Pyridylthiourea-grafted polyethylenimine offers an effective assistance to siRNA-mediated gene silencing in vitro and in vivo

• Published in: Journal of controlled release Vol. 157; no. 3; pp. 418 - 426
• Main Authors: Creusat, Gaelle, Thomann, Jean-Sébastien, Maglott, Anne, Pons, Bénédicte, Dontenwill, Monique, Guérin, Eric, Frisch, Benoit, Zuber, Guy
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 10.02.2012; Elsevier
• Subjects: Acidity; Animals; Biological and medical sciences; Cell Line, Tumor; Cell Survival - drug effects; Controlled release; Erythrocytes - drug effects; Erythrocytes - pathology; Gene Silencing; General pharmacology; Glioblastoma; Glucose; hemolysis; Hemolysis - drug effects; Humans; Hydrophobic and Hydrophilic Interactions; in vivo studies; luciferase; Male; Medical sciences; Mice; Mice, Nude; Nanovector; Neoplasm Transplantation; neoplasms; Neoplasms - metabolism; nucleic acids; pH effects; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Polyethyleneimine - administration & dosage; Polyethyleneimine - chemistry; Polymer; polymers; RNA, Small Interfering - administration & dosage; RNA, Small Interfering - chemistry; Sheep; siRNA; siRNA delivery; small interfering RNA; synthesis; therapeutics; Thiourea - administration & dosage; Thiourea - analogs & derivatives; Thiourea - chemistry; Transfection; Tumors; siRNA delivery; Polymer; Nanovector; Transfection; In vivo; Gene silencing; RNA interference; Pharmaceutical technology; siRNA; Ethyleneimine copolymer; In vitro; Genetic transfer
• ISSN: 0168-3659; 1873-4995
• DOI: 10.1016/j.jconrel.2011.10.007

Success of synthetic interfering nucleic acids (siRNAs)-based therapy relies almost exclusively on effective, safe and preferably nanometric delivery systems which can be easily prepared, even at high concentrations. We prepared by chemical synthesis various self-assembling polymers to entrap siRNAs into stable polyplexes outside cells but with a disassembly potential upon sensing endosomal acidity. Our results revealed that pyridylthiourea-grafted polyethylenimine (πPΕΙ) followed the above-mentioned principles. It led to above 90% siRNA-mediated gene silencing in vitro on U87 cells at 10nM siRNA concentration and did not have a hemolytic activity. Assembly of siRNA/πPΕΙ at high concentration was then studied and 4.5% glucose solution, pH 6.0, yielded stable colloidal solutions with sizes slightly below 100nm for several hours. A single injection of these concentrated siRNA polyplexes into luciferase-expressing human glioblastoma tumors, which were subcutaneously xenografted into nude mice, led to a significant 30% siRNA-mediated luciferase gene silencing 4days post-injection. Our results altogether substantiate the potential of self-assembling cationic polymers with a pH-sensitive disassembly switch for siRNA delivery in vitro and also in vivo experiments. [Display omitted]