An Aptamer-Functionalized Activatable DNA Tetrahedron Nanoprobe for piRNA Imaging and Regulating in Cancer Cells.

Abstract

It has been reported that the piRNAs play critical roles in activating invasion and metastasis, evading growth suppressors and sustaining proliferative signaling of cancer and can be regarded as a novel biomarker candidate. Thus, it is necessary to develop an effective method for imaging and regulating cancer-related piRNAs to diagnose and treat cancers. Herein, we designed aptamer-functionalized activatable DNA tetrahedron nanoprobes (apt-ADTNs) to image and regulate endogenous piRNAs in cancer cells. As proof of concept, overexpressed piRNA-36026 in MCF-7 cells was used for this study. In brief, aptamer AS1411 and piRNA-36026 anti-sequence with Cy5 fluorescent dye are appended from DNA tetrahedron, then a short oligonucleotide with black hole quencher 2 (Q-oligo) is complementary with piRNA-36026 anti-sequence to quench the fluorescence of Cy5. The apt-ADTNs can recognize the MCF-7 cells through aptamer AS1411 and then enter the cells. Q-oligo is detached from the apt-ADTNs because of the binding between apt-ADTNs and piRNA-36026, leading to the recovery of Cy5 fluorescence signal. Meanwhile, the hybridization of apt-ADTNs and piRNAs-36026 results in down-regulating of dissociative piRNAs-36026 in cytoplasm and the subsequent apoptosis of MCF-7 cells. As the achievement of synchronously imaging and regulating piRNA-36026 in MCF-7 cells, we believe that this design holds great promise in application of diagnosis and therapy for cancer.