Dual-isotope SPECT imaging and immunophenotyping of immune cells to determine response to immunotherapy

摘要 虽然在过去十年中，转移性黑色素瘤的免疫治疗取得了重大进展， 肾细胞癌(RCC)并不是所有患者都有反应，其他患者会随着时间的推移而产生耐药性。成百上千部小说 正在开发克服原发和获得性耐药性的治疗方案。一些组合增加了 在肿瘤中渗透细胞毒性T细胞以杀死癌细胞，而其他细胞则调节与肿瘤相关的 巨噬细胞(TAMs)在肿瘤微环境中增强T细胞活性。然而，对患者的毒性 是免疫治疗方案的一个重要限制。需要非侵入性成像技术来确定 对联合治疗的反应，使潜在的无反应者免于不必要的毒性。电流成像 技术不能同时评估T细胞和TAM水平的动态变化。整体而言 假设同时对细胞毒性T细胞和TAMs的渗透进行成像可以更好地确定 对免疫治疗方案的反应。 这项计划的目标是开发用于计算单光子发射的非侵入性成像探测器 同时对T细胞和TAM进行断层扫描(SPECT)成像，以确定联合治疗的反应。 我们预计，SPECT将准确地概括病理，并最终可能取代正在进行的治疗 可能有假性进展的患者的活组织检查。SPECT也可以补充基于组织的分析 为了通过数字空间剖面术(DSP)进一步询问肿瘤微环境，一种原位剖面术 保存空间信息的方法。数字信号处理器可以同时定量免疫细胞中的多个生物标记物 对肿瘤对联合治疗的敏感性负责。在我们的前期工作中，我们开发了工具来 利用放射性标记抗体实现体内CD8+T细胞和CD68+TAMs的示踪。我们将测试我们的 已建立的免疫系统完整的小鼠黑色素瘤和肾细胞癌肿瘤模型中的SPECT试剂。 我们将在体外鉴定它们与CD8+T细胞和CD68+TAMs的结合特性(目标1)。我们将想象 同种黑色素瘤和肾细胞癌模型体内肿瘤T细胞和的SPECT显像研究 并用数字信号处理器评估免疫治疗后小鼠和患者组织中免疫细胞的激活状态(目的 2)。这些研究将为未来双同位素SPECT在免疫治疗中的临床试验奠定基础 病人。

SUMMARY While significant progress has been made in the past decade with immunotherapy for metastatic melanoma and renal cell carcinoma (RCC), not all patients respond, and others develop resistance over time. Hundreds of novel regimens are being developed to overcome primary and acquired resistance. Some combinations increase the infiltration of cytotoxic T cells in the tumor to kill cancer cells, while others modulate tumor-associated macrophages (TAMs) to enhance the T cell activity in the tumor microenvironment. However, toxicity to patients is an important limitation to immunotherapy regimens. Non-invasive imaging techniques are needed to determine response to combination therapy to save potential non-responders from unnecessary toxicity. Current imaging techniques do not assess the dynamic changes in the levels of T cells and TAMs at the same time. The overall hypothesis is that imaging the infiltration of cytotoxic T cells and TAMs concurrently can better determine response to immunotherapy regimens. The goal of this proposal is to develop non-invasive imaging probes for single photon emission computed tomography (SPECT) imaging of T cells and TAMs concurrently to determine response to combination therapy. We anticipate that SPECT will accurately recapitulate pathology and may ultimately replace on-treatment biopsies in patients who might have pseudoprogression. SPECT may also complement tissue-based analyses to further interrogate the tumor microenvironment through digital spatial profiling (DSP), an in situ profiling method that preserves spatial information. DSP can quantify multiple biomarkers simultaneously in immune cells responsible for the tumor’s sensitivity to combination therapy. In our preliminary work we developed the tools to implement the tracking of CD8+ T cells and CD68+ TAMs in vivo with radiolabeled antibodies. We will test our SPECT agents in established murine tumor models of melanoma and RCC in mice with intact immune systems. We will characterize their binding properties to CD8+ T cells and CD68+ TAMs in vitro (Aim 1). We will image tumoral T cell and TAM infiltration in vivo by SPECT imaging in syngeneic tumor models of melanoma and RCC and assess activation status of immune cells by DSP after immunotherapy in murine and patient tissues (Aim 2). These studies will lay the foundations for future clinical trials of dual-isotope SPECT in immunotherapy-treated patients.