The lactylation of glucose-6-phosphate dehydrogenase promotes malignant phenotypes in cancer cell lines.

BACKGROUND

Malignant tumors are characterized by their reliance on hyperactive glycolysis (Warburg effect), marked by increased glucose uptake, lactate secretion, and preferential glucose flux into glycolysis and the pentose phosphate pathway (PPP). These metabolic shifts provide energy, biosynthetic precursors, and maintain redox balance, supporting tumor proliferation. However, the regulatory crosstalk between glycolysis and PPP remains poorly understood. This study investigates how tumors coordinate these pathways to drive progression via metabolic reprogramming.

METHODS AND RESULTS

Exogenous lactate supplementation in A549 cells increased the NADPH/NADP ratio, enhanced fatty acid synthesis, and upregulated the PPP. Western blotting revealed lactylation of glucose-6-phosphate dehydrogenase (G6PD), which correlated with intracellular lactate levels, modulated by rotenone treatment or lactate dehydrogenase A (LDHA) overexpression. LDHA knockdown significantly reduced G6PD lactylation. Enzyme assays confirmed that lactylation enhanced G6PD activity. Through truncation and mutagenesis analyses, we identified lysines 45-47 as the key lactylation site, which enhances NADP⁺ binding and promotes G6PD dimerization. Mutation of this site impaired cancer cell proliferation and migration in vitro and suppressed tumor growth in vivo. Mechanistically, G6PD lactylation serves as a metabolic switch, linking PPP activation to oncogenic progression.

CONCLUSIONS

Lactate drives tumor progression through G6PD lactylation, activating the PPP and facilitating glycolysis-PPP crosstalk. This study uncovers a novel metabolic rewiring mechanism that promotes oncogenic synergy.