Mf Sprinzl

Transfer of Hepatitis B Virus Genome by Adenovirus Vectors into Cultured Cells and Mice: Crossing the Species Barrier

ABSTRACT For the study of hepatitis B virus infection, no permissive cell line or small animal is available. Stably transfected cell lines and transgenic mice which contain hepadnavirus genomes produce virus, but—unlike in natural infection—from an integrated viral transcription template. To transfer hepadnavirus genomes across the species barrier, we developed adenovirus vectors in which 1.3-fold-overlength human and duck hepatitis B virus genomes were inserted. The adenovirus-mediated genome transfer efficiently initiated hepadnavirus replication from an extrachromosomal template in established cell lines, in primary hepatocytes from various species, and in the livers of mice. Following the transfer, hepatitis B virus proteins, genomic RNA, and all replicative DNA intermediates were detected. Detection of covalently closed circular DNA in hepatoma cell lines and in primary hepatocytes indicated that an intracellular replication cycle independent from the transferred linear viral genome was established. High-titer hepatitis B virions were released into the culture medium of hepatoma cells and the various primary hepatocytes. In addition, infectious virions were secreted into the sera of mice. In conclusion, adenovirus-mediated genome transfer initiated efficient hepatitis B virus replication in cultured liver cells and in the experimental animals from an extrachromosomal template. This will allow development of small-animal systems of hepatitis B virus infection and will facilitate study of pathogenicity of wild-type and mutant viruses as well as of virus-host interaction and new therapeutic approaches.

Sorafenib perpetuates cellular anticancer effector functions by modulating the crosstalk between macrophages and natural killer cells

Alternatively polarized macrophages (Mϕ) shape the microenvironment of hepatocellular carcinoma (HCC) and temper anticancer immune responses. We investigated if sorafenib alters the HCC microenvironment by restoring classical macrophage polarization and triggering tumor‐directed natural killer (NK) cell responses. In vivo experiments were conducted with sorafenib (25 mg/kg)‐treated C57BL/6 wildtype as well as hepatitis B virus (HBV) and lymphotoxin transgenic mice with and without HCC. Monocyte‐derived Mϕ or tumor‐associated macrophages (TAM) isolated from HCC tissue were treated with sorafenib (0.07‐5.0 μg/mL) and cocultured with autologous NK cells. Mϕ and NK cell activation was analyzed by flow cytometry and killing assays, respectively. Cytokine and growth factor release was measured by enzyme‐linked immunosorbent assay. Short‐term administration of sorafenib triggered activation of hepatic NK cells in wildtype and tumor‐bearing mice. In vitro, sorafenib sensitized Mϕ to lipopolysaccharide, reverted alternative Mϕ polarization and enhanced IL12 secretion (P = 0.0133). NK cells activated by sorafenib‐treated Mϕ showed increased degranulation (15.3 ± 0.2% versus 32.0 ± 0.9%, P < 0.0001) and interferon‐gamma (IFN‐γ) secretion (2.1 ± 0.2% versus 8.0 ± 0.2%, P < 0.0001) upon target cell contact. Sorafenib‐triggered NK cell activation was verified by coculture experiments using TAM. Sorafenib‐treated Mϕ increased cytolytic NK cell function against K562, Raji, and HepG2 target cells in a dose‐dependent manner. Neutralization of interleukin (IL)12 or IL18 as well as inhibition of the nuclear factor kappa B (NF‐κB) pathway reversed NK cell activation in Mϕ/NK cocultures. Conclusion: Sorafenib triggers proinflammatory activity of TAM and subsequently induces antitumor NK cell responses in a cytokine‐ and NF‐κB‐dependent fashion. This observation is relevant for HCC therapy, as sorafenib is a compound in clinical use that reverts alternative polarization of TAM in HCC. (HEPATOLOGY 2013;57:2358–2368)

Efficacy of an escalating dose regimen of pegylated interferon α-2a plus ribavirin in the early phase of HCV reinfection after liver transplantation

We evaluated the safety and efficacy of an escalating dose regimen of pegylated interferon α‐2a (PEG‐IFNα‐2a) and ribavirin in the early phase of recurrent hepatitis C after orthotopic liver transplantation (OLT). In this prospective study, 26 patients transplanted for hepatitis C virus cirrhosis with recurrent hepatitis C were treated 3.4 ± 3.6 months after OLT and compared with an untreated historical control. PEG‐IFNα‐2a was initiated as monotherapy, following stepwise dose escalation up to 180 μg/week and the addition of ribavirin up to 1200 mg/day or maximally tolerated doses for 48 weeks. In the intent‐to‐treat analysis, 38% showed an early virological response (EVR), 35% an end of treatment response (ETR) and 19% a sustained virological response (SVR). SVR was associated with EVR (P = 0.0001) and cumulative PEG‐IFNα‐2a dose (P = 0.04). There was no significant histological improvement compared with untreated patients. There were no treatment‐related serious adverse events. Adverse events included leucopenia (77%) and thrombocytopenia (46%). Three patients discontinued therapy due to side effects, fourteen were nonresponders and four relapsers. Treatment with PEG‐IFNα‐2a and ribavirin in the acute phase of post‐transplant recurrent hepatitis C yielded an EVR of 38% and an SVR of 19%. The combination was safe and well tolerated.

Ablation of c-FLIP in hepatocytes enhances death-receptor mediated apoptosis and toxic liver injury in vivo.

BACKGROUND & AIMS Apoptosis is crucially involved in acute and chronic liver injury, including viral, cholestatic, toxic, and metabolic liver disease. Additionally, dysregulation of apoptosis signaling pathways has been implicated in hepatocarcinogenesis. The most prominent members of the apoptosis-mediating tumor necrosis factor receptor superfamily are the TNF-R1 (CD120a) and the CD95 (Apo-1/Fas) receptor. Although extensively studied, the intracellular signaling events in hepatocytes are only incompletely understood. METHODS To examine the role of the caspase-8 homolog cellular FLICE-inhibitory protein (c-FLIP) in liver injury, we generated mice with hepatocyte specific deletion of c-FLIP. Three models of acute liver injury were employed: the agonistic anti-CD95 antibody Jo2, d-galactosamine and LPS (GalN/LPS), and concanavalin A. RESULTS Conditional ablation of c-FLIP in hepatocytes augmented liver injury and cell death in all three models of liver injury. CD95- and GalN/LPS-induced liver injury was ameliorated by a pancaspase inhibitor, while ConA-induced injury was unaffected by caspase inhibition. Augmented activation of the MAPK JNK was observed in parallel to liver injury in c-FLIP knockout mice in all injury models; however, inhibition of JNK only affected TNF- and ConA-mediated injury. CONCLUSIONS In summary, c-FLIP is a central regulator of cell death in hepatocytes, involving increased activation of caspases and the MAPK JNK.

Gemcitabine in combination with EGF-Receptor antibody (Cetuximab) as a treatment of cholangiocarcinoma: a case report

BackgroundExtensive disease of cholangiocarcinoma (CC) determines the overall outcome and limits curative resection. Despite chemotherapy, which has been introduced to improve the outcome of biliary tract malignancies, the benefit in survival is still marginal.Case presentationWe report a 69-year-old patient with non-resectable CC showing hepatic metastasis and peritoneal carcinomatosis. Diagnosis was based on computed tomography, mini-laparoscopy and bioptic specimens. Histology revealed an adenocarcinoma of the biliary tract with expression of epithelial growth factor receptor. After informed consent the patient received experimental gemcitabine (1000 mg/m2) every other week and cetuximab (250 mg/m2) weekly for palliative chemotherapy. During the reported follow up (since time of first presentation) 20 cycles of chemotherapy were administered. Relevant chemotherapy-related toxicity was limited on gemcitabine-associated side effects. Predominantly, haematological toxicity (CTC, grade 3) and neutropenic fever (CTC, grade 3) promoted by catheter-related sepsis were observed. Cetuximab caused only mild skin toxicity (CTC, grade 1).Chemotherapy led to a partial response (> 30% reduction, according to RECIST) of the target lesions and disappearance of the peritoneal carcinomatosis as shown by computed tomography. Partial response occurred after 17 weeks of treatment and remained stable during the entire course of chemotherapy for 9.7 months. In parallel, Ca 19-9 serum levels, which were elevated 5-fold at time of diagnosis, returned to normal after 16 weeks of treatment. The performance status stabilized and intravenous alimentation could be discontinued.ConclusionOur experience from one patient with CC suggests, that a combination of cytotoxic chemotherapy together with cetuximab may show promising efficacy in respect to survival and quality of life. Therefore cetuximab, as a component of palliative chemotherapy in biliary tract cancer, needs further evaluation in prospective randomized trials.

T Cells Engineered to Express a T-Cell Receptor Specific for Glypican-3 to Recognize and Kill Hepatoma Cells In Vitro and in Mice

BACKGROUND & AIMS Cancer therapies are being developed based on our ability to direct T cells against tumor antigens. Glypican-3 (GPC3) is expressed by 75% of all hepatocellular carcinomas (HCC), but not in healthy liver tissue or other organs. We aimed to generate T cells with GPC3-specific receptors that recognize HCC and used them to eliminate GPC3-expressing xenograft tumors grown from human HCC cells in mice. METHODS We used mass spectrometry to obtain a comprehensive peptidome from GPC3-expressing hepatoma cells after immune-affinity purification of human leukocyte antigen (HLA)-A2 and bioinformatics to identify immunodominant peptides. To circumvent GPC3 tolerance resulting from fetal expression, dendritic cells from HLA-A2-negative donors were cotransfected with GPC3 and HLA-A2 RNA to stimulate and expand antigen-specific T cells. RESULTS Peptide GPC3367 was identified as a predominant peptide on HLA-A2. We used A2-GPC3367 multimers to detect, select for, and clone GPC3-specific T cells. These clones bound the A2-GPC3367 multimer and secreted interferon-γ when cultured with GPC3367, but not with control peptide-loaded cells. By genomic sequencing of these T-cell clones, we identified a gene encoding a dominant T-cell receptor. The gene was cloned and the sequence was codon optimized and expressed from a retroviral vector. Primary CD8(+) T cells that expressed the transgenic T-cell receptor specifically bound GPC3367 on HLA-A2. These T cells killed GPC3-expressing hepatoma cells in culture and slowed growth of HCC xenograft tumors in mice. CONCLUSIONS We identified a GPC3367-specific T-cell receptor. Expression of this receptor by T cells allows them to recognize and kill GPC3-positive hepatoma cells. This finding could be used to advance development of adoptive T-cell therapy for HCC.

Metabolic syndrome and its association with fatty liver disease after orthotopic liver transplantation

The metabolic syndrome (MetS) might contribute to morbidity after orthotopic liver transplantation (OLT). For this reason, we searched for MetS‐associated risk factors and analyzed the link with nonalcoholic fatty liver disease (NAFLD) in OLT recipients. De novo MetS affected 32.9% of our cohort (n = 170) within 2 years after OLT. Multivariate analysis identified glycosylated hemoglobin (HbA1c) levels ≥5% [odds ratio (OR) = 3.5; 95% confidence interval (CI) = 1.56–8.13, P = 0.003], diabetes mellitus (OR = 4.31, CI = 1.69–10.99, P = 0.002), and arterial hypertension (OR = 4.59, CI = 1.46–14.49, P = 0.009) as independent risk factors for de novo MetS. MetS incidence correlated with steroid dosage after OLT (5.2 ± 2.4 mg/day vs. 7.1 ± 4.7 mg/day, P = 0.014), and was linked to NAFLD (P = 0.001) via obesity (OR = 4.67, CI = 1.55–14.1, P = 0.006) and dyslipidemia (OR = 4.23, CI = 1.35–13.3, P = 0.013) post‐OLT. In conclusion, we were able to identify low threshold HbA1c as a novel risk factor for MetS after OLT and described a link of MetS with NAFLD in transplant organs. This study also indicated that steroid treatment is associated with MetS rates after OLT.

Consensus interferon and ribavirin for patients with chronic hepatitis C and failure of previous interferon-alpha therapy.

Abstract: Background: The efficacy of consensus interferon (CIFN), a synthetic IFN with optimised in vitro activity, was assessed in chronic hepatitis C virus (HCV) patients who had failed the pretreatment with interferon‐α (IFNα) and ribavirin.

Survival analysis of proposed BCLC-B subgroups in hepatocellular carcinoma patients.

The BCLC‐staging system is used to facilitate treatment decisions in patients with hepatocellular carcinoma (HCC). Owing to the observed clinical heterogeneity of the intermediate stage BCLC‐B, a subclassification was proposed taking Child–Pugh score and extended criteria for transplantation into account. Analysis of the prognostic significance of a proposed subclassification of the BCLC‐B score in a European cohort of HCC patients.

EGF and HGF levels are increased during active HBV infection and enhance survival signaling through extracellular matrix interactions in primary human hepatocytes

The hepatitis B virus (HBV) is a major causative agent of chronic liver disease and subsequent liver cirrhosis worldwide. The reduced sensitivity of virus‐infected liver cells to apoptosis may play a role in the failure to remove virus‐infected cells and eventually promote viral chronicity. The purpose of our study was to investigate whether survival factors induced during compensatory liver regeneration may protect hepatocytes against apoptosis. We evaluated the serum levels of hepatocyte growth factor (HGF) and epidermal growth factor (EGF) in HBV‐infected patients and found significant increases in HGF and EGF in patients with active virus infection. In primary human hepatocytes we show that HGF and EGF have a protective effect against CD95‐mediated apoptosis and cytotoxic T‐cell killing. Simultaneous treatment with both regeneration factors enhanced the cytoprotective effect. The PI 3‐K/Akt kinase inhibitor, wortmannin, and the STAT3 pathway inhibitor, Tyrphostin AG490, both effectively attenuated the cytoprotective effect of HGF and EGF. Furthermore, we show an EGF/HGF‐dependent upregulation of β1‐integrin chains, increased adhesion to extracellular matrix and an increase in focal adhesions, suggesting outside‐in signaling from the extracellular matrix as an additional cytoprotective mechanism. Our study demonstrates that HGF and EGF can interfere with CD95‐mediated apoptosis and the action of cytotoxic T‐cells through multiple mechanisms in human hepatocytes. Together our results argue that a survival mileau generated by activation of liver regeneration factors may be a risk factor for establishing viral persistence.