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: 10079499
• 负责人: NEIL OSHEROFF
• 金额: $ 30.22万
• 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 2021-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10079499
• 关键词: 11q23; Acute Myelocytic Leukemia; Acute Promyelocytic Leukemia; Affect; Antineoplastic Agents; Apoptosis; Bypass; Cancer Patient; Catalytic DNA; Cell Death; Cell Survival; Cells; Chemotherapy-Oncologic Procedure; Chromatids; Chromosomal translocation; Chromosome 15; Chromosome Band; Chromosome Segregation; Chromosome Structures; Cleaved cell; Complex; Coupled; Cultured Cells; DNA; DNA Damage; DNA Double Strand Break; DNA Topoisomerase IV; DNA biosynthesis; DNA topoisomerase II alpha; Daughter; Development; Drug Prescriptions; Drug Targeting; Enzymes; Epirubicin; Etoposide; Exposure to; Generations; Genetic Materials; Genetic Recombination; Genetic Transcription; Genomics; Geometry; Handedness; Human; In Vitro; Infant; Lead; Learning; MLL gene; Magnetism; Malignant Neoplasms; Maternal Exposure; Mediating; Mitosis; Mitoxantrone; Natural Product Drug; Natural Products; Neonatal Leukemia; Neurofibrillary Tangles; Oligonucleotides; Pathway interactions; Pharmaceutical Preparations; Phase; Physiological; Play; Poison; Polyamines; Pregnancy; Proliferating; Protein Isoforms; Quinones; Reaction; Research; Research Design; Risk; Role; Site; Study models; Techniques; Text; Time; Topoisomerase; Topoisomerase II; Topoisomerase Interaction; Toxin; Vertebrates; Work; Xenopus laevis; cancer cell; cell growth; cell killing; design; dietary; drug action; drug development; egg; experimental study; genome integrity; innovation; leukemia; leukemogenesis; mutant; neuron development; novel; novel therapeutics; single molecule; targeted agent

Enter the text here that is the new abstract information for your application. This section must be no longer than 30 lines of text. 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, evidence suggests that they also have the potential to trigger specific leukemias. A small percentage of cancer (and other) patients treated with topoisomerase II-targeted drugs eventually develop acute myeloid leukemias (AMLs) involving the MLL gene at chromosome band 11q23 or acute promyelocytic leukemias involving 15:17 translocations. The 11q23 chromosomal translocations also are seen in infant AMLs, and the risk of these leukemias rises ~3–fold when there is high maternal exposure during pregnancy to environmental and dietary topoisomerase II poisons. Despite the importance of type II topoisomerases to cell growth and cancer, we still have much to learn about how the human enzymes function and interact with DNA and anticancer drugs in vitro, in cells, and in vertebrate animals. Thus, the proposed aims are designed to further define the catalytic mechanism and DNA interactions of topoisomerase II and assess the mechanism by which novel topoisomerase II-targeted drugs and drug-DNA conjugates increase levels of enzyme-mediated DNA breaks in vitro, in cultured cells, and in vertebrate animals. The primary research models for this study will be human topoisomerase IIα and IIβ, cultured human cells, and Xenopus laevis extracts. Bacterial gyrase and topoisomerase IV also will be used to assess relationships between the mechanisms of action of drugs targeted to prokaryotic and eukaryotic type II enzymes.

在此处输入文本，该文本是您的应用程序的新摘要信息。此部分的文本长度不得超过 30 行。 II 型拓扑异构酶是普遍存在的酶，是正确的染色体结构和分离所必需的，并且在 DNA 复制、转录和重组中发挥重要作用。这些酶通过在单独的 DNA 片段（门片段）中产生的短暂双链断裂传递完整的双螺旋（运输片段），从而放松 DNA 并消除遗传物质中的结和缠结。人类编码两种密切相关的 II 型酶亚型：拓扑异构酶 IIα 和拓扑异构酶 IIβ。拓扑异构酶 IIα 对于增殖细胞的生存至关重要，而拓扑异构酶 IIβ 在发育过程中发挥着关键作用。然而，由于这些酶在其关键催化功能期间产生必要的双链 DNA 断裂，因此它们呈现出双重角色。尽管它们对细胞生存至关重要，但它们每次发挥作用时也会对基因组完整性构成内在威胁。 除了其关键的生理功能之外，拓扑异构酶 IIα 和 IIβ 是目前用于治疗人类癌症的一些最活跃和最广泛处方药物的主要靶标。这些试剂通过稳定共价拓扑异构酶 II 切割的 DNA 复合物（切割复合物）来杀死细胞，这些复合物是催化 DNA 链通过反应中正常但短暂的中间体。当产生的与酶相关的 DNA 断裂达到足够的浓度时，它们可以触发细胞死亡途径。针对 II 型酶的抗癌药物被称为 II 型拓扑异构酶毒物，因为它们将这些不可或缺的酶转化为强效生理毒素，从而在治疗细胞中产生 DNA 损伤。 尽管拓扑异构酶 IIα 和 IIβ 是癌症化疗的重要靶点，但有证据表明它们也有可能引发特定的白血病。使用拓扑异构酶 II 靶向药物治疗的一小部分癌症（和其他）患者最终会发展为涉及 11q23 染色体带 MLL 基因的急性髓系白血病 (AML) 或涉及 15:17 易位的急性早幼粒细胞白血病。 11q23 染色体易位也见于婴儿 AML，当母亲在怀孕期间大量接触环境和饮食拓扑异构酶 II 毒物时，这些白血病的风险会增加约 3 倍。 尽管 II 型拓扑异构酶对细胞生长和癌症很重要，但关于人类酶如何在体外、细胞和脊椎动物中发挥作用以及与 DNA 和抗癌药物相互作用，我们还有很多东西需要了解。因此，所提出的目标旨在进一步明确拓扑异构酶 II 的催化机制和 DNA 相互作用，并评估新型拓扑异构酶 II 靶向药物和药物-DNA 缀合物在体外、培养细胞和脊椎动物中增加酶介导的 DNA 断裂水平的机制。本研究的主要研究模型将是人类拓扑异构酶 IIα 和 IIβ、培养的人类细胞和非洲爪蟾提取物。细菌旋转酶和拓扑异构酶 IV 还将用于评估针对原核和真核 II 型酶的药物作用机制之间的关系。