Selection of a novel CD19 aptamer for targeted delivery of doxorubicin to lymphoma cells

// Yan Hu 1, * , Xiaoou Li 1, * , Yacong An 1 , Jinhong Duan 1 and Xian-Da Yang 1 1 Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China * These authors have contributed equally to this work Correspondence to: Xian-Da Yang, email: ayangmd@gmail.com Keywords: CD19; aptamer; targeted therapy; lymphoma Received: August 18, 2017 Accepted: February 26, 2018 Published: June 01, 2018 ABSTRACT CD19 is overexpressed in most human B cell malignancies and considered an important tumor marker for diagnosis and treatment. Aptamers are oligonucleotides that may potentially serve as tumor-homing ligand for targeted cancer therapy with excellent affinity and specificity. In this study, we selected a novel CD19 aptamer (LC1) that was a 59-nucleotide single strand DNA. The aptamer could bind to recombinant CD19 protein with a K d of 85.4 nM, and had minimal cross reactivity to bovine serum albumin (BSA) or ovalbumin (OVA). Moreover, the aptamer was found capable of binding with the CD19-positive lymphoma cells (Ramos and Raji), but not the CD19-negative cell lines (Jurkat and NB4). An aptamer-doxorubicin complex (Apt-Dox) was also formulated, and selectively delivered doxorubicin to CD19-positive lymphoma cells in vitro . The results indicate that aptamer LC1 can recognize CD19-positive tumor cells and may potentially function as a CD19-targeting ligand.