Mechanistic Studies of Type II Topoisomerases and Topoisomerase-Targeted Agents

II 型拓扑异构酶和拓扑异构酶靶向药物的机理研究

• 批准号: 10533336
• 负责人: NEIL OSHEROFF
• 金额: $ 35.58万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-02-01 至 2025-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10533336
• 关键词: Acute Promyelocytic Leukemia; Affect; Antineoplastic Agents; Apoptosis; Bacillus anthracis; Biological; CDC2 gene; Catalysis; Catalytic DNA; Catenated DNA; Cell Death; Cell Proliferation; Cell Survival; Cells; Chemotherapy-Oncologic Procedure; Chromatids; Chromosomal translocation; Chromosome Segregation; Chromosome Structures; Complex; Cultured Cells; Cyclin B; DNA; DNA Damage; DNA Double Strand Break; DNA Topoisomerase IV; DNA biosynthesis; DNA topoisomerase II alpha; Daughter; Development; Drug Prescriptions; Drug Targeting; Enzyme Inhibition; Enzymes; Escherichia coli; Etoposide; Gene Mutation; Generations; Genetic Materials; Genetic Recombination; Genetic Transcription; Geometry; Handedness; Herb; Human; Human Activities; Impairment; In Vitro; Learning; MLL gene; Magnetism; Malignant Neoplasms; Mechanical Stress; Mediating; Medicine; Mitosis; Mitoxantrone; Multiple Sclerosis; Mycobacterium tuberculosis; Naphthoquinones; Natural Products; Neurofibrillary Tangles; PML gene; Pathway interactions; Patients; Pharmaceutical Preparations; Physiological; Play; Poison; Property; Protein Isoforms; Reaction; Regulation; Relaxation; Research; Research Design; Role; Specificity; Study models; Techniques; Time; Topoisomerase; Topoisomerase II; Topoisomerase Inhibitors; Toxin; Type I DNA Topoisomerases; Xenopus laevis; anti-cancer; cell growth; cell killing; drug action; drug development; egg; environmental chemical; enzyme activity; experimental study; genome integrity; in vitro activity; inhibitor; innovation; leukemia; neuron development; novel; novel therapeutics; pollutant; single molecule; targeted agent

Type II topoisomerases are ubiquitous enzymes that are required for proper chromosome structure and segregation and play important roles in DNA replication, transcription, and recombination. These enzymes relax DNA and remove knots and tangles from the genetic material by passing an intact double helix (transport segment) through a transient double-stranded break that they generate in a separate DNA segment (gate segment). Humans encode two closely related isoforms of the type II enzyme, topoisomerase IIα and topoisomerase IIβ. Topoisomerase IIα is essential for the survival of proliferating cells and topoisomerase IIβ plays critical roles during development. However, because these enzymes generate requisite double-stranded DNA breaks during their crucial catalytic functions, they assume a dual persona. Although essential to cell survival, they also pose an intrinsic threat to genomic integrity every time they act. Beyond their critical physiological functions, topoisomerase IIα and IIβ are the primary targets for some of the most active and widely prescribed drugs currently used for the treatment of human cancers. These agents kill cells by stabilizing covalent topoisomerase II-cleaved DNA complexes (cleavage complexes) that are normal, but fleeting, intermediates in the catalytic DNA strand passage reaction. When the resulting enzyme- associated DNA breaks are present in sufficient concentrations, they can trigger cell death pathways. Anticancer drugs that target type II enzymes are referred to as topoisomerase II poisons because they convert these indispensable enzymes to potent physiological toxins that generate DNA damage in treated cells. Although topoisomerase IIα and IIβ are important targets for cancer chemotherapy, they also have the potential to trigger specific leukemias. For example, a small percentage of patients with cancer or multiple sclerosis who are treated with the topoisomerase II-targeted drug mitoxantrone go on to develop acute promyelocytic leukemias (APLs) with 15:17 translocations. Despite the importance of type II topoisomerases in cell growth and cancer, we still have much to learn about how the human enzymes function and interact with DNA and anticancer drugs. Thus, this proposal will further define the catalytic mechanism of type II topoisomerases and examine how enzyme activity is regulated in the cell. It also will define mechanisms by which established and novel topoisomerase II-targeted agents, environ- mental chemicals, and natural products increase levels of enzyme-mediated DNA breaks or inhibit enzyme activity and determine the cellular consequences of topoisomerase II poisons. The primary research models for this study will be human topoisomerase IIα and IIβ, cultured human cells, and Xenopus laevis egg extracts. Gyrase and topoisomerase IV from Escherichia coli and Bacillus anthracis will be used as counterpoints to mechanistic experiments and Mycobacterium tuberculosis gyrase will be used to assess relationships between the mechanisms of action of drugs targeted to prokaryotic and eukaryotic type II enzymes.

II型拓扑异构酶是适当的染色体结构所需的无处不在的酶 隔离和在DNA复制，转录和重组中起重要作用。这些酶 放松DNA，并通过完整的双螺旋（传输 段）通过它们在单独的DNA段中产生的瞬态双链断裂（栅极） 部分）。人类编码II型酶，拓扑异构酶IIα和 拓扑异构酶IIβ。拓扑异构酶IIα对于增殖细胞和拓扑异构酶IIβ的存活至关重要 在开发过程中起关键作用。但是，因为这些酶产生必要的双链 DNA在其关键催化功能期间断裂，它们具有双重角色。虽然对细胞必不可少 生存，他们每次行动都会对基因组完整性构成内在威胁。 除了其关键的生理功能，拓扑异构酶IIα和IIβ是某些的主要目标 目前用于治疗人类癌症的最活跃和规定的药物。这些代理 通过稳定共价拓扑异构酶II裂解的DNA复合物（切割配合物）来杀死细胞 正常但转瞬即逝的中间体在催化DNA链条反应中。当产生的酶 相关的DNA断裂以足够的浓度存在，它们可以触发细胞死亡途径。 靶向II型酶的抗癌药物被称为拓扑异构酶II毒药，因为它们转化了 这些必不可少的酶是潜在的生理毒素，这些生理毒素会在处理的细胞中产生DNA损伤。 尽管拓扑异构酶IIα和IIβ是癌症化疗的重要靶标，但它们也具有 触发特定白血病的潜力。例如，一小部分癌症患者或多个患者 用拓扑异构酶II靶向药物Mitoxantrone治疗的硬化症继续发展急性 有15:17易位的前叶细胞白血病（APLS）。 尽管II型拓扑异构酶在细胞生长和癌症中的重要性，但我们仍然有很多了解 人酶如何与DNA和抗癌药物相互作用。那将进一步 定义II型拓扑异构酶的催化机制，并检查如何调节酶活性 细胞。它还将定义建立和新颖的拓扑异构酶II靶向剂的机制，环境 精神化学物质和天然产物增加酶介导的DNA断裂或抑制酶的水平 活性并确定拓扑异构酶II毒物的细胞后果。主要的研究模型 这项研究将是人拓扑异构酶IIα和IIβ，培养的人类细胞和爪蟾卵卵提取物。 来自大肠杆菌和炭疽芽孢杆菌的回旋酶和拓扑异构酶IV将用作对立点 机械实验和结核分枝杆菌回旋酶将用于评估之间的关系 针对原核和真核II型酶的药物作用机理。