Generation of DNA Aptamers with Functional Activity in Mammalian Cells by Mimicking Retroviruses.

DNA aptamers are single-stranded DNA oligonucleotide sequences that bind to specific targets with high affinity. Currently, DNA aptamers can be produced only by synthesis. It is difficult for DNA aptamers to have a sustained impact on intracellular protein activity, which limits their clinical application. In this study, we developed a DNA aptamer expression system to generate DNA aptamers with functional activity in mammalian cells by mimicking retroviruses. Using this system, DNA aptamers targeting intracellular Ras (Ra1) and membrane-bound CD71 (XQ2) were successfully generated in cells. In particular, the expressed Ra1 not only specifically bound to the intracellular Ras protein but also inhibited the phosphorylation of downstream ERK1/2 and AKT. Furthermore, by inserting the DNA aptamer expression system for Ra1 into a lentivirus vector, the system can be delivered into cells and stably produce Ra1 over time, resulting in the inhibition of lung cancer cell proliferation. Therefore, our study provides a novel strategy for the intracellular generation of DNA aptamers with functional activity and opens a new avenue for the clinical application of intracellular DNA aptamers in disease treatment.