Glypican-3 (GPC3), the cellular membrane proteoglycan, has been established as a tumor biomarker for early diagnosis of hepatocellular carcinoma (HCC). GPC3 is highly expressed in more than 70% HCC tissues detected by antibody-based histopathological systems. Recently, aptamers, a short single-strand DNA or RNA generated from systematic evolution of ligands by exponential enrichment (SELEX), were reported as potential alternatives in tumor-targeted imaging and diagnosis. In this study, a total of 19 GPC3-bound aptamers were successfully screened by capillary electrophoresis (CE)-SELEX technology. After truncated, AP613-1 was confirmed to specifically target GPC3 with a dissociation constant (K_D) of 59.85 nM. When modified with a phosphorothioate linkage, APS613-1 targeted GPC3 with a K_D of 15.48 nM and could be used as a specific probe in living Huh7 and PLC/PRF/5 imaging, GPC3-positive cell lines, but not in L02 or A549, two GPC3-negative cell lines. More importantly, Alexa Fluor 750-conjugated APS613-1 could be used as a fluorescent probe to subcutaneous HCC imaging in xenograft nude mice. Our results indicated that modified AP613-1, especially APS613-1, was a potential agent in GPC3-positive tumor imaging for HCC early diagnosis.

细胞膜蛋白聚糖Glypican-3（GPC3）已被确立为早期诊断肝细胞癌（HCC）的肿瘤生物标志物。通过基于抗体的组织病理学系统检测到，GPC3在70％以上的HCC组织中高表达。最近，据报道适体是通过指数富集（SELEX）通过配体的系统进化而产生的短单链DNA或RNA，是靶向肿瘤的成像和诊断的潜在替代物。在这项研究中，通过毛细管电泳（CE）-SELEX技术成功筛选了19个GPC3结合的适体。截短后，确认AP613-1以59.85 nM的解离常数（K _D）特异性靶向GPC3 。当用硫代磷酸酯键修饰，APS613-1针对性GPC3用K _d特异性为15.48 nM，可以用作活体Huh7和PLC / PRF / 5成像的GPC3阳性细胞系的特异性探针，但不能用于两种GPC3阴性的细胞L02或A549。更重要的是，Alexa Fluor 750偶联的APS613-1可用作异种移植裸鼠皮下HCC成像的荧光探针。我们的结果表明，经修饰的AP613-1（尤其是APS613-1）是GPC3阳性肿瘤成像中HCC早期诊断的潜在药物。