AMPKα1-mediated ZDHHC8 phosphorylation promotes the palmitoylation of SLC7A11 to facilitate ferroptosis resistance in glioblastoma

Abstract

The cystine/glutamate antiporter SLC7A11, as the key regulator of ferroptosis, functions to transport cystine for glutathione biosynthesis and antioxidant defense. Accumulating evidence has shown that SLC7A11 is overexpressed in multiple human cancers and promotes tumor growth and progression. However, the exact mechanism underlying this key protein remains unclear. In this study, we confirmed that SLC7A11 is S-palmitoylated in glioblastoma, and this modification is required for SLC7A11 protein stability. Moreover, we revealed that ZDHHC8, a member of the protein palmitoyl transferases (PATs), catalyzes S-palmitoylation of SLC7A11 at Cys327, thereby decreasing the ubiquitination level of SLC7A11. Furthermore, AMPKα1 directly phosphorylates ZDHHC8 at S299, strengthening the interaction between ZDHHC8 and SLC7A11, leading to SLC7A11 S-palmitoylation and deubiquitination. Functional investigations showed that ZDHHC8 knockdown impairs glioblastoma (GBM) cell survival via promoting intracellular ferroptosis events, which could be largely rescued by ectopic expression of SLC7A11. Clinically, ZDHHC8 expression positively correlates with SLC7A11 and AMPKα1 expression in clinical glioma specimens. This study underscores that ZDHHC8-mediated SLC7A11 S-palmitoylation is critical for ferroptosis resistance during GBM tumorigenesis, indicating a novel treatment strategy for GBM.