Non-canonical dihydrolipoyl transacetylase promotes chemotherapy resistance via mitochondrial tetrahydrofolate signaling.

Chemotherapy is often a primary treatment for cancer. However, resistance leads to therapeutic failure. Acetylation dynamics play important regulatory roles in cancer cells, but the mechanisms by which acetylation mediates therapy resistance remain poorly understood. Here, using acetylome-focused RNA interference (RNAi) screening, we find that acetylation induced by mitochondrial dihydrolipoyl transacetylase (DLAT), independent of the pyruvate dehydrogenase complex, is pivotal in promoting resistance to chemotherapeutics, such as cisplatin. Mechanistically, DLAT acetylates methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) at lysine 44 and promotes 10-formyl-tetrahydrofolate (10-formyl-THF) and consequent mitochondrially encoded cytochrome c oxidase II (MT-CO2) induction. DLAT signaling is elevated in cancer patients refractory to chemotherapy or chemoimmunotherapy. A decoy peptide DMp39, designed to target DLAT signaling, effectively sensitizes cancer cells to cisplatin in patient-derived xenograft models. Collectively, our study reveals the crucial role of DLAT in shaping chemotherapy resistance, which involves an interplay between acetylation signaling and metabolic reprogramming, and offers a unique decoy peptide technology to overcome chemotherapy resistance.