Efficacy and Renal Safety of Prophylactic Tenofovir Alafenamide for HBV-Infected Cancer Patients Undergoing Chemotherapy.

There are no data comparing the efficacy and safety of prophylactic entecavir (ETV), tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF) for HBV-infected cancer patients undergoing chemotherapy. This study aimed to compare the efficacy and renal safety of ETV, TDF and TAF in this setting. HBsAg-positive cancer patients treated with ETV (n = 582), TDF (n = 200) and TAF (n = 188) during chemotherapy were retrospectively enrolled. Antiviral efficacy and risk of renal events were evaluated. The rate of complete viral suppression at 1 year was 94.7%, 94.7% and 96.1% in ETV, TDF and TAF groups, respectively (p = 0.877). A significant proportion of patients developed renal dysfunction during chemotherapy. The incidences of acute kidney injury (AKI) and chronic kidney disease stage migration were comparable among the ETV, TDF and TAF groups. TAF was relatively safe in patients with predisposing factors of AKI, including hypoalbuminemia and cisplatin use. In patients who were switched from TDF to TAF during chemotherapy, the renal function remained stable and viral suppression was well maintained after switching. In conclusion, TAF had good renal safety and comparable efficacy with ETV and TDF for HBV-infected cancer patients receiving chemotherapy. Switching from TDF to TAF during chemotherapy is safe, without a loss of efficacy.

Effect of sofosbuvir-based DAAs on changes in lower-density lipoprotein in HCV patients: a systematic review and meta-analysis.

BACKGROUND: Previous studies reported worsened lipid profiles in patients infected with hepatitis C virus (HCV) during direct-acting antivirals (DAAs) treatment. This study aimed to investigate the effect of sofosbuvir (SOF)-based DAAs on changes in low-density lipoprotein (LDL) in HCV patients. METHODS: A systematic review of articles published before 31 May 2021 was conducted by searching MEDLINE, Cochrane Library, EMBASE, and CINAHL Plus. Eligible studies were those comparing SOF-based DAAs and non-SOF DAAs for HCV patients and providing numerical data for changes in LDL. Risk of Bias in Non-randomized Studies- of Interventions was used for assessing risk of bias, and meta-analysis was performed for changes in LDL. RESULTS: Six studies comprising 1248 patients were included, 848 patients treated with SOF-based DAAs and 400 patients with non-SOF DAAs vs. SOF-based DAAs group had significantly greater increases in LDL from baseline to week 4 than non-SOF DAAs group (P = 0.001). However, changes in LDL from baseline to the end of treatment (P = 0.060), to post-treatment week 12 (P = 0.263), and to post-treatment week 24 (P = 0.319) did not significantly differ between the two groups. Further comparison of SOF/ledipasvir with asunaprevir/daclatasvir revealed a similar trend in changes in LDL. CONCLUSIONS: For HCV patients, SOF-based DAA regimens were associated with rapid and significant increases in LDL during the initial 4 weeks of treatment, and the changes did not sustain after the end of treatment. Potential mechanism might be related to the phosphoramidate side chain of SOF.

Virological and immunological predictors of long term outcomes of peginterferon alfa-2a therapy for HBeAg-negative chronic hepatitis B.

BACKGROUND/PURPOSE: Predictors of long-term outcomes of peginterferon (PegIFN) therapy for patients with chronic hepatitis B (CHB) remain to be explored. This study aimed to evaluate the predictive value of virological and immunological biomarkers and outcomes of PegIFN for CHB. METHODS: 57 HBeAg-negative CHB patients receiving 48 weeks of PegIFN therapy were prospectively followed for a median period of 5.3 years after the end of treatment (EOT). Serum CXCL9 and IP-10 levels were measured. Flow cytometry analysis for T cell subsets was performed in 23 patients. Factors associated with long-term outcomes were analyzed. RESULTS: The cumulative incidences of virological relapse, clinical relapse and HBsAg loss at year 7 were 18.1%, 0%, 31.6%, respectively, in patients with sustained off-treatment virological response (SVR), and 100%, 67.4%, 6.7%, respectively, in patients without SVR. By multivariate analysis, baseline CXCL9 > 80 pg/mL (hazard ratio (HR) = 0.418, p = 0.018) and on-treatment HBsAg declines were associated with a lower risk of virological relapse. Non-SVR was the only predictor of clinical relapse. CXCL9 >200 pg/mL (HR = 8.154, p = 0.038) and HBsAg <750 IU/mL (HR = 10.507, p = 0.036) were baseline predictors of HBsAg loss, while HBsAg decline >1 log at EOT (HR = 23.296, p = 0.005) was the on-treatment predictor of HBsAg loss. In subgroup patients with available PBMC, populations of T cell subsets correlated with virological and clinical relapses in univariate analysis. CONCLUSION: Baseline serum CXCL9 and HBsAg levels could predict HBsAg loss after PegIFN therapy for HBeAg-negative CHB. Combining virological and immunological biomarkers could predict long-term outcomes of PegIFN therapy for HBeAg-negative CHB.

Incidence and Predictors of HBsAg Loss After Peginterferon Therapy in HBeAg-Negative Chronic Hepatitis B: A Multicenter, Long-term Follow-up Study.

Background: The long-term incidence and factors associated with hepatitis B surface antigen (HBsAg) loss in hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB) patients receiving peginterferon is rarely reported. Methods: From 2004 to 2016, 233 HBeAg-negative CHB patients who completed 48 weeks of peginterferon treatment from 3 medical centers in Taiwan were retrospectively enrolled. Results: During a median follow-up of 7.4 years, 27 cases achieved HBsAg loss. The cumulative incidences of HBsAg loss and HBsAg seroconversion at 3, 5, 10 years after peginterferon treatment were 4.7%, 9.4%, 14.2%, and 3.5%, 6.4%, 12.5%, respectively, in overall patients, and 15.9%, 29.1%, 37.3%, and 13.1%, 19%, 30.6%, respectively, in patients achieving sustained off-treatment virological response (SVR). By multivariate analysis, age (<35 years; hazard ratio [HR] = 3.742, P = .007), baseline HBsAg levels (<1250 IU/mL; HR = 4.849, P = .002), HBsAg decline at week 24 (≥1 log; HR = 5.660, P = .002), and achieving SVR (HR = 8.546, P = .006) were predictors of HBsAg loss. After achieving SVR, HBsAg loss rates were higher than 30% in 5 years among patients with either younger age or lower HBsAg at baseline. Conclusions: HBsAg loss rate continues to increase after peginterferon treatment in HBeAg-negative CHB patients with SVR. Age, baseline HBsAg levels, on-treatment HBsAg decline, and achieving SVR are factors associated with long-term HBsAg loss.

Risk of renal events during tenofovir disoproxil fumarate and entecavir antiviral prophylaxis in HBsAg-positive cancer patients undergoing chemotherapy.

The risk of renal events in HBsAg-positive cancer patients receiving tenofovir disoproxil fumarate (TDF) or entecavir (ETV) antiviral prophylaxis during chemotherapy has not been evaluated. This study aimed to evaluate the renal safety of TDF and ETV during chemotherapy. Consecutive, 219 HBsAg-positive cancer patients treated with TDF (n = 106) or ETV (n = 113) for antiviral prophylaxis during chemotherapy with baseline serum creatinine (SCr) <1.2 mg/dL were retrospectively enrolled. Serial SCr levels and estimated glomerular filtration rate (eGFR) were monitored. The incidence of acute kidney injury (AKI) during antiviral prophylaxis was 33% and 38.9% in TDF and ETV groups, respectively (P = 0.441), while the incidence of sustained kidney injury was 11.3% and 11.5%, respectively (P = 1.000). By multivariate analysis, diuretics use (hazard ratio (HR) = 2.011, P = 0.042) and serum albumin levels (HR = 0.441, P = 0.001) were independent predictors of AKI; serum albumin levels (HR = 0.252, P = 0.002) was the only factor associated with sustained kidney injury; age (HR = 2.752, P < 0.001), baseline SCr levels (HR = 3.386, P < 0.001), and serum albumin levels (HR = 0.437, P = 0.001) were factors associated with a new eGFR <60 mL/min. 34.9% of patients in TDF group and 35.4% in ETV group had deteriorated chronic kidney disease (CKD) stage at the end of follow-up, respectively. There were no significant differences in the risk of renal events or CKD stage migration between TDF and ETV groups. Renal events may develop in about one-third of HBsAg-positive cancer patients undergoing chemotherapy. The risk of renal function impairment was comparable between patients treated with TDF and ETV antiviral prophylaxis.

Same-day Versus Split-dose Bowel Preparation Before Colonoscopy: A Meta-analysis.

BACKGROUND: Split-dose regimens (SpDs) were recommended as a first choice for bowel preparation, whereas same-day regimens (SaDs) were recommended as an alternative; however, randomized trials compared them with mixed results. The meta-analysis was aimed at clarifying efficacy level between the 2 regimens. MATERIALS AND METHODS: We used MEDLINE/PubMed, EMBASE, Scopus, CINAHL, Cochrane Library, and Web of Science to identify randomized trials published from 1990 to 2016, comparing SaDs to SpDs in adults. The pooled odds ratios (ORs) were calculated for preparation quality, cecal intubation rate (CIR), adenoma detection rate (ADR), and any other adverse effects. RESULTS: Fourteen trials were included. The proportion of individuals receiving SaDs and SpDs with adequate preparation in the pooled analysis were 79.4% and 81.7%, respectively, with no significant difference [OR=0.92; 95% confidence interval (CI), 0.62-1.36] in 11 trials. Subgroup analysis revealed that the odds of adequate preparation for SaDs with bisacodyl were 2.45 times that for SpDs without bisacodyl (95% CI, 1.45-4.51, in favor of SaDs with bisacodyl). Subjects received SaDs experienced better sleep. CONCLUSIONS: SaDs were comparable with SpDs in terms of bowel cleanliness, CIR, and ADR, and could also outperform SpDs in preparation quality with bisacodyl. SaDs also offered better sleep the previous night than SpDs did, which suggests that SaDs might serve as a superior alternative to SpDs. The heterogenous regimens and measurements likely account for the low rates of optimal bowl preparations in both arms. Further studies are needed to validate these results and determine the optimal purgatives and dosages.

Oncogenic circuit constituted by Ser31-HBx and Akt increases risks of chronic hepatitis and hepatocellular carcinoma.

The X protein of hepatitis B virus (HBx) has been specifically implicated in the development of hepatocellular carcinoma (HCC). Clinical associations of HBx isoforms with chronic hepatitis and HCC have not been well studied. HBx has two roles in liver cells, namely pro-apoptotic and anti-apoptotic. In this report, we examined the role of Ser31-HBx in HCC and chronic hepatitis. Using the case-control study, we determined risks of chronic hepatitis and HCC conferred by hepatitis B virus (HBV) containing Ser31-HBx that was phosphorylated by Akt. Ser31-HBx isoforms conferred 3.23-fold risk of HCC in male and 3.36-fold risk in female. Ser31 isoforms were associated with 3.12-fold risk of chronic hepatitis and 3.43-fold risk of cirrhosis and also associated with higher HBV viral load and replication efficiency and lower rate of HBe loss. To determine the mechanism, we found that Ser31-HBx constituted an oncogenic circuit with Akt and cooperated with ras to transform NIH3T3 cells in contrast to non-Ser31-HBxs that did not transduce oncogenic signals. Our results give a clue to account for an underlying cause of HBx-mediated hepatocarcinogenesis. It appears that Ser31 phosphorylation of HBx by Akt plays an important role. The current study provides an example of association of HBV genome variations with risks of HCC and chronic hepatitis.

The telomere-binding protein TRF2 is required for metronomic therapeutic effects of gemcitabine and capecitabine.

Gemcitabine and capecitabine are two effective anticancer agents against solid tumors. The pharmacological mechanisms have been known as incorporation into DNA and thereby inhibition of DNA synthesis. When used as metronomic chemotherapy, they may inhibit angiogenesis and induce immunity. In our previous study, we showed that low-dose gemcitabine caused telomere shortening by stabilizing TRF2 that was required for XPF-dependent telomere loss. In this report, we established a SKOV3.ip1 ascites cell model. Tumor-bearing mice were treated with low-dose gemcitabine (GEM) or capecitabine (CAP). Both GEM and CAP caused telomere shortening and increased expression of TRF2 with improved ascites in nude mice and decreased in vitro clonogenic activity. TRF2 knockdown altered telomeres to a shortened but new status that may evade XPF-dependent telomere loss and conferred resistance of SKOV3.ip1 ascites cells to low-dose GEM and CAP. Our study provides a new mechanism of metronomic chemotherapy i.e. TRF2 is required for metronomic therapeutic effects of gemcitabine and capecitabine.

Integrative functional genomics of hepatitis C virus infection identifies host dependencies in complete viral replication cycle.

Recent functional genomics studies including genome-wide small interfering RNA (siRNA) screens demonstrated that hepatitis C virus (HCV) exploits an extensive network of host factors for productive infection and propagation. How these co-opted host functions interact with various steps of HCV replication cycle and exert pro- or antiviral effects on HCV infection remains largely undefined. Here we present an unbiased and systematic strategy to functionally interrogate HCV host dependencies uncovered from our previous infectious HCV (HCVcc) siRNA screen. Applying functional genomics approaches and various in vitro HCV model systems, including HCV pseudoparticles (HCVpp), single-cycle infectious particles (HCVsc), subgenomic replicons, and HCV cell culture systems (HCVcc), we identified and characterized novel host factors or pathways required for each individual step of the HCV replication cycle. Particularly, we uncovered multiple HCV entry factors, including E-cadherin, choline kinase α, NADPH oxidase CYBA, Rho GTPase RAC1 and SMAD family member 6. We also demonstrated that guanine nucleotide binding protein GNB2L1, E2 ubiquitin-conjugating enzyme UBE2J1, and 39 other host factors are required for HCV RNA replication, while the deubiquitinating enzyme USP11 and multiple other cellular genes are specifically involved in HCV IRES-mediated translation. Families of antiviral factors that target HCV replication or translation were also identified. In addition, various virologic assays validated that 66 host factors are involved in HCV assembly or secretion. These genes included insulin-degrading enzyme (IDE), a proviral factor, and N-Myc down regulated Gene 1 (NDRG1), an antiviral factor. Bioinformatics meta-analyses of our results integrated with literature mining of previously published HCV host factors allows the construction of an extensive roadmap of cellular networks and pathways involved in the complete HCV replication cycle. This comprehensive study of HCV host dependencies yields novel insights into viral infection, pathogenesis and potential therapeutic targets.

Helicobacter pylori-induced chronic inflammation causes telomere shortening of gastric mucosa by promoting PARP-1-mediated non-homologous end joining of DNA.

Helicobacter pylori infection leads to chronic gastritis and increased risk of gastric cancer. The mechanism involves chronic inflammation. We aimed to determine the mechanism by which H. pylori infection causes telomere shortening in inflammatory gastric mucosa. Gastric biopsy specimens were obtained from 20 patients with chronic gastritis or peptic ulcer caused by H. pylori infection. The specimens showed increased NF-κB and superoxide dismutase activities and elevated expressions of PARP-1 and γ-H2AX, all of which returned to normal levels after anti-H. pylori treatment, suggesting that oxidative DNA damage and PARP-1 overexpression might cause telomere shortening. In this report, we adopted DNA end joining assay and showed that H. pylori-infected gastric mucosa had increased alternative NHEJ (non-homologous end joining), implicating that telomere shortening was caused by inflammation-mediated overproduction of reactive oxygen species and PARP-1, leading to telomere shortening.

Anti-hepatitis C virus seropositivity is not associated with metabolic syndrome irrespective of age, gender and fibrosis.

Although many studies have tried to clarify the association between hepatitis C virus (HCV) infection and metabolic syndrome, few studies have comprehensively assessed their relationship stratified by different demographic characteristics. We aimed to investigate the correlation between metabolic syndrome and anti-HCV seropositivity in Taiwan. This study enrolled consecutive subjects who had received health check-up services at Taipei Veterans General Hospital from 2002 to 2009. Metabolic syndrome was diagnosed according to the criteria defined by the International Diabetes Federation Task Force on Epidemiology and Prevention. Among the 30616 subjects enrolled in this study, the prevalence of positive anti-HCV serology was 2.7%, and 28.8% were diagnosed with metabolic syndrome. By multivariate analysis, metabolic syndrome was associated with higher body mass index, older age, male sex, a higher level of alanine aminotransferase, gamma-glutamyltransferase, platelet count and the presence of fatty liver whereas anti-HCV seropositivity was not an independent variable for metabolic syndrome. Further stratifying the subjects by age and sex, and there was still no significant difference in HCV status between those with and without metabolic syndrome. Moreover, the stage of liver fibrosis represented by aspartate aminotransferase to platelet ratio index was also not correlated with metabolic syndrome in the subjects with anti-HCV seropositivity. In conclusion, although subjects with anti-HCV seropositivity had higher fasting glucose levels and lower cholesterol and triglyceride levels compared to those with negative anti-HCV test, anti-HCV seropositivity was not associated with metabolic syndrome based on the current diagnostic criteria irrespective of age, gender and the stage of hepatic fibrosis.

Novel cell-based hepatitis C virus infection assay for quantitative high-throughput screening of anti-hepatitis C virus compounds.

Therapy for hepatitis C virus (HCV) infection has advanced with the recent approval of direct-acting antivirals in combination with peginterferon and ribavirin. New antivirals with novel targets are still needed to further improve the treatment of hepatitis C. Previously reported screening methods for HCV inhibitors either are limited to a virus-specific function or apply a screening method at a single dose, which usually leads to high false-positive or -negative rates. We developed a quantitative high-throughput screening (qHTS) assay platform with a cell-based HCV infection system. This highly sensitive assay can be miniaturized to a 1,536-well format for screening of large chemical libraries. All candidates are screened over a 7-concentration dose range to give EC50s (compound concentrations at 50% efficacy) and dose-response curves. Using this assay format, we screened a library of pharmacologically active compounds (LOPAC). Based on the profile of dose-dependent curves of HCV inhibition and cytotoxicity, 22 compounds with adequate curves and EC50s of <10 µM were selected for validation. In two additional independent assays, 17 of them demonstrated specific inhibition of HCV infection. Ten potential candidates with efficacies of >70% and CC50s (compound concentrations at 50% cytotoxicity) of <30 µM from these validated hits were characterized for their target stages in the HCV replication cycle. In this screen, we identified both known and novel hits with diverse structural and functional features targeting various stages of the HCV replication cycle. The pilot screen demonstrates that this assay system is highly robust and effective in identifying novel HCV inhibitors and that it can be readily applied to large-scale screening of small-molecule libraries.

Akt1 is involved in HCV release by promoting endoplasmic reticulum-to-endosome transition of infectious virions.

AIMS: Hepatitis C virus (HCV) relies on the viral and host factors to complete its life cycle. It has evolved to profit from Akt activation at some stage in its life cycle through various mechanisms, notably by activating lipogenesis, which is crucial for infectious virions production. MATERIALS AND METHODS: By employing an Akt-specific inhibitor, the impact of Akt on intracellular and extracellular infectivity was investigated. To ascertain the role of Akt in the HCV life cycle, the two-part cell culture-derived HCV infection protocol utilizing Akt1 small interfering RNAs (siRNAs) was implemented. The impact of Akt1 on intracellular HCV transition was determined using membrane flotation assay and proximity ligation assay coupled with Anti-Rab7 immunoprecipitation and immunofluorescence. KEY FINDINGS: Akt1 silencing reduced infectious virions release to a degree comparable to that of ApoE, a host component involved in the HCV assembly and release, suggesting Akt1 was critical in the late stage of the HCV life cycle. Extracellular infectivity of HCV was inhibited by brefeldin A, and the inhibitory effect was augmented by Akt1 silencing and partially restored by ectopic Akt1 expression. Immunofluorescence revealed that Akt1 inhibition suppressed the interaction between HCV core protein and lipid droplet. Akt1 silencing impeded the transition of HCV from the endoplasmic reticulum to the endosome and hence inhibited the secretion of HCV infectious virions from the late endosome. SIGNIFICANCE: Our study demonstrates that Akt1 has an impact on the lipogenesis pathway and plays a critical role in the assembly and secretion of infectious HCV.

Ser235 phosphorylation of hepatitis C virus NS5A is required for NS5A dimerization and drug resistance.

Hepatitis C virus (HCV) infection is recognized as a major causative agent of chronic hepatitis, cirrhosis, and hepatocellular carcinoma. HCV non-structural protein 5A (NS5A) is a dimeric phosphoprotein with a hyperphosphorylated form to act as a switch that regulates HCV replication and assembly. NS5A inhibitors have been utilized as the scaffold for combination therapy of direct-acting antiviral agents (DAA). However, the mode of action of NS5A inhibitors is still unclear due to the lack of mechanistic detail regarding NS5A phosphorylation and dimerization in the HCV life cycle. It has been demonstrated that phosphorylation of NS5A at Ser235 is essential for RNA replication of the JFH1 strain. In this report, we found that NS5A phosphomimetic Ser235 substitution (Ser-to-Asp mutation) formed a dimer that was resistant to disruption by NS5A inhibitors as was the NS5A resistance-associated substitution Y93H. Phosphorylation of NS5A at Ser235 residue was required for the interaction of two NS5A-WT molecules in JFH1-based cell culture system but not absolutely required for dimerization of the NS5A-Y93H mutant. Interestingly, HCV nonstructural proteins from the subgenomic replicon NS3-5A was required for NS5A-WT dimerization but not required for NS5A-Y93H dimerization. Our data suggest that spontaneous Ser235 phosphorylation of NS5A and ensuing dimerization account for resistance of the JFH1/NS5A-Y93H mutant to NS5A inhibitors.

Ser38-His93-Asn91 triad confers resistance of JFH1 HCV NS5A-Y93H variant to NS5A inhibitors.

HCV NS5A is a dimeric phosphoprotein involved in HCV replication. NS5A inhibitors are among direct-acting antivirals (DAA) for HCV therapy. The Y93H mutant of NS5A is resistant to NS5A inhibitors, but the precise mechanism remains unclear. In this report, we proposed a Ser38-His93-Asn91 triad to dissect the mechanism. Using pymol 1.3 software, the homology structure of JFH1 NS5A was determined based on the dimer structure of genotype 1b extracted from the database Protein DataBank (www.ebi.ac.uk/pdbsum) with codes 1ZH1 and 3FQM/3FQQ. FLAG-NS5A-WT failed to form dimer in the absence of nonstructural proteins from subgenomic replicon (NS3-5A); however, FLAG-NS5A-Y93H was able to form dimer without the aid of NS3-5A. The Ser38-His93-Asn91 triad in the dimer of the Y93H variant predicts a structural crash of the cleft receiving the NS5A inhibitor daclatasvir. The dimerization assay revealed that the existence of JFH1-NS5A-1ZH1 and -3FQM homology dimers depended on each other for existence and that both NS5A-WT 1ZH1 and 3FQM dimers cooperated to facilitate RNA replication. However, NS5A-Y93H 1ZH1 alone could form dimer and conduct RNA replication in the absence of the 3FQM structure. In conclusion, this study provides novel insight into the functional significance of the Ser38-His93-Asn91 triad in resistance of the Y93H variant to NS5A inhibitors.

Honokiol thwarts gastric tumor growth and peritoneal dissemination by inhibiting Tpl2 in an orthotopic model.

Honokiol is known to suppress the growth of cancer cells; however, to date, its antiperitoneal dissemination effects have not been studied in an orthotopic mouse model. In the present study, we evaluated the antiperitoneal dissemination potential of Honokiol in an orthotopic mouse model and assessed associations with tumor growth factor-ß1 (TGFß1) and cells stimulated by a carcinogen, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Our results demonstrate that tumor growth, peritoneal dissemination and peritoneum or organ metastasis of orthotopically implanted MKN45 cells were significantly decreased in Honokiol-treated mice and that endoplasmic reticulum (ER) stress was induced. Honokiol-treated tumors showed increased epithelial signatures such as E-cadherin, cytokeratin-18 and ER stress marker. In contrast, decreased expression of vimentin, Snail and tumor progression locus 2 (Tpl2) was also noted. TGFß1 and MNNG-induced downregulation of E-cadherin and upregulation of Tpl2 were abrogated by Honokiol treatment. The effect of Tpl2 inhibition in cancer cells or endothelial cells was associated with inactivation of CCAAT/enhancer binding protein B, nuclear factor kappa-light-chain-enhancer of activated B cell and activator protein-1 and suppression of vascular endothelial growth factor. Inhibition of Tpl2 in gastric cancer cells by small interfering RNA or pharmacological inhibitor was found to effectively reduce growth ability and vessel density in vivo. Honokiol-induced reversal of epithelial-to-mesenchymal transition (EMT) and ER stress-induced apoptosis via Tp12 may involve the paralleling processes. Taken together, our results suggest that the therapeutic inhibition of Tpl2 by Honokiol thwarts both gastric tumor growth and peritoneal dissemination by inducing ER stress and inhibiting EMT.

Phosphorylation accelerates geldanamycin-induced Akt degradation.

Hsp90 (Heat shock protein-90) is a cellular buffer against erroneous gene products and also plays an essential role in facilitating proper folding, maturation, and activity of its client proteins. The phosphatidylinositol-3 kinase (PI-3K)-Akt pathway transduces a survival signal involved in tumor development. The kinase activity of Akt depends on its association with Hsp90. Hsp90 inhibition causes Akt degradation, but the mechanism remains unclear. Several reports showed that the Hsp90 inhibitor geldanamycin (GA) induces Thr308 and Ser473 phosphorylations of Akt, however, it is still unknown about the significance of GA-induced Akt activation in degradation of the kinase. We treated Hela cells with GA to observe Akt degradation and found that LY294002 delayed Akt degradation. Mutation of Thr308 or Ser473 also caused delayed Akt ubiquitination and degradation. Inhibition of Akt dephosphorylation enhanced GA-mediated Akt degradation. In this report, we show that GA-mediated transient activation of Akt accelerates its association with the E3 ligase CHIP (C-terminal Hsp70-interacting protein)-mediated ubiquitination and subsequent proteasome degradation.

Amiodarone inhibits the entry and assembly steps of hepatitis C virus life cycle.

HCV (hepatitis C virus) infection affects an estimated 180 million people in the world's population. Adverse effects occur frequently with current standard treatment of interferon and ribavirin, while resistance of new direct anti-viral agents, NS3 protease inhibitors, is a major concern because of their single anti-HCV mechanism against the viral factor. New anti-viral agents are needed to resolve the problems. Amiodarone, an anti-arrhythmic drug, has recently been shown to inhibit HCV infection in vitro. The detailed mechanism has yet to be clarified. The aim of the present study was to elucidate the molecular mechanism of the inhibitory effect of amiodarone on HCV life cycle. The effect of amiodarone on HCV life cycle was investigated in Huh-7.5.1 cells with HCVcc (cell culture-derived HCV), HCVpp (HCV pseudoviral particles), sub-genomic replicons, IRES (internal ribosomal entry site)-mediated translation assay, and intracellular and extracellular infectivity assays. The administration of amiodarone appeared to inhibit HCV entry independent of genotypes, which was attributed to the down-regulation of CD81 receptor expression. The inhibitory effect of amiodarone also manifested in the HCV assembly step, via the suppression of MTP (microsomal triacylglycerol transfer protein) activity. Amiodarone revealed no effects on HCV replication and translation. With the host factor-targeting characteristics, amiodarone may be an attractive agent for the treatment of HCV infection.

Pro-apoptotic or anti-apoptotic property of X protein of hepatitis B virus is determined by phosphorylation at Ser31 by Akt.

The X protein of hepatitis B virus (HBx) has been specifically implicated in either pro-apoptotic or anti-apoptotic activity in an experimental system, but the underlying mechanism is yet uncertain. Activations of survival and proliferation signaling pathways appear to account partly for its anti-apoptotic property. Change in mitochondrial membrane potential may be responsible for its apoptotic property. In this study, we isolated two HBx isoforms from an HBV carrier, one of which contains Akt phosphorylation site at Ser31 and functions as an anti-apoptotic protein (designated HBx-S31). The other does not contain Akt phosphorylation site and functions as an apoptotic protein (designated HBx-L31). HBx-S31 can activate Akt, whereas HBx-L31 cannot; the former enhances tumor growth, whereas the latter suppresses tumorigenesis. Our study provides evidence that HBx plays dual roles, namely pro-apoptotic and anti-apoptotic, through different isoforms in which HBx with Ser31 transduces survival signal.

Multiple effects of Honokiol on the life cycle of hepatitis C virus.

BACKGROUND: Honokiol, a small active molecular compound extracted from magnolia, has recently been shown to inhibit hepatitis C virus (HCV) infection in vitro. AIMS: This study further characterized aspects of the HCV lifecycle affected by the antiviral functions of honokiol. METHODS: The influence of honokiol on HCV infection, entry, translation and replication was assessed in Huh-7.5.1 cells using cell culture-derived HCV (HCVcc), HCV pseudo-type (HCVpp) and sub-genomic replicons. RESULTS: Honokiol had strong antiviral effect against HCVcc infection at non-toxic concentrations. Combined with interferon-α, its inhibitory effect on HCVcc was more profound than that of ribavirin. Honokiol inhibited the cell entry of lentiviral particles pseudo-typed with glycoproteins from HCV genotypes 1a, 1b, and 2a, but not of the vesicular stomatitis virus. It had inefficient activity on HCV internal ribosome entry site (IRES)-translation at concentrations with significant anti-HCVcc effects. The expression levels of components of replication complex, NS3, NS5A and NS5B, were down-regulated by honokiol in a dose-dependent manner. It also inhibited HCV replication dose dependently in both genotypes 1b and 2a sub-genomic replicons. CONCLUSIONS: Honokiol inhibits HCV infection by targeting cell entry and replication and, only at a concentration >30 µM, IRES-mediated translation of HCV life cycle. Based on its high therapeutic index (LD(50) /EC(90)  = 5.4), honokiol may be a promising drug for the treatment of HCV infection.