microRNA-18a, a member of the oncogenic miR-17-92 cluster, targets Dicer and suppresses cell proliferation in bladder cancer T24 cells
microRNA-18a, a member of the oncogenic miR-17-92 cluster, targets Dicer and suppresses cell proliferation in bladder cancer T24 cells
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DOI：
10.3892/mmr.2011.591
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发表时间：
2012-01-01
影响因子：
3.4
通讯作者：
Zhang, Wei
中科院分区：
文献类型：
--
作者：
Tao, Jun;Wu, Deyao;Zhang, Wei
miR-17-92簇长期以来被认为是致癌microRNA（miRNA）簇，并在多种癌症中扩增。然而，其成员在致癌作用中的个体作用在很大程度上是不确定的。转染miR-18 a模拟物、反义寡核苷酸抑制剂、siRNA和荧光素酶报告质粒后，在膀胱癌细胞中进行MU测定、集落形成测定、半定量RT-PCR、荧光素酶测定和Western印迹分析。在本研究中，我们发现miR-17-92簇的成员miR-18 a抑制膀胱癌T24细胞的细胞增殖。miR-18 a在T24细胞中的异位表达可在mRNA和蛋白水平下调Dicer的表达，而反义寡核苷酸抑制miR-18 a可增强T24细胞中Dicer的表达。miR-18 a在Dicer 3'非翻译区（3' UTR）有两个结合位点。荧光素酶报告基因分析表明，这两个位点可以介导的表达抑制在体外。此外，通过siRNA敲低Dicer表达模拟了T24细胞中miR-18 a诱导的细胞生长抑制。这些结果表明，miR-18 a通过靶向膀胱癌T24细胞中的Dicer而发挥肿瘤抑制剂的作用，并揭示了值得注意的反馈环，该反馈环可被miR-17-92簇用于控制miRNA输出并防止其过表达。
The miR-17-92 cluster has long been recognized as an oncogenic microRNA (miRNA) cluster and is amplified in multiple cancers. However, the individual roles of its members in carcinogenesis are largely undetermined. After transfection of miR-18a mimics, an antisense oligonucleotides inhibitor, siRNAs and a luciferase reporter plasmid, the MU assay, colony formation assay, semi-quantitative RT-PCR, luciferase assay and Western blot analysis were conducted in bladder cancer cells. In the present study, we showed that miR-18a, a member of the miR-17-92 cluster, suppressed cell proliferation in bladder cancer T24 cells. Furthermore, ectopic expression of miR-18a in T24 cells down-regulated Dicer expression at both the mRNA and protein level, while inhibition miR-18a by antisense oligonucleotides could enhance Dicer expression in T24 cells. Two binding sites of miR-18a were found in Dicer 3' untranslated region (3' UTR). Luciferase reporter assay demonstrated that both sites could mediate expression suppression in vitro. In addition, knockdown of Dicer expression by si RNA mimicked cell growth suppression induced by miR-18a in T24 cells. These results show that miR-18a functions as a tumor suppressor by targeting Dicer in bladder cancer T24 cells and revealed a noteworthy feedback loop, which may be utilized by the miR-17-92 cluster to control miRNA output and prevent its overexpression.