Discovery of Cancer Imaging Probes using SUPREX

描述(由申请人提供)：放射学研究在发现、分期和跟踪癌症患者方面发挥着不可或缺的作用。虽然传统的成像方式提供了大量的解剖和形态信息，但许多病变仍然不确定，需要进行侵入性手术才能确定诊断。这项研究的主要目标是开发一种新型的高通量筛选平台，该平台利用基于H/D交换和质谱学的技术，称为SUPREX，用于发现可用作肿瘤特异性分子成像探针的小分子蛋白质配体。这些分子将在非侵入性测试中具有巨大的临床实用价值，以评估传统成像研究不确定的解剖异常，并更准确地确定靶向治疗的病变特征。这项工作的具体目标是优化新平台的吞吐量和整体效率，并将其用于原则验证研究，以率先发现潜在的肺癌分子显像剂。在拟议的工作中，我们将：(1)展示该平台筛选小分子组合文库的能力，以6个配体/分钟的速度结合蛋白质；(2)展示该平台具有高阳性产率(即假阳性和假阴性率低于10%)的能力；(3)筛选三个与亲环素A(CypA)结合的小分子组合文库，CypA是一种在非小细胞肺癌中过度表达的蛋白质；以及(4)表征(3)中确定的最紧密结合的“铅”分子的结合性质，包括：i)它们的结合亲和力，ii)它们相对于已知配体的结合位置，以及iii)它们在全细胞摄取试验中特异性地检测CypA过表达的能力。

DESCRIPTION (provided by applicant): Radiologic studies play an integral role in detecting, staging, and following patients with cancer. While conventional imaging modalities provide a tremendous amount of anatomic and morphologic information, many lesions remain indeterminate, and invasive procedures are required to establish a diagnosis. The primary goal of this investigation is to develop a novel high-throughput screening platform that exploits a H/D exchange- and mass spectrometry-based technique, termed SUPREX, for the discovery of small molecule protein-ligands that can be used as tumor specific molecular imaging probes. Such molecules would have tremendous clinical utility in non-invasive tests to evaluate anatomic abnormalities that are indeterminate by conventional imaging studies, and to more accurately characterize lesions for targeted therapy. The specific aims of this work are to optimize the throughput and overall efficiency of the new platform and to utilize it in a proof-of-principle study for the lead discovery of potential molecular imaging agents for lung cancer. In the proposed work we will: (1) demonstrate the platform's ability to screen small molecule combinatorial libraries for protein binding at a rate of 6 ligands/min; (2) demonstrate the platform's ability to have a high positive yield (i.e. false positive and false negative rates of less than 10%); (3) screen three small-molecule combinatorial libraries for binding to cyclophilin A (CypA), a protein that is over-expressed in non-small cell lung cancers; and (4) characterize the binding properties of the tightest binding "lead" molecules identified in (3) including: i) their binding affinity, ii) their binding site relative to known ligands, and iii) their ability to specifically detect the overexpression of CypA in whole cel uptake assays.