Changes in DNA methylation after 6-week exercise training in colorectal cancer survivors: A preliminary study.

Aim: Behavioral interventions such as exercise may induce epigenetic changes. Only few studies investigated the effects of exercise on epigenetic alterations in colorectal cancer survivors. The aim of this study was to explore the changes of genome-wide DNA methylation after 6-week exercise training in colorectal cancer survivors.

Methods: This preliminary study used a subset of data from a randomized controlled trial in 15 colorectal cancer survivors. Participants were randomized either to the 6-week exercise group or control group. The exercise intervention consisted of a weekly, group-based, supervised resistance exercise program and a home-based same resistance exercise plus walking six times per week. Blood samples were collected at baseline and after the intervention and data from eight subjects were analyzed for genome-wide DNA methylation on 865,918 CpG sites.

Results: Compared to the control group, the exercise group shows notable methylation changes in 756 CpG sites (22.7-25.2%). Gene ontology and disease annotation analysis showed that the genes targeting 81 CpG sites in promoter region with significant group-difference were linked in biological process such as immune response and transcription and related to metabolic and immune diseases. Also, hypermethylation on genes related to disease prevention seemed to be inhibited in the exercise group compared to the control group, indicating a likelihood of transcriptional activity of these genes.

Conclusion: We found a preliminary evidence of the positive effects of exercise intervention on epigenetic markers in colorectal cancer survivors. Larger scale randomized controlled trials are warranted to further investigate our findings.