Distinguished Professor of
Jerry Hendricks, Ph.D.
David Williams, Ph.D.
Our program has focused for the past 12 years on factors in the human diet that can prevent cancer in experimental animals. The goals are to understand the mechanisms through which these compounds operate and their potential application to reducing human cancer risk.
Though much of our work is done with traditional rodent species, most studies have been conducted with rainbow trout, a fish species with unique attributes as a cancer research model. For example, the fact that the trout is only distantly related to mammals allows us to identify aspects of the cancer process that are common to all vertebrates, and hence most likely to apply to cancer in humans. We now know that trout, mice, and humans all share proto-oncogene and tumor suppressor gene sequences, that mutations within these families of regulatory genes are fundamental to the process of cancer initiation and progress to malignancy, and that prevention of such mutations by dietary chemical components is one promising route to the reduction of cancer risk.
Trout are also far less costly than rats and mice, thus enabling us to design large-scale dose-response experiments in cancer prevention that are so statistically challenging as to be unaffordable, were rodent models to be used.
Hundreds of chemicals in the plants we eat have been shown to inhibit cancer in experimental animals. We have been particularly interested in three of these indole-3-carbinol (I3C) from the cabbage family, the chlorophylls (CHL) common to all green plants, and the hormone dehydroepiandrosterone (DHEA) from yams.
In animals, CHL has been found to block cancer initiation by binding very tightly to certain classes of carcinogens, reducing their uptake into the body, and increasing the amount of carcinogen excreted harmlessly from the body. Clinical trials are planned to see if CHL can reduce the risk of liver cancer in populations in China and Africa exposed to the liver carcinogen aflatoxin B1, and of colon cancer in this country caused by the heterocyclic amine carcinogens present in broiled meats.
I3C is a natural anti-estrogen of considerable promise in the battle against breast cancer. Current research in our laboratory seeks to understand if this promising activity more than offsets the harmful effects that I3C has shown in certain types of tumor studies. Similar research is being conducted with DHEA, which has elicited great interest as an anti-aging, anticancer magic bullet, but which also has enhanced liver cancer in rats and trout.
Our research has been funded by grants from the National Cancer Institute and from the National Institute of Environmental Health Sciences.
Last updated November, 1996
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