title: Effects of oxidative stress on the nuclear translocation of extracellular superoxide dismutase.
abstract: The effect of oxidative stress on the cellular uptake and nuclear translocation of extracellular superoxide dismutase (EC-SOD) was investigated. EC-SOD was incorporated from conditioned medium of stable EC-SOD expressing CHO-EK cells into 3T3-L1 cells within 15 min. The uptake was clearly inhibited by the addition of heparin at a concentration of 0.4 microg/ml. Treatment of the 3T3-L1 cells with H(2)O(2) (5 mM for 5 min), followed by incubation with CHO-EK medium downregulated the uptake of EC-SOD. Nuclear translocation of the incorporated EC-SOD was clearly enhanced by H(2)O(2) treatment following incubation with the CHO-EK medium. EC-SOD is the only anti-oxidant enzyme which is known at this time to be actively transported into nuclei. The results obtained here suggest that the upregulation of the nuclear translocation of EC-SOD by oxidative stress might play a role in the mechanism by which the nucleus is protected against oxidative damage of genomic DNA.
authors.affiliation: Department of Biochemistry, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan. biochook@hyo-med.ac.jp
authors.forename: Tomomi
authors.initials: T
authors.lastname: Ookawara
authors.forename: Hironobu
authors.initials: H
authors.lastname: Eguchi
authors.forename: Masashi
authors.initials: M
authors.lastname: Nishimura
authors.forename: Takako
authors.initials: T
authors.lastname: Kizaki
authors.lastname: Eiji Takayama
authors.forename: Daizoh
authors.initials: D
authors.lastname: Saitoh
authors.forename: Hideki
authors.initials: H
authors.lastname: Ohno
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D016475:3T3 Cells; D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D016466:CHO Cells; D006224:Cricetinae; D017077:Culture Media, Conditioned; D004249:DNA Damage; D005110:Extracellular Space / Q000201:enzymology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D051379:Mice; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism*
chemical_list: D017077:Culture Media, Conditioned; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase