A Physicochemical Approach for Predicting the Effectiveness of Peptide-Based Gene Delivery Systems for Use in Plasmid-Based Gene Therapy

Duguid, J.G.; Li, Cynthia; Shi, Mei; Logan, Mark; Alila, Hector W.; Rolland, Alain; Tomlinson, E.; Sparrow, James T.; Smith, Louis C.

doi:10.1016/s0006-3495(98)77987-1

Cited by 100 publications

(61 citation statements)

References 74 publications

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“…However, this strategy fails when using LMW peptides as DNA condensing agents, because, at all charge ratios, these peptides are rapidly stripped during circulation because of their lower DNA binding affinity relative to HMW polylysine (18). If LMW peptides are to be useful as in vivo gene transfer agents, it is critical to improve their design to form small (Ͻ100-nm diameter) metabolically stable DNA condensates with the desired surface charge (31).…”

Section: Discussionmentioning

confidence: 99%

A Potent New Class of Reductively Activated Peptide Gene Delivery Agents

McKenzie

Kwok

Rice

2000

Journal of Biological Chemistry

243

212

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A new class of peptide gene delivery agents were developed by inserting multiple cysteine residues into short (dp 20) synthetic peptides. Substitution of one to four cysteine residues for lysine residues in Cys-TrpLys 18 resulted in low molecular weight DNA condensing peptides that spontaneously oxidize after binding to plasmid DNA to form interpeptide disulfide bonds. The stability of cross-linked peptide DNA condensates increased in proportion to the number of cysteines incorporated into the peptide. Disulfide bond formation led to a decrease in particle size relative to control peptide DNA condensates and prevented dissociation of peptide DNA condensates in concentrated sodium chloride. Cross-linked peptide DNA condensates were 5-60-fold more potent at mediating gene expression in HepG2 and COS 7 cells relative to uncross-linked peptide DNA condensates. The enhanced gene expression was dependent on the number of cysteine residues incorporated, with a peptide containing two cysteines mediating maximal gene expression. Cross-linking peptides caused elevated gene expression without increasing DNA uptake by cells, suggesting a mechanism involving intracellular release of DNA triggered by disulfide bond reduction. The results establish cross-linking peptides as a novel class of potent gene delivery agents that enhance gene expression through a new mechanism of action.A variety of nonviral gene delivery carriers have been developed and tested as in vitro transfection agents used to transiently express foreign DNA. Cationic lipids (1, 2), polylysine peptides (3-5), and cationic polymers such as polyethylenimine (6, 7) bind electrostatically to the phosphate backbone of DNA forming complexes that mediate cellular uptake of DNA in culture.As opposed to the success of these agents in vitro, attempted in vivo use has revealed many complications related to their toxicity (8), antigenicity (9), complement activation (10), solubility (11), blood compatibility (12), and stability (13). These complications relate to the size and charge of DNA carrier complexes and ultimately to the molecular characteristics of the carrier itself. High molecular weight (HMW) 1 DNA carriers can be cytotoxic (8), are able to activate the complement system (10), and can elicit an immune response (9). The size and heterogeneity of these polymers also significantly complicates region-specific derivatization with ligands or polyethylene glycol (14).To circumvent these problems, several low molecular weight (LMW) carrier peptides have been developed that mediate in vitro gene transfer as efficiently as their HMW counterparts (15-17). They offer the advantage of controlled synthesis and defined purity that then allows strategic optimization to increase expression levels and eliminate side effects.However, when analyzed for in vivo efficacy, LMW peptide DNA condensates lacked sufficient stability to survive circulation, were not able to significantly protect DNA from metabolism, and could not effect targeting (13,18). One solution to increase LMW pept...

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Section: Discussionmentioning

confidence: 99%

A Potent New Class of Reductively Activated Peptide Gene Delivery Agents

McKenzie

Kwok

Rice

2000

Journal of Biological Chemistry

243

212

View full text Add to dashboard Cite

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“…2 Three approaches are mainly used for the insertion of marker or "therapeutic" genes into cDNA: (1) application of recombinant viral vectors; (2) physical transfection methods (such as electroporation, DNA injections, "gene gun" method, and others); and (3) the application of nonviral systems for the DNA delivery to cells [5,6]. The carriers on the basis of recombinant viruses (e.g., adenovirus ADV), retroviruses (RV), and herpes simplex type 1 virus (HSV-1) have a number of advantages over the other delivery methods due to their high specificity to certain types of tissues and their ability to be effectively transfected.…”

Section: Introductionmentioning

confidence: 99%

Cationic oligopeptides modified with lipophilic fragments: Use for DNA delivery to cells

et al. 2005

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Cationic oligopeptides, including the amphipathic α -helical peptides, are applied to the targeted delivery of DNA to eukaryotic cells due to their DNA-compacting properties and the ability to destabilize the cell lipid bilayer in some cases. We synthesized the peptides differing in the number and location of residues of decanoic acid covalently attached to Lys residues in order to combine the DNA-binding and the membrane activities in a single molecule. We chose peptide structures that assisted in the formation of α helices. The DNAbinding ability of the peptides and the membrane activity of their complexes with DNA were shown to depend on the structure. The study of erythrocyte hemolysis by complexes with DNA of the pCMV LacZ plasmid and the peculiarities of transfection of these complexes revealed a correlation between the hemolytic activity and the expression level of the lacZ gene in cells.

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“…Second, the transfection efficiency needs to be increased and/or expression of transgenes with increased potency needs to be optimized to completely suppress tumor growth rather than simply decrease the growth rate. Examples of technology that can overcome these limitations are reduction of nonspecific cell interactions with masking technologies, such as incorporating polyethylene glycol; transfection complex targeting with ligands to yield selective uptake to tumor vasculature; coformulation of agents to facilitate endocytic vacuole escape of the delivered gene, such as pH-dependent lytic peptides 21,22 or proton-absorbing polymers; 23 and increased nuclear uptake of the plasmid either by incorporating nuclear localization agents 24 or by simply including DNA sequences that endogenous nuclear localization proteins can recognize. 25 There are several alternative types of genes that can be expressed with increased potency.…”

Section: Discussionmentioning

confidence: 99%

Cationic lipid-based delivery system for systemic cancer gene therapy

et al. 2000

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A cationic lipid-based gene delivery system composed of N- [(1-(2,3-dioleyloxy)propyl)]-N-N-N-trimethylammonium chloride and cholesterol, at a 4:1 molar ratio, was developed for systemic administration. Plasmid biodistribution and expression were characterized in syngeneic mouse tumor model squamous cell carcinoma VII cells. A reporter gene expression plasmid was used for biodistribution of plasmid and expression. The results showed that lungs and primary tumors were transfected. Fluorescence microscopy showed that fluorescent-labeled transfection complexes were passively targeted to the tumor vasculature and that the endothelial cells internalized the plasmid. Transgene expression was characterized based on duration of expression and dosing schedule. In vivo gene transfer with an interleukin-12 expression plasmid yielded protein levels in blood, lungs, and primary tumor after intravenous administration. Efficacy studies showed that 15 g of interleukin-12 plasmid was sufficient to produce a gene-specific inhibition of primary tumor growth. These results characterize the vascularity of the tumor model, characterize the in vivo gene transfer properties of the plasmid-based gene delivery system, and show that the transgene expression level was sufficient to elicit a biological response by inhibiting tumor growth.

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A Physicochemical Approach for Predicting the Effectiveness of Peptide-Based Gene Delivery Systems for Use in Plasmid-Based Gene Therapy

Cited by 100 publications

References 74 publications

A Potent New Class of Reductively Activated Peptide Gene Delivery Agents

A Potent New Class of Reductively Activated Peptide Gene Delivery Agents

Cationic oligopeptides modified with lipophilic fragments: Use for DNA delivery to cells

Cationic lipid-based delivery system for systemic cancer gene therapy

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