OHSU

Can Herbal Supplements Prevent Prostate Cancer?

Prostate cancer is the number two killer of men in the U.S., just behind lung cancer. One man in six will get prostate cancer in his lifetime and for one man in 33, this will be the cause of his death. There is currently no cure for metastatic prostate cancer. However, prostate cancer is typically a disease of elderly men so that pharmacological or nutritional interventions that cause even a modest delay in its development could result in a substantial reduction in its prevalence and improvement in quality of life. Surveys show that the use of dietary supplements is highly prevalent in men with prostate cancer, but there is no rigorous scientific information about their effectiveness and mechanisms of action. This is due in part to the fact that dietary supplements do not require FDA approval. Saw palmetto (Serenoa repens) is a palm native to the southeastern U.S. Extracts made from its berry are used to treat urinary symptoms associated with prostate disease and are self-prescribed by millions of men to promote prostate health. My lab has been investigating saw palmetto berry extract for its ability to prevent the progression of prostate cancer in a transgenic mouse model (TRAMP) that closely mimics the stages of human prostate cancer. The research also involves a cell culture approach aimed at dissecting the important cellular pathways in prostate cancer cells that are affected by saw palmetto extract complemented by animal studies to determine whether these same pathways are altered in vivo. Understanding the pleiotrophic effects of this natural product could provide effective strategies for a dietary approach to prostate cancer prevention.

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Figure: Progression of prostate pathology in TRAMP mice
A, normal; B, prostate interepithelial neoplasia (PIN); C, well-differentiated cancer; D, poorly differentiated cancer.

 

pathology_tumor-incidence-chart

We recently demonstrated that oral administation of saw palmetto to TRAMP mice increases apoptosis, and reduce tumor grade and frank tumor incidence. These results support the idea that dietary supplementation with saw palmetto extract could be effective in preventing or delaying the onset and progression of prostate cancer. Further studies are planned to elucidate the active components of SPE, determine whether SPE improves survival in TRAMP mice, and evaluate the mechanim of saw palmetto's chemopreventive actions.