Drug Design, Development and Therapy (Sep 2021)
Selection of DNA Aptamers Recognizing EpCAM-Positive Prostate Cancer by Cell-SELEX for in vitro and in vivo MR Imaging
Abstract
Jinman Zhong,1,* Jianke Ding,2,* Lei Deng,1 Ying Xiang,1 Duoduo Liu,1 Yanyan Zhang,1 Xin Chen,1 Quanxin Yang1 1Department of Radiology, The Second Affiliated Hospital, Xi’ an Jiaotong University, Xi’an, Shaanxi Province, 710004, People’s Republic of China; 2Department of Plastic and Reconstructive Surgery, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi Province, 710032, People’s Republic of China*These authors contributed equally to this workCorrespondence: Quanxin Yang; Xin ChenDepartment of Radiology, The Second Affiliated Hospital, Xi’ an Jiaotong University, 157 Xiwu Road, Xi’an, Shaanxi Province, 710004, People’s Republic of ChinaEmail [email protected]; [email protected]: The sensitive and specific detection of pathogenic cells is important in tumor diagnosis at an early stage. Aptamers are short single-stranded oligonucleotides evolved from systematic evolution of ligands by exponential enrichment (SELEX). It has been proved that aptamers can interact with cognate target molecules with high affinity and specificity and have great potential in the development of medical imaging at molecular level.Purpose: To select epithelial cell adhesion molecule (EpCAM) specific aptamers targeting prostate cancer and further to conjugate aptamers with GoldMag nanoparticles (a typical iron oxide core/gold shell structure) to construct magnetic molecular probes for medical imaging.Methods: EpCAM-specific aptamers were selected by Cell-SELEX. The enrichment of specific aptamer candidates was monitored by flow cytometric analysis. Aptamers were further conjugated with GoldMag nanoparticles to construct magnetic molecular probes. The affinity and specificity of aptamer candidates and aptamer-conjugated GoldMag nanoparticles were evaluated. The MR imaging of aptamer-conjugated GoldMag nanoparticles to prostate cancer was further explored in vitro and in vivo.Results: After 12 rounds of selection, aptamer candidates Eppc6 and Eppc14 could specifically target three types of prostate cancer cells, revealing a high affinity of Eppc6 and Eppc14. Moreover, aptamer-conjugated GoldMag nanoparticles not only exhibited good affinity to different prostate cancer cells but also produced strong T2WI signal intensity reduction distinguished from peritumoral tissue in MRI, indicating that the molecular probes possess both the affinity properties of EpCAM-specific aptamer and the superparamagnetic features of iron oxide.Conclusion: Our study indicates that aptamer Eppc6 and Eppc14 can recognize prostate cancer cells and tissues. The aptamer-conjugated GoldMag nanoparticles constructed in the study can be used as a molecular imaging agent for detection of PCa in MRI.Keywords: EpCAM, aptamer, Cell-SELEX, prostate cancer
