In Vivo Image Guidance for Gene-Radiation Therapy

基因放射治疗的体内图像指导

• 批准号: 6925200
• 负责人: GLORIA C LI
• 金额: $ 49.7万
• 依托单位: SLOAN-KETTERING INST CAN RESEARCH
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6925200
• 关键词: Adenoviridae; DNA repair; athymic mouse; bioimaging /biomedical imaging; biotechnology; cell line; gene therapy; genetic markers; genetic strain; hypoxia; image guided surgery /therapy; laboratory rat; molecular /cellular imaging; neoplasm /cancer blood supply; neoplasm /cancer radiation therapy; neoplasm /cancer transplantation; positron emission tomography; radiation resistance; radiation sensitivity; radiotracer; transfection /expression vector

DESCRIPTION (provided by applicant): Tumor hypoxia is often found in many human cancers; their presence has been implicated in radio- and chemo-resistance, a more aggressive phenotype, and is an important prognostic factor of treatment outcome. The long term goal of this proposal is to develop an image-guided therapeutic strategy, combining hypoxia imaging, radiotherapy and gene therapy, to overcome hypoxia-mediated radioresistance and improve cancer cure. The major facets of this strategy are 1) the imaging and localization of tumor hypoxia, 2) image-guided delivery of vectors that express a radiosensitizing effector gene as well as a hypoxia-induced marker gene, 3) verification of vector delivery to hypoxic cells by molecular imaging, and 4) tumor eradication by radiation. To evaluate and validate this approach, there are three Specific Aims: In Specific Aim I, we shall design and construct vectors that express both a marker gene HSV1-tk from a hypoxia-inducible promoter and an effector gene that antagonizes the repair of DNA breaks, and use them to stably transfect tumor cell lines. The degree of radiosensitization of tumor cells that constitutively or inducibly express various effector genes will be assessed in vitro and in vivo; the specific expression of the viral tk gene in hypoxic cells will be evaluated by microPET imaging of TK-mediated trapping of 124I-FIAU in tumors transplanted in nude mice. In Specific Aim II, replication defective adenovirus containing the hypoxia marker gene and the effector gene will be constructed. The efficacy of adenovirus-mediated delivery of the marker gene and the effector gene, the hypoxia inducibility of the marker tk gene, and the radiosensitizing effect of the effector gene will then be studied in vitro and in vivo. In Specific Aim III, we shall transplant rodent and human tumors into nude rats, identify and localize the hypoxic sub-volume using microPET/18F-FMISO imaging. Guided by these images, adenoviral vectors will be delivered to the hypoxic region of the tumor and microPET imaging based on TK-mediated trapping of 124I-FIAU will be used to verify the preferential delivery of the vectors to hypoxic cells. The tumor's response to radiation will then be evaluated. In pilot studies, we have shown that antisense Ku70 or a dominant negative Ku70 fragment significantly radiosensitizes hypoxic tumor cells in vitro and in vivo, and that they can be successfully delivered into tumors by adenoviral vectors. For tumor hypoxia targeting, we have implemented microPET imaging with 18F-FMISO and developed a stereotaxic template for guiding adenoviral vector injection. Also, we have shown that the hypoxia-induction of the marker tk gene can be readily detected using 124I-FIAU / microPET in vivo. The information gained from the proposed preclinical studies will serve as a guide in the design of clinical strategy to improve the outcome of cancer therapy.

描述（由申请人提供）： 肿瘤缺氧通常在许多人类癌症中发现。它们的存在与放射性和化学抗性，更具侵略性的表型有关，并且是治疗结果的重要预后因素。该建议的长期目标是制定图像引导的治疗策略，结合缺氧成像，放射疗法和基因治疗，以克服缺氧介导的放射线并改善癌症治疗。该策略的主要方面是1）肿瘤缺氧的成像和定位，2）图像引导的载体的递送表达辐射敏感性效应基因以及缺氧诱导的标记基因，3）通过辐射通过分子成像验证向载体递送到缺氧细胞的载体递送到低氧细胞。为了评估和验证这种方法，有三个特定的目的：在特定目的I中，我们将设计和构造向量，这些向量既表达了从缺氧诱导的启动子和效应基因，又表达了标记基因HSV1-TK，又是拮抗DNA破裂的修复，并利用它们稳定地转移肿瘤细胞系。在体外和体内，将评估组成或诱导表达各种效应基因的肿瘤细胞的放射敏化程度；病毒TK基因在低氧细胞中的特异性表达将通过MicroPET成像的TK介导的124i-FIAU的捕获在裸鼠移植的肿瘤中的捕获。 在特定的目标II中，将构建包含缺氧标记基因和效应基因的复制缺陷腺病毒。腺病毒介导的标记基因递送和效应基因的疗效，标记物TK基因的缺氧诱导性以及效应基因的放射敏化作用将在体外和体内进行研究。 在特定的目标III中，我们应将啮齿动物和人类肿瘤移植到裸鼠中，使用Micropet/18F-Fmiso成像识别和定位低氧亚卷。在这些图像的指导下，将使用基于TK介导的124i-FIAU捕获的腺病毒载体将其传递到肿瘤的低氧区域，并将其用于MicroPET成像，以验证载体对低氧细胞的优先递送。然后将评估肿瘤对辐射的反应。 在初步研究中，我们表明反义KU70或显性负的KU70片段在体外和体内显着放射敏感的低氧肿瘤细胞，并且可以通过腺病毒载体成功地将其递送到肿瘤中。对于肿瘤缺氧的靶向，我们已经用18F-FMISO实施了MicroPET成像，并开发了一种立体定位模板，用于指导腺病毒载体注射。同样，我们已经表明，使用124i-fiau / micropet在体内很容易检测出标记物TK基因的缺氧诱导。从拟议的临床前研究中获得的信息将作为设计临床策略设计以改善癌症治疗结果的指南。