Hepatitis B virus PreS2-mutant large surface antigen activates store-operated calcium entry and promotes chromosome instability.

// Tim Ting-Chung Yen 1 , Anderson Yang 1 , Wen-Tai Chiu 2, 3 , Tian-Neng Li 1 , Lyu-Han Wang 1 , Yi-Hsuan Wu 1 , Hui-Chen Wang 4 , Linyi Chen 5, 6 , Wen-Ching Wang 1 , Wenya Huang 7 , Chien-Wen Chang 8 , Margaret Dah-Tsyr Chang 1, 6 , Meng-Ru Shen 3, 9 , Ih-Jen Su 3, 10, 11 , Lily Hui-Ching Wang 1, 6 1 Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu 300, Taiwan 2 Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan 3 Center of Infectious Diseases and Signal Transduction, National Cheng Kung University, Tainan 701, Taiwan 4 Institute of Pharmaceutics, Development Center for Biotechnology, Taipei 22180, Taiwan 5 Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 300, Taiwan 6 Department of Medical Science, National Tsing Hua University, Hsinchu 300, Taiwan 7 Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan 8 Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 300, Taiwan 9 Department of Pharmacology, National Cheng Kung University, Tainan 701, Taiwan 10 National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan 704, Taiwan 11 Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan 710, Taiwan Correspondence to: Lily Hui-Ching Wang, e-mail: lilywang@life.nthu.edu.tw Ih-Jen Su, e-mail: suihjen0704@stust.edu.tw Keywords: SOCE, ER stress, hepatitis B virus, ground-glass hepatocytes, aneuploidy Received: August 21, 2015      Accepted: February 28, 2016      Published: March 16, 2016 ABSTRACT Hepatitis B virus (HBV) is a driver of hepatocellular carcinoma, and two viral products, X and large surface antigen (LHBS), are viral oncoproteins. During chronic viral infection, immune-escape mutants on the preS2 region of LHBS (preS2-LHBS) are gain-of-function mutations that are linked to preneoplastic ground glass hepatocytes (GGHs) and early disease onset of hepatocellular carcinoma. Here, we show that preS2-LHBS provoked calcium release from the endoplasmic reticulum (ER) and triggered stored-operated calcium entry (SOCE). The activation of SOCE increased ER and plasma membrane (PM) connections, which was linked by ER- resident stromal interaction molecule-1 (STIM1) protein and PM-resident calcium release- activated calcium modulator 1 (Orai1). Persistent activation of SOCE induced centrosome overduplication, aberrant multipolar division, chromosome aneuploidy, anchorage-independent growth, and xenograft tumorigenesis in hepatocytes expressing preS2- LHBS. Chemical inhibitions of SOCE machinery and silencing of STIM1 significantly reduced centrosome numbers, multipolar division, and xenograft tumorigenesis induced by preS2-LHBS. These results provide the first mechanistic link between calcium homeostasis and chromosome instability in hepatocytes carrying preS2-LHBS. Therefore, persistent activation of SOCE represents a novel pathological mechanism in HBV-mediated hepatocarcinogenesis.