CX3CL1与CX3CR1特异性识别并且促进肿瘤转移的分子机制的研究

Chemokines are small cytokines known for their ability to induce migration of cells. Chemokines mediate their functions through binding to G-protein-coupled receptors (GPCRs) on the target cells. chemokines can be divided into four subfamilies, CXC, CC, C and CX3C. CX3CL1 is the only member of the CX3C subfamily. CX3CL1-driven chemotaxis and adhesion are mediated by CX3CR1 expressed on the target cells. CX3CL1 and its receptor CX3CR1 play a complex role in tumorigenesis and tumor progression of multiple cancers and especially they are of great importance in tumor metastasis. The important role of CX3CL1/CX3CR1 makes them an attractive candidate for the development of therapeutic strategies. In this project we try to present the structures of CX3CR1 and the complex of CX3CR1 with CX3CL1 via structural biology methods. With the structure analysis and comparison and the chemotaxis assay of tumor cells, the similarities and differences between CX3CR and other chemokine receptors will be revealed and the mechanism of the specific recognition of CX3CR1 with CX3CL1 and the tumor metastasis promoted by them will be clarified. And additionally, these results will expound the rationale of the inhibitor chemicals and shed light on the development of CX3CR1 inhibitor to suppress tumor metastasis.

趋化因子是一类可以诱导细胞移动的细胞因子，它们发挥作用的方式是结合靶细胞上的G蛋白偶联受体（GPCR）。趋化因子分为CXC、CC、C、CX3C四类，CX3CL1是唯一一个CX3C类趋化因子。CX3CL1介导的趋化及黏附作用是通过结合靶细胞上的CX3CR1受体实现的。在多种肿瘤的发生和发展过程中，CX3CL1及其受体CX3CR1起到了复杂的作用，尤其是在肿瘤转移过程中发挥了重要作用。所以CX3CL1和CX3CR1已经成为新的肿瘤治疗的靶点。本课题通过结构生物学的方法解析CX3CR1以及CX3CL1-CX3CR1复合物的结构，通过结构分析与比较以及肿瘤细胞趋化实验，揭示CX3CR与其他趋化因子受体的异同点，阐明CX3CL1与CX3CR1特异性识别并且促进肿瘤转移的机制，阐明抑制剂类化学药物的作用机理，为具有抑制肿瘤转移作用的CX3CR1抑制剂的开发奠定基础。

趋化因子是一类可以诱导细胞移动的细胞因子。趋化因子分为CXC、CC、C、CX3C四类，CX3CL1是唯一一个CX3C类趋化因子。CX3CL1介导的趋化及黏附作用是通过结合靶细胞上的受体CX3CR1实现的。在多种肿瘤的发生和发展过程中，CX3CL1及其受体CX3CR1起到了复杂的作用，尤其是在肿瘤转移过程中发挥了重要作用。本项目针对CX3CL1及其受体CX3CR1进行结构与功能研究。结构生物学研究方面，经过分子克隆、蛋白质表达与纯化、冷冻电镜、X射线晶体学、计算模拟等过程，获得了CX3CL1-CX3CR1复合物的结构。通过结构分析揭示了CX3CL1-CX3CR1的结构特点，阐明了CX3CL1与CX3CR1的特异性识别方式和重要的相互作用位点。通过与CX3CL1-US28复合物的结构比较，阐明了CX3CR1与同源蛋白US28识别CX3CL1的异同点。通过与其他趋化因子受体及其抑制剂的结构比较，阐明了小分子抑制剂的作用原理，为以CX3CR1为靶点的小分子药物的设计提供了直观和确切的近原子水平的信息。肿瘤转移功能学研究方面，通过基因过表达和敲低、关键分子的表达水平检测、转录组测序、细胞迁移侵袭能力检测、外泌体提取和分析、临床样本免疫组化等过程，从分子水平、细胞水平和组织水平，阐明了CX3CR1在肿瘤转移中的促进作用和机制，并为临床预测肿瘤转移情况提供了新的分子标记物。