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Cullis PR, Felgner PL. The 60-year evolution of lipid nanoparticles for nucleic acid delivery. Nat Rev Drug Discov 2024; 23:709-722. [PMID: 38965378 DOI: 10.1038/s41573-024-00977-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2024] [Indexed: 07/06/2024]
Abstract
Delivery of genetic information to the interior of target cells in vivo has been a major challenge facing gene therapies. This barrier is now being overcome, owing in part to dramatic advances made by lipid-based systems that have led to lipid nanoparticles (LNPs) that enable delivery of nucleic acid-based vaccines and therapeutics. Examples include the clinically approved COVID-19 LNP mRNA vaccines and Onpattro (patisiran), an LNP small interfering RNA therapeutic to treat transthyretin-induced amyloidosis (hATTR). In addition, a host of promising LNP-enabled vaccines and gene therapies are in clinical development. Here, we trace this success to two streams of research conducted over the past 60 years: the discovery of the transfection properties of lipoplexes composed of positively charged cationic lipids complexed with nucleic acid cargos and the development of lipid nanoparticles using ionizable cationic lipids. The fundamental insights gained from these two streams of research offer potential delivery solutions for most forms of gene therapies.
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Affiliation(s)
- P R Cullis
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada.
| | - P L Felgner
- Department of Physiology & Biophysics, University of California, Irvine, CA, USA.
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2
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Zanardi TA, Korbmacher B, Boone L, Engelhardt JA, Wang Y, Burel S, Prill B, Aghajan M, Guo S, Henry SP. Safety, Pharmacokinetic, and Pharmacodynamic Evaluation of a 2'-(2-Methoxyethyl)-D-ribose Antisense Oligonucleotide-Triantenarry N-Acetyl-galactosamine Conjugate that Targets the Human Transmembrane Protease Serine 6. J Pharmacol Exp Ther 2021; 377:51-63. [PMID: 33431610 DOI: 10.1124/jpet.120.000222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 01/05/2021] [Indexed: 01/29/2023] Open
Abstract
Cellular uptake of antisense oligonucleotides (ASOs) is one of the main determinants of in vivo activity and potency. A significant advancement in improving uptake into cells has come through the conjugation of ASOs to triantenarry N-acetyl-galactosamine (GalNAc3), a ligand for the asialoglycoprotein receptor on hepatocytes. The impact for antisense oligonucleotides, which are already taken up into hepatocytes, is a 10-fold improvement in potency in mice and up to a 30-fold potency improvement in humans, resulting in overall lower effective dose and exposure levels. 2'-Methoxyethyl-modified antisense oligonucleotide conjugated to GalNAc3 (ISIS 702843) is specific for human transmembrane protease serine 6 and is currently in clinical trials for the treatment of β-thalassemia. This report summarizes a chronic toxicity study of ISIS 702843 in nonhuman primates (NHPs), including pharmacokinetic and pharmacology assessments. Suprapharmacologic doses of ISIS 702843 were well tolerated in NHPs after chronic dosing, and the data indicate that the overall safety profile is very similar to that of the unconjugated 2'-(2-methoxyethyl)-D-ribose (2'-MOE) ASOs. Notably, the GalNAc3 moiety did not cause any new toxicities nor exacerbate the known nonspecific class effects of the 2'-MOE ASOs. This observation was confirmed with multiple GalNAc3-MOE conjugates by querying a data base of monkey studies containing both GalNAc3-conjugated and unconjugated 2'-MOE ASOs. SIGNIFICANCE STATEMENT: This report documents the potency, pharmacology, and overall tolerability profile of a triantenarry N-acetyl-galactosamine (GalNAc3)-conjugated 2'-(2-methoxyethyl)-D-ribose (2'-MOE) antisense oligonucleotide (ASO) specific to transmembrane protease serine 6 after chronic treatment in the cynomolgus monkey. Collective analysis of 15 independent GalNAc3-conjugated and unconjugated 2'-MOE ASOs shows the consistency in the dose response and character of hepatic and platelet tolerability across sequences that will result in much larger safety margins for the GalNAc3-conjugated 2'-MOE ASOs when compared with the unconjugated 2'-MOE ASOs given the increased potency.
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Affiliation(s)
- Thomas A Zanardi
- Ionis Pharmaceuticals, Carlsbad, California (T.A.Z., J.A.E., Y.W., S.B., B.P., M.A., S.G., S.P.H.), and Covance Preclinical Services GmbH, Munster, Germany (B.K., L.B.)
| | - Birgit Korbmacher
- Ionis Pharmaceuticals, Carlsbad, California (T.A.Z., J.A.E., Y.W., S.B., B.P., M.A., S.G., S.P.H.), and Covance Preclinical Services GmbH, Munster, Germany (B.K., L.B.)
| | - Laura Boone
- Ionis Pharmaceuticals, Carlsbad, California (T.A.Z., J.A.E., Y.W., S.B., B.P., M.A., S.G., S.P.H.), and Covance Preclinical Services GmbH, Munster, Germany (B.K., L.B.)
| | - Jeffrey A Engelhardt
- Ionis Pharmaceuticals, Carlsbad, California (T.A.Z., J.A.E., Y.W., S.B., B.P., M.A., S.G., S.P.H.), and Covance Preclinical Services GmbH, Munster, Germany (B.K., L.B.)
| | - Yanfeng Wang
- Ionis Pharmaceuticals, Carlsbad, California (T.A.Z., J.A.E., Y.W., S.B., B.P., M.A., S.G., S.P.H.), and Covance Preclinical Services GmbH, Munster, Germany (B.K., L.B.)
| | - Sebastien Burel
- Ionis Pharmaceuticals, Carlsbad, California (T.A.Z., J.A.E., Y.W., S.B., B.P., M.A., S.G., S.P.H.), and Covance Preclinical Services GmbH, Munster, Germany (B.K., L.B.)
| | - Bobby Prill
- Ionis Pharmaceuticals, Carlsbad, California (T.A.Z., J.A.E., Y.W., S.B., B.P., M.A., S.G., S.P.H.), and Covance Preclinical Services GmbH, Munster, Germany (B.K., L.B.)
| | - Mariam Aghajan
- Ionis Pharmaceuticals, Carlsbad, California (T.A.Z., J.A.E., Y.W., S.B., B.P., M.A., S.G., S.P.H.), and Covance Preclinical Services GmbH, Munster, Germany (B.K., L.B.)
| | - Shuling Guo
- Ionis Pharmaceuticals, Carlsbad, California (T.A.Z., J.A.E., Y.W., S.B., B.P., M.A., S.G., S.P.H.), and Covance Preclinical Services GmbH, Munster, Germany (B.K., L.B.)
| | - Scott P Henry
- Ionis Pharmaceuticals, Carlsbad, California (T.A.Z., J.A.E., Y.W., S.B., B.P., M.A., S.G., S.P.H.), and Covance Preclinical Services GmbH, Munster, Germany (B.K., L.B.)
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Dittrich M, Brauer C, Funari SS, Dobner B, Brezesinski G, Wölk C. Interactions of Cationic Lipids with DNA: A Structural Approach. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:14858-14868. [PMID: 30165742 DOI: 10.1021/acs.langmuir.8b01635] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Colloidal nucleic acid carrier systems based on cationic lipids are a promising pharmaceutical tool in the implementation of gene therapeutic strategies. This study demonstrates the complex behavior of DNA at the lipid-solvent interface facilitating structural changes of the lyotropic liquid-crystalline phases. For this study, the structural properties of six malonic acid based cationic lipids were determined using small- and wide-angle X-ray scattering (SAXS and WAXS) as well as differential scanning calorimetry (DSC). Selected lipids (lipid 3 and lipid 6) with high nucleic acid transfer activity have been investigated in detail because of the strong influence of the zwitterionic helper lipid 1,2-di(9 Z-octadecenoyl)- sn-glycero-3-phosphoethanolamine (DOPE) on the structural properties as well as of the complex formation of lipid-DNA complexes (lipoplexes). In the case of lipid 3, DNA stabilizes a metastable cubic mesophase with Im3 m symmetry and an Im3 m Qαc lipoplex is formed, which is rarely described for DNA lipoplexes in literature. In the case of lipid 6, a cubic mesophase with Im3 m symmetry turns into a fluid lamellar phase while mixing with DOPE and complexing DNA.
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Affiliation(s)
- Matthias Dittrich
- Max Planck Institute of Colloids and Interfaces , Science Park Potsdam-Golm, Am Mühlenberg 1 , 14476 Potsdam , Germany
| | - Chris Brauer
- Max Planck Institute of Colloids and Interfaces , Science Park Potsdam-Golm, Am Mühlenberg 1 , 14476 Potsdam , Germany
| | - Sergio S Funari
- Photon Science - DESY , Notkestrasse 85 , 22607 Hamburg , Germany
| | - Bodo Dobner
- Institute of Pharmacy, Research Group Biochemical Pharmacy , Martin-Luther-University , Wolfgang-Langenbeck-Strasse 4 , 06120 Halle (Saale) , Germany
| | - Gerald Brezesinski
- Max Planck Institute of Colloids and Interfaces , Science Park Potsdam-Golm, Am Mühlenberg 1 , 14476 Potsdam , Germany
| | - Christian Wölk
- Institute of Pharmacy, Research Group Biochemical Pharmacy , Martin-Luther-University , Wolfgang-Langenbeck-Strasse 4 , 06120 Halle (Saale) , Germany
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Abstract
For several decades extensive research has been conducted into the development of fusogenic lipid nanoparticles (LNPs) capable of introducing large, charged molecules into the cytoplasm of target cells. The majority of this work has focused on cationic LNPs encapsulating nucleic acids ranging from small oligonucleotides to large plasmid constructs thousands of bases long. However, since the introduction of siRNA payloads this quest for a non-viral, intracellular delivery systems has advanced significantly. Of particular importance was the demonstration that LNPs containing ionizable, dialkylamino lipids, enable potent hepatic gene silencing across species including humans. This review focuses on the evolution of this delivery system, summarizes the promising data now emerging from clinical trials and considers future directions for the platform.
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Pajuste K, Hyvönen Z, Petrichenko O, Kaldre D, Rucins M, Cekavicus B, Ose V, Skrivele B, Gosteva M, Morin-Picardat E, Plotniece M, Sobolev A, Duburs G, Ruponen M, Plotniece A. Gene delivery agents possessing antiradical activity: self-assembling cationic amphiphilic 1,4-dihydropyridine derivatives. NEW J CHEM 2013. [DOI: 10.1039/c3nj00272a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Dittrich M, Heinze M, Wölk C, Funari SS, Dobner B, Möhwald H, Brezesinski G. Structure-Function Relationships of New Lipids Designed for DNA Transfection. Chemphyschem 2011; 12:2328-37. [DOI: 10.1002/cphc.201100065] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 04/29/2011] [Indexed: 11/12/2022]
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Wölk C, Heinze M, Kreideweiß P, Dittrich M, Brezesinski G, Langner A, Dobner B. Synthesis and DNA transfection properties of new head group modified malonic acid diamides. Int J Pharm 2011; 409:46-56. [DOI: 10.1016/j.ijpharm.2011.02.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 02/14/2011] [Accepted: 02/17/2011] [Indexed: 12/19/2022]
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Abstract
IMPORTANCE OF THE FIELD Cancer is frequently caused by altered protein expression. Oligonucleotides (ONs) are short synthetic nucleic acid fragments, able to selectively correct protein expression into cells by different mechanisms. However, biological barriers hamper the therapeutic use of ONs without suitable delivery strategies. AREAS COVERED IN THIS REVIEW This review summarizes the most meaningful non-viral strategies for ON delivery, including the chemical modifications of the ON backbone and non-viral delivery systems. WHAT THE READER WILL GAIN The reader will gain an update of the main strategies for ON delivery in cancer. Advantages and limits of each approach are underlined. Emphasis is given to the delivery strategies that contributed to bringing ONs into clinical trials. TAKE HOME MESSAGE In the long story of ONs for cancer therapy, the development of delivery strategies has led, in the last few years, to different opportunities to use the high therapeutic potential of these molecules in humans.
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Affiliation(s)
- Giuseppe De Rosa
- University of Naples Federico II, Department of Pharmaceutical and Toxicological Chemistry, Faculty of Pharmacy, Via D Montesano n 49, Naples, Italy.
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Abstract
Current non-small cell lung cancer (NSCLC) chemotherapy and radiotherapy regimens, although showing definite survival benefit, still leave patients with a disappointing 15% 5-year overall survival rate. Because of the need to improve traditional outcomes, research has focused on identifying specific tumorigenic pathways that may serve as therapeutic targets. The most successful strategies to date are those aimed at the epidermal growth factor receptor (EGFR), which is found to be upregulated in 40%-80% of NSCLC. Several tyrosine kinase inhibitors and monoclonal antibodies (mAbs) have been developed that inhibit the EGFR receptor and have demonstrated clinical benefit in trials as single agents and in combination regimens. Here we discuss one such agent, the mAb nimotuzumab, the background of its development, its clinical experience in NSCLC thus far, and the rationale for expanding its use to other NSCLC treatment settings.
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Affiliation(s)
- William Boland
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
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10
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Nano and microtechnologies for the delivery of oligonucleotides with gene silencing properties. Molecules 2009; 14:2801-23. [PMID: 19701125 PMCID: PMC6255434 DOI: 10.3390/molecules14082801] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 07/22/2009] [Accepted: 07/27/2009] [Indexed: 01/13/2023] Open
Abstract
Oligonucleotides (ONs) are synthetic fragments of nucleic acid designed to modulate the expression of target proteins. DNA-based ONs (antisense, antigene, aptamer or decoy) and more recently a new class of RNA-based ONs, the small interfering RNAs (siRNAs), have gained great attention for the treatment of different disease states, such as viral infections, inflammation, diabetes, and cancer. However, the development of therapeutic strategies based on ONs is hampered by their low bioavailability, poor intracellular uptake and rapid degradation in biological fluids. The use of a non-viral carrier can be a powerful tool to overcome these drawbacks. Lipid or polymer-based nanotechnologies can improve biological stability and cellular uptake of ONs, with possibility of tissue and/or cellular targeting. The use of polymeric devices can also produce a prolonged release of the ON, thus reducing the need of frequent administrations. This review summarizes advantages and issues related to the main non-viral vectors used for ON delivery.
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Writer M, Hurley CA, Sarkar S, Copeman DM, Wong JB, Odlyha M, Jayne Lawrence M, Tabor AB, McAnulty RJ, Ayazi Shamlou P, Hailes HC, Hart SL. Analysis and optimization of the cationic lipid component of a lipid/peptide vector formulation for enhanced transfection in vitro and in vivo. J Liposome Res 2007; 16:373-89. [PMID: 17162579 DOI: 10.1080/08982100600992500] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
We have previously described a lipopolyplex formulation comprising a mixture of a cationic peptide with an integrin-targeting motif (K16GACRRETAWACG) and Lipofectin, a liposome consisting of DOTMA and DOPE in a 1:1 ratio. The high transfection efficiency of the mixture involved a synergistic interaction between the lipid/peptide components. The aim of this study was to substitute the lipid component of the lipopolyplex to optimize transfection further and to seek information on the structure-activity relationship of the lipids in the lipopolyplex. Symmetrical cationic lipids with diether linkages that varied in alkyl chain length were formulated into liposomes and then incorporated into a lipopolyplex by mixing with an integrin-targeting peptide and plasmid DNA. Luciferase transfections were performed of airway epithelial cells and fibroblasts in vitro and murine lung airways in vivo. The biophysical properties of lipid structures and liposome formulations and their potential effects on bilayer membrane fluidity were determined by differential scanning calorimetry and calcein-release assays. Shortening the alkyl tail from C18 to C16 or C14 enhanced lipopolyplex and lipoplex transfection in vitro but with differing effects. The addition of DOPE enhanced transfection when formulated into liposomes with saturated lipids but was more variable in its effects with unsaturated lipids. A substantial improvement in transfection efficacy was seen in murine lung transfection with unsaturated lipids with 16 carbon alkyl tails. The optimal liposome components of lipopolyplex and lipoplex vary and represent a likely compromise between their differing structural and functional requirements for complex formation and endosomal membrane destabilization.
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Affiliation(s)
- Michele Writer
- Wolfson Centre for Gene Therapy of Childhood Disease, UCL Institute of Child Health, London, UK
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13
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Mahato RI, Cheng K, Guntaka RV. Modulation of gene expression by antisense and antigene oligodeoxynucleotides and small interfering RNA. Expert Opin Drug Deliv 2006; 2:3-28. [PMID: 16296732 DOI: 10.1517/17425247.2.1.3] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Antisense oligodeoxynucleotides, triplex-forming oligodeoxynucleotides and double-stranded small interfering RNAs have great potential for the treatment of many severe and debilitating diseases. Concerted efforts from both industry and academia have made significant progress in turning these nucleic acid drugs into therapeutics, and there is already one FDA-approved antisense drug in the clinic. Despite the success of one product and several other ongoing clinical trials, challenges still exist in their stability, cellular uptake, disposition, site-specific delivery and therapeutic efficacy. The principles, strategies and delivery consideration of these nucleic acids are reviewed. Furthermore, the ways to overcome the biological barriers are also discussed so that therapeutic concentrations at their target sites can be maintained for a desired period.
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MESH Headings
- Animals
- DNA/chemistry
- DNA/genetics
- DNA/metabolism
- Drug Carriers
- Gene Expression Regulation
- Gene Silencing
- Gene Targeting/methods
- Genetic Therapy/methods
- Humans
- Nucleic Acid Conformation/drug effects
- Oligonucleotides, Antisense/chemistry
- Oligonucleotides, Antisense/genetics
- Oligonucleotides, Antisense/metabolism
- Oligonucleotides, Antisense/pharmacology
- Protein Biosynthesis/drug effects
- RNA Interference
- RNA Splicing/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Small Interfering/chemistry
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Transcription, Genetic/drug effects
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Affiliation(s)
- Ram I Mahato
- University of Tennessee Health Science Center, Department of Pharmaceutical Sciences, 26 South Dunlap Street, Feurt Bldg RM 406, Memphis, TN 38163, USA.
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Aukunuru JV, Ayalasomayajula SP, Kompella UB. Nanoparticle formulation enhances the delivery and activity of a vascular endothelial growth factor antisense oligonucleotide in human retinal pigment epithelial cells. J Pharm Pharmacol 2006; 55:1199-206. [PMID: 14604462 DOI: 10.1211/0022357021701] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The objective of this study was to investigate the delivery and activity of a vascular endothelial growth factor (VEGF) antisense oligonucleotide in a human retinal pigment epithelial cell line (ARPE-19) using a biodegradable nanoparticulate delivery system. A 19-mer antisense phosphorothioate oligonucleotide (PS-ODN) complementary to bases 6-24 relative to the translational start site of the VEGF mRNA, a sense PS-ODN and a mismatch PS-ODN were examined for the inhibition of secretion and mRNA expression of VEGF using an enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction, respectively. Nanoparticles of the antisense oligonucleotides were formulated using a poly(lactide-co-glycolide) (50:50) copolymer using a double emulsion solvent evaporation method. After preparing nanoparticles, drug loading, encapsulation efficiency and particle size were determined. The cells were exposed to either plain solution of oligonucleotide or nanoparticles of oligonucleotide from Day 3 through Day 6. Alternatively, the cells were incubated with PS-ODNs and lipofectin for 4 h on Day 4. In all studies, VEGF secretion and mRNA expression were determined on Day 6. The particle size, drug loading and encapsulation efficiency were 252 nm, 5.5% and 16.5%, respectively. The antisense PS-ODN inhibited VEGF mRNA and protein secretion when delivered using nanoparticles or lipofectin but not in its free form. This was consistent with the ability of nanoparticles and lipofectin to elevate the cellular uptake of the oligonucleotide by 4-fold and 13-fold, respectively. Neither mismatch nor sense oligonucleotides inhibited VEGF secretion. In conclusion, biodegradable nanoparticles enhance cellular delivery of a VEGF antisense oligonucleotide and inhibit VEGF secretion and mRNA expression in a human retinal pigment epithelial cell line.
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Affiliation(s)
- Jithan V Aukunuru
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, 68198-6025, USA
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Lindner LH, Brock R, Arndt-Jovin D, Eibl H. Structural variation of cationic lipids: minimum requirement for improved oligonucleotide delivery into cells. J Control Release 2005; 110:444-456. [PMID: 16297484 DOI: 10.1016/j.jconrel.2005.10.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 10/11/2005] [Accepted: 10/13/2005] [Indexed: 01/13/2023]
Abstract
In vivo transfection efficiency (TE) using cationic liposome/oligonucleotide (ODN) complexes is often hampered by interactions with serum components. Novel cationic lipids with different hydroxyethyl or dihydroxypropyl ammonium backbones, esterified hydrocarbon chains and hydroxy substituents have been synthesized and applied in cationic liposome formulations with and without the helper lipid DOPE (1:1, m/m). Their properties for cellular ODN delivery were determined using fluorescently labeled ODNs (F-ODNs). Cationic lipids with hydrocarbon chains esterified to non-glycerol backbones in non-vicinal configuration were completely ineffective in nuclear ODN-delivery. Instead, an increased cytoplasmic localization of F-ODNs was observed. Cationic lipids equipped with only one hydrocarbon were completely incompetent for cellular ODN delivery. In the absence of serum, all cationic lipids tested with hydrocarbon chains in vicinal configuration esterified to a glycerol backbone (the respective N-(1,2-diacyl-dihydroxypropyl)-N,N,N-trimethyl-ammoniumchlorides or N-(1,2-diacyl-dihydroxypropyl)-N(hydroxyethyl)-N,N-dimethyl-ammoniumchlorides as well as N-(1,2-diacyl-dihydroxypropyl)-N(1,2-dihydroxypropyl)-N,N-dimethyl-ammoniumchlorides with lauroyl, myristoyl, palmitoyl, stearoyl and erucoyl chains) were able to transfect cells when combined with DOPE (20-80% nuclear fluorescence). Remarkably, only the analog esterified with two myristoyl chains was equally effective even in the absence of DOPE. By adding hydroxy groups to the N-alkyl residue, TE under serum conditions was improved yielding transfection rates of 55%, 75% and 90% for 0, 1 or 2 substituted hydroxy groups, respectively. For plasmid DNA, different requirements were identified. Again, the analog with two myristoyl chains was most effective but only in the presence of DOPE. However, the addition of hydroxy groups had no influence on the TE in the presence of serum.
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Affiliation(s)
- Lars H Lindner
- Max Planck Institute for Biophysical Chemistry, Phospholipid Research Group, Goettingen, Germany.
| | - Roland Brock
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Goettingen, Germany
| | - Donna Arndt-Jovin
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Goettingen, Germany
| | - Hansjoerg Eibl
- Max Planck Institute for Biophysical Chemistry, Phospholipid Research Group, Goettingen, Germany
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Kahan BD, Stepkowski S, Kilic M, Katz SM, Van Buren CT, Welsh MS, Tami JA, Shanahan WR. Phase I and phase II safety and efficacy trial of intercellular adhesion molecule-1 antisense oligodeoxynucleotide (ISIS 2302) for the prevention of acute allograft rejection. Transplantation 2004; 78:858-63. [PMID: 15385805 DOI: 10.1097/01.tp.0000128857.77893.d2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND ISIS 2302, an antisense oligonucleotide that inhibits the expression of human intercellular adhesion molecule (ICAM)-1, was evaluated in combination with a cyclosporine (CsA)-prednisone (Pred) regimen first in a phase I safety and pharmacokinetic study and then in a phase II assessment of prophylaxis of acute rejection episodes in deceased donor renal allografts. METHODS Both phase I and phase II trials were double-blinded and placebo-controlled, including 17 stable and 39 de novo patients, respectively, in time-lagged, ascending-dose regimens. Each study compared the outcomes of 8 alternate-day intravenous infusions of four ISIS 2302 dose levels (0.05, 0.5, 1.0, or 2.0 mg/kg) versus placebo (3:1 ratio). Patients were followed for 34 days (phase I) or 6 months (phase II). All transplant patients were followed for 3 years. RESULTS ISIS 2302 produced no evident toxicity; a significant, dose-related increase in activated partial thromboplastin time was accompanied by a trend toward a decreased platelet count. ISIS 2302 did not alter the pharmacokinetic behavior of CsA. At 6 months, the rates of acute rejection episodes were 38.1% in the ISIS 2302 group versus 20.0% in the placebo group. Three-year graft survivals were similar. The mean creatinine values at 1, 2, and 3 years for all ISIS dose groups combined versus placebo over 3 years showed no significant differences. CONCLUSIONS ISIS 2302 did not evoke side-effects and produced slightly improved renal function. However, in this pilot study, it did not further reduce the rate of acute rejection episodes or increase graft survival compared to a concentration-controlled CsA-Pred regimen.
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Affiliation(s)
- Barry D Kahan
- Division of Immunology and Organ Transplantation, Department of Surgery, The University of Texas Medical School at Houston, Houston, TX 77030, USA.
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Jääskeläinen I, Lappalainen K, Honkakoski P, Urtti A. Requirements for delivery of active antisense oligonucleotides into cells with lipid carriers. Methods Enzymol 2004; 387:210-30. [PMID: 15172166 DOI: 10.1016/s0076-6879(04)87013-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
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18
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Wiethoff CM, Koe JG, Koe GS, Middaugh CR. Compositional effects of cationic lipid/DNA delivery systems on transgene expression in cell culture. J Pharm Sci 2004; 93:108-23. [PMID: 14648641 DOI: 10.1002/jps.10519] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Studies of the contribution of various physical properties of cationic lipid/DNA complexes (CLDCs) to their observed transgene expression in vitro were conducted using cationic liposomes composed of the cationic lipids 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) and dimethyldioctadecylammonium bromide (DDAB), with or without equimolar amounts of cholesterol (CHOL) or 1,2-dioleoylphosphatidylethanolamine (DOPE). The relative degree of luciferase expression by CLDCs is dependent on a complex relationship between net charge of the CLDC as well as previously reported properties, such as membrane fluidity and curvature of the cationic bilayer. Assessments were made of the role of these physical properties on CLDC stability in the extracellular medium, the extent of DNA cellular association, and membrane disruption activity. The efficiency of luciferase expression from negatively charged CLDCs is greatly improved by incorporation of DOPE. This result correlates with enhanced resistance to inhibition of gene delivery by heparan sulfate, increased cellular association of DNA, and enhanced membrane disruption activity. Luciferase expression by positively charged CLDCs is greatly reduced by incorporating equimolar amounts of CHOL and DOPE. This result occurs is in spite of increased resistance to heparan sulfate-mediated inhibition of gene delivery, increased DNA cellular association, and enhanced membrane disruption activity. The observed CLDC compositional effects on luciferase expression along with observed effects on the delivery process suggest that a better understanding of the kinetics and specific routes of gene delivery is necessary.
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Affiliation(s)
- Christopher M Wiethoff
- Department of Pharmaceutical Chemistry, The University of Kansas, 2095 Constant Avenue, Lawrence, Kansas 66047, USA
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Das AR, Dattagupta N, Sridhar CN, Wu WK. A novel thiocationic liposomal formulation of antisense oligonucleotides with activity against Mycobacterium tuberculosis. SCANDINAVIAN JOURNAL OF INFECTIOUS DISEASES 2003; 35:168-74. [PMID: 12751711 DOI: 10.1080/00365540310000102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This study describes the development of a novel thiocationic (OBEHYTOP) lipid-based formulation of phosphorothioate antisense oligonucleotides (PAOs) showing inhibitory activity against mycobacterium tuberculosis (mTB) as measured by an in vitro BACTEC 460TB assay. PAOs were designed based on sequences complementary to essential regions of the mycobacterial genome from published nucleic acid databases in GenBank. These included the superoxide dismutase sod A gene (TBS3), catalase-peroxidase katG gene (TBK1, TBK10), RNA polymerase beta-subunit rpo B gene (TBR5) and diaminopimelate decarboxylase lys A gene (TBL5). The effect of PAOs (TBS3, K1, K10, R5 and L5) alone on mTB was not significant compared with the no-drug control over a period of exposure of 150 h (ranges of -11.8 to +23.58% at 72 h; 15.26 to +25.82% at 96 h and -5.51 to +24.00% at 150 h). Liposomal formulations (10:5:2 OBEHYTOP:oleic acid:vitamin D3) of PAOs resulted in statistically significant (p < 0.05 in all cases) inhibition (ranges of -51.45 to -63.00% at 72 h; -56.75 to -67.96% at 96 h; -51.45 to -60.26% at 150 h) compared with PAOs alone, thiocationic liposomal control and liposomal components. Positive controls of streptomycin and isoniazid used at their minimum inhibitory concentrations of 2.00 and 0.10 microM, respectively, resulted in average % inhibition values of -94% and -97.36%, respectively, indicating that these thiocationic lipid-formulated PAOs showed inhibitory activity directed against mTB in vitro.
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Affiliation(s)
- Aditya R Das
- Inhale Therapeutic Systems, San Carlos, California 94070, USA.
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20
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Zuhorn IS, Oberle V, Visser WH, Engberts JBFN, Bakowsky U, Polushkin E, Hoekstra D. Phase behavior of cationic amphiphiles and their mixtures with helper lipid influences lipoplex shape, DNA translocation, and transfection efficiency. Biophys J 2002; 83:2096-108. [PMID: 12324427 PMCID: PMC1302298 DOI: 10.1016/s0006-3495(02)73970-2] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Cationic lipids are widely used for gene transfection, but their mechanism of action is still poorly understood. To improve this knowledge, a structure-function study was carried out with two pyridinium-based lipid analogs with identical headgroups but differing in alkyl chain (un)saturation, i.e., SAINT-2 (diC18:1) and SAINT-5 (diC18:0). Although both amphiphiles display transfection activity per se, DOPE strongly promotes SAINT-2-mediated transfection, but not that of SAINT-5, despite the fact that DOPE effectively facilitates plasmid dissociation from either lipoplex. This difference appears to correlate with membrane stiffness, dictated by the cationic lipid packing in the donor liposomes, which governs the kinetics of lipid recruitment by the plasmid upon lipoplex assembly. Because of its interaction with the relatively rigid SAINT-5 membranes, the plasmid becomes inappropriately condensed, which results in formation of structurally deformed lipoplexes. This structural deformation does not affect its cellular uptake but, rather, hampers plasmid translocation across endosomal and/or nuclear membranes. This is inferred from the observation that both lipoplexes effectively translocate much smaller oligonucleotides into cells. In fact, SAINT-5/DOPE-mediated transfection is greatly improved when, before lipoplex assembly, the plasmid is stabilized by condensation with polylysine. The results emphasize a role of the structural shape of the plasmid in gaining cytosolic/nuclear access. Moreover, it has been proposed that such a translocation is promoted when the lipoplex adopts the hexagonal phase, and data are presented that demonstrate that the lamellar SAINT-5/DOPE lipoplex adopts such a phase after its interaction with acidic phospholipid-containing membranes.
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Affiliation(s)
- Inge S Zuhorn
- Department of Membrane Cell Biology, University of Groningen, The Netherlands
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21
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Ferrari ME, Rusalov D, Enas J, Wheeler CJ. Synergy between cationic lipid and co-lipid determines the macroscopic structure and transfection activity of lipoplexes. Nucleic Acids Res 2002; 30:1808-16. [PMID: 11937635 PMCID: PMC113211 DOI: 10.1093/nar/30.8.1808] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The large number of cytofectin and co-lipid combinations currently used for lipoplex-mediated gene delivery reflects the fact that the optimal cytofectin/co-lipid combination varies with the application. The effects of structural changes in both cytofectin and co-lipid were systematically examined to identify structure-activity relationships. Specifically, alkyl chain length, degree of unsaturation and the head group to which the alkyl side chain was attached were examined to determine their effect on lipoplex structure and biological activity. The macroscopic lipoplex structure was assessed using a dye-binding assay and the biological activity was examined using in vitro transfection in three diverse cell lines. Lipoplexes were formulated in three different vehicles currently in use for in vivo delivery of naked plasmid DNA (pDNA) and lipoplex formulations. The changes in dye accessibility were consistent with structural changes in the lipoplex, which correlated with alterations in the formulation. In contrast, transfection activity of different lipoplexes was cell type and vehicle dependent and did not correlate with dye accessibility. Overall, the results show a correlation between transfection and enhanced membrane fluidity in both the lipoplex and cellular membranes.
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Affiliation(s)
- Marilyn E Ferrari
- Department of Chemistry, Vical Incorporated, 9373 Towne Centre Drive, San Diego, CA 92121, USA
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22
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Sen L, Hong YS, Luo H, Cui G, Laks H. Efficiency, efficacy, and adverse effects of adenovirus vs. liposome-mediated gene therapy in cardiac allografts. Am J Physiol Heart Circ Physiol 2001; 281:H1433-41. [PMID: 11514316 DOI: 10.1152/ajpheart.2001.281.3.h1433] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Virus- and nonvirus-mediated immunosuppressive cytokine gene therapy prolongs cardiac allograft survival in various nonfunctional heart transplant animal models, but its cardiac adverse effects have not been addressed. Recently, we developed a functional heterotopic heart transplant model in rabbits. For the first time, we were able to systematically compare the efficiency, efficacy, and adverse effects of optimized adenovirus- and liposome-mediated ex vivo interleukin (IL)-10 gene transfer in functional donor hearts. The efficiency of liposome-mediated gene transfer was greatly improved in physiologically functioning donor hearts and was only three- to fourfold lower than adenovirus-mediated gene transfer. The efficacy of liposome-mediated IL-10 gene transfer was much higher than that mediated by adenovirus. Significant negative inotropic and arrhythmogenic adverse effects on transplanted hearts were observed due to viral cytotoxicity and immunogenesis, which greatly abated the therapeutic efficacy of this first generation adenovirus-mediated gene therapy.
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Affiliation(s)
- L Sen
- Division of Cardiothoracic Surgery, Department of Surgery, University of California Medical Center and University of California School of Medicine, Los Angeles, California 90095, USA.
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23
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Berton M, Turelli P, Trono D, Stein CA, Allémann E, Gurny R. Inhibition of HIV-1 in cell culture by oligonucleotide-loaded nanoparticles. Pharm Res 2001; 18:1096-101. [PMID: 11587479 DOI: 10.1023/a:1010962507273] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
PURPOSE To investigate the potential use of polymeric nanoparticles for the delivery of antisense oligonucleotides in HIV-1-infected cell cultures. METHODS Phosphorothioate oligonucleotides were encapsulated into poly (D,L-lactic acid) nanoparticles. Two models of infected cells were used to test the ability of nanoparticles to deliver them. HeLa P4-2 CD4+ cells, stably transfected with the beta-galactosidase reporter gene, were first used to evaluate the activity of the oligonucleotides on a single-round infection cycle. The acutely infected lymphoid CEM cells were then used to evaluate the inhibition of the viral production of HIV-1 by the oligonucleotides. RESULTS The addition to infected CEM cells of nanoparticles containing gag antisense oligonucleotides in the nanomolar range led to strong inhibition of the viral production in a concentration-dependent manner. Similar results were previously observed in HeLa P4-2 CD4+ cells. Nanoparticle-entrapped random-order gag oligonucleotides had similar effects on reverse transcription. However, the reverse transcriptase activity of infected cells treated with nanomolar concentrations of free antisense and random oligonucleotides was not affected. CONCLUSIONS These results suggest that poly (D,L-lactic acid) nanoparticles may have great potential as an efficient delivery system for oligonucleotides in HIV natural target cells, i.e., lymphocytic cells.
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Affiliation(s)
- M Berton
- School of Pharmacy, University of Geneva, Switzerland.
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24
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Baker BF, Condon TP, Koller E, McKay RA, Siwkowski AM, Vickers TA, Monia BP. Discovery and analysis of antisense oligonucleotide activity in cell culture. Methods 2001; 23:191-8. [PMID: 11181038 DOI: 10.1006/meth.2000.1120] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the past decade antisense oligonucleotides (ASOs) have proven to be a useful tool for dissection of gene function in molecular cell biology (Koller, E., Gaarde, W. A., and Monia, B. P. (2000) Trends Pharm. Sci., 21, 142-148), and validation of gene targets in animal models (Crooke, S. T. (1998) Biotechnol. Gen. Eng. Rev. 15, 121-157), as well as a means for therapeutic treatment of human diseases (Bennett, C. F. (1999) Exp. Opin. Invest. Drugs 8, 237-253). An important step toward usage of ASOs in the described applications is identification of an active ASO. This article describes the underlying basis and means for achieving this goal in cell culture.
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Affiliation(s)
- B F Baker
- Isis Pharmaceuticals, Inc., 2292 Faraday Avenue, Carlsbad, California 92008, USA.
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25
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Hyvönen Z, Plotniece A, Reine I, Chekavichus B, Duburs G, Urtti A. Novel cationic amphiphilic 1,4-dihydropyridine derivatives for DNA delivery. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1509:451-66. [PMID: 11118554 DOI: 10.1016/s0005-2736(00)00327-8] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In order to find new efficient and safe agents for gene delivery, we have designed and synthesized nine novel single- and double-charged amphiphiles on the base of 1,4-dihydropyridine (1,4-DHP) ring. Some biophysical properties of the amphiphilic dihydropyridines and their complexes with DNA were examined. We investigated the transfer of beta-galactosidase gene into fibroblasts (CV1-P) and retinal pigment epithelial (D 4O7) cell lines in vitro. The structure-property relationships of the compounds were investigated in various ways. The net surface charges of 1,4-DHP liposomes were highly positive (25-49 mV). The double-charged compounds condensed DNA more efficiently than single-charged and the condensation increases with the increasing +/- charge ratio between the carrier and DNA. Double-charged compounds showed also buffering properties at endosomal pH and these compounds were more efficient in transfecting the cells, but transfection efficiency of amphiphiles was cell type-dependent. The length of alkyl chains in double-charged compounds affected the transfection efficacy. The most active amphiphile (compound VI) was double-charged and had two C(12) alkyl chains. At optimal charge ratio (+/- 4), it was 2.5 times more effective than PEI 25 and 10 times better than DOTAP, known efficient polymeric and liposomal transfection agents. Formulation of amphiphiles with DOPE did not change their activities. Our data demonstrate some important effects of amphiphile structure on biophysics and activity. The data also suggest that cationic amphiphilic 1,4-DHP derivatives may find use as DNA delivery system.
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Affiliation(s)
- Z Hyvönen
- Department of Pharmaceutics, University of Kuopio, Finland
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26
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Mui B, Ahkong QF, Chow L, Hope MJ. Membrane perturbation and the mechanism of lipid-mediated transfer of DNA into cells. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1467:281-92. [PMID: 11030588 DOI: 10.1016/s0005-2736(00)00226-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Mixtures of cationic lipids and unsaturated phosphatidylethanolamine are used extensively for the intracellular delivery of plasmids and antisense oligodeoxynucleotides (ODN) in vitro. However, the mechanism by which cytoplasmic delivery of these large molecules is achieved remains unclear. The common hypothesis is that phosphatidylethanolamine promotes fusion of lipid/DNA particles with endosomal membranes, but this is inconsistent with several reports that have failed to correlate the fusogenic activity of a wide variety of lipid/DNA particles, measured by lipid mixing techniques, with their transfection activity. To address this issue further we have conducted a detailed analysis of the lipid mixing and DNA transfer activity of two, physically similar but functionally different, lipid/DNA particles composed of equimolar dioleyldimethylammonium chloride (DODAC) and dioleoylphosphatidylethanolamine (DOPE) or dioleoylphosphatidylcholine (DOPC). In combination with DODAC both phospholipids form almost identical lipid/DNA particles, they are endocytosed by cells to the same extent and each undergoes equivalent lipid mixing with cell membranes after uptake. Despite this, DNA transfer is 10- to 100-fold more extensive for lipid/DNA particles containing DOPE. We conclude that lipid mixing between lipid-based delivery systems and endosomal membranes must occur for DNA transfer to occur. However, the potency of different lipid/DNA particles correlates better with the ability of the exogenous lipid to disrupt membrane integrity.
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Affiliation(s)
- B Mui
- Inex Pharmaceutials Corp, Burnaby, BC, Canada.
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27
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Garcia-Chaumont C, Seksek O, Grzybowska J, Borowski E, Bolard J. Delivery systems for antisense oligonucleotides. Pharmacol Ther 2000; 87:255-77. [PMID: 11008003 DOI: 10.1016/s0163-7258(00)00062-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
In vitro, the efficacy of the antisense approach is strongly increased by systems delivering oligodeoxyribonucleotides (ODNs) to cells. Up to now, most of the developed vectors favor ODN entrance by a mechanism based on endocytosis. Such is the case for particulate systems, including liposomes (cationic or non-cationic), cationic polyelectrolytes, and delivery systems targeted to specific receptors. Under these conditions, endosomal compartments may represent a dead end for ODNs. Current research attempts to develop conditions for escaping from these compartments. A new class of vectors acts by passive permeabilization of the plasma membrane. It includes peptides, streptolysin O, and cationic derivatives of polyene antibiotics. In vivo, the interest of a delivery system, up to now, has appeared limited. Development of vectors insensitive to the presence of serum seems to be a prerequisite for future improvements.
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Affiliation(s)
- C Garcia-Chaumont
- LPBC, CNRS ESA 7033, Université Pierre et Marie Curie, case 138, 4, place Jussieu, 75252 05, Paris cedex, France
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28
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Berton M, Allémann E, Stein CA, Gurny R. Highly loaded nanoparticulate carrier using an hydrophobic antisense oligonucleotide complex. Eur J Pharm Sci 1999; 9:163-70. [PMID: 10620729 DOI: 10.1016/s0928-0987(99)00049-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Antisense oligonucleotides, and particularly those with phosphorothioate backbones, have emerged as potential gene specific therapeutic agents and are currently undergoing evaluation in clinical trials for a variety of diseases. In the area of HIV-1 therapeutics, targeting of oligonucleotides to infected cells, such as macrophages, would be highly desirable. The present study was designed to prepare and characterize oligonucleotide-loaded nanoparticles for this purpose. Due to their hydrophilic characteristics, oligonucleotides are difficult to entrap in polymeric particles. Here, the oligonucleotides were first complexed with cetyltrimethylammonium bromide. The oligonucleotide-loaded nanoparticles were prepared by the emulsification-diffusion method and subsequently purified. In comparison with previous studies, a high oligonucleotide-loading was achieved; 2.5, 5 and 10% oligonucleotide loading were assessed. If the initial oligonucleotide content was 4%, this method produced a final oligonucleotide loading of 1.9% with an entrapment efficiency of 47%. The integrity of the oligonucleotide and of the polymer, in the final freeze-dried product, was retained.
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Affiliation(s)
- M Berton
- School of Pharmacy, University of Geneva, quai E.-Ansermet CH-1211, Geneva, Switzerland
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29
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Wasan EK, Harvie P, Edwards K, Karlsson G, Bally MB. A multi-step lipid mixing assay to model structural changes in cationic lipoplexes used for in vitro transfection. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1461:27-46. [PMID: 10556486 DOI: 10.1016/s0005-2736(99)00144-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Formation of liposome/polynucleotide complexes (lipoplexes) involves electrostatic interactions, which induce changes in liposome structure. The ability of these complexes to transfer DNA into cells is dependent on the physicochemical attributes of the complexes, therefore characterization of binding-induced changes in liposomes is critical for the development of lipid-based DNA delivery systems. To clarify the apparent lack of correlation between membrane fusion and in vitro transfection previously observed, we performed a multi-step lipid mixing assay to model the sequential steps involved in transfection. The roles of anion charge density, charge ratio and presence of salt on lipid mixing and liposome aggregation were investigated. The resonance-energy transfer method was used to monitor lipid mixing as cationic liposomes (DODAC/DOPE and DODAC/DOPC; 1:1 mole ratio) were combined with plasmid, oligonucleotides or Na(2)HPO(4). Cryo-transmission electron microscopy was performed to assess morphology. As plasmid or oligonucleotide concentration increased, lipid mixing and aggregation increased, but with Na(2)HPO(4) only aggregation occurred. NaCl (150 mM) reduced the extent of lipid mixing. Transfection studies suggest that the presence of salt during complexation had minimal effects on in vitro transfection. These data give new information about the effects of polynucleotide binding to cationic liposomes, illustrating the complicated nature of anion induced changes in liposome morphology and membrane behavior.
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Affiliation(s)
- E K Wasan
- Advanced Therapeutics-Medical Oncology, BC Cancer Agency, 600 West 10th Ave., Vancouver, BC, Canada
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