The miR-200 family inhibits epithelial-mesenchymal transition and cancer cell migration by direct targeting of E-cadherin transcriptional repressors ZEB1 and ZEB2
The miR-200 family inhibits epithelial-mesenchymal transition and cancer cell migration by direct targeting of E-cadherin transcriptional repressors ZEB1 and ZEB2
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DOI：
10.1074/jbc.c800074200
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发表时间：
2008-05-30
影响因子：
4.8
通讯作者：
Kang, Yibin
中科院分区：
文献类型：
--
作者：
Korpal, Manav;Lee, Esther S.;Kang, Yibin
MicroRNA是一种非编码RNA小分子，可通过与多个mRNA相互作用并诱导mRNA的翻译抑制或降解来调节基因表达。最近，几种miRNA被鉴定为转移的启动子或抑制子。然而，目前尚不清楚这些miRNA在多步转移级联的哪个步骤中发挥确定的功能作用。为了研究miRNA在上皮-间质转化（EMT）中的功能重要性，EMT是一个被认为通过增强肿瘤细胞的运动性来启动转移的过程，我们使用了一种成熟的体外EMT测定：转化生长因子β诱导的NMuMG小鼠乳腺上皮细胞中的EMT。我们发现，miR-200家族的成员，在基因组中组织为两个簇，在EMT期间被抑制。在NMuMG细胞中，每种miRNA单独或成簇过表达通过直接靶向编码E-钙粘蛋白转录抑制因子的ZEB 1和ZEB 2增强E-钙粘蛋白表达来阻碍EMT。在表达低水平内源性E-钙粘蛋白并显示间充质表型的4 TO 7小鼠癌细胞系中，miR-200家族miRNA的异位表达显著增加了E-钙粘蛋白的表达，并将细胞形态改变为上皮表型。此外，在迁移测定中，每个miR-200 miRNA簇的异位表达显著降低了4 TO 7细胞的体外运动性。这些结果表明，miR-200家族成员的表达缺失可能在EMT期间ZEB 1和ZEB 2对E-钙粘蛋白的抑制中发挥关键作用，从而增强癌症进展期间的迁移和侵袭。
MicroRNAs are small non-coding RNA molecules that can regulate gene expression by interacting with multiple mRNAs and inducing either translation suppression or degradation of mRNA. Recently, several miRNAs were identified as either promoters or suppressors of metastasis. However, it is unclear in which step(s) of the multistep metastatic cascade these miRNAs play a defined functional role. To study the functional importance of miRNAs in epithelial-mesenchymal transition (EMT), a process thought to initiate metastasis by enhancing the motility of tumor cells, we used a well established in vitro EMT assay: transforming growth factor-beta-induced EMT in NMuMG murine mammary epithelial cells. We found that members of the miR-200 family, organized as two clusters in the genome, were repressed during EMT. Overexpression of each miRNA individually or as clusters in NMuMG cells hindered EMT by enhancing E-cadherin expression through direct targeting of ZEB1 and ZEB2, which encode transcriptional repressors of E-cadherin. In the 4TO7 mouse carcinoma cell line, which expresses low levels of endogenous E-cadherin and displays a mesenchymal phenotype, ectopic expression of the miR-200 family miRNAs significantly increased E-cadherin expression and altered cell morphology to an epithelial phenotype. Furthermore, ectopic expression of each miR-200 miRNA cluster significantly reduced the in vitro motility of 4TO7 cells in migration assays. These results suggested that loss of expression of the miR-200 family members may play a critical role in the repression of E-cadherin by ZEB1 and ZEB2 during EMT, thereby enhancing migration and invasion during cancer progression.