Carcinogenesis, Vol. 20, No. 5, 859-865,
May 1999
© 1999 Oxford University Press
The level of DNA modification by (+)-syn-(11S,12R,13S,14R)- and (–)-anti-(11R,12S,13S,14R)-dihydrodiol epoxides of dibenzo[a,l]pyrene determined the effect on the proteins p53 and p21WAF1 in the human mammary carcinoma cell line MCF-7
1 Departments of Environmental and Molecular Toxicology and Biochemistry and Biophysics, Oregon State University, Agricultural and Life Sciences 1011, Corvallis, OR 97331-7302, USA,
2 Institute of Toxicology and Environmental Hygiene, Technical University of Munich, 80636 Munich, Germany,
3 Biochemistry and Molecular Biology Program, Purdue University, West Lafayette, IN 47907, USA,
4 Institute of Toxicology, University of Mainz, 55131 Mainz, Germany and
5 GSF National Research Center for Environment and Health, Institute of Toxicology, 85764 Neuherberg, Germany
The polycyclic aromatic hydrocarbon (PAH) dibenzo[a,l]pyrene (DB[a,l]P), the most carcinogenic PAH tested in rodent bioassays, exerts its pathobiological activity via metabolic formation of electrophilically reactive DNAbinding fjord region (+)-syn-(11S,12R,13S,14R)- or (–)-anti-(11R,12S,13S,14R)-DB[a,l]P-dihydrodiol epoxides (DB[a,l]PDEs). DB[a,l]P is metabolized to these DB[a,l]PDEs which bind to DNA in human mammary carcinoma MCF-7 cells. The molecular response of MCF-7 cells to DNA damage caused by DB[a,l]PDEs was investigated by analyzing effects on the expression of the tumor suppressor protein p53 and one of its target gene products, the cyclin-dependent kinase inhibitor p21WAF1. Treatment of MCF-7 cells with (+)-syn- and (–)-anti-DB[a,l]PDE at a concentration range of 0.001–0.1 µM resulted in DB[a,l]PDE–DNA adduct levels between 2 and 30, and 3 and 80 pmol/mg DNA, respectively, 8 h after exposure. (–)-anti-DB[a,l]PDE exhibited a higher binding efficiency that correlated with a significantly stronger p53 response at low concentrations of the dihydrodiol epoxides. The level of p53 increased by 6–8 h after treatment. The p21WAF1 protein amount exceeded control levels by 12 h and remained elevated for 96 h. At a dose of 0.01 µM (+)-syn-DB[a,l]PDE, an increase in p21WAF1 was observed in the absence of a detectable change in p53 levels. The results indicate that the increase in p53 induced by DB[a,l]PDEs in MCF-7 cells requires an adduct level of ~15 pmol/mg DNA and suggest that the level of adducts rather than the specific structure of the DB[a,l]PDE–DNA adduct formed triggers the p53 response. The PAH–DNA adduct level formed may determine whether p53 and p21WAF1 pathways respond, resulting in cell-cycle arrest, or fail to respond and increase the risk of mutation induction by these DNA lesions.
Abbreviations: (–)-anti-DB[a,l]PDE, dibenzo[a,l]pyrene-11R,12S-dihydrodiol 13S,14R-epoxide; (+)-anti-B[a]PDE, B[a]P-7R,8S-dihydrodiol 9S,10R-epoxide; (+)-syn-DB[a,l]PDE, dibenzo[a,l]pyrene-11S,12R-dihydrodiol 13S,14R-epoxide; B[a]P, benzo[a]pyrene; CDK, cyclin-dependent kinase; DB[a,l]P, dibenzo[a,l]pyrene; DB[a,l]PDE(s), DB[a,l]P-11,12-dihydrodiol 13,14-epoxide(s); DMSO, dimethyl sulfoxide; FCS, fetal calf serum; PAGE, polyacrylamide gel electrophoresis; PAH(s), polycyclic aromatic hydrocarbon(s); PBS, phosphate-buffered saline; PMSF, phenylmethylsulfonyl fluoride; SDS, sodium dodecyl sulfate; TBS, Tris-buffered saline; TCPI, trypsin–chymotrypsin protease inhibitor.
6 To whom correspondene should be addressed Email: william.baird{at}orst.edu
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  D. R. Lloyd and P. C. Hanawalt p53 Controls Global Nucleotide Excision Repair of Low Levels of Structurally Diverse Benzo(g)chrysene-DNA Adducts in Human Fibroblasts Cancer Res., September 15, 2002; 62(18): 5288 - 5294. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Davis, S. Bhana, A. J. Shorrocks, and F. L. Martin Oestrogens induce G1 arrest in benzo[a]pyrene-treated MCF-7 breast cells whilst enhancing genotoxicity and clonogenic survival Mutagenesis, September 1, 2002; 17(5): 431 - 438. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Mahadevan, A. Luch, A. Seidel, J. C. Pelling, and W. M. Baird 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 Carcinogenesis, January 1, 2001; 22(1): 161 - 169. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Q. A. Khan and A. Dipple Diverse chemical carcinogens fail to induce G1 arrest in MCF-7 cells Carcinogenesis, August 1, 2000; 21(8): 1611 - 1618. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Nakanishi, X.-H. Pei, K. Takayama, F. Bai, M. Izumi, K. Kimotsuki, K. Inoue, T. Minami, H. Wataya, and N. Hara Polycyclic Aromatic Hydrocarbon Carcinogens Increase Ubiquitination of p21 Protein after the Stabilization of p53 and the Expression of p21 Am. J. Respir. Cell Mol. Biol., June 1, 2000; 22(6): 747 - 754. [Abstract] [Full Text]
|
|
|
|
|
|
D. R. Lloyd and P. C. Hanawalt p53-dependent Global Genomic Repair of Benzo[a]pyrene-7,8-diol-9,10-epoxide Adducts in Human Cells Cancer Res., February 1, 2000; 60(3): 517 - 521. [Abstract] [Full Text]
|
|