Functional reprogramming of neutrophils within the brain tumor microenvironment by hypoxia-driven histone lactylation

Despite functional heterogeneity, high frequency of intratumoral neutrophils predicts poor clinical outcomes. The tumor microenvironment reprograms neutrophils into immunosuppressive subsets that hinder anti-cancer immunity, thereby contributing to tumor growth and resistance to immunotherapies. However, the mechanisms underlying neutrophil reprogramming remain elusive. Here, we report that the immunosuppressive ability of brain tumor-infiltrating neutrophils was restricted to a highly glycolytic and long-lived subset expressing CD71, which acquired immunosuppressive properties in response to hypoxia. Mechanistically, hypoxia boosted glucose metabolism in CD71+neutrophils, leading to high lactate production. Lactate caused histone lactylation, which subsequently regulated arginase-1 expression, required for T cell suppression. Targeting histone lactylation with the anti-epileptic drug isosafrole blocked CD71+neutrophil immunosuppressive ability, delayed tumor progression and sensitized brain tumors to immunotherapy. A distinctive gene signature characterizing immunosuppressive CD71+neutrophils correlated with adverse clinical outcomes across diverse human malignancies. This study identifies histone lactylation as a potential therapeutic target to counteract neutrophil-induced immunosuppression within tumors.