@article{SirtlKnollDieuThuyetal.2018, author = {Sirtl, Simon and Knoll, Gertrud and Dieu Thuy, Trinh and Lang, Isabell and Siegmund, Daniela and Gross, Stefanie and Schuler-Thurner, Beatrice and Neubert, Patrick and Jantsch, Jonathan and Wajant, Harald and Ehrenschwender, Martin}, title = {Hypertonicity-enforced BCL-2 addiction unleashes the cytotoxic potential of death receptors}, series = {Oncogene}, volume = {37}, journal = {Oncogene}, doi = {10.1038/s41388-018-0265-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-238327}, pages = {4122-4136}, year = {2018}, abstract = {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.}, language = {en} } @article{KuckaLangZhangetal.2021, author = {Kucka, Kirstin and Lang, Isabell and Zhang, Tengyu and Siegmund, Daniela and Medler, Juliane and Wajant, Harald}, title = {Membrane lymphotoxin-α\(_2\)β is a novel tumor necrosis factor (TNF) receptor 2 (TNFR2) agonist}, series = {Cell Death \& Disease}, volume = {12}, journal = {Cell Death \& Disease}, number = {4}, doi = {10.1038/s41419-021-03633-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-260077}, pages = {360}, year = {2021}, abstract = {In the early 1990s, it has been described that LTα and LTβ form LTα\(_2\)β and LTαβ\(_2\) heterotrimers, which bind to TNFR1 and LTβR, respectively. Afterwards, the LTαβ\(_2\)-LTβR system has been intensively studied while the LTα\(_2\)β-TNFR1 interaction has been ignored to date, presumably due to the fact that at the time of identification of the LTα\(_2\)β-TNFR1 interaction one knew already two ligands for TNFR1, namely TNF and LTα. Here, we show that LTα\(_2\)β interacts not only with TNFR1 but also with TNFR2. We furthermore demonstrate that membrane-bound LTα\(_2\)β (memLTα\(_2\)β), despite its asymmetric structure, stimulates TNFR1 and TNFR2 signaling. Not surprising in view of its ability to interact with TNFR2, LTα\(_2\)β is inhibited by Etanercept, which is approved for the treatment of rheumatoid arthritis and also inhibits TNF and LTα.}, language = {en} } @article{CarmonaAranaSeherNeumannetal.2014, author = {Carmona Arana, Jos{\´e} Antonio and Seher, Axel and Neumann, Manfred and Lang, Isabell and Siegmund, Daniela and Wajant, Harald}, title = {TNF Receptor-Associated Factor 1 is a Major Target of Soluble TWEAK}, series = {Frontiers in Immunology}, volume = {5}, journal = {Frontiers in Immunology}, number = {63}, issn = {1664-3224}, doi = {10.3389/fimmu.2014.00063}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120620}, year = {2014}, abstract = {Soluble tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK), in contrast to membrane TWEAK and TNF, is only a weak activator of the classical NFκB pathway. We observed that soluble TWEAK was regularly more potent than TNF with respect to the induction of TNF receptor-associated factor 1 (TRAF1), a NFκB-controlled signaling protein involved in the regulation of inflammatory signaling pathways. TNF-induced TRAF1 expression was efficiently blocked by inhibition of the classical NFκB pathway using the IKK2 inhibitor, TPCA1. In contrast, in some cell lines, TWEAK-induced TRAF1 production was only partly inhibited by TPCA1. The NEDD8-activating enzyme inhibitor MLN4924, however, which inhibits classical and alternative NFκB signaling, blocked TNF- and TWEAK-induced TRAF1 expression. This suggests that TRAF1 induction by soluble TWEAK is based on the cooperative activity of the two NFκB signaling pathways. We have previously shown that oligomerization of soluble TWEAK results in ligand complexes with membrane TWEAK-like activity. Oligomerization of soluble TWEAK showed no effect on the dose response of TRAF1 induction, but potentiated the ability of soluble TWEAK to trigger production of the classical NFκB-regulated cytokine IL8. Transfectants expressing soluble TWEAK and membrane TWEAK showed similar induction of TRAF1 while only the membrane TWEAK expressing cells robustly stimulated IL8 production. These data indicate that soluble TWEAK may efficiently induce a distinct subset of the membrane TWEAK-targeted genes and argue again for a crucial role of classical NFκB pathway-independent signaling in TWEAK-induced TRAF1 expression. Other TWEAK targets, which can be equally well induced by soluble and membrane TWEAK, remain to be identified and the relevance of the ability of soluble TWEAK to induce such a distinct subset of membrane TWEAK-targeted genes for TWEAK biology will have to be clarified in future studies.}, language = {en} }