The prototypic pharmacogenetic drug debrisoquine is a substrate of the genetically polymorphic organic cation transporter OCT1
The prototypic pharmacogenetic drug debrisoquine is a substrate of the genetically polymorphic organic cation transporter OCT1
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DOI：
10.1016/j.bcp.2012.01.032
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发表时间：
2012-05-15
影响因子：
5.8
通讯作者：
Tzvetkov, Mladen V.
中科院分区：
文献类型：
--
作者：
Saadatmand, Ali R.;Tadjerpisheh, Sina;Tzvetkov, Mladen V.
碎片喹是人体CYP2D6代谢活性体内表型的探测药物。然而，碎屑喹在生理条件下带正电，其如何进入肝细胞进行CYP2D6代谢尚不清楚。我们分析了碎屑喹是否是肝脏有机阳离子转运体OCT1的底物，以及OCT1上的药物相互作用或OCT1基因多态性是否影响碎屑喹的摄取。在人工PAMPA膜中，de - isquine具有较低的非载体膜透性（P-e为0.01 x 10(-6) cm/s），并强烈抑制模型OCT1底物MPP+的吸收（IC50为6.2 +/- 0.8 μ M）。与对照细胞相比，过表达OCT1的HEK293细胞的碎屑喹摄取显著增加。OCT1介导的de - isquine摄取遵循Michaelis-Menten动力学（K-M为5.9 +/- 1.5 μ M， V-max为41.9 +/- 4.5 pmol/min/mg蛋白），并被已知的OCT1抑制剂和常用药物抑制。在表达功能缺失的OCT1亚型的细胞中，OCT1介导的碎屑喹摄取减少或缺失。缺失Met420或替换Arg61Cys或Gly401Ser分别使V-max降低了48%、63%和91%，但对K-M没有影响。携带Cys88Arg或Gly465Arg取代的OCT1亚型完全缺乏OCT1介导的碎屑喹摄取。综上所述，碎屑喹是OCT1的底物，有潜力作为OCT1活性的表型标记物。此外，碎片喹代谢表型的变化及其与疾病的关联可能不仅与CYP2D6的遗传变异有关，还与OCT1的遗传变异有关。(C) 2012爱思唯尔公司版权所有。
Debrisoquine is a probe drug for in vivo phenotyping of human CYP2D6 metabolic activity. However, debrisoquine is positively charged under physiological conditions and it is unclear how it enters the hepatocytes to undergo CYP2D6 metabolism. We analysed whether debrisoquine is a substrate of the hepatic organic cation transporter OCT1 and whether drug-drug interactions at OCT1, or polymorphisms in OCT1 gene, affect debrisoquine uptake.Debrisoquine showed low carrier-independent membrane permeability (P-e of 0.01 x 10(-6) cm/s in artificial PAMPA membranes) and strongly inhibited the uptake of the model OCT1 substrate MPP+ (IC50 of 6.2 +/- 0.8 mu M). Debrisoquine uptake was significantly increased in HEK293 cells overexpressing OCT1 compared to control cells. The OCT1-mediated uptake of debrisoquine followed Michaelis-Menten kinetics (K-M of 5.9 +/- 1.5 mu M and V-max of 41.9 +/- 4.5 pmol/min/mg protein) and was inhibited by known OCT1 inhibitors and by commonly used drugs. OCT1-mediated debrisoquine uptake was reduced or missing in cells expressing loss-of-function OCT1 isoforms. Deletion of Met420 or substitution of Arg61Cys or Gly401Ser reduced V-max by 48,63 and 91%, respectively, but did not affect the K-M. The OCT1 isoforms carrying Cys88Arg or Gly465Arg substitutions completely lacked OCT1-mediated debrisoquine uptake.In conclusion, debrisoquine is a substrate of OCT1 and has the potential to be used as a phenotyping marker for OCT1 activity. Moreover, variations in debrisoquine metabolic phenotypes and their associations with diseases may be due not only to genetic variations CYP2D6, but also in OCT1. (C) 2012 Elsevier Inc. All rights reserved.