title: Ageing, chronic alcohol consumption and folate are determinants of genomic DNA methylation, p16 promoter methylation and the expression of p16 in the mouse colon.
abstract: Older age, dietary folate and chronic alcohol consumption are important risk factors for the development of colon cancer. The present study examined the effects of ageing, folate and alcohol on genomic and p16-specific DNA methylation, and p16 expression in the murine colon. Old (aged 18 months; n 70) and young (aged 4 months; n 70) male C57BL/6 mice were pair-fed either a Lieber-DeCarli liquid diet with alcohol (18 % of energy), a Lieber-DeCarli diet with alcohol (18 %) and reduced folate (0.25 mg folate/l) or an isoenergetic control diet (0.5 mg folate/l) for 5 or 10 weeks. Genomic DNA methylation, p16 promoter methylation and p16 gene expression were analysed by liquid chromatography-MS, methylation-specific PCR and real-time RT-PCR, respectively. Genomic DNA methylation was lower in the colon of old mice compared with young mice (P < 0.02) at 10 weeks. Alcohol consumption did not alter genomic DNA methylation in the old mouse colon, whereas it tended to decrease genomic DNA methylation in young mice (P = 0.08). p16 Promoter methylation and expression were higher in the old mouse colon compared with the corresponding young groups. There was a positive correlation between p16 promoter methylation and p16 expression in the old mouse colon (P < 0.02). In young mice the combination of alcohol and reduced dietary folate led to significantly decreased p16 expression compared with the control group (P < 0.02). In conclusion, ageing and chronic alcohol consumption alter genomic DNA methylation, p16 promoter methylation and p16 gene expression in the mouse colon, and dietary folate availability can further modify the relationship with alcohol in the young mouse.
authors.affiliation: Vitamins and Carcinogenesis Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA.
authors.forename: Julia
authors.initials: J
authors.lastname: Sauer
authors.forename: Hyeran
authors.initials: H
authors.lastname: Jang
authors.forename: Ella M
authors.initials: EM
authors.lastname: Zimmerly
authors.forename: Kyong-Chol
authors.initials: KC
authors.lastname: Kim
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Liu
authors.forename: Aurelie
authors.initials: A
authors.lastname: Chanson
authors.forename: Donald E
authors.initials: DE
authors.lastname: Smith
authors.forename: Joel B
authors.initials: JB
authors.lastname: Mason
authors.forename: Simonetta
authors.initials: S
authors.lastname: Friso
authors.forename: Sang-Woon
authors.initials: SW
authors.lastname: Choi
mesh_terms: D000367:Age Factors; D000375:Aging / Q000235:genetics* / Q000378:metabolism; D000428:Alcohol Drinking; D000818:Animals; D018899:CpG Islands / Q000187:drug effects; D004247:DNA / Q000378:metabolism*; D019175:DNA Methylation; D005494:Folic Acid Deficiency / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D019942:Genes, p16; D016678:Genome; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic
chemical_list: D004247:DNA