Université de Lyon, F-69000 Lyon, France.
Eur J Cell Biol. 2011 Aug;90(8):631-41. doi: 10.1016/j.ejcb.2011.03.002. Epub 2011 May 11.
Despite its frequent inactivation in human breast cancers, the role of p21(Cip1) (p21) in morphological plasticity of normal mammary epithelial cells is still poorly understood. To address this question, we have investigated the consequences of p21 silencing in two-dimensional (2D) morphogenesis of untransformed human mammary epithelial cells. Here we show that p21 inactivation causes a reduction of 2D cell spreading and suppresses focal adhesion. In order to investigate the cytoskeletal modifications associated with this altered morphology, we have analyzed the microtubule dynamics in interphase p21-depleted cells. Our results demonstrate that interphase microtubule dynamic instability is strongly increased by p21 silencing. This alteration correlates with severe microtubule hypoacetylation. Next, we show that these microtubule defects in p21-depleted cells can be reversed by the use of the small molecule tubacin, a specific inhibitor of the α-tubulin deacetylase HDAC6. Tubacin-induced microtubule dynamics decrease also correlates with a partial recovery of cell spreading and focal adhesion in those cells. Collectively, these data indicate that p21 regulates the morphological plasticity of normal mammary epithelial cells by modulating dynamics of key cytoskeletal components.
尽管在人类乳腺癌中经常失活，但 p21(Cip1)（p21）在正常乳腺上皮细胞形态可塑性中的作用仍知之甚少。为了解决这个问题，我们研究了 p21 沉默对未转化的人乳腺上皮细胞二维（2D）形态发生的影响。在这里，我们发现 p21 失活会导致 2D 细胞铺展减少并抑制焦点粘附。为了研究与这种改变的形态相关的细胞骨架修饰，我们分析了有丝分裂期 p21 耗竭细胞中的微管动力学。我们的结果表明，有丝分裂期微管动态不稳定性通过 p21 沉默而强烈增加。这种改变与微管乙酰化严重降低相关。接下来，我们表明，p21 耗竭细胞中的这些微管缺陷可以通过使用小分子 tubacin 来逆转，tubacin 是 α-微管蛋白去乙酰化酶 HDAC6 的特异性抑制剂。在用 tubacin 诱导微管动力学降低时，这些细胞中的细胞铺展和焦点粘附也会部分恢复。总之，这些数据表明 p21 通过调节关键细胞骨架成分的动力学来调节正常乳腺上皮细胞的形态可塑性。
