The peripheral benzodiazepine receptor ligand 1-(2-chlorophenyl-methylpropyl)-3-isoquinoline-carboxamide is a novel antagonist of human constitutive androstane receptor
The peripheral benzodiazepine receptor ligand 1-(2-chlorophenyl-methylpropyl)-3-isoquinoline-carboxamide is a novel antagonist of human constitutive androstane receptor
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DOI：
10.1124/mol.108.046656
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发表时间：
2008-08-01
影响因子：
3.6
通讯作者：
Wang, Hongbing
中科院分区：
文献类型：
--
作者：
Li, Linhao;Chen, Tao;Wang, Hongbing
组成型雄甾烷受体（CAR; NR 1 I3）作为一种混杂的外源性物质感受器，调节肝脏多种药物代谢酶和转运蛋白的表达。CAR在基于细胞的转染测定中的组成型活化性质阻碍了其作为基于代谢的药物-药物相互作用的预测因子的用途。在这里，我们已经鉴定了1-（2-氯苯甲基丙基）-3-异喹啉-甲酰胺（PK 11195），一种典型的外周苯二氮卓受体（PBR）配体，作为人（h）CAR的选择性和有效抑制剂。在基于细胞的转染试验中，PK 11195在10 μ M浓度下抑制hCAR的组成性活性超过80%，并且PK 11195抑制的活性被直接CAR激活剂6-（4-氯苯基）咪唑并[2，1-B][1，3]噻唑-5-卡巴肼-O-（3，4-二氯苄基）肟有效地再激活，但不被间接hCAR激活剂苯巴比妥激活。哺乳动物双杂交和GST pull-down实验表明，PK 11195可抑制hCAR与类固醇受体辅激活因子1（steroid receptor coactivator-1）和糖皮质激素受体相互作用蛋白1（glucocorticoid receptor interacting protein 1）的相互作用，从而抑制hCAR活性。PK 11195的抑制作用特异性地发生在hCAR上：PK 1195强烈地激活了人黑色素X受体（PXR），而它没有改变小鼠CAR和小鼠PXR的活性。此外，PBR在PK 11195对hCAR的抑制中不起作用，因为抑制完全发生在HeLa细胞中，其中PBR被小干扰RNA敲低。在Car（-/-）小鼠肝脏中，PK 11195将增强型黄色荧光蛋白-hCAR易位到细胞核中。这些结果与以下结论一致：PK 11195是一种新型hCAR特异性拮抗剂，其抑制CAR-共激活因子相互作用以抑制细胞核内的受体活性。因此，PK 11195可以用作研究CAR功能的分子基础的化学工具。
As a promiscuous xenobiotic sensor, the constitutive androstane receptor (CAR; NR1I3) regulates the expression of multiple drug-metabolizing enzymes and transporters in liver. The constitutively activated nature of CAR in the cell-based transfection assays has hindered its use as a predictor of metabolism-based drug-drug interactions. Here, we have identified 1-(2-chlorophenylmethylpropyl)-3- isoquinoline-carboxamide (PK11195), a typical peripheral benzodiazepine receptor (PBR) ligand, as a selective and potent inhibitor of human (h) CAR. In cell-based transfection assays, PK11195 inhibited the constitutive activity of hCAR more than 80% at the concentration of 10 mu M, and the PK11195-inhibited activity was efficiently reactivated by the direct CAR activator, 6-(4-chlorophenyl) imidazo[2,1-b][1,3] thiazole-5-carbaldehyde-O-(3,4-dichlorobenzyl) oxime, but not by the indirect hCAR activator, phenobarbital. Mammalian two-hybrid and GST pull-down assays showed that PK11195 repressed the interactions of hCAR with the coactivators steroid receptor coactivator-1 and glucocorticoid receptor-interacting protein 1 to inhibit hCAR activity. The inhibition by PK11195 specifically occurred to the hCAR: PK1195 strongly activated human pregnane X receptor (PXR), whereas it did not alter the activity of the mouse CAR and mouse PXR. In addition, PBR played no role in the PK11195 inhibition of hCAR because the inhibition fully occurred in the HeLa cells in which the PBR was knocked down by small interfering RNA. In the Car(-/-) mouse liver, PK11195 translocated enhanced yellow fluorescent protein-hCAR into the nucleus. These results are consistent with the conclusion that PK11195 is a novel hCAR-specific antagonist that represses the CAR-coactivator interactions to inhibit the receptor activity inside the nucleus. Thus, PK11195 can be used as a chemical tool for studying the molecular basis of CAR function.