Polymer‐coated polyethylenimine/DNA complexes designed for triggered activation by intracellular reduction

Carlisle, Robert; Etrych, Tomáš; Briggs, Simon S.; Preece, Jon A.; Ulbrich, Karel; Seymour, Leonard W.

doi:10.1002/jgm.525

Cited by 110 publications

(69 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When transfecting cells with low NADPH/H ϩ levels with lPEI polyplexes as a control, the efficacy was not affected at any time point (data not shown). Therefore, from the literature and our results, we conclude that the polyplexes may at least partially undergo an NADPH/H ϩ -dependent, and therefore GSH-dependent, reduction inside the cell (28)(29)(30). The data in Fig.…”

Section: Resultssupporting

confidence: 73%

Breaking up the correlation between efficacy and toxicity for nonviral gene delivery

Breunig

Lungwitz

Liebl

et al. 2007

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

405

322

View full text Add to dashboard Cite

Nonviral nucleic acid delivery to cells and tissues is considered a standard tool in life science research. However, although an ideal delivery system should have high efficacy and minimal toxicity, existing materials fall short, most of them being either too toxic or little effective. We hypothesized that disulfide cross-linked lowmolecular-weight (MW) linear poly(ethylene imine) (MW <4.6 kDa) would overcome this limitation. Investigations with these materials revealed that the extracellular high MW provided outstandingly high transfection efficacies (up to 69.62 ؎ 4.18% in HEK cells). We confirmed that the intracellular reductive degradation produced mainly nontoxic fragments (cell survival 98.69 ؎ 4.79%). When we compared the polymers in >1,400 individual experiments to seven commercial transfection reagents in seven different cell lines, we found highly superior transfection efficacies and substantially lower toxicities. This renders reductive degradation a highly promising tool for the design of new transfection materials.biodegradable ͉ polyethylenimine ͉ nucleic acid ͉ disulfide bond ͉ transfection G ene transfer into cells has become a standard procedure in life science research. Nonviral carriers have gained in importance in recent years because of their safety in handling and ease of application compared with viral vectors. Browsing databases such as PubMed or Chemical Abstracts reveals that almost every publication related to genetics, biochemistry, molecular biology, developmental biology, or neurology incorporated lipid-or polymer-based transfection as a pivotal tool for the investigation of various cellular processes. Therefore, it appears that the delivery of nucleic acids is a well established method for the transfection of mammalian cells, and, given the amount of research data that has been produced, one would assume that the procedures for nonviral transfection would be well optimized. A closer look at the contemporary literature, however, reveals that doubts seem justified. Contemporary transfection reagents are almost universally toxic because of their cationic or amphiphilic character (1-4).The dilemma that we face is exemplified by considering the polymeric transfection agent poly(ethylene imine) (PEI). Since its introduction in 1995, PEI has been considered the gold standard for polymer-based gene carriers because of the relatively high transfection efficacy of its polyplexes (complex of nucleic acid and polymer) (5, 6). However, it has been shown that both the efficacy and toxicity of PEI are strongly correlated with its molecular weight (MW) as well as its structure (branched or linear: bPEI or lPEI, respectively) (7-17). Efficacy and adverse reactions seem thereby to be strongly associated. PEI is not the only material that suffers from this ''malignant'' correlation. Nonviral transfection seems like choosing between Scylla and Charybdis: either a high transfection efficacy, which is associated with a devastating toxicity, or a low efficacy, which does not affect the cell viability at ...

show abstract

Section: Resultssupporting

confidence: 73%

Breaking up the correlation between efficacy and toxicity for nonviral gene delivery

Breunig

Lungwitz

Liebl

et al. 2007

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

405

322

View full text Add to dashboard Cite

show abstract

“…20 The concentration of the DOX released into the medium was determined using a UV-spectrophotometer (UV spectrophotometer 1201, Shimadzu Co. Japan) at 488 nm. 21 To study the effects of a reducing environment on drug release from these particles, a simulated environment similar to that of cytosol was created according to Carlisle et al 22 by the addition of 0.01% threo-1,4-dimercapto-2,3-butandiol (DTT) as a reducing agent to PBS medium replacing PBS in the above experiment. The release data in this medium were obtained and compared with PBS medium data.…”

Section: Drug-loading and Drug-release Studiesmentioning

confidence: 99%

“…The release of drug from particles was examined in PBS (pH 7.4). In a second experiment the release studies were performed under reducing conditions achieved by 0.01% DTT, simulating intracellular redox conditions of cytosol as described previously by Carlisle et al 28 There was a controlled release pattern during 15 hours for all the …”

Section: Drug-loading and Drug-release Studiesmentioning

confidence: 99%

Thiolated chitosan nanoparticles as a delivery system for antisense therapy: evaluation against EGFR in T47D breast cancer cells

Talaei

Azizi²,

Dinarvand³

et al. 2011

IJN

View full text Add to dashboard Cite

Thiolated chitosan has high transfection and mucoadhesive properties. We investigated the potential of two recently synthesized polymers: NAC-C (N-acetyl cysteine-chitosan) and NAP-C (N-acetyl penicillamine-chitosan) in anticancer drug delivery targeting epidermal growth factor receptor (EGFR). Doxorubicin (DOX) and antisense oligonucleotide (ASOND)-loaded polymer nanoparticles were prepared in water by a gelation process. Particle characterization, drug loading, and drug release were evaluated. To verify drug delivery efficiency in vitro experiments on a breast cancer cell line (T47D) were performed. EGFR gene and protein expression was analyzed by real time quantitative polymerase chain reaction and Western blotting, respectively. A loading percentage of 63% ± 5% for ASOND and 70% ± 5% for DOX was achieved. Drug release data after 15 hours showed that ASOND and DOX were completely released from chitosan-based particles while a lower and more sustained release of only 22% ± 8% was measured for thiolated particles. In a cytosol simulated release medium/reducing environment, such as found intracellularly, polymer-based nanoparticles dissociated, liberating approximately 50% of both active substances within 7 hours. ASOND-loaded polymer nanoparticles had higher stability and high mucoadhesive properties. The ASOND-loaded thiolated particles significantly suppressed EGFR gene expression in T47D cells compared with ASOND-loaded chitosan particles and downregulated EGFR protein expression in cells. This study could facilitate future investigations into the functionality of NAP-C and NAC-C polymers as an efficient ASOND delivery system in vitro and in vivo.

show abstract

“…This polyplex is stabilised using disulphide bonds, enabling triggered disassembly and unpackaging within the reducing intracellular environment. 17,28 Intact wild-type adenovirus or FGF retargeted polyplex/AdwtDNA-TP was delivered to A549 cells (0.1-10 000 genome copies per cell) in the presence of neutralising antisera. The infection media/antisera were then removed and cells were incubated in fresh medium.…”

Section: Antibody-resistant Delivery Of Adenovirus Virotherapymentioning

confidence: 99%

“…16 Recently, we have developed synthetic polymer-based delivery vectors designed to combine robust stability during the delivery phase with activation by reduction following entry into cells, enabling triggered disassembly and cell-specific expression of transgenes. 17 However, despite attractive pharmaceutical properties, the usefulness of synthetic vectors is usually limited by the low levels of transgene expression they achieve.…”

Section: Introductionmentioning

confidence: 99%

Use of synthetic vectors for neutralising antibody resistant delivery of replicating adenovirus DNA

et al. 2006

View full text Add to dashboard Cite

Use of synthetic vectors to deliver genomes of conditionally replicating lytic viruses combines the strengths of viral and non-viral approaches by enabling neutralising antibody resistant deployment of cancer virotherapy. Adenovirus is particularly suitable for this application since all proteins essential for replication can be expressed from the input DNA, although the presence of terminal protein (TP) covalently linked to the 5 0 termini of the input virus genomes both improves expression of transgenes encoded in the input DNA and also enhances replication. These roles of TP were distinguished in experiments where E1-deleted Ad GFP DNA bearing TP (Ad GFP DNA-TP), delivered with DOTAP, gave a two-fold greater frequency of transduction than Ad GFP DNA(without TP) in non-complementing A549 cells, while in 293 cells (which support replication of E1-deleted viruses) the presence of TP mediated a much greater differential transgene expression, commensurate with its ability to promote replication. Subsequent studies using AdDNA for virotherapy, therefore, included covalently linked TP. AdDNA-TP delivered to A549 cells using a synthetic polyplex vector was shown to be resistant to levels of neutralising antisera that completely ablated infection by wild-type adenovirus, enabling polyplex/ Ad wild type DNA-TP to mediate a powerful cytopathic effect. Similarly in vivo, direct injection of a polyplex/Ad wild type DNA-TP into A549 tumours was neutralising antibodyresistant and enabled virus replication, whereas intact virus was neutralised by the antibody and failed to infect. The delivery of adenovirus genomes-TP using synthetic vectors should provide a strategy to bypass neutralising antibodies and facilitate clinical application of replicating adenovirus for cancer virotherapy. Gene Therapy (2006) 13, 1579-1586.

show abstract

Polymer‐coated polyethylenimine/DNA complexes designed for triggered activation by intracellular reduction

Abstract: Linkage of hydrophilic polymer coating to PEI/DNA complexes via reducible disulphide bonds offers a means of fulfilling the contradictory requirements for extracellular stability and intracellular activity.

Cited by 110 publications

References 33 publications

Breaking up the correlation between efficacy and toxicity for nonviral gene delivery

Breaking up the correlation between efficacy and toxicity for nonviral gene delivery

Thiolated chitosan nanoparticles as a delivery system for antisense therapy: evaluation against EGFR in T47D breast cancer cells

Use of synthetic vectors for neutralising antibody resistant delivery of replicating adenovirus DNA

Contact Info

Product

Resources

About