H3K18 Lactylation Potentiates Immune Escape of Non–Small Cell Lung Cancer

Recently discovered epigenetic modification lysine lactylation contributes to tumor development and progression in several types of cancer. In addition to the tumor-intrinsic effects, histone lactylation may mediate tumor microenvironment remodeling and immune evasion. In this study, we observed elevated pan-lysine lactylation and histone H3 lysine 18 lactylation (H3K18la) levels in non-small cell lung cancer (NSCLC) tissues, which was positively correlated with poor patient prognosis. Interruption of glycolysis by 2-deoxy-D-glucose and oxamate treatment and silencing of lactate dehydrogenase A and lactate dehydrogenase B reduced H3K18la levels and circumvented immune evasion of NSCLC cells by enhancing CD8+ T-cell cytotoxicity. Mechanistically, H3K18la directly activated the transcription of pore membrane protein 121 (POM121), which enhanced MYC nuclear transport and direct binding to the CD274 promoter to induce PD-L1 expression. In a mouse NSCLC xenograft model, combination therapy with a glycolysis inhibitor and an anti-PD-1 antibody induced intratumoral CD8+ T-cell function and exhibited strong antitumor efficacy. Overall, this work revealed that H3K18la potentiates the immune escape of NSCLC cells by activating the POM121/MYC/PD-L1 pathway, which offers insights into the role of posttranslational modifications in carcinogenesis and provides a rationale for developing an epigenetic-targeted strategy for treating NSCLC. Significance: H3K18 lactylation supports immunosuppression in non-small cell lung cancer by inducing POM121 to increase MYC activity and PD-L1 expression, which can be reversed by metabolic reprogramming and immunotherapy treatment.