title: PEGylation of biodegradable dextran nanogels for siRNA delivery.
abstract: Delivering intact small interfering RNA (siRNA) into the cytoplasm of targeted cells in vivo is considered a major obstacle in the development of clinically applicable RNA interference-based therapies. Although dextran hydroxyethyl methacrylate (dex-HEMA) nanogels have been reported to be suitable carriers for siRNA delivery in vitro, and are ideally sized (approximately 180 nm) for intravenous delivery to tumors, they likely possess insufficient blood circulation times to enable an adequate extravasation and accumulation in the tumor tissue. PEGylation of these nanogels should not only improve their circulation time but also minimize their aggregation upon intravenous injection. For this reason, a new type of nanogels and three different methods of PEGylating dextran nanogels were evaluated. Covalent PEGylation of the siRNA-loaded nanogels using N-hydroxysuccinimidyl polyethylene glycol (NHS-PEG) was shown to be superior to the addition of both polyethylene glycol (PEG) and PEG grafted poly-l-glutamic acid (PGA-PEG). Flow cytometry and confocal microscopy revealed that PEGylated nanogels are still taken up efficiently by HuH-7 human hepatoma cells and A431 human epithelial carcinoma cells and that the process is cell type dependent. Moreover, PEGylated nanogels loaded with siRNA cause significant EGFP knockdown in a human hepatoma cell line (HuH-7_EGFP) and are non-toxic for these cells.
authors.affiliation: Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium.
authors.forename: B
authors.initials: B
authors.lastname: Naeye
authors.forename: K
authors.initials: K
authors.lastname: Raemdonck
authors.forename: K
authors.initials: K
authors.lastname: Remaut
authors.forename: B
authors.initials: B
authors.lastname: Sproat
authors.forename: J
authors.initials: J
authors.lastname: Demeester
authors.forename: S C
authors.initials: SC
authors.lastname: De Smedt
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy / Q000378:metabolism; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability; D002470:Cell Survival / Q000187:drug effects; D003911:Dextrans / Q000009:adverse effects / Q000737:chemistry* / Q000378:metabolism*; D004337:Drug Carriers / Q000008:administration & dosage / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology; D016503:Drug Delivery Systems; D005434:Flow Cytometry; D020868:Gene Silencing / Q000187:drug effects; D017930:Genes, Reporter / Q000187:drug effects; D006801:Humans; D020100:Hydrogels; D008113:Liver Neoplasms / Q000188:drug therapy / Q000378:metabolism; D008689:Methacrylates / Q000009:adverse effects / Q000737:chemistry / Q000378:metabolism; D018613:Microscopy, Confocal; D049329:Nanostructures / Q000009:adverse effects / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000009:adverse effects / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D011099:Polyglutamic Acid / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology; D013388:Succinimides / Q000737:chemistry
chemical_list: D000970:Antineoplastic Agents; D003911:Dextrans; D004337:Drug Carriers; D020100:Hydrogels; D008689:Methacrylates; D034741:RNA, Small Interfering; D013388:Succinimides; C508284:dextran hydroxyethyl methacrylate; C514458:methacrylated dextran; D011099:Polyglutamic Acid; D011092:Polyethylene Glycols