Novel Strategies to Treat Diffuse Midline Glioma with CAR T Cell Therapy

项目摘要 尽管嵌合抗原受体（CAR）T细胞在血液学环境中已经非常成功， 对许多实体瘤适应症的真正肿瘤特异性抗原的鉴定限制了广泛的应用。两 已经考虑了用于弥漫性中线胶质瘤H3 K27 M突变型肿瘤的靶点（先前为弥漫性固有型 脑桥胶质瘤（DIPG）），但由于两者均不限于肿瘤组织，因此存在安全性问题 存在靶向、非肿瘤毒性。此外，辅助治疗意味着增强CAR T功能， 以克服与实体瘤相关的一系列免疫抑制机制， 微环境也有可能加剧这一问题。我们的团队进行了广泛的 溶瘤病毒的临床前表征，并已证明它们是一种非常有效的 用于治疗癌症的免疫抑制剂。我们建议利用肿瘤嗜性24 用溶瘤腺病毒递送CAR靶标沿着CD 40 L。我们的初步数据表明， Ad CD 24-CD 40 L作为单一疗法在GL 261神经胶质瘤模型中提供了显著的治疗优势，并且 此外，可以在概念验证组合环境中增强CD 19 CAR T疗法， B16-CD 19肿瘤。该提案的目标是开发一种双重治疗方法， 肿瘤细胞病毒溶瘤和CAR T细胞溶解，通过病毒介导的增强CAR T细胞募集/激活 炎症，以及重要的是，CD 40 L介导的内源性抗原呈递细胞B细胞的动员 和T细胞。我们将设计一种溶瘤载体，使用E.大肠杆菌DHFR 去稳定化结构域和细胞内截短的信号死亡EGFRvIII分子， 与安全性测试的EGFRvIII CAR T细胞（Aim 1）结合。OV-CAR T的安全性和有效性 方法将在DIPG的基因工程免疫活性模型中进行评估（目的2）。这个项目 有望为CD 40 L如何动员内源性B细胞和T细胞应答提供新的见解 支持CAR T疗法总之，我们希望利用设计者溶瘤病毒的特性， 更广泛地使CAR T细胞疗法在实体瘤中的使用成为可能，特别是将现有的安全性 测试的免疫疗法，以一个毁灭性的和紧迫的未满足的临床需求。

PROJECT SUMMARY Although chimeric antigen receptor (CAR) T cells have been remarkably successful in the hematologic setting, identification of truly tumor specific antigens for many solid tumor indications has limited broad translation. Two targets have been considered for Diffuse Midline Glioma H3 K27M-mutant tumors (previously Diffuse Intrinsic Pontine Glioma (DIPG)), however as neither are exclusively restricted to neoplastic tissue, safety concerns exist with respect to on-target, off-tumor toxicity. Moreover, ancillary treatment meant to boost CAR T function to overcome a constellation of immune suppressive mechanisms associated with the solid tumor microenvironment also has the potential to exacerbate the problem. Our group has conducted extensive preclinical characterization of oncolytic viruses and has demonstrated them to be a highly effective immunotherapeutic agents for the treatment of cancer. We propose to leverage the tumor tropism of ∆24 oncolytic adenovirus to deliver a CAR target along with CD40L. Our preliminary data indicates that oncolytic Ad∆24-CD40L provides a significant therapeutic advantage in a GL261 glioma model as a monotherapy, and further, can potentiate CD19 CAR T therapy in a proof of concept combination setting against subcutaneous B16-CD19 tumors. The goal of this proposal is to develop a dual therapy approach which builds on direct tumor cell viral oncolysis and CAR T cytolysis, enhanced CAR T cell recruitment/activation by virus-mediated inflammation, and importantly, CD40L-mediated mobilization of endogenous antigen presenting cells, B cells and T cells. We will engineer an oncolytic vector to deliver titratable levels of CD40L using the E. coli DHFR destabilizing domain, and an intracellularly truncated signaling-dead EGFRvIII molecule to be used in conjunction with safety tested EGFRvIII CAR T cells (Aim1). The safety and efficacy of the OV-CAR T approach will be evaluated in a genetically engineered immunocompetent model of DIPG (Aim 2). This project is expected to provide novel insight into how CD40L can mobilize an endogenous B cell and T cell response and support CAR T therapy. Together, we hope to capitalize on the properties of designer oncolytic viruses to more broadly enable the use of CAR T cell therapy in solid tumors, and in particular apply existing safety tested immunotherapies to a devastating and urgent unmet clinical need.