Hepatitis B virus X mutants, present in hepatocellular carcinoma tissue abrogate both the antiproliferative and transactivation effects of HBx.
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Hepatitis B virus X mutants, present in hepatocellular carcinoma tissue abrogate both the antiproliferative and transactivation effects of HBx. / Sirma, Hüseyin; Giannini, C; Poussin, K; Paterlini, P; Kremsdorf, D; Bréchot, C.
In: ONCOGENE, Vol. 18, No. 34, 34, 1999, p. 4848-4859.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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T1 - Hepatitis B virus X mutants, present in hepatocellular carcinoma tissue abrogate both the antiproliferative and transactivation effects of HBx.
AU - Sirma, Hüseyin
AU - Giannini, C
AU - Poussin, K
AU - Paterlini, P
AU - Kremsdorf, D
AU - Bréchot, C
PY - 1999
Y1 - 1999
N2 - Chronic infection by HBV is the leading cause of hepatocellular carcinoma in man. Several lines of evidence suggest that the viral transactivator HBx plays a critical role in the molecular pathogenesis of HBV-related HCC. To study the actual impact of HBx and the mechanism of its action, we have recently cloned and characterized a set of X-sequences from HCC in patients with chronic infection by HBV. In the present study, we have compared the effects of HBx and its naturally arising mutants on cell growth and viability. We report that HBx inhibits clonal outgrowth of cells and induces apoptosis by a p53-independent pathway. Furthermore, HBx expression induced a late G1 cell cycle block prior to their counterselection by apoptosis. Importantly, mutations in the HBx-gene evolving in hepatocellular carcinoma abolished both HBx-induced growth arrest and apoptosis. Using a panel of engineered mutants we have mapped the growth suppressive effect of HBx to domains shown to be required for its transactivating function. Based on these results, we propose that abrogation of the anti-proliferative and apoptotic effects of HBx by naturally occurring mutations might render the hepatocytes susceptible to uncontrolled growth and contribute to multistep hepatocarcinogenesis associated with HBV-infection.
AB - Chronic infection by HBV is the leading cause of hepatocellular carcinoma in man. Several lines of evidence suggest that the viral transactivator HBx plays a critical role in the molecular pathogenesis of HBV-related HCC. To study the actual impact of HBx and the mechanism of its action, we have recently cloned and characterized a set of X-sequences from HCC in patients with chronic infection by HBV. In the present study, we have compared the effects of HBx and its naturally arising mutants on cell growth and viability. We report that HBx inhibits clonal outgrowth of cells and induces apoptosis by a p53-independent pathway. Furthermore, HBx expression induced a late G1 cell cycle block prior to their counterselection by apoptosis. Importantly, mutations in the HBx-gene evolving in hepatocellular carcinoma abolished both HBx-induced growth arrest and apoptosis. Using a panel of engineered mutants we have mapped the growth suppressive effect of HBx to domains shown to be required for its transactivating function. Based on these results, we propose that abrogation of the anti-proliferative and apoptotic effects of HBx by naturally occurring mutations might render the hepatocytes susceptible to uncontrolled growth and contribute to multistep hepatocarcinogenesis associated with HBV-infection.
M3 - SCORING: Zeitschriftenaufsatz
VL - 18
SP - 4848
EP - 4859
JO - ONCOGENE
JF - ONCOGENE
SN - 0950-9232
IS - 34
M1 - 34
ER -
