OBJECTIVESTo investigate the effect of hepatitis B virus X protein (HBx) on adriamycin-induced apoptosis of hepatocellular carcinoma cells.

METHODSHBx gene fragment was amplified from subtype adr HBV plasmid by PCR, and inserted into Hind III and Kpn I sites of green fluorescent protein (GFP) eukaryotic expression vector pEGFP-C1 to construct recombinant pGFP/HBx. The pEGFP-C1 and pGFP-HBx were introduced into HepG2 cells by Lipofectamine 2000 to obtain HepG2 cells expressing GFP. GFP-HBx fusion protein was selected using G418. The expression of HBx gene was demonstrated by RT-PCR analysis. HepG2, HepG2/GFP and HepG2/GFP-HBx cells were treated with adriamycin (2.5 microg/ml), and apoptosis of the cells was determined by their morphological changes, trypan blue exclusion, and flow cytometry analysis.

RESULTSUnder a fluorescence microscope, visible expression of GFP and GFP-HBx fusion proteins were observed in HepG2/GFP and HepG2/GFP-HBx cells, even after growing over 70 generations. RT-PCR analysis showed that HBx gene was expressed in HepG2/GFP-HBx cells. Trypan blue exclusion showed adriamycin induced time-dependent cell death in HepG2 and HepG2/GFP cells while no significant cell death was observed in HepG2/GFP-HBx cells. Flow cytometry analysis showed that apoptosis rates in HepG2/GFP-HBx (3.94%) cells were significantly lower than those in HepG2 (59.03%) and HepG2/GFP cells (61.38%) at 36 hours after the adriamycin treatment (P < 0.01). No significant differences of apoptosis rates of HepG2/GFP-HBx (3.94%) and of the untreated cells (2.12%, 2.78%, 2.55%) (P > 0.05) were observed.

CONCLUSIONA HepG2 cell line expressing GFP and GFP-HBx fusion proteins was successfully established. HBV X protein blocks adriamycin-induced apoptosis of these HepG2 cells.

Apoptosis ; drug effects ; Doxorubicin ; pharmacology ; Hep G2 Cells ; Humans ; Plasmids ; Trans-Activators ; genetics

The objective of study was to investigate the relationship between expressions of CIITA and MHC molecules in five human cell lines. The expressions of MHC molecules and CIITA protein were detected by Western blot, immunohistochemistry and flow cytometry. The expression of CIITA gene was measured by RT-PCR. The results indicated that the expression of MHC-II molecules in 5 human cell lines was consistent with expression of CIITA. The cell lines constitutively expressed CIITA also expressed MHC-II molecules, the expression of MHC-II molecules in cell lines expressed CIITA after induction with IFN-gamma also recovered; the cell lines unexpressed CIITA after induction with IFN-gamma did not respond to IFN-gamma-promoting expression of MHC-II molecules. It is concluded that some cell lines cannot express MHC-II molecules which may be related with deficiency of CIITA expression. It suggest that CIITA participates in regulation of MHC-II molecule expression, which may plays a certain role in escape from carcinogenesis under surveillance of immune system.
Cell Line ; Genes, MHC Class II ; Humans ; Interferon-gamma ; pharmacology ; Nuclear Proteins ; metabolism ; Trans-Activators ; metabolism ; Tumor Cells, Cultured

Apoptosis ; drug effects ; Carcinoma, Hepatocellular ; pathology ; Cell Line, Tumor ; Doxorubicin ; pharmacology ; Hepatocytes ; cytology ; drug effects ; Humans ; Trans-Activators ; genetics

In order to study the roles of HBx and calcium inhibitor verapamil in apoptosis of human normal hepatic cells, L02-off, a pTet-off stably integrated human hepatic cell line was established, in which HBx expression was tightly induced by Doxycycline. The effect of different amounts of HBx and verapamil on apoptosis of human normal hepatic cells was detected. The study showed that apoptosis was triggered by accumulation of intracellular HBx, while verapamil had no effects on the apoptotic process. It was concluded that apoptosis mediated by HBx was dose-dependent but calcium-independent.
Apoptosis ; drug effects ; Calcium ; pharmacology ; Calcium Channel Blockers ; pharmacology ; Cells, Cultured ; Dose-Response Relationship, Drug ; Hepatitis B Antigens ; pharmacology ; Hepatocytes ; cytology ; Humans ; Trans-Activators ; pharmacology ; Verapamil ; pharmacology

In order to study the roles of HBx and calcium inhibitor verapamil in apoptosis of human normal hepatic cells, L02-off, a pTet-off stably integrated human hepatic cell line was established, in which HBx expression was tightly induced by Doxycycline. The effect of different amounts of HBx and verapamil on apoptosis of human normal hepatic cells was detected. The study showed that apoptosis was triggered by accumulation of intracellular HBx, while verapamil had no effects on the apoptotic process. It was concluded that apoptosis mediated by HBx was dose-dependent but calcium-independent.
Apoptosis/*drug effects ; Calcium/pharmacology ; Calcium Channel Blockers/pharmacology ; Cells, Cultured ; Dose-Response Relationship, Drug ; Hepatitis B Antigens/pharmacology ; Hepatocytes/*cytology ; Trans-Activators/*pharmacology ; Verapamil/*pharmacology

Carcinoma, Hepatocellular ; pathology ; virology ; Cisplatin ; pharmacology ; Drug Synergism ; Flavonoids ; pharmacology ; Humans ; Liver Neoplasms ; pathology ; virology ; Trans-Activators ; Tumor Cells, Cultured ; Viral Regulatory and Accessory Proteins ; drug effects

OBJECTIVETo delineate the effects of HBV X gene and of As(2)O(3) on p53 expression and activity in HepG2 cells by shRNA-mediated RNA interference (RNAi).

METHODSHepG2 cells and cells with stable expression of HBV X gene, HepG2-X, were treated with 2 micromol/L As(2)O(3), and the corresponding untreated cells were used as controls. Cell and nuclear lysates were extracted. Total level and the relative activity absorbance of p53 were detected by modified ELISA. HBV X gene sequence-specific shRNA expression vectors, Xi-S1 and Xi-S2, and sequence-unrelated control Xi-S3 were transfected into HepG2-X. The effect of As(2)O(3) on p53 expression and activity were retested.

RESULTSTotal p53 level was up-regulated and its relative activity ratio was enhanced by As(2)O(3) in HepG2 and HepG2-X cells. The total p53 level induced by As(2)O(3) was further up-regulated by HBX expression, while its relative activity was significantly suppressed. The suppression was removed after HBX expression was suppressed by shRNA.

CONCLUSIONAs(2)O(3) could up-regulate p53 expression and enhance its activity. shRNA-mediated RNA interference is conveniently being used in studies on the effect of HBV X gene expression on p53 expression and activity. HBV X expression could up-regulate p53 gene expression level induced by As(2)O(3), while it suppressed the activity of p53.

Apoptosis ; Arsenicals ; pharmacology ; Gene Expression ; Hep G2 Cells ; Hepatitis B virus ; genetics ; Humans ; Oxides ; pharmacology ; RNA, Small Interfering ; Trans-Activators ; genetics ; Tumor Suppressor Protein p53 ; genetics ; metabolism

BACKGROUNDHepatitis B virus (HBV) X protein (HBx) and p53 could mutually down-regulate at transcriptional level and HBx could bind with p53 protein within its transactivation domain and inhibit the function of p53 protein. In recent years, effects of arsenic trioxide (As2O3) on the expression of p53 protein have been widely studied, while little is known about the activity of p53 protein. This study was undertaken to delineate the effect of HBV X gene and As2O3 on p53 protein expression (level and activity) in HepG2 cells by small hairpin RNA (shRNA)-mediated RNA interference (RNAi) technique.

METHODSCell line HepG2 and cells with stable expression of HBV X gene (HepG2-X) were treated with 2 micromol/L As2O3, with corresponding untreated cells serving as controls. Cell lysates and nuclear extracts were extracted. Total level and the relative activity of p53 protein were detected by modified enzyme-linked immunosorbent assay (ELISA). HBV X gene sequence-specific shRNA expression vector (pXi-1 and pXi-2) and sequence-unrelated control (pXi-3) were transfected into HepG2-X. Single cell clone with stable expression of shRNA was selected and exposed to propagating culture. The effect of As2O3 on p53 protein expression and activity was re-observed.

RESULTSTotal p53 protein level was up-regulated and its relative activity ratio was enhanced by As2O3 in HepG2 and HepG2-X cells. The total p53 protein level induced by As2O3 was up-regulated by HBV X gene expression, while its relative activity was significantly suppressed. The suppression was removed after HBV X gene expression was repressed by shRNA.

CONCLUSIONSAs2O3 up-regulates p53 protein expression and enhance its activity. HBV X up-regulates As2O3 induced-p53 protein expression while suppresses its activity.

Arsenicals ; pharmacology ; Cell Line, Tumor ; Enzyme-Linked Immunosorbent Assay ; Humans ; Oxides ; pharmacology ; RNA Interference ; Trans-Activators ; genetics ; Tumor Suppressor Protein p53 ; analysis

OBJECTIVEThis paper studied the effect of RNaseP against CIITA on repressing class II MHC (MHCII) expression.

METHODSIt was constructed that M1-RNA with guide sequences (GS), recognizing the 629 site of CIITA (M1-629-GS), by PCR from pTK117 plasmid, then was cloned into psNAV (psNAV-M1-629-GS). CIITA target gene was obtained from Raji cell by RT-PCR, and then inserted into pGEM-7zf (+) (pGEM-800). psNAV-M1-629-GS and pGEM-800 were transcribed and then mixed up and incubated in vitro. Stable transfectants of hepatocyte with psNAV-M1-629-GS by nanometer were tested for MHCII induction by recombinant human interferon-gamma (IFN-gamma). mRNA abundance of CIITA was measured by RT-PCR.

RESULTSIt showed that M1-629-GS could exclusively cleave pGEM-800 that formed a base pair with the GS. When induced with IFN-gamma, the expression of HLA-DR, -DP, -DQ on psNAV-M1-629-GS+ hepatocyte was (1.01+/-0.51)%, (4.37+/-1.28)%, (1.98+/-0.42)% respectively, was down-modulated 90.65%, 89.11% and 65.32% compared with control, while the mRNA content of CIITA reduced significantly (P<0.01).

CONCLUSIONM1-629-GS could effectively repress MHCII expressing through cleaving CIITA mRNA. These results provided insight into the future application of it as a new nucleic acid drug against the rejection of hepatic transplantation.

Graft Rejection ; prevention & control ; Histocompatibility Antigens Class II ; analysis ; Humans ; Liver Transplantation ; immunology ; Nuclear Proteins ; genetics ; RNA, Messenger ; analysis ; Ribonuclease P ; pharmacology ; Trans-Activators ; genetics

Apoptosis ; drug effects ; Hepatocytes ; pathology ; virology ; Humans ; Liver Neoplasms ; pathology ; virology ; Mutation ; Plasmids ; genetics ; Trans-Activators ; genetics ; pharmacology ; Transfection ; Tumor Cells, Cultured