Expression of the RET proto-oncogene is regulated by TFAP2C in breast cancer independent of the estrogen receptor.
Expression of the RET proto-oncogene is regulated by TFAP2C in breast cancer independent of the estrogen receptor.
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DOI：
10.1245/s10434-012-2570-5
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发表时间：
2013-07
影响因子：
3.7
通讯作者：
Weigel RJ
中科院分区：
文献类型：
--
作者：
Spanheimer PM;Woodfield GW;Cyr AR;Kulak MV;White-Baer LS;Bair TB;Weigel RJ
RET原癌基因在乳腺癌中作为雌激素受体(ER)簇的一部分表达。我们试图确定Tfap2c是否直接或间接通过ER调节Ret的表达。用染色质免疫沉淀测序(ChIP-Seq)和凝胶移位实验鉴定了四种乳腺癌细胞系中RET启动子中的Tfap2c结合位点。检测Tfap2c基因敲除后ER阳性和ER阴性乳腺癌细胞株中RET的mRNA和蛋白水平。荧光素酶表达分析用于评估其中两个已鉴定位点的表达。ChIP-Seq在Ret转录起始点的−101.5 kb、−50.7 kb、−32.5 kb、+5.0kb和+33.6处发现了Tfap2c的5个主要结合峰。在所有四个细胞系中，AP-2的三个位点的结合是保守的，而在一个细胞系中发现Ret−101.5和Ret+33.6位点均未被Tfap2c结合。所有五个地点都确认了Tfap2c共识要素。在ER阳性的MCF-7细胞中，siRNA下调Tfap2c导致Ret mRNA的表达显著低于非靶向(NT)siRNA(0.09vs.1.0，P<；0.001)。与NT siRNA相比，ER阴性的MDA-MB-453细胞中Tfap2c的敲除也导致Ret mRNA的显著减少(0.16vs.1.0，P<；0.001)。在MCF7细胞中，在ER降低之前，Tfap2c的敲除使Ret蛋白的表达减少(0.02vs.1.0，P<；0.001)。Tfap2c通过RET启动子上的5个AP-2调控位点调控RET原癌基因的表达。在乳腺癌中，Tfap2c对Ret的调节独立于ER的表达。
The RET proto-oncogene is expressed as part of the estrogen receptor (ER) cluster in breast cancer. We sought to determine if TFAP2C regulates Ret expression directly or indirectly through ER. Chromatin immunoprecipitation sequencing (ChIP-Seq) and gel-shift assay were used to identify TFAP2C binding sites in the RET promoter in four breast cancer cell lines. Ret mRNA and protein levels were evaluated in ER-positive and ER-negative breast cancer cell lines after knockdown of TFAP2C. Luciferase expression assay was performed to assess expression from two of the identified sites. ChIP-Seq identified five main binding peaks for TFAP2C in the RET promoter at −101.5 kb, −50.7 kb, −32.5 kb, +5.0 kb, and +33.6 from the RET transcriptional start site. Binding at three of the AP-2 sites was conserved across all four cell lines, whereas the RET −101.5 and RET +33.6 sites were each found to be unbound by TFAP2C in one cell line. A TFAP2C consensus element was confirmed for all five sites. Knockdown of TFAP2C by siRNA in ER-positive MCF-7 cells resulted in significant down regulation of Ret mRNA compared to nontargeting (NT) siRNA (0.09 vs. 1.0, P < 0.001). Knockdown of TFAP2C in ER-negative MDA-MB-453 cells also led to a significant reduction in Ret mRNA compared to NT siRNA (0.16 vs. 1.0, P < 0.001). In MCF-7 cells, knockdown of TFAP2C abrogated Ret protein expression (0.02 vs. 1.0, P < 0.001) before reduction in ER. TFAP2C regulates expression of the RET proto-oncogene through five AP-2 regulatory sites in the RET promoter. Regulation of Ret by TFAP2C occurs independently of ER expression in breast carcinoma.
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影响因子：
3.7
作者：
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通讯作者：
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