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.