Re-purposing Oncolytic Virotherapy to Re-invigorate CAR T Cell Therapy for Solid Tumors.

项目摘要 CAR T细胞疗法针对实体瘤的功效受到缺乏体内扩增、低水平免疫抑制和低水平免疫抑制的限制。 肿瘤运输、功能性/持久性差以及肿瘤微环境（TME）中的抑制。 常规制备的CAR T细胞不能保持足够的分化可塑性以经历自然分化。 T细胞增殖/分化/体内持久性的途径，用于持续有效的细胞毒性抗肿瘤 活动溶瘤病毒（OV）选择性地在肿瘤细胞中复制，产生高度炎症性TME 其可以增强CAR T细胞向实体瘤的募集并在实体瘤内发挥功能。我们的目标是开发一部小说 溶瘤病毒疗法可用作有效的免疫佐剂，以改善肿瘤细胞的免疫功能。 CAR T细胞疗法对实体瘤的功效。 通过在CAR T细胞上离体加载OV，我们在肿瘤治疗中实现了非常显著的改善。 与单独的病毒或CAR T细胞相比。用完全全身递送的CAR T和VSV治疗的小鼠 开发了一群具有T细胞受体（TCR）特异性的CD8 + CAR T细胞， H2Kb VSV N52 - 59表位，其在体内选择性扩增至非常高的频率。这一人口 双特异性（DS）（病毒特异性和CAR T抗原特异性）记忆样（TM）CAR T细胞1）。坚持 小鼠比常规CAR T长得多，2）。抗肿瘤作用明显增强; 3）。 可以通过用同源病毒进行二次全身加强而在体内快速再活化以对抗肿瘤， 导致肿瘤的长期治愈。用两种不同的OV（VSV和OV）观察这些治疗效果。 呼肠孤病毒）和穿过肿瘤部位（皮下和颅内）。因此，我们在这里提出一个完全 扩大针对实体瘤的CAR T细胞治疗范围的新方法，其中双重特异性CAR T 通过使用共同施用的OV诱导具有改善的抗肿瘤活性的细胞， 重演导致最佳（CAR）T细胞活化、增殖和增殖的生理途径， 在体内响应病毒感染的分化。 我们制定了三个具体的目标：1）确定TCR接合的分子机制， DS CAR T细胞的数量决定了它们的表型、改善的持久性和功能; 2）为了在体内产生 扩增的DS CAR T细胞群体具有针对肿瘤相关或病毒回忆的TCR特异性， 抗原，并确定其对已建立的肿瘤的治疗活性; 3）在体内优化 通过新的加强和休息策略，DS CAR T细胞的扩增、持久性/寿命和再活化 靶向TCR、CAR或两者。这将导致执行全面系统的议定书， CAR T细胞与OV的组合，其不需要任何接近肿瘤的途径。

PROJECT SUMMARY Efficacy of CAR T cell therapies against solid tumors has been limited by a lack of expansion in vivo, low levels of tumor trafficking, poor functionality/persistence and by suppression in the tumor micro-environment (TME). Conventionally prepared CAR T cells are unable to retain sufficient differentiational plasticity to undergo natural pathways of T cell proliferation/differentiation/persistence in vivo for sustained, effective cytotoxic anti-tumor activity. Oncolytic viruses (OV) selectively replicate in tumor cells to generate a highly inflammatory TME which may enhance CAR T cell recruitment to, and function within, solid tumors. Our goal is to develop a novel regimen by which oncolytic virotherapy can be used as a potent immunological adjuvant to improve the efficacy of CAR T cell therapy against solid tumors. By loading the OV on the CAR T cells ex vivo, we achieved highly significant improvements in tumor therapy compared to virus or CAR T cells alone. Mice treated with completely systemically delivered CAR T and VSV developed a population of CD8+ CAR T cells with T Cell Receptor (TCR) specificity for the immunodominant H2Kb VSV N52-59 epitope of VSV which selectively expanded in vivo to very high frequency. This population of dual-specific (DS) (virus-specific and CAR T antigen-specific) memory-like (TM) CAR T cells 1). persisted in mice for much longer than conventional CAR T, 2). was significantly more functional against tumor, and 3). could be rapidly re-activated in vivo against tumor by a secondary systemic boost with homologous virus, resulting in long-term tumor cures. These therapeutic effects were observed with two different OV (VSV and reovirus) and across tumor sites (subcutaneous and intra-cranial). Therefore, here we propose a completely novel approach to expand the scope of CAR T cell therapy against solid tumors in which dual specific CAR T cells with improved activity against tumors are generated by using co-administered OV to induce a recapitulation of the physiological pathways that lead to optimal (CAR) T cell activation, proliferation and differentiation in vivo in response to virus infection. We have formulated three Specific Aims: 1) To define the molecular mechanisms by which TCR engagement of DS CAR T cells determines their phenotype, improved persistence and function; 2) To generate in vivo expanded populations of DS CAR T cells with TCR specificity against either tumor associated, or viral recall, antigens and to determine their therapeutic activity against established tumors; 3) To optimize in vivo expansion, persistence/longevity and re-activation of DS CAR T cells through novel boost and rest strategies targeting either the TCR, CAR or both. This will lead to implementation of fully systemic protocols for the combination of CAR T cells with OV which do not require any access to tumors.