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: 6634090
• 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/6634090
• 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.

该项目的目标是更好地了解唐氏综合症 (DS) 儿童急性髓性白血病 (AML) 的生物学特性，该生物学与 21 号染色体定位基因、胱硫醚-β-合酶 (CBS) 和对胞嘧啶阿拉伯糖苷的反应相关（ara-C）为基础的治疗。在所有主要儿童癌症中，儿童 AML 的预后最差，五年相对生存率约为 37%。相比之下，患有 AML 的 DS 儿童代表了一组独特的白血病患者，因为与接受 ara 治疗的非 DS 儿童相比，其无事件生存 (EFS) 率显着较高（70-100%，复发率 < 15%）。 -基于C的协议。因此，确定 DS AML 患者极高治愈率的生物学基础可能具有非常重要的意义，并有可能改善所有患者的 AML 治疗。我们之前的结果已经开始揭示 DS AML 患者 EFS 显着增加的潜在机制。我们的结果表明 i) DS 成髓细胞中的 CBS 转录水平显着增加，并且与体外 ara-C 敏感性和 ara-CTP 生成相关，ii) 在体外转染 ara-C 的白血病细胞系中，ara-C 代谢显着增加到 ara-CTP与体外和体内 ara-C 敏感性增加相关的 CBS cDNA，以及 iii) DS 成髓细胞中 844ins68 CBS 基因多态性频率的显着差异，提供了CBS 基因表达与 ara-C 代谢之间存在不可分割的关系，这是令人信服的证据。这种机制可能是儿童 DS AML 患者化疗敏感性增加和治愈率高的主要因素。这项研究将继续检验连接基础研究的新假设和实验室观察（例如，了解 CBS 的转录调控、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临床白血病的转化研究样品。这些发现最终可能应用于临床以改善 AML 的治疗和治愈。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本中CBS基因的转录调控； 2) 建立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制基础； 3) 确定具有野生型 CBS 和 T833C、G919A、844ins68 CBS 基因变体的患者成髓细胞中 CBS 基因表达和 ara-C 敏感性之间的关系。