@article{MurtiFenderGlatzleetal.2023, author = {Murti, Krisna and Fender, Hendrik and Glatzle, Carolin and Wismer, Rhoda and Sampere-Birlanga, Salvador and Wild, Vanessa and Muhammad, Khalid and Rosenwald, Andreas and Serfling, Edgar and Avots, Andris}, title = {Calcineurin-independent NFATc1 signaling is essential for survival of Burkitt lymphoma cells}, series = {Frontiers in Oncology}, volume = {13}, journal = {Frontiers in Oncology}, doi = {10.3389/fonc.2023.1205788}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-323103}, year = {2023}, abstract = {In Burkitt lymphoma (BL), a tumor of germinal center B cells, the pro-apoptotic properties of MYC are controlled by tonic B cell receptor (BCR) signals. Since BL cells do not exhibit constitutive NF-κB activity, we hypothesized that anti-apoptotic NFATc1 proteins provide a major transcriptional survival signal in BL. Here we show that post-transcriptional mechanisms are responsible for the calcineurin (CN) independent constitutive nuclear over-expression of NFATc1 in BL and Eµ-MYC - induced B cell lymphomas (BCL). Conditional inactivation of the Nfatc1 gene in B cells of Eµ-MYC mice leads to apoptosis of BCL cells in vivo and ex vivo. Inhibition of BCR/SYK/BTK/PI3K signals in BL cells results in cytosolic re-location of NFATc1 and apoptosis. Therefore, NFATc1 activity is an integrated part of tonic BCR signaling and an alternative target for therapeutic intervention in BL.}, language = {en} } @article{HeuserGototPiotrowskietal.2017, author = {Heuser, Christoph and Gotot, Janine and Piotrowski, Eveline Christina and Philipp, Marie-Sophie and Courr{\`e}ges, Christina Johanna Felicia and Otte, Martin Sylvester and Guo, Linlin and Schmid-Burgk, Jonathan Leo and Hornung, Veit and Heine, Annkristin and Knolle, Percy Alexander and Garbi, Natalio and Serfling, Edgar and Evaristo, C{\´e}sar and Thaiss, Friedrich and Kurts, Christian}, title = {Prolonged IKK\(\beta\) Inhibition Improves Ongoing CTL Antitumor Responses by Incapacitating Regulatory T Cells}, series = {Cell Reports}, volume = {21}, journal = {Cell Reports}, number = {3}, doi = {10.1016/j.celrep.2017.09.082}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-173643}, pages = {578-586}, year = {2017}, abstract = {Regulatory T cells (Tregs) prevent autoimmunity but limit antitumor immunity. The canonical NF-\(\kappa\)B signaling pathway both activates immunity and promotes thymic Treg development. Here, we report that mature Tregs continue to require NF-\(\kappa\)B signaling through I\(\kappa\)B-kinase \(\beta\) (IKK\(\beta\)) after thymic egress. Mice lacking IKK\(\beta\) in mature Tregs developed scurfy-like immunopathology due to death of peripheral FoxP3\(^+\) Tregs. Also, pharmacological IKK\(\beta\) inhibition reduced Treg numbers in the circulation by ~50\% and downregulated FoxP3 and CD25 expression and STAT5 phosphorylation. In contrast, activated cytotoxic T lymphocytes (CTLs) were resistant to IKK\(\beta\) inhibition because other pathways, in particular nuclear factor of activated T cells (NFATc1) signaling, sustained their survival and expansion. In a melanoma mouse model, IKK\(\beta\) inhibition after CTL cross-priming improved the antitumor response and delayed tumor growth. In conclusion, prolonged IKK\(\beta\) inhibition decimates circulating Tregs and improves CTL responses when commenced after tumor vaccination, indicating that IKK\(\beta\) represents a druggable checkpoint.}, language = {en} } @article{EffenbergerBommertKunzetal.2017, author = {Effenberger, Madlen and Bommert, Kathryn S. and Kunz, Viktoria and Kruk, Jessica and Leich, Ellen and Rudelius, Martina and Bargou, Ralf and Bommert, Kurt}, title = {Glutaminase inhibition in multiple myeloma induces apoptosis via MYC degradation}, series = {Oncotarget}, volume = {8}, journal = {Oncotarget}, number = {49}, doi = {10.18632/oncotarget.20691}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170168}, pages = {85858-85867}, year = {2017}, abstract = {Multiple Myeloma (MM) is an incurable hematological malignancy affecting millions of people worldwide. As in all tumor cells both glucose and more recently glutamine have been identified as important for MM cellular metabolism, however there is some dispute as to the role of glutamine in MM cell survival. Here we show that the small molecule inhibitor compound 968 effectively inhibits glutaminase and that this inhibition induces apoptosis in both human multiple myeloma cell lines (HMCLs) and primary patient material. The HMCL U266 which does not express MYC was insensitive to both glutamine removal and compound 968, but ectopic expression of MYC imparted sensitivity. Finally, we show that glutamine depletion is reflected by rapid loss of MYC protein which is independent of MYC transcription and post translational modifications. However, MYC loss is dependent on proteasomal activity, and this loss was paralleled by an equally rapid induction of apoptosis. These findings are in contrast to those of glucose depletion which largely affected rates of proliferation in HMCLs, but had no effects on either MYC expression or viability. Therefore, inhibition of glutaminolysis is effective at inducing apoptosis and thus serves as a possible therapeutic target in MM.}, language = {en} } @article{ShiKuaiLeietal.2016, author = {Shi, Yaoyao and Kuai, Yue and Lei, Lizhen and Weng, Yuanyuan and Berberich-Siebelt, Friederike and Zhang, Xinxia and Wang, Jinjie and Zhou, Yuan and Jiang, Xin and Ren, Guoping and Pan, Hongyang and Mao, Zhengrong and Zhou, Ren}, title = {The feedback loop of LITAF and BCL6 is involved in regulating apoptosis in B cell non-Hodgkin's-lymphoma}, series = {Oncotarget}, volume = {7}, journal = {Oncotarget}, number = {47}, doi = {10.18632/oncotarget.12680}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166500}, pages = {77444-77456}, year = {2016}, abstract = {Dysregulation of the apoptotic pathway is widely recognized as a key step in lymphomagenesis. Notably, LITAF was initially identified as a p53-inducible gene, subsequently implicated as a tumor suppressor. Our previous study also showed LITAF to be methylated in 89.5\% B-NHL samples. Conversely, deregulated expression of BCL6 is a pathogenic event in many lymphomas. Interestingly, our study found an oppositional expression of LITAF and BCL6 in B-NHL. In addition, LITAF was recently identified as a novel target gene of BCL6. Therefore, we sought to explore the feedback loop between LITAF and BCL6 in B-NHL. Here, our data for the first time show that LITAF can repress expression of BCL6 by binding to Region A (-87 to +65) containing a putative LITAF-binding motif (CTCCC) within the BCL6 promoter. Furthermore, the regulation of BCL6 targets (PRDM1 or c-Myc) by LITAF may be associated with B-cell differentiation. Results also demonstrate that ectopic expression of LITAF induces cell apoptosis, activated by releasing cytochrome c, cleaving PARP and caspase 3 in B-NHL cells whereas knockdown of LITAF robustly protected cells from apoptosis. Interestingly, BCL6, in turn, could reverse cell apoptosis mediated by LITAF. Collectively, our findings provide a novel apoptotic regulatory pathway in which LITAF, as a transcription factor, inhibits the expression of BCL6, which leads to activation of the intrinsic mitochondrial pathway and tumor apoptosis. Our study is expected to provide a possible biomarker as well as a target for clinical therapies to promote tumor cell apoptosis.}, language = {en} } @article{RascheDuellMorgneretal.2013, author = {Rasche, Leo and Duell, Johannes and Morgner, Charlotte and Chatterjee, Manik and Hensel, Frank and Rosenwald, Andreas and Einsele, Hermann and Topp, Max S. and Br{\"a}ndlein, Stephanie}, title = {The Natural Human IgM Antibody PAT-SM6 Induces Apoptosis in Primary Human Multiple Myeloma Cells by Targeting Heat Shock Protein GRP78}, series = {PLoS ONE}, volume = {8}, journal = {PLoS ONE}, number = {5}, doi = {10.1371/journal.pone.0063414}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130125}, pages = {e63414}, year = {2013}, abstract = {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.}, language = {en} } @article{HuangBelharazemLietal.2013, author = {Huang, Bei and Belharazem, Djeda and Li, Li and Kneitz, Susanne and Schnabel, Philipp A. and Rieker, Ralf J. and K{\"o}rner, Daniel and Nix, Wilfried and Schalke, Berthold and M{\"u}ller-Hermelink, Hans Konrad and Ott, German and Rosenwald, Andreas and Str{\"o}bel, Philipp and Marx, Alexander}, title = {Anti-apoptotic signature in thymic squamous cell carcinomas - functional relevance of anti-apoptotic BIRC3 expression in the thymic carcinoma cell line 1889c}, series = {Frontiers in Oncology}, volume = {3}, journal = {Frontiers in Oncology}, number = {316}, doi = {10.3389/fonc.2013.00316}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132214}, year = {2013}, abstract = {The molecular pathogenesis of thymomas and thymic arcinomas (TCs) is poorly understood and results of adjuvant therapy are unsatisfactory in case of metastatic disease and tumor recurrence. For these clinical settings, novel therapeutic strategies are urgently needed. Recently, limited sequencing efforts revealed that a broad spectrum of genes that play key roles in various common cancers are rarely affected in thymomas and TCs, suggesting that other oncogenic principles might be important.This made us re-analyze historic expression data obtained in a spectrumof thymomas and thymic squamous cell carcinomas (TSCCs) with a custom-made cDNA microarray. By cluster analysis, different anti-apoptotic signatures were detected in type B3 thymoma and TSCC, including overexpression of BIRC3 in TSCCs. This was confirmed by qRT-PCR in the original and an independent validation set of tumors. In contrast to several other cancer cell lines, the BIRC3-positive TSCC cell line, 1889c showed spontaneous apoptosis after BIRC3 knock-down. Targeting apoptosis genes is worth testing as therapeutic principle in TSCC.}, language = {en} } @article{SchlerethHeylKrampitzetal.2013, author = {Schlereth, Katharina and Heyl, Charlotte and Krampitz, Anna-Maria and Mernberger, Marco and Finkernagel, Florian and Scharfe, Maren and Jarek, Michael and Leich, Ellen and Rosenwald, Andreas and Stiewe, Thorsten}, title = {Characterization of the p53 Cistrome - DNA Binding Cooperativity Dissects p53's Tumor Suppressor Functions}, series = {PLOS Genetics}, volume = {9}, journal = {PLOS Genetics}, number = {8}, issn = {1553-7404}, doi = {10.1371/journal.pgen.1003726}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-127579}, pages = {e1003726}, year = {2013}, abstract = {p53 protects us from cancer by transcriptionally regulating tumor suppressive programs designed to either prevent the development or clonal expansion of malignant cells. How p53 selects target genes in the genome in a context-and tissue-specific manner remains largely obscure. There is growing evidence that the ability of p53 to bind DNA in a cooperative manner prominently influences target gene selection with activation of the apoptosis program being completely dependent on DNA binding cooperativity. Here, we used ChIP-seq to comprehensively profile the cistrome of p53 mutants with reduced or increased cooperativity. The analysis highlighted a particular relevance of cooperativity for extending the p53 cistrome to non-canonical binding sequences characterized by deletions, spacer insertions and base mismatches. Furthermore, it revealed a striking functional separation of the cistrome on the basis of cooperativity; with low cooperativity genes being significantly enriched for cell cycle and high cooperativity genes for apoptotic functions. Importantly, expression of high but not low cooperativity genes was correlated with superior survival in breast cancer patients. Interestingly, in contrast to most p53-activated genes, p53-repressed genes did not commonly contain p53 binding elements. Nevertheless, both the degree of gene activation and repression were cooperativity-dependent, suggesting that p53-mediated gene repression is largely indirect and mediated by cooperativity-dependently transactivated gene products such as CDKN1A, E2F7 and non-coding RNAs. Since both activation of apoptosis genes with non-canonical response elements and repression of pro-survival genes are crucial for p53's apoptotic activity, the cistrome analysis comprehensively explains why p53-induced apoptosis, but not cell cycle arrest, strongly depends on the intermolecular cooperation of p53 molecules as a possible safeguard mechanism protecting from accidental cell killing.}, language = {en} }