Estrogen-induced c-fos protooncogene expression in MCF-7 human breast cancer cells: role of estrogen receptor Sp1 complex formation.
Estrogen-induced c-fos protooncogene expression in MCF-7 human breast cancer cells: role of estrogen receptor Sp1 complex formation.
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DOI：
10.1210/endo.139.4.5870
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发表时间：
1998-04
期刊：
影响因子：
4.8
通讯作者：
R. Duan;Weston Porter;S. Safe
中科院分区：
文献类型：
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作者：
R. Duan;Weston Porter;S. Safe
17β-雌二醇 (E2) 在 MCF-7 人乳腺癌细胞中诱导 c-fos 原癌基因表达，之前在 HeLa 细胞中的研究发现了反式激活所需的不完美回文雌激素响应元件（-1212 至 -1200）。相比之下，MCF-7 细胞中的 E2 响应不需要雌激素响应元件，并且在瞬时转染测定中使用一系列包含野生型 (pF1) 和来自 c-fos 原癌基因启动子的突变 5' 侧翼序列 (-1220 至 -1155) 的构建体，结果表明，富含 GC 的基序 (5'-GGGGCGTGG) 含有 激素诱导的活性需要不完善的 Sp1 结合位点。该序列还在凝胶迁移率变化测定中结合了 Sp1 蛋白，并且与雌激素受体 (ER) 共孵育增强了 Sp1-DNA 结合。 E2 和 4'-羟基他莫昔芬（但不是 ICI 164,384）在用 pF1 瞬时转染的细胞中诱导报告基因活性。 E2 在用 pF1 和野生型 ER 或 DNA 结合域被删除的变体 ER 瞬时共转染的 MDA-MB-231 乳腺癌细胞中诱导报告基因活性 (HE11)；分别表达含有激活子功能-1或-2的ER N端或C端结构域的质粒在这些测定中是无活性的。相反，只有野生型 ER 介导 4'-羟基他莫昔芬诱导的活性。 E2 在 MCF-7 细胞中诱导 c-fos 原癌基因表达依赖于与富含 GC 的增强子元件结合的转录活性 ER/Sp1 复合物的形成。
17Beta-estradiol (E2) induces c-fos protooncogene expression in MCF-7 human breast cancer cells, and previous studies in HeLa cells identified an imperfect palindromic estrogen-responsive element (-1212 to -1200) that was required for trans-activation. In contrast, the estrogen-responsive element was not required for E2 responsiveness in MCF-7 cells, and using a series of constructs containing wild-type (pF1) and mutant 5'-flanking sequences (-1220 to -1155) from the c-fos protooncogene promoter in transient transfection assays, it was shown that a GC-rich motif (5'-GGGGCGTGG) containing an imperfect Sp1-binding site was required for hormone-induced activity. This sequence also bound Sp1 protein in gel mobility shift assays, and coincubation with the estrogen receptor (ER) enhanced Sp1-DNA binding. E2 and 4'-hydroxytamoxifen, but not ICI 164,384, induced reporter gene activity in cells transiently transfected with pF1. E2 induced reporter gene activity in MDA-MB-231 breast cancer cells transiently cotransfected with pF1 and wild-type ER or variant ER in which the DNA-binding domain was deleted (HE11); plasmids expressing N-terminal or C-terminal domains of the ER containing activator function-1 or -2, respectively, were inactive in these assays. In contrast, only wild-type ER mediated 4'-hydroxytamoxifen-induced activity. Induction of c-fos protooncogene expression by E2 in MCF-7 cells is dependent on the formation of a transcriptionally active ER/Sp1 complex that binds to a GC-rich enhancer element.