Epigenetic modulation from epigallocatechin gallate, the major polyphenol found in green tea, in MCF-7 breast cancer cells.

A93

The consumption of tea has been linked to a lower incidence of cancer for some time. Green tea, one of the world's most popular beverages, has recently been the focus of much research; however the mechanisms of its anti-cancer effects are unknown. Epigallocatechin-3-gallate (EGCG) is the major polyphenol found in green tea and has been shown to alter the activity of DNA methyltransferases I, which is important in maintaining expression levels of methylation controlled genes. Telomerase is an important enzyme, adding telomeres to the ends of chromosomes allowing for cellular immortality. Its catalytic subunit (hTERT) is hypermethylated in MCF-7 breast cancer cells causing increased expression. In this study we have shown that EGCG causes de-methylation of the hTERT promoter leading to a decrease in expression and eventual apoptosis. In addition to the changes in methylation we have shown a decrease in histone acetylation which also leads to the gene's down-regulation. These data indicate that EGCG may work through an epigenetic mechanism in MCF-7 breast cancer cells. These results may help lead to an elucidation of the anti-cancer effects of polyphenols and facilitate their use in chemoprevention and therapeutics.