title: Dietary chromium and nickel enhance UV-carcinogenesis in skin of hairless mice.
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.
authors.affiliation: Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, NY 10987, USA.
authors.forename: Ahmed N
authors.initials: AN
authors.lastname: Uddin
authors.forename: Fredric J
authors.initials: FJ
authors.lastname: Burns
authors.forename: Toby G
authors.initials: TG
authors.lastname: Rossman
authors.forename: Haobin
authors.initials: H
authors.lastname: Chen
authors.forename: Thomas
authors.initials: T
authors.lastname: Kluz
authors.forename: Max
authors.initials: M
authors.lastname: Costa
mesh_terms: D000284:Administration, Oral; D000818:Animals; D017608:Chromium Compounds / Q000008:administration & dosage / Q000378:metabolism / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure; D005260:Female; D008297:Male; D051379:Mice; D008812:Mice, Hairless; D009381:Neoplasms, Radiation-Induced / Q000209:etiology*; D009532:Nickel / Q000008:administration & dosage / Q000378:metabolism / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D011838:Radiation-Sensitizing Agents / Q000008:administration & dosage / Q000378:metabolism / Q000633:toxicity*; D012737:Sex Factors; D012867:Skin / Q000378:metabolism / Q000473:pathology; D012878:Skin Neoplasms / Q000209:etiology*; D018709:Statistics, Nonparametric; D013472:Sunlight / Q000009:adverse effects; D014131:Trace Elements / Q000008:administration & dosage / Q000378:metabolism / Q000633:toxicity; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D017608:Chromium Compounds; D011838:Radiation-Sensitizing Agents; D014131:Trace Elements; D009532:Nickel