Pyridylthiourea-grafted polyethylenimine offers an effective assistance to siRNA-mediated gene silencing in vitro and in vivo.
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 10 nM 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 100 nm 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 4 days 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.
Laboratoire de Conception et Application de Molécules Bioactives, CNRS-Université de Strasbourg UMR 7199, Faculté de Pharmacie, 74, route du rhin, 67400 Illkirch, France.
Gaelle
G
Creusat
Jean-Sébastien
JS
Thomann
Anne
A
Maglott
Bénédicte
B
Pons
Monique
M
Dontenwill
Eric
E
Guérin
Benoit
B
Frisch
Guy
G
Zuber
D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004912:Erythrocytes / Q000187:drug effects / Q000473:pathology; D020868:Gene Silencing; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009369:Neoplasms / Q000378:metabolism; D011094:Polyethyleneimine / Q000008:administration & dosage* / Q000737:chemistry; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000737:chemistry; D012756:Sheep; D013890:Thiourea / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000737:chemistry
D034741:RNA, Small Interfering; D011094:Polyethyleneimine; D013890:Thiourea