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

基本信息

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
项目类别：
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

项目摘要

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.

在此输入您的申请的新摘要信息的文本。此部分的文本长度不得超过 30 行。 II 型拓扑异构酶是适当染色体结构和分离所需的普遍存在的酶，在 DNA 复制、转录和重组中发挥重要作用。这些酶通过传递完整的双螺旋（运输片段）来放松 DNA 并消除遗传物质中的结和缠结。）通过它们在单独的 DNA 片段（门片段）中产生的短暂双链断裂，人类编码了两种密切相关的 II 型酶异构体：拓扑异构酶 IIα 和 II 型。拓扑异构酶 IIβ 对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过程中产生必要的双链 DNA 断裂，因此它们具有双重角色。为了生存，它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，这些药物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。它们是催化 DNA 链传递反应中正常但短暂的中间体，当产生的酶相关 DNA 断裂以足够的浓度存在时，它们可以触发细胞死亡途径。靶向 II 型酶的药物被称为拓扑异构酶 II 毒物，因为它们将这些不可或缺的酶转化为强效生理毒素，在受治疗的细胞中产生 DNA 损伤。尽管拓扑异构酶 IIα 和 IIβ 是癌症化疗的重要靶标，但有证据表明，它们也有可能引发特定的白血病。接受拓扑异构酶 II 靶向药物治疗的癌症（和其他）患者中，有一小部分最终会发展为急性髓系白血病 (AML)。染色体带 11q23 上的 MLL 基因或涉及 15:17 易位的急性早幼粒细胞白血病。婴儿 AML 中也存在染色体易位，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，但我们仍然有很多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的知识。因此，设计了拟议的目标。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、培养的人类细胞以及非洲爪蟾提取物，也将用于评估药物作用机制之间的关系。针对原核和真核 II 型酶。