Cetuximab是首个上市的靶向EGFR的单克隆抗体药物，为监测其疗效，主要应用LC-MS/MS定量分析和正电子发射断层扫描成像方法研究cetuximab在生物体中的药代和静态分布。尽管cetuximab在安全性和毒副作用上优于传统化疗药物，但在临床癌症治疗中它仅对部分病人有效。研究表明，cetuximab与靶标的结合情况以及内吞作用可能对药效有重要影响，而现有方法通常只能测定cetuximab本身的浓度及静态组织分布，无法进行两者之间相互作用及内吞过程的动态分析。对此，本项目拟在cetuximab特定位点标记“OFF”状态的荧光分子，通过药物与靶标的结合使荧光分子被“Turn ON”，并结合活细胞荧光成像技术，建立可视化检测cetuximab与EGFR相互作用的新方法，从分子层面揭示可能影响两者结合过程的因素，如浓度、受体状态、内吞作用等，为提高其临床有效性提供参考。

Cetuximab is the first FDA-approved anti-EGFR monoclonal antibody drug. In order to evaluate its therapeutic performance, both LC-MS/MS and positron emission tomography have been used to study its pharmacokinetics and distribution. Cetuximab is demonstrated to be safer with less toxic and side effects compared to traditional chemotherapies, but it is also faced with challenges including a lack of therapeutic response in the treatment of cancer. Mechanism studies indicated both the drug-target interaction and the subsequent internalization are crucial determinants of the therapeutic effect. However, available detection methods can either measure the concentration or distribution of cetuximab, without analysis of the dynamic interaction between the drug and its target. To this end, we plan to develop a new method to visualize the cetuximab-target interaction, through a combination of site-selective labeling of the antibody with a turn-on strategy indicative of the drug-target binding. With this method, we will explore factors that may affect their interaction in hope of coming up with solutions to achieve better clinical performance.