Differential effects of estradiol and its analogs on cyclin D1 and CDK4 expression in estrogen receptor positive MCF-7 and estrogen receptor-transfected MCF-10AEwt5 cells.
Differential effects of estradiol and its analogs on cyclin D1 and CDK4 expression in estrogen receptor positive MCF-7 and estrogen receptor-transfected MCF-10AEwt5 cells.
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DOI：
10.3892/or.5.5.1025
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发表时间：
1998-09
期刊：
影响因子：
4.2
通讯作者：
J. Hong;N. Shah;T. Thomas;M. Gallo;E. Yurkow;T. Thomas
中科院分区：
文献类型：
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作者：
J. Hong;N. Shah;T. Thomas;M. Gallo;E. Yurkow;T. Thomas
雌激素刺激大多数含有雌激素受体(ER)的人类乳腺肿瘤的生长，雌激素受体是介导雌激素功能的蛋白质。在表达内源性ER的细胞和含有转基因ER的细胞中，已发现雌二醇的相反作用。为了了解雌激素结构在与细胞周期调控相关的多种雌激素反应中的作用，我们研究了雌二醇及其类似物对细胞周期进程的影响，以及对ER阳性MCF-7和ER转基因MCF-10AEwt5细胞周期蛋白D1和细胞周期蛋白依赖性蛋白4(CDK4)表达的影响。使用了四个雌二醇的类似物，具有重新定位或删除的羟基。我们的结果表明，雌激素和所有类似物都促进了MCF-7细胞的细胞周期进程。相反，只有雌二醇显著抑制MCF-10AEwt5细胞的细胞周期进程。免疫印迹分析显示，MCF-7细胞周期开始后6h，细胞周期蛋白Cyclin D1的表达水平达到最高水平。诱导细胞周期蛋白D_1作用最差的类似物是3-羟基雌三烯。然而，该类似物在诱导CDK4方面最有效，有助于其促进MCF-7细胞周期的功效。与MCF-7细胞相比，雌二醇及其类似物对MCF-10AEwt5细胞周期蛋白D1的表达水平无明显影响。MCF-7细胞ER的蔗糖梯度沉淀法分析表明，与ER结合的[~3H]-雌二醇的主峰可以被过量10倍的未标记雌二醇或类似物所取代。相反，在从MCF-10AEwt5细胞竞争置换与ER结合的[~3H]-雌二醇方面，几个类似物的效果不如未标记雌二醇。这些结果表明，细胞周期蛋白D1的诱导是雌激素刺激MCF-7细胞生长的重要部分，但它可能不参与抑制MCF-10AEwt5细胞的生长。我们的结果还表明，雌激素化合物与MCF-10AEwt5细胞的ER相互作用，其配体结合亲和力发生了变化，这可能是由于某些共同调节ER功能的转录因子或ER相关蛋白的缺失或功能障碍所致。
Estradiol stimulates the growth of a majority of human breast tumors containing the estrogen receptors (ERs), proteins that mediates estrogen function. Opposing effects of estradiol have been found in cells expressing endogenous ER and those containing a transfected ER. To understand the role of estradiol structure in diverse estrogenic responses related to cell cycle regulation, we evaluated the effects of estradiol and its analogs on cell cycle progression, and the expression of cyclin D1 and the cyclin dependent kinase 4 (CDK4) in ER-positive MCF-7 and ER-transfected MCF-10AEwt5 cells. Four analogs of estradiol, with a re-positioned or a deleted hydroxyl group, were used. Our results show that estradiol and all of the analogs facilitated cell cycle progression of MCF-7 cells. In contrast, only estradiol inhibited the cell cycle progression of MCF-10AEwt5 cells significantly. Western blot analysis revealed that cyclin D1 protein increased to the maximal level by 6 h after the initiation of cell cycle from G1 phase of MCF-7 cells. The least effective analog in inducing cyclin D1 was 3-hydroxyestratriene. However, this analog was most effective at inducing CDK4, contributing to its efficacy in facilitating MCF-7 cell cycle. In contrast to MCF-7 cells, the level of cyclin D1 protein was not influenced significantly by estradiol or its analogs in MCF-10AEwt5 cells. Sucrose gradient sedimentation analysis of ER from MCF-7 cells showed that the major peak of [3H]-estradiol bound to ER could be displaced by a 10-fold excess of unlabelled estradiol or any of the analogs. In contrast, several analogs were less effective than unlabelled estradiol in competitive displacement of [3H]-estradiol bound to ER from MCF-10AEwt5 cells. These data indicate that the induction of cyclin D1 is an important part of the growth stimulatory effects of estrogens in MCF-7 cells, but it may not be involved in growth inhibition of MCF-10AEwt5 cells. Our results also show that estrogenic compounds interact with ER from MCF-10AEwt5 cells with altered ligand binding affinity, possibly due to the absence or dysfunction of certain transcription factors or ER-associated proteins that co-regulate ER function.