Expression of ezrin correlates with malignant phenotype of lung cancer, and in vitro knockdown of ezrin reverses the aggressive biological behavior of lung cancer cells
Expression of ezrin correlates with malignant phenotype of lung cancer, and in vitro knockdown of ezrin reverses the aggressive biological behavior of lung cancer cells
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DOI：
10.1007/s13277-012-0400-9
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发表时间：
2012-10-01
期刊：
影响因子：
--
通讯作者：
Wang, Enhua
中科院分区：
文献类型：
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作者：
Li, Qingchang;Gao, Hui;Wang, Enhua
Ezrin是一种Ezrin-Radisin-moesin蛋白，参与细胞膜过程的形成，如片状脂膜和丝状胞壁，并作为膜-细胞骨架连接物。它的异常表达与几种人类癌症的发生发展有关。然而，Ezrin的表达及其在肺癌中的作用目前尚不清楚。在这项研究中，我们进行了ezrin小干扰核糖核酸在两个肺癌细胞系中的转染，并通过3-(4，5-dimethylthiazol-2-yl)-2，5-diphenyltetrazolium溴化试验、伤口愈合试验和小室穿透试验检测了其对癌细胞恶性表型的影响。在体外，Ezrin基因敲除显著减少了肺癌细胞的增殖、迁移和侵袭。为了探讨可能的机制，我们通过Western印迹和逆转录聚合酶链式反应分析了黏附分子E-钙粘素和β-连环蛋白的表达。结果表明，Ezrin的下调在蛋白水平上降低了β-连环素，增加了E-钙粘附素，但对它们的mRNA水平没有影响，提示这两种黏附分子在转录后调节。免疫荧光分析显示，Ezrin基因敲除可恢复肺癌细胞膜上E-钙粘附素的表达，降低胞浆β-连环素的表达。另外，采用免疫组织化学方法检测了135例正常肺组织和183例肺癌组织中Ezrin的表达。Ezrin在癌组织中的表达显著高于配对的自体正常肺组织。在正常支气管上皮中，Ezrin主要分布在顶膜上，而在肺癌和转移灶中，Ezrin主要分布在细胞质中。在肺癌组织中，Ezrin在原发灶的浸润性前沿表达较高，在淋巴转移灶中的表达最高。统计学分析表明，Ezrin的表达与肿瘤的淋巴转移和TNM分期密切相关。我们的数据表明，Ezrin可能在肺癌的生物学行为中发挥关键作用。
Ezrin, one of the ezrin-radixin-moesin proteins, is involved in the formation of cell membrane processes such as lamellipodia and filopodia and acts as a membrane-cytoskeleton linker. Its aberrant expression correlates with development and progression of several human cancers. However, the expression of ezrin and its role in lung cancer are currently unknown. In this study, we performed ezrin small interfering RNA transfection in two lung cancer cell lines and examined the effects on malignant phenotypes in cancer cells by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound healing, and chamber transwell assays. Ezrin knockdown significantly reduced the proliferation, migration, and invasion of lung cancer cells in vitro. To address the possible mechanisms, we evaluated the expression of adhesion molecules E-cadherin and beta-catenin by Western blot and reverse transcriptase-polymerase chain reaction analyses. The results demonstrated that downregulation of ezrin reduced beta-catenin and increased E-cadherin at the protein level but had no effects on their mRNA levels, suggesting posttranscriptional regulation of these two adhesion molecules. Immunofluorescence assays revealed that ezrin knockdown restored membranous expression of E-cadherin and decreased cytoplasmic beta-catenin in lung cancer cells. In addition, ezrin expression was immunohistochemically evaluated on 135 normal and 183 lung cancer tissues. The expression of ezrin was significantly higher in cancer samples than paired autologous normal lung tissues. In normal bronchial epithelium, ezrin was mainly localized on the apical membrane, while in lung cancers and metastatic foci, ezrin was primarily distributed in cytoplasm. Among lung cancer tissues, expression of ezrin was higher in the invasive front of primary lesions and the highest in lymphatic metastasis. Statistical analysis demonstrated that ezrin expression correlated significantly with lymphatic metastasis and advanced TNM stage. Our data suggest that ezrin may play a crucial role in governing the biological behavior of lung cancer.