Phosphorothioate-Modified AP613-1 Specifically Targets GPC3 when Used for Hepatocellular Carcinoma Cell Imaging

• Main Authors: Lili Dong, Hongxin Zhou, Menglong Zhao, Xinghui Gao, Yang Liu, Dongli Liu, Wei Guo, Hongwei Hu, Qian Xie, Jia Fan, Jiang Lin, Weizhong Wu
• Format: Article
• Language: English
• Published: Elsevier 2018-12-01
• Series: Molecular Therapy: Nucleic Acids
• Online Access: http://www.sciencedirect.com/science/article/pii/S2162253118302579

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 (KD) of 59.85 nM. When modified with a phosphorothioate linkage, APS613-1 targeted GPC3 with a KD 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. Keywords: GPC3, CE-SELEX, ssDNA aptamer, flow cytometry, cell imaging