished H3K27me3 in high-stiffness human HCC tissues (<0.0001)., HCC cells on stiff matrices (15 kPa) showed attenuated lenvatinib-induced apoptosis (TUNEL:= 0.0003soft 5 kPa) and preserved mitochondrial membrane potential (JC-1:= 0.0004), concomitant with fragmented mitochondria driven by FIS1 upregulation via H3K27me3 depletion at its promoter (chromatin immunoprecipitation:<0.0001). FIS1 knockdown reversed mitochondrial fragmentation (<0.001) and resensitized cells to lenvatinib. Stiffness amplified cytoprotective mitophagy under lenvatinib stress, evidenced by enhanced LC3/TOM20 colocalization (= 0.0008) and mitochondrial Parkin accumulation., collagenase-mediated matrix softening synergized with lenvatinib, suppressing tumor growth (volume:<0.001; weight:<0.001) while reducing FIS1/Parkin expression and augmenting apoptosis. p p In vitro p vs. p p p p In vivo p p
CONCLUSIONS: Tumor peripheral stiffness drives lenvatinib resistance in HCC via H3K27me3-mediated FIS1 upregulation, triggering mitochondrial fission and cytoprotective mitophagy to evade drug-induced apoptosis. Targeting matrix stiffness (via collagenase-mediated softening) synergizes with lenvatinib to overcome microenvironment-driven resistance, providing a novel mechanoadjuvant strategy for HCC therapy.
IMPACT AND IMPLICATIONS: This study shows that tumor peripheral matrix stiffness reduces lenvatinib sensitivity in HCC by enhancing FIS1-dependent mitophagy, explaining therapeutic response heterogeneity. These findings are clinically relevant, highlighting tumor stiffness as a potential biomarker for lenvatinib resistance and mitophagy as a targetable pathway. Clinically, stiffness assessments (imaging/biopsy) could be used to stratify patients for personalized treatment. Combining lenvatinib with matrix-softening agents or mitophagy inhibitors could improve efficacy. However, translational potential requires validation in larger cohorts and development of non-invasive stiffness measurement methods, given challenges associated with the clinical application of current invasive techniques or collagenase-based preclinical models. e.g.
