title: HBV polymerase overexpression due to large core gene deletion enhances hepatoma cell growth by binding inhibition of microRNA-100.
abstract: Different types of hepatitis B virus (HBV) core gene deletion mutants were identified in chronic hepatitis B patients. However, their clinical roles in different stages of natural chronic HBV infection remained unclear. To address this issue, HBV core genes were sequenced in three gender- and age-matched patient groups diagnosed as chronic hepatitis, cirrhosis and hepatocellular carcinoma (HCC), respectively. Functional analysis of the identified mutants was performed. A novel type of large-fragment core gene deletion (LFCD) was identified exclusively in HCC patients and significantly associated with unfavorable postoperative survival. The presence of LFCDs resulted in generation of precore-polymerase fusion protein or brought the polymerase reading frame under direct control of HBV precore/core promoter, leading to its over-expression. Enhanced cell proliferation and increased tumorigenicity in nude mice were found in hepatoma cells expressing LFCDs. Because of the epsilon-binding ability of HBV polymerase, we hypothesized that the over-expressed polymerase carrying aberrant amino-terminal sequence could bind to cellular microRNAs. Screening of a panel of microRNAs revealed physical association of a precore-polymerase fusion protein with microRNA-100. A binding inhibition effect on microRNA-100 by the precore-polymerase fusion protein with up-regulation of its target, polo-like kinase 1 (PLK1), was discovered. The binding inhibition and growth promoting effects could be reversed by overexpressing microRNA-100. Together, HCC patients carrying hepatitis B large-fragment core gene deletion mutants had an unfavorable postoperative prognosis. The growth promoting effect was partly due to polymerase overexpression, leading to binding inhibition of microRNA-100 and up-regulation of PLK1.
authors.affiliation: Liver Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan.|Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Ya-Hui
authors.initials: YH
authors.lastname: Huang
authors.affiliation: Liver Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan.|Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Ying-Hsin
authors.initials: YH
authors.lastname: Tseng
authors.affiliation: Liver Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan.|Department of Hepato-Gastroenterology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
authors.forename: Wey-Ran
authors.initials: WR
authors.lastname: Lin
authors.affiliation: Department of Molecular Biology, Princeton University, NJ, USA.
authors.forename: George
authors.initials: G
authors.lastname: Hung
authors.affiliation: Department of Pathology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
authors.forename: Tse-Ching
authors.initials: TC
authors.lastname: Chen
authors.affiliation: Department of Pathology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
authors.forename: Tong-Hong
authors.initials: TH
authors.lastname: Wang
authors.affiliation: Division of Liver and Transplantation Surgery, Department of General Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
authors.forename: Wei-Chen
authors.initials: WC
authors.lastname: Lee
authors.affiliation: Liver Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan.|Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Chau-Ting
authors.initials: CT
authors.lastname: Yeh
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000473:pathology* / Q000821:virology; D018797:Cell Cycle Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000235:genetics; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D005260:Female; D017353:Gene Deletion; D015684:Gene Products, pol / Q000096:biosynthesis / Q000235:genetics*; D056945:Hep G2 Cells; D006515:Hepatitis B virus / Q000201:enzymology / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000821:virology; D006801:Humans; D008103:Liver Cirrhosis / Q000821:virology; D008113:Liver Neoplasms / Q000473:pathology* / Q000821:virology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D035683:MicroRNAs / Q000037:antagonists & inhibitors* / Q000235:genetics; D008875:Middle Aged; D009368:Neoplasm Transplantation; D011379:Prognosis; D011485:Protein Binding / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D014183:Transplantation, Heterologous; D000097869:Polo-Like Kinase 1
chemical_list: D018797:Cell Cycle Proteins; D004279:DNA, Viral; D015684:Gene Products, pol; D035683:MicroRNAs; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D000097869:Polo-Like Kinase 1; C544266:MIRN100 microRNA, human; C066027:P protein, Hepatitis B virus
keywords: hepatitis B; hepatocellular carcinoma; microRNA-100; molecular oncology; mutation screening
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