Metabolism of benzo[a]pyrene by human mammary epithelial cells: toxicity and DNA adduct formation.
Metabolism of benzo[a]pyrene by human mammary epithelial cells: toxicity and DNA adduct formation.
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DOI：
10.1073/pnas.78.10.6251
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发表时间：
1981-10
影响因子：
11.1
通讯作者：
M. Stampfer;J. Bartholomew;H. Smith;J. Bartley
中科院分区：
文献类型：
--
作者：
M. Stampfer;J. Bartholomew;H. Smith;J. Bartley
人乳腺上皮细胞和早期传代的成纤维细胞的纯培养物提供了询问两种细胞类型是否具有代谢化学致癌物的能力的机会，如果是的话，与化学致癌物相容的代谢产物的命运是否是女性乳腺癌发生的一个因素。为此，细胞暴露于苯并[a]芘（BaP），（i）对生长潜力的影响和（ii）BaP和DNA的代谢产物之间的加合物的程度，类型和持久性进行了测量。与成纤维细胞相比，上皮细胞的生长抑制对BaP的敏感性高50-100倍。由于这种不同的敏感性，在DNA加合物形成的研究中，上皮细胞暴露于0.4 μ M BaP，成纤维细胞暴露于4.0 μ M BaP。通过高压液相色谱法从纯化的DNA中分离（+/-）-7，8-二羟基-9，10-环氧-7，8，9，10-四氢苯并[a]芘（BaP二醇环氧化物）和核苷之间的加合物，发现上皮细胞在加入BaP后6小时内含有修饰的DNA。BaP二醇环氧化物和脱氧鸟苷的7 R反立体异构体之间的加合物始终占主导地位。顺式BaP二醇环氧化物与脱氧鸟苷的加合物和似乎是BaP二醇环氧化物与脱氧胞苷的加合物始终存在，但频率低得多。所有三种类型的BaP二醇环氧化物-DNA加合物在上皮细胞中持续72小时，在BaP-无培养基。在成纤维细胞培养物中没有检测到加合物，直到第一次暴露于BaP后96小时。此时，BaP二醇环氧化物-DNA加合物形成的类型和程度与暴露于十分之一剂量的BaP的上皮细胞中的类似。在人类乳腺上皮细胞中的加合物的类型，程度，形成率和持久性是类似的细胞转化暴露于苯并[a]芘，这表明它们可能是化学诱导的致癌作用的目标。
Pure cultures of human breast epithelial cells and of fibroblastic cells in early passage provided the opportunity to ask whether either cell type had the capability for metabolizing chemical carcinogens and, if so, was the fate of the metabolic products compatible with chemical carcinogens being a factor in the initiation of breast cancer in women. For this purpose, cells were exposed to benzo[a]pyrene (BaP), and (i) the influence on growth potential and (ii) the extent, type, and persistence of adducts between the metabolites of BaP and DNA were measured. Compared with fibroblasts, inhibition of growth by epithelial cells was 50-100 times more sensitive to BaP. Because of this differential sensitivity, epithelial cells were exposed to 0.4 microM BaP and fibroblasts were exposed to 4.0 microM BaP in the studies of DNA adduct formation. Separation by high-pressure liquid chromatography of adducts between (+/-)-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BaP diol epoxide) and nucleosides from purified DNA revealed that epithelial cells contained modified DNA within 6 hr after adding BaP. Adducts between the 7R anti stereoisomer of BaP diol epoxide and deoxyguanosine predominated at all times. syn BaP diol epoxide adducts with deoxyguanosine and what appeared to be BaP diol epoxide adducts with deoxycytidine were consistently present but at much lower frequency. All three types of BaP diol epoxide--DNA adducts persisted in epithelial cells for 72 hr in BaP-free medium. No adducts were detected in fibroblastic cultures until 96 hr after first exposure to BaP. At this time, the type and extent of BaP diol epoxide--DNA adduct formation was similar to that in epithelial cells exposed to one-tenth the dose of BaP. The type, extent, rate of formation, and persistence of the adducts in human breast epithelial cells was similar to that in cells transformable by exposure to BaP, an indication that they may be targets for chemically induced carcinogenesis.