title: c-Myc activates multiple metabolic networks to generate substrates for cell-cycle entry.
abstract: Cell proliferation requires the coordinated activity of cytosolic and mitochondrial metabolic pathways to provide ATP and building blocks for DNA, RNA and protein synthesis. Many metabolic pathway genes are targets of the c-myc oncogene and cell-cycle regulator. However, the contribution of c-Myc to the activation of cytosolic and mitochondrial metabolic networks during cell-cycle entry is unknown. Here, we report the metabolic fates of [U-(13)C] glucose in serum-stimulated myc(-/-) and myc(+/+) fibroblasts by (13)C isotopomer NMR analysis. We demonstrate that endogenous c-myc increased (13)C labeling of ribose sugars, purines and amino acids, indicating partitioning of glucose carbons into C1/folate and pentose phosphate pathways, and increased tricarboxylic acid cycle turnover at the expense of anaplerotic flux. Myc expression also increased global O-linked N-acetylglucosamine protein modification, and inhibition of hexosamine biosynthesis selectively reduced growth of Myc-expressing cells, suggesting its importance in Myc-induced proliferation. These data reveal a central organizing function for the Myc oncogene in the metabolism of cycling cells. The pervasive deregulation of this oncogene in human cancers may be explained by its function in directing metabolic networks required for cell proliferation.
authors.affiliation: Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
authors.forename: F
authors.initials: F
authors.lastname: Morrish
authors.forename: N
authors.initials: N
authors.lastname: Isern
authors.forename: M
authors.initials: M
authors.lastname: Sadilek
authors.forename: M
authors.initials: M
authors.lastname: Jeffrey
authors.forename: D M
authors.initials: DM
authors.lastname: Hockenbery
mesh_terms: D000117:Acetylglucosamine / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002247:Carbon Isotopes; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D002952:Citric Acid Cycle; D003470:Culture Media / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D006019:Glycolysis; D009682:Magnetic Resonance Spectroscopy; D053858:Metabolic Networks and Pathways / Q000235:genetics / Q000502:physiology*; D008928:Mitochondria / Q000378:metabolism; D009154:Mutation; D017351:N-Acetylglucosaminyltransferases / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D010767:Phosphorylcholine / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D012196:Review Literature as Topic; D053719:Tandem Mass Spectrometry
chemical_list: D002247:Carbon Isotopes; D003470:Culture Media; D016271:Proto-Oncogene Proteins c-myc; D010767:Phosphorylcholine; D018698:Glutamic Acid; D017351:N-Acetylglucosaminyltransferases; C449880:O-GlcNAc transferase; D005947:Glucose; D000117:Acetylglucosamine