A new method for mammalian cell transformation is proposed which is based on incorporation of plasmids into interpolyelectrolyte complexes (IPECs) with carbon chain polycations. The method is illustrated by examples of pRSV CAT and p beta-Gal plasmid IPECs with poly(N-ethyl-4-vinylpyridinium bromide) (C2PVP) and poly(N-ethyl-4-vinylpyridinium)-poly(N-cetyl-4-vinylpyridinium+ ++) bromides random copolymer (C16PVP). These IPECs are produced spontaneously due to formation of a cooperative system of interchain electrostatic bonds after mixing DNA and polycation solutions. The interaction of IPEC with normal mouse fibroblasts NIH 3T3, human T-lymphoma "Jurkat", and Mardin Darby canine kidney cells has been studied. The data obtained has revealed that plasmid incorporation into IPECs significantly enhances both DNA adsorption on the plasma membrane and DNA uptake into a cell. The in vitro transformation of NIH 3T3 cells was monitored by a standard cloramphenicol acetyltransferase (CAT) assay (pRSV CAT plasmid) and by detection of beta-galactosidase (beta-Gal) expression using 4-methylumbeliferril beta-D-galactopyranoside as a substrate (p beta-Gal plasmid). In both cases it has been proved that IPEC-incorporated plasmids possess an ability for efficient cell transformation. The transforming activity of IPECs depends on their composition and polycation chemical structure. Under optimal conditions the efficiency of cell transformation with IPECs is several fold higher than that observed during standard calcium phosphate precipitation. The mechanism of the phenomenon observed is discussed.(ABSTRACT TRUNCATED AT 250 WORDS)

Polyelectrolyte complexes formed between DNA and poly(N-ethyl-4-vinylpyridinium) cations were shown to effectively transfect mammalian ceils [7]. This work suggests that the polycation-mediated uptake of the plasmid DNA and cell transfection are significantly enhanced when these complexes are administered simultaneously with a poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) copolymer, Pluronic P85. The uptake studies were performed using radioactively labeled pRSV CAT plasmid on NIH 3T3, MDCK, and Jurkat cell lines. The transfection was investigated by ehloramphenicol acetyltransferase assay using 3T3 cells as a model. The effects reported may be useful for the enhancement of the polycation-mediated cell transfection.cytic compartments in the cytoplasm and nucleus of cells [1 3]. Further, due to charge neutralization these complexes are often unstable in aqueous solutions and precipitate, thereby hindering their application in gene delivery [3 8]. One approach recently advanced for drug delivery of water insoluble compounds involves the use of micelles of Pluronic block copolymers [9,10]. Recent work on these systems suggests that they enhance the transport of charged molecules across cell membranes [11,12]. This paper reports a significant increase in cell uptake and transfection of mammalian cells using a combination of DNA-PEVP complexes and micelles of Pluronic P85 block copolymer.