Nuclear Targeting of Cyclin-Dependent Kinase 2 Reveals Essential Roles of Cyclin-Dependent Kinase 2 Localization and Cyclin E in Vitamin D-Mediated Growth Inhibition
Nuclear Targeting of Cyclin-Dependent Kinase 2 Reveals Essential Roles of Cyclin-Dependent Kinase 2 Localization and Cyclin E in Vitamin D-Mediated Growth Inhibition
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DOI：
10.1210/en.2009-1116
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发表时间：
2010-03-01
期刊：
影响因子：
4.8
通讯作者：
Burnstein, Kerry L.
中科院分区：
文献类型：
--
作者：
Flores, Omar;Wang, Zhengying;Burnstein, Kerry L.
1，25-二羟基维生素D-3（1，25-（OH）（2）D-3）抑制多种细胞类型的增殖，包括前列腺腺癌。我们先前已经表明，1，25-（OH）（2）D-3增加了细胞周期蛋白依赖性激酶抑制剂p27（KIP 1）的稳定性，降低了细胞周期蛋白依赖性激酶2（CDK 2）的活性，并促进了人前列腺癌细胞中G（1）期的积累。这些作用与CDK 2的细胞质再定位相关。在这项研究中，我们研究了CDK 2细胞质重定位在1，25-（OH）（2）D-3抗增殖作用中的作用。发现CDK 2对于前列腺癌细胞增殖是必需的。尽管1，25-（OH）（2）D-3对细胞周期蛋白依赖性激酶抑制剂p27（KIP 1）有诱导作用，但它对1，25-（OH）（2）D-3介导的生长抑制作用不明显。1，25-（OH）（2）D-3导致的CDK 2活性降低与T160磷酸化降低相关，T160是一种在细胞核中磷酸化对CDK 2活性至关重要的残基。细胞周期蛋白E的异位表达足以克服1，25-（OH）（2）D-3介导的CDK 2细胞质错误定位和1，25-（OH）（2）D-3的所有抗增殖作用，但内源性细胞周期蛋白E水平或与CDK 2的结合不受1，25-（OH）（2）D-3的影响。类似地，CDK 2底物视网膜母细胞瘤的敲低导致细胞周期蛋白E上调，导致对1，25-（OH）（2）D-3介导的生长抑制的抗性。人前列腺癌细胞对1，25-（OH）（2）D-3的生长抑制具有抗性，但保留了功能齐全的维生素D受体。这些细胞没有表现出1，25-（OH）（2）D-3介导的CDK 2细胞质重定位。将CDK 2靶向1，25-（OH）（2）D-3敏感性癌细胞的细胞核阻断了G（1）的积累和1，25-（OH）（2）D-3的生长抑制。这些数据确立了CDK 2核质运输和细胞周期蛋白E在1，25-（OH）（2）D-3介导的前列腺癌细胞生长抑制机制中的核心作用。（内分泌学151：896-908，2010）
1,25-Dihydroxyvitamin D-3 (1,25-(OH)(2)D-3), inhibits proliferation of a variety of cell types including adenocarcinoma of the prostate. We have previously shown that 1,25-(OH)(2)D-3 increases the stability of the cyclin-dependent kinase inhibitor p27(KIP1), decreases cyclin-dependent kinase 2 (CDK2) activity, and promotes G(1) phase accumulation in human prostate cancer cells. These effects correlate with cytoplasmic relocalization of CDK2. In this study, we investigated the role of CDK2 cytoplasmic relocalization in the antiproliferative effects of 1,25-(OH)(2)D-3. CDK2 was found to be necessary for prostate cancer cell proliferation. Although induced by 1,25-(OH)(2)D-3, the cyclin-dependent kinase inhibitor p27(KIP1) was dispensable for 1,25-(OH)(2)D-3-mediated growth inhibition. Reduction in CDK2 activity by 1,25-(OH)(2)D-3 was associated with decreased T160 phosphorylation, a residue whose phosphorylation in the nucleus is essential for CDK2 activity. Ectopic expression of cyclin E was sufficient to overcome 1,25-(OH)(2)D-3-mediated cytoplasmic mislocalization of CDK2 and all antiproliferative effects of 1,25-(OH)(2)D-3, yet endogenous levels of cyclin E or binding to CDK2 were not affected by 1,25-(OH)(2)D-3. Similarly, knockdown of the CDK2 substrate retinoblastoma, which causes cyclin E up-regulation, resulted in resistance to 1,25-(OH)(2)D-3-mediated growth inhibition. Human prostate cancer cells resistant to growth inhibition by 1,25-(OH)(2)D-3 but retaining fully functional vitamin D receptors were developed. These cells did not exhibit 1,25-(OH)(2)D-3-mediated cytoplasmic relocalization of CDK2. Targeting CDK2 to the nucleus of 1,25-(OH)(2)D-3-sensitive cancer cells blocked G(1) accumulation and growth inhibition by 1,25-(OH)(2)D-3. These data establish central roles for CDK2 nuclear-cytoplasmic trafficking and cyclin E in the mechanism of 1,25-(OH)(2)D-3-mediated growth inhibition in prostate cancer cells. (Endocrinology 151: 896-908, 2010)