A tumor-derived lactate/ENO1 lactylation feedback loop facilitates osimertinib resistance of lung adenocarcinoma.

Enhanced glycolysis and lactate accumulation are shared features of human cancers. Lactylation is a lactate-derived posttranslational modification. So far, the impact of lactylation on resistance to osimertinib (a third-generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI)) in patients with lung adenocarcinoma (LUAD) remains indistinct. Here, we performed 4D label-free proteomics analysis of LUAD tissues from advanced-stage EGFR-mutant patients treated with surgery with or without neoadjuvant osimertinib to reveal a global lactylation profile and explore the role and molecular mechanism of protein lactylation in resistance to osimertinib. Through scanning the lactylated proteome, we discovered that α-Enolase 1 (ENO1), which acts as a key glycolytic enzyme, underwent lactylation at lysine 89 (K89) in LUAD tissues. The levels of ENO1 lactylation were notably attenuated in LUAD tissues after effective osimertinib treatment and were notably elevated in osimertinib-resistant LUAD cells. We found that monocarboxylate transporters (MCTs) facilitated lactate uptake into LUAD cells for ENO1 lactylation primarily through a p300/CREB-binding protein C (CBP)-dependent mechanism. ENO1 facilitated metabolic reprogramming and lactate production and interacted with several key metabolic enzymes, such as pyruvate kinase M1 (PKM1), pyruvate kinase M2 (PKM2), lactate dehydrogenase B (LDHB), and malate dehydrogenase 2 (MDH2), thus forming a tumor-derived lactate/ENO1 lactylation feedback loop, eventually contributing to osimertinib resistance in LUAD. In the in vivo orthotopic xenograft osimertinib-resistant models, targeted suppression of the tumor-derived lactate/ENO1 lactylation feedback loop effectively ameliorated resistance to osimertinib. Collectively, our findings provide the basis for targeting lactate/lactate-associated signaling to combat resistance to osimertinib.