MTHFD2 links RNA methylation to metabolic reprogramming in renal cell carcinoma

One-carbon metabolism plays a central role in a broad array of metabolic processes required for the survival and growth of tumor cells. However, the molecular basis of how one-carbon metabolism may influence RNA methylation and tumorigenesis remains largely unknown. Here we show MTHFD2, a mitochondrial enzyme involved in one-carbon metabolism, contributes to the progression of renal cell carcinoma (RCC) via a novel epitranscriptomic mechanism that involves HIF-2 alpha. We found that expression of MTHFD2 was significantly elevated in human RCC tissues, and MTHFD2 knockdown strongly reduced xenograft tumor growth. Mechanistically, using an unbiased methylated RNA immunoprecipitation sequencing (meRIP-Seq) approach, we found that MTHFD2 plays a critical role in controlling global N-6-methyladenosine (m(6)A) methylation levels, including the m(6)A methylation of HIF-2 alpha mRNA, which results in enhanced translation of HIF-2 alpha. Enhanced HIF-2 alpha translation, in turn, promotes the aerobic glycolysis, linking one-carbon metabolism to HIF-2 alpha-dependent metabolic reprogramming through RNA methylation. Our findings also suggest that MTHFD2 and HIF-2 alpha form a positive feedforward loop in RCC, promoting metabolic reprograming and tumor growth. Taken together, our results suggest that MTHFD2 links RNA methylation status to the metabolic state of tumor cells in RCC.