ABSTRACT
To study the effect of micro (mi)RNA on cellular proliferation induced by hepatitis B x protein, HBx, in human liver cells and to investigate the underlying molecular mechanism of this cancer-related effect. The human L02 hepatocyte cell line was stably transfected with HBx (L02/HBx) or an HBx mutant (L02/HBx-d382) that induces higher levels of cellular proliferation. The differential miRNA expression profiles were determined by microarray analysis and confirmed by real-time PCR. Two miRNAs, miR-338-3p and miR-551b, that were found to be significantly down-regulated in the L02/HBx-d382 cells were selected for further study and transfected individually into cells using the lipofectamine procedure. The cell survival rate was analyzed by MTT assay, and cell cycles were assessed by flow cytometry. Expressions of cyclinD1, cyclinG1, and E2F1 were assessed by real-time PCR and Western blotting. Compared with the microarray miRNA profile of L02/pcDNA3.0 cells, six miRNAs were up-regulated and five miRNAs were down-regulated in the L02/HBx-d382 cells, while four miRNAs were up-regulated and 12 were down-regulated in the L02/HBx cells. The microarray results were consistent with real-time PCR results. Transfection of miR-338-3p and miR-551b significantly inhibited the cell survival rates (P less than 0.001) and induced G0/G1 phase cycle arrest. According to MTT results: for L02/HBx-d382 cells, compared with lipofectamine or non-transfected (NC) controls, the t value of miR-338-3p was 10.402, 9.133 and the t value of miR-551b was 8.763, 7.403; for L02/HBx cells, compared with lipofectamine or NC controls, the t value of miR-338-3p was 9.105, 8.074 and the t value of miR-551b was 7.673, 7.52. According to flow cytometry results: for L02/HBx-d382 cells, compared with lipofectamine or NC controls, the t value of miR-338-3p was 12.173, 11.107 and the t value of miR-551b was 15.364, 13.377; for L02/HBx cells, compared with lipofectamine or NC controls, the t value of miR-338-3p was 15.416, 13.378, and the t value of miR-551b was 13.276, 13.109. The protein levels of cyclinD1, cyclinG1, and E2F1 were significantly reduced by both miR-338-3p and miR-551b ( P less than 0.001). For L02/HBx-d382 cells, compared with lipofectamine or NC controls: E2F1 had t = 11.132, 10.031 and 12.017, 10.973, respectively; cyclinD1 had t = 15.654, 15.013 and 15.447, 14.733, respectively; cyclinG1 had t = 8.017, 7.661 and 7.402, 7.417, respectively. For L02/HBx cells, compared with lipofectamine or NC controls: E2F1 had t = 14.244, 13.331 and 15.022, 14.468, respectively; cyclinD1 had t = 8.695, 8.137 and 7.877, 7.503, respectively; cyclinG1 had t = 7.73, 7.471 and 7.596, 7.41, respectively. In contrast, the mRNA levels for E2F1, cyclinD1, and cylcinG1 showed no significant differences between the miRNA transfected cells and controls. Wild-type HBx and the high proliferation-inducing mutant HBx can influence the miRNA expression profile of L02 cells. HBx down-regulates miR-338-3p and miR-551b in L02 cells, and the high proliferation-inducing mutant has a more robust effect. The mechanism of miR-338-3p- or miR-551b-mediated cell growth inhibition appears to be related to the direct modulation of cyclinD1, cyclinG1, and E2F1.
Subject(s)
Humans , Blotting, Western , Carcinoma, Hepatocellular , Genetics , Metabolism , Pathology , Cell Cycle , Cell Line , Cell Proliferation , Cyclins , Genetics , Metabolism , Gene Expression Regulation, Neoplastic , Genes, Viral , Hepatitis B virus , Genetics , Metabolism , Hepatocytes , Metabolism , Pathology , Liver Neoplasms , Genetics , Metabolism , Pathology , MicroRNAs , Genetics , Metabolism , Mutation , Oligonucleotide Array Sequence Analysis , RNA, Messenger , Genetics , Real-Time Polymerase Chain Reaction , Trans-Activators , Genetics , Metabolism , TransfectionABSTRACT
<p><b>OBJECTIVES</b>To study the relationship between quasispecies of hepatitis B virus and the clinical manifestations of their infection, and to find the answer of why different quasispecies of HBV with the same genotype can induce different clinical situations.</p><p><b>METHODS</b>Sixty serum samples, in all of which HBVs of genotype B exist, taken from 32 chronic asymptomatic carriers and 28 severe chronic hepatitis patients, were collected to detect quasispecies of HBV DNA by melt curve approach. Then the relationship between quasispecies of HBV of the same genotype and the clinical situation of their infection was studied by comparing the wave crests of the two sample groups.</p><p><b>RESULTS</b>The data of the 60 serum samples of HBV of genotype B detected by melt curve showed that HBV DNA in severe chronic hepatitis patients had more wave crests than that in chronic asymptomatic carriers (P < 0.05), suggesting that HBV in severe chronic hepatitis patients had more quasispecies than in the chronic asymptomatic carriers.</p><p><b>CONCLUSION</b>The numbers of quasispecies of HBV correlate with the clinical situations of their infection. In the patients infected by HBV of the same genotype, those who have more HBV quasispecies would have more severe clinical manifestations.</p>
Subject(s)
Adolescent , Adult , Child , Female , Humans , Male , Middle Aged , Genotype , Hepatitis B virus , Classification , Genetics , Hepatitis B, Chronic , VirologyABSTRACT
<p><b>OBJECTIVE</b>To establish a cell model of secreted alkaline phosphatase (SEAP) co-controlled by HCV 5'NCR and NS3 serine protease in an effort to develop new antiviral agents.</p><p><b>METHODS</b>The fragments of HCV 5'NCR and NS3/4A-SEAP were amplified by PCR. They were fused into pBluescript SK+ to generate 5'NCR-NS3/4A-SEAP chimeric plasmid. The resulting chimeric gene was subcloned into HindIII/Bsu36 I site of pSEAP2-Control (a SEAP eukaryotic expression plasmid), to generate pNCR-NS3/4A-SEAP, in which the SEAP was fused in-frame to the downstream of NS4A/4B cleavage site. The SEAP activity in the culture media of transiently transfected cells was monitored quantitatively. The regulatory effect of HCV 5'NCR and NS3 serine protease on SEAP expression was measured by treatment of transfected cells with antisense oligodeoxynucleotide (ASODN) against HCV 5'NCR and TPCK, a irreversible serine protease inhibitor.</p><p><b>RESULTS</b>The SEAP activity in the culture media reached 80801+/-4794 RLU, and was significantly inhibited by 5 micromol/L, 10 micromol/L of ASODN (t=4.315, p<0.01; t=6.985, p<0.001) and 100 micromol/L of TPCK (t=6.949, P<0.001).</p><p><b>CONCLUSION</b>A cell model of SEAP co-controlled by HCV 5'NCR and NS3 serine protease has been successfully established. This might promote the screening of anti-viral drugs</p>