EPIPODOPHYLLOTOXIN ASSOCIATED SECONDARY LEUKEMIA

表鬼臼毒素相关的继发性白血病

• 批准号: 2748789
• 负责人: Carolyn A Felix
• 金额: $ 12.53万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-07 至 2000-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2748789
• 关键词: DNA repair; DNA topoisomerases; active sites; acute lymphocytic leukemia; acute myelogenous leukemia; adolescence (12-20); antineoplastics; bone marrow; chemical cleavage; child (0-11); chromosome translocation; computer assisted sequence analysis; drug resistance; enzyme activity; enzyme inhibitors; hematopoietic stem cells; human subject; intermolecular interaction; nucleic acid sequence; pathologic process; polymerase chain reaction; southern blotting; tissue /cell culture

Chromosomal band 11q23 is involved in reciprocal translocations in de novo acute lymphoblastic leukemia and acute myeloid leukemia (AML) of infants and young children and in epipodophyllotoxin-associated secondary AML. Perturbation of the topoisomerase II-DNA interaction by epipodophyllotoxins and resultant double-stranded breaks in DNA are cytotoxic to cancer cells. The DNA topoisomerase II inhibitors interfere specifically with topoisomerase II by stabilizing a covalent enzyme-DNA intermediate. Secondary AML with reciprocal translocations at chromosomal band 11q23 is a well-established epidemiologic consequence of treatment with these drugs. The strong association of secondary AML with chemotherapy targeted to this enzyme leads to the hypothesis that the 11q23 chromosomal breakpoints are related to drug-induced cleavage of the DNA by topoisomerase II. The 11q23 translocations also may reflect attempts at repair of the abnormal cleavage. The objective of this proposal is to bridge the gap between the well-described cause and effect relationship between topoisomerase II inhibitor chemotherapy and secondary AML, and the molecular requirements for translocations specifically involving chromosomal band 11q23. The first aim is to use PCR based methods to clone, sequence, align and compare twenty secondary AML 11q23 genomic breakpoints and the parental for homologues from which they were derived for consistencies either at the breakpoints or nearby that suggest consensus sequences for epipodophyllotoxin-induced topoisomerase II DNA cleavage sites. Examination of parental homologues is essential because the translocations may cause alterations in the normal sequence. The second aim is to use in vitro topoisomerase II DNA cleavage assays to investigate drug-stabilized topoisomerase II cleavage of parental DNAs at sites predicted by the sequencing of secondary AML genomic breakpoints. The third aim is to study epipodophyllotoxin-induced topoisomerase II DNA cleavage in the parental homologues of 11q23 genomic breakpoint sequences in human hematopoietic cells in tissue culture. Since perinatal toxic exposures are associated with leukemia in infants, the final aim is to clone, sequence and align twenty de novo 11q23 leukemia translocation breakpoints and their parental homologues to investigate the specificity of the mechanism for the secondary cases. Because epipodophyllotoxins are highly effective in many cancers of children and adults, the frequency of topoisomerase II inhibitor-associated secondary AML has increased. The combined analyses of 11q23 leukemia genomic breakpoint sequences from patients exposed to topoisomerase Il inhibitors, and DNA exposed to topoisomerase Il inhibitors in vitro and in tissue culture will establish the relationship between DNA topoisomerase II and the translocation breakpoints. Study of these leukemias provides a unique opportunity to link etiology and pathogenesis.

染色体带11q23参与从头互相易位 婴儿的急性淋巴细胞白血病和急性髓样白血病（AML） 和幼儿以及与植物毒素相关的次级AML。 拓扑异构酶II-DNA相互作用的扰动 DNA中的附生植物毒素和由此产生的双链断裂为 细胞毒性对癌细胞。 DNA拓扑异构酶II抑制剂干扰 特别使用拓扑异构酶II，通过稳定共价酶-DNA 中间的。染色体上的次级AML与互惠易位 Band 11Q23是公认的流行病学结果 使用这些药物。二级AML与 针对这种酶的化学疗法导致了以下假设 11q23染色体断点与药物诱导的裂解有关 拓扑异构酶II的DNA。 11q23易位也可能反映 尝试修复异常裂解的尝试。这个目的 提案是弥合描述良好的因果关系之间的差距 拓扑异构酶II抑制剂化学疗法与继发性的关系 AML，以及特别易位的分子要求 涉及染色体带11Q23。第一个目的是使用基于PCR 克隆，序列，对齐和比较二十个次级AML 11q23的方法 基因组断点和同源物的父母 在断点或附近的一致性中得出 附属毒素诱导的拓扑异构酶II DNA的共识序列 切割站点。对父母同源物的检查至关重要，因为 易位可能导致正常序列的改变。这 第二个目的是使用体外拓扑异构酶II DNA裂解测定到 研究父母DNA的药物稳定的拓扑异构酶II裂解 次级AML基因组断裂点测序预测的位点。 第三个目的是研究附生噬蛋白毒素诱导的拓扑异构酶II DNA 11q23基因组断点序列的父母同源物中的裂解 在组织培养的人类造血细胞中。由于围产期有毒 暴露与婴儿白血病有关，最终目的是 克隆，序列和对齐二十二十一季度11q23白血病易位 断点及其父母的同源物来研究特异性 次要情况的机制。因为附生噬蛋白是 在许多儿童和成人的癌症中非常有效， 拓扑异构酶II抑制剂相关的二级AML增加。这 11q23白血病基因组断点序列的联合分析来自 暴露于拓扑异构酶IL抑制剂的患者，DNA暴露于 拓扑异构酶IL体外和组织培养中的抑制剂将建立 DNA拓扑异构酶II与易位之间的关系 断点。这些白血病的研究为 连接病因和发病机理。