title: Vitamin D intake is negatively associated with promoter methylation of the Wnt antagonist gene DKK1 in a large group of colorectal cancer patients.
abstract: Diet and lifestyle influence colorectal cancer (CRC) risk but the molecular events that mediate these effects are poorly characterized. Several dietary and lifestyle factors can modulate DNA methylation suggesting that they may influence CRC risk through epigenetic regulation of cancer-related genes. The Wnt regulatory genes DKK1 and Wnt5a are important contributors to colonic carcinogenesis and are often silenced by promoter hypermethylation in CRC; however, the dietary contributions to these events have not been explored. To investigate the link between dietary/lifestyle factors and epigenetic regulation of these Wnt signaling genes, we assessed promoter methylation of these genes in a large cohort of Canadian CRC patients from Ontario (n = 549) and Newfoundland (n = 443) and examined associations to dietary/lifestyle factors implicated in CRC risk and/or DNA methylation including intake of vitamins, fats, cholesterol, fiber, and alcohol as well as body mass index (BMI), and smoking status. Several factors were associated with methylation status including alcohol intake, BMI, and cigarette smoking. Most significantly, however, dietary vitamin D intake was strongly negatively associated with DKK1 methylation in Newfoundland (P = 0.001) and a similar trend was observed in Ontario. These results suggest that vitamin D and other dietary/lifestyle factors may alter CRC risk by mediating extracellular Wnt inhibition.
authors.affiliation: Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.
authors.forename: James B
authors.initials: JB
authors.lastname: Rawson
authors.forename: Zhouyu
authors.initials: Z
authors.lastname: Sun
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Dicks
authors.forename: Darshana
authors.initials: D
authors.lastname: Daftary
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Parfrey
authors.forename: Roger C
authors.initials: RC
authors.lastname: Green
authors.forename: Steven
authors.initials: S
authors.lastname: Gallinger
authors.forename: John R
authors.initials: JR
authors.lastname: McLaughlin
authors.forename: Peizhong P
authors.initials: PP
authors.lastname: Wang
authors.forename: Julia A
authors.initials: JA
authors.lastname: Knight
authors.forename: Bharati
authors.initials: B
authors.lastname: Bapat
mesh_terms: D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects; D015992:Body Mass Index; D015179:Colorectal Neoplasms / Q000235:genetics*; D019175:DNA Methylation; D004041:Dietary Fats / Q000008:administration & dosage; D004043:Dietary Fiber / Q000008:administration & dosage; D044127:Epigenesis, Genetic; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008019:Life Style; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009523:Newfoundland and Labrador; D009864:Ontario; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results; D012907:Smoking / Q000009:adverse effects; D014807:Vitamin D / Q000008:administration & dosage*; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism; D060449:Wnt Signaling Pathway; D000071818:Wnt-5a Protein; D055815:Young Adult
chemical_list: C501126:DKK1 protein, human; D004041:Dietary Fats; D004043:Dietary Fiber; D036341:Intercellular Signaling Peptides and Proteins; D011518:Proto-Oncogene Proteins; C085389:WNT5A protein, human; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; D014807:Vitamin D