title: Metallothionein-I/II double knockout mice are no more sensitive to the carcinogenic effects of nickel subsulfide than wild-type mice.
abstract: Metallothionein (MT) is a high-affinity metal-binding protein thought to mitigate the toxicity of various metals. MT may limit the toxicity of a metal by direct binding or through action as an antioxidant for metals that generate reactive oxygen species. Nickel compounds have carcinogenic potential in humans and animals, possibly by production of oxidative stress. The impact of MT deficiency on the carcinogenic effects of nickel is unknown. Thus, groups (n=25) of male MT-I/II double knockout (MT-null) or MT wild-type (WT) mice were exposed to a single treatment of nickel (0.5 or 1.0 mg Ni3S2/site, intramuscularly, [i.m.], into both hind legs), or left untreated (control) and observed over the next 104 weeks. There were no differences in the incidence of spontaneous tumors in MT-null and WT mice. Nickel induced injection site fibrosarcomas in a dose-related fashion to a similar extent in both WT and MT-null mice. Nickel-treatment had no effect on total lung tumor incidence, although some phenotypic-specific differences occurred in the proportion of benign and malignant pulmonary tumors. Overall, MT-null mice appear no more sensitive to the carcinogenic effects of nickel than WT mice. Thus, poor MT production does not appear to be a predisposing factor for nickel carcinogenesis.
authors.affiliation: Inorganic Carcinogenesis Section, Laboratory of Comparative Carcinogenesis, National Cancer Institute at the National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA. waalkes@niehs.nih.gov
authors.forename: Michael P
authors.initials: MP
authors.lastname: Waalkes
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Kazimierz S
authors.initials: KS
authors.lastname: Kasprzak
authors.forename: Bhalchandra A
authors.initials: BA
authors.lastname: Diwan
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002273:Carcinogens / Q000633:toxicity*; D008297:Male; D008668:Metallothionein / Q000172:deficiency* / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D009374:Neoplasms, Experimental / Q000139:chemically induced / Q000235:genetics; D009532:Nickel / Q000633:toxicity*; D013997:Time Factors
chemical_list: D002273:Carcinogens; D009532:Nickel; D008668:Metallothionein; C017557:nickel subsulfide