TY - JOUR A1 - Sirtl, Simon A1 - Knoll, Gertrud A1 - Dieu Thuy, Trinh A1 - Lang, Isabell A1 - Siegmund, Daniela A1 - Gross, Stefanie A1 - Schuler-Thurner, Beatrice A1 - Neubert, Patrick A1 - Jantsch, Jonathan A1 - Wajant, Harald A1 - Ehrenschwender, Martin T1 - Hypertonicity-enforced BCL-2 addiction unleashes the cytotoxic potential of death receptors JF - Oncogene N2 - Attempts to exploit the cytotoxic activity of death receptors (DR) for treating cancer have thus far been disappointing. DR activation in most malignant cells fails to trigger cell death and may even promote tumor growth by activating cell death-independent DR-associated signaling pathways. Overcoming apoptosis resistance is consequently a prerequisite for successful clinical exploitation of DR stimulation. Here we show that hyperosmotic stress in the tumor microenvironment unleashes the deadly potential of DRs by enforcing BCL-2 addiction of cancer cells. Hypertonicity robustly enhanced cytotoxicity of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and other DR ligands in various cancer entities. Initial events in TRAIL DR signaling remained unaffected, but hypertonic conditions unlocked activation of the mitochondrial death pathway and thus amplified the apoptotic signal. Mechanistically, we demonstrate that hyperosmotic stress imposed a BCL-2-addiction on cancer cells to safeguard the integrity of the outer mitochondrial membrane (OMM), essentially exhausting the protective capacity of BCL-2-like pro-survival proteins. Deprivation of these mitochondrial safeguards licensed DR-generated truncated BH3-interacting domain death agonist (tBID) to activate BCL-2-associated X protein (BAX) and initiated mitochondrial outer membrane permeabilization (MOMP). Our work highlights that hyperosmotic stress in the tumor environment primes mitochondria for death and lowers the threshold for DR-induced apoptosis. Beyond TRAIL-based therapies, our findings could help to strengthen the efficacy of other apoptosis-inducing cancer treatment regimens. KW - apoptosis KW - cancer microenvironment KW - cytokines Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-238327 VL - 37 ER - TY - JOUR A1 - Ben Khaled, Najib A1 - Hammer, Katharina A1 - Ye, Liangtao A1 - Alnatsha, Ahmed A1 - Widholz, Sebastian A. A1 - Piseddu, Ignazio A1 - Sirtl, Simon A1 - Schneider, Julia A1 - Munker, Stefan A1 - Mahajan, Ujjwal Mukund A1 - Montero, Juan José A1 - Griger, Joscha A1 - Mayerle, Julia A1 - Reiter, Florian P. A1 - De Toni, Enrico N. T1 - TRAIL receptor targeting agents potentiate PARP inhibitor efficacy in pancreatic cancer independently of BRCA2 mutation status JF - Cancers N2 - Chemotherapy, the standard treatment for pancreatic ductal adenocarcinoma (PDAC), has only a modest effect on the outcome of patients with late-stage disease. Investigations of the genetic features of PDAC have demonstrated a frequent occurrence of mutations in genes involved in homologous recombination (HR), especially in the breast cancer susceptibility gene 2 (BRCA2). Olaparib, a poly(ADP-ribose) polymerase (PARP) inhibitor, is approved as a maintenance treatment for patients with advanced PDAC with germline BRCA1/2 mutations following a platinum-containing first-line regimen. Limitations to the use of PARP inhibitors are represented by the relatively small proportion of patients with mutations in BRCA1/2 genes and the modest capability of these substances of inducing objective response. We have previously shown that pancreatic cancer with BRCA2 mutations exhibits a remarkably enhanced sensitivity towards tumor-necrosis-factor-related apoptosis-inducing ligand (TRAIL) receptor-stimulating agents. We thus aimed to investigate the effect of combined treatment with PARP inhibitors and TRAIL receptor-stimulating agents in pancreatic cancer and its dependency on the BRCA2 gene status. The respective effects of TRAIL-targeting agents and the PARP inhibitor olaparib or of their combination were assessed in pancreatic cancer cell lines and patient-derived organoids. In addition, BRCA2-knockout and -complementation models were investigated. The effects of these agents on apoptosis, DNA damage, cell cycle, and receptor surface expression were assessed by immunofluorescence, Western blot, and flow cytometry. PARP inhibition and TRAIL synergized to cause cell death in pancreatic cancer cell lines and PDAC organoids. This effect proved independent of BRCA2 gene status in three independent models. Olaparib and TRAIL in combination caused a detectable increase in DNA damage and a concentration-dependent cell cycle arrest in the G2/M and S cell cycle phases. Olaparib also significantly increased the proportion of membrane-bound death receptor 5. Our results provide a preclinical rationale for the combination of PARP inhibitors and TRAIL receptor agonists for the treatment of pancreatic cancer and suggest that the use of PARP inhibitors could be extended to patients without BRCA2 mutations if used in combination with TRAIL agonists. KW - apoptosis KW - DNA damage KW - pancreatic neoplasms KW - poly(ADP-ribose) polymerase inhibitors KW - TNF-related apoptosis-inducing ligand Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-290884 SN - 2072-6694 VL - 14 IS - 21 ER - TY - JOUR A1 - Siegmund, Daniela A1 - Wagner, Jennifer A1 - Wajant, Harald T1 - TNF receptor associated factor 2 (TRAF2) signaling in cancer JF - Cancers N2 - Tumor necrosis factor (TNF) receptor associated factor-2 (TRAF2) has been originally identified as a protein interacting with TNF receptor 2 (TNFR2) but also binds to several other receptors of the TNF receptor superfamily (TNFRSF). TRAF2, often in concert with other members of the TRAF protein family, is involved in the activation of the classical NFκB pathway and the stimulation of various mitogen-activated protein (MAP) kinase cascades by TNFRSF receptors (TNFRs), but is also required to inhibit the alternative NFκB pathway. TRAF2 has also been implicated in endoplasmic reticulum (ER) stress signaling, the regulation of autophagy, and the control of cell death programs. TRAF2 fulfills its functions by acting as a scaffold, bringing together the E3 ligase cellular inhibitor of apoptosis-1 (cIAP1) and cIAP2 with their substrates and various regulatory proteins, e.g., deubiquitinases. Furthermore, TRAF2 can act as an E3 ligase by help of its N-terminal really interesting new gene (RING) domain. The finding that TRAF2 (but also several other members of the TRAF family) interacts with the latent membrane protein 1 (LMP1) oncogene of the Epstein–Barr virus (EBV) indicated early on that TRAF2 could play a role in the oncogenesis of B-cell malignancies and EBV-associated non-keratinizing nasopharyngeal carcinoma (NPC). TRAF2 can also act as an oncogene in solid tumors, e.g., in colon cancer by promoting Wnt/β-catenin signaling. Moreover, tumor cell-expressed TRAF2 has been identified as a major factor-limiting cancer cell killing by cytotoxic T-cells after immune checkpoint blockade. However, TRAF2 can also be context-dependent as a tumor suppressor, presumably by virtue of its inhibitory effect on the alternative NFκB pathway. For example, inactivating mutations of TRAF2 have been associated with tumor development, e.g., in multiple myeloma and mantle cell lymphoma. In this review, we summarize the various TRAF2-related signaling pathways and their relevance for the oncogenic and tumor suppressive activities of TRAF2. Particularly, we discuss currently emerging concepts to target TRAF2 for therapeutic purposes. KW - apoptosis KW - autophagy KW - B-cell lymphoma KW - cellular inhibitor of apoptosis 1/2 (cIAP1/2) KW - necroptosis KW - nuclear factor ‘kappa-light-chain-enhancer’ of activated B-cells (NFκB) KW - tumor necrosis factor (TNF) KW - TNF receptor associated factor 2 (TRAF2) Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286073 SN - 2072-6694 VL - 14 IS - 16 ER - TY - JOUR A1 - John, Katharina A1 - Franck, Martin A1 - Al Aoua, Sherin A1 - Rau, Monika A1 - Huber, Yvonne A1 - Schattenberg, Joern M. A1 - Geier, Andreas A1 - Bahr, Matthias J. A1 - Wedemeyer, Heiner A1 - Schulze-Osthoff, Klaus A1 - Bantel, Heike T1 - Non-invasive detection of fibrotic NASH in NAFLD patients with low or intermediate FIB-4 JF - Journal of Clinical Medicine N2 - Background: Non-alcoholic steatohepatitis (NASH) and fibrosis are the main prognostic factors in non-alcoholic fatty liver disease (NAFLD). The FIB-4 score has been suggested as an initial test for the exclusion of progressed fibrosis. However, increasing evidence suggests that also NASH patients with earlier fibrosis stages are at risk of disease progression, emphasizing the need for improved non-invasive risk stratification. Methods: We evaluated whether the apoptosis biomarker M30 can identify patients with fibrotic NASH despite low or intermediate FIB-4 values. Serum M30 levels were assessed by ELISA, and FIB-4 was calculated in an exploration (n = 103) and validation (n = 100) cohort of patients with histologically confirmed NAFLD. Results: The majority of patients with low FIB-4 (cut-off value < 1.3) in the exploration cohort revealed increased M30 levels (>200 U/L) and more than 80% of them had NASH, mostly with fibrosis. NASH was also detected in all patients with intermediate FIB-4 (1.3 to 2.67) and elevated M30, from which ~80% showed fibrosis. Importantly, in the absence of elevated M30, most patients with FIB-4 < 1.3 and NASH showed also no fibrosis. Similar results were obtained in the validation cohort. Conclusions: The combination of FIB-4 with M30 enables a more reliable identification of patients at risk for progressed NAFLD and might, therefore, improve patient stratification. KW - apoptosis KW - biomarker KW - fibrosis KW - FIB-4 KW - NAFLD KW - NASH KW - keratin-18 KW - M30 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-281824 SN - 2077-0383 VL - 11 IS - 15 ER - TY - JOUR A1 - Becker, Philip P. A1 - Rau, Monika A1 - Schmitt, Johannes A1 - Malsch, Carolin A1 - Hammer, Christian A1 - Bantel, Heike A1 - Müllhaupt, Beat A1 - Geier, Andreas T1 - Performance of serum microRNAs -122, -192 and -21 as biomarkers in patients with non-alcoholic steatohepatitis JF - PLoS ONE N2 - Objectives Liver biopsies are the current gold standard in non-alcoholic steatohepatitis (NASH) diagnosis. Their invasive nature, however, still carries an increased risk for patients' health. The development of non-invasive diagnostic tools to differentiate between bland steatosis (NAFL) and NASH remains crucial. The aim of this study is the evaluation of investigated circulating microRNAs in combination with new targets in order to optimize the discrimination of NASH patients by non-invasive serum biomarkers. Methods Serum profiles of four microRNAs were evaluated in two cohorts consisting of 137 NAFLD patients and 61 healthy controls. In a binary logistic regression model microRNAs of relevance were detected. Correlation of microRNA appearance with known biomarkers like ALT and CK18-Asp396 was evaluated. A simplified scoring model was developed, combining the levels of microRNA in circulation and CK18-Asp396 fragments. Receiver operating characteristics were used to evaluate the potential of discriminating NASH. Results The new finding of our study is the different profile of circulating miR-21 in NASH patients (p<0.0001). Also, it validates recently published results of miR-122 and miR-192 to be differentially regulated in NAFL and NASH. Combined microRNA expression profiles with CK18-Asp396 fragment level scoring model had a higher potential of NASH prediction compared to other risk biomarkers (AUROC = 0.83, 95% CI = 0.754-0.908; p<0.001). Evaluation of score model for NAFL (Score = 0) and NASH (Score = 4) had shown high rates of sensitivity (91%) and specificity (83%). Conclusions Our study defines candidates for a combined model of miRNAs and CK18-Asp396 levels relevant as a promising expansion for diagnosis and in turn treatment of NASH. KW - fatty liver disease KW - independent marker KW - expression KW - injury KW - NAFLD KW - circulating micrornas KW - caspase activation KW - fibrosis KW - miR-122 KW - apoptosis Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-145147 VL - 10 IS - 11 ER - TY - JOUR A1 - Rasche, Leo A1 - Duell, Johannes A1 - Morgner, Charlotte A1 - Chatterjee, Manik A1 - Hensel, Frank A1 - Rosenwald, Andreas A1 - Einsele, Hermann A1 - Topp, Max S. A1 - Brändlein, Stephanie T1 - The Natural Human IgM Antibody PAT-SM6 Induces Apoptosis in Primary Human Multiple Myeloma Cells by Targeting Heat Shock Protein GRP78 JF - PLoS ONE N2 - In contrast to other haematological malignancies, targeted immunotherapy has not entered standard treatment regimens for de novo or relapsed multiple myeloma (MM) yet. While a number of IgG-formatted monoclonal antibodies are currently being evaluated in clinical trials in MM, our study aimed to investigate whether the fully human IgM monoclonal antibody PAT-SM6 that targets a tumour-specific variant of the heat shock protein GRP78 might be an attractive candidate for future immunotherapeutic approaches. We here show that GRP78 is stably and consistently expressed on the surface on tumour cells from patients with de novo, but also relapsed MM and that binding of PAT-SM6 to MM cells can specifically exert cytotoxic effects on malignant plasma cells, whereas non-malignant cells are not targeted. We demonstrate that the induction of apoptosis and, to a lesser extent, complement dependent cytotoxicity is the main mode of action of PAT-SM6, whereas antibody dependent cellular cytotoxicity does not appear to contribute to the cytotoxic properties of this antibody. Given the favourable safety profile of PAT-SM6 in monkeys, but also in a recent phase I trial in patients with malignant melanoma, our results form the basis for a planned phase I study in patients with relapsed MM. KW - cytotoxicity KW - apoptosis KW - immunohistochemistry techniques KW - enzyme-linked immunoassays KW - multiple myeloma KW - cell staining KW - cell binding KW - complement system Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-130125 VL - 8 IS - 5 ER - TY - JOUR A1 - Loeffler, Claudia A1 - Loeffler, Jürgen A1 - Kobsar, Anna A1 - Speer, Christian P. A1 - Eigenthaler, Martin T1 - Septic Vs Colonizing Group B Streptococci Differentially Regulate Inflammation and Apoptosis in Human Coronary Artery Endothelial Cells - a Pilot Study JF - Journal of Pediatrics and Neonatal Care N2 - In this pilot study, we exemplify differences between a septic and a colonizing GBS strain during their interaction with Endothelial Cells by evaluating cytokine levels, surface and apoptosis-related molecules. These preliminary results indicate that in vitro infection using an exemplary septic GBS strain results in diminished activation of the innate immune response. KW - streptococci KW - apoptosis KW - inflammation KW - endothelial cells KW - innate immunity KW - early onset sepsis Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125596 VL - 2 IS - 2 ER - TY - JOUR A1 - Rauert, H. A1 - Stühmer, T. A1 - Bargou, R. A1 - Wajant, H. A1 - Siegmund, D. T1 - TNFR1 and TNFR2 regulate the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms N2 - The huge majority of myeloma cell lines express TNFR2 while a substantial subset of them failed to show TNFR1 expression. Stimulation of TNFR1 in the TNFR1-expressing subset of MM cell lines had no or only a very mild effect on cellular viability. Surprisingly, however, TNF stimulation enhanced cell death induction by CD95L and attenuated the apoptotic effect of TRAIL. The contrasting regulation of TRAIL- and CD95L-induced cell death by TNF could be traced back to the concomitant NFjBmediated upregulation of CD95 and the antiapoptotic FLIP protein. It appeared that CD95 induction, due to its strength, overcompensated a rather moderate upregulation of FLIP so that the net effect of TNF-induced NFjB activation in the context of CD95 signaling is pro-apoptotic. TRAIL-induced cell death, however, was antagonized in response to TNF because in this context only the induction of FLIP is relevant. Stimulation of TNFR2 in myeloma cells leads to TRAF2 depletion. In line with this, we observed cell death induction in TNFR1-TNFR2-costimulated JJN3 cells. Our studies revealed that the TNF-TNF receptor system adjusts the responsiveness of the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms that generate a highly context-dependent net effect on myeloma cell survival. KW - Medizin KW - apoptosis KW - CD95 KW - multiple myeloma KW - NFkB KW - TNF KW - TRAIL Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-76092 ER -