Fast in vivo CLICK chemistries for PET imaging

描述（由申请人提供）：本提案的总体目标是使用快速体内点击化学来实现具有亲和力配体（如单克隆抗体）的生物医学成像。候选人Neal Devaraj在化学领域接受了广泛的培训，现在希望转向生物医学研究。他的近期目标是通过沉浸在转化研究中进一步发展技能，并在体内成像领域做出重大贡献。从长远来看，候选人希望从化学家完全过渡到独立的生物医学研究科学家。候选人建议在Ralph Weissleder博士的指导下在哈佛大学/MGH系统生物学中心实施该提案。除了研究计划，他的职业发展计划还包括补充课程、指导阅读、期刊俱乐部、

DESCRIPTION (provided by applicant): The broad goal of this proposal is to use fast in vivo click chemistries to enable biomedical imaging with affinity ligands such as monoclonal antibodies. The candidate, Neal Devaraj, has received extensive training in the field of chemistry and now wishes to transition to biomedical research. His immediate goal is to further develop skill sets through immersion in translational research and to make significant contributions to the field of in vivo imaging. Long term, the candidate wishes to make a full transition from chemist to independent biomedical research scientist. The candidate proposes to carry out the proposal at the Harvard/MGH Center for Systems Biology under the mentorship of Dr. Ralph Weissleder MD PhD. In addition to the research proposal, his career development plan includes supplemental coursework, mentored readings, journal clubs, attendance and presentation at several seminars and conferences, practical exposure to the imaging sciences, and close formal interaction with both his mentor and an advisory committee consisting of Prof. Robert Langer, Prof. Moungi Bawendi, and Prof. Marcelo Di Carli. The research plan aims to develop platform chemistries to allow site specific in vivo targeting of affinity ligands once they have homed to their target (i.e. decoupled administration of affinity ligand and imaging reporter). Though a large number of targeting ligands have been developed to date, target-reporter constructs have inherent pharmacokinetics which are undesirable for in vivo imaging. To achieve site specific coupling, the candidate proposes to work with the recently introduced tetrazine/strained dienophile cycloaddition. This extremely rapid reaction is highly selective, irreversible, and can be performed in physiological conditions. The proposal aims to build on this cutting-edge technology and to develop generic in vivo click reactions for molecular imaging with positron emission tomography (PET). The specific aims are to 1) develop and characterize a panel of fast "click" reactions for radioisotope labeling and 2) pursue in vivo click labeling for biomedical imaging. To test this method, the candidate will create dienophile affinity ligands against A33 glycoprotein, a surface persistent marker that is highly expressed in human colon cancers. Mice bearing primary and metastatic colon cancer will be injected with dienophile affinity ligands. After several days of clearance, a small, readily cleared tetrazine imaging probe will be administered. Imaging with PET will be used to quantify probe localization and the method will be optimized and compared to other methods such as direct labeling of affinity ligands and the metabolic reporter 18fluorodeoxglucose. If successful, the development of in vivo "click" chemistry for biomedical imaging will provide a nearly universal methodology for in vivo imaging of virtually any targeting affinity ligand. PUBLIC HEALTH RELEVANCE (provided by applicant): This project aims to develop improved methods for biomedical imaging. If successful this would lead to detection of disease much earlier when they are curable, improved diagnosis of diseased condition so appropriate treatment can be administered, and better tools for determining the effectiveness of new therapies.