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Brown A, Brill J, Amini R, Nurmi C, Li Y. Development of Better Aptamers: Structured Library Approaches, Selection Methods, and Chemical Modifications. Angew Chem Int Ed Engl 2024; 63:e202318665. [PMID: 38253971 DOI: 10.1002/anie.202318665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/22/2024] [Accepted: 01/22/2024] [Indexed: 01/24/2024]
Abstract
Systematic evolution of ligands by exponential enrichment (SELEX) has been used to discover thousands of aptamers since its development in 1990. Aptamers are short single-stranded oligonucleotides capable of binding to targets with high specificity and selectivity through structural recognition. While aptamers offer advantages over other molecular recognition elements such as their ease of production, smaller size, extended shelf-life, and lower immunogenicity, they have yet to show significant success in real-world applications. By analyzing the importance of structured library designs, reviewing different SELEX methodologies, and the effects of chemical modifications, we provide a comprehensive overview on the production of aptamers for applications in drug delivery systems, therapeutics, diagnostics, and molecular imaging.
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Affiliation(s)
- Alex Brown
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4 K1, Canada
| | - Jake Brill
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4 K1, Canada
| | - Ryan Amini
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4 K1, Canada
| | - Connor Nurmi
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4 K1, Canada
| | - Yingfu Li
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4 K1, Canada
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Wang B, Kobeissy F, Golpich M, Cai G, Li X, Abedi R, Haskins W, Tan W, Benner SA, Wang KKW. Aptamer Technologies in Neuroscience, Neuro-Diagnostics and Neuro-Medicine Development. Molecules 2024; 29:1124. [PMID: 38474636 DOI: 10.3390/molecules29051124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/15/2024] [Accepted: 02/27/2024] [Indexed: 03/14/2024] Open
Abstract
Aptamers developed using in vitro Systematic Evolution of Ligands by Exponential Enrichment (SELEX) technology are single-stranded nucleic acids 10-100 nucleotides in length. Their targets, often with specificity and high affinity, range from ions and small molecules to proteins and other biological molecules as well as larger systems, including cells, tissues, and animals. Aptamers often rival conventional antibodies with improved performance, due to aptamers' unique biophysical and biochemical properties, including small size, synthetic accessibility, facile modification, low production cost, and low immunogenicity. Therefore, there is sustained interest in engineering and adapting aptamers for many applications, including diagnostics and therapeutics. Recently, aptamers have shown promise as early diagnostic biomarkers and in precision medicine for neurodegenerative and neurological diseases. Here, we critically review neuro-targeting aptamers and their potential applications in neuroscience research, neuro-diagnostics, and neuro-medicine. We also discuss challenges that must be overcome, including delivery across the blood-brain barrier, increased affinity, and improved in vivo stability and in vivo pharmacokinetic properties.
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Affiliation(s)
- Bang Wang
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
- The Foundation for Applied Molecular Evolution, 1501 NW 68th Terrace, Gainesville, FL 32605, USA
| | - Firas Kobeissy
- Center for Neurotrauma, MultiOmics and Biomarkers (CNMB), Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
- Department of Emergency Medicine, University of Florida, Gainesville, FL 32611, USA
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Gainesville, FL 32608, USA
- Center for Visual and Neurocognitive Rehabilitation (CVNR), Atlanta VA Health Care System, 1670 Clairmont Rd, Decatur, GA 30033, USA
| | - Mojtaba Golpich
- Center for Neurotrauma, MultiOmics and Biomarkers (CNMB), Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Guangzheng Cai
- Center for Neurotrauma, MultiOmics and Biomarkers (CNMB), Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Xiaowei Li
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Reem Abedi
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut 1107-2020, Lebanon
| | - William Haskins
- Gryphon Bio, Inc., 611 Gateway Blvd. Suite 120 #253, South San Francisco, CA 94080, USA
| | - Weihong Tan
- Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), The Chinese Academy of Sciences, Hangzhou 310022, China
| | - Steven A Benner
- The Foundation for Applied Molecular Evolution, 1501 NW 68th Terrace, Gainesville, FL 32605, USA
| | - Kevin K W Wang
- Center for Neurotrauma, MultiOmics and Biomarkers (CNMB), Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
- Department of Emergency Medicine, University of Florida, Gainesville, FL 32611, USA
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Gainesville, FL 32608, USA
- Center for Visual and Neurocognitive Rehabilitation (CVNR), Atlanta VA Health Care System, 1670 Clairmont Rd, Decatur, GA 30033, USA
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Arese M, Mahmoudian M, Bussolino F. RNA aptamer-mediated gene therapy of prostate cancer: lessons from the past and future directions. Expert Opin Drug Deliv 2023; 20:1609-1621. [PMID: 38058168 DOI: 10.1080/17425247.2023.2292691] [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: 09/22/2023] [Accepted: 12/04/2023] [Indexed: 12/08/2023]
Abstract
INTRODUCTION Prostate cancer (PCa) is one of the most prevalent cancers in the world, and the fifth cause of death from cancer in men. Among the non-surgical treatments for PCa, gene therapy strategies are in the early stages of development and recent clinical trials have provided new insights suggesting promising future. AREAS COVERED Recently, the creation of targeted gene delivery systems, based on specific PCa cell surface markers, has been viewed as a viable therapeutic approach. Prostate-specific membrane antigen (PSMA) is vastly expressed in nearly all prostate malignancies, and the intensity of expression increases with tumor aggressiveness, androgen independence, and metastasis. RNA aptamers are short and single-stranded oligonucleotides, which selectively bind to a specific ligand on the surface of the cells, which makes them fascinating small molecules for target delivery of therapeutics. PSMA-selective RNA aptamers represent great potential for developing targeted-gene delivery tools for PCa. EXPERT OPINION This review provides a thorough horizon for the researchers interested in developing targeted gene delivery systems for PCa via PSMA RNA aptamers. In addition, we provided general information about different prospects of RNA aptamers including discovery approaches, stability, safety, and pharmacokinetics.
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Affiliation(s)
- Marco Arese
- Department of Oncology, University of Torino, Candiolo, Italy
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo, Italy
| | - Mohammad Mahmoudian
- Department of Oncology, University of Torino, Candiolo, Italy
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo, Italy
| | - Federico Bussolino
- Department of Oncology, University of Torino, Candiolo, Italy
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo, Italy
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bioTCIs: Middle-to-Macro Biomolecular Targeted Covalent Inhibitors Possessing Both Semi-Permanent Drug Action and Stringent Target Specificity as Potential Antibody Replacements. Int J Mol Sci 2023; 24:ijms24043525. [PMID: 36834935 PMCID: PMC9968108 DOI: 10.3390/ijms24043525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 01/30/2023] [Accepted: 02/03/2023] [Indexed: 02/12/2023] Open
Abstract
Monoclonal antibody therapies targeting immuno-modulatory targets such as checkpoint proteins, chemokines, and cytokines have made significant impact in several areas, including cancer, inflammatory disease, and infection. However, antibodies are complex biologics with well-known limitations, including high cost for development and production, immunogenicity, a limited shelf-life because of aggregation, denaturation, and fragmentation of the large protein. Drug modalities such as peptides and nucleic acid aptamers showing high-affinity and highly selective interaction with the target protein have been proposed alternatives to therapeutic antibodies. The fundamental limitation of short in vivo half-life has prevented the wide acceptance of these alternatives. Covalent drugs, also known as targeted covalent inhibitors (TCIs), form permanent bonds to target proteins and, in theory, eternally exert the drug action, circumventing the pharmacokinetic limitation of other antibody alternatives. The TCI drug platform, too, has been slow in gaining acceptance because of its potential prolonged side-effect from off-target covalent binding. To avoid the potential risks of irreversible adverse drug effects from off-target conjugation, the TCI modality is broadening from the conventional small molecules to larger biomolecules possessing desirable properties (e.g., hydrolysis resistance, drug-action reversal, unique pharmacokinetics, stringent target specificity, and inhibition of protein-protein interactions). Here, we review the historical development of the TCI made of bio-oligomers/polymers (i.e., peptide-, protein-, or nucleic-acid-type) obtained by rational design and combinatorial screening. The structural optimization of the reactive warheads and incorporation into the targeted biomolecules enabling a highly selective covalent interaction between the TCI and the target protein is discussed. Through this review, we hope to highlight the middle to macro-molecular TCI platform as a realistic replacement for the antibody.
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Development and classification of RNA aptamers for therapeutic purposes: an updated review with emphasis on cancer. Mol Cell Biochem 2022; 478:1573-1598. [DOI: 10.1007/s11010-022-04614-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 11/10/2022] [Indexed: 11/26/2022]
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Oliveira R, Pinho E, Sousa AL, DeStefano JJ, Azevedo NF, Almeida C. Improving aptamer performance with nucleic acid mimics: de novo and post-SELEX approaches. Trends Biotechnol 2021; 40:549-563. [PMID: 34756455 DOI: 10.1016/j.tibtech.2021.09.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 09/29/2021] [Accepted: 09/29/2021] [Indexed: 12/12/2022]
Abstract
Aptamers are structural single-stranded oligonucleotides generated in vitro to bind to a specific target molecule. Aptamers' versatility can be enhanced with nucleic acid mimics (NAMs) during or after a selection process, also known as systematic evolution of ligands by exponential enrichment (SELEX). We address advantages and limitations of the technologies used to generate NAM aptamers, especially the applicability of existing engineered polymerases to replicate NAMs and methodologies to improve aptamers after SELEX. We also discuss the limitations of existing methods for sequencing NAM sequences and bioinformatic tools to predict NAM aptamer structures. As a conclusion, we suggest that NAM aptamers might successfully compete with molecular tools based on proteins such as antibodies for future application.
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Affiliation(s)
- Ricardo Oliveira
- INIAV - National Institute for Agrarian and Veterinarian Research, Rua dos Lagidos, 4485-655 Vairão, Vila do Conde, Portugal; LEPABE - Laboratory for Process Engineering, Environment, Biotechnology, and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Eva Pinho
- INIAV - National Institute for Agrarian and Veterinarian Research, Rua dos Lagidos, 4485-655 Vairão, Vila do Conde, Portugal
| | - Ana Luísa Sousa
- INIAV - National Institute for Agrarian and Veterinarian Research, Rua dos Lagidos, 4485-655 Vairão, Vila do Conde, Portugal; LEPABE - Laboratory for Process Engineering, Environment, Biotechnology, and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Jeffrey J DeStefano
- Cell Biology and Molecular Genetics, Bioscience Research Building, University of Maryland, College Park, MD 20742, USA
| | - Nuno Filipe Azevedo
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology, and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Carina Almeida
- INIAV - National Institute for Agrarian and Veterinarian Research, Rua dos Lagidos, 4485-655 Vairão, Vila do Conde, Portugal; LEPABE - Laboratory for Process Engineering, Environment, Biotechnology, and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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Han J, Gao L, Wang J, Wang J. Application and development of aptamer in cancer: from clinical diagnosis to cancer therapy. J Cancer 2020; 11:6902-6915. [PMID: 33123281 PMCID: PMC7592013 DOI: 10.7150/jca.49532] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/20/2020] [Indexed: 01/04/2023] Open
Abstract
Traditional anticancer therapies can cause serious side effects in clinical treatment due to their nonspecific of tumor cells. Aptamers, also termed as 'chemical antibodies', are short DNA or RNA oligonucleotides selected from the synthetic large random single-strand oligonucleotide library by systematic evolution of ligands by exponential enrichment (SELEX) to bind to lots of different targets, such as proteins or nucleic acid structures. Aptamers have good affinities and high specificity with target molecules, thus may be able to act as drugs themselves to directly inhibit the proliferation of tumor cells, or own great potentialities in the targeted drug delivery systems which can be used in tumor diagnosis and target specific tumor cells, thereby minimizing the toxicity to normal cells. Here we review the unique properties of aptamer represents a great opportunity when applied to the rapidly developing fields of biotechnology and discuss the recent developments in the use of aptamers as powerful tools for analytic, diagnostic and therapeutic applications for cancer.
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Affiliation(s)
- Jing Han
- Department of Reproductive Medicine, Heping Hospital Affiliated to Changzhi Medical College, Changzhi, Shanxi, 046000 China
| | - Liang Gao
- Department of Dermatology, Heji Hospital Affiliated to Changzhi Medical College, Changzhi, Shanxi, 046000 China
| | - Jinsheng Wang
- Department of Pathology, Changzhi Medical College, Changzhi, Shanxi, 046000 China
| | - Jia Wang
- Department of Immunology, Changzhi Medical College, Changzhi, Shanxi, 046000 China
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Chong C, Low C. Synthetic antibody: Prospects in aquaculture biosecurity. FISH & SHELLFISH IMMUNOLOGY 2019; 86:361-367. [PMID: 30502461 DOI: 10.1016/j.fsi.2018.11.060] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/12/2018] [Accepted: 11/27/2018] [Indexed: 06/09/2023]
Abstract
The emerging technology of aptamers that is also known as synthetic antibodies is rivalling antibodies research in the recent years. The unique yet important features of aptamers are advancing antibodies in diverse applications, which include disease diagnosis, prophylactic and therapeutic. The versatility of aptamer has further extended its application to function as gene expression modulator, known as synthetic riboswitches. This report reviewed and discussed the applications of aptamers technology in the biosecurity of aquaculture, the promising developments in biosensor detection for disease diagnosis as well as prophylactic and therapeutic measurements. The application of aptamers technology in immunophenotyping study of aquatic animal is highlighted. Lastly, the future perspective of aptamers in the management of aquatic animal health is discussed, special emphasis on the potential application of aptamers as synthetic riboswitches to enhance host immunity, as well as the growth performance.
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Affiliation(s)
- ChouMin Chong
- Laboratory of Marine Biotechnology, Institute of Bioscience, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor, Malaysia
| | - ChenFei Low
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600, UKM Bangi, Selangor, Malaysia.
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Bayat P, Nosrati R, Alibolandi M, Rafatpanah H, Abnous K, Khedri M, Ramezani M. SELEX methods on the road to protein targeting with nucleic acid aptamers. Biochimie 2018; 154:132-155. [PMID: 30193856 DOI: 10.1016/j.biochi.2018.09.001] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 09/02/2018] [Indexed: 12/14/2022]
Abstract
Systematic evolution of ligand by exponential enrichment (SELEX) is an efficient method used to isolate high-affinity single stranded oligonucleotides from a large random sequence pool. These SELEX-derived oligonucleotides named aptamer, can be selected against a broad spectrum of target molecules including proteins, cells, microorganisms and chemical compounds. Like antibodies, aptamers have a great potential in interacting with and binding to their targets through structural recognition and are therefore called "chemical antibodies". However, aptamers offer advantages over antibodies including smaller size, better tissue penetration, higher thermal stability, lower immunogenicity, easier production, lower cost of synthesis and facilitated conjugation or modification with different functional moieties. Thus, aptamers represent an attractive substitution for protein antibodies in the fields of biomarker discovery, diagnosis, imaging and targeted therapy. Enormous interest in aptamer technology triggered the development of SELEX that has underwent numerous modifications since its introduction in 1990. This review will discuss the recent advances in SELEX methods and their advantages and limitations. Aptamer applications are also briefly outlined in this review.
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Affiliation(s)
- Payam Bayat
- Department of Immunology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Rahim Nosrati
- Cellular and Molecular Research Center, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, Iran; Department of Pharmaceutical Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mona Alibolandi
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Houshang Rafatpanah
- Inflammation and Inflammatory Diseases Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Khalil Abnous
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mostafa Khedri
- Department of Immunology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Ramezani
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.
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Röthlisberger P, Hollenstein M. Aptamer chemistry. Adv Drug Deliv Rev 2018; 134:3-21. [PMID: 29626546 DOI: 10.1016/j.addr.2018.04.007] [Citation(s) in RCA: 215] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/28/2018] [Accepted: 04/03/2018] [Indexed: 12/12/2022]
Abstract
Aptamers are single-stranded DNA or RNA molecules capable of tightly binding to specific targets. These functional nucleic acids are obtained by an in vitro Darwinian evolution method coined SELEX (Systematic Evolution of Ligands by EXponential enrichment). Compared to their proteinaceous counterparts, aptamers offer a number of advantages including a low immunogenicity, a relative ease of large-scale synthesis at affordable costs with little or no batch-to-batch variation, physical stability, and facile chemical modification. These alluring properties have propelled aptamers into the forefront of numerous practical applications such as the development of therapeutic and diagnostic agents as well as the construction of biosensing platforms. However, commercial success of aptamers still proceeds at a weak pace. The main factors responsible for this delay are the susceptibility of aptamers to degradation by nucleases, their rapid renal filtration, suboptimal thermal stability, and the lack of functional group diversity. Here, we describe the different chemical methods available to mitigate these shortcomings. Particularly, we describe the chemical post-SELEX processing of aptamers to include functional groups as well as the inclusion of modified nucleoside triphosphates into the SELEX protocol. These methods will be illustrated with successful examples of chemically modified aptamers used as drug delivery systems, in therapeutic applications, and as biosensing devices.
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Vorobyeva MA, Davydova AS, Vorobjev PE, Pyshnyi DV, Venyaminova AG. Key Aspects of Nucleic Acid Library Design for in Vitro Selection. Int J Mol Sci 2018; 19:E470. [PMID: 29401748 PMCID: PMC5855692 DOI: 10.3390/ijms19020470] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 01/31/2018] [Accepted: 02/02/2018] [Indexed: 02/07/2023] Open
Abstract
Nucleic acid aptamers capable of selectively recognizing their target molecules have nowadays been established as powerful and tunable tools for biospecific applications, be it therapeutics, drug delivery systems or biosensors. It is now generally acknowledged that in vitro selection enables one to generate aptamers to almost any target of interest. However, the success of selection and the affinity of the resulting aptamers depend to a large extent on the nature and design of an initial random nucleic acid library. In this review, we summarize and discuss the most important features of the design of nucleic acid libraries for in vitro selection such as the nature of the library (DNA, RNA or modified nucleotides), the length of a randomized region and the presence of fixed sequences. We also compare and contrast different randomization strategies and consider computer methods of library design and some other aspects.
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Affiliation(s)
- Maria A. Vorobyeva
- Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences, Lavrentiev Ave., 8, 630090 Novosibirsk, Russia; (A.S.D.); (P.E.V.); (D.V.P.); (A.G.V.)
| | - Anna S. Davydova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences, Lavrentiev Ave., 8, 630090 Novosibirsk, Russia; (A.S.D.); (P.E.V.); (D.V.P.); (A.G.V.)
| | - Pavel E. Vorobjev
- Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences, Lavrentiev Ave., 8, 630090 Novosibirsk, Russia; (A.S.D.); (P.E.V.); (D.V.P.); (A.G.V.)
- Department of Natural Sciences, Novosibirsk State University, Pirogova St., 2, 630090 Novosibirsk, Russia
| | - Dmitrii V. Pyshnyi
- Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences, Lavrentiev Ave., 8, 630090 Novosibirsk, Russia; (A.S.D.); (P.E.V.); (D.V.P.); (A.G.V.)
- Department of Natural Sciences, Novosibirsk State University, Pirogova St., 2, 630090 Novosibirsk, Russia
| | - Alya G. Venyaminova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences, Lavrentiev Ave., 8, 630090 Novosibirsk, Russia; (A.S.D.); (P.E.V.); (D.V.P.); (A.G.V.)
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Alshaer W, Ababneh N, Hatmal M, Izmirli H, Choukeife M, Shraim A, Sharar N, Abu-Shiekah A, Odeh F, Al Bawab A, Awidi A, Ismail S. Selection and targeting of EpCAM protein by ssDNA aptamer. PLoS One 2017; 12:e0189558. [PMID: 29245156 PMCID: PMC5731996 DOI: 10.1371/journal.pone.0189558] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/27/2017] [Indexed: 02/07/2023] Open
Abstract
Aptamers are molecules that reveal highly complex and refined molecular recognition properties. These molecules are capable of binding with high affinity and selectivity to targets, ranging from small molecules to whole living cells. Several aptamers have been selected for targeting cellular proteins and they have also used in developing therapeutics and diagnostic strategies. Epithelial cell adhesion molecule (EpCAM) is considered as a cancer stem cell (CSC) biomarker and one of the most promising targets for aptamer selection against CSCs. In this study, we have developed a ssDNA aptamer with high affinity and selectivity of targeting the EpCAM protein extracellular domain. The SELEX technique was applied and the resulted sequences were tested on EpCAM-positive human gastric cancer cell line, KATO III, and the EpCAM-negative mouse embryonic fibroblast, NIH/3T3 cells. Ep1 aptamer was successfully isolated and showed selective binding on EpCAM-positive KATO III cells when compared to EpCAM-negative NIH/3T3 cells, as observed by the flow cytometry and the confocal imaging results. Additionally, the binding of Ep1 to EpCAM protein was assessed using mobility shifting assay and aptamers-protein docking. Furthermore, the binding affinity of Ep1 was measured against EpCAM protein using EpCAM-immobilized on magnetic beads and showed apparent affinity of 118 nM. The results of this study could suggest that Ep1 aptamer can bind specifically to the cellular EpCAM protein, making it an attractive ligand for targeted drug delivery and as an imaging agent for the identification of cancer cells.
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Affiliation(s)
- Walhan Alshaer
- Cell Therapy Center, The University of Jordan, Amman, Jordan
- Molecular Biology Research Laboratory, Faculty of Medicine, University of Jordan, Amma, Jordan
- * E-mail: (WA); (AA)
| | - Nida Ababneh
- Cell Therapy Center, The University of Jordan, Amman, Jordan
- Molecular Biology Research Laboratory, Faculty of Medicine, University of Jordan, Amma, Jordan
| | - Mamon Hatmal
- Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, The Hashemite University, Zarqa, Jordan
| | - Heba Izmirli
- Molecular Biology Research Laboratory, Faculty of Medicine, University of Jordan, Amma, Jordan
| | - Moujab Choukeife
- Molecular Biology Research Laboratory, Faculty of Medicine, University of Jordan, Amma, Jordan
| | - Alaa Shraim
- Molecular Biology Research Laboratory, Faculty of Medicine, University of Jordan, Amma, Jordan
| | - Nour Sharar
- Cell Therapy Center, The University of Jordan, Amman, Jordan
| | - Aya Abu-Shiekah
- Cell Therapy Center, The University of Jordan, Amman, Jordan
| | - Fadwa Odeh
- Department of Chemistry, School of Science, The University of Jordan, Amman, Jordan
| | - Abeer Al Bawab
- Department of Chemistry, School of Science, The University of Jordan, Amman, Jordan
- HMCSR, The University of Jordan, Amman, Jordan
| | - Abdalla Awidi
- Cell Therapy Center, The University of Jordan, Amman, Jordan
- * E-mail: (WA); (AA)
| | - Said Ismail
- Molecular Biology Research Laboratory, Faculty of Medicine, University of Jordan, Amma, Jordan
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Chen C, Zhou S, Cai Y, Tang F. Nucleic acid aptamer application in diagnosis and therapy of colorectal cancer based on cell-SELEX technology. NPJ Precis Oncol 2017; 1:37. [PMID: 29872716 PMCID: PMC5871892 DOI: 10.1038/s41698-017-0041-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 10/17/2017] [Accepted: 10/19/2017] [Indexed: 12/20/2022] Open
Abstract
Nucleic acid aptamers are a class of high-affinity nucleic acid ligands. They serve as “chemical antibodies” since their high affinity and specificity. Nucleic acid aptamers are generated from nucleic acid random-sequence using a systematic evolution of ligands by exponential enrichment (SELEX) technology. SELEX is a process of effectively selecting aptamers from different targets. A newly developed cell-based SELEX technique has been widely used in biomarker discovery, early diagnosis and targeted cancer therapy, particular at colorectal cancer (CRC). Combined with nanostructures, nano-aptamer-drug delivery system was constructed for drug delivery. Various nanostructures functionalized with aptamers are highly efficient and has been used in CRC therapeutic applications. In the present, we introduce a cell- SELEX technique, and summarize the potential application of aptamers as biomarkers in CRC diagnosis and therapy. And some characteristics of aptamer-targeted nanocarriers in CRC have been expatiated. The challenges and perspectives for cell-SELEX are also discussed.
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Affiliation(s)
- Chan Chen
- 1Clinical Laboratory and Medical Research Center, Zhuhai Hospital of Jinan University, Zhuhai People's Hospital, 519000 Zhuhai, Guangdong China
| | - Shan Zhou
- 1Clinical Laboratory and Medical Research Center, Zhuhai Hospital of Jinan University, Zhuhai People's Hospital, 519000 Zhuhai, Guangdong China
| | - Yongqiang Cai
- 1Clinical Laboratory and Medical Research Center, Zhuhai Hospital of Jinan University, Zhuhai People's Hospital, 519000 Zhuhai, Guangdong China
| | - Faqing Tang
- 1Clinical Laboratory and Medical Research Center, Zhuhai Hospital of Jinan University, Zhuhai People's Hospital, 519000 Zhuhai, Guangdong China.,2Clinical Laboratory, Hunan Cancer Hospital & The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, 410006 Changsha, China
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Inomata E, Tashiro E, Miyakawa S, Nakamura Y, Akita K. Alkaline-tolerant RNA aptamers useful to purify acid-sensitive antibodies in neutral conditions. Biochimie 2017; 145:113-124. [PMID: 29104137 DOI: 10.1016/j.biochi.2017.10.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 10/30/2017] [Indexed: 12/20/2022]
Abstract
Recently, several oligonucleotides have been launched for clinical use and a number of therapeutic oligonucleotides are under clinical trials. Aptamer is one of the oligonucleotide therapeutics and has received a lot of attention as a new technology and an efficacious pharmaceutical compound comparable to antibody. Aptamer could be used for various purposes, not only therapeutics but also diagnostics, and applicable to affinity chromatography as a carrier molecule to purify proteins of interest. Here we demonstrate the usage and advantages of RNA aptamer to Fc region of human IgG (i.e., IgG aptamer) for purification of human antibodies. IgG aptamer requires divalent cations for binding to IgG and bound IgG dissociates easily upon treatment with chelating reagent, such as EDTA, under neutral conditions. This elution step is very mild and advantageous for maintaining active conformations of therapeutic antibodies compared to the widely used affinity purification with Protein A/G, which requires acidic elution that often damages the active conformation of antibodies. In fact, of several monoclonal antibodies tested, three antibodies were prone to aggregate on acidic elution from the Protein A/G resin, while remained fully active upon neutral elution from the IgG aptamer resin. The IgG aptamer was fully manipulated to alkaline resistant by ribose 2'-modifications, and thereby reusable numerous times with 1 N NaOH washing. The capacity of the aptamer resin to bind IgG was equivalent to that of the Protein A/G resin. Therefore, the IgG aptamer will provide us with a unique tool to uncover and purify human monoclonal antibodies, which hold therapeutic potential but lose the activity upon acidic elution from Protein A/G-based affinity resin.
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Affiliation(s)
| | | | | | - Yoshikazu Nakamura
- RIBOMIC Inc., Minato-ku, Tokyo 108-0071, Japan; The Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
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15
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Shahdordizadeh M, Taghdisi SM, Sankian M, Ramezani M, Abnous K. Design, isolation and evaluation of the binding efficiency of a DNA aptamer against interleukin 2 receptor alpha, in vitro. Int Immunopharmacol 2017; 53:96-104. [PMID: 29055191 DOI: 10.1016/j.intimp.2017.10.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 10/07/2017] [Accepted: 10/10/2017] [Indexed: 01/19/2023]
Abstract
High levels of CD25, as part of the IL-2 receptor, are expressed on the surface of the activated T lymphocytes and regulatory T cells, indicating that the soluble CD25 (sCD25) could be a clinically valuable tool for treating several diseases. Moreover, progress has been achieved in targeting the IL-2 receptor to treat autoimmune diseases, organ transplantation and certain hematological malignancies. In the current study, generation of an ssDNA aptamer (Apt51) against CD25 is reported. Apt51 bound to CD25 with high affinity (Kd=13.4nM) and specificity. Furthermore, Apt51 was truncated to two shortened variants that almost retained their high affinity for the CD25 protein. Moreover, Apt51 showed good affinity and selectivity for the recognition of CD25 on the cell surface. Importantly, the study showed that Apt51 interfered with the binding of CD25 to its ligand (IL 2) and consequently decreased the IL-2-induced Akt activation.
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Affiliation(s)
- Mahin Shahdordizadeh
- Pharmaceutical Research Center, Advanced Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Pharmaceutical Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Seyed Mohammad Taghdisi
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran; Targeted Drug Delivery Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mojtaba Sankian
- Immunology Research Center, Medical School, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Ramezani
- Pharmaceutical Research Center, Advanced Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Pharmaceutical Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
| | - Khalil Abnous
- Pharmaceutical Research Center, Advanced Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Medicinal Chemistry, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
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16
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17
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Lipi F, Chen S, Chakravarthy M, Rakesh S, Veedu RN. In vitro evolution of chemically-modified nucleic acid aptamers: Pros and cons, and comprehensive selection strategies. RNA Biol 2016; 13:1232-1245. [PMID: 27715478 PMCID: PMC5207382 DOI: 10.1080/15476286.2016.1236173] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Nucleic acid aptamers are single-stranded DNA or RNA oligonucleotide sequences that bind to a specific target molecule with high affinity and specificity through their ability to adopt 3-dimensional structure in solution. Aptamers have huge potential as targeted therapeutics, diagnostics, delivery agents and as biosensors. However, aptamers composed of natural nucleotide monomers are quickly degraded in vivo and show poor pharmacodynamic properties. To overcome this, chemically-modified nucleic acid aptamers are developed by incorporating modified nucleotides after or during the selection process by Systematic Evolution of Ligands by EXponential enrichment (SELEX). This review will discuss the development of chemically-modified aptamers and provide the pros and cons, and new insights on in vitro aptamer selection strategies by using chemically-modified nucleic acid libraries.
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Affiliation(s)
- Farhana Lipi
- a Western Australian Neuroscience Research Institute , Perth , Australia
| | - Suxiang Chen
- a Western Australian Neuroscience Research Institute , Perth , Australia.,b Centre for Comparative Genomics, Murdoch University , Perth , Australia
| | - Madhuri Chakravarthy
- a Western Australian Neuroscience Research Institute , Perth , Australia.,b Centre for Comparative Genomics, Murdoch University , Perth , Australia
| | - Shilpa Rakesh
- a Western Australian Neuroscience Research Institute , Perth , Australia
| | - Rakesh N Veedu
- a Western Australian Neuroscience Research Institute , Perth , Australia.,b Centre for Comparative Genomics, Murdoch University , Perth , Australia
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18
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Urak KT, Shore S, Rockey WM, Chen SJ, McCaffrey AP, Giangrande PH. In vitro RNA SELEX for the generation of chemically-optimized therapeutic RNA drugs. Methods 2016; 103:167-74. [PMID: 26972786 PMCID: PMC4921298 DOI: 10.1016/j.ymeth.2016.03.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 02/22/2016] [Accepted: 03/09/2016] [Indexed: 12/13/2022] Open
Abstract
Aptamers are single-stranded DNA or RNA oligonucleotides that can bind with exquisitely high affinity and specificity to target molecules and are thus often referred to as 'nucleic acid' antibodies. Oligonucleotide aptamers are derived through a process of directed chemical evolution called SELEX (Systematic Evolution of Ligands by Exponential enrichment). This chemical equivalent of Darwinian evolution was first described in 1990 by Tuerk & Gold and Ellington & Szostak and has since yielded aptamers for a wide-range of applications, including biosensor technologies, in vitro diagnostics, biomarker discovery, and therapeutics. Since the inception of the original SELEX method, numerous modifications to the protocol have been described to fit the choice of target, specific conditions or applications. Technologies such as high-throughput sequencing methods and microfluidics have also been adapted for SELEX. In this chapter, we outline key steps in the SELEX process for enabling the rapid identification of RNA aptamers for in vivo applications. Specifically, we provide a detailed protocol for the selection of chemically-optimized RNA aptamers using the original in vitro SELEX methodology. In addition, methods for performing next-generation sequencing of the RNAs from each round of selection, based on Illumina sequencing technology, are discussed.
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Affiliation(s)
- Kevin T Urak
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, United States
| | - Sabrina Shore
- TriLink BioTechnologies Inc., San Diego, CA 92121, United States
| | - William M Rockey
- Department of Radiation Oncology, University of Iowa, Iowa City, IA 52242, United States
| | - Shi-Jie Chen
- Department of Physics, Department of Biochemistry, and Informatics Institute, University of Missouri-Columbia, Columbia, MO 65211, United States
| | | | - Paloma H Giangrande
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, United States; Department of Radiation Oncology, University of Iowa, Iowa City, IA 52242, United States.
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19
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Dellafiore MA, Montserrat JM, Iribarren AM. Modified Nucleoside Triphosphates for In-vitro Selection Techniques. Front Chem 2016; 4:18. [PMID: 27200340 PMCID: PMC4854868 DOI: 10.3389/fchem.2016.00018] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 04/05/2016] [Indexed: 12/22/2022] Open
Abstract
The development of SELEX (Selective Enhancement of Ligands by Exponential Enrichment) provides a powerful tool for the search of functional oligonucleotides with the ability to bind ligands with high affinity and selectivity (aptamers) and for the discovery of nucleic acid sequences with diverse enzymatic activities (ribozymes and DNAzymes). This technique has been extensively applied to the selection of natural DNA or RNA molecules but, in order to improve chemical and structural diversity as well as for particular applications where further chemical or biological stability is necessary, the extension of this strategy to modified oligonucleotides is desirable. Taking into account these needs, this review intends to collect the research carried out during the past years, focusing mainly on the use of modified nucleotides in SELEX and the development of mutant enzymes for broadening nucleoside triphosphates acceptance. In addition, comments regarding the synthesis of modified nucleoside triphosphate will be briefly discussed.
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Affiliation(s)
- María A Dellafiore
- Laboratorio de Química de Ácidos Nucleicos, INGEBI (CONICET) Ciudad Autónoma de Buenos Aires, Argentina
| | - Javier M Montserrat
- Laboratorio de Química de Ácidos Nucleicos, INGEBI (CONICET)Ciudad Autónoma de Buenos Aires, Argentina; Instituto de Ciencias, Universidad Nacional de General SarmientoLos Polvorines, Argentina
| | - Adolfo M Iribarren
- Laboratorio de Química de Ácidos Nucleicos, INGEBI (CONICET)Ciudad Autónoma de Buenos Aires, Argentina; Laboratorio de Biotransformaciones, Universidad Nacional de QuilmesBernal, Argentina
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20
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Aaldering LJ, Tayeb H, Krishnan S, Fletcher S, Wilton SD, Veedu RN. Smart functional nucleic acid chimeras: enabling tissue specific RNA targeting therapy. RNA Biol 2016; 12:412-25. [PMID: 25849197 PMCID: PMC4615226 DOI: 10.1080/15476286.2015.1017234] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
A major obstacle for effective utilization of therapeutic oligonucleotides such as siRNA, antisense, antimiRs etc. is to deliver them specifically to the target tissues. Toward this goal, nucleic acid aptamers are re-emerging as a prominent class of biomolecules capable of delivering target specific therapy and therapeutic monitoring by various molecular imaging modalities. This class of short oligonucleotide ligands with high affinity and specificity are selected from a large nucleic acid pool against a molecular target of choice. Poor cellular uptake of therapeutic oligonucleotides impedes gene-targeting efficacy in vitro and in vivo. In contrast, aptamer-oligonucleotide chimeras have shown the capacity to deliver siRNA, antimiRs, small molecule drugs etc. toward various targets and showed very promising results in various studies on different diseases models. However, to further improve the bio-stability of such chimeric conjugates, it is important to introduce chemically-modified nucleic acid analogs. In this review, we highlight the applications of nucleic acid aptamers for target specific delivery of therapeutic oligonucleotides.
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Affiliation(s)
- Lukas J Aaldering
- a Nucleic Acid Center; Department of Physics, Chemistry and Pharmacy ; University of Southern Denmark ; Odense , Denmark
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21
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Abstract
Advances and applications of synthetic genetic polymers (xeno-nucleic acids) are reviewed in this article. The types of synthetic genetic polymers are summarized. The basic properties of them are elaborated and their technical applications are presented. Challenges and prospects of synthetic genetic polymers are discussed.
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Affiliation(s)
- Qian Ma
- Department of Chemistry
- National University of Singapore
- Singapore 117543
| | - Danence Lee
- Department of Chemistry
- National University of Singapore
- Singapore 117543
| | - Yong Quan Tan
- Department of Biochemistry
- National University of Singapore
- Singapore 117597
| | - Garrett Wong
- Department of Biochemistry
- National University of Singapore
- Singapore 117597
| | - Zhiqiang Gao
- Department of Chemistry
- National University of Singapore
- Singapore 117543
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22
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Vorobyeva M, Timoshenko V, Vorobjev P, Venyaminova A. Aptamers Against Immunologic Targets: Diagnostic and Therapeutic Prospects. Nucleic Acid Ther 2015; 26:52-65. [PMID: 26643948 DOI: 10.1089/nat.2015.0568] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The concept of in vitro selection of nucleic acid aptamers emerged 25 years ago, and since then tremendous progress has been achieved in the development of different aptamers and their applications for various bioanalytical and therapeutic purposes. Among other protein targets of aptamers, immune system proteins are of particular interest both as diagnostic markers and therapeutic targets. The present review summarizes up-to-date articles concerning the selection and design of DNA and RNA aptamers against immunologic targets such as antibodies, cytokines, and T-cell and B-cell receptors. We also discuss the prospects of employing aptamers as recognizing modules of diagnostic aptasensors, potential therapeutic candidates for the treatment of autoimmune diseases and cancer, and specific tools for functional studies of immune system proteins.
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Affiliation(s)
- Mariya Vorobyeva
- Institute of Chemical Biology and Fundamental Medicine , Siberian Division of Russian Academy of Sciences, Novosibirsk, Russia
| | - Valentina Timoshenko
- Institute of Chemical Biology and Fundamental Medicine , Siberian Division of Russian Academy of Sciences, Novosibirsk, Russia
| | - Pavel Vorobjev
- Institute of Chemical Biology and Fundamental Medicine , Siberian Division of Russian Academy of Sciences, Novosibirsk, Russia
| | - Alya Venyaminova
- Institute of Chemical Biology and Fundamental Medicine , Siberian Division of Russian Academy of Sciences, Novosibirsk, Russia
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23
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Generation of Aptamers with an Expanded Chemical Repertoire. Molecules 2015; 20:16643-71. [PMID: 26389865 PMCID: PMC6332006 DOI: 10.3390/molecules200916643] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 08/28/2015] [Accepted: 09/01/2015] [Indexed: 01/03/2023] Open
Abstract
The enzymatic co-polymerization of modified nucleoside triphosphates (dN*TPs and N*TPs) is a versatile method for the expansion and exploration of expanded chemical space in SELEX and related combinatorial methods of in vitro selection. This strategy can be exploited to generate aptamers with improved or hitherto unknown properties. In this review, we discuss the nature of the functionalities appended to nucleoside triphosphates and their impact on selection experiments. The properties of the resulting modified aptamers will be described, particularly those integrated in the fields of biomolecular diagnostics, therapeutics, and in the expansion of genetic systems (XNAs).
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24
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Friedman AD, Kim D, Liu R. Highly stable aptamers selected from a 2'-fully modified fGmH RNA library for targeting biomaterials. Biomaterials 2015; 36:110-23. [PMID: 25443790 DOI: 10.1016/j.biomaterials.2014.08.046] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 08/29/2014] [Indexed: 11/26/2022]
Abstract
When developed as targeting ligands for the in vivo delivery of biomaterials to biological systems, RNA aptamers immediately face numerous obstacles, in particular nuclease degradation and post-selection 2' modification. This study aims to develop a novel class of highly stable, 2'-fully modified RNA aptamers that are ideal for the targeted delivery of biomaterials. We demonstrated the facile transcription of a fGmH (2'-F-dG, 2'-OMe-dA/dC/dU) RNA library with unexpected hydrophobicity, the direct selection of aptamers from a fGmH RNA library that bind Staphylococcus aureus Protein A (SpA) as a model target, and the superior nuclease and serum stability of these aptamers compared to 2'-partially modified RNA variants. Characterizations of fGmH RNA aptamers binding to purified SpA and to endogenous SpA present on the surface of S. aureus cells demonstrate fGmH RNA aptamer selectivity and stability. Significantly, fGmH RNA aptamers were able to functionalize, stabilize, and specifically deliver aggregation-prone silver nanoparticles (AgNPs) to S. aureus with SpA-dependent antimicrobial effects. This study describes a novel aptamer class with considerable potential to improve the in vivo applicability of nucleic acid-based affinity molecules to biomaterials.
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25
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McConnell EM, Holahan MR, DeRosa MC. Aptamers as promising molecular recognition elements for diagnostics and therapeutics in the central nervous system. Nucleic Acid Ther 2015; 24:388-404. [PMID: 25296265 DOI: 10.1089/nat.2014.0492] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Oligonucleotide aptamers are short, synthetic, single-stranded DNA or RNA able to recognize and bind to a multitude of targets ranging from small molecules to cells. Aptamers have emerged as valuable tools for fundamental research, clinical diagnosis, and therapy. Due to their small size, strong target affinity, lack of immunogenicity, and ease of chemical modification, aptamers are an attractive alternative to other molecular recognition elements, such as antibodies. Although it is a challenging environment, the central nervous system and related molecular targets present an exciting potential area for aptamer research. Aptamers hold promise for targeted drug delivery, diagnostics, and therapeutics. Here we review recent advances in aptamer research for neurotransmitter and neurotoxin targets, demyelinating disease and spinal cord injury, cerebrovascular disorders, pathologies related to protein aggregation (Alzheimer's, Parkinson's, and prions), brain cancer (glioblastomas and gliomas), and regulation of receptor function. Challenges and limitations posed by the blood brain barrier are described. Future perspectives for the application of aptamers to the central nervous system are also discussed.
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Affiliation(s)
- Erin M McConnell
- 1 Department of Chemistry, Carleton University , Ottawa, Ontario, Canada
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26
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Wu C, Wan S, Hou W, Zhang L, Xu J, Cui C, Wang Y, Hu J, Tan W. A survey of advancements in nucleic acid-based logic gates and computing for applications in biotechnology and biomedicine. Chem Commun (Camb) 2015; 51:3723-34. [PMID: 25597946 PMCID: PMC4442017 DOI: 10.1039/c4cc10047f] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Nucleic acid-based logic devices were first introduced in 1994. Since then, science has seen the emergence of new logic systems for mimicking mathematical functions, diagnosing disease and even imitating biological systems. The unique features of nucleic acids, such as facile and high-throughput synthesis, Watson-Crick complementary base pairing, and predictable structures, together with the aid of programming design, have led to the widespread applications of nucleic acids (NA) for logic gate and computing in biotechnology and biomedicine. In this feature article, the development of in vitro NA logic systems will be discussed, as well as the expansion of such systems using various input molecules for potential cellular, or even in vivo, applications.
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Affiliation(s)
- Cuichen Wu
- Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Shands Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida 32611-7200, United States, , Fax: +1-352-392-4651, Tel: +1-352-846-2410
| | - Shuo Wan
- Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Shands Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida 32611-7200, United States, , Fax: +1-352-392-4651, Tel: +1-352-846-2410
| | - Weijia Hou
- Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Shands Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida 32611-7200, United States, , Fax: +1-352-392-4651, Tel: +1-352-846-2410
| | - Liqin Zhang
- Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Shands Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida 32611-7200, United States, , Fax: +1-352-392-4651, Tel: +1-352-846-2410
| | - Jiehua Xu
- Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Shands Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida 32611-7200, United States, , Fax: +1-352-392-4651, Tel: +1-352-846-2410
- Department of Nuclear Medicine, the third affiliated hospital, Sun Yat-sen University, Guangzhou 510630, P. R. China
| | - Cheng Cui
- Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Shands Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida 32611-7200, United States, , Fax: +1-352-392-4651, Tel: +1-352-846-2410
| | - Yanyue Wang
- Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Shands Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida 32611-7200, United States, , Fax: +1-352-392-4651, Tel: +1-352-846-2410
| | - Jun Hu
- Hunan Tumor Hospital, Changsha 410082, P. R. China
| | - Weihong Tan
- Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Shands Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida 32611-7200, United States, , Fax: +1-352-392-4651, Tel: +1-352-846-2410
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Stovall GM, Bedenbaugh RS, Singh S, Meyer AJ, Hatala PJ, Ellington AD, Hall B. In vitro selection using modified or unnatural nucleotides. ACTA ACUST UNITED AC 2014; 56:9.6.1-33. [PMID: 25606981 DOI: 10.1002/0471142700.nc0906s56] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Incorporation of modified nucleotides into in vitro RNA or DNA selections offers many potential advantages, such as the increased stability of selected nucleic acids against nuclease degradation, improved affinities, expanded chemical functionality, and increased library diversity. This unit provides useful information and protocols for in vitro selection using modified nucleotides. It includes a discussion of when to use modified nucleotides; protocols for evaluating and optimizing transcription reactions, as well as confirming the incorporation of the modified nucleotides; protocols for evaluating modified nucleotide transcripts as template in reverse transcription reactions; protocols for the evaluation of the fidelity of modified nucleotides in the replication and the regeneration of the pool; and a protocol to compare modified nucleotide pools and selection conditions.
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Affiliation(s)
- Gwendolyn M Stovall
- The University of Texas at Austin, Austin, Texas; Altermune Technologies LLC, Austin, Texas
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28
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Ibach J, Dietrich L, Koopmans KRM, Nöbel N, Skoupi M, Brakmann S. Identification of a T7 RNA polymerase variant that permits the enzymatic synthesis of fully 2'-O-methyl-modified RNA. J Biotechnol 2013; 167:287-95. [PMID: 23871655 DOI: 10.1016/j.jbiotec.2013.07.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 07/04/2013] [Accepted: 07/08/2013] [Indexed: 12/11/2022]
Abstract
T7 RNA polymerase is an important biocatalyst that is used in diverse biotechnological applications such as in vitro transcription or protein expression. The enzyme displays high substrate specificity which is payed by significant limitations regarding incorporation of synthetic nucleotide analogs. Of specific interest is enzymatic synthesis of 2'-O-methyl-modified RNA as these nucleic acids exhibit improved biochemical and pharmacokinetic properties that make them attractive for diagnostic and therapeutic purposes. We report here on the development of an activity-based selection/screening approach for assessing polymerase activities in the presence of 2'-O-methyl-modified nucleotides, and on the identification of one variant T7 RNA polymerase which is capable of synthesizing all-2'-O-methyl RNA.
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Affiliation(s)
- Jenny Ibach
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Otto-Hahn-Strasse 11, D-44227 Dortmund, Germany
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29
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Abstract
For over 20 years, laboratories around the world have been applying the principles of Darwinian evolution to isolate DNA and RNA molecules with specific ligand-binding or catalytic activities. This area of synthetic biology, commonly referred to as in vitro genetics, is made possible by the availability of natural polymerases that can replicate genetic information in the laboratory. Moving beyond natural nucleic acids requires organic chemistry to synthesize unnatural analogues and polymerase engineering to create enzymes that recognize artificial substrates. Progress in both of these areas has led to the emerging field of synthetic genetics, which explores the structural and functional properties of synthetic genetic polymers by in vitro evolution. This review examines recent advances in the Darwinian evolution of artificial genetic polymers and their potential downstream applications in exobiology, molecular medicine, and synthetic biology.
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Affiliation(s)
- John C Chaput
- Center for Evolutionary Medicine and Informatics in the Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-5301, USA.
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30
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Kasahara Y, Kuwahara M. Artificial specific binders directly recovered from chemically modified nucleic acid libraries. J Nucleic Acids 2012; 2012:156482. [PMID: 23094139 PMCID: PMC3472525 DOI: 10.1155/2012/156482] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 08/19/2012] [Indexed: 11/18/2022] Open
Abstract
Specific binders comprised of nucleic acids, that is, RNA/DNA aptamers, are attractive functional biopolymers owing to their potential broad application in medicine, food hygiene, environmental analysis, and biological research. Despite the large number of reports on selection of natural DNA/RNA aptamers, there are not many examples of direct screening of chemically modified nucleic acid aptamers. This is because of (i) the inferior efficiency and accuracy of polymerase reactions involving transcription/reverse-transcription of modified nucleotides compared with those of natural nucleotides, (ii) technical difficulties and additional time and effort required when using modified nucleic acid libraries, and (iii) ambiguous efficacies of chemical modifications in binding properties until recently; in contrast, the effects of chemical modifications on biostability are well studied using various nucleotide analogs. Although reports on the direct screening of a modified nucleic acid library remain in the minority, chemical modifications would be essential when further functional expansion of nucleic acid aptamers, in particular for medical and biological uses, is considered. This paper focuses on enzymatic production of chemically modified nucleic acids and their application to random screenings. In addition, recent advances and possible future research are also described.
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Affiliation(s)
- Yuuya Kasahara
- Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu 376-8515, Japan
| | - Masayasu Kuwahara
- Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu 376-8515, Japan
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Rockey WM, Hernandez FJ, Huang SY, Cao S, Howell CA, Thomas GS, Liu XY, Lapteva N, Spencer DM, McNamara JO, Zou X, Chen SJ, Giangrande PH. Rational truncation of an RNA aptamer to prostate-specific membrane antigen using computational structural modeling. Nucleic Acid Ther 2012; 21:299-314. [PMID: 22004414 DOI: 10.1089/nat.2011.0313] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
RNA aptamers represent an emerging class of pharmaceuticals with great potential for targeted cancer diagnostics and therapy. Several RNA aptamers that bind cancer cell-surface antigens with high affinity and specificity have been described. However, their clinical potential has yet to be realized. A significant obstacle to the clinical adoption of RNA aptamers is the high cost of manufacturing long RNA sequences through chemical synthesis. Therapeutic aptamers are often truncated postselection by using a trial-and-error process, which is time consuming and inefficient. Here, we used a "rational truncation" approach guided by RNA structural prediction and protein/RNA docking algorithms that enabled us to substantially truncateA9, an RNA aptamer to prostate-specific membrane antigen (PSMA),with great potential for targeted therapeutics. This truncated PSMA aptamer (A9L; 41mer) retains binding activity, functionality, and is amenable to large-scale chemical synthesis for future clinical applications. In addition, the modeled RNA tertiary structure and protein/RNA docking predictions revealed key nucleotides within the aptamer critical for binding to PSMA and inhibiting its enzymatic activity. Finally, this work highlights the utility of existing RNA structural prediction and protein docking techniques that may be generally applicable to developing RNA aptamers optimized for therapeutic use.
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Affiliation(s)
- William M Rockey
- Department of Radiation Oncology, University of Iowa, Iowa City, USA
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Ni X, Castanares M, Mukherjee A, Lupold SE. Nucleic acid aptamers: clinical applications and promising new horizons. Curr Med Chem 2012; 18:4206-14. [PMID: 21838685 DOI: 10.2174/092986711797189600] [Citation(s) in RCA: 208] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 07/15/2011] [Accepted: 07/17/2011] [Indexed: 12/25/2022]
Abstract
Aptamers are a special class of nucleic acid molecules that are beginning to be investigated for clinical use. These small RNA/DNA molecules can form secondary and tertiary structures capable of specifically binding proteins or other cellular targets; they are essentially a chemical equivalent of antibodies. Aptamers have the advantage of being highly specific, relatively small in size, and non-immunogenic. Since the discovery of aptamers in the early 1990s, great efforts have been made to make them clinically relevant for diseases like cancer, HIV, and macular degeneration. In the last two decades, many aptamers have been clinically developed as inhibitors for targets such as vascular endothelial growth factor (VEGF) and thrombin. The first aptamer based therapeutic was FDA approved in 2004 for the treatment of age-related macular degeneration and several other aptamers are currently being evaluated in clinical trials. With advances in targeted-therapy, imaging, and nanotechnology, aptamers are readily considered as potential targeting ligands because of their chemical synthesis and ease of modification for conjugation. Preclinical studies using aptamer-siRNA chimeras and aptamer targeted nanoparticle therapeutics have been very successful in mouse models of cancer and HIV. In summary aptamers are in several stages of development, from pre-clinical studies to clinical trials and even as FDA approved therapeutics. In this review, we will discuss the current state of aptamers in clinical trials as well as some promising aptamers in pre-clinical development.
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Affiliation(s)
- X Ni
- James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine 600 N Wolfe St., Baltimore, MD 21287, USA
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Lauridsen LH, Rothnagel JA, Veedu RN. Enzymatic recognition of 2'-modified ribonucleoside 5'-triphosphates: towards the evolution of versatile aptamers. Chembiochem 2011; 13:19-25. [PMID: 22162282 DOI: 10.1002/cbic.201100648] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Indexed: 01/21/2023]
Abstract
The quest for effective, selective and nontoxic nucleic-acid-based drugs has led to designing modifications of naturally occurring nucleosides. A number of modified nucleic acids have been made in the past decades in the hope that they would prove useful in target-validation studies and therapeutic applications involving antisense, RNAi, aptamer, and ribozyme-based technologies. Since their invention in the early 1990s, aptamers have emerged as a very promising class of therapeutics, with one drug entering the market for the treatment of age-related macular degeneration. To combat the limitations of aptamers containing naturally occurring nucleotides, chemically modified nucleotides have to be used. In order to apply modified nucleotides in aptamer drug development, their enzyme-recognition capabilities must be understood. For this purpose, several modified nucleoside 5'-triphosphates were synthesized and investigated as substrates for various enzymes. Herein, we review studies on the enzyme-recognition of various 2'-sugar-modified NTPs that were carried out with a view to their effective utilization in SELEX processes to generate versatile aptamers.
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Affiliation(s)
- Lasse H Lauridsen
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
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You M, Chen Y, Peng L, Han D, Yin B, Ye B, Tan W. Engineering DNA aptamers for novel analytical and biomedical applications. Chem Sci 2011. [DOI: 10.1039/c0sc00647e] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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Abstract
Aptamers are nucleic acid sequences synthesized through in vitro selection and amplification technique, possessing a broader range of applications in therapeutics, biosensing, diagnostics, and research. Aptamers offer a number of advantages over their antibodies counterpart, one of them is their ability to undergo chemical derivatization to increase their life in the body fluids and bioavailability in animals. Although aptamers were discovered in 1990s, they have become one of the most widely investigated molecules, with a huge number of publications in the last decade. This article presents an overview of the advancements that have been made in aptamers. We mainly focused on articles published since 2005.
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Affiliation(s)
- Muhammad Ali Syed
- Department of Biosciences, Comsats Institute of Information Technology, Islamabad, Pakistan.
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Abstract
Aptamers are single-stranded oligonucleotides that fold into defined architectures and bind to targets such as proteins. In binding proteins they often inhibit protein–protein interactions and thereby may elicit therapeutic effects such as antagonism. Aptamers are discovered using SELEX (systematic evolution of ligands by exponential enrichment), a directed in vitro evolution technique in which large libraries of degenerate oligonucleotides are iteratively and alternately partitioned for target binding. They are then amplified enzymatically until functional sequences are identified by the sequencing of cloned individuals. For most therapeutic purposes, aptamers are truncated to reduce synthesis costs, modified at the sugars and capped at their termini to increase nuclease resistance, and conjugated to polyethylene glycol or another entity to reduce renal filtration rates. The first aptamer approved for a therapeutic application was pegaptanib sodium (Macugen; Pfizer/Eyetech), which was approved in 2004 by the US Food and Drug Administration for macular degeneration. Eight other aptamers are currently undergoing clinical evaluation for various haematology, oncology, ocular and inflammatory indications. Aptamers are ultimately chemically synthesized in a readily scalable process in which specific conjugation points are introduced with defined stereochemistry. Unlike some protein therapeutics, aptamers do not elicit antibodies, and because aptamers generally contain sugars modified at their 2′-positions, Toll-like receptor-mediated innate immune responses are also abrogated. As aptamers are oligonucleotides they can be readily assembled into supramolecular multi-component structures using hybridization. Owing to the fact that binding to appropriate cell-surface targets can lead to internalization, aptamers can also be used to deliver therapeutic cargoes such as small interfering RNA. Supramolecular assemblies of aptamers and delivery agents have already been demonstrated in vivo and may pave the way for further therapeutic strategies with this modality in the future.
Aptamers are oligonucleotide sequences that are capable of recognizing target proteins with an affinity and specificity rivalling that of antibodies. In this article, Keefe and colleagues discuss the development, properties and therapeutic potential of aptamers, highlighting those currently in the clinic. Nucleic acid aptamers can be selected from pools of random-sequence oligonucleotides to bind a wide range of biomedically relevant proteins with affinities and specificities that are comparable to antibodies. Aptamers exhibit significant advantages relative to protein therapeutics in terms of size, synthetic accessibility and modification by medicinal chemistry. Despite these properties, aptamers have been slow to reach the marketplace, with only one aptamer-based drug receiving approval so far. A series of aptamers currently in development may change how nucleic acid therapeutics are perceived. It is likely that in the future, aptamers will increasingly find use in concert with other therapeutic molecules and modalities.
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Wang Y, Khaing ZZ, Li N, Hall B, Schmidt CE, Ellington AD. Aptamer antagonists of myelin-derived inhibitors promote axon growth. PLoS One 2010; 5:e9726. [PMID: 20300533 PMCID: PMC2838799 DOI: 10.1371/journal.pone.0009726] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Accepted: 02/22/2010] [Indexed: 11/18/2022] Open
Abstract
Myelin of the adult central nervous system (CNS) is one of the major sources of inhibitors of axon regeneration following injury. The three known myelin-derived inhibitors (Nogo, MAG, and OMgp) bind with high affinity to the Nogo-66 receptor (NgR) on axons and limit neurite outgrowth. Here we show that RNA aptamers can be generated that bind with high affinity to NgR, compete with myelin-derived inhibitors for binding to NgR, and promote axon elongation of neurons in vitro even in the presence of these inhibitors. Aptamers may have key advantages over protein antagonists, including low immunogenicity and the possibility of ready modification during chemical synthesis for stability, signaling, or immobilization. This first demonstration that aptamers can directly influence neuronal function suggests that aptamers may prove useful for not only healing spinal cord and other neuronal damage, but may be more generally useful as neuromodulators.
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Affiliation(s)
- Yuxuan Wang
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas, United States of America
| | - Zin Z. Khaing
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, United States of America
| | - Na Li
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas, United States of America
| | - Brad Hall
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas, United States of America
| | - Christine E. Schmidt
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, United States of America
- Department of Chemical Engineering, Cockrell School of Engineering, University of Texas at Austin, Austin, Texas, United States of America
| | - Andrew D. Ellington
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas, United States of America
- * E-mail:
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Abstract
Small molecule drugs are relatively effective in working on 'drugable' targets such as GPCRs, ion channels, kinases, proteases, etc but ineffective at blocking protein-protein interactions that represent an emerging class of 'nondrugable' central nervous system (CNS) targets. This article provides an overview of novel therapeutic modalities such as biologics (in particular antibodies) and emerging oligonucleotide therapeutics such as antisense, small-interfering RNA, and aptamers. Their key properties, overall strengths and limitations, and their utility as tools for target validation are presented. In addition, issues with regard to CNS targets as it relates to the blood-brain barrier penetration are discussed. Finally, examples of their application as therapeutics for the treatment of pain and some neurological disorders such as Alzheimer's disease, multiple sclerosis, Huntington's disease, and Parkinson's disease are provided.
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Keefe AD, Cload ST. SELEX with modified nucleotides. Curr Opin Chem Biol 2008; 12:448-56. [PMID: 18644461 DOI: 10.1016/j.cbpa.2008.06.028] [Citation(s) in RCA: 239] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Revised: 06/09/2008] [Accepted: 06/23/2008] [Indexed: 11/16/2022]
Abstract
Aptamers, a promising new class of therapeutics, are single-stranded oligonucleotides generated via an in vitro selection process that bind to and inhibit the activity of target proteins in a manner similar to therapeutic antibodies. In order to enhance the drug-like character of aptamers, oligonucleotide libraries containing modified nucleotides are increasingly being used for selection. Principally, the choice of modifications aims to increase aptamer potency by enhancing nuclease-resistance, or increasing target affinity by providing more target recognition functionality or generating more stable aptamer structures.
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Knudsen SM, Robertson MP, Ellington AD. In vitro selection using modified or unnatural nucleotides. ACTA ACUST UNITED AC 2008; Chapter 9:Unit 9.6. [PMID: 18428900 DOI: 10.1002/0471142700.nc0906s07] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The use of modified nucleotides in an RNA or DNA pool to be used for in vitro selection offers many potential advantages, such as the increased stability of the selected nucleic acid against nuclease degradation. This unit provides useful information and protocols for in vitro selection using modified nucleotides. It includes a discussion of when to use modified nucleotides; protocols for preparing a modified RNA pool and verifying its suitability for in vitro selection; and protocols for selecting and amplifying a functionally enriched pool.
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Wochner A, Menger M, Rimmele M. Characterisation of aptamers for therapeutic studies. Expert Opin Drug Discov 2007; 2:1205-24. [DOI: 10.1517/17460441.2.9.1205] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Abstract
Oligonucleotides can in a variety of ways inhibit gene expression by interfering with translation. Oligonucleotides that are complementary to a target mRNA, antisense oligonucleotides, can prevent translation either by cleaving the target or by physically blocking the process. Additionally, oligonucleotides can correct the undesired splicing of pre-mRNA. RNA interference using double-stranded oligoribonucleotides also results in cleavage of the target mRNA. Catalytically competent ribozymes and DNAzymes can have the same effect. Even with no RNA as target, oligonucleotides can be selected as aptamers to bind to any protein to inhibit its activity. Moreover, oligonucleotides can act as decoys particularly for transcription factors to prevent binding to the promoter. A different mode of action is the activation of Toll-like receptors to induce an immune response. Several pathways for drug development are still in their infancy, for example microRNAs and antagomirs.
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Affiliation(s)
- Fritz Eckstein
- Max-Planck-Institute for Experimental Medicine, Góttingen, Germany.
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Famulok M, Hartig JS, Mayer G. Functional aptamers and aptazymes in biotechnology, diagnostics, and therapy. Chem Rev 2007; 107:3715-43. [PMID: 17715981 DOI: 10.1021/cr0306743] [Citation(s) in RCA: 666] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Michael Famulok
- LIMES Institute, Program Unit Chemical Biology and Medicinal Chemistry, c/o Kekulé-Institut für Organische Chemie und Biochemie, Gerhard Domagk-Strasse 1, 53121 Bonn, Germany.
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