title: Epstein-Barr virus BARF1-induced NFκB/miR-146a/SMAD4 alterations in stomach cancer cells.
abstract: Epstein-Barr virus (EBV)-encoded BamHI-A rightward frame 1 (BARF1) is a putative viral oncogene in EBV-infected stomach cancer. The aim of the present study was to investigate BARF1-induced cellular protein and microRNA alterations. In this study, BARF1-expressing stomach cancer cells showed a high rate of proliferation, high levels of NFκB, and miR-146a upregulation, which was reversed by NFκB knockdown. During BARF1-induced NFκB upregulation, hCSF1 receptor level was unchanged. Knockdown of BARF1 in the naturally EBV-infected YCCEL1 stomach cancer cells suppressed cell proliferation, and downregulated NFκB and miR-146a. SMAD4 was identified as a miR-146a target and was downregulated in BARF1-expressing cells, whereas SMAD4 expression was restored by anti-miR-146a. Knockdown of BARF1 in YCCEL1 cells upregulated SMAD4, and this effect was reversed by miR-146a overexpression. Transfection of BARF1-expressing cells with pCEP4-SMAD4 abolished the cell proliferating effect of BARF1. In stomach cancer tissues, miR-146a was expressed at higher levels, and more frequent NFκB nuclear positivity immunohistochemically, but not of SMAD4 nuclear loss was found in the EBV-positive group compared with the EBV-negative group. In conclusion, EBV-encoded BARF1 promotes cell proliferation in stomach cancer by upregulating NFκB and miR-146a and downregulating SMAD4, thereby contributing to EBV-induced stomach cancer progression.
authors.affiliation: Asan Institute for Life Sciences, Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.|Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Dong Ha
authors.initials: DH
authors.lastname: Kim
authors.affiliation: Department of Pathology, Seoul National University Boramae Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Mee Soo
authors.initials: MS
authors.lastname: Chang
authors.affiliation: Asan Institute for Life Sciences, Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.|Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Chan Jin
authors.initials: CJ
authors.lastname: Yoon
authors.affiliation: Department of Pathology, VU University Medical Center, Amsterdam, the Netherlands.
authors.forename: Jaap M
authors.initials: JM
authors.lastname: Middeldorp
authors.affiliation: Department of Surgery/Division of Abdominal Transplantation, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Olivia M
authors.initials: OM
authors.lastname: Martinez
authors.affiliation: Department of Pathology, Seoul National University Boramae Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Sun-Ju
authors.initials: SJ
authors.lastname: Byeon
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Rha
authors.affiliation: Asan Institute for Life Sciences, Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.|Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Sung Han
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Asan Institute for Life Sciences, Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.|Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Yang Soo
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Asan Institute for Life Sciences, Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.|Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Jun Hee
authors.initials: JH
authors.lastname: Woo
mesh_terms: D045744:Cell Line, Tumor; D049109:Cell Proliferation; D018450:Disease Progression; D015972:Gene Expression Regulation, Neoplastic; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D015398:Signal Transduction; D051901:Smad4 Protein / Q000235:genetics / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000821:virology; D013997:Time Factors; D014162:Transfection; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C086495:BARF1 protein, Human herpesvirus 4; C542542:MIRN146 microRNA, human; D035683:MicroRNAs; D016328:NF-kappa B; C497796:SMAD4 protein, human; D051901:Smad4 Protein; D014764:Viral Proteins
keywords: BARF1; Epstein-Barr virus; NFκB; SMAD4; miR-146a