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Oxidative DNA damage in fetal tissues after transplacental exposure to 3'-azido-3'-deoxythymidine (AZT).
Bialkowska A, Bialkowski K, Gerschenson M, Diwan BA, Jones AB, Olivero OA, Poirier MC, Anderson LM, Kasprzak KS, Sipowicz MA
Intramural Research Support Program, SAIC-Frederick Inc., Frederick Cancer Research and Development Center (FCRDC), Laboratory of Comparative Carcinogenesis, National Cancer Institute, FCRDC, Frederick, MD 21702, USA, Department of Clinical Biochemistry, University School of Medical Sciences, Bydgoszcz, Poland and Laboratory of Cellular Carcinogenesis and Tumor Promotion, National Cancer Institute, Bethesda, MD 20892, USA.
[Record supplied by publisher]
The nucleoside analogue 3'-azido-3'-deoxythymidine (AZT) has been used successfully to reduce the incidence of transplacental and perinatal transmission of the HIV virus. However, prolonged treatment with high doses of AZT is utilized in this therapy, and AZT has been found to be a perinatal carcinogen in mice. Any possible perinatal carcinogenic side effects in the human can best be managed if the mechanism is understood. AZT targets mitochondria and might cause increased intracellular production of reactive oxygen species (ROS). We tested whether transplacental AZT may cause oxidative damage in nuclear DNA of fetal tissues. CD-1 Swiss pregnant mice were treated with the transplacental carcinogenesis regimen (25 mg/day AZT, for gestation days 12-18) and tissues collected on the day of birth. Significant increases in 8-oxo-2'-deoxyguano- sine (8-oxo-dG) were found in the livers, a target tissue for transplacental carcinogenesis, and in the kidneys. A non-significant increase occurred in brain, with no change in lung. Tissues were also obtained from fetal patas monkeys (Erythrocebus patas), whose mothers had received 10 mg AZT/day during the last half of gestation. Although limited numbers of samples were available, possible increases in 8-oxo-dG were noted, relative to controls, for placenta and for fetal lung and brain (P = 0.055 for treatment-related increases in these tissues). These results suggest that an increase in reactive oxygen species could contribute to the mechanism of transplacental carcinogenesis by AZT in mice, and that this may also occur in primates.
PMID: 10783333
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