Discovery of Cancer Imaging Probes using SUPREX

描述（由申请人提供）：放射学研究在癌症患者的检测、分期和随访中起着不可或缺的作用。虽然传统的成像方式提供了大量的解剖和形态学信息，许多病变仍然是不确定的，需要侵入性的程序来建立诊断。本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H/D交换和质谱技术，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。这样的分子将在非侵入性测试中具有巨大的临床实用性，以评估常规成像研究无法确定的解剖异常，并更准确地表征靶向治疗的病变。这项工作的具体目标是优化新平台的吞吐量和整体效率，并将其用于原理验证研究，以发现潜在的肺癌分子成像剂。在拟议的工作中，我们将：（1）证明该平台能够以6个配体/min的速率筛选小分子组合文库的蛋白质结合;（2）证明该平台具有高阳性产率的能力（即假阳性和假阴性率低于10%）;（3）筛选三个小分子组合文库以结合亲环素A（CypA），一种在非小细胞肺癌中过表达的蛋白质;和（4）表征（3）中鉴定的最紧密结合“先导”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点，和iii）它们在全细胞摄取测定中特异性检测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.