Green tea has preventative value in breast cancer. - GreenMedInfo Summary
Green tea catechin extract in intervention of chronic breast cell carcinogenesis induced by environmental carcinogens.
Mol Carcinog. 2011 Aug 31. Epub 2011 Aug 31. PMID: 21882252
Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, The University of Tennessee, Knoxville, Tennessee; Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, Tennessee.
Sporadic breast cancers are mainly attributable to long-term exposure to environmental factors, via a multi-year, multi-step, and multi-path process of tumorigenesis involving cumulative genetic and epigenetic alterations in the chronic carcinogenesis of breast cells from a non-cancerous stage to precancerous and cancerous stages. Epidemiologic and experimental studies have suggested that green tea components may be used as preventive agents for breast cancer control. In our research, we have developed a cellular model that mimics breast cell carcinogenesis chronically induced by cumulative exposures to low doses of environmental carcinogens. In this study, we used our chronic carcinogenesis model as a target system to investigate the activity of green tea catechin extract (GTC) at non-cytotoxic levels in intervention of cellular carcinogenesis induced by cumulative exposures to pico-molar 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and benzo[a]pyrene (B[a]P). We identified that GTC, at a non-cytotoxic, physiologically achievable concentration of 2.5 µg/mL, was effective in suppressing NNK- and B[a]P-induced cellular carcinogenesis, as measured by reduction of the acquired cancer-associated properties of reduced dependence on growth factors, anchorage-independent growth, increased cell mobility, and acinar-conformational disruption. We alsodetected that intervention of carcinogen-induced elevation of reactive oxygen species (ROS), increase of cell proliferation, activation of the ERK pathway, DNA damage, and changes in gene expression may account for the mechanisms of GTC's preventive activity. Thus, GTC may be used in dietary and chemoprevention of breast cell carcinogenesis associated with long-term exposure to low doses of environmental carcinogens. © 2011 Wiley-Liss, Inc.