Assessing resistance mechanisms in synNotch-CAR T cell-mediated glioblastoma therapy and evaluation of potential mitigation strategies

胶质母细胞瘤（GBM）是最常见的原发性恶性脑肿瘤，中位总生存期不到2年，复发率接近100%。因此，迫切需要新的治疗策略。嵌合抗原受体T细胞（CAR - T）治疗是有希望的，但一些挑战，如缺乏理想的靶抗原，T细胞耗竭和肿瘤诱导的免疫抑制必须解决。最近，人们发现Notch（1型跨膜蛋白）的嵌合形式可以作为发展新的细胞-细胞接触信号通路（Synthetic Notch“synNotch”）的通用平台。这使得使用合成Notch受体的T细胞能够表现出定制的治疗反应程序。基于“启动和杀死”策略的新一代创新T细胞回路已经开发出来。在这种策略中，仅在脑或GBM细胞上表达的引物抗原被synNotch受体识别，从而诱导CAR的表达（synNotch-CAR=SYNC）。这提供了安全靶向低特异性GBM抗原的可能性，并且还与体内优秀的T细胞持久性有关。尽管这种新方法看起来很有希望，但目前尚不清楚SYNC T细胞在完整免疫系统中的工作效率。最近的研究表明，抗活性免疫调节分子如程序性死亡配体1 （PD-L1）和转化生长因子ß1 （TGF-β1）似乎在肿瘤诱导的免疫抑制中起关键作用。因此，现在需要将同步t细胞疗法与在完整免疫系统中阻断这些分子相结合的研究。本研究的目的是探讨SYNC T细胞疗法对低免疫原性SB28小鼠胶质瘤细胞系中表达egfrviii的免疫活性C57BL/6小鼠的潜在耐药机制。冈田实验室开发的B-SYNC T细胞将用于治疗。这些细胞被cns特异性抗原Brevican引物，并在激活后表达抗egfrviii CAR。将研究B-SYNC单独治疗和联合静脉输注针对PD-1或TGF-ß1的单克隆抗体的疗效。作为次要目标，我还将确定SYNC T细胞本身直接表达的抗pd -1或TGF-ß1是否可以克服潜在的局部免疫抑制，并且当作为额外的有效载荷整合到synNotch电路中时，是否优于输注抗体。

Glioblastoma (GBM) is the most common primary malignant brain tumor with a median overall survival of less than 2 years and a recurrence rate of nearly 100%. Therefore, new therapeutic strategies are urgently needed. Chimeric antigen receptor T cell (CAR T) therapy is promising, but several challenges such as lack of ideal target antigens, T cell exhaustion, and tumor-induced immunosuppression must be addressed. Recently, it was discovered that chimeric forms of Notch, a type 1 transmembrane protein, can serve as a general platform for the development of new cell-cell contact signaling pathways (Synthetic Notch "synNotch"). This enables the development of T cells that exhibit customized therapeutic response programs using synthetic Notch receptors. A new generation of innovative T cell circuits that recognize glioblastoma cells based on the "prime-and-kill" strategy has been developed. In this strategy, priming antigen expressed exclusively on brain or GBM cells is recognized by the synNotch receptor, thereby inducing the expression of a CAR (synNotch-CAR=SYNC). This offers the possibility of safely targeting low-specificity GBM antigens and is also associated with excellent T cell persistence in vivo. Although this new approach appears promising, it is not yet known how efficiently SYNC T cells work in an intact immune system. Recent studies have shown that counter-active immunoregulatory molecules such as programmed death-ligand 1 (PD-L1) and transforming growth factor ß1 (TGF-β1) appear to play a key role in tumor-induced immunosuppression. Therefore, studies combining SYNC-T cell therapy with blockade of these molecules in an intact immune system are now needed. The aim of this study is to investigate potential resistance mechanisms of SYNC T cell therapy in immunocompetent C57BL/6 mice bearing EGFRvIII-expressing brain tumors of the low-immunogenic SB28 mouse glioma cell line. B-SYNC T cells developed by the Okada laboratory will be used as therapy. These cells are primed by the CNS-specific antigen Brevican and express an anti-EGFRvIII CAR upon activation. The efficacy of B-SYNC therapy alone and in combination with intravenous infusion of monoclonal antibodies directed against PD-1 or TGF-ß1 will be investigated. As a subordinate goal, I will also determine whether anti-PD-1 or TGF-ß1 expression directly by the SYNC T cell itself can overcome potential local immunosuppression and may be superior to infusion of antibodies, when integrated as an additional payload in the synNotch circuit.