title: Characterization of long-circulating cationic nanoparticle formulations consisting of a two-stage PEGylation step for the delivery of siRNA in a breast cancer tumor model.
abstract: Polyethylene glycol (PEG) has been used widely in liposomal formulations as a strategy to inhibit opsonization by plasma proteins and to prolong liposome plasma circulation time. PEG can be incorporated onto the surface of liposomes either during the spontaneous self-assembling process or inserted after vesicle formation. The advantages of employing the PEG postinsertion method include improved drug encapsulation efficiency and the ability to incorporate PEG conjugates for enhanced cell binding and uptake. In this study, we propose to evaluate a cationic lipid nanoparticle formulation containing two PEGylation steps: pre- and post-siRNA insertion. Our results indicate that formulations consisting of the extra PEG post-insertion step significantly increased siRNA circulation in the plasma by two-folds in comparison with the formulations consisting of only the single PEGylation step. Moreover, this formulation was able to efficiently carry siRNA to the tumor site, increase siRNA stability and significantly downregulate luciferase mRNA expression by >50% when compared with the controls in an intraperitoneal and subcutaneous breast cancer tumor model. Overall, our cationic lipid nanoparticle formulation displayed enhanced plasma circulation, reduced liver accumulation, enhanced tumor targeting, and effective gene knockdown--demonstrating excellent utility for the delivery of siRNA.
authors.affiliation: University of Manitoba, Winnipeg, Manitoba, R3E 0T5, Canada. emmanuel_ho@umanitoba.ca
authors.forename: Emmanuel A
authors.initials: EA
authors.lastname: Ho
authors.forename: Maryam
authors.initials: M
authors.lastname: Osooly
authors.forename: Dita
authors.initials: D
authors.lastname: Strutt
authors.forename: Dana
authors.initials: D
authors.lastname: Masin
authors.forename: Youngjoo
authors.initials: Y
authors.lastname: Yang
authors.forename: Hong
authors.initials: H
authors.lastname: Yan
authors.forename: Marcel
authors.initials: M
authors.lastname: Bally
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D002412:Cations; D045744:Cell Line, Tumor; D005260:Female; D018014:Gene Transfer Techniques; D017930:Genes, Reporter; D015316:Genetic Therapy / Q000379:methods*; D008081:Liposomes; D008099:Liver / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D053758:Nanoparticles; D011092:Polyethylene Glycols / Q000737:chemistry*; D034622:RNA Interference; D020871:RNA Stability; D034741:RNA, Small Interfering / Q000097:blood / Q000737:chemistry / Q000378:metabolism* / Q000493:pharmacokinetics; D014018:Tissue Distribution; D014162:Transfection; D023041:Xenograft Model Antitumor Assays
chemical_list: D002412:Cations; D008081:Liposomes; D034741:RNA, Small Interfering; D011092:Polyethylene Glycols; D008156:Luciferases