The study reveals the powers of two members of the chemical family known as polyphenols. The polyphenols don't block UV light, but they interfere with a cascade of chemical events, set off by UV light and other carcinogens, that lead to the uncontrolled cell division typical of cancer.
"We asked if polyphenols can block the process that turns a normal cell into a cancer cell," said Dong. "We looked for a target." The researchers studied the effects of polyphenols on "target" proteins known to be important in the chain of events leading to cancer. The proteins belonged to two classes: enzymes that activate other proteins, including other enzymes (protein kinases); and proteins that interact with DNA to influence the expression of genes (transcription factors).
The researchers shined UVB light, the ultraviolet light that causes skin cancer, on the shaven backs of mice. They also applied a substance called TPA, which promotes tumor formation. Mice in the experimental groups were swabbed with solutions containing polyphenols; mice in the control group received no further treatment. When the researchers measured activities of the protein kinases and transcription factors in the epidermis, they found that polyphenols inhibited both targets compared to epidermis from mice in the control group. Working with cultured human and mouse epid
Contact: Deane Morrison
University of Minnesota