Effect of exposure to Epigallocatechin gallate‐3‐gallate and Epicatechin in the proliferation in the Breast Cancer cell line MDA‐MB 468

Abstract

Breast cancer is the most commonly diagnosed cancer in women, with more than 252,710 diagnosed in the United States each year. Diet is considered an important factor in breast cancer prevention and some studies suggest that green tea consumption has the potential to reduce breast cancer risk. Specifically catechins, a group of polyphenols that are found in plants, have been shown to have anti‐tumor effects such as promoting the decrease in tumor size and overall cancer growth. Many studies have investigated epigallocatechin‐3‐gallate (EGCG), one of the most abundant catechins in green tea, but less is known about the effect of epicatechin in breast cancer cell growth. Here, we investigated the inhibition of cell proliferation in the breast cancer cell lines, MDA‐MB 468 after exposure to varying concentrations of EGCG and epicatechin. Changes in proliferation were determined using the 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) assay after exposing cells for 24 and 48 hours to concentrations of catechins ranging from 1μM to 500μM. We found that after 24‐hr exposure, the cells significantly decreased in growth with a lower percent of cells remaining after exposure to 500μM EGCG. Percentage of cells was higher at 1μM when compared to 500μM (85.3 ± 1.9% vs. 44.0 ± 13.01% respectively (p=0.023)). However, when the cells were exposed to epicatechin in that same time period, there was no significant difference in proliferation between these concentrations (113.83 ± 17.87% vs. 87.94 ± 34.78% respectively (p=0.224)). Similar results were found at 48 hours. We found that as time increased from 24 to 48 hours, EGCG significantly inhibited the growth of cancer cells at 500μM (44.0 ± 13.01% vs. 8.58 ± 0.34%, respectively (p=0.031)). No effect was observed for epicatechin in growth as time increased. At an exposure of 500μM epicatechin, a higher percentage of cells were alive at 24 hours when compared to 48 hours but average values among experiments were not statistically significant (87.94 ± 34.78% vs. 40.47 ± 42.98%, respectively (p=0.174)). Our findings suggest that EGCG is a more potent inhibitor of triple negative breast cancer cell growth than epicatechin. Additional experiments at higher doses and longer exposures are needed to reach final conclusions, and we will be conducting those experiments next.