CREB/ATF proteins, the effectors of the mitogenic ras-raf-MAPK, JNK and p38MAPK pathways, mediate gene expression required for proliferation, response to stress, differentiation and apoptosis. CREB/ATF proteins, via the bZip domain, interact with Hepatitis B virus (HBV) X protein (pX), implicated in hepatocellular carcinoma (HCC) development. Since viral on co-proteins effect transformation by deregulating key, cellular growth control mechanisms, we hypothesize that pX interaction with CREB/ATF is important in hepatocyte transformation. In the previous funding period we have tested specific aspects of this hypothesis and have: 1) delineated the minimal region of pX required for interaction with CREB/ATF proteins; and 2) developed and characterized a novel, comparative in vitro cellular model of pX-mediated hepatocarcinogenesis. This cellular model is comprised of two tetracycline-regulated, pX-expressing cell lines derived from the AML12immortalized hepatocyte cell line. The 3pX-1 cell line is a differentiated hepatocyte that becomes transformed by pX; the other, 4pX-1, is a de-differentiated hepatocyte cell line that does not display pX-mediated transformation, but is sensitive to pX-mediated apoptosis. The goal of this proposal is to gain better understanding of the mechanism of pX-mediated hepatocyte transformation, and the role of CREB/ATF proteins in pX-mediated hepatocyte transformation and apoptosis. Since our earliest studies defined the minimal pX region required for increased CREB/ATF transcriptional efficacy, in Aim 1 we will delineate the minimal pX region required for transformation in differentiated hepatocytes vs. apoptosis in de-differentiated hepatocytes.
In Aim 2 we will investigate the mechanism by which pX sensitizes de-differentiated 4pX-1 cells to apoptosis, and the pX-mediated mechanism(s) that rescue 4pX-1 cells from apoptosis, resulting in transformed hepatocytes. Thus, we will investigate the hypothesis that the de-differentiated 4pX-1 cells model a precancerous precursor for HCC.
In Aim 3 we will characterize two cloned, novel ESTs expressed during pX-mediated hepatocyte transformation. The proposed studies will elucidate further the mechanism of pox-mediated transformation; the mechanism of pX mediated apoptosis, and the cellular precancerous precursor of HCC; and will characterize new molecules, which have the potential of being early diagnostic markers in human HCC development. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
2R01DK044533-10
Application #
6615971
Study Section
Special Emphasis Panel (ZRG1-SSS-T (01))
Program Officer
Sato, Sheryl M
Project Start
1993-05-01
Project End
2007-04-30
Budget Start
2003-05-01
Budget End
2004-04-30
Support Year
10
Fiscal Year
2003
Total Cost
$319,255
Indirect Cost
Name
Purdue University
Department
Other Basic Sciences
Type
Schools of Veterinary Medicine
DUNS #
072051394
City
West Lafayette
State
IN
Country
United States
Zip Code
47907
Diab, Ahmed; Foca, Adrien; Zoulim, Fabien et al. (2018) The diverse functions of the hepatitis B core/capsid protein (HBc) in the viral life cycle: Implications for the development of HBc-targeting antivirals. Antiviral Res 149:211-220
Mani, Saravana Kumar Kailasam; Andrisani, Ourania (2018) Hepatitis B Virus-Associated Hepatocellular Carcinoma and Hepatic Cancer Stem Cells. Genes (Basel) 9:
Mani, Saravana Kumar Kailasam; Andrisani, Ourania (2018) Interferon signaling during Hepatitis B Virus (HBV) infection and HBV-associated hepatocellular carcinoma. Cytokine :
Zhang, Hao; Zhang, Yanqiu; Zhu, Xiaoyun et al. (2018) DEAD Box Protein 5 Inhibits Liver Tumorigenesis by Stimulating Autophagy via Interaction with p62/SQSTM1. Hepatology :
Diab, Ahmed; Foca, Adrien; Fusil, Floriane et al. (2017) Polo-like-kinase 1 is a proviral host factor for hepatitis B virus replication. Hepatology 66:1750-1765
Fan, H; Cui, Z; Zhang, H et al. (2017) DNA demethylation induces SALL4 gene re-expression in subgroups of hepatocellular carcinoma associated with Hepatitis B or C virus infection. Oncogene 36:2435-2445
Mani, Saravana Kumar Kailasam; Zhang, Hao; Diab, Ahmed et al. (2016) EpCAM-regulated intramembrane proteolysis induces a cancer stem cell-like gene signature in hepatitis B virus-infected hepatocytes. J Hepatol 65:888-898
Fan, H; Zhang, H; Pascuzzi, P E et al. (2016) Hepatitis B virus X protein induces EpCAM expression via active DNA demethylation directed by RelA in complex with EZH2 and TET2. Oncogene 35:715-26
Zhang, Hao; Xing, Zheng; Mani, Saravana Kumar Kailasam et al. (2016) RNA helicase DEAD box protein 5 regulates Polycomb repressive complex 2/Hox transcript antisense intergenic RNA function in hepatitis B virus infection and hepatocarcinogenesis. Hepatology 64:1033-48
Zhang, Hao; Diab, Ahmed; Fan, Huitao et al. (2015) PLK1 and HOTAIR Accelerate Proteasomal Degradation of SUZ12 and ZNF198 during Hepatitis B Virus-Induced Liver Carcinogenesis. Cancer Res 75:2363-74

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