PET Imaging of Cancer with pH (Low) Insertion Peptide (pHLIP)

描述（由申请人提供）： 生理过程（例如，缺氧、酸度和温度变化），它们存在于90%的肿瘤微环境中，被认为是有希望的肿瘤靶向环境标志物。我们建议采用固有的肿瘤酸度的检测肿瘤的非侵入性核成像。我们的方法是基于pHLIP（pH（低）插入肽）与细胞膜的pH选择性相互作用。pHLIP肽含有37个残基，在中性pH下，它与膜表面的相互作用较弱，但在酸性pH（<7.0）下，它插入跨膜并形成稳定的跨膜1-螺旋。与PET或SPECT放射性核素缀合的pHLIP提供了开发非侵入性成像方法的可能性，该方法将可转化为临床用于诊断实体瘤和转移。该项目的主要目标是开发一种基于pHLIP的放射性药物的实体瘤成像新方法，最终目标是将药剂转化为临床。我们计划在拟议的研究中进行四个具体目标：（1）开发用于确定最佳的基于64 Cu-pHLIP的放射性药物的缀合和标记方案，并在LnCAP和PC-3肿瘤模型中进行体外和体内比较试验;（2）确定哪种放射性金属导致pHLIP的最佳体内肿瘤递送;（3）开发用于制备pHLIP-S-S-金属螯合物的缀合方案，并且，其次，通过脂质体上的pHLIP、细胞培养和体内通过全身荧光成像来评估荧光Eu-DOTA的细胞内递送，以及（4）来自SA 1的最有希望的构建体，SA 2和SA 3将用PET成像和药代动力学研究来研究，其与通过MRS研究确定的肿瘤pHe直接相关。通过结合两个中心（URI和MSKCC）的知识和经验，我们的目标是开发一种优化的新型放射性金属- pHLIP肽构建体作为PET成像剂，其将可用于临床，用于原发性癌症和转移的早期发展阶段的诊断和治疗监测。 公共卫生相关性： 使用pH（低）插入肽（pHLIP）的癌症PET成像pHLIP肽含有37个残基，在中性pH下，它与膜表面的相互作用较弱，但在酸性pH（<7.0）下，它插入跨膜并形成稳定的跨膜1-螺旋。通过结合两个中心（URI和MSKCC）的知识和经验，我们的目标是开发一种优化的新型放射性肽-pHLIP肽构建体作为PET成像剂，其可用于临床诊断和监测原发性前列腺癌及其早期发展阶段转移的治疗。

DESCRIPTION (provided by applicant): Physiological processes (e.g., hypoxia, acidity and changes in temperature), which are present in 90% of tumor microenvironments, are considered promising environmental markers for tumor targeting. We propose to employ intrinsic tumor acidity for the detection of tumors by non-invasive nuclear imaging. Our method is based on the pH- selective interaction of pHLIP (pH (Low) Insertion Peptide) with cell membranes. The pHLIP peptide contains 37 residues and at neutral pH it interacts weakly with the surface of membranes, but at acidic pH (<7.0) it inserts across the membrane and forms a stable transmembrane 1-helix. pHLIP conjugated to a PET or SPECT radionuclide, offers the possibility of developing a non-invasive imaging method that will be translatable to the clinical for the diagnosis of solid tumors and metastasis. The major objective of this project is to develop a new approach for the imaging of solid tumors based on pHLIP- based radiopharmaceuticals, with the final goal of translating an agent to the clinic. There are four Specific Aims we plan to undertake in the proposed study (1) To develop conjugation and labeling protocols for determining the optimal 64Cu-pHLIP-based radiopharmaceutical and to perform comparative testing in vitro and in vivo in the LnCAP and PC-3 tumor models; (2) To determine which radiometal results in the optimal in vivo tumor delivery of pHLIP; (3) To develop a conjugation protocol for the preparation of pHLIP-S-S-metal-chelate, and, secondly, to evaluate the intracellular delivery of fluorescent Eu-DOTA by pHLIP on liposomes, cell culture and in vivo by whole-body fluorescent imaging, and, (4) The most promising constructs from SA1, SA2 & SA3 will be studied with PET imaging and pharmacokinetics studies with direct correlation to tumor pHe determined by MRS studies. By combining the knowledge and experience of the two centers (URI and MSKCC), we aim to develop an optimized, novel radiometal- pHLIP peptide construct as a PET imaging agent which will be translatable to the clinic for the diagnosis and monitoring of therapy of primary cancers and metastasis in their earliest stages of development. PUBLIC HEALTH RELEVANCE: PET Imaging of Cancer with pH (Low) Insertion Peptide (pHLIP) The pHLIP peptide contains 37 residues and at neutral pH it interacts weakly with the surface of membranes, but at acidic pH (<7.0) it inserts across the membrane and forms a stable transmembrane 1-helix. By combining the knowledge and experience of the two centers (URI and MSKCC), we aim to develop an optimized, novel radiometal-pHLIP peptide construct as a PET imaging agent which will be translatable to the clinic for the diagnosis and monitoring of therapy of primary prostate cancer and metastasis in their earliest stages of development.