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Agarwal T, Pradhan D, Géci I, El-Madani AM, Petersen M, Pedersen EB, Maiti S. Improved inhibition of telomerase by short twisted intercalating nucleic acids under molecular crowding conditions. Nucleic Acid Ther 2012; 22:399-404. [PMID: 23098240 DOI: 10.1089/nat.2012.0372] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human telomeric DNA has the ability to fold into a 4-stranded G-quadruplex structure. Several G-quadruplex ligands are known to stabilize the structure and thereby inhibit telomerase activity. Such ligands have demonstrated efficient telomerase inhibition in dilute conditions, but under molecular crowding conditions mimicking physiological milieu, stabilization of the telomeric G-quadruplex is often lost. We attempted to demonstrate the enhanced G-quadruplex stabilizing ability under molecular conditions by using twisted intercalating nucleic acids (TINA)-modified oligonucleotides. We have shown using circular dichroism and ultraviolet spectroscopic methods that these TINA-modified short oligonucleotides function as G-quadruplex, inducing agents and participate in the formation of stabilized 3:1 G-quadruplex with the human telomeric oligonucleotide. Using enzyme-linked immunosorbent assay-based telomerase repeat amplification assay (TRAP) assay as well as nondenaturing polyacrylamide gel electrophoresis-based TRAP, we demonstrate remarkable enhancement in their anti-telomerase activity even under molecular crowding conditions. This is the first time in which a G-quadruplex stabilizing agent has demonstrated enhanced activity even under molecular crowding conditions.
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Affiliation(s)
- Tani Agarwal
- Proteomics and Structural Biology Unit, Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, New Delhi, India
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G-ruption: the third international meeting on G-quadruplex and G-assembly. Biochimie 2012; 94:2475-83. [PMID: 22974982 DOI: 10.1016/j.biochi.2012.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 09/04/2012] [Indexed: 12/31/2022]
Abstract
A three and a half day conference focusing on nucleic acid structures called G-quadruplexes (G4s) and other guanine-based assemblies was held in Sorrento, Italy (June 28-July 1, 2011) and featured 35 invited talks and over 89 posters. The G-quadruplex field continues to expand at an explosive rate with the emergence of new connections to biology, chemistry, physics, and nanotechnology. Following the trend established by the previous two international G4 meetings, the conference touched upon all these areas and facilitated productive exchanges of ideas between researchers from all over the world.
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Doluca O, Boutorine AS, Filichev VV. Triplex-Forming Twisted Intercalating Nucleic Acids (TINAs): Design Rules, Stabilization of Antiparallel DNA Triplexes and Inhibition of G-Quartet-Dependent Self-Association. Chembiochem 2011; 12:2365-74. [DOI: 10.1002/cbic.201100354] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Pedersen EB, Nielsen JT, Nielsen C, Filichev VV. Enhanced anti-HIV-1 activity of G-quadruplexes comprising locked nucleic acids and intercalating nucleic acids. Nucleic Acids Res 2011; 39:2470-81. [PMID: 21062811 PMCID: PMC3064782 DOI: 10.1093/nar/gkq1133] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 10/21/2010] [Accepted: 10/22/2010] [Indexed: 01/23/2023] Open
Abstract
Two G-quadruplex forming sequences, 5'-TGGGAG and the 17-mer sequence T30177, which exhibit anti-HIV-1 activity on cell lines, were modified using either locked nucleic acids (LNA) or via insertions of (R)-1-O-(pyren-1-ylmethyl)glycerol (intercalating nucleic acid, INA) or (R)-1-O-[4-(1-pyrenylethynyl)phenylmethyl]glycerol (twisted intercalating nucleic acid, TINA). Incorporation of LNA or INA/TINA monomers provide as much as 8-fold improvement of anti-HIV-1 activity. We demonstrate for the first time a detailed analysis of the effect the incorporation of INA/TINA monomers in quadruplex forming oligonucleotides (QFOs) and the effect of LNA monomers in the context of biologically active QFOs. In addition, recent literature reports and our own studies on the gel retardation of the phosphodiester analogue of T30177 led to the conclusion that this sequence forms a parallel, dimeric G-quadruplex. Introduction of the 5'-phosphate inhibits dimerisation of this G-quadruplex as a result of negative charge-charge repulsion. Contrary to that, we found that attachment of the 5'-O-DMT-group produced a more active 17-mer sequence that showed signs of aggregation-forming multimeric G-quadruplex species in solution. Many of the antiviral QFOs in the present study formed more thermally stable G-quadruplexes and also high-order G-quadruplex structures which might be responsible for the increased antiviral activity observed.
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Affiliation(s)
- Erik B. Pedersen
- Nucleic Acid Center, Department of Physics and Chemistry, University of Southern Denmark, 5230 Odense, Department of Virology, Retrovirus Laboratory, State Serum Institute, 2300 Copenhagen, Denmark and Institute of Fundamental Sciences, Massey University, Palmerston North, Private Bag 11-222, New Zealand
| | - Jakob T. Nielsen
- Nucleic Acid Center, Department of Physics and Chemistry, University of Southern Denmark, 5230 Odense, Department of Virology, Retrovirus Laboratory, State Serum Institute, 2300 Copenhagen, Denmark and Institute of Fundamental Sciences, Massey University, Palmerston North, Private Bag 11-222, New Zealand
| | - Claus Nielsen
- Nucleic Acid Center, Department of Physics and Chemistry, University of Southern Denmark, 5230 Odense, Department of Virology, Retrovirus Laboratory, State Serum Institute, 2300 Copenhagen, Denmark and Institute of Fundamental Sciences, Massey University, Palmerston North, Private Bag 11-222, New Zealand
| | - Vyacheslav V. Filichev
- Nucleic Acid Center, Department of Physics and Chemistry, University of Southern Denmark, 5230 Odense, Department of Virology, Retrovirus Laboratory, State Serum Institute, 2300 Copenhagen, Denmark and Institute of Fundamental Sciences, Massey University, Palmerston North, Private Bag 11-222, New Zealand
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Zaghloul EM, Madsen AS, Moreno PMD, Oprea II, El-Andaloussi S, Bestas B, Gupta P, Pedersen EB, Lundin KE, Wengel J, Smith CIE. Optimizing anti-gene oligonucleotide 'Zorro-LNA' for improved strand invasion into duplex DNA. Nucleic Acids Res 2010; 39:1142-54. [PMID: 20860997 PMCID: PMC3035455 DOI: 10.1093/nar/gkq835] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Zorro-LNA (Zorro) is a newly developed, oligonucleotide (ON)-based, Z-shaped construct with the potential of specific binding to each strand of duplex DNA. The first-generation Zorros are formed by two hybridized LNA/DNA mixmers (2-ON Zorros) and was hypothesized to strand invade. We have now established a method, which conclusively demonstrates that an LNA ON can strand invade into duplex DNA. To make Zorros smaller in size and easier to design, we synthesized 3′–5′–5′–3′ single-stranded Zorro-LNA (ssZorro) by using both 3′- and 5′-phosphoramidites. With ssZorro, a significantly greater extent and rate of double-strand invasion (DSI) was obtained than with conventional 2-ON Zorros. Introducing hydrophilic PEG-linkers connecting the two strands did not significantly change the rate or extent of DSI as compared to ssZorro with a nucleotide-based linker, while the longest alkyl-chain linker tested (36 carbons) resulted in a very slow DSI. The shortest alkyl-chain linker (3 carbons) did not reduce the extent of DSI of ssZorro, but significantly decreased the DSI rate. Collectively, ssZorro is smaller in size, easier to design and more efficient than conventional 2-ON Zorro in inducing DSI. Analysis of the chemical composition of the linker suggests that it could be of importance for future therapeutic considerations.
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Affiliation(s)
- Eman M Zaghloul
- Department of Laboratory Medicine, Karolinska Institutet, 141 86 Huddinge, Stockholm, Sweden.
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Schneider UV, Mikkelsen ND, Jøhnk N, Okkels LM, Westh H, Lisby G. Optimal design of parallel triplex forming oligonucleotides containing Twisted Intercalating Nucleic Acids--TINA. Nucleic Acids Res 2010; 38:4394-403. [PMID: 20338879 PMCID: PMC2910062 DOI: 10.1093/nar/gkq188] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Twisted intercalating nucleic acid (TINA) is a novel intercalator and stabilizer of Hoogsteen type parallel triplex formations (PT). Specific design rules for position of TINA in triplex forming oligonucleotides (TFOs) have not previously been presented. We describe a complete collection of easy and robust design rules based upon more than 2500 melting points (Tm) determined by FRET. To increase the sensitivity of PT, multiple TINAs should be placed with at least 3 nt in-between or preferable one TINA for each half helixturn and/or whole helixturn. We find that ΔTm of base mismatches on PT is remarkably high (between 7.4 and 15.2°C) compared to antiparallel duplexes (between 3.8 and 9.4°C). The specificity of PT by ΔTm increases when shorter TFOs and higher pH are chosen. To increase ΔTms, base mismatches should be placed in the center of the TFO and when feasible, A, C or T to G base mismatches should be avoided. Base mismatches can be neutralized by intercalation of a TINA on each side of the base mismatch and masked by a TINA intercalating direct 3′ (preferable) or 5′ of it. We predict that TINA stabilized PT will improve the sensitivity and specificity of DNA based clinical diagnostic assays.
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Affiliation(s)
- Uffe V Schneider
- QuantiBact Inc, Department of Clinical Microbiology, Hvidovre Hospital, Kettegaards Alle 30, 2650 Hvidovre, Denmark.
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