TY - JOUR A1 - Effenberger, Madlen A1 - Bommert, Kathryn S. A1 - Kunz, Viktoria A1 - Kruk, Jessica A1 - Leich, Ellen A1 - Rudelius, Martina A1 - Bargou, Ralf A1 - Bommert, Kurt T1 - Glutaminase inhibition in multiple myeloma induces apoptosis via MYC degradation JF - Oncotarget N2 - 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. KW - Multiple Myeloma KW - glutaminase inhibition KW - apoptosis KW - MYC Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170168 VL - 8 IS - 49 ER - TY - JOUR A1 - Lagler, Charlotte A1 - El-Mesery, Mohamed A1 - Kübler, Alexander Christian A1 - Müller-Richter, Urs Dietmar Achim A1 - Stühmer, Thorsten A1 - Nickel, Joachim A1 - Müller, Thomas Dieter A1 - Wajant, Harald A1 - Seher, Axel T1 - The anti-myeloma activity of bone morphogenetic protein 2 predominantly relies on the induction of growth arrest and is apoptosis-independent JF - PLoS ONE N2 - Multiple myeloma (MM), a malignancy of the bone marrow, is characterized by a pathological increase in antibody-producing plasma cells and an increase in immunoglobulins (plasmacytosis). In recent years, bone morphogenetic proteins (BMPs) have been reported to be activators of apoptotic cell death in neoplastic B cells in MM. Here, we use bone morphogenetic protein 2 (BMP2) to show that the "apoptotic" effect of BMPs on human neoplastic B cells is dominated by anti-proliferative activities and cell cycle arrest and is apoptosis-independent. The anti-proliferative effect of BMP2 was analysed in the human cell lines KMS12-BM and L363 using WST-1 and a Coulter counter and was confirmed using CytoTox assays with established inhibitors of programmed cell death (zVAD-fmk and necrostatin-1). Furthermore, apoptotic activity was compared in both cell lines employing western blot analysis for caspase 3 and 8 in cells treated with BMP2 and FasL. Additionally, expression profiles of marker genes of different cell death pathways were analysed in both cell lines after stimulation with BMP2 for 48h using an RT-PCR-based array. In our experiments we observed that there was rather no reduction in absolute cell number, but cells stopped proliferating following treatment with BMP2 instead. The time frame (48–72 h) after BMP2 treatment at which a reduction in cell number is detectable is too long to indicate a directly BMP2-triggered apoptosis. Moreover, in comparison to robust apoptosis induced by the approved apoptotic factor FasL, BMP2 only marginally induced cell death. Consistently, neither the known inhibitor of apoptotic cell death zVAD-fmk nor the necroptosis inhibitor necrostatin-1 was able to rescue myeloma cell growth in the presence of BMP2. KW - apoptosis KW - gene expression KW - necrotic cell death KW - multiple myeloma KW - cell metabolism KW - cell cycle and cell division KW - B cells Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-158993 VL - 12 IS - 10 ER - TY - JOUR A1 - Heuser, Christoph A1 - Gotot, Janine A1 - Piotrowski, Eveline Christina A1 - Philipp, Marie-Sophie A1 - Courrèges, Christina Johanna Felicia A1 - Otte, Martin Sylvester A1 - Guo, Linlin A1 - Schmid-Burgk, Jonathan Leo A1 - Hornung, Veit A1 - Heine, Annkristin A1 - Knolle, Percy Alexander A1 - Garbi, Natalio A1 - Serfling, Edgar A1 - Evaristo, César A1 - Thaiss, Friedrich A1 - Kurts, Christian T1 - Prolonged IKK\(\beta\) Inhibition Improves Ongoing CTL Antitumor Responses by Incapacitating Regulatory T Cells JF - Cell Reports N2 - 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. KW - medicine KW - regulatory T cells KW - NF-\(\kappa\)B pathway KW - tumor vaccination KW - checkpoint inhibition KW - cytotoxic T cells KW - cross-priming KW - apoptosis KW - tumor immunology KW - melanoma Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-173643 VL - 21 IS - 3 ER -