Steffen Zopf

A genome-wide association study confirms PNPLA3 and identifies TM6SF2 and MBOAT7 as risk loci for alcohol-related cirrhosis

Alcohol misuse is the leading cause of cirrhosis and the second most common indication for liver transplantation in the Western world. We performed a genome-wide association study for alcohol-related cirrhosis in individuals of European descent (712 cases and 1,426 controls) with subsequent validation in two independent European cohorts (1,148 cases and 922 controls). We identified variants in the MBOAT7 (P = 1.03 × 10−9) and TM6SF2 (P = 7.89 × 10−10) genes as new risk loci and confirmed rs738409 in PNPLA3 as an important risk locus for alcohol-related cirrhosis (P = 1.54 × 10−48) at a genome-wide level of significance. These three loci have a role in lipid processing, suggesting that lipid turnover is important in the pathogenesis of alcohol-related cirrhosis.

Apoptosis, proliferation and differentiation patterns are influenced by Zebularine and SAHA in pancreatic cancer models

Objective. Pancreatic cancer continues to be an urgent clinical problem. We used the novel DNA methyltransferase inhibitor Zebularine and the histone deacetylase inhibitor SAHA to investigate the epigenetic influence on viability and differentiation of the pancreatic cancer cell lines YAP C, DAN G and Panc-89 in vitro and in vivo. Material and methods. Cell vitality, proliferation and expression of PDX-1, cytokeratin 7 and 20, chromogranin A, vimentin, bax and bcl-2 were determined on the protein and mRNA level in vitro and in a subcutaneous xenograft model. Results. A time- and dose-dependent increase of apoptosis, paralleled by decreased proliferation, was observed after incubation with single agents or a combination therapy with lower concentrations. This was associated with up-regulation of pro-apoptotic bax and a phenotypic stabilization by the enhanced expression of cytokeratin 7. In vivo, growth of xenografts was delayed with the most pronounced effect in Panc-89 after 1 week of daily intraperitoneal injections of Zebularine paralleled with CK7 up-regulation and down-regulation of dedifferentiation markers. Conclusions. Epigenetic modulation via inhibition of DNA methyltransferase and histone deacetylase induces apoptosis in human pancreatic cancer cells in vitro and delays xenograft growth in vivo, which is associated with a morphological/molecular phenotypic stabilization. These compounds may therefore be suitable as adjunctive therapeutic agents in the treatment of pancreatic cancer.

Advances in hepatitis C therapy: What is the current state - what come’s next?

Chronic hepatitis C virus (HCV) infection affects 80-160 million people worldwide and is one of the leading causes of chronic liver disease. It is only a few years ago that standard treatment regimes were based on pegylated interferon alpha and ribavirin. However, treatment of HCV has undergone a revolutionary change in recent years. The admission of the nucleotide polymerase inhibitor Sofosbuvir enabled an interferon-free regimen with direct antiviral agents (DAA). Meanwhile seven DAAs are available and can be applied in several combinations for 8 to 24 wk depending on HCV genotype and patient characteristics such as cirrhosis and chronic renal failure. High rates of sustained virological response (SVR) rates can be achieved with these novel drugs. Even in difficult to treat populations such as patients with liver cirrhosis, HCV-human immunodeficiency virus co-infections, after liver transplantion, or with chronic kidney disease comparable high rates of SVR can be achieved. The anticipated 2(nd) generation DAAs are strikingly effective in patients so far classified as difficult to treat including decompensated liver cirrhosis or post-transplant patients. These 2(nd) generations DAAs will have higher resistance barriers, higher antiviral effects and a pan-genotypic spectrum. This review highlights the current state of the art of antiviral treatment in hepatitis C and gives an outlook for upcoming therapies.

bcl-2-specific siRNAs restore Gemcitabine sensitivity in human pancreatic cancer cells

Gemcitabine has been shown to ameliorate disease related symptoms and to prolong overall survival in pancreatic cancer.Yet, resistance to Gemcitabine is commonly observed in this tumour entity and has been linked to increased expression of anti‐apoptotic bcl‐2. We therefore investigated if and to what extend silencing of bcl‐2 by specific siRNAs (siBCL2) might enhance Gemcitabine effects in human pancreatic carcinoma cells. siBCL2 was transfected into the pancreatic cancer cell line YAP C alone and 72 hrs before co‐incubation with different concentrations of Gemcitabine. Total protein and RNA were extracted for Western‐blot analysis and quantitative polymerase chain reaction. Pancreatic cancer xenografts in male nude mice were treated intraperitoneally with siBCL2 alone, Gemcitabine and control siRNA or Gemcitabine and siBCL2 for 21 days. Combination of both methods lead to a synergistic induction of apoptosis at otherwise ineffective concentrations of Gemcitabine. Tumour growth suppression was also potentiated by the combined treatment with siBCL2 and Gemcitabine in vivo and lead to increased TUNEL positivity. In contrast, non‐transformed human foreskin fibroblasts showed only minor responses to this treatment. Our results demonstrate that siRNA‐mediated silencing of anti‐apoptotic bcl‐2 enhances chemotherapy sensitivity in human pancreatic cancer cells in vitro and might lead to improved therapy responses in advanced stages of this disease.

Inhibition of DNA methyltransferase activity and expression by treatment with the pan-deacetylase inhibitor panobinostat in hepatocellular carcinoma cell lines

BackgroundHepatocellular carcinoma (HCC) still represents an unmet medical need. Epigenetic inactivation of tumor suppressor genes like RASSF1A or APC by overexpression of DNA methyltransferases (DNMTs) has been shown to be common in HCC and to be linked to the overall prognosis of patients. Inhibitors of protein and histone deacetylases (DACi) have been demonstrated to possess strong anti-tumor effects in HCC models.MethodsWe therefore investigated whether DACi also has any influence on the expression and activity of DNMTs and methylated target genes in HepG2 and Hep3B cell culture systems and in a xenograft model by immunohistochemistry, westernblotting, RT-qPCR and methylation-specific PCR.ResultsOur findings demonstrate a rapid inhibition of DNMT activity 6 h after treatment with 0.1 μM of the pan-DACi panobinostat. A downregulation of DNMT mRNAs and protein were also observed at later points in time. This loss of DNMT activity and expression was paralleled by a diminished methylation of the target genes RASSF1A and APC and a concomitant re-expression of APC mRNA and protein. Analysis of HepG2 xenograft specimens confirmed these results in vivo.ConclusionWe suggest a dual mode of action of DACi on DNA methylation status: a rapid inhibition of enzyme activity due to interference with posttranslational acetylation and a delayed effect on transcriptional control of DNMT genes by HDAC or miRNA mechanisms.

Different capabilities of morphological pattern formation and its association with the expression of differentiation markers in a xenograft model of human pancreatic cancer cell lines

Aims: New concepts of tumorigenesis favor an unregulated process recapitulating different stages of embryogenic development with dysregulation of transition states. The aim of our study was to investigate the possibility of differentiation pathways of human pancreatic cancer cell lines in vivo. Material and Methods: Different human pancreatic cancer cell lines (YAPC, DAN-G, CAPAN-1, PANC-1 and MIA PaCa-2) were implanted subcutaneously (3 × 106 cells) for 28 days in nude mice. Xenotransplants were characterized with histochemistry (HE, PAS), immunohistochemistry (cytokeratin (CK)7, CK8, CK18, CK19, CK20, vimentin, chromogranin A (Chr-A), α1-antichymotrypsin (α1-chym), β-catenin, laminin-5, pancreatic and duodenal homeobox gene 1 (pdx-1), sonic hedgehog protein (shh), Patched (ptc)), Western blotting and real-time PCR (CK7, CK8, CK20, Chr-A, pdx-1, shh, ptc). Results: Depending on three major morphologic phenotypes of tumor cell xenotransplants (ductal (YAPC), ductal/solid (DAN-G, CAPAN-1), solid (PANC-1, MIA PaCa-2)), a decrease of CK7/CK19 was found, accompanied by an increase of CK8/18 and vimentin. Predominantly the CK7-positive ductal phenotype (YAPC and DAN-G) was associated with pdx-1 expression, whereas the CK8-positive solid phenotype was associated with shh/ptc expression on protein and mRNA level. Additionally, CK-20 expression was mainly linked to the ductal phenotype, co-localized with nuclear β-catenin. The endocrine-exocrine transdifferentiation, as assessed by Chr-A and α1-chym, was on a constant low to moderate level in all xenotransplants. Finally, an intensive epithelial-mesenchymal interaction was observed by overexpression of laminin-5 at the invasion front. Conclusion: The observed patterns of morphology and molecular differentiation in human pancreatic cancer xenografts indicate that these cancer cell lines have different capa bilities of pattern formation in vivoassociated with molecular differentiation markers, especially of embryonic pancreatic development.

Early response to anti-tumoral treatment in hepatocellular carcinoma--can quantitative contrast-enhanced ultrasound predict outcome?

PURPOSE In order to detect an early response to anti-angiogenic therapy, this study aims at analyzing specific effects of a sorafenib-based regime on intra-tumoral D-CEUS flow parameters of patients with HCC. MATERIALS AND METHODS Videos of the arterial phase were captured before initiation of a therapy with sorafenib and 1 and 3 months after (n = 9). Patients receiving a non-anti-angiogenic therapy (TACE, n = 10) served as a comparison group. Cross-sectional imaging was performed at the same time points and patients were followed up for 1 year. RESULTS In the responder group (RE), the absolute (percentage) TTP was 11.28 s ± 2.03 s (1.00) before treatment, 13.60 s ± 1.52 s (1.53 ± 0.08) after one month (p = 0.0405), and 16.17 s ± 2.35 s (1.46 ± 0.07) after three months of treatment (p = 0.0071). The TTP increased significantly in the RE group as early as 1 month after initiation of sorafenib compared to the non-responder group. There were no significant differences in the non-responder group or between the NR and the TACE group at any time point. D-CEUS values from all sorafenib-treated patients showed good accordance with RECICL (response evaluation criteria in cancer of the liver) criteria (R2 = 0.7154, p = 0.0001). CONCLUSIONS Quantitative CEUS reveals variations of dynamic parameters of blood flow during anti-tumoral therapy in liver cancer patients. Further investigations and clinical trails have to confirm that the TTP is a promising parameter in the prediction of early response to sorafenib-based therapy.

Combination of the deacetylase inhibitor panobinostat and the multi-kinase inhibitor sorafenib for the treatment of metastatic hepatocellular carcinoma - review of the underlying molecular mechanisms and first case report.

Advanced hepatocellular carcinoma still represents an unmet medical need that has only a limited overall survival despite the introduction of the multi-kinase inhibitor sorafenib. Recently, inhibitors of histone and other protein deacetylases have been established as novel therapeutic approaches to cancer diseases. We here review the molecular rationale for combining these two novel targeted therapies and report a patient with metastasized hepatocellular carcinoma who showed a partial remission of primary and metastatic lesions for five months after a combination therapy with sorafenib and the orally available pan-deacetylase inhibitor panobinostat.

Inducibility of microsomal liver function may differentiate cirrhotic patients with maintained compared with severely compromised liver reserve.

Background and Aim: Quantitative tests of liver function (QTLF) can be modulated by enzyme‐inducing agents. The objective of the study was to examine changes in QTLF after treatment with Phenobarbital, a potent cytochrome P450‐inducing agent.

Impact of Acoustic Radiation Force Impulse Imaging in Clinical Practice of Patients after Orthotopic Liver Transplantation

Background Acoustic radiation force impulse (ARFI) elastography is a reliable diagnostic device for quantitative non-invasive assessment of liver fibrosis in patients with chronic liver disease. The aim of our prospective study was to evaluate the impact of ARFI in patients after orthotopic liver transplantation (OLT). Therefore, we compared ARFI shear wave velocities with clinical features, non-invasive markers, and the histology of patients following OLT. Material/Methods Post-transplant patients underwent a clinical examination and blood samples were taken. B-mode and Doppler ultrasound (US) of the portal vein and the hepatic artery were performed. Subsequently, a minimum of 10 valid ARFI values were measured in the left and right liver lobe. Liver biopsy was performed if indicated. Results Between May 2012 and May 2014, 58 Patients after OLT were included in the prospective study. Laboratory markers and aspartate aminotransferase-to-platelet ratio index (APRI) correlated with ARFI values (r=0.44, p<0.001). The histological (n=22) fibrosis score (Ludwig) was significantly correlated with the ARFI of the biopsy site (r=0.55, p=0.008). The mean shear-wave velocities were significantly increased in advanced fibrosis (F≤2 1.57±0.57 m/s; F≥3 2.85±0.66 m/s; p<0.001), obstructive cholestasis and active viral hepatitis. The area under the receiver operating characteristic (AUROC) curves for the accuracy of ARFI were 74% (F≥1), 73% (F≥2), 93% (F≥3), and 80% (=F4). Conclusions ARFI elastography correlates well with laboratory values and with noninvasive and invasive markers of fibrosis in patients after OLT. In this regard, elevated ARFI-velocities should be interpreted with caution in the context of obstructive cholestasis and active viral disease.