Abstract

Hepatocellular carcinoma (HCC) evades anti-PD-1 immunotherapy via an immunosuppressive microenvironment, where lactate links metabolic reprogramming to epigenetic regulation. We analyzed pan-lysine lactylation and H3K18 lactylation (H3K18la) in 89 HCC patient pairs, and validated functional mechanisms using glycolysis inhibition, HCC-CD8 + T cell co-cultures, and rescue assays. In vivo efficacy was assessed in subcutaneous and orthotopic HCC mouse models. H3K18la levels were elevated in HCC, correlating with advanced staging and poor prognosis. Lactate induced H3K18la to transcriptionally upregulate KIF20A, which stabilized the c-Myc/PD-L1 axis and suppressed cytotoxic T cell function. Combined glycolysis inhibition and anti-PD-1 therapy reversed this immunosuppression and synergistically inhibited tumor growth. This study identifies an H3K18la-KIF20A/PD-L1 axis as a key metabolic-epigenetic checkpoint, highlighting glycolysis targeting as a promising strategy to enhance anti-PD-1 responses in HCC.