Ets-1 activates parathyroid hormone-related protein gene expression in tumorigenic breast epithelial cells
Ets-1 activates parathyroid hormone-related protein gene expression in tumorigenic breast epithelial cells
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DOI：
10.1016/s0303-7207(02)00298-8
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发表时间：
2003-06-30
影响因子：
4.1
通讯作者：
Bouizar, Z
中科院分区：
文献类型：
--
作者：
Cataisson, C;Gordon, J;Bouizar, Z
甲状旁腺素相关蛋白（PTHrP）是由许多与体液性高钙血症无关的肿瘤产生的，包括乳腺癌。在这项研究中，我们使用了三个人永生化乳腺上皮细胞系，不同的致瘤性和PTHrP表达。利用RT-PCR技术，我们研究了PTHrP转录本的5'和3'选择性剪接以及启动子在这些品系中的使用。在大多数致瘤细胞系中观察到P3衍生的转录物和1-139 mRNA亚型的水平增加。瞬时转染实验确定了接近P3启动子的元件，这些元件似乎占三种细胞系之间PTHrP表达差异的一部分。使用定点诱变，先前描述的Ets-1/Sp1结合位点上游的P3被确定为是至关重要的，这个启动子的全部活性。RT-PCR和蛋白质印迹评价Ets家族成员的表达发现，Ese-1是存在于所有三个线，但Ets-1蛋白质的可观的水平只存在于最致瘤线。Ets-1表达载体的共转染激活PTHrP报告构建体中的最致瘤性线，但不是在其他细胞系。这些研究结果表明，PTHrP转录可能是一个潜在的机制，调节的结果，促进乳腺上皮细胞的致瘤行为的事件。(C)2002爱思唯尔科学爱尔兰有限公司保留所有权利。
Parathyroid hormone-related protein (PTHrP) is produced by many tumors not associated with humoral hypercalcemia, including breast cancers. In this study, we used three human immortalized mammary epithelial cell lines that differ in tumorigenicity and PTHrP expression. Using RT-PCR we investigated 5' and 3' alternative splicing of PTHrP transcripts and promoter usage in the lines. Increased levels of P3-derived transcripts and the 1-139 mRNA isoform were observed in the most tumorigenic cell line. Transient transfection experiments identified elements close to P3 promoter that appeared to account for a portion of differential PTHrP expression among the three cell lines. Using site-directed mutagenesis, a previously described Ets-1/Sp1 binding site upstream of P3 was determined to be crucial for full activity of this promoter. RT-PCR and western blot evaluation of Ets family member expression found that Ese-1 was present in all three lines, but that appreciable levels of Ets-1 protein were present exclusively in the most tumorigenic line. Cotransfection of Ets-1 expression vectors activated PTHrP reporter constructs in the most tumorigenic line but not in the other cell lines. These findings suggest a potential mechanism by which PTHrP transcription may be regulated as a consequence of events that promote tumorigenic behavior in breast epithelial cells. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.