Translating Autoantibodies Into Chimeric Antigen Receptor-T cell Therapy for Small Cell Lung Cancer

摘要 在过去的30年里，小细胞肺癌(SCLC)的5年生存率一直不到7%，尽管 增加免疫检查点抑制剂作为治疗选择。免疫检查点抑制剂等疗法 先前的研究表明，旨在重新启动免疫反应的目的可能不会对小细胞肺癌成功 MHC分子表达下调，PD-L1表达降低，免疫浸润受限。然而，SCLC是 通常与自身抗体驱动的副肿瘤综合征有关，为 小细胞肺癌的免疫原性。我们建议嵌合抗原受体T细胞(CAR-TS)作为一种新的治疗方法 克服内源性免疫障碍的小细胞肺癌免疫疗法。Car-T是综合的 将抗体配体结合域与共刺激成分融合在一起，激活T细胞 细胞表面抗原的结合，并在白血病、淋巴瘤和多发性硬化方面取得了相当大的成功。 骨髓瘤。小细胞肺癌的微环境在表型上更接近CAR-T反应性淋巴瘤 到目前为止，Car-t治疗实体肿瘤的成功有限。CAR-T细胞在许多实体瘤中面临的挑战 是识别肿瘤特异性的靶抗原。我们鉴定了13个新的细胞表面抗原 这里将优先考虑3例小细胞肺癌高发病例。这些抗原中的每一种都有翻译后 在很高比例的小细胞肺癌病例中，作为新抗原并导致自身抗体产生的修饰。 我们将从小细胞肺癌患者来源的B细胞中捕获这些新的抗原自身抗体，并对肿瘤特异性进行测序 结合序列，并设计和测试由单链可变片段(ScFv)构建的汽车。 从小细胞肺癌患者中分离自身抗体以检测肿瘤特异性新抗原有三方面的好处：1. 已确定的抗原已被证明具有免疫原性；2.这些人的可变区 自身抗体可以被直接工程到CAR-T细胞的配基结合域；以及3.自身抗体 可以在患者的血液中检测到，并作为组织替代生物标志物来指导CAR-T细胞靶点 选择。我们开发的CAR-T细胞将在多个临床前模型中进行严格测试，以解决 互补但不重叠的治疗障碍。这些测试包括检测CAR-T细胞肿瘤的渗透， 在基因多样化的小细胞肺癌患者来源的异种移植物文库中的有效性和毒性，然后进行鉴定 免疫活性Rb/P53基因工程小鼠克服免疫抑制机制的研究 模特。我们的专家团队在肺癌、自身抗体生物标志物、免疫学和CAR-T细胞方面做得很好 有能力执行小细胞肺癌急需的新型免疫疗法的开发。

Abstract For the last 30 years, the 5-year survival rate of small cell lung cancer (SCLC) has been less than 7% despite the addition of immune checkpoint inhibitors as treatment options. Therapies like immune checkpoint inhibitors that aim to reengage an immune response may not succeed for SCLC as previous studies have shown downregulation of MHC molecules, low PD-L1 expression and limited immune infiltration. However, SCLC is often associated with autoantibody-driven Paraneoplastic Syndromes, providing evidence for the immunogenicity of SCLC. We propose that chimeric antigen receptor T cells (CAR-Ts) as a novel approach for SCLC immunotherapy that overcomes impediments to endogenous immunity. CAR-Ts are synthetically engineered to fuse antibody ligand binding domains with costimulatory components that activate T cells after engagement of cell surface antigens, and have had considerable success in leukemia, lymphoma, and multiple myeloma. The microenvironment of SCLC is phenotypically closer to CAR-T responsive lymphoma than many solid tumors where CAR-Ts have thus far had limited success. A challenge for CAR-T cells in many solid tumors is the identification of target antigens that are tumor-specific. We have identified 13 novel cell surface antigen and here will prioritize 3 with high prevalence in SCLC. Each of these antigens have post-translational modifications that act as neoantigens and lead to autoantibody production in a high percentage of SCLC cases. We will capture these neoantigen-autoantibodies from SCLC patient-derived B cells, sequence the tumor specific binding sequences, and design and test CARs constructed from the single chain variable fragments (scFvs). The benefit of isolating autoantibodies from SCLC patients to detect tumor-specific neoantigens is three-fold: 1. The antigens identified have already proven to be immunogenic; 2. The variable regions of these human autoantibodies can be directly engineered into ligand binding domains of CAR-T cells; and 3. Autoantibodies can be detected in the blood of patients and serve as tissue surrogate biomarkers to guide CAR-T cell target selection. The CAR-T cells we develop will be rigorously tested in multiple preclinical models that address complementary but non-overlapping therapeutic barriers. These include testing CAR-T cell tumor infiltration, efficacy and toxicity in a library of genetically diverse SCLC patient derived xenografts and identifying, then overcoming, immunosuppressive mechanisms in the immune competent Rb/p53 genetically engineered mouse model. Our team of experts in lung cancer, autoantibody biomarkers, immunology and CAR-T cells is well equipped to execute the development of novel immunotherapies that are desperately needed in SCLC.