title: Downregulation of microRNA-200 in EBV-associated gastric carcinoma.
abstract: EBV-associated gastric carcinoma is a distinct gastric carcinoma subtype with characteristic morphologic features similar to those of cells that undergo epithelial-to-mesenchymal transition. The effect of microRNA abnormalities in carcinogenesis was investigated by measuring the expression of the epithelial-to-mesenchymal transition-related microRNAs, miR-200a and miR-200b, in 36 surgically resected gastric carcinomas using quantitative reverse transcription-PCR analysis. MiR-200 family expression was decreased in EBV-associated gastric carcinoma, as compared with that in EBV-negative carcinoma. Downregulation of the miR-200 family was found in gastric carcinoma cell lines infected with recombinant EBV (MKN74-EBV, MKN7-EBV, and NUGC3-EBV), accompanied by the loss of cell adhesion, reduction of E-cadherin expression, and upregulation of ZEB1 and ZEB2. E-cadherin expression was partially restored by transfection of EBV-infected cells with miR-200 family precursors. Reverse transcription-PCR analysis of primary precursors of miR-200 (pri-miR-200) revealed that the transcription of pri-miR-200 was decreased in EBV-infected cells. Transfection of MKN74 cells with BARF0, EBNA1, and LMP2A resulted in a decrease of pri-miR-200, whereas transfection with EBV-encoded small RNA (EBER) did not. These four latent genes contributed to the downregulation of the mature miR-200 family and the subsequent upregulation of ZEB1/ZEB2, resulting in the reduction of E-cadherin expression. These findings indicate that all the latency type I genes have a synergetic effect on the downregulation of the miR-200 family that leads to reduced E-cadherin expression, which is a crucial step in the carcinogenesis of EBV-associated gastric carcinoma.
authors.affiliation: Department of Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Shinozaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakatani
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Ushiku
authors.forename: Rumi
authors.initials: R
authors.lastname: Hino
authors.forename: Maya
authors.initials: M
authors.lastname: Isogai
authors.forename: Shunpei
authors.initials: S
authors.lastname: Ishikawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Uozaki
authors.forename: Kenzo
authors.initials: K
authors.lastname: Takada
authors.forename: Masashi
authors.initials: M
authors.lastname: Fukayama
mesh_terms: D015820:Cadherins / Q000096:biosynthesis / Q000235:genetics; D045744:Cell Line, Tumor; D015536:Down-Regulation; D020031:Epstein-Barr Virus Infections / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D015972:Gene Expression Regulation, Neoplastic; D015967:Gene Expression Regulation, Viral; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D035683:MicroRNAs / Q000096:biosynthesis / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000821:virology*; D014162:Transfection; D017735:Virus Latency
chemical_list: D015820:Cadherins; C533896:MIRN200 microRNA, human; D035683:MicroRNAs