By inducing a specific gene to increase expression of a key enzyme, vitamin D protects healthy prostate cells from the damage and injuries that can lead to cancer, University of Rochester Medical Center researchers report.

"Many epidemiological studies have suggested the beneficial properties of vitamin D," said Yi-Fen Lee, associate professor of urology and research leader. "Our findings reflect what we see in those studies and demonstrate that vitamin D not only can be used as a therapy for prostate cancer, it also can prevent prostate cancer from developing."

The International Journal of Cancer will publish the findings in its June 15 issue.

The vitamin D used in the study is 1, 25-hydroxylvitamin D3, the most potent and active form of vitamin D in the human body. Nonmalignant human prostate epithelial cells also were used.

Normal metabolism in cells generates reactive oxygen species (ROS), molecules of peroxide, for example, or so-called free radicals. These substances can play a role in cell signaling and even kill bacteria. Exposure to some chemicals or forms of radiation can produce high levels of ROS that can damage DNA and play a significant role in accelerating the aging process or causing cancer.

Lee found that vitamin D links with a gene known as G6PD, increasing its activity and the production of an enzyme called glucose-6-phosphate dehydrogenase. Increased activity of the enzyme clears cells of ROS, the molecules that can damage and injure cells.

The G6PD pathway is one of the mechanisms vitamin D uses, Lee says. However, the researchers did not find any similar activity in prostate cancer cells, which indicates that vitamin D does not protect cancer cells from injury or damage.

"If you reduce DNA damage, you reduce the risk of cancer or aging," Lee says, but adds that large amounts of vitamin D should not be taken without medical supervision.

In the journal Carcinogenesis in 2006, Lee reported that vitamin D can inhibit the spread of prostate cancer by limiting the ability of cancer cells to invade healthy cells by reducing the activity of two specific enzymes, proteases called matrix metalloproteinase and cathepsin. The research was conducted in test tubes using human prostate cancer cell lines. That finding indicated that vitamin D could provide beneficial treatment to prostate-cancer patients with high levels of the enzymes.

Source: ScienceDaily