Aptamer-Functionalized DNA Origami for Targeted Co-delivery of Antisense Oligonucleotides and Doxorubicin to Enhance Therapy in Drug-Resistant Cancer Cells.

Drug resistance is a major obstacle to the efficient therapy of drug-resistant cancer. To overcome this problem, we constructed a multifunctional DNA origami-based nanocarrier for co-delivery of chemotherapeutic drug (Dox) and two different antisense oligonucleotides (Bcl2 and P-gp ASOs) into drug-resistant cancer cells for enhanced therapy. To increase the targeting ability of origami, staple strands with 5'-end extended MUC1 sequences were used in the preparation of aptamer functionalized origami carrying ASOs (Apt-origami-ASO). Dox-loaded Apt-origami-ASO (Apt-Dox-origami-ASO) was prepared by electrostatic adsorption of Dox in origami. AFM images demonstrated the successful preparation of Apt-origami-ASO. In vitro studies showed that the Apt-Dox-origami-ASO (Apt-DOA) could controllably release Dox in pH 5.0 PBS buffer and release ASOs in response to glutathione. Further experiments revealed that the origami could protect ASOs against nuclease degradation in 10% FBS. Confocal imaging showed that the Apt-DOA nanocarrier could efficiently enter the Hela/ADR cells and escape from lysosomes for co-delivery of Dox and ASOs into the cytoplasm. The qRT-PCR and western blot assays testified the efficient silence of Bcl2 and P-gp mRNA and downregulation of the corresponding proteins expression by Apt-DOA in Hela/ADR cells. Moreover, with the synergetic effect by co-delivery of multi-ASOs and Dox, the anticancer assay showed Apt-DOA could circumvent multidrug resistance and significantly enhance cancer therapy in Hela/ADR and MCF-7/ADR cells. Hence, this multifunctional origami-based co-delivery nanocarrier presents a new strategy for efficient therapy of drug-resistant cancer.