Chinese hamster fibroblasts overexpressing CuZn-superoxide dismutase undergo a global reduction in antioxidants and an increasing sensitivity of DNA to oxidative damage.
Transfection of a CuZn-superoxide dismutase (SOD) expression vector into V79 Chinese hamster cells produced clones in which CuZn-SOD activities were 2.2-3.5-fold higher than in the parental cells. An overall moderate reduction of glutathione peroxidase, glutathione reductase and glucose-6-phosphate dehydrogenase activities and of both GSSG and total glutathione levels was found. In one particular clone the catalase activity was also reduced. The pro-oxidant status established by the lower level of antioxidant defence rendered the SOD-overexpressing cells more sensitive to the production of 8-oxo-2'-deoxyguanosine by hydrogen peroxide. The data are discussed in terms of a model resembling the bacterial sox RS system.
Teixeira
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HD
Departmento de Bioquimica, Universidade de São Paulo, Brazil.
Meneghini
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R
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002460:Cell Line; D006224:Cricetinae; D004249:DNA Damage; D015870:Gene Expression; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D005978:Glutathione / Q000031:analogs & derivatives / Q000378:metabolism; D019803:Glutathione Disulfide; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D010084:Oxidation-Reduction; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism*; D014162:Transfection
D000975:Antioxidants; D006861:Hydrogen Peroxide; D005954:Glucosephosphate Dehydrogenase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005978:Glutathione; D019803:Glutathione Disulfide