SELECTIVE THERAPY OF NEUROBLASTOMA

神经母细胞瘤的选择性治疗

• 批准号: 6545435
• 负责人: PHILIP M POTTER
• 金额: $ 2.25万
• 依托单位: ST. JUDE CHILDREN'S RESEARCH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-09 至 2003-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6545435
• 关键词: CD34 molecule; DNA topoisomerases; bone marrow; carboxylic ester hydrolases; complementary DNA; cytotoxicity; drug metabolism; endoplasmic reticulum; enzyme activity; enzyme inhibitors; gene expression; genetic promoter element; genetic transcription; hematopoietic stem cells; human tissue; laboratory mouse; neoplasm /cancer chemotherapy; neoplastic cell; neuroblastoma; prodrugs; protein structure function; transcription factor

Patients with advanced stage, N-myc amplified neuroblastoma have only a 2-30 percent 3-year progression-free survival. Therapy with surgery, chemotherapy, and purged autologous transplant is often not curative since tumor frequently recurs at the original site of disease or as a consequence of an incompletely purged bone marrow. This proposal describes an approach designed to produce tumor cell-specific cytotoxicity of neuroblastomas overexpressing N-MYC, based on exploiting the function of N-MYC as a transcription factor. The hypothesis to be tested is that the selective induction of transcription by N-MYC of a carboxylesterase gene will produce selective cytotoxicity when tumor cells are exposed to the topoisomerase I inhibitor CPT-11. The rationale for this hypothesis is based upon the observation that carboxylesterases convert the prodrug CPT-11 to its active metabolite SN-38. Specifically, we propose to test whether endogenous overexpression of N-MYC in tumor cells can selectively transactivate the N-MYC-responsive ornithine decarboxylase promoter allowing transcription of a carboxylesterase. When tumor cells overexpressing N-MYC, and therefore the carboxylesterase, are exposed to CPT-11, the drug will be converted to SN-38 and produce tumor-selective cell kill. We will examine the feasibility of this approach as a potential treatment for minimum residual disease and in the purging of marrow for autologous transplant. The goals of this proposal are to determine: 1) the most appropriate form of rabbit liver carboxylesterase for CPT-11 activation; 2) A) that specific expression of carboxylesterase can be achieved in neuroblastoma cells overexpressing N-MYC from N-MYC responsive promoters, and B) that selective expression of carboxylesterase by tumor cells overexpressing N-MYC can convert CPT-11 to SN-38 and produce tumor cell-specific cytotoxicity; 3) whether this approach eradicates residual disease in a xenograft model; 4) A) whether the proposed approach can be used to purge neuroblastoma cells from marrow using a mouse xenograft model, and B) to purge primary neuroblastoma cells from human peripheral stem (CD34+) cells, with minimal toxicity to hematopoietic cells.

晚期N-myc扩增的神经母细胞瘤患者的3年无进展生存率仅为2- 30%。 用手术、化疗和净化的自体移植进行的治疗通常是不能治愈的，因为肿瘤经常在疾病的原始部位复发或作为骨髓不完全净化的结果。该提案描述了一种设计用于产生过表达N-MYC的神经母细胞瘤的肿瘤细胞特异性细胞毒性的方法，该方法基于利用N-MYC作为转录因子的功能。 待检验的假设是，当肿瘤细胞暴露于拓扑异构酶I抑制剂CPT-11时，羧酸酯酶基因的N-MYC对转录的选择性诱导将产生选择性细胞毒性。该假设的基本原理是基于羧酸酯酶将前药CPT-11转化为其活性代谢物SN-38的观察结果。 具体来说，我们建议测试是否内源性N-MYC在肿瘤细胞中的过度表达可以选择性地反式激活N-MYC响应的鸟氨酸脱羧酶启动子，允许羧酸酯酶的转录。 当过表达N-MYC的肿瘤细胞，因此羧酸酯酶，暴露于CPT-11时，药物将转化为SN-38并产生肿瘤选择性细胞杀伤。 我们将研究这种方法作为最小残留疾病的潜在治疗方法和自体移植骨髓净化的可行性。本研究的目的是确定：1）最适合激活CPT-11的兔肝羧酸酯酶形式; 2）A）羧酸酯酶的特异性表达可以在从N-MYC应答启动子过表达N-MYC的神经母细胞瘤细胞中实现，和B）通过过表达N-MYC的肿瘤细胞选择性表达羧酸酯酶可以将CPT-11转化为SN-38并产生肿瘤细胞-特异性细胞毒性; 3）该方法是否根除异种移植物模型中的残留疾病; 4）A）所提出的方法是否可用于使用小鼠异种移植物模型从骨髓中清除成神经细胞瘤细胞，以及B）从人外周干（CD 34+）细胞中清除原代成神经细胞瘤细胞，对造血细胞的毒性最小。