Shb gene knockdown increases the susceptibility of SVR endothelial tumor cells to apoptotic stimuli in vitro and in vivo
Shb gene knockdown increases the susceptibility of SVR endothelial tumor cells to apoptotic stimuli in vitro and in vivo
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DOI：
10.1038/sj.jid.5701057
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发表时间：
2008-03-01
影响因子：
6.5
通讯作者：
Arbiser, Jack L.
中科院分区：
文献类型：
--
作者：
Funa, Nina S.;Reddy, Kalpana;Arbiser, Jack L.
SHB接头蛋白是一个Src同源的2-结构域，包含在几种酪氨酸激酶受体下游的信号中间产物，包括血管内皮生长因子受体-2。SHB是多功能的，细胞凋亡是SHB调节的一种反应。抑制血管生成可用于癌症治疗，其中一种方法是通过诱导内皮细胞凋亡来实现这一点。血管肉瘤细胞系SVR是内皮源性的，可以作为体内研究血管生成抑制的工具，因此我们采用SHB基因敲除策略，使用可诱导的慢病毒系统来降低SVR细胞中SHB的水平并研究其反应。SHB基因敲除增加了SVR细胞对凋亡剂顺铂和星形孢子素的敏感性。同时，SHB基因敲除导致粘着斑激酶(FAK)活性降低，被监测为调节残基酪氨酸576/577的磷酸化。未发现对Akt或细胞外信号调节激酶活性的影响。改变的FAK活性与细长的细胞表型相一致，这在星状孢子素存在时特别明显。为了将SHB基因敲除对体内致瘤性的影响联系起来，将细胞暴露在血管生成抑制剂和厚朴酚中，SHB含量降低的细胞再次表现出更多的凋亡。和厚朴酚治疗后，SHB基因敲除细胞体内的肿瘤生长明显减少。结论：SHB通过FAK调节肿瘤内皮细胞的凋亡和细胞形态，是抑制血管生成的潜在靶点。
The Shb adapter protein is an Src homology 2-domain containing signaling intermediate operating downstream of several tyrosine kinase receptors, including vascular endothelial growth factor receptor-2. Shb is multifunctional and apoptosis is one response that Shb regulates. Inhibition of angiogenesis can be used in cancer therapy, and one way to achieve this is by inducing endothelial cell apoptosis. The angiosarcoma cell line SVR is of endothelial origin and can be used as a tool for studying in vivo inhibition of angiogenesis, and we thus employed an Shb-knockdown strategy using an inducible lentiviral system to reduce Shb levels in SVR cells and to study their responses. Shb knockdown increases the susceptibility of SVR cells to the apoptotic agents, cisplatin and staurosporine. Simultaneously, Shb knockdown causes reduced focal adhesion kinase (FAK) activation, monitored as phosphorylation of the regulatory residues tyrosines 576/577. No detectable effects on Akt or extracellular signal-regulated kinase activity were noted. The altered FAK activity coincided with an elongated cell phenotype that was particularly noticeable in the presence of staurosporine. In order to relate the effects of Shb knockdown to in vivo tumorigenicity, cells were exposed to the angiogenesis inhibitor honokiol, and again the cells with reduced Shb content exhibited increased apoptosis. Tumor growth in vivo was strongly reduced in the Shb-knockdown cells upon honokiol treatment. It is concluded that Shb regulates apoptosis and cell shape in tumor endothelial cells via FAK, and that Shb is a potential target for inhibition of angiogenesis.