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.

一种广泛使用的激素替代疗法 (HRT) 配方（仅 2003 年就有约 5700 万张处方） 含有结合的马雌激素马烯雌酮 (EN)、马烯雌酮和 8,9-脱氢雌酮（总计约 54%） 成分），以及内源性雌酮和1713-雌二醇。尽管从长期来看，癌症的风险 乳房和其他激素敏感组织已得到广泛宣传，女性继续使用此 配方是因为与绝经后系统的缓解相关的显着健康益处。 马和内源性雌激素对遗传毒性代谢物的代谢激活已被涉及 与 HRT 相关的癌症病因学。据了解，儿茶酚 4-羟基马萘雌酮 (4-OHEN) 是 所有三种马雌激素中最重要的代谢物，并且它形成不寻常的循环、稳定 体外、大鼠乳腺组织模型系统和人类乳腺组织中的 DNA 加合物。 4-的加合物 DNA中含有胞嘧啶、腺嘌呤和鸟嘌呤的OHEN已被识别，并且每种类型的加合物都是 以四种立体异构形式为特征。如果不通过细胞 DNA 修复机制去除，例如 加合物可能会被 DNA 聚合酶错误地复制，从而导致突变，最终可能导致 到肿瘤的发展。核苷酸切除修复（NER）是主要的修复机制 从人类细胞 DNA 中去除大量加合物，其效率取决于其结构特性 加合物及其在 DNA 结构中引起的扭曲。但目前还没有关于如何 NER 酶可加工 12 种不同的 4-OHEN-DNA 加合物。该项目的目标是确定 这些加合物的不同立体异构形式的构象如何影响效率 它们被人类 NER 酶去除。在目标 1 中，具有单个 4-OHEN-DNA 的位点特异性寡核苷酸 将构建病变。在目标 2 中，将通过高分辨率 NMR 分析它们的结构特征， 计算技术，而在目标 3 中，将使用无细胞评估 DNA 修复的抵抗力 细胞中以及用 4-OHEN 处理的培养物中几种不同类型的细胞中的提取物。 4-OHEN-DNA 加合物对人类细胞中的 DNA 修复具有抵抗力，这一点非常重要，因为该信息 可以帮助 (1) 开发生物标志物来识别面临 HR7 不利影响风险的女性，以及 (2) 刺激新的改良雌激素替代药物的设计，这些药物对核苷酸的耐药性较小 _,DNA加合物水平的切除修复酶，因此作为潜在癌症引发剂的活性较低。

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。

• 发表时间: 2009-06
• 影响因子: 4.1
• 作者: Wang, Zhican;Edirisinghe, Praneeth;Sohn, Johann;Qin, Zhihui;Geacintov, Nicholas E.;Thatcher, Gregory R. J.;Bolton, Judy L.
• 通讯作者: Bolton, Judy L.