EpCAM-regulated intramembrane proteolysis induces a cancer stem cell-like gene signature in hepatitis B virus-infected hepatocytes.
EpCAM-regulated intramembrane proteolysis induces a cancer stem cell-like gene signature in hepatitis B virus-infected hepatocytes.
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DOI：
10.1016/j.jhep.2016.05.022
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发表时间：
2016-11
影响因子：
25.7
通讯作者：
Andrisani O
中科院分区：
文献类型：
--
作者：
Mani SK;Zhang H;Diab A;Pascuzzi PE;Lefrançois L;Fares N;Bancel B;Merle P;Andrisani O
B肝炎病毒（HBV）复制的肝细胞表现出染色质修饰多梳抑制复合物2（PRC 2）的丢失，导致特异性细胞PRC 2抑制基因的重新表达。上皮细胞粘附分子（EpCAM）是PRC 2抑制的基因，通常在肝祖细胞中表达，但在肝癌干细胞（hCSCs）中重新表达。在此，我们研究了EpCAM再表达在HBV介导的肝癌发生中的功能意义。采用分子方法（转染、荧光激活细胞分选、免疫印迹、qRT-PCR），我们研究了EpCAM调节的膜内蛋白水解（RIP）在体外HBV复制细胞中以及在来自HBV X/c-myc小鼠和慢性HBV感染患者的肝肿瘤中的作用。EpCAM在HBV复制细胞中经历RIP，激活经典Wnt信号传导。转染表达绿色荧光蛋白（GFP）的Wnt应答质粒鉴定了HBV复制细胞的GFP +群体。这些GFP+/Wnt+细胞表现出类似于hCSC的顺铂和索拉非尼抗性生长，并且多能性基因NANOG、OCT 4、S 0X 2和hCSC标志物BAMBI、CD 44和CD 133的表达增加。这些基因被称为EpCAM RIP和Wnt诱导的hCSC样基因签名。有趣的是，这种基因特征也在X/c-myc双转基因小鼠的肝肿瘤中过表达。在临床上，一组HBV相关的肝细胞癌被鉴定，表现出hCSC样基因标签的表达升高，并与手术切除后总生存率降低相关。hCSC样基因标记为HBV诱导的HCC亚型分类提供了预后工具。由于EpCAM RIP和Wnt信号传导驱动这种hCSC样特征的表达，因此可以探索这些途径的抑制作为这种HBV相关HCC亚型的治疗策略。在这项研究中，我们提供了证据的分子机制，慢性感染的B型肝炎病毒的结果在发展中的预后不良肝癌。基于这种机制，我们的研究结果表明可能的治疗干预。
Hepatocytes in which the hepatitis B virus (HBV) is replicating exhibit loss of the chromatin modifying polycomb repressive complex 2 (PRC2), resulting in re-expression of specific, cellular PRC2-repressed genes. Epithelial cell adhesion molecule (EpCAM) is a PRC2-repressed gene, normally expressed in hepatic progenitors, but re-expressed in hepatic cancer stem cells (hCSCs). Herein, we investigated the functional significance of EpCAM re-expression in HBV-mediated hepatocarcinogenesis. Employing molecular approaches (transfections, fluorescence-activated cell sorting, immunoblotting, qRT-PCR), we investigated the role of EpCAM-regulated intramembrane proteolysis (RIP) in HBV replicating cells in vitro, and in liver tumors from HBV X/c-myc mice and chronically HBV infected patients. EpCAM undergoes RIP in HBV replicating cells, activating canonical Wnt signaling. Transfection of Wnt-responsive plasmid expressing green fluorescent protein (GFP) identified a GFP + population of HBV replicating cells. These GFP+/Wnt+ cells exhibited cisplatin- and sorafenib-resistant growth resembling hCSCs, and increased expression of pluripotency genes NANOG, OCT4, SOX2, and hCSC markers BAMBI, CD44 and CD133. These genes are referred as EpCAM RIP and Wnt-induced hCSC-like gene signature. Interestingly, this gene signature is also overexpressed in liver tumors of X/c-myc bitransgenic mice. Clinically, a group of HBV-associated hepatocellular carcinomas was identified, exhibiting elevated expression of the hCSC-like gene signature and associated with reduced overall survival post-surgical resection. The hCSC-like gene signature offers promise as prognostic tool for classifying subtypes of HBV-induced HCCs. Since EpCAM RIP and Wnt signaling drive expression of this hCSC-like signature, inhibition of these pathways can be explored as therapeutic strategy for this subtype of HBV-associated HCCs. In this study, we provide evidence for a molecular mechanism by which chronic infection by the hepatitis B virus results in the development of poor prognosis liver cancer. Based on this mechanism our results suggest possible therapeutic interventions.