基于S-层蛋白表面展示技术研究多靶位纳米抗体增强肿瘤靶向的作用机制

肿瘤发展有赖于泛素连接酶Trim39、细胞程序性死亡蛋白PD-L1、血管内皮生长因子受体VEGFR-1/2等一系列通路和关键蛋白。然而，目前的单靶位药物往往面临靶标突变等旁路途径产生的肿瘤耐药性问题。最近研究表明双靶位抗体药物可加强抑制肿瘤旁路机制。基于芽胞杆菌S-层蛋白表面展示，我们已开展了Trim39抗体重链可变区VH封闭肿瘤细胞内Trim39靶蛋白的研究，以此为基础，本项目将通过S-层蛋白表面展示等基因工程和材料化学方法将肿瘤关键蛋白的单链抗体融合或嵌合构建为多靶位纳米抗体，同时对其优化，进而制备多靶位药物传递体系。通过单链抗体、多靶位纳米抗体对抗原的亲和作用及其构象研究、多靶位药物体系靶向肿瘤治疗研究，探明多靶位纳米抗体增强肿瘤靶向机理，为工程抗体多靶向优化策略及靶向机制研究提供科学方法和理论依据。

Tumor development depends on a series of pathways and key proteins such as ubiquitin ligase Trim39, programmed cell death protein PD-L1, and vascular endothelial growth factor receptors VEGFR-1/2. However, current single-target drugs are frequently frustrated by tumor resistance generated by target mutations and other alternative pathways. It has been reported that dual-targeted antibody drugs can enhance inhibition of the tumor bypass mechanism. Based on Bacillus S-layer protein surface display technology, we have developed Trim39 antibody heavy chain variable region VH as an intrabody to block the target intracellular Trim39 protein in tumor cells, and on this base, the current project will fuse or couple the single chain antibodies to multi-targeted nanobodies with specificity for several key tumor specific proteins, using genetic engineering (such as the S-layer protein surface display) and material chemical methods, along with optimization, and then, drug delivery systems targeting multiple sites will be constructed. Through study of the affinity of the single chain antibodies or multi-targeted nano-antibodies (nanobodies) to the antigens and related conformation informatino, and through study of tumor suppression with multi-targeted drug systems, the mechanism of enhancing tumor target efficacy using the multi-targeted nanobodies will be proven, and a scientific method and a theoretical basis will be provided for optimization of engineered multi-target antibodies and study of their target mechanisms.