The histone methyltransferase WHSC1 is regulated by EZH2 and is important for ovarian clear cell carcinoma cell proliferation
The histone methyltransferase WHSC1 is regulated by EZH2 and is important for ovarian clear cell carcinoma cell proliferation
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DOI：
10.1186/s12885-019-5638-9
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发表时间：
2019-05-15
期刊：
影响因子：
3.8
通讯作者：
Fujii, Tomoyuki
中科院分区：
文献类型：
--
作者：
Kojima, Machiko;Sone, Kenbun;Fujii, Tomoyuki
Wolf-Hirschhorn综合征候选基因-1(WHSC1)是一种组蛋白甲基转移酶，已被发现在多种肿瘤中表达上调，并与ZEST同源增强子2(EZH2)的表达相关。本研究旨在探讨WHSC1在卵巢透明细胞癌中的作用及其治疗意义。方法首先，采用定量聚合酶链式反应和免疫组织化学方法检测23例卵巢透明细胞癌标本中WHSC1的表达。其次，siRNA介导的WHSC1基因被敲除后，通过四甲基偶氮唑盐比色法检测WHSC1在OCCC细胞增殖中的作用。我们还进行了流式细胞术(FACS)来研究WHSC1对细胞周期的影响。为了研究EZH2和WHSC1之间的功能关系，我们利用siRNAs敲除了EZH2，并检测了WHSC1及其组蛋白标记H3K36m2在OCCC细胞中的表达水平。结果定量聚合酶链式反应和免疫组织化学检测结果显示，卵巢癌组织中WHSC1的表达显著高于正常卵巢组织。四甲基偶氮唑盐比色法显示WHSC1基因敲除可抑制细胞增殖，免疫印迹法检测到H3K36me2表达水平降低。流式细胞仪显示WHSC1基因敲除对细胞周期有影响。我们还证实了WHSC1的表达受到EZH2基因敲除或抑制的抑制，表明EZH2在OCCC细胞中位于WHSC1的上游。结论WHSC1的过表达诱导细胞生长，其表达至少部分受EZH2的调控。进一步的功能分析将揭示WHSC1是否是OCCC的一个有前途的治疗靶点。
BackgroundWolf-Hirschhorn syndrome candidate gene-1 (WHSC1), a histone methyltransferase, has been found to be upregulated and its expression to be correlated with expression of enhancer of zeste homolog 2 (EZH2) in several cancers. In this study, we evaluated the role of WHSC1 and its therapeutic significance in ovarian clear cell carcinoma (OCCC).MethodsFirst, we analyzed WHSC1 expression by quantitative PCR and immunohistochemistry using 23 clinical OCCC specimens. Second, the involvement of WHSC1 in OCCC cell proliferation was evaluated by MTT assays after siRNA-mediated WHSC1 knockdown. We also performed flow cytometry (FACS) to address the effect of WHSC1 on cell cycle. To examine the functional relationship between EZH2 and WHSC1, we knocked down EZH2 using siRNAs and checked the expression levels of WHSC1 and its histone mark H3K36m2 in OCCC cell lines. Finally, we checked WHSC1 expression after treatment with the selective inhibitor, GSK126.ResultsBoth quantitative PCR and immunohistochemical analysis revealed that WHSC1 was significantly overexpressed in OCCC tissues compared with that in normal ovarian tissues. MTT assay revealed that knockdown of WHSC1 suppressed cell proliferation, and H3K36me2 levels were found to be decreased in immunoblotting. FACS revealed that WHSC1 knockdown affected the cell cycle. We also confirmed that WHSC1 expression was suppressed by EZH2 knockdown or inhibition, indicating that EZH2 is upstream of WHSC1 in OCCC cells.ConclusionsWHSC1 overexpression induced cell growth and its expression is, at least in part, regulated by EZH2. Further functional analysis will reveal whether WHSC1 is a promising therapeutic target for OCCC.