Wang Hao, Nie Lei, Wu Lei, Liu Qiufang, Guo Xueyan
Department of Radiotherapy, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, PR China; Center of Radiotherapy, Shaanxi Provincial Tumor Hospital, Xi'an, Shaanxi 710061, PR China.
Department of Oncology, Shaanxi Provincial Tumor Hospital, Xi'an, Shaanxi 710061, PR China.
Biochem Biophys Res Commun. 2017 Mar 25;485(1):181-188. doi: 10.1016/j.bbrc.2017.02.049. Epub 2017 Feb 10.
Metastasis is one of the most decisive factors influencing CRC patient prognosis and current studies suggest that a molecular mechanism known as EMT broadly regulates cancer metastasis. NR2F2 is a key molecule in the development of CRC, but the roles and underlying mechanisms of NR2F2 in TGF-β induced EMT in CRC remain largely unknown. In the current study, we were interested to examine the role of NR2F2 in the TGF-β-induced EMT in CRC. Here, we found NR2F2 was upregulated in CRC cells and promotes TGF-β-induced EMT in CRC. Using comparative miRNA profiling TGF-β pre-treated CRC cells in which NR2F2 had been knocked down with that of control cells, we identified miR-21 as a commonly downregulated miRNA in HT29 cells treated with TGF-β and NR2F2 siRNA, and its downregulation inhibiting migration and invasion of CRC cells. Moreover, we found NR2F2 could transcriptional activated miR-21 expression by binding to miR-21 promoter in HT29 by ChIP and luciferase assay. In the last, our data demonstrated that Smad7 was the direct target of miR-21 in CRC cells. Thus, NR2F2 could promote TGF-β-induced EMT and inhibit Smad7 expression via transactivation of miR-21, and NR2F2 may be a new common therapeutic target for CRC.
转移是影响结直肠癌患者预后的最关键因素之一，目前的研究表明，一种称为上皮-间质转化（EMT）的分子机制广泛调节癌症转移。NR2F2是结直肠癌发生发展中的关键分子，但NR2F2在转化生长因子-β（TGF-β）诱导的结直肠癌EMT中的作用及潜在机制仍 largely未知。在本研究中，我们旨在探讨NR2F2在TGF-β诱导的结直肠癌EMT中的作用。在此，我们发现NR2F2在结直肠癌细胞中上调，并促进TGF-β诱导的结直肠癌EMT。通过对NR2F2敲低的TGF-β预处理结直肠癌细胞与对照细胞进行比较性微小RNA（miRNA）谱分析，我们确定miR-21是TGF-β和NR2F2小干扰RNA（siRNA）处理的HT29细胞中共同下调的miRNA，其下调抑制了结直肠癌细胞的迁移和侵袭。此外，我们通过染色质免疫沉淀（ChIP）和荧光素酶测定发现NR2F2可通过与HT29细胞中miR-21启动子结合转录激活miR-21表达。最后，我们的数据表明Smad7是结直肠癌细胞中miR-21的直接靶标。因此，NR2F2可通过miR-21的反式激活促进TGF-β诱导的EMT并抑制Smad7表达，NR2F2可能是结直肠癌一种新的共同治疗靶点。
