Dicetyl phosphate-tetraethylenepentamine-based liposomes for systemic siRNA delivery.

Abstract

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.

• Authors: Tomohiro Asai, Saori Matsushita, Eriya Kenjo, Takuma Tsuzuku, Norihito Yonenaga, Hiroyuki Koide, Kentaro Hatanaka, Takehisa Dewa, Mamoru Nango, Noriyuki Maeda, Hiroshi Kikuchi, Naoto Oku
• Journal: Bioconjugate chemistry (Bioconjug Chem) Vol. 22 Issue 3 Pg. 429-35 (Mar 16 2011) ISSN: 1520-4812 [Electronic] United States
• PMID: 21361311 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Ethylenediamines
• Liposomes
• Organophosphates
• RNA, Small Interfering
• dicetylphosphate
• Polyethylene Glycols
• Cholesterol
• tetraethylenepentamine

Topics

• Animals
• Base Sequence
• Cell Line, Tumor
• Cholesterol (metabolism)
• Ethylenediamines (chemistry)
• Fibrosarcoma (metabolism, pathology)
• Gene Silencing
• Humans
• Injections, Intravenous
• Liposomes (administration & dosage, chemical synthesis, chemistry, pharmacokinetics)
• Male
• Mice
• Mice, Inbred BALB C
• Molecular Imaging
• Organophosphates (chemistry)
• Polyethylene Glycols (chemistry)
• RNA, Small Interfering (genetics, metabolism)
• Spectrophotometry, Infrared