Chemically Programmed Bispecific Antibodies for Cancer Therapy

描述（由申请人提供）：双特异性抗体（biAbs）是一种新兴的用于癌症治疗的下一代抗体药物，它通过单臂与肿瘤细胞结合，同时用另一只手臂招募和激活肿瘤细胞裂解内源性免疫细胞来发挥细胞毒性。我们的研究团队将开发和交付概念新颖的化学编程biAbs，该biAbs识别具有可变小分子成分的肿瘤细胞，并招募和激活具有通用抗体成分的T细胞和NK细胞。化学编程的biAbs比传统的biAbs更通用，因为它们只需要克隆、表达和纯化单个蛋白质。此外，为了针对各种不同的肿瘤细胞表面抗原，化学编程的biAbs可以利用来自化学文库或基于结构的设计活动的丰富小分子，将免疫学和化学的进步联系起来，为癌症患者带来好处。该研究将严格验证化学编程的biAbs可以招募和激活T细胞和NK细胞，从而选择性和有效地杀死体内肿瘤细胞的假设。具体来说，我们将开发和递送两种完全不同的分子格式的通用抗体成分，然后化学编程biAbs选择性靶向叶酸受体1 （FOLR1）。之所以选择FOLR1作为原型，是因为这种肿瘤细胞表面抗原是卵巢癌、肺癌和其他破坏性实体恶性肿瘤小分子和单克隆抗体的临床研究靶点。将被询问的两种分子格式是基于反应性硒半胱氨酸（Sec）和反应性赖氨酸（Lys）技术，我们为抗体的分子定义化学编程开发了这两种技术。在Aim 1中，我们将生成和验证基于Fab格式的单个抗体模块的化学编程（FOLR1 x CD3）和（FOLR1 x NKG2D） biAbs，带有工程c端Sec。在Aim 2中，我们将生成和验证基于DART（双亲和重靶向）格式的双抗体模块的化学编程（FOLR1 x CD3）和（FOLR1 x NKG2D） biAbs，显示单个活性赖氨酸残基。这两种分子格式的化学编程biAbs将被分析和比较，以确定它们招募和激活T细胞（通过CD3）和NK细胞（通过NKG2D）的能力，从而直接杀死表达folr1的肿瘤细胞。最后，在Aim 3中，我们将在植入人类效应细胞和靶细胞的免疫功能低下小鼠中测试化学编程的biAbs的有效性和安全性。总的来说，我们的活动将为下一代抗体药物提供新的概念和结构，这些药物明确设计用于癌症治疗的广泛用途。

DESCRIPTION (provided by applicant): Bispecific antibodies (biAbs) that exert cytotoxicity by binding to tumor cells with one arm and by simultaneously recruiting and activating tumor cell-lysing endogenous immune cells with the other arm are an emerging category of next-generation antibody drugs for cancer therapy. Our research team will develop and deliver conceptually novel chemically programmed biAbs that recognize tumor cells with a variable small molecule component and that recruit and activate T cells and NK cells with a generic antibody component. Chemically programmed biAbs are more versatile than conventional biAbs as they only require the cloning, expression, and purification of a single protein. Further, to target a variety of different tumor cell surface antigens, chemically programmed biAbs can make use of a wealth of small molecules derived from chemical libraries or from structure-based design campaigns, linking advances in both immunology and chemistry for the benefit of cancer patients. The proposed study will rigorously test the hypothesis that chemically programmed biAbs can recruit and activate T cells and NK cells that selectively and potently kill tumor cells n vivo. Specifically, we will develop and deliver two entirely different molecular formats of the generic antibody component and then chemically program biAbs to selectively target folate receptor 1 (FOLR1). FOLR1 was chosen as a prototype as this tumor cell surface antigen is a clinically investigated target for both small molecules and monoclonal antibodies in ovarian and lung cancer and in other devastating solid malignancies. The two molecular formats that will be interrogated are based on the reactive selenocysteine (Sec) and the reactive lysine (Lys) technologies that we developed for molecularly defined chemical programming of antibodies. In Aim 1 we will generate and validate chemically programmed (FOLR1 x CD3) and (FOLR1 x NKG2D) biAbs based on a single antibody module in Fab format with an engineered C-terminal Sec. In Aim 2 we will generate and validate chemically programmed (FOLR1 x CD3) and (FOLR1 x NKG2D) biAbs based on a dual antibody module in DART (Dual-Affinity Re-Targeting) format that displays a single reactive Lys residue. Chemically programmed biAbs in these two molecular formats will be analyzed and compared for their ability to recruit and activate T cells (via CD3) and NK cells (via NKG2D) to direct killing of FOLR1-expressing tumor cells. Finally, in Aim 3, we will test the efficacy and safety of our chemically programmed biAbs in immunocompromised mice engrafted with both human effector and target cells. Collectively, our campaign will deliver both novel concepts and constructs for next-generation antibody drugs that are explicitly designed for broad utility in cancer therapy.