A Polyethylenimine-Containing and Transferrin-Conjugated Lipid Nanoparticle System for Antisense Oligonucleotide Delivery to AML

Limited success of antisense oligonucleotides (ASO) in clinical anticancer therapy calls for more effective delivery carriers. The goal of this study was to develop a nanoparticle system for delivery of ASO G3139, which targets mRNA of antiapoptotic protein Bcl-2, to acute myeloid leukemia (AML) cells. The synthesized nanoparticle Tf-LPN-G3139 contained a small molecular weight polyethylenimine and two cationic lipids as condensing agents, with transferrin on its surface for selective binding and enhanced cellular uptake. The optimized nitrogen to phosphate (N/P) ratio was 4 to achieve small particle size and high G3139 entrapment efficiency. The Tf-LPN-G3139 exhibited excellent colloidal stability during storage for at least 12 weeks and remained intact for 4 hours in nuclease-containing serum. The cellular uptake results showed extensive internalization of fluorescence-labelled G3139 in MV4-11 cells through Tf-LPN. Following transfection, Tf-LPN-G3139 at 1 µM ASO level induced 54% Bcl-2 downregulation and >20-fold apoptosis compared to no treatment. When evaluated in mice bearing human xenograft AML tumors, Tf-LPN-G3139 suppressed tumor growth by ~60% at the end of treatment period, accompanied by remarkable pharmacological effect of Bcl-2 inhibition in tumor. In conclusion, Tf-LPN-G3139 is a promising nanoparticle system for ASO G3139 delivery to AML and warrants further investigations.