Global histone modification profiling reveals the epigenomic dynamics during malignant transformation in a four-stage breast cancer model.
Global histone modification profiling reveals the epigenomic dynamics during malignant transformation in a four-stage breast cancer model.
复制标题
全局组蛋白修饰分析揭示了四阶段乳腺癌模型恶性转化过程中的表观基因组动态
DOI：
10.1186/s13148-016-0201-x
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发表时间：
2016
影响因子：
5.7
通讯作者：
Wu M
中科院分区：
文献类型：
--
作者：
Zhao QY;Lei PJ;Zhang X;Zheng JY;Wang HY;Zhao J;Li YM;Ye M;Li L;Wei G;Wu M
表观遗传调控已成为肿瘤发生和转移的关键步骤。近年来，多种组蛋白甲基转移酶和去甲基酶被认为是肿瘤抑制因子或癌基因。但癌细胞转化过程中的关键表观基因组事件仍知之甚少。
通过在原代乳腺上皮细胞中稳定表达三种癌基因，建立了一种乳腺癌转化模型。采用染色质免疫沉淀结合下一代组蛋白甲基化测序技术来确定转化过程中的表观遗传事件。利用蛋白质印迹法、定量逆转录聚合酶链反应和免疫染色来测定细胞和组织中的基因表达。
组蛋白H3K9me2和me3是两种转录抑制标记，在体外乳腺癌细胞模型和体内临床组织中均减少。对与H3K9甲基化相关的酶进行的一项调查表明，KDM3A/JMJD1A（一种H3K9me1和me2的去甲基酶）在癌症转化过程中逐渐增加，并且在患者组织中升高。KDM3A/JMJD1A缺失会损害裸鼠体内肿瘤和转化细胞系的生长。全基因组染色质免疫沉淀测序分析显示，减少的H3K9me2大片段有序染色质K9修饰（LOCKs）的边界富含癌症相关基因，如MYC和PAX3。进一步的研究表明，KDM3A/JMJD1A直接与这些癌基因结合，并通过去除H3K9me2标记来调节它们的转录。
我们的研究表明，组蛋白H3K9me2和me3的减少以及KDM3A/JMJD1A的升高是乳腺癌的重要事件，并阐明了乳腺癌转化过程中的动态表观基因组机制。
本文的网络版（doi:10.1186/s13148 - 016 - 0201 - x）包含补充材料，授权用户可获取。
BackgroundEpigenetic regulation has emerged to be the critical steps for tumorigenesis and metastasis. Multiple histone methyltransferase and demethylase have been implicated as tumor suppressors or oncogenes recently. But the key epigenomic events in cancer cell transformation still remain poorly understood.MethodsA breast cancer transformation model was established via stably expressing three oncogenes in primary breast epithelial cells. Chromatin immunoprecipitation followed by the next-generation sequencing of histone methylations was performed to determine epigenetic events during transformation. Western blot, quantitative RT-PCR, and immunostaining were used to determine gene expression in cells and tissues.ResultsHistones H3K9me2 and me3, two repressive marks of transcription, decrease in in vitro breast cancer cell model and in vivo clinical tissues. A survey of enzymes related with H3K9 methylation indicated that KDM3A/JMJD1A, a demethylase for H3K9me1 and me2, gradually increases during cancer transformation and is elevated in patient tissues. KDM3A/JMJD1A deficiency impairs the growth of tumors in nude mice and transformed cell lines. Genome-wide ChIP-seq analysis reveals that the boundaries of decreased H3K9me2 large organized chromatin K9 modifications (LOCKs) are enriched with cancer-related genes, such as MYC and PAX3. Further studies show that KDM3A/JMJD1A directly binds to these oncogenes and regulates their transcription by removing H3K9me2 mark.ConclusionsOur study demonstrates reduction of histones H3K9 me2 and me3, and elevation of KDM3A/JMJD1A as important events for breast cancer, and illustrates the dynamic epigenomic mechanisms during breast cancer transformation.