Enhancer of Zeste Homolog 2 Silences MicroRNA-218 in Human Pancreatic Ductal Adenocarcinoma Cells by Inducing Formation of Heterochromatin
Enhancer of Zeste Homolog 2 Silences MicroRNA-218 in Human Pancreatic Ductal Adenocarcinoma Cells by Inducing Formation of Heterochromatin
复制标题
Zeste 同源物 2 的增强剂通过诱导异染色质的形成来沉默人胰腺导管腺癌细胞中的 MicroRNA-218
DOI：
10.1053/j.gastro.2013.01.058
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发表时间：
2013-05-01
期刊：
影响因子：
29.4
通讯作者：
Chen, Yangchao
中科院分区：
文献类型：
--
作者：
Li, Chi Han;To, Ka-Fai;Chen, Yangchao
背景与目的：zeste增强子同源物2（EZH 2）是一种组蛋白甲基转移酶，由胰腺导管腺癌（PDAC）细胞过表达，并增加其侵袭性。我们鉴定了由EZH 2调控的microRNA（miR），并研究了它们在PDAC细胞中的功能。方法：我们对与EZH 2抑制剂3-deazaneplanocin A孵育的PDAC细胞和过表达EZH 2的胰腺导管上皮细胞进行了miR谱分析。通过定量逆转录聚合酶链反应和免疫组化分析miR的表达水平和miR的靶点。我们表达了不同形式的EZH 2来分析功能结构域，并使用小干扰RNA来降低其在PDAC细胞中的水平。结果：miR-218在PDAC细胞中的表达被EZH 2抑制。与配对的相邻非肿瘤组织相比，原发性PDAC肿瘤样本中miR-218的水平显著降低。miR-218在SW 1990细胞中的过表达降低了其增殖以及裸鼠肿瘤的形成和转移。从SW 1990细胞中丢失miR-218增加UDP-糖基转移酶8的水平，并且发现miR-218结合其3 '-UTR。UDP-糖基转移酶蛋白和信使RNA的水平与PDAC细胞系的转移潜力和患者肿瘤的进展相关。发现EZH 2通过与其启动子结合，促进异染色质形成和募集DNA甲基转移酶1，3A和3B来沉默miR-218。结论：EZH 2在来自患者的PDAC样品中上调，并沉默miR-218。MicroRNA-218可防止培养的PDAC细胞增殖，以及裸鼠中的肿瘤生长和转移。MicroRNA-218降低UDP-糖基转移酶的水平，这与小鼠PDAC肿瘤的转移潜力和人类PDAC的进展有关。
BACKGROUND & AIMS: Enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase that is overexpressed by pancreatic ductal adenocarcinoma (PDAC) cells and increases their aggressiveness. We identified microRNAs (miRs) that are regulated by EZH2 and studied their functions in PDAC cells. METHODS: We performed miR profile analysis of PDAC cells incubated with EZH2 inhibitor 3-deazaneplanocin A, and pancreatic ductal epithelial cells that overexpressed EZH2. Expression levels of miRs and the targets of miRs were analyzed by quantitative reverse transcription polymerase chain reaction and immunohistochemistry. We expressed different forms of EZH2 to analyze functional domains and used small interfering RNAs to reduce its level in PDAC cells. RESULTS: Expression of miR-218 was repressed by EZH2 in PDAC cells. Levels of miR-218 were significantly reduced in primary PDAC tumor samples compared with paired, adjacent nontumor tissue. Overexpression of miR-218 in SW1990 cells reduced their proliferation and tumor formation and metastasis in nude mice. Loss of miR-218 from SW1990 cells increased levels of UDP-glycosyltransferase 8 and miR-218 was found to bind to its 3'-UTR. Levels of UDP-glycosyltransferase protein and messenger RNA were associated with the metastatic potential of PDAC cell lines and progression of tumors in patients. EZH2 was found to silence miR-218 by binding to its promoter, promoting heterochromatin formation, and recruiting the DNAs methyltransferase 1, 3A, and 3B. CONCLUSIONS: EZH2 is up-regulated in PDAC samples from patients and silences miR-218. MicroRNA-218 prevents proliferation of PDAC cells in culture, and tumor growth and metastasis in nude mice. MicroRNA-218 reduces levels of UDP-glycosyltransferase, which is associated with the metastatic potential of PDAC tumors in mice and progression of human PDAC.