[Hepatitis B virus X protein suppressing adriamycin-induced apoptosis of HepG2 cells].

OBJECTIVES: To investigate the effect of hepatitis B virus X protein (HBx) on adriamycin-induced apoptosis of hepatocellular carcinoma cells. METHODS: HBx 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. RESULTS: Under 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. CONCLUSION: A HepG2 cell line expressing GFP and GFP-HBx fusion proteins was successfully established. HBV X protein blocks adriamycin-induced apoptosis of these HepG2 cells.

Effects of c-myb antisense RNA on TGF-beta1 and beta1-I collagen expression in cultured hepatic stellate cells.

AIM: To investigate the effects of c-myb antisense RNA on cell proliferation and the expression of c-myb, TGF-beta1 and beta1-I collagen in cultured hepatic stellate cells (HSC) from rats. METHODS: Recombinant retroviral vector of c-myb antisense gene (pDOR-myb) was constructed, and then transfected into retroviral package cell line PA317 by means of DOTAP. The pseudoviruses produced from the resistant PA317 cells were selected with G418 to infect HSCs isolated from rat livers. The cell proliferation was measured by 3-[4, 5-Dimethylthiazolzyl]-2, 5-diphenyl tetrazo-dium bromide(MTT) method. The expression of c-myb, alpha (1)-I collagen and TGF-beta1 mRNA, and c-myb protein in HSCs was detected with semi-quantitive reverse transeription-polymerase chain reaction (RT-PCR) and Western-blot respectively. RESULTS: HSCs from rats were isolated successfully with the viability >98%. In the pDOR-myb infected HSCs, the c-myb protein expression, cell proliferation,and alpha (1)-I collagen and TGF-beta1 mRNA expression were repressed significantly compared with their corresponding control groups (P<0.01). CONCLUSION: c-myb plays a key role in activation and proliferation of HSC. c-myb antisense RNA can inhibit cell proliferation, alpha (1)-I collagen and TGF-beta1 mRNA expression, suggesting that inhibition of c-myb gene expression might be a potential way for the treatment of liver fibrosis.

Prevalence of hepatitis G virus infection and homology of different viral strains in Southern China.

AIM: To investigate the prevalence of hepatitis G virus (HGV) infection and to analyse the homology of different HGV strains in Southern China. METHODS: A total of 1993 sera from different groups in Guangdong, Hong Kong, and Yunnan were detected by reverse transcription polymerase chain reaction (RT-PCR). The nucleotide sequences of 5'untranslated region (5'UTR) derived from 20 strains and NS5 region from 3 strains were determined. RESULTS: The positive rate of HGV RNA was 0.89 % in community population, 2.57 % in blood donors, 17.86 % in intravenous drug abusers, 14.13 % in patients with hemodialysis, 13.66 % in those with hepatocellular carcinoma, 25.30 % in non A-E hepatitis, 7.22 % in hepatitis B, 12.73 % in hepatitis C, 41.67 % in patients received bone marrow transplantation, respectively. The homology was 90.40-100 % in 5'UTR among different strains, while that of NS5 region was 93.3-94 % in nucleotide sequence, and 97-99.2 % in amino acid sequence. CONCLUSION: These results showed that there was a high incidence of HGV infection in patients from Southern China, being treated for bone marrow transplantation, hepatocellular carcinoma and those on haemodialysis. Furthermore, there was also a high frequency of co-infection of HGV with HBV, HCV, non A-E viral hepatitis and that among intravenous drug abusers. The study also showed that sequence variation in different strains was associated with geographical factors but there was no significant difference in 5'UTR in circulating viruses between different patient groups. Finally, by sequential analysis of viral species present in individual patients over a three months period there was no evidence of sequence variation in the 5' UTR.

The levels of serum fibrosis marks and morphometric quantitative measurement of hepatic fibrosis.

OBJECTIVE: To study the relationship between the serum levels of hyaluronic acid (HA), procollagen type III (PCIII), collagen type IV (CIV) and the histological degree of hepatic fibrosis evaluated by image analysis, and the clinical significance of serum HA, PCIII, CIV in the diagnosis of hepatic fibrosis in patients with chronic viral hepatitis. METHODS: The concentrations of serum HA, PCIII, CIV in 151 patients with chronic viral hepatitis were measured by radioimmunoassay. Liver biopsies were performed in all the patients. Histological sections of 4 microm thickness were stained with Masson's trichrome for fibrosis assessment. Morphometric quantitative measurements for hepatic fibrosis assessment in the 4 microm sections were performed using a fully automated image analysis system. Serum levels of HA, PCIII, and CIV were analyzed at different stages of liver pathology and compared with the morphometric quantitative measurements of hepatic fibrosis. RESULTS: The serum levels of HA, PCIII, CIV all elevated gradually with the progression of the disease, and all reached the highest in patients with liver cirrhosis. There was a significant difference in the levels of these 3 components between liver cirrhosis group and the other groups (P<0.05). They all increased steadily with the histological stages of hepatic fibrosis, and reached the highest levels in stage IV. The serum levels of HA, PCIII, CIV were all positively correlated with the histological stages of liver sections and the morphometric measurement (P<0.001). The coefficients with stages were 0.694, 0.493, 0.552 (P<0.001), respectively and with surface density of total collagen on liver biopsy sections by image analysis were 0.715, 0.595, 0.573 (P<0.001), respectively. CONCLUSION: The serum levels of HA, PCIII, CIV were in consistent with the degree of hepatic fibrosis, and the determination of these marks is valuable for detecting hepatic fibrosis.

Codon 249 mutations of p53 gene in non-neoplastic liver tissues.

AIM:To study the significance of p53 gene in hepatocarcinogenesis through analyzing codon 249 mutations of p53 gene in non-neoplastic liver tissues.METHODS:Codon 249 mutation was detected using single-stranded conformational polymorphism analysis and allele-specific PCR in liver tissues from 10 cases of chronic hepatitis, 5 cases of cirrhosis and 20 cases of HCCs.RESULTS:The detection rate of codon 249 mutation in chronic hepatitis, cirrhosis and pericancerous tissues was 70% (7/10), 100% (5/5) and 70% (14/20), respectively by AS-PCR. These mutations could not be detected by SSCP analysis. The detection rates were 65% (13/20) and 45% (9/20) in cancerous tissues by AS-PCR and SSCP analysis.CONCLUSION:Codon 249 mutations of p53 gene were very popular in non-neoplastic liver tissues though the number of those mutant cells was only in subsection. Those mutations in cancerous tissues might take place in the stage before the formation of tumor.