When advanced Colon Cancer is not treated by Vitamin D – Mar 2012

Vitamin D resistance and colon cancer prevention

Charles Giardina charles.giardina@uconn.edu
James P. Madigan1,
Cassandra A. Godman Tierney,
Bruce M. Brenner1 and
Daniel W. Rosenberg1
Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, U3215, Storrs, CT 06269, USA
1 Center for Molecular Medicine, University of Connecticut Health Center, Farmington, CT 06030, USA
Received September 27, 2011; Revision received November 18, 2011; Accepted December 7, 2011.

Observational studies have been largely consistent in showing an inverse association between vitamin D and an individual’s risk of developing colorectal cancer.
Vitamin D protection is further supported by a range of preclinical colon cancer models, including carcinogen, genetic and dietary models.
A large number of mechanistic studies in both humans and rodents point to vitamin D preventing cancer by regulating cell proliferation.
Counterbalancing this mostly positive data are the results of human intervention studies in which supplemental vitamin D was found to be ineffective for reducing colon cancer risk.
One explanation for these discrepancies is the timing of vitamin D intervention.
It is possible that colon lesions may progress to a stage where they become unresponsive to vitamin D.
Such a somatic loss in vitamin D responsiveness bears the hallmarks of an epigenetic change.
Here, we review data supporting the chemopreventive effectiveness of vitamin D and discuss how gene silencing and other molecular changes somatically acquired during colon cancer development may limit the protection that may otherwise be afforded by vitamin D via dietary intervention.

Finally, we discuss how understanding the mechanisms by which vitamin D protection is lost might be used to devise strategies to enhance its chemopreventive actions.
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See also VitaminDWiki

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