This proposal studies how certain elements of the innate immune system regulate levels of hepatitis B viral (HBV) DNA in liver tissues through genetic and epigenetic modification of viral DNA and how these same elements of the innate immune system contribute to carcinogenesis. This proposal is directly relevant to expanding our understanding of how chronic HBV infection leads to hepatocellular carcinoma. Recent advances in the understanding of HBV infection have shown that the risk for developing HCC is directly proportional to the serum levels of HBV DNA and reducing serum levels of HBV DNA are a major therapeutic target in the treatment of HBV. The biological mechanisms by which the host controls intrahepatic HBV replication remain incompletely understood, but better understanding may lead to more effective treatments that will prevent the development of HCC. We hypothesize that intrahepatic HBV levels are partly regulated by portions of the innate immune system that lead to mutations in the HBV genome through activation of the APOBEC family of proteins and that host methyltransferases methylate the HBV genome, leading to decreased HBV gene expression. We further hypothesize that these mechanisms contribute to carcinogenesis by leading to increased methylation of tumor suppressor genes (corresponding to the methylator phenotype in hepatocellular carcinoma).
In Aim One, we will determine the frequency of APOBEC induced hypermutations of the HBV genome in livers with chronic HBV infection and test the hypothesis that the extent of hypermutations predictes levels of HBV DNA.
In Aim Two, we will determine the frequency of methylation and the quantitative levels of methylation of non-integrated HBV using qualitative and quantitative methylation specific PCR and test the hypothesis that methylation levels of HBV DNA is predicitive of the levels of intrahepatic HBV. We also test the hypothesis that human cells can directly methylate HBV DNA and investigate the methyltransferases responsible.
In Aim Three, we study HBV associated HCCs to explore the hypothesis that they will demonstrate increased levels of tumor suppressor gene methylation. These studies will significantly advance our understanding and potentially our ability to treat HCC. This proposal studies how certain elements of the innate immune system regulate levels of hepatitis B viral (HBV) DNA in liver tissues through genetic and epigenetic modification of viral DNA and how these same elements of the innate immune system contribute to carcinogenesis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK078686-04
Application #
8007383
Study Section
Gastrointestinal Cell and Molecular Biology Study Section (GCMB)
Program Officer
Doo, Edward
Project Start
2008-01-15
Project End
2012-11-30
Budget Start
2010-12-01
Budget End
2012-11-30
Support Year
4
Fiscal Year
2011
Total Cost
$341,564
Indirect Cost
Name
Johns Hopkins University
Department
Pediatrics
Type
Schools of Medicine
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Ross, Hillary M; Daniel, Hubert D J; Vivekanandan, Perumal et al. (2011) Fibrolamellar carcinomas are positive for CD68. Mod Pathol 24:390-5
Li, Meng; Zhao, Hong; Zhang, Xiaosong et al. (2011) Inactivating mutations of the chromatin remodeling gene ARID2 in hepatocellular carcinoma. Nat Genet 43:828-9
Vivekanandan, Perumal; Torbenson, Michael; Ramakrishna, Banumathi (2011) Hepatitis B virus-associated hepatocellular carcinoma from India: role of viral genotype and mutations in CTNNB1 (beta-catenin) and TP53 genes. J Gastrointest Cancer 42:20-5
Vivekanandan, Perumal; Daniel, Hubert Darius-J; Kannangai, Rajesh et al. (2010) Hepatitis B virus replication induces methylation of both host and viral DNA. J Virol 84:4321-9
Vivekanandan, Perumal; Daniel, Hubert; Yeh, Matthew M et al. (2010) Mitochondrial mutations in hepatocellular carcinomas and fibrolamellar carcinomas. Mod Pathol 23:790-8
Yeh, Matthew M; Daniel, Hubert Darius-J; Torbenson, Michael (2010) Hepatitis C-associated hepatocellular carcinomas in non-cirrhotic livers. Mod Pathol 23:276-83
Vivekanandan, Perumal; Micchelli, Shien T L; Torbenson, Michael (2009) Anterior gradient-2 is overexpressed by fibrolamellar carcinomas. Hum Pathol 40:293-9
Vivekanandan, Perumal; Thomas, David; Torbenson, Michael (2009) Methylation regulates hepatitis B viral protein expression. J Infect Dis 199:1286-91
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