Abstract LB-71: Carcinogenic significance of integrated hepatitis b viral factors and its genotype in hepatocarcinogenesis.

Abstract

Abstract Integration of Hepatitis B Virus (HBV) is one of the major causes underlying Hepatocellular carcinoma (HCC) development. Recent studies revealed that altered expression of multiple cellular genes due to multiple random integration of viral factors lead to development of HCC. The present study aims to identify the carcinogenic significance of integrated HBV genome and its genotype in HCC development. Host-Viral Junctions were determined in HCC (T) /adjacent tissues (NT) and cirrhotic (-HCC) tissues by sequencing of Alu PCR product followed by sequence blast. Host gene expression was checked by real time PCR. Competition between two coexisting genotypes was studied by replication assay using genotype specific PCR from media and viral core particle isolated from genotype specific plasmid transfected HepG2 cell line. Similarly, each viral genotype mediated DNA damage (γH2aX foci by confocal microscopy), ROS generation (DCFDA quantitation by Facs analysis and ER stress marker GRP78 luciferase assay), homologous recombination efficiency were also compared. HBV integration was observed in 66.7% of T (8/12), 33.3% (4/12) NT and 75% (6/8) cirrhotic tissue samples in 18, 4 and 8 different locations respectively. These viral integration analysis within or close to several host genes, such as genes involved in differentiation, signaling, stress response, cell cycle, telomere regulations (8/30, 26.7%) etc and most of them showed altered expression. Interestingly, C-terminal truncated HBX which lost its growth suppressive domain were observed more in T (5/8, 62.5%) than NT (2/4, 50%) tissue samples. Most importantly, upon genotype analysis of each five clones in serum and tissue showed genotype C preferentially integrated in coexistence of both C and D genotype as “free virus” in tissue but D genotype observed in circulation. Genotype specific PCR from HBV/C & D cotransfected media showed that in presence of HBV/C, D replicates better than C but HBV/C with high recombination frequency generates more DNA damage and facilitate viral integration. Thus random integration of HBV in host chromosome causes alterations in oncogenic gene expression and these alterations presumably lead to clonal selection of hepatocyte that acquires a growth advantage and proceeds towards HCC. Genotype of HBV is an important determining factor for HBV integration and liver inury. Citation Format: Soma Banerjee, Somenath Datta, Shrabasti Roychoudhury, Debanjali Dasgupta, Amit Ghosh, Gaurav Roy, Simanti Datta, Abhijit Chowdhury. Carcinogenic significance of integrated hepatitis b viral factors and its genotype in hepatocarcinogenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-71. doi:10.1158/1538-7445.AM2013-LB-71