1
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99mTc-hexoprenaline and 131I-dapoxetine: preparation, in silico modeling and biological evaluation as promising lung scintigraphy radiopharmaceuticals. J Radioanal Nucl Chem 2017. [DOI: 10.1007/s10967-017-5500-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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2
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Thulasiram B, Devi CS, Kumar YP, Aerva RR, Satyanarayana S, Nagababu P. Correlation Between Molecular Modelling and Spectroscopic Techniques in Investigation With DNA Binding Interaction of Ruthenium(II) Complexes. J Fluoresc 2016; 27:587-594. [PMID: 27924438 DOI: 10.1007/s10895-016-1986-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Accepted: 11/09/2016] [Indexed: 01/16/2023]
Abstract
The DNA binding studies of rutheniumu(II) polypyridyl complexes {[Ru(phen)2Mipc]2+, [Ru(bpy)2Mipc]2+, [Ru(dmb)2Mipc]2+, [Ru(phen)2BrIPC]2+, [Ru(bpy)2BrIPC]2+, [Ru(dmb)2BrIPC]2+, [Ru(phen)2PIP-Cl]2+, [Ru(bpy)2PIP-Cl]2+, [Ru(dmb)2PIP-Cl]2+, [Ru(phen)2IPPBA]2+, [Ru(bpy)2IPPBA]2+, [Ru(dmb)2IPPBA]2+} with DNA investigated by electronic absorption titration, emission and molecular modelling studies to identify the binding interactions. All these complexes are showing good binding constant values ~104 to 105. The intercalative ligands makes the binding of the ruthenium(II) complex with DNA as intercalation mode. The ancillary ligands 1,10-phenanthroline (phen), 4,4'-Dimethyl-2,2'-dipyridyl (dmb) and 2,2'-dipyridine (bpy) having been discovered found to be involved in bond formation with the phosphate backbone of nucleotide base pairs in ruthenium(II) complex-DNA docked complex. The molecular docking results are good agreement with experimental results. The molecular modelling technic should help to extend knowledge about the nature (or) mode of binding of these ruthenium(II) complexes with (calf thymus) CT-DNA.
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Affiliation(s)
- B Thulasiram
- Inorganic & Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad, 500007, Telangana State, India
| | - C Shobha Devi
- Department of Chemistry, RGUKT, Basar, Telangana State, India
| | - Yata Praveen Kumar
- Department of Chemistry, Osmania University, Tarnaka, Hyderabad, Telangana State, India
| | - Rajeshwar Rao Aerva
- Department of Chemical Engineering, Eritrea Institute of Technology, Asmara, Eritrea
| | - S Satyanarayana
- Department of Chemistry, Osmania University, Tarnaka, Hyderabad, Telangana State, India
| | - Penumaka Nagababu
- Inorganic & Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad, 500007, Telangana State, India.
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Kalel R, Mora AK, Ghosh R, Dhavale DD, Palit DK, Nath S. Interaction of a Julolidine-Based Neutral Ultrafast Molecular Rotor with Natural DNA: Spectroscopic and Molecular Docking Studies. J Phys Chem B 2016; 120:9843-53. [DOI: 10.1021/acs.jpcb.6b04811] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rahul Kalel
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
- Department
of Chemistry, Savitribai Phule Pune University, Pune 411007, India
| | - Aruna K. Mora
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Rajib Ghosh
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Dilip D. Dhavale
- Department
of Chemistry, Savitribai Phule Pune University, Pune 411007, India
| | - Dipak K. Palit
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Sukhendu Nath
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
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Deligkaris C, Ascone AT, Sweeney KJ, Greene AJQ. Validation of a computational docking methodology to identify the non-covalent binding site of ligands to DNA. MOLECULAR BIOSYSTEMS 2015; 10:2106-25. [PMID: 24853173 DOI: 10.1039/c4mb00239c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Despite the biomedical consequences of carcinogen-DNA interactions and the potential of DNA as a drug target in medicinal chemistry, only a small number of studies have validated or used docking methods for the prediction of the physical binding of small molecules to DNA. Knowledge of the DNA-physically-bound ligand geometry can lead to the elucidation of the molecular-level mechanism of drugs as well as predicting the subsequent chemical interactions that lead to DNA damage from carcinogens. We sought to validate AutoDock 4.2, a docking method that includes a physics-based free energy function and a Lamarckian Genetic Algorithm, for the prediction of ligand geometries upon physical binding to DNA. We performed simulations by systematically changing the length of the search process for a comprehensive set of 32 ligand-DNA molecular systems with different physico-chemical properties, and we used a free-energy-based convergence criterion to terminate our simulations. For 11 out of 28 molecular systems for which convergence was achieved, the lowest binding free energy geometries were within 2 Å of the experimentally determined geometry. Considering all predicted sites with free energy changes within 20% of the lowest binding free energy site, we found a site within 2 Å of the experimentally determined geometry for 24 out of the 28 systems. However, the predicted hydrogen bonding interactions were different for most molecular systems compared to the same interactions in the experimentally determined geometry. We discuss reasons for the successes and failures, implications, and the importance of ensuring an adequate search in docking calculations. Overall, we concluded that AutoDock 4.2 can be used to predict the non-covalent binding geometry of a small molecule to DNA with some limitations.
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Shahabadi N, Falsafi M. Experimental and molecular docking studies on DNA binding interaction of adefovir dipivoxil: advances toward treatment of hepatitis B virus infections. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 125:154-159. [PMID: 24548808 DOI: 10.1016/j.saa.2014.01.066] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 12/25/2013] [Accepted: 01/08/2014] [Indexed: 06/03/2023]
Abstract
The toxic interaction of adefovir dipivoxil with calf thymus DNA (CT-DNA) was investigated in vitro under simulated physiological conditions by multi-spectroscopic techniques and molecular modeling study. The fluorescence spectroscopy and UV absorption spectroscopy indicated drug interacted with CT-DNA in a groove binding mode. The binding constant of UV-visible and the number of binding sites were 3.33±0.2×10(4) L mol(-1)and 0.99, respectively. The fluorimetric studies showed that the reaction between the drug and CT-DNA is exothermic (ΔH=34.4 kJ mol(-1); ΔS=184.32 J mol(-1) K(-1)). Circular dichroism spectroscopy (CD) was employed to measure the conformational change of CT-DNA in the presence of adefovir dipivoxil, which verified the groove binding mode. Furthermore, the drug induces detectable changes in its viscosity. The molecular modeling results illustrated that adefovir strongly binds to groove of DNA by relative binding energy of docked structure -16.83 kJ mol(-1). This combination of multiple spectroscopic techniques and molecular modeling methods can be widely used in the investigation on the toxic interaction of small molecular pollutants and drugs with bio macromolecules, which contributes to clarify the molecular mechanism of toxicity or side effect in vivo.
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Affiliation(s)
- Nahid Shahabadi
- Department of Chemistry, Faculty of Science, Razi University, Kermanshah, Iran.
| | - Monireh Falsafi
- Department of Chemistry, Faculty of Science, Razi University, Kermanshah, Iran
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Affiliation(s)
- Yocheved Gilad
- Department of Chemistry, Bar Ilan University, Ramat-Gan 52900, Israel
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7
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Yao JL, Gao X, Sun W, Shi S, Yao TM. [Ru(bpy)2dppz-idzo]2+: a colorimetric molecular “light switch” and powerful stabilizer for G-quadruplex DNA. Dalton Trans 2013; 42:5661-72. [DOI: 10.1039/c3dt32640c] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Cheng TT, Yao JL, Gao X, Sun W, Shi S, Yao TM. A new fluorescence “switch on” assay for heparin detection by using a functional ruthenium polypyridyl complex. Analyst 2013; 138:3483-9. [DOI: 10.1039/c3an00242j] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Balagurumoorthy P, Xu X, Wang K, Adelstein SJ, Kassis AI. Effect of distance between decaying (125)I and DNA on Auger-electron induced double-strand break yield. Int J Radiat Biol 2012; 88:998-1008. [PMID: 22732063 DOI: 10.3109/09553002.2012.706360] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To determine the possible effects of (125)I-to-DNA distance on the magnitude and mechanism of Auger-electron induced-double-strand break (DSB) production. MATERIALS AND METHODS We have synthesized a series of (125)I-labeled Hoechst (H) derivatives ((125)IE-H, (125)IB-H, (125)I-C(8)-H and (125)I-C(12)-H). While all four molecules share a common DNA minor groove binding bis-benzimidazole motif, they are designed to position (125)I at varying distances from the DNA helix. Each Hoechst derivative was incubated at 4°C in phosphate buffered saline (PBS) together with supercoiled (SC) (3)H-pUC19 plasmid DNA (ratio 3:1) ± the •OH scavenger dimethyl sulfoxide (DMSO) (0.2 M). Aliquots were analyzed on agarose gels over time and DSB yields per decay of (125)I atom were determined. Docking of the iodinated compounds on a DNA molecule was carried out to determine the distance between the iodine atom and the central axis of DNA. RESULTS In the absence of DMSO, the results show that the DSB yields decrease monotonically as the (125)I atom is distanced - by 10.5 Å to 13.9 Å - from the DNA helix ((125)IEH: 0.52 ± 0.01; (125)IB-H: 0.24 ± 0.03; (125)I-C(8)-H: 0.18 ± 0.02; (125)I-C(12)-H: 0.10 ± 0.00). In the presence of DMSO, DSB yields for (125)IEH (0.49 ± 0.02) and (125)IB-H (0.26 ± 0.04) remain largely unchanged indicating that DSB are entirely produced by direct effects. Strikingly, (125)I-C(8)-H or (125)I-C(12)-H, did not produce detectable DSB in the presence of DMSO under similar conditions suggesting when (125)I atom is positioned > 12 Å from the DNA, DSB are entirely produced by indirect effects. CONCLUSION These results suggest that at a critical distance between the (125)I atom and the DNA helix, DSB production switches from an 'all' direct to an 'all' indirect mechanism, the latter situation being comparable to the decay of (125)I free in solution. These experimental findings were correlated with theoretical expectations based on microdosimetry.
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Ricci CG, Netz PA. Docking studies on DNA-ligand interactions: building and application of a protocol to identify the binding mode. J Chem Inf Model 2009; 49:1925-35. [PMID: 19655805 DOI: 10.1021/ci9001537] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Despite DNA being an important target for several drugs, most of the docking programs are validated only for proteins and their ligands. In this paper, we used AutoDock 4.0 to perform self-dockings and cross dockings between two DNA ligands (a minor groove binder and an intercalator) and four distinct receptors: 1) crystallographic DNA without intercalation gap; 2) crystallographic DNA with intercalation gap; 3) canonical B-DNA; and 4) modified B-DNA with intercalation gap. Besides being efficient in self-dockings, AutoDock is capable of correctly identifying two of the main DNA binding modes with the condition that the target possesses an artificial intercalation gap. Therefore, we suggest a default protocol to identify DNA binding modes which uses a modified canonical DNA (with gap) as receptor. This protocol was applied to dock two different Troger bases to DNA and the predicted binding modes agree with those suggested, yet not established, by experimental data. We also applied the protocol to dock aflatoxin B(1) exo-8,9-epoxide, and the results are in complete agreement with experimental data from the literature. We propose that this approach can be used to investigate other ligands whose binding mode to DNA remains unknown, yielding a suitable starting point for further theoretical studies such as molecular dynamics simulations.
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Affiliation(s)
- Clarisse G Ricci
- Instituto de Quimica, Universidade Federal do Rio Grande do Sul, av Bento Goncalves 9500, 91501-970, Porto Alegre, Brazil
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11
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Singh A, Yang Y, Adelstein SJ, Kassis AI. Synthesis and application of molecular probe for detection of hydroxyl radicals produced by Na(125)I and gamma-rays in aqueous solution. Int J Radiat Biol 2009; 84:1001-10. [PMID: 19061124 DOI: 10.1080/09553000802552143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE To synthesize N-(3-(3-aminopropylamino)propyl)-2-oxo-2H-chromene-3-carboxamide (7), a novel DNA-binding, coumarin-based, fluorescent hydroxylradical ((*)OH) indicator and to assess its quantum efficiency compared with that of coumarin-3-carboxylic acid (1) and N1,N12-bis[2-oxo-2H-chromene-3-carbonyl]- 1,12-diamine-4,9-diazadodecane (9). MATERIALS AND METHODS Using computer-generated molecular modeling, 7 and 9 and their respective 7-hydroxylated derivatives 8 and 10 were docked onto DNA dodecamer d(CGCGAATTCGCG)2, the ligand-DNA complexes were energy minimized, and binding free energies and inhibition constants were calculated. Compound 7 was judged an appropriate target molecule and was synthesized. Compounds 1, 7, and 9 were incubated with Na(125)I or irradiated with (137)Cs gamma-rays, and the influence of pH, dose, type of radiation, and the concentration of indicator on fluorescence yield were determined. RESULTS Non-fluorescent 7 and 9 are converted to fluorescent, 7-hydroxylated derivatives 8 and 10 after interaction with (*)OH in aqueous solution. For 1, 7, and 9, hydroxylation yield increases linearly with both Na(125)I dose (0-700 x 10(6) decays) and (137)Cs dose (0-11.0 Gy). Fluorescence induction is significantly reduced at acidic pH and the fluorescent quantum yield of 8 is approximately 3 times that of 2 or 10 at pH 7.0. With Na(125)I incubation and gamma-ray irradiation, the fluorescence signal of 7 increases linearly with concentration and saturates at approximately 50 microM. CONCLUSION Compound 7 quantifies lower concentrations of (*)OH than do 1 and 9. This detector is therefore likely to be a good reporter of (*)OH produced within a few nanometers of DNA.
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Affiliation(s)
- Amarjit Singh
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
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Ghosh S, Usharani D, De S, Jemmis ED, Bhattacharya S. Photophysical and duplex-DNA-binding properties of distamycin dimers based on 4,4'- and 2,2'-dialkoxyazobenzenes as the core. Chem Asian J 2009; 3:1949-61. [PMID: 18810740 DOI: 10.1002/asia.200800151] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Distamycin-based tetrapeptide (1) was covalently tethered to both ends of the central dihydroxyazobenzene moiety at either the 2,2' or 4,4' positions. This afforded two isomeric, distamycin-azobenzene-distamycin systems, 2 (para) and 3 (ortho), both of them being photoisomerizable. Illumination of these conjugates in solution at approximately 360 nm induced photoisomerization and the time course of the process was followed by UV/Vis and (1)H NMR spectroscopy. The kinetics of the thermal reversion at various temperatures of cis to trans isomers of the conjugates obtained after photoillumination were also examined. This afforded the respective thermal-activation parameters. Both the molecular architecture and the location of the substituent around the core azobenzene determined the rate and activation-energy barrier for the cis-to-trans back-isomerization of these conjugates in solution. Duplex-DNA binding of the conjugates and the changes in DNA-binding efficiency upon photoisomerization was also examined by CD spectroscopy, thermal denaturation studies, and a Hoechst displacement assay. The conjugate 2 showed higher DNA-binding affinity and a greater change in the DNA-binding efficiency upon photoisomerization compared with its 2,2'-disubstituted counterpart. The experimental findings were substantiated by using molecular-docking studies involving each conjugate with a model duplex d[(GC(AT)(10)CG)](2) DNA molecule.
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Affiliation(s)
- Sumana Ghosh
- Department of Organic Chemistry, Indian Institute of Science, Bangalore 560 012, India
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Ghosh S, Usharani D, Paul A, De S, Jemmis ED, Bhattacharya S. Design, Synthesis, and DNA Binding Properties of Photoisomerizable Azobenzene−Distamycin Conjugates: An Experimental and Computational Study. Bioconjug Chem 2008; 19:2332-45. [DOI: 10.1021/bc800130u] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sumana Ghosh
- Department of Organic Chemistry and Department of Inorganic and Physical Chemistry, Indian Institute of Science, and Chemical Biology Unit, Jawaharlal Nehru Centre of Advanced Scientific Research, Bangalore 560 012, India
| | - Dandamudi Usharani
- Department of Organic Chemistry and Department of Inorganic and Physical Chemistry, Indian Institute of Science, and Chemical Biology Unit, Jawaharlal Nehru Centre of Advanced Scientific Research, Bangalore 560 012, India
| | - Ananya Paul
- Department of Organic Chemistry and Department of Inorganic and Physical Chemistry, Indian Institute of Science, and Chemical Biology Unit, Jawaharlal Nehru Centre of Advanced Scientific Research, Bangalore 560 012, India
| | - Susmita De
- Department of Organic Chemistry and Department of Inorganic and Physical Chemistry, Indian Institute of Science, and Chemical Biology Unit, Jawaharlal Nehru Centre of Advanced Scientific Research, Bangalore 560 012, India
| | - Eluvathingal D. Jemmis
- Department of Organic Chemistry and Department of Inorganic and Physical Chemistry, Indian Institute of Science, and Chemical Biology Unit, Jawaharlal Nehru Centre of Advanced Scientific Research, Bangalore 560 012, India
| | - Santanu Bhattacharya
- Department of Organic Chemistry and Department of Inorganic and Physical Chemistry, Indian Institute of Science, and Chemical Biology Unit, Jawaharlal Nehru Centre of Advanced Scientific Research, Bangalore 560 012, India
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El-Ayaan U, Abdel-Aziz AAM, Al-Shihry S. Solvatochromism, DNA binding, antitumor activity and molecular modeling study of mixed-ligand copper(II) complexes containing the bulky ligand: Bis[N-(p-tolyl)imino]acenaphthene. Eur J Med Chem 2007; 42:1325-33. [PMID: 17428583 DOI: 10.1016/j.ejmech.2007.02.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2006] [Revised: 01/26/2007] [Accepted: 02/12/2007] [Indexed: 11/19/2022]
Abstract
Four mixed-ligand copper(II) complexes of the nitrogen ligand bis[N-(p-tolyl)imino]acenaphthene 1 (p-Tol-BIAN). These complexes, namely [Cu(p-Tol-BIAN)2](ClO4)2 2, [Cu(p-Tol-BIAN)(acac)](ClO4) 3, [Cu(p-Tol-BIAN)Cl2] 4 and [Cu(p-Tol-BIAN)(AcOH)(2)](ClO4)2 5, were prepared and characterized. Solvatochromism of the novel copper complexes in various solvents has been studied. Molecular mechanics (MM+) and molecular dynamic simulations have been performed to learn more about the solvatochromic behaviour and the DNA binding affinity of these complexes.
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Affiliation(s)
- Usama El-Ayaan
- Department of Chemistry, Faculty of Science, Mansoura University, Mansoura 35516, Egypt.
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Singh A, Chen K, Adelstein SJ, Kassis AI. Synthesis of Coumarin–Polyamine-Based Molecular Probe for the Detection of Hydroxyl Radicals Generated by Gamma Radiation. Radiat Res 2007; 168:233-42. [PMID: 17638412 DOI: 10.1667/rr0948.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Accepted: 03/15/2007] [Indexed: 11/03/2022]
Abstract
To develop a molecular probe for detection of hydroxyl radicals in the vicinity of DNA, the coumarin-polyamine complexes, N(1),N(12)-bis[2-oxo-2H-chromene-3-carbonyl]-1,12-diamine-4,9-diazadodecane (5) and tris[2-(2-oxo-2H-chromene-3-carboxamido)ethyl]amine (7), and their hydroxylated derivatives, N(1),N(12)-bis[7-hydroxy-2-oxo-2H-chromene-3-carbonyl]-1,12-diamine-4,9-diazadodecane (6) and tris[2-(7-hydroxy-2-oxo-2H-chromene-3-carboxamido)ethyl]amine (8), have been synthesized. Using computer-generated molecular modeling, the derivatives have been docked onto DNA dodecamer d(CGCGAATTCGCG)(2), the ligand-DNA complexes have been minimized, and the free binding energies (DeltaG(binding)) and inhibition constants (K(i)) have been calculated. Compound 7 is not water-soluble at the concentrations required for the project. When aqueous solutions of 5 are irradiated with gamma rays, the relationship between induced fluorescence and dose is linear in the range of 0 to 10 Gy. The fluorescence emission spectrum of irradiated 5 is similar to that of its dihydroxy derivative 6, indicating conversion of 5 to 6, and induction of fluorescence records formation of hydroxyl radicals in aqueous solution. The dicoumarin-polyamine 5, a novel compound for the detection of hydroxyl radicals close to DNA, is a sensitive and quantitative probe with potential for applications in biological systems.
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Affiliation(s)
- Amarjit Singh
- Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
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Yasui LS, Chen K, Wang K, Jones TP, Caldwell J, Guse D, Kassis AI. Using Hoechst 33342 to target radioactivity to the cell nucleus. Radiat Res 2007; 167:167-75. [PMID: 17390724 DOI: 10.1667/rr0584.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We have explored the use of Hoechst 33342 (H33342) to carry radioactivity to the cell nucleus. H33342 enters cells and targets DNA at adenine-thymine-rich regions of the minor groove. Considerable membrane blebbing and ruffling occur in CHO cells within minutes after its addition to the culture medium in micromolar quantities. Blue vesicles are apparent in the cell cytoplasm, and by 30 min the nuclei are stained dark blue. Upon its binding to DNA, a visible emission shift of the dye can be observed with fluorescence microscopy. We have radioiodinated (125I) H33342 and specifically irradiated nuclear DNA by incubating CHO cells with 125I-H33342 at 37 degrees C and accumulating 125I decays at -90 degrees C. At various times, the cells are thawed and assayed for survival (clonogenicity) and DSB (gamma-H2AX) formation. 125I-H33342 decay leads to a monoexponential decrease in cell survival with a D0 of 122 125I decays per cell and a linear increase in DNA DSB induction (equivalent to 15 gamma-H2AX foci/cell). Cell death is not modified by the radioprotective effects of H33342 because we use considerably lower concentrations than those that provide a slight protection against gamma radiation. We conclude that cell killing by 125I-H33342 and the induction of gamma-H2AX foci are highly correlated.
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Affiliation(s)
- Linda S Yasui
- Northern Illinois University, Department of Biological Sciences, DeKalb, Illinois 60115, USA.
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Abdel-Aziz AAM. Novel and versatile methodology for synthesis of cyclic imides and evaluation of their cytotoxic, DNA binding, apoptotic inducing activities and molecular modeling study. Eur J Med Chem 2006; 42:614-26. [PMID: 17234303 DOI: 10.1016/j.ejmech.2006.12.003] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Revised: 11/25/2006] [Accepted: 12/01/2006] [Indexed: 12/31/2022]
Abstract
Versatile method has been developed for synthesis of N-substituted imides. Thus, acid anhydrides, imides and dicarboxylic acids were successfully subjected to dehydrative cyclization with substituted amines using DPPOx and Et(3)N to afford N-substituted imides under mild conditions. The DNA binding and apoptosis induction were investigated with regard to their potential utility as cytotoxic agents. Molecular modeling methods are used to study the cytotoxic activity of the active compounds by means of molecular and quantum mechanics.
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Affiliation(s)
- Alaa A-M Abdel-Aziz
- Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.
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Balagurumoorthy P, Chen K, Bash RC, Adelstein SJ, Kassis AI. Mechanisms Underlying Production of Double-Strand Breaks in Plasmid DNA after Decay of125I-Hoechst. Radiat Res 2006; 166:333-44. [PMID: 16881734 DOI: 10.1667/rr3591.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Previously, the kinetics of strand break production by (125)I-labeled m-iodo-p-ethoxyHoechst 33342 ((125)IEH) in supercoiled (SC) plasmid DNA had demonstrated that approximately 1 DSB is produced per (125)I decay both in the presence and absence of the hydroxyl radical scavenger DMSO. In these experiments, an (125)IEH:DNA molar ratio of 42:1 was used. We now hypothesize that this DSB yield (but not the SSB yield) may be an overestimate due to subsequent decays occurring in any of the 41 (125)IEH molecules still bound to nicked (N) DNA. To test our hypothesis, (125)IEH was incubated with SC pUC19 plasmids ((125)IEH:DNA ratio of approximately 3:1) and the SSB and DSB yields were quantified after the decay of (125)I. As predicted, the number of DSBs produced per (125)I decay is one-half that reported previously ( approximately 0.5 compared to approximately 1, +/- DMSO) whereas the number of SSBs ( approximately 3/(125)I decay) is similar to that obtained previously ( approximately 90% are generated by OH radicals). Direct visualization by atomic force microscopy confirms formation of L and N DNA after (125)IEH decays in SC DNA and supports the strand break yields reported. These findings indicate that although SSB production is independent of the number of (125)IEH bound to DNA, the DSB yield can be augmented erroneously by (125)I decays occurring in N DNA. Further analysis indicates that 17% of SSBs and 100% of DSBs take place within the plasmid molecule in which an (125)IEH molecule decays, whereas 83% of SSBs are formed in neighboring plasmid DNA molecules.
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