Imaging and therapy of tumors using biotinylated cell surface docking sites

描述(申请人提供)：报告基因的非侵入性、实时成像已成为生物医学应用中的重要工具，包括肿瘤检测、细胞跟踪和基因治疗。在这里，通过表达一种可以用多种方式成像的单一报告蛋白(22 KDa)来评估一种通用、有效的技术，用于在培养和体内对肿瘤细胞进行靶向、成像和治疗。首先，细胞表面受体将被设计成有效地介导代谢生物素化。其次，靶向分子将包括使用标记的链霉亲和素部分进行磁共振、光学和正电子发射断层扫描的成像剂。第三，将探索白喉毒素的催化结构域与链霉亲和素结合，选择性杀伤表达生物素表面受体的肿瘤细胞。最后，肿瘤的生长和治疗将通过使用稳定表达一种新的荧光素酶的肿瘤细胞的生物发光来监测，这种酶比目前使用的荧光素酶敏感得多。重要的是，这些融合结构可以很容易地翻译到人类身上，因为它们与AAV载体兼容，生物素-链霉亲和素系统以及磁性纳米颗粒和放射性核素正在临床试验中使用。 在这个项目中，将探索一种新的靶向、成像和治疗肿瘤的方法。首先，病毒将经过基因改造，携带特定的DNA序列(转基因)，一旦它感染培养中和活着的小鼠的肿瘤细胞，它将触发这些细胞产生一种特定的蛋白质，使其成为白喉毒素、杀伤剂以及磁共振(MR)和正电子发射断层扫描(PET)的成像试剂，因此只会对肿瘤进行成像和杀死。

DESCRIPTION (provided by applicant): Non-invasive, real time imaging of reporter genes has become an important tool in biomedical applications, including detection of tumors, cell tracking and gene therapy. Here, a versatile, potent technique for targeting, imaging and therapy of tumor cells in culture and in vivo will be evaluated by expressing a single reporter protein (22 kDa) which can be imaged with multiple modalities. First, cell surface receptors will be engineered to efficiently mediate metabolic biotinylation. Second, targeting molecules will include imaging agents for magnetic resonance, optical and positron emission tomography using labeled streptavidin moieties. Third, catalytic domain of diphtheria toxin incorporating streptavidin will be explored to selectively kill tumor cells expressing biotinylated surface receptors. Finally, tumor growth and therapy will be monitored by bioluminescence using tumor cells stably expressing a novel luciferase that is far more sensitive than the ones currently in use. Importantly, these fusion constructs can be easily translated into humans since they are compatible with AAV vectors and the biotin-streptavidin system as well as magnetic nanoparticles and radionuclides are being used in clinical trials. In this project, a new method to target, image, and treat tumors will be explored. First, a virus will be genetically modified to carry a specific DNA sequence (transgene) that once it infects tumor cells in culture and in living mice, it will trigger these cells to produce a specific protein that would make them a selective, easy target for diphtheria toxin, a killing agent, as well as imaging agent for magnetic resonance (MR) and positron emission tomography (PET) therefore only tumors will be imaged and killed.