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Moreira L, Guimarães NM, Santos RS, Loureiro JA, Pereira MDC, Azevedo NF. Oligonucleotide probes for imaging and diagnosis of bacterial infections. Crit Rev Biotechnol 2024:1-20. [PMID: 38830823 DOI: 10.1080/07388551.2024.2344574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 06/17/2023] [Indexed: 06/05/2024]
Abstract
The rise of infectious diseases as a public health concern has necessitated the development of rapid and precise diagnostic methods. Imaging techniques like nuclear and optical imaging provide the ability to diagnose infectious diseases within the body, eliminating delays caused by sampling and pre-enrichments of clinical samples and offering spatial information that can aid in a more informed diagnosis. Traditional molecular probes are typically created to image infected tissue without accurately identifying the pathogen. In contrast, oligonucleotides can be tailored to target specific RNA sequences, allowing for the identification of pathogens, and even generating antibiotic susceptibility profiles by focusing on drug resistance genes. Despite the benefits that nucleic acid mimics (NAMs) have provided in terms of stabilizing oligonucleotides, the inadequate delivery of these relatively large molecules into the cytoplasm of bacteria remains a challenge for widespread use of this technology. This review summarizes the key advancements in the field of oligonucleotide probes for in vivo imaging, highlighting the most promising delivery systems described in the literature for developing optical imaging through in vivo hybridization.
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Affiliation(s)
- Luís Moreira
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - Nuno Miguel Guimarães
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - Rita Sobral Santos
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - Joana Angélica Loureiro
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - Maria do Carmo Pereira
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - Nuno Filipe Azevedo
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
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2
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Synthesis and in vivo evaluation of 18F-cPNA and Dendrimer-PNA conjugate for amplification pretargeting. J Radioanal Nucl Chem 2022. [DOI: 10.1007/s10967-022-08289-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Herkt M, Thum T. Pharmacokinetics and Proceedings in Clinical Application of Nucleic Acid Therapeutics. Mol Ther 2021; 29:521-539. [PMID: 33188937 PMCID: PMC7854291 DOI: 10.1016/j.ymthe.2020.11.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 10/27/2020] [Accepted: 11/03/2020] [Indexed: 02/07/2023] Open
Abstract
Oligonucleotide therapeutics are a novel promising class of drugs designed to specifically target either coding or non-coding RNA molecules to revolutionize treatment of various diseases. During preclinical development, investigations of the pharmacokinetic characteristics of these oligonucleotide-based drug candidates are essential. Oligonucleotides possess a long history of chemical modifications to enhance their stability and binding affinity, as well as reducing toxicity. Phosphorothioate backbone modifications of oligonucleotides were a hallmark of this development process that greatly enhanced plasma stability and protein binding of these agents. Modifications such as 2'-O-methylation further improved stability, while other modifications of the ribose, such as locked nucleic acid (LNA) modification, significantly increased binding affinity, potency, and tissue half-life. These attributes render oligonucleotide therapeutics able to regulate protein expression in both directions depending on the target RNA. Thus, a growing interest has emerged using these oligonucleotides in the treatment of neurodegenerative and cardiac disorders as well as cancer, since the deregulation of certain coding and non-coding RNAs plays a key role in the development of these diseases. Cutting edge research is being performed in the field of non-coding RNAs, identifying potential therapeutic targets, and developing novel oligonucleotide-based agents that outperform classical drugs. Some of these agents are either in clinical trials showing promising results or are already US Food and Drug Administration (FDA) approved, with more oligonucleotides being developed for therapeutic purposes. This is the advent of mechanism-based next-generation therapeutics for a wide range of diseases.
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Affiliation(s)
- Markus Herkt
- Institute of Molecular and Translational Therapeutic Strategies (IMTTS), Hannover Medical School (MHH), Hannover, Germany.
| | - Thomas Thum
- Institute of Molecular and Translational Therapeutic Strategies (IMTTS), Hannover Medical School (MHH), Hannover, Germany; REBIRTH Center for Translational Regenerative Medicine, Hannover Medical School (MHH), Hannover, Germany; Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany.
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4
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Mustonen EK, Palomäki T, Pasanen M. Oligonucleotide-based pharmaceuticals: Non-clinical and clinical safety signals and non-clinical testing strategies. Regul Toxicol Pharmacol 2017; 90:328-341. [PMID: 28966105 DOI: 10.1016/j.yrtph.2017.09.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 09/25/2017] [Accepted: 09/27/2017] [Indexed: 12/21/2022]
Abstract
Antisense oligonucleotides, short interfering RNAs (siRNAs) and aptamers are oligonucleotide-based pharmaceuticals with a promising role in targeted therapies. Currently, five oligonucleotide-based pharmaceuticals have achieved marketing authorization in Europe or USA and many more are undergoing clinical testing. However, several safety concerns have been raised in non-clinical and clinical studies. Oligonucleotides share properties with both chemical and biological pharmaceuticals and therefore they pose challenges also from the regulatory point of view. We have analyzed the safety data of oligonucleotides and evaluated the applicability of current non-clinical toxicological guidelines for assessing the safety of oligonucleotide-based pharmaceuticals. Oligonucleotide-based pharmaceuticals display a similar toxicological profile, exerting adverse effects on liver and kidney, evoking hematological alterations, as well as causing immunostimulation and prolonging the coagulation time. It is possible to extrapolate some of these effects from non-clinical studies to humans. However, evaluation strategies for genotoxicity testing of "non-natural" oligonucleotides should be revised. Additionally, the selective use of surrogates and prediction of clinical endpoints for non-clinically observed immunostimulation is complicated by its multiple potential manifestations, demanding improvements in the testing strategies. Utilizing more relevant and mechanistic-based approaches and taking better account of species differences, could possibly improve the prediction of relevant immunological/proinflammatory effects in humans.
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Affiliation(s)
- Enni-Kaisa Mustonen
- University of Eastern Finland, Faculty of Health Sciences, School of Pharmacy, P.O. Box 1627, 70211 Kuopio, Finland
| | | | - Markku Pasanen
- University of Eastern Finland, Faculty of Health Sciences, School of Pharmacy, P.O. Box 1627, 70211 Kuopio, Finland.
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Yamamoto T, Wada F, Harada-Shiba M. Development of Antisense Drugs for Dyslipidemia. J Atheroscler Thromb 2016; 23:1011-25. [PMID: 27466159 PMCID: PMC5090806 DOI: 10.5551/jat.rv16001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Abnormal elevation of low-density lipoprotein (LDL) and triglyceride-rich lipoproteins in plasma as well as dysfunction of anti-atherogenic high-density lipoprotein (HDL) have both been recognized as essential components of the pathogenesis of atherosclerosis and are classified as dyslipidemia. This review describes the arc of development of antisense oligonucleotides for the treatment of dyslipidemia. Chemically-armed antisense candidates can act on various kinds of transcripts, including mRNA and miRNA, via several different endogenous antisense mechanisms, and have exhibited potent systemic anti-dyslipidemic effects. Here, we present specific cutting-edge technologies have recently been brought into antisense strategies, and describe how they have improved the potency of antisense drugs in regard to pharmacokinetics and pharmacodynamics. In addition, we discuss perspectives for the use of armed antisense oligonucleotides as new clinical options for dyslipidemia, in the light of outcomes of recent clinical trials and safety concerns indicated by several clinical and preclinical studies.
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Gijs M, Aerts A, Impens N, Baatout S, Luxen A. Aptamers as radiopharmaceuticals for nuclear imaging and therapy. Nucl Med Biol 2015; 43:253-71. [PMID: 26746572 DOI: 10.1016/j.nucmedbio.2015.09.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 08/24/2015] [Accepted: 09/10/2015] [Indexed: 12/27/2022]
Abstract
Today, radiopharmaceuticals belong to the standard instrumentation of nuclear medicine, both in the context of diagnosis and therapy. The majority of radiopharmaceuticals consist of targeting biomolecules which are designed to interact with a disease-related molecular target. A plethora of targeting biomolecules of radiopharmaceuticals exists, including antibodies, antibody fragments, proteins, peptides and nucleic acids. Nucleic acids have some significant advantages relative to proteinaceous biomolecules in terms of size, production, modifications, possible targets and immunogenicity. In particular, aptamers (non-coding, synthetic, single-stranded DNA or RNA oligonucleotides) are of interest because they can bind a molecular target with high affinity and specificity. At present, few aptamers have been investigated preclinically for imaging and therapeutic applications. In this review, we describe the use of aptamers as targeting biomolecules of radiopharmaceuticals. We also discuss the chemical modifications which are needed to turn aptamers into valuable (radio-)pharmaceuticals, as well as the different radiolabeling strategies that can be used to radiolabel oligonucleotides and, in particular, aptamers.
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Affiliation(s)
- Marlies Gijs
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK·CEN), Mol, Belgium; Cyclotron Research Centre, University of Liège, Liège, Belgium
| | - An Aerts
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK·CEN), Mol, Belgium
| | - Nathalie Impens
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK·CEN), Mol, Belgium
| | - Sarah Baatout
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK·CEN), Mol, Belgium
| | - André Luxen
- Cyclotron Research Centre, University of Liège, Liège, Belgium.
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7
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Hori SI, Yamamoto T, Waki R, Wada S, Wada F, Noda M, Obika S. Ca2+ enrichment in culture medium potentiates effect of oligonucleotides. Nucleic Acids Res 2015; 43:e128. [PMID: 26101258 PMCID: PMC4627064 DOI: 10.1093/nar/gkv626] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 06/04/2015] [Indexed: 01/28/2023] Open
Abstract
Antisense and RNAi-related oligonucleotides have gained attention as laboratory tools and therapeutic agents based on their ability to manipulate biological events in vitro and in vivo. We show that Ca2+ enrichment of medium (CEM) potentiates the in vitro activity of multiple types of oligonucleotides, independent of their net charge and modifications, in various cells. In addition, CEM reflects in vivo silencing activity more consistently than conventional transfection methods. Microscopic analysis reveals that CEM provides a subcellular localization pattern of oligonucleotides resembling that obtained by unassisted transfection, but with quantitative improvement. Highly monodispersed nanoparticles ∼100 nm in size are found in Ca2+-enriched serum-containing medium regardless of the presence or absence of oligonucleotides. Transmission electron microscopy analysis reveals that the 100-nm particles are in fact an ensemble of much smaller nanoparticles (ϕ ∼ 15 nm). The presence of these nanoparticles is critical for the efficient uptake of various oligonucleotides. In contrast, CEM is ineffective for plasmids, which are readily transfected via the conventional calcium phosphate method. Collectively, CEM enables a more accurate prediction of the systemic activity of therapeutic oligonucleotides, while enhancing the broad usability of oligonucleotides in the laboratory.
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Affiliation(s)
- Shin-Ichiro Hori
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Tsuyoshi Yamamoto
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Reiko Waki
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Shunsuke Wada
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Fumito Wada
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Mio Noda
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Satoshi Obika
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka, 565-0871, Japan
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8
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Velikyan I. Continued rapid growth in68Ga applications: update 2013 to June 2014. J Labelled Comp Radiopharm 2015; 58:99-121. [DOI: 10.1002/jlcr.3250] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 11/13/2014] [Accepted: 11/21/2014] [Indexed: 12/21/2022]
Affiliation(s)
- Irina Velikyan
- Preclinical PET Platform, Department of Medicinal Chemistry; Uppsala University; SE-75183 Uppsala Sweden
- Department of Radiology, Oncology and Radiation Science; Uppsala University; SE-75285 Uppsala Sweden
- PET-Centre, Centre for Medical Imaging; Uppsala University Hospital; SE-75185 Uppsala Sweden
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Velikyan I. Prospective of ⁶⁸Ga-radiopharmaceutical development. Theranostics 2013; 4:47-80. [PMID: 24396515 PMCID: PMC3881227 DOI: 10.7150/thno.7447] [Citation(s) in RCA: 235] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 10/01/2013] [Indexed: 01/29/2023] Open
Abstract
Positron Emission Tomography (PET) experienced accelerated development and has become an established method for medical research and clinical routine diagnostics on patient individualized basis. Development and availability of new radiopharmaceuticals specific for particular diseases is one of the driving forces of the expansion of clinical PET. The future development of the ⁶⁸Ga-radiopharmaceuticals must be put in the context of several aspects such as role of PET in nuclear medicine, unmet medical needs, identification of new biomarkers, targets and corresponding ligands, production and availability of ⁶⁸Ga, automation of the radiopharmaceutical production, progress of positron emission tomography technologies and image analysis methodologies for improved quantitation accuracy, PET radiopharmaceutical regulations as well as advances in radiopharmaceutical chemistry. The review presents the prospects of the ⁶⁸Ga-based radiopharmaceutical development on the basis of the current status of these aspects as well as wide range and variety of imaging agents.
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Affiliation(s)
- Irina Velikyan
- 1. Preclinical PET Platform, Department of Medicinal Chemistry, Uppsala University, SE-75183 Uppsala, Sweden
- 2. PET-Centre, Centre for Medical Imaging, Uppsala University Hospital, SE-75185, Uppsala, Sweden
- 3. Department of Radiology, Oncology, and Radiation Science, Uppsala University, SE-75285 Uppsala, Sweden
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10
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Abstract
Development of new radiopharmaceuticals and their availability are crucial factors influencing the expansion of clinical nuclear medicine. The number of new (68)Ga-based imaging agents for positron emission tomography (PET) is increasing greatly. (68)Ga has been used for labeling of a broad range of molecules (small organic molecules, peptides, proteins, and oligonucleotides) as well as particles, thus demonstrating its potential to become a PET analog of the legendary generator-produced gamma-emitting (99m)Tc but with added value of higher sensitivity and resolution as well as quantitation and dynamic scanning. Further, the availability of technology for GMP-compliant automated tracer production can facilitate the introduction of new radiopharmaceuticals and enable standardized, harmonized multicenter studies to be conducted for regulatory approval. This chapter presents some examples of tracers for targeted, pretargeted, and nontargeted imaging with emphasis on the potential of (68)Ga to facilitate clinically practical PET development and to promote the PET technique worldwide for earlier and better diagnostics, and personalized medicine with the ultimate objective of improved therapeutic outcome.
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Affiliation(s)
- Irina Velikyan
- Department of Radiology, Uppsala University, Uppsala, Sweden.
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11
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Abstract
Drug development is a complex process, requiring scientific and regulatory input at almost all stages from multiple groups of expertise. Small molecule development issues are covered in other parts of this volume. This chapter is devoted to discussing the large molecules, or biologics, and the particular nuances involved in developing these molecules as medicines. Our definition of biologic, for the purposes of this chapter, differs from that described by the regulatory bodies. Where regulators state that a biologic is a molecule produced by a living organism, be it a mammalian, insect, yeast or bacteria cell, or whole animal, we prefer to include molecules such as oligonucleotides and peptides here, which are usually chemically synthesized. So our definition is that of a molecule whose composition mostly entails naturally occurring amino acids, sugars or nucleotide bases. There are modifications made chemically to oligonucleotides and peptides to improve their drug-like properties, but for this volume, we class them as biologics. The aim of this chapter is to describe some of the differences, complexities and paradoxically, simplifications in the pharmacokinetics and ADME sciences during drug development of biologics when compared to the more familiar small molecule drug development process. The impact of the particular pharmacokinetics and ADME sciences of biologics on toxicological and pharmacological end points will be discussed.
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Affiliation(s)
- Kevin Brady
- Bicycle Therapeutics Ltd., Cambridge, United Kingdom
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12
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Abstract
Numerous chemically modified oligonucleotides have been developed so far and show their own unique chemical properties and pharmacodynamic/pharmacokinetic characteristics. Among all non-natural nucleotides, to the best of our knowledge, only five chemistries are currently being tested in clinical trials: phosphorothioate, 2´-O-methyl RNA, 2´-O-methoxyethyl RNA, 2´,4´-bridged nucleic acid/locked nucleic acid and the phosphorodiamidate morpholino oligomer. Since phosphorothioate modification can improve the pharmacokinetics of oligonucleotides, this modification is currently used in combination with all other modifications except phosphorodiamidate morpholino oligomer. For the treatment of metabolic, cardiovascular, cancer and other systemic diseases, the phosphorothioate class of drugs is obviously helpful, while superior efficacies can be observed in phosphorodiamidate morpholino oligomer compared to other classes of oligonucleotides for the treatment of Duchenne muscular dystrophy. Which properties of antisense molecules are actually essential for clinical applications? In this article, we provide an overview of the medicinal chemistry of existing non-natural antisense molecules, as well as their clinical applications, to discuss which properties of antisense oligonuculeotides affect therapeutic potency.
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Abstract
Oligonucleotides radiolabeled with isotopes emitting γ-rays (for SPECT imaging) or positrons (for PET imaging) can be useful for targeting messenger RNA (mRNA) thereby serving as non-invasive imaging tools for detection of gene expression in vivo (antisense imaging). Radiolabeled oligonucleotides may also be used for monitoring their in vivo fate, thereby helping us better understand the barriers to its delivery for antisense targeting. These developments have led to a new area of molecular imaging and targeting, utilizing radiolabeled antisense oligonucleotides. However, the success of antisense imaging relies heavily on overcoming the barriers for its targeted delivery in vivo. Furthermore, the low ability of the radiolabeled antisense oligonucleotide to subsequently internalize into the cell and hybridize with its target mRNA poses additional challenges in realizing its potentials. This review covers the advances in the antisense imaging probe development for PET and SPECT, with an emphasis on radiolabeling strategies, stability, delivery and in vivo targeting.
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Affiliation(s)
- Arun K Iyer
- Center for Molecular and Functional Imaging, Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA 94143
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Wadas TJ, Wong EH, Weisman GR, Anderson CJ. Coordinating radiometals of copper, gallium, indium, yttrium, and zirconium for PET and SPECT imaging of disease. Chem Rev 2010; 110:2858-902. [PMID: 20415480 PMCID: PMC2874951 DOI: 10.1021/cr900325h] [Citation(s) in RCA: 681] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Thaddeus J Wadas
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd., Campus Box 8225 St. Louis, Missouri 63110, USA.
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Abstract
BACKGROUND The use of oligonucleotides as therapeutic agents has elicited a great deal of interest. Basic understanding and evaluation of the pharmacokinetic properties of oligonucleotides is foundational to their appropriate design and application. OBJECTIVE To review the primary pharmacokinetic properties that drive successful use and delivery of oligonucleotides. METHODS The primary data set available in the published literature for summarizing the pharmacokinetic properties of oligonucleotides exists for single strand phosphorothioate antisense oligonucleotides and their chimeric chemical modifications (second generation). Where possible, data from other classes of compounds are contrasted with this base class. RESULTS/CONCLUSION Although there are several different classes of oligonucleotides being developed as therapeutic agents, their pharmacokinetic properties by class are primarily a function of their backbone chemistry and the resulting chemical relationship to biological stability and plasma protein binding properties.
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Affiliation(s)
- Richard S Geary
- Isis Pharmaceuticals, Inc., 1896 Rutherford Rd, Carlsbad, CA 92008, USA.
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16
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Lendvai G, Monazzam A, Velikyan I, Eriksson B, Josephsson R, Långström B, Bergström M, Estrada S. Non-hybridization saturable mechanisms play a role in the uptake of (68)Ga-Labeled LNA-DNA mixmer antisense oligonucleotides in rats. Oligonucleotides 2009; 19:223-32. [PMID: 19732020 DOI: 10.1089/oli.2009.0192] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Oligonucleotides (ODN) are key molecules for the aim of preventing translation of a gene product or monitoring gene expression in tissues. However, multiple methodological and biological hurdles need to be solved before in vivo application in humans will be possible. For positron emission tomography (PET) investigations, a 20-mer DNA-locked nucleic acid (LNA) mixmer ODN specific for rat chromogranin-A mRNA was labeled with (68)Ga and its uptake was examined in vivo in rats with and without blocking of scavenger receptors by polyribonucleotides. In addition, uptake studies of (68)Ga-LNA were performed with respect to time and concentration in human and rat cell lines. The human cell lines did not express the target mRNA. Both polyinosinic acid (poly-I) and polyadenylic acid (poly-A) reduced the uptake in rat tissues and in human cell lines. Poly-I was found to be more effective in the liver whereas poly-A was more effective in the kidney. In addition, the blockade by poly-I was statistically significant in the pancreas, adrenal gland, bone marrow, intestine, testis, urinary bladder, muscle, parotid gland, and heart, whereas poly-A also caused significant reduction in pancreas, adrenal gland, and bone marrow but not as much as in kidney. Cell culture study showed a 2-phase dose-dependent uptake characteristic with a saturable and a passive diffusion-like phase; however, these 2 phases were not so well expressed in the rat cell line. The results suggest that scavenger receptors or other saturable processes unrelated to hybridization may be involved in the tissue uptake of (68)Ga-LNA and in the clearance of antisense ODN through the liver, kidney, spleen, and bone marrow. The fact that these processes may be sequence-dependent suggests that proof of in vivo hybridization through imaging may not be obtained by only comparing sense and antisense sequences and proving dose-dependency.
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Affiliation(s)
- Gabor Lendvai
- Uppsala Imanet, GEMS PET Systems, GE Healthcare, Uppsala S-751 09, Sweden
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Hernandez FJ, Kalra N, Wengel J, Vester B. Aptamers as a model for functional evaluation of LNA and 2'-amino LNA. Bioorg Med Chem Lett 2009; 19:6585-7. [PMID: 19864131 DOI: 10.1016/j.bmcl.2009.10.039] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 10/06/2009] [Accepted: 10/07/2009] [Indexed: 10/20/2022]
Abstract
The affinity change upon incorporation of LNA and 2'-amino-LNA monomers into an avidin binding DNA aptamer is described. The kinetic profile of selected modified-aptamer was obtained by surface plasmon resonance experiments and compared with the profile of the parent unmodified DNA aptamer. We report significant improvement of avidin binding affinity by the incorporation of single LNA modifications into the aptamer, and successful incorporation of 2'-amino LNA as a novel monomer in aptamers with potential function as carrier unit for additional molecular entities.
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Affiliation(s)
- Frank J Hernandez
- Biochemistry and Molecular Biology Department, Nucleic Acid Center, University of Southern Denmark, Campusvej 55, Odense M 5230, Denmark
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Abstract
Antisense oligonucleotides as a therapeutic platform have been slow to progress since the approval of the first antisense drug in 1998. Recently, there have been several examples of convincing antisense interventions in animal models and promising clinical trial data. This review considers the factors determining the success of antisense oligonucleotides as therapeutic agents. In order to produce target knockdown after systemic delivery, antisense oligonucleotides must avoid nuclease degradation, reticuloendothelial-system uptake and rapid renal excretion, and extravasate to the target cell type outside the vasculature. They then must enter the target cell, and escape the endosome-lysosome pathway so as to be free to interact with the target mRNA. We consider the significance of these limiting factors based on the literature and our own experience using systemic administration of antisense oligonucleotides.
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Abstract
MR imaging has had a major impact on understanding the dynamic neuropathologic findings of multiple sclerosis (MS), early diagnosis of the disease, and clinical trial conduct. The next 10 years can be expected to see further advances with a greater emphasis on large multicenter studies, new techniques and hardware allowing greater imaging sensitivity and resolution, and the exploitation of positron emission tomography molecular imaging for MS. The impact should be felt with a new emphasis on gray matter disease and processes of repair. With new ways of monitoring the disease, new treatment targets should become practical, helping to translate advances in the understanding of immunology and regenerative medicine into novel therapies.
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Affiliation(s)
- Paul M Matthews
- Glaxo Smith Kline Clinical Imaging Centre, Hammersmith Hospital, London, UK.
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