CREAM That Could Repair Sun Damage

SOUTH BEND, Ind. (AP) _ Researchers at the University of Notre Dame have produced an artificial enzyme they hope might some day prevent skin cancer from developing in millions of people.

The researchers hope the enzyme will reverse damage to DNA caused by overexposure to the sun. If it works, people whose skin was damaged years ago by sunburn or over-exposure to the sun would be able to use a cream that would repair the skin before cancer develops.

Such a cream, though, is years away, said Olaf Wiest, an assistant professor of chemistry at Notre Dame who heads the research team.

``I don't want to get people's hopes up too high because this is really basic research,'' Wiest said. ``I don't want people to get too hopeful because we don't really know if it will work.''

Typically, people's skin is damaged while they are in their teens or 20s, but the skin cancer doesn't develop until their 60s, Wiest said. The American Cancer Society estimates that about 1.3 million people will develop skin cancer this year and nearly 10,000 people die from it.

The enzyme developed by the Notre Dame researchers mimics an enzyme that the possum, E. coli bacteria and yeast all have that repairs their DNA when damaged by the sun's ultraviolet rays. The enzyme repairs thymine damage in the DNA.

Thymine is one of the four base molecules of DNA. When damaged by the sun, thymine proteins fuse together. The Notre Dame researchers hope their enzyme will repair the thymine.

They have been successful so far in getting the enzyme to work on thymine. The question now is whether it will work on a bigger section of DNA by locating the damaged area and repairing it. If that works, researchers will then need to see if it works on a skin cell and eventually on people.

The answer is years away and must eventually include biology scientists and a drug company with the financial backing to make it work, Wiest said. It's a longshot that this research will lead directly to a drug that will eventually be sold to consumers, but Wiest hopes it can help in the search for a solution.

``We won't eliminate all skin cancer, but if we could prevent, say, 90 percent of it, that would be amazing,'' Wiest said.

The researchers presented their finding in April to the American Chemical Society at their annual national meeting in San Diego.

Dr. Martin A. Weinstock, chairman of the American Cancer Society's skin cancer advisory board and professor of dermatology at Brown University, said Notre Dame's research is interesting.

``It's certainly worth pursuing. It's a promising avenue,'' he said. ``But there's a long way between that and actually reversing the damage in humans and seeing if reversing it in humans, if it makes a difference.''

Weinstock said there are scientists throughout the country trying to find ways to repair DNA damage cause by the sun.

``There are a lot of people pursuing the idea of addressing the skin cancer problem by looking at the molecular mechanism and interrupting that sequence of events that lead to skin cancer.''