title: Bonded Cumomer Analysis of Human Melanoma Metabolism Monitored by 13C NMR Spectroscopy of Perfused Tumor Cells.
abstract: A network model for the determination of tumor metabolic fluxes from (13)C NMR kinetic isotopomer data has been developed and validated with perfused human DB-1 melanoma cells carrying the BRAF V600E mutation, which promotes oxidative metabolism. The model generated in the bonded cumomer formalism describes key pathways of tumor intermediary metabolism and yields dynamic curves for positional isotopic enrichment and spin-spin multiplets. Cells attached to microcarrier beads were perfused with 26 mm [1,6-(13)C2]glucose under normoxic conditions at 37 °C and monitored by (13)C NMR spectroscopy. Excellent agreement between model-predicted and experimentally measured values of the rates of oxygen and glucose consumption, lactate production, and glutamate pool size validated the model. ATP production by glycolytic and oxidative metabolism were compared under hyperglycemic normoxic conditions; 51% of the energy came from oxidative phosphorylation and 49% came from glycolysis. Even though the rate of glutamine uptake was ∼ 50% of the tricarboxylic acid cycle flux, the rate of ATP production from glutamine was essentially zero (no glutaminolysis). De novo fatty acid production was ∼ 6% of the tricarboxylic acid cycle flux. The oxidative pentose phosphate pathway flux was 3.6% of glycolysis, and three non-oxidative pentose phosphate pathway exchange fluxes were calculated. Mass spectrometry was then used to compare fluxes through various pathways under hyperglycemic (26 mm) and euglycemic (5 mm) conditions. Under euglycemic conditions glutamine uptake doubled, but ATP production from glutamine did not significantly change. A new parameter measuring the Warburg effect (the ratio of lactate production flux to pyruvate influx through the mitochondrial pyruvate carrier) was calculated to be 21, close to upper limit of oxidative metabolism.
authors.affiliation: From the Department of Radiology, Laboratory of Molecular Imaging, ashestov@mail.med.upenn.edu.
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Shestov
authors.affiliation: Department of Radiology and Abramson Comprehensive Cancer Center, and.
authors.forename: Anthony
authors.initials: A
authors.lastname: Mancuso
authors.affiliation: From the Department of Radiology, Laboratory of Molecular Imaging.
authors.forename: Seung-Cheol
authors.initials: SC
authors.lastname: Lee
authors.affiliation: Systems Pharmacology, Perelman School of Medicine, Philadelphia, Pennsylvania 19104.
authors.forename: Lili
authors.initials: L
authors.lastname: Guo
authors.affiliation: From the Department of Radiology, Laboratory of Molecular Imaging.
authors.forename: David S
authors.initials: DS
authors.lastname: Nelson
authors.affiliation: From the Department of Radiology, Laboratory of Molecular Imaging.
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Roman
authors.affiliation: the Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, and.
authors.forename: Pierre-Gilles
authors.initials: PG
authors.lastname: Henry
authors.affiliation: the Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
authors.forename: Dennis B
authors.initials: DB
authors.lastname: Leeper
authors.affiliation: Systems Pharmacology, Perelman School of Medicine, Philadelphia, Pennsylvania 19104.
authors.forename: Ian A
authors.initials: IA
authors.lastname: Blair
authors.affiliation: From the Department of Radiology, Laboratory of Molecular Imaging, Departments of Biochemistry and Biophysics and glickson@mail.med.upenn.edu.
authors.forename: Jerry D
authors.initials: JD
authors.lastname: Glickson
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D066241:Carbon-13 Magnetic Resonance Spectroscopy; D045744:Cell Line, Tumor; D002952:Citric Acid Cycle; D005947:Glucose / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D006801:Humans; D008545:Melanoma / Q000378:metabolism*; D008962:Models, Theoretical; D020125:Mutation, Missense; D010085:Oxidative Phosphorylation; D010100:Oxygen / Q000378:metabolism; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics
chemical_list: D005973:Glutamine; D000255:Adenosine Triphosphate; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D005947:Glucose; D010100:Oxygen
keywords: bioenergy; cancer biology; glucose metabolism; glutaminase; isotopic tracer; mathematical modeling; metabolism; mitochondrial metabolism; nuclear magnetic resonance (NMR); transport