MicroRNA-138 suppresses epithelial-mesenchymal transition in squamous cell carcinoma cell lines.
MicroRNA-138 suppresses epithelial-mesenchymal transition in squamous cell carcinoma cell lines.
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MicroRNA-138 抑制鳞状细胞癌细胞系的上皮间质转化。
DOI：
10.1042/bj20111006
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发表时间：
2011-11-15
期刊：
影响因子：
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通讯作者：
Zhou X
中科院分区：
文献类型：
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作者：
Liu X;Wang C;Chen Z;Jin Y;Wang Y;Kolokythas A;Dai Y;Zhou X
miR-138（microRNA-138）的下调在各种癌症中经常观察到，包括HNSCC（头颈部鳞状细胞癌）。我们以前的研究表明，下调miR-138与间充质样细胞形态和增强的细胞迁移和侵袭有关。在本研究中，我们证明了这些miR-138诱导的变化伴随着E-cad（E-cadherin）表达的显著降低和Vim（vimentin）表达的增强，这是EMT（上皮-间充质转化）的特征。在结合实验和生物信息学分析的基础上，我们确定了许多与EMT相关的miR-138靶基因，包括Vim，ZEB 2（锌指E-box-binding homeobox 2）和EZH 2（zeste同源增强子2）。使用荧光素酶报告基因测定证实miR-138直接靶向位于Vim、ZEB 2和EZH 2基因mRNA中的特定序列。我们的功能分析（敲入和敲低）证明miR-138通过三种不同的途径调节EMT：（i）直接靶向Vim mRNA并在转录后水平控制Vim的表达，（ii）靶向转录阻遏物（ZEB 2），其进而调节E-cad基因的转录活性，和（iii）靶向表观遗传调节因子EZH 2，EZH 2又调节其对下游基因（包括E-cad）的基因沉默作用。这些结果，连同我们先前观察到的miR-138通过同时靶向RhoC（Rho相关的GTP结合蛋白C）和ROCK 2（Rho相关的、含有卷曲螺旋的蛋白激酶2）对细胞迁移和侵袭的影响，表明miR-138是一种多功能分子调节剂，在EMT和HNSCC进展中起主要作用。
Down-regulation of miR-138 (microRNA-138) has been frequently observed in various cancers, including HNSCC (head and neck squamous cell carcinoma). Our previous studies suggest that down-regulation of miR-138 is associated with mesenchymal-like cell morphology and enhanced cell migration and invasion. In the present study, we demonstrated that these miR-138-induced changes were accompanied by marked reduction in E-cad (E-cadherin) expression and enhanced Vim (vimentin) expression, characteristics of EMT (epithelial-mesenchymal transition). On the basis of a combined experimental and bioinformatics analysis, we identified a number of miR-138 target genes that are associated with EMT, including VIM, ZEB2 (zinc finger E-box-binding homeobox 2) and EZH2 (enhancer of zeste homologue 2). Direct targeting of miR-138 to specific sequences located in the mRNAs of the VIM, ZEB2 and EZH2 genes was confirmed using luciferase reporter gene assays. Our functional analyses (knock-in and knock-down) demonstrated that miR-138 regulates the EMT via three distinct pathways: (i) direct targeting of VIM mRNA and controlling the expression of VIM at a post-transcriptional level, (ii) targeting the transcriptional repressors (ZEB2) which in turn regulating the transcription activity of the E-cad gene, and (iii) targeting the epigenetic regulator EZH2 which in turn modulates its gene silencing effects on the downstream genes including E-cad. These results, together with our previously observed miR-138 effects on cell migration and invasion through targeting RhoC (Rho-related GTP-binding protein C) and ROCK2 (Rho-associated, coiled-coil-containing protein kinase 2) concurrently, suggest that miR-138 is a multi-functional molecular regulator and plays major roles in EMT and in HNSCC progression.