MicroRNA 345, a methylation-sensitive microRNA is involved in cell proliferation and invasion in human colorectal cancer
MicroRNA 345, a methylation-sensitive microRNA is involved in cell proliferation and invasion in human colorectal cancer
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MicroRNA 345是一种甲基化敏感的microRNA，参与人结直肠癌的细胞增殖和侵袭
DOI：
10.1093/carcin/bgr114
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发表时间：
2011-08-01
期刊：
影响因子：
4.7
通讯作者：
Fang, Jing-Yuan
中科院分区：
文献类型：
--
作者：
Tang, Jie-Ting;Wang, Ji-Lin;Fang, Jing-Yuan
异常甲基化已被证明在肿瘤发生过程中触发肿瘤抑制基因的失活。MicroRNAs（miRNAs）在结直肠癌（CRC）中表达异常，其中一些可能具有抑癌基因的功能。在这里，我们研究了CpG岛启动子超甲基化作为miRNA破坏的潜在机制，并鉴定了可能抑制CRC发展的甲基化敏感性miRNA。我们使用微阵列比较了5-氮杂-2 '-脱氧胞苷（5-aza-dC）处理后miRNA的差异表达。分析候选miRNA的DNA甲基化状态。将候选miRNA转染到CRC细胞中并探索其生长抑制机制。采用荧光素酶报告基因分析和western blot鉴定候选miRNA的靶基因。经5-aza-dC处理后，mir-345的表达明显增加。mir-345的DNA甲基化分析显示肿瘤中的甲基化水平高于正常组织。51.6%的结直肠癌组织中mir-345的表达明显低于相应的癌旁组织。mir-345的低表达与淋巴结转移和组织学类型有关。增加的mir-345功能足以在体外抑制结肠癌细胞增殖和侵袭。此外，我们确定BCL 2相关的athanogene 3（BAG 3），一种抗凋亡蛋白，是mir-345的靶点。这些结果表明，作为甲基化敏感的miRNA，mir-345可能在CRC的发生发展中发挥重要作用，作为一种生长抑制剂。
Aberrant methylation has been shown to trigger the inactivation of tumor suppressor genes during tumorigenesis. MicroRNAs (miRNAs) have been found deregulated in human colorectal cancer (CRC), and some of them may function as tumor suppressor genes. Here, we investigated CpG island promoter hypermethylation as a potential mechanism underlying miRNA disruption and identifed methylation-sensitive miRNAs that might repress CRC development. We compared differential expression of miRNAs after 5-aza-2'-deoxycitidine (5-aza-dC) treatment using microarrays. DNA methylation status of the candidate miRNA was analyzed. The candidate miRNA was transfected into CRC cells and growth-suppressive mechanisms were explored. Luciferase reporter assay and western blot were used to identify the target genes of the candidate miRNA. The expression of mir-345 was significantly increased after 5-aza-dC treatment. DNA methylation analyses of mir-345 showed high methylation levels in tumor versus normal tissues. Expression of mir-345 was significantly down-regulated in 51.6% of CRC tissues compared with corresponding non-cancerous tissues. Low expression of mir-345 was associated with lymph node metastasis and worse histological type. Increased mir-345 function was sufficient to suppress colon cancer cell proliferation and invasiveness in vitro. Furthermore, we identified BCL2-associated athanogene 3 (BAG3), an anti-apoptosis protein, to be a target of mir-345. These results suggested as a methylation-sensitive miRNA in CRC, mir-345 may play an important role of antineoplastic as a growth inhibitor in the development of CRC.