The gep proto-oncogene Gα12 mediates LPA-stimulated activation of CREB in ovarian cancer cells
The gep proto-oncogene Gα12 mediates LPA-stimulated activation of CREB in ovarian cancer cells
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DOI：
10.1016/j.cellsig.2013.08.012
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发表时间：
2014-01-01
影响因子：
4.8
通讯作者：
Dhanasekaran, Danny N.
中科院分区：
文献类型：
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作者：
Ha, Ji Hee;Ward, Jeremy D.;Dhanasekaran, Danny N.
溶血磷脂酸（LPA）在卵巢癌的病理生理学中起着关键作用。先前的研究表明，LPA通过G α刺激卵巢癌细胞的增殖（12）。本研究利用LPA刺激的HeyA 8细胞的蛋白质/DNA阵列分析，其中G α（12）的表达被沉默，首次证明LPA的G α（12）依赖性促有丝分裂信号传导涉及非典型活化cAMP反应元件结合蛋白（CREB）。结果表明，LPA对CREB的强烈激活是一个早期事件，可以通过CREB的SER 133磷酸化监测，早在3分钟。即使在多个卵巢癌细胞系中没有LPA的情况下，G α（12）的组成型激活突变体的表达也会刺激CREB，这一发现证实了G α（12）在CREB激活中的直接作用。这进一步通过Gan的沉默显著减弱LPA刺激的CREB磷酸化的观察得到证实。我们的研究结果还证实，CREB的LPA-Gceu依赖性激活是通过cAMP非依赖性，但Ras-ERK依赖性机制。更重要的是，我们的研究结果表明，CREB的显性负性S133 A突变体的表达导致LPA刺激的HeyA 8卵巢癌细胞增殖的减少。因此，本研究结果首次证明CREB是卵巢癌细胞中LPA-LPAR和G α（12）/gep原癌基因刺激的致癌信号传导中的关键信号传导节点。(C)版权所有© 2013 Elsevier Inc.
Lysophosphatidic acid (LPA) plays a critical role in the pathophysiology of ovarian cancers. Previous studies have shown that LPA stimulates the proliferation of ovarian cancer cells via G alpha(12). The present study utilizing Protein/DNA array analyses of LPA-stimulated HeyA8 cells in which the expression of G alpha(12) was silenced, demonstrates for the first time that G alpha(12)-dependent mitogenic signaling by LPA involves the atypical activation cAMPresponse element binding protein (CREB). Results indicate that the robust activation of CREB by LPA is an early event that can be monitored by the phosphorylation of SER133 of CREB as early as 3 min. The findings that the expression of the constitutively activated mutant of G alpha(12) stimulates CREB even in the absence of LPA in multiple ovarian cancer cell lines confirm the direct role of G alpha(12) in the activation of CREB. This is further substantiated by the observation that the silencing of Gan drastically attenuates LPA-stimulated phosphowlation of CREB. Our results also establish that LPA-Gceu-dependent activation of CREB is through a cAMP-independent but Ras-ERKdependent mechanism. More significantly, our findings indicate that the expression of the dominant negative S133A mutant of CREB leads to a reduction in LPA-stimulated proliferation of HeyA8 ovarian cancer cells. Thus, results presented here,demonstrate for the first time that CREB is a critical signaling node in LPA-LPAR and G alpha(12)/gep proto-oncogene stimulated oncogenic signaling in ovarian cancer cells. (C) 2013 Elsevier Inc All rights reserved.