@article{MuellerSienerthDietzHoltzetal.2011,
  author    = {M{\"u}ller-Sienerth, Nicole and Dietz, Lena and Holtz, Philipp and Kapp, Markus and Grigoleit, G{\"o}tz Ulrich and Schmuck, Carsten and Wajant, Harald and Siegmund, Siegmund},
  title     = {SMAC Mimetic BV6 Induces Cell Death in Monocytes and Maturation of Monocyte-Derived Dendritic Cells},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-76106},
  year      = {2011},
  abstract  = {Background: Compounds mimicking the inhibitory effect of SMAC / DIABLO on X-linked inhibitor of apoptosis (XIAP) have been developed with the aim to achieve sensitization for apoptosis of tumor cells resistant due to deregulated XIAP expression. It turned out that SMAC mimetics also have complex effects on the NFkB system and TNF signaling. In view of the overwhelming importance of the NFkB transcription factors in the immune system, we analyzed here the effects of the SMAC mimetic BV6 on immune cells. Principal Findings: BV6 induced apoptotic and necrotic cell death in monocytes while T-cells, dendritic cells and macrophages were largely protected against BV6-induced cell death. In immature dendritic cells BV6 treatment resulted in moderate activation of the classical NFkB pathway, but it also diminished the stronger NFkB-inducing effect of TNF and CD40L. Despite its inhibitory effect on TNF- and CD40L signaling, BV6 was able to trigger maturation of immature DCs as indicated by upregulation of CD83, CD86 and IL12. Significance: The demonstrated effects of SMAC mimetics on immune cells may complicate the development of tumor therapeutic concepts based on these compounds but also arise the possibility to exploit them for the development of immune stimulatory therapies.},
  subject      = {Medizin},
  language  = {en}
}
@phdthesis{Siegmund2018,
  author    = {Siegmund, Constanze},
  title     = {Klinische Bedeutung der Regulation von L-Arginin sowie deren Derivate SDMA und ADMA im Akuten Nierenversagen - eine prospektive monozentrische Kohortenstudie (CASA-AKI Studie)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164300},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2018},
  abstract  = {Zusammenfassung Die vorliegende Arbeit untersucht die Regulation von SDMA/ADMA sowie L-Arginin im akuten Nierenversagen beim Menschen. Da SDMA ausschließlich renal eliminiert wird, ist der Fragestellung nachgegangen worden, ob SDMA als Marker der renalen Funktion herangezogen werden k{\"o}nnte. Des Weiteren wurde gepr{\"u}ft ob ein Zusammenhang von SDMA/ ADMA und L-Arginin mit der Mortalit{\"a}t besteht. Die Derivate von L-Arginin, Symmetrisches und asymmetrischen Dimethylarginin (SDMA/ ADMA) vermindern die NO Verf{\"u}gbarkeit, außerdem ist NO an der Gef{\"a}ßrelaxation beteiligt, dessen Abwesenheit f{\"o}rdert die Pl{\"a}ttchenaggregation und Inflammation. So k{\"o}nnte ein NO-Mangel {\"u}ber einen Anstieg von ADMA und SDMA eine endotheliale Dysfunktion bewirken und somit im akuten Nierenversagen das Mortalit{\"a}tsrisiko steigern. Die Hypothese war, dass SDMA analog zum chronischen Nierenversagen ein endogener Marker der renalen Funktion ist und gegebenenfalls Risikomarker f{\"u}r eine erh{\"o}hte Mortalit{\"a}t sein k{\"o}nnte. Hierf{\"u}r wurden Patienten mit der Diagnose „Akutes Nierenversagen" rekrutiert. Bei diesen wurde zu zwei Zeitpunkten Blutproben gewonnen. Die erste Blutentnahme erfolgte im akuten Nierenversagen. Eine zweite Blutentnahme zur Re-evaluation erfolgte wenn sich laborchemisch eine Besserung des Nierenversagens zeigte (Abfall des Serum-Creatinins >0.3mg/dl). Zudem wurden die Patienten 6 Monate nach Entlassung nochmals kontaktiert um das Gesamt{\"u}berleben zu ermitteln. L-Arginin und die Dimethylarginine wurden mit Nierenfunktionsparametern sowie weiteren Laborwerten, demographischen Daten sowie der Mortalit{\"a}t assoziiert. 120 Patienten (Durchschnittsalter 65±18 Jahre) mit der Diagnose eines akuten Nieren-versagens wurden in die Studie eingeschlossen. Definitionsgem{\"a}ß waren zum Zeitpunkt der ersten Messung s{\"a}mtliche Nierenretentionsparameter erh{\"o}ht: Serum-Creatinin lag bei 3.1 mg/dl (2.13-4.18). Der mediane L-Arginin-Serumwert lag mit 71.85 (53-104) μmol/l leicht unter dem Referenzwert, der f{\"u}r eine nierengesunde Population definiert ist (77.4 (59.2 - 95.6) μmol/l). Der durchschnittliche ADMA-Serumwert lag mit 0.65±0.19 μmol/l leicht {\"u}ber dem Referenzwert (0.53±0.12 (0.41-0.65) μmol/l). SDMA-Serumwerte waren mit 1.8 (1.34-2.29) μmol/l deutlich erh{\"o}ht (Normalwerte: 0.225-0.533 μmol/l). Bei Studieneinschluss korrelierte Serum SDMA deutlich mit den Nierenfunktionsparametern Creatinin, Harnstoff und Harns{\"a}ure. Dies unterst{\"u}tzt die Hypothese, dass SDMA auch im akuten Nierenversagen ein Marker der renalen Funktion ist. Die positive Korrelation mit CRP, LDH und inversem Albumin mit SDMA zeigt dessen zus{\"a}tzliche Funktion als Indikator f{\"u}r den Schweregrad einer septischen Erkrankung. Außerdem korrelierte SDMA positiv mit der Mortalit{\"a}t. 70 Personen erf{\"u}llten die Kriterien einer Erholung der Nierenfunktion und konnten f{\"u}r eine Zweitmessung (t2) eingeschlossen werden. Im Vergleich zu t1 sank Serum-Creatinin bei t2 um mehr als die H{\"a}lfte (3.7 mg/dl (Zeitpunkt t1) auf 1.7 mg/dl (Zeitpunkt t2)). L-Arginin-Werte blieben unver{\"a}ndert, w{\"a}hrend SDMA deutlich (35\%) und ADMA-Spiegel leicht (10\%) signifikant fielen. Analog zum Zeitpunkt t1, zeigte sich auch in der Zweitmessung eine ausgepr{\"a}gte positive Korrelation von SDMA (t2) und Creatinin (t2). Außerdem zeigte SDMA 2 eine signifikante Korrelation mit dem Alter, mit anderen Vorerkrankungen (Hypertonie, chronische Niereninsuffizienz) sowie mit der Mortalit{\"a}t. Letzteres deutet auf eine potentielle prognostische Relevanz hin und wurde eingehender untersucht. Hierf{\"u}r wurden die Studienteilnehmer in die Untergruppen der {\"U}berlebenden und Nicht-{\"U}berlebenden eingeteilt. Follow-up Informationen konnten von 118 Patienten erhoben werden. Von diesen waren insgesamt 17\% (n=20) innerhalb des Beobachtungszeitraumes verstorben. Die verstorbenen Patienten waren im Durchschnitt mit 76.8 Jahren signifikant {\"a}lter als die {\"u}brigen Patienten (63.7 Jahre) und h{\"a}ufiger an Hypertonus, CKD und Diabetes mellitus erkrankt. Zudem zeigte sich bei diesen Patienten SDMA zum Zeitpunkt t2 mit 1.84 μmol/l um ein Drittel signifikant h{\"o}her, als bei den {\"U}berlebenden (1.21 μmol/l). L-Arginin war mit 66.7 μmol/l um ca. 30\% niedriger, als bei Patienten, die das ANV {\"u}berlebten (92.4 μmol/l). Somit war auch die L-Arginin/ SDMA Ratio (t2) signifikant erniedrigt, was durch das inhibitorische Potential von SDMA eine geringere intrazellul{\"a}re L-Arginin Verf{\"u}gbarkeit und damit eine verminderte Produktion von NO bedingen k{\"o}nnte. Dies k{\"o}nnte einen pathophysiologischen Mechanismus darstellen. In univariaten Cox-Regressionsanalysen zeigte sich, dass SDMA (t1), SDMA (t2) und L-Arginin/SDMA Ratio (t2) sowie das Alter und die L{\"a}nge der Hospitalisationsdauer mit einer erh{\"o}hten Mortalit{\"a}t assoziiert waren. Außerdem korrelierten Begleiterkrankungen, wie Hypertonus, Diabetes mellitus und chronische Niereninsuffizienz (CKD) mit der Mortalit{\"a}t. Weiterhin zeigte sich, dass SDMA 1 ein unabh{\"a}ngiger mit der Mortalit{\"a}t korrelierender Parameter war, f{\"u}r den ein prognostischer Grenzwert existiert. Bei Patienten mit einem Serum-SDMA-Spiegel (t1) {\"u}ber 2.26 μmol/l war das kumulative {\"U}berleben signifikant vermindert im Vergleich zu Patienten mit einem Serumspiegel unter diesem SDMA cut-off-Wert. Die vorliegende Arbeit zeigt erstmals einen Zusammenhang zwischen der H{\"o}he des Serum-SDMA-Spiegels und dem Ausmaß der renaler Funktionseinschr{\"a}nkung sowie der {\"U}berlebenswahrscheinlichkeit bei Patienten mit akutem Nierenversagen. Aufgrund der guten Korrelation mit den Creatinin-Serum-Spiegeln scheint Serum-SDMA auch im akuten Nierenversagen ein ad{\"a}quater endogener Marker der renalen Funktion zu sein. Zus{\"a}tzlich durch die unabh{\"a}ngige Assoziation mit der Mortalit{\"a}t im follow-up sowie seiner Assoziation mit prognostisch relevanten nicht-renalen Laborparametern, wie Albumin und CRP k{\"o}nnte Serum-SDMA in Zukunft im klinischen Alltag zur Risikostratifizierung von Patienten im akuten Nierenversagen beitragen.},
  subject      = {Arginin},
  language  = {de}
}
@article{MuellerSienerthDietzHoltzetal.2011,
  author    = {M{\"u}ller-Sienerth, Nicole and Dietz, Lena and Holtz, Philipp and Kapp, Markus and Grigoleit, G{\"o}tz Ulrich and Schmuck, Carsten and Wajant, Harald and Siegmund, Daniela},
  title     = {SMAC Mimetic BV6 Induces Cell Death in Monocytes and Maturation of Monocyte-Derived Dendritic Cells},
  series = {PLoS ONE},
  volume    = {6},
  journal   = {PLoS ONE},
  number    = {6},
  doi       = {10.1371/journal.pone.0021556},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-142415},
  pages     = {e21556},
  year      = {2011},
  abstract  = {Background: Compounds mimicking the inhibitory effect of SMAC / DIABLO on X-linked inhibitor of apoptosis (XIAP) have been developed with the aim to achieve sensitization for apoptosis of tumor cells resistant due to deregulated XIAP expression. It turned out that SMAC mimetics also have complex effects on the NF kappa B system and TNF signaling. In view of the overwhelming importance of the NF kappa B transcription factors in the immune system, we analyzed here the effects of the SMAC mimetic BV6 on immune cells. Principal Findings: BV6 induced apoptotic and necrotic cell death in monocytes while T-cells, dendritic cells and macrophages were largely protected against BV6-induced cell death. In immature dendritic cells BV6 treatment resulted in moderate activation of the classical NF kappa B pathway, but it also diminished the stronger NF kappa B-inducing effect of TNF and CD40L. Despite its inhibitory effect on TNF- and CD40L signaling, BV6 was able to trigger maturation of immature DCs as indicated by upregulation of CD83, CD86 and IL12. Significance: The demonstrated effects of SMAC mimetics on immune cells may complicate the development of tumor therapeutic concepts based on these compounds but also arise the possibility to exploit them for the development of immune stimulatory therapies.},
  language  = {en}
}
@article{RauertStuehmerBargouetal.2011,
  author    = {Rauert, H. and St{\"u}hmer, T. and Bargou, R. and Wajant, H. and Siegmund, D.},
  title     = {TNFR1 and TNFR2 regulate the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-76092},
  year      = {2011},
  abstract  = {The huge majority of myeloma cell lines express TNFR2 while a substantial subset of them failed to show TNFR1 expression. Stimulation of TNFR1 in the TNFR1-expressing subset of MM cell lines had no or only a very mild effect on cellular viability. Surprisingly, however, TNF stimulation enhanced cell death induction by CD95L and attenuated the apoptotic effect of TRAIL. The contrasting regulation of TRAIL- and CD95L-induced cell death by TNF could be traced back to the concomitant NFjBmediated upregulation of CD95 and the antiapoptotic FLIP protein. It appeared that CD95 induction, due to its strength, overcompensated a rather moderate upregulation of FLIP so that the net effect of TNF-induced NFjB activation in the context of CD95 signaling is pro-apoptotic. TRAIL-induced cell death, however, was antagonized in response to TNF because in this context only the induction of FLIP is relevant. Stimulation of TNFR2 in myeloma cells leads to TRAF2 depletion. In line with this, we observed cell death induction in TNFR1-TNFR2-costimulated JJN3 cells. Our studies revealed that the TNF-TNF receptor system adjusts the responsiveness of the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms that generate a highly context-dependent net effect on myeloma cell survival.},
  subject      = {Medizin},
  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}
}
@article{TrebingElMeserySchaeferetal.2014,
  author    = {Trebing, J. and El-Mesery, M. and Sch{\"a}fer, V. and Weisenberger, D. and Siegmund, D. and Silence, K. and Wajant, H.},
  title     = {CD70-restricted specific activation of TRAILR1 or TRAILR2 using scFv-targeted TRAIL mutants},
  series = {Cell Death \& Disease},
  volume    = {5},
  journal   = {Cell Death \& Disease},
  doi       = {10.1038/cddis.2013.555},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120078},
  pages     = {e1035},
  year      = {2014},
  abstract  = {To combine the CD27 stimulation inhibitory effect of blocking CD70 antibodies with an antibody-dependent cellular cytotoxicity (ADCC)-independent, cell death-inducing activity for targeting of CD70-expressing tumors, we evaluated here fusion proteins of the apoptosis-inducing TNF family member TRAIL and a single-chain variable fragment (scFv) derived from a high-affinity llama-derived anti-human CD70 antibody (lαhCD70). A fusion protein of scFv:lαhCD70 with TNC-TRAIL, a stabilized form of TRAIL, showed strongly enhanced apoptosis induction upon CD70 binding and furthermore efficiently interfered with CD70-CD27 interaction. Noteworthy, introduction of recently identified mutations that discriminate between TRAILR1 and TRAILR2 binding into the TRAIL part of scFv:lαhCD70-TNC-TRAIL resulted in TRAIL death receptor-specific fusion proteins with CD70-restricted activity.},
  language  = {en}
}
@article{HoyerSchatzschneiderSchulzSiegmundetal.2012,
  author    = {Hoyer, Jan and Schatzschneider, Ulrich and Schulz-Siegmund, Michaela and Neundorf, Ines},
  title     = {Dimerization of a cell-penetrating peptide leads to enhanced cellular uptake and drug delivery},
  series = {Beilstein Journal of Organic Chemistry},
  volume    = {8},
  journal   = {Beilstein Journal of Organic Chemistry},
  doi       = {10.3762/bjoc.8.204},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133933},
  pages     = {1788-1797},
  year      = {2012},
  abstract  = {Over the past 20 years, cell-penetrating peptides (CPPs) have gained tremendous interest due to their ability to deliver a variety of therapeutically active molecules that would otherwise be unable to cross the cellular membrane due to their size or hydrophilicity. Recently, we reported on the identification of a novel CPP, sC18, which is derived from the C-terminus of the 18 kDa cationic antimicrobial protein. Furthermore, we demonstrated successful application of sC18 for the delivery of functionalized cyclopentadienyl manganese tricarbonyl (cymantrene) complexes to tumor cell lines, inducing high cellular toxicity. In order to increase the potential of the organometallic complexes to kill tumor cells, we were looking for a way to enhance cellular uptake. Therefore, we designed a branched dimeric variant of sC18, (sC18)\(_2\), which was shown to have a dramatically improved capacity to internalize into various cell lines, even primary cells, using flow cytometry and fluorescence microscopy. Cell viability assays indicated increased cytotoxicity of the dimer presumably caused by membrane leakage; however, this effect turned out to be dependent on the specific cell type. Finally, we could show that conjugation of a functionalized cymantrene with (sC18)\(_2\) leads to significant reduction of its IC\(_{50}\) value in tumor cells compared to the respective sC18 conjugate, proving that dimerization is a useful method to increase the drug-delivery potential of a cell-penetrating peptide.},
  language  = {en}
}
@article{RauertStuehmerBargouetal.2011,
  author    = {Rauert, H. and St{\"u}hmer, T. and Bargou, R. and Wajant, H. and Siegmund, D.},
  title     = {TNFR1 and TNFR2 regulate the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms},
  series = {Cell Death and Disease},
  volume    = {2},
  journal   = {Cell Death and Disease},
  doi       = {10.1038/cddis.2011.78},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133486},
  pages     = {e194},
  year      = {2011},
  abstract  = {The huge majority of myeloma cell lines express TNFR2 while a substantial subset of them failed to show TNFR1 expression. Stimulation of TNFR1 in the TNFR1-expressing subset of MM cell lines had no or only a very mild effect on cellular viability. Surprisingly, however, TNF stimulation enhanced cell death induction by CD95L and attenuated the apoptotic effect of TRAIL. The contrasting regulation of TRAIL- and CD95L-induced cell death by TNF could be traced back to the concomitant NFjBmediated upregulation of CD95 and the antiapoptotic FLIP protein. It appeared that CD95 induction, due to its strength, overcompensated a rather moderate upregulation of FLIP so that the net effect of TNF-induced NFjB activation in the context of CD95 signaling is pro-apoptotic. TRAIL-induced cell death, however, was antagonized in response to TNF because in this context only the induction of FLIP is relevant. Stimulation of TNFR2 in myeloma cells leads to TRAF2 depletion. In line with this, we observed cell death induction in TNFR1-TNFR2-costimulated JJN3 cells. Our studies revealed that the TNF-TNF receptor system adjusts the responsiveness of the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms that generate a highly context-dependent net effect on myeloma cell survival},
  language  = {en}
}
@article{RauertWunderlichSiegmundMaieretal.2013,
  author    = {Rauert-Wunderlich, Hilka and Siegmund, Daniela and Maier, Eduard and Giner, Tina and Bargou, Ralf C. and Wajant, Harald and St{\"u}hmer, Thorsten},
  title     = {The IKK Inhibitor Bay 11-7082 Induces Cell Death Independent from Inhibition of Activation of NF kappa B Transcription Factors},
  series = {PLoS ONE},
  volume    = {8},
  journal   = {PLoS ONE},
  number    = {3},
  doi       = {10.1371/journal.pone.0059292},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130140},
  pages     = {e59292},
  year      = {2013},
  abstract  = {Multiple myeloma (MM) displays an NFκB activity-related gene expression signature and about 20\% of primary MM samples harbor genetic alterations conducive to intrinsic NFκB signaling activation. The relevance of blocking the classical versus the alternative NFκB signaling pathway and the molecular execution mechanisms involved, however, are still poorly understood. Here, we comparatively tested NFκB activity abrogation through TPCA-1 (an IKK2 inhibitor), BAY 11-7082 (an IKK inhibitor poorly selective for IKK1 and IKK2), and MLN4924 (an NEDD8 activating enzyme (NAE)-inhibitor), and analyzed their anti-MM activity. Whereas TPCA-1 interfered selectively with activation of the classical NFκB pathway, the other two compounds inhibited classical and alternative NFκB signaling without significant discrimination. Noteworthy, whereas TPCA-1 and MLN4924 elicited rather mild anti-MM effects with slight to moderate cell death induction after 1 day BAY 11-7082 was uniformly highly toxic to MM cell lines and primary MM cells. Treatment with BAY 11-7082 induced rapid cell swelling and its initial effects were blocked by necrostatin-1 or the ROS scavenger BHA, but a lasting protective effect was not achieved even with additional blockade of caspases. Because MLN4924 inhibits the alternative NFκB pathway downstream of IKK1 at the level of p100 processing, the quite discordant effects between MLN4924 and BAY 11-7082 must thus be due to blockade of IKK1-mediated NFκB-independent necrosis-inhibitory functions or represent an off-target effect of BAY 11-7082. In accordance with the latter, we further observed that concomitant knockdown of IKK1 and IKK2 did not have any major short-term adverse effect on the viability of MM cells.},
  language  = {en}
}
@article{ElMeseryTrebingSchaferetal.2013,
  author    = {El-Mesery, M. and Trebing, J. and Schafer, V. and Weisenberger, D. and Siegmund, D. and Wajant, H.},
  title     = {CD40-directed scFv-TRAIL fusion proteins induce CD40-restricted tumor cell death and activate dendritic cells},
  series = {Cell Death \& Disease},
  volume    = {4},
  journal   = {Cell Death \& Disease},
  number    = {e916},
  doi       = {10.1038/cddis.2013.402},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-128777},
  year      = {2013},
  abstract  = {Targeted cancer therapy concepts often aim at the induction of adjuvant antitumor immunity or stimulation of tumor cell apoptosis. There is further evidence that combined application of immune stimulating and tumor apoptosis-inducing compounds elicits a synergistic antitumor effect. Here, we describe the development and characterization of bifunctional fusion proteins consisting of a single-chain variable fragment (scFv) domain derived from the CD40-specific monoclonal antibody G28-5 that is fused to the N-terminus of stabilized trimeric soluble variants of the death ligand TNF-related apoptosis-inducing ligand (TRAIL). As shown before by us and others for other cell surface antigen-targeted scFv-TRAIL fusion proteins, scFv:G28-TRAIL displayed an enhanced capacity to induce apoptosis upon CD40 binding. Studies with scFv:G28 fusion proteins of TRAIL mutants that discriminate between the two TRAIL death receptors, TRAILR1 and TRAILR2, further revealed that the CD40 binding-dependent mode of apoptosis induction of scFv:G28-TRAIL is operable with each of the two TRAIL death receptors. Binding of scFv:G28-TRAIL fusion proteins to CD40 not only result in enhanced TRAIL death receptor signaling but also in activation of the targeted CD40 molecule. In accordance with the latter, the scFv:G28-TRAIL fusion proteins triggered strong CD40-mediated maturation of dendritic cells. The CD40-targeted TRAIL fusion proteins described in this study therefore represent a novel type of bifunctional fusion proteins that couple stimulation of antigen presenting cells and apoptosis induction.},
  language  = {en}
}