MicroRNA-770 affects proliferation and cell cycle transition by directly targeting CDK8 in glioma
MicroRNA-770 affects proliferation and cell cycle transition by directly targeting CDK8 in glioma
复制标题
MicroRNA-770通过直接靶向胶质瘤中的CDK8影响增殖和细胞周期转变
DOI：
10.1186/s12935-018-0694-9
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发表时间：
2018-12-03
影响因子：
5.8
通讯作者：
Zhao, Ling-yu
中科院分区：
文献类型：
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作者：
Zhang, Jun-feng;Zhang, Jian-shui;Zhao, Ling-yu
背景MicroRNA在肿瘤的发生和发展中起着重要作用。据报道，miR-770在几种癌症中下调，并影响癌细胞增殖、凋亡、转移和耐药性。方法采用实时荧光定量PCR（qRT-PCR）方法检测miR-770在人脑胶质瘤组织和细胞系中的表达，探讨miR-770表达与临床病理特征的关系。采用qRT-PCR和Western blotting检测CDK 8在胶质瘤组织中的表达。使用靶标预测程序和双荧光素酶报告基因测定来确认CDK 8是miR-770的靶基因。MTT法和细胞计数法检测miR-770对胶质瘤细胞增殖的影响。流式细胞仪检测细胞周期分布及凋亡情况。CDK 8 siRNA和过表达进一步证实了目的基因的功能。miR-770过表达可抑制胶质瘤细胞增殖和细胞周期G1-S转换，并诱导细胞凋亡。miR-770的抑制促进细胞增殖和G1-S转换，并抑制凋亡。胶质瘤组织中miR-770表达与CDK 8表达呈负相关。通过使用荧光素酶报告基因测定证实CDK 8是miR-770的直接靶标。miR-770的过表达在mRNA和蛋白水平上降低了CDK 8的表达，而miR-770的抑制增加了CDK 8的表达。重要的是，CDK 8沉默重现了在miR-770过表达时观察到的细胞和分子效应，并且CDK 8过表达消除了miR-770过表达对胶质瘤细胞的效应。此外，外源性表达miR-770和沉默CDK 8均能抑制Wnt/β-catenin信号通路。结论我们的研究表明，miR-770通过靶向CDK 8抑制Wnt/β-catenin信号通路，从而抑制胶质瘤细胞增殖和G1-S转化，并诱导细胞凋亡。这些发现表明miR-770在胶质瘤进展中起重要作用，并可作为胶质瘤的潜在治疗靶点。
BackgroundMicroRNAs play crucial roles in tumorigenesis and tumor progression. miR-770 has been reported to be downregulated in several cancers and affects cancer cell proliferation, apoptosis, metastasis and drug resistance. However, the role and underlying molecular mechanism of miR-770 in human glioma remain unknown and need to be further elucidated.MethodsThe expression of miR-770 in glioma tissues and cell lines was measured by quantitative real-time PCR (qRT-PCR) to explore the association of miR-770 expression with clinicopathological characteristics. The expression of CDK8 was detected by qRT-PCR and Western blotting in glioma tissues. A target prediction program and a dual-luciferase reporter assay were used to confirm that CDK8 is a target gene of miR-770. MTT and cell counting assays were used to assess the effect of miR-770 on glioma cell proliferation. The cell cycle distribution and apoptosis were examined by flow cytometry. CDK8 siRNA and overexpression were used to further confirm the function of the target gene.ResultsWe demonstrated that miR-770 expression was downregulated in human glioma tissues and cell lines. The overexpression of miR-770 inhibited glioma cell proliferation and cell cycle G1-S transition and induced apoptosis. The inhibition of miR-770 facilitated cell proliferation and G1-S transition and suppressed apoptosis. miR-770 expression was inversely correlated with CDK8 expression in glioma tissues. CDK8 was confirmed to be a direct target of miR-770 by using a luciferase reporter assay. The overexpression of miR-770 decreased CDK8 expression at both the mRNA and protein levels, and the suppression of miR-770 increased CDK8 expression. Importantly, CDK8 silencing recapitulated the cellular and molecular effects observed upon miR-770 overexpression, and CDK8 overexpression eliminated the effects of miR-770 overexpression on glioma cells. Moreover, both exogenous expression of miR-770 and silencing of CDK8 resulted in suppression of the Wnt/β-catenin signaling pathway.ConclusionsOur study demonstrates that miR-770 inhibits glioma cell proliferation and G1-S transition and induces apoptosis through suppression of the Wnt/β-catenin signaling pathway by targeting CDK8. These findings suggest that miR-770 plays a significant role in glioma progression and serves as a potential therapeutic target for glioma.