Gene-Based Sunscreen Might Someday Prevent Skin Cancer
Friday, December 7, 2007; 12:00 AM
FRIDAY, Dec. 7 (HealthDay News) -- Research is shedding new light on sunscreens that might someday prevent or treat skin cancer by reversing dangerous gene mutations caused by overexposure to the sun.
Working with hairless mice, researchers found that a synthetic compound called CP-31398 helped stabilize damage in the tumor-suppressing p53 gene. This type of damage occurs in humans and mice alike after sustained exposure to the sun's ultraviolet B (UVB) rays.
Once treated and repaired, the UVB-exposed p53 mouse gene resumed its normal cancer-preventing activity, inhibiting the spread and proliferation of tumor cells.
"Once the skin is exposed to UVB it leads to mutations in the p53 gene, and it becomes nonfunctional, and then you see induction of skin cancer " explained study lead author Mohammad Athar, a professor of dermatology at the University of Alabama, Birmingham.
"But this compound we used interacts with the p53 mutant genes and converts them back into functional genes," he said. "And that led to less incidence of skin cancer tumors, fewer numbers of tumors, and slower tumor growth in the UVB-exposed mice populations we tested."
Athar's findings are published in the December issue ofThe Journal of Clinical Investigation.
In all, the authors conducted four mouse experiments during which the animals were irradiated with UVB for periods of time ranging from 16 weeks to 40 weeks.
Some mice were given topical or injected versions of CP-31398, either immediately before a scheduled exposure to UVB, immediately following it, or for an extended period of weeks following discontinuation of all UVB exposure. For comparison purposes, other mice were not given CP-31398 at all.
CP-31398 seemed to prevent the onset of cancer altogether in UVB-exposed mice treated prior to the development of tumors, the team found.
As well, the compound appeared to limit the growth of skin tumors that had formed prior to the treatment's application.
In both cases, the observed success was attributed to the compound's ability to jumpstart proper p53 function, the researchers said.
Athar pointed out that p53 mutations linked to skin cancer are also present in more than half of all tumor types, so the current work could theoretically lead to cancer prevention applications for a range of diseases beyond melanoma.