Enhanced transfection efficiency and targeted delivery of self-assembling h-R3-dendriplexes in EGFR-overexpressing tumor cells

The efficient gene transfection, cellular uptake and targeted delivery in vivo are key issues for non-viral gene delivery vectors in cancer therapy. To solve these issues, we designed a new targeted gene delivery system based on epidermal growth factor receptor (EGFR) targeting strategy. An anti-EGFR monoclonal antibody h-R3 was introduced to dendriplexes of PAMAM and DNA via electrostatic interactions to form self-assembled h-R3-PAMAM-DNA complexes (h-R3-dendriplexes). Dendriplexes h-R3-dendriplexes represented excellent DNA encapsulation ability and formed unique nanostructures. Compared to dendriplexes, h-R3-dendriplexes presented lower cytotoxicity, higher gene transfection efficiency, excellent endosome escape ability and high nuclear accumulation in the EGFR-overexpressing HepG2 cells. Both ex vivo fluorescence imaging and confocal results of frozen section revealed that h-R3-dendriplexes showed higher targeted delivery and much better gene expression in the tumors than dendriplexes at the same N/P ratio, and h-R3-dendriplexes had accumulation primarily in the tumor and kidney. Moreover, h-R3-dendriplexes for p53 delivery indicated efficient cell growth inhibition and potentiated paclitaxel-induced cell death. These results indicate that the h-R3-dendriplexes represent a great potential to be used as efficient targeted gene delivery carriers in EGFR-overexpressing tumor cells.