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Matić J, Piotrowski P, Vrban L, Kobetić R, Vianello R, Jurić I, Fabijanić I, Pernar Kovač M, Brozovic A, Piantanida I, Schmuck C, Radić Stojković M. Distinctive Nucleic Acid Recognition by Lysine-Embedded Phenanthridine Peptides. Int J Mol Sci 2024; 25:4866. [PMID: 38732083 PMCID: PMC11084427 DOI: 10.3390/ijms25094866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 04/25/2024] [Accepted: 04/27/2024] [Indexed: 05/13/2024] Open
Abstract
Three new phenanthridine peptide derivatives (19, 22, and 23) were synthesized to explore their potential as spectrophotometric probes for DNA and RNA. UV/Vis and circular dichroism (CD) spectra, mass spectroscopy, and computational analysis confirmed the presence of intramolecular interactions in all three compounds. Computational analysis revealed that compounds alternate between bent and open conformations, highlighting the latter's crucial influence on successful polynucleotide recognition. Substituting one glycine with lysine in two regioisomers (22, 23) resulted in stronger binding interactions with DNA and RNA than for a compound containing two glycines (19), thus emphasizing the importance of lysine. The regioisomer with lysine closer to the phenanthridine ring (23) exhibited a dual and selective fluorimetric response with non-alternating AT and ATT polynucleotides and induction of triplex formation from the AT duplex. The best binding constant (K) with a value of 2.5 × 107 M-1 was obtained for the interaction with AT and ATT polynucleotides. Furthermore, apart from distinguishing between different types of ds-DNA and ds-RNA, the same compound could recognize GC-rich DNA through distinct induced CD signals.
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Affiliation(s)
- Josipa Matić
- Laboratory for Biomolecular Interactions and Spectroscopy, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (J.M.); (R.K.); (I.J.); (I.F.); (I.P.)
| | - Patryciusz Piotrowski
- Institute for Organic Chemistry, University of Duisburg-Essen, Universitätsstrasse 7, 45141 Essen, Germany; (P.P.)
| | - Lucija Vrban
- Laboratory for the Computational Design and Synthesis of Functional Materials, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (L.V.); (R.V.)
| | - Renata Kobetić
- Laboratory for Biomolecular Interactions and Spectroscopy, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (J.M.); (R.K.); (I.J.); (I.F.); (I.P.)
| | - Robert Vianello
- Laboratory for the Computational Design and Synthesis of Functional Materials, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (L.V.); (R.V.)
| | - Ivona Jurić
- Laboratory for Biomolecular Interactions and Spectroscopy, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (J.M.); (R.K.); (I.J.); (I.F.); (I.P.)
| | - Ivana Fabijanić
- Laboratory for Biomolecular Interactions and Spectroscopy, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (J.M.); (R.K.); (I.J.); (I.F.); (I.P.)
| | - Margareta Pernar Kovač
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (M.P.K.); (A.B.)
| | - Anamaria Brozovic
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (M.P.K.); (A.B.)
| | - Ivo Piantanida
- Laboratory for Biomolecular Interactions and Spectroscopy, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (J.M.); (R.K.); (I.J.); (I.F.); (I.P.)
| | - Carsten Schmuck
- Institute for Organic Chemistry, University of Duisburg-Essen, Universitätsstrasse 7, 45141 Essen, Germany; (P.P.)
| | - Marijana Radić Stojković
- Laboratory for Biomolecular Interactions and Spectroscopy, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (J.M.); (R.K.); (I.J.); (I.F.); (I.P.)
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Zhan Y, Dai C, Zhu Z, Liu P, Sun P. Electrochemical Decarboxylative Cyclization of α‐Amino‐Oxy Acids to Access Phenanthridine Derivatives. Chem Asian J 2022; 17:e202101388. [DOI: 10.1002/asia.202101388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/17/2022] [Indexed: 11/08/2022]
Affiliation(s)
- Yanling Zhan
- Nanjing Normal University Chemistry Nanjing CHINA
| | - Changhui Dai
- Nanjing Normal University Chemistry Nanjing CHINA
| | - Zitong Zhu
- Nanjing Normal University Chemistry Nanjing CHINA
| | - Ping Liu
- Nanjing Normal University Chemistry Nanjing CHINA
| | - Peipei Sun
- Nanjing Normal University Chemistry Ninghai Road 210097 Nanjing CHINA
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3
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Kamal S, Junaid M, Ejaz A, Bibi I, Akash MSH, Rehman K. The secrets of telomerase: Retrospective analysis and future prospects. Life Sci 2020; 257:118115. [PMID: 32698073 DOI: 10.1016/j.lfs.2020.118115] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/06/2020] [Accepted: 07/13/2020] [Indexed: 12/12/2022]
Abstract
Telomerase plays a significant role to maintain and regulate the telomere length, cellular immortality and senescence by the addition of guanine-rich repetitive sequences. Chronic inflammation or oxidative stress-induced infection downregulates TERT gene modifying telomerase activity thus contributing to the early steps of gastric carcinogenesis process. Furthermore, telomere-telomerase system performs fundamental role in the pathogenesis and progression of diabetes mellitus as well as in its vascular intricacy. The cessation of cell proliferation in cultured cells by inhibiting the telomerase activity of transformed cells renders the rationale for culling of telomerase as a target therapy for the treatment of metabolic disorders and various types of cancers. In this article, we have briefly described the role of immune system and malignant cells in the expression of telomerase with critical analysis on the gaps and potential for future studies. The key findings regarding the secrets of the telomerase summarized in this article will help in future treatment modalities for the prevention of various types of cancers and metabolic disorders notably diabetes mellitus.
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Affiliation(s)
- Shagufta Kamal
- Department of Biochemistry, Government College University Faisalabad, Pakistan
| | - Muhammad Junaid
- Department of Biochemistry, Government College University Faisalabad, Pakistan
| | - Arslan Ejaz
- Department of Biochemistry, Government College University Faisalabad, Pakistan
| | - Ismat Bibi
- Department of Chemistry, Islamia University, Bahawalpur, Pakistan
| | | | - Kanwal Rehman
- Department of Pharmacy, University of Agriculture, Faisalabad, Pakistan.
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4
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Islam MK, Jackson PJM, Thurston DE, Rahman KM. Methylene-linked bis-phenylbenzimidazoles - a new scaffold to target telomeric DNA/RNA hybrid duplex. Org Biomol Chem 2018; 16:4424-4428. [PMID: 29498732 DOI: 10.1039/c7ob02709e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a series of novel methylene-linked bis-phenylbenzimidazoles intercalators that stabilize telomeric DNA/RNA hybrid (tDRH) structures by up to 7.2 °C at a 1 μM ligand concentration while having negligible affinity for DNA/DNA duplexes, although with a low affinity for quadruplex DNA. We have used molecular modelling studies to rationalize this selectivity, concluding that the methylene spacer between the terminal benzimidazole and phenylene moieties plays a key role in facilitating the bis-intercalating process. This scaffold may be used to develop chemical tools or new therapeutics to selectively target the telomeric DNA/RNA duplex without affecting normal genomic DNA.
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Affiliation(s)
- M K Islam
- Institute of Pharmaceutical Science, School of Cancer and Pharmaceutical Sciences, King's College London, London SE1 9NH, UK.
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5
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Gulbrandsen HS, Alfaro JLD, Read ML, Gundersen L. Synthesis of Electron‐Deficient Tetrahydro‐ and Dihydroimidazo[1,2‐
f
]phenanthridines by Microwave‐Mediated IMDAF Reactions. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700180] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
| | | | - Matthew Lovell Read
- Department of Chemistry University of Oslo P. O. Box 1033, Blindern 0315 Oslo Norway
| | - Lise‐Lotte Gundersen
- Department of Chemistry University of Oslo P. O. Box 1033, Blindern 0315 Oslo Norway
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6
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Abstract
Telomerase activity is responsible for the maintenance of chromosome end structures (telomeres) and cancer cell immortality in most human malignancies, making telomerase an attractive therapeutic target. The rationale for targeting components of the telomerase holoenzyme has been strengthened by accumulating evidence indicating that these molecules have extra-telomeric functions in tumour cell survival and proliferation. This Review discusses current knowledge of the biogenesis, structure and multiple functions of telomerase-associated molecules intertwined with recent advances in drug discovery approaches. We also describe the fertile ground available for the pursuit of next-generation small-molecule inhibitors of telomerase.
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Affiliation(s)
- Greg M Arndt
- Australian Cancer Research Foundation (ACRF) Drug Discovery Centre for Childhood Cancer, Children's Cancer Institute Australia, Lowy Cancer Research Centre, University of New South Wales, Randwick, New South Wales 2031, Australia
| | - Karen L MacKenzie
- Personalised Medicine Program, Children's Cancer Institute Australia, Lowy Cancer Research Centre, University of New South Wales, Randwick, New South Wales 2031, Australia
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7
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Chen Y, Zhang Y. Functional and mechanistic analysis of telomerase: An antitumor drug target. Pharmacol Ther 2016; 163:24-47. [DOI: 10.1016/j.pharmthera.2016.03.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/29/2016] [Indexed: 01/26/2023]
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8
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Wong PT, Tang K, Coulter A, Tang S, Baker JR, Choi SK. Multivalent Dendrimer Vectors with DNA Intercalation Motifs for Gene Delivery. Biomacromolecules 2014; 15:4134-45. [DOI: 10.1021/bm501169s] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Pamela T. Wong
- Michigan Nanotechnology Institute for Medicine
and Biological Sciences and ‡Department of
Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Kenny Tang
- Michigan Nanotechnology Institute for Medicine
and Biological Sciences and ‡Department of
Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Alexa Coulter
- Michigan Nanotechnology Institute for Medicine
and Biological Sciences and ‡Department of
Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Shengzhuang Tang
- Michigan Nanotechnology Institute for Medicine
and Biological Sciences and ‡Department of
Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - James R. Baker
- Michigan Nanotechnology Institute for Medicine
and Biological Sciences and ‡Department of
Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Seok Ki Choi
- Michigan Nanotechnology Institute for Medicine
and Biological Sciences and ‡Department of
Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
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9
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Cairns AG, Senn HM, Murphy MP, Hartley RC. Expanding the palette of phenanthridinium cations. Chemistry 2014; 20:3742-51. [PMID: 24677631 PMCID: PMC4164275 DOI: 10.1002/chem.201304241] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 01/03/2014] [Indexed: 01/01/2023]
Abstract
5,6-Disubstituted phenanthridinium cations have a range of redox, fluorescence and biological properties. Some properties rely on phenanthridiniums intercalating into DNA, but the use of these cations as exomarkers for the reactive oxygen species (ROS), superoxide, and as inhibitors of acetylcholine esterase (AChE) do not require intercalation. A versatile modular synthesis of 5,6-disubstituted phenanthridiniums that introduces diversity by Suzuki–Miyaura coupling, imine formation and microwave-assisted cyclisation is presented. Computational modelling at the density functional theory (DFT) level reveals that the novel displacement of the aryl halide by an acyclic N-alkylimine proceeds by an S(N)Ar mechanism rather than electrocyclisation. It is found that the displacement of halide is concerted and there is no stable Meisenheimer intermediate, provided the calculations consistently use a polarisable solvent model and a diffuse basis set.
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Affiliation(s)
- Andrew G Cairns
- WestCHEM School of Chemistry, University of GlasgowGlasgow, G12 8QQ (UK) E-mail:
| | - Hans Martin Senn
- WestCHEM School of Chemistry, University of GlasgowGlasgow, G12 8QQ (UK) E-mail:
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, Wellcome Trust/MRC BuildingCambridge, CB2 0XY (UK)
| | - Richard C Hartley
- WestCHEM School of Chemistry, University of GlasgowGlasgow, G12 8QQ (UK) E-mail:
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10
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Sekaran V, Soares J, Jarstfer MB. Telomere Maintenance as a Target for Drug Discovery. J Med Chem 2013; 57:521-38. [DOI: 10.1021/jm400528t] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Vijay Sekaran
- Division of Chemical Biology
and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Joana Soares
- Division of Chemical Biology
and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Michael B. Jarstfer
- Division of Chemical Biology
and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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11
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Altschuler SE, Croy JE, Wuttke DS. A small molecule inhibitor of Pot1 binding to telomeric DNA. Biochemistry 2012; 51:7833-45. [PMID: 22978652 DOI: 10.1021/bi300365k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Chromosome ends are complex structures, consisting of repetitive DNA sequence terminating in an ssDNA overhang with many associated proteins. Because alteration of the regulation of these ends is a hallmark of cancer, telomeres and telomere maintenance have been prime drug targets. The universally conserved ssDNA overhang is sequence-specifically bound and regulated by Pot1 (protection of telomeres 1), and perturbation of Pot1 function has deleterious effects for proliferating cells. The specificity of the Pot1/ssDNA interaction and the key involvement of this protein in telomere maintenance have suggested directed inhibition of Pot1/ssDNA binding as an efficient means of disrupting telomere function. To explore this idea, we developed a high-throughput time-resolved fluorescence resonance energy transfer (TR-FRET) screen for inhibitors of Pot1/ssDNA interaction. We conducted this screen with the DNA-binding subdomain of Schizosaccharomyces pombe Pot1 (Pot1pN), which confers the vast majority of Pot1 sequence-specificity and is highly similar to the first domain of human Pot1 (hPOT1). Screening a library of ∼20 000 compounds yielded a single inhibitor, which we found interacted tightly with sub-micromolar affinity. Furthermore, this compound, subsequently identified as the bis-azo dye Congo red (CR), was able to competitively inhibit hPOT1 binding to telomeric DNA. Isothermal titration calorimetry and NMR chemical shift analysis suggest that CR interacts specifically with the ssDNA-binding cleft of Pot1, and that alteration of this surface disrupts CR binding. The identification of a specific inhibitor of ssDNA interaction establishes a new pathway for targeted telomere disruption.
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Affiliation(s)
- Sarah E Altschuler
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
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12
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Jain N, Francis S, Friedman SH. Inhibition of therapeutically important polymerases with high affinity bis-intercalators. Bioorg Med Chem Lett 2012; 22:4844-8. [PMID: 22695131 DOI: 10.1016/j.bmcl.2012.05.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 05/02/2012] [Accepted: 05/08/2012] [Indexed: 11/26/2022]
Abstract
We have previously demonstrated that polymerases such as telomerase can be inhibited by molecules (e.g., intercalators) that target the key RNA/DNA duplex substrate. In this work we show that this also holds true for reverse transcriptase, and show that the lead intercalators can be modified to increase inhibition efficacy. Specifically, we use the strategy of multiple simultaneous intercalation, by linking two intercalators with a variable linker. The rationale behind this design is that a specific linker has the potential to increase affinity and specificity for the target duplex. We have synthesized a library of 45 ethidium bis-intercalators in which the distance between intercalators is systematically varied. We observe that members of the dimer library have improved telomerase and reverse transcriptase inhibition, relative to the monomeric leads. We show that this improvement in inhibition over mono-intercalators is most prominent when non-productive sites of inhibitor binding are limited in the assay mix. When this is done, a 400-fold increase in inhibition efficacy is observed.
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Affiliation(s)
- Nitin Jain
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri, 2464 Charlotte Street, Kansas City, MO 64108-2718, United States
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13
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Osadchii SA, Shubin VG, Kozlova LP, Varlamenko VS, Filipenko ML, Boyarskikh UA. Improvement of ways to obtain ethidium bromide and synthesis of ethidium ethyl sulfate, a new fluorescent dye for detection of nucleic acids. RUSS J APPL CHEM+ 2011. [DOI: 10.1134/s107042721109014x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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14
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Zvereva MI, Shcherbakova DM, Dontsova OA. Telomerase: structure, functions, and activity regulation. BIOCHEMISTRY (MOSCOW) 2011; 75:1563-83. [PMID: 21417995 DOI: 10.1134/s0006297910130055] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Telomerase is the enzyme responsible for maintenance of the length of telomeres by addition of guanine-rich repetitive sequences. Telomerase activity is exhibited in gametes and stem and tumor cells. In human somatic cells proliferation potential is strictly limited and senescence follows approximately 50-70 cell divisions. In most tumor cells, on the contrary, replication potential is unlimited. The key role in this process of the system of the telomere length maintenance with involvement of telomerase is still poorly studied. No doubt, DNA polymerase is not capable to completely copy DNA at the very ends of chromosomes; therefore, approximately 50 nucleotides are lost during each cell cycle, which results in gradual telomere length shortening. Critically short telomeres cause senescence, following crisis, and cell death. However, in tumor cells the system of telomere length maintenance is activated. Besides catalytic telomere elongation, independent telomerase functions can be also involved in cell cycle regulation. Inhibition of the telomerase catalytic function and resulting cessation of telomere length maintenance will help in restriction of tumor cell replication potential. On the other hand, formation of temporarily active enzyme via its intracellular activation or due to stimulation of expression of telomerase components will result in telomerase activation and telomere elongation that can be used for correction of degenerative changes. Data on telomerase structure and function are summarized in this review, and they are compared for evolutionarily remote organisms. Problems of telomerase activity measurement and modulation by enzyme inhibitors or activators are considered as well.
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Affiliation(s)
- M I Zvereva
- Faculty of Chemistry, Lomonosov Moscow State University, Russia.
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Prunkl C, Pichlmaier M, Winter R, Kharlanov V, Rettig W, Wagenknecht HA. Optical, Redox, and DNA-Binding Properties of Phenanthridinium Chromophores: Elucidating the Role of the Phenyl Substituent for Fluorescence Enhancement of Ethidium in the Presence of DNA. Chemistry 2010; 16:3392-402. [DOI: 10.1002/chem.200902823] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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17
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Abstract
The DNA x RNA hybrid duplexes are functionally important structures in gene expression that are underutilized as potential drug targets. Several tools are described here for the discovery and characterization of small molecules capable of the selective recognition of DNA x RNA hybrid structures. Competition dialysis and thermal denaturation of mixtures of polynucleotide structures can be used to identify small molecules that bind selectively to DNA x RNA hybrids. An assay that measures small molecule inhibition of RNase H can be used to measure a functional response to these ligands.
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Affiliation(s)
| | - Jonathan B. Chaires
- James Graham Brown Cancer Center, University of Louisville, 529 S. Jackson St., Louisville, KY 40202 USA
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Abstract
Bacterial ribosomal RNA is the target of clinically important antibiotics, while biologically important RNAs in viral and eukaryotic genomes present a range of potential drug targets. The physicochemical properties of RNA present difficulties for medicinal chemistry, particularly when oral availability is needed. Peptidic ligands and analysis of their RNA-binding properties are providing insight into RNA recognition. RNA-binding ligands include far more chemical classes than just aminoglycosides. Chemical functionalities from known RNA-binding small molecules are being exploited in fragment- and ligand-based projects. While targeting of RNA for drug design is very challenging, continuing advances in our understanding of the principles of RNA–ligand interaction will be necessary to realize the full potential of this class of targets.
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Akbay N, Seferoğlu Z, Gök E. Fluorescence interaction and determination of calf thymus DNA with two ethidium derivatives. J Fluoresc 2009; 19:1045-51. [PMID: 19557506 DOI: 10.1007/s10895-009-0504-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 06/05/2009] [Indexed: 10/20/2022]
Abstract
In this paper, we reported the syntheses and investigation of the modes of binding to DNA of the two new ethidium derivatives containing benzoyl and phenylacetyl groups of both amines at 3-and 8- positions. The interactions between calf thymus DNA (ct-DNA) and the two derivatives, 3,8-dibenzoylamino-5-ethyl-6-phenylphenantridinium cloride (E2) and 3,8-diphenylacetylamino-5-ethyl-6-phenylphenantridinium chloride (E3), were investigated by fluorescence quenching spectra and UV-vis absorption spectra. The Stern-Volmer quenching constants, binding constants, binding sites and the corresponding thermodynamic parameters DeltaH, DeltaS and DeltaG were calculated at different temperatures. The results indicated the formation of E2 and E3-DNA complexes and van der Waals interactions as the predominant intermolecular forces in stabilizing for each complex. In addition, increasing nucleophilicity of the functional groups at 3- and 8- positions exhibited the respectable increment the DNA binding affinities of derivatives. The results of absorption, ionic strength and iodide ion quenching suggested that the interaction mode of E2 and E3 with ct-DNA was intercalative binding. The limit of detection (LOD) of ct-DNA were 7.49 x 10(-8) (n = 4) and 4.18 x 10(-8) mol/l (n = 7) in presence of E2 and E3, respectively.
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Affiliation(s)
- Nuriye Akbay
- Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara, Turkey
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Guilbert C, James TL. Docking to RNA via root-mean-square-deviation-driven energy minimization with flexible ligands and flexible targets. J Chem Inf Model 2008; 48:1257-68. [PMID: 18510306 DOI: 10.1021/ci8000327] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Structure-based drug design is now well-established for proteins as a key first step in the lengthy process of developing new drugs. In many ways, RNA may be a better target to treat disease than a protein because it is upstream in the translation pathway, so inhibiting a single mRNA molecule could prevent the production of thousands of protein gene products. Virtual screening is often the starting point for structure-based drug design. However, computational docking of a small molecule to RNA seems to be more challenging than that to protein due to the higher intrinsic flexibility and highly charged structure of RNA. Previous attempts at docking to RNA showed the need for a new approach. We present here a novel algorithm using molecular simulation techniques to account for both nucleic acid and ligand flexibility. In this approach, with both the ligand and the receptor permitted some flexibility, they can bind one another via an induced fit, as the flexible ligand probes the surface of the receptor. A possible ligand can explore a low-energy path at the surface of the receptor by carrying out energy minimization with root-mean-square-distance constraints. Our procedure was tested on 57 RNA complexes (33 crystal and 24 NMR structures); this is the largest data set to date to reproduce experimental RNA binding poses. With our procedure, the lowest-energy conformations reproduced the experimental binding poses within an atomic root-mean-square deviation of 2.5 A for 74% of tested complexes.
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Affiliation(s)
- Christophe Guilbert
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158-2517, USA
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21
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Tárkányi I, Aradi J. Pharmacological intervention strategies for affecting telomerase activity: future prospects to treat cancer and degenerative disease. Biochimie 2007; 90:156-72. [PMID: 17945408 DOI: 10.1016/j.biochi.2007.09.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Accepted: 09/04/2007] [Indexed: 12/20/2022]
Abstract
Telomerase enzyme is a ribonucleoprotein maintaining the length of the telomeres by adding G-rich repeats to the end of the eukaryotic chromosomes. Normal human somatic cells, cultured in vitro, have a strictly limited proliferative potential undergoing senescence after about 50-70 population doublings. In contrast, most of the tumor cells have unlimited replicative potential. Although the mechanisms of immortalization are not understood completely at a genetic level, the key role of the telomere/telomerase system in the process is clear. The DNA replication machinery is not able to replicate fully the DNA at the very end of the chromosomes; therefore, about 50-200 nucleotides are lost during each of the replication cycles resulting in a gradual decrease of telomere length. Critically short telomere induces senescence, subsequent crisis and cell death. In tumor cells, however, the telomerase enzyme prevents the formation of critically short telomeres, adding GGTTAG repeats to the 3' end of the chromosomes immortalizing the cells. Immortality is one of the hallmarks of cancer. Besides the catalytic activity dependent telomere maintenance, catalytic activity-independent effects of telomerase may also be involved in the regulation of cell cycle. The telomere/telomerase system offers two possibilities to intervene the proliferative activity of the cell: (1) inhibition the telomere maintenance by inhibiting the telomerase activity; (2) activating the residual telomerase enzyme or inducing telomerase expression. Whilst the former approach could abolish the limitless replicative potential of malignant cells, the activation of telomerase might be utilized for treating degenerative diseases. Here, we review the current status of telomerase therapeutics, summarizing the activities of those pharmacological agents which either inhibit or activate the enzyme. We also discuss the future opportunities and challenges of research on pharmacological intervention of telomerase activity.
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Affiliation(s)
- I Tárkányi
- 3rd Department of Internal Medicine, University of Debrecen, 22 Moricz Zsigmond Krt., Debrecen 4004, Hungary
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