University of Southern California researchers have found a gene that they are naming the “sunscreen gene”, which they believe helps protect people from getting skin cancer. The “UV radiation Resistance Associated Gene” works by suppressing tumors. Chengyu Liang, senior author of the study says that if we figure out how this UV-resistant gene functions and processes cell repair following ultraviolet damage, we may be able to find drug targets that can turn mechanisms back to their normal conditions.
The new study was published in Molecular Cell journal and states that over 90% of melanoma skin cancers develop because exposure to UV radiation causes cell damage. The American Cancer Society says melanoma kills over 10,000 people each year. Liang says people who have the mutated UV-resistant gene may be at a higher risk of developing skin cancers, especially if they spend a lot of time sunbathing or in tanning beds. The study suggests that the UV-resistant gene may be used as a biomarker for the prevention of skin cancer in the future.
Researchers used data from 340 melanoma patients, as well as two experimental groups that had either low levels of the UV-resistant gene, or a mutant copy of that gene in melanoma cells and 50 fly eyes. UV shots were given to the cells that carried the normal UV-resistant gene and cells that had the defective copies of the gene. 24 hours later, cells that contained normal versions of the gene had started to repair themselves by about 50%, while defective samples repaired about 20% of the damage. Liang explains the data saying it shows that individuals with defective UV-resistant genes are at a much higher risk of developing skin cancer because their bodies do not bounce back as effectively from cell damage after regular UV exposure.
The UV-resistant gene was discovered about two decades ago during studies of Xeroderma Pigmentosum. This defect makes people very sensitive to sunlight, with a high risk of skin cancer. Back then, the UV-resistant gene was not studied in healthy individuals or those who had skin cancer. Lead author and Keck Medicine of USC research associate says the UV-resistant gene is now known as a tumor suppressor that is involved in the UV-repair process of cell DNA. The gene is essential in the prevention of UV-induced genomic instability. If the gene is lost, the cell is not able to repaid UV or chemically-induced damage.
This resistant gene is part of the multistep cell-repair process of DNA which involves proteins scanning for damaged DNA. The protein places a “tag” on damaged locations, sending the UV-resistant gene to bring reinforcements, beginning the repairing process immediately. As of yet, researchers have not studied individuals who do not have skin cancer, so there are not yet comparisons between the two.
Yang says when there are lower levels of the UV-resistant gene, there is also a lower survival rate and advanced metastases stages. Redheads are also more prone to skin cancer than those with other hair colors because of their genetic differences. Liange says based on their current knowledge, the UV-resistant gene does not contain any enzymic activity, but works as a supporter or coordinator that is required for the healing process to take place at all.
Yang hopes one day this research can help to build a drug that can stimulate the UV-resistant gene to repair skin cells that have been damaged by UV exposure, serving as a great treatment solution for those who may be at a much higher risk of developing skin cancer at some point in their lives.