14 results on '"Alexander L. Gerbes"'
Search Results
2. p70 Ribosomal Protein S6 Kinase Is a Checkpoint of Human Hepatic Stellate Cell Activation and Liver Fibrosis in MiceSummary
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Florian P. Reiter, Liangtao Ye, Andrea Ofner, Tobias S. Schiergens, Andreas Ziesch, Lydia Brandl, Najib Ben Khaled, Simon Hohenester, Ralf Wimmer, Renate Artmann, Yulong He, Serene M.L. Lee, Doris Mayr, Changhua Zhang, Alexander L. Gerbes, Julia Mayerle, Gerald Denk, and Enrico N. De Toni
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Fibrosis ,Cirrhosis ,Chronic Liver Disease ,Transforming Growth Factor-β ,Platelet-Derived Growth Factor BB ,Diseases of the digestive system. Gastroenterology ,RC799-869 - Abstract
Background & Aims: Progression of chronic liver disease (CLD) to liver cirrhosis and liver cancer is a major global cause of morbidity and mortality. Treatment options capable of inhibiting progression of liver fibrosis when etiological treatment of CLD is not available or fails have yet to be established. We investigated the role of serine/threonine kinase p70 ribosomal protein S6 kinase (p70S6K) as checkpoint of fibrogenesis in hepatic stellate cells (HSCs) and as target for the treatment of liver fibrosis. Approach & Results: Immunohistochemistry was used to assess p70S6K expression in liver resection specimen. Primary human or murine HSCs from wild-type or p70S6K–/– mice as well as LX-2 cells were used for in vitro experiments. Specific small interfering RNA or CEP-1347 were used to silence or inhibit p70S6K and assess its functional relevance in viability, contraction and migration assays, fluorescence-activated cell sorting, and Western blot. These results were validated in vivo by a chemical model of fibrogenesis using wild-type and p70S6K–/– mice. Expression of p70S6K was significantly increased in human cirrhotic vs noncirrhotic liver-tissue and progressively increased in vitro through activation of primary human HSCs. Conversely, p70S6K induced fibrogenic activation of HSCs in different models, including the small interfering RNA–based silencing of p70S6K in HSC lines, experiments with p70S6K–/– cells, and the pharmacological inhibition of p70S6K by CEP-1347. These findings were validated in vivo as p70S6K–/– mice developed significantly less fibrosis upon exposure to CCl4. Conclusions: We establish p70S6K as a checkpoint of fibrogenesis in vitro and in vivo and CEP-1347 as potential treatment option that can safely be used for long-term treatment.
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- 2022
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3. Drug‐Induced Liver Injury by Checkpoint Inhibitors: Benefit of a Causality Assessment Tool
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Sabine Weber, Andreas Benesic, Masatoshi Ishigami, and Alexander L. Gerbes
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Diseases of the digestive system. Gastroenterology ,RC799-869 - Published
- 2020
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4. Challenges and Future of Drug-Induced Liver Injury Research—Laboratory Tests
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Sabine Weber and Alexander L. Gerbes
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drug-induced liver injury ,hepatotoxicity ,biomarkers ,drug development ,adverse drug events ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Drug-induced liver injury (DILI) is a rare but potentially severe adverse drug event, which is also a major cause of study cessation and market withdrawal during drug development. Since no acknowledged diagnostic tests are available, DILI diagnosis poses a major challenge both in clinical practice as well as in pharmacovigilance. Differentiation from other liver diseases and the identification of the causative agent in the case of polymedication are the main issues that clinicians and drug developers face in this regard. Thus, efforts have been made to establish diagnostic testing methods and biomarkers in order to safely diagnose DILI and ensure a distinguishment from alternative liver pathologies. This review provides an overview of the diagnostic methods used in differential diagnosis, especially with regards to autoimmune hepatitis (AIH) and drug-induced autoimmune hepatitis (DI-AIH), in vitro causality methods using individual blood samples, biomarkers for diagnosis and severity prediction, as well as experimental predictive models utilized in pre-clinical settings during drug development regimes.
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- 2022
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5. Pretreatment with zinc protects Kupffer cells following administration of microbial products
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Jiang Zhang, Andreas Wieser, Hao Lin, Yuhui Fan, Hanwei Li, Tobias S. Schiergens, Julia Mayerle, Alexander L. Gerbes, and Christian J. Steib
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Primary non-parenchymal cell ,Spontaneous bacterial peritonitis ,Zinc ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Background: Systemic inflammation and severe fibrosis can reduce serum zinc levels, while zinc supplementation is reported to improve the prognosis of patients with chronic liver disease (CLD). Objectives: We aimed to investigate the clinical application of serum zinc in patients with CLD and the anti-infective mechanism of zinc supplementation. Methods: Based on the serum zinc level, 149 CLD patients were divided into 3 groups and their clinical parameters were compared. In in-vitro experiments, microbial isolates derived from patients were used to stimulate human liver non-parenchymal cells, and the zinc sulfate solution was added in certain experiments. The effect of zinc was compared by LDH and thromboxane A2 levels in the cell supernatant. Result: Compared with other groups, patients with low serum zinc levels had significantly higher C-reactive protein (CRP), total bilirubin, INR, creatinine, and MELD scores, while albumin and GOT levels were reduced. Only CRP and albumin were significantly correlated with serum zinc in both low and normal-zinc groups. Bacterial isolates significantly increased LDH levels in Kupffer cells (KCs) and stellate cells but had no effect on sinusoidal endothelial cells, whereas zinc pretreatment protected KCs but not stellate cells. Thromboxane A2 secreted by KCs can also be induced by bacterial stimulation, accompanied by increased gene expression of Myd88, MAPK and NF-kB, while zinc pretreatment can attenuate that. Conclusion: Serum zinc levels can be used to estimate infection and liver fibrosis in CLD patients. As a new antibacterial weapon, zinc supplementation acts on KCs through Myd88-MAPK related pathways.
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- 2020
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6. Data on chow, liver tissue and mitochondrial fatty acid compositions as well as mitochondrial proteome changes after feeding mice a western diet for 6â24 weeks
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Claudia Einer, Simon Hohenester, Ralf Wimmer, Lena Wottke, Renate Artmann, Sabine Schulz, Christian Gosmann, Alisha Simmons, Christin Leitzinger, Carola Eberhagen, Sabine Borchard, Sabine Schmitt, Stefanie M. Hauck, Christine von Toerne, Martin Jastroch, Ellen Walheim, Christian Rust, Alexander L. Gerbes, Bastian Popper, Doris Mayr, Max Schnurr, Angelika M. Vollmar, Gerald Denk, and Hans Zischka
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Computer applications to medicine. Medical informatics ,R858-859.7 ,Science (General) ,Q1-390 - Abstract
The data presented in this article describe the fatty acid composition of chow, liver tissue and isolated liver mitochondria from mice fed for 6â24 weeks with a high caloric western diet (WD) in comparison to control diet (normal diet, ND). The fatty acid composition was measured via gas chromatography flame ionization detection (GC-FID). Moreover, WD-induced mitochondrial protein changes are presented in this work and were analyzed by mass spectrometry (LCâMS/MS). For further interpretation and discussion of the presented data please refer to the research article entitled âMitochondrial adaptation in steatotic miceâ (Einer et al., 2017) [1].
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- 2017
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7. Albumin Might Attenuate Bacteria-Induced Damage on Kupffer Cells for Patients with Chronic Liver Disease
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Hao Lin, Yuhui Fan, Andreas Wieser, Jiang Zhang, Ivonne Regel, Hanno Nieß, Julia Mayerle, Alexander L. Gerbes, and Christian J. Steib
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hepatic non-parenchymal cells ,albumin ,chronic liver diseases ,bacteria ,Cytology ,QH573-671 - Abstract
Chronic liver diseases (CLDs) are complex diseases that cause long-term inflammation and infection, which in turn accelerate their development. The usage of albumin in patients with CLDs has been debated for years. Human serum albumin (HSA) plays a key role in immunomodulation during the process of CLDs. The correlation between albumin and C-reactive protein (CRP) in CLD patients was analyzed by linear regression with the Pearson statistic. The damage of THP-1 and primary cells was evaluated by measuring the lactate dehydrogenase (LDH) in the supernatant. Immunofluorescence staining was performed to determine underlying pathways in Kupffer cells (KCs). Albumin negatively correlated with infection in patients with CLDs. In vitro experiments with THP-1 cells and KCs showed that albumin reduced LDH release after stimulation with bacterial products, while no differences in hepatic stellate cells (HSCs) and sinusoidal endothelial cells (SECs) were detected. Moreover, immunofluorescence staining revealed an increase of p-ERK and p-NF-kB p65 density after albumin treatment of KCs stimulated by bacterial products. In conclusion, albumin could assist CLD patients in alleviating inflammation caused by bacterial products and might be beneficial to patients with CLDs by securing KCs from bacteria-induced damage, providing a compelling rationale for albumin therapy in patients with CLDs.
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- 2021
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8. Ischemic Postconditioning (IPostC) Protects Fibrotic and Cirrhotic Rat Livers after Warm Ischemia
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Julia Schewe, Marie-Christine Makeschin, Ingrid Liss, Doris Mayr, Jiang Zhang, Andrej Khandoga, Simon Rothenfußer, Max Schnurr, Alexander L. Gerbes, and Christian J. Steib
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Diseases of the digestive system. Gastroenterology ,RC799-869 - Abstract
Background. Decreased organ function following liver resection is a major clinical issue. The practical method of ischemic postconditioning (IPostC) has been studied in heart diseases, but no data exist regarding fibrotic livers. Aims. We aimed to determine whether IPostC could protect healthy, fibrotic, and cirrhotic livers from ischemia reperfusion injury (IRI). Methods. Fibrosis was induced in male SD rats using bile duct ligation (BDL, 4 weeks), and cirrhosis was induced using thioacetamide (TAA, 18 weeks). Fibrosis and cirrhosis were histologically confirmed using HE and EvG staining. For healthy, fibrotic, and cirrhotic livers, isolated liver perfusion with 90 min of warm ischemia was performed in three groups (each with n=8): control, IPostC 8x20 sec, and IPostC 4x60 sec. additionally, healthy livers were investigated during a follow-up study. Lactate dehydrogenase (LDH) and thromboxane B2 (TXB2) in the perfusate, as well as bile flow (healthy/TAA) and portal perfusion pressure, were measured. Results. LDH and TXB2 were reduced, and bile flow was increased by IPostC, mainly in total and in the late phase of reperfusion. The follow-up study showed that the perfusate derived from a postconditioned group had much less damaging potential than perfusate derived from the nonpostconditioned group. Conclusion. IPostC following warm ischemia protects healthy, fibrotic, and cirrhotic livers against IRI. Reduced efflux of TXB2 is one possible mechanism for this effect of IPostC and increases sinusoidal microcirculation. These findings may help to improve organ function and recovery of patients after liver resection.
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- 2019
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9. IL-18 But Not IL-1 Signaling Is Pivotal for the Initiation of Liver Injury in Murine Non-Alcoholic Fatty Liver Disease
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Simon Hohenester, Veronika Kanitz, Tobias Schiergens, Claudia Einer, Jutta Nagel, Ralf Wimmer, Florian P. Reiter, Alexander L. Gerbes, Enrico N. De Toni, Christian Bauer, Lesca Holdt, Doris Mayr, Christian Rust, Max Schnurr, Hans Zischka, Andreas Geier, and Gerald Denk
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NAFLD ,Western diet ,NLRP3 ,inflammasome ,interleukin 1 ,interleukin 18 ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Non-alcoholic fatty liver disease (NAFLD) is rising in prevalence, and a better pathophysiologic understanding of the transition to its inflammatory phenotype (NASH) is key to the development of effective therapies. To evaluate the contribution of the NLRP3 inflammasome and its downstream effectors IL-1 and IL-18 in this process, we applied the true-to-life “American lifestyle-induced obesity syndrome” (ALiOS) diet mouse model. Development of obesity, fatty liver and liver damage was investigated in mice fed for 24 weeks according to the ALiOS protocol. Lipidomic changes in mouse livers were compared to human NAFLD samples. Receptor knockout mice for IL-1 and IL-18 were used to dissect the impact of downstream signals of inflammasome activity on the development of NAFLD. The ALiOS diet induced obesity and liver steatosis. The lipidomic changes closely mimicked changes in human NAFLD. A pro-inflammatory gene expression pattern in liver tissue and increased serum liver transaminases indicated early liver damage in the absence of histological evidence of NASH. Mechanistically, Il-18r−/−- but not Il-1r−/− mice were protected from early liver damage, possibly due to silencing of the pro-inflammatory gene expression pattern. Our study identified NLRP3 activation and IL-18R-dependent signaling as potential modulators of early liver damage in NAFLD, preceding development of histologic NASH.
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- 2020
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10. Proteomics Analysis of Monocyte-Derived Hepatocyte-Like Cells Identifies Integrin Beta 3 as a Specific Biomarker for Drug-Induced Liver Injury by Diclofenac
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Diana Dragoi, Andreas Benesic, Garwin Pichler, Nils A. Kulak, Harald S. Bartsch, and Alexander L. Gerbes
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DILI ,biomarker ,proteomics ,drug-development ,monocyte-derived hepatocyte-like cells ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Idiosyncratic drug-induced liver injury (iDILI) is a major cause of acute liver failure resulting in liver transplantation or death. Prediction and diagnosis of iDILI remain a great challenge, as current models provide unsatisfying results in terms of sensitivity, specificity, and prognostic value. The absence of appropriate tools for iDILI detection also impairs the development of reliable biomarkers. Here, we report on a new method for identification of drug-specific biomarkers. We combined the advantages of monocyte-derived hepatocyte-like (MH) cells, able to mimic individual characteristics, with those of a novel mass spectrometry-based proteomics technology to assess potential biomarkers for Diclofenac-induced DILI. We found over 2,700 proteins differentially regulated in MH cells derived from individual patients. Herefrom, we identified integrin beta 3 (ITGB3) to be specifically upregulated in Diclofenac-treated MH cells from Diclofenac-DILI patients compared to control groups. Finally, we validated ITGB3 by flow cytometry analysis of whole blood and histological staining of liver biopsies derived from patients diagnosed with Diclofenac-DILI. In summary, our results show that biomarker candidates can be identified by proteomics analysis of MH cells. Application of this method to a broader range of drugs in the future will exploit its full potential for the development of drug-specific biomarkers. Data are available via ProteomeXchange with identifier PXD008918.
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- 2018
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11. High age and low sodium urine concentration are associated with poor survival in patients with hepatorenal syndrome
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Matthias Hinz, Alexander Wree, Christoph Jochum, Lars P. Bechmann, Fuat Saner, Alexander L. Gerbes, Guido Gerken, and A.l.i. Canbay, M.D.
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Terlipressin ,Urinary sodium ,Predictors of response and survival ,Overall mortality ,Specialties of internal medicine ,RC581-951 - Abstract
Background. Combination therapy with terlipressin and albumin substitution is considered a widely accepted treatment regimen for patients with hepatorenal syndrome (HRS). However, only half of the patients respond to treatment and to date albumin substitution and terlipressin therapy are among the most expensive medical treatments available for patients with liver diseases. Thus, we aimed to identify clinical and etiological parameters to predict treatment response and overall mortality in patients with HRS.Material and methods. We retrospectively evaluated 21 patients, 13 male/8 female, aged 43-72 years with HRS. Four patients were transplanted after following combination treatment. Terlipressin was administered by continuous intravenous perfusion (2–6 mg/d) and albumin drips (50 mg) were given daily. Treatment response was defined by a decrease in serum creatinine level to < 1.5 mg/dL or by a > 50% reduction of the baseline concentration.Results. 57% of the patients responded to treatment, which was associated with improved survival at day 60, compared to non-responders. However, the overall mortality was not different between the two groups. Median age of 63 years was a significant negative predictor for therapy response. High baseline urinary sodium levels were of prognostic value for survival. The Model of End stage Liver Disease score (MELD score) did not correlate with therapy response.Conclusion. In conclusion high age is a predictor of non-response. Low urinary sodium before treatment is associated with poor survival. Terli-pressin and albumin co-treatment is associated with increased two-months survival rate. This seemingly moderate extension in survival rate can, however, be decisive for obtaining liver transplantation.
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- 2013
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12. Ischaemic and pharmacological preconditionings protect liver via adenosine and redox status following hepatic ischaemia/reperfusion in rats.
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Hussam H. Ajamieh, Eduardo Candelario-jalil, Olga Sonia León Fernández, and Alexander L Gerbes
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ISCHEMIA ,PHARMACOLOGY ,LIVER diseases ,ADENOSINES ,OXIDATION-reduction reaction ,NITRIC oxide ,OXIDATIVE stress ,LABORATORY rats - Abstract
Although IPC (ischaemic preconditioning) is considered as a protective strategy in HI/R (hepatic ischaemia/reperfusion), the mechanisms for this effect have not been fully elucidated. In the present study we investigate whether PPC (pharmacological preconditioning) by transient activation of A1R (adenosine A1receptor) protects against long-term HI/R and whether the protective effects of IPC depend on A1R activation and whether both preconditionings affect remote organs. Wistar rats underwent IPC and long-term HI/R. Another set of animals were pharmacologically preconditioned with the A1R-agonist CCPA [2-chloro-N6-cyclopentyladenosine; 0.1 mg/kg of body weight, i.p. (intraperitoneally)] 24 h before HI/R. In other groups, rats received an A1R-antagonist, DPCPX (1,3-dipropyl-8-cyclopentylxanthine; 0.1 mg/kg of body weight, i.p.) 24 h before HI/R. Hepatic damage was evaluated by transaminase [AST (aspartate transaminase), ALT (alanine transaminase)] release; inflammation was assessed by hepatic MPO (myeloperoxidase) and serum TNFα (tumour necrosis factor α) and NO; oxidative stress was estimated by MDA (malondialdehyde) and 4-HDA (4-hydroxyalkenals), SOD (superoxide dismutase) activity, GSH and ADA (adenosine deaminase) as adenosine metabolism. Both preconditionings protected liver and lung against HI/R as indicated by the reduction in transaminases, MPO, MDA+4-HDA, NO, TNFα and ADA activity as compared with HI/R (P<0.05). However, pre-treatment with DPCPX abolished the protective effects of IPC and PPC. Preconditionings induced a significant increase in hepatic MnSOD (manganese SOD) activity and NO generation compared with the sham group, and this activity was abolished by DPCPX pre-treatment. A1R activation induced hepatic delayed preconditioning and blockade of A1R abolished hepatic IPC. IPC, as well as PPC, were able to prevent lung damage. These protective effects are associated with a reduction in oxidative stress, inflammation and endogenous antioxidant preservation. [ABSTRACT FROM AUTHOR]
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- 2008
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13. Rapid development of esophageal squamous cell carcinoma after liver transplantation for alcohol-induced cirrhosis.
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Silke Kenngott, Alexander L. Gerbes, Rolf Schauer, and Manfred Bilzer
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LIVER transplantation , *ESOPHAGUS , *SQUAMOUS cell carcinoma , *ENDOSCOPY - Abstract
Liver transplant recipients have an increased risk of developing de novo malignancies. It is generally accepted that chronic alcohol abuse is a contributive factor in the pathogenesis of several malignancies, in particular, of oropharyngeal squamous cell carcinoma (SCC). Thus, patients with end-stage alcohol-induced cirrhosis could be at risk of esophageal SCC following orthotopic liver transplantation (OLT). From January 1986 to December 1997 a total of 313 patients underwent OLT for various indications. Of these patients, 72 had alcohol-related cirrhosis. Oropharyngeal and esophageal malignancies after OLT were not observed in non-alcoholic patients. In contrast, these malignancies were diagnosed in three male patients who underwent transplantation for alcohol-induced cirrhosis (incidence 4.2%). Furthermore, all patients had a history of tobacco abuse. The tumors were located in the tongue of one patient and in the esophagus of two patients. While SCC of the tongue became apparent 5 years after OLT, esophageal SCC was detected 8 and 16 months after transplantation. Shortly before transplantation, endoscopy of the esophagus had not revealed evidence of pre-malignant dysplastic lesions in any of these patients. Thus, esophageal SCC may develop rapidly in patients undergoing transplantation for alcohol-related cirrhosis with a history of tobacco abuse before liver transplantation, which warrants careful post-transplant screening of these patients. [ABSTRACT FROM AUTHOR]
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- 2003
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14. Microsatellite instability, KRAS mutations and cellular distribution of TRAIL-receptors in early stage colorectal cancer.
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Lydia Kriegl, Andreas Jung, David Horst, Antonia Rizzani, Rene Jackstadt, Heiko Hermeking, Eike Gallmeier, Alexander L Gerbes, Thomas Kirchner, Burkhard Göke, and Enrico N De Toni
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Medicine ,Science - Abstract
The fact that the receptors for the TNF-related apoptosis inducing ligand (TRAIL) are almost invariably expressed in colorectal cancer (CRC) represents the rationale for the employment of TRAIL-receptors targeting compounds for the therapy of patients affected by this tumor. Yet, first reports on the use of these bioactive agents provided disappointing results. We therefore hypothesized that loss of membrane-bound TRAIL-R might be a feature of some CRC and that the evaluation of membrane staining rather than that of the overall expression of TRAIL-R might predict the response to TRAIL-R targeting compounds in this tumor.Thus, we evaluated the immunofluorescence pattern of TRAIL-receptors and E-cadherin to assess the fraction of membrane-bound TRAIL-receptors in 231 selected patients with early-stage CRC undergoing surgical treatment only. Moreover, we investigated whether membrane staining for TRAIL-receptors as well as the presence of KRAS mutations or of microsatellite instability (MSI) had an effect on survival and thus a prognostic effect.As expected, almost all CRC samples stained positive for TRAIL-R1 and 2. Instead, membrane staining for these receptors was positive in only 71% and 16% of samples respectively. No correlation between KRAS mutation status or MSI-phenotype and prognosis could be detected. TRAIL-R1 staining intensity correlated with survival in univariate analysis, but only membranous staining of TRAIL-R1 and TRAIL-R2 on cell membranes was an independent predictor of survival (cox multivariate analysis: TRAIL-R1: p = 0.019, RR 2.06[1.12-3.77]; TRAIL-R2: p = 0.033, RR 3.63[1.11-11.84]).In contrast to the current assumptions, loss of membrane staining for TRAIL-receptors is a common feature of early stage CRC which supersedes the prognostic significance of their staining intensity. Failure to achieve therapeutic effects in recent clinical trials using TRAIL-receptors targeting compounds might be due to insufficient selection of patients bearing tumors with membrane-bound TRAIL-receptors.
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- 2012
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