title: Antioxidant enzymes are elevated in dimethylbenz[a]anthracene-induced neoplastic murine keratinocytes containing an active rasHa oncogene.
abstract: Antioxidant enzyme activities and peroxidation potential were measured in primary mouse keratinocytes and neoplastic keratinocytes containing an active rasHa oncogene. In neoplastic cell lines, SP-1 and 308, the activities of Cu, Zn-superoxide dismutase, catalase, and glutathione transferase were significantly elevated. The peroxidation potential was lower in cell homogenates prepared from neoplastic keratinocytes than in those prepared from normal keratinocytes. Consistently, the neoplastic 308 cell line was found to be more resistant than the normal keratinocytes to cytotoxicity induced by UV-B irradiation. The present study suggests that the enhanced antioxidant defense system protects the initiated cells from UV-B-induced oxidative stress, and that the enhanced enzymic antioxidant defense system is potentially a mechanism favoring the selective growth of neoplastic keratinocytes.
authors.affiliation: Department of Clinical Chemistry, University Central Hospital of Turku, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Lehtola
authors.forename: L
authors.initials: L
authors.lastname: Laurikainen
authors.forename: L
authors.initials: L
authors.lastname: Leino
authors.forename: M
authors.initials: M
authors.lastname: Ahotupa
authors.forename: K
authors.initials: K
authors.lastname: Punnonen
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D002470:Cell Survival / Q000528:radiation effects; D015972:Gene Expression Regulation, Neoplastic; D011905:Genes, ras; D005982:Glutathione Transferase / Q000378:metabolism; D015603:Keratinocytes / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D018384:Oxidative Stress / Q000502:physiology; D012878:Skin Neoplasms / Q000139:chemically induced / Q000201:enzymology* / Q000235:genetics*; D013482:Superoxide Dismutase / Q000378:metabolism; D014343:Trypan Blue / Q000493:pharmacokinetics; D014407:Tumor Cells, Cultured / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D015127:9,10-Dimethyl-1,2-benzanthracene; D002374:Catalase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; D014343:Trypan Blue