N12003: Novel DNA biomarkers for folate deficiency in surrogate tissues and colonic mucosa
Wednesday 10 September 2003
This research project aims to identify biomarkers of folate deficiency and assess the effect of dietary folate supplementation on these.
Background
There is epidemiological evidence to link folate deficiency to colon cancer. We are developing assays for DNA replication-linked biomarkers for folate deficiency in colonic mucosa – gene-specific methylation, and uracil misincorporation – in an existing FSA contract. We here propose to extend these to more easily accessible surrogate tissues, neutrophils and buccal cells. To determine which sequences of the genome are most suitable as surrogates, we will screen large numbers of oncogenes and tumor suppressor genes for differential methylation and uracil misincorporation, using microarray technology; and validate these biomarker assays against both systematic and colonic folate status.
Research Approach
Colon biopsies will be obtained from subjects in St James Hospital, Dublin. Buccal cells will be obtained from these subjects, as part of the revised protocol for that project. Blood samples will also be obtained and granulocytes (which have a high rate of DNA turnover and are therefore suitable for these studies). After developing a methylation sensitive microarray technique, it will be applied to establish which genes, in surrogate tissue, correlate in their degree of undermethylation with genes in colonic tissue. A similar approach will be carried out looking at uracil misincorporation in surrogate and colonic tissue. These techniques will be used to assess the effect of folate supplementation, in both colonic and surrogate tissue, on methylation and uracil misincorporation in specific genes.