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Geismann C.,University of Kiel | Grohmann F.,University of Kiel | Sebens S.,2Institute for Experimental Medicine | Wirths G.,University of Kiel | And 11 more authors.
Cell Death and Disease | Year: 2014

Pancreatic ductal adenocarcinoma (PDAC) represents one of the deadliest malignancies with an overall life expectancy of 6 months despite current therapies. NF-?B signalling has been shown to be critical for this profound cell-autonomous resistance against chemotherapeutic drugs and death receptor-induced apoptosis, but little is known about the role of the c-Rel subunit in solid cancer and PDAC apoptosis control. In the present study, by analysis of genome-wide patterns of c-Rel-dependent gene expression, we were able to establish c-Rel as a critical regulator of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in PDAC. TRAIL-resistant cells exhibited a strong TRAIL-inducible NF-?B activity, whereas TRAIL-sensitive cells displayed only a small increase in NF-?B-binding activity. Transfection with siRNA against c-Rel sensitized the TRAIL-resistant cells in a manner comparable to siRNA targeting the p65/RelA subunit. Gel-shift analysis revealed that c-Rel is part of the TRAIL-inducible NF-?B complex in PDAC. Array analysis identified NFATc2 as a c-Rel target gene among the 12 strongest TRAIL-inducible genes in apoptosis-resistant cells. In line, siRNA targeting c-Rel strongly reduced TRAIL-induced NFATc2 activity in TRAIL-resistant PDAC cells. Furthermore, siRNA targeting NFATc2 sensitized these PDAC cells against TRAILinduced apoptosis. Finally, TRAIL-induced expression of COX-2 was diminished through siRNA targeting c-Rel or NFATc2 and pharmacologic inhibition of COX-2 with celecoxib or siRNA targeting COX-2, enhanced TRAIL apoptosis. In conclusion, we were able to delineate a novel c-Rel-, NFATc2- and COX-2-dependent antiapoptotic signalling pathway in PDAC with broad clinical implications for pharmaceutical intervention strategies. © 2014 Macmillan Publishers Limited. All rights reserved.


PubMed | University of Tübingen, Institute for Experimental Cancer Research, Institute for Experimental Medicine, Institute of Clinical Molecular Biology and 2 more.
Type: | Journal: Cell death & disease | Year: 2014

Pancreatic ductal adenocarcinoma (PDAC) represents one of the deadliest malignancies with an overall life expectancy of 6 months despite current therapies. NF-B signalling has been shown to be critical for this profound cell-autonomous resistance against chemotherapeutic drugs and death receptor-induced apoptosis, but little is known about the role of the c-Rel subunit in solid cancer and PDAC apoptosis control. In the present study, by analysis of genome-wide patterns of c-Rel-dependent gene expression, we were able to establish c-Rel as a critical regulator of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in PDAC. TRAIL-resistant cells exhibited a strong TRAIL-inducible NF-B activity, whereas TRAIL-sensitive cells displayed only a small increase in NF-B-binding activity. Transfection with siRNA against c-Rel sensitized the TRAIL-resistant cells in a manner comparable to siRNA targeting the p65/RelA subunit. Gel-shift analysis revealed that c-Rel is part of the TRAIL-inducible NF-B complex in PDAC. Array analysis identified NFATc2 as a c-Rel target gene among the 12 strongest TRAIL-inducible genes in apoptosis-resistant cells. In line, siRNA targeting c-Rel strongly reduced TRAIL-induced NFATc2 activity in TRAIL-resistant PDAC cells. Furthermore, siRNA targeting NFATc2 sensitized these PDAC cells against TRAIL-induced apoptosis. Finally, TRAIL-induced expression of COX-2 was diminished through siRNA targeting c-Rel or NFATc2 and pharmacologic inhibition of COX-2 with celecoxib or siRNA targeting COX-2, enhanced TRAIL apoptosis. In conclusion, we were able to delineate a novel c-Rel-, NFATc2- and COX-2-dependent antiapoptotic signalling pathway in PDAC with broad clinical implications for pharmaceutical intervention strategies.


PubMed | Albert Ludwigs University of Freiburg, Institute for Experimental Cancer Research, Leiden University, University of Southampton and 2 more.
Type: Journal Article | Journal: Blood | Year: 2015

B-cell antigen receptor (BCR) expression is a key feature of most B-cell lymphomas, but the mechanisms of BCR signal induction and the involvement of autoantigen recognition remain unclear. In follicular lymphoma (FL) B cells, BCR expression is retained despite a chromosomal translocation that links the antiapoptotic gene BCL2 to the regulatory elements of immunoglobulin genes, thereby disrupting 1 heavy-chain allele. A remarkable feature of FL-BCRs is the acquisition of potential N-glycosylation sites during somatic hypermutation. The introduced glycans carry mannose termini, which create potential novel binding sites for mannose-specific lectins. Here, we investigated the effect of N-linked variable-region glycosylation for BCR interaction with cognate antigen and with lectins of different origins. N-glycans were found to severely impair BCR specificity and affinity to the initial cognate antigen. In addition, we found that lectins from Pseudomonas aeruginosa and Burkholderia cenocepacia bind and stimulate FL cells. Human exposure to these bacteria can occur by contact with soil and water. In addition, they represent opportunistic pathogens in susceptible hosts. Understanding the role of bacterial lectins might elucidate the pathogenesis of FL and establish novel therapeutic approaches.


Lascano V.,University of Amsterdam | Zabalegui L.F.,Institute Of Genetique Moleculaire Of Montpellier | Zabalegui L.F.,Montpellier University | Cameron K.,University of Amsterdam | And 12 more authors.
Cell Death and Differentiation | Year: 2012

The tumor necrosis factor (TNF) family member APRIL (A proliferation inducing ligand) is a disease promoter in B-cell malignancies. APRIL has also been associated with a wide range of solid malignancies, including colorectal cancer (CRC). As evidence for a supportive role of APRIL in solid tumor formation was still lacking, we studied the involvement of APRIL in CRC. We observed that ectopic APRIL expression exacerbates the number and size of adenomas in ApcMin mice and in a mouse model for colitis-associated colon carcinogenesis. Furthermore, knockdown of APRIL in primary spheroid cultures of colon cancer cells and both mouse and human CRC cell lines reduced tumor clonogenicity and in vivo outgrowth. Taken together, our data therefore indicate that both tumor-derived APRIL and APRIL produced by non-tumor cells is supportive in colorectal tumorigenesis. © 2012 Macmillan Publishers Limited. All rights reserved.


Schafer H.,Laboratory of Molecular Gastroenterology and Hepatology | Geismann C.,Laboratory of Molecular Gastroenterology and Hepatology | Heneweer C.,Clinic for Diagnostic Radiology | Egberts J.-H.,Clinic of General Surgery and Thoracic Surgery | And 8 more authors.
Carcinogenesis | Year: 2012

Pancreatic ductal adenocarcinoma (PDAC) and chronic pancreatitis, representing one risk factor for PDAC, are characterized by a marked desmoplasia enriched of pancreatic myofibroblasts (PMFs). Thus, PMFs are thought to essentially promote pancreatic tumorigenesis. We recently demonstrated that the adhesion molecule L1CAM is involved in epithelial-mesenchymal transition of PMF-cocultured H6c7 human ductal epithelial cells and that L1CAM is expressed already in ductal structures of chronic pancreatitis with even higher elevation in primary tumors and metastases of PDAC patients. This study aimed at investigating whether PMFs and L1CAM drive malignant transformation of pancreatic ductal epithelial cells by enhancing their tumorigenic potential. Cell culture experiments demonstrated that in the presence of PMFs, H6c7 cells exhibit a profound resistance against death ligand-induced apoptosis. This apoptosis protection was similarly observed in H6c7 cells stably overexpressing L1CAM. Intrapancreatic inoculation of H6c7 cells together with PMFs (H6c7co) resulted in tumor formation in 7/8 and liver metastases in 6/8 severe combined immunodeficiency (SCID) mice, whereas no tumors and metastases were detectable after inoculation of H6c7 cells alone. Likewise, tumor outgrowth and metastases resulted from inoculation of L1CAM-overexpressing H6c7 cells in 5/7 and 3/7 SCID mice, respectively, but not from inoculation of mock-transfected H6c7 cells. Treatment of H6c7co tumor-bearing mice with the L1CAM antibody L1-9.3/2a inhibited tumor formation and liver metastasis in 100 and 50%, respectively, of the treated animals. Overall, these data provide new insights into the mechanisms of how PMFs and L1CAM contribute to malignant transformation of pancreatic ductal epithelial cells in early stages of pancreatic tumorigenesis. © The Author 2011. Published by Oxford University Press. All rights reserved.


Meincke M.,University of Kiel | Tiwari S.,Institute for Experimental Cancer Research | Hattermann K.,University of Kiel | Kalthoff H.,Institute for Experimental Cancer Research | Mentlein R.,University of Kiel
Clinical and Experimental Metastasis | Year: 2011

The chemokine CXCL12/SDF-1 and its receptors CXCR4 and CXCR7 play a major role in tumor invasion, proliferation and metastasis. Since both receptors are overexpressed on distinct tumor cells and on the tumor vasculature, we evaluated their potential as targets for detection of cancers by molecular imaging. We synthesized conjugates of CXCL12 and the near-infrared (NIR) fluorescent dye IRDye ®800CW, tested their selectivity, sensitivity and biological activity in vitro and their feasibility to visualize tumors in vivo. Purified CXCL12-conjugates detected in vitro as low as 500 A764 human glioma cells or MCF-7 breast cancer cells that express CXCR7 alone or together with CXCR4. Binding was time- and concentration-dependent, and the label could be competitively displaced by the native peptide. Control conjugates with bovine serum albumin or lactalbumin failed to label the cells. In mice, the conjugate distributed rapidly. After 1-92 h, subcutaneous tumors of human MCF-7 and A764 cells in immunodeficient mice were detected with high sensitivity. Background was observed in particular in liver within the first 24 h, but also skull and hind limbs yielded some background. Overall, fluorescent CXCL12-conjugates are sensitive and selective probes to detect solid and metastatic tumors by targeting tumor cells and tumor vasculature. © 2011 The Author(s).


Scholer N.,Institute for Experimental Cancer Research | Langer C.,University of Ulm | Dohner H.,University of Ulm | Buske C.,Institute for Experimental Cancer Research | And 2 more authors.
Experimental Hematology | Year: 2010

Recently, expression patterns of microRNAs in body fluids underscored their potential as noninvasive biomarkers for various diseases. Here we summarize the current works describing microRNAs in blood cells or serum as biomarkers and the applied methodologies of small RNA purification and detection. Future challenges and the required research relating to optimization of working with microRNAs in serum will also be discussed. © 2010 ISEH - Society for Hematology and Stem Cells.


Schafer H.,Laboratory of Molecular Gastroenterology and Hepatology | Dieckmann C.,Laboratory of Molecular Gastroenterology and Hepatology | Korniienko O.,Institute for Experimental Cancer Research | Moldenhauer G.,German Cancer Research Center | And 6 more authors.
Cancer Letters | Year: 2012

The adhesion molecule L1CAM (CD171) accounts for enhanced motility, invasiveness and chemoresistance of tumor cells and represents a novel marker for various tumor entities including pancreatic and ovarian carcinoma. Recently, we showed that L1CAM inhibition increases the apoptotic response of tumor cells towards cytostatic drugs pointing to the potential of L1CAM to serve as a chemosensitizer in anti-cancer therapy. Thus, the present study evaluated the therapeutic potential of combined treatment with L1CAM antibodies and chemotherapeutic drugs in pancreatic and ovarian carcinoma model systems. in vivo. Two L1CAM-specific antibodies (L1-14.10 and L1-9.3/2a) exhibiting high binding affinity to the L1CAM expressing pancreatic adenocarcinoma cell line Colo357 and the ovarian carcinoma cell line SKOV3ip were used for treatment. The combined therapy of SCID mice with either L1CAM antibody and gemcitabine and paclitaxel, respectively, reduced the growth of subcutaneously grown Colo357 or SKOV3ip tumors more efficiently than treatment with the cytostatic drug alone or in combination with control IgG. This was accompanied by an increased number of apoptotic tumor cells along with an elevated procaspase-8 expression. Furthermore, a lowered activation of NF-κB along with a reduced expression of VEGF and a diminished number of CD31-positive blood vessels were observed in tumors after combined therapy compared to control treatments, while the infiltration of F4/80-positive macrophages increased. Overall, these data provide new insights into the mechanism of the anti-cancer activity of L1CAM-blocking antibodies. in vivo and support the suitability of L1CAM as a target for chemosensitization and of L1CAM-interfering antibodies as an appropriate tool to increase the therapeutic response of pancreatic and ovarian carcinoma. © 2011 Elsevier Ireland Ltd.


Kumar M.,Institute of Molecular Medicine | Kumar M.,Heinrich Pette Institute | Witt B.,Heinrich Pette Institute | Knippschild U.,University of Ulm | And 11 more authors.
International Journal of Cancer | Year: 2013

Telomerase is activated in the majority of invasive breast cancers, but the time point of telomerase activation during mammary carcinogenesis is not clear. We have recently presented a transgenic mouse model to study human telomerase reverse transcriptase (TERT) gene expression in vivo (hTERTp-lacZ). In the present study, hTERTp-lacZxWAP-T bitransgenic mice were generated to analyze the mechanisms responsible for human and mouse TERT upregulation during tumor progression in vivo. We found that telomerase activity and TERT expression were consistently upregulated in SV40-induced invasive mammary tumors compared to normal and hyperplastic tissues and ductal carcinoma in situ (DCIS). Human and mouse TERT genes are regulated similarly in the breast tissue, involving the CEBP transcription factors. Loss of CEBP-α and induction of CEBP-β expression correlated well with the activation of TERT expression in mouse mammary tumors. Transfection of CEBP-α into human or murine cells resulted in TERT repression, whereas knockdown of CEBP-α in primary human mammary epithelial cells resulted in reactivation of endogenous TERT expression and telomerase activity. Conversely, ectopic expression of CEBP-β activated endogenous TERT gene expression. Moreover, ChIP and EMSA experiments revealed binding of CEBP-α and CEBP-β to human TERT-promoter. This is the first evidence indicating that CEBP-α and CEBP-β are involved in TERT gene regulation during carcinogenesis. What's new? Telomerase activity has been described in invasive breast cancer, but little is known about its regulation in this disease. In this study, telomerase activity and expression of the telomerase catalytic subunit TERT were found to be strongly induced in invasive but not non-invasive mammary carcinomas of mice. In addition, CEBP transcription factors were observed bound to the TERT promoter, suggesting that they are involved in TERT regulation and carcinogenesis. The findings could have implications for the treatment of breast cancer. Copyright © 2012 UICC.


PubMed | Institute for Experimental Cancer Research
Type: | Journal: Methods in molecular medicine | Year: 2011

Cellular transformation does not necessarily require the expression of proteins with neoantigenic properties, and for this reason, immunosurveillance does not register all tumor cells. They frequently express potentially immunogenic components, but are able to escape elimination by immune mechanisms. One explanation for this escape is poor antigen presentation by the tumor cells, resulting in little or no measurable antitumor immunity in immunocompetent hosts. T cells remain naive or even become anergic to the tumor cells. Reasons for the deficient antigen presentation by the tumor cells include the reduced or absent expression of major histocompatibility complex (MHC) molecules and the absence of tumor antigens in the groove of class I or class II MHC molecules as a consequence of defective protein processing. Other reasons are the absence or inadequate levels of expression of adhesion molecules, the absence or inadequate levels of costimulatory molecules or the expression of lymphocyte suppressive cytokines like transforming growth factor (TGF-) or interleukin 10 (IL-10) by tumor cells (1-5).

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