Monolayer versus aggregate balance in survival process for EGF-induced apoptosis in A431 carcinoma cells: Implication of ROS-P38 mapk-integrin A2B1 pathway
Monolayer versus aggregate balance in survival process for EGF-induced apoptosis in A431 carcinoma cells: Implication of ROS-P38 mapk-integrin A2B1 pathway
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DOI：
10.1002/ijc.20198
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发表时间：
2004-07-20
影响因子：
6.4
通讯作者：
Penel, C
中科院分区：
文献类型：
--
作者：
Morazzani, M;De Carvalho, DD;Penel, C
A431细胞通过形成细胞聚集逃避egf诱导的凋亡。我们发现这些集群迁移并与邻近的集群合并，形成由多层中心（3D）人口组成的更大的结构，周围是单层细胞（2D）。我们发现，在10 nM EGF处理48小时后，3D结构形成与α 2 β 1整合素上调相关。阻断α 2整合素会损害三维结构的形成。我们研究了活性氧（ROS）在这一过程中的作用。我们发现A431细胞表达NADPH氧化酶催化亚基Nox1。在这些细胞中，NADPH氧化酶抑制剂二苯碘（DPI）可以抑制egf诱导的剂量依赖性ROS生成，而鱼藤酮则无效。DPI或ebselen（谷胱甘肽过氧酶模拟物）抑制A431细胞中的ROS水平以及SB203580抑制P38 MAP激酶可降低alpha2整合素亚基表达，诱导向3D而非2D群体转移。2D细胞周期分析显示，DPI、ebselen和SB203580均能减少S/G2期细胞数量，但不影响有丝分裂期细胞数量。相反，对于3D细胞，这些处理增加了有丝分裂细胞的比例，而没有改变SIG2期的细胞数量。DPI和依布selen均能增加两组细胞的凋亡。紫杉醇对细胞聚集体细胞死亡的抗性通常被描述。我们发现DPI可以消除三维细胞聚集体的紫杉醇抗性。我们观察到紫杉醇和DPI之间的加性效应更大，导致3D群体中处于S/G2期的细胞比例增加。这些结果表明ROS-P38 MAP激酶- α 2 β 1整合素通路通过调节2D/3D细胞之间的平衡参与A431存活过程。(C) 2004 Wiley-Liss, Inc。
A431 cells escape EGF-induced apoptosis by forming cell aggregates. We show that these clusters migrate and merge with neighboring ones, resulting in larger structures composed of a multilayer central (3D) population surrounded by a cell monolayer (2D). We found that after 48 hr of 10 nM EGF treatment, 3D structure formation correlates with alpha2beta1 integrin upregulation. Blockade of alpha2 integrin impairs 3D structure formation. We studied the involvement of reactive oxygen species (ROS) in this process. We show that A431 cells express the NADPH oxidase catalytic subunits Nox1. EGF-induced dose-dependant ROS production was inhibited by the NADPH oxidase inhibitor, diphenylene iodonium (DPI), in these cells while rotenone was ineffective. Inhibition of ROS level in A431 cells with DPI or ebselen (glutathione peroxydase mimic) as well as P38 MAP kinase inhibition by SB203580 decreases alpha2 integrin subunit expression and induces a shift to 3D versus 2D populations. Cell cycle analysis of 2D cells shows that DPI, ebselen and SB203580 decrease the number of cells in S/G2 phase without affecting the cell number in mitosis phase. On the contrary, for 3D cells, these treatments increased the proportion of cells in mitosis without modification of the cell number in SIG2 phase. For both populations, apoptosis was increased by DPI and ebselen. Resistance of cell aggregates by paclitaxel to cell death is usually described. We show that DPI abolishes paclitaxel resistance of 3D cell aggregates. We observed a greater than additive effect between paclitaxel and DPI resulting in an increased proportion of cells in S/G2 phase for 3D populations. These results suggested that the ROS-P38 MAP kinase-alpha2beta1integrin pathway was implicated in the A431 survival process by modulating the balance between 2D/3D cells. (C) 2004 Wiley-Liss, Inc.