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）： 肿瘤缺氧常见于许多人类癌症中。它们的存在与放射和化学耐药性（一种更具侵袭性的表型）有关，并且是治疗结果的重要预后因素。该提案的长期目标是开发一种图像引导的治疗策略，结合缺氧成像、放射治疗和基因治疗，克服缺氧介导的放射抗性并改善癌症治愈。该策略的主要方面是 1) 肿瘤缺氧的成像和定位，2) 图像引导递送表达放射增敏效应基因以及缺氧诱导的标记基因的载体，3) 验证载体递送至缺氧细胞通过分子成像，4）通过辐射根除肿瘤。为了评估和验证这种方法，有三个具体目标：在具体目标 I 中，我们将设计和构建载体，表达来自缺氧诱导启动子的标记基因 HSV1-tk 和拮抗 DNA 断裂修复的效应基因。 ，并用它们稳定转染肿瘤细胞系。将在体外和体内评估组成型或诱导型表达各种效应基因的肿瘤细胞的放射增敏程度；病毒tk基因在缺氧细胞中的特异性表达将通过TK介导的124I-FIAU在裸鼠移植肿瘤中的捕获的microPET成像来评估。 在Specific Aim II中，将构建含有缺氧标记基因和效应基因的复制缺陷型腺病毒。然后将在体外和体内研究腺病毒介导的标记基因和效应基因的递送功效、标记tk基因的缺氧诱导性以及效应基因的放射增敏作用。 在具体目标 III 中，我们将把啮齿动物和人类肿瘤移植到裸鼠体内，使用 microPET/18F-FMISO 成像识别和定位缺氧子体积。在这些图像的引导下，腺病毒载体将被递送至肿瘤的缺氧区域，并且基于 TK 介导的 124I-FIAU 捕获的 microPET 成像将用于验证载体优先递送至缺氧细胞。然后将评估肿瘤对辐射的反应。 在初步研究中，我们已经证明反义 Ku70 或显性失活 Ku70 片段在体外和体内显着使缺氧肿瘤细胞放射增敏，并且它们可以通过腺病毒载体成功递送到肿瘤中。对于肿瘤缺氧靶向，我们利用 18F-FMISO 实现了 microPET 成像，并开发了用于引导腺病毒载体注射的立体定位模板。此外，我们还表明，可以在体内使用 124I-FIAU / microPET 轻松检测标记 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的指南，以改善癌症治疗的结果。