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Stereoselective Activation of Dibenzo[a,l]pyrene to (-)-Anti (11R,12S,13S,14R)- And (+)-syn(11S,12R,13S,14R)-11,12-diol-13,14-epoxides Which Bind Extensively to Deoxyadenosine Residues of DNA in the Human Mammary Carcinoma Cell Line MCF-7

S L Ralston, A Seidel, A Luch, K L Platt, W M Baird

Carcinogenesis. 1995 Dec;16(12):2899-907.

PMID: 8603462

Abstract:

Dibenzo[a,l]pyrene (DB[a,l]P) is an environmental contaminant and a very potent carcinogen. DB[a,l]P exceeds the carcinogenic potency of both benzo[a]pyrene and 7,12-dimethylbenz[a]anthracene in rodent bioassays. Previous studies demonstrated that DB[a,l]P is metabolized to DB[a,l]P-11,12-diol-13,14-epoxide (DB[a,l]PDE) in the human mammary carcinoma cell line MCF-7. In the present study the major DNA adducts formed in DB[a,l]P-treated MCF-7 cells have been identified through the use of 33P-postlabeling. TLC and HPLC. DB[a,l]P is metabolically activated in MCF-7 cells to form large amounts of three major DNA adducts and smaller amounts of three other adducts. The three major DNA adducts are with deoxyadenosine: two are formed by reaction of (+)-syn-DB[a,l]PDE (11S,12R,13S,14R), the third by reaction of (-)-anti-DB[a,l]PDE (11R,12S,13S,14R). The results demonstrate that DB[a,l] is stereoselectively metabolized in MCF-7 cells to form one enantiomer of each diol epoxide diastereomer; (+)-syn-DB[a,l]PDE and (-)-anti-DB[a,l]PDE. The high extent of binding of these diol epoxides to deoxyadenosine in DNA of MCF-7 cells may help to explain the very high carcinogenic potency of DB[a,l]P and suggests that DB[a,l]P could also pose a carcinogenic threat to humans.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP191300-A Dibenzo[a,l]pyrene Dibenzo[a,l]pyrene 191-30-0 Price
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