1
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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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2
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Xiao X, Li H, Zhao L, Zhang Y, Liu Z. Oligonucleotide aptamers: Recent advances in their screening, molecular conformation and therapeutic applications. Biomed Pharmacother 2021; 143:112232. [PMID: 34649356 DOI: 10.1016/j.biopha.2021.112232] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/04/2021] [Accepted: 09/19/2021] [Indexed: 01/08/2023] Open
Abstract
Aptamers are single stranded oligonucleotides with specific recognition and binding ability to target molecules, which can be obtained by Systematic Evolution of Ligands by Exponential Enrichment (SELEX). Aptamers have the advantages of low molecular weight, low immunogenicity, easy modification and high stability. They play promising role in promoting food safety, monitoring the environment and basic research, especially in clinical diagnosis and therapeutic drugs. To date, great achievements regarding the selection, modifications and application of aptamers have been made. However, since it is still a challenge to obtain aptamers with high affinity in a more effective way, few aptamer-based products have already successfully entered into clinical use. This review aims to provide a thorough overview of the latest advances in this rapidly developing field, focusing on aptamer screening methods for different targets, the structure of the interaction between aptamers and target substances, and the challenges and potential of current therapeutic aptamers.
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Affiliation(s)
- Xueran Xiao
- College of Pharmaceutical Sciences, Key Laboratory of Pharmaceutical Quality Control of Hebei Province, Institute of Life Science and Green Development, Hebei University, Baoding 071002, China
| | - Hui Li
- Department of Urology, Peking University International Hospital, Beijing 102206, China
| | - Lijian Zhao
- College of Pharmaceutical Sciences, Key Laboratory of Pharmaceutical Quality Control of Hebei Province, Institute of Life Science and Green Development, Hebei University, Baoding 071002, China
| | - Yanfen Zhang
- Technology Transfer Center, Hebei University, Baoding 071002, China.
| | - Zhongcheng Liu
- College of Pharmaceutical Sciences, Key Laboratory of Pharmaceutical Quality Control of Hebei Province, Institute of Life Science and Green Development, Hebei University, Baoding 071002, China.
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3
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Guo X, Chen GH. Capillary electrophoresis-based methodology for screening of oligonucleotide aptamers. Biomed Chromatogr 2021; 35:e5109. [PMID: 33660332 DOI: 10.1002/bmc.5109] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 01/28/2023]
Abstract
As a new molecular recognition element, oligonucleotide aptamer not only has higher affinity and specificity to target molecules, but also has the advantages of wide recognition range, in vitro synthesis and chemical stability compared with conventional antibodies. Since a kind of screening method termed systematic evolution of ligands by exponential enrichment (SELEX) was reported, scientists have extensively researched the methodology of how to highly and efficiently screen out aptamers from a library consisting of a large number of random oligonucleotides. Certainly capillary electrophoresis-based screening methodologies, including nonequilibrium capillary electrophoresis of equilibrium mixtures, equilibrium capillary electrophoresis of equilibrium mixtures, non-SELEX, ideal-filter capillary electrophoresis, capillary transient isotachophoresis, etc., are revolutionary. Compared with conventional SELEX, these capillary electrophoresis-based methodologies show incomparable advantages such as the single-round screening of aptamers and increased successful screening rate. Methodology studies on the screening process of aptamers are comprehensively reviewed.
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Affiliation(s)
- Xin Guo
- College of Food and Bioengineering, Jiangsu University, Zhenjiang, China.,Periodicals Agency of Jiangsu University, Zhenjiang, China
| | - Guan-Hua Chen
- College of Food and Bioengineering, Jiangsu University, Zhenjiang, China
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4
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Liu LS, Wang F, Ge Y, Lo PK. Recent Developments in Aptasensors for Diagnostic Applications. ACS APPLIED MATERIALS & INTERFACES 2021; 13:9329-9358. [PMID: 33155468 DOI: 10.1021/acsami.0c14788] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Aptamers are exciting smart molecular probes for specific recognition of disease biomarkers. A number of strategies have been developed to convert target-aptamer binding into physically detectable signals. Since the aptamer sequence was first discovered, a large variety of aptamer-based biosensors have been developed, with considerable attention paid to their potential applications in clinical diagnostics. So far, a variety of techniques in combination with a wide range of functional nanomaterials have been used for the design of aptasensors to further improve the sensitivity and detection limit of target determination. In this paper, the advantages of aptamers over traditional antibodies as the molecular recognition components in biosensors for high-throughput screening target molecules are highlighted. Aptamer-target pairing configurations are predominantly single- or dual-site binding; the design of recognition modes of each aptamer-target pairing configuration is described. Furthermore, signal transduction strategies including optical, electrical, mechanical, and mass-sensitive modes are clearly explained together with examples. Finally, we summarize the recent progress in the development of aptamer-based biosensors for clinical diagnosis, including detection of cancer and disease biomarkers and in vivo molecular imaging. We then conclude with a discussion on the advanced development and challenges of aptasensors.
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Affiliation(s)
- Ling Sum Liu
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Fei Wang
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Yonghe Ge
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Pik Kwan Lo
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
- Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institute of City University of Hong Kong, Shenzhen 518057, China
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5
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Hoshino H, Kasahara Y, Kuwahara M, Obika S. DNA Polymerase Variants with High Processivity and Accuracy for Encoding and Decoding Locked Nucleic Acid Sequences. J Am Chem Soc 2020; 142:21530-21537. [PMID: 33306372 DOI: 10.1021/jacs.0c10902] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Xenobiotic nucleic acids (XNAs) are chemically modified nucleic acid analogues with potential applications in nucleic acid-based therapeutics including nucleic acid aptamers, ribozymes, small interfering RNAs, and antisense oligonucleotides. We have developed a promising XNA for therapeutic uses, 2',4'-bridged nucleic acid (2',4'-BNA), also known as locked nucleic acid (LNA). Unlike the rational design of small interfering and antisense oligonucleotides, the development of LNA aptamers and catalysts requires genetically engineered polymerases that enable the synthesis of LNA from DNA and the converse reverse transcription. However, no LNA decoders or encoders with sufficient performance have been developed. In this study, we developed variants of KOD DNA polymerase, a family B DNA polymerase derived from Thermococcus kodakarensis KOD1, which are effective LNA decoders and encoders, via structural analyses. KOD DGLNK (KOD: N210D/Y409G/A485L/D614N/E664K) enabled LNA synthesis from DNA (DNA → LNA), and KOD DLK (KOD: N210D/A485L/E664K) enabled LNA reverse transcription to DNA (LNA → DNA). Both variants exhibited greatly improved efficiency and accuracy. Notably, we synthesized LNAs longer than one kilobase using KOD DGLNK. We also showed that these variants can accept 2'-O-methyl (2'-OMe), a common modification for therapeutic uses. Here, we also show that LNA and 2'-OMe mix aptamer can be practically obtained via SELEX. The variants can be used as powerful tools for creating XNA aptamers and catalysts to completely eliminate the natural species, DNA and RNA.
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Affiliation(s)
- Hidekazu Hoshino
- National Institutes of Biomedical Innovation, Health and Nutrition, 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan.,Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yuuya Kasahara
- National Institutes of Biomedical Innovation, Health and Nutrition, 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan.,Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Masayasu Kuwahara
- Graduate School of Integrated Basic Sciences, Nihon University, 3-25-40 Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan
| | - Satoshi Obika
- National Institutes of Biomedical Innovation, Health and Nutrition, 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan.,Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
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6
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Bifunctional Aptamer Drug Carrier Enabling Selective and Efficient Incorporation of an Approved Anticancer Drug Irinotecan to Fibrin Gels. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10238755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We have previously developed a bifunctional aptamer (bApt) binding to both human thrombin and camptothecin derivative (CPT1), and showed that bApt acts as a drug carrier under the phenomenon named selective oligonucleotide entrapment in fibrin polymers (SOEF), which enables efficient enrichment of CPT1 into fibrin gels, resulting in significant inhibition of tumor cell growth. However, although the derivative CPT1 exhibits anticancer activity, it is not an approved drug. In this study, we evaluated the binding properties of bApt to irinotecan, a camptothecin analog commonly used for anticancer drug therapy, in addition to unmodified camptothecin (CPT). Furthermore, we have revealed that irinotecan binds to bApt like CPT1 and is selectively concentrated on fibrin gels formed around the tumor cells under the SOEF phenomenon to suppress cell proliferation.
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7
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Uemachi H, Kasahara Y, Tanaka K, Okuda T, Yoneda Y, Obika S. Discovery of cell-internalizing artificial nucleic acid aptamers for lung fibroblasts and targeted drug delivery. Bioorg Chem 2020; 105:104321. [PMID: 33074117 DOI: 10.1016/j.bioorg.2020.104321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 09/24/2020] [Indexed: 12/31/2022]
Abstract
Lung fibroblasts play major roles in the lung repair/fibrosis process through synthesis and remodeling of extracellular matrix. Those aberrant activations and elevated proliferations are associated with several fibrotic lung diseases, such as idiopathic pulmonary fibrosis (IPF). Targeting fibroblasts is a promising approach for preventing aberrant remodeling of lung architecture and protect irreversible pulmonary fibrosis. In this study, we developed an aptamer that can target lung fibroblasts and explored its potential as a delivery vehicle of cytotoxic agents intracellularly. The aptamer was discovered from artificial nucleic acid libraries through cell-based systematic evolution of ligands by exponential enrichment (cell-SELEX). This indole-modified aptamer can bind to LL97A cells, a fibroblast cell line derived from IPF patients, with high affinity (Kd = 70 nM). It also showed affinity to other lung fibroblasts, while cross-reactivity to epithelial cells was minimal. An aptamer-monomethyl auristatin F (MMAF) conjugate was generated by hybridizing with complementary DNA linked to MMAF. The resulting aptamer-MMAF conjugate inhibited proliferation of fibroblasts but appeared non-toxic to non-targeted epithelial cells. Our results show that artificial nucleic acid aptamer may potentially be used for fibroblast-specific therapy and diagnostic applications.
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Affiliation(s)
- Hiro Uemachi
- Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan; National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka 567-0085, Japan; DSP Cancer Institute, Sumitomo Dainippon Pharma Co., Ltd., Osaka 554-0022, Japan
| | - Yuuya Kasahara
- Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan; National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka 567-0085, Japan.
| | - Keisuke Tanaka
- Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan; National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka 567-0085, Japan
| | - Takumi Okuda
- Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan; National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka 567-0085, Japan
| | - Yoshihiro Yoneda
- National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka 567-0085, Japan
| | - Satoshi Obika
- Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan; National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Osaka 567-0085, Japan
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8
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Zhu C, Yang G, Ghulam M, Li L, Qu F. Evolution of multi-functional capillary electrophoresis for high-efficiency selection of aptamers. Biotechnol Adv 2019; 37:107432. [PMID: 31437572 DOI: 10.1016/j.biotechadv.2019.107432] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/24/2019] [Accepted: 08/16/2019] [Indexed: 02/07/2023]
Abstract
Aptamers have drawn considerable attention as newly emerging molecular recognition elements in clinical diagnostics, drug delivery, therapeutics, environmental monitoring, and food safety analyses. As the in vitro screening antibody analogs, aptamers are enabled to recognize various types of targets with high affinity and specificity like or even superior to antibodies. However, the restrictions and inefficiency of selection have been hampering their wider application. Among various modified systematic evolution of ligands by exponential enrichment (SELEX) methods, capillary electrophoresis (CE)-SELEX holds multiple functions and advantages with the powerful qualitative and quantitative analysis capabilities, less consumption of sample and analytical reagent, natural binding environment, higher screening efficiency, and availability in multiple modes. This review summarizes the key developments in the area of CE-SELEX by leading research groups, including our teams' ten years of research and experience to help researchers fully understand and utilize CE-SELEX. Aptamers' history, applications, as well as the SELEX developments, have been briefly described; the advantages of CE-SELEX are highlighted compared with the conventional SELEX methods. Further, we describe some essential CE-SELEX models and provide an overview of the CE-SELEX, including the targets and ssDNA library, every technical point in the selection process, and post-SELEX protocol. We expect this review will inspire more researchers to have insight into the screening problems from CE-SELEX viewpoint and will help to improve the selection efficiency and probability of success to meet the growing needs of aptamers' discovery in bioanalytical and medical fields.
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Affiliation(s)
- Chao Zhu
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing 100081, China
| | - Ge Yang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing 100081, China
| | - Murtaza Ghulam
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing 100081, China
| | - Linsen Li
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing 100081, China
| | - Feng Qu
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing 100081, China.
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9
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Antipova OM, Zavyalova EG, Golovin AV, Pavlova GV, Kopylov AM, Reshetnikov RV. Advances in the Application of Modified Nucleotides in SELEX Technology. BIOCHEMISTRY (MOSCOW) 2018; 83:1161-1172. [PMID: 30472954 DOI: 10.1134/s0006297918100024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Aptamers are widely used as molecular recognition elements for detecting and blocking functional biological molecules. Since the common "alphabet" of DNA and RNA consists of only four letters, the chemical diversity of aptamers is less than the diversity of protein recognition elements built of 20 amino acids. Chemical modification of nucleotides enlarges the potential of DNA/RNA aptamers. This review describes the latest achievements in a variety of approaches to aptamers selection with an extended genetic alphabet.
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Affiliation(s)
- O M Antipova
- Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991, Russia. .,Apto-Pharm Ltd., Moscow, 115564, Russia
| | - E G Zavyalova
- Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991, Russia.,Apto-Pharm Ltd., Moscow, 115564, Russia
| | - A V Golovin
- Apto-Pharm Ltd., Moscow, 115564, Russia.,Lomonosov Moscow State University, Faculty of Bioengineering and Bioinformatics, Moscow, 119234, Russia.,Sechenov First Moscow State Medical University, Institute of Molecular Medicine, Moscow, 119991, Russia
| | - G V Pavlova
- Apto-Pharm Ltd., Moscow, 115564, Russia.,Sechenov First Moscow State Medical University, Institute of Molecular Medicine, Moscow, 119991, Russia.,Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.,Burdenko National Scientific and Practical Center for Neurosurgery, Ministry of Healthcare of the Russian Federation, Moscow, 125047, Russia
| | - A M Kopylov
- Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991, Russia.,Apto-Pharm Ltd., Moscow, 115564, Russia
| | - R V Reshetnikov
- Apto-Pharm Ltd., Moscow, 115564, Russia.,Lomonosov Moscow State University, Faculty of Bioengineering and Bioinformatics, Moscow, 119234, Russia.,Sechenov First Moscow State Medical University, Institute of Molecular Medicine, Moscow, 119991, Russia.,Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
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10
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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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11
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Fujita H, Inoue Y, Kuwahara M. Selective incorporation of foreign functionality into fibrin gels through a chemically modified DNA aptamer. Bioorg Med Chem Lett 2017; 28:35-39. [PMID: 29162456 DOI: 10.1016/j.bmcl.2017.11.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/09/2017] [Accepted: 11/10/2017] [Indexed: 01/08/2023]
Abstract
We found for the first time that a thrombin-binding DNA aptamer (TBA) is selectively entrapped in fibrin gels during the gel growth reaction catalyzed by thrombin. Furthermore, using this phenomenon, we successfully demonstrated multiple incorporation of amphiphilic aliphatic groups into fibrin gels via chemically modified TBA.
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Affiliation(s)
- Hiroto Fujita
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Yusuke Inoue
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Masayasu Kuwahara
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
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12
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Specific Light-Up System for Protein and Metabolite Targets Triggered by Initiation Complex Formation. Sci Rep 2017; 7:15191. [PMID: 29123195 PMCID: PMC5680199 DOI: 10.1038/s41598-017-15697-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 11/01/2017] [Indexed: 12/11/2022] Open
Abstract
Gene regulation systems are mimicked by simple quantitative detection of non-nucleic acid molecular targets such as protein and metabolite. Here, we describe a one-tube, one-step real-time quantitative detection methodology for isothermal signal amplification of those targets. Using this system, real-time quantitative detection of thrombin and streptomycin, which were used as examples for protein and metabolite targets, was successfully demonstrated with detection limits of at most 50 pM and 75 nM, respectively. Notably, the dynamic range of target concentrations could be obtained for over four orders of magnitude. Thus, our method is expected to serve as a point-of-care or on-site test for medical diagnosis and food and environmental hygiene.
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13
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Morihiro K, Kasahara Y, Obika S. Biological applications of xeno nucleic acids. MOLECULAR BIOSYSTEMS 2017; 13:235-245. [PMID: 27827481 DOI: 10.1039/c6mb00538a] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Xeno nucleic acids (XNAs) are a group of chemically modified nucleic acid analogues that have been applied to various biological technologies such as antisense oligonucleotides, siRNAs and aptamers.
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Affiliation(s)
- Kunihiko Morihiro
- National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan and Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Yuuya Kasahara
- National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan and Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Satoshi Obika
- National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan and Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
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14
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Volk DE, Lokesh GLR. Development of Phosphorothioate DNA and DNA Thioaptamers. Biomedicines 2017; 5:E41. [PMID: 28703779 PMCID: PMC5618299 DOI: 10.3390/biomedicines5030041] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/03/2017] [Accepted: 07/11/2017] [Indexed: 02/07/2023] Open
Abstract
Nucleic acid aptamers are short RNA- or DNA-based affinity reagents typically selected from combinatorial libraries to bind to a specific target such as a protein, a small molecule, whole cells or even animals. Aptamers have utility in the development of diagnostic, imaging and therapeutic applications due to their size, physico-chemical nature and ease of synthesis and modification to suit the application. A variety of oligonucleotide modifications have been used to enhance the stability of aptamers from nuclease degradation in vivo. The non-bridging oxygen atoms of the phosphodiester backbones of RNA and DNA aptamers can be substituted with one or two sulfur atoms, resulting in thioaptamers with phosphorothioate or phosphorodithioate linkages, respectively. Such thioaptamers are known to have increased binding affinity towards their target, as well as enhanced resistance to nuclease degradation. In this review, we discuss the development of phosphorothioate chemistry and thioaptamers, with a brief review of selection methods.
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Affiliation(s)
- David E Volk
- McGovern Medical School, Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center, Houston, TX 77030, USA.
| | - Ganesh L R Lokesh
- McGovern Medical School, Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center, Houston, TX 77030, USA.
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15
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Abstract
Aptamers are nucleic acids referred to as chemical antibodies as they bind to their specific targets with high affinity and selectivity. They are selected via an iterative process known as ‘selective evolution of ligands by exponential enrichment’ (SELEX). Aptamers have been developed against numerous cancer targets and among them, many tumor cell-membrane protein biomarkers. The identification of aptamers targeting cell-surface proteins has mainly been performed by two different strategies: protein- and cell-based SELEX, when the targets used for selection were proteins and cells, respectively. This review aims to update the literature on aptamers targeting tumor cell surface protein biomarkers, highlighting potentials, pitfalls of protein- and cell-based selection processes and applications of such selected molecules. Aptamers as promising agents for diagnosis and therapeutic approaches in oncology are documented, as well as aptamers in clinical development.
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16
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Minagawa H, Onodera K, Fujita H, Sakamoto T, Akitomi J, Kaneko N, Shiratori I, Kuwahara M, Horii K, Waga I. Selection, Characterization and Application of Artificial DNA Aptamer Containing Appended Bases with Sub-nanomolar Affinity for a Salivary Biomarker. Sci Rep 2017; 7:42716. [PMID: 28256555 PMCID: PMC5335659 DOI: 10.1038/srep42716] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 01/12/2017] [Indexed: 12/21/2022] Open
Abstract
We have attained a chemically modified DNA aptamer against salivary α-amylase (sAA), which attracts researchers’ attention as a useful biomarker for assessing human psychobiological and social behavioural processes, although high affinity aptamers have not been isolated from a random natural DNA library to date. For the selection, we used the base-appended base (BAB) modification, that is, a modified-base DNA library containing (E)-5-(2-(N-(2-(N6-adeninyl)ethyl))carbamylvinyl)-uracil in place of thymine. After eight rounds of selection, a 75 mer aptamer, AMYm1, which binds to sAA with extremely high affinity (Kd < 1 nM), was isolated. Furthermore, we have successfully determined the 36-mer minimum fragment, AMYm1-3, which retains target binding activity comparable to the full-length AMYm1, by surface plasmon resonance assays. Nuclear magnetic resonance spectral analysis indicated that the minimum fragment forms a specific stable conformation, whereas the predicted secondary structures were suggested to be disordered forms. Thus, DNA libraries with BAB-modifications can achieve more diverse conformations for fitness to various targets compared with natural DNA libraries, which is an important advantage for aptamer development. Furthermore, using AMYm1, a capillary gel electrophoresis assay and lateral flow assay with human saliva were conducted, and its feasibility was demonstrated.
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Affiliation(s)
- Hirotaka Minagawa
- Innovation Laboratory, NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-Ku, Tokyo 136-8627, Japan
| | - Kentaro Onodera
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Hiroto Fujita
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Taiichi Sakamoto
- Department of Life and Environmental Sciences, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino 275-0016, Japan
| | - Joe Akitomi
- Innovation Laboratory, NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-Ku, Tokyo 136-8627, Japan
| | - Naoto Kaneko
- Innovation Laboratory, NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-Ku, Tokyo 136-8627, Japan
| | - Ikuo Shiratori
- Innovation Laboratory, NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-Ku, Tokyo 136-8627, Japan
| | - Masayasu Kuwahara
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Katsunori Horii
- Innovation Laboratory, NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-Ku, Tokyo 136-8627, Japan
| | - Iwao Waga
- Innovation Laboratory, NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-Ku, Tokyo 136-8627, Japan
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17
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An Update on Aptamer-Based Multiplex System Approaches for the Detection of Common Foodborne Pathogens. FOOD ANAL METHOD 2017. [DOI: 10.1007/s12161-017-0814-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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18
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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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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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Meek KN, Rangel AE, Heemstra JM. Enhancing aptamer function and stability via in vitro selection using modified nucleic acids. Methods 2016; 106:29-36. [PMID: 27012179 DOI: 10.1016/j.ymeth.2016.03.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/15/2016] [Accepted: 03/16/2016] [Indexed: 11/29/2022] Open
Abstract
Nucleic acid aptamers have emerged as a promising alternative to antibodies for use as recognition elements in therapeutics, bioimaging, and analytical applications. A key benefit that aptamers possess relative to antibodies is their ability to be chemically synthesized. This advantage, coupled with the broad range of modified nucleotide building blocks that can be constructed using chemical synthesis, has enabled the discovery and development of modified aptamers having extraordinary affinity, specificity, and biostability. Early efforts to generate modified aptamers focused on selection of a native DNA or RNA aptamer, followed by post-selection trial-and-error testing of modifications. However, recent advances in polymerase engineering and templated nucleic acid synthesis have enabled the direct selection of aptamers having modified backbones and nucleobases. This review will discuss these technological advances and highlight the improvements in aptamer function that have been realized through in vitro selection of non-natural nucleic acids.
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Affiliation(s)
- Kirsten N Meek
- Department of Chemistry and the Center for Cell and Genome Science, University of Utah, 315 S 1400 E, Salt Lake City, UT 84112, United States
| | - Alexandra E Rangel
- Department of Chemistry and the Center for Cell and Genome Science, University of Utah, 315 S 1400 E, Salt Lake City, UT 84112, United States
| | - Jennifer M Heemstra
- Department of Chemistry and the Center for Cell and Genome Science, University of Utah, 315 S 1400 E, Salt Lake City, UT 84112, United States.
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21
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Morihiro K, Hasegawa O, Mori S, Tsunoda S, Obika S. C5-azobenzene-functionalized locked nucleic acid uridine: isomerization properties, hybridization ability, and enzymatic stability. Org Biomol Chem 2016; 13:5209-14. [PMID: 25853508 DOI: 10.1039/c5ob00477b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Oligonucleotides (ONs) modified with a locked nucleic acid (LNA) are widely used in the fields of therapeutics, diagnosis, and nanotechnology. There have been significant efforts towards developing LNA analogues bearing modified bridges to improve their hybridization ability, nuclease resistance, and pharmacokinetic profiles. Moreover, nucleobase modifications of LNA are useful strategies for the functionalization of ONs. Modifications of the C5-position of pyrimidine nucleobases are particularly interesting because they enable predictable positioning of functional groups in the major groove of the duplex. Here we report the synthesis of C5-azobenzene-functionalized LNA uridine (LNA-U(Az)) and properties of LNA-U(Az)-modified ONs, including isomerization properties, hybridization ability, and enzyme stability. LNA-U(Az) in ON is photo-isomerized effectively and reversibly by irradiation at 365 nm (trans to cis) and 450 nm (cis to trans). LNA-U(Az)-modified ONs show RNA-selective hybridization ability despite the large hydrophobic azobenzene moiety extending into the major groove of the duplex. The enzymatic stability of LNA-U(Az)-modified ONs is higher than that of natural and LNA-modified ONs with or without photo-irradiation. Our results indicate that LNA-U(Az) holds promise for RNA targeting and photo-switchable technologies.
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Affiliation(s)
- K Morihiro
- National Institute of Biomedical Innovation (NIBIO), 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan.
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22
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Elle IC, Karlsen KK, Terp MG, Larsen N, Nielsen R, Derbyshire N, Mandrup S, Ditzel HJ, Wengel J. Selection of LNA-containing DNA aptamers against recombinant human CD73. MOLECULAR BIOSYSTEMS 2016; 11:1260-70. [PMID: 25720604 DOI: 10.1039/c5mb00045a] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
LNA-containing DNA aptamers against CD73 (human ecto-5'-nucleotidase), a protein frequently overexpressed in solid tumours, were isolated by SELEX. A pre-defined stem-loop library, containing LNA in the forward primer region, was enriched with CD73 binding sequences through six rounds of SELEX with recombinant his-tagged CD73 immobilised on anti-his plates. Enriched pools isolated from rounds one, three and six were subjected to next-generation sequencing and analysed for enrichment using custom bioinformatics software. The software identified aptamer sequences via the primers and then performed several steps including sequence unification, clustering and alignment to identify enriched sequences. Three enriched sequences were synthesised for further analysis, two of which showed sequence similarities. These sequences exhibited binding to the recombinant CD73 with KD values of 10 nM and 3.5 nM when tested by surface plasmon resonance. Truncated variants of these aptamers and variants where the LNA nucleotides were substituted for the DNA equivalent also exhibited affinity for the recombinant CD73 in the low nanomolar range. In enzyme inhibition assays with recombinant CD73 the aptamer sequences were able to decrease the activity of the protein. However, the aptamers exhibited no binding to cellular CD73 by flow cytometry analysis likely since the epitope recognised by the aptamer was not available for binding on the cellular protein.
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Affiliation(s)
- Ida C Elle
- Nucleic Acid Center, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
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23
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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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24
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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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25
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Hagiwara K, Kasahara Y, Fujita H, Kuwahara M. Non-Equilibrium Capillary Electrophoresis of Equilibrium Mixtures-Based Affinity Separation and Selective Enrichment of a Long-Length DNA Aptamer. Aust J Chem 2016. [DOI: 10.1071/ch16272] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Non-equilibrium capillary electrophoresis of equilibrium mixtures (NECEEM) is a kinetic capillary electrophoresis method used for the affinity analysis of DNA binding to proteins or ligands as well as a rapid selection of DNA aptamers. However, long DNA strands (100-mer or more) are generally difficult to analyse by this method owing to their poor peak separation. Herein, we report optimized conditions (use of a neutral phosphate buffer with an ionic strength of 0.074 as a binding buffer and use of an 80-cm fused silica capillary with a 75-μm internal diameter) for the peak separation of a 100-mer thrombin-binding DNA aptamer-target complex and its consequent enrichment using the NECEEM-based capillary electrophoresis–systematic evolution of ligands by exponential enrichment (CE-SELEX) method.
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26
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27
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Alves Ferreira-Bravo I, Cozens C, Holliger P, DeStefano JJ. Selection of 2'-deoxy-2'-fluoroarabinonucleotide (FANA) aptamers that bind HIV-1 reverse transcriptase with picomolar affinity. Nucleic Acids Res 2015; 43:9587-99. [PMID: 26476448 PMCID: PMC4751925 DOI: 10.1093/nar/gkv1057] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 10/02/2015] [Indexed: 11/17/2022] Open
Abstract
Using a Systematic Evolution of Ligands by Exponential Enrichment (SELEX) protocol capable of selecting xeno-nucleic acid (XNA) aptamers, a 2′-deoxy-2′-fluoroarabinonucleotide (FANA) aptamer (referred to as FA1) to HIV-1 reverse transcriptase (HIV-1 RT) was selected. FA1 bound HIV-1 RT with KD,app values in the low pM range under different ionic conditions. Comparisons to published HIV-1 RT RNA and DNA aptamers indicated that FA1 bound at least as well as these aptamers. FA1 contained a 20 nucleotide 5′ DNA sequence followed by a 57 nucleotide region of FANA nucleotides. Removal of the fourteen 5′ DNA nucleotides did not affect binding. FA1's predicted structure was composed of four stems and four loops. All stem nucleotides could be modified to G-C base pairs (14 total changes) with a small effect on binding. Eliminating or altering most loop sequences reduced or abolished tight binding. Overall, results suggested that the structure and the sequence of FA1 were important for binding. FA1 showed strong inhibition of HIV-1 RT in extension assays while no specific binding to avian myeloblastosis or Moloney murine leukemia RTs was detected. A complete DNA version of FA1 showed low binding to HIV-1 RT, emphasizing the unique properties of FANA in HIV-1 RT binding.
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Affiliation(s)
- Irani Alves Ferreira-Bravo
- Cell Biology and Molecular Genetics, Bioscience Research Building, University of Maryland, College Park, MD 20742, USA Maryland Pathogen Research Institute, College Park, MD 20742, USA
| | - Christopher Cozens
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Philipp Holliger
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Jeffrey J DeStefano
- Cell Biology and Molecular Genetics, Bioscience Research Building, University of Maryland, College Park, MD 20742, USA Maryland Pathogen Research Institute, College Park, MD 20742, USA
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28
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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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29
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Kokil GR, Veedu RN, Ramm GA, Prins JB, Parekh HS. Type 2 diabetes mellitus: limitations of conventional therapies and intervention with nucleic acid-based therapeutics. Chem Rev 2015; 115:4719-43. [PMID: 25918949 DOI: 10.1021/cr5002832] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Ganesh R Kokil
- †School of Pharmacy, Pharmacy Australia Centre of Excellence, The University of Queensland, Brisbane, QLD 4102, Australia
| | - Rakesh N Veedu
- §Center for Comparative Genomics, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia.,∥Western Australian Neuroscience Research Institute, Perth, WA 6150, Australia.,‡School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane QLD 4072 Australia
| | - Grant A Ramm
- ⊥The Hepatic Fibrosis Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD 4006, Australia.,#Faculty of Medicine and Biomedical Sciences, The University of Queensland, Brisbane, QLD 4006, Australia
| | - Johannes B Prins
- ∇Mater Research Institute, The University of Queensland, Brisbane, QLD 4101, Australia
| | - Harendra S Parekh
- †School of Pharmacy, Pharmacy Australia Centre of Excellence, The University of Queensland, Brisbane, QLD 4102, Australia
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30
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Yufa R, Krylova SM, Bruce C, Bagg EA, Schofield CJ, Krylov SN. Emulsion PCR significantly improves nonequilibrium capillary electrophoresis of equilibrium mixtures-based aptamer selection: allowing for efficient and rapid selection of aptamer to unmodified ABH2 protein. Anal Chem 2014; 87:1411-9. [PMID: 25495441 DOI: 10.1021/ac5044187] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Nonequilibrium capillary electrophoresis of equilibrium mixtures (NECEEM), a homogeneous approach to select DNA aptamers, is among the most efficient partitioning techniques. In contrast with surface-based systematic evolution of ligands by exponential enrichment (SELEX) approaches, the ability of NECEEM to select aptamers to unmodified proteins in solution is preferable for identifying aptamers for eventual in vivo use. The high stringency and low sample volumes of NECEEM, although generally beneficial, can result in binding of very few aptamers, requiring highly efficient amplification to propagate them. When amplified with standard PCR, detectable library enrichment can fail due to the fast conversion of the aptamers into byproducts and preferential amplification of nonbinders. As an alternative, we proposed the use of emulsion PCR (ePCR), which is known to reduce byproduct formation, as a PCR mode for coupling with NECEEM partitioning. For the first time, we tested the advantages of ePCR in NECEEM-based aptamer selection to a medically relevant DNA repair enzyme, ABH2. We report that the combination of ePCR with NECEEM allowed for the selection of aptamers in the first three rounds of SELEX, while SELEX with conventional PCR failed in a number of attempts. Selected aptamers to an unmodified ABH2 protein have potential use in diagnostics and as leads for anticancer cotherapies, used as enhancements of alkylating agents in chemotherapy.
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Affiliation(s)
- Roman Yufa
- Department of Chemistry and Centre for Research on Biomolecular Interactions, York University , Toronto, Ontario M3J 1P3, Canada
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31
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Galievsky VA, Stasheuski AS, Krylov SN. Capillary Electrophoresis for Quantitative Studies of Biomolecular Interactions. Anal Chem 2014; 87:157-71. [DOI: 10.1021/ac504219r] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Victor A. Galievsky
- Department
of Chemistry and
Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | - Alexander S. Stasheuski
- Department
of Chemistry and
Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | - Sergey N. Krylov
- Department
of Chemistry and
Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
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32
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Fujita H, Nakajima K, Kasahara Y, Ozaki H, Kuwahara M. Polymerase-mediated high-density incorporation of amphiphilic functionalities into DNA: enhancement of nuclease resistance and stability in human serum. Bioorg Med Chem Lett 2014; 25:333-6. [PMID: 25475204 DOI: 10.1016/j.bmcl.2014.11.037] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 11/11/2014] [Accepted: 11/13/2014] [Indexed: 12/20/2022]
Abstract
Modified oligodeoxyribonucleotides (mdODNs) bearing multiple copies of an amphiphilic functional group were enzymatically synthesized by simultaneous incorporation of base-modified 5'-triphosphate analogs of 2'-deoxyguanosine (dG(am)TP), 2'-deoxyuridine (dU(am)TP), 2'-deoxyadenosine (dA(am)TP), and 2'-deoxycytosine (dC(am)TP). The amphiphilic functionality, that is, (E)-38,53-dioxo-2,5,8,11,14,17,20,23,26,29,32,35-dodecaoxa-39,52-diazapentapentacont-54-en-55-yl group, consists of the water soluble dodeca(ethylene glycol) chain and the hydrophobic dodecyl chain. An enzymatically synthesized ODN, composed of a 20-mer 5'-terminal segment containing 2'-O,4'-C-methylene-bridged/linked bicyclic ribonucleotide (B/L nucleotide) and a 12-mer 3'-terminal segment containing the nucleobase-modified analogs, exhibits very high resistance against phosphodiesterase I and is stable in human serum for a longer period when compared with ODN, where the 12-mer 3'-terminal segment contains unmodified nucleotides.
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Affiliation(s)
- Hiroto Fujita
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Kohsuke Nakajima
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Yuuya Kasahara
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan; National Institute of Biomedical Innovation (NIBIO), 7-6-8 Asagi, Saito, Ibaraki, Osaka 567-0085, Japan
| | - Hiroaki Ozaki
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Masayasu Kuwahara
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
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33
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Hagiwara K, Fujita H, Kasahara Y, Irisawa Y, Obika S, Kuwahara M. In vitro selection of DNA-based aptamers that exhibit RNA-like conformations using a chimeric oligonucleotide library that contains two different xeno-nucleic acids. MOLECULAR BIOSYSTEMS 2014; 11:71-6. [PMID: 25325213 DOI: 10.1039/c4mb00436a] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We successfully generated chimeric DNA aptamers that contained six nucleoside analogs of 2'-O,4'-C-methylene bridged/locked nucleic acid (2',4'-BNA/LNA) in the primer region and multiple guanosine analogs of 2'-deoxy-2'-fluoro-ribonucleic acid (FNA) in the non-primer region using capillary electrophoresis-systematic evolution of ligands by exponential enrichment (CE-SELEX). Active species enrichment became saturated only after five selection rounds, and we obtained DNA-based xeno-nucleic acid (XNA) aptamers that had high binding affinities for the target human thrombin, with dissociation constant (Kd) values of ≥10 nanomolar. Based on sequence and circular dichroism (CD) analyses, these XNA aptamers exhibited RNA-like conformations, which could cause DNA-based strands to adopt structurally diverse conformations.
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Affiliation(s)
- Kenta Hagiwara
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
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Pinheiro VB, Holliger P. Towards XNA nanotechnology: new materials from synthetic genetic polymers. Trends Biotechnol 2014; 32:321-8. [PMID: 24745974 PMCID: PMC4039137 DOI: 10.1016/j.tibtech.2014.03.010] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 12/21/2022]
Abstract
Nucleic acids display remarkable properties beyond information storage and propagation. The well-understood base pairing rules have enabled nucleic acids to be assembled into nanostructures of ever increasing complexity. Although nanostructures can be constructed using other building blocks, including peptides and lipids, it is the capacity to evolve that sets nucleic acids apart from all other nanoscale building materials. Nonetheless, the poor chemical and biological stability of DNA and RNA constrain their applications. Recent advances in nucleic acid chemistry and polymerase engineering enable the synthesis, replication, and evolution of a range of synthetic genetic polymers (XNAs) with improved chemical and biological stability. We discuss the impact of this technology on the generation of XNA ligands, enzymes, and nanostructures with tailor-made chemistry.
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Affiliation(s)
- Vitor B Pinheiro
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Philipp Holliger
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
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Improvement of a streptavidin-binding aptamer by LNA- and α-l-LNA-substitutions. Bioorg Med Chem Lett 2014; 24:2273-7. [PMID: 24745966 DOI: 10.1016/j.bmcl.2014.03.082] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 03/24/2014] [Accepted: 03/25/2014] [Indexed: 12/20/2022]
Abstract
Forty modified versions of a streptavidin-binding aptamer each containing single or multiple LNA or α-l-LNA-substitutions were synthesized and their dissociation constants determined by surface plasmon resonance experiments. Both full-length and truncated versions of the aptamer were studied and compared with the unmodified DNA aptamers. A ∼two-fold improvement in binding affinity was achieved by incorporation of LNA nucleotides in the 3'-part of the stems of the streptavidin-binding aptamer whereas LNA- and α-l-LNA-substitutions in the terminal stem increased the serum stability.
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36
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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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37
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Kong HY, Byun J. Nucleic Acid aptamers: new methods for selection, stabilization, and application in biomedical science. Biomol Ther (Seoul) 2014; 21:423-34. [PMID: 24404332 PMCID: PMC3879913 DOI: 10.4062/biomolther.2013.085] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 11/05/2013] [Accepted: 11/05/2013] [Indexed: 12/19/2022] Open
Abstract
The adoption of oligonucleotide aptamer is well on the rise, serving an ever increasing demand for versatility in biomedical field. Through the SELEX (Systematic Evolution of Ligands by EXponential enrichment), aptamer that can bind to specific target with high affinity and specificity can be obtained. Aptamers are single-stranded nucleic acid molecules that can fold into complex threedimensional structures, forming binding pockets and clefts for the specific recognition and tight binding of any given molecular target. Recently, aptamers have attracted much attention because they not only have all of the advantages of antibodies, but also have unique merits such as thermal stability, ease of synthesis, reversibility, and little immunogenicity. The advent of novel technologies is revolutionizing aptamer applications. Aptamers can be easily modified by various chemical reactions to introduce functional groups and/or nucleotide extensions. They can also be conjugated to therapeutic molecules such as drugs, drug containing carriers, toxins, or photosensitizers. Here, we discuss new SELEX strategies and stabilization methods as well as applications in drug delivery and molecular imaging.
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Affiliation(s)
- Hoon Young Kong
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, Yongin 448-701, Republic of Korea
| | - Jonghoe Byun
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, Yongin 448-701, Republic of Korea
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38
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Kuwahara M, Obika S. In vitro selection of BNA (LNA) aptamers. ARTIFICIAL DNA, PNA & XNA 2014; 4:39-48. [PMID: 24044051 DOI: 10.4161/adna.25786] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 07/17/2013] [Indexed: 01/03/2023]
Abstract
Recently, we achieved the first in vitro selection of 2'-O,4'-C-methylene bridged/locked nucleic acid (2',4'-BNA/LNA) aptamers. High-affinity thrombin-binding aptamers (TBAs) were obtained from DNA-based libraries containing 2'-O,4'-C-methylene-bridged/linked bicyclic ribonucleotides (B/L nucleotides) in the 5'-primer region, using the method of capillary electrophoresis systematic evolution of ligands by exponential enrichment (CE-SELEX). Furthermore, a similar selection protocol could provide TBAs that contain B/L nucleotides in both primer and random regions. We review technical challenges involved in the generation of various BNA libraries using analogs of B/L nucleoside-5'-triphosphate and polymerase variants and also discuss applications of these libraries to the selection of BNA (LNA) aptamers, as well as future prospects for their therapeutic and diagnostic uses.
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Affiliation(s)
- Masayasu Kuwahara
- Graduate School of Science and Technology; Gunma University; Gunma, Japan
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Shigdar S, Macdonald J, O'Connor M, Wang T, Xiang D, Al.Shamaileh H, Qiao L, Wei M, Zhou SF, Zhu Y, Kong L, Bhattacharya S, Li C, Duan W. Aptamers as theranostic agents: modifications, serum stability and functionalisation. SENSORS 2013; 13:13624-37. [PMID: 24152925 PMCID: PMC3859083 DOI: 10.3390/s131013624] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/24/2013] [Accepted: 09/27/2013] [Indexed: 02/07/2023]
Abstract
Aptamers, and the selection process known as Systematic Evolution of Ligands by Exponential Enrichment (SELEX) used to generate them, were first described more than twenty years ago. Since then, there have been numerous modifications to the selection procedures. This review discusses the use of modified bases as a means of enhancing serum stability and producing effective therapeutic tools, as well as functionalising these nucleic acids to be used as potential diagnostic agents.
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Affiliation(s)
- Sarah Shigdar
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
- Authors to whom correspondence should be addressed; E-Mails: (S.S.); (W.D.)
| | - Joanna Macdonald
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Michael O'Connor
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Tao Wang
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Dongxi Xiang
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Hadi Al.Shamaileh
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Liang Qiao
- Storr Liver Unit, at the Westmead Millennium Institute, The University of Sydney at the Westmead Hospital, Westmead NSW 2145, Australia; E-Mail:
| | - Ming Wei
- School of Medical Science and Griffith Health Institute, Griffith University, Gold Coast Campus, Southport 4222, Australia; E-Mail:
| | - Shu-Feng Zhou
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL 33612, USA; E-Mail:
| | - Yimin Zhu
- Suzhou Key Laboratory of Nanobiomedicine, Division of Nanobiomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China; E-Mail:
| | - Lingxue Kong
- Institute for Frontier Materials, Deakin University, Waurn Ponds, Victoria 3217, Australia; E-Mail:
| | - Santanu Bhattacharya
- Department of Organic Chemistry, Indian Institute of Science, Bangalore 560 012, India; E-Mail:
| | - ChunGuang Li
- Centre for Complimentary Medicine Research, National Institute of Complementary Medicine, University of Western Sydney, Campbelltown Campus, Penrith, NSW 2751, Australia; E-Mail:
| | - Wei Duan
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
- Authors to whom correspondence should be addressed; E-Mails: (S.S.); (W.D.)
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40
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Kasahara Y, Irisawa Y, Fujita H, Yahara A, Ozaki H, Obika S, Kuwahara M. Capillary electrophoresis-systematic evolution of ligands by exponential enrichment selection of base- and sugar-modified DNA aptamers: target binding dominated by 2'-O,4'-C-methylene-bridged/locked nucleic acid primer. Anal Chem 2013; 85:4961-7. [PMID: 23662585 DOI: 10.1021/ac400058z] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Chemically modified DNA aptamers specific to human α-thrombin were obtained from oligodeoxyribonucleotide (ODN) libraries by using a capillary electrophoresis-systematic evolution of ligands by exponential enrichment (CE-SELEX) method. These libraries contained 2'-O,4'-C-methylene-bridged/linked bicyclic ribonucleotides (B/L nucleotides) in the primer region and/or C5-modified thymidine bearing N(6)-ethyladenine (t) in the nonprimer region. Modified DNA aptamers showed high binding affinities to the target, with dissociation constants (Kd) values in the range of subnanomolar to several ten nanomolar levels. The introduction of base modification significantly suppressed the frequency of G-quadruplex motifs, which are often seen in thrombin-binding DNA aptamers. The resulting alternatives contained the 10-mer consensus sequence t5Gt2G2, which is frequently found in modified DNA aptamers with subnanomolar protein binding affinities. Furthermore, some base- and sugar-modified DNA aptamers with the 12-mer consensus sequence t2G2tC(A/G)A2G2t displayed binding activities that were dependent on the presence of B/L nucleotides in the primer region. Such aptamers were interestingly not recovered from a natural DNA library or from DNA libraries modified with either B/L nucleotides or t's. This emerging characteristic binding property will enable the creation of a direct selection methodology for DNA-based molecular switches that are triggered by chemical conversion of B/L nucleotides introduced to constant sequence regions in ODN libraries.
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Affiliation(s)
- Yuuya Kasahara
- Graduate School of Science and Technology, Gunma University, Kiryu, Gunma, Japan
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41
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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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