Therapeutic targeting of Myc-reprogrammed cancer cell metabolism

Studies from many laboratories document that the MYC oncogene produces a pleiotropic transcription factor, Myc, which influences genes driven by all three RNA polymerases to orchestrate nutrient import with biomass accumulation for cell division. Myc has been shown to activate genes involved in glycolysis, glutaminolysis, and mitochondrial biogenesis to provide ATP and anabolic substrates for cell mass accumulation. Myc stimulates ribosome biogenesis and orchestrates the energetic demand for biomass accumulation through its regulation of glucose and glutamine import and metabolism. When normal cells are deprived of nutrients, endogenous MYC expression diminishes and cells withdraw from the cell cycle. However, ectopic MYC-driven cancer cells are locked in a state of deregulated biomass accumulation, which renders them addicted to glucose and glutamine. This addictive state can be exploited for cancer therapy, because nutrient deprivation kills Myc-driven cells and inhibition of the Myc targets, lactate dehydrogenase A or glutaminase, diminishes tumor xenograft growth in vivo.