Susceptibility to intestinal tumorigenesis in folate-deficient mice may be influenced by variation in one-carbon metabolism and DNA repair

Erin Knock, Liyuan Deng, Natalia Krupenko, Ryan D. Mohan, Qing Wu, Daniel Leclerc, Sapna Gupta, C. Lee Elmore, Warren Kruger, Marc Tini, Rima Rozen

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Low dietary folate is associated with increased risk of colorectal cancer. In earlier work, we showed that folate deficiency induced intestinal tumors in BALB/c but not C57Bl/6 mice through increased dUTP incorporation into DNA with consequent DNA damage. To determine whether strain differences between one-carbon metabolism and DNA repair pathways could contribute to increased tumorigenesis in BALB/c mice, we measured amino acids and folate in the normal intestinal tissue of both strains fed a control diet or a folate-deficient diet. We also determined the expression of critical folate-metabolizing enzymes and several DNA repair enzymes. BALB/c mice had lower intestinal serine (major cellular one-carbon donor), methionine and total folate than C57Bl/6 mice under both dietary conditions. BALB/c mice had higher messenger RNA and protein levels of three folate-interconverting enzymes: trifunctional methyleneTHF (5,10-methylenetetrahydrofolate) dehydrogenase-methenylTHF cyclohydrolase-formylTHF (10-formyltetrahydrofolate) synthetase 1, bifunctional methyleneTHF dehydrogenase-methenylTHF cyclohydrolase and methylenetetrahydrofolate reductase. This pattern of expression could limit the availability of methyleneTHF for conversion of dUMP to dTMP. BALB/c mice also had higher levels of uracil DNA glycosylase 2 protein without an increase in the rate-limiting DNA polymerase β enzyme, compared with C57Bl/6 mice. We conclude that BALB/c mice may be more prone to DNA damage through decreased amounts of one-carbon donors and the diversion of methyleneTHF away from the conversion of dUMP to dTMP. In addition, incomplete excision repair of uracil in DNA could lead to accumulation of toxic repair intermediates and promotion of tumorigenesis in this tumor-susceptible strain.

Original languageEnglish
Pages (from-to)1022-1029
Number of pages8
JournalJournal of Nutritional Biochemistry
Volume22
Issue number11
DOIs
StatePublished - Nov 2011

Keywords

  • Aminohydrolases/metabolism
  • Animals
  • Colorectal Neoplasms/genetics
  • DNA Methylation
  • DNA Polymerase beta/metabolism
  • DNA Repair/genetics
  • Diet
  • Folic Acid Deficiency/complications
  • Folic Acid/metabolism
  • Formate-Tetrahydrofolate Ligase/metabolism
  • Methylenetetrahydrofolate Dehydrogenase (NADP)/metabolism
  • Methylenetetrahydrofolate Reductase (NADPH2)/genetics
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Multienzyme Complexes/metabolism
  • RNA, Messenger/metabolism
  • Serine/metabolism
  • Tetrahydrofolates/metabolism
  • Uracil-DNA Glycosidase/metabolism

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