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Buravchenko GI, Shchekotikhin AE. Quinoxaline 1,4-Dioxides: Advances in Chemistry and Chemotherapeutic Drug Development. Pharmaceuticals (Basel) 2023; 16:1174. [PMID: 37631089 PMCID: PMC10459860 DOI: 10.3390/ph16081174] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 08/08/2023] [Accepted: 08/14/2023] [Indexed: 08/27/2023] Open
Abstract
N-Oxides of heterocyclic compounds are the focus of medical chemistry due to their diverse biological properties. The high reactivity and tendency to undergo various rearrangements have piqued the interest of synthetic chemists in heterocycles with N-oxide fragments. Quinoxaline 1,4-dioxides are an example of an important class of heterocyclic N-oxides, whose wide range of biological activity determines the prospects of their practical use in the development of drugs of various pharmaceutical groups. Derivatives from this series have found application in the clinic as antibacterial drugs and are used in agriculture. Quinoxaline 1,4-dioxides present a promising class for the development of new drugs targeting bacterial infections, oncological diseases, malaria, trypanosomiasis, leishmaniasis, and amoebiasis. The review considers the most important methods for the synthesis and key directions in the chemical modification of quinoxaline 1,4-dioxide derivatives, analyzes their biological properties, and evaluates the prospects for the practical application of the most interesting compounds.
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Hamama WS, Waly SM, Said SB, Zoorob HH. Highlights on the chemistry of 2-amino-3-cyano-quinoxaline 1, 4-dioxides and their derivatives. SYNTHETIC COMMUN 2020. [DOI: 10.1080/00397911.2017.1342843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Wafaa S. Hamama
- Chemistry Department, Faculty of Science, Mansoura University, Mansoura City, Egypt
| | - Sara M. Waly
- Chemistry Department, Faculty of Science, Damietta University, Damietta City, Egypt
| | - Samy B. Said
- Chemistry Department, Faculty of Science, Damietta University, Damietta City, Egypt
| | - Hanafi H. Zoorob
- Chemistry Department, Faculty of Science, Mansoura University, Mansoura City, Egypt
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Duran-Giner N, Carlotti B, Clementi C, Elisei F, Encinas S, Miranda MA. Transient absorption spectroscopic studies on 4-nitroquinoline N-oxide: From femtoseconds to microseconds timescale. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 216:265-272. [PMID: 30904634 DOI: 10.1016/j.saa.2019.02.105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 02/22/2019] [Accepted: 02/25/2019] [Indexed: 06/09/2023]
Abstract
The singlet excited state of 4-nitroquinoline N-oxide (1NQNO*) has been characterized by different spectroscopic techniques, combining transient absorption with steady state and time-resolved emission spectroscopy. The energy of 1NQNO* has been established as 255 kJ/mol from the fluorescence spectrum, whereas its lifetime has been found to be 10 ps in the femto-laser flash photolysis (LFP) experiments, where a characteristic S1Sn absorption band with maximum centered at 425 nm is observed. In a first stage, the triplet excited state of NQNO (3NQNO*) has also been characterized by emission spectroscopy in solid matrix, at low temperature. Thus, from the steady-state phosphorescence spectrum the triplet energy has been estimated as 183 kJ/mol, whereas the setup with time resolution has allowed us to determine the phosphorescence lifetime as 3 ms. Formation of 3NQNO* by intersystem crossing in solution at room temperature, has been monitored by femto-LFP, which shows the appearance of a band with maximum at 560 nm (T1-Tn). It increases with the decreasing intensity of its precursor 425 nm (S1Sn) band, giving rise to an isosbestic point at 500 nm. The characterization of 3NQNO* has been completed by nano-LFP, using xanthone as photosensitizer and oxygen as well as β-carotene as quenchers. In addition, quenching of 3NQNO* by electron donors (DABCO) is also observed in aprotic solvents, leading to the radical anion of NQNO (-NQNO). If there is a proton source in the medium (Et3N as electron donor or MeCN:H2O/4:1 as solvent system) protonation of the radical anion results in formation of the neutral radical of NQNO (NQNOH). In general, all processes are slower in protic solvents because of the solvation sphere. Overall, this information provides a deeper insight into the formation and behavior of excited states and radical ionic species derived from the title molecule NQNO.
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Affiliation(s)
- Neus Duran-Giner
- Chemistry Department, Instituto de Tecnologia Quimica, Universitat Politècnica de València, Avda de los Naranjos s/n, 46022 Valencia, Spain
| | - Benedetta Carlotti
- Department of Chemistry, Biology and Biotechnology, Università degli Studi di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Catia Clementi
- Department of Chemistry, Biology and Biotechnology, Università degli Studi di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Fausto Elisei
- Department of Chemistry, Biology and Biotechnology, Università degli Studi di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Susana Encinas
- Chemistry Department, Instituto de Tecnologia Quimica, Universitat Politècnica de València, Avda de los Naranjos s/n, 46022 Valencia, Spain.
| | - Miguel A Miranda
- Chemistry Department, Instituto de Tecnologia Quimica, Universitat Politècnica de València, Avda de los Naranjos s/n, 46022 Valencia, Spain.
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Sarkar U, Hillebrand R, Johnson KM, Cummings AH, Phung NL, Rajapakse A, Zhou H, Willis JR, Barnes CL, Gates KS. Application of Suzuki-Miyaura and Buchwald-Hartwig Cross-coupling Reactions to the Preparation of Substituted 1,2,4-Benzotriazine 1-Oxides Related to the Antitumor Agent Tirapazamine. J Heterocycl Chem 2017; 54:155-160. [PMID: 28439141 DOI: 10.1002/jhet.2559] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Many 1,2,4-benzotriazine 1,4-dioxides display the ability to selectively kill the oxygen-poor cells found in solid tumors. As a result, there is a desire for synthetic routes that afford access to substituted 1,2,4-benzotriazine 1-oxides that can be used as direct precursors in the synthesis of 1,2,4-benzotriazine 1,4-dioxides. Here we describe the use of Suzuki-Miyaura and Buchwald-Hartwig cross-coupling reactions for the construction of various 1,2,4-benzotriazine 1-oxide analogs bearing substituents at the 3-, 6-, and 7-positions.
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Affiliation(s)
- Ujjal Sarkar
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Roman Hillebrand
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Kevin M Johnson
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Andrea H Cummings
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Ngoc Linh Phung
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Anuruddha Rajapakse
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Haiying Zhou
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Jordan R Willis
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Charles L Barnes
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Kent S Gates
- University of Missouri, Department of Chemistry, 125 Chemistry Building, Columbia, MO 65211.,University of Missouri, Department of Biochemistry, 125 Chemistry Building, Columbia, MO 65211
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5
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Shen X, Rajapakse A, Gallazzi F, Junnotula V, Fuchs-Knotts T, Glaser R, Gates KS. Isotopic labeling experiments that elucidate the mechanism of DNA strand cleavage by the hypoxia-selective antitumor agent 1,2,4-benzotriazine 1,4-di-N-oxide. Chem Res Toxicol 2013; 27:111-8. [PMID: 24328261 DOI: 10.1021/tx400356y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The 1,2,4-benzotriazine 1,4-dioxides are an important class of potential anticancer drugs that selectively kill the low-oxygen (hypoxic) cells found in solid tumors. These compounds undergo intracellular one-electron enzymatic reduction to yield an oxygen-sensitive drug radical intermediate that partitions forward, under hypoxic conditions, to generate a highly reactive secondary radical that causes cell killing DNA damage. Here, we characterized bioreductively activated, hypoxia-selective DNA-strand cleavage by 1,2,4-benzotriazine 1,4-dioxide. We found that one-electron enzymatic activation of 1,2,4-benzotriazine 1,4-dioxide under hypoxic conditions in the presence of the deuterium atom donor methanol-d4 produced nondeuterated mono-N-oxide metabolites. This and the results of other isotopic labeling studies provided evidence against the generation of atom-abstracting drug radical intermediates and are consistent with a DNA-damage mechanism involving the release of hydroxyl radical from enzymatically activated 1,2,4-benzotriazine 1,4-dioxides.
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Affiliation(s)
- Xiulong Shen
- Department of Chemistry, University of Missouri , 125 Chemistry Building, Columbia, Missouri 65211, United States
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Chowdhury G, Sarkar U, Pullen S, Wilson WR, Rajapakse A, Fuchs-Knotts T, Gates KS. DNA strand cleavage by the phenazine di-N-oxide natural product myxin under both aerobic and anaerobic conditions. Chem Res Toxicol 2011; 25:197-206. [PMID: 22084973 DOI: 10.1021/tx2004213] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Heterocyclic N-oxides are an interesting class of antitumor agents that selectively kill the hypoxic cells found in solid tumors. The hypoxia-selective activity of the lead compound in this class, tirapazamine, stems from its ability to undergo intracellular one-electron reduction to an oxygen-sensitive drug radical intermediate. In the presence of molecular oxygen, the radical intermediate is back-oxidized to the parent molecule. Under hypoxic conditions, the extended lifetime of the drug radical intermediate enables its conversion to a highly cytotoxic DNA-damaging intermediate via a "deoxygenative" mechanism involving the loss of oxygen from one of its N-oxide groups. The natural product myxin is a phenazine di-N-oxide that displays potent antibiotic activity against a variety of organisms under aerobic conditions. In light of the current view of heterocyclic N-oxides as agents that selectively operate under hypoxic conditions, it is striking that myxin was identified from Sorangium extracts based upon its antibiotic properties under aerobic conditions. Therefore, we set out to examine the molecular mechanisms underlying the biological activity of myxin. We find that myxin causes bioreductively activated, radical-mediated DNA strand cleavage under both aerobic and anaerobic conditions. Our evidence indicates that strand cleavage occurs via a deoxygenative metabolism. We show that myxin displays potent cytotoxicity against the human colorectal cancer cell line HCT-116 under both aerobic and anaerobic conditions that is comparable to the cell-killing properties of tirapazamine under anaerobic conditions. This work sheds light on the processes by which the naturally occurring aromatic N-oxide myxin gains its potent antibiotic properties under aerobic conditions. Furthermore, these studies highlight the general potential for aromatic N-oxides to undergo highly cytotoxic deoxygenative metabolism following enzymatic one-electron reduction under aerobic conditions.
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Affiliation(s)
- Goutam Chowdhury
- Department of Chemistry, University of Missouri-Columbia, 125 Chemistry Building, Columbia, Missouri 65211, United States
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7
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Rajapakse A, Barnes CL, Gates KS. Synthesis and Crystal Structure of the Azoxydichinyl Helicene, Pyrido[3,2-f]quinolino[6,5-c]cinnoline 5-Oxide Monohydrate. JOURNAL OF CHEMICAL CRYSTALLOGRAPHY 2011; 41:1712-1716. [PMID: 22303091 PMCID: PMC3268207 DOI: 10.1007/s10870-011-0162-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The helicene, pyrido[3,2-f]quinolino[6,5-c]cinnoline 5-oxide, was prepared by treatment of 6-hydroxylaminoquinoline with xanthine oxidase or treatment of 6-nitroquinoline with glucose in 30% NaOH and the product characterized using NMR, high resolution mass spectrometry, and X-ray crystallography. The hydrogens on carbons 7 and 12 of the terminal aromatic rings are separated by 2.495 Å creating an angle of 25.0° between the planes of the two quinoline ring systems. In the crystal, water molecules serve to link the helicenes into a one dimensional chain structure forming a hydrogen bonded bridge between N2 of one molecule and N4 of another. The molecule (C(18)H(10)N(4)O•H(2)O) crystallized in the monoclinic P2(1)/n space group. Unit cell parameters for pyrido[3,2-f]quinolino[6,5-c]cinnoline 5-oxide monohydrate: a = 7.0829(12), b = 18.559(3), c = 11.0985(19) Å, β = 107.736(2)°, and Z = 4.
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Affiliation(s)
- Anuruddha Rajapakse
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211
| | - Charles L. Barnes
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211
| | - Kent S. Gates
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211
- Department of Biochemistry, University of Missouri-Columbia, Columbia, MO 65211
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8
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El-Gogary SR, Waly MA, Ibrahim IT, El-Sepelgy OZ. Synthesis and UV absorption of new conjugated quinoxaline 1,4-dioxide derivatives anticipated as tumor imaging and cytotoxic agents. MONATSHEFTE FUR CHEMIE 2010. [DOI: 10.1007/s00706-010-0386-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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9
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Sarkar U, Glaser R, Parsons ZD, Barnes CL, Gates KS. Synthesis, Crystal Structure, and Rotational Energy Profile of 3-Cyclopropyl-1,2,4-benzotriazine 1,4-Di-N-oxide. JOURNAL OF CHEMICAL CRYSTALLOGRAPHY 2010; 40:624-629. [PMID: 22294856 PMCID: PMC3268128 DOI: 10.1007/s10870-010-9707-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
1,2,4-Benzotriazine 1,4-di-N-oxides are potent antitumor drug candidates that undergo in vivo bioreduction leading to selective DNA damage in the low oxygen (hypoxic) cells found in tumors. Tirapazamine (TPZ) is the lead compound in this family. Here we report on the synthesis, crystal structure, and conformational analysis of a new analog, 3-cyclopropyl-1,2,4-benzotriazine 1,4-di-N-oxide (3). Compound 3 (C(10)H(10)N(3)O(2)) crystallized in the monoclinic space group C2/c. Unit cell parameters for 3: a = 16.6306 (12), b = 7.799 (5), c = 16.0113 (11) Å, α = 90, β = 119.0440 (10), γ = 90, and z = 8.
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Affiliation(s)
- Ujjal Sarkar
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211
| | - Rainer Glaser
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211
| | - Zack D. Parsons
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211
| | - Charles L. Barnes
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211
| | - Kent S. Gates
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211
- Department of Biochemistry, University of Missouri-Columbia, Columbia, MO 65211
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10
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Junnotula V, Sarkar U, Sinha S, Gates KS. Initiation of DNA strand cleavage by 1,2,4-benzotriazine 1,4-dioxide antitumor agents: mechanistic insight from studies of 3-methyl-1,2,4-benzotriazine 1,4-dioxide. J Am Chem Soc 2009; 131:1015-24. [PMID: 19117394 PMCID: PMC2819123 DOI: 10.1021/ja8049645] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The antitumor agent 3-amino-1,2,4-benzotriazine 1,4-dioxide (tirapazamine, TPZ, 1) gains medicinal activity through its ability to selectively damage DNA in the hypoxic cells found inside solid tumors. This occurs via one-electron enzymatic reduction of TPZ to yield an oxygen-sensitive drug radical (2) that leads to oxidatively generated DNA damage under hypoxic conditions. Two possible mechanisms have been considered to account for oxidatively generated DNA damage by TPZ. First, homolysis of the N-OH bond in 2 may yield the well-known DNA-damaging agent, hydroxyl radical. Alternatively, it has been suggested that elimination of water from 2 generates a benzotriazinyl radical (4) as the ultimate DNA-damaging species. In the studies described here, the TPZ analogue 3-methyl-1,2,4-benzotriazine 1,4-dioxide (5) was employed as a tool to probe the mechanism of DNA damage within this new class of antitumor drugs. Initially, it was demonstrated that 5 causes redox-activated, hypoxia-selective oxidation of DNA and small organic substrates in a manner that is completely analogous to TPZ. This suggests that 5 and TPZ damage DNA by the same chemical mechanism. Importantly, the methyl substituent in 5 provides a means for assessing whether the putative benzotriazinyl intermediate 7 is generated following one-electron reduction. Two complementary isotopic labeling experiments provide evidence against the formation of the benzotriazinyl radical intermediate. Rather, a mechanism involving the release of hydroxyl radical from the activated drug radical intermediates can explain the DNA-cleaving properties of this class of antitumor drug candidates.
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Affiliation(s)
- Venkatraman Junnotula
- University of Missouri–Columbia, Departments of Chemistry and Biochemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Ujjal Sarkar
- University of Missouri–Columbia, Departments of Chemistry and Biochemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Sarmistha Sinha
- University of Missouri–Columbia, Departments of Chemistry and Biochemistry, 125 Chemistry Building, Columbia, MO 65211
| | - Kent S. Gates
- University of Missouri–Columbia, Departments of Chemistry and Biochemistry, 125 Chemistry Building, Columbia, MO 65211
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11
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Starrs SM, H. Davies RJ. Sequence Specificity of Alkali-labile DNA Damage Photosensitized by Suprofen ‡¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2000)0720291ssoald2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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12
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Wang L, Liu J, Tian H, Qian C. Ytterbium Triflate Catalyzed Heterocyclization of 1,2‐Phenylenediamines and Alkyl Oxalates Under Solvent‐Free Conditions via Phillips Reaction: A Facile Synthesis of Quinoxaline‐2,3‐diones Derivatives. SYNTHETIC COMMUN 2006. [DOI: 10.1081/scc-120030683] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Limin Wang
- a Institute of Fine Chemicals , East China University of Science and Technology , 130 Meilong Lu, Shanghai, 200237, P.R. China
| | - Jijun Liu
- a Institute of Fine Chemicals , East China University of Science and Technology , 130 Meilong Lu, Shanghai, 200237, P.R. China
| | - He Tian
- a Institute of Fine Chemicals , East China University of Science and Technology , 130 Meilong Lu, Shanghai, 200237, P.R. China
| | - Changtao Qian
- b Laboratory of Organometallic Chemistry , Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , Shanghai, P.R. China
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Solntsev KM, Clower CE, Tolbert LM, Huppert D. 6-Hydroxyquinoline-N-oxides: A New Class of “Super” Photoacids1. J Am Chem Soc 2005; 127:8534-44. [PMID: 15941289 DOI: 10.1021/ja0514545] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
N-Oxidation of hydroxyquinolines leads to a dramatic increase in their excited-state acidity. Time-resolved and steady-state emission characterization of 6-hydroxyquinoline-N-oxide and 2-methyl-6-hydroxyquinoline-N-oxide reveals a rich but less complex proton-transfer behavior than that of its parent hydroxyquinoline. The electronic effect of the oxidized heterocyclic nitrogen atom makes the excited state both less basic and more acidic than the parent and adds hydroxyquinoline N-oxides to the class of high-acidity excited-state proton donors in photochemistry and photobiology. Adiabatic photoinduced proton transfer is accompanied by the efficient nonreversible deoxygenation and 1-2 oxygen migration.
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Affiliation(s)
- Kyril M Solntsev
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA.
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14
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Wondrak GT, Jacobson EL, Jacobson MK. Photosensitization of DNA damage by glycated proteins. Photochem Photobiol Sci 2002; 1:355-63. [PMID: 12653475 DOI: 10.1039/b202732c] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photosensitized DNA damage in skin is thought to be an important mechanism of UV phototoxicity. Here we demonstrate that proteins modified by advanced glycation endproducts (AGE-proteins) are photosensitizers of DNA damage and show that multiple mechanisms are involved in AGE-sensitization. AGE-chromophores accumulate on long-lived skin proteins such as collagen and elastin as a consequence of glycation, the spontaneous amino-carbonyl reaction of protein-bound lysine and arginine residues with reactive carbonyl species. AGE-proteins accumulate in both the nucleus and the cytoplasm of mammalian cells. To test the hypothesis that protein-bound AGEs in close proximity to DNA are potent UV-photosensitizers, a simple plasmid DNA cleavage assay was established. Irradiation of supercoiled phiX 174 DNA with solar simulated light in the presence of AGE-modified bovine serum albumin or AGE-modified RNAse A induced DNA single strand breaks. The sensitization potency of the glycated protein correlated with increased AGE-modification and the unmodified protein displayed no photosensitizing activity. AGE-sensitized formation of reactive oxygen species was not fully responsible for the observed DNA damage and other mechanisms such as direct electron transfer interaction between photoexcited AGE and DNA are likely to be involved. Glycated proteins in skin may equally function as potent photosensitizers of DNA damage with implications for photoaging and photocarcinogenesis.
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Affiliation(s)
- Georg T Wondrak
- Department of Pharmacology and Toxicology, College of Pharmacy, Arizona Cancer Center, University, of Arizona, Tucson, AZ, USA
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15
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Conlon KA, Berrios M. Light-induced proteolysis of myosin heavy chain by Rose Bengal-conjugated antibody complexes. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2001; 65:22-8. [PMID: 11748001 DOI: 10.1016/s1011-1344(01)00241-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The specific light-induced, non-enzymatic digestion of chicken skeletal muscle myosin heavy chain by xanthene dye-conjugated antibodies is reported. The xanthene dye Rose Bengal was conjugated to either a mouse monoclonal anti-myosin primary specific antibody or to goat anti-mouse IgG secondary antibodies. Under our experimental conditions, visible light induced the non-enzymatic breakdown of myosin heavy chains when chicken skeletal muscle myosin either directly formed a complex with Rose Bengal-conjugated anti-myosin antibodies or indirectly formed a complex with anti-myosin antibody-Rose Bengal-conjugated secondary antibodies. The rate of the photochemical reaction depended on irradiation time and temperature. Although SDS-PAGE and immunoblot analyses showed that fragments migrating below the myosin heavy chain polypeptide predominated, these analyses also showed higher molecular mass polypeptides were generated.
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Affiliation(s)
- K A Conlon
- Department of Pharmacological Sciences, School of Medicine, University Hospital and Medical Center, State University of New York at Stony Brook, Stony Brook, NY 11794-8651, USA.
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16
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Fuchs T, Chowdhury G, Barnes CL, Gates KS. 3-amino-1,2,4-benzotriazine 4-oxide: characterization of a new metabolite arising from bioreductive processing of the antitumor agent 3-amino-1,2,4-benzotriazine 1,4-dioxide (tirapazamine). J Org Chem 2001; 66:107-14. [PMID: 11429885 DOI: 10.1021/jo001232j] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tirapazamine (1) is a promising antitumor agent that selectively causes DNA damage in hypoxic tumor cells, following one-electron bioreductive activation. Surprisingly, after more than 10 years of study, the products arising from bioreductive metabolism of tirapazamine have not been completely characterized. The two previously characterized metabolites are 3-amino-1,2,4-benzotriazine 1-oxide (3) and 3-amino-1,2,4-benzotriazine (5). In this work, 3-amino-1,2,4-benzotriazine 4-oxide (4) is identified for the first time as a product resulting from one-electron activation of the antitumor agent tirapazamine by the enzymes xanthine/xanthine oxidase and NADPH:cytochrome P450 oxidoreductase. As part of this work, the novel N-oxide (4) was unambiguously synthesized and characterized using NMR spectroscopy, UV-vis spectroscopy, LC/MS, and X-ray crystallography. Under conditions where the parent drug tirapazamine is enzymatically activated, the metabolite 4 is produced but readily undergoes further reduction to the benzotriazine (5). Thus, under circumstances where extensive reductive metabolism occurs, the yield of the 4-oxide (4) decreases. In contrast, the isomeric two-electron reduction product 3-amino-1,2,4-benzotriazine 1-oxide (3) does not readily undergo enzymatic reduction and, therefore, is found as a major bioreductive metabolite under all conditions. Finally, the ability of the 4-oxide metabolite (4) to participate in tirapazamine-mediated DNA damage is considered.
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Affiliation(s)
- T Fuchs
- Departments of Chemistry and Biochemistry, University of Missouri-Columbia, Columbia, Missouri 65211, USA
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17
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Abstract
On irradiation at UVB wavelengths, in aerated neutral aqueous solution, the anti-inflammatory drug suprofen (SP) photosensitizes the production of alkali-labile cleavage sites in DNA much more efficiently than direct strand breaks. It is active at submillimolar concentrations despite having no significant binding affinity for DNA. Gel sequencing studies utilizing 32P-end-labeled oligonucleotides have revealed that piperidine-sensitive lesions are formed predominantly at the positions of guanine (G) bases, with the extent of modification being UV dose- and SP concentration-dependent. Quite distinct patterns of G-specific damage are observed in single-stranded and duplex DNA molecules. The uniform attack at all G residues in single-stranded DNA, which is enhanced in D2O, is compatible with a Type-II mechanism. SP is a known generator of singlet oxygen whose participation in the reaction is supported by the effects of quenchers and scavengers. In duplex DNA, piperidine-induced cleavage occurs with high selectivity at the 5'-G of GG and (less prominently) GA doublets. This behavior is characteristic of a Type-I process involving electron transfer from DNA to photoexcited SP molecules. The ability of SP to sensitize the formation of Type-I and Type-II photo-oxidation products from 2'-deoxyguanosine attests to the feasibility of competing mechanisms in DNA.
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Affiliation(s)
- S M Starrs
- School of Biology and Biochemistry, Medical Biology Center, Queen's University, Belfast, Northern Ireland
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