Targeting eEF2K induces oxidative stress and sensitizes cancer cells to ferroptosis induction

Eukaryotic elongation factor 2 kinase (eEF2K), a calcium/calmodulin-dependent protein kinase, exhibits paradoxical activation and overexpression in numerous tumors, suggesting a potential advantageous role for cancer cells. eEF2K phosphorylates and inactivates its downstream target, eukaryotic elongation factor 2 (eEF2), thereby negatively regulating protein synthesis. Despite being a translation inhibitor, eEF2K inhibition alone has demonstrated limited anti-cancer efficacy. This study investigates a novel approach to targeting eEF2K in cancer therapy, exploring its potential beyond its established role in protein synthesis regulation. We found that pharmacological inhibition of eEF2K using A484954 resulted in minimal cytotoxicity but effectively reduced eEF2 phosphorylation. Surprisingly, eEF2K inhibition impaired de novo protein synthesis and induced mild oxidative stress across multiple cancer cell lines. Furthermore, eEF2K inhibition compromised cellular antioxidant defenses, leading to enhanced ROS accumulation when challenged with oxidative stressors. Notably, eEF2K inhibition potentiated ferroptosis induction and lipid peroxidation when combined with ferroptosis inducers or glutathione depletion. These findings were corroborated by eEF2K silencing, which similarly increased basal ROS levels, enhanced sensitivity to oxidative stress, and promoted ferroptosis. Our results reveal a previously unrecognized role of eEF2K in maintaining redox homeostasis and suggest that targeting eEF2K may be a promising strategy to sensitize cancer cells to ferroptosis-inducing therapies.