MicroRNA-375 Is Downregulated in Gastric Carcinomas and Regulates Cell Survival by Targeting PDK1 and 14-3-3ζ
MicroRNA-375 Is Downregulated in Gastric Carcinomas and Regulates Cell Survival by Targeting PDK1 and 14-3-3ζ
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DOI：
10.1158/0008-5472.can-09-2777
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发表时间：
2010-03-15
期刊：
影响因子：
11.2
通讯作者：
Moriyama, Masatsugu
中科院分区：
文献类型：
--
作者：
Tsukamoto, Yoshiyuki;Nakada, Chisato;Moriyama, Masatsugu
我们使用涵盖总共 470 种人类 miRNA 的 miRNA 微阵列平台研究了胃癌中 microRNA (miRNA) 的表达谱。我们鉴定出胃癌中 39 个差异表达的 miRNA，其中 6 个显着下调，另外 33 个上调。我们发现 miRNA-375 (miR-375) 的下调幅度最大，并且其在胃癌细胞中的异位表达通过 caspase 介导的凋亡途径显着降低细胞活力。有趣的是，我们发现 miR-375 的表达抑制 PDK1（miR-375 的直接靶标）的表达，进而抑制 Akt 磷酸化。基因表达微阵列的进一步分析表明，14-3-3 zeta（一种有效的抗凋亡基因）在转染 miR-375 的细胞中的 mRNA 和蛋白质水平均显着下调。 14-3-3 zeta mRNA 3'非翻译区（UTR）处含有 miR-375 结合序列的荧光素酶报告基因的活性受到 miR-375 异位表达的抑制，表明 miR-375 靶向 14-3-3 zeta 的 3' UTR。此外，胃癌细胞中 PDK1 或 14-3-3 zeta 的敲低会诱导 caspase 激活，这在 miR-375 转染的细胞中也观察到，表明 miR-375 可能至少部分通过 PDK1 和 14-3-3 zeta 的下调发挥其促凋亡功能。综上所述，我们提出 miR-375 是胃癌中的候选抑癌 miRNA。癌症研究； 70(6)； 2339-49。 (C) 2010 AACR。
We investigated expression profiles of microRNA (miRNA) in gastric carcinomas by use of a miRNA microarray platform covering a total of 470 human miRNAs. We identified 39 differentially expressed miRNAs in gastric carcinoma, of which six were significantly downregulated and the other 33 were upregulated. We found that miRNA-375 (miR-375) was the most downregulated and that its ectopic expression in gastric carcinoma cells markedly reduced cell viability via the caspase-mediated apoptosis pathway. Interestingly, we found that expression of miR-375 inhibited expression of PDK1, which is a direct target of miR-375, followed by suppression of Akt phosphorylation. Further analysis by gene expression microarray revealed that 14-3-3 zeta, a potent antiapoptotic gene, was significantly downregulated at both the mRNA and protein levels in cells transfected with miR-375. The activity of a luciferase reporter containing the miR-375 binding sequence at the 3' untranslated region (UTR) of 14-3-3 zeta mRNA was repressed by the ectopic expression of miR-375, suggesting that miR-375 targets the 3' UTR of 14-3-3 zeta. In addition, knockdown of either PDK1 or 14-3-3 zeta in gastric carcinoma cells induced caspase activation, which was also observed in miR-375-transfected cells, suggesting that miR-375 may exert its proapoptotic function, at least in part, through the downregulation of PDK1 and 14-3-3 zeta. Taken together, we propose that miR-375 is a candidate tumor suppressor miRNA in gastric carcinoma. Cancer Res; 70(6); 2339-49. (C) 2010 AACR.