1-palmitoyl-2-oleoylphosphatidylcholine and Carcinoma--Lewis-Lung

siRNA has been touted as a therapeutic molecule against genetic diseases, which include cancers. But several challenging issues remain in order to achieve efficient systemic siRNA delivery and a sufficient therapeutic effect for siRNA in vivo. Cationic liposome shows promise as a carrier for nucleic acids, as it can selectively bind to angiogenic tumor blood vessels. In this way, anti-angiogenic therapy via cationic liposome-mediated systemic siRNA delivery could be achieved in cancer therapy. In the present study, we proved our assumption by preparing various kinds of polyethylene glycol (PEG)-coated siRNA/cationic liposome complexes (siRNA-lipoplexes) and screening the avidity of these siRNA-lipoplexes upon angiogenic tumor blood vessels by means of a murine dorsal air sac (DAS) model. The lipoplex, having a lipid composition of DC-6-14/POPC/CHOL/DOPE/mPEG(2000)-DSPE=20/30/30/20/5 (molar ratio) and a charge ratio of cationic liposome and siRNA=3.81 (+/-), showed a higher binding index to newly formed blood vessels. Systemic injection with the lipoplex containing siRNA for the Argonaute2 gene (apoptosis-inducible siRNA) resulted in significant anti-tumor effect without severe side effects in mice with Lewis lung carcinoma. Our results indicate that the PEGylated cationic liposome-mediated systemic delivery of cytotoxic siRNA achieves anti-angiogenesis, resulting in the suppression of tumor growth.

Topics: Air Sacs; Animals; Argonaute Proteins; Carcinoma, Lewis Lung; Cations; Cell Cycle Checkpoints; Cell Proliferation; Cholesterol; Ethanolamines; Genetic Therapy; Lipids; Liposomes; Male; Mice; Myristates; Neovascularization, Pathologic; Neovascularization, Physiologic; Phosphatidylcholines; Phosphatidylethanolamines; Polyethylene Glycols; RNA Interference; RNA, Small Interfering; Time Factors; Transfection; Tumor Burden

With few exceptions, where local administration is feasible, progress towards broad clinical application of gene therapies requires the development of effective delivery systems. Here we report a novel non-viral gene delivery vector, 'micelle-like nanoparticle' (MNP) suitable for systemic application. MNP were engineered by condensing plasmid DNA with a chemical conjugate of phospholipid with polyethylenimine (PLPEI) and then coating the complexes with an envelope of lipid monolayer additionally containing polyethylene glycol-phosphatidyl ethanolamine (PEG-PE), resulting in spherical 'hard-core' nanoparticles loaded with DNA. MNP allowed for complete protection of the loaded DNA from enzymatic degradation, resistance to salt-induced aggregation, and reduced cytotoxicity. MNP also demonstrated prolonged blood circulation and low RES accumulation. Intravenous injection of MNP loaded with plasmid DNA encoding for the Green Fluorescence Protein (GFP) resulted in an effective transfection of a distal tumor. Thus, MNP provide a promising tool for systemic gene therapy.

Topics: Animals; Carcinoma, Lewis Lung; Cell Line, Tumor; Cell Survival; DNA; Gene Expression; Gene Transfer Techniques; Green Fluorescent Proteins; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Micelles; Microscopy, Electron; Microscopy, Fluorescence; Nanoparticles; NIH 3T3 Cells; Particle Size; Phosphatidylcholines; Phospholipids; Phosphorylcholine; Plasmids; Polyethyleneimine; Tissue Distribution; Transfection