Estrogen action via the G protein-coupled receptor, GPR30: Stimulation of adenylyl cyclase and cAMP-mediated attenuation of the epidermal growth factor receptor-to-MAPK signaling axis
Estrogen action via the G protein-coupled receptor, GPR30: Stimulation of adenylyl cyclase and cAMP-mediated attenuation of the epidermal growth factor receptor-to-MAPK signaling axis
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DOI：
10.1210/me.16.1.70
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发表时间：
2002-01-01
影响因子：
--
通讯作者：
Bland, KI
中科院分区：
文献类型：
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作者：
Filardo, EJ;Quinn, JA;Bland, KI
雌激素可快速而短暂地激活MAPKs、细胞外信号调节激酶(ERK)-1和ERK-2。我们已经报道，这种雌激素作用需要G蛋白偶联受体GPR30，并通过Gβ-伽玛亚单位蛋白依赖的反式激活表皮生长因子(EGF)受体，通过从细胞表面释放前肝素结合的EGF来实现。在这里，我们研究了雌激素刺激后ERK1/-2活性迅速恢复到基础水平的机制。有证据表明，雌激素对ERK-1/-2活性的抑制是通过GPR30依赖的腺苷环化酶的刺激和cAMP依赖的信号导致Raf-1失活来实现的。我们发现17β-E2抑制EGF诱导的Raf-to-Erk通路在表达GPR30的人乳腺癌细胞中的激活，包括分别表达或不表达ER的MCF-7和SKBR3细胞。表达ERP而不表达ERα的MDA-MB-231细胞和低水平的GPR30蛋白，不能激活腺苷酸环化酶，也不能促进雌激素介导的阻断EGF诱导的Erk-1/-2的激活。用霍乱毒素预处理MDA-MB-231细胞，ADP-核糖化并激活Gas亚单位蛋白，导致G蛋白偶联受体(GPCR)非依赖的腺酰环化酶活性，并抑制EGF诱导的Erk-1/-2活性。将GPR30导入MDA-MB-231细胞，可恢复其激活腺苷酸环化酶的能力，并减弱雌激素对EGF诱导的ERK1/-2的激活。此外，ER拮抗剂如他莫昔芬或ICI182,780可通过GPR30依赖、cAMP介导的方式减弱EGF诱导的ERK1/-2活性，但不能被17α-E2或孕酮所实现。因此，我们的数据描绘了一种需要GPR30和雌激素的新机制，它通过cAMP介导的抑制信号来调节Erk-1/-2的活性。结合我们先前的发现，这些目前的数据表明，雌激素通过两条截然不同的G蛋白依赖的信号通路，通过一次GPCR来平衡Erk-1/-2的活性，这两条信号通路对EGF受体到MAPK的通路具有相反的影响。
Estrogen triggers rapid yet transient activation of the MAPKs, extracellular signal-regulated kinase (Erk)-1 and Erk-2. We have reported that this estrogen action requires the G protein-coupled receptor, GPR30, and occurs via G beta gamma -subunit protein-dependent transactivation of the epidermal growth factor (EGF) receptor through the release of pro-heparan-bound EGF from the cell surface. Here we investigate the mechanism by which Erk1/-2 activity is rapidly restored to basal levels after estrogen stimulation. Evidence is provided that attenuation of Erk-1/-2 activity by estrogen occurs via GPR30-dependent stimulation of adenylyl cyclase and cAMP-dependent signaling that results in Raf-1 inactivation. We show that 17 beta -E2 represses EGF-induced activation of the Raf-to-Erk pathway in human breast carcinoma cells that express GPR30, including MCF-7 and SKBR3 cells which express both or neither, ER, respectively. MDA-MB-231 cells, which express ERP, but not ER alpha, and low levels of GPR30 protein, are unable to stimulate adenylyl cyclase or promote estrogen- mediated blockade of EGF-induced activation of Erk-1/-2. Pretreatment of MDA-MB-231 cells with cholera toxin, which ADP-ribosylates and activates Gas subunit proteins, results in G protein-coupled receptor (GPCR)-independent adenylyl cyclase activity and suppression of EGF-induced Erk-1/-2 activity. Transfection of GPR30 into MDA-MB-231 cells restores their ability to stimulate adenylyl cyclase and attenuate EGF-induced activation of Erk1/-2 by estrogen. Moreover, GPR30-dependent, cAMP-mediated attenuation of EGF-induced Erk1/-2 activity was achieved by ER antagonists such as tamoxifen or ICI 182, 780; yet not by 17 alpha -E2 or progesterone. Thus, our data delineate a novel mechanism, requiring GPR30 and estrogen, that acts to regulate Erk-1/-2 activity via an inhibitory signal mediated by cAMP. Coupled with our prior findings, these current data imply that estrogen balances Erk-1/-2 activity through a single GPCR via two distinct G protein-dependent signaling pathways that have opposing effects on the EGF receptor-to-MAPK pathway.