Induction of detoxifying enzymes by garlic organosulfur compounds through transcription factor Nrf2: Effect of chemical structure and stress signals
Induction of detoxifying enzymes by garlic organosulfur compounds through transcription factor Nrf2: Effect of chemical structure and stress signals
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DOI：
10.1016/j.freeradbiomed.2004.07.021
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发表时间：
2004-11-15
影响因子：
7.4
通讯作者：
Kong, ANT
中科院分区：
文献类型：
--
作者：
Chen, C;Pung, D;Kong, ANT
大蒜有机硫化合物（OSCs）被认为是一类潜在的化学预防化合物。众所周知，大蒜OSCs可以调节药物代谢系统，特别是各种II期解毒酶，尽管其诱导这些酶的机制仍不清楚。在本研究中，我们研究了三种主要大蒜oscs -二烯丙基硫醚（DAS）、二烯丙基二硫醚（DADS）和二烯丙基三硫醚（DATS）在人肝癌HepG2细胞中NAD(P)H：醌氧化还原酶1 （NQO1）和血红素氧合酶1 （HO1）基因的转录水平、抗氧化反应元件（ARE）介导的报告基因活性以及转录因子核因子e2相关因子2 （Nrf2）的蛋白水平。我们的研究结果表明，ARE激活和Nrf2蛋白积累与II期基因表达诱导密切相关。构效关系研究表明，OSCs结构中的第三个硫对其生物活性有重要贡献，含烯丙基OSCs比含丙基OSCs更有效。为了更好地理解DATS上调解毒酶的信号事件，我们用突变体Nrf2瞬时转染HepG2细胞，与抗氧化剂共处理，并与蛋白激酶抑制剂预处理后，检测了ARE活性和Nrf2蛋白水平。dats诱导的ARE活性被显性阴性Nrf2和kelch样ech相关蛋白1结构体抑制。与巯基抗氧化剂共处理可降低DATS诱导的ARE活性和Nrf2蛋白水平。三种主要的丝裂原活化蛋白激酶(MAPKs)-细胞外信号调节蛋白激酶，c-Jun n-末端激酶和p38-被DATS激活。然而，抑制这些MAPKs并不影响dats诱导的ARE活性。多种上游蛋白激酶抑制剂预处理表明，蛋白激酶C途径不直接参与dats诱导的ARE活性，而钙依赖信号通路似乎在dats诱导的细胞保护作用中起作用。(C) 2004爱思唯尔公司版权所有。
Garlic organosulfur compounds (OSCs) are recognized as a group of potential chemopreventive compounds. It is known that garlic OSCs can modulate drug metabolism systems, especially various phase II detoxifying enzymes, though the mechanism underlying their inductive effect on these enzymes remains largely unknown. In the present study, we investigated the transcriptional levels of NAD(P)H:quinone oxidoreductase 1 (NQO1) and heme oxygenase 1 (HO1) genes, the reporter activity mediated by antioxidant response element (ARE), and the protein level of transcription factor nuclear factor E2-related factor 2 (Nrf2), after administration of three major garlic OSCs-diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS)-in human hepatoma HepG2 cells. Our results showed that ARE activation and Nrf2 protein accumulation were well correlated with phase II gene expression induction. The structure-activity relationship study indicated that the third sulfur in the structure of OSCs contributed substantially to their bioactivities, and that allyl-containing OSCs were more potent than propyl-containing OSCs. To better understand the signaling events involved in the upregulation of detoxifying enzymes by DATS, ARE activity and Nrf2 protein levels were examined after transient transfection of HepG2 cells with mutant Nrf2, cotreatment with antioxidants, and pretreatment with protein kinase inhibitors. DATS-induced ARE activity was inhibited by dominant-negative Nrf2 and Kelch-like ECH-associating protein 1 constructs. Cotreatment with thiol antioxidants decreased the ARE activity and Nrf2 protein level induced by DATS. Three major mitogen-activated protein kinases (MAPKs)-extracellular signal-regulated protein kinase, c-Jun N-terminal kinase, and p38-were activated by DATS treatment. However, the inhibition of these MAPKs did not affect DATS-induced ARE activity. Pretreatment with various upstream protein kinase inhibitors showed that the protein kinase C pathway was not directly involved in DATS-induced ARE activity, but instead the calcium-dependent signaling pathway appeared to play a role in the DATS-induced cytoprotective effect. (C) 2004 Elsevier Inc. All rights reserved.