title: Dicer-labile PEG conjugates for siRNA delivery.
abstract: Poly(ethylene glycol) (PEG) conjugates of Dicer-substrate small interfering RNA (DsiRNA) have been prepared to investigate a new siRNA release strategy. 3'-sense or 5'-antisense thiol-modified, blunt-ended DsiRNAs, inhibiting enhanced green fluorescent protein (eGFP) expression, were covalently conjugated to PEG with varying molecular weights (2, 10, and 20 kg/mol) through a stable thioether bond using a Michael addition reaction. The DsiRNA conjugates with 2 kg/mol PEG (both 3'-sense or 5'-antisense strand conjugated) and the 10 kg/mol PEG conjugated to the 3'-sense strand of DsiRNA were efficiently cleaved by recombinant human Dicer to 21-mer siRNA, as determined by gel electrophoresis. Importantly, 2 and 10 kg/mol PEG conjugated to the 3'-sense strand of DsiRNA showed potent gene silencing activity in human neuroblastoma (SH-EP) cells, stably expressing eGFP, at both the mRNA and protein levels. Moreover, the 10 kg/mol PEG conjugates of the 3'-sense strand of DsiRNA were less immunogenic when compared with the unmodified DsiRNA, determined via an immune stimulation assay on human peripheral blood mononuclear cells.
authors: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.
authors: Siew Ching
authors: SC
authors: Kow
authors: Josh
authors: J
authors: McCarroll
authors: David
authors: D
authors: Valade
authors: Cyrille
authors: C
authors: Boyer
authors: Tanya
authors: T
authors: Dwarte
authors: Thomas P
authors: TP
authors: Davis
authors: Maria
authors: M
authors: Kavallaris
authors: Volga
authors: V
authors: Bulmus
mesh_terms: D045744:Cell Line, Tumor; D053487:DEAD-box RNA Helicases / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008970:Molecular Weight; D009447:Neuroblastoma / Q000235:genetics; D011092:Polyethylene Glycols / Q000737:chemistry*; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000235:genetics; D034741:RNA, Small Interfering / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D043244:Ribonuclease III / Q000378:metabolism; D014162:Transfection / Q000379:methods*
chemical_list: D012330:RNA, Double-Stranded; D034741:RNA, Small Interfering; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D011092:Polyethylene Glycols; C408087:DICER1 protein, human; D043244:Ribonuclease III; D053487:DEAD-box RNA Helicases