ZDHHC2‐Dependent Palmitoylation Dictates Ferroptosis and Castration Sensitivity in Prostate Cancer via Controlling ACSL4 Degradation and Lipid Peroxidation

Abstract Ferroptosis represents a promising vulnerability to overcome therapeutic resistance in castration‐resistant prostate cancer (CRPC). While S‐palmitoylation of lipid peroxide‐scavenging proteins such as GPX4 and SLC7A11 has been shown to suppress ferroptosis, whether palmitoylation modulates the lipid peroxidation generation remains unclear. Here, we identified the palmitoyltransferase ZDHHC2 as a critical driver of enzalutamide resistance through destabilizing ACSL4. ZDHHC2 is transcriptionally upregulated by a FOXA1/CXXC5/TET2 complex and promotes S‐palmitoylation of the deubiquitinase USP19, which impairs its interaction with ACSL4. This disrupts USP19‐mediated ACSL4 stabilization, promoting its ubiquitin–proteasome degradation and consequently suppressing lipid peroxidation and ferroptosis. We synthesized a small‐molecule ZDHHC2 inhibitor, TTZ1, which restores ACSL4 protein, reactivates ferroptosis, and reverses enzalutamide resistance in CRPC cell lines and patient‐derived xenograft models. This study uncovers a previously unrecognized mechanism by which palmitoylation regulates ferroptosis through modulating ACSL4 stability, and highlights the ZDHHC2‐USP19‐ACSL4 axis as a druggable target for overcoming resistance in advanced prostate cancer.