Dicetyl Phosphate-Tetraethylenepentamine-Based Liposomes for Systemic siRNA Delivery

• Published in: Bioconjugate chemistry Vol. 22; no. 3; pp. 429 - 435
• Main Authors: Asai, Tomohiro, Matsushita, Saori, Kenjo, Eriya, Tsuzuku, Takuma, Yonenaga, Norihito, Koide, Hiroyuki, Hatanaka, Kentaro, Dewa, Takehisa, Nango, Mamoru, Maeda, Noriyuki, Kikuchi, Hiroshi, Oku, Naoto
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 16.03.2011
• Subjects: Animals; Base Sequence; Cell Line, Tumor; Cells; Chemical compounds; Cholesterol - metabolism; Cysts; Ethylenediamines - chemistry; Fibrosarcoma - metabolism; Fibrosarcoma - pathology; Gene Silencing; Humans; Injections, Intravenous; Liposomes - administration & dosage; Liposomes - chemical synthesis; Liposomes - chemistry; Liposomes - pharmacokinetics; Male; Mice; Mice, Inbred BALB C; Molecular Imaging; Organophosphates - chemistry; Polyethylene Glycols - chemistry; Protein synthesis; Ribonucleic acid; RNA; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; Rodents; Spectrophotometry, Infrared; Tumors
• ISSN: 1043-1802; 1520-4812
• DOI: 10.1021/bc1004697

Dicetyl phosphate-tetraethylenepentamine (DCP-TEPA) conjugate was newly synthesized and formed into liposomes for efficient siRNA delivery. Formulation of DCP-TEPA-based polycation liposomes (TEPA-PCL) complexed with siRNA was examined by performing knockdown experiments using stable EGFP-transfected HT1080 human fibrosarcoma cells and siRNA for GFP. An adequate amount of DCP-TEPA in TEPA-PCL and N/P ratio of TEPA-PCL/siRNA complexes were determined based on the knockdown efficiency. Then, the biodistribution of TEPA-PCL modified with poly(ethylene glycol) (PEG) was examined in BALB/c mice. As a result, TEPA-PCL modified with PEG6000 avoided reticuloendothelial system uptake and showed long circulation in the bloodstream. On the other hand, PEGylation of TEPA-PCL/siRNA complexes caused dissociation of a portion of the siRNA from the liposomes. However, we found that the use of cholesterol-conjugated siRNA improved the interaction between TEPA-PCL and siRNA, which allowed PEGylation of TEPA-PCL/siRNA complexes without siRNA dissociation. In addition, TEPA-PCL complexed with cholesterol-conjugated siRNA showed potent knockdown efficiency in stable luciferase-transfected B16−F10 murine melanoma cells. Finally, the biodistribution of cholesterol-conjugated siRNA formulated in PEGylated TEPA-PCL was examined by performing near-infrared fluorescence imaging in Colon26 NL-17 murine carcinoma-bearing mice. Our results showed that tumor targeting with siRNA via systemic administration was achieved by using PEGylated TEPA-PCL combined with active targeting with Ala-Pro-Arg-Pro-Gly, a peptide used for targeting angiogenic endothelium.