Production of Oxidative DNA Damage during the Metabolic Activation of Benzo[a]pyrene in Human Mammary Epithelial Cells Correlates with Cell Killing

• Published in: Proceedings of the National Academy of Sciences - PNAS 1988-06, Vol.85 (12), p.4365-4368
• Main Authors: Leadon, Steven A., Stampfer, Martha R., Bartley, Jack
• Format: Article
• Language: English
• Subjects: 550201 - Biochemistry- Tracer Techniques; 560120 - Radiation Effects on Biochemicals, Cells, & Tissue Culture; 560300 - Chemicals Metabolism & Toxicology; Adducts; ALCOHOLS; ANIMAL TISSUES; ANIMALS; ANTIBODIES; AROMATICS; AZINES; BASIC BIOLOGICAL SCIENCES; Benzo(a)pyrene - metabolism; Benzo(a)pyrene - toxicity; BENZOPYRENE; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; Biological and medical sciences; BIOLOGICAL EFFECTS; BIOLOGICAL RADIATION EFFECTS; Biotransformation; BODY; Breast - drug effects; Breast - metabolism; Breast - pathology; Carcinogenesis, carcinogens and anticarcinogens; Carcinogens; CELL KILLING; Cell Survival - drug effects; Cells; Cells, Cultured; Chemical agents; COBALT 60; COBALT ISOTOPES; CONDENSED AROMATICS; DNA; DNA Damage; DNA Repair; DNA Replication - drug effects; DOSE-RESPONSE RELATIONSHIPS; ELECTROMAGNETIC RADIATION; ENZYMES; Epithelial Cells; EPITHELIUM; Epithelium - drug effects; Epithelium - metabolism; Female; FEMALES; GAMMA RADIATION; GLANDS; GLYCOLS; HETEROCYCLIC COMPOUNDS; Humans; HYDROCARBONS; HYDROGEN COMPOUNDS; HYDROXY COMPOUNDS; Indirect DNA damage; INTERMEDIATE MASS NUCLEI; INTERNAL CONVERSION RADIOISOTOPES; IONIZING RADIATIONS; ISOMERIC TRANSITION ISOTOPES; ISOTOPES; MAMMALS; MAMMARY GLANDS; MAN; Medical sciences; METABOLIC ACTIVATION; MINUTES LIVING RADIOISOTOPES; MONOCLONAL ANTIBODIES; NUCLEI; NUCLEIC ACIDS; ODD-ODD NUCLEI; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; ORGANS; OXIDOREDUCTASES; PRIMATES; PYRIMIDINES; Radiation damage; RADIATION EFFECTS; RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT; RADIATIONS; RADICALS; RADIOISOTOPES; Reactive oxygen species; SUPEROXIDE DISMUTASE; SUPEROXIDE RADICALS; THYMINE; TISSUES; TRITIUM COMPOUNDS; Tumors; URACILS; VERTEBRATES; WOMEN; YEARS LIVING RADIOISOT
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.85.12.4365

We have studied the generation of reactive oxygen species during the metabolism of a carcinogen, benzo[a]pyrene, by human mammary epithelial cells. We have quantitated the production of one type of oxidative DNA damage, thymine glycols, by using a monoclonal antibody specific to this base modification. Thymine glycols were produced in DNA in a dose-dependent manner after exposure of human mammary epithelial cells to benzo[a]pyrene. The number of thymine glycols formed in the DNA was similar to that of 7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene covalently bound to the DNA. Exposure of cells to the carcinogen in the presence of superoxide dismutase, which reduces superoxide anions, inhibited the production of thymine glycols and increased cell survival but had little effect on adduct formation. At equitoxic doses, ≈ 10-fold more thymine glycols were formed after exposure to benzo[a]pyrene than to γ -irradiation. Thymine glycols, produced by either agent, were efficiently removed from the DNA of the cells. Since thymine glycols represent only a portion of the oxidative damage possibly produced, our results indicate that the total amount of oxidative damage induced during the exposure of human mammary epithelial cells to benzo[a]pyrene greatly exceeds the amount produced by direct adduct formation and that this indirect damage plays an important role in the cytotoxicity of benzo[a]pyrene.