Department of Molecular Cytogenetics, Tokyo Medical and Dental University, Tokyo, Japan.
PLoS One. 2013 May 14;8(5):e62757. doi: 10.1371/journal.pone.0062757. Print 2013.
Recently, the epithelial-to-mesenchymal transition (EMT) has been demonstrated to contribute to normal and disease processes including cancer progression. To explore EMT-suppressive microRNAs (miRNAs), we established a cell-based reporter system using a stable clone derived from a pancreatic cancer cell line, Panc1, transfected with a reporter construct containing a promoter sequence of CDH1/E-cadherin in the 5' upstream region of the ZsGreen1 reporter gene. Then, we performed function-based screening with 470 synthetic double-stranded RNAs (dsRNAs) mimicking human mature miRNAs using the system and identified miR-655 as a novel EMT-suppressive miRNA. Overexpression of miR-655 not only induced the upregulation of E-cadherin and downregulation of typical EMT-inducers but also suppressed migration and invasion of mesenchymal-like cancer cells accompanied by a morphological shift toward the epithelial phenotype. In addition, we found a significant correlation between miR-655 expression and a better prognosis in esophageal squamous cell carcinoma (ESCC). Moreover, ZEB1 and TGFBR2, which are essential components of the TGF-b signaling pathway, were identified as direct targets of miR-655, suggesting that the activation of the TGF-b-ZEB1-E-cadherin axis by aberrant downregulation of miR-655 may accelerate cancer progression.
最近，上皮-间充质转化 (EMT) 被证明有助于包括癌症进展在内的正常和疾病过程。为了探索 EMT 抑制性 microRNA（miRNA），我们使用源自胰腺癌细胞系 Panc1 的稳定克隆建立了基于细胞的报告系统，该克隆通过报告构建体转染，该报告构建体包含 ZsGreen1 报告基因上游区域的 CDH1/E-钙粘蛋白启动子序列。然后，我们使用该系统对 470 个人类成熟 miRNA 的合成双链 RNA（dsRNA）进行了基于功能的筛选，鉴定出 miR-655 是一种新型的 EMT 抑制性 miRNA。miR-655 的过表达不仅诱导 E-钙粘蛋白的上调和典型 EMT 诱导剂的下调，还抑制了间充质样癌细胞的迁移和侵袭，并伴有向上皮表型的形态转变。此外，我们发现 miR-655 的表达与食管鳞状细胞癌（ESCC）的预后较好有显著相关性。此外，ZEB1 和 TGFBR2 被鉴定为 miR-655 的直接靶标，它们是 TGF-β信号通路的重要组成部分，这表明异常下调 miR-655 激活 TGF-β-ZEB1-E-钙粘蛋白轴可能加速癌症进展。
