Royal jelly acid suppresses hepatocellular carcinoma tumorigenicity by inhibiting H3 histone lactylation at H3K9la and H3K14la sites

BACKGROUND AND PURPOSE: Human hepatocellular carcinoma (HCC) features include enhanced glycolysis and elevated lactate concentrations. Accumulation of lactate during metabolism provides a precursor for histone lysine modification. This study was designed to determine whether royal jelly acid (RJA) acts against HCC through the lactate modification pathway. EXPERIMENTAL APPROACH: The effects of RJA on Hep3B and HCCLM3 cell invasion, migration, proliferation, and apoptosis were investigated using cell scratching, colony formation assay, flow cytometry, western blotting, and real-time qPCR, gas chromatography, and RNA sequencing to determine the pathways and molecular targets involved. Tumor xenografts were used to evaluate the anti-HCC effects of RJA in vivo. In-cell Western blotting and expression correlation analysis were applied to confirm the associations between H3 histone lactylation and the antitumor effects of RJA. KEY RESULTS: RJA has good antitumor effects in vivo and in vitro. Multi-omics analysis with metabolome and transcriptome determined that the glycolytic metabolic pathway provided the principle antitumor effect of RJA. Further mechanistic studies showed that RJA inhibited HCC development by interfering with lactate production and inhibiting H3 histone lactylation at H3K9la and H3K14la sites. CONCLUSIONS AND IMPLICATIONS: This study first demonstrated that RJA exerts antitumor effects by affecting the glycolytic pathway. RJA could regulate the lactylation of H3K9la and H3K14la sites on H3 histone using lactate as a clue in the glycolytic pathway. Therefore, the lactylation of H3 histone is vital in exerting the antitumor effect of RJA, providing new evidence for screening and exploring antitumor drug mechanisms in the later stage.