Induction of 8-oxo-dGTPase activity in human lymphoid cells and normal fibroblasts by oxidative stress.
The pre-mutagen 8-Oxo-2'-deoxyguanosine-5'-triphosphate (8-oxo-dGTP) is formed during normal cellular metabolism and its incorporation into DNA leads to transversion mutations. Human cells possess the hMTH-1 gene encoding the enzyme 8-oxo-dGTPase, which catalyzes the hydrolysis of 8-oxo-dGTP to the corresponding 8-oxo-dGMP, preventing mutations. To elucidate the involvement of 8-oxo-dGTPase in carcinogenesis, we studied hMTH-1 gene expression and enzyme activity in response to oxidative stress to human skin fibroblasts and Jurkat cells. In fibroblasts, ranges from 0 to 100 microM H(2)O(2) caused a 2-fold induction of hMTH-1-mRNA expression and a 3-fold induction of enzyme activity. A 1.7-fold induction of mRNA expression and a 3.5-fold induction of enzyme activity was obtained in Jurkat cells after treatment ranging from 0 to 300 microM H(2)O(2). Cytotoxic concentrations of hydrogen peroxide lead to an almost complete loss of enzyme activity and an inhibition of hMTH-1 mRNA expression. Induction of hMTH-1 gene expression was prevented by addition of actinomycin D and cycloheximide. These data indicate the inducibility of the hMTH-1 gene expression and enzyme activity by prooxidative molecules, such as hydrogen peroxide. These parameters can thus be used as a marker of oxidative stress.
Meyer
F
F
Department of Toxicology, University Medical School of Hamburg, Grindelallee 117, D-20146, Hamburg, Germany.
Fiala
E
E
Westendorf
J
J
D002470:Cell Survival / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D045643:DNA Repair Enzymes; D005347:Fibroblasts / Q000201:enzymology; D006153:Guanosine Diphosphate / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D019169:Jurkat Cells / Q000201:enzymology; D007700:Kinetics; D008214:Lymphocytes / Q000201:enzymology*; D009841:Oligonucleotides / Q000378:metabolism; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000502:physiology*; D010744:Phosphoric Monoester Hydrolases / Q000096:biosynthesis*; D014176:Protein Biosynthesis; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction
D009841:Oligonucleotides; D016877:Oxidants; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D006861:Hydrogen Peroxide; D010744:Phosphoric Monoester Hydrolases; C078207:8-oxodGTPase; D045643:DNA Repair Enzymes