Nesnow S, Ross J, Mohapatra N, Gold A, Sangaiah R, Gupta R
Carcinogenesis and Metabolism Branch, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711.
Mutat Res. 1989 Mar;222(3):223-35. doi: 10.1016/0165-1218(89)90138-9.
Aceanthrylene (ACE), a cyclopenta-fused polycyclic aromatic hydrocarbon (CP-PAH) related to anthracene, has been studied for its ability to be metabolized, to form DNA adducts, and to morphologically transform C3H10T1/2CL8 mouse embryo fibroblasts in culture. Although ACE has been previously shown to be a strong mutagen in Salmonella typhimurium strains TA89 and TA100, it did not transform C3H10T1/2 cells (0.4-16 micrograms/ml) under 2 treatment protocols: treatment (for 24 h) 1 day after seeding the cells; treatment (for 24 h) 5 days after seeding the cells. Both protocols are effective in detecting the morphological transforming activity of PAH and CP-PAH and the latter protocol has been shown to be effective in detecting chemicals which are active in the first protocol only with the additional treatment of the cells with a tumor promoter. ACE is metabolized by C3H10T1/2 cells to ACE-1,2-dihydrodiol (the cyclopenta-ring dihydrodiol) at a rate of 450 pmoles ACE-1,2-dihydrodiol formed/h/10(6) cells. ACE-7,8-dihydrodiol and ACE-9,10-dihydrodiol, identified as major Aroclor-1254-induced rat liver microsomal metabolites from their UV, NMR, and mass spectral data, were not identified in incubations of C3H10T1/2 cells with ACE. ACE-DNA adducts in C3H10T1/2 cells were isolated, separated, identified, and quantitated using the 32P-postlabeling method. ACE forms 4 major adducts and each was identified as an ACE-1,2-oxide/2'-deoxyguanosine adduct. The level of adduction was 2.18 pmoles ACE adducts/mg DNA after a 24-h incubation of ACE (16 micrograms/ml) with C3H10T1/2 cells. ACE-DNA adduct persistence and repair were evaluated in C3H10T1/2 cells using a hydroxyurea block after ACE treatment. ACE-DNA adducts were not repaired under the conditions used in the morphological transformation studies. Thus, ACE provides an interesting example of a mutagenic PAH which is metabolized by C3H10T1/2 cells to active intermediates, forms relatively stable and persistent 2'-deoxyguanosine adducts in C3H10T1/2 cells, and yet induces no detectable morphological transforming activity under the experimental conditions used.
苊烯（ACE）是一种与蒽相关的环戊稠合多环芳烃（CP-PAH），人们已对其代谢能力、形成DNA加合物的能力以及在培养中使C3H10T1/2CL8小鼠胚胎成纤维细胞发生形态转化的能力进行了研究。尽管ACE先前已被证明是鼠伤寒沙门氏菌TA89和TA100菌株中的强诱变剂，但在两种处理方案下，它都未使C3H10T1/2细胞发生转化（0.4 - 16微克/毫升）：在细胞接种后1天进行处理（24小时）；在细胞接种后5天进行处理（24小时）。这两种方案在检测PAH和CP-PAH的形态转化活性方面都是有效的，并且已证明后一种方案在检测仅在第一种方案中通过用肿瘤启动剂对细胞进行额外处理才具有活性的化学物质方面是有效的。ACE被C3H10T1/2细胞代谢为ACE - 1,2 - 二氢二醇（环戊环二氢二醇），形成速率为450皮摩尔ACE - 1,2 - 二氢二醇/小时/10⁶个细胞。根据其紫外、核磁共振和质谱数据被鉴定为主要的多氯联苯混合物Aroclor - 1254诱导的大鼠肝微粒体代谢物的ACE - 7,8 - 二氢二醇和ACE - 9,10 - 二氢二醇，在C3H10T1/2细胞与ACE的孵育中未被鉴定出来。使用³²P后标记法对C3H10T1/2细胞中的ACE - DNA加合物进行了分离、鉴定和定量。ACE形成4种主要加合物，每种加合物都被鉴定为ACE - 1,2 - 氧化物/2'-脱氧鸟苷加合物。在ACE（16微克/毫升）与C3H10T1/2细胞孵育24小时后，加合水平为2.18皮摩尔ACE加合物/毫克DNA。在ACE处理后，使用羟基脲阻断法在C3H10T1/2细胞中评估了ACE - DNA加合物的持久性和修复情况。在形态转化研究中使用的条件下，ACE - DNA加合物未被修复。因此，ACE提供了一个有趣的诱变PAH的例子，它被C3H10T1/2细胞代谢为活性中间体，在C3H10T1/2细胞中形成相对稳定和持久的2'-脱氧鸟苷加合物，但在所用的实验条件下未诱导出可检测到的形态转化活性。
