H2BC9 lactylation modulates esophageal squamous cell carcinoma progression via the Wnt/β-catenin signaling pathway

Lactate, traditionally regarded as a metabolic waste product of glycolysis, has recently emerged as a critical signaling molecule and epigenetic modifier via protein lactylation. However, the functional consequences of histone lactylation in cancer progression remain poorly understood.

We integrated transcriptomic data from TCGA and GEO (GSE188900) with bulk and single-cell RNA-seq analyses to identify lactylation-associated histone variants involved in esophageal squamous cell carcinoma (ESCC). Functional assays, immunoprecipitation (IP), western blotting (WB), chromatin immunoprecipitation (ChIP)-qPCR, and luciferase reporter assays were employed to investigate the role of H2BC9 and its lactylation in ESCC. A xenograft tumor model was used to validate in vivo relevance.

We identified H2BC9, a histone H2B variant, as a lactylation-associated oncogene that is overexpressed in ESCC and correlates with poor prognosis. Lactate stimulation induced H2BC9 lactylation, particularly at lysine 44 (K44), as confirmed by mass spectrometry and IP-WB assays. Mechanistically, K44 lactylation of H2BC9 enhanced the transcriptional activity of Wnt7b, leading to activation of the Wnt/β-catenin pathway. Mutation of K44 (K44R) abolished H2BC9 lactylation and significantly impaired its ability to promote ESCC cell proliferation and Wnt7b transcription, as demonstrated by ChIP-qPCR and dual-luciferase assays. In vivo, H2BC9 K44R-expressing cells exhibited reduced tumor growth in xenograft models. Furthermore, H2BC9 expression was associated with an immunosuppressive tumor microenvironment and chemoresistance.

Our study reveals a novel regulatory axis in which H2BC9 K44 lactylation activates Wnt7b transcription and downstream Wnt/β-catenin signaling, driving ESCC progression. Targeting H2BC9 lactylation may offer a promising therapeutic strategy to overcome tumor growth and immune evasion in ESCC.