MUC1 drives ferroptosis resistance in ICC via Src‐mediated FSP1 deubiquitination and myristoylation

Abstract Background Intrahepatic cholangiocarcinoma (ICC) exhibits poor prognosis and limited therapeutic options. Ferroptosis represents a promising therapeutic strategy, yet resistance mechanisms remain poorly understood. This study investigated the role of mucin 1 (MUC1) in regulating ferroptosis sensitivity in ICC. Methods Bioinformatic analyses of GEO and TCGA datasets identified ferroptosis‐related factors in ICC. MUC1 expression was validated in ICC cell lines and clinical specimens. Ferroptosis sensitivity was assessed through RSL3‐induced cell death assays, lipid peroxidation measurements, and iron detection. Mechanistic studies employed immunoprecipitation‐mass spectrometry, co‐immunoprecipitation, kinase assays, and deubiquitination assays. In vivo efficacy was evaluated using subcutaneous tumor models. Results MUC1 was identified as a critical ferroptosis suppressor in ICC. MUC1 overexpression conferred RSL3 resistance by inhibiting lipid peroxidation and reducing ferrous iron accumulation, independent of the GPX4‐glutathione pathway. Mechanistically, MUC1 recruited Src kinase, which phosphorylated deubiquitinating enzyme ubiquitin‐specific protease 10 (USP10) at tyrosines 359 and 364, enhancing ferroptosis suppressor protein 1 (FSP1) deubiquitination at lysine 246 and stabilizing FSP1 protein. Concurrently, Src phosphorylated N‐myristoyltransferase 1 (NMT1) at tyrosine 41, augmenting FSP1 membrane localization through myristoylation. This dual mechanism potentiated the FSP1‐ coenzyme Q10 (CoQ10) antioxidant system. MUC1 knockdown significantly enhanced ferroptotic sensitivity in vitro and suppressed tumor growth in vivo. Conclusions MUC1 orchestrates ferroptosis resistance in ICC through the Src‐USP10/NMT1‐FSP1 axis. Targeting this signaling cascade represents a potential therapeutic strategy for overcoming ferroptosis resistance in ICC. Key points MUC1 suppresses ferroptosis in ICC via Src‐mediated post‐translational modifications. Src phosphorylation of USP10 stabilizes FSP1 by removing K48‐linked polyubiquitin. Src activates NMT1 to enhance FSP1 myristoylation and membrane localization.