微小RNA-645在人胃食管交界腺癌中上调，通过靶向肿瘤抑制因子IFIT2抑制细胞凋亡。
MicroRNA-645, up-regulated in human adencarcinoma of gastric esophageal junction, inhibits apoptosis by targeting tumor suppressor IFIT2.
作者信息
Feng Xiaoshan, Wang Ying, Ma Zhikun, Yang Ruina, Liang Shuo, Zhang Mengxi, Song Shiyuan, Li Shuoguo, Liu Gang, Fan Daiming, Gao Shegan
机构信息
Oncology Department of the First Affiliated Hospital of Henan, University of Science and Technology, No, 24 Jinghua Road, Luoyang, Henan, China.
出版信息
BMC Cancer. 2014 Aug 29;14:633. doi: 10.1186/1471-2407-14-633.
BACKGROUND
An increasing body of evidence indicates that miRNAs have a critical role in carcinogenesis and cancer progression; however, the role of miRNAs in the tumorigenesis of adencarcinoma of gastric esophageal junction (AGEJ) remains largely unclear.
METHODS
The SGC7901 and BGC-823 gastric cancer cell lines were used. The expressions of miR-645 and IFIT2 (Interferon-induced protein with tetratricopeptide repeats 2) were examined by qRT-PCR, The expressions of IFIT2 was examined by western blotting and immunohistochemistry assay. The cell apoptosis was determined by FACS. MiR-645 inhibitor, mimics and plasmid-IFIT2 transfections were performed to study the loss- and gain-function. Caspase-3/7 activity was examined by caspase-3/7 assay.
RESULTS
In the present study, we have reported an increased expression of miR-645 in AGEJ clinical specimens compared with paired non-cancerous tissues. We also observed a significant miR-645 up-regulation in two gastric cancer (GC) cell lines, SGC7901 and BGC-823, which were used as cell models because there was no available AGEJ cell lines established to date. We found that inhibition of miR-645 could sensitize dramatically SGC7901 and BGC-823 cells to both serum starvation- and chemotherapeutic drug-induced apoptosis by up-regulating IFIT2, a mediator of apoptosis via a mitochondrial pathway, with a potential binding site for miR-645 in its mRNA's 3'UTR. Further investigation exhibited that IFIT2 expression decreases in SGC7901 and BGC-823 cells and AGEJ tissues. IFIT2 ectopic expression leads to promotion of cell apoptosis, indicating that IFIT2 may function as a suppressor in the development of AGEJ. Furthermore, inhibition of miR-645 induces up-regulation of IFIT2 and increased caspase-3/7 activity compared with control groups.
CONCLUSIONS
Our data suggest that miR-645 functions as an oncogene in human AGEJ by, at least partially through, targeting IFIT2.
背景
越来越多的证据表明，微小RNA（miRNAs）在肿瘤发生和癌症进展中起关键作用；然而，miRNAs在胃食管交界腺癌（AGEJ）肿瘤发生中的作用仍 largely不清楚。
方法
使用SGC7901和BGC - 823胃癌细胞系。通过qRT - PCR检测miR - 645和干扰素诱导的四肽重复蛋白2（IFIT2）的表达，通过蛋白质免疫印迹和免疫组织化学检测IFIT2的表达。通过流式细胞术测定细胞凋亡。进行miR - 645抑制剂、模拟物和质粒 - IFIT2转染以研究功能丧失和功能获得。通过caspase - 3/7检测法检测caspase - 3/7活性。
结果
在本研究中，我们报道与配对的非癌组织相比，miR - 645在AGEJ临床标本中的表达增加。我们还观察到在两种胃癌（GC）细胞系SGC7901和BGC - 823中miR - 645显著上调，由于迄今为止尚未建立可用的AGEJ细胞系，因此将这两种细胞系用作细胞模型。我们发现抑制miR - 645可通过上调IFIT2使SGC7901和BGC - 823细胞对血清饥饿和化疗药物诱导的凋亡显著敏感，IFIT2是通过线粒体途径的凋亡介质，其mRNA的3'UTR中有一个潜在的miR - 645结合位点。进一步研究表明，IFIT2在SGC7901和BGC - 823细胞以及AGEJ组织中的表达降低。IFIT2异位表达导致细胞凋亡增加，表明IFIT2可能在AGEJ的发生发展中起抑制作用。此外，与对照组相比，抑制miR - 645可诱导IFIT2上调并增加caspase - 3/7活性。
结论
我们的数据表明，miR - 645至少部分通过靶向IFIT2在人类AGEJ中发挥癌基因作用。
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