Evolution of a gastric carcinoma cell-specific DNA aptamer by live cell-SELEX

Aptamers have emerged as promising molecular probes for disease diagnosis and therapy. In the present study, the entire live cell-SELEX method was used to generate gastric cancer cell-specific aptamers. Human gastric carcinoma AGS cells were used as target cells for positive selections and human normal gastric epithelial GES-1 cells as the negative cells for counter selections. The selection procedure was monitored by gel electrophoresis and flow cytometric analysis. By successive in vitro evolutions and subsequent cloning and sequencing, a gastric carcinoma cell-specific DNA aptamer termed cy-apt 20 with minimal recognition to the controls was identified from the final enriched ssDNA pool. Flow cytometry binding assays revealed that cy-apt 20 had a >70% binding rate to AGS cells and