Shiuan Chen, Ph.D. Chemoprevention Research Program

Since the summer of 2004, Dr. Chen and 27 other investigators have initiated an effort to develop a chemoprevention research program at City of Hope. Through biweekly meetings, these Beckman researchers and clinicians exchange research information and ideas. Four research areas have recently been chosen to focus on. The immediate goal is to generate preliminary results in these new target areas that will lead to the development of multidiscipline translational chemoprevention research projects at our institution.
Our laboratory has found that grapes, mushrooms and pomegranate contain chemicals that can suppress aromatase activity. Therefore, a diet that includes grapes, mushrooms and pomegranate would be considered preventative against breast cancer. We are purifying and characterizing these natural anti-aromatase chemicals and evaluating their in vivo effects using animal experiments. The active chemicals in grapes have been found to be procyanidin dimers that are present at high concentrations in grape seeds. Melanie Palomares, M.D., (Population Sciences), Jeffrey Weitzel, M.D., (Clinical Cancer Genetics), Tim Synold, Pharm.D., (Experimental Therapeutics) and this laboratory have collaborated and initiated a grape seed extract clinical trial and a mushroom clinical trial based on the chemoprevention studies against breast cancer performed in our laboratory.
Furthermore, we have found that mushrooms contain chemicals that act as inhibitors of steroid 5-alpha reductase. Androgen plays a critical role in prostate cancer development. In the prostate, testosterone (an androgen) is converted to dihydrotestosterone (DHT), an androgen that is even more potent than testosterone. This conversion is catalyzed by the enzyme steroid 5-alpha reductase. An elevation of the steroid 5-alpha reductase activity in the prostate may cause benign prostate hyperplasia (a common problem in older men) and also promote the growth of prostate cancer. Animal experiments have been performed to evaluate the use of these phytochemicals as drugs in the prevention and/or treatment of prostate cancer. One clinical trial designed, based Dr. Chen's findings, is being carried out at City of Hope with Przemyslaw Twardowski, M.D. (Medical Oncology). A recent study in the Chen laboratory has revealed that the intake of mushrooms may reduce the incidence of metabolic diseases such as fatty liver and insulin resistance.
In addition, experiments have been carried out to show that blueberry contains phytochemicals that can suppress the proliferation and migration of triple negative breast cancer in cell culture and animals. Efforts are being made to initiate a blueberry clinical trial at City of Hope.