Morphological transformation and DNA adduct formation by dibenz[a,h]anthracene and its metabolites in C3H10T1/2CL8 cells

The major routes of metabolic activation of dibenz[a,h]-anthracene (DBA) have been studied in transformable C3H10T1/2CL8 (C3H10T1/2) mouse embryo fibroblasts in culture. The morphological transforming activities of three potential intermediates formed by metabolism of DBA by C3H10T1/2 cells, trans-3,4-dihydroxy-3,4-dihydro-DBA-(DBA-3,4-diol), trans-dihydroxy-3,4-dihydro-DBA-anti-1,2-oxide (DBA-3,4-diol-1,2-oxide) and DBA-5,6-oxide were determined. DBA-3,4-diol-1,2-oxide was a strong morphological transforming agent giving a mean of 73% dishes with Type II or III foci and 1.63 Type II and III foci per dish at 0.5 microgram/ml. DBA-3,4-diol produced a mean of 42% dishes with Type II or III foci and 0.81 Type II and III foci per dish at 2.5 micrograms/ml. DBA gave a mean of 24% dishes with Type II or III foci and 0.29 Type II and III foci per dish at 2.5 micrograms/ml. DBA-5,6-oxide was found to be inactive. DNA adducts of DBA, DBA-3,4-diol, DBA-3,4-diol-1,2-oxide, DBA-1,4/2,3-tetrol and DBA-5,6-oxide in C3H10T1/2 cells were analyzed by 32P-postlabeling method. DBA gave 11 adducts, nine of which were observed in the DNA of cells treated with DBA-3,4-diol and seven from cells treated with DBA-3,4-diol-1,2-oxide. Two of these adducts that appear in each of the treatment groups have been identified as the product of the interaction of DBA-3,4-diol-1,2-oxide with 2'-deoxyguanosine. Furthermore, there is evidence for DBA-DNA adducts in cells treated with DBA, DBA-3,4-diol and DBA-3,4-diol-1,2-oxide arising from metabolism to (+,-)-trans,trans-3,4,10,11-tetrahydroxy-3,4,10,11-tetrahydro-DBA (DBA-3,4,10,11-bis-diol). These results are based on co-migration of C3H10T1/2 DNA adducts with skin DNA adducts formed after topical treatment of mice with DBA-3,4,10,11-bis-diol. In C3H10T1/2 cells, DBA is metabolically activated through DBA-3,4-diol, which is further activated via the DBA-3,4-diol-1,2-oxide and DBA-3,4,10,11-bis-diol pathways. No evidence is provided for the metabolism of DBA by the K-region pathway.

N-nitrosodiethylamine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone induced morphological transformation of C3H/10T1/2CL8 cells expressing human cytochrome P450 2A6

Transfection of specific genes into cells capable of expressing chemically induced morphological cell transformation provides a valuable approach to study the mechanisms of action of carcinogens. A human cytochrome P450 isozyme, CYP2A6, has been successfully expressed from a retroviral vector in transformable C3H/10T1/2 (10T1/2) mouse embryo fibroblasts and these resulting 10T1/2 clones were evaluated for the cytotoxic and transforming activities of two nitrosamines, 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanone (NNK) and N-nitrosodiethylamine (DEN). 10T1/2 clone 29 cells, which expressed high levels of CYP2A6 activity, were responsive to the cytotoxic and morphological transforming effects of DEN or NNK on a concentration-related basis. In 10T1/2 clone 29 cells, DEN at 600 micrograms/ml decreased cell survival to 67%, and induced 0.5 type II&III foci/dish. NNK at 400 micrograms/ml administered to 10T1/2 clone 29 cells decreased survival to 57% and induced 0.43 type II&III foci/dish. Wild-type 10T1/2 cells and 10T1/2 clone 4 cells (infected with the vector but not expressing the CYP2A6 activity) were unresponsive. These results indicate that expression of a cDNA coding for cytochrome P450 in 10T1/2 cells can provide information about the role of the enzyme in the activities of chemical carcinogens and also increase the sensitivity of 10T1/2 cells to a larger number of classes of chemical carcinogens.

Morphological transformation and DNA adduct formation by benz[j]aceanthrylene and its metabolites in C3H10T1/2CL8 cells: evidence for both cyclopenta-ring and bay-region metabolic activation pathways

Benz[j]aceanthrylene (B[j]A), a cyclopenta-fused polycyclic aromatic hydrocarbon related to 3-methylcholanthrene, has been studied to identify the major routes of metabolic activation in transformable C3H10T1/2CL8 (C3H10T1/2) mouse embryo fibroblasts in culture. Previous studies have reported that the major (55% of total) B[j]A metabolite formed by C3H10T1/2 cells was (+/-)-trans-9,10-dihydro-9,10-dihydroxy-B[j]A (B[j]A-9,10-diol), the dihydrodiol in the bay-region ring, with moderate amounts (14% of total) of (+/-)-trans-1,2-dihydro-1,2-dihydroxy-B[j]A (B[j]A-1,2-diol), the cyclopenta-ring dihydrodiol. The morphological transforming activities of three potential intermediates formed by metabolism of B[j]A by C3H10T1/2 cells, (+/-)-anti-trans-9,10-dihydro-9,10-dihydroxy-B[j]A-7,8-oxide (B[j]A-diol-epoxide), B[j]A-9,10-oxide, and B[j]A-1,2-oxide as well as the two B[j]A-dihydrodiols were examined. B[j]A, B[j]A-diol-epoxide, B[j]A-1,2-oxide, and B[j]A-9,10-diol were found to have moderate to strong activities with B[j]A-diol-epoxide the most active compared to B[j]A, while B[j]A-1,2-diol was inactive. B[j]A-9,10-oxide was found to be a weak transforming agent. At 0.5 microgram/ml, the following percentage of dishes with type II or III foci were observed: B[j]A, 59%; B[j]A-diol-epoxide, 75%; B[j]A-1,2-oxide, 25%; and B[j]A-9,10-diol, 17%. DNA adducts of B[j]A, B[j]A-9,10-diol, B[j]A-diol-epoxide, B[j]A-9,10-oxide, and B[j]A-1,2-oxide in C3H10T1/2 cells were isolated, separated, identified, and quantitated using the 32P-postlabeling method. B[j]A forms two major groups of adducts: one group of adducts is the result of the interaction of B[j]A-1,2-oxide with 2'-deoxyguanosine and 2'-deoxyadenosine; the second group of adducts is a result of the interaction of B[j]A-diol-epoxide with 2'-deoxyguanosine and 2'-deoxyadenosine. Qualitative and quantitative analysis of the postlabeling data suggests that B[j]A is metabolically activated by two distinct routes, the bay-region diol-epoxide route and the cyclopenta-ring oxide route, the former being the most significant.

Relationship of nontraditional sex-role attitudes to severity of women's criminal behavior

This study empirically examined the general hypothesis that the recent rise in aggressive women's criminal behavior is a response to nontraditional self-perceptions of the female sex-role. 50 female inmates were administered the Attitudes Toward Women Scale and the Role Theory Demographic Index. Analysis of scores indicated significant inverse relationships between nontraditional sex-role attitudes held by incarcerated female felons and the relative severity of their prior criminal acts. Findings indicate that the women who viewed themselves as most traditionally “feminine” represented the most violent female offenders.