Peroxidase-mediated dealkylation of tamoxifen, detected by electrospray ionization-mass spectrometry, and activation to form DNA adducts.
Peroxidase-mediated dealkylation of tamoxifen, detected by electrospray ionization-mass spectrometry, and activation to form DNA adducts.
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DOI：
10.1016/j.freeradbiomed.2011.10.433
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发表时间：
2012-01-15
影响因子：
7.4
通讯作者：
Bodell, William J.
中科院分区：
文献类型：
--
作者：
Gaikwad, Nilesh W.;Bodell, William J.
他莫昔芬（TAM）广泛用于治疗和预防乳腺癌。与TAM治疗相关的是子宫内膜癌风险增加2至8倍。为了了解与这种风险增加相关的机制，研究了TAM代谢和DNA加合物形成的几种途径。这些研究的目的是研究过氧化物酶在TAM代谢及其活化形成DNA加合物中的作用。使用先进的串联质谱，我们研究了过氧化物酶介导的代谢他莫昔芬（TAM）。TAM与辣根过氧化物酶（HRP）和H2 O2孵育，产生多种代谢产物。代谢物的ESI-MS/MS分析显示在301.3 m/z处有一个峰，子离子在183.0 m/z、166.9 m/z、128.9 m/z和120.9 m/z处，将代谢物鉴别为代谢物E（ME）。向孵育混合物中添加抗坏血酸可显着抑制ME水平。将TAM或ME与DNA与HRP和H2 O2共孵育产生3种DNA加合物，其RAL分别为1.97 ± 0.01 × 10−7和8.45 ± 2.7 × 10−7。用MnO 2氧化ME产生代谢产物E醌甲基化物（MEQM）。此外，孵育的TAM或ME与HRP和H2 O2导致MEQM的形成。小牛胸腺DNA与MEQM反应产生3种DNA加合物，RAL为9.8 ± 1.0 × 10−7。再色谱分析表明，TAM或ME在HRP活化中形成的DNA加合物1、2和3与DNA与MEQM化学反应形成的DNA加合物相同。这些研究的结果表明，过氧化物酶既可以代谢TAM形成初级代谢物ME，又可以将ME活化为醌甲基化物中间体，后者与DNA反应形成加合物。TAM给药后，子宫内膜中的过氧化物酶或过氧化物酶样活性可能有助于子宫内膜DNA损伤和遗传毒性效应的形成。
Tamoxifen (TAM) is extensively used for the treatment and prevention of breast cancer. Associated with TAM treatment is a 2- to 8-fold increase in risk of endometrial cancer. To understand the mechanisms associated with this increased risk several pathways for TAM metabolism and DNA adduct formation have been studied. The purpose of these studies has been to investigate the role of peroxidase enzymes in the metabolism of TAM and its activation to form DNA adducts. Using advanced tandem mass spectrometry we have investigated peroxidase mediated metabolism of Tamoxifen (TAM) . Incubation of TAM with horseradish peroxidase (HRP) and H2O2, produced multiple metabolites. ESI-MS/MS analysis of the metabolites demonstrated a peak at 301.3 m/z with daughter ions at 183.0 m/z, 166.9 m/z 128.9 m/z and 120.9 m/z which identified the metabolite as metabolite E (ME). The levels of ME were significantly inhibited by the addition of ascorbic acid to the incubation mixture. Co-incubation of either TAM or ME and DNA with HRP and H2O2 produced 3 DNA adducts with a RAL 1.97 ± 0.01 × 10−7 and 8.45 ± 2.7 × 10−7. Oxidation of ME with MnO2 produced metabolite E quinone methide (MEQM). Furthermore, incubation of either TAM or ME with HRP and H2O2 resulted in formation of MEQM. Reaction of calf thymus DNA with MEQM produced 3 DNA adducts with a RAL of 9.8 ± 1.0 × 10−7. Rechromatography analyses indicated that DNA adducts 1, 2 and 3 formed in HRP activation of either TAM or ME were the same as those formed by chemical reaction of DNA with MEQM. The results of these studies demonstrate that peroxidase enzymes can both metabolize TAM to form the primary metabolite ME and activate ME to a quinone methide intermediate, which reacts with DNA to form adducts. It is possible that peroxidase enzymes or peroxidase-like activity in endometrium could contribute to the formation of DNA damage and genotoxic effects in endometrium following TAM administration.
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影响因子：
4.7
作者：
Davies, R;Gant, TW;Styles, JA
通讯作者：
Styles, JA
影响因子：
5.1
作者：
Gaikwad, NW;Bodell, WJ
通讯作者：
Bodell, WJ
DOI：
10.1016/s0959-8049(00)00255-0
发表时间：
2000-09-01
期刊：
European journal of cancer (Oxford, England : 1990)
影响因子：
--
作者：
Giorda;Franceschi;Furlanut
通讯作者：
Furlanut
影响因子：
3.8
作者：
Chiarelli, Anna M.;Kirsh, Victoria A.;Boyd, Norman F.
通讯作者：
Boyd, Norman F.
影响因子：
4.7
作者：
Bodell, WJ;Ye, QP;Pongracz, K
通讯作者：
Pongracz, K