Overexpression of Rho effector rhotekin confers increased survival in gastric adenocarcinoma
Overexpression of Rho effector rhotekin confers increased survival in gastric adenocarcinoma
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DOI：
10.1159/000079679
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发表时间：
2004-01-01
影响因子：
11
通讯作者：
Chen, JY
中科院分区：
文献类型：
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作者：
Liu, CA;Wang, MJ;Chen, JY
像许多上皮源性癌症一样，胃癌（GC）是一个多步骤的致瘤过程。然而，GC形成的详细机制却没有得到很好的描述。利用有序差分显示法，我们鉴定了Rho效应基因RTKN （rhotekin， RTKN）是人GC中差异表达的基因之一。Northern对人体多组织印迹的分析表明，RTKN主要在肾脏和脊髓中表达，在甲状腺、舌头、肝脏、大脑、前列腺、气管和胃中也有少量表达。RT-PCR分析证实RTKN在大多数GC检测中过表达（5/7;71%）。通过分析Stanford Microarray数据库中胃组织的表达谱，我们还发现RTKN在非肿瘤性粘膜、胃癌和淋巴结转移中的表达呈进行性增加（Jonckheere-Terpstra检验p < 0.005），表明RTKN的表达与胃癌的进展有关。通过在低基础水平表达内源性RTKN的AGS胃细胞中转染和表达RTKN，研究RTKN在胃癌发病过程中的作用。流式细胞术分析显示，经丁酸钠处理后，rtkn转染的AGS细胞对凋亡的抵抗能力明显强于载体转染的细胞。为了探索rtkn介导的细胞存活机制，进行了报告基因实验。由于已知NF-kappa B激活可促进细胞存活，而Rho GTPase可能导致NF-kappa B激活，我们将RTKN表达载体与pNF-kappa B- luc报告质粒一起转染AGS细胞。我们的研究结果表明，RTKN的过表达诱导NF-kappa B的强烈激活，RTKN介导的NF-kappa B激活被C3转移酶（一种小GTPase Rho抑制剂）显著抑制。我们得出结论，Rho/ rtkn介导的NF-kappa B激活导致细胞存活可能在胃肿瘤发生中起关键作用。本研究为Rho GTPase效应物rhotekin在人类癌症中的过度表达及其与癌症形成的联系提供了原始文件。版权所有(C) 2004国家科学委员会，中华民国和S. Karger AG，巴塞尔。
Like many epithelial-derived cancers, gastric cancer (GC) results from a multistep tumorigenic process. However, the detailed mechanisms involved in GC formation are poorly characterized. Using an ordered differential display method, we have identified rhotekin (RTKN), the gene coding for the Rho effector, RTKN, as one of the genes differentially expressed in human GC. Northern analysis using human multiple tissue blots showed that RTKN is predominantly expressed in the kidney and spinal cord, and, to a lesser degree, in the thyroid, tongue, liver, brain, prostate, trachea, and stomach. RT-PCR analysis confirmed that RTKN was overexpressed in most (5/7; 71%) GC examined. By analyzing the Stanford Microarray Database for the expression profiles of gastric tissues, we also found a progressional increase in RTKN expression in nonneoplastic mucosa, GC, and then lymph node metastases (p < 0.005 by Jonckheere-Terpstra test), suggesting that RTKN expression correlates with GC progression. The role of RTKN in the pathogenic development of GC was investigated by transfection and expression of RTKN in AGS gastric cells, which express endogenous RTKN at a low basal level. Flow-cytometric analysis showed that RTKN-transfected AGS cells were significantly more resistant than vector-transfected cells to apoptosis upon treatment with sodium butyrate. To explore the mechanisms underlying RTKN-mediated cell survival, a reporter assay was performed. Since the NF-kappa B activation is known to promote cell survival and Rho GTPase may lead to NF-kappa B activation, we transfected AGS cells with the RTKN expression vector along with a pNF-kappa B-Luc reporter plasmid. Our results showed that overexpression of RTKN induced robust activation of NF-kappa B, and RTKN-mediated NF-kappa B activation was suppressed significantly by C3 transferase, an inhibitor of the small GTPase Rho. We conclude that Rho/RTKN-mediated NF-kappa B activation leading to cell survival may play a key role in gastric tumorigenesis. This study provides original documentation for the overrepresentation of the Rho GTPase effector rhotekin in human cancer and its links to cancer formation. Copyright (C) 2004 National Science Council, ROC and S. Karger AG, Basel.