Electrophoretic purification of tumor-targeted polyethylenimine-based polyplexes reduces toxic side effects in vivo

Fahrmeir, Julia; Günther, Michael; Tietze, Nicole; Wagner, Ernst; Ogris, Manfred

doi:10.1016/j.jconrel.2007.05.013

Cited by 54 publications

(36 citation statements)

References 33 publications

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“…However, combinations of initiator and executor caspases were not examined in these viral applications. Separate investigations have used PEI as a gene delivery vehicle for in vivo cancer research, demonstrating its potential as a vector for living organisms [54,55].…”

Section: Discussionmentioning

confidence: 99%

Comparison of Caspase Genes for the Induction of Apoptosis Following Gene Delivery

2008

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The polycation poly(ethylenimine) (PEI) was used to deliver the plasmids coding for various combinations of caspases to Cox-2 overexpressing cancer cell lines. It was found that the expression of the delivered genes, controlled by the Cox-2 promoter, correlated with the expression of the endogenous Cox-2 gene in each cell line in a relatively linear manner. Among the various caspase combination regimens, the combination of caspase 3 plus caspase 9 proved to be the most effective because of an apparent synergy between the two gene products, and produced phosphatidylserine flipping in addition to fragmentation of genomic DNA. Caspase 1 appeared to work independently of either caspases 3 or 9, as no synergistic effect was observed. Transfections with genes coding for granzyme B and caspase 8 yielded a lesser amount of cell death. The delivery of a combination of caspase genes could be readily moved to in vivo research of bladder and colon cancer treatments, and holds great applicability to a wide array of additional tumor types.

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Section: Discussionmentioning

confidence: 99%

Comparison of Caspase Genes for the Induction of Apoptosis Following Gene Delivery

2008

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“…As reported previously, the cytotoxicity of nucleic acid/polymer polyplexes is attributed to free cationic polymers. [55][56][57][58] Therefore, the significantly higher cytotoxicity of the GFP plasmid DNA/PEI polyplexes prepared by adding PEI to plasmid DNA (Fig. 5C) can also be explained by free PEI in excess upon complete complexation (Fig.…”

Section: A Model For Nucleic Acid Complexation By Cationic Polymersmentioning

confidence: 97%

Mixing-sequence-dependent nucleic acid complexation and gene transfer efficiency by polyethylenimine

et al. 2015

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Polyplexes, complexed nucleic acids by cationic polymers, are the most common forms of nonviral gene delivery vectors. In contrast to a great deal of efforts in synthesizing novel cationic polymers and exploring their extracellular and intracellular delivery pathways, polyplex preparation methods of mixing nucleic acids and cationic polymers are often overlooked. In this study, the mixing sequence, that is adding nucleic acids to polymers or vice versa, was found to greatly affect complexation of both plasmid DNA and siRNA, polyplexes' size, and polyplexes' surface charge, which all collaboratively affected the transfection efficiency and cytotoxicity. Adding polyethylenimine (PEI), the most conventionally used standard in nonviral gene delivery, to plasmid DNA and siRNA resulted in larger polyplexes, higher gene expression and silencing, but higher cytotoxicity than polyplexes prepared in the reverse order. Based on the experimental results, the authors developed a model that gradual addition of cationic polymers (e.g., PEI) to nucleic acids (e.g., plasmid DNA and siRNA) incorporates more copies of nucleic acids in larger polyplexes in a smaller number, results in higher gene expression and silencing levels in transfected cells, and generates higher cytotoxicity by leaving more free polymers upon complete mixing than the other mixing sequence. The proposed model can be explored using a broad range of cationic polymers and nucleic acids, and provide insightful information about how to prepare polyplexed nonviral vectors for efficient and safe gene delivery.

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“…(Boeckle et al, 2004;Fahrmeir et al, 2007;Hanzlikova et al, 2011;Yue et al, 2011) Kichler et al reported that PEI has no effect on cell membranes. (Kichler et al, 2001) However, the underlying experiments were carried out in citrate buffer, and the PEI was hence sequestered into an uncharged PEI-citrate complex (Eberhardy et al, 2009), so no free polymer was present.…”

Section: Introductionmentioning

confidence: 99%

Cytotoxicity of polycations: Relationship of molecular weight and the hydrolytic theory of the mechanism of toxicity

Monnery

Wright

Cavill

et al. 2017

International Journal of Pharmaceutics

167

162

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The mechanism of polycation cytotoxicity and the relationship to polymer molecular weight is poorly understood. To gain an insight into this important phenomenon a range of newly synthesized uniform (near monodisperse) linear polyethylenimines, commercially available poly(L-lysine)s and two commonly used PEI-based transfectants (broad 22 kDa linear and 25 kDa branched) were tested for their cytotoxicity against the A549 human lung carcinoma cell line. Cell membrane damage assays (LDH release) and cell viability assays (MTT) showed a strong relationship to dose and polymer molecular weight, and increasing incubation times revealed that even supposedly "non-toxic" low molecular weight polymers still damage cell membranes. The newly proposed mechanism of cell membrane damage is acid catalysed 3 hydrolysis of lipidic phosphoester bonds, which was supported by observations of the hydrolysis of DOPC liposomes.

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Electrophoretic purification of tumor-targeted polyethylenimine-based polyplexes reduces toxic side effects in vivo

Cited by 54 publications

References 33 publications

Comparison of Caspase Genes for the Induction of Apoptosis Following Gene Delivery

Comparison of Caspase Genes for the Induction of Apoptosis Following Gene Delivery

Mixing-sequence-dependent nucleic acid complexation and gene transfer efficiency by polyethylenimine

Cytotoxicity of polycations: Relationship of molecular weight and the hydrolytic theory of the mechanism of toxicity

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