Heat Activated Gene Therapy Using Radiomimetic CdtB

使用拟放射 CdtB 的热激活基因治疗

• 批准号: 6876886
• 负责人: Michael Jude Borrelli
• 金额: $ 27.21万
• 依托单位: WILLIAM BEAUMONT HOSPITAL RESEARCH INST
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-28 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6876886
• 关键词: Adenoviridae; antimetabolites; bacterial toxins; biological signal transduction; biotechnology; blood chemistry; brain neoplasms; cell death; cytotoxicity; gene delivery system; gene expression; gene therapy; genetic transcription; heat shock proteins; heat stimulus; laboratory rabbit; magnetic resonance imaging; neoplasm /cancer thermotherapy; nonhuman therapy evaluation; pancreas neoplasms; polymerase chain reaction; radiation; transfection /expression vector

DESCRIPTION (provided by applicant): The central hypothesis is that effective cancer gene therapy can be achieved using a highly toxic transgene that is expressed controllably from a heat-inducible promoter. To test this, cytolethal distending toxin B (CdtB), the cytotoxic component of a tripartite bacterial proteotoxin, was placed into an adenovirus vector under control of a modified human HSP70B heat shock promoter that is extremely silent until heal shocked at 41.0 degrees C or higher. Aim 1 is to optimize using this heat-activatable CdtB gene therapy to establish local tumor control in a rabbit VX2 brain tumor model and to protract animal survival. Aim two is to deliver the adenovirus vectors with tissue permeabilizing agents that increase the interstitial space to promote vector diffusion throughout solid tumors to ascertain if this increases treatment efficacy. It is postulated that using the permeabilizers will increase the fraction of tumor cells that get infected to express CdtB to control tumors more efficiently and permit larger tumors to be treated successfully. Aim three is to explicate the mechanisms of CdtB bystander killing. Treatment efficacy is dependent upon bystander killing of cells adjacent to those infected with and expressing the CdtB transgene. Although CdtB bystander killing has been observed in vitro and in vivo, little is known about it. Experiments will determine if bystander killing is mediated by a freely diffusible extracellular signal or if cell-cell contact and gap junction communication are requisite. Assays will also establish if the bystander cells die by apoptosis or other death mechanisms and will identify the signals that initiate bystander killing. Some tumors, e.g., glioblastoma multiforme, pancreatic tumors, etc. are more refractory to conventional radiotherapy, and chemotherapy, making local tumor control difficult to achieve. Additionally, many tumors recur locally with high frequency and surgery is often impossible and/or radiotherapy options are limited because surrounding normal tissues have accrued their tolerance radiation dose. Consequently, complementary therapies that can improve local control for primary and recurrent cancers are needed. The proposed study will test the potential of heat-activated CdtB gene therapy to help satisfy this need.

描述(由申请人提供)：中心假设是，有效的癌症基因治疗可以使用从热诱导启动子可控制表达的剧毒转基因来实现。为了测试这一点，将三方细菌蛋白毒素的细胞毒性成分细胞致死性膨胀毒素B(CDtB)置于腺病毒载体中，在修改的人类HSP70B热休克启动子的控制下，该启动子极其沉默，直到在41.0摄氏度或更高的温度下愈合休克。目的1是优化利用这种可热激活的CDtB基因疗法在兔VX2脑瘤模型中建立局部肿瘤控制，并延长动物生存时间。 第二个目的是将腺病毒载体与组织渗透剂一起运送，以增加组织间隙，促进载体在实体瘤中的扩散，以确定这是否提高了治疗效果。据推测，使用渗透剂将增加被感染的肿瘤细胞表达CDtB的比例，从而更有效地控制肿瘤，并使较大的肿瘤得以成功治疗。 目的三是阐明CdtB对旁观者的杀伤机制。治疗效果取决于旁观者对感染并表达CDtB转基因的细胞邻近的细胞的杀伤。尽管在体外和体内观察到了对CdtB旁观者的杀伤作用，但对其知之甚少。实验将确定旁观者的杀戮是由自由扩散的细胞外信号介导的，还是细胞间接触和缝隙连接通讯是必要的。化验还将确定旁观者细胞是否死于凋亡或其他死亡机制，并将识别引发旁观者死亡的信号。 一些肿瘤，如多形性胶质母细胞瘤、胰腺肿瘤等，对常规放疗和化疗更具耐受性，使得局部肿瘤控制困难。此外，许多肿瘤局部复发的频率很高，手术往往是不可能的和/或放射治疗的选择是有限的，因为周围正常组织已经积累了耐受的辐射剂量。因此，需要补充疗法来改善对原发和复发癌症的局部控制。这项拟议的研究将测试热激活CdtB基因疗法的潜力，以帮助满足这一需求。