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ObjectiveTo investigate whether cytotoxic T lymphocyte （CTL）－derived exosomes can downregulate HBx expression and inhibit hepatic stellate cell （HSC） activation. MethodsThe supernatants of HepG2， HepGA14， and CTL cells were collected to extract exosomes， which were referred to as NC－exo， HBV－exo， and CTL－exo， respectively）. Transmission electron microscopy was used to observe their morphology， and Western Blot was used to measure the expression of the markers of exosomes CD63 and TSG101. NC－exo， HBV－exo， and CTL－exo labeled by BODIPY dye were mixed with HBV－exo at different ratios and were then co－cultured with HSC LX－2 （HSC－LX2）. A fluorescence microscope was used to observe whether exosomes could enter LX－2 cells， and an fluorescence microscope was used to observe cell morphological changes； quantitative real－time PCR （qPCR） was used to measure the expression of the activated biomarkers such as transforming growth factor－β1 （TGF－β1）， ɑ－smooth muscle actin （ɑ－SMA）， and collagen type I （Collagen I） in LX－2 cells. CTL－exo was added to the HepGA14 culture system； then qPCR was used to measure the mRNA expression level of HBV DNA， cccDNA， and HBx in exosomes in HepGA14 cells， and Western Blot was used to measure the protein expression level of HBx in exosomes. The t-test was used for comparison of normally distributed continuous data between two groups； a one-way analysis of variance was used for comparison between multiple groups， and the least significant difference t-test was used for further comparison between two groups. ResultsThe exosomes were all microcysts with a double－layer membrane structure and were circular or elliptical in shape， with the expression of the signature proteins CD63 and TSG101， and the vesicles had a diameter of 50－100 nm. The fluorescence microscope showed that exosomes could enter LX－2 cells， and HSC were enlarged with extended cell processes. The results of qPCR showed that there were significant differences in the expression levels of TGF－β1， ɑ－SMA， and Collagen I genes between the NC－exo， HBV－exo， NC－exo+HBV－exo， and Con groups （F=444.678， 417.144， and 571.508， all P<0.05）. After the intervention of HepGA14 cells with CTL－exo， qPCR results showed that compared with the control group， there were significant reductions in the expression levels of HBV DNA and cccDNA in HepGA14 cells （all P<0.05）， the relative mRNA expression level of HBx in exosomes （P<0.05）， and the protein expression level of HBx （P<0.05）. CTL－exo and HBV－exo were mixed at different ratios （2∶1， 5∶1， 10∶1） and were then used for the intervention of LX－2 cells， and qPCR results showed that the expression levels of TGF－β1， ɑ－SMA， and Collagen I genes in LX－2 cells gradually decreased with the increase in the ratio of CTL－exo between groups （P<0.05）. ConclusionCTL－exo can downregulate the protein expression of HBx in HBV－exo to inhibit HSC activation， suggesting that CTL－exo has an anti－hepatitis B liver fibrosis effect.
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@#Abstract: Objective To construct HepG2, Huh7 cell lines stably express hepatitis B virus X (HBx) mutant (C1653T, T1753C), and explore their effect on the biological behavior of hepatocellular carcinoma cells. Methods The lentivirus plasmid of pLVX-HBxC1653T-IRES-tdTomato, pLVX-HBxT1753C-IRES-tdTomato were obtained by PCR site mutagenesis according to wild type ayr HBx. Double enzyme digestion and Sanger sequencing were performed for accuracy of plasmid. Blank HepG2 and Huh7 cells were used as the control group, HepG2, Huh7 cells were infected by pLVX-HBx-IRES-tdTomato, pLVX-HBxC1653T-IRES-tdTomato, and pLVX-HBxT1753C-IRES-tdTomato lentivirus solution, then monoclonal cell was selected by 0.6 μg/mL puromycin. Immunostaining and Western Blot were performed for the verification of stable strains. CCK8 assay was performed for the proliferation capacity of stable strains. Western Blot was performed for expression of EMT-related signal molecules in cells. The independent samples t-test was used for comparison between two groups. Results Double enzyme digestion and Sanger sequencing showed that that the size of the cut fragments of recombinant lentiviral plasmids was correct, and the point mutation location and base substitution were correct, suggesting that the plasmid of pLVX-HBx-IRES-tdTomato, pLVX-HBxC1653T-IRES-tdTomato, pLVX-HBxT1753C-IRES-tdTomato were constructed successfully. Immunostaining and Western blot showed that HBX were expressed in stable strains, while there was no HBX expression in the blank control group, indicating that the HepG2 and Huh7 cell lines stably expressing HBx, HBxC1653T, HBxT1753C were successfully constructed. CCK8 assay showed that the proliferation capacity of HBx and mutant were enhanced compared to the control group (P<0.01), HBx C1653T displayed further additive the effect compared to HBx (P<0.05). Moreover, HBxC1653T mutation also significantly upregulated N-cadherin expression and downregulated E-cadherin expression, thus promoting the occurrence of EMT. Conclusions HepG2 and Huh7 cell lines stably expressing HBx, HBxC1653T, HBxT1753C were successfully constructed, HBxC1653T mutation significantly enhanced the proliferation of HCC cells and epithelial to mesenchymal transition occurrence.
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Objective:To investigate the effects of the interaction between ubiquitin-specific peptidase 22 (USP22) and hepatitis B virus X protein (HBx) on the protein level and the biological function of HBx.Methods:The interactions between HBx and USP22 were analyzed by GST pull-down, co-immunoprecipitation assay and confocal laser scanning assay. USP22 recombinant plasmids or specific siRNA were transiently co-transfected with HBx plasmids. Western blot were used to detect the protein level of HBx. The half-life and degradation pathway of HBx in the transfected cells treated with cycloheximide (CHX) or proteasome inhibitor MG132 were detected. In vivo ubiquitination assay was used to detect the ubiquitination of HBx with USP22 overexpression. Moreover, dual-luciferase reporter assay and colony formation assay were used to analyze the effects of USP22 on the biological function of HBx. Results:USP22 could interact with HBx in vivo and in vitro. USP22 significantly increased the stability of HBx and inhibited the proteasome-mediated degradation of HBx protein by reducing the ubiquitination of HBx, thereby enhancing the biological function of HBx. Conclusions:USP22 inhibited HBx protein degradation through ubiquitin-dependent proteasome pathway, thus enhancing the stability and biological function of HBx.
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Objective:To investigate whether hepatitis B virus X protein (HBx) mediates the podocyte injury through reactive oxygen species (ROS) /nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) signaling pathway.Methods:HBx-overexpressing lentivirus was transfected into renal podocytes of mouse to mimic the pathogenesis of hepatitis B virus-associated glomerulonephritis. Podocytes were divided into the following five groups: blank control group (no special treatment), negative control group (transfected with control lentivirus), HBx overexpression group (transfected with HBx overexpression lentivirus), HBx overexpression+NLRP3 siRNA group (transfected with HBx overexpression lentivirus and NLRP3 siRNA), and HBx overexpression+ROS inhibitor group (transfected with HBx overexpression lentivirus and adding ROS inhibitor). The morphological changes of podocytes were observed with electron microscope. The generation of ROS was detected by dichlorodihydrofluorescein diacetate assay (DCFH-DA). Hoechst 33342 staining was used to observe the morphological and quantitative changes of podocyte nuclei. Enzyme-linked immunosorbent assay was used to detect caspase-1 activity, and the levels of lactate dehydrogenase, interleukin (IL)-1β and IL-18. Quantitative real-time polymerase chain reaction and Western blotting were used to detect the expression levels of mRNA and protein of pyroptosis-related protein, such as NLRP3, apoptosis-associated speck-like protein containing card (ASC), caspase-1, IL-1β and IL-18. TUNEL staining and flow cytometer were used to detect the number of pyroptosis cells. Immunofluorescence staining was used to detect the expression levels of desmin and nephrin.Results:After successful infection of podocytes with HBx-overexpressing lentivirus, pyroptosis-related morphological changes in the cells were observed under electron microscope. The level of ROS in the HBx overexpression group was significantly higher compared to the negative control group ( P<0.05). Hoechst 33342 staining revealed condensed nuclei in the HBx overexpression group. TUNEL staining and flow cytometer demonstrated that podocytes underwent increased pyroptosis in the HBx overexpression group. The mRNA and protein expression levels of pyroptosis-related proteins such as NLRP3, ASC, caspase-1, IL-1β and IL-18 were up-regulated upon HBx overexpression (all P<0.05). Caspase-1 enzyme activity, lactate dehydrogenase and desmin expression levels were enhanced after HBx overexpression (all P<0.05). However, NLRP3 knockdown or addition of ROS inhibitors attenuated the pyroptosis and increased expression levels of pyroptosis-related proteins caused by HBx overexpression (all P<0.05). Conclusion:ROS/NLRP3 pathway plays an important role in HBx-induced podocyte pyroptosis.
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The pathogenesis of hepatitis B virus （HBV）-associated hepatocellular carcinoma （HCC） is complicated with the crosstalk of multiple factors and the multi-step processes. The main mechanisms underlying the HBV-induced HCC include:①integration of HBV DNA into the host hepatocyte genome to alter gene function at the insertion site，resulting in host genome instability and expression of carcinogenic truncated proteins;②HBV gene mutations at S，C，and X coding regions in the genome;③HBV X gene-encoded HBx protein activates proto-oncogenes and inhibits tumor suppressor genes，leading to the HCC occurrence. In this article，the recent research progress on the molecular mechanism of HBV-induced HCC is comprehensively reviewed，so as to provide insights into the prevention，early prediction and postoperative adjuvant therapy of HCC.
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Humanos , Carcinoma Hepatocelular , Hepatitis B/complicaciones , Virus de la Hepatitis B/genética , Hepatocitos , Neoplasias HepáticasRESUMEN
Objective:To investigate the effects of hepatitis B virus X (HBx) on hepatocellular carcinoma (HCC) proliferation, invasion, and sorafenib resistance.Methods:HepG2 cell line infected with HBx ORF lentivirus was set as the HBx high expression group and infected with empty vector was set as the negative control group. The interference group was infected with the HBx siRNA virus based on the HBx high expression group to reduce HBx expression. Interference control group as interference group but with infected empty vector virus. Western blotting was used to measure the protein level of HBx. Cell proliferation, invasion ability, and sorafenib semi-inhibitory concentration (IC50) of HCC cells under different HBx expression levels were respectively detected by cell proliferation assay kit, Transwell invasion assay, and cell titer-glo kit.Results:Western blotting showed that the stable cell lines were successfully established. Cell proliferation of the HBx high expression group was better than that of the blank control and negative control groups, and the cell proliferation of the interference group was lower than that of the interference control and HBx high expression groups, and the differences were all statistically significant ( P<0.05). The number of cells crossing Matrigel gel was (46.2±4.1), (50.7±5.1) and (48.2±5.2) in the blank control group, negative control group, and interference group, respectively. The number of cells crossing Matrigel gel in the HBx high expression group (124.2±8.3) and the interference control group (117.2±7.5) were higher than the above three groups, respectively, and the differences were all statistically significant ( P<0.05). The IC50 of cells in the HBx high expression group and the interference control group were (5.36±0.31) μmol/L and (5.48±0.20) μmol/L, respectively, which were higher than those in the blank control group, the negative control group, and the interference group (4.75±0.22) μmol/L, (4.60±0.14) μmol/L and (3.98±0.03) μmol/L. The differences were all statistically significant ( P<0.05). Conclusion:HBx promoted the tumor proliferation and invasion of HepG2 HCC cells, enhanced the ability to sorafenib resistance, and inhibited apoptosis.
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Objective@#To investigate the effects and mechanism of hepatitis B virus x protein (HBx) on human hepatocellular carcinoma cells proliferation.@*Methods@#Eukaryotic expression vector HBx-pEGFP-C1 was constructed. HepG2 cells were transfected transiently using Lipofectamine 2000. HBx expression in transfected cells were measured by RT-PCR and Western blot. Cells proliferation and apoptosis were detected by using growth curves and TUNEL staining. The protein levels of caspase-3, p-p38, p-Akt and p-JNK were measured by Western blot.@*Results@#HBx was successfully expressed in HepG2 cells. Growth curve result showed that HBx promoted cell proliferation (t=-0.8999, P=0.012). Compared with control group, the levels of p-p38(24 h) (t=- 11.058, P=0.0004) and p-JNK(48 h) (t=- 15.022, P=0.0001) in HBx-pEGFP-C1 group were increased significantly. There is no significant difference between the two groups′ apoptosis.@*Conclusions@#Transient overexpression of HBx promoted human hepatic carcinoma cells proliferation and activated the p38 and JNK signalling pathway.
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Objective@#To study the interaction between hepatitis B virus X protein(HBx) and mitochondrial elongation factor G1 (EFG1) in yeast cells or hepatoma cells.@*Methods@#After verification the interaction between HBx and EFG1 by CytoTrap yeast two-hybrid system, EFG1 genome was amplified by means of polymerase chain reaction(PCR) and cloned into the pcDNA3.1/myc-His(-)A vector, following verification by sequencing. Expression of HBx and EFG1 protein was verified in Huh7 cells. Then the recombinant vector pcDNA3.1/myc-His(-)A-EFG1 and pFLAG-CMV-2-HBx were transfected into Huh7 cells; 48 h later, the cells were lysed. The direct interaction between HBx and EFG1 was further confirmed by the Co-immunoprecipitation (Co-IP) assay.@*Results@#The interaction between HBx and EFG1 was successfully verified by CytoTrap yeast two-hybrid system. The recombined plasmid pcDNA3.1/myc-His(-)A-EFG1 was obtained. Furthermore, Co-IP assay was used to confirm the interaction between HBx and EFG1 in Huh7 cells.@*Conclusions@#The direct interaction between HBx and EFG1 was confirmed. Therefore our findings provide experimental basis for the influence of HBx protein on the expression of mitochondrial protein and provide new insights into the pathogenesis of HBx in the development of hepatocellular carcinoma.
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Objective To investigate the effect of occult HBV infection (OBI) on carcinogenesis of cryptogenic hepatocellular carcinoma.Methods Samples of hepatocellular carcinoma (HCC) and pericarcinomatous tissues obtained after hepatectomy from January 2011 to November 2013 at the Third Affiliated Hospital of Sun Yat-Sen University were collected.They were divided into two groups:the cryptogenic HCC group (the CH group,n =26) and the HBV related HCC group (the HH group,n =40).These samples were compared with the normal liver tissues obtained in 30 patients.HBV DNA was identified by the nested polymerase chain reaction and the immunohistochemical method was taken to examine the hepatitis B virus X protein (HBx) and Yes-associated protein (YAP) expressions.Results OBI was identified in 20 (77.8％) cryptogenic HCC patients and 8 (26.7％) in the control group.There was a significant difference between the two groups (x2 =14.072,P ＜ 0.05).HBV DNA was detected in all the HBV-related HCC patients.The HBx protein expression was mainly located in the cytoplasm of liver cells and liver cancer cells,but YAP was expressed in the nucleus.Both of them showed diffuse brown or tan particles.In the HH group and the CH group,the positive expression rates of HBx protein in the tumorous tissues were 80.0％ and 90.0％,respectively,and 85.0％ and 82.5％ in the nontumorous tissues,but only in 40.0％ in the control group.The positive expression rates of YAP in the tumorous tissues were 65.0％ and 67.5％,respectively,15.0％ and 20.0％ in the nontumorous tissues,respectively,but only in 12.5％ in the control group.The HBx expression in the cancerous tissues and para-cancerous tissues of the HH group and the CH group showed no significant difference (P ＞ 0.05),but the YAP expression in the tumor tissues was significantly higher than that in the nontumorous tissues (P ＜ 0.05).The HBx and YAP expressions in the HH group were comparable to the CH group (P ＞ 0.05).However,their expressions in the cancerous tissue of the HH group and the CH group were significantly higher than in the normal liver tissues (P ＜ 0.05).Conclusion A high prevalence of HBV infection was observed in HBsAg-negative HCC and the high expressions of HBx and YAP might be involved in the process of cryptogenic hepatocellular carcinoma.
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Objective To explore the effects and mechanisms of hepatitis B virus-X protein (HBx) on invasion and migration of hepatocellular carcinoma (HCC) cells.Methods The retrospective cohort study was conducted.The clinicopathological data of 30 patients with liver tumor (20 with HCC and 10 with benign tumor of liver) who were admitted to the Affiliated Hospital of Xuzhou Medical College between July 2014 and July 2015 were collected.HCC tissues of 20 patients with HCC (with history of HBV infection) were collected by surgical resection and peritumoral normal tissues (outside of tumor capsule) of 10 patients with benign tumor of liver (without history of HBV infection) were collected.The expressions of epidermal growth factor receptor 3 (ErbB3)in HCC tissues and peritumoral normal tissues were detected by immunohistochemistry (IHC).The relative expressions of ErbB3 and HBx in HCC tissues and peritumoral normal tissues were detected by Western blot,and relative expressions of ErbB3 in HepG2 of which green fluorescent protein (GFP) and GFP-HBx were respectively transfected were detected.The relative expressions of ErbB3 mRNA in HepG2 transfected by GFP and GFP-HBx were detected by real-time polymerase chain reaction (RT-PCR).The migration and invasion of HepG2 were respectively detected by Transwell assay with and without matrix.The measurement data with normal distribution were represented as $± s.The comparisons between groups were evaluated with the independent-sample t test.Correlation analysis was done by the Pearson test.Results (1) The expressions of ErbB3 were detected by IHC:relative value of mean optical density (MOD) of ErbB3 in HCC tissues of 20 patients with HCC and peritumoral normal tissues of 10 patients with benign tumor of liver were 2.54± 1.33 and O.99±0.29,respectively,with a statistically significant difference (t =6.542,P ＜ 0.05).(2) The relative expressions of ErbB3 and HBx were detected by Western blot:relative expressions of ErbB3 and HBx were respectively 0.79±0.13,1.10±0.28 in HCC tissues of 10 patients with HCC and 1.07±0.17,0 in peritumoral normal tissues of 10 patients with benign tumor of liver,with statistically significant differences (t =3.229,19.486,P＜0.05).The results of Pearson test showed that there was a positive correlation of expression between ErbB3 and HBx in HCC tissues (r=O.637,P＜ 0.05).(3) The relative expressions and transcriptional levels of ErbB3 were detected by Western blot and RT-PCR:relative expressions of ErbB3 in HepG2 of which GFP and GFP-HBx were respectively transfected were O.75±0.11 and 1.10±0.10,respectively,with a statistically significant difference (t=4.291,P＜0.05).The relative expressions of ErbB3 mRNA in HepG2 of which GFP and GFP-HBx were respectively transfected were O.38±0.03 and O.94±0.07,respectively,with a statistically significant difference (t=11.703,P＜O.05).(4) The effects of ErbB3 on migration and invasion of HepG2:numbers of transmenbrane cell in HepG2 of which His and His-ErbB3 were respectively transfected by Transwell assay with matrix were respectively 271± 18 and 463± 31,respectively,with a statistically significant difference (t =8.202,P＜0.05).Numbers of transmenbrane cell in HepG2 of which His and His-ErbB3 were respectively transfected by Transwell assay without matrix were respectively 315±38 and 549±34,respectively,with a statistically significant difference (t =8.310,P＜0.05).Conclusion HBx protein can promote the invasion and migration of hepatocellular carcinoma cells through up-regulating expressions of ErbB3 protein.
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Objective To investigate the effect of hepatitis B virus X (HBx)protein on the apoptosis of placental trophoblastic cells and its potential mechanism.Methods A pcDNA3.1 expression vector of HBx gene was constructed and transfected into JEG-3 and HTR-8 human placental trophoblastic cell lines,respectively.After transfection for 48 h,RT-PCR and immunofluorescence analyses were made to detect HBx mRNA and protein expressions.Flow cytometry was used to detect the early apoptosis status of JEG-3 and HTR-8 cells.The expressions of PI3K and p-Akt were detected by immunofluorescence and Western blotting.Results After transfection for 48 h,RT-PCR and immunofluorescence analyses showed that HBx mRNA and protein expressions were detected in JEG-3 and HTR-8 cells.Flow cytometry revealed that early apoptosis of JEG-3 and HTR-8 cells was reduced by pcDNA-HBx transfection (P <0.05).Immunofluorescence and Western blotting showed that PI3K and p-Akt were significantly upregulated in HTR-8 cells (P < 0.05 ).Conclusion HBx gene can be transfected into JEG-3 and HTR-8 human placental trophoblastic cell lines,respectively.After the transfection,the early apoptosis of JEG-3 and HTR-8 cells is reduced.Its inhibition on apoptosis is related to the activation of the PI3K/Akt signaling path-way.
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Objective To investigate the effect of hepatitis B virus X (HBx)protein on the apoptosis of placental trophoblastic cells and its potential mechanism.Methods A pcDNA3.1 expression vector of HBx gene was constructed and transfected into JEG-3 and HTR-8 human placental trophoblastic cell lines,respectively.After transfection for 48 h,RT-PCR and immunofluorescence analyses were made to detect HBx mRNA and protein expressions.Flow cytometry was used to detect the early apoptosis status of JEG-3 and HTR-8 cells.The expressions of PI3K and p-Akt were detected by immunofluorescence and Western blotting.Results After transfection for 48 h,RT-PCR and immunofluorescence analyses showed that HBx mRNA and protein expressions were detected in JEG-3 and HTR-8 cells.Flow cytometry revealed that early apoptosis of JEG-3 and HTR-8 cells was reduced by pcDNA-HBx transfection (P <0.05).Immunofluorescence and Western blotting showed that PI3K and p-Akt were significantly upregulated in HTR-8 cells (P < 0.05 ).Conclusion HBx gene can be transfected into JEG-3 and HTR-8 human placental trophoblastic cell lines,respectively.After the transfection,the early apoptosis of JEG-3 and HTR-8 cells is reduced.Its inhibition on apoptosis is related to the activation of the PI3K/Akt signaling path-way.
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Objective@#To investigate the influence of hepatitis B virus X gene (HBx) on apoptosis of hepatic cells mediated by Fas in HePG2 cells.@*Methods@#HBx eukaryotic vector pcDNA3.1(+)-X was transfected into HEPG2 cells with lipofectamine, and the null vector pcDNA3.1(+) and untransfected HEPG2 were used as normal controls. The cells were collected 72 h after transfection, and the expression of HBx mRNA and protein was determined using RT-PCR and Western blot, respectively. The mRNA expression of apoptosis-related genes Bcl-2 and Bax mRNA was also determined using RT-PCR. Cytotoxicity and apoptosis were evaluated using CCK-8 and flow cytometry, respectively, after HepG2-HBx and HepG2-3.1 cells were treated with stimulatory monoclonal antibody anti-Fas CH11. The t test was used for pairwise comparison.@*Results@#The cell line HepG2-HBx was successfully established, as confirmed by RT-PCR and Western blot, and RT-PCR results showed that HepG2-HBx cells had significantly higher expression of Bcl-2 mRNA than HepG2-3.1 and HepG2 cells (P < 0.05), but had significantly lower expression of Bax mRNA than HepG2-3.1 and HepG2 cells (P < 0.05); CCK-8 and flow cytometry showed that anti-Fas CH11 had a lower cytotoxicity to HepG2-HBx cells and allowed for a lower apoptosis rate of HepG2-HBx cells compared with HepG2-3.1 and HepG2 cells.@*Conclusions@#HBx can inhibit apoptosis of hepatic cells mediated by the Fas pathway.
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BACKGROUND/AIMS: Hepatitis B viral protein X (HBx) is implicated in the pathogenesis of hepatocellular carcinoma (HCC) as well as the elevation of heat shock proteins (HSPs) after hepatitis B virus (HBV) infection. We thus investigated the anticancer effects of an HSP90 inhibitor 17-Dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG) in HBx-transfected hepatocellular carcinoma cells. METHODS: pcDNA-HBx was made by inserting the HBx gene derived from the HBV-infected patient into pcDNA3.1 using the restriction enzymes (XbaI/HindIII). HBx-expressing HepG2 cells were then generated by transfecting HepG2 cells with pcDNA containing HBx gene. To compare the anticancer effects of 17-DMAG between pcDNA-HBx transfected HepG2 cells and the control cells (pcDNA-transfected HepG2 cells), we performed various molecular studies, including Ez-cytox proliferation assay, Western blot analysis, and flow cytometry. RESULTS: 17-DMAG inhibited the proliferation of pcDNA-HBx transfected HepG2 cells better than control cells (P<0.05). After treating with a various concentration of 17-DMAG (50–1,000 nM), pcDNA-HBx transfected HepG2 cells exhibited higher expression of pro-apoptotic proteins (c-caspase-3, c-caspase-8, and c-caspase-9) than did control cells (P<0.05). pcDNA-HBx transfected HepG2 cells showed higher activities of caspase-3, caspase-8, and caspase-9 than did control cells (P<0.05). Finally, we found that the expression of pro-apoptotic proteins (PARP and c-caspase-3) was considerably decreased by the use of a caspase inhibitor suggesting that 17-DMAG induces the cell death of HepG2 cells caspase-dependently. CONCLUSIONS: Our study strongly suggests that 17-DMAG has antiviral effects against HBV as well as anticancer effects against HepG2 cells. Thus, the application of 17-DMAG appears to be particularly advantageous to the HCC patients related with HBV infection.
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Humanos , Apoptosis , Proteínas Reguladoras de la Apoptosis , Western Blotting , Carcinoma Hepatocelular , Caspasa 3 , Caspasa 8 , Caspasa 9 , Caspasas , Muerte Celular , Citometría de Flujo , Proteínas de Choque Térmico , Células Hep G2 , Virus de la Hepatitis B , Hepatitis B , Hepatitis , TransfecciónRESUMEN
Liver cancer occurs very frequently worldwide and hepatocellular carcinoma (HCC) accounts for more than 80% of total primary liver cancer cases. In this study, the anticarcinogenic effects of resveratrol against hepatitis B virus (HBV)-induced HCC were investigated by using HBV X-protein-overexpressing Huh7 (Huh7-HBx) human hepatoma cells. MTT assay showed that resveratrol decreased cell viability. Fluorescence-activated cell-sorter analysis showed that resveratrol induced G1 cell cycle arrest without increasing the sub-G1 phase cell population. Therefore, we evaluated its effect on regulation of cyclin D1, which is critically involved in G1/S transition. Resveratrol lowered cyclin D1 transcription. Western blot analysis of the effects of resveratrol on upstream cyclin D1 transcriptional signaling, extracellular signal-related kinase (ERK), p90(RSK), Akt, and p70(S6K) revealed inhibition of Akt but not the ERK signaling pathway. Collectively, the results indicate that resveratrol inhibits Huh7-HBx proliferation by decreasing cyclin D1 expression through blockade of Akt signaling. We investigated the anticarcinogenic effect and mechanism of resveratrol in xenograft model mice implanted with Huh7-HBx cells. Intraperitoneal resveratrol injection reduced tumor size in the mice. Expression of survivin was reduced, but cyclin D1 was not affected. The results demonstrate that resveratrol treatment may help manage HBV-induced HCC by regulating survivin.
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Animales , Humanos , Ratones , Anticarcinógenos , Western Blotting , Carcinoma Hepatocelular , Supervivencia Celular , Ciclina D1 , Puntos de Control de la Fase G1 del Ciclo Celular , Virus de la Hepatitis B , Hepatitis B , Hepatitis , Xenoinjertos , Neoplasias Hepáticas , Fosfotransferasas , Proteínas Quinasas S6 Ribosómicas 90-kDaRESUMEN
Objective To investigate the influence of hepatitis B virus X (HBx) protein on the activity of NLRP3 inflammasome as well as the mechanism of accelerating HBV-related hepatocellular carcinoma (HCC).Methods The HepG2 cell strains were divided into the 5 groups:blank control group (without plasmid transfection),empty vector group [transfected with pE green fluorescent protein (GFP)-N1 vector plasmid],fulllength HBx protein group (transfected with pEGFP-N1-X plasmid),HBx1-127 group (transfected with pEGFP-N1-X1-127 plasmid),HBx1-101 group (transfected with pEGFP-N1-X1-101 plasmid).(1) The expressions of HBx protein and NLRP3 inflammasome were detected by Western blot [Lipopolysaccharide (LPS) + ATP intervention was performed in the blank control group].(2) The HepG2 cells in the full-length HBx protein group were respectively intervened by glibenclamide and ammonium pyrrolidinedithiocarbamate (APDC),and the expressions of IL-1β and IL-18 were detected by enzyme-linked immunosorbent assay (ELISA).(3) The expressions of reactive oxygen were detected by flow cytometry.The measurement data with normal distribution were presented by (x) ± s.The one-way ANOVA was adopted in the comparison among groups while the t test was used in the pairwise comparison.Results (1) The results of Western blot showed:① the relative expressions of HBx recombinant plasmid fusion protein inside the HepG2 cells in the blank control group,empty vector group,full-length HBx protein group,HBx1-127 group and HBx1-101 group were 0.07 ±0.03,0.92 ±0.13,0.84 ±0.11,0.30 ±0.06 and 0.29 ± 0.05,respectively.The expressions in the HBx1-127 group and the HBx1-101 group represented the expressions of HBx1-127 protein and HBx1-101 protein.There were statistically significant differences among the 5 groups (F =61.790,P ＜ 0.05).The relative expression of full-length HBx protein group was significantly different from that of blank control group,HBx1-127 group and HBx1-101 group (t =12.070,7.465,7.801,P ＜0.05).There was no statistically significant difference between full-length HBx protein group and empty vector group (t =0.867,P ＞0.05) and between the HBx1-127group and HBx1-101 group (t =0.146,P＞0.05).② The relative expression of NLRP3 inflammasome protein inside the HepG2 cells in the blank control group,full-length HBx protein group,HBx1-127 group,HBx1-101 group and LPS + ATP group were 0.29 ±0.06,0.83 ±0.14,0.27 ±0.06,0.27 ± 0.05 and 0.90 ± 0.16,respectively,with a statistically significant difference among the 5 groups (F =29.550,P ＜ 0.05).The relative expression of NLRP3 inflammasome protein of LPS + ATP group was significantly different from that of blank control group,HBx1-127 group and HBx1-101 group,respectively (t =6.310,6.565,6.741,P ＜0.05).There were statistically significant differences between the full-length HBx group and the HBx1-127 group or HBx1-101 group (t =6.381,6.584,P ＜ 0.05) and no statistically significant difference between LPS + ATP group and full-length HBx protein group (t =0.580,P ＞ 0.05).(2) The results of ELISA showed:①) the expression of IL-1β inside the HepG2 cells in the blank control group,full-length HBx protein group,HBx1-127 group,HBx1-101 group and LPS + ATP group was (87 ± 9)pg/mL,(587 ±56)pg/mL,(125 ±12) pg/mL,(113 ± 13) pg/mL and (677 ± 74) pg/mL,respectively,with a statistically significant difference among the 5 groups (F =139.010,P ＜ 0.05).The expression of IL-1 β of LPS + ATP group was significantly different from that of blank control group,HBx1-127 group and HBx1-101 group (t =13.691,12.752,13.001,P ＜0.05).The expression of IL-1β of full-length HBx group was significantly different from that of the HBx1-127 group and the HBx1-101 group (t =14.051,14.283,P ＜ 0.05).There was no statistically significant difference between the LPS + ATP group and the full-length HBx protein group (t =1.691,P ＞0.05).The expression of IL-18 in the blank control group,full-length HBx protein group,HBx1-127 group,HBx1-101 group and LPS + ATP group was (43 ±8)pg/mL,(252 ±38)pg/mL,(70 ± 13)pg/mL,(63 ± 10)pg/mL and (263 ±48)pg/mL,respectively,with a statistically significant difference among the 5 groups (F =44.010,P ＜0.05).The expression of IL-18 of LPS + ATP group was significantly different from that of blank control group,HBx1-127 group and HBx1-101 group,respectively (t =7.848,6.722,7.065,P ＜ 0.05).The expression of IL-18 of full-length HBx group was significantly different from that of HBx1-127 group and HBx1-101 group (t =7.882,8.331,P ＜ 0.05).There was no statistically significant difference between LPS + ATP group and full-length HBx group (t =0.326,P ＞ 0.05).②The expressions of IL-1β and IL-18 in the HepG2 cells of the full-length HBx protein were (587 ± 91)pg/mL and (243 ± 22) pg/mL before the addition of glibenclamide,(115 ± 17) pg/mL and (90 ± 12) pg/mL after the addition of glibenclamide,respectively,with statistically significant differences before and after the addition of glibenclamide (t =8.800,10.566,P ＜ 0.05).The expressions of IL-1β and IL-18 in the HepG2 cells of the full-length HBx protein were (573 ± 89) pg/mL and (252 ± 24) pg/mL before the addition of APDC,(124 ±21)pg/mL and (116 ± 15)pg/mL after the addition of APDC,respectively,with statistically significant differences before and after the addition of APDC (t =8.516,8.269,P ＜ 0.05).(3) The results of flow cytometry showed that the relative expression of reactive oxygen in the HepG2 cells in blank control group,fulllength HBx protein group and LPS + ATP group were 66 ± 14,275 ± 54 and 388 ± 88,with statistically significant differences among the 3 groups (F =22.130,P ＜ 0.05) and between the full-length HBx protein group or LPS +ATP group and blank control group (t =6.489,6.256,P ＜ 0.05).There was no statistically significant difference between full-length HBx protein group and LPS + ATP group (t =1.887,P ＞ 0.05).Conclusion HBx protein may play an important role in the occurrence and development of HBV-related HCC by activating NLRP3 inflammasome through inducing reactive oxygen generation in the HepG2 cells.
RESUMEN
Hepatic cellular cancer (HCC) is one of the most common cancers in the world, which is a serious threat to human health and life quality. More than 700 000 people die of HCC each year on average, and its incidence increases in many countries. Chronic hepatitis B virus (HBV) infection has been identified as a dominant risk factor for HCC. The pathogenesis of HBV-induced hepatocarcinogenesis is, however, incom-pletely understood. Evidence currently available supports a key role of the HBV X protein (HBx) in the cancer transformation and malignant tumor metastasis. HBx is a multifunctional regulator that may cooperate with the host factors to exert its effects on transcription, signal transduction, cell cycle progression, apoptosis, protein degradation, expression of oncogene and anti-oncogene. This review presents the current knowledge in the molecular pathogenesis of HBx in the induction of HCC.
RESUMEN
Objective To examine the role of c-Src activation in hepatitis B virus X (HBx) protein induced epithelial-mesenchymal transition (EMT) in liver cancer.Methods SMMC-7721 liver cancer cells were transfected with HBx gene to induce EMT and the activated c-Src expression was evaluated by Western blot.Both the morphological changes and the epithelial and mesenchymal markers expression (real-time PCR,western blot and immunocytochemistry) of HBx-transfected SMMC-7721 cell treated by c-Src kinase inhibitor PP2 and negative control PP3 were observed and compared,respectively.Results The activated c-Src expression in HBx gene transfected SMMC-7721 cells was significantly increased compared to that in mock transfected cells,c-Src kinase inhibitor PP2 could enable the HBx-transfected SMMC-7721 cells to transmit from spindle-like shape to original epithelial morphology.Western blot and immunocytochemistry confirmed that the expression of epithelial markers and mesenchymal markers almost returned to the levels of parental cells,indicating the mesenchymal-epithelial transition.Conclusions c-Src activation plays a key role in the process of EMT induced by HBx protein in SMMC-7721 cells.
RESUMEN
Background and purpose:Hepatitis B virus X protein (HBx) and hypoxia inducible factor-1α(HIF-1α) play key roles in hepatocarcinogenesis and the development of hepatocellular carcinoma. Positive correlation on the expression of these 2 proteins in hepatocellular carcinoma tissues has been found, whereas the underlying mechanisms have not been fully elucidated. This study focused on the role of HBx in regulating HIF-1α and the underlying mechanisms in hepatocellular carcinoma cells. Methods:The expression plasmids were transfected into Huh7 cells with LipofectemineTM 2000. Western blot analysis was applied to detect the expressions of HIF-1αand HIF-1β protein. The transcriptional activity of HIF-1α was detected by the commercial analysis kits. The mRNA levels of HIF-1αand its target genes, including vascular endothelial growth factor (VEGF) and multi-drug resistance gene 1 (MDR1), were detected by quantitative real-time PCR (qRT-PCR). Immunoprecipitation analysis was applied to detect the interaction of HIF-1α, HBx and protein von Hippel-Lindau (pVHL). Results:Huh7 cells transfected with HBx plasmid led to sharp increase of HIF-1αprotein and transcriptional activity, as well as the mRNA of VEGF and MDR1 (P0.05). Meanwhile, HBx also signiifcantly impaired the function of pVHL in mediating the degradation of HIF-1αby ubiquitin hydrolase. This finding was further confirmed by the immunoprecipitation analysis, which showed that HBx could directly bind to pVHL, but not to HIF-1α. Conclusion:HBx may inhibit the inter-activation between pVHL and HIF-1αthrough directly binding to pVHL, and thus enhance the stability and transcriptional activity of HIF-1α.
RESUMEN
HBx gene is a multifunctional regulator,which has extensive trans-activating effects,and can activate transcription factors,inhibit DNA repair and regulate cell proliferation,differentiation and apoptosis.In recent years,the role of HBx gene in pathogenesis of hepatitis B virus-associated glomemlonephritis (HBV-GN) has been extensively studied,and the results show that HBx can promote glomerular mesangial cell proliferation,and induce damage or apoptosis of podocytes and renal tubular epithelial cells.This paper reviews the research progress on biological characteristics of HBx and its role in pathogenesis of HBV-GN.