Novel Single Domain Antibodies with Multivalency and Multispecificity

描述（由申请人提供）：ErbB/HER受体在调节细胞增殖、分化、运动和凋亡的信号传播中发挥重要作用。值得注意的是，ErbB/HER受体酪氨酸激酶家族及其配体的异常调控在许多人类肿瘤中都很常见。事实上，EGFR、HER2和HER3已被诊断和治疗证实为多种人类恶性肿瘤的靶点，如肺癌、结直肠癌、乳腺癌、头颈癌、胃癌和胰腺癌。因此，综合靶向ErbB/HER家族成员的新型蛋白生物药物在不同类型癌症的靶向诊断和治疗中具有重要的应用价值。该项目解决了开发具有成本效益的靶向配体的关键需求，这些配体可以识别和结合HER家族成员，具有所需的亲切性和多特异性。该项目旨在使用一种强大的体外蛋白选择方法，称为mRNA显示，从具有异常高多样性的人类SDA结构域文库中进化出具有人类起源的单域抗体（SDAs），分别与EFRG， HER2或HER3的细胞外结构域紧密特异性结合。由此产生的单体sda将作为产生异二聚体sda的基础，这些异二聚体sda结合在两个不重叠的表位上，具有协同亲和力效应。此外，我们将开发一种高效和通用的自组装系统，允许可逆和可控地将her结合的SDAs加载到纳米颗粒上，以获得所需的多特异性。由此产生的SDAs将具有许多优点，包括高靶向结合亲和力，易于实现所需的亲和性，多价性和多特异性，由于人类来源而具有最小的免疫原性，小尺寸以更好地穿透组织，此外由于在细菌中的高表达水平而显着降低了制造成本。这些sda的简单性和稳定性也极大地促进了它们与各种纳米颗粒的结合，用于翻译应用。通过靶向递送含有sirna的纳米颗粒来检测PDAC异种移植动物模型中产生的SDAs，这些sirna针对PDAC肿瘤发生和转移的几个重要转移标志基因。该项目的成功将导致开发具有成本效益的靶向生物制药，用于癌症诊断和治疗。

DESCRIPTION (provided by applicant): ErbB/HER receptors play essential roles in propagating signals that regulate cell proliferation, differentiation, motility, and apoptosis. Significantly, aberrant regulation of the ErbB/HER family of receptor tyrosine kinases and their ligands is a common occurrence in many human tumors. Indeed, EGFR, HER2, and HER3 have been diagnostically and therapeutically validated as targets in a wide variety of human malignancies such as lung, colorectal, breast, head and neck, gastric and pancreatic cancers. Therefore, novel protein biopharmaceuticals that comprehensively target ErbB/HER family members could have significant applications in targeted diagnosis and therapy of different types of cancer. This project addresses a critical need for developing cost-effective targeting ligands that recognize and bind HER family members with desired avidity and multispecificity. The project is directed at using a powerful in vitro protein selection method called mRNA display to evolve single domain antibodies (SDAs) with human origin that tightly and specifically bind to the extracellular domain of EFRG, HER2 or HER3, respectively, from a human SDA domain library with an unusually high diversity. The resulting monomeric SDAs will be used as the basis for the generation of heterodimeric SDAs that bind to a HER member of interest at two nonoverlapping epitopes with synergistic avidity effect. In addition, we will develop an efficient and universal self-assembly system that allows for reversible and controllable loading of HER-binding SDAs to nanoparticles to acquire desired multispecificity. The resulting SDAs would have a number of advantages, including high target-binding affinity, ease to achieve desired avidity, multivalency and multispecificity, minimal immunogenicity due to human origin, small size for better tissue penetration, in addition to significantly reduced manufacturing costs due to high expression levels in bacteria. The simplicity and stability of these SDAs also greatly facilitate their conjugation with various nanoparticles for translational applications. The resulting SDAs will be examined in vivo in pancreatic ductal adenocarcinoma (PDAC) xenograft animal models by targeted delivery of nanoparticles containing siRNAs against several metastasis signature genes that are important for PDAC tumorigenesis and metastasis. The success of the project will lead to the development of cost-effective, targeted biopharmaceuticals for cancer diagnosis and therapy.