title: V-Ha-Ras overexpression induces superoxide production and alters levels of primary antioxidant enzymes.
abstract: Reactive oxygen species have been shown to play important roles in v-Ha-Ras mitogenic signaling. We hypothesized that v-Ha-Ras overexpression would induce superoxide production, and therefore modify expression of the primary antioxidant enzyme system. We have demonstrated that immortal rat kidney epithelial cells stably transduced with constitutively active v-Ha-ras produced significantly larger amounts of superoxide radical than wild-type or vector-transfected control cells. The levels of the primary antioxidant enzymes copper- and zinc-containing superoxide dismutase, manganese-containing superoxide dismutase, catalase, and glutathione peroxidase were increased in the superoxide-overproducing cells. DNA-binding activities of the transcription factors activator protein-1, activator protein-2, and nuclear factor-kappaB were all enhanced in the superoxide-overproducing cells. These v-Ha-ras transduced cells also had a shortened cell doubling time and higher plating efficiency, and displayed greater constitutive levels of phosphorylated mitogen-activated protein kinases. These data demonstrate that v-Ha-Ras overexpression increases superoxide production and this apparently affects a wide variety of cell signaling and redox systems.
authors.affiliation: Department of Radiology and Holden Comprehensive Cancer Center, The University of Iowa, Iowa City 52242-1181, USA.
authors.forename: J Q
authors.initials: JQ
authors.lastname: Yang
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.forename: Y
authors.initials: Y
authors.lastname: Huang
authors.forename: H J
authors.initials: HJ
authors.lastname: Zhang
authors.forename: F E
authors.initials: FE
authors.lastname: Domann
authors.forename: G R
authors.initials: GR
authors.lastname: Buettner
authors.forename: L W
authors.initials: LW
authors.lastname: Oberley
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism*; D002455:Cell Division; D002461:Cell Line, Transformed / Q000378:metabolism; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D004847:Epithelial Cells / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism*; D007668:Kidney / Q000166:cytology; D020935:MAP Kinase Signaling System; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D015689:Oncogene Protein p21(ras) / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D010084:Oxidation-Reduction; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000502:physiology; D013482:Superoxide Dismutase / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection
chemical_list: D000975:Antioxidants; D004268:DNA-Binding Proteins; D016328:NF-kappa B; D011993:Recombinant Fusion Proteins; D018808:Transcription Factor AP-1; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D013481:Superoxides; D004247:DNA; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D020928:Mitogen-Activated Protein Kinases; D015689:Oncogene Protein p21(ras)