Synthesis and characterisation of polyamine-poly(ethylene glycol) constructs for DNA binding and gene delivery.
Bioorg Med Chem 2000;
8:1779-97. [PMID:
10976527 DOI:
10.1016/s0968-0896(00)00113-9]
[Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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.
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