Expression of MRP1 and GSTP1-1 modulate the acute cellular response to treatment with the chemopreventive isothiocyanate, sulforaphane.
Expression of MRP1 and GSTP1-1 modulate the acute cellular response to treatment with the chemopreventive isothiocyanate, sulforaphane.
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MRP1 和 GSTP1-1 的表达调节细胞对化学预防性异硫氰酸盐、萝卜硫素治疗的急性反应。
DOI：
10.1093/carcin/bgn013
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发表时间：
2008
期刊：
影响因子：
4.7
通讯作者：
Morrow,CharlesS
中科院分区：
文献类型：
--
作者：
Sibhatu,MebrahtuB;Smitherman,PamelaK;Townsend,AlanJ;Morrow,CharlesS
膳食化学预防剂萝卜硫素（SFN）的抗癌活性的主要成分归因于其诱导在其启动子内含有抗氧化反应元件（ARE）的II期解毒基因的表达的能力。由于SFN是一种反应性亲电体--容易与谷胱甘肽（GSH）形成结合物--我们询问谷胱甘肽S-转移酶（GST）P1-1和GSH结合物外排泵、多药耐药或耐药相关蛋白（MRP）1的表达是否会显著改变细胞对SFN暴露的反应。使用GST-和MRP 1-穷人亲本MCF 7细胞和表达GST 1 -1和/或MRP 1的转基因衍生物进行了研究。与亲本细胞相比，单独表达GSTP 1 -1增强了SFN及其谷胱甘肽结合物SFN-SG的细胞内积累速率-这种效应与增加的ARE-报告基因诱导相关。MRP 1的表达大大降低了SFN/SFN-SG的积累，并导致SFN介导的含ARE的报告基因和内源基因表达的诱导的显著减弱。GST P1 -1与MRP 1的共表达进一步降低了诱导水平。在SFN处理之前先耗尽GSH或用叔丁基对苯二酚替代SFN，则可消除MRP 1/GSTP 1 -1对ARE基因诱导的作用，表明这些作用是GSH依赖的。最后，对NF-E2相关因子2（Nrf 2）--一种通过与ARE结合而起作用的转录因子--的分析表明，SFN处理后Nrf 2水平的增加在MRP 1表达的细胞中，尤其是在共表达GSTP 1 -1的细胞中，比在MRP 1缺乏的细胞中持续时间要短得多。这些结果表明，MRP 1和GST 1 -1表达对SFN依赖的诱导II期基因的调节作用最终是通过改变核Nrf 2水平介导的。
A major component of the anticarcinogenic activity of the dietary chemopreventive agent sulforaphane (SFN) is attributed to its ability to induce expression of phase II detoxification genes containing the antioxidant response element (ARE) within their promoters. Because SFN is a reactive electrophile––readily forming conjugates with glutathione (GSH)––we asked whether expression of glutathioneS-transferase (GST) P1-1 and the GSH conjugate efflux pump, multidrug resistance or resistance-associated protein (MRP) 1, would significantly modify the cellular response to SFN exposure. This was investigated using GST- and MRP1-poor parental MCF7 cells and transgenic derivatives expressing GSTP1-1 and/or MRP1. Compared with parental cells, expression of GSTP1-1 alone enhanced the rate of intracellular accumulation of SFN and its glutathione conjugate, SFN-SG––an effect that was associated with increased ARE-containing reporter gene induction. Expression of MRP1 greatly reduced SFN/SFN-SG accumulation and resulted in significant attenuation of SFN-mediated induction of ARE-containing reporter and endogenous gene expression. Coexpression of GSTP1-1 with MRP1 further reduced the level of induction. Depletion of GSH prior to SFN treatment or the substitution oftert-butylhydroquinone for SFN abolished the effects of MRP1/GSTP1-1 on ARE-containing gene induction—indicating that these effects are GSH dependent. Lastly, analysis of NF-E2-related factor 2 (Nrf2)––a transcription factor operating via binding to the ARE––showed that the increased levels of Nrf2 following SFN treatment were considerably less sustained in MRP1-expressing, especially those coexpressing GSTP1-1, than in MRP1-poor cells. These results suggest that the regulating effects of MRP1 and GSTP1-1 expression on SFN-dependent induction of phase II genes are ultimately mediated by altering nuclear Nrf2 levels.