MicroRNA miR-199a* regulates the MET proto-oncogene and the downstream extracellular signal-regulated kinase 2 (ERK2)
MicroRNA miR-199a* regulates the MET proto-oncogene and the downstream extracellular signal-regulated kinase 2 (ERK2)
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DOI：
10.1074/jbc.m800186200
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发表时间：
2008-06-27
影响因子：
4.8
通讯作者：
Choi, Young-Chul
中科院分区：
文献类型：
--
作者：
Kim, Seonhoe;Lee, Ui Jin;Choi, Young-Chul
microRNAs（miRNAs）是一类在发育、凋亡、增殖和分化等多种生物学过程中发挥重要作用的非编码小分子RNA。在这里，我们表明，表达的miR-199 a和miR-199 a *（miR-199 a/a*），这是从相同的前体加工，仅限于成纤维细胞中培养的细胞系。成纤维细胞特异性表达模式与甲基化模式相关性良好：在所有检查的细胞系中，1号和19号染色体上的基因位点完全甲基化，但在成纤维细胞中未甲基化。将miR-199 a和/或-199a* 模拟物转染到几种癌细胞系中引起显著的细胞凋亡，其中miR-199 a * 更促细胞凋亡。miR-199 a诱导A549细胞凋亡的机制是caspase依赖性的，而miR-199 a * 诱导A549细胞凋亡的机制是caspase非依赖性的。通过使用微阵列和免疫印迹分析，我们确定MET原癌基因为miR-199 a * 的靶基因。荧光素酶报告基因与MET基因的3 '-非翻译区融合的研究表明，通过miR-199 a * 的结合位点，miR-199 a * 介导的荧光素酶活性下调。有趣的是，细胞外信号调节激酶2（ERK 2）也被miR-199 a * 下调。通过miR 199 a * 协调下调MET及其下游效应器ERK 2可能不仅有效抑制细胞增殖，而且有效抑制肿瘤细胞的运动性和侵袭能力。
MicroRNAs (miRNAs) constitute a class of small noncoding RNAs that play important roles in a variety of biological processes including development, apoptosis, proliferation, and differentiation. Here we show that the expression of miR-199a and miR-199a* (miR-199a/a*), which are processed from the same precursor, is confined to fibroblast cells among cultured cell lines. The fibroblast-specific expression pattern correlated well with methylation patterns: gene loci on chromosome 1 and 19 were fully methylated in all examined cell lines but unmethylated in fibroblasts. Transfection of miR-199a and/or -199a* mimetics into several cancer cell lines caused prominent apoptosis with miR-199a* being more pro-apoptotic. The mechanism underlying apoptosis induced by miR-199a was caspase-dependent, whereas a caspase-independent pathway was involved in apoptosis induced by miR-199a* in A549 cells. By employing microarray and immunoblotting analyses, we identified the MET proto-oncogene as a target of miR-199a*. Studies with a luciferase reporter fused to the 3'-untranslated region of the MET gene demonstrated miR-199a*-mediated down-regulation of luciferase activity through a binding site of miR-199a*. Interestingly, extracellular signal-regulated kinase 2 (ERK2) was also down-regulated by miR-199a*. Coordinated down-regulation of both MET and its downstream effector ERK2 by miR199a* may be effective in inhibiting not only cell proliferation but also motility and invasive capabilities of tumor cells.