Self-Assembled DNA Nanostructure as a Carrier for Targeted siRNA Delivery in Glioma Cells

RNA interference is a promising therapy in glioma treatment. However, the application of RNA interference has been limited in glioma therapy by RNA instability and the lack of tumor targeting. Here, we report a novel DNA tetrahedron, which can effectively deliver small interfering RNA to glioma cells and induce apoptosis.

siRNA, a small interfering RNA that can suppress the expression of survivin in glioma, was loaded into the DNA tetrahedron (TDN). To enhance the ability of active targeting of this nanoparticle, we modified one side of the DNA nanostructure with aptamer as1411 (As-TDN-R), which can selectively recognize the nucleolin in the cytomembrane of tumor cells. The modified nanoparticles were characterized by agarose gel electrophoresis, dynamic light scattering, and transmission electron microscopy. The serum stability was evaluated by agarose gel electrophoresis. Nucleolin was detected by Western blot and immunofluorescence, and targeted cellular uptake was examined by flow cytometry. The TUNEL assay, flow cytometry, and Western Blot were used to detect apoptosis in U87 cells. The gene silencing of survivin was examined by qPCR, Western Blot, and immunofluorescence.

As-TDN-R alone showed better stability towards siRNA, indicating that TDN was a good siRNA protector. Compared with TDN alone, there was increased intercellular uptake of As-TDN-R by U87 cells, evidenced by overexpressed nucleolin in glioma cell lines. TUNEL assay, flow cytometry, and Western Blot revealed increased apoptosis in the As-TDN-R group. The downregulation of survivin protein and mRNA expression levels indicated that As-TDN-R effectively silenced the target gene.

The novel nanoparticle can serve as a good carrier for targeting siRNA delivery in glioma. Further exploration of the DNA nanostructure can greatly promote the application of DNA-based drug systems in glioma.