title: Determination of key structure-activity relationships in siRNA delivery with a mixed micelle system.
abstract: Short interfering ribonucleic acids (siRNAs) offer a highly specific and selective form of therapy for diseases with a genetic component; however the poor pharmacokinetic properties of the molecule have impeded its development into a therapeutic for use in vivo. Several different approaches have been taken to develop a successful siRNA delivery system but these systems lack the flexibility for easy optimisation. Here, we propose a polymeric nanoparticle (PNP) system consisting of two amphiphilic diblock copolymers which allow for the rapid determination of structure-activity relationships involving gene knockdown and toxicity. The diblock copolymers self-assemble into monodisperse micelles of defined hydrodynamic diameters ranging from 30 to 100 nm dependent on the copolymer ratio. A luciferase-based high throughput assay varying PNP composition, concentration and siRNA concentration allowed the rapid identification of efficient PNP formulations for adherent and suspension cell lines. Optimised PNPs efficiently knocked down a fusion oncogene in hard to transfect human leukaemic cells raising the possibility of targeting malignant cells in a cancer-specific fashion. This approach allows the optimum PNP formulation to be identified for different cell types and conditions.
authors.affiliation: Chemical Nanoscience Laboratory, School of Chemistry, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Marta
authors.initials: M
authors.lastname: Omedes Pujol
authors.forename: Daniel J L
authors.initials: DJ
authors.lastname: Coleman
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Allen
authors.forename: Olaf
authors.initials: O
authors.lastname: Heidenreich
authors.forename: David A
authors.initials: DA
authors.lastname: Fulton
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D045744:Cell Line, Tumor; D004337:Drug Carriers / Q000737:chemistry*; D006801:Humans; D007938:Leukemia / Q000235:genetics / Q000628:therapy; D008823:Micelles; D053758:Nanoparticles / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics / Q000627:therapeutic use; D013329:Structure-Activity Relationship; D014162:Transfection
chemical_list: D001672:Biocompatible Materials; D004337:Drug Carriers; D008823:Micelles; D011108:Polymers; D034741:RNA, Small Interfering
keywords: AML; FACS; Gene knockdown; LSCM; Leukaemia; NR; Nile Red; P1; P2; PCL-b-PDMAEMA; PCL-b-PEG; PNP; Polymer micelles; Structure–activity relationships; acute myeloid leukaemia; fluorescent activated cell sorting; laser scanning confocal microscopy; polymeric nanoparticle; short interfering ribonucleic acid; siRNA