Hepatitis B virus promotes β-catenin-signalling and disassembly of adherens junctions in a Src kinase dependent fashion

// Gesa von Olshausen 1 , Maria Quasdorff 2, 3 , Romina Bester 4 , Silke Arzberger 2, 4 , Chunkyu Ko 4 , Maarten van de Klundert 4 , Ke Zhang 4 , Margarete Odenthal 5, 6 , Marc Ringelhan 4, 7 , Carien M. Niessen 6, 8, 9 and Ulrike Protzer 4, 10 1 Department of Internal Medicine I, University Hospital rechts der Isar, Technical University of Munich, Munich, Germany 2 Molecular Infectiology, Institute for Medical Micro biology, Immunology and Hygiene, University Hospital Cologne, Cologne, Germany 3 Department of Gastroenterology and Hepatology, University Hospital Cologne, Cologne, Germany 4 Institute of Virology, Technical University of Munich/Helmholtz Zentrum Munchen, Munich, Germany 5 Institute of Pathology, University Hospital Cologne, Cologne, Germany 6 Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany 7 Department of Internal Medicine II, University Hospital rechts der Isar, Technical University of Munich, Munich, Germany 8 Department of Dermatology, University Hospital of Cologne, Cologne, Germany 9 Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany 10 German Center for Infection Research (DZIF), Munich Partner Site, Munich, Germany Correspondence to: Ulrike Protzer, email: protzer@tum.de Carien M. Niessen, email: carien.niessen@uni-koeln.de Keywords: hepatitis B virus (HBV); hepatocellular carcinoma (HCC); β-catenin; Src kinase; E-cadherin Received: April 10, 2018      Accepted: August 27, 2018      Published: September 21, 2018 ABSTRACT Hepatitis B virus (HBV) infection is a prominent cause of hepatocellular carcinoma (HCC) but the underlying molecular mechanisms are complex and multiple pathways have been proposed such as the activation of the Wnt-/β-catenin-signalling and dysregulation of E-cadherin/β-catenin adherens junctions. This study aimed to identify mechanisms of how HBV infection and replication as well as HBV X protein (HBx) gene expression in the context of an HBV genome influence Wnt-/β-catenin-signalling and formation of adherens junctions and to which extent HBx contributes to this. Regulation of E-cadherin/β-catenin junctions and β-catenin-signalling as well as the role of HBx were investigated using constructs transiently or stably inducing replication of HBV+/-HBx in hepatoma cell lines. In addition, HCC and adjacent non-tumorous tissue samples from HBV-infected HCC patients and drug interference in HBV-infected cells were studied. Although HBV did not alter overall expression levels of E-cadherin or β-catenin, it diminished their cell surface localization resulting in nuclear translocation of β-catenin and activation of its target genes. In addition, HBV gene expression increased the amount of phosphorylated c-Src kinase. Treatment with Src kinase inhibitor Dasatinib reduced HBV replication, prevented adherens junction disassembly and reduced β-catenin-signalling, while Sorafenib only did so in cells with mutated β-catenin. Interestingly, none of the HBV induced alterations required HBx. Thus, HBV stimulated β-catenin-signalling and induced disassembly of adherens junctions independently of HBx through Src kinase activation. These pathways may contribute to hepatocellular carcinogenesis and seem to be more efficiently inhibited by Dasatinib than by Sorafenib.