Regulation of CYP2B6 in primary human hepatocytes by prototypical inducers
Regulation of CYP2B6 in primary human hepatocytes by prototypical inducers
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DOI：
10.1124/dmd.32.3.348
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发表时间：
2004-03-01
影响因子：
3.9
通讯作者：
LeCluyse, EL
中科院分区：
文献类型：
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作者：
Faucette, SR;Wang, HB;LeCluyse, EL
本研究的目的是评估14种不同激活人孕烷X受体(HPXR)的化合物诱导CYP2B6表达的能力，并比较不同诱导剂对CYP2B6和CYP3A4的浓度和时间依赖性的诱导作用。三种原代人肝细胞制剂每天用三种浓度的所有化合物处理3天。克霉唑、苯妥英、苯巴比妥和利福平在6种制剂中进行了额外的浓度和/或时间反应研究。用Western blotting、安非他酮羟化和睾酮6β羟化分别检测细胞色素P450 2B6和细胞色素P3A4的蛋白和活性。为了评价14个化合物对hPXR的激活作用，将hPXR与报告基因CYP2B6(NR1)(5)-Luc共转染Huh7细胞进行了报告基因检测。克霉唑、苯巴比妥、利福平、利托那韦强诱导CYP2B6，激活hPXR；地塞米松、醋酸叔丁酯、磺胺吡宗诱导弱激活hPXR；紫杉醇强激活hPXR，但不增加其表达；卡马西平、苯妥英钠中或强刺激，但弱激活hPXR；地塞米松、甲氨蝶呤、丙磺舒、磺胺、曲莱霉素弱激活或可忽略不影响。克霉唑、苯巴比妥、苯妥英钠和利福平诱导的细胞色素P450值呈正相关(r(2)=0.99)，而对克霉唑、苯妥英钠和利福平的EC50值无统计学意义。控制苯巴比妥和利福平时间依赖性诱导的动力学常数在CYP2B6和CYP3A4之间也是相似的。这些结果表明，已知的CYP3A4诱导剂高度诱导了CYP2B6的表达，并表明hPXR是本研究中评估的许多(但不是所有)化合物诱导表达的主要决定因素。
The objectives of this study were to evaluate the ability of 14 compounds, which differentially activate human pregnane X receptor (hPXR), to induce CYP2B6 expression and to compare CYP2B6 and CYP3A4 concentration- and time-dependent induction by select inducers. Three primary human hepatocyte preparations were treated daily for 3 days with three concentrations of all compounds. Additional concentration- and/or time-response studies were conducted with clotrimazole, phenytoin, phenobarbital, and rifampin in six preparations. CYP2B6 and CYP3A4 protein and activities were assessed by Western blotting, bupropion hydroxylation, and testosterone 6beta-hydroxylation, respectively. To evaluate hPXR activation by the 14 compounds, reporter gene assays were conducted using Huh7 cells cotransfected with hPXR and a CYP2B6 (NR1)(5)-LUC reporter plasmid. Clotrimazole, phenobarbital, rifampin, and ritonavir strongly induced CYP2B6 and activated hPXR; dexamethasone t-butylacetate and sulfinpyrazone induced CYP2B6 weakly and activated hPXR moderately; paclitaxel strongly activated hPXR but did not increase CYP2B6 expression; carbamazepine and phenytoin moderately or strongly increased CYP2B6 expression but weakly activated hPXR; and dexamethasone, methotrexate, probenecid, sulfadimidine, and troleandomycin demonstrated weak or negligible effects on CYP2B6 and hPXR. EC50 values for CYP2B6 and CYP3A4 induction by clotrimazole, phenobarbital, phenytoin, and rifampin were strongly correlated (r(2) = 0.99) and were statistically indistinguishable for clotrimazole, phenytoin, and rifampin. Kinetic constants governing time-dependent induction by phenobarbital and rifampin were also similar between CYP2B6 and CYP3A4. These results indicate that CYP2B6 is highly inducible by known CYP3A4 inducers and suggest that hPXR is a major determinant of CYP2B6-inducible expression for many, but not all, compounds evaluated in this study.