Ma Zhong-Liang, Hou Pin-Pin, Li Yan-Li, Wang De-Tao, Yuan Tian-Wei, Wei Jia-Li, Zhao Bo-Tao, Lou Jia-Tao, Zhao Xin-Tai, Jin Yan, Jin You-Xin
School of Life Sciences, Shanghai University, Shanghai, 200444, China.
Tumour Biol. 2015 Apr;36(4):2481-90. doi: 10.1007/s13277-014-2861-5. Epub 2014 Dec 13.
MicroRNAs (MiRNAs) are small non-coding RNA molecules which act as important regulators of post-transcriptional gene expression by binding 3'-untranslated region (3'-UTR) of target messenger RNA (mRNA). In this study, we analyzed miRNA-34a (miR-34a) as a tumor suppressor in non-small cell lung cancer (NSCLC) H1299 cell line. The expression level of miR-34a in four different NSCLC cell lines, H1299, A549, SPCA-1, and HCC827, was significantly lower than that in the non-tumorigenic bronchial epithelium cell line BEAS-2B. In human NSCLC tissues, miR-34a expression level was also significantly decreased in pT2-4 compared with the pT1 group. Moreover, miR-34a mimic could inhibit the proliferation and triggered apoptosis in H1299 cells. Luciferase assays revealed that miR-34a inhibited TGFβR2 expression by targeting one binding site in the 3'-UTR of TGFβR2 mRNA. Quantitative real-time PCR (qRT-PCR) and Western blot assays verified that miR-34a reduced TGFβR2 expression at both mRNA and protein levels. Furthermore, downregulation of TGFβR2 by siRNA showed the same effects on the proliferation and apoptosis as miR-34a mimic in H1299 cells. Our results demonstrated that miR-34a could inhibit the proliferation and promote the apoptosis of H1299 cells partially through the downregulation of its target gene TGFβR2.
微小RNA（miRNA）是一类小的非编码RNA分子，通过与靶信使RNA（mRNA）的3'非翻译区（3'-UTR）结合，作为转录后基因表达的重要调节因子。在本研究中，我们分析了miRNA-34a（miR-34a）在非小细胞肺癌（NSCLC）H1299细胞系中作为肿瘤抑制因子的作用。miR-34a在四种不同的NSCLC细胞系H1299、A549、SPCA-1和HCC827中的表达水平显著低于非致瘤性支气管上皮细胞系BEAS-2B。在人NSCLC组织中，与pT1组相比，pT2-4期miR-34a的表达水平也显著降低。此外，miR-34a模拟物可抑制H1299细胞的增殖并引发凋亡。荧光素酶报告基因检测显示，miR-34a通过靶向TGFβR2 mRNA的3'-UTR中的一个结合位点来抑制TGFβR2的表达。定量实时PCR（qRT-PCR）和蛋白质免疫印迹分析证实，miR-34a在mRNA和蛋白质水平上均降低了TGFβR2的表达。此外，siRNA介导的TGFβR2下调对H1299细胞增殖和凋亡的影响与miR-34a模拟物相同。我们的结果表明，miR-34a可通过下调其靶基因TGFβR2来部分抑制H1299细胞的增殖并促进其凋亡。
