Verena Haselmann1, Alexandra Kurz1, Uwe Bertsch2, Sebastian Hübner1, Monika Olempska-Müller1, Jürgen Fritsch2, Robert Häsler3, Andreas Pickl1, Hendrik Fritsche1, Franka Annewanter1, Christine Engler1, Barbara Fleig1, Alexander Bernt1, Christian Röder1, Hendrik Schmidt2, Christoph Gelhaus4, Charlotte Hauser5, Jan-Hendrik Egberts6, Carola Heneweer7, Anna Maria Rohde8, Christine Böger9, Uwe Knippschild10, Christoph Röcken9, Dieter Adam2, Henning Walczak11, Stefan Schütze2, Ottmar Janssen2, F Gregory Wulczyn8, Harald Wajant12, Holger Kalthoff1, Anna Trauzold13. 1. Division of Molecular Oncology, Institute for Experimental Cancer Research, University of Kiel, Kiel, Germany. 2. Institute of Immunology, University of Kiel, Kiel, Germany. 3. Institute of Clinical Molecular Biology, University of Kiel, Kiel, Germany. 4. Zoological Institute, University of Kiel, Kiel, Germany. 5. Division of Molecular Oncology, Institute for Experimental Cancer Research, University of Kiel, Kiel, Germany; Clinic for General Surgery, Visceral, Thoracic, Transplantation and Pediatric Surgery, University of Kiel, Kiel, Germany. 6. Clinic for General Surgery, Visceral, Thoracic, Transplantation and Pediatric Surgery, University of Kiel, Kiel, Germany. 7. Clinic for Diagnostic Radiology, University of Kiel, Kiel, Germany. 8. Center for Anatomy, Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, Berlin, Germany. 9. Institute of Pathology, University of Kiel, Kiel, Germany. 10. Department of General, Visceral and Transplantation Surgery, Centre of Surgery, University of Ulm, Ulm, Germany. 11. Centre for Cell Death, Cancer and Inflammation, University College London Cancer Institute, London, United Kingdom. 12. Division of Molecular Internal Medicine, Department of Internal Medicine II, University Hospital Würzburg, Würzburg, Germany. 13. Division of Molecular Oncology, Institute for Experimental Cancer Research, University of Kiel, Kiel, Germany. Electronic address: atrauzold@email.uni-kiel.de.
Abstract
BACKGROUND & AIMS: Tumor necrosis factor-related apoptosis inducing ligand (TRAIL-R1) (TNFRSF10A) and TRAIL-R2 (TNFRSF10B) on the plasma membrane bind ligands that activate apoptotic and other signaling pathways. Cancer cells also might have TRAIL-R2 in the cytoplasm or nucleus, although little is known about its activities in these locations. We investigated the functions of nuclear TRAIL-R2 in cancer cell lines. METHODS: Proteins that interact with TRAIL-R2 initially were identified in pancreatic cancer cells by immunoprecipitation, mass spectrometry, and immunofluorescence analyses. Findings were validated in colon, renal, lung, and breast cancer cells. Functions of TRAIL-R2 were determined from small interfering RNA knockdown, real-time polymerase chain reaction, Drosha-activity, microRNA array, proliferation, differentiation, and immunoblot experiments. We assessed the effects of TRAIL-R2 overexpression or knockdown in human pancreatic ductal adenocarcinoma (PDAC) cells and their ability to form tumors in mice. We also analyzed levels of TRAIL-R2 in sections of PDACs and non-neoplastic peritumoral ducts from patients. RESULTS: TRAIL-R2 was found to interact with the core microprocessor components Drosha and DGCR8 and the associated regulatory proteins p68, hnRNPA1, NF45, and NF90 in nuclei of PDAC and other tumor cells. Knockdown of TRAIL-R2 increased Drosha-mediated processing of the let-7 microRNA precursor primary let-7 (resulting in increased levels of mature let-7), reduced levels of the let-7 targets (LIN28B and HMGA2), and inhibited cell proliferation. PDAC tissues from patients had higher levels of nuclear TRAIL-R2 than non-neoplastic pancreatic tissue, which correlated with increased nuclear levels of HMGA2 and poor outcomes. Knockdown of TRAIL-R2 in PDAC cells slowed their growth as orthotopic tumors in mice. Reduced nuclear levels of TRAIL-R2 in cultured pancreatic epithelial cells promoted their differentiation. CONCLUSIONS: Nuclear TRAIL-R2 inhibits maturation of the microRNA let-7 in pancreatic cancer cell lines and increases their proliferation. Pancreatic tumor samples have increased levels of nuclear TRAIL-R2, which correlate with poor outcome of patients. These findings indicate that in the nucleus, death receptors can function as tumor promoters and might be therapeutic targets.
BACKGROUND & AIMS:Tumornecrosis factor-related apoptosis inducing ligand (TRAIL-R1) (TNFRSF10A) and TRAIL-R2 (TNFRSF10B) on the plasma membrane bind ligands that activate apoptotic and other signaling pathways. Cancer cells also might have TRAIL-R2 in the cytoplasm or nucleus, although little is known about its activities in these locations. We investigated the functions of nuclear TRAIL-R2 in cancer cell lines. METHODS: Proteins that interact with TRAIL-R2 initially were identified in pancreatic cancer cells by immunoprecipitation, mass spectrometry, and immunofluorescence analyses. Findings were validated in colon, renal, lung, and breast cancer cells. Functions of TRAIL-R2 were determined from small interfering RNA knockdown, real-time polymerase chain reaction, Drosha-activity, microRNA array, proliferation, differentiation, and immunoblot experiments. We assessed the effects of TRAIL-R2 overexpression or knockdown in humanpancreatic ductal adenocarcinoma (PDAC) cells and their ability to form tumors in mice. We also analyzed levels of TRAIL-R2 in sections of PDACs and non-neoplastic peritumoral ducts from patients. RESULTS:TRAIL-R2 was found to interact with the core microprocessor components Drosha and DGCR8 and the associated regulatory proteins p68, hnRNPA1, NF45, and NF90 in nuclei of PDAC and other tumor cells. Knockdown of TRAIL-R2 increased Drosha-mediated processing of the let-7 microRNA precursor primary let-7 (resulting in increased levels of mature let-7), reduced levels of the let-7 targets (LIN28B and HMGA2), and inhibited cell proliferation. PDAC tissues from patients had higher levels of nuclear TRAIL-R2 than non-neoplastic pancreatic tissue, which correlated with increased nuclear levels of HMGA2 and poor outcomes. Knockdown of TRAIL-R2 in PDAC cells slowed their growth as orthotopic tumors in mice. Reduced nuclear levels of TRAIL-R2 in cultured pancreatic epithelial cells promoted their differentiation. CONCLUSIONS: Nuclear TRAIL-R2 inhibits maturation of the microRNA let-7 in pancreatic cancer cell lines and increases their proliferation. Pancreatic tumor samples have increased levels of nuclear TRAIL-R2, which correlate with poor outcome of patients. These findings indicate that in the nucleus, death receptors can function as tumor promoters and might be therapeutic targets.
Authors: Cristiana Pistol Tanase; Ana Iulia Neagu; Laura Georgiana Necula; Cristina Mambet; Ana-Maria Enciu; Bogdan Calenic; Maria Linda Cruceru; Radu Albulescu Journal: World J Gastroenterol Date: 2014-08-21 Impact factor: 5.742
Authors: Jia Ming Liu; Xin Hua Long; Guo Mei Zhang; Yang Zhou; Xuan Yin Chen; Shan Hu Huang; Zhi Li Liu; Zhi Hong Zhang Journal: Int J Clin Exp Pathol Date: 2014-07-15