Use of a novel genetic mouse model to investigate the role of folate in colitis-associated colon cancer. Academic Article uri icon

abstract

  • Inflammatory bowel disease (IBD) patients are at high risk for developing folate deficiency and colon cancer. Since it is difficult to study the subtle global and gene-specific epigenetic mechanisms involved in folate-mediated tumor initiation and promotion, we have generated genetically modified mouse models by targeting the reduced folate carrier (RFC1) and folate-binding protein (Folbp1) genes. The transgenic mice were fed semi-purified diets for 8 weeks containing either normal (2 mg) or deficient (0.1 mg folate/kg diet) levels of folate. Compound heterozygous mice (Folbp1(+/-); RFC1(+/-)) fed an adequate folate diet exhibited a reduction in plasma folate concentrations compared to heterozygous (Folbp1(+/-)) and littermate wild-type mice (P<.05). In contrast, no differences were observed in colonic mucosa. Consumption of a low folate diet significantly reduced (three- to fourfold) plasma and tissue folate levels in all animal models, although plasma homocysteine levels were not altered. In order to elucidate the relationship between folate status and inflammation-associated colon cancer, animals were injected with azoxymethane followed by dextran sodium sulphate treatment in the drinking water. Mice were fed a normal folate diet and were terminated 5 weeks after carcinogen injection. The number of high multiplicity aberrant crypt foci per centimeter of colon was significantly elevated (P<.05) in compound Folbp1(+/-); RFC1(+/-) (3.5+/-0.4) mice as compared to Folbp1(+/-) (1.9+/-0.3) and wild-type control mice (1.1+/-0.1). These data demonstrate that the ablation of two receptor/carrier-mediated pathways for folate transport increases the risk for developing inflammation-associated colon cancer.

published proceedings

  • J Nutr Biochem

author list (cited authors)

  • Chapkin, R. S., Kamen, B. A., Callaway, E. S., Davidson, L. A., George, N. I., Wang, N., Lupton, J. R., & Finnell, R. H.

citation count

  • 20

complete list of authors

  • Chapkin, Robert S||Kamen, Barton A||Callaway, Evelyn S||Davidson, Laurie A||George, Nysia I||Wang, Naisyin||Lupton, Joanne R||Finnell, Richard H

publication date

  • August 2009