Design of a Novel PEGylated Liposomal Vector for Systemic Delivery of siRNA to Solid Tumors

• Published in: Biological & pharmaceutical bulletin 2019/06/01, Vol.42(6), pp.996-1003
• Main Authors: Song, Furan, Sakurai, Naoyuki, Okamoto, Ayaka, Koide, Hiroyuki, Oku, Naoto, Dewa, Takehisa, Asai, Tomohiro
• Format: Article
• Language: English
• Subjects: Accumulation; Animals; Cell Cycle Proteins - genetics; Cell Line, Tumor; Electrostatic properties; Fluorescence; Gene Silencing; Genetic Vectors; Humans; Injection; Intravenous administration; liposomal vector; Liposomes; Liver - metabolism; Male; Mice, Inbred BALB C; Mice, Inbred C57BL; Neoplasms - genetics; Neoplasms - metabolism; PEGylation; Phosphatidylethanolamines - administration & dosage; Phosphatidylethanolamines - chemistry; Phosphatidylethanolamines - pharmacokinetics; Polo-Like Kinase 1; Polyethylene glycol; Polyethylene Glycols - administration & dosage; Polyethylene Glycols - chemistry; Polyethylene Glycols - pharmacokinetics; Protein Serine-Threonine Kinases - genetics; Proto-Oncogene Proteins - genetics; RNA, Small Interfering - administration & dosage; RNA, Small Interfering - blood; RNA, Small Interfering - chemistry; RNA, Small Interfering - pharmacokinetics; siRNA; small interfering RNA; Solid tumors; Spleen; Spleen - metabolism; systemic delivery; Tissue Distribution; tumor; Tumors
• ISSN: 0918-6158; 1347-5215
• DOI: 10.1248/bpb.b19-00032

A small interfering RNA (siRNA) delivery system using dioleylphosphate–diethylenetriamine conjugate (DOP-DETA)-based liposomes (DL) was assessed for systemic delivery of siRNA to tumors. DL carrying siRNA capable of inducing efficient gene silencing with low doses of siRNA were modified with polyethylene glycol (PEG-DL/siRNA) for systemic injection of siRNA. The biodistribution of DL and siRNA in the PEG-DL/siRNA was studied by using radiolabeled DL and fluorescence-labeled siRNA, respectively. DL in the PEG-DL/siRNA showed a high retention in the plasma, accumulation in the tumor, and low accumulation in the liver and spleen after intravenous injection. The in vivo effects of PEGylation were observed only when distearoylphosphatidylethanolamine (DSPE)-PEG but not distearoylglycerol (DSG)-PEG were used. This result suggests that the electrostatic interaction between lipid molecules on the surface of PEG-DL/siRNA was a critical determinant for the in vivo effect of PEGylation. When PEG-DL/siRNA (0.1 mg/kg siRNA) was intravenously injected into tumor-bearing mice, in vivo gene silencing was observed in subcutaneous tumors. These results indicate that PEG-DL/siRNA designed in this study is a promising formulation for systemic use of siRNA.