Grape Seed Extract Suppresses Estrogen in Breast Cancer
Results may lead to new therapies that target estrogen Contact: Shawn Le 800-888-5323 sle@coh.org DUARTE, Calif., June 1, 2006--Scientists at City of Hope have discovered that chemicals in grape seed extract (GSE) in the form of skin, seeds and even red wine, can suppress the production of estrogen, a major player in the development of breast cancer. GSE can also act specifically upon cancerous breast tissue alone, which produces excess amounts of estrogen, without inhibiting critical estrogen production from healthy tissue. The findings could eventually lead to a preventative therapy that would help both pre- and post-menopausal women. The research, by Shiuan Chen, Ph.D., director and professor, Department of Surgical Research, Ikuko Kijima, a fourth year graduate student at City of Hope’s Graduate School of Biological Sciences, and colleagues, is reported in the June issue of the journal Cancer Research. It follows earlier work by Chen that showed GSE can inhibit the activity of estrogen. With the exception of non-melanoma skin cancers, breast cancer is the most common cancer among women. Approximately 70 percent of all breast cancers are estrogen driven. For years, researchers have targeted aromatase, an enzyme that converts androgen to the female hormone estrogen. While aromatase is normally expressed in a number of tissues such as ovary, placenta, fat and bone, aromatase is expressed at higher levels in breast cancer tissue than normal breast tissue. In the December 2003 Cancer Research, Chen’s lab identified a chemical compound purified from red wine called procyanidin dimers. It proved to be a powerful inhibitor of aromatase activity and also reduced tumor growth in a mouse model. Now the researchers have gone a step further and have shown that GSE can stop breast cancer cells from making the aromatase protein. “We have demonstrated that grape seed extract can have a dual effect,” said Chen. “It can suppress aromatase activity, as well as its expression.” Importantly, the researchers’ work demonstrates this suppression may be targeted to cancerous tissue. This is key to developing future preventative treatment, particularly for pre-menopausal women. While aromatase inhibitors are very effective in suppressing estrogen formation, patients have also experienced side effects associated with estrogen deficiency, such as bone loss. That is because current aromatase inhibitors suppress estrogen in the whole body. The goal of researchers like Chen is to design treatment strategies that selectively suppress aromatase expression in breast tumor tissue while maintaining estrogen levels in normal tissues. The discovery by Kijima, Chen and colleagues that GSE does indeed suppress aromatase expression in breast tumors suggests there are chemicals (not necessarily procyanidin dimers) in GSE that do this, and thus may ultimately be developed as a cancer therapeutic. “We believe these are exciting results because they demonstrate that GSE may be potentially useful in both the treatment as well as the prevention of hormone-dependent breast cancer,” said Chen. Chen said his lab’s ongoing work is to identify the chemicals in GSE that are involved in suppressing estrogen, develop therapeutic drugs based on these chemicals, and eventually go to clinical trials for pre-menopausal women. About City of Hope City of Hope is a leading research and treatment center for cancer, diabetes and other life-threatening diseases. Designated as a Comprehensive Cancer Center, the highest honor bestowed by the National Cancer Institute, and a founding member of the National Comprehensive Cancer Network, City of Hope’s research and treatment protocols impact care throughout the nation. Founded in 1913, City of Hope is a pioneer in the fields of bone marrow transplantation and genetics and shares its scientific knowledge with medical centers locally and globally, helping patients battling serious diseases. For more information, visit www.cityofhope.org.