非典型性受体酪氨酸激酶ROR2在正常成人组织中基本不表达，但在胰腺导管癌等癌症组织中高表达，是潜在的药物靶标。Wnt5a-ROR2信号轴对ROR2高表达的肿瘤进展十分重要，破坏Wnt5a-ROR2相互作用可以成为发现抗肿瘤药物的出发点。本项目将阐明ROR2的跨膜信号转导的结构机制以及wnt5a的捕获受体sFRPs或sizzled的结构功能关系，以此指导ROR2单克隆抗体的制备和wnt5a捕捉受体的分子定向进化，从而发现能抑制Wnt5a-ROR2信号轴的蛋白质类候选药物，并在细胞水平和动物水平上评价它们抑制ROR2高表达肿瘤细胞增殖、侵润、转移的药效，在结构和分子水平上阐明它们的作用机制。当前，我们获得了22株抗ROR2的单克隆抗体；解析了wnt5a的捕获受体sizzled的晶体结构，该结构提示去除NTR结构域将有助于获得Wnt5a高亲和力的捕获受体，这些进展说明项目具有可行性。

Receptor tyrosine kinases (RTKs) are a type of practically approved drug targets with high druggablity. ROR2, an atypical RTK, is essentially not expressed in adult tissues, but highly expressed in tumor tissues from an increasingly long list of cancers such as osteosarcoma, pancreatic ductal adenocarcinoma and cervical cancer, which suggests that ROR2 is a potentially high value drug target for developing anticancer therapeutics. Since ROR2 is a pseudokinase without intracellular kinase activity, the traditional strategy of screening small-molecule kinase inhibitors is no longer applied for ROR2 target validation. Wnt5a-ROR2 signal axis is critical for progression of tumors with high ROR2 expression, so the interaction between Wnt5a and ROR2 may be the Achilles‘s heel for anticancer drug development. In this project, we plan to elucidate structural mechanisms of ROR2 transmembrane signaling transduction and structure-function relationships of sFRPs and sizzled, a type of secreted protein called Wnt5a decoy receptors. The structural biology study will facilitate development of ROR2 mAbs and discovery of Wnt5a decoy proteins through directed evolution. At the cellular and animal levels, the resultant ROR2 mAbs and Wnt5a decoy proteins will be evaluated for their pharmacological functions of inhibiting proliferation, invasion and metastasis of cancer cells with high expression of ROR2. Also, at the structural and molecular levels, we are intended to investigate action mechanisms of these protein drug candidates and provide atomic details for interaction between them and targets. Currently, we have developed 22 anti-ROR2 mAbs and solved the crystal structure of sizzled. The crystal structure implicates that elimination of the NTR domain would be helpful for enhancing Wnt5a binding affinity to this family of decoy receptors. Our progress in this project has proved that our research plan is feasible.