In vitro selection of DNA aptamers against renal cell carcinoma using living cell-SELEX

Renal cell carcinoma (RCC) is the most common form of kidney cancer with poor prognosis. Early diagnosis of RCC would significantly improve patient prognosis and quality of life. In this work, we developed new aptamer probes for RCC by using cell-SELEX (systematic evolution of ligands by exponential enrichment) only after 12 rounds of selection, in which a clear cell renal cell carcinoma (ccRCC) cell line 786-O was used as target cell, and embryonic kidney cell line 293T as negative control cell. The selected aptamers were subjected to flow cytometry and laser confocal fluorescence microscopy to evaluate their binding affinity and selectivity. The dissociation constant K_d values of four selected aptamers are all in the nanomolar range. Aptamer W786-1 with the best binding affinity and a K_d value of 9.4 ± 2.0nM was further optimized and its truncated sequence W786-1S showed considerable affinity to 786-O cells. The proteinase and temperature treatment experiment indicated that W786-1 could recognize the target 786-O cells through surface proteins, and remain good binding affinity and excellent selectivity under physiological conditions. Therefore, on the basis of its excellent targeting properties and functional versatility, W786-1 holds great potential to be used as a molecular probe for identifying and targeting RCC.