Benzo(a)pyrene:DNA adduct formation in normal human mammary epithelial cell cultures and the human mammary carcinoma T47D cell line.

The benzo(a)pyrene (BaP):DNA adducts formed in normal human mammary epithelial cell cultures and the human mammary carcinoma T47D cell line were analyzed by chromatography and acid hydrolysis of the BaP:deoxyribonucleoside adducts to BaP:purine adducts and BaP:tetraols. Human mammary epithelial cell cultures and human mammary carcinoma T47D cells were exposed to [3H]BaP for 24 h, and the levels of binding were 81 and 182 pmol BaP/mg DNA in normal and T47D cultures, respectively. Analysis of BaP:deoxyribonucleoside adducts resolved by immobilized boronate chromatography and reversephase high-performance liquid chromatography demonstrated the presence of three BaP:deoxyribonucleoside adducts in both cells: M2, MS1, and MS2 in a ratio of 1.6:1:14. Two adducts (MS1 and MS2) bound to the immobilized boronate column indicating the presence of cis-vicinal hydroxyl groups, a configuration which would result from reaction of 7 beta, 8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydroBaP (anti-BaPDE) with DNA. MS2 was identified as (+)-anti-BaPDE:deoxyguanosine (dGuo) for it cochromatographed with a [14C]-(+)-anti-BaPDE:dGuo marker, the BaP:purine hydrolysis product of MS2 cochromatographed with [14C]-(+)-anti-BaPDE:guanine, and the tetraol hydrolysis products cochromatographed with (+/-)-anti-BaPDE:tetraols. MS1 was identified as (-)-anti-BaPDE:dGuo for MS1 eluted in the same relative position as a (-)-anti-BaPDE:dGuo marker, the BaP:purine hydrolysis product of MS1 cochromatographed with [14C]-(+)-anti-BaPDE:guanine, and the tetraol hydrolysis products cochromatographed with (+/-)-anti-BaPDE:tetraols. Thus, both adducts that bound to the immobilized boronate column were formed from (+/-)-anti-BaPDE. One major adduct that did not contain cis-vicinal hydroxy groups, M2, was detected in both cell types. M2 was formed from (+/-)-7 beta, 8 alpha-dihydroxy-9 beta, 10 beta-epoxy-7,8,9,10-tetrahydroBaP (syn-BaPDE) as M2 eluted in the same relative position as a syn-BaPDE:dGuo adduct marker and the tetraol hydrolysis products of M2 cochromatographed with tetraols formed from (+/-)-syn-BaPDE. The isolation of the individual BaP:DNA adducts followed by acid hydrolysis allowed the identification of the BaP:DNA adducts formed in human mammary cell cultures and demonstrated the presence of (-)-anti-BaPDE:dGuo. Thus, this work provides the first evidence, other than cochromatography, that (-)-anti-BaPDE is formed in cell systems and reacts with DNA in cells to form (-)-anti-BaPDE:dGuo.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparative metabolism and macromolecular binding of benzo[a]pyrene in explant cultures of human bladder, skin, bronchus and esophagus from eight individuals.

Benzo[a]pyrene (B[a]P) metabolism and macromolecular binding have been studied in explants from 4 tissues, bladder, skin, bronchus and esophagus from 8 donors sampled within 4 h after death. Explants were incubated with [3H]benzo[a]pyrene for 24 h, then the metabolites extracted and analyzed by high-pressure liquid chromatography. Fibroblasts were grown from explants from 2 patients and also incubated with B[a]P. Metabolite profiles were qualitatively the same for explants and fibroblasts with similar product ratios, although fibroblasts were less active in B[a]P metabolism. DNA binding studies showed a broad variance between patients and tissues with the relative distribution being widest in bladder, followed by skin, bronchus and esophagus, respectively.

Two-dimensional gel electrophoretic comparison of cytoplasmic proteins in C3H10T1/2 cells, a chemically transformed 10T1/2 line, and a transformation resistant C3H mouse ventral prostate cell line.

The cytoplasmic proteins from three cell lines derived from the C3H mouse were compared after treatment with benzo(a)pyrene by two-dimensional gel electrophoresis and computerized image analysis. The three C3H lines were the transformable 10T1/2, the transformation resistant CVP and the methylcholanthrene transformed 10T1/2Cl line. Specialized algorithms were used to analyze gel images to record and compare individual proteins in the three cytoplasmic preparations. Multiple replicate gels were used to construct a master image to insure all the proteins were represented in the analytical system. In studies designed to examine the efficacy of utilizing image analysis, benzo(a)pyrene treatment caused significant alteration in the expression of numerous proteins in all three cell lines. Comparative analysis between cell types also showed most of the induced and repressed proteins were unique to a given cell line and did not match the induced or repressed proteins in either of the other cell lines. These results suggest that the response to chemical carcinogen treatment may be somewhat cell-specific and result in a variable response to the cells ability to respond to the chemical insult.