Selection and Identification of an ssDNA Aptamer for Fibroblast Activation Protein
Xiaomin Zhang,
Ge Yang,
Yi Zhao,
Xuyan Dai,
Wenjing Liu,
Feng Qu,
Yuanyu Huang
Affiliations
Xiaomin Zhang
Key Laboratory of Molecular Medicine and Biotherapy, Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, School of Life Science, Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
Ge Yang
Key Laboratory of Molecular Medicine and Biotherapy, Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, School of Life Science, Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
Yi Zhao
Key Laboratory of Molecular Medicine and Biotherapy, Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, School of Life Science, Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
Xuyan Dai
Economic College, Hunan Agricultural University, Changsha 410128, China
Wenjing Liu
Beijing Key Laboratory of Drug Resistance Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing Chest Hospital, Capital Medical University, Beijing 101125, China
Feng Qu
Key Laboratory of Molecular Medicine and Biotherapy, Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, School of Life Science, Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
Yuanyu Huang
Key Laboratory of Molecular Medicine and Biotherapy, Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, School of Life Science, Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
As a type II transmembrane serine protease, fibroblast activation protein (FAP) is specifically expressed on the surface of fibroblasts associated with a variety of epithelial-derived malignancies such as pancreatic cancer, breast cancer, and colon cancer. It participates in the processes of tumorigenesis, progression, and immunosuppression. FAP constitutes an important target for tumor treatment; however, the current studies on FAP are mainly related to structural characteristics, enzymatic properties, and biological functions, and aptamers of FAP have not been investigated. In this work, by using recombinant human FAP as the target, five candidate aptamers, which are AptFAP-A1, AptFAP-A2, AptFAP-A3, AptFAP-A4, and AptFAP-A5, were selected by capillary electrophoresis–systematic evolution of ligands by exponential enrichment (CE-SELEX), and their secondary structures were predicted to be mainly stem-loop. Moreover, the CE-laser-induced fluorescence (LIF) method was used to determine the equilibrium dissociation constant KD values between the FAP protein and candidate aptamers, and the KD value was in the low molar range. Finally, Cy5-labeled aptamers were co-incubated with human pancreatic cancer-associated fibroblasts highly expressing FAP protein, and confocal microscopy imaging showed that aptamer AptFAP-A4 had the highest affinities with the cells. The FAP aptamers screened in this study provide a promising direction for the development of rapid tumor diagnosis and targeted therapy.
