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Thevendran R, Rogini S, Leighton G, Mutombwera A, Shigdar S, Tang TH, Citartan M. The Diagnostic Potential of RNA Aptamers against the NS1 Protein of Dengue Virus Serotype 2. BIOLOGY 2023; 12:biology12050722. [PMID: 37237536 DOI: 10.3390/biology12050722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 03/24/2023] [Accepted: 03/30/2023] [Indexed: 05/28/2023]
Abstract
Dengue infection, caused by the dengue virus, is a global threat which requires immediate attention and appropriate disease management. The current diagnosis of dengue infection is largely based on viral isolation, RT-PCR and serology-based detection, which are time-consuming and expensive, and require trained personnel. For early diagnosis of dengue, the direct detection of a dengue antigenic target is efficacious, and one such target is NS1. NS1-based detection is primarily antibody-centric and is beset by drawbacks pertaining to antibodies such as the high cost of synthesis and large batch-to-batch variation. Aptamers are potential surrogates of antibodies and are much cheaper, without exhibiting batch-to-batch variation. Given these advantages, we sought to isolate RNA aptamers against the NS1 protein of dengue virus serotype 2. A total of 11 cycles of SELEX were carried out, resulting in two potent aptamers, DENV-3 and DENV-6, with dissociation constant values estimated at 37.57 ± 10.34 nM and 41.40 ± 9.29 nM, respectively. These aptamers can be further miniaturized to TDENV-3 and TDENV-6a with an increased LOD upon their usage in direct ELASA. Moreover, these truncated aptamers are highly specific against the dengue NS1 while showing no cross-reactivity against the NS1 of the Zika virus, the E2 protein of the Chikungunya virus or the LipL32 protein of Leptospira, with target selectivity retained even in human serum. The usage of TDENV-3 as the capturing probe and TDENV-6a as the detection probe underpinned the development of an aptamer-based sandwich ELASA for the detection of dengue NS1. The sensitivity of the sandwich ELASA was further improved with the stabilization of the truncated aptamers and the repeated incubation strategy, which enabled a LOD of 2 nM when used with the target NS1 spiked in human serum diluted at 1:2000.
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Affiliation(s)
- Ramesh Thevendran
- Department of Biomedical Science, Advanced Medical & Dental Institute (AMDI), University Sains Malaysia, Bertam, Kepala Batas 13200, Malaysia
| | - Sivalingam Rogini
- Department of Biomedical Science, Advanced Medical & Dental Institute (AMDI), University Sains Malaysia, Bertam, Kepala Batas 13200, Malaysia
| | - Glenn Leighton
- Hutano Diagnostics Ltd. BioEscalator, Innovation Building, Old Road Campus, University of Oxford, Roosevelt Drive, Oxford OX3 7FZ, UK
| | - Atherton Mutombwera
- Hutano Diagnostics Ltd. BioEscalator, Innovation Building, Old Road Campus, University of Oxford, Roosevelt Drive, Oxford OX3 7FZ, UK
| | - Sarah Shigdar
- School of Medicine, Deakin University, Geelong, VIC 3217, Australia
- Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Deakin University, Geelong, VIC 3220, Australia
| | - Thean-Hock Tang
- Department of Biomedical Science, Advanced Medical & Dental Institute (AMDI), University Sains Malaysia, Bertam, Kepala Batas 13200, Malaysia
| | - Marimuthu Citartan
- Department of Biomedical Science, Advanced Medical & Dental Institute (AMDI), University Sains Malaysia, Bertam, Kepala Batas 13200, Malaysia
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Pan Q, Law COK, Yung MMH, Han KC, Pon YL, Lau TCK. Novel RNA aptamers targeting gastrointestinal cancer biomarkers CEA, CA50 and CA72-4 with superior affinity and specificity. PLoS One 2018; 13:e0198980. [PMID: 30303958 PMCID: PMC6179186 DOI: 10.1371/journal.pone.0198980] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 09/21/2018] [Indexed: 11/18/2022] Open
Abstract
Gastric cancer is the third most common cause of death from cancer in the world and it remains difficult to cure in Western countries, primarily because most patients present with advanced disease. Currently, CEA, CA50 and CA72-4 are commonly used as tumor markers for gastric cancer by immunoassays. However, the drawback and conundrum of immunoassay are the unceasing problem in standardization of quality of antibodies and time/effort for the intensive production. Therefore, there is an urgent need for the development of a standardized assay to detect gastric cancer at the early stage. Aptamers are DNA or RNA oligonucleotides with structural domain which recognize ligands such as proteins with superior affinity and specificity when compared to antibodies. In this study, SELEX (Systematic Evolution of Ligands by Exponential enrichment) technique was adopted to screen a random 30mer RNA library for aptamers targeting CEA, CA50 and CA72-4 respectively. Combined with high-throughput sequencing, we identified 6 aptamers which specifically target for these three biomarkers of gastrointestinal cancer. Intriguingly, the predicted secondary structures of RNA aptamers from each antigen showed significant structural similarity, suggesting the structural recognition between the aptamers and the antigens. Moreover, we determined the dissociation constants of all the aptamers to their corresponding antigens by fluorescence spectroscopy, which further demonstrated high affinities between the aptamers and the antigens. In addition, immunostaining of gastric adenocarcinoma cell line AGS using CEA Aptamer probe showed positive fluorescent signal which proves the potential of the aptamer as a detection tool for gastric cancer. Furthermore, substantially decreased cell viability and growth were observed when human colorectal cell line LS-174T was transfected with each individual aptamers. Taking together, these novel RNA aptamers targeting gastrointestinal cancer biomarker CEA, CA50 and CA72-4 will aid further development and standardization of clinical diagnostic method with better sensitivity and specificity, and potentially future therapeutics development of gastric cancer.
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Affiliation(s)
- Qing Pan
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong Special Administrative Region, China
| | - Carmen O. K. Law
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong Special Administrative Region, China
| | - Mingo M. H. Yung
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong Special Administrative Region, China
| | - K. C. Han
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong Special Administrative Region, China
| | - Yuen Lam Pon
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong Special Administrative Region, China
| | - Terrence Chi Kong Lau
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong Special Administrative Region, China
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Yan A, Levy M. Cell internalization SELEX: in vitro selection for molecules that internalize into cells. Methods Mol Biol 2014; 1103:241-65. [PMID: 24318899 DOI: 10.1007/978-1-62703-730-3_18] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Aptamer technology allows for the selection of nucleic acids that can bind to and enter cells. By establishing conditions during the selection that eliminate cell-surface binders as well as non-internalizing RNAs, only extremely tightly bound aptamers or aptamers that have internalized are recovered. We describe a general scheme for selecting RNA molecules that are capable of internalizing into cells and discuss the factors that can affect a successful selection. Much like standard cell-surface selections, these types of selections should be possible independent of detailed knowledge of the cell surface.
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Affiliation(s)
- Amy Yan
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA
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Challenges and opportunities for small molecule aptamer development. J Nucleic Acids 2012; 2012:748913. [PMID: 23150810 PMCID: PMC3488411 DOI: 10.1155/2012/748913] [Citation(s) in RCA: 286] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 09/08/2012] [Indexed: 12/14/2022] Open
Abstract
Aptamers are single-stranded oligonucleotides that bind to targets with high affinity and selectivity. Their use as molecular recognition elements has emerged as a viable approach for biosensing, diagnostics, and therapeutics. Despite this potential, relatively few aptamers exist that bind to small molecules. Small molecules are important targets for investigation due to their diverse biological functions as well as their clinical and commercial uses. Novel, effective molecular recognition probes for these compounds are therefore of great interest. This paper will highlight the technical challenges of aptamer development for small molecule targets, as well as the opportunities that exist for their application in biosensing and chemical biology.
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Abstract
Aptamers are single-stranded oligonucleotides that bind to targets with high affinity and selectivity. Their use as molecular recognition elements has emerged as a viable approach for biosensing, diagnostics, and therapeutics. Despite this potential, relatively few aptamers exist that bind to small molecules. Small molecules are important targets for investigation due to their diverse biological functions as well as their clinical and commercial uses. Novel, effective molecular recognition probes for these compounds are therefore of great interest. This paper will highlight the technical challenges of aptamer development for small molecule targets, as well as the opportunities that exist for their application in biosensing and chemical biology.
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Dausse E, Taouji S, Evadé L, Di Primo C, Chevet E, Toulmé JJ. HAPIscreen, a method for high-throughput aptamer identification. J Nanobiotechnology 2011; 9:25. [PMID: 21639912 PMCID: PMC3127992 DOI: 10.1186/1477-3155-9-25] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Accepted: 06/03/2011] [Indexed: 01/24/2023] Open
Abstract
Background Aptamers are oligonucleotides displaying specific binding properties for a predetermined target. They are selected from libraries of randomly synthesized candidates through an in vitro selection process termed SELEX (Systematic Evolution of Ligands by EXponential enrichment) alternating selection and amplification steps. SELEX is followed by cloning and sequencing of the enriched pool of oligonucleotides to enable comparison of the selected sequences. The most represented candidates are then synthesized and their binding properties are individually evaluated thus leading to the identification of aptamers. These post-selection steps are time consuming and introduce a bias to the expense of poorly amplified binders that might be of high affinity and are consequently underrepresented. A method that would circumvent these limitations would be highly valuable. Results We describe a novel homogeneous solution-based method for screening large populations of oligonucleotide candidates generated from SELEX. This approach, based on the AlphaScreen® technology, is carried out on the exclusive basis of the binding properties of the selected candidates without the needs of performing a priori sequencing. It therefore enables the functional identification of high affinity aptamers. We validated the HAPIscreen (High throughput APtamer Identification screen) methodology using aptamers targeted to RNA hairpins, previously identified in our laboratory. We then screened pools of candidates issued from SELEX rounds in a 384 well microplate format and identify new RNA aptamers to pre-microRNAs. Conclusions HAPIscreen, an Alphascreen®-based methodology for the identification of aptamers is faster and less biased than current procedures based on sequence comparison of selected oligonucleotides and sampling binding properties of few individuals. Moreover this methodology allows for screening larger number of candidates. Used here for selecting anti-premiR aptamers, HAPIscreen can be adapted to any type of tagged target and is fully amenable to automation.
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Affiliation(s)
- Eric Dausse
- Inserm U869, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33706 Pessac, France
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