Vitamin D and the Epigenetic Machinery in Colon Cancer

Vitamin D is an important hormone that regulates many physiological processes related to human health. Through its nuclear receptor, VDR, vitamin D controls gene expression through genetic and epigenetic mechanisms. Increasing data have demonstrated the anti-cancer activities of vitamin D in various cancers, including colon cancer. This review summarizes the recent progresses in our understanding of the molecular mechanisms of vitamin D and its interaction with the epigenetic machinery in colon cancer. Vitamin D changes the status of DNA methylation and histone modifications, resulting in the activation of tumor suppressors and inhibition of oncogenes. In addition, vitamin D activates the expression of tumor suppressing miRNAs, which contribute to the tumor suppressive activity. Further understanding of the epigenetic action of vitamin D will help the development of therapeutic strategies targeting the vitamin D signaling pathway without inducing the hypercalcemic side effects.