The combination of green tea and tamoxifen is effective against breast cancer

Epidemiologic data have suggested that green tea may prevent breast cancer. Studies in our laboratory have provided evidence that green tea extract inhibits breast cancer growth by a direct anti-proliferative effect on the tumor cells, as well as by indirect suppressive effects on the tumor-associat...

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Bibliographic Details
Published in:	Carcinogenesis (New York) Vol. 27; no. 12; pp. 2424 - 2433
Main Authors:	Sartippour, Maryam R., Pietras, Richard, Marquez-Garban, Diana C., Chen, Hsiao-Wang, Heber, David, Henning, Susanne M., Sartippour, Guilan, Zhang, Liping, Lu, Ming, Weinberg, Olga, Rao, Jian Yu, Brooks, Mai N.
Format:	Journal Article
Language:	English
Published:	Oxford Oxford University Press 01-12-2006 Oxford Publishing Limited (England)
Subjects:	Animals Apoptosis Beverages Biological and medical sciences Breast cancer Breast Neoplasms - drug therapy Breast Neoplasms - pathology Carcinogenesis, carcinogens and anticarcinogens Cell Division - drug effects Cell Line, Tumor Estrogen Receptor alpha - drug effects Estrogen Receptor alpha - metabolism Female Gynecology. Andrology. Obstetrics Humans Mammary gland diseases Medical sciences Mice Mice, Nude Mitogen-Activated Protein Kinase 1 - metabolism Mitogen-Activated Protein Kinase 3 - metabolism Plant Extracts - pharmacology Plant Extracts - therapeutic use Tamoxifen - pharmacology Tamoxifen - therapeutic use Transcription, Genetic - drug effects Transplantation, Heterologous Tumors Antineoplastic agent Mammary gland diseases Efficiency Antiestrogen Breast cancer Antihormone Malignant tumor Non steroid compound Green tea Tamoxifene
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Summary:	Epidemiologic data have suggested that green tea may prevent breast cancer. Studies in our laboratory have provided evidence that green tea extract inhibits breast cancer growth by a direct anti-proliferative effect on the tumor cells, as well as by indirect suppressive effects on the tumor-associated endothelial cells. In this study, we asked whether concurrent administration of green tea may add to the anti-tumor effects of standard breast cancer therapy. We observed that green tea increased the inhibitory effect of tamoxifen on the proliferation of the ER (estrogen receptor)-positive MCF-7, ZR75, T47D human breast cancer cells in vitro. This combination regimen was also more potent than either agent alone at increasing cell apoptosis. In animal experiments, mice treated with both green tea and tamoxifen had the smallest MCF-7 xenograft tumor size, and the highest levels of apoptosis in tumor tissue, as compared with either agent administered alone. Moreover, the suppression of angiogenesis in vivo correlated with larger areas of necrosis and lower tumor blood vessel density in treated xenografts. Green tea decreased levels of ER-α in tumors both in vitro and in vivo. We also observed that green tea blocked ER-dependent transcription, as well as estradiol-induced phosphorylation and nuclear localization of mitogen-activated protein kinase. To our knowledge, this study is the first to show the interaction of green tea with the ER pathway, as well as provide mechanistic evidence that the combination of green tea and tamoxifen is more potent than either agent alone in suppressing breast cancer growth. These results may lead to future improvements in breast cancer treatment and prevention.
Bibliography:	istex:8027CD26D1590C550A775A4FF3CD160AF3AF5BBD ark:/67375/HXZ-S25B4LVZ-9
ISSN:	0143-3334 1460-2180
DOI:	10.1093/carcin/bgl066