1
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Gelinas AD, Tan TK, Liu S, Jaramillo JG, Chadwick J, Harding AC, Zhang C, Ream BE, Chase CN, Otis MR, Lee T, Schneider DJ, James WS, Janjic N. Broadly neutralizing aptamers to SARS-CoV-2: A diverse panel of modified DNA antiviral agents. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 31:370-382. [PMID: 36714461 PMCID: PMC9859636 DOI: 10.1016/j.omtn.2023.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 01/19/2023] [Indexed: 01/22/2023]
Abstract
Since its discovery, COVID-19 has rapidly spread across the globe and has had a massive toll on human health, with infection mortality rates as high as 10%, and a crippling impact on the world economy. Despite numerous advances, there remains an urgent need for accurate and rapid point-of-care diagnostic tests and better therapeutic treatment options. To contribute chemically distinct, non-protein-based affinity reagents, we report here the identification of modified DNA-based aptamers that selectively bind to the S1, S2, or receptor-binding domain of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein. Several aptamers inhibit the binding of the spike protein to its cell-surface receptor angiotensin-converting enzyme 2 (ACE2) and neutralize authentic SARS-CoV-2 virus in vitro, including all variants of concern. With a high degree of nuclease resistance imparted by the base modifications, these reagents represent a new class of molecules with potential for further development as diagnostics or therapeutics.
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Affiliation(s)
- Amy D. Gelinas
- SomaLogic, Inc., 2945 Wilderness Place, Boulder, CO 80301, USA
| | - Tiong Kit Tan
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Sai Liu
- James & Lillian Martin Centre, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Javier G. Jaramillo
- James & Lillian Martin Centre, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - James Chadwick
- James & Lillian Martin Centre, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Adam C. Harding
- James & Lillian Martin Centre, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Chi Zhang
- SomaLogic, Inc., 2945 Wilderness Place, Boulder, CO 80301, USA
| | - Brian E. Ream
- SomaLogic, Inc., 2945 Wilderness Place, Boulder, CO 80301, USA
| | | | - Matthew R. Otis
- SomaLogic, Inc., 2945 Wilderness Place, Boulder, CO 80301, USA
| | - Thomas Lee
- Department of Biochemistry, University of Colorado, Boulder, JSCBB, C1B90, 3415 Colorado Avenue, Boulder, CO 80303, USA
| | | | - William S. James
- James & Lillian Martin Centre, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
- Corresponding author William S. James, James & Lillian Martin Centre, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
| | - Nebojsa Janjic
- SomaLogic, Inc., 2945 Wilderness Place, Boulder, CO 80301, USA
- Corresponding author Nebojsa Janjic, SomaLogic, Inc., 2945 Wilderness Place, Boulder, CO 80301, USA.
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2
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Chatterjee T, Johnson-Buck A, Walter NG. Highly sensitive protein detection by aptamer-based single-molecule kinetic fingerprinting. Biosens Bioelectron 2022; 216:114639. [PMID: 36037714 DOI: 10.1016/j.bios.2022.114639] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/21/2022] [Accepted: 08/13/2022] [Indexed: 11/28/2022]
Abstract
Sensitive assays of protein biomarkers play critical roles in clinical diagnostics and biomedical research. Such assays typically employ immunoreagents such as monoclonal antibodies that suffer from several drawbacks, including relatively tedious production, significant batch-to-batch variability, and challenges in site-specific, stoichiometric modification with fluorophores or other labels. One proposed alternative to such immunoreagents, nucleic acid aptamers generated by systematic evolution of ligand by exponential enrichment (SELEX), can be chemically synthesized with much greater ease, precision, and reproducibility than antibodies. However, most aptamers exhibit relatively poor affinity, yielding low sensitivity in the assays employing them. Recently, single molecule recognition through equilibrium Poisson sampling (SiMREPS) has emerged as a platform for detecting proteins and other biomarkers with high sensitivity without requiring high-affinity detection probes. In this manuscript, we demonstrate the applicability and advantages of aptamers as detection probes in SiMREPS as applied to two clinically relevant biomarkers, VEGF165 and IL-8, using a wash-free protocol with limits of detection in the low femtomolar range (3-9 fM). We show that the kinetics of existing RNA aptamers can be rationally optimized for use as SiMREPS detection probes by mutating a single nucleotide in the conserved binding region or by shortening the aptamer sequence. Finally, we demonstrate the detection of endogenous IL-8 from human serum at a concentration below the detection limit of commercial ELISAs.
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Affiliation(s)
- Tanmay Chatterjee
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, Michigan, 48109, United States
| | - Alexander Johnson-Buck
- aLight Sciences, Inc., 333 Jackson Plaza Suite 460, Ann Arbor, Michigan, 48103, United States.
| | - Nils G Walter
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, Michigan, 48109, United States.
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3
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Chakraborty B, Das S, Gupta A, Xiong Y, Vyshnavi TV, Kizer ME, Duan J, Chandrasekaran AR, Wang X. Aptamers for Viral Detection and Inhibition. ACS Infect Dis 2022; 8:667-692. [PMID: 35220716 PMCID: PMC8905934 DOI: 10.1021/acsinfecdis.1c00546] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Indexed: 02/07/2023]
Abstract
Recent times have experienced more than ever the impact of viral infections in humans. Viral infections are known to cause diseases not only in humans but also in plants and animals. Here, we have compiled the literature review of aptamers selected and used for detection and inhibition of viral infections in all three categories: humans, animals, and plants. This review gives an in-depth introduction to aptamers, different types of aptamer selection (SELEX) methodologies, the benefits of using aptamers over commonly used antibody-based strategies, and the structural and functional mechanism of aptasensors for viral detection and therapy. The review is organized based on the different characterization and read-out tools used to detect virus-aptasensor interactions with a detailed index of existing virus-targeting aptamers. Along with addressing recent developments, we also discuss a way forward with aptamers for DNA nanotechnology-based detection and treatment of viral diseases. Overall, this review will serve as a comprehensive resource for aptamer-based strategies in viral diagnostics and treatment.
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Affiliation(s)
- Banani Chakraborty
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Sreyashi Das
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, Uttar Pradesh 208016, India
| | - Arushi Gupta
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Yanyu Xiong
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Nick Holonyak Jr. Micro and Nanotechnology Laboratory (HMNTL), University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - T-V Vyshnavi
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Megan E. Kizer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Jinwei Duan
- Department of Chemistry and Materials Science, Chang’an University, Xi’an, Shaanxi 710064, China
| | - Arun Richard Chandrasekaran
- The RNA Institute, University at Albany, State University of New York, Albany, New York 12222, United States
| | - Xing Wang
- Nick Holonyak Jr. Micro and Nanotechnology Laboratory (HMNTL), University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Carl R. Woese Institute for Genomic Biology (IGB), University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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4
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Serumula W, Fernandez G, Gonzalez VM, Parboosing R. Anti-HIV Aptamers: Challenges and Prospects. Curr HIV Res 2022; 20:7-19. [PMID: 34503417 DOI: 10.2174/1570162x19666210908114825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 08/06/2021] [Accepted: 08/11/2021] [Indexed: 02/08/2023]
Abstract
Human Immunodeficiency Virus (HIV) infection continues to be a significant health burden in many countries around the world. Current HIV treatment through a combination of different antiretroviral drugs (cART) effectively suppresses viral replication, but drug resistance and crossresistance are significant challenges. This has prompted the search for novel targets and agents, such as nucleic acid aptamers. Nucleic acid aptamers are oligonucleotides that attach to the target sites with high affinity and specificity. This review provides a target-by-target account of research into anti-HIV aptamers and summarises the challenges and prospects of this therapeutic strategy, specifically in the unique context of HIV infection.
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Affiliation(s)
- William Serumula
- Department of Virology, National Health Laboratory Service, University of KwaZulu-Natal, c/o Inkosi Albert Luthuli Central Hospital, 5th Floor Laboratory Building, 800 Bellair Road, Mayville, Durban 4091, South Africa
| | - Geronimo Fernandez
- Departamento de Bioquímica-Investigación, Aptus Biotech SL, Avda. Cardenal Herrera Oria, 298-28035 Madrid. Spain
| | - Victor M Gonzalez
- Departamento de Bioquímica-Investigación, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS)-Hospital Ramón y Cajal, 28034 Madrid, Spain
| | - Raveen Parboosing
- Department of Virology, National Health Laboratory Service, University of KwaZulu-Natal, c/o Inkosi Albert Luthuli Central Hospital, 5th Floor Laboratory Building, 800 Bellair Road, Mayville, Durban 4091, South Africa
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Wan Q, Liu X, Zu Y. Oligonucleotide aptamers for pathogen detection and infectious disease control. Theranostics 2021; 11:9133-9161. [PMID: 34522231 PMCID: PMC8419047 DOI: 10.7150/thno.61804] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/04/2021] [Indexed: 12/21/2022] Open
Abstract
During an epidemic or pandemic, the primary task is to rapidly develop precise diagnostic approaches and effective therapeutics. Oligonucleotide aptamer-based pathogen detection assays and control therapeutics are promising, as aptamers that specifically recognize and block pathogens can be quickly developed and produced through simple chemical synthesis. This work reviews common aptamer-based diagnostic techniques for communicable diseases and summarizes currently available aptamers that target various pathogens, including the SARS-CoV-2 virus. Moreover, this review discusses how oligonucleotide aptamers might be leveraged to control pathogen propagation and improve host immune system responses. This review offers a comprehensive data source to the further develop aptamer-based diagnostics and therapeutics specific for infectious diseases.
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Affiliation(s)
| | | | - Youli Zu
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX 77030, USA
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6
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Aptamer Laden Liquid Crystals Biosensing Platform for the Detection of HIV-1 Glycoprotein-120. MOLECULES (BASEL, SWITZERLAND) 2021; 26:molecules26102893. [PMID: 34068186 PMCID: PMC8152991 DOI: 10.3390/molecules26102893] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/06/2021] [Accepted: 05/08/2021] [Indexed: 11/16/2022]
Abstract
We report a label-free and simple approach for the detection of glycoprotein-120 (gp-120) using an aptamer-based liquid crystals (LCs) biosensing platform. The LCs are supported on the surface of a modified glass slide with a suitable amount of B40t77 aptamer, allowing the LCs to be homeotropically aligned. A pronounced topological change was observed on the surface due to a specific interaction between B40t77 and gp-120, which led to the disruption of the homeotropic alignment of LCs. This results in a dark-to-bright transition observed under a polarized optical microscope. With the developed biosensing platform, it was possible to not only identify gp-120, but obtained results were analyzed quantitatively through image analysis. The detection limit of the proposed biosensing platform was investigated to be 0.2 µg/mL of gp-120. Regarding selectivity of the developed platform, no response could be detected when gp-120 was replaced by other proteins, such as bovine serum albumin (BSA), hepatitis A virus capsid protein 1 (Hep A VP1) and immunoglobulin G protein (IgG). Due to attributes such as label-free, high specificity and no need for instrumental read-out, the presented biosensing platform provides the potential to develop a working device for the quick detection of HIV-1 gp-120.
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7
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Kim TH, Lee SW. Aptamers for Anti-Viral Therapeutics and Diagnostics. Int J Mol Sci 2021; 22:ijms22084168. [PMID: 33920628 PMCID: PMC8074132 DOI: 10.3390/ijms22084168] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/13/2021] [Accepted: 04/15/2021] [Indexed: 12/16/2022] Open
Abstract
Viral infections cause a host of fatal diseases and seriously affect every form of life from bacteria to humans. Although most viral infections can receive appropriate treatment thereby limiting damage to life and livelihood with modern medicine and early diagnosis, new types of viral infections are continuously emerging that need to be properly and timely treated. As time is the most important factor in the progress of many deadly viral diseases, early detection becomes of paramount importance for effective treatment. Aptamers are small oligonucleotide molecules made by the systematic evolution of ligands by exponential enrichment (SELEX). Aptamers are characterized by being able to specifically bind to a target, much like antibodies. However, unlike antibodies, aptamers are easily synthesized, modified, and are able to target a wider range of substances, including proteins and carbohydrates. With these advantages in mind, many studies on aptamer-based viral diagnosis and treatments are currently in progress. The use of aptamers for viral diagnosis requires a system that recognizes the binding of viral molecules to aptamers in samples of blood, serum, plasma, or in virus-infected cells. From a therapeutic perspective, aptamers target viral particles or host cell receptors to prevent the interaction between the virus and host cells or target intracellular viral proteins to interrupt the life cycle of the virus within infected cells. In this paper, we review recent attempts to use aptamers for the diagnosis and treatment of various viral infections.
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Affiliation(s)
- Tae-Hyeong Kim
- Department of Molecular Biology, Dankook University, Cheonan 31116, Korea;
| | - Seong-Wook Lee
- Department of Life Convergence, Research Institute of Advanced Omics, Dankook University, Yongin 16890, Korea
- R&D Center, Rznomics Inc., Seongnam 13486, Korea
- Correspondence:
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8
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Panigaj M, Johnson MB, Ke W, McMillan J, Goncharova EA, Chandler M, Afonin KA. Aptamers as Modular Components of Therapeutic Nucleic Acid Nanotechnology. ACS NANO 2019; 13:12301-12321. [PMID: 31664817 PMCID: PMC7382785 DOI: 10.1021/acsnano.9b06522] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Nucleic acids play a central role in all domains of life, either as genetic blueprints or as regulators of various biochemical pathways. The chemical makeup of ribonucleic acid (RNA) or deoxyribonucleic acid (DNA), generally represented by a sequence of four monomers, also provides precise instructions for folding and higher-order assembly of these biopolymers that, in turn, dictate biological functions. The sequence-based specific 3D structures of nucleic acids led to the development of the directed evolution of oligonucleotides, SELEX (systematic evolution of ligands by exponential enrichment), against a chosen target molecule. Among the variety of functions, selected oligonucleotides named aptamers also allow targeting of cell-specific receptors with antibody-like precision and can deliver functional RNAs without a transfection agent. The advancements in the field of customizable nucleic acid nanoparticles (NANPs) opened avenues for the design of nanoassemblies utilizing aptamers for triggering or blocking cell signaling pathways or using aptamer-receptor combinations to activate therapeutic functionalities. A recent selection of fluorescent aptamers enables real-time tracking of NANP formation and interactions. The aptamers are anticipated to contribute to the future development of technologies, enabling an efficient assembly of functional NANPs in mammalian cells or in vivo. These research topics are of top importance for the field of therapeutic nucleic acid nanotechnology with the promises to scale up mass production of NANPs suitable for biomedical applications, to control the intracellular organization of biological materials to enhance the efficiency of biochemical pathways, and to enhance the therapeutic potential of NANP-based therapeutics while minimizing undesired side effects and toxicities.
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Affiliation(s)
- Martin Panigaj
- Nanoscale Science Program, Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
- Institute of Biology and Ecology, Faculty of Science, Pavol Jozef Safarik University in Kosice, Kosice 04154, Slovak Republic
| | - M. Brittany Johnson
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
| | - Weina Ke
- Nanoscale Science Program, Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
| | - Jessica McMillan
- Nanoscale Science Program, Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
| | - Ekaterina A. Goncharova
- Nanoscale Science Program, Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
- Laboratory of Solution Chemistry of Advanced Materials and Technologies, ITMO University, St. Petersburg 191002, Russian Federation
| | - Morgan Chandler
- Nanoscale Science Program, Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
| | - Kirill A. Afonin
- Nanoscale Science Program, Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
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9
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Pan Q, Luo F, Liu M, Zhang XL. Oligonucleotide aptamers: promising and powerful diagnostic and therapeutic tools for infectious diseases. J Infect 2018; 77:83-98. [PMID: 29746951 PMCID: PMC7112547 DOI: 10.1016/j.jinf.2018.04.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 01/02/2018] [Accepted: 04/08/2018] [Indexed: 12/21/2022]
Abstract
The entire human population is at risk of infectious diseases worldwide. Thus far, the diagnosis and treatment of human infectious diseases at the molecular and nanoscale levels have been extremely challenging tasks because of the lack of effective probes to identify and recognize biomarkers of pathogens. Oligonucleotide aptamers are a class of small nucleic acid ligands that are composed of single-stranded DNA (ssDNA) or RNA and act as affinity probes or molecular recognition elements for a variety of targets. These aptamers have an exciting potential for diagnose and/or treatment of specific diseases. In this review, we highlight areas where aptamers have been developed as diagnostic and therapeutic agents for both bacterial and viral infectious diseases as well as aptamer-based detection.
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Affiliation(s)
- Qin Pan
- State Key Laboratory of Virology and Department of Immunology School of Basic Medical Sciences, Medical Research Institute and Hubei Province Key Laboratory of Allergy Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, PR China
| | - Fengling Luo
- State Key Laboratory of Virology and Department of Immunology School of Basic Medical Sciences, Medical Research Institute and Hubei Province Key Laboratory of Allergy Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, PR China
| | - Min Liu
- State Key Laboratory of Virology and Department of Immunology School of Basic Medical Sciences, Medical Research Institute and Hubei Province Key Laboratory of Allergy Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, PR China
| | - Xiao-Lian Zhang
- State Key Laboratory of Virology and Department of Immunology School of Basic Medical Sciences, Medical Research Institute and Hubei Province Key Laboratory of Allergy Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, PR China.
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10
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Bala J, Chinnapaiyan S, Dutta RK, Unwalla H. Aptamers in HIV research diagnosis and therapy. RNA Biol 2018; 15:327-337. [PMID: 29431588 PMCID: PMC5927724 DOI: 10.1080/15476286.2017.1414131] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/07/2017] [Accepted: 12/03/2017] [Indexed: 12/30/2022] Open
Abstract
Aptamers are high affinity single-stranded nucleic acid or protein ligands which exhibit specificity and avidity comparable to, or exceeding that of antibodies and can be generated against most targets. The functionality of aptamers is based on their unique tertiary structure, complexity and their ability to attain unique binding pockets by folding. Aptamers are selected in vitro by a process called Systematic Evolution of Ligands by Exponential enrichment (SELEX). The Kd values for the selected aptamer are often in the picomolar to low nanomolar range. Stable and nontoxic aptamers could be selected for a wide range of ligands including small molecules to large proteins. Aptamers have shown tremendous potential and have found multipurpose application in the field of therapeutic, diagnostic, biosensor and bio-imaging. While their mechanism of action can be similar to that of monoclonal antibodies, aptamers provide additional advantages in terms of production cost, simpler regulatory approval and lower immunogenicity as they are synthesized chemically. Human immunodeficiency virus (HIV) is the primary cause of acquired immune deficiency syndrome (AIDS), which causes significant morbidity and mortality with a significant consequent decrease in the quality of patient's lives. While cART has led to good viral control, people living with HIV now suffer from non-HIV comorbidities due to viral protein expression that cannot be controlled by cART. Hence pathophysiological mechanisms that govern these comorbidities with a focus on therapies that neutralize these HIV effects gained increased attention. Recent advances in HIV/AIDS research have identified several molecular targets and for the development of therapeutic and diagnostic using aptamers against HIV/AIDS. This review presents recent advances in aptamers technology for potential application in HIV diagnostics and therapeutics towards improving the quality of life of people living with HIV.
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Affiliation(s)
- Jyoti Bala
- Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Srinivasan Chinnapaiyan
- Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Rajib Kumar Dutta
- Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Hoshang Unwalla
- Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
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11
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Chiu WK, Brand RM, Camp D, Edick S, Mitchell C, Karas S, Zehmisch A, Ho K, Brand RE, Harrison J, Abo S, Cranston RD, McGowan I. The Safety of Multiple Flexible Sigmoidoscopies with Mucosal Biopsies in Healthy Clinical Trial Participants. AIDS Res Hum Retroviruses 2017; 33:820-826. [PMID: 28296471 PMCID: PMC5564058 DOI: 10.1089/aid.2016.0293] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
During Phase 1 pharmacokinetic/pharmacodynamics studies, participants may undergo multiple sigmoidoscopies, with a collection of 10-20 biopsies during each procedure. This article characterizes the safety of flexible sigmoidoscopies in clinical trial participants. We determined the number of flexible sigmoidoscopies and rectal biopsies that participants underwent and analyzed the frequency, duration, and severity of flexible sigmoidoscopy-related adverse events (AEs). During the study period, 278 participants underwent 1,004 flexible sigmoidoscopies with the collection of 15,930 rectal biopsies. The average number of procedures per participant was 3.6 (median 3; range 1-25), with an average time interval between procedures of 61.8 days (median 28 days; range 1-1,159). There were no serious AEs. Sixteen AEs were related to flexible sigmoidoscopy and occurred in 16 participants, leading to an overall 1.6% (16/1,004) AE rate per procedure and 0.1% (16/15,930) AE rate per biopsy. Of the 16 AEs, 8 (50%) involved abdominal pain, diarrhea, bleeding, flatulence, and bloating, with an average duration of 4.7 days (median 1 day; range 1-28). Most (14/16) AEs were categorized as Grade 1 (mild), whereas two of the AEs were Grade 2 (moderate). No participant withdrew due to procedure-related AEs. Overall, the number of AEs caused by flexible sigmoidoscopy with multiple biopsies was low and the severity was mild, suggesting that this procedure can be safely integrated into protocols requiring repeated intestinal mucosal sampling.
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Affiliation(s)
- Wai Kan Chiu
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Rhonda M. Brand
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
- Department of Dermatology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Danielle Camp
- Magee-Women's Research Institute, Pittsburgh, Pennsylvania
| | - Stacey Edick
- Magee-Women's Research Institute, Pittsburgh, Pennsylvania
| | - Carol Mitchell
- Magee-Women's Research Institute, Pittsburgh, Pennsylvania
| | - Sherri Karas
- Magee-Women's Research Institute, Pittsburgh, Pennsylvania
| | | | - Ken Ho
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Randall E. Brand
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Janet Harrison
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Steven Abo
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Ross D. Cranston
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Ian McGowan
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
- Magee-Women's Research Institute, Pittsburgh, Pennsylvania
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12
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Sharma TK, Bruno JG, Dhiman A. ABCs of DNA aptamer and related assay development. Biotechnol Adv 2017; 35:275-301. [PMID: 28108354 DOI: 10.1016/j.biotechadv.2017.01.003] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 11/19/2016] [Accepted: 01/17/2017] [Indexed: 12/14/2022]
Abstract
This review is intended to guide the novice in aptamer research and development to understand virtually all of the aptamer development options and currently available assay modalities. Aptamer development topics range from discussions of basic and advanced versions of Systematic Evolution of Ligands by EXponential Enrichment (SELEX) and SELEX variations involving incorporation of exotic unnatural nucleotides to expand library diversity for even greater aptamer affinity and specificity to improved next generation methods of DNA sequencing, screening and tracking aptamer development throughout the SELEX process and characterization of lead aptamer candidates. Aptamer assay development topics include descriptions of various colorimetric and fluorescent assays in microplates or on membranes including homogeneous beacon and multiplexed Fluorescence Resonance Energy Transfer (FRET) assays. Finally, a discussion of the potential for marketing successful aptamer-based assays or test kits is included.
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Affiliation(s)
- Tarun Kumar Sharma
- Center for Biodesign and Diagnostics, Translational Health Science and Technology Institute, Faridabad, Haryana 121001, India; AptaBharat Innovation Private Limited, Translational Health Science and Technology Institute Incubator, Haryana 121001, India.
| | - John G Bruno
- Operational Technologies Corporation, 4100 NW Loop 410, Suite, 230, San Antonio, TX 78229, USA..
| | - Abhijeet Dhiman
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi 110029, India.; Faculty of Pharmacy, Uttarakhand Technical University, Dehradun 248007, Uttarakhand, India
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Devnarain N, Ramharack P, Soliman ME. Brain grants permission of access to Zika virus but denies entry to drugs: a molecular modeling perspective to infiltrate the boundary. RSC Adv 2017. [DOI: 10.1039/c7ra05918c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Thein silicodesign of targeted Zika virus inhibitors.
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Affiliation(s)
- Nikita Devnarain
- Molecular Bio-computation and Drug Design Laboratory
- School of Health Sciences
- University of KwaZulu-Natal
- Durban 4001
- South Africa
| | - Pritika Ramharack
- Molecular Bio-computation and Drug Design Laboratory
- School of Health Sciences
- University of KwaZulu-Natal
- Durban 4001
- South Africa
| | - Mahmoud E. Soliman
- Molecular Bio-computation and Drug Design Laboratory
- School of Health Sciences
- University of KwaZulu-Natal
- Durban 4001
- South Africa
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14
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González VM, Martín ME, Fernández G, García-Sacristán A. Use of Aptamers as Diagnostics Tools and Antiviral Agents for Human Viruses. Pharmaceuticals (Basel) 2016; 9:ph9040078. [PMID: 27999271 PMCID: PMC5198053 DOI: 10.3390/ph9040078] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 12/12/2016] [Accepted: 12/13/2016] [Indexed: 02/05/2023] Open
Abstract
Appropriate diagnosis is the key factor for treatment of viral diseases. Time is the most important factor in rapidly developing and epidemiologically dangerous diseases, such as influenza, Ebola and SARS. Chronic viral diseases such as HIV-1 or HCV are asymptomatic or oligosymptomatic and the therapeutic success mainly depends on early detection of the infective agent. Over the last years, aptamer technology has been used in a wide range of diagnostic and therapeutic applications and, concretely, several strategies are currently being explored using aptamers against virus proteins. From a diagnostics point of view, aptamers are being designed as a bio-recognition element in diagnostic systems to detect viral proteins either in the blood (serum or plasma) or into infected cells. Another potential use of aptamers is for therapeutics of viral infections, interfering in the interaction between the virus and the host using aptamers targeting host-cell matrix receptors, or attacking the virus intracellularly, targeting proteins implicated in the viral replication cycle. In this paper, we review how aptamers working against viral proteins are discovered, with a focus on recent advances that improve the aptamers' properties as a real tool for viral infection detection and treatment.
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Affiliation(s)
- Víctor M González
- Departamento de Bioquímica-Investigación, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS)-Hospital Ramón y Cajal, 28034 Madrid, Spain.
| | - M Elena Martín
- Departamento de Bioquímica-Investigación, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS)-Hospital Ramón y Cajal, 28034 Madrid, Spain.
| | - Gerónimo Fernández
- Aptus Biotech SL, c/Faraday, 7, Parque Científico de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain.
| | - Ana García-Sacristán
- Aptus Biotech SL, c/Faraday, 7, Parque Científico de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain.
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15
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Alexandre KB, Mufhandu HT, London GM, Chakauya E, Khati M. Progress and Perspectives on HIV-1 microbicide development. Virology 2016; 497:69-80. [PMID: 27429040 DOI: 10.1016/j.virol.2016.07.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 07/01/2016] [Accepted: 07/04/2016] [Indexed: 12/12/2022]
Abstract
The majority of HIV-1 infections occur via sexual intercourse. Women are the most affected by the epidemic, particularly in developing countries, due to their socio-economic dependence on men and the fact that they are often victims of gender based sexual violence. Despite significant efforts that resulted in the reduction of infection rates in some countries, there is still need for effective prevention methods against the virus. One of these methods for preventing sexual transmission in women is the use of microbicides. In this review we provide a summary of the progress made toward the discovery of affordable and effective HIV-1 microbicides and suggest future directions. We show that there is a wide range of compounds that have been proposed as potential microbicides. Although most of them have so far failed to show protection in humans, there are many promising ones currently in pre-clinical studies and in clinical trials.
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Affiliation(s)
- Kabamba B Alexandre
- Council for Scientific and Industrial Research, Pioneering Health Sciences Laboratory, Biosciences Unit, Pretoria, Gauteng, South Africa.
| | - Hazel T Mufhandu
- Council for Scientific and Industrial Research, Pioneering Health Sciences Laboratory, Biosciences Unit, Pretoria, Gauteng, South Africa
| | - Grace M London
- Department of Health Free State District Health Services and Health Programs, South Africa
| | - E Chakauya
- Council for Scientific and Industrial Research, Pioneering Health Sciences Laboratory, Biosciences Unit, Pretoria, Gauteng, South Africa
| | - M Khati
- Council for Scientific and Industrial Research, Pioneering Health Sciences Laboratory, Biosciences Unit, Pretoria, Gauteng, South Africa; University of Cape Town and Groote Schuur Hospital, Department of Medicine, Cape Town, South Africa
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16
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Fogel R, Limson J. Developing Biosensors in Developing Countries: South Africa as a Case Study. BIOSENSORS-BASEL 2016; 6:bios6010005. [PMID: 26848700 PMCID: PMC4810397 DOI: 10.3390/bios6010005] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 01/23/2016] [Accepted: 01/27/2016] [Indexed: 12/14/2022]
Abstract
A mini-review of the reported biosensor research occurring in South Africa evidences a strong emphasis on electrochemical sensor research, guided by the opportunities this transduction platform holds for low-cost and robust sensing of numerous targets. Many of the reported publications centre on fundamental research into the signal transduction method, using model biorecognition elements, in line with international trends. Other research in this field is spread across several areas including: the application of nanotechnology; the identification and validation of biomarkers; development and testing of biorecognition agents (antibodies and aptamers) and design of electro-catalysts, most notably metallophthalocyanine. Biosensor targets commonly featured were pesticides and metals. Areas of regional import to sub-Saharan Africa, such as HIV/AIDs and tuberculosis diagnosis, are also apparent in a review of the available literature. Irrespective of the targets, the challenge to the effective deployment of such sensors remains shaped by social and economic realities such that the requirements thereof are for low-cost and universally easy to operate devices for field settings. While it is difficult to disentangle the intertwined roles of national policy, grant funding availability and, certainly, of global trends in shaping areas of emphasis in research, most notable is the strong role that nanotechnology, and to a certain extent biotechnology, plays in research regarding biosensor construction. Stronger emphasis on collaboration between scientists in theoretical modelling, nanomaterials application and or relevant stakeholders in the specific field (e.g., food or health monitoring) and researchers in biosensor design may help evolve focused research efforts towards development and deployment of low-cost biosensors.
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Affiliation(s)
- Ronen Fogel
- Biotechnology Innovation Centre, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa.
| | - Janice Limson
- Biotechnology Innovation Centre, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa.
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17
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Davydova A, Vorobjeva M, Pyshnyi D, Altman S, Vlassov V, Venyaminova A. Aptamers against pathogenic microorganisms. Crit Rev Microbiol 2015; 42:847-65. [PMID: 26258445 PMCID: PMC5022137 DOI: 10.3109/1040841x.2015.1070115] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
An important current issue of modern molecular medicine and biotechnology is the search for new approaches to early diagnostic assays and adequate therapy of infectious diseases. One of the promising solutions to this problem might be a development of nucleic acid aptamers capable of interacting specifically with bacteria, protozoa, and viruses. Such aptamers can be used for the specific recognition of infectious agents as well as for blocking of their functions. The present review summarizes various modern SELEX techniques used in this field, and of several currently identified aptamers against viral particles and unicellular organisms, and their applications. The prospects of applying nucleic acid aptamers for the development of novel detection systems and antibacterial and antiviral drugs are discussed.
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Affiliation(s)
- Anna Davydova
- a Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences , Novosibirsk , Russia and
| | - Maria Vorobjeva
- a Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences , Novosibirsk , Russia and
| | - Dmitrii Pyshnyi
- a Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences , Novosibirsk , Russia and
| | - Sidney Altman
- b Department of Molecular, Cellular and Developmental Biology , Yale University , New Haven , CT , USA
| | - Valentin Vlassov
- a Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences , Novosibirsk , Russia and
| | - Alya Venyaminova
- a Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences , Novosibirsk , Russia and
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18
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Ning Y, Cheng L, Ling M, Feng X, Chen L, Wu M, Deng L. Efficient suppression of biofilm formation by a nucleic acid aptamer. Pathog Dis 2015; 73:ftv034. [PMID: 26025307 DOI: 10.1093/femspd/ftv034] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2015] [Indexed: 11/13/2022] Open
Abstract
Biofilms are microbial communities that are attached to a solid surface using extracellular polymeric substances. Motility and initial attachment mediated by flagella are required for biofilm formation. Therefore, blocking the motility of flagella is a potential strategy to inhibit biofilm formation. In this study, single-stranded DNA aptamers specific to the Salmonella choleraesuis were selected after 14 cycles of the systematic evolution of ligands by exponential enrichment. Among the selected aptamers, the aptamer 3 showed the highest affinity for S. choleraesuis with a dissociation constant (Kd) of 41 ± 2 nM. Aptamer 3, conjugated with magnetic beads, was then used to capture its binding target on the bacteria. After mass spectrometry and specific binding analysis, the flagellin was identified as the target captured by aptamer 3. Furthermore, inhibition experiments, inverted microscopy and atomic force microscopy demonstrated that aptamer 3 was able to control the biofilm formation and promote the inhibitory effect of an antibiotic on bacterial biofilms. Single-stranded DNA aptamers therefore have great potential as inhibitors of biofilm formation.
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Affiliation(s)
- Yi Ning
- Department of Microbiology, College of Life Science, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China The Medicine School of Hunan University of Chinese Medicine, Changsha, Hunan 410208, People's Republic of China
| | - Lijuan Cheng
- Department of Microbiology, College of Life Science, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China The Medicine School of Hunan University of Chinese Medicine, Changsha, Hunan 410208, People's Republic of China
| | - Min Ling
- Department of Microbiology, College of Life Science, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China
| | - Xinru Feng
- Department of Microbiology, College of Life Science, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China
| | - Lingli Chen
- The Medicine School of Hunan University of Chinese Medicine, Changsha, Hunan 410208, People's Republic of China
| | - Minxi Wu
- Department of Microbiology, College of Life Science, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China
| | - Le Deng
- Department of Microbiology, College of Life Science, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China
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19
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Aptamers in diagnostics and treatment of viral infections. Viruses 2015; 7:751-80. [PMID: 25690797 PMCID: PMC4353915 DOI: 10.3390/v7020751] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 01/13/2015] [Accepted: 02/12/2015] [Indexed: 02/07/2023] Open
Abstract
Aptamers are in vitro selected DNA or RNA molecules that are capable of binding a wide range of nucleic and non-nucleic acid molecules with high affinity and specificity. They have been conducted through the process known as SELEX (Systematic Evolution of Ligands by Exponential Enrichment). It serves to reach specificity and considerable affinity to target molecules, including those of viral origin, both proteins and nucleic acids. Properties of aptamers allow detecting virus infected cells or viruses themselves and make them competitive to monoclonal antibodies. Specific aptamers can be used to interfere in each stage of the viral replication cycle and also inhibit its penetration into cells. Many current studies have reported possible application of aptamers as a treatment or diagnostic tool in viral infections, e.g., HIV (Human Immunodeficiency Virus), HBV (Hepatitis B Virus), HCV (Hepatitis C Virus), SARS (Severe Acute Respiratory Syndrome), H5N1 avian influenza and recently spread Ebola. This review presents current developments of using aptamers in the diagnostics and treatment of viral diseases.
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20
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Takahashi M, Burnett JC, Rossi JJ. Aptamer–siRNA Chimeras for HIV. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 848:211-34. [DOI: 10.1007/978-1-4939-2432-5_11] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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21
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Lopes de Campos WR, Chirwa N, London G, Rotherham LS, Morris L, Mayosi BM, Khati M. HIV-1 subtype C unproductively infects human cardiomyocytes in vitro and induces apoptosis mitigated by an anti-Gp120 aptamer. PLoS One 2014; 9:e110930. [PMID: 25329893 PMCID: PMC4201581 DOI: 10.1371/journal.pone.0110930] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 09/26/2014] [Indexed: 02/07/2023] Open
Abstract
HIV-associated cardiomyopathy (HIVCM) is of clinical concern in developing countries because of a high HIV-1 prevalence, especially subtype C, and limited access to highly active antiretroviral therapy (HAART). For these reasons, we investigated the direct and indirect effects of HIV-1 subtype C infection of cultured human cardiomyocytes and the mechanisms leading to cardiomyocytes damage; as well as a way to mitigate the damage. We evaluated a novel approach to mitigate HIVCM using a previously reported gp120 binding and HIV-1 neutralizing aptamer called UCLA1. We established a cell-based model of HIVCM by infecting human cardiomyocytes with cell-free HIV-1 or co-culturing human cardiomyocytes with HIV-infected monocyte derived macrophages (MDM). We discovered that HIV-1 subtype C unproductively (i.e. its life cycle is arrested after reverse transcription) infects cardiomyocytes. Furthermore, we found that HIV-1 initiates apoptosis of cardiomyocytes through caspase-9 activation, preferentially via the intrinsic or mitochondrial initiated pathway. CXCR4 receptor-using viruses were stronger inducers of apoptosis than CCR5 utilizing variants. Importantly, we discovered that HIV-1 induced apoptosis of cardiomyocytes was mitigated by UCLA1. However, UCLA1 had no protective effective on cardiomyocytes when apoptosis was triggered by HIV-infected MDM. When HIV-1 was treated with UCLA1 prior to infection of MDM, it failed to induce apoptosis of cardiomyocytes. These data suggest that HIV-1 causes a mitochondrial initiated apoptotic cascade, which signal through caspase-9, whereas HIV-1 infected MDM causes apoptosis predominantly via the death-receptor pathway, mediated by caspase-8. Furthermore the data suggest that UCLA1 protects cardiomyocytes from caspase-mediated apoptosis, directly by binding to HIV-1 and indirectly by preventing infection of MDM.
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Affiliation(s)
- Walter R. Lopes de Campos
- Emerging Health Technologies Competency Area, Biosciences Unit, Council for Scientific and Industrial Research, Pretoria, South Africa
| | - Nthato Chirwa
- Emerging Health Technologies Competency Area, Biosciences Unit, Council for Scientific and Industrial Research, Pretoria, South Africa
| | - Grace London
- Emerging Health Technologies Competency Area, Biosciences Unit, Council for Scientific and Industrial Research, Pretoria, South Africa
| | - Lia S. Rotherham
- Emerging Health Technologies Competency Area, Biosciences Unit, Council for Scientific and Industrial Research, Pretoria, South Africa
| | - Lynn Morris
- National Institute for Communicable Diseases, Sandringham, South Africa
| | - Bongani M. Mayosi
- Department of Medicine, Groote Schuur Hospital and University of Cape Town, Cape Town, South Africa
| | - Makobetsa Khati
- Emerging Health Technologies Competency Area, Biosciences Unit, Council for Scientific and Industrial Research, Pretoria, South Africa
- Department of Medicine, Groote Schuur Hospital and University of Cape Town, Cape Town, South Africa
- * E-mail:
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22
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Zhou J, Rossi J. Cell-type-specific aptamer and aptamer-small interfering RNA conjugates for targeted human immunodeficiency virus type 1 therapy. J Investig Med 2014; 62:914-9. [PMID: 25118114 PMCID: PMC4172518 DOI: 10.1097/jim.0000000000000103] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Human immunodeficiency virus (HIV) is a virus that causes acquired immunodeficiency syndrome, a chronic and incurable disease of the human immune system. As the standard of care for the patients with HIV-1, current highly active antiretroviral treatment has been therapeutically effective in most patients; however, it is not curative, and highly active antiretroviral treatment is intolerable because of severe adverse effects. Therefore, nucleic acid-based therapeutics, such as antisense oligonucleotide, ribozyme, messenger RNA, RNA interference (RNAi)-based therapeutics, aptamer, and so on, have been actively developed as alternative or adjuvant agents for those chemical antiviral drugs to surmount those drawbacks. The combinatorial use of various antiviral nucleic acids could be more efficacious in blocking viral replication and preventing the emergence of resistant variants. In this regard, RNAi can function as a gene-specific therapeutic option for controlling HIV-1 replication. Another type of therapeutic nucleic acid--aptamers--shows promise as a new and potent class of anti-HIV agent and can additionally function as a cell-type-specific delivery vehicle for targeted RNAi. The combined use of small interfering RNA (siRNAs) and aptamers could effectively block viral replication and prevent the emergence of resistant variants. The present review offers a brief overview of the use of cell-type-specific aptamer and aptamer-siRNA conjugates' development in our group for the treatment of HIV-1. Their potentials for targeted delivering RNAi therapeutics (eg, siRNA) and suppressing HIV-1 replication in vitro and in humanized animal model will be highlighted here.
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Affiliation(s)
- Jiehua Zhou
- Department of Molecular and Cellular Biology, Beckman Research Institute of City of Hope, 1500 E. Duarte Road, Duarte, CA 91010
| | - John Rossi
- Department of Molecular and Cellular Biology, Beckman Research Institute of City of Hope, 1500 E. Duarte Road, Duarte, CA 91010
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of City of Hope, 1500 E. Duarte Road, Duarte, CA 91010
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23
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Ngundi MM, Kulagina NV, Anderson GP, Taitt CR. Nonantibody-based recognition: alternative molecules for detection of pathogens. Expert Rev Proteomics 2014; 3:511-24. [PMID: 17078765 DOI: 10.1586/14789450.3.5.511] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Immunoassays have been well established for many years as the cornerstone of detection technologies. These assays are sensitive, selective and, in general, highly resistant to interference from complex sample matrices when compared with nucleic acid-based tests. However, both antibody- and nucleic acid-based detection systems require a priori knowledge of the target and development of specific reagents; multiplexed assays can become increasingly problematic when attempting to detect a plethora of different targets, the identities of which are unknown. In an effort to circumvent many of the limitations inherent in these conventional assays, other recognition reagents are being explored as alternatives, or indeed as adjuncts, to antibodies for pathogen and toxin detection. This article will review a number of different recognition systems ranging in complexity from small molecules, such as nucleic-acid aptamers, carbohydrates and peptides, to systems as highly complicated as whole cells and organisms. All of these alternative systems have tremendous potential to achieve superior sensitivity, selectivity, and stability, but are also subject to their own limitations, which are also discussed. In short, while in its infancy, this field holds great promise for the development of rapid, fieldable assays that are highly complementary to existing antibody- and nucleic acid-based technologies.
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Affiliation(s)
- Miriam M Ngundi
- US Food and Drug Administration, N29 RM418 HFM-434 8800 Rockville Pike, Bethesda, MD 20892, USA.
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24
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Aptamer-based therapeutics: new approaches to combat human viral diseases. Pharmaceuticals (Basel) 2013; 6:1507-42. [PMID: 24287493 PMCID: PMC3873675 DOI: 10.3390/ph6121507] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 11/12/2013] [Accepted: 11/15/2013] [Indexed: 12/18/2022] Open
Abstract
Viruses replicate inside the cells of an organism and continuously evolve to contend with an ever-changing environment. Many life-threatening diseases, such as AIDS, SARS, hepatitis and some cancers, are caused by viruses. Because viruses have small genome sizes and high mutability, there is currently a lack of and an urgent need for effective treatment for many viral pathogens. One approach that has recently received much attention is aptamer-based therapeutics. Aptamer technology has high target specificity and versatility, i.e., any viral proteins could potentially be targeted. Consequently, new aptamer-based therapeutics have the potential to lead a revolution in the development of anti-infective drugs. Additionally, aptamers can potentially bind any targets and any pathogen that is theoretically amenable to rapid targeting, making aptamers invaluable tools for treating a wide range of diseases. This review will provide a broad, comprehensive overview of viral therapies that use aptamers. The aptamer selection process will be described, followed by an explanation of the potential for treating virus infection by aptamers. Recent progress and prospective use of aptamers against a large variety of human viruses, such as HIV-1, HCV, HBV, SCoV, Rabies virus, HPV, HSV and influenza virus, with particular focus on clinical development of aptamers will also be described. Finally, we will discuss the challenges of advancing antiviral aptamer therapeutics and prospects for future success.
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25
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Stabilizing exposure of conserved epitopes by structure guided insertion of disulfide bond in HIV-1 envelope glycoprotein. PLoS One 2013; 8:e76139. [PMID: 24146829 PMCID: PMC3797752 DOI: 10.1371/journal.pone.0076139] [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] [Received: 03/18/2013] [Accepted: 08/26/2013] [Indexed: 11/19/2022] Open
Abstract
Entry of HIV-1 into target cells requires binding of the viral envelope glycoprotein (Env) to cellular receptors and subsequent conformational changes that culminates in fusion of viral and target cell membranes. Recent structural information has revealed that these conformational transitions are regulated by three conserved but potentially flexible layers stacked between the receptor-binding domain (gp120) and the fusion arm (gp41) of Env. We hypothesized that artificial insertion of a covalent bond will ‘snap’ Env into a conformation that is less mobile and stably expose conserved sites. Therefore, we analyzed the interface between these gp120 layers (layers 1, 2 and 3) and identified residues that may form disulfide bonds when substituted with cysteines. We subsequently probed the structures of the resultant mutant gp120 proteins by assaying their binding to a variety of ligands using Surface Plasmon Resonance (SPR) assay. We found that a single disulfide bond strategically inserted between the highly conserved layers 1 and 2 (C65-C115) is able to ‘lock’ gp120 in a CD4 receptor bound conformation (in the absence of CD4), as indicated by the lower dissociation constant (Kd) for the CD4-induced (CD4i) epitope binding 17b antibody. When disulfide-stabilized monomeric (gp120) and trimeric (gp140) Envs were used to immunize rabbits, they were found to elicit a higher proportion of antibodies directed against both CD4i and CD4 binding site epitopes than the wild-type proteins. These results demonstrate that structure-guided stabilization of inter-layer interactions within HIV-1 Env can be used to expose conserved epitopes and potentially overcome the sequence diversity of these molecules.
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26
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Rusnati M, Chiodelli P, Bugatti A, Urbinati C. Bridging the past and the future of virology: surface plasmon resonance as a powerful tool to investigate virus/host interactions. Crit Rev Microbiol 2013; 41:238-60. [PMID: 24059853 DOI: 10.3109/1040841x.2013.826177] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Despite decades of antiviral drug research and development, viruses still remain a top global healthcare problem. Compared to eukaryotic cells, viruses are composed by a limited numbers of proteins that, nevertheless, set up multiple interactions with cellular components, allowing the virus to take control of the infected cell. Each virus/host interaction can be considered as a therapeutical target for new antiviral drugs but, unfortunately, the systematic study of a so huge number of interactions is time-consuming and expensive, calling for models overcoming these drawbacks. Surface plasmon resonance (SPR) is a label-free optical technique to study biomolecular interactions in real time by detecting reflected light from a prism-gold film interface. Launched 20 years ago, SPR has become a nearly irreplaceable technology for the study of biomolecular interactions. Accordingly, SPR is increasingly used in the field of virology, spanning from the study of biological interactions to the identification of putative antiviral drugs. From the literature available, SPR emerges as an ideal link between conventional biological experimentation and system biology studies functional to the identification of highly connected viral or host proteins that act as nodal points in virus life cycle and thus considerable as therapeutical targets for the development of innovative antiviral strategies.
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Affiliation(s)
- Marco Rusnati
- Department of Molecular and Translational Medicine, University of Brescia , Brescia , Italy
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27
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Banerjee J, Nilsen-Hamilton M. Aptamers: multifunctional molecules for biomedical research. J Mol Med (Berl) 2013; 91:1333-42. [PMID: 24045702 DOI: 10.1007/s00109-013-1085-2] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 08/14/2013] [Accepted: 09/04/2013] [Indexed: 12/28/2022]
Abstract
Aptamers are single-stranded oligonucleotides that fold into well-defined three-dimensional shapes, allowing them to bind their targets with high affinity and specificity. They can be generated through an in vitro process called "Systemic Evolution of Ligands by Exponential Enrichment" and applied for specific detection, inhibition, and characterization of various targets like small organic and inorganic molecules, proteins, and whole cells. Aptamers have also been called chemical antibodies because of their synthetic origin and their similar modes of action to antibodies. They exhibit significant advantages over antibodies in terms of their small size, synthetic accessibility, and ability to be chemically modified and thus endowed with new properties. The first generation of aptamer drug "Macugen" was available for public use within 25 years of the discovery of aptamers. With others in the pipeline for clinical trials, this emerging field of medical biotechnology is raising significant interest. However, aptamers pose different problems for their development than for antibodies that need to be addressed to achieve practical applications. It is likely that current developments in aptamer engineering will be the basis for the evolution of improved future bioanalytical and biomedical applications. The present review discusses the development of aptamers for therapeutics, drug delivery, target validation and imaging, and reviews some of the challenges to fully realizing the promise of aptamers in biomedical applications.
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Affiliation(s)
- Jayeeta Banerjee
- Biology Department, Indian Institute of Science Education and Research (IISER), 900 NCL Innovation Park, Dr. Homi Bhabha Road, Pune, 411008, India,
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28
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Zimbres FM, Tárnok A, Ulrich H, Wrenger C. Aptamers: novel molecules as diagnostic markers in bacterial and viral infections? BIOMED RESEARCH INTERNATIONAL 2013; 2013:731516. [PMID: 24083239 PMCID: PMC3780515 DOI: 10.1155/2013/731516] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 07/30/2013] [Indexed: 01/01/2023]
Abstract
Worldwide the entire human population is at risk of infectious diseases of which a high degree is caused by pathogenic protozoans, worms, bacteria, and virus infections. Moreover the current medications against pathogenic agents are losing their efficacy due to increasing and even further spreading drug resistance. Therefore, there is an urgent need to discover novel diagnostic as well as therapeutic tools against infectious agents. In view of that, the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) represents a powerful technology to target selectively pathogenic factors as well as entire bacteria or viruses. SELEX uses a large combinatorial oligonucleic acid library (DNA or RNA) which is processed a by high-flux in vitro screen of iterative cycles. The selected ligands, termed aptamers, are characterized by high specificity and affinity to their target molecule, which are already exploited in diagnostic and therapeutic applications. In this minireview we will discuss the current status of the SELEX technique applied on bacterial and viral pathogens.
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Affiliation(s)
- Flávia M. Zimbres
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Science, University of São Paulo, Avenida Professor Lineu Prestes 1374, 05508-000 São Paulo, SP, Brazil
| | - Attila Tárnok
- Department of Pediatric Cardiology, Heart Centre Leipzig, Translational Centre for Regenerative Medicine (TRM), University of Leipzig, Strümpellstraße 39, 04289 Leipzig, Germany
| | - Henning Ulrich
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes 748, 05508-900 São Paulo, SP, Brazil
| | - Carsten Wrenger
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Science, University of São Paulo, Avenida Professor Lineu Prestes 1374, 05508-000 São Paulo, SP, Brazil
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29
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Ray P, Viles KD, Soule EE, Woodruff RS. Application of aptamers for targeted therapeutics. Arch Immunol Ther Exp (Warsz) 2013; 61:255-71. [PMID: 23563807 DOI: 10.1007/s00005-013-0227-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 03/25/2013] [Indexed: 12/30/2022]
Abstract
Aptamers are short, single-stranded oligonucleotides that are isolated through a process termed systematic evolution of ligands by exponential enrichment. With the advent of cell-based selection technology, aptamers can be selected to bind protein targets that are expressed on the cell surface. These aptamers demonstrate excellent specificity and high affinity toward their target proteins and are often internalized upon binding to their targets. This has opened up the possibility of using aptamers for cell-specific targeted drug delivery. In this review, we will discuss cell-surface protein targets, the aptamers that bind them, and their applications for targeted therapeutics.
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Affiliation(s)
- Partha Ray
- Department of Surgery, Duke University Medical Center, DUMC Box 103035, Durham, NC 27710, USA.
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30
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UCLA1, a synthetic derivative of a gp120 RNA aptamer, inhibits entry of human immunodeficiency virus type 1 subtype C. J Virol 2012; 86:4989-99. [PMID: 22379083 DOI: 10.1128/jvi.06893-11] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Entry of human immunodeficiency virus type 1 (HIV-1) into cells is mediated by the virion surface envelope (Env) glycoproteins, making it a desirable target for antiretroviral entry inhibitors. We previously isolated a family of gp120 binding RNA aptamers and showed that they neutralized the infectivity of HIV-1. In this study, we assessed the activity of a shortened synthetic derivative of the B40 aptamer, called UCLA1, against a large panel of HIV-1 subtype C viruses. UCLA1 tightly bound to a consensus HIV-1 subtype C gp120 and neutralized isolates of the same subtype with 50% inhibitory concentrations (IC(50)s) in the nanomolar range. The aptamer had little toxicity in tests with cell lines and primary cells. Furthermore, it exhibited high therapeutic indices, suggesting that it may be effective at very low doses. Mapping of UCLA1 binding sites on gp120 revealed eight amino acid residues that modulated neutralization resistance. This included residues within the coreceptor binding site, at the base of the V3 loop, and in the bridging sheet within the conserved V1/V2 stem-loop of gp120. The aptamer was also shown to have synergistic effects with T20, a gp41 fusion inhibitor, and IgG1b12 (b12), an anti-CD4 binding site monoclonal antibody. These results suggest that UCLA1 may be suitable for development as a potent HIV-1 entry inhibitor.
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31
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Dey AK, Burke B, Sun Y, Hartog K, Heeney JL, Montefiori D, Srivastava IK, Barnett SW. Use of a polyanionic carbomer, Carbopol971P, in combination with MF59, improves antibody responses to HIV-1 envelope glycoprotein. Vaccine 2012; 30:2749-59. [PMID: 22366638 DOI: 10.1016/j.vaccine.2012.02.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2011] [Revised: 02/09/2012] [Accepted: 02/11/2012] [Indexed: 12/20/2022]
Abstract
Identification of optimal antigen(s) and adjuvant combination(s) to elicit potent, protective, and long-lasting immunity has been a major challenge for the development of effective vaccines against chronic viral pathogens, such as HIV-1, for which there are not yet any licensed vaccines. Here we describe the use of a novel adjuvant approach employing Carbopol 971P(®) NF (hereafter referred to as Carbopol971P), a cross-linked polyanionic carbomer, in combination with the Novartis proprietary oil-in-water adjuvant, MF59, as a potentially safe and effective adjuvant to augment humoral immune responses to the HIV-1 envelope glycoprotein (Env). Intramuscular immunization of small animals with recombinant Env glycoprotein (gp140) formulated in Carbopol971P plus MF59 gave significantly higher titers of binding and virus neutralizing antibodies as compared to immunization using gp140 with either MF59 or Carbopol971P alone. In addition, the antibodies generated were of higher avidity. Importantly, the use of Carbopol971P plus MF59 did not cause any serious adverse reactions or any obvious health problems in animals upon intramuscular administration. Hence, the Carbopol971P plus MF59 adjuvant formulation may provide a benefit for future vaccine applications.
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Affiliation(s)
- Antu K Dey
- Novartis Vaccines & Diagnostics, 45 Sidney Street, Cambridge, MA 02139, USA.
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32
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Binning JM, Leung DW, Amarasinghe GK. Aptamers in virology: recent advances and challenges. Front Microbiol 2012; 3:29. [PMID: 22347221 PMCID: PMC3274758 DOI: 10.3389/fmicb.2012.00029] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 01/17/2012] [Indexed: 01/23/2023] Open
Abstract
Aptamers generated from randomized libraries of nucleic acids have found utility in a wide variety of fields and in the clinic. Aptamers can be used to target both intracellular and extracellular components, including small molecules, proteins, cells, and viruses. With recent technological developments in stringent selection and rapid isolation strategies, it is likely that aptamers will continue to make an impact as useful tools and reagents. Although many recently developed aptamers are intended for use as therapeutic and diagnostic agents, use of aptamers for basic research, including target validation, remains an active area with high potential to impact our understanding of molecular mechanisms and for drug discovery. In this brief review, we will discuss recent aptamer discoveries, their potential role in structural virology, as well as challenges and future prospects.
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Affiliation(s)
- Jennifer M Binning
- Department of Pathology and Immunology, Washington University School of Medicine St. Louis, MO, USA
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33
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Dey AK, Burke B, Sun Y, Sirokman K, Nandi A, Hartog K, Lian Y, Geonnotti AR, Montefiori D, Franti M, Martin G, Carfi A, Kessler P, Martin L, Srivastava IK, Barnett SW. Elicitation of neutralizing antibodies directed against CD4-induced epitope(s) using a CD4 mimetic cross-linked to a HIV-1 envelope glycoprotein. PLoS One 2012; 7:e30233. [PMID: 22291921 PMCID: PMC3265465 DOI: 10.1371/journal.pone.0030233] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 12/12/2011] [Indexed: 11/19/2022] Open
Abstract
The identification of HIV-1 envelope glycoprotein (Env) structures that can generate broadly neutralizing antibodies (BNAbs) is pivotal to the development of a successful vaccine against HIV-1 aimed at eliciting effective humoral immune responses. To that end, the production of novel Env structure(s) that might induce BNAbs by presentation of conserved epitopes, which are otherwise occluded, is critical. Here, we focus on a structure that stabilizes Env in a conformation representative of its primary (CD4) receptor-bound state, thereby exposing highly conserved "CD4 induced" (CD4i) epitope(s) known to be important for co-receptor binding and subsequent virus infection. A CD4-mimetic miniprotein, miniCD4 (M64U1-SH), was produced and covalently complexed to recombinant, trimeric gp140 envelope glycoprotein (gp140) using site-specific disulfide linkages. The resulting gp140-miniCD4 (gp140-S-S-M64U1) complex was recognized by CD4i antibodies and the HIV-1 co-receptor, CCR5. The gp140-miniCD4 complex elicited the highest titers of CD4i binding antibodies as well as enhanced neutralizing antibodies against Tier 1 viruses as compared to gp140 protein alone following immunization of rabbits. Neutralization against HIV-2(7312/V434M) and additional serum mapping confirm the specific elicitation of antibodies directed to the CD4i epitope(s). These results demonstrate the utility of structure-based approach in improving immunogenic response against specific region, such as the CD4i epitope(s) here, and its potential role in vaccine application.
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Affiliation(s)
- Antu K. Dey
- Novartis Vaccines and Diagnostics, Cambridge, Massachusetts, United States of America
| | - Brian Burke
- Novartis Vaccines and Diagnostics, Cambridge, Massachusetts, United States of America
| | - Yide Sun
- Novartis Vaccines and Diagnostics, Cambridge, Massachusetts, United States of America
| | - Klara Sirokman
- Novartis Vaccines and Diagnostics, Cambridge, Massachusetts, United States of America
| | - Avishek Nandi
- Novartis Vaccines and Diagnostics, Cambridge, Massachusetts, United States of America
| | - Karin Hartog
- Novartis Vaccines and Diagnostics, Cambridge, Massachusetts, United States of America
| | - Ying Lian
- Novartis Vaccines and Diagnostics, Cambridge, Massachusetts, United States of America
| | - Anthony R. Geonnotti
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, United States of America
| | - David Montefiori
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Michael Franti
- Novartis Vaccines and Diagnostics, Cambridge, Massachusetts, United States of America
| | - Grégoire Martin
- CEA, iBiTecS, Service d'Ingénierie Moléculaire des Protéines, Gif sur Yvette, France
| | - Andrea Carfi
- Novartis Vaccines and Diagnostics, Cambridge, Massachusetts, United States of America
| | - Pascal Kessler
- CEA, iBiTecS, Service d'Ingénierie Moléculaire des Protéines, Gif sur Yvette, France
| | - Loïc Martin
- CEA, iBiTecS, Service d'Ingénierie Moléculaire des Protéines, Gif sur Yvette, France
| | - Indresh K. Srivastava
- Novartis Vaccines and Diagnostics, Cambridge, Massachusetts, United States of America
| | - Susan W. Barnett
- Novartis Vaccines and Diagnostics, Cambridge, Massachusetts, United States of America
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Meyer C, Hahn U, Rentmeister A. Cell-specific aptamers as emerging therapeutics. J Nucleic Acids 2011; 2011:904750. [PMID: 21904667 PMCID: PMC3166764 DOI: 10.4061/2011/904750] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 06/23/2011] [Indexed: 11/20/2022] Open
Abstract
Aptamers are short nucleic
acids that bind to defined targets with high affinity
and specificity. The first aptamers have been selected
about two decades ago by an in vitro process named
SELEX (systematic evolution of ligands by exponential
enrichment). Since then, numerous aptamers with
specificities for a variety of targets from small
molecules to proteins or even whole cells have been
selected. Their applications range from biosensing and
diagnostics to therapy and target-oriented drug
delivery. More recently, selections using complex
targets such as live cells have become feasible. This
paper summarizes progress in cell-SELEX techniques
and highlights recent developments, particularly in
the field of medically relevant aptamers with a focus
on therapeutic and drug-delivery
applications.
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Affiliation(s)
- Cindy Meyer
- Chemistry Department, MIN Faculty, Institute for Biochemistry and Molecular Biology, Hamburg University, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
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ZHOU J, SHU Y, GUO P, Smith DD, ROSSI JJ. Dual functional RNA nanoparticles containing phi29 motor pRNA and anti-gp120 aptamer for cell-type specific delivery and HIV-1 inhibition. Methods 2011; 54:284-94. [PMID: 21256218 PMCID: PMC3107903 DOI: 10.1016/j.ymeth.2010.12.039] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 12/28/2010] [Accepted: 12/29/2010] [Indexed: 01/06/2023] Open
Abstract
The potent ability of small interfering RNA (siRNA) to inhibit the expression of complementary RNA transcripts is being exploited as a new class of therapeutics for diseases including HIV. However, efficient delivery of siRNAs remains a key obstacle to successful application. A targeted intracellular delivery approach for siRNAs to specific cell types is highly desirable. HIV-1 infection is initiated by the interactions between viral glycoprotein gp120 and cell surface receptor CD4, leading to fusion of the viral membrane with the target cell membrane. Once HIV infects a cell it produces gp120 which is displayed at the cell surface. We previously described a novel dual inhibitory anti-gp120 aptamer-siRNA chimera in which both the aptamer and the siRNA portions have potent anti-HIV activities. We also demonstrated that gp120 can be used for aptamer mediated delivery of anti-HIV siRNAs. Here we report the design, construction and evaluation of chimerical RNA nanoparticles containing a HIV gp120-binding aptamer escorted by the pRNA of bacteriophage phi29 DNA-packaging motor. We demonstrate that pRNA-aptamer chimeras specifically bind to and are internalized into cells expressing HIV gp120. Moreover, the pRNA-aptamer chimeras alone also provide HIV inhibitory function by blocking viral infectivity. The Ab' pRNA-siRNA chimera with 2'-F modified pyrimidines in the sense strand not only improved the RNA stability in serum, but also was functionally processed by Dicer, resulting in specific target gene silencing. Therefore, this dual functional pRNA-aptamer not only represents a potential HIV-1 inhibitor, but also provides a cell-type specific siRNA delivery vehicle, showing promise for systemic anti-HIV therapy.
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Affiliation(s)
- Jiehua ZHOU
- Division of Molecular and Cellular Biology, City of Hope, Duarte, CA
| | - Yi SHU
- Nanobiomedical Center, SEEBME, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Peixuan GUO
- Nanobiomedical Center, SEEBME, University of Cincinnati, Cincinnati, OH 45267, USA
| | - David D. Smith
- Division of Biostatistics, Beckman Research Institute of the City of Hope, Duarte, CA
| | - John J ROSSI
- Division of Molecular and Cellular Biology, City of Hope, Duarte, CA
- Graduate School of Biological Sciences, City of Hope, 1500 East Duarte Rd, Duarte, CA 91010, USA
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Abstract
Nucleic acid aptamers are in vitro-selected small, single-stranded DNA or RNA oligonucleotides that can specifically recognize their target on the basis of their unique 3-dimensional structures. Recent advances in the development of escort aptamers to deliver and enhance the efficacy of other therapeutic agents have drawn enthusiasm in exploiting cell-type-specific aptamers as drug delivery vehicles. This review mainly focuses on the recent developments of aptamer-mediated targeted delivery systems. We also place particular emphasis on aptamers evolved against cell membrane receptors and possibilities for translation to clinical applications.
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Affiliation(s)
- Jiehua Zhou
- Division of Molecular and Cellular Biology, Beckman Research Institute of City of Hope, Duarte, California, USA
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37
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Abstract
The clinical potential of siRNAs for silencing genes critical to disease progression is clear, but a fail-proof method for delivering siRNAs to the cytoplasm of diseased tissues or cells has yet to be identified. A variety of delivery approaches have been explored to directly or indirectly couple siRNAs to delivery vehicles. This review explores the use of synthetic single-stranded DNA and RNA aptamers as a means to deliver siRNAs, shRNAs and antisense oligonucleotides for therapeutic intervention. Topics covered include: the advantages and challenges of using aptamers as delivery tools; current aptamer-mediated siRNA delivery platforms for the treatment of cancer and HIV; and emerging methodologies for the identification of aptamers capable of internalizing into target cell types.
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Affiliation(s)
- Kristina W Thiel
- Department of Internal Medicine, Department of Radiation Oncology, 375 Newton Rd, 5202 MERF, Iowa City, IA 52242, USA
| | - Paloma H Giangrande
- Department of Internal Medicine, Department of Radiation Oncology, 375 Newton Rd, 5202 MERF, Iowa City, IA 52242, USA
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38
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Moore MD, Cookson J, Coventry VK, Sproat B, Rabe L, Cranston RD, McGowan I, James W. Protection of HIV neutralizing aptamers against rectal and vaginal nucleases: implications for RNA-based therapeutics. J Biol Chem 2010; 286:2526-35. [PMID: 21106536 DOI: 10.1074/jbc.m110.178426] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
RNA-based drugs are an emerging class of therapeutics. They have the potential to regulate proteins, chromatin, as well as bind to specific proteins of interest in the form of aptamers. These aptamers are protected from nuclease attack by chemical modifications that enhance their stability for in vivo usage. However, nucleases are ubiquitous, and as we have yet to characterize the entire human microbiome it is likely that many nucleases are yet to be identified. Any novel, unusual enzymes present in vivo might reduce the efficacy of RNA-based therapeutics, even when they are chemically modified. We have previously identified an RNA-based aptamer capable of neutralizing a broad spectrum of clinical HIV-1 isolates and are developing it as a vaginal and rectal microbicide candidate. As a first step we addressed aptamer stability in the milieu of proteins present in these environments. Here we uncover a number of different nucleases that are able to rapidly degrade 2'-F-modified RNA. We demonstrate that the aptamer can be protected from the nuclease(s) present in the vaginal setting, without affecting its antiviral activity, by replacement of key positions with 2'-O-Me-modified nucleotides. Finally, we show that the aptamer can be protected from all nucleases present in both vaginal and rectal compartments using Zn(2+) cations. In conclusion we have derived a stable, antiviral RNA-based aptamer that could form the basis of a pre-exposure microbicide or be a valuable addition to the current tenofovir-based microbicide candidate undergoing clinical trials.
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Affiliation(s)
- Michael D Moore
- Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE, United Kingdom.
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39
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Xu Y, Yang X, Wang E. Review: Aptamers in microfluidic chips. Anal Chim Acta 2010; 683:12-20. [PMID: 21094377 DOI: 10.1016/j.aca.2010.10.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2010] [Revised: 09/13/2010] [Accepted: 10/03/2010] [Indexed: 01/07/2023]
Abstract
This review, covering reports published from 2002 to August 2010, shows how aptamers have made significant contributions in the improvements of microfluidic chips for affinity extraction, separations and detections. Furthermore, microfluidic chip methods for studying aptamer-target interactions and performing aptamer selections have also been summarized. Accordingly, research vacancies and future development trends in these areas are discussed.
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Affiliation(s)
- Yuanhong Xu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Changchun, Jilin 130022, China
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40
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Joubert MK, Kinsley N, Capovilla A, Sewell BT, Jaffer MA, Khati M. A Modeled Structure of an Aptamer−gp120 Complex Provides Insight into the Mechanism of HIV-1 Neutralization. Biochemistry 2010; 49:5880-90. [DOI: 10.1021/bi100301k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Nichole Kinsley
- Elevation Biotech, 8 Blackwood Avenue, Parktown, Johannesburg 2193, South Africa
| | - Alexio Capovilla
- Elevation Biotech, 8 Blackwood Avenue, Parktown, Johannesburg 2193, South Africa
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2193, South Africa
| | - B. Trevor Sewell
- Electron Microscope Unit, University of Cape Town, Rondebosch 7701, South Africa
| | - Mohamed A. Jaffer
- Electron Microscope Unit, University of Cape Town, Rondebosch 7701, South Africa
| | - Makobetsa Khati
- CSIR Biosciences, P.O. Box 395, Pretoria 0001, South Africa
- Department of Medicine, Groote Schuur Hospital and University of Cape Town, Cape Town, South Africa
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41
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Aptamers for Targeted Drug Delivery. Pharmaceuticals (Basel) 2010; 3:1761-1778. [PMID: 27713328 PMCID: PMC4033951 DOI: 10.3390/ph3061761] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 05/19/2010] [Accepted: 05/26/2010] [Indexed: 12/20/2022] Open
Abstract
Aptamers are a class of therapeutic oligonucleotides that form specific three-dimensional structures that are dictated by their sequences. They are typically generated by an iterative screening process of complex nucleic acid libraries employing a process termed Systemic Evolution of Ligands by Exponential Enrichment (SELEX). SELEX has traditionally been performed using purified proteins, and cell surface receptors may be challenging to purify in their properly folded and modified conformations. Therefore, relatively few aptamers have been generated that bind cell surface receptors. However, improvements in recombinant fusion protein technology have increased the availability of receptor extracellular domains as purified protein targets, and the development of cell-based selection techniques has allowed selection against surface proteins in their native configuration on the cell surface. With cell-based selection, a specific protein target is not always chosen, but selection is performed against a target cell type with the goal of letting the aptamer choose the target. Several studies have demonstrated that aptamers that bind cell surface receptors may have functions other than just blocking receptor-ligand interactions. All cell surface proteins cycle intracellularly to some extent, and many surface receptors are actively internalized in response to ligand binding. Therefore, aptamers that bind cell surface receptors have been exploited for the delivery of a variety of cargoes into cells. This review focuses on recent progress and current challenges in the field of aptamer-mediated delivery.
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42
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Zhou J, Rossi JJ. Aptamer-targeted cell-specific RNA interference. SILENCE 2010; 1:4. [PMID: 20226078 PMCID: PMC2835998 DOI: 10.1186/1758-907x-1-4] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Accepted: 02/01/2010] [Indexed: 11/10/2022]
Abstract
This potent ability of small interfering (si)RNAs to inhibit the expression of complementary RNA transcripts is being exploited as a new class of therapeutics for a variety of diseases. However, the efficient and safe delivery of siRNAs into specific cell populations is still the principal challenge in the clinical development of RNAi therapeutics. With the increasing enthusiasm for developing targeted delivery vehicles, nucleic acid-based aptamers targeting cell surface proteins are being explored as promising delivery vehicles to target a distinct disease or tissue in a cell-type-specific manner. The aptamer-based delivery of siRNAs can often enhance the therapeutic efficacy and reduce the unwanted off-target effects of siRNAs. In particular, for RNA interference-based therapeutics, aptamers represent an efficient agent for cell type-specific, systemic delivery of these oligonucleotides. In this review, we summarize recent attractive developments in creatively using cell-internalizing aptamers to deliver siRNAs to target cells. The optimization and improvement of aptamer-targeted siRNAs for clinical translation are further highlighted.
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Affiliation(s)
- Jiehua Zhou
- Division of Molecular and Cellular Biology, Beckman Research Institute of City of Hope, City of Hope, Duarte, CA 91010, USA.
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43
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Thiel KW, Giangrande PH. Therapeutic applications of DNA and RNA aptamers. Oligonucleotides 2009; 19:209-22. [PMID: 19653880 DOI: 10.1089/oli.2009.0199] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Structured single-stranded nucleic acids, or aptamers, bind target molecules with high affinity and specificity, which translates into unique therapeutic possibilities. Currently, aptamers can be identified to most proteins, including blood-clotting factors, cell-surface receptors, and transcription factors. Chemical modifications to the oligonucleotides enhance their pharmacokinetics and pharmacodynamics, thus extending their therapeutic potential. Several aptamers have entered the clinical pipeline for applications and diseases such as macular degeneration, coronary artery bypass graft surgery, and various types of cancer. Furthermore, the functional repertoire of aptamers has expanded with the descriptions of multivalent agonistic aptamers and aptamers-siRNA chimeras. This review highlights those aptamers and aptamer-based approaches with particular likelihood of achieving therapeutic application.
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Affiliation(s)
- Kristina W Thiel
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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44
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Gronewold TMA, Baumgartner A, Hierer J, Sierra S, Blind M, Schäfer F, Blümer J, Tillmann T, Kiwitz A, Kaiser R, Zabe-Kühn M, Quandt E, Famulok M. Kinetic binding analysis of aptamers targeting HIV-1 proteins by a combination of a microbalance array and mass spectrometry (MAMS). J Proteome Res 2009; 8:3568-77. [PMID: 19469583 DOI: 10.1021/pr900265r] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
An enhanced chip-based detection platform was developed by integrating a surface acoustic wave biosensor of the Love-wave type with protein identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS). The system was applied to characterize the interaction of aptamers with their cognate HIV-1 proteins. The aptamers, which target two proteins of HIV-1, were identified using an automated in vitro selection platform. For aptamers S66A-C6 and S68B-C5, which target the V3 loop of the HIV-1 envelope protein gp120, KD values of 406 and 791 nM, respectively, were measured. Aptamer S69A-C15 was shown to bind HIV-1 reverse transcriptase (HIV-1 RT) with a KD value of 637 nM when immobilized on the biosensor surface. HIV-1 RT was identified with high significance using MALDI-ToF MS even in crude protein mixtures. The V3-loop of gp120 could be directly identified when using chip-bound purified protein samples. From crude protein mixtures, it could be identified indirectly with high significance via its fusion-partner glutathione-S-transferase (GST). Our data show that the combination of the selectivity of aptamers with a sensitive detection by MS enables the reliable and quantitative analysis of kinetic binding events of protein solutions in real time.
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45
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Abstract
When aptamers first emerged almost two decades ago, most were RNA species that bound and tagged or inhibited simple target ligands. Very soon after, the 'selectionologists' developing aptamer technology quickly realized more potential for the aptamer. In recent years, advances in aptamer techniques have enabled the use of aptamers as small molecule inhibitors, diagnostic tools and even therapeutics. Aptamers are now being employed in novel applications. We review, herein, some of the recent and exciting applications of aptamers in cell-specific recognition and delivery.
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Affiliation(s)
- Amy C. Yan
- Department of Biochemistry, Albert Einstein College of Medicine, Lab: (718) 678-1025, Office: (718) 678-1024
| | - Matthew Levy
- Department of Biochemistry, Albert Einstein College of Medicine, Lab: (718) 678-1025, Office: (718) 678-1024
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Cytotoxicological analysis of a gp120 binding aptamer with cross-clade human immunodeficiency virus type 1 entry inhibition properties: comparison to conventional antiretrovirals. Antimicrob Agents Chemother 2009; 53:3056-64. [PMID: 19364860 DOI: 10.1128/aac.01502-08] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The long-term cumulative cytotoxicity of antiretrovirals (ARVs) is among the major causes of treatment failure in patients infected with human immunodeficiency virus (HIV) and patients with AIDS. This calls for the development of novel ARVs with less or no cytotoxicity. In the present study, we compared the cytotoxic effects of a cross-clade HIV type 1-neutralizing aptamer called B40 with those of a panel of nonnucleoside reverse transcriptase inhibitors (NNRTIs), nucleoside reverse transcriptase inhibitors (NRTIs), protease inhibitors (PIs), and the entry inhibitor (EI) T20 in human cardiomyocytes and peripheral blood mononuclear cells. An initial screen in which cell death was used as the end-point measurement revealed that the B40 aptamer and T20 were the only test molecules that had insignificant (0.61 < P < 0.92) effects on the viability of both cell types at the maximum concentration used. PIs were the most toxic class (0.001 < P < 0.00001), followed by NNRTIs and NRTIs (0.1 < P < 0.00001). Further studies revealed that B40 and T20 did not interfere with the cellular activity of the cytochrome P450 3A4 enzyme (0.78 < P < 0.24) or monoamine oxidases A and B (0.83 < P < 0.56) when the activities of the enzymes were compared to those in untreated controls of both cell types. Mitochondrion-initiated cellular toxicity is closely associated with the use of ARVs. Therefore, we used real-time PCR to quantify the relative ratio of mitochondrial DNA to nuclear DNA as a marker of toxicity. The levels of mitochondrial DNA remained unchanged in cells exposed to the B40 aptamer compared to the levels in untreated control cells (0.5 > P > 0.06). These data support the development of B40 and related EI aptamers as new ARVs with no cytotoxicity at the estimated potential therapeutic dose.
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Zhou J, Swiderski P, Li H, Zhang J, Neff CP, Akkina R, Rossi JJ. Selection, characterization and application of new RNA HIV gp 120 aptamers for facile delivery of Dicer substrate siRNAs into HIV infected cells. Nucleic Acids Res 2009; 37:3094-109. [PMID: 19304999 PMCID: PMC2685106 DOI: 10.1093/nar/gkp185] [Citation(s) in RCA: 201] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The envelope glycoprotein of human immunodeficiency virus (HIV) consists of an exterior glycoprotein (gp120) and a trans-membrane domain (gp41) and has an important role in viral entry into cells. HIV-1 entry has been validated as a clinically relevant anti-viral strategy for drug discovery. In the present work, several 2'-F substituted RNA aptamers that bind to the HIV-1(BaL) gp120 protein with nanomole affinity were isolated from a RNA library by the SELEX (Systematic Evolution of Ligands by EXponential enrichment) procedure. From two of these aptamers we created a series of new dual inhibitory function anti-gp120 aptamer-siRNA chimeras. The aptamers and aptamer-siRNA chimeras specifically bind to and are internalized into cells expressing HIV gp160. The Dicer-substrate siRNA delivered by the aptamers is functionally processed by Dicer, resulting in specific inhibition of HIV-1 replication and infectivity in cultured CEM T-cells and primary blood mononuclear cells (PBMCs). Moreover, we have introduced a 'sticky' sequence onto a chemically synthesized aptamer which facilitates attachment of the Dicer substrate siRNAs for potential multiplexing. Our results provide a set of novel inhibitory agents for blocking HIV replication and further validate the use of aptamers for delivery of Dicer substrate siRNAs.
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Affiliation(s)
- Jiehua Zhou
- Division of Molecular Biology, Beckman Research Institute of City of Hope, City of Hope, Duarte, CA 91010, USA
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Cohen C, Forzan M, Sproat B, Pantophlet R, McGowan I, Burton D, James W. An aptamer that neutralizes R5 strains of HIV-1 binds to core residues of gp120 in the CCR5 binding site. Virology 2008; 381:46-54. [PMID: 18799178 DOI: 10.1016/j.virol.2008.08.025] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Revised: 06/18/2008] [Accepted: 08/15/2008] [Indexed: 10/21/2022]
Abstract
We have previously isolated nucleic acid ligands (aptamers) that bind the surface envelope glycoprotein, gp120, of HIV-1, and neutralize infection of diverse sub-types of virus. Our earlier studies have identified the overall structure of one of these aptamers, B40, and have indicated that it binds to gp120 in a manner that competes with that of the HIV-1 coreceptor, CCR5, and select "CD4i" antibodies with epitopes overlapping this region. Here, we sought to map the B40 binding site on gp120 more precisely by analysing its interaction with a panel of alanine substitution mutants of gp120. Furthermore, we tested our hypothesis concerning the structure of the 40 nucleotide functional core of the aptamer by the solid-phase synthesis of truncated and chemically modified derivatives. The results confirm our structural predictions and demonstrate that aptamer B40 neutralizes a diverse range of HIV-1 isolates as a result of binding to relatively conserved residues on gp120 at the heart of the CCR5-binding site. These structural insights may provide the basis for the development of potential anti-viral agents with high specificity and robustness.
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Affiliation(s)
- Carla Cohen
- Sir William Dunn School of Pathology, University of Oxford, OX1 3RE, UK.
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Abstract
The successful use of small interfering RNAs (siRNAs) for therapeutic purposes requires safe and efficient delivery to specific cells and tissues. In this study, we demonstrate cell type-specific delivery of anti-human immunodeficiency virus (anti-HIV) siRNAs through fusion to an anti-gp120 aptamer. The envelope glycoprotein is expressed on the surface of HIV-1-infected cells, allowing binding and internalization of the aptamer-siRNA chimeric molecules. We demonstrate that the anti-gp120 aptamer-siRNA chimera is specifically taken up by cells expressing HIV-1 gp120, and that the appended siRNA is processed by Dicer; this releases an anti-tat/rev siRNA which, in turn, inhibits HIV replication. We show for the first time a dual functioning aptamer-siRNA chimera in which both the aptamer and the siRNA portions have potent anti-HIV activities. We also show that gp120 expressed on the surface of HIV-infected cells can be used for aptamer-mediated delivery of anti-HIV siRNAs.
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Abstract
Aptamers constitute a new class of oligonucleotides that have gained therapeutic importance. With the approval of the first aptamer drug, pegaptanib, interest in this class of oligonucleotides, often referred to as 'chemical antibodies', has increased. This article discusses aptamers in relation to other oligonucleotide molecules such as antisense nucleotides, short inhibitory sequences, ribozymes and so on. The development of pegaptanib is looked at from the point of view of the challenges faced in converting aptamers into therapeutic molecules. Cases of other aptamers, which show promise as drugs, are discussed in slightly greater detail. Comparison with antibodies and small molecules, which have hitherto held monopoly in this area, is also made.
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Affiliation(s)
- Gurjot Kaur
- National Institute of Pharmaceutical Education and Research (NIPER), Department of Biotechnology, Sector 67, SAS. Nagar, Punjab 160 062, India.
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