Chemically Programmed Bispecific Antibodies for Cancer Therapy

描述（由申请人提供）：双特异性抗体（biAb）通过一个臂与肿瘤细胞结合并通过另一个臂同时募集和激活肿瘤细胞裂解内源性免疫细胞来发挥细胞毒性，是用于癌症治疗的新一代抗体药物的新兴类别。我们的研究团队将开发和提供概念上新颖的化学程序化biAb，其识别具有可变小分子组分的肿瘤细胞，并招募和激活具有通用抗体组分的T细胞和NK细胞。化学程序化的biAb比常规的biAb更通用，因为它们仅需要克隆、表达和纯化单个蛋白质。此外，为了靶向各种不同的肿瘤细胞表面抗原，化学编程的biAb可以利用来自化学文库或基于结构的设计活动的大量小分子，将免疫学和化学的进展联系起来，以造福癌症患者。该研究将严格测试化学编程的biAb可以招募和激活T细胞和NK细胞的假设，这些细胞可以选择性地和有效地杀死体内肿瘤细胞。具体来说，我们将开发和提供两种完全不同分子形式的通用抗体组分，然后对biAb进行化学编程，以选择性靶向叶酸受体1（FOLR 1）。选择FOLR 1作为原型，因为这种肿瘤细胞表面抗原是卵巢癌和肺癌以及其他破坏性实体恶性肿瘤中小分子和单克隆抗体的临床研究靶标。将被询问的两种分子形式是基于我们为抗体的分子定义的化学编程开发的反应性硒代半胱氨酸（Sec）和反应性赖氨酸（Lys）技术。在目标1中，我们将基于具有工程化C-末端Sec的Fab形式的单个抗体模块生成并验证化学程序化（FOLR 1 x CD 3）和（FOLR 1 x NKG 2D）biAb。在目标2中，我们将基于DART（双亲和再靶向）形式的双抗体模块生成并验证化学程序化（FOLR 1 x CD 3）和（FOLR 1 x NKG 2D）biAb，其显示单个反应性Lys残基。将分析并比较这两种分子形式的化学程序化biAb募集和激活T细胞（通过CD 3）和NK细胞（通过NKG 2D）的能力，以直接杀死表达FOLR 1的肿瘤细胞。最后，在目标3中，我们将测试我们的化学程序化的biAb在移植有人效应细胞和靶细胞的免疫受损小鼠中的功效和安全性。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.