Cystathionine B Synthase and ARA C Therapy for Leukemia

胱硫醚 B 合酶和 ARA C 治疗白血病

• 批准号: 6515194
• 负责人: JEFFREY Warren TAUB
• 金额: $ 23.47万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6515194
• 关键词: DNA footprinting; Downs syndrome; Drosophilidae; acute lymphocytic leukemia; acute myelogenous leukemia; antineoplastics; binding sites; clinical research; cystathionine beta synthase; cytosine arabinoside; drug metabolism; enzyme activity; enzyme induction /repression; gel mobility shift assay; gene deletion mutation; human subject; myeloid stem cell; neoplasm /cancer pharmacology; northern blottings; pediatric neoplasm /cancer; polymerase chain reaction; site directed mutagenesis; transcription factor; western blottings

The goal of this project is to better understand the biology of acute myeloid leukemia (AML) in Down syndrome (DS) children related to the association of the chromosome 21-localized gene, cystathionine-beta- synthase (CBS) and response to cytosine arabinoside (ara-C)-based therapy. Childhood AML has the worst prognosis of all major childhood cancers with five year relative survival rates of approximately 37%. In contrast, DS children with AML represent an unique group of leukemia patients in view of having significantly higher event-free survival (EFS) rates (70-100% with relapse rates < 15%) compared to non-DS children when treated with ara-C-based protocols. Thus, identifying the biological basis for the extremely high cure rates of DS AML patients can have very important implications and potentially can lead to improvements in AML therapy for all patients. Our previous results have begun to shed light on the underlying mechanisms responsible for the striking increased EFS in DS AML patients. Our results demonstrating i) significantly increased CBS transcript levels in DS myeloblasts and a correlation with in vitro ara-C sensitivity and ara-CTP generation, ii) dramatic increased in ara-C metabolism to ara-CTP in vitro in leukemia cell lines transfected with the CBS cDNA, associated with increased in vitro and in vivo ara-C sensitivity, and iii) significant differences in frequency of the 844ins68 CBS gene polymorphism in DS myeloblasts, provide compelling evidence of an integral relationship between CBS gene expression and ara-C metabolism. This mechanisms is likely a major factor that accounts for the increased chemotherapy sensitivity and high cure rates of pediatric DS AML patients. This study will continue to examine over novel hypothesis and laboratory observations which bridge basic research (e.g., understanding the transcriptional regulation of CBS, determining the relation of CBS mutations/polymorphisms and ara-C metabolism) and apply this work to translational studies using clinical leukemia samples. These findings may ultimately be applied clinically to improve the treatment and cure of AML. The specific aims of the study are: 1) To characterize the transcriptional regulation of the CBS gene in leukemia cell lines and clinical leukemia samples; 2) To develop CBS-transfected AML cell models and to determine the mechanistic basis for the effects of CBS on ara-C metabolism and sensitivity; 3) To determine the relationships between CBS gene expression and ara-C sensitivities in patient myeloblasts with wild-type CBS and with the T833C, G919A, 844ins68 CBS gene variants.

该项目的目的是更好地了解唐氏综合症（DS）儿童急性髓细胞性白血病（AML）的生物学，与染色体21位基因的相关性，胱胱氨而在硫代氨基蛋白β-合酶（CBS）和对胞质阿拉伯糖苷（ARA-C）基于基于的甲状腺素（ARA-C）的治疗有关的生物学。童年AML的预后最差，所有主要儿童期癌症的相对存活率约为37％。相比之下，与非DS基于ARA-C的方案相比，与非DS儿童相比，AML患有AML的DS儿童代表了独特的白血病患者（70-100％，复发率<15％）的率明显更高（70-100％，复发率<15％）。因此，确定DS AML患者极高的治愈率的生物学基础可能具有非常重要的含义，并且可能会导致所有患者的AML治疗改善。我们先前的结果已经开始阐明导致DS AML患者EFS增加的基本机制。我们的结果表明i）i）DS髓细胞中CBS的转录水平显着提高，以及与体外ARA-C敏感性和ARA-CTP产生的相关性，ii）ii）ARA-C代谢中的ARA-CCTP急剧增加，在白血病中与CBS CDNA的频率不同，与IN IN IN IN IN IN IN VIV ana ARAA ARAA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA ARA A. 844INS68 CBS基因多态性在DS骨髓细胞中，提供了令人信服的证据，证明了CBS基因表达与ARA-C代谢之间存在不可或缺的关系。这种机制可能是说明化学疗法敏感性提高和小儿DS AML患者的高度治愈率的主要因素。这项研究将继续研究对新的假设和实验室观察结果，这些假设和实验室观察桥接基础研究（例如，了解CBS的转录调节，确定CBS突变/多态性和ARA-C代谢的关系），并将这项工作应用于使用临床白血病样品的翻译研究。这些发现最终可以在临床上应用于改善AML的治疗和治疗。该研究的具体目的是：1）表征白血病细胞系和临床白血病样品中CBS基因的转录调节； 2）开发CBS转染的AML细胞模型，并确定CBS对ARA-C代谢和敏感性影响的机械基础； 3）确定具有野生型CBS的患者骨髓细胞中CBS基因表达与ARA-C敏感性之间的关系，以及T833C，G919A，844INS68 CBS基因变体。