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Wagner JR, Madugundu GS, Cadet J. Ozone-Induced DNA Damage: A Pandora's Box of Oxidatively Modified DNA Bases. Chem Res Toxicol 2021; 34:80-90. [PMID: 33417438 DOI: 10.1021/acs.chemrestox.0c00342] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Ozone is a major component of air pollution and carries potentially mutagenic and harmful affects to health. The oxidation of isolated calf thymus DNA (CT-DNA) led to the nearly quantitative loss of normal DNA 2'-deoxyribonucleosides in the following order: T > G > C ≫ A. The major modification of pyrimidines (T, C, and 5-methylcytosine (5mC)) was the corresponding 5-hydroxyhydantoin derivative after complete digestion of DNA to its component 2'-deoxyribonucleosides. The oxidation of 5mC was 2.5-fold more susceptible than C considering the relative mole fraction of 5mC to C in CT-DNA. Other common oxidation products of pyrimidines (e.g., 5,6-dihydroxy-5,6-dihydropyrimidines, the so-called pyrimidine 5,6-glycols) were formed with a lower yield than 5-hydroxyhydantoin derivatives. In addition, several common oxidation products of G were observed (e.g., 8-oxo-7,8-dihydroguanine (8oxoG)) albeit with relatively minor yields. The sum of individual products was notably less than the loss of 2'-deoxyribonucleosides from which they were derived. In a search for additional products, we discovered the formation of pyrimidine ring fragments, predominantly N-formamide and N-urea, which were measured as a dinucleotide next to a nonmodified nucleotide upon partial digestion of oxidized DNA. Interestingly, the latter fragments were also observed in dinucleotides containing 8oxoG, indicating the formation of tandem lesions during ozonolysis of DNA. The oxidation of DNA upon exposure to ozone can be explained by reactions of an intermediate ozonide. These studies underline the complexity of ozone-induced DNA damage and provide valuable information to assess the formation of this damage in cellular DNA.
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Affiliation(s)
- J Richard Wagner
- Département de Médecine nucléaire et Radiobiologie, Faculté de Médecine, Université de Sherbrooke, 3001 12e avenue Nord, Sherbrooke, Québec, Canada J1H 5N4
| | - Guru S Madugundu
- Département de Médecine nucléaire et Radiobiologie, Faculté de Médecine, Université de Sherbrooke, 3001 12e avenue Nord, Sherbrooke, Québec, Canada J1H 5N4
| | - Jean Cadet
- Département de Médecine nucléaire et Radiobiologie, Faculté de Médecine, Université de Sherbrooke, 3001 12e avenue Nord, Sherbrooke, Québec, Canada J1H 5N4
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Gong L. Analysis of oligonucleotides by ion-pairing hydrophilic interaction liquid chromatography/electrospray ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:2125-2134. [PMID: 28972295 DOI: 10.1002/rcm.8004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 09/18/2017] [Accepted: 09/25/2017] [Indexed: 06/07/2023]
Abstract
RATIONALE Hydrophilic interaction liquid chromatography/electrospray ionization mass spectrometry (HILIC-LC/ESI-MS) has been proved to be useful for the quality control of oligonucleotides. However, the lack of separation for some oligonucleotides using HILIC-LC/MS has proved problematic. This study aimed to improve the resolving ability of HILIC-LC/MS. METHODS The study was performed on a Waters UPLC® system coupled to a Waters LCT premier XE ESI-TOF mass spectrometer using a Zorbax® RRHD HILIC column (2.1 mm × 100 mm, 1.8 μm). Buffer systems contained triethylammonium acetate (TEAA) and acetonitrile. The effects of the concentration of TEAA and the type of organic modifiers on the separation of oligonucleotides were investigated. RESULTS The results showed that the optimum concentration of TEAA is 10 mM and acetonitrile is a better organic solvent than methanol. The addition of TEAA in the HILIC mobile phase improved the separation of N from N + A significantly compared to the HILIC method buffered with ammonium acetate. The IP-HILIC chromatography has demonstrated that the separation of oligonucleotides is sequence dependent. In addition, the IP-HILIC method produces a much simpler mass spectrum of an oligonucleotide with very efficient desalting. CONCLUSIONS The HILIC-LC/MS method with the addition of TEAA at a MS-compatible concentration has improved the separation of oligonucleotides. The IP-HILIC-LC/MS method also produces very simple mass spectra with high desalting efficiency.
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Affiliation(s)
- Lingzhi Gong
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
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Gong L, McCullagh JSO. Comparing ion-pairing reagents and sample dissolution solvents for ion-pairing reversed-phase liquid chromatography/electrospray ionization mass spectrometry analysis of oligonucleotides. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2014; 28:339-350. [PMID: 24395501 DOI: 10.1002/rcm.6773] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 09/19/2013] [Accepted: 10/20/2013] [Indexed: 06/03/2023]
Abstract
RATIONALE A sensitive and selective liquid chromatography/mass spectrometry (LC/MS) method is essential for quality control of synthetic oligonucleotides. However, researchers are still searching for improvements to ion-pairing reagents for ion-pairing reversed-phase LC/MS. This study performed a comprehensive comparison of six ion-pairing reagents to determine their performance as mobile phase modifiers for oligonucleotide LC/MS. METHODS The study was performed using a Waters ultra-performance liquid chromatography (UPLC®) system coupled to a Waters LCT premier XE ESI-TOF mass spectrometer by using a UPLC® OST column (2.1 mm × 100 mm, 1.7 µm). Buffer systems containing ion-pairing reagents (triethylamine, tripropylamine, hexylamine, N,N-dimethylbutylamine, dibutylamine, N,N-diisopropylethylamine) and hexafluoro-2-propanol were compared by measuring the adduct ion formation, chromatographic separation, and MS signal intensity of four oligonucleotides (10mer to 40mer). The effect of dissolution solvents on MS signal intensity and adduct ion formation was also investigated. RESULTS Results showed that the type of dissolution solvent can have a signficiant impact on adduct ion formation with oligonucleotides. Results also showed that the maximum separation for small, medium and large oligonucleotides occured when using tripropylamine, N,N-dimethylbutylamine, and dibutylamine, respectively. However, on average 15 mM hexylamine and 50 mM hexafluoro-2-propanol provided the best chromtatographic performance (resolution values: 14.1 ± 0.34, 11.0 ± 0.17, and 6.4 ± 0.11 for the pairs of oligonucleotides T10 & T15, T15 & T25, and T25 & T40, respectively (3 replicates)). CONCLUSIONS The impact of dissolution solvent on the MS signal of oligonucleotides depends on the type of ion-pairing reagent. Buffer combining 15 mM hexylamine and 50 mM hexafluoro-2-propanol produced the highest overall performance for oligonucleotides (10mer to 40mer) with respect to chromatographic resolution and mass detection.
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Affiliation(s)
- Lingzhi Gong
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK
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Liu Y, Wang R, Ding L, Sha R, Seeman NC, Canary JW. Templated synthesis of nylon nucleic acids and characterization by nuclease digestion. Chem Sci 2012; 3:1930-1937. [PMID: 23125913 PMCID: PMC3486707 DOI: 10.1039/c2sc20129a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Nylon nucleic acids containing oligouridine nucleotides with pendent polyamide linkers and flanked by unmodified heteronucleotide sequences were prepared by DNA templated synthesis. Templation was more efficient than the single-stranded synthesis: Coupling step yields were as high as 99.2%, with up to 7 amide linkages formed in the synthesis of a molecule containing 8 modified nucleotides. Controlled digestion by calf spleen phosphodiesterase enabled the mapping of modified nucleotides in the sequences. A combination of complete degradation of nylon nucleic acids by snake venom phosphodiesterase and dephosphorylation of the resulting nucleotide fragments by bacterial alkaline phosphatase, followed by LCMS analysis, clarified the linear structure of the oligo-amide linkages. The templated synthesis strategy afforded nylon nucleic acids in the target structure and was compatible with the presence heteronucleotides. The complete digestion procedure produced a new species of DNA analogues, nylon ribonucleosides, which display nucleosides attached via a 2'-alkylthio linkage to each diamine and dicarboxylate repeat unit of the original nylon nucleic acids. The binding affinity of a nylon ribonucleoside octamer to the complementary DNA was evaluated by thermal denaturing experiments. The octamer was found to form stable duplexes with an inverse dependence on salt concentration, in contrast to the salt-dependent DNA control.
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Affiliation(s)
- Yu Liu
- Department of Chemistry, New York University, New York, NY 10003, USA, Fax: +1 212 995 4367; Tel: +1 212998 8422
| | - Risheng Wang
- Department of Chemistry, New York University, New York, NY 10003, USA, Fax: +1 212 995 4367; Tel: +1 212998 8422
| | - Liang Ding
- Department of Chemistry, New York University, New York, NY 10003, USA, Fax: +1 212 995 4367; Tel: +1 212998 8422
| | - Roujie Sha
- Department of Chemistry, New York University, New York, NY 10003, USA, Fax: +1 212 995 4367; Tel: +1 212998 8422
| | - Nadrian C. Seeman
- Department of Chemistry, New York University, New York, NY 10003, USA, Fax: +1 212 995 4367; Tel: +1 212998 8422
| | - James W. Canary
- Department of Chemistry, New York University, New York, NY 10003, USA, Fax: +1 212 995 4367; Tel: +1 212998 8422
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Gong L, McCullagh JSO. Analysis of oligonucleotides by hydrophilic interaction liquid chromatography coupled to negative ion electrospray ionization mass spectrometry. J Chromatogr A 2011; 1218:5480-6. [PMID: 21741051 DOI: 10.1016/j.chroma.2011.06.044] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 05/31/2011] [Accepted: 06/09/2011] [Indexed: 01/08/2023]
Abstract
Hydrophilic interaction liquid chromatography (HILIC) is here successfully coupled to negative-ion electrospray ionization time-of-flight mass spectrometry (ESI-TOFMS) for the analysis of synthetic and chemically modified oligonucleotides. Separation was performed on a 2.1 mm × 100 mm PEEK ZIC HILIC column packed with hydrophilic stationary phase with a permanent zwitterionic functional group and a particle size of 3.5 μm with an average pore diameter of 200Å. A method was developed to separate homogeneous and heterogeneous oligonucleotides as well as methylated oligonucleotides using a quaternary pumping system containing ammonium acetate and water with an acetonitrile gradient. Analyses of oligonucleotides were performed by LC/MS with a detection limit of 2.5 picomole (20 mer) with signal to noise ratio (S/N) of 4.12. The influence of the eluent composition, type of buffer and its concentration, and organic modifier were also evaluated. The HILIC LC/MS method presented in this paper used common, 'MS friendly', mobile phases achieving sensitive and selective oligonucleotide analysis.
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Affiliation(s)
- Lingzhi Gong
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
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Metallofullerene nanoparticles circumvent tumor resistance to cisplatin by reactivating endocytosis. Proc Natl Acad Sci U S A 2010; 107:7449-54. [PMID: 20368438 DOI: 10.1073/pnas.0909707107] [Citation(s) in RCA: 177] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Cisplatin is a chemotherapeutic drug commonly used in clinics. However, acquired resistance confines its application in chemotherapeutics. To overcome the acquired resistance to cisplatin, it is reasoned, based on our previous findings of mediation of cellular responses by [Gd@C(82)(OH)(22)](n) nanoparticles, that [Gd@C(82)(OH)(22)](n) may reverse tumor resistance to cisplatin by reactivating the impaired endocytosis of cisplatin-resistant human prostate cancer (CP-r) cells. Here we report that exposure of the CP-r PC-3-luc cells to cisplatin in the presence of nontoxic [Gd@C(82)(OH)(22)](n) not only decreased the number of surviving CP-r cells but also inhibited growth of the CP-r tumors in athymic nude mice as measured by both optical and MRI. Labeling the CP-r PC-3 cells with transferrin, an endocytotic marker, demonstrated that pretreatment of the CP-r PC-3-luc cells with [Gd@C(82)(OH)(22)](n) enhanced intracellular accumulation of cisplatin and formation of cisplatin-DNA adducts by restoring the defective endocytosis of the CP-r cancer cells. The results suggest that [Gd@C(82)(OH)(22)](n) nanoparticles overcome tumor resistance to cisplatin by increasing its intracellular accumulation through the mechanism of restoring defective endocytosis. The technology can be extended to other challenges related to multidrug resistance often found in cancer treatments.
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Greene KF, Budzinski EE, Iijima H, Dawidzik JB, DeFedericis HC, Patrzyc HB, Evans MS, Bailey DT, Freund HG, Box HC. Assessment of DNA damage at the dimer level: measurement of the formamide lesion. Radiat Res 2007; 167:146-51. [PMID: 17390722 DOI: 10.1667/rr0693.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
UVC-radiation-induced DNA damage was measured in mouse fibroblast cells using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in conjunction with isotopically labeled internal standards. The thymine glycol and formamide lesions were assayed in the form of modified dinucleoside monophosphates. The 8-oxo-7,8-dihydroguanine lesion was measured as the modified nucleoside. DNA damage in cells treated with tirapazamine was also measured. Tirapazamine is a chemotherapeutic agent that acts via a free radical mechanism. The two agents, UVC radiation and tirapazamine, produce markedly different profiles of DNA damage, reflecting their respective mechanisms of action. Both agents produce significant amounts of thymine glycol and formamide damage, but only the former produced a measurable amount of the 8-oxo-7,8-dihydroguanine lesion. The merits of measuring DNA damage at the dimer level are discussed.
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Affiliation(s)
- Kellee F Greene
- Roswell Park Cancer Institute, Cellular Stress Biology, Buffalo, New York 14263, USA
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Iijima H, Patrzyc HB, Dawidzik JB, Budzinski EE, Cheng HC, Freund HG, Box HC. Measurement of DNA adducts in cells exposed to cisplatin. Anal Biochem 2004; 333:65-71. [PMID: 15351281 DOI: 10.1016/j.ab.2004.06.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2004] [Indexed: 10/26/2022]
Abstract
The two main cisplatin-induced DNA lesions, G--G and A--G, have been measured in cells exposed to the drug. (G--G and A--G denote the intrastrand bifunctional adducts formed between adjacent purine bases.) It has proven feasible, using liquid chromatography-tandem mass spectrometry (LC-MS/MS), observe the G--G and A--G lesions in mouse fibroblast cells exposed for 1 h to a 120 microM concentration of cisplatin. After extraction of the DNA from the cells, the lesions were enzymatically isolated from the DNA in the form of modified dinucleoside monophosphates with the phosphodiester bond intact. MS/MS detection of the modified dinucleoside monophosphates in the negative ion mode manifests two transitions; from the negative ion to the loss of one NH(3) group and from the ion less one NH(3) group to the loss of both NH(3) groups. The multiple reaction monitoring capability of LC-MS/MS was used to measure the three most abundant isotopes of the two main lesions for both transitions of each lesion (i.e., 12 MS/MS values in toto). Ion currents could be detected for all 12 pairs of MS/MS values in the DNA from exposed cells. Although this protocol results in some overlap of MS/MS values between the two lesions, a slight difference in elution times clearly distinguishes between them.
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Dawidzik JB, Patrzyc HB, Iijima H, Budzinski EE, Higbee AJ, Cheng HC, Box HC. DNA damage measured by liquid chromatography-mass spectrometry in mouse fibroblast cells exposed to oxidative stress. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1621:211-7. [PMID: 12726997 DOI: 10.1016/s0304-4165(03)00071-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Oxidative DNA damage can result from environmental factors, such as radiation, as well as from the untoward consequences of normal metabolic processes. It is of interest to assay oxidative DNA damage in cells and tissues because this damage has been implicated in human disease, particularly cancer. Eleven indicators of oxidative DNA damage have been measured by Liquid Chromatography-Mass Spectrometry (LC-MS) in DNA extracted from cells exposed to oxidative stress. Mouse fibroblast cells were exposed to hydrogen peroxide and to UVC light and to the combined action of both agents. Significant increases of the 8-oxo-7,8-dihydropurine lesions over background were detected. Significant increases of the formamido lesions resulting from breakdown of pyrimidine bases were also observed. Of special interest was the observation of double lesions, tandem combinations of both aforementioned lesions, in cells exposed to oxidative stress.
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Affiliation(s)
- Jean B Dawidzik
- Department of Molecular and Cellular Biophysics, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA
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Current literature in journal of mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2003; 38:235-244. [PMID: 12577291 DOI: 10.1002/jms.417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
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