The miRNA let-7a1 inhibits the expression of insulin-like growth factor 1 receptor (IGF1R) in prostate cancer PC-3 cells
The miRNA let-7a1 inhibits the expression of insulin-like growth factor 1 receptor (IGF1R) in prostate cancer PC-3 cells
复制标题
miRNA let-7a1 抑制前列腺癌 PC-3 细胞中胰岛素样生长因子 1 受体 (IGF1R) 的表达。
DOI：
10.1038/aja.2013.84
复制
发表时间：
2013-11-01
影响因子：
2.9
通讯作者：
Jiang, An-Li
中科院分区：
文献类型：
--
作者：
Wang, Li-Na;Chen, Wei-Wen;Jiang, An-Li
微RNA(MiRNA)let-7a表达降低和胰岛素样生长因子-1受体(IGF1R)信号激活均参与前列腺癌的发生和发展。在本研究中，我们证明了let-7A1的生长抑制作用与靶向IGF1R基因在PC-3细胞中的表达直接相关。TargetScan预测了IGF1R基因3‘非翻译区中let-7a的三个潜在靶点(T1、T2和T3)。采用实时定量聚合酶链式反应、Western印迹和荧光素酶报告基因检测等方法检测LET-7A1过表达或LET-7A1抑制剂对PC-3细胞IGF1R基因表达的影响。结果表明，let-7A1通过直接靶向IGF1R基因3‘端非编码区的T1和T2位点，抑制IGF1R的表达。采用逆转录聚合酶链式反应、荧光素酶报告基因检测、3-(4，5-二甲基噻唑-2-基)-2，5-二苯基-2H-四唑溴化法、流式细胞仪和Hoechst 33342染色等方法，检测let-7A1抑制IGF1R表达是否也影响IGF1R介导的信号转导过程，包括ELK1活性和c-fos基因表达、细胞增殖、细胞凋亡和细胞周期。我们发现，LET-7A1介导的IGF1R下调伴随着ELK1活性和c-fos表达的降低，抑制细胞增殖，促进细胞凋亡和细胞周期停滞，而通过抑制LET-7A1而丧失功能可以上调IGF1R，同时ELK1活性和c-fos表达增加，从而促进细胞增殖。总之，这些发现表明let-7a可能是前列腺癌的新候选治疗药物。
Reduced microRNA (miRNA) let-7a expression and the activation of insulin-like growth factor-1 receptor (IGF1R) signalling are both involved in prostate cancer and progression. In the present study, we demonstrated that the growth inhibitory effect of let-7a1 is directly related to targeting IGF1R gene expression in PC-3 cells. TargetScan predicted three potential target sites (T1, T2 and T3) of let-7a in the 3′ untranslational region (3′ UTR) of IGF1R mRNA. Real-time PCR, Western blot and luciferase reporter assays were used to detect the effects of let-7a1 overexpression or let-7a1 inhibitor on the IGF1R gene expression in PC-3 cells. The results indicated that let-7a1 could inhibit IGF1R expression by directly targeting the T1 and T2 sites in the 3′ UTR of the IGF1R mRNA. We then used RT-PCR, luciferase reporter assays, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay, flow cytometry and Hoechst 33342 staining to examine whether let-7a1-mediated inhibition of IGF1R expression also affects the IGF1R-mediated signalling events, including Elk1 activity and c-fos gene expression, proliferation, apoptosis and cell cycle. We demonstrated that let-7a1-mediated IGF1R downregulation was accompanied by attenuation of Elk1 activity and c-fos expression, inhibition of cell proliferation, enhanced apoptosis and cell cycle arrest, and that loss function of let-7a1 via inhibition can upregulate IGF1R accompanied by an increase of Elk1 activity and c-fos expression, thereby enhancing cell proliferation. Altogether, these findings suggest that let-7a may be novel therapeutic candidate for prostate cancer.