Saravana Kumar Kailasam Mani1, Hao Zhang1, Ahmed Diab1, Pete E Pascuzzi2, Lydie Lefrançois3, Nadim Fares3, Brigitte Bancel3, Philippe Merle3, Ourania Andrisani4. 1. Department of Basic Medical Sciences, Purdue University, West Lafayette, IN 47907, United States; Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, United States. 2. Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, United States; Purdue University Libraries, Purdue University, West Lafayette, IN 47907, United States. 3. Centre de Recherche en Cancérologie de Lyon, UMR INSERM 1052 - CNRS 5286, Lyon Cedex 03, France. 4. Department of Basic Medical Sciences, Purdue University, West Lafayette, IN 47907, United States; Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, United States. Electronic address: andrisao@purdue.edu.
Abstract
BACKGROUND & AIMS: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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. LAY SUMMARY: 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.
BACKGROUND & AIMS: 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. METHODS: 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-mycmice and chronically HBV infectedpatients. RESULTS: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. CONCLUSIONS: 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. LAY SUMMARY: 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.
Authors: Joan Fernando; Andrea Malfettone; Edgar B Cepeda; Roser Vilarrasa-Blasi; Esther Bertran; Giulia Raimondi; Àngels Fabra; Alberto Alvarez-Barrientos; Pedro Fernández-Salguero; Conrado M Fernández-Rodríguez; Gianluigi Giannelli; Patricia Sancho; Isabel Fabregat Journal: Int J Cancer Date: 2014-08-04 Impact factor: 7.396
Authors: Ana De Jesus-Acosta; Daniel Laheru; Anirban Maitra; John Arcaroli; Michelle A Rudek; Arvind Dasari; Patrick J Blatchford; Kevin Quackenbush; Wells Messersmith Journal: Invest New Drugs Date: 2014-03-27 Impact factor: 3.850