ERK1/2-HNF4α axis is involved in epigallocatechin-3-gallate inhibition of HBV replication.

Epigallocatechin gallate (EGCG), a major polyphenol in green tea, exhibits diverse biological activities. Previous studies show that EGCG could effectively suppress HBV gene expression and replication, but the role of EGCG in HBV replication and its underlying mechanisms, especially the signaling pathways involved, remain unclear. In this study we investigated the mechanisms underlying EGCG inhibition on HBV replication with a focus on the signaling pathways. We showed that EGCG (12.5-50 µM) dose-dependently inhibited HBV gene expression and replication in HepG2.2.15 cells. Similar results were observed in HBV mice receiving EGCG (25 mg· kg-1· d-1, ip) for 5 days. In HepG2.2.15 cells, we showed that EGCG (12.5-50 µM) significantly activate ERK1/2 MAPK signaling, slightly activate p38 MAPK and JAK2/STAT3 signaling, while had no significant effect on the activation of JNK MAPK, PI3K/AKT/mTOR and NF-κB signaling. By using specific inhibitors of these signaling pathways, we demonstrated that ERK1/2 signaling pathway, but not other signaling pathways, was involved in EGCG-mediated inhibition of HBV transcription and replication. Furthermore, we showed that EGCG treatment dose-dependently decreased the expression of hepatocyte nuclear factor 4α (HNF4α) both at the mRNA and protein levels, which could be reversed by pretreatment with the ERK1/2 inhibitor PD98059 (20 µM). Moreover, we revealed that EGCG treatment dose-dependently inhibited the activity of HBV core promoter and the following HBV replication. In summary, our results demonstrate that EGCG inhibits HBV gene expression and replication, which involves ERK1/2-mediated downregulation of HNF4α.These data reveal a novel mechanism for EGCG to inhibit HBV gene expression and replication.

Study on Cellular Uptake Mechanism of HepG2.2.15 Cells to Nanoparticles Co-loaded with Syringopicroside and Hydroxytyrosol / 中国中医药信息杂志

Objective To investigate the uptake mechanism of HepG2.2.15 cells to the nanoparticles co-loaded with syringopicroside and hydroxytyrosol (SH-NPs). Methods The nanoparticles were prepared by using a nanoprecipitation method with mPEG-PLGA as nano-carrier co-loaded with syringopicroside and hydroxytyrosol. The uptake mechanism of HepG2.2.15 cells to SH-NPs was studied by fluorescence microscopy and flow cytometry using fluoresceineisothiocyanate (FITC) as a fluorescent marker. Results With colchicine as the inhibitor, the incubation time ranged from 0.5 to 24 h, the percentage of positive cells increased from 1.9% to 56.4%; When the drug concentration was 125, 250 μg/mL and 500 μg/mL, the positive cell percentages were 4.9%, 3.4% and 3.9%. With chloroquine as the inhibitor; the incubation time ranged from 0.5 to 24 h, the percentage of positive cells increased from 7.4% to 55.4%; When the drug concentration was 125, 250 and 500 μg/mL, the percentage of positive cells was 19.5%, 22.5% and 27.6%. Conclusion Colchicine and chloroquine have an inhibitory effect on HepG2.2.15 cells uptake, and the uptake of SH-NPs in HepG2.2.15 cells was positively correlated with drug concentration and incubation time. It can be concluded that the uptake mechanism of HepG2.2.15 cells to SH-NPs was nonspecific adsorption endocytosis.

Protocatechuic acid inhibits hepatitis B virus replication by activating ERK1/2 pathway and down-regulating HNF4α and HNF1α in vitro.

AIMS: Protocatechuic acid (PCA) is a phenolic compound found in many antiviral Chinese herbal medicines. HNF4α and HNF1α, the members of hepatocyte nuclear factor (HNF) family, play an important regulatory role in the gene transcription of hepatitis B virus (HBV). Previous studies found that PCA inhibited HBV antigen secretion and HBV DNA replication in HepG2.2.15 cells, but its anti-HBV mechanism has not been fully understood. We aim to illustrate the anti-HBV mechanism of PCA. MATERIALS AND METHODS: MTT was used to estimate cytotoxicity. The content of HBsAg or HBeAg was detected using an enzyme-linked immunosorbent assay kit. HBV DNA in cell-free culture media was detected by PCR kit. HNF1α and HNF4α mRNA expression was detected by real-time PCR. HNF1α, HNF4α and ERK1/2 protein expression was detected by western blotting and HBV promoter activity was tested by luciferase reporter assay. KEY FINDINGS: Our results demonstrated that PCA inhibited the gene transcription and protein translation of HNF1α and HNF4α in Huh7 and HepG2.2.15 cells, as well as the promoter activities of HBV X and preS1 in Huh7 cells transfected with the luciferase reporter plasmid of HBV promoter. Further study suggested that PCA induced the phosphorylation of extracellular-signal-related kinase (ERK) 1/2, and thereby inhibited HNF4α and HNF1α expression in HepG2.2.15 cells to exert its antiviral activity. SIGNIFICANCE: To our knowledge, this study is the first to reveal the anti-HBV mechanism of PCA. Our results demonstrate that PCA inhibits HBV replication by activating ERK1/2 pathway and subsequently down-regulating HNF4α and HNF1α in HepG2.2.15 cells.

Discovery and mechanism of action of Novel Baicalein modified derivatives as potent antihepatitis agent.

Anti-hepatitis B virus (HBV) activity was evaluated in HepG2 2.2.15 cells by novel Baicalein derivatives. The result showed that compounds 4k and 4h was found to be effective anti-HBV agent. Further, the effect of compounds 4k and 4h showed dose-dependent inhibition of HBV-DNA as compared to control together with significant inhibition of HbeAG and HbsAG expression in the tested dose. Both compounds showed considerable affinity against the HepG2.2.15 cells. Moreover, the docking study of compound 4k was carried out with HLA molecule showing excellent intermolecular interactions with the receptor via creation of numerous bonds with Ser5, Thr27, Asp29 and Phe8. The compound 4k showed significant effect on the HO-1 expression in HepG2.2.15 cells together with excellent anti-HBV activity in transgenic mouse confirmed by biochemical and histopathological parameters. Compound 4k also showed excellent pharmacokinetic profile in experimental animal and thus, provide a novel class of potent anti-HBV agents.

Classical drug resistance mutations of HepG2.2.15 cells persistently induced by appropriate concentrations of adefovir / 解放军医学杂志

Objective To observe whether the classic drug-resistant mutations can be induced in various concentrations of adefovir (ADV)-treated HepG2.2.15 cells persistently and explore the mechanism for emergence of drug resistance.Methods HepG2.2.15 cells were cultured continually in 12-well plates with medium containing 0,0.01,0.1,1.0μmol/L concentration of ADV,and passaged every 3 days up to the 110th generations.The intracellular and supernatant HBV DNA was extracted every 10 generations.Intracellular HBV cccDNA was amplified by plasmid-safe ATP dependent DNase (PSAD) digestion in combination with rolling circle amplification and gap-spanning semi-nested PCR assay.And the RT region of supernatant HBV DNA was amplified by one-tube nested PCR assay.Then the classic drug-resistant mutations of the RT region of intracellular cccDNA and supernatant HBV DNA were analyzed using direct PCR sequencing combined with clonal sequencing (more than 20 clones/sample).Results HBV DNA stably replicated in ADV-untreated cells (control group).The intracellular total DNA and cccDNA levels,supernatant HBV DNA level decreased continuously with the prolonged ADV culture duration in 0.01 μmol/L and 0.1μmol/L ADV group.Drug resistant mutations were not detected up to the 110th generation in 0.01 μmol/L ADV group;while rtA181V+N236T mutations were detected at the110th generation in 0.1μmol/L ADV group.The 1.0μmol/L ADV group was ceased of culture at the 15th generation due to inhibited cell growth.Conclusion HBV cccDNA exists in HepG2.2.15 cells,and the classical drug-resistant mutations of rtA181V+N236T could be induced by proper concentration of ADV.

Anti-HBV Activities of Three Compounds Extracted and Purified from Herpetospermum Seeds.

The goal of this research was to evaluate the anti-hepatitis B virus (HBV) activities of three compounds extracted and purified from Herpetospermum seeds (HS) on HepG2.2.15 cells. Herpetin (HPT), herpetone (HPO), and herpetfluorenone (HPF) were isolated from HS and identified using HR-ESI-MS and NMR. Different concentrations of the drugs were added to the HepG2.2.15 cells. Cell toxicity was observed with an MTT assay, cell culture supernatants were collected, and HBsAg and HBeAg were detected by ELISA. The content of HBV DNA was determined via quantitative polymerase chain reaction (PCR) with fluorescent probes. The 50% toxicity concentration (TC50) of HPF was 531.48 µg/mL, suggesting that this species is less toxic than HPT and HPO. HPT and HPF showed more potent antiviral activities than HPO. The 50% inhibition concentration (IC50) values of HPF on HBsAg and HBeAg were 176.99 and 134.53 µg/mL, respectively, and the corresponding therapeutic index (TI) values were 2.66 and 3.49, respectively. HPT and HPF were shown to significantly reduce the level of HBV DNA in the HepG2.2.15 culture medium compared to the negative control. This initial investigation of the anti-HBV constituents of HS yielded three compounds that revealed a synergistic effect of multiple components in the ethnopharmacological use of HS.

[Thymopolypeptides combined with matrine type alkaloids suppress HBV replication].

To investigate the antiviral effect of thymopolypeptides combined with 4 kinds of matrine type alkaloids on HepG2.2.15 cells, oxymatrine, sophocarpidine, sophocarpine, and sophoridine (at concentration of 0.2 mmol•L⁻¹ respectively) were respectively combined with thymopolypeptides (0.025, 0.1 g•L⁻¹), and after 48 h and 72 h treatment on HepG2.2.15 cells, the cells and supernatants were collected. The cells activity in various groups was determined by CCK-8 method to evaluate the toxic effects of the drugs on HepG2.2.15 cells. Enzyme linked immunosorbent assay (ELISA) was used to determine HBeAg and HBsAg levels in cellular supernatants. HBV DNA levels in cellular supernatants andcells were quantified with fluorogenic quantitative PCR method; and the expression level of IFN-α in supernatants was detected with CBA method. The results indicated that single thymopolypeptides at 0.025-0.4 g•L⁻¹ had no toxicity to cells. Thymopolypeptides in this concentration range combined with 0.2 mmol•L⁻¹ matrine type alkaloids also had no toxicity to cells. Anti-HBV activity of drug combination was better than that of alkali or thymopolypeptides alone. Thymopolypeptides at 0.025 g•L⁻¹ had better inhibitory effect than thymopolypeptides at 0.1 g•L⁻¹ on intracellular HBV DNA expression, but the inhibitory effect on supernatant HBeAg level was on the contrary. Anti-HBV activity was similar between alkaloids combined with 0.1 g•L⁻¹ and alkaloids combined with 0.025 g•L⁻¹. There was no statistical difference in anti-HBV effect between various combined groups (P<0.05). In general, 72 h anti-HBV effect was better than 48 h anti-HBV effect (P<0.05). The expression of IFN-α was increased after drug combination, with positive correlation to the changes of other four indicators (P<0.05). In conclusion, oxymatrine, sophocarpidine, sophocarpine and sophoridine combined with thymopolypeptides could inhibit HBsAg and HBeAg secretion in HepG2.2.15 cells and HBV DNA replication, and further promote the antiviral effect by promoting the expression of IFN-α.

[Effect and mechanism of danshensu on hepatitis B virus reverse transcriptase and antigen expression].

MTT assay was used in this study to investigate the inhibitory effect of danshensu on the activity of 2.2.15 cells among human hepatoma cell line (HepG2); indirect fluorescence labeling method was used to measure the changes of reactive oxygen levels in the cells; ELISA method was used to determine hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) levels in cellular supernatants; HBV DNA level was measured with fluorogenic quantitative PCR method. The inhibitory effect of danshensu on HBV RT(hepatitis B virus reverse transcriptase) was studied by using enzyme inhibition dynamics, and the effect of danshensu on secondary structure of HBV reverse transcriptase was monitored by using circular dichroism. The results showed that danshensu had a good inhibitory effect on the growth of HepG2.2.15 cells, with a half inhibitory concentration (IC50) of (15.35±2.43) µmol•L⁻¹; danshensu could significantly inhibit HBsAg and HBeAg expressions, and showed an inhibitory effect on HBV DNA replication. In addition, danshensu was an effective inhibitor for HBV reverse transcriptase [IC50 (21.32±2.43) µmol•L⁻¹]. The fluorescence labeling results showed that the reactive oxygen levels in the cells were increased with the increase of danshensu concentration. Circular dichroism analysis showed that danshensu could induce partial change of conformation of HBV reverse transcriptase and gradually increased α-helical content. These results indicated that danshensu could make the structure of the enzyme become closer by binding to HBV reverse transcriptase, which was not conducive to the formation of the active center, so it could finally decrease the activity of HBV reverse transcriptase. Such decrease in enzyme activity would directly affect the HBV DNA replication, and combined with the decrease of the antigen levels, the effect of danshensu on HBV was increased.

Effect and mechanism of danshensu on hepatitis B virus reverse transcriptase and antigen expression / 中国中药杂志

MTT assay was used in this study to investigate the inhibitory effect of danshensu on the activity of 2.2.15 cells among human hepatoma cell line (HepG2); indirect fluorescence labeling method was used to measure the changes of reactive oxygen levels in the cells; ELISA method was used to determine hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) levels in cellular supernatants; HBV DNA level was measured with fluorogenic quantitative PCR method. The inhibitory effect of danshensu on HBV RT(hepatitis B virus reverse transcriptase) was studied by using enzyme inhibition dynamics, and the effect of danshensu on secondary structure of HBV reverse transcriptase was monitored by using circular dichroism. The results showed that danshensu had a good inhibitory effect on the growth of HepG2.2.15 cells, with a half inhibitory concentration (IC₅₀) of (15.35±2.43) μmol•L⁻¹; danshensu could significantly inhibit HBsAg and HBeAg expressions, and showed an inhibitory effect on HBV DNA replication. In addition, danshensu was an effective inhibitor for HBV reverse transcriptase [IC₅₀ (21.32±2.43) μmol•L⁻¹]. The fluorescence labeling results showed that the reactive oxygen levels in the cells were increased with the increase of danshensu concentration. Circular dichroism analysis showed that danshensu could induce partial change of conformation of HBV reverse transcriptase and gradually increased α-helical content. These results indicated that danshensu could make the structure of the enzyme become closer by binding to HBV reverse transcriptase, which was not conducive to the formation of the active center, so it could finally decrease the activity of HBV reverse transcriptase. Such decrease in enzyme activity would directly affect the HBV DNA replication, and combined with the decrease of the antigen levels, the effect of danshensu on HBV was increased.

Thymopolypeptides combined with matrine type alkaloids suppress HBV replication / 中国中药杂志

To investigate the antiviral effect of thymopolypeptides combined with 4 kinds of matrine type alkaloids on HepG2.2.15 cells, oxymatrine, sophocarpidine, sophocarpine, and sophoridine (at concentration of 0.2 mmol•L⁻¹ respectively) were respectively combined with thymopolypeptides (0.025, 0.1 g•L⁻¹), and after 48 h and 72 h treatment on HepG2.2.15 cells, the cells and supernatants were collected. The cells activity in various groups was determined by CCK-8 method to evaluate the toxic effects of the drugs on HepG2.2.15 cells. Enzyme linked immunosorbent assay (ELISA) was used to determine HBeAg and HBsAg levels in cellular supernatants. HBV DNA levels in cellular supernatants andcells were quantified with fluorogenic quantitative PCR method; and the expression level of IFN-α in supernatants was detected with CBA method. The results indicated that single thymopolypeptides at 0.025-0.4 g•L⁻¹ had no toxicity to cells. Thymopolypeptides in this concentration range combined with 0.2 mmol•L⁻¹ matrine type alkaloids also had no toxicity to cells. Anti-HBV activity of drug combination was better than that of alkali or thymopolypeptides alone. Thymopolypeptides at 0.025 g•L⁻¹ had better inhibitory effect than thymopolypeptides at 0.1 g•L⁻¹ on intracellular HBV DNA expression, but the inhibitory effect on supernatant HBeAg level was on the contrary. Anti-HBV activity was similar between alkaloids combined with 0.1 g•L⁻¹ and alkaloids combined with 0.025 g•L⁻¹. There was no statistical difference in anti-HBV effect between various combined groups (P<0.05). In general, 72 h anti-HBV effect was better than 48 h anti-HBV effect (P<0.05). The expression of IFN-α was increased after drug combination, with positive correlation to the changes of other four indicators (P<0.05). In conclusion, oxymatrine, sophocarpidine, sophocarpine and sophoridine combined with thymopolypeptides could inhibit HBsAg and HBeAg secretion in HepG2.2.15 cells and HBV DNA replication, and further promote the antiviral effect by promoting the expression of IFN-α.

Construction of human microRNA-21 eukaryotic overexpression vector and its up-regulation of c-myc gene expression in HepG2 .2 .15 cells / 重庆医学

Objective To construct the miRNA‐21 eukaryotic overexpression vector pmR‐21 and to explore its regulation effect on the expression of c‐myc gene in HepG2 .2 .15 cells .Methods The miRNA‐21 precursor gene fragment pre‐miRNA‐21 was amplified by PCR ,then connected to the pmR‐mCherry plasmid vector after double enzyme digestion ,the accuracy of the recombi‐nant vector was verified by double enzyme digestion and sequencing ;then the recombinant vector was transfected into HepG2 .2 .15 cells ,the fluorescent protein expression was observed under the fluorescence microscopy at 24 h and the transfection efficiency was detected by flow cytometry ;the expression of miRNA‐21 was evaluated by real‐time quantitative PCR;at 72 h after transfection ,the expression levels of c‐myc gene were detected by RT‐PCR and Western blot ;CCK‐8 was used to detect the cell proliferation in each group .Results The double enzyme digestion and Western blot verified that the target gene fragment was inserted into the pmR‐mCherry vector;at 24 h after transfection ,intracellular strong fluorescence was seen ,the transfection efficiency was higher than 50% ;miRNA‐21 expression level of the pmR‐21 recombinant vector group was significantly increased;c‐myc gene expression was increased in the pmR‐21 recombinant vector group at 72 h after transfection ,the cell proliferation in the pmR‐21 recombinant group was faster than that in the control group(P<0 .05) .Conclusion The pmR‐21 eukaryotic overexpression vector is successfully con‐structed ,this recombinant vector can express miRNA‐21 stably ;miRNA‐21 can up‐regulate c‐myc gene expression ,c‐myc gene is one of miR‐21′s targets for playing a cancer‐promoting action .

Anti-hepatitis B virus activities of friedelolactones from Viola diffusa Ging.

BACKGROUND: Hepatitis B virus (HBV) infection is the major factor of causing hepatitis B, cirrhosis and liver cancer. Interferon and nucleoside drugs, the main drugs to treat HBV infection, have disadvantages of scavenge difficulty and drug resistance respectively. Viola diffusa Ging is used as a traditional Chinese herbal medicine for the treatment of hepatitis. PURPOSE: The aim of the study is to investigate the chemical constituents of Viola diffusa Ging and their anti-HBV activity. METHODS: Chemical constituents were extracted and purified by ethanol reflux extraction and chromatographic separation technology including D-101 Macroporous resin, silica gel, Sephadex LH-20 and preparative thin-layer chromatography. Their structures were elucidated on the basis of extensive NMR and MS data. Cytotoxicity and inhibiting effects on HBsAg and HBeAg secretion of HepG2.2.15 of all compounds except 10 were studied by MTT method and ELISA method. RESULTS: Three friedelolactones with naturally occurring seco-ring-A friedelane triterpenoids, 2ß-hydroxy-3, 4-seco-friedelolactone-27-oic acid (1), 2ß, 28ß-dihydroxy-3,4-seco-friedelolactone-27-oic acid (2) and 2ß, 30ß-dihydroxy-3,4-seco-friedelolactone-27-lactone (3), and a stigmastane, stigmast-25-ene-3ß,5α,6ß-triol (11) together with nine known compounds were isolated from the whole plant of Viola diffusa G. (Violaceae). Compounds 1-3, 9, 11, 12 exhibited significant activities of blocking both HBsAg and HBeAg secretion, and compound 4, 6, 7, 8 selectively inhibited HBeAg secretion while compound 13 selectively inhibited HBsAg secretion. IC50 values of compounds 1 and 2, 26.2 µM and 33.7 µM for HBsAg, 8.0 µM and 15.2 µM for HBeAg, was significantly lower than that of positive control lamivudine. CONCLUSION: Compounds 1-3, 11 are new compounds never reported before and the promising results demonstrate the potential of compound 1-3, 9, 11, 12 for the treatment of HBV infection.

HepG2.2.15 as a model for studying cell protrusion and migration regulated by S100 proteins.

Much of the difficulty in elucidating the precise function of S100 protein family has been attributed to functional redundancy and compensation by its conserved family members. In this study, we showed that seven S100 family members were almost totally undetectable in HepG2.2.15 cells, while all of them were highly expressed in its parental HepG2 cells. Re-expression of S100 proteins in HepG2.2.15 cells can partially rescue their defects in cell protrusion and migration through the regulation of cytoskeletons and adhesions. Thus, HepG2.2.15 can serve as a useful model for studying cell protrusion and migration regulated by S100 proteins.

Effects of xeroderma pigmentosum group D and p53 on replication of HBV / 中国病理生理杂志

AIM:To investigate the effects of xeroderma pigmentosum D ( XPD) and p53 on the replication of hepatitis B virus ( HBV) .METHODS:Recombinant plasmid pEGFP-N2/XPD and vacant vector plasmid pEGFP-N2 were transfected into HepG2.2.15 cells by liposome.On the next day, these cells were incubated with pifithrin-α, a p53 inhibi-tor, at a concentration of 20 μmol/L for 24 h.The cells were divided into 5 groups: blank control group, pEGFP-N2 group, pEGFP-N2/XPD group, pEGFP-N2/XPD+pifithrin-αgroup and pifithrin-αgroup.The mRNA expression of XPD, hepatitis B surface antigen ( HBsAg) , hepatitis B e antigen ( HBeAg) and hepatitis B virus X protein ( HBx) was detected by RT-PCR.The content of HBsAg and HBeAg in the supernatants of culture medium was measured by ELISA.The con-tent of HBV-DNA in the supernatants of culture medium was examined by fluorescence quantitative PCR.Using the method of bDNA, the content of HBV-DNA in the core particles was assessed.RESULTS:The expression of XPD mRNA was ele-vated by the transfection of recombinant plasmid pEGFP-N2/XPD.The increase in XPD expression significantly down-regu-lated the mRNA expression of HBsAg, HBeAg and HBx.The content of HBsAg and HBeAg in the supernatants of culture medium was significantly decreased by the increase in XPD expression.The results of fluorescence quantitative PCR showed that the content of HBV-DNA in the supernatants of culture medium was significantly down-regulated by the increase in XPD expression.bDNA results showed that the content of HBV-DNA in the core particles was significantly decreased by the increase in XPD expression.Pifithrin-αabolished the above-mentioned effects of XPD (all P<0.01).CONCLUSION:XPD inhibits the replication of HBV through p53 pathway.Therefore, XPD and p53 may be the targets for antiviral therapy of hepatitis B.

5'-triphosphate-siRNA activates RIG-I-dependent type I interferon production and enhances inhibition of hepatitis B virus replication in HepG2.2.15 cells.

Hepatitis B virus (HBV) infection often results in acute or chronic viral hepatitis and other liver diseases including cirrhosis and hepatocellular carcinoma. Current therapies for HBV usually have severe side effects and can cause development of drug-resistant mutants. An alternative and safe immunotherapeutic approach for HBV infection is urgently needed for effective anti-HBV therapy. In this study, we propose a new strategy for anti-HBV therapy that activates type-I interferon (IFN) antiviral innate immunity through stimulating pattern-recognition receptors with RNA interference (RNAi) using a 5'-end triphosphate-modified small interfering RNA (3p-siRNA). We designed and generated a 3p-siRNA targeting overlapping region of S gene and P gene of the HBV genome at the 5'-end of pregenomic HBV RNA. Our results demonstrated that 3p-siRNA induced a RIG-I-dependent antiviral type-I IFN response when transfected into HepG2.2.15 cells that support HBV replication. The 3p-siRNA significantly inhibited HBsAg and HBeAg secretion from HepG2.2.15 cells in a RIG-I-dependent manner, and the antiviral effect of 3p-siRNA was superior to that of siRNA. Furthermore, 3p-siRNA had more pronounced inhibition effects on the replication of HBV DNA and the transcription of mRNA than that of siRNA. Finally, 3p-siRNA displayed antiviral activity with long-term suppression of HBV replication. In conclusion, our findings suggest that 3p-siRNA could act as a powerful bifunctional antiviral molecule with potential for developing a promising therapeutic against chronic HBV infection.

Effects of SAHA on proliferation and apoptosis of hepatocellular carcinoma cells and hepatitis B virus replication.

AIM: To investigate the effects of suberoylanilide hydroxamic acid (SAHA) on proliferation and apoptosis of a human hepatocellular carcinoma cell line (HepG2.2.15) and hepatitis B virus (HBV) replication. METHODS: HepG2.2.15 cells were treated with different concentrations of SAHA. Cell morphology was examined by confocal laser scanning microscopy, and cell proliferation was determined using a MTT colorimetric assay. Flow cytometry was used to detect apoptosis and determine cell cycle phase, while hepatitis B surface antigen and hepatitis B e antigen content were measured using chemiluminescence. Reverse transcription polymerase chain reaction was performed to measure HBV DNA in cell lysate. RESULTS: Cell proliferation rates were significantly reduced by the addition of SAHA. The inhibitory effect of SAHA on cell proliferation was both time- and dose-dependent. After 24 h of treatment with SAHA, the early cell apoptotic rate increased from 3.25% to 21.02% (P = 0.041). The proportion of G0/G1 phase cells increased from 50.3% to 65.3% (P = 0.039), while that of S phase cells decreased from 34.9% to 20.6% (P = 0.049). After 48 h of treatment, hepatitis B surface antigen and hepatitis B e antigen content increased from 12.33 ± 0.62 to 25.42 ± 2.67 (P = 0.020) and 28.92 ± 1.24 to 50.48 ± 1.85 (P = 0.026), respectively. Furthermore, HBV DNA content increased from 4.54 ± 0.46 to 8.34 ± 0.59 (P = 0.029). CONCLUSION: SAHA inhibits HepG2.2.15 cell proliferation, promotes apoptosis, and stimulates HBV replication. In combination with anti-HBV drugs, SAHA may potentially be used cautiously for treatment of hepatocellular carcinoma.

HBcAg-specific CD8~+T Cells Inhibit HBV Replication in vitro / 医学研究杂志

Objective To investigate the effects of HBcAg-specific CD8+T cells on inhibiting HBV replication in vitro,and to search the cytokine of noncytolytic mechanisms in viral clearance. Methods By the method of coculture of HepG2.2.15 cell (target cells) with HLA-A2 matched HBcAg-specific CD8+T cell clone (effector cells) at E:T ratios of 1:50,and monitoring HBV production (HBsAg,HBeAg,and HBV-DNA)in coculture supernatants at 24h,48h and 72h,the percentage of decrease in HBV replication level was observed. Furthermore,blocking experiment with neutralizing mAbs to IFN-? was performed to evaluate the effect of this cytokine. Results CD8+T clone produced high levels of IFN-?following coculture with 2.2.15 cells. HBsAg,HBeAg and HBV-DNA in coculture supernatants were significantly reduced,and the greatest effect was observed at 72h by 54.55%,50.36% and 74.55%,respectively. The reduction of HBV DNA was decreased followed by using neutralizing mAbs to IFN-?. The maximum activity of cytotoxicity of target cells was at 24h by 15.66%. Conclusion ①HBV-specific CD8+T cells inhibit HBV replication by cytolytic and noncytolytic mechanisms.②The effect of noncytolytic mechanisms is mainly mediated by IFN-?.

Mycophenolate acid inhibits hepatitis B virus replication in HepG2.2.15 cells / 中国病理生理杂志

AIM: To investigate the effect of mycophenolate acid(MPA) on hepatitis B virus(HBV) replication in vitro.METHODS: In the presence or absence of guanosine,the HepG2.2.15 cells were treated with different concentrations of MPA(1-20 mg/L) for 4 days.Hepatitis B surface antigen(HBsAg) and hepatitis Be antigen(HBeAg) in supernatant were detected by ELISA.Intracellular HBV core mRNA and HBV DNA were analyzed by reverse transcription-polymerase chain reaction(RT-PCR) and slot blot hybridization,respectively.RESULTS: MPA suppressed the expression of HBsAg and HBeAg,and inhibited the replication of HBV DNA.The effect of MPA on HBV replication was reversed by addition of exogenous guanosine.CONCLUSION: MPA suppresses the expression of HBsAg,HBeAg and replication of HBV DNA in HepG2.2.15 cells.Reducing the synthesis of guanosine nucleotides may be involved in the mechanism of the inhibitory activity of MPA on HBV replication.

Association of Hepatitis B virus infection and the expression of Toll-like receptors 2 and 4 in HepG2 cells / 中华传染病杂志

Objective In order to explore the roles of TLR2 and TLR4 in the hepatocyte dam- age caused hy hepatitis B virus infection,and to find whether LPS can affect the damage of hepato- cytes pre-and pos-HBV infection,we detected the changes of TLR2 and TLR4 expressions in hu- man hepatocyte lines HepG2 cells and 2.2.15 cells.Methods HepG2 ceils are most similar to normal human hepatocytes and 2.2.15 ceils are HepG2 cells infected with HBV.We selected these two cell lines to study the differences of TLR2 and TLR4 expression between HepG2 cells before and after HBV infection.In this research,both HepG2 and 2.2.15 cells were stimulated with 0?g/ml, 1?g/ml,10?g/ml,100?g/ml,1 mg/ml and 10 mg/ml LPS.Then the expression of protein of TLR2 and TLR4 were examined by immuno-histochemistry(IHC).The cnRNA of HepG2 and 2.2.15 ceils stimulated with 0?g/ml and 10 mg/ml LPS were examined by reversal transcription-pol- ymerase chain reaction(RT-PCR).Thereafter,the apoptosis of HepG2 and HepG2.2.15 cells were examined by flow cytometry(FC),and the expressions of HBsAg and HBeAg of HepG2.2.15 cells tested with Abbott kits.Results IHC and RT-PCR analysis revealed that TLR2 and TLR4 expres- sions could he detected in both HepG2 and 2.2.15 cells.Moreover,without immune activation, TLR2 and TLR4 expressions were higher in the presence of higher concentrations of LPS.FC analy sis revealed that no apoptosis detected in HepG2 ceils stimulated with LPS in this research,but apop- tosis could be detected in 2.2.15 cells when treated with the same factors.Furthermore,the apoptosis ratios increased with the increase of LPS concentrations.When concentrations of LPS were 1?g/ml, 10?g/ml,100?g/ml,1 mg/ml and 10 mg/ml,the apoptosis ratios were 1.94%,3.03%,3.50%, 3.72%,5.30%,respectively.Abbott analysis revealed that expressions of HBsAg and HBeAg of 2.2.15 cells stimulated with LPS were lower than those not stimulated with LPS.Conclusion HBV can affect the expressions of TLR2 and TLR4 in HepG2 cell lines.LPS can lead 2.2.15 cells to apop- tosis but not HepG2 cells.Although LPS cannot damage normal hepatocytes,it might aggravate hep- atocytes damage when their microenvironment was changed by HBV infection.

Inhibitory effect of the serum containing Compound Liuyuexue on HBsAg and HBeAg in the HepG2.2.15 cells / 中成药

AIM:To study the inhibitory effect of Compound Liuyuexue(Tarphochlamys affinis(Giff) Bremekhu,Herba Hedyotis,Raidx Gardeniae,etc.)(CLYX) on HBV in vitro.METHODS:The serum containing CLYX was added to cultured HepG2.2.15 cells,and HepG2.2.15 cells were cultured in medium containing the serum with CLYX for 72 h and 144 h.The culture media were collected for determining the levels of HBsAg and HBeAg by ELISA.RESULTS:The serum containing CLYX could markedly inhibit HBsAg and HBeAg expressions in the HepG2.2.15 cells(P