LDHC4 promotes ovarian cancer progression through H4K12 lactylation to regulate PGK1 expression and modulate glycolysis.

OBJECTIVE: Ovarian cancer (OC) pathogenesis involves metabolic and epigenetic alterations, yet the underlying mechanisms remain unclear. Here, we sought to investigate the role and regulatory mechanism of lactate dehydrogenase C4 (LDHC4) in OC progression. METHODS: Multi-omics approaches were employed, including analyses of The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) cohorts, tissue microarrays, molecular biology experiments, and in vivo mouse models. LDHC4 expression was modulated in OC cell lines (A2780 and ES-2) to assess its effects on proliferation, migration, invasion, and metastasis. Lactylproteomic profiling, cleavage under targets and tagmentation (CUT&Tag), and chromatin analyses were conducted to explore epigenetic mechanisms. The functional role of the downstream glycolytic enzyme phosphoglycerate kinase 1 (PGK1) was examined using pharmacological inhibition. Molecular docking and xenograft models were used to evaluate the therapeutic potential of targeting H4K12lac (lactylation of histone H4 at lysine 12). RESULTS: LDHC4 was significantly overexpressed in OC tissues and associated with poor overall survival (OS) (hazard ratio [HR] = 4.017, 95% confidence interval [CI]: 2.308–6.989, P < 0.0001). It promoted proliferation, migration, invasion, and metastasis in vitro and in vivo. LDHC4 overexpression increased global lactylation, notably upregulating H4K12lac, which was enriched at the PGK1 promoter. Inhibition of PGK1 with CBR-470-1 (half-maximal inhibitory concentration [IC₠₀] = 14.56 µM) suppressed OC growth and metastasis. Importantly, Elbasvir, identified as a high-affinity H4K12lac inhibitor, significantly reduced tumor burden in mouse xenografts across multiple doses (10–20 mg·kg⁻¹) and downregulated H4K12lac and Ki-67 expression. CONCLUSION: We conclude that LDHC4 promotes OC progression via lactylation-mediated epigenetic upregulation of PGK1. Targeting this pathway through H4K12lac inhibitors such as Elbasvir thus emerges as a viable therapeutic approach for OC.