Imaging and therapy of tumors using biotinylated cell surface docking sites

描述（由申请人提供）：报告基因的非侵入性、真实的时间成像已经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，一个通用的，有效的技术，在培养和体内的肿瘤细胞的靶向，成像和治疗将通过表达一个单一的报告蛋白（22 kDa），可以用多种方式成像进行评估。首先，细胞表面受体将被工程化以有效地介导代谢生物素化。第二，靶向分子将包括使用标记的链霉亲和素部分的用于磁共振、光学和正电子发射断层扫描的成像剂。第三，白喉毒素催化结构域结合链霉亲和素将探索选择性地杀死表达生物素化表面受体的肿瘤细胞。最后，肿瘤生长和治疗将通过使用稳定表达新型荧光素酶的肿瘤细胞的生物发光来监测，该荧光素酶比目前使用的荧光素酶灵敏得多。重要的是，这些融合构建体可以容易地翻译到人类中，因为它们与AAV载体和生物素-链霉亲和素系统以及磁性纳米颗粒和放射性核素相容，正在临床试验中使用。 在该项目中，将探索一种新的靶向、成像和治疗肿瘤的方法。首先，病毒将被基因改造以携带特定的DNA序列（转基因）一旦它感染了培养物和活小鼠中的肿瘤细胞，它将触发这些细胞产生一种特定的蛋白质，使它们成为白喉毒素的选择性，容易的靶点，白喉毒素是一种杀伤剂，以及用于磁共振（MR）和正电子发射断层扫描（PET）的成像剂，因此只有肿瘤将被成像和杀死。

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.