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Cellular uptake and intracellular trafficking of oligonucleotides. Adv Drug Deliv Rev 2015; 87:35-45. [PMID: 25881722 DOI: 10.1016/j.addr.2015.04.005] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 02/10/2015] [Accepted: 04/07/2015] [Indexed: 02/07/2023]
Abstract
Oligonucleotides manifest much promise as potential therapeutic agents. However, understanding of how oligonucleotides function within living organisms is still rather limited. A major concern in this regard is the mechanisms of cellular uptake and intracellular trafficking of both 'free' oligonucleotides and oligonucleotides associated with various polymeric or nanocarrier delivery systems. Here we review basic aspects of the mechanisms of endocytosis and intracellular trafficking and how insights from these processes can be used to understand oligonucleotide delivery. In particular we discuss opportunities for escape of oligonucleotides from endomembrane compartments and describe recent studies using small molecules to enhance oligonucleotide effects.
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52
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Sequence-specific transport of oligonucleotides into human endothelial cells. Russ Chem Bull 2015. [DOI: 10.1007/s11172-015-1033-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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53
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Ramachandran R, Yaksh TL. Therapeutic use of botulinum toxin in migraine: mechanisms of action. Br J Pharmacol 2015; 171:4177-92. [PMID: 24819339 DOI: 10.1111/bph.12763] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 04/25/2014] [Accepted: 05/02/2014] [Indexed: 12/30/2022] Open
Abstract
Migraine pain represents sensations arising from the activation of trigeminal afferents, which innervate the meningeal vasculature and project to the trigeminal nucleus caudalis (TNC). Pain secondary to meningeal input is referred to extracranial regions innervated by somatic afferents that project to homologous regions in the TNC. Such viscerosomatic convergence accounts for referral of migraine pain arising from meningeal afferents to particular extracranial dermatomes. Botulinum toxins (BoNTs) delivered into extracranial dermatomes are effective in and approved for treating chronic migraine pain. Aside from their well-described effect upon motor endplates, BoNTs are also taken up in local afferent nerve terminals where they cleave soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, and prevent local terminal release. However, a local extracranial effect of BoNT cannot account for allthe effects of BoNT upon migraine. We now know that peripherally delivered BoNTs are taken up in sensory afferents and transported to cleave SNARE proteins in the ganglion and TNC, prevent evoked afferent release and downstream activation. Such effects upon somatic input (as from the face) likewise would not alone account for block of input from converging meningeal afferents. This current work suggests that BoNTs may undergo transcytosis to cleave SNAREs in second-order neurons or in adjacent afferent terminals. Finally, while SNAREs mediate exocytotic release, they are also involved in transport of channels and receptors involved in facilitated pain states. The role of such post-synaptic effects of BoNT action in migraine remains to be determined.
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Affiliation(s)
- Roshni Ramachandran
- Anesthesiology Research, Department of Anesthesiology, University of California, San Diego, La Jolla, CA, USA
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54
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Liang XH, Sun H, Shen W, Crooke ST. Identification and characterization of intracellular proteins that bind oligonucleotides with phosphorothioate linkages. Nucleic Acids Res 2015; 43:2927-45. [PMID: 25712094 PMCID: PMC4357732 DOI: 10.1093/nar/gkv143] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although the RNase H-dependent mechanism of inhibition of gene expression by chemically modified antisense oligonucleotides (ASOs) has been well characterized, little is known about the interactions between ASOs and intracellular proteins that may alter cellular localization and/or potency of ASOs. Here, we report the identification of 56 intracellular ASO-binding proteins using multi-step affinity selection approaches. Many of the tested proteins had no significant effect on ASO activity; however, some proteins, including La/SSB, NPM1, ANXA2, VARS and PC4, appeared to enhance ASO activities, likely through mechanisms related to subcellular distribution. VARS and ANXA2 co-localized with ASOs in endocytic organelles, and reduction in the level of VARS altered lysosome/ASO localization patterns, implying that these proteins may facilitate ASO release from the endocytic pathway. Depletion of La and NPM1 reduced nuclear ASO levels, suggesting potential roles in ASO nuclear accumulation. On the other hand, Ku70 and Ku80 proteins inhibited ASO activity, most likely by competition with RNase H1 for ASO/RNA duplex binding. Our results demonstrate that phosphorothioate-modified ASOs bind a set of cellular proteins that affect ASO activity via different mechanisms.
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Affiliation(s)
- Xue-hai Liang
- Department of Core Antisense Research, ISIS Pharmaceuticals, Carlsbad, CA 92010, USA
| | - Hong Sun
- Department of Core Antisense Research, ISIS Pharmaceuticals, Carlsbad, CA 92010, USA
| | - Wen Shen
- Department of Core Antisense Research, ISIS Pharmaceuticals, Carlsbad, CA 92010, USA
| | - Stanley T Crooke
- Department of Core Antisense Research, ISIS Pharmaceuticals, Carlsbad, CA 92010, USA
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55
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Lorenzer C, Dirin M, Winkler AM, Baumann V, Winkler J. Going beyond the liver: progress and challenges of targeted delivery of siRNA therapeutics. J Control Release 2015; 203:1-15. [PMID: 25660205 DOI: 10.1016/j.jconrel.2015.02.003] [Citation(s) in RCA: 205] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 01/29/2015] [Accepted: 02/02/2015] [Indexed: 12/25/2022]
Abstract
Therapeutic gene silencing promises significant progress in pharmacotherapy, including considerable expansion of the druggable target space and the possibility for treating orphan diseases. Technological hurdles have complicated the efficient use of therapeutic oligonucleotides, and siRNA agents suffer particularly from insufficient pharmacokinetic properties and poor cellular uptake. Intense development and evolution of delivery systems have resulted in efficient uptake predominantly in liver tissue, in which practically all nanoparticulate and liposomal delivery systems show the highest accumulation. The most efficacious strategies include liposomes and bioconjugations with N-acetylgalactosamine. Both are in early clinical evaluation stages for treatment of liver-associated diseases. Approaches for achieving knockdown in other tissues and tumors have been proven to be more complicated. Selective targeting to tumors may be enabled through careful modulation of physical properties, such as particle size, or by taking advantage of specific targeting ligands. Significant barriers stand between sufficient accumulation in other organs, including endothelial barriers, cellular membranes, and the endosome. The brain, which is shielded by the blood-brain barrier, is of particular interest to facilitate efficient oligonucleotide therapy of neurological diseases. Transcytosis of the blood-brain barrier through receptor-specific docking is investigated to increase accumulation in the central nervous system. In this review, the current clinical status of siRNA therapeutics is summarized, as well as innovative and promising preclinical concepts employing tissue- and tumor-targeted ligands. The requirements and the respective advantages and drawbacks of bioconjugates and ligand-decorated lipid or polymeric particles are discussed.
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Affiliation(s)
- Cornelia Lorenzer
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstraße 14, 1090 Vienna, Austria
| | - Mehrdad Dirin
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstraße 14, 1090 Vienna, Austria
| | - Anna-Maria Winkler
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstraße 14, 1090 Vienna, Austria
| | - Volker Baumann
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstraße 14, 1090 Vienna, Austria
| | - Johannes Winkler
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstraße 14, 1090 Vienna, Austria.
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56
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Nakagawa O. [Development of artificial nucleic acids functionalized for damaged gene diagnosis, gene inhibition and delivery system]. YAKUGAKU ZASSHI 2014; 134:1319-29. [PMID: 25452241 DOI: 10.1248/yakushi.14-00197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Artificial nucleic acids have recently been widely used with their properties optimized for various technologies such as the inhibition of gene expression (antisense/antigene strategies, RNA interference) and genetic diagnosis (single nucleotide polymorphism (SNP), damaged nucleobase). For practical application of nucleic acid therapeutics, establishment of an effective delivery system for oligonucleotides is also required because of their poor permeability into cells. Various useful delivery technologies including lipoplexes formed using cationic lipids and polyplexes made with cationic polymers have been developed; however, there is no crucial tool for oligonucleotide therapeutics at present. If technologies of functional nucleic acids and adequate delivery systems are cooperatively developed, the realization of nucleic acid therapeutics might be effectively accelerated. Based on this concept, we have been cooperatively developing these technologies based on organic synthetic chemistry during the past decade. This paper summarizes our recent results: 1) development of a specific fluorescent probe for 8-oxoguanine; 2) synthesis and evaluation of a prodrug-type small interfering RNA (siRNA) molecule; and 3) targeted intracellular delivery of oligonucleotides via conjugation with receptor-targeted ligands.
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Affiliation(s)
- Osamu Nakagawa
- Graduate School of Pharmaceutical Sciences, Osaka University
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57
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Metelev VG, Kubareva EA, Oretskaya TS. Regulation of activity of transcription factor NF-κB by synthetic oligonucleotides. BIOCHEMISTRY (MOSCOW) 2014; 78:867-78. [PMID: 24228874 DOI: 10.1134/s0006297913080026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Eukaryotic dimeric nuclear factor-κB (NF-κB) is one of the main transcription factors that activate expression of genes, products of which play the key role in development of cardiovascular pathologies, carcinogenesis, and inflammatory and viral diseases. In this review, the main attention is given to modulation of the transcription factor NF-κB activity by antisense oligonucleotides and oligonucleotide decoys. Also, current concepts about interactions between NF-κB dimers and DNA and general problems that arise in experimental use of synthetic oligonucleotides in vivo are discussed.
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Affiliation(s)
- V G Metelev
- Faculty of Chemistry, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninsky Gory 1, Moscow, 119991, Russia.
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58
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Nielsen C, Kjems J, Sørensen KR, Engelholm LH, Behrendt N. Advances in targeted delivery of small interfering RNA using simple bioconjugates. Expert Opin Drug Deliv 2014; 11:791-822. [PMID: 24669756 DOI: 10.1517/17425247.2014.896898] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Development of drugs based on RNA interference by small interfering RNA (siRNA) has been progressing slowly due to a number of challenges associated with the in vivo behavior of siRNA. A central problem is controlling siRNA delivery to specific cell types. Here, we review existing literature on one type of strategy for solving the issue of cell-specific delivery of siRNA, namely delivering the siRNA as part of simple bioconjugate constructs. AREAS COVERED This review presents current experience from strategies aimed at targeting siRNA to specific cell types, by associating the siRNA with a targeting moiety, in a simple bioconjugate construct. We discuss the use of different types of targeting moieties, as well as the different conjugation strategies employed for preparing these bioconjugate constructs that deliver the siRNA to target cells. We focus especially on the in-built or passive functionalities associated with each strategy, in order to identify key elements of successful siRNA delivery strategies with potential for further exploration. EXPERT OPINION By evaluating the current literature on this subject, we identify strategies and concepts that are suitable for future studies, to enable the development of highly efficient simple bioconjugates for targeted siRNA delivery with therapeutic application.
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Affiliation(s)
- Christoffer Nielsen
- University of Copenhagen, Copenhagen University Hospital and Biotech Research and Innovation Centre (BRIC), Copenhagen Biocenter, Finsen Laboratory , Ole Maaloes Vej 5, DK-2200 Copenhagen N , Denmark +45 35 45 60 33 ;
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59
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Multicellular tumor spheroids as a model for assessing delivery of oligonucleotides in three dimensions. MOLECULAR THERAPY. NUCLEIC ACIDS 2014; 3:e153. [PMID: 24618852 PMCID: PMC4027982 DOI: 10.1038/mtna.2014.5] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 01/17/2014] [Indexed: 01/13/2023]
Abstract
Oligonucleotides have shown promise in selectively manipulating gene expression in vitro, but that success has not translated to the clinic for cancer therapy. A potential reason for this is that cells behave differently in monolayer than in the three-dimensional tumor, resulting in limited penetration and distribution of oligonucleotides in the tumor. This may be especially true when oligonucleotides are associated with nanocarriers such as lipoplexes and polyplexes, commonly used delivery vehicles for oligonucleotides. The multicellular tumor spheroid (MCTS), a three-dimensional model that closely resembles small avascular tumors and micrometastases, has been utilized as an intermediate between monolayer culture and in vivo studies for the screening of small-molecule drugs. However, spheroids have been little used for the study of various oligonucleotide delivery formulations. Here, we have evaluated the uptake and efficacy of splice-switching antisense oligonucleotides using various delivery modalities in two- and three-dimensional culture models. We find that the size of the delivery agent dramatically influences penetration into the spheroid and thus the biological effect of the oligonucleotides. We hypothesize that the MCTS model will prove to be a useful tool in the future development of oligonucleotide delivery formulations.
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60
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Abstract
Photochemical internalization (PCI) is a method for releasing macromolecules from endosomal and lysosomal compartments. The PCI approach uses a photosensitizer that localizes to endosomal and lysosomal compartments, and a light source with appropriate light spectra for excitation of the photosensitizer. Upon photosensitizer excitation, endosomal and lysosomal membranes are destroyed, due to the formation of reactive oxygen species, followed by release of the endocytosed material. PCI has been demonstrated to enhance and control (site- and time-specific) delivery of various macromolecules such as viruses, proteins, chemotherapeutics, nucleic acid, and so on. In this Review we present past and current studies of PCI-controlled delivery of natural and artificial nucleic acids, such as peptide nucleic acids, siRNA molecules, mRNA molecules and plasmids. We also discuss critical aspects to further the possibilities for successful gene targeting in space and time.
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61
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62
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Ko YT. Nanoparticle-mediated delivery of oligonucleotides to the blood-brain barrier: in vitro and in situ brain perfusion studies on the uptake mechanisms. J Drug Target 2013; 21:866-73. [PMID: 23952765 DOI: 10.3109/1061186x.2013.829077] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Except for the few exceptions where topical administration is feasible, progress towards broad clinical application of nucleic acid therapeutics requires development of effective systemic delivery strategies. The central nervous system represents a particularly difficult organ for systemic delivery due to the blood-brain barrier. We previously reported a nanoparticulate delivery system for targeted brain delivery of oligonucleotides upon systemic administration, i.e. liposome-encapsulated polyethylenimine/oligonucleotides polyplexes. In this study, cellular uptake and intracellular trafficking of the nanoparticles were further investigated using in situ brain perfusion technique followed by colocalization and fluorescence resonance energy transfer techniques. The brain endothelial uptake and possibly parenchymal accumulation were readily visualized upon administration via internal carotid artery perfusion. The nanoparticles were colocalized with early-endosome antigen, which confirms the brain endothelial uptake through transferrin receptor-mediated endocytosis. Fluorescence resonance energy transfer analysis also suggested the nanoparticles entered the brain endothelial cells while maintaining their integrity. Together, the enhanced brain uptake, as claimed previously, of the antibody-targeted nanoparticles was clearly confirmed with more convincing evidences. In addition, the experimental techniques described here should be applicable to the studies involving nanoparticle-mediated brain delivery of nucleic acid therapeutics.
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Affiliation(s)
- Young Tag Ko
- College of Pharmacy, Gachon University , Incheon , South Korea
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63
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Albumin-based nanoconjugates for targeted delivery of therapeutic oligonucleotides. Biomaterials 2013; 34:7939-49. [PMID: 23876758 DOI: 10.1016/j.biomaterials.2013.06.066] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 06/28/2013] [Indexed: 12/20/2022]
Abstract
Nanoparticle-based delivery has become an important strategy to advance siRNA and antisense oligonucleotides into clinical reality. However, limited biodistribution of nanoparticles and the toxicity of some nanocarriers restrict the wider application of this strategy. To address these issues we aimed to construct oligonucleotide delivery systems which are non-cytotoxic and smaller than typical nanoparticles. Thus, a morpholino oligonucleotide was conjugated to a tumor-targeting RGD peptide, and then, multiple RGD-oligo conjugates were linked to a single molecule of human serum albumin via a reductively responsive linkage. The resultant nanoconjugates showed uniform and monodispersed size distribution with a diameter of 13 nm. A single nanoconjugate molecule contains 15 oligonucleotides as well as 15 targeting ligands on the surface of albumin. The nanoparticle demonstrated 61-fold enhancement in receptor-specific cellular delivery of oligonucleotides in integrin-expressing tumor cells compared to the non-targeted control nanoconjugates and were able to robustly enhance functional activity of the oligonucleotide at low nanomolar concentrations without causing cytotoxicity. Due to their small size, the targeted nanoconjugates could penetrate deeply and distribute throughout 3-D tumor spheroids, whereas the conventional nanoparticles with sizes over 300 nm could only deliver to the cells on the surface of the tumor spheroids. As a result of their greater cellular delivery, smaller size, and lack of cytotoxicity compared to conventional nanoparticles, the multivalent nanoconjugates may provide an effective tool for targeting oligonucleotides to tumors and other diseased tissues.
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64
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Alam MR, Ming X, Nakagawa O, Jin J, Juliano RL. Covalent conjugation of oligonucleotides with cell-targeting ligands. Bioorg Med Chem 2013; 21:6217-23. [PMID: 23777829 DOI: 10.1016/j.bmc.2013.05.037] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 04/30/2013] [Accepted: 05/17/2013] [Indexed: 12/16/2022]
Abstract
A continuing problem in the area of oligonucleotide-based therapeutics is the poor access of these molecules to their sites of action in the nucleus or cytosol. A number of approaches to this problem have emerged. One of the most interesting is the use of ligand-oligonucleotide conjugates to promote receptor mediated cell uptake and delivery. Here we provide an overview of recent developments regarding targeted conjugates, including use of peptides, carbohydrates and small molecules as ligands. Additionally we discuss our own experience with this approach and point out both advantages and limitations.
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Affiliation(s)
- Md Rowshon Alam
- Division of Molecular Pharmaceutics, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599, United States; NITTO DENKO Avecia, 8560 Reading Road, Cincinnati, OH 45215, United States
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65
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Wahlestedt C. Targeting long non-coding RNA to therapeutically upregulate gene expression. Nat Rev Drug Discov 2013; 12:433-46. [DOI: 10.1038/nrd4018] [Citation(s) in RCA: 396] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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66
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Akhtar S, Chandrasekhar B, Attur S, Yousif MHM, Benter IF. On the nanotoxicity of PAMAM dendrimers: Superfect® stimulates the EGFR-ERK1/2 signal transduction pathway via an oxidative stress-dependent mechanism in HEK 293 cells. Int J Pharm 2013; 448:239-46. [PMID: 23538097 DOI: 10.1016/j.ijpharm.2013.03.039] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Revised: 03/17/2013] [Accepted: 03/18/2013] [Indexed: 12/22/2022]
Abstract
Polyamidoamine (PAMAM) dendrimers are cationic branch-like macromolecules that may serve as drug delivery systems for gene-based therapies such as RNA interference. For their safe use in the clinic, they should ideally only enhance drug delivery to target tissues and exhibit no adverse effects. However, little is known about their toxicological profiles in terms of their interactions with cellular signal transduction pathways such as the epidermal growth factor receptor (EGFR). The EGFR is an important signaling cascade that regulates cell growth, differentiation, migration, survival and apoptosis. Here, we investigated the impact of naked, unmodified Superfect (SF), a commercially available generation 6 PAMAM dendrimer, on the epidermal growth factor receptor (EGFR) tyrosine kinase-extracellular-regulated kinase 1/2 (ERK1/2) signaling pathway in human embryonic kidney (HEK 293) cells. At concentrations routinely used for transfection, SF exhibited time and dose-dependent stimulation of EGFR and ERK1/2 phosphorylation whereas AG1478, a selective EGFR tyrosine kinase antagonist, inhibited EGFR-ERK1/2 signaling. SF-induced phosphorylation of EGFR for 1h was partly reversible upon removal of the dendrimer and examination of cells 24 later. Co-treatment of SF with epidermal growth factor (EGF) ligand resulted in greater EGFR stimulation than either agent alone implying that the stimulatory effects of SF and the ligand are synergistic. Dendrimer-induced stimulation of EGFR-ERK1/2 signaling could be attenuated by the antioxidants apocynin, catalase and tempol implying that an oxidative stress dependent mechanism was involved. These results show for the first time that PAMAM dendrimers, aside from their ability to improve drug delivery, can modulate the important EGFR-ERK1/2 cellular signal transduction pathway - a novel finding that may have a bearing on their safe application as drug delivery systems.
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Affiliation(s)
- Saghir Akhtar
- Department of Pharmacology and Toxicology, Faculty of Medicine, Kuwait University, Kuwait.
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