Nuclear and extranuclear pathway inputs in the regulation of global gene expression by estrogen receptors
Nuclear and extranuclear pathway inputs in the regulation of global gene expression by estrogen receptors
复制标题
DOI：
10.1210/me.2008-0059
复制
发表时间：
2008-09-01
影响因子：
--
通讯作者：
Katzenellenbogen, Benita S.
中科院分区：
文献类型：
--
作者：
Madak-Erdogan, Zeynep;Kieser, Karen J.;Katzenellenbogen, Benita S.
虽然雌激素通过与核雌激素受体(ER)结合并直接改变靶基因转录来发挥作用，但它们也可以通过激活激酶级联来启动核外信号转导。我们利用雌激素-树突状分子偶联物(EDCs)研究了雌激素介导的核外启动通路对全球基因表达的影响，由于其电荷和大小保持在核外，只能启动核外信号。对MCF-7乳腺癌细胞进行的全基因组cDNA微阵列分析发现，17个β-雌二醇(E2)调节基因的子集(类似于25%)对EDC有反应。EDC和E2诱导的基因表达增加是由于基因转录的增加，正如在核连续分析和RNA聚合酶II招募和磷酸化中观察到的那样。用抗雌激素或使用小干扰RNA敲除ERα可消除EDC介导的基因刺激，而GPR30敲除或GPR30选择性配体处理则无效，表明ER是这些基因调节的中介。MAPK和c-Src的抑制剂可抑制E_2和EDC刺激的基因表达。值得注意的是，在染色质免疫沉淀分析中，EDC不能将ERα招募到受调控基因的雌激素反应区域，而E2招募ER是非常有效的。这些发现表明，作为EDC启动的核外信号级联反应的下游效应者的其他转录因子或激酶被招募到EDC反应基因的调节区，以诱导基因刺激。因此，这项研究强调了来自核和核外ER信号通路的输入在调节乳腺癌细胞基因表达模式中的重要性。
Whereas estrogens exert their effects by binding to nuclear estrogen receptors (ERs) and directly altering target gene transcription, they can also initiate extranuclear signaling through activation of kinase cascades. We have investigated the impact of estrogen-mediated extranuclear-initiated pathways on global gene expression by using estrogen-dendrimer conjugates (EDCs), which because of their charge and size remain outside the nucleus and can only initiate extranuclear signaling. Genome-wide cDNA microarray analysis of MCF-7 breast cancer cells identified a subset of 17 beta- estradiol (E2)-regulated genes (similar to 25%) as EDC responsive. The EDC and E2-elicited increases in gene expression were due to increases in gene transcription, as observed in nuclear run-on assays and RNA polymerase II recruitment and phosphorylation. Treatment with antiestrogen or ER alpha knockdown using small interfering RNA abolished EDC-mediated gene stimulation, whereas GPR30 knockdown or treatment with a GPR30-selective ligand was without effect, indicating ER as the mediator of these gene regulations. Inhibitors of MAPK kinase and c-Src suppressed both E2 and EDC stimulated gene expression. Of note, in chromatin immunoprecipitation assays, EDC was unable to recruit ER alpha to estrogen-responsive regions of regulated genes, whereas ER recruitment by E2 was very effective. These findings suggest that other transcription factors or kinases that are downstream effectors of EDC-initiated extranuclear signaling cascades are recruited to regulatory regions of EDC-responsive genes in order to elicit gene stimulation. This study thus highlights the importance of inputs from both nuclear and extranuclear ER signaling pathways in regulating patterns of gene expression in breast cancer cells.