The effects of doxorubicin loaded aptamer S3-linked DNA tetrahedrons on nasopharyngeal carcinoma

Our research group in the early stage identified CD109 as the target of aptamer S3 in nasopharyngeal carcinoma (NPC). This study was to use S3 to connect DNA tetrahedron (DT) and load doxorubicin (Dox) onto DT to develop a targeted delivery system, and explore whether S3-DT-Dox can achieve targeted therapy for NPC. Aptamer S3-conjugated DT was synthesized and loaded with Dox. The effects of S3-DT-Dox on NPC cells were investigated with laser confocal microscopy, flow cytometry, and MTS assays. A nude mouse tumor model was established from NPC 5-8F cells, and the in vivo anti-tumor activity of S3-DT-Dox was examined by using fluorescent probe labeling and hematoxylin–eosin staining. The synthesized S3-DT had high purity and stability. S3-DT specifically recognized 5-8F cells and NPC tissues in vitro. When the ratio of S3-DT to Dox was 1:20, S3-DT had the best Dox loading efficiency. The drug release rate reached the maximum (0.402 ± 0.029) at 48 h after S3-DT-Dox was prepared and mixed with PBS. S3-DT did not affect Dox toxicity to 5-8F cells, but reduced Dox toxicity to non-target cells. Meanwhile, S3-DT-Dox was able to specifically target the transplanted tumors and inhibit their growth in nude mice, with minor damage to normal tissues. Our study highlights the ability and safety of S3-DT-Dox to target NPC cells and inhibit the development NPC.