Caco-2 intestinal cell differentiation is associated with G1 arrest and suppression of CDK2 and CDK4
Caco-2 intestinal cell differentiation is associated with G1 arrest and suppression of CDK2 and CDK4
复制标题
DOI：
10.1152/ajpcell.1998.275.5.c1193
复制
发表时间：
1998-11-01
影响因子：
5.5
通讯作者：
Evers, BM
中科院分区：
文献类型：
--
作者：
Ding, QM;Ko, TC;Evers, BM
调节肠增殖和分化的细胞机制在很大程度上仍不明确。以前，我们在Caco-2细胞中发现了细胞周期蛋白依赖性激酶（CDK）抑制剂p21（Waf 1/Cip 1）的早期诱导，Caco-2细胞是一种自发分化为小肠表型的人结肠癌细胞系。本研究的目的是评估Caco-2细胞分化相关的细胞周期阻滞时间，并研究CDK失活的机制。Caco-2细胞经历相对的G（1）/S阻滞，并在融合后第3天停止增殖;在融合后第6天观察到终末分化刷状缘酶（蔗糖酶和碱性磷酸酶）的活性增加。细胞周期阻滞与CDK 2和CDK 4活性的抑制有关，这对G（1）/S进展很重要。用去污剂脱氧胆酸盐（DOC）处理CDK免疫复合物导致融合后第3天CDK 2活性恢复，但不恢复CDK 4活性，表明在该时间点存在与细胞周期蛋白/CDK 2复合物结合的抑制性蛋白。p21结合增加（Waf 1/Cip 1）与CDK 2复合物在融合后第3天的表达，提示p21在融合后第3天的表达中具有潜在的作用。（Waf 1/Cip 1）在CDK 2失活中的作用;但是，在此情况下，p21免疫耗竭（Waf 1/Cip 1）表明，p21（Waf 1/Cip 1）仅部分负责融合后第3天CDK 2的抑制细胞周期蛋白E/的减少CDK 2复合物似乎有助于CDK 2失活在粘土6和12后融合。总之，我们的研究结果表明，多种机制有助于CDK抑制Caco-2细胞分化。CDK 2和CDK 4抑制导致G（1）阻滞和在Caco-2细胞分化之前的增殖抑制。
The cellular mechanisms regulating intestinal proliferation and differentiation remain largely undefined. Previously, we showed an early induction of the cyclin-dependent kinase (CDK) inhibitor p21(Waf1/Cip1) in Caco-2 cells, a human colon cancer line that spontaneously differentiates into a small bowel phenotype. The purpose of our present study was to assess the timing of cell cycle arrest in relation to differentiation in Caco-2 cells and to examine the mechanisms responsible for CDK inactivation. Caco-2 cells undergo a relative G(1)/S block and cease to proliferate at day 3 postconfluency; an increase in the activity of terminally differentiated brush-border enzymes (sucrase and alkaline phosphatase) was noted at day 6 postconfluency. Cell cycle block was associated with suppression of both CDK2 and CDK4 activities, which are important for G(1)/S progression. Treatment of the CDK immune complexes with the detergent deoxycholate (DOC) resulted in restoration of CDK2, but not CDK4, activity at day 3 postconfluency, suggesting the presence of inhibitory protein(s) binding to the cyclin/CDK2 complex at this time point. An increased binding of p21(Waf1/Cip1) to CDK2 complexes at day 3 postconfluency was noted, suggesting a potential role for p21(Waf1/Cip1) in CDK2 inactivation; however, immunodepletion of p21(Waf1/Cip1) from Caco-2 protein extracts demonstrated that p21(Waf1/Cip1) is only partially responsible for CDK2 suppression at day 3 postconfluency A decrease in the cyclin E/CDK2 complex appears to contribute to the CDK2 inactivation noted at clays 6 and 12 postconfluency. Taken together, our results suggest that multiple mechanisms contribute to CDK suppression during Caco-2 cell differentiation. inhibition of CDK2 and CDK4 leads to G(1) arrest and inhibition of proliferation that precede Caco-2 cell differentiation.