Imaging a functional tumorigenic biomarker in the transformed epithelium
Imaging a functional tumorigenic biomarker in the transformed epithelium
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DOI：
10.1073/pnas.1218694110
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发表时间：
2013-01-02
影响因子：
11.1
通讯作者：
Craik, Charles S.
中科院分区：
文献类型：
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作者：
LeBeau, Aaron M.;Lee, Minhee;Craik, Charles S.
负责与癌症相关的瘤周蛋白水解增加的蛋白酶代表了监测肿瘤发生的功能性生物标志物。一种有吸引力的细胞外生物标志物是跨膜丝氨酸蛋白酶基质酶。 matriptase 存在于上皮细胞表面，其活性受其同源抑制剂肝细胞生长因子激活剂抑制剂-1 (HAI-1) 调节。定量质谱分析使我们能够证明，在选定的癌症中，HAI-1 表达降低，从而导致激活的 matriptase。开发了一种专门用于测量新出现的活性基质酶的临床前探针。使用针对 matriptase 的活性位点特异性重组人抗体，我们发现活性 matriptase 的选择性靶向可用于可视化致瘤上皮。活细胞荧光成像通过显示探针仅定位于表面具有活性基质酶的癌细胞系来验证抗体的体外选择性。该抗体的免疫荧光记录了组织微阵列中 68% 的原发性和转移性结肠癌切片中活性 matriptase 的显着水平。使用近红外和单光子发射计算机断层扫描成像在人结肠癌异种移植物和患者来源的异种移植物模型中测量体内活性形式的 matriptase 的标记。活性基质酶对放射性标记抗体 In-111-A11 的肿瘤摄取在异种移植物中很高（每克注射剂量 28%），并且通过添加基质酶特异性的大肠杆菌素变体在体内被阻断。这些发现表明，通过 HAI-1 依赖性机制，新兴的活性 matriptase 是转化上皮的功能性生物标志物，并且其蛋白水解活性可用于非侵入性评估体内肿瘤发生。
Proteases responsible for the increased peritumoral proteolysis associated with cancer represent functional biomarkers for monitoring tumorigenesis. One attractive extracellular biomarker is the transmembrane serine protease matriptase. Found on the surface of epithelial cells, the activity of matriptase is regulated by its cognate inhibitor hepatocyte growth factor activator inhibitor-1 (HAI-1). Quantitative mass spectrometry allowed us to show that, in selected cancers, HAI-1 expression decreases, leading to active matriptase. A preclinical probe specific for the measurement of emergent active matriptase was developed. Using an active-site-specific, recombinant human antibody for matriptase, we found that the selective targeting of active matriptase can be used to visualize the tumorigenic epithelium. Live-cell fluorescence imaging validated the selectivity of the antibody in vitro by showing that the probe localized only to cancer cell lines with active matriptase on the surface. Immunofluorescence with the antibody documented significant levels of active matriptase in 68% of primary and metastatic colon cancer sections from tissue microarrays. Labeling of the active form of matriptase in vivo was measured in human colon cancer xenografts and in a patient-derived xenograft model using near-infrared and single-photon emission computed tomography imaging. Tumor uptake of the radiolabeled antibody, In-111-A11, by active matriptase was high in xenografts (28% injected dose per gram) and was blocked in vivo by the addition of a matriptase-specific variant of ecotin. These findings suggest, through a HAI-1-dependent mechanism, that emergent active matriptase is a functional biomarker of the transformed epithelium and that its proteolytic activity can be exploited to noninvasively evaluate tumorigenesis in vivo.