title: Potent gene silencing in vitro at physiological pH using chitosan polymers.
abstract: Among non-viral cationic polymers, biodegradable chitosan has during the last decade become an attractive carrier for small interference RNA (siRNA) delivery. Currently, degradation of macromolecules in the lysosomes is assumed to be a major barrier for effective siRNA transfection. Hence, transfection protocols are focused toward endosomal release mechanisms. In this work, we have tested 3 novel chitosan polymers and their siRNA delivery properties in vitro. To obtain efficient gene silencing of our model gene, S100A4, various transfection parameters were investigated, such as pH, nitrogen/phosphate ratio, photochemical internalization (PCI), media for complex formation, and cell lines. Our results showed that 2 linear chitosan polymers demonstrated excellent siRNA gene silencing, better than Lipofectamine 2000. The silencing effect was achieved without PCI treatment, under physiological pH, and with no observable reduction in cell viability.
authors.affiliation: Department of Tumor Biology, Institute of Cancer Research, The Norwegian Radium Hospital, Montebello, Norway.
authors.forename: Jens Andreas Lindin
authors.initials: JA
authors.lastname: Jørgensen
authors.forename: Eivind
authors.initials: E
authors.lastname: Hovig
authors.forename: Sigurd Leinæs
authors.initials: SL
authors.lastname: Bøe
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D048271:Chitosan / Q000737:chemistry* / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010316:Particle Size; D055668:Photochemical Processes; D034622:RNA Interference / Q000528:radiation effects; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection / Q000379:methods*; D014466:Ultraviolet Rays
chemical_list: D034741:RNA, Small Interfering; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins; C077591:S100A4 protein, human; D048271:Chitosan