Development of a novel histone H1-based recombinant fusion peptide for targeted non-viral gene delivery

In this study a new multifunctional recombinant gene delivery system (vector) was developed for targeted gene delivery to ZR-75-1 breast cancer cells. The vector backbone contained multiple domains including: (1) two tandem repeating units of truncated histone H1 to condense pDNA, (2) a model cell targeting peptide to target ZR-75-1 cells, (3) a pH-responsive synthetic fusogenic peptide, KALA, to destabilize endosomal membrane, and (4) a nuclear localization signal from human immunodeficiency virus to enhance translocation of pDNA toward the cell nucleus. The vectors were cloned and expressed in Escherichia coli BL21 (DE3) followed by purification with Ni-NTA affinity chromatography. They were then characterized using physicochemical and in vitro biological methods to evaluate the gene transfer efficiency and vector multifunctionality. The results demonstrated that the recombinant vector bearing all four functional domains had the highest rate of gene transfection efficiency as compared to the vectors which lacked one or more functional motifs. Beside the ability to target, the developed multifunctional vector was able to disrupt endosomal membranes, reach cell nucleus by utilizing microtubules and transfect efficiently while showing no detectable toxicity.