Identifying a Selective Substrate and Inhibitor Pair for the Evaluation of CYP2J2 Activity
作者:Caroline A. Lee、J. P. Jones、Jonathan Katayama、Rüdiger Kaspera、Ying Jiang、Sascha Freiwald、Evan Smith、Gregory S. Walker、Rheem A. Totah
DOI:10.1124/dmd.111.043505
日期:2012.5
CYP2J2, an arachidonic acid epoxygenase, is recognized for its role in the first-pass metabolism of astemizole and ebastine. To fully assess the role of CYP2J2 in drug metabolism, a selective substrate and potent specific chemical inhibitor are essential. In this study, we report amiodarone 4-hydoxylation as a specific CYP2J2-catalyzed reaction with no CYP3A4, or other drug-metabolizing enzyme, involvement. Amiodarone 4-hydroxylation enabled the determination of liver relative activity factor and intersystem extrapolation factor for CYP2J2. Amiodarone 4-hydroxylation correlated with astemizole O-demethylation but not with CYP2J2 protein content in a sample of human liver microsomes. To identify a specific CYP2J2 inhibitor, 138 drugs were screened using terfenadine and astemizole as probe substrates with recombinant CYP2J2. Forty-two drugs inhibited CYP2J2 activity by ≥50% at 30 μM, but inhibition was substrate-dependent. Of these, danazol was a potent inhibitor of both hydroxylation of terfenadine (IC50 = 77 nM) and O-demethylation of astemizole ( K i = 20 nM), and inhibition was mostly competitive. Danazol inhibited CYP2C9, CYP2C8, and CYP2D6 with IC50 values of 1.44, 1.95, and 2.74 μM, respectively. Amiodarone or astemizole were included in a seven-probe cocktail for cytochrome P450 (P450) drug-interaction screening potential, and astemizole demonstrated a better profile because it did not appreciably interact with other P450 probes. Thus, danazol, amiodarone, and astemizole will facilitate the ability to determine the metabolic role of CYP2J2 in hepatic and extrahepatic tissues.
CYP2J2 是一种花生四烯酸环氧化酶,它在阿司咪唑和依巴斯汀的首过代谢中的作用已得到公认。要全面评估 CYP2J2 在药物代谢中的作用,必须有选择性底物和强效特异性化学抑制剂。在这项研究中,我们报告了胺碘酮 4-羟基化反应,这是一种由 CYP2J2 催化的特异性反应,没有 CYP3A4 或其他药物代谢酶的参与。通过胺碘酮 4-羟化反应,可以确定 CYP2J2 的肝脏相对活性因子和系统间外推因子。胺碘酮 4-羟基化与阿司咪唑 O-脱甲基化相关,但与人体肝脏微粒体样本中 CYP2J2 蛋白含量无关。为了确定特异性 CYP2J2 抑制剂,研究人员使用特非那定和阿司咪唑作为重组 CYP2J2 的探针底物,对 138 种药物进行了筛选。42 种药物在 30 μM 的浓度下对 CYP2J2 活性的抑制率≥50%,但抑制作用依赖于底物。其中,达那唑是特非那定羟基化(IC50 = 77 nM)和阿司咪唑 O-去甲基化(K i = 20 nM)的强效抑制剂,抑制作用主要是竞争性的。达那唑抑制 CYP2C9、CYP2C8 和 CYP2D6 的 IC50 值分别为 1.44、1.95 和 2.74 μM。胺碘酮或阿司咪唑被纳入七种探针鸡尾酒中进行细胞色素 P450(P450)药物相互作用潜力筛选,阿司咪唑显示出更好的特征,因为它与其他 P450 探针没有明显的相互作用。因此,达那唑、胺碘酮和阿司咪唑将有助于确定 CYP2J2 在肝脏和肝外组织中的代谢作用。