Simultaneous determination of O6-methyl-2′-deoxyguanosine, 8-oxo-7,8-dihydro-2′-deoxyguanosine, and 1,N6-etheno-2′-deoxyadenosine in DNA using on-line sample preparation by HPLC column switching coupled to ESI-MS/MS

Brink, Andreas; Lutz, Ursula; Völkel, Wolfgang; Lutz, Werner

doi:10.1016/j.jchromb.2005.10.046

Cited by 46 publications

(42 citation statements)

References 30 publications

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“…However, the lack of adducts could be challenged by uncomplete DNA digestion or insufficient sensitivity, since digestion efficiency was not tested in detail with modified oligonucelotides and/or model DNA, and no internal standard was employed to accurately estimate the matrix effect. To circumvent these limitations and provide unambiguous data, it was decided to improve the LC-MS/MS quantification of dGuoOTA by focusing on the three aspects listed hereafter: (i) use of column switching technique [54] to avoid loss of sensitivity induced by matrix effects [55] and to be able to load more sample and therefore decrease the LOD, (ii) use of the isotope dilution approach (with 15 N 5 -dGuoOTA as internal standard) to ensure an accurate quantification [56], and (iii) control and optimize the enzymatic digestion with CTG OTA TC and irradiated ctDNA to ensure a complete release of the adduct as nucleoside and therefore avoid false negative responses.…”

Section: Discussionmentioning

confidence: 99%

Absence of 2′‐deoxyguanosine‐carbon 8‐bound ochratoxin A adduct in rat kidney DNA monitored by isotope dilution LC‐MS/MS

Delatour¹,

Mally

Richoz

et al. 2008

Molecular Nutrition Food Res

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The contribution of DNA adduct formation in the carcinogenic action of the mycotoxin ochratoxin A (OTA) has been subject to much debate. Recently, a carbon-bonded ochratoxin A-2'-deoxyguanosine adduct (dGuoOTA) formed by photochemical reaction in vitro has been shown by 32P-postlabeling/TLC to comigrate with a spot detected in DNA isolated from rat and pig kidney following exposure to OTA. Considering the large body of evidence arguing against covalent DNA binding of OTA and the poor resolution and specificity of postlabeling analysis, we developed a stable isotope dilution LC-MS/MS method to analyze dGuoOTA in kidney DNA isolated from rats treated with OTA. dGuoOTA and nitrogen-15-labeled dGuoOTA (15N(5)-dGuoOTA) were prepared by photoirradiation of OTA in the presence of dGuo or nitrogen-15-labeled dGuo. Conditions for DNA hydrolysis were optimized using a synthetic oligonucleotide containing dGuoOTA to ensure complete release of dGuoOTA. The LOD of the method (S/N > 3) was 10 fmol dGuoOTA on-column. However, dGuoOTA was not detected in DNA samples isolated from male F344 rats treated with OTA for up to 90 days at doses known to cause renal tumor formation. Detection limits, calculated for each individual sample based on the absolute LOD and the amount of DNA injected, were as low as 3.5 dGuoOTA/10(9) nucleotides. These data are consistent with previous results showing lack of DNA adduct formation by OTA and demonstrate that dGuoOTA is not formed in biologically relevant amounts under physiological conditions in vivo.

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Section: Discussionmentioning

confidence: 99%

Absence of 2′‐deoxyguanosine‐carbon 8‐bound ochratoxin A adduct in rat kidney DNA monitored by isotope dilution LC‐MS/MS

Delatour¹,

Mally

Richoz

et al. 2008

Molecular Nutrition Food Res

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“…Milton Winternitz, who had worked on sulfur mustards in World War I, obtained the OSRD contract to study the chemistry of mustard compounds. He recruited the pharmacologists Louis S. Goodman and Alfred Gilman Brink et al 2006;Nay 2013) to perform the necessary animal experiments. Based on their successful research, Gustav Lindskog successfully treated a radio-resistant lymphosarcoma that compressed a patient's trachea with the injection of nitrogen mustard in December 1942.…”

Section: Nitrogen Mustardsmentioning

confidence: 99%

DNA Damaging Drugs

Weber

2015

Molecular Therapies of Cancer

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The classical anti-cancer agents comprise cytotoxic compounds. Mostly, these drugs act by exerting DNA damage. In essence, there are two major response phenotypes available to a cell upon DNA damage, such as a chemotherapeutic drug action, -to arrest the cell cycle and repair the damage, -to initiate a pathway to apoptosis (programmed cell death).In either scenario, the uncontrolled growth of the tumor cells is curtailed. The major limitation of the cytotoxic anti-cancer drugs is the tumor non-specific action, and the suppression of all rapidly dividing cells 1 . Alkylating AgentsAlkylating agents 2 are electrophilic and bind covalently to electron-rich functional groups of various target molecules via first-order or second-order nucleophilic substitutions (nucleophiles are electron-rich molecules or ions, such as OH − , H 2 O, halogenides, alcohols, thiols and amines). The first order reactants include aromatic and aliphatic nitrogen and sulfur mustards. Second order reactants include ethylene 1 Because the desired drug actions (damage to rapidly proliferating cancer cells) and the adverse effects (damage to rapidly proliferating healthy cells) are identical in targets and mechanisms, they are not separable. 2 Alkyl designates a functional group (a "side chain") that consists solely of single-bonded carbon and hydrogen atoms. Alkylating anticancer agents attach alkyl groups to biomolecules. imines and epoxides, alkylmethane sulfonates of the busulfan (Myleran) type, and α-halogenated acids, ketones, and their derivatives.-For first-order reactions, the rate limiting step is the ionization of the alkylating agent to form a positively charged carbonium ion, which then rapidly reacts with water, or a negative center, or a nucleophilic center. Within DNA and RNA, the most reactive site is the N 7 position of guanine ( Fig. 2.1). In DNA, this is followed by N 3 of adenine, N 1 of adenine, N 1 of cytosine, and N 7 of adenine (Table 2.1). The rate limiting step of the reaction is the formation of positively charged cyclic immonium ions, whereas the rate of the reaction is essentially independent of the nature and concentration of the nucleophilic target being attacked. -For second order nucleophilic substitutions, both reactants interact to form a transition complex. No carbonium ion is formed. The rate of the reaction depends on both concentrations, with bond strengths, electron affinity, and accessibility of both reagents being important (Knock 1967).Alkylating agents exert cytotoxic effects by transferring alkyl groups to DNA, thereby damaging the DNA and interfering with DNA transcription and cell division. This class of drugs mainly works by three distinct mechanisms:-The attachment of alkyl groups to DNA bases prevents DNA synthesis and RNA transcription, and it results in the DNA being fragmented by repair enzymes in a process to replace the altered bases. -The two arms of mustard drugs can cross-link DNA strands. In this process, two bases are linked together. Bridges can be formed within a single molecule of...

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“…The on-line extraction LC-MS/MS system as used in our laboratory [13] was adapted to the new analytes. The autosampler (Agilent Series 1100, Waldbronn, Germany) introduced the sample (300 L) into the system and pump 1 (Agilent Series 1100) car- …”

Section: Liquid Chromatography/mass Spectrometrymentioning

confidence: 99%

Quantification of cortisol and 6 beta-hydroxycortisol in human urine by LC-MS/MS, and gender-specific evaluation of the metabolic ratio as biomarker of CYP3A activity

Lutz

Bittner

Ufer

et al. 2010

Journal of Chromatography B

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Simultaneous determination of O6-methyl-2′-deoxyguanosine, 8-oxo-7,8-dihydro-2′-deoxyguanosine, and 1,N6-etheno-2′-deoxyadenosine in DNA using on-line sample preparation by HPLC column switching coupled to ESI-MS/MS

Cited by 46 publications

References 30 publications

Absence of 2′‐deoxyguanosine‐carbon 8‐bound ochratoxin A adduct in rat kidney DNA monitored by isotope dilution LC‐MS/MS

Absence of 2′‐deoxyguanosine‐carbon 8‐bound ochratoxin A adduct in rat kidney DNA monitored by isotope dilution LC‐MS/MS

DNA Damaging Drugs

Quantification of cortisol and 6 beta-hydroxycortisol in human urine by LC-MS/MS, and gender-specific evaluation of the metabolic ratio as biomarker of CYP3A activity

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