Effects of the (-)-anti-11R,12S-dihydrodiol 13S,14R-epoxide of dibenzo.
The tumor suppressor protein p53 plays an important role in recognition of DNA damage and induction of subsequent cell cycle arrest. One of its target genes encodes the protein p21(WAF1), which is involved in mediation of growth arrest after DNA damage has occurred. Dibenzo[a,l]pyrene (DB[a,l]P) is a polycyclic aromatic hydrocarbon which is an exceptionally potent carcinogen. A reactive secondary metabolite of DB[a,l]P, the fjord region (-)-anti-11R,12S-dihydrodiol 13R,14S-epoxide [(-)-anti-DB[a,l]PDE] was used to investigate DNA damage via adduct formation and cell cycle arrest in human diploid fibroblast cell cultures (HDF). Synchronous HDF were exposed to increasing concentrations (0.014, 0.028 and 0.07 microM) of (-)-anti-DB[a,l]PDE and at 1, 12, 24 and 42 h after treatment cell pellets were analyzed for DNA adduct formation and cell cycle arrest. Exposure of HDF to 0.07 microM (-)-anti-DB[a,l]PDE caused a total DNA binding level of 113 pmol adducts/mg DNA (42 h after treatment). G(1) arrest was induced by this treatment, with 91% of the cells remaining in G(1) phase compared with the solvent-treated control cultures (50%) as analyzed by propidium iodide staining and flow cytometry. Further investigation of the percentage of cells in S phase by 5-bromo-2'-deoxyuridine incorporation confirmed the G(1) arrest in HDF treated with 0.07 microM (-)-anti-DB[a,l]PDE, with only 1.5% of the cells moving into S phase compared with 39% in the control 42 h after treatment. Induction of p53 and p21(WAF1) was demonstrated by western blot analysis.
Mahadevan
B
B
Department of Environmental and Molecular Toxicology, Agricultural and Life Sciences 1011, Oregon State University, Corvallis, OR 97331-7302, USA.
Luch
A
A
Seidel
A
A
Pelling
J C
JC
Baird
W M
WM
D001580:Benzopyrenes / Q000378:metabolism / Q000633:toxicity*; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects*; D002460:Cell Line; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000187:drug effects / Q000378:metabolism*; D018736:DNA Adducts / Q000096:biosynthesis*; D004249:DNA Damage; D004171:Diploidy; D004852:Epoxy Compounds / Q000378:metabolism / Q000633:toxicity*; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D016158:Genes, p53 / Q000187:drug effects; D006801:Humans; D015398:Signal Transduction / Q000187:drug effects; D013237:Stereoisomerism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D001580:Benzopyrenes; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D018736:DNA Adducts; D004852:Epoxy Compounds; D016159:Tumor Suppressor Protein p53; C121930:dibenzo(a,l)pyrene diol epoxide; D004247:DNA