目前，阻断DLL4/Notch通路抑制肿瘤发生、肿瘤血管生成及肿瘤干细胞增殖成为靶向治疗肿瘤的热点。同时，阻断 VEGF通路抑制血管异常增生亦是肿瘤靶向治疗的重要策略。因此，本项目拟在课题组前期获得的人源化抗DLL4单克隆抗体基础上，首先从全人源噬菌体展示库筛选抗VEGF单链抗体，然后运用本实验室成熟的抗体制备技术获得亲和力高、结构稳定的抗DLL4/抗VEGF双特异性抗体，研究其抗肿瘤活性并用荷瘤小鼠模型及全基因组表达谱芯片结合分子生物学手段探索其对肿瘤血管结构和功能的调控，从抗血管生成和抗肿瘤干细胞两方面研究其抗肿瘤机制。我们预期该双特异性抗体能通过双靶向肿瘤新生血管表面的DLL4与VEGF同时阻断这两条通路从而加强阻断效果，抗肿瘤活性将优于单一的单克隆抗体，并能有效避免或减少肿瘤细胞对单克隆抗体的耐受性，达到更好的治疗效果，同时也为发展我国具有自主知识产权的抗肿瘤抗体药物搭建技术平台。

Currently，blocking DLL4/Notch signal pathway to inhibit tumor develoment, tumor angiogenesis and cancer stem cell self-renewing is a focus on tumor-targetted therapy. Besides, VEGF blockade is also an important way of tumor-targetted therapy by inhibiting abnormal angiogenesis. Therefore, in this project, anti-VEGF single chain antibody will be screened out from the human scFv phage display library, and on the basis of our humanized anti-DLL4 mAb, with the help of our skilled gene engineering antibody preparation technology, the anti-DLL4/anti-VEGF bispecific antibody will be constructed and expressed by eukaryotic system to achieve bispecific antibody with high affinity and stable structure. Then, anti-tumor activity of the bispecific antibody in vitro and in vivo will be studied. Further more, how the bispecific antibody regulates structure and function of tumor angiogenesis will also be studied by tumor-bearing mice models and whole genome expression microarray with the help of up-to-date molecular approaches. The anti-tumor mechanism will be studied by both anti-angiogenesis effect and anti-cancer stem cell effect. We expect the new bispecific antibody can inhibit tumor growth by double targetting both DLL4 and VEGF on surface of tumor angiogenesis, block the two signaling pathways so as to strengthen the blocking effect, has better anti-tumor activity than single monoclonal antibody and can effectively avoid or reduce the tolerance of the tumor cells. It will achieve the purpose of better treatment of tumors. This project aims to provide technological platform for anti-tumor antibody drugs of independent intellectual property rights in China.