miR-185 Inhibits Hepatocellular Carcinoma Growth by Targeting the DNMT1/PTEN/Akt Pathway
miR-185 Inhibits Hepatocellular Carcinoma Growth by Targeting the DNMT1/PTEN/Akt Pathway
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DOI：
10.1016/j.ajpath.2014.05.004
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发表时间：
2014-08-01
影响因子：
6
通讯作者：
Wu, Tong
中科院分区：
文献类型：
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作者：
Qadir, Ximena V.;Han, Chang;Wu, Tong
尽管单个mirna的作用和机制尚不完全清楚，但mirna最近与肝癌的发生有关。我们研究了miR-185在肝细胞癌（HCC）中的生物学功能和分子机制。与非肿瘤性肝实质相比，miR-185在人HCC组织中的表达降低。定量RT-PCR显示，与原代肝细胞相比，人HCC细胞中miR-185的表达减少。miR-185在人HCC细胞中的过表达抑制体外细胞增殖和侵袭，阻止SCID小鼠的肿瘤生长。miR-185过表达抑制肝癌细胞DNMT1 3'非翻译区荧光素酶报告细胞活性；当mir -185结合位点发生突变时，这种效应被消除。miR-185模拟或过表达降低HCC细胞中DNMT1蛋白水平。这些发现证实DNMT1是HCC细胞中miR-185的真正靶点。DNMT1过表达阻止了mir -185诱导的肝癌细胞增殖/侵袭的抑制，这一事实进一步支持了DNMT1在mir -185诱导的肝癌细胞生长抑制中的作用。miR-185模拟或过表达降低PTEN启动子DNA甲基化，增强PTEN表达，抑制Akt磷酸化；这些影响被DNMT1过表达部分逆转。这些结果提供了新的证据，证明miR-185通过靶向DNMT1抑制HCC细胞生长，导致PTEN诱导和Akt抑制。因此，再激活或诱导miR-185可能是HCC治疗的一种新的治疗策略。
miRNAs have recently been implicated in hepatocarcinogenesis, although the actions and mechanisms of individual miRNAs remain incompletely understood. We examined the biological functions and molecular mechanisms of miR-185 in hepatocellular carcinoma (HCC). The expression of miR-185 is decreased in human HCC tissues compared with the nonneoplastic Liver parenchyma. Quantitative RT-PCR showed a reduction of miR-185 in human HCC cells compared with primary hepatocytes. miR-185 overexpression in human HCC cells inhibited cell proliferation and invasion in vitro and prevented tumor growth in SCID mice. miR-185 overexpression inhibited DNMT1 3' untranslated region Luciferase reporter activity in HCC cells; this effect was abolished when the miR-185-binding site was mutated. miR-185 mimic or overexpression decreased the Level of DNMT1 protein in HCC cells. These findings establish DNMT1 as a bona fide target of miR-185 in HCC cells. The role of DNMT1 in miR-185-induced inhibition of HCC growth was further supported by the fact that DNMT1 overexpression prevented miR-185-induced inhibition of HCC cell proliferation/invasion. miR-185 mimic or overexpression reduced PTEN promoter DNA methylation and enhanced PTEN expression, Leading to the inhibition of Akt phosphorylation; these effects were partially reversed by DNMT1 overexpression. These results provide novel evidence that miR-185 inhibits HCC cell growth by targeting DNMT1, leading to PTEN induction and Akt inhibition. Thus, reactivation or induction of miR-185 may represent a novel therapeutic strategy for HCC treatment.