BIOLOGICAL SIGNIFICANCE OF PAH AND ESTROGEN-DNA ADDUCTS

PAH 和雌激素-DNA 加合物的生物学意义

• 批准号: 6344724
• 负责人: ELEANOR G ROGAN
• 金额: $ 16.87万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-05-01 至 2001-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6344724
• 关键词: DNA damage; adduct; animal genetic material tag; carbopolycyclic compound; chemical carcinogenesis; cutaneous papilloma; estrogens; gene mutation; genetic mapping; oncogenes; polymerase chain reaction; tissue /cell culture

The goal on this project is to understand the relationship between carcinogen-DNA adducts, oncogenic mutations and initiation of cancer by polycyclic aromatic hydrocarbons (PAH) and catechol estrogens (CE). We have established a relationship between depurinating DNA adducts, which are released from DNA to leave apurinic sites, and the Harvey (h)-ras mutations exhibited by mouse skin papillomas induced by benzo[alpha]pyrene (BP), dibenzo[alpha,l)pyrene(DB[alpha,l]P), 7,12-dimethylbenz[alpha]anthracene (DMBA) and some of their metabolites. Specifically, depurinating adducts of Ade lead to A yields T transversions at codon 61 in ras and depurinating Gua adducts lead to G yields T transversions in codon 13. Presumably, the mutations are a consequence of mis-repaired apurinic sites generated by the loss of the depurinating adducts. Endogenous CE, metabolites of estrone (E1) and 17beta-estradiol (E2) that we hypothesize to be procarcinogens, can be oxidized to CE quinones (CE-Q) and bind to DNA. CE-3,4-Q form depurinating N7Gua adducts in abundance, generating apurinic sites in the DNA, which in vivo could be misrepaired to yield oncogenic mutations. To gain further evidence that H-ras mutations arise from depurinating adducts formed by PAH and CE-Q and to increase our understanding of sequence specificity in the formation of stable adducts and apurinic sits, we propose to (1) determine the H-ras mutations in mouse skin papillomas induced by selected PAH and correlate the mutations with adducts; (2) investigate whether H-ras mutations can be detected in preneoplastic mouse skin treated with DB[alpha l)P or DB[alphal]P-11,12-dihydrodiol; (3) analyze the stable and depurinating adducts formed in 18-bp oligonucleotides by treatment with CE-Q; (4) identify the nature of the DNA lesions (i.e., stable adducts or apurinic sites) in (a) a 231 base-pair region of pBR322 DFNA and (b) the exon 1 and 2 region (547 base-pairs) of c-H-ras induced by treatment with BPDE, DB[alphal]PDE, CE-Q or peroxidase- activated BP, DB[alpha,l]P or CE; and (5) analyze the mutations induced in the supF gene replicated by a HeLa cell extract after treatment with BPDE, DB[alpha,l]PDE, CE-Q or peroxidase-activated BP, DB[alpha,l]P or CE. The results of these studies will provide us with detailed knowledge of the reaction of the selected PAH and CE-Q with DNA to generate apurinic sites, stable adducts and oncogenic mutations.

该项目的目标是了解之间的关系 致癌物-DNA 加合物、致癌突变和癌症起始 多环芳烃（PAH）和儿茶酚雌激素（CE）。 我们 已经建立了脱嘌呤DNA加合物之间的关系，它们是 从 DNA 中释放以留下无嘌呤位点，以及 Harvey (h)-ras 突变 由苯并芘(BP)诱导的小鼠皮肤乳头状瘤表现出， 二苯并[α,l]芘(DB[α,l]P), 7,12-二甲基苯并[α]蒽 （DMBA）及其一些代谢物。 具体来说，脱嘌呤加合物 Ade 导致 A 在 ras 密码子 61 处产生 T 颠换并脱嘌呤 Gua 加合物导致 G 产生密码子 13 中的 T 颠换。 突变是由错误修复的无嘌呤位点产生的结果 脱嘌呤加合物的损失。 内源性CE，雌酮代谢物 (E1) 和 17β-雌二醇 (E2)，我们假设它们是致癌物质， 可以被氧化成 CE 醌 (CE-Q) 并与 DNA 结合。 CE-3,4-Q形式 大量脱嘌呤 N7Gua 加合物，在 DNA，在体内可能被错误修复而产生致癌突变。 到 获得进一步的证据表明 H-ras 突变是由脱嘌呤加合物引起的 由 PAH 和 CE-Q 形成并增加我们对序列的理解 稳定加合物和无嘌呤位点形成的特异性，我们 建议（1）确定小鼠皮肤乳头状瘤中的H-ras突变 由选定的 PAH 诱导并将突变与加合物相关联； (2) 研究是否可以在肿瘤前期小鼠中检测到 H-ras 突变 用DBα1P或DBαP-11，12-二氢二醇处理的皮肤； (3) 分析 18-bp 中形成的稳定和脱嘌呤加合物 通过CE-Q处理寡核苷酸； (4)鉴定DNA的性质 (a) 231 个碱基对中的损伤（即稳定加合物或无嘌呤位点） pBR322 DFNA 区域和 (b) 外显子 1 和 2 区域（547 个碱基对） 通过用 BPDE、DBαPDE、CE-Q 或过氧化物酶处理诱导的 c-H-ras 活化的 BP、DB[α,l]P 或 CE； (5) 分析诱导的突变 用 BPDE 处理后 HeLa 细胞提取物复制的 suF 基因， DB[α,1]PDE、CE-Q 或过氧化物酶激活的 BP、DB[α,1]P 或 CE。 这 这些研究的结果将为我们提供详细的知识 选定的 PAH 和 CE-Q 与 DNA 反应生成无嘌呤位点， 稳定加合物和致癌突变。