PET Imaging of Tumor Targeting & Role of T Lymphocytes

描述(由申请人提供)： 这项建议的总体目标是开发重复的非侵入性体内成像方法，用于在体内对T淋巴细胞过继转移抗肿瘤疫苗后的命运进行成像。所提出的成像方法将允许回答与T细胞迁移和归巢到肿瘤靶点、它们随后的激活和细胞溶解活性以及T细胞存活的持续时间相关的几个问题。所提出的成像方法的最终目的是评估肿瘤靶点T细胞的激活程度，评估肿瘤浸润性T细胞的细胞学潜力，并预测其在治疗早期的肿瘤溶解效果。我们建议将T细胞的遗传标记与多个报告基因相结合，然后重复给药短寿命的放射性同位素报告探针，以使用PET或其他成像技术(即荧光、生物发光、MRI)顺序成像报告基因表达的细胞。具体地说，我们将探索用新的报告基因-报告探针组合和新的多报告基因构建对T细胞进行遗传标记的可行性。我们将使用[124I]FIAU和新开发的用于hTK2[2‘-18F]FeAU和[11C]Feau成像的新开发的短寿命放射性标记探针来测试新的报告基因-截短型人线粒体胸苷激酶2(HTK2)的可行性。我们计划开发几个双报告系统，其中hTK2将结构性地表达为“灯塔”报告基因，突变的HSV1-tk(HSV1-sr39tk)基因(由[18F]FHBG成像)将以T细胞和激活特异性的方式表达为“传感器”报告基因。建议的多报告基因成像范例将用于评估和优化基于人工抗CEA或抗PSMA T细胞受体的新型抗癌T细胞疫苗，分别用于治疗结直肠癌和前列腺癌。成像将用于监测过继转移的T细胞在与各种细胞因子共刺激治疗之前和期间的运输、定位和激活情况。这些研究将评估拟议的治疗和成像方法在临床环境中实施的可行性和适用性。

DESCRIPTION (provided by applicant): The overall aim of this proposal is to develop approaches for repetitive non-invasive in vivo imaging of the fate of T lymphocytes after their adoptive transfer for anti-tumor vaccination. The proposed imaging approaches will allow to answer several questions related to T-cell migration and homing to the tumor target, their subsequent activation and cytolytic activity, and the duration of T-cell viability. The ultimate aim of the proposed imaging approaches is to assess the degree of T cell activation at tumor target, to assess the cytolitic potential of tumor infiltrating T cells, and to predict their tumorolytic efficacy early on during therapy. We propose to combine the genetic labeling of T-cells with multiple reporter genes followed by the repetitive administration of short-lived radioisotope reporter probes to sequentially image the reporter gene expressing cells with PET or other imaging technologies (i.e., fluorescence, bioluminescence, MRI). Specifically, we will explore the feasibility of genetic labeling of T-cells with novel reporter gene - reporter probe combinations and novel multi-reporter gene constructs. We will test the feasibity of a novel reporter gene, the truncated human mitochondrial thymidine kinase type two (hTK2) using [124I]FIAU and newly developed short lived radiolabeled probes for imaging of hTK2 [2'-18F]FEAU and [11C]FEAU. We plan to develop several dual-reporter systems in which the hTK2 will be expressed constitutively as a "beacon" reporter gene and the mutant HSV1-tk (HSV1-sr39tk) gene (imaged by [18F]FHBG) will be expressed as "sensor" reporter gene in a T cell- and activation-specific manner. The proposed multi-reporter gene imaging paradigm will be implemented in the assessment and optimization of new anti-cancer T-cell vaccines that are based on the artificial anti-CEA or anti-PSMA T-cell receptors and used for treatment of colorectal and prostate carcinomas, respectively. Imaging will be used for monitoring the trafficking, localization and activation of adoptively transferred T cells before and during co-stimulatory therapy with various cytokines. These studies will assess the feasibility and applicability of the proposed therapeutic and imaging approaches for implementation in clinical setting.