Differential mutagenicity and cytotoxicity of (+/-)-benzo[a]pyrene-trans-7,8-dihydrodiol and (+/-)-anti-benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide in genetically engineered human fibroblasts.
Differential mutagenicity and cytotoxicity of (+/-)-benzo[a]pyrene-trans-7,8-dihydrodiol and (+/-)-anti-benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide in genetically engineered human fibroblasts.
复制标题
(i-)-苯并[a]芘-反式-7,8-二氢二醇和(i-)-抗苯并[a]芘-反式-7,8-二氢二醇-9,10-环氧化物的差异致突变性和细胞毒性
DOI：
10.1002/mc.2940120206
复制
发表时间：
1995
影响因子：
4.6
通讯作者：
States,JC
中科院分区：
文献类型：
--
作者：
Quan,T;ReinersJr,JJ;Culp,SJ;Richter,P;States,JC
DNA 修复缺陷型（A 组着色性干皮病 (XPA)）和 DNA 修复型（正常）人类皮肤成纤维细胞通过可控人细胞色素 P450 (CYP)1A1 表达载体转化进行基因工程改造。 CYP1A1 的诱导使这些细胞能够将 (±)-苯并[a]芘-反式-7,8-二氢二醇 (BPD) 代谢为有效的细胞毒剂和诱变剂。 XPA 细胞比正常细胞更容易受到 CYP1A1 代谢的 BPD 和外源提供的 (±)-抗苯并[a]芘-反式-7,8-二氢二醇-9, 10-环氧化物 (BPDE) 的细胞毒性作用。此外，CYP1A1 代谢的 BPD 诱导的 XPA 和正常细胞之间的差异细胞毒性比外源提供的 BPDE 诱导的细胞毒性高 8.4 倍。这两种细胞系具有相似的 CYP1A1 活性，表明代谢潜力的差异并不是对 BPD 反应差异的原因。在 XPA 和正常细胞中具有相当的细胞毒性时，BPD 处理比 BPDE 处理诱导更多的突变体和更多的 DNA 加合物。在 XPA 细胞中 DNA 加合物水平相似的情况下，CYP1A1 代谢的 BPD 和外源提供的 BPDE 诱导的细胞毒性水平相似，但 CYP1A1 代谢的 BPD 诱导的次黄嘌呤磷酸核糖基转移酶突变频率高出三倍。相比之下，在表达 CYP1A1 的正常细胞中加合物水平相似时，BPD 诱导的细胞毒性较小，突变频率也较低。 DNA 加合物通过 32 P 标记后分析进行鉴定和定量。 CYP1A1代谢的BPD和外源提供的BPDE形成的主要加合物是10-β-(脱氧鸟苷-N2-基)-7β,8α,9α-三羟基-7,8,9,10-四氢苯并[a]芘，表明BPD和BPDE诱导的加合物的差异效应并不是由于形成的加合物类型的差异所致。这些研究的结果表明，CYP1A1 代谢的 BPD 可能优先在转录活性基因中形成加合物，或者 BPDE 的细胞内浓度可能影响细胞毒性和致突变性（或两者）之间的平衡。 © 1995 Wiley-Liss Inc.
DNA repair–deficient (xeroderma pigmentosum group A (XPA)) and DNA repair‐proficient (normal) human skin fibroblasts were genetically engineered by transformation with a controllable human cytochrome P450 (CYP)1A1 expression vector. Induction of CYP1A1 enabled these cells to metabolize (±)‐benzo[a]pyrene‐trans‐7,8‐dihydrodiol (BPD) into a potent cytotoxicant and mutagen. The XPA cells were more susceptible than the normal cells to the cytotoxic effects of both CYP1A1‐metabolized BPD and exogenously supplied (±)‐antibenzo[a]pyrene‐trans‐7,8‐dihydrodiol‐9, 10‐epoxide (BPDE). Furthermore, the differential cytotoxicity between XPA and normal cells induced by CYP1A1‐metabolized BPD was 8.4‐fold greater than that induced by exogenously supplied BPDE. The two cell lines had similar CYP1A1 activities, suggesting that a difference in metabolic potential was not the cause of the differential response to BPD. At comparable cytotoxicity in both XPA and normal cells, BPD treatment induced more mutants and more DNA adducts than BPDE treatment did. At similar levels of DNA adducts in XPA cells, the levels of cytotoxicity induced by CYP1A1‐metabolized BPD and exogenously supplied BPDE were similar, but CYP1A1‐metabolized BPD induced a threefold higher hypoxanthine phosphoribosyltransferase mutation frequency. In contrast, at similar levels of adducts in CYP1A1‐expressing normal cells, BPD induced less cytotoxicity and a lower mutation frequency. DNA adducts were identified and quantified by32P‐postlabeling analyses. The principal adduct formed by both CYP1A1‐metabolized BPD and exogenously supplied BPDE was 10‐β‐(deoxyguanosin‐N2‐yl)‐7β,8α,9α‐trihydroxy‐7,8,9,10‐tetrahydrobenzo[a]pyrene, indicating that the differential effects of BPD‐ and BPDE‐induced adducts were not due to a difference in the types of adducts formed. The results of these studies suggest that CYP1A1‐metabolized BPD may form adducts preferentially in transcriptionally active genes or that the intracellular concentration of BPDE may influence the balance between cytotoxicity and mutagenicity (or both). © 1995 Wiley‐Liss Inc.