Isomeric HRT estrogen-DNA adducts: Structure and Repair

异构 HRT 雌激素-DNA 加合物：结构和修复

• 批准号: 7740928
• 负责人: Nicholas E Geacintov
• 金额: $ 5.2万
• 依托单位: NEW YORK UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7740928
• 关键词: 4-hydroxy-equilenin; Adenine; Adverse effects; Affect; Base Sequence; Biological Markers; Biological Models; Breast Cancer Cell; Cancer Etiology; Cancer cell line; Catechols; Cell Line; Cells; Characteristics; Computational Technique; Computing Methodologies; Conjugated Equine Estrogens; Cultured Cells; Cytosine; DNA; DNA Adducts; DNA Repair; DNA Repair Enzymes; DNA Structure; DNA lesion; DNA-Directed DNA Polymerase; Data; Development; Drug Formulations; Equilenin; Equilin; Equus caballus; Estradiol; Estrogen Replacements; Estrogens; Estrone; Excision; Goals; Guanine; Health Benefit; Hormone replacement therapy; Hormones; Human; In Vitro; Kinetics; Lead; Lesion; Malignant Neoplasms; Mammary Gland Parenchyma; Mammary gland; Metabolic Activation; Methods; Molecular Conformation; Mutation; Nucleotide Excision Repair; Nucleotides; Oligodeoxyribonucleotides; Oligonucleotides; Pattern; Pharmaceutical Preparations; Postmenopause; Predisposition; Process; Property; Rattus; Relative (related person); Resistance; Resolution; Risk; Site; Structure; System; Testing; Time; Tissue Model; Tissues; Woman; adduct; base; cancer risk; cell type; design; insight; malignant breast neoplasm; repair enzyme; repaired; tumor

A widely used hormone replacement therapy (HRT) formulation (~ 57 million prescriptions in 2003 alone) contains the conjugated equine estrogens equilenin (EN), equilin, and 8,9-dehydro-estrone (total ~ 54% composition), and the endogenous estrone and 1713-estradiol. Although the long term risks of cancers of the breast and other hormone-sensitive tissues have been well publicized, women continue to use this formulation because of the significant health benefits associated with the relief of post-menopausal systems. The metabolic activation of equine and endogenous estrogens to genotoxic metabolites has been implicated in the etiology of cancers associated with HRT. It is known that the catechol 4-hydroxyequilenin (4-OHEN) is the most significant metabolite among all three equine estrogens, and that it forms unusual cyclic, stable DNA adducts in vitro, in rat mammary tissue model systems, and in human breast tissue. Adducts of 4- OHEN with cytosine, adenine, and guanine in DNA have been recognized, and each type of adduct is characterized by four stereoisomedc forms. If not removed by cellular DNA repair mechanisms, such adducts may be incorrectly replicated by DNA polymerases, thus causing mutations that may ultimately lead to the development of tumors. Nucleotide excision repair (NER) is the major repair mechanisms that removes bulky adducts from DNA in human cells with efficiencies that depend on the structural properties of the adducts and the distortions they cause in the DNA structure. However, there is no information on how the 12 different 4-OHEN-DNA adducts are processed by NER enzymes. The goal of this project is to determine how the conformations of the different stereoisomeric forms of these adducts influence the efficiencies of their removal by human NER enzymes. In aim 1, site-specific oligonucleotides with single 4-OHEN-DNA lesions will be constructed. In aim 2, their structural features will be analyzed by high resolution NMR and computational techniques, while in aim 3, the resistance to DNA repair will be evaluated using cell free extracts in cells, and in several different types of cells in culture treated with 4-OHEN.The identification of the 4-OHEN-DNA adducts that are resistant to DNA repair in human cells is significant because this information could help to (1) develop biomarkers for identifying women at risk to the adverse effects of HR7, and (2) stimulate the design of new, modified estrogen replacement drugs that are less resistant to nucleotide _,xcision repair enzymes at the DNA adduct level, and thus less active as potential cancer initiating agents.

广泛使用的激素替代疗法（HRT）制剂（仅在2003年就有5700万处方） 包含共轭的马雌激素平衡（EN），Equilin和8,9-脱氧雌激素（总计约54％） 组成），内源性雌酮和1713-雌二醇。尽管长期癌症的长期风险 乳房和其他对激素敏感的组织已经很好地宣传，妇女继续使用 由于与绝经后系统的缓解相关的健康益处，因此制定了良好的健康益处。 马和内源性雌激素对遗传毒性代谢产物的代谢激活已与 在与HRT相关的癌症的病因中。众所周知，Catechol 4-羟基均等宁（4-OHEN）是 在所有三种马雌激素中，最重要的代谢产物，它形成不寻常的循环，稳定 大鼠乳腺组织模型系统中的DNA加合物在体外和人类乳房组织中。 4-加合物 识别DNA中的胞嘧啶，腺嘌呤和鸟嘌呤的OHEN已被识别，每种类型的加合物均为 以四种立体声形式为特征。如果不通过细胞DNA修复机制去除，则 加合物可能会被DNA聚合酶错误地复制，从而导致突变可能最终导致 肿瘤的发展。核苷酸切除修复（NER）是主要的修复机制 以效率取决于人类细胞中DNA的笨重加合物的效率取决于 它们在DNA结构中引起的加合物及其扭曲。但是，没有关于如何 NER酶处理12种不同的4-OHEN-DNA加合物。该项目的目的是确定 这些加合物的不同立体异构形式的构象如何影响 它们被人类NER酶去除。在AIM 1中，具有单个4-OHEN-DNA的位点特异性寡核苷酸 病变将被建造。在AIM 2中，将通过高分辨率NMR分析它们的结构特征和 计算技术，而在AIM 3中，将使用无细胞来评估对DNA修复的阻力 细胞中的提取物，在用4-OHEN处理的培养物中的几种不同类型的细胞中。 4-OHEN-DNA加合物在人类细胞中对DNA修复具有抗性很重要，因为此信息 可以帮助（1）开发生物标志物，以确定对HR7不利影响的妇女，以及（2） 刺激新的，改良的雌激素替代药物的设计，这些药物对核苷酸的耐药性较低 _，在DNA加合物水平上的Xcision修复酶，因此作为潜在癌症启动剂的活性较低。

项目成果

Development of a liquid chromatography electrospray ionization tandem mass spectrometry method for analysis of stable 4-hydroxyequilenin-DNA adducts in human breast cancer cells.

开发用于分析人乳腺癌细胞中稳定的 4-羟基马萘醌-DNA 加合物的液相色谱电喷雾电离串联质谱方法。

• DOI: 10.1021/tx900063g
• 发表时间: 2009
• 期刊: Chemical research in toxicology
• 影响因子: 4.1
• 作者: Wang,Zhican;Edirisinghe,Praneeth;Sohn,Johann;Qin,Zhihui;Geacintov,NicholasE;Thatcher,GregoryRJ;Bolton,JudyL
• 通讯作者: Bolton,JudyL