Higher melatonin levels associated with lower risk of prostate cancer

Tuesday, January 21, 2014. The American Association for Cancer Research-Prostate Cancer Foundation Conference on Advances in Prostate Cancer Research, held January 18 to 21, 2014 in San Diego, was the site of a presentation by Sarah C. Markt, MPH, of Harvard School of Public Health's Department of Epidemiology, of the finding of a reduced risk of prostate cancer among men with higher levels of melatonin, a hormone known for its ability to induce sleep. Melatonin is released in response to darkness, and is involved in the regulation of the body's circadian rhythm.

The study included 928 men who were a part of the AGES-Reykjavik cohort in Iceland. Morning urinary samples were evaluated for 6-sulfatoxymelatonin at the beginning of the study in 2002 to 2006. Questionnaire responses provided information on sleep patterns and other factors.

Through 2009, 111 men developed prostate cancer, among whom 24 were diagnosed with advanced disease. Participants who reported sleep problems had lower melatonin levels than those who slept well. Among those whose urine melatonin levels were above the median of all subjects, there was a 31% lower risk of developing prostate cancer and a 75% lower risk of having advanced disease in comparison with men whose melatonin levels were below the median.

"Sleep loss and other factors can influence the amount of melatonin secretion or block it altogether, and health problems associated with low melatonin, disrupted sleep, and/or disruption of the circadian rhythm are broad, including a potential risk factor for cancer," Markt stated. "We found that men who had higher levels of melatonin had a 75 percent reduced risk for developing advanced prostate cancer compared with men who had lower levels of melatonin."

"Our results require replication, but support the public health implication of the importance of maintaining a stable light-dark and sleep-wake cycle," she added. "Because melatonin levels are potentially modifiable, further studies of melatonin and prostate cancer risk and progression are warranted."

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 Grapeseed compound demonstrates anticancer effect in prostate cancer cells

The journal Nutrition and Cancer published an article on November 5, 2013 in which researchers from the University of Colorado report an anticancer effect for a compound found in grape seed extract known as B2 3,3"-di-O-gallate (B2G2) in prostate cancer cells.

The research is the result of years of investigating grape seed's anticancer action. Working in the laboratory of Chapla Agarwal, PhD, of the University of Colorado Cancer Center, Alpna Tyagi, PhD and colleagues found that the administration of B2G2 isolated from grape seed extract as well as synthesized B2G2 resulted in cell growth inhibition, cell cycle arrest and apoptosis (programmed cell death) in several human prostate cancer cell lines. The compound was discovered to inhibit nuclear factor kappa-beta (NF-kB) transcriptional activity and other factors.

"We've shown similar anticancer activity in the past with grape seed extract, but now we know B2G2 is its most biologically active ingredient which can be synthesized in quantities that will allow us to study the detailed death mechanism in cancer cells," Dr Tyagi remarked. "Our goal all along has been a clinical trial of the biologically active compounds from grape seed extract against human cancer. But it's difficult to earn FDA approval for a trial in which we don't know the mechanisms and possible effects of all active components. Therefore, isolating and synthesizing B2G2 is an important step because now we have the ability to conduct more experiments with the pure compound. Ongoing work in the lab further increases our understanding of B2G2′s mechanism of action that will help for the preclinical and clinical studies in the future."

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