title: Hepatitis B virus X protein upregulates DNA methyltransferase 3A/3B and enhances SOCS-1CpG island methylation.
abstract: The aim of the present study was to investigate the effect of hepatitis B virus X protein (HBx) on the expression of DNA methyltransferase (DNMT)3A/3B and suppressors of cytokine signaling‑1 (SOCS‑1), as well as promoter CpG island methylation of the SOCS‑1 gene. Stable hepatocyte cell lines expressing the HBx gene (pcDNA‑X/QSG7701) or an empty gene (pcDNA3.0/QSG7701) were established. Reverse transcription quantitative polymerase chain reaction (PCR) was used to detect the mRNA expression levels of DNMT3A/3B and SOCS‑1. Immunohistochemistry was used to detect the protein expression of DNMT3A/3B. Methylation‑specific PCR (MSP) was used to detect the methylation status of the SOCS‑1 gene promoter. The mRNA and protein expression levels of DNMT3A/3B were significantly higher in the pcDNA‑X/QSG7701‑transfected cells, compared with those in the pcDNA3.0/QSG7701 or non‑transfected QSG7701 cells (P<0.05), whereas the relative mRNA expression of SOCS‑1 was significantly lower in the pcDNA‑X/QSG7701 cells compared with the pcDNA3.0/QSG7701 and non‑transfected QSG7701 cells (F=19.6; P<0.05). Western blot analysis showed that the protein expression of SOCS‑1 was significantly lower in the pcDNA‑X/QSG7701 cells, compared with the pcDNA3.0/QSG7701 or non‑transfected QSG7701 cells (F=19.4; P<0.05). The results of the MSP analysis showed that SOCS‑1 promoter region methylation was present only in the pcDNA‑X/QSG7701 cells. The HBV‑X gene upregulated the mRNA and protein expression levels of DNMT3A/3B, downregulated the expression of SOCS‑1 and increased SOCS‑1 gene promoter CpG island methylation. This may provide a potential explanation of the mechanism underlying HBx-associated hepatocellular carcinoma.
authors.affiliation: Department of Infectious Disease, Key Laboratory of Viral Hepatitis of Hunan, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Fu
authors.affiliation: Department of Infectious Disease, East of People's Hospital, Linyi, Shandong 276034, P.R. China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Song
authors.affiliation: Department of Infectious Disease, The Eighth People's Hospital of Nanchang, Nanchang, Jiangxi 330008, P.R. China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Infectious Disease, Key Laboratory of Viral Hepatitis of Hunan, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China.
authors.forename: Deming
authors.initials: D
authors.lastname: Tan
authors.affiliation: Department of Infectious Disease, Key Laboratory of Viral Hepatitis of Hunan, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China.
authors.forename: Guozhen
authors.initials: G
authors.lastname: Liu
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D018899:CpG Islands / Q000235:genetics*; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation / Q000235:genetics*; D000090205:DNA Methyltransferase 3A; D006801:Humans; D007150:Immunohistochemistry; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics* / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D014162:Transfection; D015854:Up-Regulation / Q000235:genetics*; D054334:Viral Regulatory and Accessory Proteins; D000097584:DNA Methyltransferase 3B
chemical_list: D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; D012333:RNA, Messenger; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; D000097584:DNA Methyltransferase 3B; C000717967:DNMT3A protein, human; C108944:SOCS1 protein, human; C057628:hepatitis B virus X protein