PET TUMOR AND PROLIFERATION IMAGING VIA CATIONIC AMINO ACID TRANSPORT

描述（由申请人提供）：本次K08指导临床科学家研究职业发展奖申请的目的是提供额外的重要指导培训和研究经验，以实现我成为一名专注于肿瘤分子成像的独立研究者的目标。到目前为止，在我的博士学位和研究轨道放射学实习期间，我的培训主要集中在脑单胺转运蛋白和18f标记氨基酸（AAs）的PET示踪剂的设计、合成和初步临床前评估。完成本提案中的培训和研究计划将为肿瘤生物学，动物肿瘤模型，PET示踪剂动力学分析以及结合PET示踪剂的先进磁共振成像（MRI）的转化和临床研究提供额外的关键经验。这种额外的培训将为我提供独立设计和从事癌症成像转化研究项目所需的关键知识基础和技能。本课题的研究计划重点是通过click - click反应合成新型18f -三唑原子，用于阳离子AA转运、肿瘤增殖和放射治疗应答的体内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，包括通过多胺代谢促进细胞增殖和通过一氧化氮合成血管生成。然而，没有18F标记的化合物可用于成像阳离子AA运输。为了解决肿瘤分子成像中这一未满足的需求，我们将实现以下具体目标：1)合成并表征新型18f标记的1,2,3-三唑取代的阳离子AA转运优化的AA。2)验证铅18f -三唑原子吸收剂作为阳离子AA转运的体内成像探针。3)用18f -三唑AA铅在小鼠66乳腺癌模型和人鼠（HIM）乳腺癌模型中测定体内肿瘤增殖。4)应用18f -三唑AA铅对脑内DBT胶质瘤小鼠活体肿瘤和辐射诱导的改变进行鉴别。利用大鼠9L胶质瘤、小鼠DBT胶质瘤和小鼠乳腺腺癌66细胞系，合成新型18f标记的三唑类AAs，并在体外研究其转运机制。生物分布和微pet研究将在植入这些肿瘤的啮齿动物中进行，使用18F-三唑AAs作为阳离子AA运输的最佳底物。这些AA在肿瘤中的体内摄取将与阳离子AA转运体的mRNA和蛋白水平相关。在he模型中，通过BrDU掺入小鼠66个肿瘤和人源性乳腺肿瘤（含或不含功能性p53）测量，铅18f -三唑AA的体内摄取和动力学也将与体内肿瘤细胞增殖相关。18f -三唑AA铅区分残余活肿瘤和治疗后影响（包括放射坏死）的能力将在颅内DBT肿瘤小鼠中进行评估。本提案中的培训和职业发展计划包括肿瘤生物学的教学课程和临床试验设计。我还将在西雅图的华盛顿大学进行访问轮换，以获得使用[18F]FLT进行PET肿瘤增殖成像的额外经验，并在德国的J|lich研究中心进行访问轮换，以更多地了解使用放射性标记氨基酸进行PET- mri的临床应用。我还将积极参与通过PET示踪剂对人类受试者进行的多模态转化肿瘤成像研究以及通过临床成像研究中心（CCIR）进行的高级MRI研究。我的导师Robert H. Mach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，而我的联合导师Keith M. Rich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，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（Washington University in St. Louis）的研究环境非常适合我，它在放射化学、基础、转化和临床肿瘤学、成像研究和临床试验方面拥有优秀的师资和资源。我的总体目标是利用这项拨款的培训部分的经验，结合通过研究计划获得的数据，成功地获得独立的拨款支持，包括R01资金，用这些新的PET示踪剂进行人体研究。我们期望这项研究能够提供新的PET示踪剂，用于成像阳离子AA的运输、增殖和对放射治疗的反应，与临床肿瘤学直接相关。在奖励期结束时，我将向北美放射学会赞助的临床试验方法学研讨会提交申请，并根据本提案的研究部分开发的示踪剂提交R21或R01资助申请。研究和培训计划的完成将使我在奖励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.