Super-enhancer-driven AJUBA is activated by TCF4 and involved in epithelial-mesenchymal transition in the progression of Hepatocellular Carcinoma
Super-enhancer-driven AJUBA is activated by TCF4 and involved in epithelial-mesenchymal transition in the progression of Hepatocellular Carcinoma
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超级增强子驱动的AJUBA被TCF4激活并参与肝细胞癌进展中的上皮间质转化
DOI：
10.7150/thno.45349
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发表时间：
2020
期刊：
影响因子：
12.4
通讯作者：
Xie Dan
中科院分区：
文献类型：
--
作者：
Zhang Chi;Wei Shi;Sun Wei-Peng;Teng Kai;Dai Miao-Miao;Wang Feng-Wei;Chen Jie-Wei;Ling Han;Ma Xiao-Dan;Feng Zi-Hao;Duan Jin-Ling;Cai Mu-Yan;Xie Dan
背景和目标：异常转录程序是一种高度调控的过程，在肝细胞癌（HCC）的发生和发展中起着重要作用。新出现的证据表明，超级增强子（SE）通常驱动关键的癌基因表达。然而，SE相关基因在HCC发病机制中的作用仍知之甚少。方法：我们对HCC细胞进行了整合ChIP-seq和Hi-C分析，并将ajuba LIM蛋白（AJUBA）鉴定为SE相关基因。我们使用免疫组织化学、免疫印迹和qRT-PCR评估了AJUBA在HCC中的表达。进行ChIP和荧光素酶报告基因测定以证明转录因子4（TCF 4）与Ajuba相关SE结合。然后，我们使用体外和体内试验评估了AjuBA在HCC中的作用。采用免疫荧光和免疫印迹法检测上皮-间质转化（EMT）。此外，我们使用免疫沉淀和BiFC测定来探索潜在的机制。结果：我们确定AJUBA作为SE相关的癌基因在HCC中由TCF 4调控。AJUBA高表达与HCC患者的侵袭性表型和不良结局相关。AJUBA基因敲除显著降低了细胞在体外和体内的迁移和侵袭能力。此外，AJUBA在HCC中的过表达募集了肿瘤坏死因子相关因子6（TRAF 6），增强了Akt的磷酸化，并增加了Akt对GSK-3β的活性，从而促进了EMT。结论：我们的研究结果提供了SE相关基因AJUBA和侵袭性HCC中肿瘤EMT之间的功能和机制联系。
Background and Aims: Aberrant transcriptional programs are highly regulated processes that play important roles in the development and progression of hepatocellular carcinoma (HCC). Emerging evidence suggests that super-enhancers (SEs) often drive critical oncogene expression. However, SE-associated genes in HCC pathogenesis are still poorly understood. Methods: We performed integrative ChIP-seq and Hi-C analyses of HCC cells and identified ajuba LIM protein (AJUBA) as a SE-associated gene. We evaluated AJUBA expression in HCC using immunohistochemistry, immunoblotting, and qRT-PCR. ChIP and luciferase reporter assays were performed to demonstrate that transcription factor 4 (TCF4) bound to AJUBA-associated SEs. We then assessed the role of AJUBA in HCC using both in vitro and in vivo assays. Epithelial-mesenchymal transition (EMT) was examined using immunofluorescence and immunoblotting assays. Furthermore, we used immunoprecipitation and BiFC assays to explore the underlying mechanisms. Results: We identified AJUBA as a SE-associated oncogene in HCC regulated by TCF4. High AJUBA expression was related to an aggressive phenotype and unfavorable outcome in HCC patients. AJUBA knockdown significantly reduced cell migration and invasion capacities both in vitro and in vivo. Furthermore, AJUBA overexpression in HCC recruited tumor necrosis factor associated factor 6 (TRAF6), enhancing the phosphorylation of Akt and increasing Akt activity toward GSK-3β, thus promoting EMT. Conclusions: Our results provide functional and mechanistic links between the SE-associated gene AJUBA and tumor EMT in aggressive HCC.