Aptamer-Functionalized DNA Origami for Targeted Codelivery 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 codelivery of a chemotherapeutic drug (doxorubicin, Dox) and two different antisense oligonucleotides (ASOs; B-cell lymphoma 2 (Bcl2) and P-glycoprotein (P-gp)) 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. Atomic force microscopy (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 phosphate-buffered saline (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/adriamycin (ADR) cells and escape from lysosomes for codelivery of Dox and ASOs into the cytoplasm. The quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and western blot assays testified the efficient silencing of Bcl2 and P-gp mRNA and downregulation of the corresponding protein expressions by Apt-DOA in Hela/ADR cells. Moreover, with the synergetic effect by codelivery of multi-ASOs and Dox, the anticancer assay showed that Apt-DOA could circumvent multidrug resistance and significantly enhance cancer therapy in Hela/ADR and MCF-7/ADR cells. Hence, this multifunctional origami-based codelivery nanocarrier presents a new strategy for efficient therapy of drug-resistant cancer.