Control of cyclin D1, p27Kip1, and cell cycle progression in human capillary endothelial cells by cell shape and cytoskeletal tension
Control of cyclin D1, p27Kip1, and cell cycle progression in human capillary endothelial cells by cell shape and cytoskeletal tension
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DOI：
10.1091/mbc.9.11.3179
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发表时间：
1998-11-01
影响因子：
3.3
通讯作者：
Ingber, DE
中科院分区：
文献类型：
--
作者：
Huang, S;Chen, CS;Ingber, DE
细胞外基质（ECM）在血管生成过程中细胞增殖的调节中发挥着重要作用。细胞与 ECM 的粘附是通过细胞表面整合素受体的结合介导的，该受体既激活细胞内信号级联，又介导细胞形状和细胞骨架结构的张力依赖性变化。尽管生长控制领域主要关注早期整合素和生长因子信号传导事件，但最近的研究表明细胞形状可能在细胞周期进程的控制中发挥同样重要的作用。进行研究以确定细胞形状在细胞周期中何时发挥其调节作用，并分析形状依赖性生长控制的分子基础。人毛细血管内皮细胞的形状是通过在微加工基质上培养细胞来控制的，该微加工基质含有 ECM 涂层的粘合剂岛，其形状和尺寸在微米级陈旧物上或涂有规定的 ECM 分子涂层密度的塑料皿上。在含有可溶性生长因子的培养基中被阻止扩散的细胞表现出丝裂原激活激酶 (erk1/erk2) 生长信号通路的正常激活。然而，与扩散细胞相比，这些细胞未能通过 GI 并进入 S 期。细胞周期进展中的这种形状依赖性阻断与胃肠道晚期未能增加细胞周期蛋白 D1 蛋白水平、下调细胞周期抑制剂 p27(kip1) 和磷酸化视网膜母细胞瘤蛋白相关。通过使用细胞松弛素破坏肌动蛋白网络或使用肌动球蛋白相互作用抑制剂抑制细胞骨架张力的产生，在相同的形状敏感限制点之前诱导细胞周期进程的类似阻断。相比之下，细胞形状、细胞骨架结构和机械张力的改变在稍后添加时对进入S期都没有任何影响。这些发现表明，尽管早期生长因子和整合素信号传导事件是生长所必需的，但仅靠它们还不够。随后的细胞周期进展以及细胞增殖是由细胞形状和细胞骨架结构的张力依赖性变化控制的，这些变化通过抑制调节 G1/S 转变的分子机制来发挥作用。
The extracellular matrix (ECM) plays an essential role in the regulation of cell proliferation during angiogenesis. Cell adhesion to ECM is mediated by binding of cell surface integrin receptors, which both activate intracellular signaling cascades and mediate tension-dependent changes in cell shape and cytoskeletal structure. Although the growth control field has focused on early integrin and growth factor signaling events, recent studies suggest that cell shape may play an equally critical role in control of cell cycle progression. Studies were carried out to determine when cell shape exerts its regulatory effects during the cell cycle and to analyze the molecular basis for shape-dependent growth control. The shape of human capillary endothelial cells was controlled by culturing cells on microfabricated substrates containing ECM-coated adhesive islands with defined shape and size on the micrometer stale or on plastic dishes coated with defined ECM molecular coating densities. Cells that were prevented from spreading in medium containing soluble growth factors exhibited normal activation of the mitogen-activated kinase (erk1/erk2) growth signaling pathway. However, in contrast to spread cells, these cells failed to progress through GI and enter S phase. This shape-dependent block in cell cycle progression correlated with a failure to increase cyclin D1 protein levels, down-regulate the cell cycle inhibitor p27(kip1) and phosphorylate the retinoblastoma protein in late GI. A similar block in cell cycle progression was induced before this same shape-sensitive restriction point by disrupting the actin network using cytochalasin or by inhibiting cytoskeletal tension generation using an inhibitor of actomyosin interactions. In contrast, neither modifications of cell shape, cytoskeletal structure, nor mechanical tension had any effect on S phase entry when added at later times. These findings demonstrate that although early growth factor and integrin signaling events are required for growth, they alone are not sufficient. Subsequent cell cycle progression and, hence, cell proliferation are controlled by tension-dependent changes in cell shape and cytoskeletal structure that act by subjugating the molecular machinery that regulates the G1/S transition.