Lactate-Induced ZMYM2 K529 Lactylation Stabilizes ZMYM2 and Promotes Platinum Resistance in Ovarian Cancer

Platinum resistance remains a major obstacle in ovarian cancer, yet whether abnormal glycolysis and lactate metabolism drive this phenotype through protein lactylation remains unclear. Here, we investigated the role of lactate-driven protein lactylation in platinum resistance and sought to identify the key effector event involved. Global protein lactylation was assessed by immunohistochemistry in tumor samples from 122 patients with high-grade serous ovarian cancer, and integrated proteomic and lactylomic analyses were performed in fresh frozen tumors from 12 patients, followed by validation in ovarian cancer cell models and functional assays. Platinum resistant ovarian cancer exhibited enhanced glycolysis, increased lactate accumulation, and elevated global protein lactylation, which was associated with platinum resistance and shorter progression free survival. Integrated lactylome profiling identified ZMYM2 K529 lactylation as a platinum resistance associated event, and ZMYM2 was upregulated in platinum resistant tissues and cells. Mechanistically, lactate promoted ZMYM2 K529 lactylation, suppressed ubiquitin-proteasome mediated degradation, and increased ZMYM2 stability and abundance. Functionally, ZMYM2 enhanced cisplatin tolerance, homologous recombination repair, and tolerance to DNA damaging treatments. However, both wild-type ZMYM2 and the K529R mutant restored platinum-resistant phenotypes in ZMYM2-knockdown cells, indicating that K529 lactylation primarily maintains ZMYM2 stability rather than directly determining its downstream pro-resistance activity. Collectively, these findings identify a glycolysis-lactate-ZMYM2 lactylation axis that promotes platinum resistance in ovarian cancer and highlight lactylation-dependent ZMYM2 stabilization as a potential therapeutic vulnerability.