Chemically Programmed Bispecific Antibodies for Cancer Therapy

描述(申请人提供)：双特异性抗体(BiAbs)通过一只手臂与肿瘤细胞结合，另一只手臂同时招募和激活裂解肿瘤细胞的内源性免疫细胞来发挥细胞毒作用，是一种新兴的用于癌症治疗的下一代抗体药物。我们的研究团队将开发和提供概念上新颖的化学编程BiAbs，它可以识别具有可变小分子成分的肿瘤细胞，并利用通用抗体成分招募和激活T细胞和NK细胞。化学编程的双抗体比传统的双抗体用途更广，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步联系起来，使癌症患者受益。这项拟议的研究将严格测试这一假设，即化学编程的双抗可以招募和激活T细胞和NK细胞，从而在体内选择性和有效地杀死肿瘤细胞。具体地说，我们将开发和提供两种完全不同的分子形式的通用抗体成分，然后对BiAbs进行化学编程，以选择性地靶向叶酸受体1(FOLR1)。FOLR1被选为一个原型，因为这种肿瘤细胞表面抗原是卵巢癌、肺癌和其他毁灭性实体恶性肿瘤中小分子和单抗的临床研究靶点。将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而开发的反应性硒半胱氨酸(SEC)和反应性赖氨酸(Lys)技术。在目标1中，我们将基于Fab格式的单个抗体模块和经过设计的C-末端SEC来生成和验证化学编程的(FOLR1 X CD3)和(FOLR1 X NKG2D)双抗。在目标2中，我们将基于显示单个反应性赖氨酸残基的DART(双亲和重靶向)格式的双抗体模块，生成并验证化学编程的(FOLR1 X CD3)和(FOLR1 X NKG2D)双抗。这两种分子形式的化学编程双抗将被分析和比较它们招募和激活T细胞(通过CD3)和NK细胞(通过NKG2D)直接杀伤表达FOLR1的肿瘤细胞的能力。最后，在目标3中，我们将在植入人类效应器和靶细胞的免疫缺陷小鼠身上测试我们的化学编程BiAbs的有效性和安全性。总而言之，我们的活动将为下一代抗体药物提供新的概念和结构，这些药物明确地为癌症治疗中的广泛用途而设计。

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.