Polycation liposomes, a novel nonviral gene transfer system, constructed from cetylated polyethylenimine

Yamazaki, Yukako; Nango, Mamoru; Matsuura, M; Hirabayashi, Yoko; Hasegawa, Mamoru; Oku, Naoto

doi:10.1038/sj.gt.3301217

Cited by 116 publications

(94 citation statements)

References 39 publications

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“…Phospholipid formulations incorporating lipophilic PEI2 (polycation liposomes) have been recently reported to possess enhanced transfection efficiency compared with PEI2 (39,40). This finding was attributed to liposome anchoring of PEI derivatives resulting in enhanced interaction with the cell membrane, which, in turn, leads to facile endocytosis of the DNA-vector complexes (39,40). These systems, however, are no more efficient than PEI25 in the presence of serum (40).…”

Section: Resultsmentioning

confidence: 99%

Enhancing polyethylenimine's delivery of plasmid DNA into mammalian cells

Thomas

Klibanov

2002

Proc. Natl. Acad. Sci. U.S.A.

467

345

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The effect of various chemical modifications of nitrogen atoms on the efficiency of polyethylenimines (PEIs) as synthetic vectors for the delivery of plasmid DNA into monkey kidney cells in vitro has been systematically investigated. The resultant structureactivity relationship has both provided mechanistic insights and led to PEI derivatives with markedly enhanced performance. For example, N-acylation of PEI with the molecular mass of 25 kDa (PEI25, one of the most potent polycationic gene delivery vectors) with alanine nearly doubles its transfection efficiency in the presence of serum and also lowers its toxicity. Furthermore, dodecylation of primary amino groups of 2-kDa PEI yields a nontoxic polycation whose transfection efficiency in the presence of serum is 400 times higher than the parent's and which exceeds 5-fold even that of PEI25.I nterest in gene therapy has soared in recent years because of its great promise in treating diseases ranging from inherited disorders to acquired conditions and cancer (1-3). However, much progress remains to be made before safe and reliable gene delivery vehicles are developed (4). Side reactions provoked by the viral elements, e.g., immune response and insertional mutagenesis (5), have prompted efforts to improve nonviral delivery systems (vectors) (6-8). Synthetic vectors based on polycations are particularly attractive because of their potential safety, nucleic acid cargo capacity, and designability (9-11). And yet, currently available polycations are severely limited by their low efficiencies (4,8).Improvements in gene delivery by polyplexes (polycation͞ DNA complexes) may come from a detailed examination of their mechanism of action, establishing the underlying structureactivity relationships, and manipulation of the vectors accordingly (12-16). Polyethylenimine (PEI), a readily available synthetic polycation introduced for transfection a few years ago (17), is an ideal candidate for such mechanistic investigations owing to its already relatively high transfection efficiency and ease of functionalization.Elucidation of the mechanism of PEI-mediated gene delivery has received much attention in recent years (18-24). Since every third atom in PEI is a protonatable nitrogen, the overall protonation level should rise when the pH drops to Ϸ5 inside the lysosomal compartment, leading to the influx of chloride ions and, consequently, to osmotic swelling and rupture of the lysosome. The early escape of the PEI͞DNA complex from the lysosome, and thus the avoidance of lysosomal degradation arising from the ''proton sponge effect,'' was postulated to be the cause of the high transfection efficiency exhibited by PEIs (17); this concept, however, has been recently challenged (22).In the present study, we carried out systematic chemical modifications of commercial branched PEIs with the goal of understanding and enhancing PEI-mediated transfection. PEIs with molecular masses of 25 and 2 kDa were selected because they exhibit high and low transfection efficiencies, respectively (17)...

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Section: Resultsmentioning

confidence: 99%

Enhancing polyethylenimine's delivery of plasmid DNA into mammalian cells

Thomas

Klibanov

2002

Proc. Natl. Acad. Sci. U.S.A.

467

345

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“…4,5 Compared to our reference system, Fugene6t, the novel lipids displayed similar or slightly higher cytotoxicity in most cell lines tested in this study. In recent reports, 4 modified liposomes yielded 15-60% viable cells after lipofection.…”

Section: Discussionmentioning

confidence: 97%

“…3 All transduction techniques including lipofection result in cytotoxic side effects. 4 Different ratios of lipids (DOPE, CCQ) were used to attempt the balance of maximal gene transfer efficiency and minimal cytotoxicity.…”

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confidence: 99%

Novel cGMP liposomal vectors mediate efficient gene transfer

et al. 2003

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Viral vector systems are the most commonly used gene transfer tools for clinical gene therapy. However, lipofection systems are potential alternatives because of lower immunogenicity and easier cGMP production, but in vivo stability and transduction efficacy need to be improved. Therefore, we investigated gene transduction efficiency of our novel cGMP cationic lipids, CCQ22 and CCQ32, by FACS analysis. Toxicity analysis was performed to determine the cytotoxic side effects of the novel lipids. To evaluate the stability of the compounds in the context of local delivery to patients with intraperitoneally metastatic ovarian cancer, gene transfer was also tested in the presence of malignant ascites. Our novel cGMP standard lipids mediated gene transfer rates of more than 50%. However, for most cell lines cytotoxic side effects were similar to our reference lipofection system. In general, ascites had no major influence on gene transduction rates with the novel lipids. Our results suggest that CCQs may compare favorably with commercially available lipofection systems. These promising results facilitate further analysis of the compounds.

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“…Conjugation of the polyamine and hydrophobic portions is required for an effective gene carrier (Figure 4). Such amphiphilicity is essential www.intechopen.com Polyamine -Lipid Conjugates as Effective Gene Carriers: Chemical Structure, Morphology, and Gene Transfer Activity 255 to condense DNA molecules, which requires both electrostatic and hydrophobic interactions (Yamazaki, 2000;Dewa et al, 2004a,b). We tested a number of combinations of dialkyl and polyamine portions for their activity in gene transfection.…”

Section: Chemical Structure Of the Polyamine Conjugatesmentioning

confidence: 99%

“…In addition to investigation of intracellular trafficking of polycation-DNA complexes (polyplexes and lipoplexes), observation of morphology and metamorphosis of the complexes is very important to shed light on the mechanism of gene transfer and provide information for development of novel synthetic carriers (Koynova, Wang & MacDonald, 2006;Wan et al, 2008;Tarahovsky, Koynova & MacDonald, 2004). We have reported that polycationic liposomes (PCL) containing cetylated polyethylenimine (cetyl-PEI) possess high gene transfer activity (Yamazaki et al, 2000;Oku et al, 2001;Matsuura et al, 2003). The cetyl-PEI molecule is anchored by the hydrophobic cetyl portion and is distributed over the liposomal surface.…”

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confidence: 99%