Modification of the in vitro cytotoxicity of hydrogen peroxide by iron complexes.
The effect of a range of iron chelates on the cytotoxicity of H2O2 was studied on a mammalian epithelial cell line. Iron complexes which were internalised enhanced the cytotoxicity of H2O2 measured by delayed thymidine incorporation. Iron complexed to 8-hydroxyquinoline (Fe/8-HQ) potentiated the cytotoxicity of 50 microM by 38% and Fe/dextran by 23%. Pre-exposure of cells to Fe/dextran at 4 degrees C did not result in any potentiation of H2O2-induced cytotoxicity which we ascribe to failure of the Fe/dextran to be endocytosed at low temperature. Iron complexes which are slowly taken up or remain extracellular protected the cells from H2O2-induced cytotoxicity. Thus, Fe/EDTA inhibited the cytotoxicity of 50 microM H2O2 by 33%; Fe/ADP by 80% and Fe/ATP by 88%, suggesting mutual extracellular detoxification.
Jonas
S K
SK
Department of Biology and Biochemistry, Brunel University, Uxbridge, Middlesex.
Riley
P A
PA
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D004261:DNA Replication / Q000187:drug effects; D003911:Dextrans / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D004847:Epithelial Cells; D006861:Hydrogen Peroxide / Q000633:toxicity*; D007502:Iron Chelating Agents / Q000494:pharmacology*; D008322:Mammals; D010084:Oxidation-Reduction; D015125:Oxyquinoline / Q000494:pharmacology; D013696:Temperature
D003911:Dextrans; D007502:Iron Chelating Agents; D015125:Oxyquinoline; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D004492:Edetic Acid; D006861:Hydrogen Peroxide