Possible Mechanism of Green Tea Inhibition of Breast Cancer Found.

A study conducted at the Uniformed Services University of the Bethesda National Naval Medical Center found that green tea has an anti-tumor effect in breast cancer cells and identified the potential mechanism. The study was published in the December 2007 Journal of Cancer Biology and Therapy.While there is no known therapy that is effective for estrogen independent breast cancer, epidemiological studies have shown that consumption of green tea polyphenols can reduce the incidence and progression of breast cancer. Green tea is an important source of polyphenols, principally Epigallocatechin gallate (EGCG), antioxidants that have been shown to be useful for chemoprevention through induction of apoptosis and inhibition of proliferation.This study evaluated the apoptotic and anti-invasive activity of green tea polyphenols and EGCG in MDA-MB-231 human breast cancer cell line. Using an in-vitro human breast cancer model, green tea polyphenols and EGCG were found to induce apoptosis and significantly decreased invasion of breast cancer cells. Fluorescent labeling revealed a 24-28% reduction in invasion through matrigel by EGCG and 15-23% reduction by green tea polyphenols in a dose dependent manner. Focused micro-array analysis and reverse transcriptase polymerase chain reaction and zymogram analysis revealed inhibition of Matrix metalloproteinase-9 expression by polyphenol treatment. Researchers identified modulation of betacatenin and AKT by green tea polyphenols and EGCG as a possible mechanism behind the induction of apoptosis and inhibition of invasive capacity of human breast cancer cells.