Estrogen Regulated Expression of the p21Waf1/Cip1 Gene in Estrogen Receptor Positive Human Breast Cancer Cells
Estrogen Regulated Expression of the p21Waf1/Cip1 Gene in Estrogen Receptor Positive Human Breast Cancer Cells
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DOI：
10.1002/jcp.22078
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发表时间：
2010-07-01
影响因子：
5.6
通讯作者：
Davie, James R.
中科院分区：
文献类型：
--
作者：
Mandal, Soma;Davie, James R.
细胞周期蛋白依赖性激酶抑制剂蛋白p21（Waf1/Cip1）是一种有效的肿瘤抑制因子。在这里，我们证明雌二醇调节p21（Waf1/Cip1）基因。在雌激素受体α (ER α)阳性的人乳腺癌细胞系MCF-7中，雌二醇在30-60分钟内诱导p21(Waf1/Cip1) mRNA的表达，与新蛋白的合成无关。与其他雌二醇应答启动子类似，p21（Waf1/Cip1）上游启动子区域有几个雌激素应答元件（ERE）半位点位于Sp1结合位点上游的AP-1结合位点上。通过染色质免疫沉淀（ChIP）实验，我们发现雌二醇刺激导致转录因子ER α， Sp1和Sp3募集到p21（Waf1/Cip1）上游启动子元件。Sp1抑制剂米霉素A抑制Sp1结合，并在较小程度上抑制Sp3结合，显著降低雌二醇刺激的p21（Waf1/Cip1）基因表达。然而，在米霉素A和雌二醇处理的细胞中，内质网α结合不受影响。在另一项ChIP实验中，对Sp1位点上游的半位点ERE/AP-1位点进行了更仔细的检查，我们发现雌激素受体α与雌二醇治疗有明显的关联，而Sp1或Sp3的结合几乎可以忽略不计。总之，这些研究提供了证据，证明ER α被招募到p21（Waf1/Cip1）上游启动子元件的半位点ERE/AP-1位点。虽然Sp1/Sp3不参与ER α向启动子的募集，但Sp1对于雌激素诱导的p21（Waf1/Cip1）启动子活性是必需的。j .细胞。中国生物医学工程学报，2011,31(2):481 - 481。(C) 2010 Wiley-Liss, Inc。
The cyclin-dependent kinase inhibitor protein p21(Waf1/Cip1) is a potent tumor suppressor. Here, we demonstrate that estradiol regulates the p21(Waf1/Cip1) gene. Estradiol induces p21(Waf1/Cip1) mRNA expression within 30-60 min independent of new protein synthesis in the estrogen receptor alpha (ER alpha) positive human breast cancer cell line MCF-7. Similar to other estradiol responsive promoters, the p21(Waf1/Cip1) upstream promoter region has several estrogen response element (ERE) half-sites nestled in AP-1 binding sites, which are positioned upstream to Sp1 binding sites. Using the chromatin immunoprecipitation (ChIP) assay, we show that estradiol stimulation resulted in the recruitment of transcription factors ER alpha, Sp1, and Sp3 to the p21(Waf1/Cip1) upstream promoter element. The Sp1 inhibitor mithramycin A abrogated Sp1, and to a lesser extent Sp3 binding, and markedly reduced the estradiol stimulated p21(Waf1/Cip1) gene expression. However, ER alpha binding was not affected in the mithramycin A and estradiol treated cells. On closer examination of the half-site ERE/AP-1 sites upstream to the Sp1 sites in a separate ChIP experiment, we found a pronounced association of ER alpha upon estradiol treatment compared to almost negligible binding of Sp1 or Sp3. Together these studies provide evidence that ER alpha is recruited to the half-site ERE/AP-1 sites in the p21(Waf1/Cip1) upstream promoter element. Although Sp1/Sp3 is not involved in the recruitment of ER alpha to the promoter, Sp1 is necessary for estrogen-induced p21(Waf1/Cip1) promoter activity. J. Cell. Physiol. 224: 28-32,2010. (C) 2010 Wiley-Liss, Inc.