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Raguraman P, Wang T, Ma L, Jørgensen PT, Wengel J, Veedu RN. Alpha-l-Locked Nucleic Acid-Modified Antisense Oligonucleotides Induce Efficient Splice Modulation In Vitro. Int J Mol Sci 2020; 21:ijms21072434. [PMID: 32244535 PMCID: PMC7177859 DOI: 10.3390/ijms21072434] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/27/2020] [Accepted: 03/29/2020] [Indexed: 01/04/2023] Open
Abstract
Alpha-l-Locked nucleic acid (α-l-LNA) is a stereoisomeric analogue of locked nucleic acid (LNA), which possesses excellent biophysical properties and also exhibits high target binding affinity to complementary oligonucleotide sequences and resistance to nuclease degradations. Therefore, α-l-LNA nucleotides could be utilised to develop stable antisense oligonucleotides (AO), which can be truncated without compromising the integrity and efficacy of the AO. In this study, we explored the potential of α-l-LNA nucleotides-modified antisense oligonucleotides to modulate splicing by inducing Dmd exon-23 skipping in mdx mouse myoblasts in vitro. For this purpose, we have synthesised and systematically evaluated the efficacy of α-l-LNA-modified 2'-O-methyl phosphorothioate (2'-OMePS) AOs of three different sizes including 20mer, 18mer and 16mer AOs in parallel to fully-modified 2'-OMePS control AOs. Our results demonstrated that the 18mer and 16mer truncated AO variants showed slightly better exon-skipping efficacy when compared with the fully-23 modified 2'-OMePS control AOs, in addition to showing low cytotoxicity. As there was no previous report on using α-l-LNA-modified AOs in splice modulation, we firmly believe that this initial study could be beneficial to further explore and expand the scope of α-l-LNA-modified AO therapeutic molecules.
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Affiliation(s)
- Prithi Raguraman
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth 6150 Australia; (P.R.); (T.W.)
- Perron Institute for Neurological and translational Science, Perth 6005, Australia
| | - Tao Wang
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth 6150 Australia; (P.R.); (T.W.)
- Perron Institute for Neurological and translational Science, Perth 6005, Australia
| | - Lixia Ma
- School of Statistics, Henan University of Economics and Law, Zhengzhou 450001, China;
| | - Per Trolle Jørgensen
- Nucleic Acid Center, Department of Physics and Chemistry and Pharmacy, University of Southern Denmark, M 5230 Odense, Denmark; (P.T.J.); (J.W.)
| | - Jesper Wengel
- Nucleic Acid Center, Department of Physics and Chemistry and Pharmacy, University of Southern Denmark, M 5230 Odense, Denmark; (P.T.J.); (J.W.)
| | - Rakesh N. Veedu
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth 6150 Australia; (P.R.); (T.W.)
- Perron Institute for Neurological and translational Science, Perth 6005, Australia
- Nucleic Acid Center, Department of Physics and Chemistry and Pharmacy, University of Southern Denmark, M 5230 Odense, Denmark; (P.T.J.); (J.W.)
- Correspondence:
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Mori K, Kodama T, Obika S. Synthesis and hybridization property of a boat-shaped pyranosyl nucleic acid containing an exocyclic methylene group in the sugar moiety. Bioorg Med Chem 2014; 23:33-7. [PMID: 25496806 DOI: 10.1016/j.bmc.2014.11.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 11/19/2014] [Accepted: 11/20/2014] [Indexed: 12/29/2022]
Abstract
A boat-shaped pyranosyl nucleic acid (BsNA) having an exocyclic methylene group in the sugar moiety was synthesized to investigate the possibility that the axial H3' of original BsNA is the cause of its duplex destabilization. The synthesized BsNA analog was chemically stable against various nucleophiles. From the thermal stability of duplex oligonucleotides including the BsNA analog, it was found that the duplex-forming ability can be sensitive to the size of functional groups at the 3'-position.
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Affiliation(s)
- Kazuto Mori
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tetsuya Kodama
- Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan.
| | - Satoshi Obika
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
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Kumar P, Baral B, Anderson BA, Guenther DC, Østergaard ME, Sharma PK, Hrdlicka PJ. C5-alkynyl-functionalized α-L-LNA: synthesis, thermal denaturation experiments and enzymatic stability. J Org Chem 2014; 79:5062-73. [PMID: 24797769 PMCID: PMC4049248 DOI: 10.1021/jo5006153] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Indexed: 12/23/2022]
Abstract
Major efforts are currently being devoted to improving the binding affinity, target specificity, and enzymatic stability of oligonucleotides used for nucleic acid targeting applications in molecular biology, biotechnology, and medicinal chemistry. One of the most popular strategies toward this end has been to introduce additional modifications to the sugar ring of affinity-inducing conformationally restricted nucleotide building blocks such as locked nucleic acid (LNA). In the preceding article in this issue, we introduced a different strategy toward this end, i.e., C5-functionalization of LNA uridines. In the present article, we extend this strategy to α-L-LNA: i.e., one of the most interesting diastereomers of LNA. α-L-LNA uridine monomers that are conjugated to small C5-alkynyl substituents induce significant improvements in target affinity, binding specificity, and enzymatic stability relative to conventional α-L-LNA. The results from the back-to-back articles therefore suggest that C5-functionalization of pyrimidines is a general and synthetically straightforward approach to modulate biophysical properties of oligonucleotides modified with LNA or other conformationally restricted monomers.
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Affiliation(s)
- Pawan Kumar
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, United States
- Department of Chemistry, Kurukshetra University, Kurukshetra 136119, India
| | - Bharat Baral
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, United States
| | - Brooke A. Anderson
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, United States
| | - Dale C. Guenther
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, United States
| | - Michael E. Østergaard
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, United States
| | - Pawan K. Sharma
- Department of Chemistry, Kurukshetra University, Kurukshetra 136119, India
| | - Patrick J. Hrdlicka
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, United States
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Seth PP, Swayze EE. Unnatural Nucleoside Analogs for Antisense Therapy. METHODS AND PRINCIPLES IN MEDICINAL CHEMISTRY 2014. [DOI: 10.1002/9783527676545.ch12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Hanessian S, Schroeder BR, Merner BL, Chen B, Swayze EE, Seth PP. Synthesis of cis- and trans-α-l-[4.3.0]bicyclo-DNA monomers for antisense technology: methods for the diastereoselective formation of bicyclic nucleosides. J Org Chem 2013; 78:9051-63. [PMID: 23937280 DOI: 10.1021/jo401166q] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Two α-L-ribo-configured bicyclic nucleic acid modifications, represented by analogues 12 and 13, which are epimeric at C3' and C5' have been synthesized using a carbohydrate-based approach to build the bicyclic core structure. An intramolecular L-proline-mediated aldol reaction was employed to generate the cis-configured ring junction of analogue 12 and represents a rare application of this venerable organocatalytic reaction to a carbohydrate system. In the case of analogue 13, where a trans-ring junction was desired, an intermolecular diastereoselective Grignard reaction followed by ring-closing metathesis was used. In order to set the desired stereochemistry at the C5' positions of both nucleoside targets, a study of diastereoselective Lewis acid mediated allylation reactions on a common bicyclic aldehyde precursor was carried out. Analogue 12 was incorporated in oligonucleotide sequences, and thermal denaturation experiments indicate that it is destabilizing when paired with complementary DNA and RNA. However, this construct shows a significant improvement in nuclease stability relative to a DNA oligonucleotide.
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Affiliation(s)
- Stephen Hanessian
- Department of Chemistry, Université de Montréal , Montréal, Québec H3C 3J7, Canada
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Seth PP, Jazayeri A, Yu J, Allerson CR, Bhat B, Swayze EE. Structure Activity Relationships of α-L-LNA Modified Phosphorothioate Gapmer Antisense Oligonucleotides in Animals. MOLECULAR THERAPY. NUCLEIC ACIDS 2012; 1:e47. [PMID: 23344239 PMCID: PMC3499693 DOI: 10.1038/mtna.2012.34] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We report the structure activity relationships of short 14-mer phosphorothioate gapmer antisense oligonucleotides (ASOs) modified with α-L-locked nucleic acid (LNA) and related modifications targeting phosphatase and tensin homologue (PTEN) messenger RNA in mice. α-L-LNA represents the α-anomer of enantio-LNA and modified oligonucleotides show LNA like binding affinity for complementary RNA. In contrast to sequence matched LNA gapmer ASOs which showed elevations in plasma alanine aminotransferase (ALT) levels indicative of hepatotoxicity, gapmer ASOs modified with α-L-LNA and related analogs in the flanks showed potent downregulation of PTEN messenger RNA in liver tissue without producing elevations in plasma ALT levels. However, the α-L-LNA ASO showed a moderate dose-dependent increase in liver and spleen weights suggesting a higher propensity for immune stimulation. Interestingly, replacing α-L-LNA nucleotides in the 3′- and 5′-flanks with R-5′-Me-α-L-LNA but not R-6′-Me- or 3′-Me-α-L-LNA nucleotides, reversed the drug induced increase in organ weights. Examination of structural models of dinucleotide units suggested that the 5′-Me group increases steric bulk in close proximity to the phosphorothioate backbone or produces subtle changes in the backbone conformation which could interfere with recognition of the ASO by putative immune receptors. Our data suggests that introducing steric bulk at the 5′-position of the sugar-phosphate backbone could be a general strategy to mitigate the immunostimulatory profile of oligonucleotide drugs. In a clinical setting, proinflammatory effects manifest themselves as injection site reactions and flu-like symptoms. Thus, a mitigation of these effects could increase patient comfort and compliance when treated with ASOs.
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Zhou C, Chattopadhyaya J. Intramolecular free-radical cyclization reactions on pentose sugars for the synthesis of carba-LNA and carba-ENA and the application of their modified oligonucleotides as potential RNA targeted therapeutics. Chem Rev 2012; 112:3808-32. [PMID: 22530946 DOI: 10.1021/cr100306q] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Chuanzheng Zhou
- Chemical Biology Program, Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Sweden
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Seth PP, Allerson CR, Ostergaard ME, Swayze EE. Structural requirements for hybridization at the 5'-position are different in α-l-LNA as compared to β-D-LNA. Bioorg Med Chem Lett 2011; 22:296-9. [PMID: 22153935 DOI: 10.1016/j.bmcl.2011.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 11/02/2011] [Accepted: 11/03/2011] [Indexed: 01/02/2023]
Abstract
The synthesis and biophysical evaluation of R and S-5'-Me-α-l-LNA nucleoside phosphoramidites and modified oligo-2'-deoxyribonucleotides is reported. Synthesis of the nucleoside phosphoramidites was accomplished in multi-gram quantities starting from diacetone glucose. The 5'-methyl group in the S configuration was introduced by reacting the sugar 5'-aldehyde with MeMgBr. Synthesis of the R-5'-Me isomer was accomplished from the S-5'-Me nucleoside by a late stage inversion using Mitsunobu conditions. Evaluation of the modified oligonucleotides in thermal denaturation experiments revealed that R-5'-Me-α-l-LNA showed similar RNA affinity as α-l-LNA while the S-5'-Me analog was less stabilizing. This result is in contrast to the β-d-series where the S-5'-Me isomer showed LNA-like affinity for RNA while the R-5'-Me group completely reversed the stabilization effect on duplex thermostability.
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Affiliation(s)
- Punit P Seth
- Department of Medicinal Chemistry, Isis Pharmaceuticals, 2855 Gazelle Court, Carlsbad, CA 92010, USA.
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Seth PP, Allerson CA, Østergaard ME, Swayze EE. Synthesis and biophysical evaluation of 3'-Me-α-L-LNA - Substitution in the minor groove of α-L-LNA duplexes. Bioorg Med Chem Lett 2011; 21:4690-4. [PMID: 21778053 DOI: 10.1016/j.bmcl.2011.06.104] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 06/22/2011] [Accepted: 06/24/2011] [Indexed: 10/18/2022]
Abstract
The synthesis and biophysical evaluation of 3'-Me-α-L-LNA is reported. The synthesis of the nucleoside building block phosphoramidite was accomplished starting from diacetone glucose. The 3'-Me group was introduced in the desired configuration by hydride mediated opening of an exocyclic epoxide. Inversion of the 2'-hydroxyl group was achieved by means of an oxidation/reduction sequence followed by cyclization onto a 5'-leaving group to assemble the [2.2.1] ring system. Biophysical evaluation of 3'-Me-α-L-LNA modified oligonucleotides showed good duplex thermal stabilizing properties which were similar to α-L-LNA. Mismatch discrimination experiments revealed that 3'-Me-α-L-LNA possess slightly enhanced discrimination properties for the GU wobble base-pair as compared to related nucleic acid analogs.
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Affiliation(s)
- Punit P Seth
- Department of Medicinal Chemistry, Isis Pharmaceuticals, 1891 Rutherford Road, Carlsbad, CA 92008, United States.
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Seth PP, Yu J, Allerson CR, Berdeja A, Swayze EE. Synthesis and biophysical characterization of R-6'-Me-α-L-LNA modified oligonucleotides. Bioorg Med Chem Lett 2010; 21:1122-5. [PMID: 21256012 DOI: 10.1016/j.bmcl.2010.12.119] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 12/22/2010] [Accepted: 12/23/2010] [Indexed: 12/28/2022]
Abstract
The synthesis and biophysical properties of R-6'-Me-α-L-LNA, which has a methyl group in the (R) configuration on the 2',4'-bridging substituent of α-L-LNA, is reported. The synthesis of the uracil nucleobase phosphoramidite was efficiently accomplished in 14 steps and 8 chromatographic purifications starting from a known sugar intermediate. Biophysical evaluation revealed that substitution along the edge of the major groove does not impair the high affinity duplex forming ability of α-L-LNA modified oligonucleotides.
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Affiliation(s)
- Punit P Seth
- Department of Medicinal Chemistry, Isis Pharmaceuticals, 1891 Rutherford Road, Carlsbad, CA 92008, USA.
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