Interference with 3',5'-cyclic adenosine monophosphate response element binding protein stimulates apoptosis through aberrant cell cycle progression and checkpoint activation.
Interference with 3',5'-cyclic adenosine monophosphate response element binding protein stimulates apoptosis through aberrant cell cycle progression and checkpoint activation.
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DOI：
10.1210/me.2005-0386
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发表时间：
2006-01
影响因子：
--
通讯作者：
Jessica H. Dworet;J. Meinkoth
中科院分区：
文献类型：
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作者：
Jessica H. Dworet;J. Meinkoth
我们以前报道过蛋白激酶A活性是甲状腺细胞存活的重要决定因素。鉴于cAMP反应元件结合蛋白（CREB）在介导蛋白激酶A的转录效应中的重要作用，我们探讨了CREB家族成员的干扰是否会损害甲状腺细胞的存活。表达A-CREB，一种抑制CREB DNA结合活性的显性负性CREB突变体，诱导大鼠甲状腺细胞凋亡。A-CREB抑制了CREE调控的基因表达，但未能改变bcl-2家族成员或凋亡抑制剂的表达。为了阐明CREB功能受损触发细胞凋亡的机制，检测了其对细胞增殖的影响。A-CREB的表达抑制细胞数量的增加，部分原因是细胞周期转运延迟。表达A-CREB的细胞中的ProkS期进展足以激活以Chk-1、组蛋白H2A.X和p53磷酸化为特征的检查点应答。为了确定细胞周期进程是否是凋亡所必需的，研究了p27过表达的影响。p27的过表达阻止了A-CREB表达细胞的细胞周期进程、检查点激活和凋亡。这些数据揭示了一种新的机制，通过这种机制，干扰CREB通过继发于细胞周期延迟的检查点激活来消除细胞存活。这项研究可以解释如何干扰CREB诱导细胞凋亡的前和抗生存基因的表达的变化没有检测到。
We previously reported that protein kinase A activity is an important determinant of thyroid cell survival. Given the important role of cAMP response element binding protein (CREB) in mediating the transcriptional effects of protein kinase A, we explored whether interference with CREB family members impaired thyroid cell survival. Expression of A-CREB, a dominant-negative CREB mutant that inhibits CREB DNA binding activity, induced apoptosis in rat thyroid cells. A-CREB inhibited CRE-regulated gene expression but failed to alter the expression of bcl-2 family members or of well-characterized inhibitors of apoptosis. To elucidate the mechanism through which impaired CREB function triggered apoptosis, its effects on cell proliferation were examined. Expression of A-CREB inhibited cell number increases, in part due to delayed cell cycle transit. Protracted S-phase progression in A-CREB-expressing cells was sufficient to activate a checkpoint response characterized by Chk-1, histone H2A.X, and p53 phosphorylation. To determine whether cell cycle progression was required for apoptosis, the effects of p27 overexpression were investigated. Overexpression of p27 prevented cell cycle progression, checkpoint activation, and apoptosis in A-CREB-expressing cells. These data reveal a novel mechanism through which interference with CREB abrogates cell survival, through checkpoint activation secondary to cell cycle delay. This study may explain how interference with CREB induces apoptosis in cells where alterations in the expression of pro- and anti-survival genes are not detected.