Flavonoids May Inhibit Prostate Cancer

Previous studies have suggested that increased intake of flavonoids which are common in fruits and vegetables may be associated with a reduced risk of prostate cancer, according to Sanjay Gupta, Ph.D., an assistant professor in the Case School of Medicine Department of Urology. Apigenin is a plant flavonoid commonly found in fruits and vegetables, as well as herbs, including chamomile, lemon balm, perilla and parsley.

"Flavonoids have aroused considerable interest recently because of their potential beneficial effects on human health, and have reported to have antiviral, anti-allergic, antiplatelet, anti-inflammatory, antitumor and antioxidant activities," Gupta said. "Apigenin has been shown to lower inflammation and oxidative stress, and exerts growth inhibitory effects on cancer cells."

In the study, Gupta and his team orally fed apigenin to mice two weeks before implanting a prostate tumor, then continuing the feedings for eight weeks. In a second protocol, apigenin was fed to mice two weeks after tumor implantation.

The first protocol mimicked prevention regimens, while the second followed therapeutic regimens for cancer.

In both cases, the apigenin slowed tumor growth and did not appear to cause any adverse side effects such as weight gain or changes in diet, which is common in patients who undergo chemotherapy treatments.

Apigenin also resulted in a decrease in IGF-1 (insulin-like growth factor) levels, which are associated with an increased risk of breast, prostate, colorectal and lung cancers, as well as a significant increase in IGFBP-3 (insulin-like growth factor binding protein) levels, which is associated with a decreased risk for these same cancers. The effect impacts the survival of prostate cancer by triggering cell self-destruction.

"Apigenin may prove useful in the prevention and therapy of prostate cancer by shutting off the IGF signaling that leads to prostate cancer cell growth and/or development," Gupta said.

"Our findings suggest that apigenin could be developed as a promising agent against prostate cancer," Gupta said. "The next step is to evaluate apigenin action on other molecular pathways which have relevance to prostate cancer."

Gupta's colleagues contributing to the study included Sanjeev Shukla, Ph.D.; Gregory T. MacLennan, M.D.; Pingfu Fu, Ph.D.; Martin I. Resnick, M.D.; from Case Western Reserve University and University Hospitals of Cleveland, and Anil Mishra, Ph.D. from University of Pittsburgh.