PET TUMOR AND PROLIFERATION IMAGING VIA CATIONIC AMINO ACID TRANSPORT

描述(申请人提供)：本次K08临床科学家导师研究职业发展奖申请的目的是提供额外的关键导师培训和研究经验，以实现我成为一名专注于肿瘤学分子成像的独立研究员的目标。到目前为止，在我的博士和研究跟踪放射学住院医师期间，我的培训重点是用于脑单胺转运体的PET示踪剂和用于肿瘤成像的18F标记氨基酸(AAs)的设计、合成和初步临床前评估。该计划中的培训和研究计划的完成将在肿瘤生物学、动物肿瘤模型、PET示踪剂的动力学分析以及结合使用先进的磁共振成像(MRI)和PET示踪剂的翻译和临床研究方面提供更多的关键经验。这一额外的培训将为我提供必要的关键知识和技能，使我能够独立设计和开展癌症成像领域的转化性研究项目。该方案的研究计划集中于开发通过点击反应合成的新型18F-三氮唑AA，用于阳离子AA转运、肿瘤增殖和放射治疗反应的体内PET成像。阳离子AA转运和代谢在肿瘤生物学中发挥重要作用，包括通过多胺代谢实现细胞增殖，通过一氧化氮合成实现血管生成。然而，目前还没有18F标记的化合物可用于对阳离子AA转运进行成像。为了解决肿瘤学分子成像中这一尚未满足的需求，我们将实现以下具体目标：1)合成和表征新型18F标记的1，2，3-三氮唑取代的AA类化合物，优化阳离子AA转运。2)验证前导18F-三氮唑AA作为阳离子AA转运的体内成像探针的有效性。3)在小鼠66乳腺癌模型和人在鼠(HIM)乳腺癌模型中，用18F-三氮唑AA测定体内肿瘤的增殖。4)用18F-三氮唑AA标记的放射性核素鉴别DBT脑胶质瘤小鼠的存活肿瘤和放射诱导的改变。将合成新的18F标记的三氮唑类化合物，并将在体外利用大鼠9L胶质肉瘤、小鼠DBT胶质瘤和小鼠乳腺癌66细胞系来确定它们的转运机制。将在植入这些肿瘤的啮齿动物中使用18F-三氮唑氨基酸进行生物分布和微PET研究，18F-三氮唑AA是阳离子AA运输的最佳底物。这些AAs在肿瘤中的体内摄取将与阳离子AA转运体的mRNA和蛋白质水平相关。18F-三氮唑AA在体内的摄取和动力学也将与体内肿瘤细胞增殖相关，在HIM模型中，通过小鼠66肿瘤和具有和不具有功能性P53的人乳腺肿瘤的BrDU掺入测量。将在患有颅内DBT肿瘤的小鼠身上评估18F-三氮唑AA铅区分残留的存活肿瘤和包括辐射坏死在内的治疗后影响的能力。该提案中的培训和职业发展计划包括肿瘤生物学和临床试验设计的教学课程工作。我还将在西雅图的华盛顿大学进行访问轮换，以获得更多使用[18F]Flt进行PET肿瘤增殖成像的经验，并在德国的J|Lich研究中心了解使用放射性标记氨基酸的PET-MRI的更多临床应用。我还将通过使用PET示踪剂对人体受试者进行研究，以及通过临床成像研究中心(CCIR)进行先进的核磁共振成像，积极参与多模式转换肿瘤学成像。我的导师罗伯特·H·马赫博士将提供放射性示踪剂设计、合成和肿瘤增殖成像方面的专业知识，我的联合导师基思·M·里奇博士将提供临床前和临床神经肿瘤学以及胶质瘤动物模型方面的专业知识。我还将有一个咨询委员会，该委员会每半年召开一次会议，为我的研究和职业发展活动提供指导。圣路易斯华盛顿大学的研究环境接近我的理想，拥有放射化学、基础、转化和临床肿瘤学、成像研究和临床试验方面的优秀教师和资源。我的总体目标是将这笔赠款的培训部分的经验与通过研究计划获得的数据结合起来，成功地获得独立的赠款支持，包括使用这些新的PET示踪剂进行人体研究的R01资金。我们期望这项研究能提供新的PET示踪剂，用于成像阳离子AA的转运、增殖和对放射治疗的反应，并与临床肿瘤学直接相关。接近获奖期结束时，我将向由北美放射学会赞助的临床试验方法学研讨会提交一份申请，以及一份基于通过本提案的研究部分开发的示踪剂的R21或R01赠款申请。研究和培训计划的完成将使我在获奖期结束时成为一名独立调查员。

DESCRIPTION (provided by applicant): The purpose of this K08 Mentored Clinical Scientist Research Career Development Award application is to provide additional critical mentored training and research experience to achieve my goal of becoming an independent investigator focused on molecular imaging for oncology. My training to date during my Ph.D. and research track radiology residency has focused on the design, synthesis and preliminary preclinical evaluation of PET tracers for brain monoamine transporters and 18F-labeled amino acids (AAs) for tumor imaging. Completion of the training and research plan in this proposal will provide additional key experiences in tumor biology, animal tumor models, kinetic analysis of PET tracers, and translational and clinical research using advanced magnetic resonance imaging (MRI) in conjunction with PET tracers. This additional training will provide me with the critical knowledge base and skill set needed to independently design and pursue translational research projects in cancer imaging. The research plan in this proposal focuses on developing novel 18F-triazole AAs synthesized via click the click reaction for in vivo PET imaging of cationic AA transport, tumor proliferation and response to radiation therapy. Cationic AA transport and metabolism play critical roles in tumor biology including cell proliferation through polyamine metabolism and in angiogenesis through nitric oxide synthesis. However, there are no 18F- labeled compounds available for imaging cationic AA transport. To address this unmet need in oncologic molecular imaging, we will perform the following Specific Aims: 1) Synthesize and characterize novel 18F-labeled 1,2,3-triazole substituted AAs optimized for cationic AA transport. 2) Validate the lead 18F-triazole AAs as in vivo imaging probes for cationic AA transport. 3) Measure in vivo tumor proliferation using the lead 18F-triazole AA in the mouse 66 breast cancer model and the human-in-mouse (HIM) breast cancer model. 4) Differentiate viable tumor from radiation-induced changes with the lead 18F-triazole AA in mice with intracranial DBT gliomas. Novel 18F-labeled triazole AAs will be synthesized, and their mechanisms of transport will be determined in vitro using rat 9L gliosarcoma, mouse DBT glioma and mouse mammary adenocarcinoma 66 cell lines. Biodistribution and microPET studies will be performed in rodents implanted with these tumors using the 18F- triazole AAs that are the best substrates for cationic AA transport. The in vivo uptake of these AAs in tumors will be correlated with mRNA and protein levels of cationic AA transporters. The in vivo uptake and kinetics of the lead 18F-triazole AA will also be correlated with in vivo tumor cell proliferation as measured with BrDU incorporation by mouse 66 tumors and human-derived breast tumors with and without functional p53 in the HIM model. The ability of the lead 18F-triazole AA to distinguish residual viable tumor from post-treatment effects including radiation necrosis will be assessed in mice with intracranial DBT tumors. The training and career development plan in this proposal includes didactic course work in tumor biology and clinical trial design. I will also have visiting rotations at the University of Washington in Seattle to gain additional experience with PET tumor proliferation imaging with [18F]FLT and at the J|lich Research Center in Germany to learn more about the clinical applications of PET-MRI using radiolabeled amino acids. I will also be actively involved in multimodality translational oncologic imaging through studies in human subjects with PET tracers as well as advanced MRI through the Center for Clinical Imaging Research (CCIR). My Mentor, Dr. Robert H. Mach, will provide expertise in radiotracer design, synthesis and tumor proliferation imaging, and my Co-Mentor Dr. Keith M. Rich will provide expertise in preclinical and clinical neuro-oncology and animal models of gliomas. I also will have an advisory committee who will meet semi-annually to provide guidance for my research and career development activities. The research environment at Washington University in St. Louis approaches the ideal for me, with outstanding faculty and resources in radiochemistry, basic, translational and clinical oncologic, and imaging research and clinical trials. My overall goal is to use the experience from the training component of this grant in conjunction with the data obtained through the research plan to successfully secure independent grant support including R01 funding to conduct human studies with these new PET tracers. We expect this research to provide novel PET tracers for imaging cationic AA transport, proliferation and response to radiation therapy with direct relevance to clinical oncology. Near the end of the award period, I will submit an application to the Clinical Trials Methodology Workshop sponsored by the Radiological Society of North America as well as a R21 or R01 grant application based on the tracers developed through the research component of this proposal. Completion of the research and training plan would position me to become an independent investigator at the conclusion of the award period.