The Tetrazine Ligation for Efficient 18F Labeling and Pretargeted Imaging/Radioth

摘要 提出了一种简单、快速和通用的战略，将放射性核素纳入 用于癌症成像和预靶向免疫治疗的生物分子。该战略基于 生物共轭反应在福克斯实验室开发：四嗪和反式之间的反应， 环辛烯（TCO）。“四嗪-TCO连接”的快速动力学（k2 e 250，000 L <$mol/s-1）使得能够快速 在低微摩尔浓度下，在几分钟内，并且没有过量的反应物的反应性。这么快 反应性为蛋白质和抗体的修饰以及用于执行 体内反应。该提案涉及来自分子成像中心（MIC）的合作努力， 南加州大学（USC）和福克斯集团（UD）。本申请的目的是使用 四嗪连接法构建高特异性的18F标记蛋白 用于癌症成像。此外，我们还将开发一种新的预靶向成像， 允许通用和直接标记单克隆抗体的放射免疫治疗方法 （mAb）与成像/治疗性同位素一起使用，而不对正常器官进行严重的辐射暴露。 为了实现这些目标，我们将首先开发具有快速动力学和稳定性的生物缀合反应。 基于四嗪-TCO连接的体内稳定性。由于四嗪-TCO连接的快速动力学使得能够进行快速的 反应性在低微摩尔浓度在几分钟内，没有过量的反应物，我们将 将该反应转化为可用于构建18F标记蛋白的有效方法， 高比活性。最后，我们还将建立一种化学预靶向方法， 基于四嗪-TCO连接和抗EphB 4抗体的癌症成像/放射免疫治疗。 总之，在本申请中，我们正在开发用18F标记蛋白质的有效方法， 化学预靶向方法，可用于乳腺的预靶向成像和放射免疫治疗 癌将用EphB 4抗体、F（ab '）2和Fab测试这些方法的可行性。成功 这些新的成像和治疗方法可以使乳腺癌的诊断，使直接 监测对治疗干预的反应，并可能显著改善乳腺癌治疗 功效此外，这些新开发的方法可以在许多其他领域中具有重要的应用。 癌症类型，因此对大量癌症患者具有显著的临床影响

Abstract Proposed is the development of a simple, fast and universal strategy for incorporating radionuclides into biomolecules for applications for cancer imaging and pretargeted immunotherapy. The strategy is based on a bioconjugation reaction developed in the Fox laboratories: the reaction between tetrazines and trans- cyclooctenes (TCO). The fast kinetics of the 'tetrazine-TCO ligation' (k2 e 250,000 L¿mol/s-1) enable fast reactivity at low micromolar concentrations within minutes and without an excess of either reactant. This fast reactivity provides unprecedented opportunities for protein and antibody modification and for performing reactions in vivo. This proposal involves collaborative effort from the Molecular Imaging Center (MIC) at University of Southern California (USC) and the Fox group (UD). An objective of this application is to use the tetrazine ligation to develop efficient methods for the construction of 18F labeled proteins with high specific activity for cancer imaging. Moreover, we will also develop a novel pretargeted imaging and radioimmunotherapy method that will allow for universal and straightforward tagging of monoclonal antibodies (mAbs) with an imaging/therapeutic isotope without severe radiation exposure towards normal organs. To achieve these objectives, we will first develop bioconjugation reactions with fast kinetics and robust in vivo stability based on the tetrazine-TCO ligation. As the fast kinetics of tetrazine-TCO ligation enable fast reactivity at low micromolar concentrations within minutes and without an excess of either reactant, we will transform this reaction into efficient methods that could be used for the construction of 18F labeled proteins with high specific activity. At last, we will also establish a chemical pretargeting approach that for pretargeted imaging/radioimmunotherapy of cancer based on the tetrazine-TCO ligation and anti-EphB4 antibody. In summary, in this application, we are developing efficient methods for proteins labeling with 18F, and a chemical pretargeting approach that could be used for pretargeted imaging and radioimmunotherapy of breast cancer. The feasibility of these approaches will be tested with EphB4 antibody, F(ab')2, and Fab. The success of these novel imaging and therapy approached could enable breast cancer diagnosis, make possible direct monitoring of responses to therapeutic interventions, and may significantly improve breast cancer treatment efficacy. Moreover, these newly developed approaches could have important applications in many other cancer types, and thus have a significant clinical impact on a very large number of cancer patients