Xiaojun Li1, Jiangbo Zhang1, Ziwei Yang1, Jingting Kang1, Suzhen Jiang2, Ting Zhang1, Tingting Chen1, Meng Li1, Quanjun Lv3, Xiangmei Chen4, Malcolm A McCrae5, Hui Zhuang1, Fengmin Lu6. 1. Department of Microbiology & Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, PR China. 2. Department of Gastroenterology & Hepatology, Chinese PLA General Hospital, Beijing, PR China. 3. Department of Nutrition and Food Hygiene, College of Public Health, Zhengzhou University, Henan, PR China. 4. Department of Microbiology & Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, PR China. Electronic address: xm_chen6176@bjmu.edu.cn. 5. The Pirbright Institute, Pirbright, UK. 6. Department of Microbiology & Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, PR China. Electronic address: lu.fengmin@hsc.pku.edu.cn.
Abstract
BACKGROUND & AIMS: Although hepatitis B virus (HBV) integration into the human genome has been considered as one of the major causative factors to hepatocarcinogenesis, the underlying mechanism(s) was still elusive. Here we investigate the essential difference(s) of HBV integration between HCC tumor and adjacent non-tumor tissues and explore the factor(s) that determine the oncogenicity of HBV integration. METHODS: 1115 HBV integration sites were collected from four recent studies. Functional annotation analysis of integration targeted host genes (ITGs) was performed using DAVID based on Gene Ontology and KEGG pathway databases. Array-based expression profiles, real-time qPCR and western blot were used to detect the expression of recurrent integration targeted genes (RTGs). The biological consequences of the overexpression of UBXN8 in 8 HCC cell lines were studied in vitro. RESULTS: HBV is prone to integrate in genic regions (exons, introns, and promoters) and gene-dense regions. Functional annotation analysis reveals that, compared to those in adjacent non-tumor tissues, ITGs in HCC tumor tissues were significantly enriched in functional terms related to negative regulation of cell death, transcription regulation, development and differentiation, and cancer related pathways. 32% of the 75 RTGs identified in this analysis expressed abnormally in HCC tissues. UBXN8, one of the RTGs, was identified as a new tumor suppressor candidate which functions in a TP53 dependent manner. CONCLUSIONS: The oncogenicity of HBV integration was determined, to some extend by the function of HBV integration targeted host genes in HCC.
BACKGROUND & AIMS: Although hepatitis B virus (HBV) integration into the human genome has been considered as one of the major causative factors to hepatocarcinogenesis, the underlying mechanism(s) was still elusive. Here we investigate the essential difference(s) of HBV integration between HCC tumor and adjacent non-tumor tissues and explore the factor(s) that determine the oncogenicity of HBV integration. METHODS: 1115 HBV integration sites were collected from four recent studies. Functional annotation analysis of integration targeted host genes (ITGs) was performed using DAVID based on Gene Ontology and KEGG pathway databases. Array-based expression profiles, real-time qPCR and western blot were used to detect the expression of recurrent integration targeted genes (RTGs). The biological consequences of the overexpression of UBXN8 in 8 HCC cell lines were studied in vitro. RESULTS:HBV is prone to integrate in genic regions (exons, introns, and promoters) and gene-dense regions. Functional annotation analysis reveals that, compared to those in adjacent non-tumor tissues, ITGs in HCC tumor tissues were significantly enriched in functional terms related to negative regulation of cell death, transcription regulation, development and differentiation, and cancer related pathways. 32% of the 75 RTGs identified in this analysis expressed abnormally in HCC tissues. UBXN8, one of the RTGs, was identified as a new tumor suppressor candidate which functions in a TP53 dependent manner. CONCLUSIONS: The oncogenicity of HBV integration was determined, to some extend by the function of HBV integration targeted host genes in HCC.