Combining targeted radionuclide therapy with a localized in situ vaccine to overcome immune suppression in the tumor microenvironment and augment T cell responses

项目摘要-项目3：我们正在开发一种免疫疗法(ImmRx)和 放射治疗(RT)在消除免疫多部位小鼠肿瘤方面显示出强大的协同作用 “冷”瘤，浸润性T细胞很少，对免疫检查点抑制(ICI)无反应。 几乎所有的儿童癌症和大多数成人癌症都是冷的，几乎没有突变或新的抗原。我们是 现在正在采取一种系统的方法来实现有效的免疫诱导根除大多数感冒肿瘤的目标 走向临床翻译。我们已经通过结合免疫调节药物根除了小鼠的大而冷的肿瘤(12 外照射(EBRT)加瘤内注射肿瘤特异性抗体(MAb)+IL2。这 方法诱导T细胞渗透到这些肿瘤，强大的T细胞记忆，表位扩散和保护 肿瘤再挑战。然而，在小鼠的第二个肿瘤上存在相同但未治疗的肿瘤(2°) 对侧翼抑制这种治疗的效果，防止根除原发(1°)肿瘤治疗 EBRT+IT单抗-IL2。在这种情况下，未经治疗的2°肿瘤会导致肿瘤特异性免疫无反应性 EBRT+IT单抗-IL2治疗1°肿瘤。我们将其称为伴随免疫耐受(CIT)。我们可以克服 对1°肿瘤给予ITmAb-IL2，对1°和2°肿瘤均给予EBRT。 2°肿瘤仅给予2~5GyRT即可克服CIT。然而，提供系统性EBRT以 由于EBRT的全身性免疫抑制，治疗许多转移部位是有问题的；但这可能 在没有免疫抑制的情况下，使用分子靶向放射性核素疗法(TRT)可以有效地实现。 131I-MIBG是治疗神经母细胞瘤(NBL)的常用放射治疗方法。我们的威斯康星大学P01团队领衔 使用烷基磷胆碱(APCH)类似物的新型TRT的临床前/临床试验 放射性核素对体内癌症的影响。这些药物在NBL异种移植中的摄取率是131I-MIBG的10倍，但与MIBG不同， 在NBL和几乎所有测试的肿瘤中都显示出类似的摄取。我们的主要候选TRT形式90Y-NM600具有 与131I-MIBG相比，在概念和临床上有许多优势，包括不需要进行潜在的门诊治疗 用来隔离病人。我们已经在我们的小鼠模型中证明了90Y-NM600和ImmRx的强大协同作用。 该项目扩展了正在进行的几个协作项目和核心的协作进展 本P01建议系统地开发TRT与我们的联合ImmRx的联合疗效。我们会 在感冒NBL和肉瘤的免疫活性小鼠模型中追求这种协同作用。我们在体内的目标是能够 使用TRT帮助根除在两个不同部位携带肉眼肿瘤的小鼠的所有癌症 播散性微转移。我们将在组织学上仔细分析肿瘤和免疫参数， 治疗组和对照组小鼠的细胞和分子水平，以及治愈的小鼠与表现出 进展或复发。此外，我们将在我们的测试中整合用于传递TRT的新载体。 这里开发的洞察力/治疗方案应该能够快速转化为感冒的临床癌症。

PROJECT SUMMARY - PROJECT 3: We are developing a combination of immunotherapy (ImmRx) and radiotherapy (RT) that shows potent synergy in eradicating cancer in mice with multiple sites of immunologically “cold” tumors, which have few infiltrating T cells and do not respond to immune checkpoint inhibition (ICI). Virtually all pediatric cancers and most cancers of adults are cold, with few mutations or neoantigens. We are now taking a systematic approach to enable potent immune-induced eradication of most cold tumors aimed towards clinical translation. We have eradicated large, cold tumors in mice by combining immunomodulatory (12 Gy) external beam RT (EBRT) with intratumoral (IT) injection of tumor-specific antibody (mAb) + IL2. This approach induces T-cell infiltration into these tumors, potent T-cell memory, epitope spread, and protection from tumor re-challenge. However, the presence of an identical but untreated second tumor (2°) on a mouse’s opposite flank inhibits the effect of this treatment, preventing eradication of the primary (1°) tumor treated with EBRT + IT mAb-IL2. In this setting, the untreated 2° tumor causes tumor-specific immune unresponsiveness to EBRT + IT mAb-IL2 at the 1° tumor. We refer to this as concomitant immune tolerance (CIT). We can overcome CIT and eliminate both tumors by giving IT mAb-IL2 to the 1° tumor and EBRT to both the 1° and 2° tumors. Delivering as little as 2-5 Gy RT to the 2° tumor can overcome CIT. However, the provision of systemic EBRT to treat many sites of metastases is problematic, due to systemic immune suppression from EBRT; but this can effectively be achieved without immune-suppression using molecular targeted radionuclide therapy (TRT). 131I-MIBG is a common TRT for neuroblastoma (NBL). Our University of Wisconsin P01 team has led preclinical/clinical testing of a novel TRT using alkyl-phospho-choline (APCh) analogs that selectively deliver radionuclides to cancers in vivo. These show >10-fold uptake over 131I-MIBG in NBL xenografts, but unlike MIBG, show similar uptake in NBL and virtually all tumors tested. Our lead-candidate form of TRT, 90Y-NM600 has many conceptual and clinical advantages over 131I-MIBG, including potential outpatient treatment with no need for patient isolation. We have demonstrated potent synergy with 90Y-NM600 and ImmRx in our mouse models. This project expands the ongoing collaborative progress of the several collaborative projects and cores in this P01 proposal to systematically develop the potency of combining TRT with our combination ImmRx. We will pursue this synergy in immunocompetent mouse models of cold NBL and sarcomas. Our in vivo goal is the ability to use TRT to help eradicate all cancer in mice bearing macroscopic tumors in two separate sites as well as disseminated micro-metastases. We will carefully analyze tumor and immune parameters at the histological, cellular, and molecular levels in treated and control mice and in mice that are cured vs. mice that show progression or relapse. In addition, we will integrate into our testing novel new vectors for delivering TRT. The insights/regimens developed here should enable rapid translation to cold clinical cancers.