The CHMP4C-IGF2BP3 axis drives osimertinib resistance in lung cancer through ZBP1 mRNA degradation and subsequent necroptosis suppression

Osimertinib (OSI) resistance in lung cancer (LC) remains a major clinical challenge. This study elucidates the role of charged multivesicular body protein 4 C (CHMP4C) in this resistance and its underlying mechanism. OSI-resistant (OR) LC cell lines (PC9/OR, HCC827/OR) were established. CHMP4C was knocked down using short hairpin RNA. Cell viability, clonogenicity, and death were assessed by cell counting kit-8, colony formation, and Annexin V/propidium iodide assays. In vivo tumor growth was evaluated in xenograft models. Mechanistic studies involving necroptosis and RNA regulation were conducted using Western blotting, transmission electron microscopy, RNA immunoprecipitation, co-immunoprecipitation, RNA pull-down, MeRIP-qPCR, luciferase reporter assays, and mRNA stability assays. CHMP4C was upregulated in OR cells. Its knockdown restored OSI sensitivity, inhibited clonogenicity, and promoted cell death both in vitro and in vivo. This effect was mediated by the induction of necroptosis, as evidenced by increased phosphorylated mixed lineage kinase domain-like protein (MLKL) levels and characteristic ultrastructural changes. Mechanistically, CHMP4C bound to and interacted with the RNA-binding protein insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3). The CHMP4C-IGF2BP3 complex subsequently bound to and promoted the degradation of Z-DNA binding protein 1 (ZBP1) mRNA, a key necroptosis sensor. Depletion of ZBP1 rescued the increased necroptosis and OSI sensitivity induced by CHMP4C knockdown. The CHMP4C-IGF2BP3 axis promotes OSI resistance in LC by destabilizing ZBP1 mRNA and suppressing ZBP1-mediated necroptosis. Targeting this pathway represents a promising strategy to overcome OSI resistance in LC.