A Dual Macrophage Targeting Nanovector for Delivery of Oligodeoxynucleotides To Overcome Cancer-Associated Immunosuppression

To overcome cancer-associated immunosuppression, we prepared a dual-targeting vector to deliver CpG oligodeoxynucleotides (ODN) to macrophages. The dual-targeting system composed of mannosylated carboxymethyl chitosan (MCMC)/hyaluronan (HA) for macrophage targeting and protamine sulfate for ODN complexation was prepared by self-assembly. The effects of ODN delivery on immune cells was studied in J774A.1 cells. Due to the enhanced delivery efficiency, the dual-targeting delivery system exhibits a higher immune stimulatory activity compared with the monotargeting delivery system containing either MCMC or HA, resulting in a dramatically enhanced secretion of proinflammatory cytokines and a successful shift to activated macrophages (M1). Besides macrophages, the influence of the delivery system on tumor cells (MCF-7) was also investigated. In MCF-7 cells, the increased expressions of nuclear transcription factor-κB (NF-κB), PIK3R3, and phosphorylated protein kinase B (p-Akt) caused by activated NF-κB and phosphoinositide 3-kinase/Akt signalings were observed. Nevertheless, upregulated Fas as well as Fas ligand (FasL) may induce Fas/FasL-mediated apoptosis, which results in the increased expressions of caspases in tumor cells.