A novel peptide decoy DMp39 targeting mitochondrial metabolism to enhance chemotherapy response.

Abstract

e20720 Background: Chemotherapy resistance remains a major clinical challenge, leading to treatment failure and disease relapse. Although protein acetylation is known to regulate cancer cell survival, the role of mitochondrial acetylation signaling in chemotherapy resistance is poorly understood. Here, we found the novel non-canonical function of mitochondrial dihydrolipoyl transacetylase (DLAT) in regulating chemotherapy response. Methods: An acetylome-focused RNA interference screen was performed to identify acetylation-related regulators of cisplatin resistance. Mechanistic studies included interaction proteomics, mutational analyses, metabolic profiling, and mitochondrial functional assays. Clinical relevance was assessed using tumor specimens from patients treated with chemotherapy or chemoimmunotherapy. The therapeutic potential of a decoy peptide (DMp39) targeting DLAT-MTHFD2 was evaluated in cell line- and patient-derived xenograft (PDX) mouse models. Results: DLAT was identified as a key driver of chemotherapy resistance across multiple cancer types. DLAT directly acetylated methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) at lysine 44, activating tetrahydrofolate metabolism by increasing 10-formyl-tetrahydrofolate levels. This metabolic rewiring induces expression of mitochondrial-encoded cytochrome c oxidase II (MT-CO2), reduces chemotherapy-induced mitochondrial reactive oxygen species, and promotes cancer cell survival during chemotherapy. Elevated DLAT signaling, including MTHFD2 acetylation, was observed in tumors from patients refractory to chemotherapy or chemoimmunotherapy. A decoy peptide, DMp39, which competes with MTHFD2 for acetylation by DLAT, was designed. DMp39 restored chemotherapy sensitivity and significantly suppressed tumor growth in PDX models without overt toxicity. Conclusions: Our study identifies a DLAT-MTHFD2 acetylation axis that mediates mitochondrial metabolic reprogramming as a critical mediator of chemotherapy resistance. Targeting this pathway with the unique decoy peptide DMp39 represents a promising therapeutic strategy to overcome resistance and enhance chemotherapy outcomes.