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Jew SS, Park BS, Lim DY, Kim MG, Chung IK, Kim JH, Hong CI, Kim JK, Park HJ, Lee JH, Park HG. Synthesis of 6-formyl-pyridine-2-carboxylate derivatives and their telomerase inhibitory activities. Bioorg Med Chem Lett 2003; 13:609-12. [PMID: 12639541 DOI: 10.1016/s0960-894x(02)01041-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Twenty-one pyridine-2-carboxylate derivatives were prepared by the coupling of 6-formyl-2-carboxylic acid with the corresponding phenol, thiophenol, and aniline, substituted with various functional groups. Among them, the 3,4-dichlorothiophenol ester (9p) showed the highest in vitro telomerase inhibitory activity and quite significant in vivo tumor suppression activity.
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Affiliation(s)
- Sang-sup Jew
- Research Institute of Pharmaceutical Sciences and College of Pharmacy, Seoul National University, Seoul 151-742, South Korea.
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2
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Affiliation(s)
- A J Davis
- Department of Medical Oncology and Hematology, Princess Margaret Hospital/The Toronto Hospital, Ontario, Canada
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3
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Braasch DA, Corey DR. Synthesis, analysis, purification, and intracellular delivery of peptide nucleic acids. Methods 2001; 23:97-107. [PMID: 11181029 DOI: 10.1006/meth.2000.1111] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Peptide nucleic acids (PNAs) are nonionic DNA mimics. Their novel chemical properties may facilitate the development of selective and potent antisense and antigene strategies for regulating intracellular processes. Described herein are procedures for the synthesis, purification, handling, and characterization of PNAs. A simple protocol for the lipid-mediated introduction of PNAs into in vitro cultures of mammalian cells is provided.
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Affiliation(s)
- D A Braasch
- Department of Pharmacology, Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9041, USA
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Jen KY, Gewirtz AM. Suppression of gene expression by targeted disruption of messenger RNA: available options and current strategies. Stem Cells 2000; 18:307-19. [PMID: 11007915 DOI: 10.1634/stemcells.18-5-307] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
At least three different approaches may be used for gene targeting including: A) gene knockout by homologous recombination; B) employment of synthetic oligonucleotides capable of hybridizing with DNA or RNA, and C) use of polyamides and other natural DNA-bonding molecules called lexitropsins. Targeting mRNA is attractive because mRNA is more accessible than the corresponding gene. Three basic strategies have emerged for this purpose, the most familiar being to introduce antisense nucleic acids into a cell in the hopes that they will form Watson-Crick base pairs with the targeted gene's mRNA. Duplexed mRNA cannot be translated, and almost certainly initiates processes which lead to its destruction. The antisense nucleic acid can take the form of RNA expressed from a vector which has been transfected into the cell, or take the form of a DNA or RNA oligonucleotide which can be introduced into cells through a variety of means. DNA and RNA oligonucleotides can be modified for stability as well as engineered to contain inherent cleaving activity. It has also been proven that because RNA and DNA are very similar chemical compounds, DNA molecules with enzymatic activity could also be developed. This assumption proved correct and led to the development of a "general-purpose" RNA-cleaving DNA enzyme. The attraction of DNAzymes over ribozymes is that they are very inexpensive to make and that because they are composed of DNA and not RNA, they are inherently more stable than ribozymes. Although mRNA targeting is impeccable in theory, many additional considerations must be taken into account in applying these strategies in living cells including mRNA site selection, drug delivery and intracellular localization of the antisense agent. Nevertheless, the ongoing revolution in cell and molecular biology, combined with advances in the emerging disciplines of genomics and informatics, has made the concept of nontoxic, cancer-specific therapies more viable then ever and continues to drive interest in this field.
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Affiliation(s)
- K Y Jen
- Department of Cell and Molecular Biology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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5
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Abstract
In the past decade, a great deal has been learnt about the maintenance of telomeres in mammalian cells by the specialized reverse transcriptase, telomerase, and its associated proteins. The catalytic component of telomerase, hTERT, appears to be selectively activated in the vast majority of tumors relative to most somatic cells suggesting that its inhibition may result in antitumor effects. Although beset with some unusual issues as a drug target, recent 'target validation' studies using hTERT dominant-negative and antisense approaches strongly support the view that potent and selective telomerase inhibitors will induce inhibitory effects on tumors, especially in those possessing relatively short telomeres. Inhibitory strategies have focused on three main areas: antisense molecules (oligonucleotides, RNA molecules, ribozymes and peptide nucleic acids) directed against the hTR RNA component of telomerase, small molecule reverse transcriptase inhibitors (e.g. azidothymidine), and, probably most advanced, small molecules capable of interacting with and stabilizing four-stranded (G-quadruplex) structures formed by telomeres. G-quadruplex interactive agents that inhibit telomerase at sub-micromolar concentrations in cell-free assays have been described. Lead optimization and preclinical whole-cell and animal antitumor and pharmacology studies are now progressing which should result in the first generation of telomerase inhibitors being evaluated in the clinic within the next few years.
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Affiliation(s)
- L R Kelland
- CRC Centre for Cancer Therapeutics, The Institute of Cancer Research, Sutton, Surrey, UK.
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6
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Szatmari I, Tókés S, Dunn CB, Bardos TJ, Aradi J. Modified telomeric repeat amplification protocol: a quantitative radioactive assay for telomerase without using electrophoresis. Anal Biochem 2000; 282:80-8. [PMID: 10860502 DOI: 10.1006/abio.2000.4589] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A polymerase chain reaction (PCR)-based radioactive telomerase assay was developed in our laboratory which is quantitative and does not require electrophoretic evaluation (designated as TP-TRAP; it utilizes two reverse primers). The main steps of the assay include (1) extension of a 20-mer oligonucleotide substrate (MTS) by telomerase, (2) amplification of the telomerase products in the presence of [(3)H]dTTP using the substrate oligonucleotide and two reverse primers (RPC3, 38 mer; RP, 20 mer), (3) isolation of the amplified radioactive dsDNA by precipitation and filtration, (4) determination of the radioactivity of the acid-insoluble DNA. The length of the telomerase products does not increase on amplification. This valuable feature of the assay is achieved by utilization of the two reverse primers and a highly specific PCR protocol. The assay is linear, accurate, and suitable for cell-biological studies where slight quantitative differences in telomerase activity must be detected. The assay is also suitable for screening and characterization of telomerase inhibitors, as shown with a chemically modified oligonucleotide reverse transcriptase inhibitor [(s(4)dU)(35)].
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Affiliation(s)
- I Szatmari
- Department of Biochemistry and Molecular Biology, University Medical School of Debrecen, Debrecen, H-4012, Hungary
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Hamilton SE, Simmons CG, Kathiriya IS, Corey DR. Cellular delivery of peptide nucleic acids and inhibition of human telomerase. CHEMISTRY & BIOLOGY 1999; 6:343-51. [PMID: 10375543 DOI: 10.1016/s1074-5521(99)80046-5] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Human telomerase has an essential RNA component and is an ideal target for developing rules correlating oligonucleotide chemistry with disruption of biological function. Similarly, peptide nucleic acids (PNAs), DNA analogs that bind complementary sequences with high affinity, are outstanding candidates for inducing phenotypic changes through hybridization. RESULTS We identify PNAs directed to nontemplate regions of the telomerase RNA that can overcome RNA secondary structure and inhibit telomerase by intercepting the RNA component prior to holoenzyme assembly. Relative potencies of inhibition delineate putative structural domains. We describe a novel protocol for introducing PNAs into eukaryotic cells and report efficient inhibition of cellular telomerase by PNAs. CONCLUSIONS PNAs directed to nontemplate regions are a new class of telomerase inhibitor and may contribute to the development of novel antiproliferative agents. The dependence of inhibition by nontemplate-directed PNAs on target sequence suggests that PNAs have great potential for mapping nucleic acid structure and predictably regulating biological processes. Our simple method for introducing PNAs into cells will not only be useful for probing the complex biology surrounding telomere length maintenance but can be broadly applied for controlling gene expression and functional genomics.
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Affiliation(s)
- S E Hamilton
- Howard Hughes Medical Institute Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75235-9050, USA
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9
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Abstract
Telomerase is a ribonucleoprotein that is responsible for maintaining telomere length. The observation that telomerase activity is found in many types of tumors, but not in adjacent normal tissue, has led to the hypothesis that telomerase is a novel target for chemotherapy. Inhibitors of telomerase activity are essential to validate this hypothesis, and their design presents special opportunities and challenges.
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Perry PJ, Reszka AP, Wood AA, Read MA, Gowan SM, Dosanjh HS, Trent JO, Jenkins TC, Kelland LR, Neidle S. Human telomerase inhibition by regioisomeric disubstituted amidoanthracene-9,10-diones. J Med Chem 1998; 41:4873-84. [PMID: 9822556 DOI: 10.1021/jm981067o] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Telomerase is an attractive target for the design of new anticancer drugs. We have previously described a series of 1,4- and 2, 6-difunctionalized amidoanthracene-9,10-diones that inhibit human telomerase via stabilization of telomeric G-quadruplex structures. The present study details the preparation of three further, distinct series of regioisomeric difunctionalized amidoanthracene-9,10-diones substituted at the 1,5-, 1,8-, and 2,7-positions, respectively. Their in vitro cytotoxicity and Taq DNA polymerase and human telomerase inhibition properties are reported and compared with those of their 1,4- and 2,6-isomers. Potent telomerase inhibition (telIC50 values 1.3-17.3 microM) is exhibited within each isomeric series. In addition, biophysical and molecular modeling studies have been conducted to examine binding to the target G-quadruplex structure formed by the folding of telomeric DNA. These studies indicate that the isomeric diamidoanthracene-9,10-diones bind to the human telomeric G-quadruplex structure with a stoichiometry of 1:1. Plausible G-quadruplex-ligand complexes have been identified for each isomeric family, with three distinct modes of intercalative binding being proposed. The exact mode of intercalative binding is dictated by the positional placement of substituent side chains. Furthermore, in contrast to previous studies directed toward triplex DNA, it is evident that stringent control over positional attachment of substituents is not a necessity for effective telomerase inhibition.
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Affiliation(s)
- P J Perry
- Cancer Research Campaign Biomolecular Structure Unit and Centre for Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, UK
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11
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Abstract
Telomerase, a ribonucleoprotein up-regulated in many types of cancers, possesses an RNA template necessary to bind and extend telomere ends. The intrinsic accessibility of telomerase to incoming nucleic acids makes the RNA template an ideal target for inhibition by oligonucleotides. We report here that 2'-O-methyl-RNA (2'-O-meRNA), an oligonucleotide chemistry known to exert sequence-specific effects in cell culture and animals, inhibits telomerase with potencies superior to those possessed by analogous peptide nucleic acids (PNAs). Potent inhibition relative to PNAs is surprising, because the binding affinity of 2'-O-meRNAs for complementary RNA is low relative to analogous PNAs. A 2'-O-meRNA oligomer with terminal phosphorothioate substitutions inhibits telomerase sequence-selectively within human-tumor-derived DU145 cells when delivered with cationic lipids. In contrast to the ability of 2'-O-meRNA oligomers to inhibit telomerase, the binding of a 2'-O-meRNA to an inverted repeat within plasmid DNA was not detectable, whereas binding of PNA was efficient, suggesting that the relative accessibility of the telomerase RNA template is essential for inhibition by 2'-O-meRNA. Inhibition of telomerase by 2'-O-meRNA will facilitate probing the link between telomerase activity and sustained cell proliferation and may provide a basis for the development of chemopreventive and chemotherapeutic agents.
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Affiliation(s)
- A E Pitts
- Howard Hughes Medical Institute, Departments of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75235-9050, USA
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Perry PJ, Gowan SM, Reszka AP, Polucci P, Jenkins TC, Kelland LR, Neidle S. 1,4- and 2,6-disubstituted amidoanthracene-9,10-dione derivatives as inhibitors of human telomerase. J Med Chem 1998; 41:3253-60. [PMID: 9703471 DOI: 10.1021/jm9801105] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A number of 1,4- and 2,6-difunctionalized amidoanthracene-9, 10-diones have been prepared. We have examined their in vitro cytotoxicity in several tumor cell lines and their ability to inhibit the telomere-addition function of the human telomerase enzyme together with their inhibition of the Taq polymerase enzyme. Compounds with -(CH2)2- side chains terminating in basic groups such as piperidine show inhibition of telomerase at telIC50 levels of 4-11 microM. These are thus among the most potent nonnucleoside telomerase inhibitors reported to date. Cytotoxicity levels in human tumor cell lines were at comparable levels for several compounds. Implications for amidoanthracene-9,10-dione telomerase inhibitors as potential anticancer agents are discussed.
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Affiliation(s)
- P J Perry
- Cancer Research Campaign Biomolecular Structure Unit and Centre for Cancer Therapeutics, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
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Sharma S, Raymond E, Soda H, Sun D, Hilsenbeck SG, Sharma A, Izbicka E, Windle B, Von Hoff DD. Preclinical and clinical strategies for development of telomerase and telomere inhibitors. Ann Oncol 1997; 8:1063-74. [PMID: 9426325 DOI: 10.1023/a:1008206420505] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Telomerase is an important enzyme whose activity has been convincingly demonstrated in humans recently. It is required for maintenance of ends of chromosomes (telomeres) during cell division. Since its presence has been selectively demonstrated in dividing cells including tumor cells, it has generated considerable excitement as a potential anti-cancer strategy. DESIGN In this article, we review the current relevant biology of the enzyme, the challenges encountered in the preclinical phase of target development and the current efforts that focus on telomeres and telomerase as therapeutic targets. We also speculate on the potential toxicities and mechanisms of resistance that may be encountered during use of such therapies.
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Affiliation(s)
- S Sharma
- Institute for Drug Development, University of Texas Health Science Center, San Antonio, USA
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