Synthesis and characterisation of polyamine-poly(ethylene glycol) constructs for DNA binding and gene delivery

• Published in: Bioorganic & medicinal chemistry 2000-07, Vol.8 (7), p.1779-1797
• Main Authors: GARRETT, S. W, DAVIES, O. R, MILROY, D. A, WOOD, P. J, POUTON, C. W, THREADGILL, M. D
• Format: Article
• Language: English
• Subjects: Animals; Binding, Competitive; Biological and medical sciences; Biotechnology; Cell Nucleus - metabolism; Chloramphenicol O-Acetyltransferase - genetics; Chloramphenicol O-Acetyltransferase - metabolism; DNA - administration & dosage; DNA - metabolism; DNA - ultrastructure; Drug Compounding; Drug Delivery Systems; Ethidium - metabolism; Female; Fundamental and applied biological sciences. Psychology; Gene therapy; Genes, Reporter - genetics; Health. Pharmaceutical industry; Humans; Industrial applications and implications. Economical aspects; Mice; Mice, Inbred C3H; Polyamines - chemical synthesis; Polyamines - metabolism; Polyethylene Glycols - chemical synthesis; Polyethylene Glycols - metabolism; Sarcoma, Experimental - genetics; Sarcoma, Experimental - metabolism; Surface-Active Agents - chemical synthesis; Surface-Active Agents - chemistry; Surface-Active Agents - metabolism; Transfection - methods
• ISSN: 0968-0896; 1464-3391
• DOI: 10.1016/S0968-0896(00)00113-9

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.