Does Zinc Fight Prostate Cancer?

Scientists have known for decades that zinc may play a role in maintaining the health of the prostate, the walnut-size gland in males, located just behind the bladder. Now, studies led by Agricultural Research Service (ARS) geneticist Liping Huang are providing new details about how zinc in the foods we eat might keep prostate cancer cells from proliferating and spreading.

Prostate cancer is the second most common cause of cancer-related death among American men.

Huang is based at the ARS Western Human Nutrition Research Center in Davis, Calif. She's investigating the roles of zinc-transporter proteins, which move zinc in and out of cells in tissue, such as that in the prostate.

In a series of laboratory experiments, Huang and colleagues compared levels of zinc and zinc-transporter proteins in certain cancerous and noncancerous human prostate cells known as epithelial cells. They exposed the cells to a solution of zinc, then found that the cancerous cells accumulated lower levels of zinc compared to the normal cells. That might be explained by another of the team's findings: The cancerous cells had lower levels of a zinc-transporter protein known as ZIP1.

Although another zinc-ferrying-protein, ZIP3, was present in the cancer cells, it wasn't in the correct location.

In all, the results suggest that reduced levels of one transporter protein, ZIP1, and mislocation of another, ZIP3, may play a role in prostate cancer's progression. These preliminary findings are the first to provide direct evidence of the difference in levels and locations of zinc-transporter proteins in healthy and cancerous prostate epithelial cells.

For the experiments, Huang used cells that had the same genetic background. Dissimilar genetic backgrounds could have skewed test results.

ARS, the U.S. Department of Agriculture's chief scientific research agency, and the National Institutes of Health of the U.S. Department of Health and Human Services, are funding the research. Read more about it in the June 2005 issue of Agricultural Research magazine.