Understanding the Behavior of Novel IL13Ralpha2-directed T cell Engager for GBM

胶质母细胞瘤(GBM)仍然是无法治愈的癌症，尽管进行了积极的多模式治疗，但存活率仍然很低。 这可能包括手术、放射、化疗和肿瘤治疗领域。没能改善结果 GBM患者强调了开发新的靶向治疗的迫切需要。双特异性T细胞激活剂(BITES) 蛋白质通过与T细胞和肿瘤的BITT结合促进激活的T细胞对肿瘤细胞的特异性杀伤 细胞。由于这种治疗方法对像GBM这样的实体肿瘤还处于早期开发阶段，我们的 对肿瘤摄取、药代动力学和作用机制的了解有限，这阻碍了合理的 用于评估咬合的临床研究设计。将咬合作为治疗GBM以及其他疾病的一种策略 实体瘤，我们已经设计并鉴定了一种单链抗体(ScFv)，它可以特异性地靶向 IL13Rα2是一种细胞表面受体，表达于基底膜细胞，但不表达于正常脑细胞。我们已经产生了 并测试了几种针对人或小鼠CD3 T细胞的BITE分子配置。我们的数据显示 IL 13Rα2 Bit I)与基底膜细胞上的人IL 13Rα2特异性结合，II)特异性激活T细胞 BIT分子与这些表达IL13Rα2的基底膜细胞的结合，III)介导T细胞依赖 在PM浓度下对GBM细胞的杀伤，以及iv)显著提高同基因小鼠的存活率 颅内基底膜肿瘤。成像数据显示，咬伤可以穿透血液-肿瘤屏障，而且 激活T细胞。初步结果还表明，咬合作用的机制并不局限于直接致死。 激活的T细胞对胶质瘤细胞的影响，但也通过激活额外的宿主影响肿瘤微环境 免疫功能。基于我们强大的临床前数据，我们假设(I)系统地获得GBM 递送的BITES是一个依赖于T细胞的过程，(Ii)BITE主动地调节T细胞以及其他 宿主免疫反应分区，导致在临床前产生强大的抗肿瘤治疗反应 GBM模型。这一假设将在三个具体目标上得到检验。SA1将调查以下各项的依赖关系 IL13Rα2咬合T细胞，促进肿瘤的进入和滞留，肿瘤的摄取和生物分布。高级公务员事务局局长会研究 白介素13Rα2刺激宿主免疫系统产生持久的抗肿瘤免疫的机制。 在SA3中，我们将开发和确定一种使用小鼠和人类GBM模型的咬伤治疗方案 可随后转化为对患者的治疗。在成功完成这些研究后，我们 将获得关于影响BITE抗肿瘤活性的因素的知识。这些研究将提供一个 为今后IL13Rα2 BIT在临床上的应用奠定了坚实的基础，具有广泛的应用前景 适用于其他表达IL13Rα2的恶性肿瘤。

Glioblastoma (GBM) remains incurable cancer with a dismal survival rate despite aggressive multimodal therapy that can include surgery, radiation, chemotherapy, and tumor-treating fields. The failure to improve outcome in GBM patients underscores an urgent need to develop new targeted therapies. Bi-specific T cell engager (BiTEs) proteins promote specific killing of cancer cells by activated T cells via BiTE binding to both T-cells and tumor cells. Because this type of therapy is at an early stage of development for solid tumors such as GBM, our knowledge of tumor uptake, pharmacokinetics, and mechanism of action is limited, which hinders the rational design of clinical studies for evaluating BiTEs. To advance BiTEs as a strategy for treating GBM, as well as other solid tumors, we have engineered and characterized a single-chain antibody (scFv) that specifically targets IL13Rα2, a cell surface receptor that is expressed on GBM cells, but not normal brain cells. We have generated and tested several configurations of BiTE molecules targeting human or murine CD3 T cells. Our data show that the IL13Rα2 BiTE i) binds specifically to human IL13Rα2 on GBM cells, ii) specifically activates T cells upon engagement of the BiTE molecule with these IL13Rα2-expressing GBM cells, iii) mediates T-cell dependent killing of GBM cells at pM concentrations, and iv) significantly improves the survival of mice bearing syngeneic intracranial GBM tumors. Imaging data show that BiTEs penetrate through the blood-tumor barrier and also engage T cells. Preliminary results also suggest that the mechanism of BiTE action is not limited to direct killing of glioma cells by activated T cells but also affects the tumor microenvironment by activating additional host immune function. Based on our robust preclinical data, we hypothesize that (i) GBM access of systemically delivered BiTEs is a T-cell-dependent process, and (ii) BiTEs actively modulate T cell as well as other host immune response compartments, leading to a robust anti-tumor therapeutic response in preclinical GBM models. This hypothesis will be tested in three Specific Aims. SA1 will investigate the dependencies of IL13Rα2 BiTE on T cells for tumor access and retention, tumor uptake, and biodistribution. SA2 will study the mechanism by which IL13Rα2 BiTE primes the host immune system to generate durable anti-tumor immunity. In SA3, we will develop and identify a BiTE treatment regimen using murine and human models of GBM that could subsequently be translated into a therapy for patients. Upon successful completion of these studies, we will acquire knowledge regarding factors that influence BiTE anti-tumor activity. These studies will provide a strong foundation for future clinical application of IL13Rα2 BiTE for GBM treatment and could be broadly applicable to other IL13Rα2-expressing malignancies.