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Jin M, Li J, Chen Y, Zhao J, Zhang J, Zhang Z, Du P, Zhang L, Lu X. Near-Infrared Small Molecule as a Specific Fluorescent Probe for Ultrasensitive Recognition of Antiparallel Human Telomere G-Quadruplexes. ACS APPLIED MATERIALS & INTERFACES 2021; 13:32743-32752. [PMID: 34228441 DOI: 10.1021/acsami.1c07101] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In the past 10 years, many fluorescent probes have been developed to recognize G-quadruplexes (G4s) since G4s play an important role in biological systems. However, the selectivity and sensitivity of existing probes for G4s limit their further applications. Herein, we design and synthesize a new probe (TOVJ) by introducing 9-vinyljulolidine into TO. The new probe exhibits almost no fluorescence in an aqueous solution. Upon interacting with G4s, especially the antiparallel G4s, the fluorescence intensity was greatly enhanced (maximum 2742-fold) with a large Stokes shift of 198 nm and the maximum emission peak at 694 nm (near-infrared region). TOVJ showed high sensitivity and selectivity to G4s over other DNA topologies (ssDNA/dsDNA), especially to antiparallel G4s. For antiparallel human telomere G4 detection, the limits of detection of Hum24 and 22AG Na+ were as low as 164 and 231 pM, respectively. This indicates that TOVJ is a highly sensitive fluorescence sensor that can be effectively used for antiparallel human telomere G4 detection. The result of live-cell imaging showed that TOVJ could enter live cells and locate in the mitochondria.
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Affiliation(s)
- Ming Jin
- Tianjin Key Laboratory of Molecular Optoelectronic, Department of Chemistry, Tianjin University, Tianjin 300072, People's Republic of China
| | - Jing Li
- Tianjin Key Laboratory of Molecular Optoelectronic, Department of Chemistry, Tianjin University, Tianjin 300072, People's Republic of China
| | - Yang Chen
- Tianjin Key Laboratory of Molecular Optoelectronic, Department of Chemistry, Tianjin University, Tianjin 300072, People's Republic of China
| | - Jie Zhao
- Tianjin Key Laboratory of Molecular Optoelectronic, Department of Chemistry, Tianjin University, Tianjin 300072, People's Republic of China
| | - Jiahui Zhang
- Tianjin Key Laboratory of Molecular Optoelectronic, Department of Chemistry, Tianjin University, Tianjin 300072, People's Republic of China
| | - Zhen Zhang
- Tianjin Key Laboratory of Molecular Optoelectronic, Department of Chemistry, Tianjin University, Tianjin 300072, People's Republic of China
| | - Peiyao Du
- Tianjin Key Laboratory of Molecular Optoelectronic, Department of Chemistry, Tianjin University, Tianjin 300072, People's Republic of China
| | - Libing Zhang
- Tianjin Key Laboratory of Molecular Optoelectronic, Department of Chemistry, Tianjin University, Tianjin 300072, People's Republic of China
| | - Xiaoquan Lu
- Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, People's Republic of China
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2
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Jackson MR, Bavelaar BM, Waghorn PA, Gill MR, El-Sagheer AH, Brown T, Tarsounas M, Vallis KA. Radiolabeled Oligonucleotides Targeting the RNA Subunit of Telomerase Inhibit Telomerase and Induce DNA Damage in Telomerase-Positive Cancer Cells. Cancer Res 2019; 79:4627-4637. [PMID: 31311806 PMCID: PMC7611324 DOI: 10.1158/0008-5472.can-18-3594] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 05/01/2019] [Accepted: 07/12/2019] [Indexed: 12/17/2022]
Abstract
Telomerase is expressed in the majority (>85%) of tumors, but has restricted expression in normal tissues. Long-term telomerase inhibition in malignant cells results in progressive telomere shortening and reduction in cell proliferation. Here we report the synthesis and characterization of radiolabeled oligonucleotides that target the RNA subunit of telomerase, hTR, simultaneously inhibiting enzymatic activity and delivering radiation intracellularly. Oligonucleotides complementary (Match) and noncomplementary (Scramble or Mismatch) to hTR were conjugated to diethylenetriaminepentaacetic dianhydride (DTPA), allowing radiolabeling with the Auger electron-emitting radionuclide indium-111 (111In). Match oligonucleotides inhibited telomerase activity with high potency, which was not observed with Scramble or Mismatch oligonucleotides. DTPA-conjugation and 111In-labeling did not change telomerase inhibition. In telomerase-positive cancer cells, unlabeled Match oligonucleotides had no effect on survival, however, 111In-labeled Match oligonucleotides significantly reduced clonogenic survival and upregulated the DNA damage marker γH2AX. Minimal radiotoxicity and DNA damage was observed in telomerase-negative cells exposed to 111In-Match oligonucleotides. Match oligonucleotides localized in close proximity to nuclear Cajal bodies in telomerase-positive cells. In comparison with Match oligonucleotides, 111In-Scramble or 111In-Mismatch oligonucleotides demonstrated reduced retention and negligible impact on cell survival. This study indicates the therapeutic activity of radiolabeled oligonucleotides that specifically target hTR through potent telomerase inhibition and DNA damage induction in telomerase-expressing cancer cells and paves the way for the development of novel oligonucleotide radiotherapeutics targeting telomerase-positive cancers. SIGNIFICANCE: These findings present a novel radiolabeled oligonucleotide for targeting telomerase-positive cancer cells that exhibits dual activity by simultaneously inhibiting telomerase and promoting radiation-induced genomic DNA damage.
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Affiliation(s)
- Mark R Jackson
- Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Bas M Bavelaar
- Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Philip A Waghorn
- Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Martin R Gill
- Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Afaf H El-Sagheer
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Tom Brown
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Madalena Tarsounas
- Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Katherine A Vallis
- Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom.
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3
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Abstract
Peptide nucleic acids (PNA) are widely used DNA mimics that bind sequence specifically to single- and double-stranded nucleic acids. Hence they are of interest in the design of gene-targeted radiotherapeutics that could deliver radiodamage to designated DNA and/or RNA sites. Here I describe a procedure for incorporation of gamma-emitting radionuclide 111In into PNA oligomers. Diethylenetriaminepentaacetic acid (DTPA) was conjugated to a lysine-containing mixed-base PNA. 111In-labeled PNAs were obtained by chelation of PNA-DTPA conjugates with 111In3+ in an acidic aqueous solution.
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Affiliation(s)
- Igor G Panyutin
- Department of Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA.
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4
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Jin M, Liu X, Zhang X, Wang L, Bing T, Zhang N, Zhang Y, Shangguan D. Thiazole Orange-Modified Carbon Dots for Ratiometric Fluorescence Detection of G-Quadruplex and Double-Stranded DNA. ACS APPLIED MATERIALS & INTERFACES 2018; 10:25166-25173. [PMID: 29979027 DOI: 10.1021/acsami.8b07869] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
A new carbon dot (CD)-based nanoprobe for the ratiometric fluorescence detection of DNA was constructed in this work. Thiazole orange (TO), a specific organic small molecular probe toward DNA, is covalently linked to the surface of CDs, acting as the recognition element and the fluorescence response unit. In the absence of DNA, the nanoprobe only emitted the blue fluorescence of CDs, whereas TO was almost nonfluorescent. Upon addition of DNA, a turn-on emission at 530 nm appeared and gradually enhanced along with the increasing of the target DNA, whereas the fluorescence of CDs was unchanged, which realized the ratiometric detection of the target DNA. The CD-TO nanoprobe showed good selectivity to parallel G-quadruplex (G4) and double-stranded (ds) DNA over antiparallel G4 and single-stranded DNA. Moreover, the ratiometric fluorescence nanoprobe exhibited high sensitivity for ssab (a dsDNA) and c-myc (a parallel G4) with a low detection limit of 0.90 and 3.31 nM, respectively. Additionally, the G4/hemin peroxidase activity inhibition experiment demonstrated that CD-TO bound to the G4s through the end-stacking mode.
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Affiliation(s)
- Ming Jin
- College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , China
| | - Xiangjun Liu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Xin Zhang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Linlin Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Tao Bing
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Nan Zhang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
| | - Yun Zhang
- College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , China
| | - Dihua Shangguan
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
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5
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Vultos F, Fernandes C, Mendes F, Marques F, Correia JDG, Santos I, Gano L. A Multifunctional Radiotheranostic Agent for Dual Targeting of Breast Cancer Cells. ChemMedChem 2017. [PMID: 28628723 DOI: 10.1002/cmdc.201700287] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A straightforward synthetic route for a new multifunctional 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) derivative is described. To demonstrate the versatility of this pro-chelator for the preparation of radiolabeled hybrid compounds containing two different biological targeting moieties, an antitumor agent (e.g., a DNA-intercalating agent) and an estrogen receptor (ER) ligand (e.g., LXXLL-based peptide) were regiospecifically conjugated to the DOTA derivative. The bifunctional probe was radiolabeled with the auger electron emitter indium-111, and the resulting radioconjugate was demonstrated to induce DNA damage in vitro, which, along with the nuclear internalization exhibited in breast cancer cells, might enhance its therapeutic activity. This favorable in vitro performance suggests that these hybrid compounds could be attractive probes for theranostic applications.
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Affiliation(s)
- Filipe Vultos
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139.7, 2695-066, Bobadela, LRS, Portugal
| | - Célia Fernandes
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139.7, 2695-066, Bobadela, LRS, Portugal
| | - Filipa Mendes
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139.7, 2695-066, Bobadela, LRS, Portugal
| | - Fernanda Marques
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139.7, 2695-066, Bobadela, LRS, Portugal
| | - João D G Correia
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139.7, 2695-066, Bobadela, LRS, Portugal
| | - Isabel Santos
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139.7, 2695-066, Bobadela, LRS, Portugal
| | - Lurdes Gano
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139.7, 2695-066, Bobadela, LRS, Portugal
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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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Stephan H, Foerster C, Gasser G. Synthesis, characterization, and evaluation of radiometal-containing peptide nucleic acids. Methods Mol Biol 2014; 1050:37-54. [PMID: 24297349 DOI: 10.1007/978-1-62703-553-8_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Peptide nucleic acids (PNAs) have very attractive properties for applications in nuclear medicine. Because PNAs have high selectivity for DNA/RNA recognition, resistance to nuclease/protease degradation, and high thermal and radiolytic stabilities, PNA bioconjugates could transform the areas of diagnostic and therapeutic nuclear medicine. In this book chapter, we report on the current developments towards the preparation of radiometal-containing PNA constructs and summarize the protocols for labeling these probes with (99m)Tc, (111)In, (64)Cu, (90)Y, and (177)Lu.
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Affiliation(s)
- Holger Stephan
- Institute of Radiopharmaceutical Cancer Research, Helmholtz- Zentrum Dresden-Rossendorf, Dresden, Germany
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8
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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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9
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Gasser G, Sosniak AM, Metzler-Nolte N. Metal-containing peptide nucleic acid conjugates. Dalton Trans 2011; 40:7061-76. [PMID: 21541385 DOI: 10.1039/c0dt01706j] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Peptide Nucleic Acids (PNAs) are non-natural DNA/RNA analogues with favourable physico-chemical properties and promising applications. Discovered nearly 20 years ago, PNAs have recently re-gained quite a lot of attention. In this Perspective article, we discuss the latest advances on the preparation and utilisation of PNA monomers and oligomers containing metal complexes. These metal- conjugates have found applications in various research fields such as in the sequence-specific detection of nucleic acids, in the hydrolysis of nucleic acids and peptides, as radioactive probes or as modulators of PNA·DNA hybrid stability, and last but not least as probes for molecular and cell biology.
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Affiliation(s)
- Gilles Gasser
- Institute of Inorganic Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.
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Sosniak AM, Gasser G, Metzler-Nolte N. Thermal melting studies of alkyne- and ferrocene-containing PNA bioconjugates. Org Biomol Chem 2009; 7:4992-5000. [PMID: 19907791 DOI: 10.1039/b913964h] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The preparation of new metal-containing Peptide Nucleic Acids (PNAs) is currently a field of research intensively studied for various purposes, e.g. DNA biosensors. The role played by the metal centre, notably on the stability of the PNA.DNA hybrid, is obviously crucial, but has not yet been fully investigated. In this work, UV-Vis spectroscopic measurements of solutions of DNA.PNA hybrids, whose 11/12-mer PNA oligomers contained either one or two alkyne- (1) or ferrocene-containing (2) PNA monomers, were carried out to determine the effect of these monomers on the thermal stability of the hybrids (PNA: H-Gly-X-gggtc-Y-agctt-X-Lys-NH2 with X = 1 or and Y = 1 or 2 or blank position). Supplementary CD spectroscopic measurements were performed to gain insight into the structures of the PNA.DNA duplexes formed. The effect of both modified monomers was found to depend on their actual positions within the PNA sequences. Insertions at the N- or C-termini of a PNA oligomer did not change the melting temperatures (T(m) values of about 72 degrees C) of the DNA.PNA hybrids significantly. Insertion of monomers 1 or 2 in the middle of a PNA sequence induced a substantial decrease in the T(m) of the hybrids (by about 23 degrees C) when bound to the same DNA oligomer. Interestingly, it was found that the type of modification, namely alkyne or ferrocene, did not significantly influence the T(m) values in these cases. However, the thermal stability of hybrids with the DNA oligomers containing one to four additional thymines and the PNA oligomers containing the ferrocene moiety in its middle, varied significantly with the number of thymines added compared to its alkyne analogues (DeltaT(m) up to -13 degrees C). The presence of the ferrocene moiety induced a significant decrease in thermal stability of the hybrids, probably due to its bulkiness. In order to assess the effect of PNA backbone rigidity on the stability of DNA.PNA hybrids, PNA oligomers with an internal amino acid, propargylglycine (Pgl) or the dipeptide glycine-propargylglycine (Gly-Pgl), were synthesised. It was assumed that the orientation of the alkyne moiety in the Pgl-containing PNA sequence is not identical to an alkyne-containing PNA sequence, as a significantly higher T(m) value (DeltaT(m) = +10 degrees C) was measured. It is anticipated that the alkyne moiety in Pgl is not facing the DNA base and therefore does not disturb as much the neighbouring nucleobases and base-stacking of the complementary DNA, in contrast to the alkyne moiety of 1. Interestingly, no significant differences in the thermal stability of the hybrids was observed between Pgl-containing and dipeptide-containing PNA oligomers, although the former contracts the PNA backbone by three atoms.
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Affiliation(s)
- Anna M Sosniak
- Ruhr-University Bochum, Faculty of Chemistry and Biochemistry, Inorganic Chemistry I-Bioinorganic Chemistry, Universitätsstrasse 150, D-44801, Bochum, Germany
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Gaynutdinov TI, Neumann RD, Panyutin IG. Iodine-125 radioprobing of intramolecular quadruplex conformation of human telomeric DNA in the presence of cationic porphyrin TMPyP4. Int J Radiat Biol 2009; 84:984-90. [PMID: 19061122 DOI: 10.1080/09553000802415747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE A repeated, non-coding, DNA sequence d(TTAGGG)(n) is present in the telomeric ends of all human chromosomes. These repeats can adopt multiple inter- and intra-molecular non-B-DNA conformations that may play an important role in biological processes. We applied (125)I -radioprobing to assess the conformation of the human telomeric DNA fragment in a complex with the quadruplex-specific drug - cationic porphyrin TMPyP4. MATERIAL AND METHODS Synthetic DNA oligonucleotides containing the telomeric sequence were labeled with (125)I. The probability of DNA breaks caused by decay of (125)I is inversely related to the distance between the radionuclide and the sugar unit of the DNA backbone; hence, the conformation of the DNA backbone can be deduced from the distribution of breaks. RESULTS The obtained data indicate that the telomeric oligonucleotides predominantly fold into an intramolecular quadruplex conformation in the presence of TMPyP4. We propose a mixed-type (3 + 1) conformation of telomeric quadruplex in a complex with the cationic porphyrin TMPyP4 in solution. Binding of the porphyrin overrides the counterion effect on quadruplex conformation. CONCLUSIONS We have demonstrated that (125)I radioprobing can be successfully applied not only to determine folding in G-quadruplexes, but also to reveal the mode of quadruplex interaction with small ligands.
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Affiliation(s)
- Timur I Gaynutdinov
- Department of Nuclear Medicine, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland, USA.
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12
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Abstract
PURPOSE The extreme radiotoxicity of Auger electrons and their exquisite capacity to irradiate specific molecular sites has prompted scientists to extensively investigate their radiobiological effects. Their efforts have been punctuated by quadrennial international symposia that have focused on biophysical aspects of Auger processes. The latest meeting, the 6th International Symposium on Physical, Molecular, Cellular, and Medical Aspects of Auger Processes, was held 5-6 July 2007 at Harvard Medical School in Boston, Massachusetts, USA. This article provides a review of the research in this field that was published during the years 2004-2007, the period that has elapsed since the previous meeting. CONCLUSION The field has advanced considerably. A glimpse of the potential of this unique form of ionizing radiation to contribute to future progress in a variety of fields of study is proffered.
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Affiliation(s)
- Roger W Howell
- Department of Radiology, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA.
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13
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Costantini DL, Hu M, Reilly RM. Update:Peptide Motifs for Insertion of Radiolabeled Biomolecules into Cells and Routing to the Nucleus for Cancer Imaging or Radiotherapeutic Applications. Cancer Biother Radiopharm 2008; 23:3-24. [DOI: 10.1089/cbr.2007.0430] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Danny L. Costantini
- Leslie Dan Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Meiduo Hu
- Leslie Dan Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Raymond M. Reilly
- Leslie Dan Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
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14
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Buchegger F, Perillo-Adamer F, Dupertuis YM, Delaloye AB. Auger radiation targeted into DNA: a therapy perspective. Eur J Nucl Med Mol Imaging 2006; 33:1352-63. [PMID: 16896663 DOI: 10.1007/s00259-006-0187-2] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 05/29/2006] [Accepted: 06/09/2006] [Indexed: 11/24/2022]
Abstract
BACKGROUND Auger electron emitters that can be targeted into DNA of tumour cells represent an attractive systemic radiation therapy goal. In the situation of DNA-associated decay, the high linear energy transfer (LET) of Auger electrons gives a high relative biological efficacy similar to that of alpha particles. In contrast to alpha radiation, however, Auger radiation is of low toxicity when decaying outside the cell nucleus, as in cytoplasm or outside cells during blood transport. The challenge for such therapies is the requirement to target a high percentage of all cancer cells. An overview of Auger radiation therapy approaches of the past decade shows several research directions and various targeting vehicles. The latter include hormones, peptides, halogenated nucleotides, oligonucleotides and internalising antibodies. DISCUSSION Here, we will discuss the basic principles of Auger electron therapy as compared with vector-guided alpha and beta radiation. We also review some radioprotection issues and briefly present the main advantages and disadvantages of the different targeting modalities that are under investigation.
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Affiliation(s)
- Franz Buchegger
- Service of Nuclear Medicine, University Hospital of Lausanne CHUV, Rue du Bugnon 46, 1011 Lausanne, Switzerland.
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15
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Kersebohm T, Kirin SI, Metzler-Nolte N. Insertion of an internal dipeptide into PNA oligomers: thermal melting studies and further functionalization. Bioorg Med Chem Lett 2006; 16:2964-8. [PMID: 16546386 DOI: 10.1016/j.bmcl.2006.02.071] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 02/23/2006] [Accepted: 02/25/2006] [Indexed: 11/24/2022]
Abstract
The solid phase synthesis of PNA oligomers with the internal dipeptide Gly-Phe is presented and the interaction with complementary DNA investigated. UV absorbance melting experiments with different but complementary DNA sequences show that stable PNA x DNA duplexes are only obtained when there is no DNA base opposite the dipeptide unit. Instead, the dipeptide spacer forms a loop-like structure within the duplex. Further functionalization with N-heterocyclic ligands is described. p-Nitro-phenylalanine is introduced in place of Phe during solid phase synthesis and subsequently reduced to p-amino-phenylalanine. Reaction with activated acids provides the ligand conjugates in high yield and purity. This strategy opens a universal route to a large number of internal substitutions in PNA chemistry.
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Affiliation(s)
- Tim Kersebohm
- Institute of Pharmacy and Molecular Biotechnology, University of Heidelberg, Im Neuenheimer Feld 364, D-69120 Heidelberg, Germany
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16
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Grafström G, Jönsson BA, El Hassan AM, Tennvall J, Strand SE. Rat testis as a radiobiological in vivo model for radionuclides. RADIATION PROTECTION DOSIMETRY 2006; 118:32-42. [PMID: 16046556 DOI: 10.1093/rpd/nci328] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The radiobiological effect of intracellularly localised radionuclides emitting low energy electrons (Auger electrons) has received much attention. Most in vivo studies reported have been performed in the mouse testis. We have investigated the rat testis as an in vivo radiobiological model, with sperm-head survival, testis weight loss and also alteration in the blood plasma hormone levels of FSH and LH as radiobiological endpoints. Validation of the rat testis model was evaluated by using mean absorbed doses of up to 10 Gy from intratesticularly (i.t.) injected (111)In oxine or local X-ray irradiation. Biokinetics of the i.t. injected radionuclide was analysed by scintillation camera imaging and used in the absorbed dose estimation. By the analysis of the autoradiographs, the activity distribution was revealed. Cell fractionation showed (111)In to be mainly associated with the cell nuclei. External irradiations were monitored by thermoluminescence dosimeters. The sperm-head survival was the most sensitive radiobiological parameter correlated to the mean absorbed dose, with a D(37) of 2.3 Gy for (111)In oxine and 1.3 Gy for X rays. The levels of plasma pituitary gonadal hormones FSH and LH were elevated for absorbed doses >7.7 Gy. This investigation shows that the radiobiological model based on the rat testis has several advantages compared with the previously commonly used mouse testis model. The model is appropriate for further investigations of basic phenomena such as radiation geometry, intracellular kinetics and heterogeneity, crucial for an understanding of the biological effect of low-energy electrons.
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Affiliation(s)
- G Grafström
- Departament of Medical Radiation Physics, Lund University, S-221 85 Lund, Sweden.
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Panyutin IG, Neumann RD. The potential for gene-targeted radiation therapy of cancers. Trends Biotechnol 2005; 23:492-6. [PMID: 16125814 DOI: 10.1016/j.tibtech.2005.08.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Revised: 05/23/2005] [Accepted: 08/11/2005] [Indexed: 01/08/2023]
Abstract
Targeted cancer therapy is the mantra now chanted by oncologists of all types. Everyone hopes that the rapid expansion in the knowledge of cancer cell genetics, signaling, regulatory factors and other changes that underlie malignant transformation and metastasis will lead to innovative approaches for the treatment of cancers. To date, successful targeted therapies have been derived from pharmaceutical chemistry - designing chemical compounds intended to disrupt a crucial pathway for malignant cells to survive, grow and metastasize. Radiotherapy also has a goal of more-selective targeting of therapeutic radiation effects to only tumor cells. In this review, we describe our efforts to create a form of gene-targeted radiation therapy by using the unique radiation effects of radionuclides that decay by the Auger process attached to oligonucleotide carrier-molecules that are capable of forming triplex DNA structures with target sequences in the genome of the human cancer cell.
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Affiliation(s)
- Igor G Panyutin
- Nuclear Medicine Department, Clinical Center, NIH, Bethesda, MD 20892-1180, USA.
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Zheng JN, Sun YF, Pei DS, Liu JJ, Sun XQ, Chen JC, Cai WQ, Li W, Cao JY. Anti-Ki-67 peptide nucleic acid affects the proliferation and apoptosis of human renal carcinoma cells in vitro. Life Sci 2005; 76:1873-81. [PMID: 15698864 DOI: 10.1016/j.lfs.2004.10.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2004] [Accepted: 10/26/2004] [Indexed: 11/21/2022]
Abstract
We treated in vitro human renal carcinoma cells (cell line 786-0) with the lipid-delivered peptide nucleic acids (PNAs) against Ki-67 gene. Corresponding control groups were treated with the antisense oligonucleotides (ASOs) of the same nucleobase sequence, and with mismatched PNAs. In cells treated by anti-Ki-67 PNAs, the Ki-67 expression rate, Ki-67 protein level, cell growth and the DNA synthesis-indicative 3H-thymidine incorporation rate were lower than in the ASO-treated groups, and reduced significantly compared to untreated controls, whereas the rate of apoptosis was markedly increased by PNA treatment. We conclude that anti-Ki-67 PNA has more strong (than ASO) and dose-dependent effects on the proliferation and apoptosis of human renal carcinoma cells. Our results indicate that the strategy of using PNA against the Ki-67 gene might be a promising approach in renal carcinoma therapy.
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Affiliation(s)
- Jun-Nian Zheng
- Laboratory of Urology, Affiliated Hospital of Xuzhou Medical College, Xuzhou, 221002, China
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He Y, Neumann RD, Panyutin IG. Intramolecular quadruplex conformation of human telomeric DNA assessed with 125I-radioprobing. Nucleic Acids Res 2004; 32:5359-67. [PMID: 15475390 PMCID: PMC524286 DOI: 10.1093/nar/gkh875] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A repeated non-coding DNA sequence d(TTAGGG)n is present in the telomeric ends of all human chromosomes. These repeats can adopt multiple inter and intramolecular non-B-DNA conformations that may play an important role in biological processes. Two intramolecular structures of the telomeric oligonucleotide dAGGG(TTAGGG)3, antiparallel and parallel, have been solved by NMR and X-ray crystallography. In both structures, the telomeric sequence adopts an intramolecular quadruplex structure that is stabilized by G-4 quartets, but the ways in which the sequence folds into the quadruplex are different. The folds of the human telomeric DNA were described as an anti-parallel basket-type and a parallel propeller-type. We applied 125I-radioprobing to determine the conformation of the telomeric quadruplex in solution, in the presence of either Na+ or K+ ions. The probability of DNA breaks caused by decay of 125I is inversely related to the distance between the radionuclide and the sugar unit of the DNA backbone; hence, the conformation of the DNA backbone can be deduced from the distribution of breaks. The probability of breaks measured in the presence of Na+ and K+ were compared with the distances in basket-type and propeller-type quadruplexes obtained from the NMR and crystal structures. Our radioprobing data demonstrate that the antiparallel conformation was present in solution in the presence of both K+ and Na+. The preferable conformation in the Na+-containing solution was the basket-type antiparallel quadruplex whereas the presence of K+ favored the chair-type antiparallel quadruplex. Thus, we believe that the two antiparallel and the parallel conformations may coexist in solution, and that their relative proportion is determined by the type and concentration of ions.
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Affiliation(s)
- Yujian He
- Department of Nuclear Medicine, Warren G. Magnuson Clinical Center, Building 10, Room 1C401, National Institutes of Health, Bethesda, MD 20892-1180, USA
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