CLINICAL TRANSLATION OF 19F MRI TO VISUALIZE CANCER IMMUNOTHERAPEUTIC CELLS

描述(由申请人提供)：我们建议翻译一种新的细胞磁共振技术，以可视化细胞治疗药物对抗结直肠癌(CRC)的运输。结直肠癌每年约有15万例新病例，其中6000例每年在匹兹堡大学癌症研究所(UPCI)接受治疗。有可切除肝转移的结直肠癌患者是一组独特的患者，他们总体预后较差，5年总存活率在20%-35%之间，尽管只存在微小的残留病。免疫治疗干预在这一患者群体中可能是有效的。目前，用于治疗结直肠癌和其他类型癌症的一种主要类型的细胞治疗方法是使用树突状细胞(DC)作为活疫苗，将肿瘤特异性抗原传递到淋巴结，从而在患者体内诱导内源性杀伤T细胞(即细胞毒性T细胞或CTL)。到目前为止，治疗性细胞转移后无法在体内看到细胞是癌症免疫治疗发展的最大瓶颈之一。目前基于DC的疫苗临床结果差异很大的一个常见原因是DC向淋巴结的递送不够理想。最近，阿伦斯博士的实验室展示了一项引人注目的技术，可以通过核磁共振显示移植细胞。在这种方法中，细胞体外标记一种新型的全氟聚醚(PFPE)纳米颗粒组合物，然后引入患者体内。随后，使用19F磁共振成像在体内监测细胞迁移。这种方法的主要优点是，19F图像对标记的细胞具有极高的选择性，没有来自宿主组织的背景信号。此外，在感兴趣的区域进行准确的细胞量化是可能的。数据显示，PFPE纳米颗粒在细胞内具有高度的生物相容性。到目前为止，已经在啮齿动物模型上进行了几项活体成像研究。CELSENSE公司最近研制和制造了一种临床级别的启用PFPE纳米颗粒试剂。CELSENSE公司目前正在对这种试剂进行强制性的体外和动物安全性研究，以供最终的人类使用。拟议的研究将使我们能够同时推进人体细胞治疗的活体跟踪技术，同时为正在进行的结直肠癌免疫治疗临床研究提供见解，该研究由UPCI的Kalinski和Bartlett博士指导。拟议的项目有三个具体目标：(1)建立治疗细胞的全氟乙烷标记方案。我们将为免疫治疗树突状细胞的PFPE标记制定最佳的组织培养方案。(1B)用PFPE标记后测定治疗细胞的体外特性。我们将严格评估PFPE标记在体外诱导DC功能和表型改变的程度。(2a，b)在啮齿动物模型中研究标记DC的细胞转运和PFPE清除。(3A)在3T临床磁共振成像系统上实现灵敏的~(19)F-MRI/MRS方法。我们将优化脉冲序列，并使用模体研究评估最小可检测细胞数量。(3B)对结直肠癌患者的免疫治疗细胞进行跟踪的初步研究。我们将修改现有的UPCICRC治疗方案(UPCI05-063；BB-IND 13,234)，以包括对转移细胞的成像。在一小群结直肠癌患者(n=6)中，我们将想象基于DC的疫苗转移到淋巴结的情况。我们将遵循传统的皮内给药途径和一种新的淋巴内给药途径，以加速DC向淋巴结的输送，并保护增强剂量的DC不被先前诱导的CTL消除。这项拟议的翻译研究是评估基于19F MRI/MRS的细胞跟踪在临床上应用的潜力的第一次努力。此外，我们将获得对改进转移性结直肠癌和其他形式癌症的免疫治疗策略至关重要的初步数据。匹兹堡地区在癌症免疫治疗和成像创新方面拥有非凡的实力。我们从该地区组织了一支强有力的研究团队来实施这一项目。公共卫生相关性：在这项提案中，我们将使用先进的磁共振成像(MRI)技术来可视化细胞免疫疗法对抗结直肠癌的传播。细胞免疫疗法最常应用于晚期癌症，现有的治疗方法疗效有限，细胞免疫疗法是对特定细胞的管理，这些细胞可以杀死癌细胞或产生对疾病的免疫力。免疫疗法被定位为补充手术、化疗和放射治疗的第四种癌症治疗策略。目前，接种后看不到体内的细胞是癌症免疫治疗发展的最大瓶颈之一。该提案将采用现代成像工具来解决这一紧迫需求，同时为正在进行的结直肠癌免疫治疗临床研究提供见解。

DESCRIPTION (provided by applicant): We propose to translate a novel cellular MRI technology to visualize the trafficking of cellular therapeutics against colorectal cancer (CRC). CRC accounts for approximately 150,000 new cases annually, and 6,000 of these are treated every year at the University of Pittsburgh Cancer Institute (UPCI). CRC patients with resectable liver metastases constitute a group of patients with a unique combination of an overall poor prognosis and a 5-year overall survival rate between 20-35%, despite the presence of only minimal residual disease. Immunotherapeutic interventions may potentially be effective in this patient population. Currently, a major type of cell-based therapy used for CRC and other cancer types uses dendritic cells (DCs) as live vaccines that deliver tumor-specific antigens to the lymph nodes thereby inducing endogenous killer T cells (i.e., cytotoxic T cells or CTLs) in patients. To date, the inability to see the cells in vivo following therapeutic cell transfer is one of the greatest bottlenecks in the development of cancer immunotherapy. A commonly cited reason for the highly varied clinical outcomes of current DC-based vaccines is sub-optimal DC delivery to the lymph nodes. Recently, the laboratory of Dr. Ahrens has demonstrated a compelling technology that makes transplanted cells visible via MRI. In this approach, cells are labeled ex vivo with a novel perfluoropolyether (PFPE) nanoparticle composition and then introduced into the patient. Cell migration is subsequently monitored in vivo using 19F MRI. The key advantage of this approach is that the 19F images are extremely selective for the labeled cells, with no background signal from the host's tissues. Furthermore, accurate cell quantification in regions of interest is possible. Data show that PFPE nanoparticles are highly biocompatible inside cells. To date, several in vivo imaging studies have been conducted in rodent models. A clinical-grade version of the enabling PFPE nanoparticle reagent has recently been formulated and manufactured by Celsense, Inc. Celsense is currently performing mandatory in vitro and animal safety studies of this reagent for eventual human use. The proposed studies will allow us to simultaneously advance the technology of in vivo tracking of cell therapy in humans, while giving insights into ongoing clinical studies of immunotherapy in CRC, directed by Drs. Kalinski and Bartlett at the UPCI. The proposed project has three Specific Aims: (1a) Establish PFPE labeling protocols for therapeutic cells. We will develop optimal tissue culture protocols for PFPE labeling of immunotherapeutic DCs. (1b) Determine in vitro characteristics of therapeutic cells following labeling with PFPE. We will rigorously evaluate the degree to which PFPE labeling induces any alterations in DC function and phenotype in vitro. (2a,b) study cell trafficking and PFPE clearance of labeled DCs in a rodent model. (3a) Implementation of sensitive 19F MRI/MRS methods on a 3T clinical MRI system. We will optimize pulse sequences and evaluate the minimum detectable cell numbers using phantom studies. (3b) Pilot study tracking immunotherapeutic cells in CRC patients. We will amend the existing UPCI CRC therapeutic protocol (UPCI 05-063; BB-IND 13,234) to include imaging of transferred cells. In a small cohort of CRC patients (n=6), we will image the migration of DC-based vaccines to the lymph nodes. We will follow their administration by the traditional intradermal route and a novel intralymphatic route developed to accelerate the DC delivery to the lymph nodes and to protect booster doses of DCs from elimination by the previously-induced CTLs. The proposed translational studies are the first effort to evaluate the potential of 19F MRI/MRS-based cell tracking for clinical use. Additionally, we will garner preliminary data critically important for improving the immunotherapeutic strategies in metastatic CRC and other forms of cancer. The Pittsburgh region has exceptional strength in cancer immunotherapy and imaging innovations. We have organized a potent research team from the region to conduct this project. PUBLIC HEALTH RELEVANCE: In this proposal we will use advanced magnetic resonance imaging (MRI) technology to visualize the trafficking of cellular immunotherapy against colorectal cancer. Most often applied to advanced cancer, where existing therapies have limited efficacy, cellular immunotherapy is the administration of specialized cells that kill cancer cells or produce immunity to the disease. Immunotherapy is positioned to become a fourth strategy in cancer treatment supplementing surgery, chemotherapy, and radiation. Currently, the inability to see cells in the body following inoculation is one of the greatest bottlenecks in the development of cancer immunotherapy. This proposal will adapt modern imaging tools to address this urgent need, while giving insights into ongoing clinical studies of immunotherapy in colorectal cancer.