Mechanism of cell cycle arrest caused by histone deacetylase inhibitors in human carcinoma cells
Mechanism of cell cycle arrest caused by histone deacetylase inhibitors in human carcinoma cells
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DOI：
10.7164/antibiotics.53.1191
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发表时间：
2000-10-01
影响因子：
3.3
通讯作者：
Horinouchi, S
中科院分区：
文献类型：
--
作者：
Kim, YB;Ki, SW;Horinouchi, S
在许多细胞类型中，组蛋白去乙酰化酶（HDAC）抑制剂阻断G1细胞周期进程。我们研究了trichostatin A (TSA)，一种HDAC特异性抑制剂，在人宫颈癌HeLa细胞中诱导G1阻滞的机制。TSA处理诱导组蛋白高乙酰化，随后在G1期生长停滞以及pRb的低磷酸化。在tsa诱导的G1阻滞期间，Cdk4激酶活性基本不变。另一方面，这种阻滞伴随着Cdk2激酶活性的下调，尽管Cdk2及其激活剂Cdc25A的总蛋白水平不受影响。经TSA处理后，细胞周期蛋白E和CDK抑制剂p21（WAF1/Cip1）的含量明显升高，而细胞周期蛋白A的含量明显降低。p21的诱导和cyclin A的下调与Cdk2活性的降低和细胞周期阻滞密切相关。此外，凝胶过滤层析显示p21与细胞周期蛋白E-Cdk2复合物的关联，表明细胞周期蛋白E表达增强对Cdk2的激活被p21的增加所阻断。在曲曲霉毒素和FR901228（结构无关的组蛋白去乙酰化酶抑制剂）处理的细胞中也观察到p21的表达升高。缺乏p21基因两个等位基因（p21 -/-）的人结直肠癌细胞系对TSA的抗性是亲本细胞系（p21 +/+）的数倍。这些结果表明，由于p21过表达而抑制Cdk2激酶活性在HDAC抑制剂诱导的生长抑制中起关键作用。
Inhibitors of histone deacetylase (HDAC) block cell cycle progression at G1 in many cell types. We investigated the mechanism by which trichostatin A (TSA), a specific inhibitor of HDAC, induces G1 arrest in human cervix carcinoma HeLa cells. TSA treatment induced histone hyperacetylation followed by growth arrest in G1 as well as hypophosphorylation of pRb. The Cdk4 kinase activity was essentially unchanged during the TSA-induced G1 arrest. On the other hand, the arrest was accompanied by down-regulation of kinase activity of Cdk2, although the total protein levels of Cdk2 and its activator Cdc25A were unaffected. Upon TSA treatment, amounts of cyclin E and the CDK inhibitor p21(WAF1/Cip1) were markedly increased, while that of cyclin A was reduced. The induction of p21 and down-regulation of cyclin A correlated well with the decreased Cdk2 activity and cell cycle arrest. Furthermore, gel filtration chromatography showed the association of p21 with the cyclin E-Cdk2 complex, suggesting that the activation of Cdk2 by the enhanced expression of cyclin E is blocked by the increased p21. The elevated expression of p21 is also observed in cells treated with trapoxin and FR901228, structurally unrelated histone deacetylase inhibitors. A human colorectal carcinoma cell line lacking both alleles of the p21 gene (p21 -/-) was resistant to TSA several times more than the parental line (p21 +/+). These results suggest that the suppression of Cdk2 kinase activity due to p21 overexpression play a critical role in HDAC inhibitor-induced growth inhibition.