Anticancer Activity of Green Tea Polyphenols in Prostate Gland
Figure 2
Mechanisms of inhibition of DNMTs by GTCs. (a) In a cancer environment, specific genes are silenced by hypermethylation of their promoters. DNA hypermethylation is catalysed by DNMTs, which use as a substrate SAM and release SAH as a by-product. (b) Within this context GTCs are able to inhibit DNMTs through three distinct mechanisms. (1) Direct inhibition. (2) GTCs are methylated by COMT, resulting in a depletion of SAM and accumulation of the DNMT inhibitor SAH. (3) Direct inhibition of DHFR, resulting in disruption of the folate cycle that influences negatively the levels of SAM. Inhibition of DNMTs ultimately results in DNA hypomethylation and re-expression of previously repressed genes.
