title: Inhibition of Nicotinamide Phosphoribosyltransferase (NAMPT), an Enzyme Essential for NAD+ Biosynthesis, Leads to Altered Carbohydrate Metabolism in Cancer Cells.
abstract: Nicotinamide phosphoribosyltransferase (NAMPT) has been extensively studied due to its essential role in NAD(+) biosynthesis in cancer cells and the prospect of developing novel therapeutics. To understand how NAMPT regulates cellular metabolism, we have shown that the treatment with FK866, a specific NAMPT inhibitor, leads to attenuation of glycolysis by blocking the glyceraldehyde 3-phosphate dehydrogenase step (Tan, B., Young, D. A., Lu, Z. H., Wang, T., Meier, T. I., Shepard, R. L., Roth, K., Zhai, Y., Huss, K., Kuo, M. S., Gillig, J., Parthasarathy, S., Burkholder, T. P., Smith, M. C., Geeganage, S., and Zhao, G. (2013) Pharmacological inhibition of nicotinamide phosphoribosyltransferase (NAMPT), an enzyme essential for NAD(+) biosynthesis, in human cancer cells: metabolic basis and potential clinical implications. J. Biol. Chem. 288, 3500-3511). Due to technical limitations, we failed to separate isotopomers of phosphorylated sugars. In this study, we developed an enabling LC-MS methodology. Using this, we confirmed the previous findings and also showed that NAMPT inhibition led to accumulation of fructose 1-phosphate and sedoheptulose 1-phosphate but not glucose 6-phosphate, fructose 6-phosphate, and sedoheptulose 7-phosphate as previously thought. To investigate the metabolic basis of the metabolite formation, we carried out biochemical and cellular studies and established the following. First, glucose-labeling studies indicated that fructose 1-phosphate was derived from dihydroxyacetone phosphate and glyceraldehyde, and sedoheptulose 1-phosphate was derived from dihydroxyacetone phosphate and erythrose via an aldolase reaction. Second, biochemical studies showed that aldolase indeed catalyzed these reactions. Third, glyceraldehyde- and erythrose-labeling studies showed increased incorporation of corresponding labels into fructose 1-phosphate and sedoheptulose 1-phosphate in FK866-treated cells. Fourth, NAMPT inhibition led to increased glyceraldehyde and erythrose levels in the cell. Finally, glucose-labeling studies showed accumulated fructose 1,6-bisphosphate in FK866-treated cells mainly derived from dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. Taken together, this study shows that NAMPT inhibition leads to attenuation of glycolysis, resulting in further perturbation of carbohydrate metabolism in cancer cells. The potential clinical implications of these findings are also discussed.
authors.affiliation: Discovery Chemistry, Lilly Research Laboratories, Eli Lilly and Co., Indianapolis, Indiana 46285.
authors.forename: Bo
authors.initials: B
authors.lastname: Tan
authors.affiliation: Cancer Research, Lilly Research Laboratories, Eli Lilly and Co., Indianapolis, Indiana 46285.
authors.forename: Sucai
authors.initials: S
authors.lastname: Dong
authors.affiliation: Cancer Research, Lilly Research Laboratories, Eli Lilly and Co., Indianapolis, Indiana 46285.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Shepard
authors.affiliation: Cancer Research, Lilly Research Laboratories, Eli Lilly and Co., Indianapolis, Indiana 46285.
authors.forename: Lisa
authors.initials: L
authors.lastname: Kays
authors.affiliation: Discovery Chemistry, Lilly Research Laboratories, Eli Lilly and Co., Indianapolis, Indiana 46285.
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Roth
authors.affiliation: Cancer Research, Lilly Research Laboratories, Eli Lilly and Co., Indianapolis, Indiana 46285.
authors.forename: Sandaruwan
authors.initials: S
authors.lastname: Geeganage
authors.affiliation: Discovery Chemistry, Lilly Research Laboratories, Eli Lilly and Co., Indianapolis, Indiana 46285. Electronic address: Kuo_Ming-Shang@Lilly.com.
authors.forename: Ming-Shang
authors.initials: MS
authors.lastname: Kuo
authors.affiliation: Cancer Research, Lilly Research Laboratories, Eli Lilly and Co., Indianapolis, Indiana 46285. Electronic address: Zhao_Genshi@Lilly.com.
authors.forename: Genshi
authors.initials: G
authors.lastname: Zhao
mesh_terms: D000178:Acrylamides / Q000494:pharmacology; D050260:Carbohydrate Metabolism; D016207:Cytokines / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D013058:Mass Spectrometry; D009243:NAD / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D054409:Nicotinamide Phosphoribosyltransferase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010880:Piperidines / Q000494:pharmacology; D013403:Sugar Phosphates / Q000235:genetics / Q000378:metabolism*
chemical_list: D000178:Acrylamides; D016207:Cytokines; D004791:Enzyme Inhibitors; C480543:N-(4-(1-benzoylpiperidin-4-yl)butyl)-3-(pyridin-3-yl)acrylamide; D009363:Neoplasm Proteins; D010880:Piperidines; D013403:Sugar Phosphates; D009243:NAD; D054409:Nicotinamide Phosphoribosyltransferase; C085455:nicotinamide phosphoribosyltransferase, human
keywords: carbohydrate metabolism; glucose metabolism; glycolysis; nicotinamide adenine dinucleotide (NAD); pharmacology