MicroRNA-152 targets DNA methyltransferase 1 in NiS-transformed cells via a feedback mechanism
MicroRNA-152 targets DNA methyltransferase 1 in NiS-transformed cells via a feedback mechanism
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MicroRNA-152 通过反馈机制靶向 NiS 转化细胞中的 DNA 甲基转移酶 1
DOI：
10.1093/carcin/bgs343
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发表时间：
2013-02-01
期刊：
影响因子：
4.7
通讯作者：
Zeng, Guohua
中科院分区：
文献类型：
--
作者：
Ji, Weidong;Yang, Lei;Zeng, Guohua
镍（Ni）化合物是公认的人类致癌物，然而它们导致人类癌症的分子机制仍未被充分了解。微小RNA（miRNAs）是一类小的非编码RNA，参与多种生物学功能和致癌过程。在先前的研究中，我们发现硫化镍（NiS）转化的人支气管上皮（16HBE）细胞中DNA甲基转移酶1（DNMT1）表达上调。在此，我们研究了在NiS转化的细胞中是否某些miRNAs异常表达并以DNMT1为靶点。我们的结果显示，miRNA - 152（miR - 152）的表达通过启动子DNA高甲基化在NiS转化的细胞中特异性下调，而在NiS转化的细胞中异位表达miR - 152导致DNMT1表达显著降低。进一步的实验表明，miR - 152通过靶向其转录本的3'非翻译区直接下调DNMT1的表达。有趣的是，使用DNMT抑制剂5 - 氮杂 - 2 - 脱氧胞苷处理，或去除DNMT1，通过逆转启动子高甲基化以及DNMT1和MeCP2与NiS转化细胞中miR - 152启动子的结合，导致miR - 152表达增加。此外，在16HBE细胞中抑制miR - 152的表达会增加DNMT1的表达，并导致DNA甲基化增加，以及DNMT1和MeCP2与miR - 152启动子的结合增加，这表明miR - 152和DNMT1之间的相互作用是由一个双负反馈回路调控的。再者，在NiS转化的细胞中异位表达miR - 152导致细胞生长显著减少。相反，在16HBE细胞中抑制miR - 152的表达则显著增加细胞生长。综上所述，这些观察结果表明，通过一个涉及NiS诱导的恶性转化的反馈回路，miR - 152和DNMT1之间存在关键的功能性相互作用。
Nickel (Ni) compounds are well-recognized human carcinogens, yet the molecular mechanisms by which they cause human cancer are still not well understood. MicroRNAs (miRNAs), which are small non-coding RNAs, are involved in diverse biological functions and carcinogenesis. In previous study, we identified upregulation of DNA methyltransferase 1 (DNMT1) expression in nickel sulfide (NiS)-transformed human bronchial epithelial (16HBE) cells. Here, we investigated whether some miRNAs are aberrantly expressed and targets DNMT1 in NiS-transformed cells. Our results showed that the expression of miRNA-152 (miR-152) was specifically downregulated in NiS-transformed cells via promoter DNA hypermethylation, whereas ectopic expression of miR-152 in NiS-transformed cells resulted in a marked reduction of DNMT1 expression. Further experiments revealed that miR-152 directly downregulated DNMT1 expression by targeting the 3' untranslated regions of its transcript. Interestingly, treatment of DNMT inhibitor, 5-aza-2-deoxycytidine, or depletion of DNMT1 led to increased miR-152 expression by reversion of promoter hypermethylation, DNMT1 and MeCP2 binding to miR-152 promoter in NiS-transformed cells. Moreover, inhibition of miR-152 expression in 16HBE cells could increase DNMT1 expression and result in an increase in DNA methylation, DNMT1 and MeCP2 binding to miR-152 promoter, indicating an interaction between miR-152 and DNMT1 is regulated by a double-negative circuit. Furthermore, ectopic expression of miR-152 in NiS-transformed cells led to a significant decrease of cell growth. Conversely, inhibition of miR-152 expression in 16HBE cells significantly increased cell growth. Taken together, these observations demonstrate a crucial functional crosstalk between miR-152 and the DNMT1 via a feedback loop involved in NiS-induced malignant transformation.