Liposome-coated lipoplex–based carrier for antisense oligonucleotides

Abstract

The chemical nature of genetic drugs (e.g. antisense oligonucleotides, siRNA, vectors) requires a suitable carrier system to protect them from enzymatic degradation without changing their properties and enable efficient delivery into target cells. Lipid vectors for nucleic acid delivery that have been widely investigated for years can be very effective. As the majority of attempts made in the field of cancer gene therapy have focused on solid tumors, while blood cancer cells have attracted less attention, the latter became the subject of our investigation. The lipid carrier proposed here is based on liposomes constructed by others but the lipid composition is original. A liposome-coated lipoplex (L-cL) consists of a core arising from complexation of positively charged lipid and negatively charged oligodeoxynucleotide (ODN) or plasmid DNA coated by a neutral or anionic lipid bilayer. Moreover, our lipid vector demonstrates size stability and is able to retain a high content of enclosed plasmid DNA or antisense oligodeoxynucleotides (asODNs). Observed transfection efficacies of the tested preparation using a plasmid coding for fluorescent protein were up to 60-85% of examined leukemia cells (Jurkat T and HL-60 lines) in the absence or the presence of serum. When BCL‑2 asODN was encapsulated in the L-cL, specific silencing of this gene product at both the mRNA and protein level and also a markedly decreased cell survival rate were observed in vitro. Moreover, biodistribution analysis in mice indicates prolonged circulation characteristic for PEG-modified liposomal carriers. Experiments on tumor-engrafted animals indicate substantial inhibition of tumor growth.

Keywords:

• acute leukemia
• antisense deoxynucleotides
• BCL-2 gene
• cationic lipids
• gene therapy
• liposome coated lipoplex
• lipoplex
• lipid carrier

Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed.

Acknowledgments

The authors acknowledge the expert help of Prof. J Wietrzyk and her colleagues in the animal experiments.

Funding

This work was supported in part by Wroclaw Research Center EIT+ within the project "Biotechnologies and advanced medical technologies"-Biomed (POIG.01.01.02-02-003/08) Co-financed by the European Regional Development Found (Operational Program Innovative Economy, 1.1.2). Publication costs were covered by KNOW Programme for Wrocław Biotechnology Centre.