Impact of copper on the induction and repair of oxidative DNA damage, poly(ADP-ribosyl)ation and PARP-1 activity.
Copper is an essential trace element involved, among other functions, in enzymatic antioxidative defense systems. However, nonprotein bound copper ions have been shown to generate reactive oxygen species. To gain insight into the discrepancy between the protective properties of copper on the one hand and its toxicity on the other hand, we examined the genotoxic effects of CuSO(4) in cultured human cells. Here we report that copper, at cytotoxic concentrations, induces oxidative DNA base modifications and DNA strand breaks. However, at lower noncytotoxic concentrations, copper inhibits the repair of oxidative DNA damage induced by visible light. As a first mechanistic hint, inhibition of H(2)O(2)-induced poly(ADP-ribosyl)ation was identified in cultured cells and further experiments demonstrated a strong inhibition of the activity of isolated poly(ADP-ribose)polymerase-1 (PARP-1) by copper. Bioavailability studies of copper showed a dose-dependent uptake in cells and pointed out the relevance of the applied concentrations. Taken together, the results indicate that copper, under conditions of either disturbed homeostasis or overload due to high exposure, exerts defined genotoxic effects. Hence, a balance needs to be maintained to ensure sufficient uptake and to prevent overload.
Schwerdtle
Tanja
T
Institut für Lebensmitteltechnologie und Lebensmittelchemie, Technische Universität Berlin, Berlin, Germany.
Hamann
Ingrit
I
Jahnke
Gunnar
G
Walter
Ingo
I
Richter
Constanze
C
Parsons
Jason L
JL
Dianov
Grigory L
GL
Hartwig
Andrea
A
D003300:Copper / Q000378:metabolism / Q000494:pharmacology*; D053960:DNA Breaks; D004249:DNA Damage / Q000187:drug effects*; D004260:DNA Repair / Q000187:drug effects*; D006367:HeLa Cells; D006801:Humans; D010084:Oxidation-Reduction; D000071137:Poly (ADP-Ribose) Polymerase-1; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*
D011064:Poly Adenosine Diphosphate Ribose; D003300:Copper; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases