ZDHHC9 regulates lipid metabolic reprogramming by mediating palmitoylation of ACSL3 to promote Cetuximab resistance in Colorectal Cancer.

Tumor metastasis and drug resistance are the leading causes of mortality in patients with colorectal cancer (CRC). Protein palmitoylation exerts a pivotal role in the metabolic reprogramming across various malignancies. However, the precise mechanisms underlying its contribution to CRC metastasis and drug resistance via lipid metabolism reprogramming remain elusive. Therefore, this study aimed to elucidate the specific role of ZDHHC9 in conferring Cetuximab resistance in CRC. Initial phenotypic screening with the broad-spectrum inhibitor 2-BP implicated palmitoylation in Cetuximab resistance. Subsequently, targeted genetic experiments identified ZDHHC9 as the specific molecular driver. Furthermore, ZDHHC9 was significantly upregulated in CRC tissues and strongly correlated with poor patient prognosis. Subsequent in vitro and in vivo experiments demonstrated that ZDHHC9 functionally promoted Cetuximab resistance in CRC. Mechanistically, ZDHHC9 physically interacted with ACSL3 and enhanced its palmitoylation, thereby driving the malignant progression of CRC. Moreover, we identified cysteine 468 (C468) as the critical residue responsible for the palmitoylation of ACSL3. Notably, ectopic overexpression of ACSL3 effectively rescued the suppression of CRC cell proliferation induced by ZDHHC9 depletion. In conclusion, our findings establish the ZDHHC9-ACSL3 axis as a preclinically validated resistance driver and an actionable metabolic vulnerability for overcoming Cetuximab resistance in CRC.