DNA-methylation-mediated silencing of miR-7-5p promotes gastric cancer stem cell invasion via increasing Smo and Hes1
DNA-methylation-mediated silencing of miR-7-5p promotes gastric cancer stem cell invasion via increasing Smo and Hes1
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DNA甲基化介导的miR-7-5p沉默通过增加Smo和Hes1促进胃癌干细胞侵袭
DOI：
10.1002/jcp.29168
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发表时间：
2019-09-13
影响因子：
5.6
通讯作者：
Zhang, Hou-Ting
中科院分区：
文献类型：
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作者：
Xin, Lin;Liu, Li;Zhang, Hou-Ting
癌症干细胞是具有自我更新能力、高致瘤活性和多谱系分化潜能的未分化癌细胞。microRNA在肿瘤发生过程中调节基因表达起着关键作用。在这里，我们研究了miR-7的作用及其在胃癌干细胞（GCSC）中失调的机制。使用干细胞标记物CD 44通过荧光激活细胞分选来分选GCSC。结果表明，CD 44（+）细胞比CD 44（-）细胞具有更强的侵袭力，形成的球形集落数量更多。实时荧光定量PCR结果显示，miR-7- 5 p在GCSC中表达显著下调，但在去甲硫氨酸培养基中表达显著增加。使用甲基化特异性PCR，miR-7- 5 p的下调是由于启动子区域的DNA甲基化增加。过表达miR-7- 5 p可通过靶向Smo和Hes 1，抑制Notch和Hedgehog信号通路，减少GCSC集落形成，降低GCSC的侵袭能力。值得注意的是，上调miR-7- 5 p抑制了异种移植模型中肿瘤的生长。因此，这些数据表明miR-7- 5 p通过抑制Smo和Hes 1抑制GCSC侵袭，这为胃癌治疗提供了潜在的治疗靶点。
Cancer stem cells are undifferentiated cancer cells that have self-renewal ability, a high tumorigenic activity, and a multilineage differentiation potential. MicroRNAs play a critical role in regulating gene expression during carcinogenesis. Here, we investigated the role of miR-7 and the mechanism by which it is dysregulated in gastric cancer stem cells (GCSCs). The stem cell marker, CD44, was used to sort GCSCs by fluorescence-activated cell sorting. We found that CD44 (+) cells have higher invasiveness and form more number of sphere colonies than CD44 (-) cells. Quantitative real-time polymerase chain reaction (PCR) revealed that the miR-7-5p expression was remarkably downregulated in GCSCs but was significantly increased in the methionine-deprived medium. The downregulation of miR-7-5p results from the increased DNA methylation in the promoter region using the methylation-specific PCR. Overexpression of miR-7-5p reduced the formation of colony and decreased the invasion of GCSCs through targeting Smo and Hes1 and subsequent repressing Notch and Hedgehog signaling pathways in vitro. Notably, upregulating miR-7-5p inhibited the growth of tumor in the xenograft model. Hence, these data demonstrated that miR-7-5p represses GCSC invasion through inhibition of Smo and Hes1, which provides a potential therapeutic target of gastric cancer treatment.