Transcriptional repressors of E-cadherin in metastasis

描述（由申请人提供）：侵袭性癌的特征是上皮向间质转化（EMT）。EMT的标志，细胞-细胞相互作用的丧失和细胞运动性的增加，增强了癌细胞从原发肿瘤部位的外流，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β 1（TGF-beta1）信号传导对于启动和维持EMT是必要的。E-cadherin的多种TGF-β 1诱导的转录抑制因子（TITR）与EMT有关，包括Snail、Slug、ZEB-1和ZEB-2。我们将测试这样的假设，即细胞对EMT的承诺可以通过涉及TITRs的正反馈和负反馈回路来确定，这是通过使用TITRs的显性负反馈版本、针对TITRs的小干扰RNA（siRNA）和EpH 4细胞中单个TITRs的过表达来确定的。为了牢固地确立这些TITR在EMT介导的转移中的作用，我们将在体内确定TITR是否引起EpH 4细胞的转移潜力增加。最后，使用新建立的基于siRNA的全基因组筛选，我们将鉴定控制TITRs表达的TGF-β 1的共享下游信号传导因子，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.