In Vitro Metabolism of 17-(Dimethylaminoethylamino)-17-demethoxygeldanamycin in Human Liver Microsomes
作者:Nan Zheng、Peng Zou、Shaomeng Wang、Duxin Sun
DOI:10.1124/dmd.110.036418
日期:2011.4
The objective of this study was to investigate the oxidative metabolism pathways of 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin (17-DMAG), a geldanamycin (GA) derivative and 90-kDa heat shock protein inhibitor. In vitro metabolic profiles of 17-DMAG were examined by using pooled human liver microsomes (HLMs) and recombinant CYP450 isozymes in the presence or absence of reduced GSH. In addition to 17-DMAG hydroquinone and 19-glutathionyl 17-DMAG, several oxidative metabolites of 17-DMAG were detected and characterized by liquid chromatography-tandem mass spectrometry. Different from previously reported primary biotransformations of GA and GA derivatives, 17-DMAG was not metabolized primarily through the reduction of benzoquinone and GSH conjugation in HLMs. In contrast, the primary biotransformations of 17-DMAG in HLMs were hydroxylation and demethylation on its side chains. The most abundant metabolite was produced by demethylation from the methoxyl at position 12. The reaction phenotyping study showed that CYP3A4 and 3A5 were the major cytochrome P450 isozymes involved in the oxidative metabolism of 17-DMAG, whereas CYP2C8, 2D6, 2A6, 2C19, and 1A2 made minor contributions to the formation of metabolites. On the basis of the identified metabolite profiles, the biotransformation pathways for 17-DMAG in HLMs were proposed.
本研究旨在探讨17-(二甲基氨基乙氨基)-17-去甲氧基格尔德霉素(17-DMAG)的氧化代谢途径,该物质是一种格尔德霉素(GA)衍生物及90 kDa热休克蛋白抑制剂。通过使用人肝微粒体(HLMs)和重组CYP450同工酶,在有无还原型谷胱甘肽(GSH)的存在下,对17-DMAG的体外代谢谱进行了研究。除了17-DMAG氢醌和19-谷胱甘肽17-DMAG外,通过液相色谱-串联质谱法检测并鉴定了17-DMAG的几种氧化代谢物。与先前报道的GA和GA衍生物的主要生物转化方式不同,17-DMAG在HLMs中并非主要通过苯醌还原和GSH结合进行代谢。相反,17-DMAG在HLMs中的主要生物转化方式是其侧链的羟基化和去甲基化。最丰富的代谢物是由12位甲氧基的去甲基化产生的。反应表型研究显示,CYP3A4和3A5是参与17-DMAG氧化代谢的主要细胞色素P450同工酶,而CYP2C8、2D6、2A6、2C19和1A2对代谢物的形成贡献较小。基于所识别的代谢物谱,提出了17-DMAG在HLMs中的生物转化途径。