Title: Dietary chromium and nickel enhance UV-carcinogenesis in skin of hairless mice.
Authors: Uddin, Ahmed N; Burns, Fredric J; Rossman, Toby G; Chen, Haobin; Kluz, Thomas; Costa, Max
Published In Toxicol Appl Pharmacol, (2007 Jun 15)
Abstract: The skin cancer enhancing effect of chromium (in male mice) and nickel in UVR-irradiated female Skh1 mice was investigated. The dietary vitamin E and selenomethionine were tested for prevention of chromium-enhanced skin carcinogenesis. The mice were exposed to UVR (1.0 kJ/m(2) 3 x weekly) for 26 weeks either alone, or combined with 2.5 or 5.0 ppm potassium chromate, or with 20, 100 or 500 ppm nickel chloride in drinking water. Vitamin E or selenomethionine was added to the lab chow for 29 weeks beginning 3 weeks before the start of UVR exposure. Both chromium and nickel significantly increased the UVR-induced skin cancer yield in mice. In male Skh1 mice, UVR alone induced 1.9+/-0.4 cancers/mouse, and 2.5 or 5.0 ppm potassium chromate added to drinking water increased the yields to 5.9+/-0.8 and 8.6+/-0.9 cancers/mouse, respectively. In female Skh1 mice, UVR alone induced 1.7+/-0.4 cancers/mouse, and the addition of 20, 100 or 500 ppm nickel chloride increased the yields to 2.8+/-0.9, 5.6+/-0.7 and 4.2+/-1.0 cancers/mouse, respectively. Neither vitamin E nor selenomethionine reduced the cancer yield enhancement by chromium. These results confirm that chromium and nickel, while not good skin carcinogens per se, are enhancers of UVR-induced skin cancers in Skh1 mice. Data also suggest that the enhancement of UVR-induced skin cancers by chromate may not be oxidatively mediated since the antioxidant vitamin E as well as selenomethionine, found to prevent arsenite-enhanced skin carcinogenesis, failed to suppress enhancement by chromate.
PubMed ID: 17499830
MeSH Terms: Administration, Oral; Animals; Chromium Compounds/administration & dosage; Chromium Compounds/metabolism; Chromium Compounds/toxicity*; Dose-Response Relationship, Drug; Environmental Exposure; Female; Male; Mice; Mice, Hairless; Neoplasms, Radiation-Induced/etiology*; Nickel/administration & dosage; Nickel/metabolism; Nickel/toxicity*; Oxidative Stress/drug effects; Radiation-Sensitizing Agents/administration & dosage; Radiation-Sensitizing Agents/metabolism; Radiation-Sensitizing Agents/toxicity*; Sex Factors; Skin Neoplasms/etiology*; Skin/metabolism; Skin/pathology; Statistics, Nonparametric; Sunlight/adverse effects; Trace Elements/administration & dosage; Trace Elements/metabolism; Trace Elements/toxicity; Ultraviolet Rays/adverse effects*