MTHFD2 Enhances cMYC O-GlcNAcylation to Promote Sunitinib Resistance in Renal Cell Carcinoma

Sunitinib is a first-line targeted therapy for patients with renal cell carcinoma (RCC), but resistance represents a significant obstacle to the treatment of advanced and metastatic RCC. Metabolic reprogramming is a characteristic of RCC, and changes in metabolic processes might contribute to resistance to sunitinib. In this study, we identified methylenetetrahydrofolate dehydrogenase 2 (MTHFD2), a mitochondrial enzyme involved in one-carbon metabolism, as a critical mediator of sunitinib resistance in RCC. MTHFD2 was elevated in sunitinib-resistant RCC cells, and loss of MTHDF2 conferred sensitivity to sunitinib. In patients, MTHFD2 was highly expressed in RCC and was associated with poor outcomes. Mechanistically, MTHFD2 stimulated UDP-N-acetylglucosamine (UDP-GlcNAc) biosynthesis and promoted cMYC O-GlcNAcylation by driving the folate cycle. O-GlcNAcylation enhanced cMYC stability and promoted MTHFD2 and cyclin D1 transcription. Targeting MTHFD2 or cyclin D1 sensitized tumor cells to sunitinib in vitro and in vivo. Consistently, development of a peptide drug capable of efficiently degrading MTHFD2 enabled reversal of sunitinib resistance in RCC. These findings identify a noncanonical metabolic function of MTHFD2 in cell signaling and response to therapy and reveal the interplay between one-carbon metabolism and sunitinib resistance in RCC. Targeting MTHFD2 could be an effective approach to overcome sunitinib resistance. Significance: MTHFD2 regulates cMYC O-GlcNAcylation to promote sunitinib resistance in renal cell carcinoma, highlighting the important role of one-carbon metabolism in sunitinib resistance and proposing therapeutic strategies to improve patient outcomes.