1
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Chandy SK, Raghavachari K. MIM-ML: A Novel Quantum Chemical Fragment-Based Random Forest Model for Accurate Prediction of NMR Chemical Shifts of Nucleic Acids. J Chem Theory Comput 2023; 19:6632-6642. [PMID: 37703522 DOI: 10.1021/acs.jctc.3c00563] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
We developed a random forest machine learning (ML) model for the prediction of 1H and 13C NMR chemical shifts of nucleic acids. Our ML model is trained entirely on reproducing computed chemical shifts obtained previously on 10 nucleic acids using a Molecules-in-Molecules (MIM) fragment-based density functional theory (DFT) protocol including microsolvation effects. Our ML model includes structural descriptors as well as electronic descriptors from an inexpensive low-level semiempirical calculation (GFN2-xTB) and trained on a relatively small number of DFT chemical shifts (2080 1H chemical shifts and 1780 13C chemical shifts on the 10 nucleic acids). The ML model is then used to make chemical shift predictions on 8 new nucleic acids ranging in size from 600 to 900 atoms and compared directly to experimental data. Though no experimental data was used in the training, the performance of our model is excellent (mean absolute deviation of 0.34 ppm for 1H chemical shifts and 2.52 ppm for 13C chemical shifts for the test set), despite having some nonstandard structures. A simple analysis suggests that both structural and electronic descriptors are critical for achieving reliable predictions. This is the first attempt to combine ML from fragment-based DFT calculations to predict experimental chemical shifts accurately, making the MIM-ML model a valuable tool for NMR predictions of nucleic acids.
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Affiliation(s)
- Sruthy K Chandy
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Krishnan Raghavachari
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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2
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Chen Z, Luo H, Gubu A, Yu S, Zhang H, Dai H, Zhang Y, Zhang B, Ma Y, Lu A, Zhang G. Chemically modified aptamers for improving binding affinity to the target proteins via enhanced non-covalent bonding. Front Cell Dev Biol 2023; 11:1091809. [PMID: 36910146 PMCID: PMC9996316 DOI: 10.3389/fcell.2023.1091809] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 02/15/2023] [Indexed: 02/25/2023] Open
Abstract
Nucleic acid aptamers are ssDNA or ssRNA fragments that specifically recognize targets. However, the pharmacodynamic properties of natural aptamers consisting of 4 naturally occurring nucleosides (A, G, C, T/U) are generally restricted for inferior binding affinity than the cognate antibodies. The development of high-affinity modification strategies has attracted extensive attention in aptamer applications. Chemically modified aptamers with stable three-dimensional shapes can tightly interact with the target proteins via enhanced non-covalent bonding, possibly resulting in hundreds of affinity enhancements. This review overviewed high-affinity modification strategies used in aptamers, including nucleobase modifications, fluorine modifications (2'-fluoro nucleic acid, 2'-fluoro arabino nucleic acid, 2',2'-difluoro nucleic acid), structural alteration modifications (locked nucleic acid, unlocked nucleic acid), phosphate modifications (phosphorothioates, phosphorodithioates), and extended alphabets. The review emphasized how these high-affinity modifications function in effect as the interactions with target proteins, thereby refining the pharmacodynamic properties of aptamers.
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Affiliation(s)
- Zefeng Chen
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Hang Luo
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Amu Gubu
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Aptacure Therapeutics Limited, Kowloon, Hong Kong SAR, China
| | - Sifan Yu
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Huarui Zhang
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Hong Dai
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Yihao Zhang
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Baoting Zhang
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Yuan Ma
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Precision Medicine and Innovative Drug Discovery, HKBU Institute for Research and Continuing Education, Shenzhen, Hong Kong SAR, China
| | - Aiping Lu
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Precision Medicine and Innovative Drug Discovery, HKBU Institute for Research and Continuing Education, Shenzhen, Hong Kong SAR, China
| | - Ge Zhang
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Precision Medicine and Innovative Drug Discovery, HKBU Institute for Research and Continuing Education, Shenzhen, Hong Kong SAR, China
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3
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Oliveira R, Pinho E, Sousa AL, DeStefano JJ, Azevedo NF, Almeida C. Improving aptamer performance with nucleic acid mimics: de novo and post-SELEX approaches. Trends Biotechnol 2021; 40:549-563. [PMID: 34756455 DOI: 10.1016/j.tibtech.2021.09.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 09/29/2021] [Accepted: 09/29/2021] [Indexed: 12/12/2022]
Abstract
Aptamers are structural single-stranded oligonucleotides generated in vitro to bind to a specific target molecule. Aptamers' versatility can be enhanced with nucleic acid mimics (NAMs) during or after a selection process, also known as systematic evolution of ligands by exponential enrichment (SELEX). We address advantages and limitations of the technologies used to generate NAM aptamers, especially the applicability of existing engineered polymerases to replicate NAMs and methodologies to improve aptamers after SELEX. We also discuss the limitations of existing methods for sequencing NAM sequences and bioinformatic tools to predict NAM aptamer structures. As a conclusion, we suggest that NAM aptamers might successfully compete with molecular tools based on proteins such as antibodies for future application.
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Affiliation(s)
- Ricardo Oliveira
- INIAV - National Institute for Agrarian and Veterinarian Research, Rua dos Lagidos, 4485-655 Vairão, Vila do Conde, Portugal; LEPABE - Laboratory for Process Engineering, Environment, Biotechnology, and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Eva Pinho
- INIAV - National Institute for Agrarian and Veterinarian Research, Rua dos Lagidos, 4485-655 Vairão, Vila do Conde, Portugal
| | - Ana Luísa Sousa
- INIAV - National Institute for Agrarian and Veterinarian Research, Rua dos Lagidos, 4485-655 Vairão, Vila do Conde, Portugal; LEPABE - Laboratory for Process Engineering, Environment, Biotechnology, and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Jeffrey J DeStefano
- Cell Biology and Molecular Genetics, Bioscience Research Building, University of Maryland, College Park, MD 20742, USA
| | - Nuno Filipe Azevedo
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology, and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Carina Almeida
- INIAV - National Institute for Agrarian and Veterinarian Research, Rua dos Lagidos, 4485-655 Vairão, Vila do Conde, Portugal; LEPABE - Laboratory for Process Engineering, Environment, Biotechnology, and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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4
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Amero P, Lokesh GLR, Chaudhari RR, Cardenas-Zuniga R, Schubert T, Attia YM, Montalvo-Gonzalez E, Elsayed AM, Ivan C, Wang Z, Cristini V, Franciscis VD, Zhang S, Volk DE, Mitra R, Rodriguez-Aguayo C, Sood AK, Lopez-Berestein G. Conversion of RNA Aptamer into Modified DNA Aptamers Provides for Prolonged Stability and Enhanced Antitumor Activity. J Am Chem Soc 2021; 143:7655-7670. [PMID: 33988982 DOI: 10.1021/jacs.9b10460] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Aptamers, synthetic single-strand oligonucleotides that are similar in function to antibodies, are promising as therapeutics because of their minimal side effects. However, the stability and bioavailability of the aptamers pose a challenge. We developed aptamers converted from RNA aptamer to modified DNA aptamers that target phospho-AXL with improved stability and bioavailability. On the basis of the comparative analysis of a library of 17 converted modified DNA aptamers, we selected aptamer candidates, GLB-G25 and GLB-A04, that exhibited the highest bioavailability, stability, and robust antitumor effect in in vitro experiments. Backbone modifications such as thiophosphate or dithiophosphate and a covalent modification of the 5'-end of the aptamer with polyethylene glycol optimized the pharmacokinetic properties, improved the stability of the aptamers in vivo by reducing nuclease hydrolysis and renal clearance, and achieved high and sustained inhibition of AXL at a very low dose. Treatment with these modified aptamers in ovarian cancer orthotopic mouse models significantly reduced tumor growth and the number of metastases. This effective silencing of the phospho-AXL target thus demonstrated that aptamer specificity and bioavailability can be improved by the chemical modification of existing aptamers for phospho-AXL. These results lay the foundation for the translation of these aptamer candidates and companion biomarkers to the clinic.
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Affiliation(s)
- Paola Amero
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - 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, Texas 77030, United States
| | - Rajan R Chaudhari
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Roberto Cardenas-Zuniga
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | | | - Yasmin M Attia
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States.,Pharmacology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Kasr Al Eini Street, Fom El Khalig, Cairo 11796, Egypt
| | - Efigenia Montalvo-Gonzalez
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States.,Integral Laboratory of Food Research, Technological Institute of Tepic, Avenue Tecnologico 2595, 63175 Tepic, Nayarit Mexico
| | - Abdelrahman M Elsayed
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States.,Department of Pharmacology and Toxicology, Faculty of Pharmacy, Al-Azhar University, Cairo 11675, Egypt
| | - Cristina Ivan
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Zhihui Wang
- Mathematics in Medicine Program, The Houston Methodist Research Institute, 6670 Bertner Ave, Houston, Texas 77030, United States
| | - Vittorio Cristini
- Mathematics in Medicine Program, The Houston Methodist Research Institute, 6670 Bertner Ave, Houston, Texas 77030, United States
| | - Vittorio de Franciscis
- Istituto di Endocrinologia ed Oncologia Sperimentale, CNR, 80131 Naples, Italy.,National Research Council (CNR), Institute of Genetic and Biomedical Research (IRGB)-UOS Milan via Rita Levi Montalcini, 20090 Pieve Emanuele (MI), Italy.,Harvard Medical School Initiative for RNA Medicine, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Shuxing Zhang
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - 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, Texas 77030, United States
| | - Rahul Mitra
- Department of Gynecologic Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Cristian Rodriguez-Aguayo
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States.,Center for RNA Interference and Non-Coding RNA, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Anil K Sood
- Center for RNA Interference and Non-Coding RNA, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States.,Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States.,Department of Gynecologic Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Gabriel Lopez-Berestein
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States.,Center for RNA Interference and Non-Coding RNA, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States.,Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
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5
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Blanco C, Janzen E, Pressman A, Saha R, Chen IA. Molecular Fitness Landscapes from High-Coverage Sequence Profiling. Annu Rev Biophys 2019; 48:1-18. [PMID: 30601678 DOI: 10.1146/annurev-biophys-052118-115333] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The function of fitness (or molecular activity) in the space of all possible sequences is known as the fitness landscape. Evolution is a random walk on the fitness landscape, with a bias toward climbing hills. Mapping the topography of real fitness landscapes is fundamental to understanding evolution, but previous efforts were hampered by the difficulty of obtaining large, quantitative data sets. The accessibility of high-throughput sequencing (HTS) has transformed this study, enabling large-scale enumeration of fitness for many mutants and even complete sequence spaces in some cases. We review the progress of high-throughput studies in mapping molecular fitness landscapes, both in vitro and in vivo, as well as opportunities for future research. Such studies are rapidly growing in number. HTS is expected to have a profound effect on the understanding of real molecular fitness landscapes.
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Affiliation(s)
- Celia Blanco
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA; , , , ,
| | - Evan Janzen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA; , , , , .,Biomolecular Science and Engineering Program, University of California, Santa Barbara, California 93106, USA
| | - Abe Pressman
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA; , , , , .,Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA
| | - Ranajay Saha
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA; , , , ,
| | - Irene A Chen
- Biomolecular Science and Engineering Program, University of California, Santa Barbara, California 93106, USA
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6
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Mai J, Li X, Zhang G, Huang Y, Xu R, Shen Q, Lokesh GL, Thiviyanathan V, Chen L, Liu H, Zu Y, Ma X, Volk DE, Gorenstein DG, Ferrari M, Shen H. DNA Thioaptamer with Homing Specificity to Lymphoma Bone Marrow Involvement. Mol Pharm 2018; 15:1814-1825. [PMID: 29537266 PMCID: PMC6311132 DOI: 10.1021/acs.molpharmaceut.7b01169] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Selective drug accumulation in the malignant tissue is a prerequisite for effective cancer treatment. However, most drug molecules and their formulated particles are blocked en route to the destiny tissue due to the existence of multiple biological and physical barriers including the tumor microvessel endothelium. Since the endothelial cells on the surface of the microvessel wall can be modulated by inflammatory cytokines and chemokines secreted by the tumor or stromal cells, an effective drug delivery approach is to enhance interaction between the drug particles and the unique spectrum of surface proteins on the tumor endothelium. In this study, we performed in vivo screening for thioaptamers that bind to the bone marrow endothelium with specificity in a murine model of lymphoma with bone marrow involvement (BMI). The R1 thioaptamer was isolated based on its high homing potency to bones with BMI, and 40-60% less efficiency in accumulation to healthy bones. In cell culture, R1 binds to human umbilical vein endothelial cells (HUVEC) with a high affinity ( Kd ≈ 3 nM), and the binding affinity can be further enhanced when cells were treated with a mixture of lymphoma cell and bone marrow cell conditioned media. Cellular uptake of R1 is through clathrin-mediated endocytosis. Conjugating R1 on to the surface of liposomal doxorubicin nanoparticles resulted in 2-3-fold increase in drug accumulation in lymphoma BMI. Taking together, we have successfully identified a thioaptamer that preferentially binds to the endothelium of lymphoma BMI. It can serve as an affinity moiety for targeted delivery of drug particles to the disease organ.
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Affiliation(s)
- Junhua Mai
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas 77030, USA
| | - Xin Li
- Institute of Molecular Medicine and the Department of Nanomedicine and Biomedical Engineering, McGovern Medical School, The University of Texas Health Science Center at Houston, 1825 Hermann Pressler, Houston 77030, USA
| | - Guodong Zhang
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas 77030, USA
| | - Yi Huang
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas 77030, USA
| | - Rong Xu
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas 77030, USA
| | - Qi Shen
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas 77030, USA
| | - Ganesh L. Lokesh
- Institute of Molecular Medicine and the Department of Nanomedicine and Biomedical Engineering, McGovern Medical School, The University of Texas Health Science Center at Houston, 1825 Hermann Pressler, Houston 77030, USA
| | - Varatharasa Thiviyanathan
- Institute of Molecular Medicine and the Department of Nanomedicine and Biomedical Engineering, McGovern Medical School, The University of Texas Health Science Center at Houston, 1825 Hermann Pressler, Houston 77030, USA
| | - Lingxiao Chen
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas 77030, USA
- Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Haoran Liu
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas 77030, USA
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Youli Zu
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas 77030, USA
| | - Xiaojing Ma
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York 10065, USA
| | - David E. Volk
- Institute of Molecular Medicine and the Department of Nanomedicine and Biomedical Engineering, McGovern Medical School, The University of Texas Health Science Center at Houston, 1825 Hermann Pressler, Houston 77030, USA
| | - David G. Gorenstein
- Institute of Molecular Medicine and the Department of Nanomedicine and Biomedical Engineering, McGovern Medical School, The University of Texas Health Science Center at Houston, 1825 Hermann Pressler, Houston 77030, USA
| | - Mauro Ferrari
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas 77030, USA
- Department of Medicine, Weill Cornell Medical College, New York, New York 10065, USA
| | - Haifa Shen
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas 77030, USA
- Department of Cell and Developmental Biology, Weill Cornell Medical College, New York, New York 10065, USA
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7
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Abstract
Aptamers and second generation analogs, such as X-Aptamers (XAs), SOMAmers, locked nucleic acids (LNAs), and others are increasingly being used for molecular pathway targeting, biomarker discovery, or disease diagnosis by interacting with protein targets on the surface of cells or in solution. Such targeting is being used for imaging, diagnostic evaluation, interference of protein function, or delivery of therapeutic agents. Selection of aptamers using the original SELEX method is cumbersome and time-consuming, often requiring 10-15 rounds of selection, and provides aptamers with a limited number of functional groups, namely four bases of DNA or RNA, although newer SELEX methods have increased this diversity. In contrast, X-Aptamers provide an unlimited number of functional groups and thus are superior targeting agents. Here, we discuss the X-Aptamer selection process.
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8
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Morita Y, Leslie M, Kameyama H, Volk DE, Tanaka T. Aptamer Therapeutics in Cancer: Current and Future. Cancers (Basel) 2018; 10:cancers10030080. [PMID: 29562664 PMCID: PMC5876655 DOI: 10.3390/cancers10030080] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 03/13/2018] [Accepted: 03/15/2018] [Indexed: 12/14/2022] Open
Abstract
Aptamer-related technologies represent a revolutionary advancement in the capacity to rapidly develop new classes of targeting ligands. Structurally distinct RNA and DNA oligonucleotides, aptamers mimic small, protein-binding molecules and exhibit high binding affinity and selectivity. Although their molecular weight is relatively small—approximately one-tenth that of monoclonal antibodies—their complex tertiary folded structures create sufficient recognition surface area for tight interaction with target molecules. Additionally, unlike antibodies, aptamers can be readily chemically synthesized and modified. In addition, aptamers’ long storage period and low immunogenicity are favorable properties for clinical utility. Due to their flexibility of chemical modification, aptamers are conjugated to other chemical entities including chemotherapeutic agents, siRNA, nanoparticles, and solid phase surfaces for therapeutic and diagnostic applications. However, as relatively small sized oligonucleotides, aptamers present several challenges for successful clinical translation. Their short plasma half-lives due to nuclease degradation and rapid renal excretion necessitate further structural modification of aptamers for clinical application. Since the US Food and Drug Administration (FDA) approval of the first aptamer drug, Macugen® (pegaptanib), which treats wet-age-related macular degeneration, several aptamer therapeutics for oncology have followed and shown promise in pre-clinical models as well as clinical trials. This review discusses the advantages and challenges of aptamers and introduces therapeutic aptamers under investigation and in clinical trials for cancer treatments.
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Affiliation(s)
- Yoshihiro Morita
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, 975 NE 10th, BRC-W, Rm 1415, Oklahoma City, OK 73104, USA.
| | - Macall Leslie
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, 975 NE 10th, BRC-W, Rm 1415, Oklahoma City, OK 73104, USA.
| | - Hiroyasu Kameyama
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, 975 NE 10th, BRC-W, Rm 1415, Oklahoma City, OK 73104, USA.
| | - David E Volk
- McGovern Medical School, Institute of Molecular Medicine, University of Texas Health Science Center at Houston, 1825 Hermann Pressler, Houston, TX 77030, USA.
| | - Takemi Tanaka
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, 975 NE 10th, BRC-W, Rm 1415, Oklahoma City, OK 73104, USA.
- Department of Pathology, College of Medicine, University of Oklahoma Health Sciences Center, 940 SL Young Blvd, Oklahoma City, OK 73104, USA.
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9
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Liu H, Mai J, Shen J, Wolfram J, Li Z, Zhang G, Xu R, Li Y, Mu C, Zu Y, Li X, Lokesh GL, Thiviyanathan V, Volk DE, Gorenstein DG, Ferrari M, Hu Z, Shen H. A Novel DNA Aptamer for Dual Targeting of Polymorphonuclear Myeloid-derived Suppressor Cells and Tumor Cells. Am J Cancer Res 2018; 8:31-44. [PMID: 29290791 PMCID: PMC5743458 DOI: 10.7150/thno.21342] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 09/28/2017] [Indexed: 12/17/2022] Open
Abstract
Aptamers have the potential to be used as targeting ligands for cancer treatment as they form unique spatial structures. Methods: In this study, a DNA aptamer (T1) that accumulates in the tumor microenvironment was identified through in vivo selection and validation in breast cancer models. The use of T1 as a targeting ligand was evaluated by conjugating the aptamer to liposomal doxorubicin. Results: T1 exhibited a high affinity for both tumor cells and polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs). Treatment with T1 targeted doxorubicin liposomes triggered apoptosis of breast cancer cells and PMN-MDSCs. Suppression of PMN-MDSCs, which serve an immunosuppressive function, leads to increased intratumoral infiltration of cytotoxic T cells. Conclusion: The cytotoxic and immunomodulatory effects of T1-liposomes resulted in superior therapeutic efficacy compared to treatment with untargeted liposomes, highlighting the promise of T1 as a targeting ligand in cancer therapy.
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10
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Volk DE, Lokesh GLR. Development of Phosphorothioate DNA and DNA Thioaptamers. Biomedicines 2017; 5:E41. [PMID: 28703779 PMCID: PMC5618299 DOI: 10.3390/biomedicines5030041] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/03/2017] [Accepted: 07/11/2017] [Indexed: 02/07/2023] Open
Abstract
Nucleic acid aptamers are short RNA- or DNA-based affinity reagents typically selected from combinatorial libraries to bind to a specific target such as a protein, a small molecule, whole cells or even animals. Aptamers have utility in the development of diagnostic, imaging and therapeutic applications due to their size, physico-chemical nature and ease of synthesis and modification to suit the application. A variety of oligonucleotide modifications have been used to enhance the stability of aptamers from nuclease degradation in vivo. The non-bridging oxygen atoms of the phosphodiester backbones of RNA and DNA aptamers can be substituted with one or two sulfur atoms, resulting in thioaptamers with phosphorothioate or phosphorodithioate linkages, respectively. Such thioaptamers are known to have increased binding affinity towards their target, as well as enhanced resistance to nuclease degradation. In this review, we discuss the development of phosphorothioate chemistry and thioaptamers, with a brief review of selection methods.
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Affiliation(s)
- David E Volk
- McGovern Medical School, Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center, Houston, TX 77030, USA.
| | - Ganesh L R Lokesh
- McGovern Medical School, Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center, Houston, TX 77030, USA.
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11
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Lou X, Egli M, Yang X. Determining Functional Aptamer-Protein Interaction by Biolayer Interferometry. ACTA ACUST UNITED AC 2016; 67:7.25.1-7.25.15. [PMID: 27911494 DOI: 10.1002/cpnc.18] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Short single-stranded nucleic acids called aptamers are widely being explored as recognition molecules of high affinity and specificity for binding a wide range of target molecules, particularly protein targets. In biolayer interferometry (BLI), a simple Dip-and-Read approach in which the aptamer-coated biosensors are dipped into microplate wells is used to study the interactions between an aptamer and its target protein. Here we describe the protocol for the analysis of the interaction between a well-characterized anti-thrombin RNA aptamer with thrombin (Basic Protocol). We also report on the protocol for the affinity screening of a panel of anti-thrombin RNA aptamers with a single phosphorodithioate (PS2) modification, whereby the position of the modification along the RNA backbone is varied systematically (Support Protocol). The PS2 modification uses two sulfur atoms to replace two non-bridging oxygen atoms at an internucleotide phosphodiester backbone linkage. The PS2-modified RNAs are nuclease resistant and several in vitro and in vivo assays have demonstrated their biological activity. For example, combining the PS2 with the 2'-OMe modification affords increased loading of modified small interfering RNA (siRNA) duplexes into the RNA-induced silencing complex (RISC) as well as enhanced gene-silencing antitumor activity. © 2016 by John Wiley & Sons, Inc.
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Affiliation(s)
- Xinhui Lou
- Department of Chemistry, Capital Normal University, Beijing, China
| | - Martin Egli
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee
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12
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Abeydeera ND, Egli M, Cox N, Mercier K, Conde JN, Pallan PS, Mizurini DM, Sierant M, Hibti FE, Hassell T, Wang T, Liu FW, Liu HM, Martinez C, Sood AK, Lybrand TP, Frydman C, Monteiro RQ, Gomer RH, Nawrot B, Yang X. Evoking picomolar binding in RNA by a single phosphorodithioate linkage. Nucleic Acids Res 2016; 44:8052-64. [PMID: 27566147 PMCID: PMC5041495 DOI: 10.1093/nar/gkw725] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/02/2016] [Accepted: 08/06/2016] [Indexed: 11/12/2022] Open
Abstract
RNA aptamers are synthetic oligonucleotide-based affinity molecules that utilize unique three-dimensional structures for their affinity and specificity to a target such as a protein. They hold the promise of numerous advantages over biologically produced antibodies; however, the binding affinity and specificity of RNA aptamers are often insufficient for successful implementation in diagnostic assays or as therapeutic agents. Strong binding affinity is important to improve the downstream applications. We report here the use of the phosphorodithioate (PS2) substitution on a single nucleotide of RNA aptamers to dramatically improve target binding affinity by ∼1000-fold (from nanomolar to picomolar). An X-ray co-crystal structure of the α-thrombin:PS2-aptamer complex reveals a localized induced-fit rearrangement of the PS2-containing nucleotide which leads to enhanced target interaction. High-level quantum mechanical calculations for model systems that mimic the PS2 moiety and phenylalanine demonstrate that an edge-on interaction between sulfur and the aromatic ring is quite favorable, and also confirm that the sulfur analogs are much more polarizable than the corresponding phosphates. This favorable interaction involving the sulfur atom is likely even more significant in the full aptamer-protein complexes than in the model systems.
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Affiliation(s)
| | - Martin Egli
- Department of Biochemistry, Vanderbilt University, School of Medicine, Nashville, TN 37232, USA
| | - Nehemiah Cox
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Karen Mercier
- Biointeractions Division, Horiba Scientific, Avenue de la Vauve - Passage JobinYvon CS 45002 Palaiseau, France
| | - Jonas Nascimento Conde
- Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941, Brazil
| | - Pradeep S Pallan
- Department of Biochemistry, Vanderbilt University, School of Medicine, Nashville, TN 37232, USA
| | - Daniella M Mizurini
- Instituto de Bioquimica Médica Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941, Brazil
| | - Malgorzata Sierant
- Department of Bioorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90-363 Lodz, Sienkiewicza 112, Poland
| | - Fatima-Ezzahra Hibti
- Biointeractions Division, Horiba Scientific, Avenue de la Vauve - Passage JobinYvon CS 45002 Palaiseau, France
| | - Tom Hassell
- MilliporeSigma, 9186 Six Pines, The Woodlands, TX 77380, USA
| | - Tianzhi Wang
- The Sealy Center for Structural Biology & Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Feng-Wu Liu
- School of Pharmaceutical Sciences, Zhengzhou University, Science Avenue 100, Zhengzhou 450001, Henan, China
| | - Hong-Min Liu
- School of Pharmaceutical Sciences, Zhengzhou University, Science Avenue 100, Zhengzhou 450001, Henan, China
| | - Carlos Martinez
- MilliporeSigma, 9186 Six Pines, The Woodlands, TX 77380, USA
| | - Anil K Sood
- Departments of Gynecologic Oncology and Cancer Biology, and Center for RNAi and Non-coding RNA, The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
| | - Terry P Lybrand
- Departments of Chemistry and Pharmacology, and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Chiraz Frydman
- Biointeractions Division, Horiba Scientific, Avenue de la Vauve - Passage JobinYvon CS 45002 Palaiseau, France
| | - Robson Q Monteiro
- Instituto de Bioquimica Médica Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941, Brazil
| | - Richard H Gomer
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Barbara Nawrot
- Department of Bioorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90-363 Lodz, Sienkiewicza 112, Poland
| | - Xianbin Yang
- AM Biotechnologies, LLC, 12521 Gulf Freeway, Houston, TX 77034, USA
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Nguyen D, Zandarashvili L, White MA, Iwahara J. Stereospecific Effects of Oxygen-to-Sulfur Substitution in DNA Phosphate on Ion Pair Dynamics and Protein-DNA Affinity. Chembiochem 2016; 17:1636-42. [PMID: 27271797 DOI: 10.1002/cbic.201600265] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Indexed: 02/05/2023]
Abstract
Oxygen-to-sulfur substitutions in DNA phosphate often enhance affinity for DNA-binding proteins. Our previous studies have suggested that this effect of sulfur substitution of both OP1 and OP2 atoms is due to an entropic gain associated with enhanced ion pair dynamics. In this work, we studied stereospecific effects of single sulfur substitution of either the OP1 or OP2 atom in DNA phosphate at the Lys57 interaction site of the Antennapedia homeodomain-DNA complex. Using crystallography, we obtained structural information on the RP and SP diastereomers of the phosphoromonothioate and their interaction with Lys57. Using fluorescence-based assays, we found significant affinity enhancement upon sulfur substitution of the OP2 atom. Using NMR spectroscopy, we found significant mobilization of the Lys57 side-chain NH3 (+) group upon sulfur substitution of the OP2 atom. These data provide further mechanistic insights into the affinity enhancement by oxygen-to-sulfur substitution in DNA phosphate.
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Affiliation(s)
- Dan Nguyen
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, 301 University Boulevard, Medical Research Building 5.104C, Galveston, TX, 77555-1068, USA
| | - Levani Zandarashvili
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, 301 University Boulevard, Medical Research Building 5.104C, Galveston, TX, 77555-1068, USA
| | - Mark A White
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, 301 University Boulevard, Medical Research Building 5.104C, Galveston, TX, 77555-1068, USA
| | - Junji Iwahara
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, 301 University Boulevard, Medical Research Building 5.104C, Galveston, TX, 77555-1068, USA.
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Yang X, Sierant M, Janicka M, Peczek L, Martinez C, Hassell T, Li N, Li X, Wang T, Nawrot B. Gene silencing activity of siRNA molecules containing phosphorodithioate substitutions. ACS Chem Biol 2012; 7:1214-20. [PMID: 22512638 DOI: 10.1021/cb300078e] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Chemically synthesized small interfering RNAs (siRNAs) have been widely used to identify gene function and hold great potential in providing a new class of therapeutics. Chemical modifications are desired for therapeutic applications to improve siRNA efficacy. Appropriately protected ribonucleoside-3'-yl S-[β-(benzoylmercapto)ethyl]pyrrolidino-thiophosphoramidite monomers were prepared for the synthesis of siRNA containing phosphorodithioate (PS2) substitutions in which the two non-bridging oxygen atoms are replaced by sulfur atoms. A series of siRNAs containing PS2 substitutions have been strategically designed, synthesized, and evaluated for their gene silencing activities. These PS2-siRNA duplexes exhibit an A-form helical structure similar to unmodified siRNA. The effect of PS2 substitutions on gene silencing activity is position-dependent, with certain PS2-siRNAs showing activity significantly higher than that of unmodified siRNA. The relative gene silencing activities of siRNAs containing either PS2 or phosphoromonothioate (PS) linkages at identical positions are variable and depend on the sites of modification. 5'-Phosphorylation of PS2-siRNAs has little or no effect on gene silencing activity. Incorporation of PS2 substitutions into siRNA duplexes increases their serum stability. These results offer preliminary evidence of the potential value of PS2-modified siRNAs.
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Affiliation(s)
- Xianbin Yang
- AM Biotechnologies LLC, 12521 Gulf Freeway, Houston, Texas 77034, United
States
| | - Malgorzata Sierant
- Department of Bioorganic
Chemistry,
Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Lodz, Poland
| | - Magdalena Janicka
- Department of Bioorganic
Chemistry,
Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Lodz, Poland
| | - Lukasz Peczek
- Department of Bioorganic
Chemistry,
Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Lodz, Poland
| | - Carlos Martinez
- Sigma Life Science, 9186 Six Pines, The Woodlands, Texas 77380, United States
| | - Tom Hassell
- Sigma Life Science, 9186 Six Pines, The Woodlands, Texas 77380, United States
| | - Na Li
- AM Biotechnologies LLC, 12521 Gulf Freeway, Houston, Texas 77034, United
States
| | - Xin Li
- AM Biotechnologies LLC, 12521 Gulf Freeway, Houston, Texas 77034, United
States
| | - Tianzhi Wang
- The Sealy Center for Structural Biology & Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Barbara Nawrot
- Department of Bioorganic
Chemistry,
Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Lodz, Poland
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15
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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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Hecht AH, Sommer GJ, Durland RH, Yang X, Singh AK, Hatch AV. Aptamers as affinity reagents in an integrated electrophoretic lab-on-a-chip platform. Anal Chem 2010; 82:8813-20. [PMID: 20945866 DOI: 10.1021/ac101106m] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Nucleic acid based affinity reagents (e.g., aptamers) offer several possible advantages over antibodies as specific recognition elements in biochemical assays. Besides offering improved cost and stability, aptamers are ideal for rapid electrophoretic analysis due to their low molecular weight and high negative charge. While aptamers have proven well-suited for affinity-shift electrophoretic analysis, demonstrating a fully integrated aptamer-based assay platform represents an important achievement toward low-cost point-of-care analysis, particularly for remote or resource poor settings where cost and ambient stability of reagents is a key consideration. Here we perform and evaluate the suitability of aptamer-based affinity assays for two clinically relevant target analytes (IgE using a known aptamer and NF-κB using a thio-modified aptamer) in an integrated electrophoretic gel-shift platform. Key steps of (i) mixing sample with aptamer, (ii) buffer exchange, and (iii) preconcentration of sample were successfully integrated on-chip upstream of a fluorescence-based gel-shift analysis step. This approach, utilizing a size-exclusion membrane optimized here for aptamer retention and preconcentration with sample, enables automated sample-to-answer for trace analytes in 10 min or less. We addressed notable nonspecific interference from serum proteins by adding similar nucleic acid competitors to suppress such interactions with the aptamer. Nanomolar sensitivities were demonstrated and integrated preconcentration of sample provides an important means of further improving detection sensitivities. Aptamers proved superior in many respects to antibody reagents, particularly with regard to speed and resolution of gel-shifts associated with specific binding to target.
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Affiliation(s)
- Ariel H Hecht
- Sandia National Laboratories, Livermore, California 94551, United States, University of Michigan, Ann Arbor, Michigan 48109, United States, and AM Biotechnologies, LLC, Houston, Texas 77034, United States
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17
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Bowick GC, Fennewald SM, Zhang L, Yang X, Aronson JF, Shope RE, Luxon BA, Gorenstein DG, Herzog NK. Attenuated and lethal variants of Pichindé virus induce differential patterns of NF-kappaB activation suggesting a potential target for novel therapeutics. Viral Immunol 2010; 22:457-62. [PMID: 19951183 DOI: 10.1089/vim.2009.0034] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Lassa virus pathogenesis is believed to involve dysregulation of cytokines. We have previously shown nuclear factor-kappaB (NF-kappaB) inhibition using a BSL-2 model for Lassa fever. Here we further define the potential mechanism for NF-kappaB inhibition as involving increased levels of repressive p50/p50 homodimers, and suggest a novel therapeutic strategy that acts via modulation of host signaling.
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Affiliation(s)
- Gavin C Bowick
- Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas 77555-0609, USA
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18
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19
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Wochner A, Menger M, Rimmele M. Characterisation of aptamers for therapeutic studies. Expert Opin Drug Discov 2007; 2:1205-24. [DOI: 10.1517/17460441.2.9.1205] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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20
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Modelling the interaction of several bisphosphonates with hydroxyapatite using the generalised AMBER force field. J Mol Struct 2006. [DOI: 10.1016/j.molstruc.2006.04.032] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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21
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Yang X, Bassett SE, Li X, Luxon BA, Herzog NK, Shope RE, Aronson J, Prow TW, Leary JF, Kirby R, Ellington AD, Gorenstein DG. Construction and selection of bead-bound combinatorial oligonucleoside phosphorothioate and phosphorodithioate aptamer libraries designed for rapid PCR-based sequencing. Nucleic Acids Res 2002; 30:e132. [PMID: 12466564 PMCID: PMC137987 DOI: 10.1093/nar/gnf132] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2002] [Revised: 09/23/2002] [Accepted: 10/03/2002] [Indexed: 11/13/2022] Open
Abstract
Chemically synthesized combinatorial libraries of unmodified or modified nucleic acids have not previously been used in methods to rapidly select oligonucleotides binding to target biomolecules such as proteins. Phosphorothioate oligonucleotides (S-ODNs) or phosphorodithioate oligonucleotides (S2-ODNs) with sulfurs replacing one or both of the non-bridging phosphate oxygens bind to proteins more tightly than unmodified oligonucleotides and have the potential to be used as diagnostic reagents and therapeutics. We have applied a split synthesis methodology to create one-bead one-S-ODN and one-bead one-S2-ODN libraries. Binding and selection of specific beads to the transcription factor NF-kappaB p50/p50 protein were demonstrated. Sequencing both the nucleic acid bases and the positions of any 3'-O-thioate/dithioate linkages was carried out by using a novel PCR-based identification tag of the selected beads. This approach allows us to rapidly and conveniently identify S-ODNs or S2-ODNs that bind to proteins.
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Affiliation(s)
- Xianbin Yang
- Sealy Center for Structural Biology and Department of Human Biological Chemistry and Genetics, 301 University Boulevard, The University of Texas Medical Branch at Galveston, TX 77555-1157, USA
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Yang X, Hodge RP, Luxon BA, Shope R, Gorenstein DG. Separation of synthetic oligonucleotide dithioates from monothiophosphate impurities by anion-exchange chromatography on a mono-q column. Anal Biochem 2002; 306:92-9. [PMID: 12069419 DOI: 10.1006/abio.2001.5694] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A method using a strong anion-exchange liquid-chromatography column, Mono-Q, has been developed for high-resolution analysis and purification of oligonucleotide dithioates, which were synthesized by an automated, solid-phase, phosphorothioamidite chemistry. High-resolution separation of oligonucleotide phosphorodithioates from monothiophosphate impurities was obtained. High-resolution separation was also demonstrated at pH 8. The separation of oligonucleotide dithioates was found to be linearly dependent on the number of sulfurs for the same sequence length. Thiocyanate, SCN-, as eluting anion, can be used to purify oligonucleotides containing a high percentage of phosphorodithioate linkages in lower salt concentrations and provides better separation than chloride as eluting anion.
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Affiliation(s)
- Xianbin Yang
- Sealy Center for Structural Biology and Department of Human Biological Chemistry & Genetics, University of Texas Medical Branch at Galveston, TX 77555, USA
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