Effects of the (-)-anti-11R,12S-dihydrodiol 13S,14R-epoxide of dibenzo[a,l]pyrene on DNA adduct formation and cell cycle arrest in human diploid fibroblasts
B. Mahadevan et al., Effects of the (-)-anti-11R,12S-dihydrodiol 13S,14R-epoxide of dibenzo[a,l]pyrene on DNA adduct formation and cell cycle arrest in human diploid fibroblasts, CARCINOGENE, 22(1), 2001, pp. 161-169
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 gro
wth arrest after DNA damage has occurred. Dibenzo[a,l]pyrene (DB[a,l]P) is
a polycyclic aromatic hydrocarbon which is an exceptionally potent carcinog
en. 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 inves
tigate DNA damage via adduct formation and cell cycle arrest in human diplo
id fibroblast cell cultures (HDF). Synchronous HDF were exposed to increasi
ng concentrations (0.014, 0.028 and 0.07 muM) of (-)-anti-DB[a,l]PDE and at
1, 12, 24 and 42 h after treatment cell pellets were analyzed for DNA addu
ct formation and cell cycle arrest. Exposure of HDF to 0.07 muM (-)-antiDB[
a,l]PDE caused a total DNA binding level of 113 pmol adducts/mg DNA (42 h a
fter 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 cu
ltures (50%) as analyzed by propidium iodide staining and flow cytometry, F
urther investigation of the percentage of cells in S phase by 5-bromo-2'-de
oxyuridine incorporation confirmed the G1 arrest in HDF treated with 0.07 m
uM (-)-anti-DB[a,l]PDE, with only 1.5% of the cells moving into S phase com
pared with 39% in the control 42 h after treatment. Induction of p53 and p2
1(WAF1) was demonstrated by western blot analysis.