@phdthesis{Hart2004, author = {Hart, Stefan}, title = {Characterisation of the molecular mechanisms of EGFR signal transactivation in human cancer}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10067}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2004}, abstract = {In a variety of established tumour cell lines, but also in primary mammary epithelial cells metalloprotease-dependent transactivation of the EGFR, and EGFR characteristic downstream signalling events were observed in response to stimulation with physiological concentrations of GPCR agonists such as the mitogens LPA and S1P as well as therapeutically relevant concentrations of cannabinoids. Moreover, this study reveals ADAM17 and HB-EGF as the main effectors of this mechanism in most of the cancer cell lines investigated. However, depending on the cellular context and GPCR agonist, various different members of the ADAM family are selectively recruited for specific ectodomain shedding of proAR and/or proHB-EGF and subsequent EGFR activation. Furthermore, biological responses induced by LPA or S1P such as migration in breast cancer and HNSCC cells, depend on ADAM17 and proHB-EGF/proAR function, respectively, suggesting that highly abundant GPCR ligands may play a role in tumour development and progression. Moreover, EGFR signal transactivation could be identified as the mechanistic link between cannabinoid receptors and the activation of mitogen activated protein kinases (MAPK) ERK1/2 as well as pro-survival Akt/PKB signalling. Depending on the cellular context, cannabinoid-induced signal cross-communication was mediated by shedding of proAmphiregulin and/or proHB-EGF by ADAM17. Most importantly, our data show that concentrations of THC comparable to those detected in the serum of patients after THC administration accelerate proliferation of cancer cells instead of apoptosis and thereby may contribute to cancer progression in patients.}, subject = {Epidermaler Wachstumsfaktor-Rezeptor}, language = {en} } @phdthesis{Gruse2020, author = {Gruse, Tamara}, title = {Untersuchung der Rolle der ERK-Dimerisierung bei der ERK1/2- vermittelten Proliferation von Tumorzellen}, doi = {10.25972/OPUS-15984}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159847}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2020}, abstract = {Bei vielen Erkrankungen wie z.B. Herzhypertrophie, Diabetes und Entz{\"u}ndungen spielt die Raf-MEK-ERK-Signalkaskade eine wichtige Rolle. ERK1/2 ist in vielen zellul{\"a}ren Prozessen, u.a. Proliferation, Differenzierung, Wachstum, Hypertrophie und Apoptose involviert. Auch in der Tumorentstehung besitzt dieser MAPK-Signalweg eine signifikante Funktion, da er bei ca. 50\% aller Krebsarten deutlich aktiviert ist. Ziel dieser Arbeit war es, die Rolle einer neu entdeckten Phosphorylierungsstelle an Threonin188 an ERK2 bei der Entstehung und der m{\"o}glichen Therapie von Tumoren zu erarbeiten. Daf{\"u}r wurde ein Myc-ERK2309-357-Peptid verwendet, das 2013 in der Arbeitsgruppe Lorenz entwickelt wurde. Myc-ERK2309-357 zeigte in bisher unver{\"o}ffentlichten Versuchen, dass es direkt an ERK2 bindet, eine Dimerisierung von ERK1/2 hemmen und eine vermehrte Lokalisation von ERK2 im Zellkern verhindern kann. Im Rahmen dieses Projekts konnten wir belegen, dass mit Hilfe des Myc-ERK2309-357-Peptids die Tumorzellproliferation von verschiedenen Krebszelllinien (Caco-2, SCC68, PC/1-1 und PC/13-1) um 60-80\% vermindert werden konnte. Des Weiteren konnten wir zeigen, dass Myc-ERK2309-357 keinen Einfluss auf die Phosphorylierung von ERK1/2 am TEY-Motiv besitzt. Die Aktivierung von ERK1/2 durch die Kinasen MEK1/2 wird somit nicht beeinflusst und die zytosolischen ERK-Funktionen, wie z.B. der anti-apoptotische Effekt, w{\"u}rden somit bestehen bleiben. Außerdem fanden wir heraus, dass Myc-ERK2309-357 im Vergleich zu den MEK-Inhibitoren U0126 und PD98059 und verglichen mit dem EGF-Rezeptor-Antik{\"o}rper Cetuximab die Proliferation signifikant besser hemmt.}, subject = {Dimerisierung}, language = {de} } @article{GattenloehnerEtschmannKunzmannetal.2010, author = {Gattenl{\"o}hner, S. and Etschmann, B. and Kunzmann, V. and Thalheimer, A. and Hack, M. and Kleber, G. and Einsele, H. and Germer, C. and M{\"u}ller-Hermelink, H.-K.}, title = {Concordance of KRAS/BRAF Mutation Status in Metastatic Colorectal Cancer before and after Anti-EGFR Therapy}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68240}, year = {2010}, abstract = {Anti-EGFR targeted therapy is a potent strategy in the treatment of metastatic colorectal cancer (mCRC) but activating mutations in the KRAS gene are associated with poor response to this treatment. Therefore, KRAS mutation analysis is employed in the selection of patients for EGFR-targeted therapy and various studies have shown a high concordance between the mutation status in primary CRC and corresponding metastases. However, although development of therapy related resistance occurs also in the context of novel drugs such as tyrosine kinase-inhibitors the effect of the anti-EGFR treatment on the KRAS/BRAF mutation status itself in recurrent mCRC has not yet been clarified. Therefore, we analyzed 21mCRCs before/after anti-EGFR therapy and found a pre-/posttherapeutic concordance of the KRAS/BRAF mutation status in 20 of the 21 cases examined. In the one discordant case, further analyses revealed that a tumor mosaicism or multiple primary tumors were present, indicating that anti-EGFR therapy has no influence on KRAS/BRAF mutation status in mCRC. Moreover, as the preselection of patients with a KRASwt genotype for anti-EGFR therapy has become a standard procedure, sample sets such ours might be the basis for future studies addressing the identification of potential anti-EGFR therapy induced genetic alterations apart from KRAS/BRAF mutations.}, subject = {Krebs}, language = {en} } @phdthesis{Christensen2003, author = {Christensen, Morten Overby}, title = {Dynamics of human DNA Topoisomerases I and II}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-4927}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2003}, abstract = {The first goal of this study was to develop cell lines with a stable expression of bio-fluorescent topo II and topo I. This was successfully achieved using a bicistronic vector system. Control experiments showed that proteins of expected size were expressed, and that GFP-tagged topos I, IIa, and IIb were active in the cells and fully integrated in the endogenous pools of the enzymes. These cell-lines provided a novel tool for investigating the cell biology of human DNA topoisomerases. Our most important finding was, that both types of mammalian topoisomerases are entirely mobile proteins that are in continuous and rapid flux between all compartments of the nucleus and between the cytososl and the chromosomes of mitotic cells. This was particularly surprising with regard to topo II, which is considered to be a structural component of the nuclear matrix and the chromosome scaffold. We must conclude that if this was the case, then these architectural structures appear to be much more dynamic than believed until now. In this context it should also be mentioned, that the alignment of topo II with the central axes of the chromosome arms, which has until now been considered a hall-mark of the enzyme's association with the chromosomal scaffold, is not seen in vivo and can be demonstrated to be to some extent an artefact of immunohistochemistry. Furthermore, we show that the two isoforms of topo II (a and b) have a different localisation during mitotic cell division, supporting the general concept that topo II functions at mitosis are exclusively assigned to the a-form, whereas at interphase the two isoenzymes work in concert. Despite unrestricted mobility within the entire nuclear space, topoisomerases I and II impose as mostly nucleolar proteins. We show that this is due to the fact that in the nucleoli they are moving slower than in the nucleoplasm. The decreased nucleolar mobility cannot be due to DNA-interactions, because compounds that fix topoisomerases to the DNA deplete them from the nucleoli. Interestingly, the subnucleolar distribution of topoisomerases I and II was complementary. The type II enzyme filled the entire nucleolar space, but excluded the fibrial centers, whereas topo I accumulated at the fibrial centers, an allocation directed by the enzyme's N-terminus. During mitosis, it also mediates association with the nucleolar organising regions of the acrocentric chromosomes. Thus, topo I stays associated with the rDNA during the entire cell-cycle and consistently colocalizes there with RNA-polymerase I. Finally, we show that certain cancer drugs believed to act by stabilising covalent catalytic DNA-intermediates of topoisomerases, do indeed immobilize the enzymes in living cells. Interestingly, these drugs do not target topoisomerases in the nucleoli but only in the nucleoplasm.}, subject = {Mensch}, language = {en} } @article{CaviezelAeschbachLutzetal.1984, author = {Caviezel, M. and Aeschbach, A. P. and Lutz, Werner K. and Schlatter, C.}, title = {Reduction of covalent binding of aflatoxin B1 to rabbit liver DNA after immunization against this carcinogen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-80116}, year = {1984}, abstract = {The covalent binding of [3H]aflatoxin B1 (AF) to liver DNA was determined, 6 h after oral administration to male rabbits. A Covalent Binding Index, CBI (flmol AF/mol DNA-P)/(mmol AF/kg b. w.) = 8,500 was found. Pretreatment of rabbits with AF coupled to bovine serum albumin in Freund's adjuvant led to the production of AF-directed antibodies. Administration of [3H]AF to such immunized rabbits resulted in a CJH of only 2,500, i.e., the iiDJ{.lUnization provided a protection by a factor of more than 3. Although this is encouraging evidence for the potential of active immunization against genotoxic carcinogens, a nurober of pointswill have to be clarified, such as the time course for the DNA binding and the question of a possible shift to other target cells.}, subject = {Krebs}, language = {en} } @phdthesis{Anany2019, author = {Anany, Mohamed Ahmed Mohamed Mohamed}, title = {Enhancement of Toll-like receptor3 (TLR3)-induced death signaling by TNF-like weak inducer of apoptosis (TWEAK)}, doi = {10.25972/OPUS-18975}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-189757}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) is a member of the TNF superfamily (TNFSF) and is as such initially expressed as type II class transmembrane glycoprotein from which a soluble ligand form can be released by proteolytic processing. While the expression of TWEAK has been detected at the mRNA level in various cell lines and cell types, its cell surface expression has so far only been documented for dendritic cells, monocytes and interferon-γ stimulated NK cells. The fibroblast growth factor-inducible-14 (Fn14) is a TRAF2-interacting receptor of the TNF receptor superfamily (TNFRSF) and is the only receptor for TWEAK. The expression of Fn14 is strongly induced in a variety of non-hematopoietic cell types after tissue injury. The TWEAK/Fn14 system induces pleiotropic cellular activities such as induction of proinflammatory genes, stimulation of cellular angiogenesis, proliferation, differentiation, migration and in rare cases induction of apoptosis. On the other side, Toll-like receptor3 (TLR3) is one of DNA- and RNA-sensing pattern recognition receptors (PRRs), plays a crucial role in the first line of defense against virus and invading foreign pathogens and cancer cells. Polyinosinic-polycytidylic acid poly(I:C) is a synthetic analog of dsRNA, binds to TLR3 which acts through the adapter TRIF/TICAM1, leading to cytokine secretion, NF-B activation, IRF3 nuclear translocation, inflammatory response and may also elicit the cell death. TWEAK sensitizes cells for TNFR1-induced apoptosis and necroptosis by limiting the availability of protective TRAF2-cIAP1 and TRAF2-cIAP2 complexes, which interact with the TNFR1-binding proteins TRADD and RIPK1. In accordance with the fact that poly(I:C)-induced signaling also involves these proteins, we found enhanced necroptosis-induction in HaCaT and HeLa-RIPK3 by poly(I:C) in the presence of TWEAK (Figure 24). Analysis of a panel of TRADD, FADD, RIPK1 and caspase-8 knockout cells revealed furthermore similarities and differences in the way how these molecules act in cell death signaling by poly(I:C)/TWEAK and TNF and TRAIL. RIPK1 turned out to be essential for poly(I:C)/TWEAK-induced caspase-8-mediated apoptosis but was dispensable for these responses in TNF and TRAIL signaling. Lack of FADD protein abrogated TRAIL- but not TNF- and poly(I:C)-induced necroptosis. Moreover, we observed that both long and short FLIP rescued HaCaT and HeLa-RIPK3 cells from poly(I:C)-induced apoptosis or necroptosis. To sum up, our results demonstrate that TWEAK, which is produced by interferon stimulated myeloid cells, controls the induction of apoptosis and necroptosis by the TLR3 ligand poly(I:C) and may thus contribute to cancer or anti-viral immunity treatment.}, subject = {Immunologe}, language = {en} } @misc{OPUS4-4636, title = {Blick - das Magazin der Julius-Maximilians-Universit{\"a}t W{\"u}rzburg. Ausgabe 1/1999. Schwerpunktthema: Interdisziplin{\"a}res Tumorzentrum W{\"u}rzburg}, volume = {1/1999}, organization = {Julius-Maximilians-Universit{\"a}t W{\"u}rzburg}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-44999}, year = {1999}, abstract = {Inhalts{\"u}bersicht zum Schwerpunktthema: - Erkennung, Therapie und Nachsorge von Tumoren - Tumorkonforme Strahlentherapie - Kinder mit Hirntumoren - Autologe Transplantation von Blutstammzellen - Tumorimmunit{\"a}t am Beispiel des malignen Melanoms - Immuntherapie: ein Antik{\"o}rper gegen Magenkrebs - Brustkrebs - die Lymphknoten und der Einfluss der Gene - Krebs in der unteren Speiser{\"o}hre u.a.}, subject = {W{\"u}rzburg}, language = {de} } @misc{OPUS4-4637, title = {Blick - das Magazin der Julius-Maximilians-Universit{\"a}t W{\"u}rzburg. Ausgabe 2/1999. Schwerpunktthema: "Molekulare Mechanismen kanzerogener Prim{\"a}rver{\"a}nderungen}, volume = {2/1999}, organization = {Julius-Maximilians-Universit{\"a}t W{\"u}rzburg}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-45008}, year = {1999}, abstract = {Inhalts{\"u}bersicht zum Schwerpunktthema: - Krebsentstehung auf der Ebene der Molek{\"u}le - Ver{\"a}nderungen am Erbgut ohne direkte DNA-Sch{\"a}digung - Magenlymphom: von der Infektion zum Tumor - Chaos in der Erbsubstanz - Hautkrebs bei Fischen: ein Tumorgen und die Folgen - Ewiges Leben - ein Albtraum? - Wilms-Tumoren - komplexer als vermutet u.a.}, subject = {W{\"u}rzburg}, language = {de} }