Alexandrova Antonina Y, Kopnin Pavel B, Vasiliev Jury M, Kopnin Boris P
Institute of Carcinogenesis, Blokhin Memorial Russian Cancer Research Center, Kashirskoye shosse 24, 115478 Moscow, Russia.
Exp Cell Res. 2006 Jul 1;312(11):2066-73. doi: 10.1016/j.yexcr.2006.03.004. Epub 2006 Apr 19.
Expression of activated Ras causes an increase in intracellular content of reactive oxygen species (ROS). To determine the role of ROS up-regulation in mediation of Ras-induced morphological transformation and increased cell motility, we studied the effects of hydrogen peroxide and antioxidant NAC on morphology of REF52 rat fibroblasts and their ability to migrate into the wound in vitro. Treatment with low dosages of hydrogen peroxide leading to 1.5- to 2-fold increase in intracellular ROS levels induced changes of cell shape, actin cytoskeleton organization, cell adhesions and migration resembling those in Ras-transformed cells. On the other hand, treatment with NAC attenuating ROS up-regulation in cells with conditional or constitutive expression of activated Ras led to partial reversion of morphological transformation and decreased cell motility. The effect of ROS on cell morphology and motility probably results from modulation of activity of Rac1, Rho, and cofilin proteins playing a key role in regulation of actin dynamics. The obtained data are consistent with the idea that ROS up-regulation mediates two key events in Ras-induced morphological transformation and cell motility: it is responsible for Rac1 activation and is necessary (though insufficient) for realization of Ras-induced cofilin dephosphorylation.
活化的Ras的表达会导致细胞内活性氧（ROS）含量增加。为了确定ROS上调在介导Ras诱导的形态转化和细胞运动性增加中的作用，我们研究了过氧化氢和抗氧化剂NAC对REF52大鼠成纤维细胞形态及其体外迁移到伤口中的能力的影响。用低剂量过氧化氢处理导致细胞内ROS水平增加1.5至2倍，诱导了细胞形状、肌动蛋白细胞骨架组织、细胞粘附和迁移的变化，类似于Ras转化细胞中的变化。另一方面，用NAC处理可减弱具有活化Ras条件性或组成性表达的细胞中的ROS上调，导致形态转化部分逆转并降低细胞运动性。ROS对细胞形态和运动性的影响可能是由于调节了Rac1、Rho和丝切蛋白等在肌动蛋白动力学调节中起关键作用的蛋白质的活性。获得的数据与以下观点一致，即ROS上调介导了Ras诱导的形态转化和细胞运动性中的两个关键事件：它负责Rac1的激活，并且是实现Ras诱导的丝切蛋白去磷酸化所必需的（尽管不充分）。
