Transcriptional repressors of E-cadherin in metastasis

描述(申请人提供)：侵袭性癌以上皮间充质转化(EMT)为特征。EMT的特点，细胞间相互作用的丧失和细胞运动的增加，加强了癌细胞从原发肿瘤部位的外逃，增加了转移的可能性。在许多上皮细胞系中，持续的肿瘤生长因子-β1(TGF-β1)信号是启动和维持EMT所必需的。多种转化生长因子-β1诱导的E-钙粘蛋白转录抑制因子(TITR)参与了EMT，包括Snail、Slug、ZeB-1和ZeB-2。我们将通过使用TITRs的显性负版本、针对TITRs的小干扰RNA(SiRNA)和单个TITRs在EpH4细胞中的过表达来验证这一假设，即细胞对EMT的承诺可能由涉及TITRs的正和负反馈环决定。为了确定这些TITRs在EMT介导的转移中的作用，我们将在体内确定TITRs是否会导致EpH4细胞转移潜能的增加。最后，利用新建立的基于siRNA的全基因组筛选，我们将识别控制TITRs表达的共有的转化生长因子-β1下游信号因子，为预防转移提供治疗靶点。

DESCRIPTION (provided by applicant): Aggressive carcinomas are characterized by epithelial to mesenchymal transition (EMT). The hallmarks of EMT, loss of cell-cell interactions and an increase in cell motility, potentiate the exodus of cancer cells from the primary tumor site, increasing the likelihood of metastasis. In a number of epithelial cell lines continuous tumor growth factor beta 1 (TGF-beta1) signaling is necessary for initiating and maintaining EMT. Multiple TGF-beta1 induced transcriptional repressors (TITR) of E-cadherin have been implicated in EMT, including Snail, Slug, ZEB-1 and ZEB-2. We will test the hypothesis that a cell's commitment to EMT may be determined by positive and negative feedback loops involving the TITRs by using dominant negative versions of the TITRs, small interfering RNA (siRNA) directed towards the TITRs and overexpression of the individual TITRs in EpH4 cells. To firmly establish the role of these TITRs in EMT mediated metastasis, we will determine in vivo if the TITRs cause increased metastatic potential of EpH4 cells. Finally using a newly established genome wide screen based on siRNA we will identify shared downstream signaling factors of TGF-beta1 that control the expression of the TITRs, providing therapeutic targets for preventing metastasis.