Project 1: Active immunotherapy combined with checkpoint modulation for glioblastoma

项目1：主动免疫治疗联合检查点调节治疗胶质母细胞瘤 摘要/摘要 缺乏对胶质母细胞瘤(GBM)患者的有效治疗仍然是一个重大的健康问题 强调需要新的和创新的方法。免疫疗法是一种有吸引力的策略，因为 免疫细胞运输并摧毁大脑中浸润性肿瘤细胞的潜在能力。临床前研究 树突状细胞(DC)接种GBM的临床试验显示了一些有希望的结果，但也有一些 治疗失败。这项研究项目的总体目标是研究免疫机制。 主动免疫治疗后的逃避，并开发合理的免疫治疗策略组合 以克服脑瘤微环境的免疫抑制环境。我们新的初步数据 强烈提示DC疫苗的主动免疫疗法可能会产生促炎肿瘤 诱导免疫抑制抗原提呈细胞(IAPC)迁移的微环境 表达高水平的PD-L1和IL-10。我们发现这些细胞的表型类似于iAPC 主要影响T细胞对慢性病毒感染的反应，并可能起到抵消有效T细胞的作用 DC疫苗通过涉及PDL1/PD-1的机制诱导的应答。此外，对iAPC的抑制 使用抗PD1单抗(Nivolumab，BMS)或CSF-1R的中枢神经系统渗透性抑制剂(PLX-3397，Plexxikon)，在 联合肿瘤裂解液推送的DC疫苗(DC-VAX-L)可显著延长小鼠的存活时间 颅内发育良好的荷瘤动物(I.C.)神经胶质瘤。因此，我们假设在临床上 与胶质母细胞瘤相关的抗肿瘤免疫(GBM)必须有两个细胞成分：1)明显的浸润 肿瘤特异性肿瘤浸润性淋巴细胞(TIL)；2)阻断免疫调节抗原提呈 细胞(IAPC)在肿瘤微环境中发挥作用。因此，我们的假设是，局部细胞 脑肿瘤微环境中iAPC和T淋巴细胞的相互作用是一个关键因素 对胶质母细胞瘤患者免疫治疗效果的影响。更好地了解人类的生物学 这些细胞相互作用将为更有效地诱导治疗性抗肿瘤免疫提供洞察力 对这种致命的脑瘤的反应。在目标1中，我们将研究iAPC限制胶质瘤的机制。 体内外特异性抗肿瘤免疫反应。在目标2中，我们将评估联合 肿瘤裂解物冲击的DC疫苗(诱导T细胞进入肿瘤)免疫检查点抑制 和其他新的免疫调节靶点(阻断iAPC功能)在临床前同基因动物模型中 胶质母细胞瘤，并探索利用一种新型的PET示踪剂作为无创性免疫成像生物标志物 回应。最后，在目标3中，我们将开发和验证预测肿瘤、免疫学和成像 在DCVAX-L/-II期临床试验中登记的复发胶质母细胞瘤患者的反应生物标志物 尼伏卢单抗。这些研究跨越了脑肿瘤免疫治疗的转化性研究的连续过程，并将 可能为开发新的、合理的基于免疫的大脑策略提供了新的信息 肿瘤患者。

Project 1: Active immunotherapy combined with checkpoint modulation for glioblastoma SUMMARY/ABSTRACT The lack of effective treatments for glioblastoma (GBM) patients remains a significant health problem and highlights the need for novel and innovative approaches. Immunotherapy is an appealing strategy because of the potential ability for immune cells to traffic to and destroy infiltrating tumor cells in the brain. Pre-clinical studies and clinical trials of dendritic cell (DC) vaccination for GBM have shown some promising results, but also some treatment failures. The broad overall goals of this research project are to investigate mechanisms of immune evasion following active immunotherapy, and to develop rational combinations of immunotherapeutic strategies to overcome the immunosuppressive milieu of the brain tumor microenvironment. Our new preliminary data strongly suggests that active immunotherapy with DC vaccination may create a pro-inflammatory tumor microenvironment that induces the immigration of immunosuppressive antigen presenting cells (iAPC), which express high levels of PD-L1 and IL-10. We show that these cells are phenotypically similar to the iAPC that dominantly influence the T-cell response to chronic viral infection, and may act to counteract effective T-cell responses induced by DC vaccination via a mechanism involving PDL1/PD-1. Furthermore, inhibition of iAPC using an anti-PD1 mAb (Nivolumab, BMS) or a CNS penetrant inhibitor of CSF-1R (PLX-3397, Plexxikon), in conjunction with tumor lysate-pusled DC vaccination (DC-Vax-L), resulted in significantly prolonged survival in tumor-bearing animals with well-established intracranial (i.c.) gliomas. We therefore postulate that clinically relevant anti-tumor immunity to glioblastoma (GBM) must have two cellular components: 1) significant infiltration of tumor-specific tumor-infiltrating lymphocytes (TIL); and 2) blockade of immune-regulatory antigen presenting cell (iAPC) function within the tumor microenvironment. As such, our hypothesis is that the local cellular interactions between iAPC and T lymphocytes within the brain tumor microenvironment is a critical factor influencing the efficacy of immunotherapies in glioblastoma patients. A better understanding of the biology of these cellular interactions will provide insight into more effective ways to induce therapeutic anti-tumor immune responses for this deadly type of brain tumor. In Aim 1, we will study the mechanisms by which iAPC limit glioma- specific anti-tumor immune responses in vitro and in vivo. In Aim 2, we will evaluate the efficacy of combining tumor lysate-pulsed DC vaccination (to induce T-cell infiltration into tumors) with immune checkpoint inhibition and other novel immunoregulatory targets (to block iAPC function) in pre-clinical syngeneic animal models of glioblastoma, and explore the use of a novel PET tracers as non-invasive imaging biomarkers of immune response. Finally, in Aim 3, we will develop and validate predictive tumor, immunological and imaging biomarkers of response in recurrent glioblastoma patients enrolled in a Phase II clinical trial of DCVax-L +/- Nivolumab. These studies span the continuum of translational research in brain tumor immunotherapy, and will likely provided informative new insights for the development of new, rational immune-based strategies for brain tumor patients.