Identification of tamoxifen-DNA adducts formed by alpha-sulfate tamoxifen and alpha-acetoxytamoxifen.
Identification of tamoxifen-DNA adducts formed by alpha-sulfate tamoxifen and alpha-acetoxytamoxifen.
复制标题
α-硫酸他莫昔芬和 α-乙酰氧基他莫昔芬形成的他莫昔芬-DNA 加合物的鉴定。
DOI：
10.1021/tx960114h
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Shibutani,S
中科院分区：
文献类型：
--
作者：
Dasaradhi,L;Shibutani,S
合成了 α-硫酸反式-他莫昔芬和 α-硫酸顺式-他莫昔芬，作为与 DNA 反应的他莫昔芬活性代谢物。 α-Acetoxytamoxifen 被制备为模型激活形式，以产生反应性碳正离子。小牛胸腺 DNA 与 α-羟基他莫昔芬或他莫昔芬的活化形式反应，并通过 32P 后标记方法分析他莫昔芬-DNA 加合物。 α-硫酸酯反式-他莫昔芬对DNA的反应性远高于α-羟基他莫昔芬。 α-乙酰氧基他莫昔芬和α-硫酸顺-他莫昔芬诱导的他莫昔芬-DNA加合物的形成分别比α-羟基他莫昔芬高1100倍和1600倍。 α-硫酸他莫昔芬和α-乙酰氧基他莫昔芬均与2'-脱氧鸟苷高度反应。通过 HPLC 分离 dG-他莫昔芬的四种反应产物，并通过质谱和质子磁共振波谱进行表征。首先洗脱的级分1和2被鉴定为dG-N2-他莫昔芬转化的差向异构体。级分3和4被鉴定为dG-N2-他莫昔芬的顺式差向异构体。当 DNA 与 α-乙酰氧基他莫昔芬体外反应时，检测到 dG-N2-他莫昔芬的三种异构体： 级分 2 是主要加合物，级分 1 和 3 是次要加合物。
α-Sulfatetrans-tamoxifen and α-sulfatecis-tamoxifen were synthesized as proposed active metabolites of tamoxifen that react with DNA. α-Acetoxytamoxifen was prepared as a model-activated form to produce a reactive carbocation. Calf thymus DNA was reacted with α-hydroxytamoxifen or the activated forms of tamoxifen, and tamoxifen−DNA adducts were analyzed by a32P-postlabeling method. The reactivity of α-sulfatetrans-tamoxifen to DNA was much higher than that of α-hydroxytamoxifen. The formation of tamoxifen−DNA adducts induced by α-acetoxytamoxifen and α-sulfatecis-tamoxifen was 1100- and 1600-fold, respectively, higher than that of α-hydroxytamoxifen. Both α-sulfate tamoxifens and α-acetoxytamoxifen were highly reactive to 2‘-deoxyguanosine. Four reaction products of dG-tamoxifen were isolated by HPLC and characterized by mass- and proton magnetic resonance spectroscopy. Fractions 1 and 2 that eluted first were identified as the epimers oftransform of dG-N2-tamoxifen. Fractions 3 and 4 were identified as the epimers ofcisform of dG-N2-tamoxifen. When DNA was reacted with α-acetoxytamoxifenin vitro, three isomers of dG-N2-tamoxifen were detected: fraction 2 was the major adduct while fractions 1 and 3 were minor adducts.