Induction of oxidative stress and protection against hydrogen peroxide-mediated cytotoxicity by the superoxide dismutase-mimetic complex copper-putrescine-pyridine.
The low molecular weight Cu2Zn2-superoxide dismutase (SOD) active centre analogue copper-putrescine-pyridine (Cu-PuPy, N,N'-bis(2-pyridylmethylene)1,4-butanediamine(N,N',N",N")-Cu (II)- -diperchlorate) has been shown to dismutate superoxide with high efficiency. In the presence of glutathione it sustains the production of H2O2 via redox cycling. We investigated the influence of Cu-PuPy on the glutathione status and the clonogenic survival of Chinese hamster ovary (CHO) cells. At 0.05 mM Cu-PuPY was not toxic and exerted only a minor effect on cellular glutathione. At Cu-PuPy concentrations of 0.1-0.5 mM glutathione became increasingly oxidized and was depleted during treatment while toxicity dramatically increased. The time course of toxicity was unusual: after passing a minimum at 50 or 100 min (0.5 mM or 0.2 mM Cu-PuPy, respectively), clonogenic survival increased by two orders of magnitude in the following 50 min. On the other hand, Cu-PuPy protected cells effectively against toxic doses of hydrogen peroxide. We conclude that Cu-PuPy combines a prooxidant and an antioxidant mode of action that sequentially modify the survival response of CHO cells: initial production of hydrogen peroxide by Cu-PuPy-catalysed glutathione oxidation leads to the intracellular accumulation of potentially toxic radical intermediates that may be inactivated via superoxide dismutation upon further treatment with Cu-PuPy.
Nagele
A
A
Strahlenbiologisches Institut, Ludwig-Maximilians-Universität, München, Federal Republic of Germany.
Felix
K
K
Lengfelder
E
E
D000818:Animals; D016466:CHO Cells / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003300:Copper / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D005978:Glutathione / Q000032:analysis; D006861:Hydrogen Peroxide / Q000037:antagonists & inhibitors*; D009942:Organometallic Compounds / Q000494:pharmacology*; D010084:Oxidation-Reduction / Q000187:drug effects; D012545:Schiff Bases / Q000494:pharmacology*; D013482:Superoxide Dismutase; D013997:Time Factors
D009942:Organometallic Compounds; D012545:Schiff Bases; D003300:Copper; C064004:N,N'-bis(2-pyridylmethylene)-1,4-butanediamine (N,N',N'',N''')-Cu(II)diperchlorate; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase; D005978:Glutathione