601
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Shi B, Abrams M. Technologies for investigating the physiological barriers to efficient lipid nanoparticle-siRNA delivery. J Histochem Cytochem 2013; 61:407-20. [PMID: 23504369 PMCID: PMC3715328 DOI: 10.1369/0022155413484152] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 02/20/2013] [Indexed: 11/22/2022] Open
Abstract
Small interfering RNA (siRNA) therapeutics have advanced from bench to clinical trials in recent years, along with new tools developed to enable detection of siRNA delivered at the organ, cell, and subcellular levels. Preclinical models of siRNA delivery have benefitted from methodologies such as stem-loop quantitative polymerase chain reaction, histological in situ immunofluorescent staining, endosomal escape assay, and RNA-induced silencing complex loading assay. These technologies have accelerated the detection and optimization of siRNA platforms to overcome the challenges associated with delivering therapeutic oligonucleotides to the cytosol of specific target cells. This review focuses on the methodologies and their application in the biodistribution of siRNA delivered by lipid nanoparticles.
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Affiliation(s)
- Bin Shi
- Department of RNA Therapeutics, Merck Research Laboratories, Merck & Co., Inc., West Point, Pennsylvania, USA.
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602
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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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603
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Slagter-Jäger JG, Raney A, Lewis WE, DeBenedette MA, Nicolette CA, Tcherepanova IY. Evaluation of RNA Amplification Methods to Improve DC Immunotherapy Antigen Presentation and Immune Response. MOLECULAR THERAPY. NUCLEIC ACIDS 2013; 2:e91. [PMID: 23653155 PMCID: PMC4817939 DOI: 10.1038/mtna.2013.18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 03/19/2013] [Indexed: 01/07/2023]
Abstract
Dendritic cells (DCs) transfected with total amplified tumor cell RNA have the potential to induce broad antitumor immune responses. However, analytical methods required for quantitatively assessing the integrity, fidelity, and functionality of the amplified RNA are lacking. We have developed a series of assays including gel electrophoresis, northern blot, capping efficiency, and microarray analysis to determine integrity and fidelity and a model system to assess functionality after transfection into human DCs. We employed these tools to demonstrate that modifications to our previously reported total cellular RNA amplification process including the use of the Fast Start High Fidelity (FSHF) PCR enzyme, T7 Powerswitch primer, post-transcriptional capping and incorporation of a type 1 cap result in amplification of longer transcripts, greater translational competence, and a higher fidelity representation of the starting total RNA population. To study the properties of amplified RNA after transfection into human DCs, we measured protein expression levels of defined antigens coamplified with the starting total RNA populations and measured antigen-specific T cell expansion in autologous DC-T cell co-cultured in vitro. We conclude from these analyses that the improved RNA amplification process results in superior protein expression levels and a greater capacity of the transfected DCs to induce multifunctional antigen-specific memory T cells.Molecular Therapy-Nucleic Acids (2013) 2, e91; doi:10.1038/mtna.2013.18; published online 7 May 2013.
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Affiliation(s)
| | - Alexa Raney
- Novartis, Holly Springs, North Carolina, USA
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604
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Takemoto H, Miyata K, Hattori S, Ishii T, Suma T, Uchida S, Nishiyama N, Kataoka K. Acidic pH-Responsive siRNA Conjugate for Reversible Carrier Stability and Accelerated Endosomal Escape with Reduced IFNα-Associated Immune Response. Angew Chem Int Ed Engl 2013; 52:6218-21. [DOI: 10.1002/anie.201300178] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 02/25/2013] [Indexed: 01/30/2023]
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605
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Takemoto H, Miyata K, Hattori S, Ishii T, Suma T, Uchida S, Nishiyama N, Kataoka K. Acidic pH-Responsive siRNA Conjugate for Reversible Carrier Stability and Accelerated Endosomal Escape with Reduced IFNα-Associated Immune Response. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201300178] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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606
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607
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Sakurai Y, Hatakeyama H, Sato Y, Hyodo M, Akita H, Harashima H. Gene silencing via RNAi and siRNA quantification in tumor tissue using MEND, a liposomal siRNA delivery system. Mol Ther 2013; 21:1195-203. [PMID: 23568259 DOI: 10.1038/mt.2013.57] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Small interfering RNA (siRNA) would be predicted to function as a cancer drug, but an efficient siRNA delivery system is required for clinical development. To address this issue, we developed a liposomal siRNA carrier, a multifunctional envelope-type nanodevice (MEND). We previously reported that a MEND composed of a pH-sensitive cationic lipid, YSK05, showed significant knockdown in both in vitro and in tumor tissue by intratumoral injection. Here, we report on the development of an in vivo siRNA delivery system that is delivered by systemic injection and an analysis of the pharmacokinetics of an intravenously administered siRNA molecule in tumor tissue. Tumor delivery of siRNA was quantified by means of stem-loop primer quantitative reverse transcriptase PCR (qRT-PCR) method. PEGylation of the YSK-MEND results in the increase in the accumulation of siRNA in tumor tissue from 0.0079% ID/g tumor to 1.9% ID/g tumor. The Administration of the MEND (3 mg siRNA/kg body weight) showed about a 50% reduction in the target gene mRNA and protein. Moreover, we verified the induction of RNA interference by 5' RACE-PCR method. The collective results reported here indicate that an siRNA carrier was developed that can deliver siRNA to a target cell in tumor tissue through an improved siRNA bioavailability.
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Affiliation(s)
- Yu Sakurai
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
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608
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Eicher SC, Dehio C. Systems-level analysis of host-pathogen interaction using RNA interference. N Biotechnol 2013; 30:308-13. [PMID: 23395778 DOI: 10.1016/j.nbt.2013.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 01/16/2013] [Indexed: 10/27/2022]
Abstract
Hand-in-hand with the availability of full genome sequences for eukaryotic model organisms and humans the demand for analysis of gene function on a system level has grown. In a process called RNA interference (RNAi) specific mRNA species can be degraded by introduction of double-stranded small interfering RNAs (siRNAs) that are complementary to the targeted transcript sequence. This enables the selective impairment of gene function. During the past decade RNAi has been exploited in many different eukaryotic cell types and model organisms. Large-scale and eventually genome-wide RNAi screens ablating gene functions in a systematic manner have delivered an overwhelming amount of data on the requirement of distinct gene products for major cellular pathways. A large part of the RNAi field is dedicated to disease states such as cancer or infection with the prospect of discovering pathways suitable for new therapeutic interventions. Here some of the major steps in the development of the RNAi technology will be outlined and exemplified with a focus on the progress made in the field of mammalian host-pathogen interactions.
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Affiliation(s)
- Simone C Eicher
- Focal Area Infection Biology, Biozentrum of the University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
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609
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Zeng H, Little HC, Tiambeng TN, Williams GA, Guan Z. Multifunctional Dendronized Peptide Polymer Platform for Safe and Effective siRNA Delivery. J Am Chem Soc 2013; 135:4962-5. [DOI: 10.1021/ja400986u] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Hanxiang Zeng
- Department of Chemistry, 1102 Natural
Sciences 2, University of California, Irvine, California 92697-2025,
United States
| | - Hannah C. Little
- Department of Chemistry, 1102 Natural
Sciences 2, University of California, Irvine, California 92697-2025,
United States
| | - Timothy N. Tiambeng
- Department of Chemistry, 1102 Natural
Sciences 2, University of California, Irvine, California 92697-2025,
United States
| | - Gregory A. Williams
- Department of Chemistry, 1102 Natural
Sciences 2, University of California, Irvine, California 92697-2025,
United States
| | - Zhibin Guan
- Department of Chemistry, 1102 Natural
Sciences 2, University of California, Irvine, California 92697-2025,
United States
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610
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Hernandez LI, Flenker KS, Hernandez FJ, Klingelhutz AJ, II JOM, Giangrande PH. Methods for Evaluating Cell-Specific, Cell-Internalizing RNA Aptamers. Pharmaceuticals (Basel) 2013; 6:295-319. [PMID: 23894227 PMCID: PMC3722562 DOI: 10.3390/ph6030295] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Recent clinical trials of small interfering RNAs (siRNAs) highlight the need for robust delivery technologies that will facilitate the successful application of these therapeutics to humans. Arguably, cell targeting by conjugation to cell-specific ligands provides a viable solution to this problem. Synthetic RNA ligands (aptamers) represent an emerging class of pharmaceuticals with great potential for targeted therapeutic applications. For targeted delivery of siRNAs with aptamers, the aptamer-siRNA conjugate must be taken up by cells and reach the cytoplasm. To this end, we have developed cell-based selection approaches to isolate aptamers that internalize upon binding to their cognate receptor on the cell surface. Here we describe methods to monitor for cellular uptake of aptamers. These include: (1) antibody amplification microscopy, (2) microplate-based fluorescence assay, (3) a quantitative and ultrasensitive internalization method (“QUSIM”) and (4) a way to monitor for cytoplasmic delivery using the ribosome inactivating protein-based (RNA-RIP) assay. Collectively, these methods provide a toolset that can expedite the development of aptamer ligands to target and deliver therapeutic siRNAs in vivo.
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Affiliation(s)
- Luiza I. Hernandez
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA; E-Mails: (L.I.H); (K.S.F); frank (F.J.H); (J.O.M)
| | - Katie S. Flenker
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA; E-Mails: (L.I.H); (K.S.F); frank (F.J.H); (J.O.M)
| | - Frank J. Hernandez
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA; E-Mails: (L.I.H); (K.S.F); frank (F.J.H); (J.O.M)
| | - Aloysius J. Klingelhutz
- Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA; E-Mail:
- Department of Radiation Oncology, University of Iowa, Iowa City, IA 52242, USA
- Molecular & Cellular Biology Program, University of Iowa, Iowa City, IA 52242, USA
| | - James O. McNamara II
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA; E-Mails: (L.I.H); (K.S.F); frank (F.J.H); (J.O.M)
- Molecular & Cellular Biology Program, University of Iowa, Iowa City, IA 52242, USA
| | - Paloma H. Giangrande
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA; E-Mails: (L.I.H); (K.S.F); frank (F.J.H); (J.O.M)
- Department of Radiation Oncology, University of Iowa, Iowa City, IA 52242, USA
- Molecular & Cellular Biology Program, University of Iowa, Iowa City, IA 52242, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-319-384-3242; Fax: +1-319-353-5552
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611
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Martínez T, Wright N, López-Fraga M, Jiménez AI, Pañeda C. Silencing human genetic diseases with oligonucleotide-based therapies. Hum Genet 2013; 132:481-93. [PMID: 23494242 DOI: 10.1007/s00439-013-1288-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Accepted: 03/05/2013] [Indexed: 12/11/2022]
Abstract
RNA interference is an endogenous mechanism present in most eukaryotic cells that enables degradation of specific mRNAs. Pharmacological exploitation of this mechanism for therapeutic purposes attracted a whole amount of attention in its initial years, but was later hampered due to difficulties in delivery of the pharmacological agents to the appropriate organ or tissue. Advances in recent years have to a certain level started to address this specific issue. Genetic diseases are caused by aberrations in gene sequences or structure; these particular abnormalities are in theory easily addressable by RNAi therapeutics. Sequencing of the human genome has largely contributed to the identification of alterations responsible for genetic conditions, thus facilitating the design of compounds that can address these diseases. This review addresses the currently on-going programs with the aim of developing RNAi and other antisense compounds for the treatment of genetic conditions and the pros and cons that these products may encounter along the way. The authors have focused on those programs that have reached clinical trials or are very close to do so.
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Affiliation(s)
- Tamara Martínez
- Sylentis, PCM C/Santiago Grisolía no 2, Tres Cantos, 28760, Madrid, Spain
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612
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Abstract
Immunotherapeutic approaches have been gaining attention in the field of cancer treatment because of their possible ability to eradicate cancer cells as well as metastases by recruiting the host immune system. On the other hand, RNA-based therapeutics with the ability to silence expression of specific targets are currently under clinical investigation for various disorders including cancer. As the mechanisms of tumor evasion from the host immune system are versatile, different molecules have the capacity to be targeted by RNAi technology in order to enhance the immune response against tumors. This technology has been used to silence specific targets in tumor cells, as well as immune cells in cancer cell lines, animal models and clinical trials. siRNAs can also stimulate innate immune responses through activation of Toll-like receptors. Although currently clinical trials of the application of siRNA in cancer immunotherapy are few, it is predicted that in future this technology will be used broadly in cancer treatment.
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Affiliation(s)
- Soudeh Ghafouri-Fard
- Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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613
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Wu SY, Chen TM, Gmeiner WH, Chu E, Schmitz JC. Development of modified siRNA molecules incorporating 5-fluoro-2'-deoxyuridine residues to enhance cytotoxicity. Nucleic Acids Res 2013; 41:4650-9. [PMID: 23449220 PMCID: PMC3632118 DOI: 10.1093/nar/gkt120] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Therapeutic small interfering RNAs (siRNAs) are composed of chemically modified nucleotides, which enhance RNA stability and increase affinity in Watson–Crick base pairing. However, the precise fate of such modified nucleotides once the siRNA is degraded within the cell is unknown. Previously, we demonstrated that deoxythymidine release from degraded siRNAs reversed the cytotoxicity of thymidylate synthase (TS)-targeted siRNAs and other TS inhibitor compounds. We hypothesized that siRNAs could be designed with specific nucleoside analogues that, once released, would enhance siRNA cytotoxicity. TS-targeted siRNAs were designed that contained 5-fluoro-2′-deoxyuridine (FdU) moieties at various locations within the siRNA. After transfection, these siRNAs suppressed TS protein and messenger RNA expression with different efficiencies depending on the location of the FdU modification. FdU was rapidly released from the siRNA as evidenced by formation of the covalent inhibitory ternary complex formed between TS protein and the FdU metabolite, FdUMP. These modified siRNAs exhibited 10–100-fold greater cytotoxicity and induced multiple DNA damage repair and apoptotic pathways when compared with control siRNAs. The strategy of designing siRNA molecules that incorporate cytotoxic nucleosides represents a potentially novel drug development approach for the treatment of cancer and other human diseases.
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Affiliation(s)
- Shao-yu Wu
- Division of Hematology-Oncology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15232, USA
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614
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Chen S, Ge X, Chen Y, Lv N, Liu Z, Yuan W. Advances with RNA interference in Alzheimer's disease research. DRUG DESIGN DEVELOPMENT AND THERAPY 2013; 7:117-25. [PMID: 23459401 PMCID: PMC3582316 DOI: 10.2147/dddt.s40229] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized clinically by memory and cognitive dysfunction. Unfortunately, there is no effective therapeutic method for AD treatment or ways to halt disease progression. Many mechanisms are involved in the disease, including genes mutation and protein dysfunction. RNA interference (RNAi) technology may potentially be able to control AD. It can inhibit the protein expression of specific genes by activating a sequence-specific RNA degradation process. This is a powerful tool with which to study gene function, investigate the mechanism of the disease, and validate drug targets. In this review, we highlight the advances in RNAi technology in the investigation and treatment of AD.
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Affiliation(s)
- Shun Chen
- Department of Neurology, Xinhua Hospital affiliated to Shanghai Jiaotong University School of Medicine, Shanghai Jiaotong University, Shanghai
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615
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Abstract
Mantle cell lymphoma (MCL) is a rare and aggressive subtype of non-Hodgkin lymphoma. New treatment modalities, including intensive induction regimens with immunochemotherapy and autologous stem cell transplant, have improved survival. However, many patients still relapse, and there is a need for novel therapeutic strategies. Recent progress has been made in the understanding of the role of microRNAs (miRNAs) in MCL. Comparisons of tumor samples from patients with MCL with their normal counterparts (naive B-cells) have identified differentially expressed miRNAs with roles in cellular growth and survival pathways, as demonstrated in various biological model systems. In addition, MCL clinico-pathological and prognostic subtypes can be identified using individual miRNAs or miRNA classifiers. miRNA based therapies have now shown efficacy in animal models, and many efforts are currently being made to further develop these drugs for use in patients. Thus, there is hope that specific targeting of pathogenic miRNAs may be used in cases of MCL when conventional therapies fail. Here, we review the current knowledge about the role of miRNAs in MCL, and highlight the perspectives for clinical use.
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Affiliation(s)
- Simon Husby
- Department of Hematology, Rigshospitalet, Denmark
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616
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Nimitvilai S, Arora DS, McElvain MA, Brodie MS. Suppression of Gq Function Using Intra-Pipette Delivery of shRNA during Extracellular Recording in the Ventral Tegmental Area. Front Cell Neurosci 2013; 7:7. [PMID: 23408114 PMCID: PMC3569574 DOI: 10.3389/fncel.2013.00007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 01/16/2013] [Indexed: 11/13/2022] Open
Abstract
Selective suppression of protein function in the brain can be achieved using specific silencing RNAs administered in vivo. A viral delivery system is often employed to transfect neurons with small hairpin RNA (shRNA) directed against specific proteins, and intervals of several days are allowed between microinjection of the shRNA-containing virus into the brain and experiments to assess suppression of gene function. Here we report studies using extracellular recording of dopaminergic neurons of the ventral tegmental area (DA VTA neurons) recorded in brain slices in which lentivirus containing shRNA directed against Gq was included in the recording pipette, and suppression of Gq-related function was observed within the time frame of the recording. The action of neurotensin (NT) is associated with activation of Gq, and the firing rate of DA VTA neurons is increased by NT. With shRNA directed against Gq in the pipette, there was a significant reduction of NT excitation within 2 h. Likewise, time-dependent dopamine desensitization, which we have hypothesized to be Gq-dependent, was not observed when shRNA directed against Gq was present in the pipette and dopamine was tested 2 h after initiation of recording. As the time interval (2 h) is relatively short, we tested whether blockade of protein synthesis with cycloheximide delivered via the recording pipette would alter Gq-linked responses similarly. Both NT-induced excitation and dopamine desensitization were inhibited in the presence of cycloheximide. Inclusion of shRNA in the recording pipette may be an efficient and selective way to dampen responses linked to Gq, and, more generally, the use of lentiviral-packaged shRNA in the recording pipette is a means to produce selective inhibition of the function of specific proteins in experiments.
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Affiliation(s)
- Sudarat Nimitvilai
- Department of Physiology and Biophysics, University of Illinois at Chicago Chicago, IL, USA
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617
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Recent Advances in Ribonucleic Acid Interference (RNAi). NATIONAL ACADEMY SCIENCE LETTERS 2013. [DOI: 10.1007/s40009-012-0102-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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618
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Doluca O, Withers JM, Filichev VV. Molecular engineering of guanine-rich sequences: Z-DNA, DNA triplexes, and G-quadruplexes. Chem Rev 2013; 113:3044-83. [PMID: 23391174 DOI: 10.1021/cr300225q] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Osman Doluca
- Institute of Fundamental Sciences, Massey University, Private Bag 11 222, Palmerston North, New Zealand
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619
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Abstract
The unexpected discovery that somatic cells can be reprogrammed to a pluripotent state yielding induced pluripotent stem cells has made it possible to produce cardiovascular cells exhibiting inherited traits and disorders. Use of these cells in high throughput analyses should broaden our insight into fundamental disease mechanisms and provide many benefits for patients, including new therapeutics and individually tailored therapies. Here we review recent progress in generating induced pluripotent stem cell-based models of cardiovascular disease and their multiple applications in drug development.
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Affiliation(s)
- Mark Mercola
- Muscle Development and Regeneration Program, Sanford-Burnham Medical Research Institute, 10901 North Torrey Pines Rd, La Jolla, CA 92037, USA.
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620
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Peterson CW, Younan P, Jerome KR, Kiem HP. Combinatorial anti-HIV gene therapy: using a multipronged approach to reach beyond HAART. Gene Ther 2013; 20:695-702. [PMID: 23364313 DOI: 10.1038/gt.2012.98] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 11/19/2012] [Accepted: 11/22/2012] [Indexed: 12/11/2022]
Abstract
The 'Berlin Patient', who maintains suppressed levels of HIV viremia in the absence of antiretroviral therapy, continues to be a standard bearer in HIV eradication research. However, the unique circumstances surrounding his functional cure are not applicable to most HIV(+) patients. To achieve a functional or sterilizing cure in a greater number of infected individuals worldwide, combinatorial treatments, targeting multiple stages of the viral life cycle, will be essential. Several anti-HIV gene therapy approaches have been explored recently, including disruption of the C-C chemokine receptor 5 (CCR5) and CXC chemokine receptor 4 (CXCR4) coreceptor loci in CD4(+) T cells and CD34(+) hematopoietic stem cells. However, less is known about the efficacy of these strategies in patients and more relevant HIV model systems such as non-human primates (NHPs). Combinatorial approaches, including genetic disruption of integrated provirus, functional enhancement of endogenous restriction factors and/or the use of pharmacological adjuvants, could amplify the anti-HIV effects of CCR5/CXCR4 gene disruption. Importantly, delivering gene disruption molecules to genetic sites of interest will likely require optimization on a cell type-by-cell type basis. In this review, we highlight the most promising gene therapy approaches to combat HIV infection, methods to deliver these therapies to hematopoietic cells and emphasize the need to target viral replication pre- and post-entry to mount a suitably robust defense against spreading infection.
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Affiliation(s)
- C W Peterson
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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621
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Chan CN, Dietrich I, Hosie MJ, Willett BJ. Recent developments in human immunodeficiency virus-1 latency research. J Gen Virol 2013; 94:917-932. [PMID: 23364195 PMCID: PMC3709588 DOI: 10.1099/vir.0.049296-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Almost 30 years after its initial discovery, infection with the human immunodeficiency virus-1 (HIV-1) remains incurable and the virus persists due to reservoirs of latently infected CD4(+) memory T-cells and sanctuary sites within the infected individual where drug penetration is poor. Reactivating latent viruses has been a key strategy to completely eliminate the virus from the host, but many difficulties and unanswered questions remain. In this review, the latest developments in HIV-persistence and latency research are presented.
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Affiliation(s)
- Chi Ngai Chan
- MRC-University of Glasgow Centre for Virus Research, Bearsden Road, Glasgow G61 1QH, UK
| | - Isabelle Dietrich
- MRC-University of Glasgow Centre for Virus Research, Bearsden Road, Glasgow G61 1QH, UK
| | - Margaret J Hosie
- MRC-University of Glasgow Centre for Virus Research, Bearsden Road, Glasgow G61 1QH, UK
| | - Brian J Willett
- MRC-University of Glasgow Centre for Virus Research, Bearsden Road, Glasgow G61 1QH, UK
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622
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Fulkerson PC, Rothenberg ME. Targeting eosinophils in allergy, inflammation and beyond. Nat Rev Drug Discov 2013; 12:117-29. [PMID: 23334207 DOI: 10.1038/nrd3838] [Citation(s) in RCA: 335] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Eosinophils can regulate local immune and inflammatory responses, and their accumulation in the blood and tissue is associated with several inflammatory and infectious diseases. Thus, therapies that target eosinophils may help control diverse diseases, including atopic disorders such as asthma and allergy, as well as diseases that are not primarily associated with eosinophils, such as autoimmunity and malignancy. Eosinophil-targeted therapeutic agents that are aimed at blocking specific steps involved in eosinophil development, migration and activation have recently entered clinical testing and have produced encouraging results and insights into the role of eosinophils. In this Review, we describe recent advances in the development of first-generation eosinophil-targeted therapies and highlight strategies for using personalized medicine to treat eosinophilic disorders.
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Affiliation(s)
- Patricia C Fulkerson
- Division of Allergy and Immunology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA.
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623
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Nawale GN, Gore KR, Höbartner C, Pradeepkumar PI. Incorporation of 4'-C-aminomethyl-2'-O-methylthymidine into DNA by thermophilic DNA polymerases. Chem Commun (Camb) 2013; 48:9619-21. [PMID: 22908130 DOI: 10.1039/c2cc35222b] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The dual modified nucleotide 4'-C-aminomethyl-2'-O-methylthymidine 5'-triphosphate was synthesized and enzymatically incorporated into DNA by the thermophilic DNA polymerases Pfu and Therminator III. The dual ribose modification imparted increased exonuclease resistance to DNA compared to the well-known 2'-O-methyl modification.
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Affiliation(s)
- Ganesh N Nawale
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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624
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Protein-resistant, reductively dissociable polyplexes for in vivo systemic delivery and tumor-targeting of siRNA. Biomaterials 2013; 34:2370-9. [PMID: 23294546 DOI: 10.1016/j.biomaterials.2012.12.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 12/09/2012] [Indexed: 01/19/2023]
Abstract
Small interfering RNA (siRNA) has been considered as a very attractive therapeutic alternative to chemical drugs; however, the chemical and biological instability and poor delivery efficiency of siRNA limit its success in clinical applications. Here we report a protein-resistant, reductively dissociable siRNA delivery system based on self-assembled polyelectrolyte complexes of dextran-siRNA conjugates linked by disulfide bonds. The prepared polyplexes exhibit excellent dispersion stability in the presence of serum because of the anti-fouling property of dextran exposed onto the complex surface. The enzymatic degradation of siRNA is also effectively suppressed within the complex. Folates are introduced as an active tumor-targeting moiety via the conjugation of folates to the hydroxyl groups of dextran. An in vivo investigation with a xenograft tumor mouse model shows that the folate-decorated dextran-siRNA conjugates are very efficiently targeted to cancer cells and induce sequence-specific gene silencing.
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625
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Contribution of Long Noncoding RNAs to Autism Spectrum Disorder Risk. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2013; 113:35-59. [DOI: 10.1016/b978-0-12-418700-9.00002-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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626
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Lakhin A, Tarantul V, Gening L. Aptamers: problems, solutions and prospects. Acta Naturae 2013; 5:34-43. [PMID: 24455181 PMCID: PMC3890987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aptamers are short single-stranded oligonucleotides that are capable of binding various molecules with high affinity and specificity. When the technology of aptamer selection was developed almost a quarter of a century ago, a suggestion was immediately put forward that it might be a revolutionary start into solving many problems associated with diagnostics and the therapy of diseases. However, multiple attempts to use aptamers in practice, although sometimes successful, have been generally much less efficient than had been expected initially. This review is mostly devoted not to the successful use of aptamers but to the problems impeding the widespread application of aptamers in diagnostics and therapy, as well as to approaches that could considerably expand the range of aptamer application.
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Affiliation(s)
- A.V. Lakhin
- Institute of Molecular Genetics, Russian Academy of Sciences, 2 Kurchatov Sq., Moscow, Russia, 123182
| | - V.Z. Tarantul
- Institute of Molecular Genetics, Russian Academy of Sciences, 2 Kurchatov Sq., Moscow, Russia, 123182
| | - L.V. Gening
- Institute of Molecular Genetics, Russian Academy of Sciences, 2 Kurchatov Sq., Moscow, Russia, 123182
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627
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Shum KT, Zhou J, Rossi JJ. Nucleic Acid Aptamers as Potential Therapeutic and Diagnostic Agents for Lymphoma. ACTA ACUST UNITED AC 2013; 4:872-890. [PMID: 25057429 PMCID: PMC4104705 DOI: 10.4236/jct.2013.44099] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Lymphomas are cancers that arise from white blood cells and usually present as solid tumors. Treatment of lymphoma often involves chemotherapy, and can also include radiotherapy and/or bone marrow transplantation. There is an un-questioned need for more effective therapies and diagnostic tool for lymphoma. Aptamers are single stranded DNA or RNA oligonucleotides whose three-dimensional structures are dictated by their sequences. The immense diversity in function and structure of nucleic acids enable numerous aptamers to be generated through an iterative in vitro selection technique known as Systematic Evolution of Ligands by EXponential enrichment (SELEX). Aptamers have several biochemical properties that make them attractive tools for use as potential diagnostic and pharmacologic agents. Isolated aptamers may directly inhibit the function of target proteins, or they can also be formulated for use as delivery agents for other therapeutic or imaging cargoes. More complex aptamer identification methods, using whole cancer cells (Cell-SELEX), may identify novel targets and aptamers to affect them. This review focuses on recent advances in the use of nucleic acid aptamers as diagnostic and therapeutic agents and as targeted delivery carriers that are relevant to lymphoma. Some representative examples are also discussed.
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Affiliation(s)
- Ka-To Shum
- Department of Molecular and Cellular Biology, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Jiehua Zhou
- Department of Molecular and Cellular Biology, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - John J Rossi
- Department of Molecular and Cellular Biology, Beckman Research Institute of City of Hope, Duarte, CA, USA ; Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of City of Hope, Duarte, CA, USA
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628
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Gouda N, Miyata K, Christie RJ, Suma T, Kishimura A, Fukushima S, Nomoto T, Liu X, Nishiyama N, Kataoka K. Silica nanogelling of environment-responsive PEGylated polyplexes for enhanced stability and intracellular delivery of siRNA. Biomaterials 2013; 34:562-70. [DOI: 10.1016/j.biomaterials.2012.09.077] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 09/29/2012] [Indexed: 12/28/2022]
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629
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Spraggon L, Cartegni L. Antisense Modulation of RNA Processing as a Therapeutic Approach in Cancer Therapy. ACTA ACUST UNITED AC 2013; 10:e139-e148. [PMID: 25589899 DOI: 10.1016/j.ddstr.2013.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Next-generation antisense technologies are re-emerging as viable and powerful approaches to the treatment of several genetic diseases. Similar strategies are also being applied to cancer therapy. Re-programming of the expression of endogenous oncogenic products to replace them with functional antagonists, by interfering with alternative splicing or polyadenylation, provides a promising novel approach to address acquired drug resistance and previously undruggable targets.
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Affiliation(s)
- Lee Spraggon
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, USA
| | - Luca Cartegni
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, USA
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630
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Romanovskaya A, Sarin LP, Bamford DH, Poranen MM. High-throughput purification of double-stranded RNA molecules using convective interaction media monolithic anion exchange columns. J Chromatogr A 2012; 1278:54-60. [PMID: 23332782 DOI: 10.1016/j.chroma.2012.12.050] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 12/20/2012] [Accepted: 12/20/2012] [Indexed: 11/15/2022]
Abstract
Recent advances in the field of RNA interference and new cost-effective approaches for large-scale double-stranded RNA (dsRNA) synthesis have fuelled the demand for robust high-performance purification techniques suitable for dsRNA molecules of various lengths. To address this issue, we developed an improved dsRNA purification method based on anion exchange chromatography utilizing convective interaction media (CIM) monolithic columns. To evaluate column performance we synthesized a selection of dsRNA molecules (58-1810 bp) in a one-step enzymatic reaction involving bacteriophage T7 DNA-dependent RNA polymerase and phi6 RNA-dependent RNA polymerase. In addition, small interfering RNAs (siRNAs) of 25-27 bp were generated by Dicer digestion of the genomic dsRNA of bacteriophage phi6. We demonstrated that linearly scalable CIM monolithic quaternary amine (QA) columns can be used as a fast and superior alternative to standard purification methods (e.g. LiCl precipitation) to obtain highly pure dsRNA preparations. The impurities following Dicer treatment were quickly and efficiently removed with the QA CIM monolithic column, yielding siRNA molecules of high purity suitable for potential therapeutic applications. Moreover, baseline separation of dsRNA molecules up to 1 kb in non-denaturing conditions was achieved.
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Affiliation(s)
- Alesia Romanovskaya
- Department of Biosciences, University of Helsinki, Biocenter 2, P.O. Box 56, 00014 University of Helsinki, Finland
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631
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Singhania R, Khairuddin N, Clarke D, McMillan NA. RNA interference for the treatment of papillomavirus disease. Open Virol J 2012; 6:204-15. [PMID: 23341856 PMCID: PMC3547394 DOI: 10.2174/1874357901206010204] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 08/10/2012] [Accepted: 08/15/2012] [Indexed: 02/06/2023] Open
Abstract
Human Papillomavirus (HPV)-induced diseases are a significant burden on our healthcare system and current therapies are not curative. Vaccination provides significant prophylactic protection but effective therapeutic treatments will still be required. RNA interference (RNAi) has great promise in providing highly specific therapies for all HPV diseases yet this promise has not been realised. Here we review the research into RNAi therapy for HPV in vitro and in vivo and examine the various targets and outcomes. We discuss the idea of using RNAi with current treatments and address delivery of RNAi, the major issue holding back clinical adoption. Finally, we present our view of a potential path to the clinic.
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Affiliation(s)
- Richa Singhania
- The University of Queensland Diamantina Institute, Brisbane, Australia
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632
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Deleavey GF, Damha MJ. Designing chemically modified oligonucleotides for targeted gene silencing. ACTA ACUST UNITED AC 2012; 19:937-54. [PMID: 22921062 DOI: 10.1016/j.chembiol.2012.07.011] [Citation(s) in RCA: 423] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2012] [Revised: 06/28/2012] [Accepted: 07/02/2012] [Indexed: 02/07/2023]
Abstract
Oligonucleotides (ONs), and their chemically modified mimics, are now routinely used in the laboratory as a means to control the expression of fundamentally interesting or therapeutically relevant genes. ONs are also under active investigation in the clinic, with many expressing cautious optimism that at least some ON-based therapies will succeed in the coming years. In this review, we will discuss several classes of ONs used for controlling gene expression, with an emphasis on antisense ONs (AONs), small interfering RNAs (siRNAs), and microRNA-targeting ONs (anti-miRNAs). This review provides a current and detailed account of ON chemical modification strategies for the optimization of biological activity and therapeutic application, while clarifying the biological pathways, chemical properties, benefits, and limitations of oligonucleotide analogs used in nucleic acids research.
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Affiliation(s)
- Glen F Deleavey
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, QC H3A 0B8, Canada.
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633
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Hochholzer W, Giugliano RP. Does it make sense to combine statins with other lipid-altering agents following AIM-HIGH, SHARP and ACCORD? Curr Atheroscler Rep 2012; 15:290. [PMID: 23242605 DOI: 10.1007/s11883-012-0290-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Hypercholesterolemia is one of the main risk factors for the development of atherosclerotic diseases. Multiple clinical trials of lipid-lowering agents have demonstrated that lowering cholesterol effectively reduces the risk of cardiovascular events and death. Currently, treatment with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors ("statins") is the most commonly used approach, given their superior efficacy relative to other cholesterol lowering agents. However, not all patients on statin monotherapy achieve target cholesterol levels, and even when cholesterol lowering is successful, significant residual cardiovascular risk remains. There is increasing interest in developing combination cholesterol-modifying therapies that may augment the treatment effect and minimize the side effects of statins. Although there is currently no evidence that any of the potential therapy combinations can improve clinical outcome compared to statin monotherapy alone, results of several large ongoing trials will help to clarify this important field.
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Affiliation(s)
- Willibald Hochholzer
- Universitaets-Herzzentrum Freiburg · Bad Krozingen, Suedring 15, 79189, Bad Krozingen, Germany.
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634
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Puri PL, Mercola M. BAF60 A, B, and Cs of muscle determination and renewal. Genes Dev 2012; 26:2673-83. [PMID: 23222103 DOI: 10.1101/gad.207415.112] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Developmental biologists have defined many of the diffusible and transcription factors that control muscle differentiation, yet we still have only rudimentary knowledge of the mechanisms that dictate whether a myogenic progenitor cell forms muscle versus alternate lineages, including those that can be pathological in a state of disease or degeneration. Clues about the molecular basis for lineage determination in muscle progenitors are only now emerging from studies of chromatin modifications that avail myogenic genes for transcription, together with analysis of the composition and activities of the chromatin-modifying complexes themselves. Here we review recent progress on muscle determination and explore a unifying theme that environmental cues from the stem or progenitor niche control the selection of specific subunit variants of the switch/sucrose nonfermentable (SWI/SNF) chromatin-modifying complex, creating a combinatorial code that dictates whether cells adopt myogenic versus nonmyogenic cell fates. A key component of the code appears to be the mutually exclusive usage of the a, b, and c variants of the 60-kD structural subunit BAF60 (BRG1/BRM-associated factor 60), of which BAF60c is essential to activate both skeletal and cardiac muscle programs. Since chromatin remodeling governs myogenic fate, the combinatorial assembly of the SWI/SNF complex might be targeted to develop drugs aimed at the therapeutic reduction of compensatory fibrosis and fatty deposition in chronic muscular disorders.
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Affiliation(s)
- Pier Lorenzo Puri
- Muscle Development and Regeneration Program, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA.
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635
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Wang TP, Ko NC, Su YC, Wang EC, Severance S, Hwang CC, Shih YT, Wu MH, Chen YH. Advanced aqueous-phase phosphoramidation reactions for effectively synthesizing peptide-oligonucleotide conjugates trafficked into a human cell line. Bioconjug Chem 2012. [PMID: 23199224 DOI: 10.1021/bc300444y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Peptide-oligonucleotide conjugates (POCs) have held promise as effective therapeutic agents in treating microbial infections and human genetic diseases including cancers. In clinical applications, POCs are especially useful to circumvent cellular delivery and specificity problems of oligonucleotides. We previously reported that nucleic acid phosphoramidation reactions performed in aqueous solutions have the potential for facile POC synthesis. Here, we carried out further studies to significantly improve aqueous-phase two-step phosphoramidation reaction yield. Optimized reactions were employed to effectively synthesize POCs for delivery into human A549 cells. We achieved optimization of aqueous-phase two-step phosphoramidation reaction and improved reaction yield by (1) determining appropriate co-solutes and co-solute concentrations to acquire higher reaction yields, (2) exploring a different nucleophilicity of imidazole and its derivatives to stabilize essential nucleic acid phosphorimidazolide intermediates prior to POC formation, and (3) enhancing POC synthesis by increasing reactant nucleophilicity. The advanced two-step phosphoramidation reaction was exploited to effectively conjugate a well-studied cell penetrating peptide, the Tat(48-57) peptide, with oligonucleotides, bridged by either no linkers or a disulfide-containing linker, to have the corresponding POC yields of 47-75%. Phosphoramidation-synthesized POCs showed no cytotoxicity to human A549 cells at studied POC concentrations after 24 h inoculation and were successfully trafficked into the human A549 cell line as demonstrated by flow cytometry, fluorescent microscopy, and confocal laser scanning microscopy study. The current report provides insight into aqueous-phase phosphoramidation reactions, the knowledge of which was used to develop effective strategies for synthesizing POCs with crucial applications including therapeutic agents for medicine.
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Affiliation(s)
- Tzu-Pin Wang
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan.
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636
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Juliano RL, Carver K, Cao C, Ming X. Receptors, endocytosis, and trafficking: the biological basis of targeted delivery of antisense and siRNA oligonucleotides. J Drug Target 2012; 21:27-43. [PMID: 23163768 DOI: 10.3109/1061186x.2012.740674] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The problem of targeted delivery of antisense and siRNA oligonucleotides can be resolved into two distinct aspects. The first concerns devising ligand-oligonucleotide or ligand-carrier moieties that bind with high selectivity to receptors on the cell type of interest and that are efficiently internalized by endocytosis. The second concerns releasing oligonucleotides from pharmacologically inert endomembrane compartments so that they can access RNA in the cytosol or nucleus. In this review, we will address both of these aspects. Thus, we present information on three important receptor families, the integrins, the receptor tyrosine kinases, and the G protein-coupled receptors in terms of their suitability for targeted delivery of oligonucleotides. This includes discussion of receptor abundance, internalization and trafficking pathways, and the availability of suitable high affinity ligands. We also consider the process of oligonucleotide uptake and intracellular trafficking and discuss approaches to modulating these processes in a pharmacologically productive manner. Hopefully, the basic information presented in this review will be of value to investigators involved in designing delivery approaches for oligonucleotides.
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Affiliation(s)
- R L Juliano
- Division of Molecular Pharmaceutics, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599, USA.
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637
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Strategies to Block HIV Transcription: Focus on Small Molecule Tat Inhibitors. BIOLOGY 2012; 1:668-97. [PMID: 24832514 PMCID: PMC4009808 DOI: 10.3390/biology1030668] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 11/06/2012] [Accepted: 11/07/2012] [Indexed: 01/29/2023]
Abstract
After entry into the target cell, the human immunodeficiency virus type I (HIV) integrates into the host genome and becomes a proviral eukaryotic transcriptional unit. Transcriptional regulation of provirus gene expression is critical for HIV replication. Basal transcription from the integrated HIV promoter is very low in the absence of the HIV transactivator of transcription (Tat) protein and is solely dependent on cellular transcription factors. The 5' terminal region (+1 to +59) of all HIV mRNAs forms an identical stem-bulge-loop structure called the Transactivation Responsive (TAR) element. Once Tat is made, it binds to TAR and drastically activates transcription from the HIV LTR promoter. Mutations in either the Tat protein or TAR sequence usually affect HIV replication, indicating a strong requirement for their conservation. The necessity of the Tat-mediated transactivation cascade for robust HIV replication renders Tat one of the most desirable targets for transcriptional therapy against HIV replication. Screening based on inhibition of the Tat-TAR interaction has identified a number of potential compounds, but none of them are currently used as therapeutics, partly because these agents are not easily delivered for an efficient therapy, emphasizing the need for small molecule compounds. Here we will give an overview of the different strategies used to inhibit HIV transcription and review the current repertoire of small molecular weight compounds that target HIV transcription.
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638
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Paris C, Moreau V, Deglane G, Karim L, Couturier B, Bonnet ME, Kedinger V, Messmer M, Bolcato-Bellemin AL, Behr JP, Erbacher P, Lenne-Samuel N. Conjugating phosphospermines to siRNAs for improved stability in serum, intracellular delivery and RNAi-mediated gene silencing. Mol Pharm 2012; 9:3464-75. [PMID: 23148419 DOI: 10.1021/mp300278b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
siRNAs are usually formulated with cationic polymers or lipids to form supramolecular particles capable of binding and crossing the negatively charged cell membrane. However, particles hardly diffuse through tissues when administered in vivo. We therefore are developing cationic siRNAs, composed of an antisense sequence annealed to an oligophosphospermine-conjugated sense strand. Cationic siRNAs have been previously shown to display gene silencing activity in human cell line (Nothisen et al. J. Am. Chem. Soc.2009). We have improved the synthesis, purification and characterization of oligospermine-oligoribonucleotide conjugates which provide cationic siRNAs with enhanced biological activity. We show data supporting their carrier-free intracellular delivery in a molecular, soluble state. Additional results on the relationship between global charge, uptake and silencing activity confirm the requirement for an overall positive charge of the conjugated siRNA in order to enter cells. Importantly, conjugated siRNAs made of natural phosphodiester nucleotides are protected from nuclease degradation by the oligophosphospermine moiety, operate through the RNAi mechanism and mediate specific gene silencing at submicromolar concentration in the presence of serum.
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Affiliation(s)
- Clément Paris
- Polyplus-tranfection SA, Bioparc, Boulevard S. Brant, Illkirch, 67401, France
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639
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Allele-specific gene silencing in two mouse models of autosomal dominant skeletal myopathy. PLoS One 2012; 7:e49757. [PMID: 23152933 PMCID: PMC3495761 DOI: 10.1371/journal.pone.0049757] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 10/17/2012] [Indexed: 12/16/2022] Open
Abstract
We explored the potential of mutant allele-specific gene silencing (ASGS) in providing therapeutic benefit in two established mouse models of the autosomal dominantly-inherited muscle disorders, Malignant Hyperthermia (MH) and Central Core Disease (CCD). Candidate ASGS siRNAs were designed and validated for efficacy and specificity on ryanodine receptor (RyR1) cDNA mini-constructs expressed in HEK293 cells using RT-PCR- and confocal microscopy-based assays. In vivo delivery of the most efficacious identified siRNAs into flexor digitorum brevis (FDB) muscles was achieved by injection/electroporation of footpads of 4–6 month old heterozygous Ryr1Y524S/+ (YS/+) and Ryr1I4895T/+ (IT/+) knock-in mice, established mouse models of MH with cores and CCD, respectively. Treatment of IT/+ mice resulted in a modest rescue of deficits in the maximum rate (∼38% rescue) and magnitude (∼78%) of ligand-induced Ca2+ release that occurred in the absence of a change in the magnitude of electrically-evoked Ca2+ release. Compared to the difference between the caffeine sensitivity of Ca2+ release in FDB fibers from YS/+ and WT mice treated with SCR siRNA (EC50: 1.1 mM versus 4.4 mM, respectively), caffeine sensitivity was normalized in FDB fibers from YS/+ mice following 2 (EC50: 2.8 mM) and 4 week (EC50: 6.6 mM) treatment with YS allele-specific siRNA. Moreover, the temperature-dependent increase in resting Ca2+ observed in FDB fibers from YS/+ mice was normalized to WT levels after 2 weeks of treatment with YS allele-specific siRNA. As determined by quantitative real time PCR, the degree of functional rescue in YS/+ and IT/+ mice correlated well with the relative increase in fractional WT allele expression.
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640
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Ibrišimović M, Kneidinger D, Lion T, Klein R. An adenoviral vector-based expression and delivery system for the inhibition of wild-type adenovirus replication by artificial microRNAs. Antiviral Res 2012; 97:10-23. [PMID: 23127366 PMCID: PMC3552158 DOI: 10.1016/j.antiviral.2012.10.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 10/17/2012] [Accepted: 10/25/2012] [Indexed: 11/28/2022]
Abstract
Human adenoviruses are rarely associated with life-threatening infections in healthy individuals. However, immunocompromised patients, and particularly allogeneic hematopoietic stem cell transplant recipients, are at high risk of developing disseminated and potentially fatal disease. The efficacy of commonly used drugs to treat adenovirus infections (i.e., cidofovir in most cases) is limited, and alternative treatment options are needed. Artificial microRNAs (amiRNAs) are a class of synthetic RNAs resembling cellular miRNAs, and, similar to their natural relatives, can mediate the knockdown of endogenous gene expression. This process, termed RNA interference, can be harnessed to target and potentially silence both cellular and viral genes. In this study, we designed amiRNAs directed against adenoviral E1A, DNA polymerase, and preterminal protein (pTP) mRNAs in order to inhibit adenoviral replication in vitro. For the expression of amiRNA-encoding sequences, we utilized replication-deficient adenoviral vectors. In cells transduced with the recombinant vectors and infected with the wild-type (wt) adenovirus, one particular amiRNA that was directed against the pTP mRNA was capable of decreasing the output of infectious wt virus progeny by 2.6 orders of magnitude. This inhibition rate could be achieved by concatemerizing amiRNA-encoding sequences to allow for high intracellular amiRNA concentrations. Because superinfecting wt virus induces the replication and amplification of the recombinant adenoviral vector, amiRNA concentrations were increased in cells infected with wt adenovirus. Furthermore, a combination of amiRNA expression and treatment of infected cells with cidofovir resulted in additive effects that manifested as a total reduction of infectious virus progeny by greater than 3 orders of magnitude.
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Affiliation(s)
- Mirza Ibrišimović
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, Department of Pediatrics, Medical University of Vienna, Austria
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641
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Zhou J, Bobbin ML, Burnett JC, Rossi JJ. Current progress of RNA aptamer-based therapeutics. Front Genet 2012; 3:234. [PMID: 23130020 PMCID: PMC3486975 DOI: 10.3389/fgene.2012.00234] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 10/15/2012] [Indexed: 01/07/2023] Open
Abstract
Aptamers are single-stranded nucleic acids that specifically recognize and bind tightly to their cognate targets due to their stable three-dimensional structure. Nucleic acid aptamers have been developed for various applications, including diagnostics, molecular imaging, biomarker discovery, target validation, therapeutics, and drug delivery. Due to their high specificity and binding affinity, aptamers directly block or interrupt the functions of target proteins making them promising therapeutic agents for the treatment of human maladies. Additionally, aptamers that bind to cell surface proteins are well suited for the targeted delivery of other therapeutics, such as conjugated small interfering RNAs (siRNA) that induce RNA interference (RNAi). Thus, aptamer-siRNA chimeras may offer dual-functions, in which the aptamer inhibits a receptor function, while the siRNA internalizes into the cell to target a specific mRNA. This review focuses on the current progress and therapeutic potential of RNA aptamers, including the use of cell-internalizing aptamers as cell-type specific delivery vehicles for targeted RNAi. In particular, we discuss emerging aptamer-based therapeutics that provide unique clinical opportunities for the treatment various cancers and neurological diseases.
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Affiliation(s)
- Jiehua Zhou
- Division of Molecular and Cellular Biology, Beckman Research Institute of City of Hope Duarte, CA, USA
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642
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Hickerson RP, Gonzalez-Gonzalez E, Vlassov AV, Li M, Lara MF, Contag CH, Kaspar RL. Intravital fluorescence imaging of small interfering RNA-mediated gene repression in a dual reporter melanoma xenograft model. Nucleic Acid Ther 2012; 22:438-43. [PMID: 23098239 DOI: 10.1089/nat.2012.0364] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Development of RNA interference (RNAi)-based therapeutics has been hampered by the lack of effective and efficient means of delivery. Reliable model systems for screening and optimizing delivery of RNAi-based agents in vivo are crucial for preclinical research aimed at advancing nucleic acid-based therapies. We describe here a dual fluorescent reporter xenograft melanoma model prepared by intradermal injection of human A375 melanoma cells expressing tandem tomato fluorescent protein (tdTFP) containing a small interfering RNA (siRNA) target site as well as enhanced green fluorescent protein (EGFP), which is used as a normalization control. Intratumoral injection of a siRNA specific to the incorporated siRNA target site, complexed with a cationic lipid that has been optimized for in vivo delivery, resulted in 65%±11% knockdown of tdTFP relative to EGFP quantified by in vivo imaging and 68%±10% by reverse transcription-quantitative polymerase chain reaction. No effect was observed with nonspecific control siRNA treatment. This model provides a platform on which siRNA delivery technologies can be screened and optimized in vivo.
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643
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Recent advances in the rational design of silica-based nanoparticles for gene therapy. Ther Deliv 2012. [DOI: 10.4155/tde.12.98] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Gene therapy has attracted much attention in modern society and provides a promising approach for treating genetic disorders, diseases and cancers. Safe and effective vectors are vital tools to deliver genetic molecules to cells. This review summarizes recent advances in the rational design of silica-based nanoparticles and their applications in gene therapy. An overview of different types of genetic agents available for gene therapy is provided. The engineering of various silica nanoparticles is described, which can be used as versatile complexation tools for genetic agents and advanced gene therapy. Several challenges are raised and future research directions in the area of gene therapy using silica-based nanoparticles are proposed.
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644
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Burnett JC, Zaia JA, Rossi JJ. Creating genetic resistance to HIV. Curr Opin Immunol 2012; 24:625-32. [PMID: 22985479 PMCID: PMC3478429 DOI: 10.1016/j.coi.2012.08.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 08/23/2012] [Indexed: 11/26/2022]
Abstract
HIV/AIDS remains a chronic and incurable disease, in spite of the notable successes of combination antiretroviral therapy. Gene therapy offers the prospect of creating genetic resistance to HIV that supplants the need for antiviral drugs. In sight of this goal, a variety of anti-HIV genes have reached clinical testing, including gene-editing enzymes, protein-based inhibitors, and RNA-based therapeutics. Combinations of therapeutic genes against viral and host targets are designed to improve the overall antiviral potency and reduce the likelihood of viral resistance. In cell-based therapies, therapeutic genes are expressed in gene modified T lymphocytes or in hematopoietic stem cells that generate an HIV-resistant immune system. Such strategies must promote the selective proliferation of the transplanted cells and the prolonged expression of therapeutic genes. This review focuses on the current advances and limitations in genetic therapies against HIV, including the status of several recent and ongoing clinical studies.
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Affiliation(s)
- John C. Burnett
- Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - John A. Zaia
- Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - John J. Rossi
- Beckman Research Institute of the City of Hope, Duarte, CA, USA
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645
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Anti-tumor effects of an engineered "killer" transfer RNA. Biochem Biophys Res Commun 2012; 427:148-53. [PMID: 22989754 DOI: 10.1016/j.bbrc.2012.09.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 09/06/2012] [Indexed: 11/21/2022]
Abstract
A hallmark of cancer cells is their ability to continuously divide; and rapid proliferation requires increased protein translation. Elevating levels of misfolded proteins can elicit growth arrest due to ER stress and decreased global translation. Failure to correct prolonged ER stress eventually results in cell death via apoptosis. tRNA(Ser)(AAU) is an engineered human tRNA(Ser) with an anticodon coding for isoleucine. Here we test the possibility that tRNA(Ser)(AAU) can be an effective killing agent of breast cancer cells and can effectively inhibit tumor-formation in mice. We found that tRNA(Ser)(AAU) exert strong effects on breast cancer translation activity, cell viability, and tumor formation. Translation is strongly inhibited by tRNA(Ser)(AAU) in both tumorigenic and non-tumorigenic cells. tRNA(Ser)(AAU) significantly decreased the number of viable cells over time. A short time treatment with tRNA(Ser)(AAU) was sufficient to eliminate breast tumor formation in a xenograft mouse model. Our results indicate that tRNA(Ser)(AAU) can inhibit breast cancer metabolism, growth and tumor formation. This RNA has strong anti-cancer effects and presents an opportunity for its development into an anti-tumor agent. Because tRNA(Ser)(AAU) corrupts the protein synthesis mechanism that is an integral component of the cell, it would be extremely difficult for tumor cells to evolve and develop resistance against this anti-tumor agent.
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646
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Lange MJ, Sharma TK, Whatley AS, Landon LA, Tempesta MA, Johnson MC, Burke DH. Robust suppression of HIV replication by intracellularly expressed reverse transcriptase aptamers is independent of ribozyme processing. Mol Ther 2012; 20:2304-14. [PMID: 22948672 DOI: 10.1038/mt.2012.158] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
RNA aptamers that bind human immunodeficiency virus 1 (HIV-1) reverse transcriptase (RT) also inhibit viral replication, making them attractive as therapeutic candidates and potential tools for dissecting viral pathogenesis. However, it is not well understood how aptamer-expression context and cellular RNA pathways govern aptamer accumulation and net antiviral bioactivity. Using a previously-described expression cassette in which aptamers were flanked by two "minimal core" hammerhead ribozymes, we observed only weak suppression of pseudotyped HIV. To evaluate the importance of the minimal ribozymes, we replaced them with extended, tertiary-stabilized hammerhead ribozymes with enhanced self-cleavage activity, in addition to noncleaving ribozymes with active site mutations. Both the active and inactive versions of the extended hammerhead ribozymes increased inhibition of pseudotyped virus, indicating that processing is not necessary for bioactivity. Clonal stable cell lines expressing aptamers from these modified constructs strongly suppressed infectious virus, and were more effective than minimal ribozymes at high viral multiplicity of infection (MOI). Tertiary stabilization greatly increased aptamer accumulation in viral and subcellular compartments, again regardless of self-cleavage capability. We therefore propose that the increased accumulation is responsible for increased suppression, that the bioactive form of the aptamer is one of the uncleaved or partially cleaved transcripts, and that tertiary stabilization increases transcript stability by reducing exonuclease degradation.
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Affiliation(s)
- Margaret J Lange
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, MO, USA
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647
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Abstract
Persistent infection with cancer risk-related viruses leads to molecular, cellular and immune response changes in host organisms that in some cases direct cellular transformation. Alternative splicing is a conserved cellular process that increases the coding complexity of genomes at the pre-mRNA processing stage. Human and other animal tumour viruses use alternative splicing as a process to maximize their transcriptomes and proteomes. Medical therapeutics to clear persistent viral infections are still limited. However, specific lessons learned in some viruses [e.g. HIV and HCV (hepatitis C virus)] suggest that drug-directed inhibition of alternative splicing could be useful for this purpose. The present review describes the basic mechanisms of constitutive and alternative splicing in a cellular context and known splicing patterns and the mechanisms by which these might be achieved for the major human infective tumour viruses. The roles of splicing-related proteins expressed by these viruses in cellular and viral gene regulation are explored. Moreover, we discuss some currently available drugs targeting SR (serine/arginine-rich) proteins that are the main regulators of constitutive and alternative splicing, and their potential use in treatment for so-called persistent viral infections.
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648
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Chandra PK, Kundu AK, Hazari S, Chandra S, Bao L, Ooms T, Morris GF, Wu T, Mandal TK, Dash S. Inhibition of hepatitis C virus replication by intracellular delivery of multiple siRNAs by nanosomes. Mol Ther 2012; 20:1724-36. [PMID: 22617108 PMCID: PMC3437587 DOI: 10.1038/mt.2012.107] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 04/23/2012] [Indexed: 02/07/2023] Open
Abstract
Sustained antiviral responses of chronic hepatitis C virus (HCV) infection have improved recently by the use of direct-acting antiviral agents along with interferon (IFN)-α and ribavirin. However, the emergence of drug-resistant variants is expected to be a major problem. We describe here a novel combinatorial small interfering RNA (siRNA) nanosome-based antiviral approach to clear HCV infection. Multiple siRNAs targeted to the highly conserved 5'-untranslated region (UTR) of the HCV genome were synthesized and encapsulated into lipid nanoparticles called nanosomes. We show that siRNA can be repeatedly delivered to 100% of cells in culture using nanosomes without toxicity. Six siRNAs dramatically reduced HCV replication in both the replicon and infectious cell culture model. Repeated treatments with two siRNAs were better than a single siRNA treatment in minimizing the development of an escape mutant, resulting in rapid inhibition of viral replication. Systemic administration of combinatorial siRNA-nanosomes is well tolerated in BALB/c mice without liver injury or histological toxicity. As a proof-of-principle, we showed that systemic injections of siRNA nanosomes significantly reduced HCV replication in a liver tumor-xenotransplant mouse model of HCV. Our results indicate that systemic delivery of combinatorial siRNA nanosomes can be used to minimize the development of escape mutants and inhibition of HCV infection.
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Affiliation(s)
- Partha K Chandra
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
| | - Anup K Kundu
- Center for Nanomedicine and Drug Delivery, College of Pharmacy, Xavier University of Louisiana, New Orleans, Louisiana, USA
| | - Sidhartha Hazari
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
| | - Sruti Chandra
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
| | - Lili Bao
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
| | - Tara Ooms
- Department of Comparative Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
| | - Gilbert F Morris
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
| | - Tong Wu
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
| | - Tarun K Mandal
- Center for Nanomedicine and Drug Delivery, College of Pharmacy, Xavier University of Louisiana, New Orleans, Louisiana, USA
| | - Srikanta Dash
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
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649
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Bramsen JB, Kjems J. Development of Therapeutic-Grade Small Interfering RNAs by Chemical Engineering. Front Genet 2012; 3:154. [PMID: 22934103 PMCID: PMC3422727 DOI: 10.3389/fgene.2012.00154] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 07/31/2012] [Indexed: 12/25/2022] Open
Abstract
Recent successes in clinical trials have provided important proof of concept that small interfering RNAs (siRNAs) indeed constitute a new promising class of therapeutics. Although great efforts are still needed to ensure efficient means of delivery in vivo, the siRNA molecule itself has been successfully engineered by chemical modification to meet initial challenges regarding specificity, stability, and immunogenicity. To date, a great wealth of siRNA architectures and types of chemical modification are available for promoting safe siRNA-mediated gene silencing in vivo and, consequently, the choice of design and modification types can be challenging to individual experimenters. Here we review the literature and devise how to improve siRNA performance by structural design and specific chemical modification to ensure potent and specific gene silencing without unwarranted side-effects and hereby complement the ongoing efforts to improve cell targeting and delivery by other carrier molecules.
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Affiliation(s)
- Jesper B Bramsen
- Interdisciplinary Nanoscience Center, Department of Molecular Biology and Genetics, Aarhus University Aarhus C, Denmark
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650
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The highly conserved 5' untranslated region as an effective target towards the inhibition of Enterovirus 71 replication by unmodified and appropriate 2'-modified siRNAs. J Biomed Sci 2012; 19:73. [PMID: 22889374 PMCID: PMC3438048 DOI: 10.1186/1423-0127-19-73] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Accepted: 08/08/2012] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Enterovirus 71 (EV71) is a highly infectious agent that plays an etiological role in hand, foot, and mouth disease. It is associated with severe neurological complications and has caused significant mortalities in recent large-scale outbreaks. Currently, no effective vaccine or specific clinical therapy is available against EV71. METHODS Unmodified 21 nucleotide small interfering RNAs (siRNAs) and classic 2'-modified (2'-O-methylation or 2'-fluoro modification) siRNAs were designed to target highly conserved 5' untranslated region (UTR) of the EV71 genome and employed as anti-EV71 agents. Real-time TaqMan RT-PCR, western blot analysis and plaque assays were carried out to evaluate specific viral inhibition by the siRNAs. RESULTS Transfection of rhabdomyosarcoma (RD) cells with siRNAs targeting the EV71 genomic 5' UTR significantly delayed and alleviated the cytopathic effects of EV71 infection, increased cell viability in EV71-infected RD cells. The inhibitory effect on EV71 replication was sequence-specific and dosage-dependent, with significant corresponding decreases in viral RNA, VP1 protein and viral titer. Appropriate 2'-modified siRNAs exhibited similar RNA interference (RNAi) activity with dramatically increased serum stability in comparison with unmodified counterparts. CONCLUSION Sequences were identified within the highly conserved 5' UTR that can be targeted to effectively inhibit EV71 replication through RNAi strategies. Appropriate 2'-modified siRNAs provide a promising approach to optimizing siRNAs to overcome barriers on RNAi-based antiviral therapies for broader administration.
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