Work

Epigenetic targeting of an HBO1-H3K9la-CHI3L1 axis reduces regulatory B cell-mediated CD8 + T cell dysfunction in lung adenocarcinoma

Year: 2026

Type: article

Abstract: Background Aberrant glycolysis and lactate accumulation are hallmarks of solid tumors, yet how tumor-derived lactate contributes to tumor progression has not been fully defined. This study intends to examine the role of glycolysis in lung adenocarcinoma (LUAD) growth and immunosuppression, and to explore the underpinning mechanisms.Methods Syngeneic Lewis lung carcinoma models and autochthonous Kras LSL-G12D LUAD mice were used. Glycolysis was inhibited by 2-DG or LDH knockdown, followed by tumor growth and immune-cell composition assessments. Therapeutic anti-IL-35 blockade and CD8+ T depletion were performed using neutralizing antibodies. Chitinase 3-like 1 (CHI3L1) expression, regulatory B cell (Breg) polarization, and B-cell-mediated T-cell suppression were assessed by flow cytometry, RNA sequencing, qPCR, ELISA, immunohistochemistry, and co-culture assays. CUT&Tag, chromatin immunoprecipitation, co-immunoprecipitation, and cell-free transferase assays were used to define the lactylation mechanism.Results Glycolysis restriction suppressed tumor growth and metastatic colonization, reduced CD1d hiCD5+IL-35+ Bregs, and restored GZMB+CD8+ T cells. CHI3L1 was markedly downregulated after glycolysis inhibition, whereas recombinant CHI3L1 restored IL-13Rα2+ Breg polarization and impaired CD8+ T-cell responses through STAT3 activation. Lactate increased H3K9 lactylation and CHI3L1 expression, while glycolysis inhibition reduced H3K9la enrichment at the Chi3l1 promoter. HBO1 directly catalyzed H3K9 lactylation and promoted CHI3L1 production. Genetic or pharmacological HBO1 blockade reduced Bregs, enhanced cytotoxic T-cell activity, and improved the efficacy of anti-PD-1 therapy.Conclusions This study demonstrates the participation of an HBO1-H3K9la-CHI3L1–IL-13Rα2-STAT3 axis in tumor glycolysis-established Breg polarization and CD8 + T dysfunction. Targeting HBO1 may provide a strategy to enhance the efficacy of PD-1 blockade in LUAD.

Source: Journal for ImmunoTherapy of Cancer

DOI: 10.1136/jitc-2026-015190