KEAP1 loss-of-function suppresses immunogenic ferroptosis and limits PD-1 blockade efficacy through an NRF2-FSP1 pathway

Background Loss-of-function mutations in KEAP1 frequently occur in lung adenocarcinoma and are associated with poor prognosis and limited benefit from immunotherapy. However, the mechanisms linking KEAP1 deficiency to immune evasion remain elusive. Methods We combined patient data analysis, in vivo tumor models, and in vitro co-culture systems to investigate how KEAP1 deficiency shapes dendritic cell (DC) biology and response to PD-1 blockade. Ferroptosis induction assays, damage-associated molecular patterns (DAMPs) quantification, cytokine profiling, and mechanistic interrogation of the FSP1-CoQ10 axis were performed to delineate underlying pathways. Results Clinically, KEAP1 mutations correlated with poor response to PD-1 blockade and reduced DC infiltration. In murine models, KEAP1-deficient tumors exhibited marked resistance to anti-PD-1 therapy. Mechanistically, KEAP1 loss impaired DC function in vitro, as evidenced by reduced maturation, phagocytosis, and naïve CD8 + T-cell priming capacity. This defect was linked to two complementary mechanisms. First, KEAP1-deficient tumor cells resisted ferroptosis and failed to release immunogenic DAMPs, including extracellular ATP, HMGB1, and calreticulin. Second, KEAP1 deficiency reprogrammed the cytokine secretion profile, with downregulation of CCL2, IL-6, CXCL1, and CXCL2, thereby diminishing DC recruitment and inflammatory signaling. Notably, inhibition of the FSP1-CoQ10 antioxidant axis restored ferroptosis-associated immunogenic cell death. Conclusions Our study identifies KEAP1 deficiency as a driver of immune-cold tumor microenvironments and resistance to PD-1 blockade, acting through impaired ferroptosis-induced immunogenic cell death and disrupted DC function. Targeting the FSP1-CoQ10 pathway may restore DC function and sensitize KEAP1-mutant lung cancers to immunotherapy.