三阴性乳腺癌（TNBC）是恶性程度很高的肿瘤且缺乏有效的靶向治疗手段。研究表明，TNBC中频繁发生Wnt通路的异常活化，Wnt受体之一Fzd7在TNBC中显著上调，并通过经典Wnt通路调节肿瘤的发生发展。本项目拟用噬菌体展示技术获得抗Fzd7的单链抗体，并提出一种抗Fzd7 scFv与MICA融合分子的设计。机体免疫监视作用的重要机制是NK细胞借NKG2D与肿瘤细胞表面MICA作用而发挥杀伤效应。该设计既可通过scFv部分精准靶向肿瘤组织，又可通过抗体融合的MICA经MICA-NKG2D途径招募、活化NK细胞，强化机体的免疫监视作用。基于此融合抗体的构建表达，我们监测其与Fzd7/NKG2D作用的动力学过程并验证其体内靶向性；研究其抗肿瘤活性及机制，并通过对比scFv突出MICA部分的免疫调节活性。望通过本设计为TNBC的临床治疗提供安全有效的候选方案。

Triple negative breast cancer (TNBC) is one of the most difficult malignancy to treat due to a lack of targeted therapy. Studies have demonstrated that activation of Wnt/β-catenin signaling is preferentially found in TNBC. It was recently discovered that Fzd7 (receptor of Wnt) was up-regulated in TNBC and TNBC-derived cell lines, and that Fzd7 modulated TNBC tumorigenesis through the canonical Wnt signaling pathway. Here, we intend to obtain an anti-Fzd7 scFv through the phage display technology, and propose a design of a novel antibody fusion protein (anti-Fzd7-MICA) which consists of an anti-Fzd7 scFv and MICA. NKG2D-mediated recognition of malignant cells by cytotoxic lymphocytes is enabled through MICA (activating NKG2D receptor). We postulate that the particular antibody fusion protein will target the tumor tissue precisely to block the Wnt pathway via scFv section, further recruit and active the NK cells through MICA-NKG2D pathway to strengthen the immunosurveillance. On the basis of the construction and expression of anti-Fzd7-MICA, we will monitor the kinetic process of the fusion to Fzd7/NKG2D and verify the targeting effect in vivo. The antineoplastic activity and mechanism of the fusion will be studied through a series of experiments in vitro and in vivo, and the immunoregulatory activity of MICA section will be highlighted by comparison with anti-Fzd7 scFv. The novel design hopes to provide a safe and effective candidate for the clinical treatment of TNBC.