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Dzuvor CKO, Tettey EL, Danquah MK. Aptamers as promising nanotheranostic tools in the COVID-19 pandemic era. WILEY INTERDISCIPLINARY REVIEWS. NANOMEDICINE AND NANOBIOTECHNOLOGY 2022; 14:e1785. [PMID: 35238490 PMCID: PMC9111085 DOI: 10.1002/wnan.1785] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/02/2022] [Accepted: 02/07/2022] [Indexed: 12/13/2022]
Abstract
The emergence of SARS-COV-2, the causative agent of new coronavirus disease (COVID-19) has become a pandemic threat. Early and precise detection of the virus is vital for effective diagnosis and treatment. Various testing kits and assays, including nucleic acid detection methods, antigen tests, serological tests, and enzyme-linked immunosorbent assay (ELISA), have been implemented or are being explored to detect the virus and/or characterize cellular and antibody responses to the infection. However, these approaches have inherent drawbacks such as nonspecificity, high cost, are characterized by long turnaround times for test results, and can be labor-intensive. Also, the circulating SARS-COV-2 variant of concerns, reduced antibody sensitivity and/or neutralization, and possible antibody-dependent enhancement (ADE) have warranted the search for alternative potent therapeutics. Aptamers, which are single-stranded oligonucleotides, generated artificially by SELEX (Evolution of Ligands by Exponential Enrichment) may offer the capacity to generate high-affinity neutralizers and/or bioprobes for monitoring relevant SARS-COV-2 and COVID-19 biomarkers. This article reviews and discusses the prospects of implementing aptamers for rapid point-of-care detection and treatment of SARS-COV-2. We highlight other SARS-COV-2 targets (N protein, spike protein stem-helix), SELEX augmented with competition assays and in silico technologies for rapid discovery and isolation of theranostic aptamers against COVID-19 and future pandemics. It further provides an overview on site-specific bioconjugation approaches, customizable molecular scaffolding strategies, and nanotechnology platforms to engineer these aptamers into ultrapotent blockers, multivalent therapeutics, and vaccines to boost both humoral and cellular immunity against the virus. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Diagnostic Tools > Biosensing Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Respiratory Disease.
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Affiliation(s)
- Christian K. O. Dzuvor
- Bioengineering Laboratory, Department of Chemical and Biological EngineeringMonash UniversityClaytonVictoriaAustralia
| | | | - Michael K. Danquah
- Department of Chemical EngineeringUniversity of TennesseeChattanoogaTennesseeUSA
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2
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Nanoparticle-based strategies to target HIV-infected cells. Colloids Surf B Biointerfaces 2022; 213:112405. [PMID: 35255375 DOI: 10.1016/j.colsurfb.2022.112405] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/31/2022] [Accepted: 02/07/2022] [Indexed: 02/06/2023]
Abstract
Antiretroviral drugs employed for the treatment of human immunodeficiency virus (HIV) infections have remained largely ineffective due to their poor bioavailability, numerous adverse effects, modest uptake in infected cells, undesirable drug-drug interactions, the necessity for long-term drug therapy, and lack of access to tissues and reservoirs. Nanotechnology-based interventions could serve to overcome several of these disadvantages and thereby improve the therapeutic efficacy of antiretrovirals while reducing the morbidity and mortality due to the disease. However, attempts to use nanocarriers for the delivery of anti-retroviral drugs have started gaining momentum only in the past decade. This review explores in-depth the various nanocarriers that have been employed for the treatment of HIV infections highlighting their merits and possible demerits.
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Srivastava S, Abraham PR, Mukhopadhyay S. Aptamers: An Emerging Tool for Diagnosis and Therapeutics in Tuberculosis. Front Cell Infect Microbiol 2021; 11:656421. [PMID: 34277465 PMCID: PMC8280756 DOI: 10.3389/fcimb.2021.656421] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 06/09/2021] [Indexed: 11/13/2022] Open
Abstract
Tuberculosis (TB) has been plaguing human civilization for centuries, and currently around one-third of the global population is affected with TB. Development of novel intervention tools for early diagnosis and therapeutics against Mycobacterium tuberculosis (M.tb) is the main thrust area in today's scenario. In this direction global efforts were made to use aptamers, the chemical antibodies as tool for TB diagnostics and therapeutics. This review describes the various aptamers introduced for targeting M.tb and highlights the need for development of novel aptamers to selectively target virulent proteins of M.tb for vaccine and anti-TB drugs. The objective of this review is to highlight the diagnostic and therapeutic application of aptamers used for tuberculosis. The discovery of aptamers, SELEX technology, different types of SELEX development processes, DNA and RNA aptamers reported for diseases and pathogenic agents as well have also been described in detail. But the emphasis of this review is on the development of aptamers which can block the function of virulent mycobacterial components for developing newer TB vaccine candidates and/or drug targets. Aptamers designed to target M.tb cell wall proteins, virulent factors, secretory proteins, or combination could orchestrate advanced diagnosis and therapeutic measures for tuberculosis.
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Affiliation(s)
- Shruti Srivastava
- Laboratory of Molecular Cell Biology, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India
| | - Philip Raj Abraham
- Unit of OMICS, ICMR-Vector Control Research Centre (VCRC), Puducherry, India
| | - Sangita Mukhopadhyay
- Laboratory of Molecular Cell Biology, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India
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4
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Saran R, Huang Z, Liu J. Phosphorothioate nucleic acids for probing metal binding, biosensing and nanotechnology. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2020.213624] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Bognár Z, Gyurcsányi RE. Aptamers against Immunoglobulins: Design, Selection and Bioanalytical Applications. Int J Mol Sci 2020; 21:E5748. [PMID: 32796581 PMCID: PMC7461046 DOI: 10.3390/ijms21165748] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/26/2020] [Accepted: 08/06/2020] [Indexed: 12/11/2022] Open
Abstract
Nucleic acid aptamers show clear promise as diagnostic reagents, as highly specific strands were reported against a large variety of biomarkers. They have appealing benefits in terms of reproducible generation by chemical synthesis, controlled modification with labels and functionalities providing versatile means for detection and oriented immobilization, as along with high biochemical and temperature resistance. Aptamers against immunoglobulin targets-IgA, IgM, IgG and IgE-have a clear niche for diagnostic applications, therefore numerous aptamers have been selected and used in combination with a variety of detection techniques. The aim of this review is to overview and evaluate aptamers selected for the recognition of antibodies, in terms of their design, analytical properties and diagnostic applications. Aptamer candidates showed convincing performance among others to identify stress and upper respiratory tract infection through SIgA detection, for cancer cell recognition using membrane bound IgM, to detect and treat hemolytic transfusion reactions, autoimmune diseases with IgG and detection of IgE for allergy diseases. However, in general, their use still lags significantly behind what their claimed benefits and the plethora of application opportunities would forecast.
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Affiliation(s)
| | - Róbert E. Gyurcsányi
- BME “Lendület” Chemical Nanosensors Research Group, Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4, H-1111 Budapest, Hungary;
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Odeh F, Nsairat H, Alshaer W, Ismail MA, Esawi E, Qaqish B, Bawab AA, Ismail SI. Aptamers Chemistry: Chemical Modifications and Conjugation Strategies. Molecules 2019; 25:E3. [PMID: 31861277 PMCID: PMC6982925 DOI: 10.3390/molecules25010003] [Citation(s) in RCA: 193] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 12/14/2019] [Accepted: 12/17/2019] [Indexed: 12/21/2022] Open
Abstract
Soon after they were first described in 1990, aptamers were largely recognized as a new class of biological ligands that can rival antibodies in various analytical, diagnostic, and therapeutic applications. Aptamers are short single-stranded RNA or DNA oligonucleotides capable of folding into complex 3D structures, enabling them to bind to a large variety of targets ranging from small ions to an entire organism. Their high binding specificity and affinity make them comparable to antibodies, but they are superior regarding a longer shelf life, simple production and chemical modification, in addition to low toxicity and immunogenicity. In the past three decades, aptamers have been used in a plethora of therapeutics and drug delivery systems that involve innovative delivery mechanisms and carrying various types of drug cargos. However, the successful translation of aptamer research from bench to bedside has been challenged by several limitations that slow down the realization of promising aptamer applications as therapeutics at the clinical level. The main limitations include the susceptibility to degradation by nucleases, fast renal clearance, low thermal stability, and the limited functional group diversity. The solution to overcome such limitations lies in the chemistry of aptamers. The current review will focus on the recent arts of aptamer chemistry that have been evolved to refine the pharmacological properties of aptamers. Moreover, this review will analyze the advantages and disadvantages of such chemical modifications and how they impact the pharmacological properties of aptamers. Finally, this review will summarize the conjugation strategies of aptamers to nanocarriers for developing targeted drug delivery systems.
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Affiliation(s)
- Fadwa Odeh
- Faculty of Science, The University of Jordan, Amman 11942, Jordan; (F.O.); (H.N.); (A.A.B.)
- Hamdi Mango Center for Scientific Research, The University of Jordan, Amman 11942, Jordan
| | - Hamdi Nsairat
- Faculty of Science, The University of Jordan, Amman 11942, Jordan; (F.O.); (H.N.); (A.A.B.)
| | - Walhan Alshaer
- Cell Therapy Center, The University of Jordan, Amman 11942, Jordan
| | - Mohammad A. Ismail
- Faculty of Medicine, The University of Jordan, Amman 11942, Jordan; (M.A.I.); (E.E.); (B.Q.); (S.I.I.)
| | - Ezaldeen Esawi
- Faculty of Medicine, The University of Jordan, Amman 11942, Jordan; (M.A.I.); (E.E.); (B.Q.); (S.I.I.)
| | - Baraa Qaqish
- Faculty of Medicine, The University of Jordan, Amman 11942, Jordan; (M.A.I.); (E.E.); (B.Q.); (S.I.I.)
| | - Abeer Al Bawab
- Faculty of Science, The University of Jordan, Amman 11942, Jordan; (F.O.); (H.N.); (A.A.B.)
- Hamdi Mango Center for Scientific Research, The University of Jordan, Amman 11942, Jordan
| | - Said I. Ismail
- Faculty of Medicine, The University of Jordan, Amman 11942, Jordan; (M.A.I.); (E.E.); (B.Q.); (S.I.I.)
- Qatar Genome Project, Qatar Foundation, Doha 5825, Qatar
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Rose KM, Alves Ferreira-Bravo I, Li M, Craigie R, Ditzler MA, Holliger P, DeStefano JJ. Selection of 2'-Deoxy-2'-Fluoroarabino Nucleic Acid (FANA) Aptamers That Bind HIV-1 Integrase with Picomolar Affinity. ACS Chem Biol 2019; 14:2166-2175. [PMID: 31560515 PMCID: PMC7005942 DOI: 10.1021/acschembio.9b00237] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
![]()
Systematic Evolution
of Ligands by Exponential Enrichment (SELEX)
is the iterative process by which nucleic acids that can bind with
high affinity and specificity (termed aptamers) to specific protein
targets are selected. Using a SELEX protocol adapted for Xeno-Nucleic
Acid (XNA) as a suitable substrate for aptamer generation, 2′-fluoroarabinonucleic
acid (FANA) was used to select several related aptamers to HIV-1 integrase
(IN). IN bound FANA aptamers with equilibrium dissociation constants
(KD,app) of ∼50–100 pM in
a buffer with 200 mM NaCl and 6 mM MgCl2. Comparisons to
published HIV-1 IN RNA and DNA aptamers as well as IN genomic binding
partners indicated that FANA aptamers bound more than 2 orders of
magnitude more tightly to IN. Using a combination of RNA folding algorithms
and covariation analysis, all strong binding aptamers demonstrated
a common four-way junction structure, despite significant sequence
variation. IN aptamers were selected from the same starting library
as FA1, a FANA aptamer that binds with pM affinity to HIV-1 Reverse
Transcriptase (RT). It contains a 20-nucleotide 5′ DNA sequence
followed by 59 FANA nucleotides. IN-1.1 (one of the selected aptamers)
potently inhibited IN activity and intasome formation in vitro. Replacing
the FANA nucleotides of IN-1.1 with 2′-fluororibonucleic acid
(F-RNA), which has the same chemical formula but with a ribose rather
than arabinose sugar conformation, dramatically reduced binding, suggesting
that FANA adopts unique structural conformations that promote binding
to HIV-1 IN.
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Molefe PF, Masamba P, Oyinloye BE, Mbatha LS, Meyer M, Kappo AP. Molecular Application of Aptamers in the Diagnosis and Treatment of Cancer and Communicable Diseases. Pharmaceuticals (Basel) 2018; 11:ph11040093. [PMID: 30274155 PMCID: PMC6315466 DOI: 10.3390/ph11040093] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/20/2018] [Accepted: 09/24/2018] [Indexed: 12/18/2022] Open
Abstract
Cancer and infectious diseases such as Ebola, HIV, tuberculosis, Zika, hepatitis, measles and human schistosomiasis are serious global health hazards. The increasing annual morbidities and mortalities of these diseases have been blamed on drug resistance and the inefficacy of available diagnostic tools, particularly those which are immunologically-based. Antibody-based tools rely solely on antibody production for diagnosis and for this reason they are the major cause of diagnostic delays. Unfortunately, the control of these diseases depends on early detection and administration of effective treatment therefore any diagnostic delay is a huge challenge to curbing these diseases. Hence, there is a need for alternative diagnostic tools, discovery and development of novel therapeutic agents. Studies have demonstrated that aptamers could potentially offer one of the best solutions to these problems. Aptamers are short sequences of either DNA or RNA molecules, which are identified in vitro through a SELEX process. They are sensitive and bind specifically to target molecules. Their promising features suggest they may serve as better diagnostic agents and can be used as drug carriers for therapeutic purposes. In this article, we review the applications of aptamers in the theranostics of cancer and some infectious diseases.
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Affiliation(s)
- Philisiwe Fortunate Molefe
- Biotechnology and Structural Biochemistry (BSB) Group, Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa.
| | - Priscilla Masamba
- Biotechnology and Structural Biochemistry (BSB) Group, Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa.
| | - Babatunji Emmanuel Oyinloye
- Biotechnology and Structural Biochemistry (BSB) Group, Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa.
- Department of Biochemistry, College of Sciences, Afe Babalola University, PMB 5454, Ado-Ekiti 360001, Nigeria.
| | - Londiwe Simphiwe Mbatha
- Biotechnology and Structural Biochemistry (BSB) Group, Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa.
| | - Mervin Meyer
- DST/Mintek Nanotechnology Innovation Centre, Biolabels Node, Department of Biotechnology, University of the Western Cape, Bellville 7535, South Africa.
| | - Abidemi Paul Kappo
- Biotechnology and Structural Biochemistry (BSB) Group, Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa.
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9
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Pan Q, Luo F, Liu M, Zhang XL. Oligonucleotide aptamers: promising and powerful diagnostic and therapeutic tools for infectious diseases. J Infect 2018; 77:83-98. [PMID: 29746951 PMCID: PMC7112547 DOI: 10.1016/j.jinf.2018.04.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 01/02/2018] [Accepted: 04/08/2018] [Indexed: 12/21/2022]
Abstract
The entire human population is at risk of infectious diseases worldwide. Thus far, the diagnosis and treatment of human infectious diseases at the molecular and nanoscale levels have been extremely challenging tasks because of the lack of effective probes to identify and recognize biomarkers of pathogens. Oligonucleotide aptamers are a class of small nucleic acid ligands that are composed of single-stranded DNA (ssDNA) or RNA and act as affinity probes or molecular recognition elements for a variety of targets. These aptamers have an exciting potential for diagnose and/or treatment of specific diseases. In this review, we highlight areas where aptamers have been developed as diagnostic and therapeutic agents for both bacterial and viral infectious diseases as well as aptamer-based detection.
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Affiliation(s)
- Qin Pan
- State Key Laboratory of Virology and Department of Immunology School of Basic Medical Sciences, Medical Research Institute and Hubei Province Key Laboratory of Allergy Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, PR China
| | - Fengling Luo
- State Key Laboratory of Virology and Department of Immunology School of Basic Medical Sciences, Medical Research Institute and Hubei Province Key Laboratory of Allergy Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, PR China
| | - Min Liu
- State Key Laboratory of Virology and Department of Immunology School of Basic Medical Sciences, Medical Research Institute and Hubei Province Key Laboratory of Allergy Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, PR China
| | - Xiao-Lian Zhang
- State Key Laboratory of Virology and Department of Immunology School of Basic Medical Sciences, Medical Research Institute and Hubei Province Key Laboratory of Allergy Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, PR China.
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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: 42] [Impact Index Per Article: 6.0] [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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Houlihan G, Arangundy-Franklin S, Holliger P. Engineering and application of polymerases for synthetic genetics. Curr Opin Biotechnol 2017; 48:168-179. [PMID: 28601700 DOI: 10.1016/j.copbio.2017.04.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 11/26/2022]
Abstract
Organic chemistry has systematically probed the chemical determinants of function in nucleic acids by variation to the nucleobase, sugar ring and backbone moieties to build synthetic genetic polymers. Concomitantly, protein engineering has advanced to allow the discovery of polymerases capable of utilizing modified nucleotide analogs. A conjunction of these two lines of investigation in nucleotide chemistry and molecular biology has given rise to a new field of synthetic genetics dedicated to the exploration of the capacity of these novel, synthetic nucleic acids for the storage and propagation of genetic information, for evolution and for crosstalk, that is, information exchange with the natural genetic system. Here we summarize recent progress in synthetic genetics, specifically in the design of novel unnatural basepairs to expand the genetic alphabet as well as progress in engineering polymerases capable of templated synthesis, reverse transcription and evolution of synthetic genetic polymers.
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Affiliation(s)
- Gillian Houlihan
- 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.
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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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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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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: 90] [Impact Index Per Article: 10.0] [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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15
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Selection of a novel DNA thioaptamer against HER2 structure. Clin Transl Oncol 2015; 17:647-56. [PMID: 26022131 DOI: 10.1007/s12094-015-1292-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 04/20/2015] [Indexed: 12/26/2022]
Abstract
PURPOSE Human epithelial growth factor receptor 2 (HER2) is over-expressed in several malignancies and represents an important therapeutic target. Aptamers are oligonucleotides that may potentially serve as tumor-homing ligand with excellent affinity and specificity for targeted cancer therapy. However, aptamers need to have nuclease resistance in order to function in vivo. The aim of this study was to generate a novel HER2 thioaptamer with enhanced nuclease resistance. METHODS The HER2 thioaptamer is selected in an evolutionary process called systematic evolution of ligands by exponential enrichment. RESULTS The thioaptamer could bind to the extracellular domain of HER2 with a K d of 172 nM and had minimal cross reactivity to trypsin or IgG. Moreover, the thioaptamer was found capable of binding with the HER2-positive breast cancer cells SK-BR-3 and MDA-MB-453, but not the HER2-negative cells MDA-MB-231. Notably, the thioaptamer HY6 largely maintained its structural integrity facing the nucleases in serum, while regular DNA aptamers were mostly digested. Additionally, the thioaptamer retained the capability of binding with the HER2-positive cells in the presence of serum, whereas non-thionated HER2 aptamer lost the binding function. CONCLUSION The results indicated that the selected thioaptamer was more resistant to nuclease than regular DNA aptamers and might potentially function as a HER2-targeting ligand in complicated environment.
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High-affinity RNA Aptamers Against the HIV-1 Protease Inhibit Both In Vitro Protease Activity and Late Events of Viral Replication. MOLECULAR THERAPY. NUCLEIC ACIDS 2015; 4:e228. [PMID: 25689224 PMCID: PMC4345311 DOI: 10.1038/mtna.2015.1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 12/01/2014] [Indexed: 12/19/2022]
Abstract
HIV-1 aspartyl protease (PR) plays a key role in virion morphogenesis, underscoring the effectiveness of protease inhibitors (PI). Despite their utility, side effects and drug-resistance remains a problem. We report the development of RNA aptamers as inhibitors of HIV-1 PR for potential use in anti-HIV gene therapy. Employing Systematic Evolution of Ligands by Exponential Enrichment (SELEX), we isolated four unique families of anti-HIV-1 PR RNA aptamers displaying moderate binding affinities (Kd = 92–140 nmol/l) and anti-PR inhibitory activity (Kis = 138–647 nmol/l). Second-generation RNA aptamers selected from partially randomized pools based on two of the aptamer sequences displayed striking enhancements in binding (Kds = 2–22 nmol/l) and inhibition (Kis = 31–49 nmol/l). The aptamers were specific in that they did not bind either the related HIV-2 protease, or the cellular aspartyl protease, Cathepsin D. Site-directed mutagenesis of a second-generation aptamer to probe the predicted secondary structure indicated that the stem-loops SL2 and SL3 and the stem P1 were essential for binding and that only the 3'-most 17 nucleotides were dispensable. Anti-PR aptamers inhibited HIV replication in vitro and the degree of inhibition was higher for second-generation aptamers with greater affinity and the inhibition was abrogated for a nonbinding aptamer variant.
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Aptamers in diagnostics and treatment of viral infections. Viruses 2015; 7:751-80. [PMID: 25690797 PMCID: PMC4353915 DOI: 10.3390/v7020751] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 01/13/2015] [Accepted: 02/12/2015] [Indexed: 02/07/2023] Open
Abstract
Aptamers are in vitro selected DNA or RNA molecules that are capable of binding a wide range of nucleic and non-nucleic acid molecules with high affinity and specificity. They have been conducted through the process known as SELEX (Systematic Evolution of Ligands by Exponential Enrichment). It serves to reach specificity and considerable affinity to target molecules, including those of viral origin, both proteins and nucleic acids. Properties of aptamers allow detecting virus infected cells or viruses themselves and make them competitive to monoclonal antibodies. Specific aptamers can be used to interfere in each stage of the viral replication cycle and also inhibit its penetration into cells. Many current studies have reported possible application of aptamers as a treatment or diagnostic tool in viral infections, e.g., HIV (Human Immunodeficiency Virus), HBV (Hepatitis B Virus), HCV (Hepatitis C Virus), SARS (Severe Acute Respiratory Syndrome), H5N1 avian influenza and recently spread Ebola. This review presents current developments of using aptamers in the diagnostics and treatment of viral diseases.
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Thiviyanathan V, Gorenstein DG. Aptamers and the next generation of diagnostic reagents. Proteomics Clin Appl 2014; 6:563-73. [PMID: 23090891 DOI: 10.1002/prca.201200042] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 09/17/2012] [Accepted: 09/20/2012] [Indexed: 01/06/2023]
Abstract
Antibodies have been extensively used as capture and detection reagents in diagnostic applications of proteomics-based technologies. Proteomic assays need high sensitivity and specificity, a wide dynamic range for detection, and accurate, reproducible quantification with small confidence values. However, several inherent limitations of monoclonal antibodies in meeting the emerging challenges of proteomics led to the development of a new class of oligonucleotide-based reagents. Natural and derivatized nucleic acid aptamers are emerging as promising alternatives to monoclonal antibodies. Aptamers can be effectively used to simultaneously detect thousands of proteins in multiplex discovery platforms, where antibodies often fail due to cross-reactivity problems. Through chemical modification, vast range of additional functional groups can be added at any desired position in the oligonucleotide sequence, therefore the best features of small molecule drugs, proteins, and antibodies can be brought together into aptamers, making aptamers the most versatile reagent in proteomics. In this review, we discuss the recent developments in aptamer technology, including new selection methods and the aptamers' application in proteomics.
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Affiliation(s)
- Varatharasa Thiviyanathan
- Centers for Proteomics & Systems Biology, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX, USA
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Aptamer-based therapeutics: new approaches to combat human viral diseases. Pharmaceuticals (Basel) 2013; 6:1507-42. [PMID: 24287493 PMCID: PMC3873675 DOI: 10.3390/ph6121507] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 11/12/2013] [Accepted: 11/15/2013] [Indexed: 12/18/2022] Open
Abstract
Viruses replicate inside the cells of an organism and continuously evolve to contend with an ever-changing environment. Many life-threatening diseases, such as AIDS, SARS, hepatitis and some cancers, are caused by viruses. Because viruses have small genome sizes and high mutability, there is currently a lack of and an urgent need for effective treatment for many viral pathogens. One approach that has recently received much attention is aptamer-based therapeutics. Aptamer technology has high target specificity and versatility, i.e., any viral proteins could potentially be targeted. Consequently, new aptamer-based therapeutics have the potential to lead a revolution in the development of anti-infective drugs. Additionally, aptamers can potentially bind any targets and any pathogen that is theoretically amenable to rapid targeting, making aptamers invaluable tools for treating a wide range of diseases. This review will provide a broad, comprehensive overview of viral therapies that use aptamers. The aptamer selection process will be described, followed by an explanation of the potential for treating virus infection by aptamers. Recent progress and prospective use of aptamers against a large variety of human viruses, such as HIV-1, HCV, HBV, SCoV, Rabies virus, HPV, HSV and influenza virus, with particular focus on clinical development of aptamers will also be described. Finally, we will discuss the challenges of advancing antiviral aptamer therapeutics and prospects for future success.
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Aptamer--nanoparticle-based chemiluminescence for p53 protein. Anal Biochem 2013; 441:73-9. [PMID: 23816877 DOI: 10.1016/j.ab.2013.06.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 06/07/2013] [Accepted: 06/11/2013] [Indexed: 11/24/2022]
Abstract
A simple colorimetric biosensing technique based on the interaction of gold nanoparticles (AuNPs) with the aptamer was developed for detection of p53, a tumor suppressor protein, in the current study. Aggregation of AuNPs was induced by desorption of the p53 binding RNA aptamer from the surface of AuNPs as a result of the aptamer target interaction leading to the color change of AuNPs from red to purple. The detection limit of p53 protein by the colorimetric approach was 0.1 ng/ml after successful optimization of the amount of aptamer, AuNPs, salts, and incubation time. Furthermore, the catalytic activity of the aggregated AuNPs was greatly enhanced by chemiluminescence (CL) reaction, where the detection limit was enhanced to 10 pg/ml with a regression coefficient of R2 = 0.9907. Here the sensitivity was increased by 10-fold compared with the AuNP-based colorimetric method. Hence, the sensitivity of detection was increased by employing CL, by using the catalytic activity of aggregated AuNPs, on the luminol-hydrogen peroxide reaction. Thus, the combination of colorimetric and CL-based aptasensor can be of great advantage in increasing the sensitivity of detection for any target analyte.
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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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Ditzler MA, Lange MJ, Bose D, Bottoms CA, Virkler KF, Sawyer AW, Whatley AS, Spollen W, Givan SA, Burke DH. High-throughput sequence analysis reveals structural diversity and improved potency among RNA inhibitors of HIV reverse transcriptase. Nucleic Acids Res 2012; 41:1873-84. [PMID: 23241386 PMCID: PMC3561961 DOI: 10.1093/nar/gks1190] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Systematic evolution of ligands through exponential enrichment (SELEX) is a well-established method for generating nucleic acid populations that are enriched for specified functions. High-throughput sequencing (HTS) enhances the power of comparative sequence analysis to reveal details of how RNAs within these populations recognize their targets. We used HTS analysis to evaluate RNA populations selected to bind type I human immunodeficiency virus reverse transcriptase (RT). The populations are enriched in RNAs of independent lineages that converge on shared motifs and in clusters of RNAs with nearly identical sequences that share common ancestry. Both of these features informed inferences of the secondary structures of enriched RNAs, their minimal structural requirements and their stabilities in RT-aptamer complexes. Monitoring population dynamics in response to increasing selection pressure revealed RNA inhibitors of RT that are more potent than the previously identified pseudoknots. Improved potency was observed for inhibition of both purified RT in enzymatic assays and viral replication in cell-based assays. Structural and functional details of converged motifs that are obscured by simple consensus descriptions are also revealed by the HTS analysis. The approach presented here can readily be generalized for the efficient and systematic post-SELEX development of aptamers for down-stream applications.
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Affiliation(s)
- Mark A Ditzler
- Molecular Microbiology and Immunology, University of Missouri, Columbia, MO, USA
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Abstract
IMPORTANCE OF THE FIELD Therapeutic aptamers are synthetic, structured oligonucleotides that bind to a very broad range of targets with high affinity and specificity. They are an emerging class of targeting ligand that show great promise for treating a number of diseases. A series of aptamers currently in various stages of clinical development highlights the potential of aptamers for therapeutic applications. AREAS COVERED IN THIS REVIEW This review covers in vitro selection of oligonucleotide ligands, called aptamers, from a combinatorial library using the Systematic Evolution of Ligands by Exponential Enrichment process as well as the other known strategies for finding aptamers against various targets. WHAT THE READER WILL GAIN Readers will gain an understanding of the highly useful strategies for successful aptamer discovery. They may also be able to combine two or more of the presented strategies for their aptamer discovery projects. TAKE HOME MESSAGE Although many processes are available for discovering aptamers, it is not easy to discover an aptamer candidate that is ready to move toward pharmaceutical drug development. It is also apparent that there have been relatively few therapeutic advances and clinical trials undertaken due to the small number of companies that participate in aptamer development.
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Nastasijevic B, Wright BR, Smestad J, Warrington AE, Rodriguez M, Maher LJ. Remyelination induced by a DNA aptamer in a mouse model of multiple sclerosis. PLoS One 2012; 7:e39595. [PMID: 22761835 PMCID: PMC3384608 DOI: 10.1371/journal.pone.0039595] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 05/28/2012] [Indexed: 11/18/2022] Open
Abstract
Multiple sclerosis (MS) is a debilitating inflammatory disease of the central nervous system (CNS) characterized by local destruction of the insulating myelin surrounding neuronal axons. With more than 200 million MS patients worldwide, the absence of treatments that prevent progression or induce repair poses a major challenge. Anti-inflammatory therapies have met with limited success only in preventing relapses. Previous screening of human serum samples revealed natural IgM antibodies that bind oligodendrocytes and promote both cell signaling and remyelination of CNS lesions in an MS model involving chronic infection of susceptible mice by Theiler's encephalomyelitis virus and in the lysolecithin model of focal demyelination. This intriguing result raises the possibility that molecules with binding specificity for oligodendrocytes or myelin components may promote therapeutic remyelination in MS. Because of the size and complexity of IgM antibodies, it is of interest to identify smaller myelin-specific molecules with the ability to promote remyelination in vivo. Here we show that a 40-nucleotide single-stranded DNA aptamer selected for affinity to murine myelin shows this property. This aptamer binds multiple myelin components in vitro. Peritoneal injection of this aptamer results in distribution to CNS tissues and promotes remyelination of CNS lesions in mice infected by Theiler's virus. Interestingly, the selected DNA aptamer contains guanosine-rich sequences predicted to induce folding involving guanosine quartet structures. Relative to monoclonal antibodies, DNA aptamers are small, stable, and non-immunogenic, suggesting new possibilities for MS treatment.
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Affiliation(s)
- Branislav Nastasijevic
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Brent R. Wright
- Departments of Neurology and Immunology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - John Smestad
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Arthur E. Warrington
- Departments of Neurology and Immunology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Moses Rodriguez
- Departments of Neurology and Immunology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
- * E-mail: (LJM); (MR)
| | - L. James Maher
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
- * E-mail: (LJM); (MR)
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Kaur H, Yung LYL. Probing high affinity sequences of DNA aptamer against VEGF165. PLoS One 2012; 7:e31196. [PMID: 22359573 PMCID: PMC3281051 DOI: 10.1371/journal.pone.0031196] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 01/03/2012] [Indexed: 11/19/2022] Open
Abstract
Vascular endothelial growth factor (VEGF165) is a potent angiogenic mitogen commonly overexpressed in cancerous cells. It contains two main binding domains, the receptor-binding domain (RBD) and the heparin-binding domain (HBD). This study attempted to identify the specific sequences of the VEa5 DNA aptamer that exhibit high binding affinity towards the VEGF165 protein by truncating the original VEa5 aptamer into different segments. Using surface plasmon resonance (SPR) spectroscopy for binding affinity analysis, one of the truncated aptamers showed a >200-fold increase in the binding affinity for HBD. This truncated aptamer also exhibited high specificity to HBD with negligible binding affinity for VEGF121, an isoform of VEGF lacking HBD. Exposing colorectal cancer cells to the truncated aptamer sequence further confirmed the binding affinity and specificity of the aptamer to the target VEGF165 protein. Hence, our approach of aptamer truncation can potentially be useful in identifying high affinity aptamer sequences for the biological molecules and targeting them as antagonist for cancer cell detection.
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Affiliation(s)
- Harleen Kaur
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore
| | - Lin-Yue Lanry Yung
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore
- * E-mail:
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Ditzler MA, Bose D, Shkriabai N, Marchand B, Sarafianos SG, Kvaratskhelia M, Burke DH. Broad-spectrum aptamer inhibitors of HIV reverse transcriptase closely mimic natural substrates. Nucleic Acids Res 2011; 39:8237-47. [PMID: 21727088 PMCID: PMC3185408 DOI: 10.1093/nar/gkr381] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A detailed understanding of how aptamers recognize biological binding partners is of considerable importance in the development of oligonucleotide therapeutics. For antiviral nucleic acid aptamers, current models predict a correlation between broad-spectrum inhibition of viral proteins and suppression of emerging viral resistance, but there is little understanding of how aptamer structures contribute to recognition specificity. We previously established that two independent single-stranded DNA aptamers, R1T and RT1t49(−5), are potent inhibitors of reverse transcriptases (RTs) from diverse branches of the primate lentiviral family, including HIV-1, HIV-2 and SIV(cpz). In contrast, class 1 RNA pseudoknots, such as aptamer T1.1, are specific for RTs from only a few viral clades. Here, we map the binding interfaces of complexes formed between RT and aptamers R1T, RT1t49(−5) and T1.1, using mass spectrometry-based protein footprinting of RT and hydroxyl radical footprinting of the aptamers. These complementary methods reveal that the broad-spectrum aptamers make contacts throughout the primer-template binding cleft of RT. The double-stranded stems of these aptamers closely mimic natural substrates near the RNase H domain, while their binding within the polymerase domain significantly differs from RT substrates. These results inform our perspective on how sustained, broad-spectrum inhibition of RT can be achieved by aptamers.
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Affiliation(s)
- Mark A Ditzler
- Molecular Microbiology and Immunology, University of Missouri, Columbia, MO 65211, USA
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Somasunderam A, Thiviyanathan V, Tanaka T, Li X, Neerathilingam M, Lokesh GLR, Mann A, Peng Y, Ferrari M, Klostergaard J, Gorenstein DG. Combinatorial selection of DNA thioaptamers targeted to the HA binding domain of human CD44. Biochemistry 2010; 49:9106-12. [PMID: 20843027 DOI: 10.1021/bi1009503] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
CD44, the primary receptor for hyaluronic acid, plays an important role in tumor growth and metastasis. CD44-hyaluronic acid interactions can be exploited for targeted delivery of anticancer agents specifically to cancer cells. Although various splicing variants of CD44 are expressed on the plasma membrane of cancer cells, the hyaluronic acid binding domain (HABD) is highly conserved among the CD44 splicing variants. Using a novel two-step process, we have identified monothiophosphate-modified aptamers (thioaptamers) that specifically bind to the CD44's HABD with high affinities. Binding affinities of the selected thioaptamers for the HABD were in the range of 180-295 nM, an affinity significantly higher than that of hyaluronic acid (K(d) above the micromolar range). The selected thioaptamers bound to CD44 positive human ovarian cancer cell lines (SKOV3, IGROV, and A2780) but failed to bind the CD44 negative NIH3T3 cell line. Our results indicated that thio substitution at specific positions of the DNA phosphate backbone results in specific and high-affinity binding of thioaptamers to CD44. The selected thioaptamers will be of great interest for further development as a targeting or imaging agent for the delivery of therapeutic payloads for cancer tissues.
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Affiliation(s)
- Anoma Somasunderam
- Institute of Molecular Medicine, University of Texas Health ScienceCenter, Houston, Texas 77030, United States
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Identification of thioaptamer ligand against E-selectin: potential application for inflamed vasculature targeting. PLoS One 2010; 5. [PMID: 20927342 PMCID: PMC2948018 DOI: 10.1371/journal.pone.0013050] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 09/02/2010] [Indexed: 01/16/2023] Open
Abstract
Active targeting of a drug carrier to a specific target site is crucial to provide a safe and efficient delivery of therapeutics and imaging contrast agents. E-selectin expression is induced on the endothelial cell surface of vessels in response to inflammatory stimuli but is absent in the normal vessels. Thus, E-selectin is an attractive molecular target, and high affinity ligands for E-selectin could be powerful tools for the delivery of therapeutics and/or imaging agents to inflamed vessels. In this study, we identified a thiophosphate modified aptamer (thioaptamer, TA) against E-selectin (ESTA-1) by employing a two-step selection strategy: a recombinant protein-based TA binding selection from a combinatorial library followed by a cell-based TA binding selection using E-selectin expressing human microvascular endothelial cells. ESTA-1 selectively bound to E-selectin with nanomolar binding affinity (KD = 47 nM) while exhibiting minimal cross reactivity to P- and L-selectin. Furthermore, ESTA-1 binding to E-selectin on the endothelial cells markedly antagonized the adhesion (over 75% inhibition) of sLex positive HL-60 cells at nanomolar concentration. ESTA-1 also bound specifically to the inflamed tumor-associated vasculature of human carcinomas derived from breast, ovarian, and skin but not to normal organs, and this binding was highly associated with the E-selectin expression level. Similarly, intravenously injected ESTA-1 demonstrated distinct binding to the tumor vasculature in a breast cancer xenograft model. Together, our data substantiates the discovery of a thioaptamer (ESTA-1) that binds to E-selectin with high affinity and specificity, thereby highlighting the potential application of ESTA-1 for E-selectin targeted delivery.
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Adamson CS, Freed EO. Novel approaches to inhibiting HIV-1 replication. Antiviral Res 2010; 85:119-41. [PMID: 19782103 PMCID: PMC2815006 DOI: 10.1016/j.antiviral.2009.09.009] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 09/09/2009] [Accepted: 09/12/2009] [Indexed: 01/17/2023]
Abstract
Considerable success has been achieved in the treatment of HIV-1 infection, and more than two-dozen antiretroviral drugs are available targeting several distinct steps in the viral replication cycle. However, resistance to these compounds emerges readily, even in the context of combination therapy. Drug toxicity, adverse drug-drug interactions, and accompanying poor patient adherence can also lead to treatment failure. These considerations make continued development of novel antiretroviral therapeutics necessary. In this article, we highlight a number of steps in the HIV-1 replication cycle that represent promising targets for drug discovery. These include lipid raft microdomains, the RNase H activity of the viral enzyme reverse transcriptase, uncoating of the viral core, host cell machinery involved in the integration of the viral DNA into host cell chromatin, virus assembly, maturation, and budding, and the functions of several viral accessory proteins. We discuss the relevant molecular and cell biology, and describe progress to date in developing inhibitors against these novel targets. This article forms part of a special issue of Antiviral Research marking the 25th anniversary of antiretroviral drug discovery and development, Vol 85, issue 1, 2010.
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Affiliation(s)
- Catherine S. Adamson
- Virus-Cell Interaction Section, HIV Drug Resistance Program, National Cancer Institute at Frederick, Maryland, 21702-1201
| | - Eric O. Freed
- Virus-Cell Interaction Section, HIV Drug Resistance Program, National Cancer Institute at Frederick, Maryland, 21702-1201
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Loakes D, Holliger P. Polymerase engineering: towards the encoded synthesis of unnatural biopolymers. Chem Commun (Camb) 2009:4619-31. [PMID: 19641798 DOI: 10.1039/b903307f] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
DNA is not only a repository of genetic information for life, it is also a unique polymer with remarkable properties: it associates according to well-defined rules, it can be assembled into diverse nanostructures of defined geometry, it can be evolved to bind ligands and catalyse chemical reactions and it can serve as a supramolecular scaffold to arrange chemical groups in space. However, its chemical makeup is rather uniform and the physicochemical properties of the four canonical bases only span a narrow range. Much wider chemical diversity is accessible through solid-phase synthesis but oligomers are limited to <100 nucleotides and variations in chemistry can usually not be replicated and thus are not amenable to evolution. Recent advances in nucleic acid chemistry and polymerase engineering promise to bring the synthesis, replication and ultimately evolution of nucleic acid polymers with greatly expanded chemical diversity within our reach.
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Affiliation(s)
- David Loakes
- Medical Research Council, Laboratory of Molecular Biology, Hills Road, Cambridge, Cambridgeshire, UKCB2 0QH
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Michalowski D, Chitima-Matsiga R, Held DM, Burke DH. Novel bimodular DNA aptamers with guanosine quadruplexes inhibit phylogenetically diverse HIV-1 reverse transcriptases. Nucleic Acids Res 2008; 36:7124-35. [PMID: 18996899 PMCID: PMC2602765 DOI: 10.1093/nar/gkn891] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
DNA aptamers RT5, RT6 and RT47 form a group of related sequences that inhibit HIV-1 reverse transcriptase (RT). The essential inhibitory structure is identified here as bimodular, with a 5' stem-loop module physically connected to a 3'-guanosine quadruplex module. The stem-loop tolerates considerable sequence plasticity. Connections between the guanosine triplets in the quadruplex could be simplified to a single nucleotide or a nonnucleic acid linker, such as hexaethylene glycol. All 12 quadruplex guanosines are required in an aptamer retaining most of the original loop sequence from RT6; only 11 are required for aptamer R1T (single T residue in intra-quadruplex loops). Circular dichroism (CD) spectroscopy gave ellipticity minima and maxima at 240 nm and 264 nm, indicating a parallel arrangement of the quadruplex strands. The simplified aptamers displayed increased overall stability. An aptamer carrying the original intra-quadruplex loops from RT6 inhibited RT in K(+) buffers but not in Na(+) buffers and displayed significant CD spectral broadening in Na(+) buffers, while R1T inhibited RT in both buffers and displayed less broadening in Na(+) buffers. The bimodular ssDNA aptamers inhibited RT from diverse primate lentiviruses with low nM IC(50) values. These data provide insight into the requirements for broad-spectrum RT inhibition by nucleic acid aptamers.
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Affiliation(s)
- Daniel Michalowski
- Department of Molecular Microbiology & Immunology, University of Missouri School of Medicine, Columbia, MO 65211, USA
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Jochmans D. Novel HIV-1 reverse transcriptase inhibitors. Virus Res 2008; 134:171-85. [PMID: 18308412 DOI: 10.1016/j.virusres.2008.01.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 01/07/2008] [Accepted: 01/08/2008] [Indexed: 10/22/2022]
Abstract
HIV-1 reverse transcriptase (RT) was the first viral enzyme to be targeted by anti-HIV drugs. Despite 20 years of experience with RT inhibitors, new ways to inhibit this target and address viral resistance continue to emerge. In both licensed RT inhibitor classes, nucleosides (NRTIs) and non-nucleosides (NNRTIs), compounds with better resistance, pharmacokinetic and toxicity profiles are being developed. Second-generation NNRTIs active against HIV-1 strains resistant to current NNRTIs are being clinically evaluated. Beyond the classical NRTIs, nucleoside analogs that are no longer obligate chain terminators but nevertheless impede reverse transcription or even lead to viral ablation after several replication cycles, are being studied. RT inhibitor research has also yielded additional mechanisms to block RT. Driven by new insights the RNase H field remains in evolution. In addition, the binding of both substrates (deoxynucleotide and primer/template) to RT is now subject to competition by novel inhibitors. Further development of aptamers bears promise for gene therapy but perhaps more importantly, reveals additional new platforms for the development of small-molecule RT inhibitors. This promising research provides much optimism that RT inhibitors will continue to evolve with subsequent clinical benefit.
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Affiliation(s)
- Dirk Jochmans
- Tibotec BVBA, Gen De Wittelaan L 11B 3, 2800 Mechelen, Belgium.
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Kissel JD, Held DM, Hardy RW, Burke DH. Active site binding and sequence requirements for inhibition of HIV-1 reverse transcriptase by the RT1 family of single-stranded DNA aptamers. Nucleic Acids Res 2007; 35:5039-50. [PMID: 17644816 PMCID: PMC1976467 DOI: 10.1093/nar/gkm420] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Nucleic acid aptamers can potentially be developed as broad-spectrum antiviral agents. Single-stranded DNA (ssDNA) aptamer RT1t49 inhibits reverse transcriptases (RT) from HIV-1 and diverse lentiviral subtypes with low nanomolar values of Kd and IC50. To dissect the structural requirements for inhibition, RT-catalyzed DNA polymerization was measured in the presence of RT1t49 variants. Three structural domains were found to be essential for RT inhibition by RT1t49: a 5′ stem (stem I), a connector and a 3′ stem (stem II) capable of forming multiple secondary structures. Stem I tolerates considerable sequence plasticity, suggesting that it is recognized by RT more by structure than by sequence-specific contacts. Truncating five nucleotides from the 3′ end prevents formation of the most stable stem II structure, yet has little effect on IC50 across diverse HIV-1, HIV-2 and SIVCPZ RT. When bound to wild-type RT or an RNase H active site mutant, site-specifically generated hydroxyl radicals cleave after nucleotide A32. Cleavage is eliminated by either of two polymerase (pol)-active site mutants, strongly suggesting that A32 lies within the RT pol-active site. These data suggest a model of ssDNA aptamer–RT interactions and provide an improved molecular understanding of a potent, broad-spectrum ssDNA aptamer.
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Affiliation(s)
- Jay D. Kissel
- Department of Biology, Indiana University, Bloomington, IN 47405, Biosciences Division, SRI International, Menlo Park, CA 94025 and Department of Molecular Microbiology & Immunology and Department of Biochemistry, 471h Life Sciences Center, University of Missouri School of Medicine, Columbia, MO 65211, USA
| | - Daniel M. Held
- Department of Biology, Indiana University, Bloomington, IN 47405, Biosciences Division, SRI International, Menlo Park, CA 94025 and Department of Molecular Microbiology & Immunology and Department of Biochemistry, 471h Life Sciences Center, University of Missouri School of Medicine, Columbia, MO 65211, USA
| | - Richard W. Hardy
- Department of Biology, Indiana University, Bloomington, IN 47405, Biosciences Division, SRI International, Menlo Park, CA 94025 and Department of Molecular Microbiology & Immunology and Department of Biochemistry, 471h Life Sciences Center, University of Missouri School of Medicine, Columbia, MO 65211, USA
| | - Donald H. Burke
- Department of Biology, Indiana University, Bloomington, IN 47405, Biosciences Division, SRI International, Menlo Park, CA 94025 and Department of Molecular Microbiology & Immunology and Department of Biochemistry, 471h Life Sciences Center, University of Missouri School of Medicine, Columbia, MO 65211, USA
- *To whom correspondence should be addressed.(573) 884 1316(573) 884 9676
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Abstract
Aptamers are oligonucleotides evolved in vitro or in nature to bind target ligands with high affinity and specificity. They are emerging as powerful tools in the fields of therapeutics, drug development, target validation and diagnostics. Aptamers are attractive alternatives to antibody- and small-molecule-based therapeutics owing to their stability, low toxicity, low immunogenicity and improved safety. With the recent approval of the first aptamer drug Macugen by the US FDA, there is great impetus to develop therapeutic aptamers that can target a wide array of disease states. The recent demonstration that aptamer activity can be reversed by the administration of a simple antidote greatly enhances the potential value of aptamers as therapeutic agents.
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Affiliation(s)
- N S Que-Gewirth
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
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Thiviyanathan V, Somasunderam AD, Gorenstein DG. Combinatorial selection and delivery of thioaptamers. Biochem Soc Trans 2007; 35:50-2. [PMID: 17233599 DOI: 10.1042/bst0350050] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Oligonucleotide-based agents are emerging as potential therapeutic agents that can be attractive alternatives for the small-molecule chemical drugs. Monothiophosphate-backbone-modified DNA aptamers (thioaptamers) that specifically and tightly bind to the RNase H domain of the HIV RT (reverse transcriptase) have been isolated from nucleic acid libraries using combinatorial selection methods. The selected thioaptamer inhibited RNase H activity of the HIV RT in in vitro studies. In cell cultures, the transfected thioaptamer markedly reduced HIV production in a dose-dependent manner. Gel electrophoretic mobility-shift assays and NMR spectroscopy showed that the selected thioaptamer binds to the isolated RNase H domain, but did not bind to a structurally similar RNase H from Escherichia coli. In cell cultures, the transfected thioaptamer showed a dose-dependent inhibition of HIV replication, with a maximal inhibition of 83%. Using various liposome-delivery agents, the DNA thioaptamer was transfected into HIV-infected astrocytoma adherent cells with greater than 70% efficiency.
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Affiliation(s)
- V Thiviyanathan
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555-1157, USA.
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Kissel JD, Held DM, Hardy RW, Burke DH. Single-stranded DNA aptamer RT1t49 inhibits RT polymerase and RNase H functions of HIV type 1, HIV type 2, and SIVCPZ RTs. AIDS Res Hum Retroviruses 2007; 23:699-708. [PMID: 17530996 DOI: 10.1089/aid.2006.0262] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Natural and selected resistance of HIV-1 to current anti-HIV drugs continues to pose serious problems to the development of HIV-1 antivirals. The viral reverse transcriptase (RT) is a proven therapeutic target. Single-stranded RNA and DNA (ssRNA and ssDNA) aptamers have been selected that specifically and potently inhibit RT function. In particular, the ssDNA aptamer RT1t49 was previously selected to recognize the RT from a subtype B strain of HIV-1 and binds with a reported K(d) of 4 nM. In the present work, we show that RT1t49 inhibits recombinant RT cloned from diverse branches of the primate lentiviral family. Aptamer concentrations required for half-maximal inhibition of all HIV-1, HIV-2, and SIV(CPZ) RTs assayed were in the low-to mid-nanomolar range for both polymerase and RNase H activities. Using pre-steady-state and order-of-addition kinetic analyses, we also established that this ssDNA aptamer competes with primer-template for access to RT, and that addition of a nucleoside analog RT inhibitor (NRTI) to the in vitro reaction enhanced the overall effectiveness of both drugs, while nonnucleoside analog RT inhibitors (NNRTIs) exhibited simple additivity. This is the first demonstration of universal inhibition of HIV and SIV(cpz) RTs by a nucleic acid aptamer and supports previous reports suggesting that resistance to RT1t49 may be exceptionally infrequent.
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Affiliation(s)
- Jay D Kissel
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
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Wang H, Yang X, Bowick GC, Herzog NK, Luxon BA, Lomas LO, Gorenstein DG. Identification of proteins bound to a thioaptamer probe on a proteomics array. Biochem Biophys Res Commun 2006; 347:586-93. [PMID: 16842751 DOI: 10.1016/j.bbrc.2006.06.132] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Accepted: 06/16/2006] [Indexed: 10/24/2022]
Abstract
A rapid method to screen and identify unknown bound proteins to specific nucleic acid probes anchored on ProteinChip array surfaces from crude biological samples has been developed in this paper. It was demonstrated with screening specific binding proteins from LPS-stimulated mouse 70Z/3 pre-B cell nuclear extracts by direct coupling of thioaptamer XBY-S2 to the pre-activated ProteinChip array surfaces. With pre-fractionation of crude nuclear extracts by ion exchange method, specific "on-chip" captured proteins have been obtained that were pure enough to do "on-chip" digestion and the subsequent identification of the "on-chip" bound proteins by microsequencing of the trypsin digested peptide fragments through tandem MS. Five mouse heterogeneous nuclear ribonucleoproteins (hnRNPs) A1, A2/B1, A3, A/B, and D0 were identified. To verify those bound hnRNPs, a novel thioaptamer/antibody sandwich assay provides highly sensitive and selective identification of proteins on ProteinChip arrays.
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Affiliation(s)
- He Wang
- Ciphergen, Inc., Fremont, CA 94555, USA
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39
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Held DM, Kissel JD, Saran D, Michalowski D, Burke DH. Differential susceptibility of HIV-1 reverse transcriptase to inhibition by RNA aptamers in enzymatic reactions monitoring specific steps during genome replication. J Biol Chem 2006; 281:25712-22. [PMID: 16798747 DOI: 10.1074/jbc.m604460200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nucleic acid aptamers to HIV-1 reverse transcriptase (RT) are potent inhibitors of DNA polymerase function in vitro, and they have been shown to inhibit viral replication when expressed in cultured T-lymphoid lines. We monitored RT inhibition by five RNA pseudoknot RNA aptamers in a series of biochemical assays designed to mimic discrete steps of viral reverse transcription. Our results demonstrate potent aptamer inhibition (IC50 values in the low nanomolar range) of all RT functions assayed, including RNA- and DNA-primed DNA polymerization, strand displacement synthesis, and polymerase-independent RNase H activity. Additionally, we observe differences in the time dependence of aptamer inhibition. Polymerase-independent RNase H activity is the most resistant to long term aptamer suppression, and RNA-dependent DNA polymerization is the most susceptible. Finally, when DNA polymerization was monitored in the presence of an RNA aptamer in combination with each of four different small molecule inhibitors, significant synergy was observed between the aptamer and the two nucleoside analog RT inhibitors (azidothymidine triphosphate or ddCTP), whereas two non-nucleoside analog RT inhibitors showed either weak synergy (efavirenz) or antagonism (nevirapine). Together, these results support a model wherein aptamers suppress viral replication by cumulative inhibition of RT at every stage of genome replication.
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Affiliation(s)
- Daniel M Held
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
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Ferguson MR, Rojo DR, Somasunderam A, Thiviyanathan V, Ridley BD, Yang X, Gorenstein DG. Delivery of double-stranded DNA thioaptamers into HIV-1 infected cells for antiviral activity. Biochem Biophys Res Commun 2006; 344:792-7. [PMID: 16631118 DOI: 10.1016/j.bbrc.2006.03.201] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Accepted: 03/28/2006] [Indexed: 11/24/2022]
Abstract
Oligonucleotide agents (ODN) are emerging as attractive alternatives to chemical drugs. However, the clinical use of ODNs as therapeutics has been hindered by their susceptibility to degradation by cellular enzymes and their limited ability to penetrate intact cells. We have used various liposome-mediated transfection agents, for the in vitro delivery of DNA thioaptamers into U373-MAGI-CCR5 cells. Our lead thioaptamer, R12-2, targets the RNase H domain of the HIV-1 reverse transcriptase (RT) and inhibits viral infection in U373-MAGI-CCR5 cells. R12-2, a 62-base-pair, double-stranded DNA molecule with a monothio-phosphate modified backbone, was selected through a novel combinatorial selection method. We studied the use of oligofectamine (OF), TFX-20, Transmessenger (TM), and Gene Jammer (GJ) for transfection of the thio-modified DNA aptamers. OF-transfected U373-MAGI-CCR5 cells resulted in 68% inhibition of HIV infection in the treated cells compared to the untreated control. Inhibition was observed in a dose-dependent manner with maximal inhibition of 83%. In this report, we demonstrate that monothioate-modified DNA duplex oligonucleotides can be efficiently delivered into cells by liposome-based transfection agents to inhibit HIV replication.
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Affiliation(s)
- Monique R Ferguson
- Division of Infectious Diseases, Department of Internal Medicine, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.
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