title: Synthesis and characterisation of polyamine-poly(ethylene glycol) constructs for DNA binding and gene delivery.
abstract: Improved non-viral vector systems are needed for efficient delivery of DNA to target cell nuclei in gene therapy. A series of linear polyamine poly(ethylene glycol) (PEG) constructs has been synthesised by reaction of appropriately Boc-protected thermine derivatives with omega-methoxyPEG oxiranylmethyl ethers. Constructs carrying 1-3 MeOPEG units and 0, 2 or 4 N-methyl groups have been prepared by this method. H2N(CH2)3NBoc(CH2)3NBoc(CH2)3NHBoc was prepared efficiently by mono-trifluoroacetylation of thermine, attachment of Boc and removal of the trifluoroacetyl group in one pot. A similar process gave H2N(CH2)3NBoc(CH2)3NBoc(CH2)3NH2. BocMeN(CH2)3NHMe was alkylated by 1,3-dibromopropane to give BocMeN(CH2)3NMe(CH2)3NMe(CH2)3NMeBoc. A cyanoethylation/reduction sequence extended H2N(CH2)3NBoc(CH2)3NBoc(CH2)3NH2 to give H2N(CH2)3NBoc(CH2)3NBoc(CH2)3NBoc(CH2)3NBoc(CH2) 3NH2, which was converted to its mono- and di-MeOPEG550 derivatives. Deprotection gave the linear polyamine MeOPEG constructs. A branched triamine-poly(ethylene glycol) construct was prepared by acylation of (BocHN(CH2)3)2N(CH2)3NH2 with omega-methoxyPEG 550 chloroformate, followed by deprotection. A cyanoethylation/reduction/protection sequence from (H2N(CH2)3)2 N(CH2)3NHBoc gave a protected pentamine. Alkylation with Br(CH2)5CONH(CH2)2NHBoc, deprotection, acylation with MeOPEG chloroformate and deprotection gave a pentamine MeOPEG construct in which the MeOPEG is attached through a linker to the central amine. The linear hexamine construct carrying MeOPEG550 at only one terminus was the most effective DNA-interactive member of the two series in an ethidium displacement assay and was effective in delivering a reporter gene to RIF-1 tumours.
authors.affiliation: Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, UK.
authors.forename: S W
authors.initials: SW
authors.lastname: Garrett
authors.forename: O R
authors.initials: OR
authors.lastname: Davies
authors.forename: D A
authors.initials: DA
authors.lastname: Milroy
authors.forename: P J
authors.initials: PJ
authors.lastname: Wood
authors.forename: C W
authors.initials: CW
authors.lastname: Pouton
authors.forename: M D
authors.initials: MD
authors.lastname: Threadgill
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002467:Cell Nucleus / Q000378:metabolism; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000008:administration & dosage / Q000378:metabolism* / Q000648:ultrastructure; D004339:Drug Compounding; D016503:Drug Delivery Systems; D004996:Ethidium / Q000378:metabolism; D005260:Female; D017930:Genes, Reporter / Q000235:genetics; D006801:Humans; D051379:Mice; D008809:Mice, Inbred C3H; D011073:Polyamines / Q000138:chemical synthesis / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000378:metabolism*; D012513:Sarcoma, Experimental / Q000235:genetics / Q000378:metabolism; D013501:Surface-Active Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D014162:Transfection / Q000379:methods
chemical_list: D011073:Polyamines; D013501:Surface-Active Agents; D011092:Polyethylene Glycols; D004247:DNA; D015500:Chloramphenicol O-Acetyltransferase; D004996:Ethidium