Targeting the lactate-lactylation-glucose uptake axis: Cryptotanshinone reprograms metabolic-epigenetic crosstalk in gastric cancer.

Gastric cancer remains a leading cause of cancer-related mortality worldwide, with chemotherapy resistance and severe side effects posing significant challenges. Metabolic reprogramming, particularly lactate-driven histone lactylation, plays a crucial role in tumor progression. Cryptotanshinone (CTS), a bioactive compound from Salvia miltiorrhiza, has demonstrated anti-tumor properties, yet its mechanisms in regulating lactate metabolism and lactylation in gastric cancer remain unclear. This study aimed to elucidate the molecular mechanisms by which CTS inhibits gastric cancer progression, focusing on its effects on enolase activity, lactate production, histone lactylation, and downstream metabolic-epigenetic regulation. We screened Salvia miltiorrhiza ethanol extract (SME) and identified CTS as a key component targeting enolase. Molecular docking, surface plasmon resonance, and limited proteolysis-mass spectrometry were used to confirm CTS-ENO1 interaction. In vitro and in vivo models, including cell lines, xenografts, and patient-derived organoids, were employed to assess anti-tumor effects. Glycolytic function, histone lactylation, and gene expression were evaluated via seahorse assay, western blot, Cut&Tag, and RNA-seq. CTS directly binds to and inhibits enolase ENO1, reducing phosphoenolpyruvate (PEP) and lactate production. Decreased lactate levels led to reduced global histone lactylation, particularly at H3K18. CTS also enhanced HDAC2-mediated de-lactylation by lowering PEP, which otherwise inhibits HDAC2. Downregulation of H3K18la suppressed MGAT4A expression, impairing GLUT1 membrane localization and glucose uptake, thereby forming a feedback loop that inhibits glycolysis. CTS significantly suppressed tumor growth in xenograft and patient-derived organoid models, effects reversible by exogenous lactate.