Transcriptional activation of functional endogenous estrogen receptor gene expression in MCF10AT cells: a model for early breast cancer.
Transcriptional activation of functional endogenous estrogen receptor gene expression in MCF10AT cells: a model for early breast cancer.
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DOI：
10.3892/ijo.13.5.907
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发表时间：
1998-11
影响因子：
5.2
通讯作者：
P. Shekhar;M. L. Chen;J. Werdell;G. Heppner;F. Miller;J. Christman
中科院分区：
文献类型：
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作者：
P. Shekhar;M. L. Chen;J. Werdell;G. Heppner;F. Miller;J. Christman
利用MCF 10AT异种移植模型进行人增生性乳腺疾病的进展，我们检测到内源性雌激素受体（ER）基因的表达仅在MCF 10AneoT和MCF 10AT系统的细胞中，所有这些细胞都稳定表达转染的突变T24 Ha-ras基因。在亲本MCF 10A细胞和转染正常c-Ha-ras或载体的MCF 10A细胞中检测不到ER转录本。在MCF 10 AT细胞中表达的ER转录物含有正常全长ER编码区和正常大小的ER蛋白的直接合成。该蛋白是基于其介导雌二醇（E2）诱导的内源性和外源性E2调节基因转录增加的能力的功能。内源性ER基因的转录激活似乎与基因甲基化状态的变化无关，因为ER阴性乳腺肿瘤中甲基化和ER阳性乳腺肿瘤中完全未甲基化的外显子1中的诊断性CpG位点在ER阴性MCF 10A细胞和ER阳性MCF 10AT细胞中甲基化程度相同。E2增加了MCF 10AT 3c细胞形成的软琼脂集落的数量和大小，MCF 10AT 3c细胞是来自第三代MCF 10AT异种移植病变的细胞系。这表明异种移植物传代选择了E2反应性的生长调节途径，并且这些途径及其在进展中的作用的鉴定将有助于确定E2如何增加乳腺癌风险。
Utilizing the MCF10AT xenograft model for progression of human proliferative breast disease, we detected expression of the endogenous estrogen receptor (ER) gene only in MCF10AneoT and cells of the MCF10AT system, all of which stably express a transfected mutated T24 Ha-ras gene. ER transcripts were undetectable in the parental MCF10A cells and in MCF10A cells transfected with normal c-Ha-ras or vector. ER transcripts expressed in MCF10AT cells contain a normal full-length ER coding region and direct synthesis of a normally sized ER protein. The protein is functional based on its ability to mediate estradiol (E2)-induced increases of transcription from both endogenous and exogenous E2-regulated genes. Transcriptional activation of the endogenous ER gene does not appear to be related to a change in methylation status of the gene since a diagnostic CpG site in exon 1 that is methylated in ER-negative breast tumors and completely unmethylated in ER-positive breast tumors is hypomethylated to the same extent in ER-negative MCF10A cells and ER-positive MCF10AT cells. E2 increased both the number and size of soft-agar colonies formed by MCF10AT3c cells, a line from a third generation MCF10AT xenograft lesion. This suggests that xenograft passage has selected for growth regulatory pathways that are E2-responsive and that identification of these pathways and their role in progression will aid in determining how E2 acts to increase risk of breast cancer.