TRIP13 protects LDHA from FBXW7-mediated degradation and drives glycolytic plasticity in colorectal cancer

Abstract

Abstract Background Metabolic plasticity enables colorectal cancer (CRC) cells to survive hypoxic and therapeutic stress. Lactate dehydrogenase A (LDHA) is a key regulator of glycolysis and lactate production, yet the mechanisms that maintain LDHA protein stability in CRC remain poorly understood. We investigated whether the AAA+ ATPase TRIP13 regulates LDHA proteostasis and metabolic adaptation. Methods TRIP13-interacting proteins were identified by affinity purification–mass spectrometry and validated by co-immunoprecipitation. Protein stability, ubiquitination and FBXW7-dependent regulation of LDHA were examined using genetic, biochemical and purified-protein assays. Glycolytic metabolism, redox homeostasis, H3K18 lactylation (H3K18la), antioxidant gene expression and oxaliplatin response were assessed under hypoxia. The involvement of p300 was evaluated pharmacologically and genetically, and xenograft models were used for in vivo validation. Results LDHA was identified as a TRIP13-associated metabolic protein. TRIP13 depletion reduced LDHA protein abundance and stability while increasing its ubiquitination, with minimal effects on LDHA transcription. Mechanistically, TRIP13 bound LDHA through its AAA+ ATPase-associated region and limited FBXW7 association with LDHA, thereby suppressing FBXW7-dependent ubiquitination and proteasomal degradation. Direct competition was further supported by purified-protein assays. Functionally, TRIP13-dependent LDHA stabilization sustained glycolytic activity and lactate production under hypoxia. Loss of TRIP13 increased oxidative stress and oxaliplatin sensitivity, whereas LDHA restoration, lactate supplementation or FBXW7 depletion partially rescued these effects. Increased lactate promoted a p300-dependent H3K18la-associated antioxidant program involving GCLC and SLC7A11. Consistently, wild-type TRIP13, but not the LDHA-binding-defective TRIP13-ΔAAA+ mutant, restored this metabolic program and promoted xenograft growth. Conclusions TRIP13 promotes CRC metabolic adaptation by protecting LDHA from FBXW7-mediated ubiquitination and degradation. The resulting LDHA–lactate–p300/H3K18la antioxidant program enhances redox homeostasis and oxaliplatin resistance under hypoxic stress. Targeting TRIP13-dependent LDHA stabilization may therefore represent a therapeutic strategy for chemoresistant CRC.