利用量子点探针单分子荧光跟踪技术研究整合素内吞循环在肿瘤细胞迁移中的作用机制

整合素是构成细胞粘着斑的关键蛋白，通过内吞循环调控粘着斑的组装和解离，在肿瘤细胞迁移中发挥重要作用。由于其内吞循环过程的复杂性和以往生物研究方法的局限性，目前为止整合素内吞循环在肿瘤细胞迁移中的具体作用机理仍未阐明。单分子荧光跟踪方法是近年来被证实为研究蛋白分子运动的有效方法，为将此方法应用于整合素研究，我们拟在量子点标记、多荧光成像和轨迹数据分析三方面加以完善，建立单分子荧光跟踪整合素实验平台。我们将在研究表皮生长因子受体（EGFR）内吞运输的基础上，单分子荧光跟踪整合素α5β1在肿瘤细胞迁移中的完整内吞循环过程，研究其内吞循环的模式、路径和动力学，以揭示其促进肿瘤细胞迁移的作用机理，并且通过比较不同迁移速度的肿瘤细胞进一步研究整合素α5β1内吞循环影响肿瘤细胞迁移的机制。本项目在揭示整合素内吞循环在肿瘤细胞迁移中的作用机制，及在探索癌症转移机理和帮助抗癌药物研发等方面有重要意义。

Integrins, the key component proteins of focal adhesions, can regulate the assembly and disassembly of focal adhesions through the endocytosis and recycling (EAR), which plays an important role in tumor cell migration. The mechanism underling actions of tumor cell migration through integrin EAR is unclear, due to the complexity of integrin EAR and the limitation of previous biological approaches. The single-molecule fluorescence tracking method emerged recently prove to be effective in studying the movement of protein molecules. To apply this method to integrin, we will establish single-molecule fluorescence tracking platform for integrin research，by improving the techniques in three areas: quantum dot labeling, multicolor high-speed synchronous imaging and trajectory identification and segmentation method. In this project, based on our previous study of the endocytic trafficking of EGFR, we will track α5β1 integrin during the whole EAR process by single-molecule fluorescence imaging, and study the mode, pathway and dynamics of the integrin EAR, in order to reveal the mechanism of integrin EAR promoting tumor cell migration. Furthermore, we will explore the mechanism of integrin EAR affecting tumor cell migration by comparing tumor cells in different migration speed. This project is of great importance not only to elucidate mechanism of action on tumor cell migration by integrin EAR, but also to understand the process of tumor metastasis and to provide clues for chemotherapeutic drug design.