By activating the enzyme protein kinase D, ultraviolet light helps nonmelanoma skin cancer cells survive and proliferate, researchers have found. The new research demonstrates that the effects of UV are cumulative and also dose-dependent, which means that more exposure to ultraviolet light leads to more protein kinase D activity. The enzyme isn’t all bad. Normally, protein kinase D helps regulate the replacement of cells that are continuously sloughed off. It enables skin cells to survive constant exposure to UV light. Dr. Wendy Bollag and Dr. Ismail Kaddour-Djebbar, a postdoctoral fellow and study co-author, have provided insight into how ultraviolet light causes nonmelanoma skin cancers, pointing the way toward better treatment. Courtesy of Phil Jones, MCG. But because it promotes cell survival, it can make badly damaged skin cells more likely to turn cancerous because it reduces their natural self-destruct ability, the researchers have shown. The team previously discovered that protein kinase D was upregulated in basal cell carcinoma. Sun exposure has been established as the most significant risk factor for basal cell carcinoma, so the researchers suspected that there was a link between ultraviolet radiation and protein kinase D. Pretreating skin cells with antioxidants, they now have found, appears to reduce protein kinase D activation by ultraviolet light; this could mean that free radicals also play a role. The research took place at the Medical College of Georgia and the Charlie Norwood Veterans Affairs Medical Center. The study was published in the journal Oncogene.