INDUCTION OF PHASE-I AND PHASE-II DRUG-METABOLIZING ENZYME MESSENGER-RNA, PROTEIN, AND ACTIVITY BY BHA, ETHOXYQUIN, AND OLTIPRAZ
INDUCTION OF PHASE-I AND PHASE-II DRUG-METABOLIZING ENZYME MESSENGER-RNA, PROTEIN, AND ACTIVITY BY BHA, ETHOXYQUIN, AND OLTIPRAZ
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DOI：
10.1006/taap.1995.1207
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发表时间：
1995-11-01
影响因子：
3.8
通讯作者：
EATON, DL
中科院分区：
文献类型：
--
作者：
BUETLER, TM;GALLAGHER, EP;EATON, DL
已知各种天然和合成化合物通过提高II期解毒酶来预防癌症。这些诱导剂通常被归类为无功能的，被认为触发细胞信号，通过响应基因中的抗氧化剂或亲电响应元件（ARE/EpRE）激活基因转录。相反，药物代谢的I相酶（细胞色素P450）不被认为是由单功能诱导剂诱导的，并且尚未发现P450基因含有功能性ARE/EpRE。在本研究中，用单功能诱导剂叔丁基羟基茴香醚、乙氧喹和奥替普拉处理大鼠，以研究单个谷胱甘肽S-转移酶同工酶、NADP（H）：醌氧化还原酶、γ-谷氨酰半胱氨酸合成酶、UDP-葡萄糖醛酸转移酶和细胞色素P450酶的诱导作用。使用GST Ya 1、Ya 2、Yc 1、Yc 2、Yb 1、Yb 2和Yf、UGT 1*06和P450 1A 1、1A 2、2B 1、2C 11、3A 2和4A 1的基因特异性寡核苷酸探针，在北方印迹上分析肝脏mRNA。NADP（H）：醌氧化还原酶和γ-谷氨酰半胱氨酸合成酶mRNA的检测使用cDNA探针。所有的II期解毒酶的分析，除了GST YF，诱导的三个单功能诱导剂，这表明这些基因可能是由一种机制，涉及ARE/EpRE元件在其启动子区进行调节。有趣的是，发现乙氧喹是P450 2B家族的两个成员2B 1和2B 2的特别好的诱导剂，并且乙氧喹和奥替普拉也能够适度诱导P450 1A 2和3A 2。在分析的剂量和时间下，发现奥替普拉轻微诱导P450 2B 2，但不诱导2B 1。mRNA的诱导通常与通过Western印迹和/或所选酶的酶活性测量确定的蛋白质水平的诱导良好相关。这项研究的结果表明，许多第二阶段的酶可能含有ARE/EpRE元素，除了那些被证实是由涉及ARE/EpRE元素的机制进行调节。此外，有人发现，几个P450酶诱导的单功能诱导剂，这表明一种可能性，即一些I相酶也可能是由涉及ARE/EpRE元件的机制进行调节。(C)出版社：Academic Press
Various natural and synthetic compounds are known to protect against cancer by elevating phase II detoxification enzymes. Generally classified as nonfunctioning, these inducers are believed to trigger cellular signal(s) that activate gene transcription through an antioxidant or electrophile response element (ARE/EpRE) in responsive genes. In contrast, the phase I enzymes of drug metabolism (cytochrome P450s) are not believed to be induced by monofunctional inducers and P450 genes have not been found to contain functional ARE/EpREs. In this study, rats were treated with the monofunctional inducers tert-butylated hydroxyanisole, ethoxyquin, and oltipraz to study the inducibility of individual glutathione S-transferase isozymes, NADP(H):quinone oxidoreductase, gamma-glutamylcysteine synthetase, UDP-glucuronosyl transferase, and cytochrome P450 enzymes. Hepatic mRNAs were analyzed on Northern blots using gene-specific oligonucleotide probes for GST Ya1, Ya2, Yc1, Yc2, Yb1, Yb2, and Yf, for UGT 1*06, and for P450 1A1, 1A2, 2B1, 2C11, 3A2, and 4A1. NADP(H):quinone oxidoreductase and gamma-glutamylcysteine synthetase mRNAs were detected using cDNA probes. All the phase II detoxification enzymes analyzed, except GST Yf, were induced by the three monofunctional inducers, suggesting that these genes may be regulated by a mechanism involving an ARE/EpRE element in their promoter region. Interestingly, it was found that ethoxyquin was a particularly good inducer for both members of the P450 2B family, 2B1 and 2B2, and both ethoxyquin and oltipraz were also capable of modestly inducing P450 1A2 and 3A2. Oltipraz was found to slightly induce P450 2B2, but not 2B1, at the dose and time analyzed. Induction of mRNA generally correlated well with induction of protein levels determined by Western blot and/or enzyme activity measurements for selected enzymes. The results of this study suggest that many phase II enzymes may contain ARE/EpRE elements in addition to those confirmed to be regulated by a mechanism involving ARE/EpRE elements. In addition, it was found that several P450 enzymes were induced by monofunctional inducers, suggesting a possibility that some phase I enzymes may also be regulated by a mechanism involving ARE/EpRE elements. (C) 1995 Academic Press, Inc.