Vitamin D inhibits progression of some prostate cancers

Vitamin D can inhibit the spread of prostate cancer cells by limiting the activity of two specific enzymes, University of Rochester Medical Center scientists report.

The finding means that vitamin D could provide beneficial treatment to prostate cancer patients with high levels of the enzymes, the scientists said.

"We wanted to know the targets of vitamin D so we would know which patients would respond better," said Yi-Fen Lee, Ph.D., an assistant professor of Urology at the Medical Center who led the research.

The journal Carcinogenesis published the findings by Lee and her fellow researchers in its January issue. The research was conducted in test tubes using human prostate cancer cells lines.

Research evidence increasingly has indicated that vitamin D suppresses the progression of cancer. Medical Center scientists discovered that vitamin D significantly limits the ability of prostate cancer cells to invade healthy cells by reducing the activity of two enzymes – proteases called matrix metalloproteinase and cathepsin. Vitamin D also increases the level of counterpart enzymes that inhibit matrix metalloproteinase and cathepsin, the Rochester scientists found.

Vitamin D, however, had little effect on plasminogen activators, which also are important in the spread of prostate cancer.

"Each individual is different so the therapy could be custom made for each person," Lee said.

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. But Lee and other scientists at the Medical Center's James P. Wilmot Cancer Center do not advise taking large amounts of vitamin D without medical supervision.

"This high dose has some side effects, including increasing blood calcium levels and causing kidney problems" said Edward M. Messing, M.D., chair of Urology at the Medical Center. "It should not be taken without prescription and a physician monitoring the side effects."

Lee is investigating whether there are medicines or other vitamins, such as vitamin E, that could enhance the anti-cancer effects of vitamin D without increasing toxicity.

"The best way to get vitamin D is to drink milk, get modest exposure to the sun, and take a vitamin pill to enrich the vitamin D, which might prevent cancer," Lee said.

In addition to Lee, authors of the Carcinogenesis article include Bo-Ying Bao, a University of Rochester graduate student, and Shauh-Der Yeh of the Department of Urology at Taipei Medical University.

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The research was supported by grants from the U.S. Department of Defense and the New York Academy of Medicine Edwin Beer Research Fund.

An estimated 232,000 new cases of prostate cancer were diagnosed in the United States last year – more than any other cancer in men. About 30,000 deaths occurred from prostate cancer in the United States last year.