@article{SchulmeyerFaschingHaeberleetal.2023, author = {Schulmeyer, Carla E. and Fasching, Peter A. and H{\"a}berle, Lothar and Meyer, Julia and Schneider, Michael and Wachter, David and Ruebner, Matthias and P{\"o}schke, Patrik and Beckmann, Matthias W. and Hartmann, Arndt and Erber, Ramona and Gass, Paul}, title = {Expression of the immunohistochemical markers CK5, CD117, and EGFR in molecular subtypes of breast cancer correlated with prognosis}, series = {Diagnostics}, volume = {13}, journal = {Diagnostics}, number = {3}, issn = {2075-4418}, doi = {10.3390/diagnostics13030372}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-304987}, year = {2023}, abstract = {Molecular-based subclassifications of breast cancer are important for identifying treatment options and stratifying the prognosis in breast cancer. This study aimed to assess the prognosis relative to disease-free survival (DFS) and overall survival (OS) in patients with triple-negative breast cancer (TNBC) and other subtypes, using a biomarker panel including cytokeratin 5 (CK5), cluster of differentiation 117 (CD117), and epidermal growth factor receptor (EGFR). This cohort-case study included histologically confirmed breast carcinomas as cohort arm. From a total of 894 patients, 572 patients with early breast cancer, sufficient clinical data, and archived tumor tissue were included. Using the immunohistochemical markers CK5, CD117, and EGFR, two subgroups were formed: one with all three biomarkers negative (TBN) and one with at least one of those three biomarkers positive (non-TBN). There were significant differences between the two biomarker subgroups (TBN versus non-TBN) in TNBC for DFS (p = 0.04) and OS (p = 0.02), with higher survival rates (DFS and OS) in the non-TBN subgroup. In this study, we found the non-TBN subgroup of TNBC lesions with at least one positive biomarker of CK5, CD117, and/or EGFR, to be associated with longer DFS and OS.}, language = {en} } @article{RaoGiannicoLeoneetal.2020, author = {Rao, Luigia and Giannico, Donato and Leone, Patrizia and Solimando, Antonio Giovanni and Maiorano, Eugenio and Caporusso, Concetta and Duda, Loren and Tamma, Roberto and Mallamaci, Rosanna and Susca, Nicola and Buonavoglia, Alessio and Da Vi{\`a}, Matteo Claudio and Ribatti, Domenico and De Re, Vall{\`i} and Vacca, Angelo and Racanelli, Vito}, title = {HB-EGF-EGFR signaling in bone marrow endothelial cells mediates angiogenesis associated with multiple myeloma}, series = {Cancers}, volume = {12}, journal = {Cancers}, number = {1}, issn = {2072-6694}, doi = {10.3390/cancers12010173}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200786}, year = {2020}, abstract = {Epidermal growth factor receptor (EGFR) and its ligand heparin-binding EGF-like growth factor (HB-EGF) sustain endothelial cell proliferation and angiogenesis in solid tumors, but little is known about the role of HB-EGF-EGFR signaling in bone marrow angiogenesis and multiple myeloma (MM) progression. We found that bone marrow endothelial cells from patients with MM express high levels of EGFR and HB-EGF, compared with cells from patients with monoclonal gammopathy of undetermined significance, and that overexpressed HB-EGF stimulates EGFR expression in an autocrine loop. We also found that levels of EGFR and HB-EGF parallel MM plasma cell number, and that HB-EGF is a potent inducer of angiogenesis in vitro and in vivo. Moreover, blockade of HB-EGF-EGFR signaling, by an anti-HB-EGF neutralizing antibody or the EGFR inhibitor erlotinib, limited the angiogenic potential of bone marrow endothelial cells and hampered tumor growth in an MM xenograft mouse model. These results identify HB-EGF-EGFR signaling as a potential target of anti-angiogenic therapy, and encourage the clinical investigation of EGFR inhibitors in combination with conventional cytotoxic drugs as a new therapeutic strategy for MM.}, language = {en} } @article{KressJessenMarquardtetal.2021, author = {Kreß, Julia Katharina Charlotte and Jessen, Christina and Marquardt, Andr{\´e} and Hufnagel, Anita and Meierjohann, Svenja}, title = {NRF2 enables EGFR signaling in melanoma cells}, series = {International Journal of Molecular Sciences}, volume = {22}, journal = {International Journal of Molecular Sciences}, number = {8}, issn = {1422-0067}, doi = {10.3390/ijms22083803}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-260222}, year = {2021}, abstract = {Receptor tyrosine kinases (RTK) are rarely mutated in cutaneous melanoma, but the expression and activation of several RTK family members are associated with a proinvasive phenotype and therapy resistance. Epidermal growth factor receptor (EGFR) is a member of the RTK family and is only expressed in a subgroup of melanomas with poor prognosis. The insight into regulators of EGFR expression and activation is important for the understanding of the development of this malignant melanoma phenotype. Here, we describe that the transcription factor NRF2, the master regulator of the oxidative and electrophilic stress response, mediates the expression and activation of EGFR in melanoma by elevating the levels of EGFR as well as its ligands EGF and TGFα. ChIP sequencing data show that NRF2 directly binds to the promoter of EGF, which contains a canonical antioxidant response element. Accordingly, EGF is induced by oxidative stress and is also increased in lung adenocarcinoma and head and neck carcinoma with mutationally activated NRF2. In contrast, regulation of EGFR and TGFA occurs by an indirect mechanism, which is enabled by the ability of NRF2 to block the activity of the melanocytic lineage factor MITF in melanoma. MITF effectively suppresses EGFR and TGFA expression and therefore serves as link between NRF2 and EGFR. As EGFR was previously described to stimulate NRF2 activity, the mutual activation of NRF2 and EGFR pathways was investigated. The presence of NRF2 was necessary for full EGFR pathway activation, as NRF2-knockout cells showed reduced AKT activation in response to EGF stimulation compared to controls. Conversely, EGF led to the nuclear localization and activation of NRF2, thereby demonstrating that NRF2 and EGFR are connected in a positive feedback loop in melanoma. In summary, our data show that the EGFR-positive melanoma phenotype is strongly supported by NRF2, thus revealing a novel maintenance mechanism for this clinically challenging melanoma subpopulation.}, language = {en} } @article{SchieflerPiontekDoescheretal.2014, author = {Schiefler, Carlotta and Piontek, Guido and Doescher, Johannes and Schuettler, Dominik and Mißlbeck, Martin and Rudelius, Martina and Haug, Anna and Reiter, Rudolf and Brockhoff, Gero and Pickhard, Anja}, title = {Inhibition of SphK1 reduces radiation-induced migration and enhances sensitivity to cetuximab treatment by affecting the EGFR/SphK1 crosstalk}, series = {Oncotarget}, volume = {5}, journal = {Oncotarget}, number = {20}, issn = {1949-2553}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120929}, pages = {9877-9888}, year = {2014}, abstract = {SphK1 is known to play a role in tumor progression, resistance to radiochemotherapy, and migration patterns. As the overall survival rates of squamous cell carcinoma of the head and neck (HNSCC) remain poor due to limitations in surgery and irradiation and chemotherapy resistance, SphK1 is an important enzyme to investigate. The purpose of this study was to elucidate the impact of SphK1 on irradiation efficacy of HNSCC in-vitro with emphasis on EGFR signaling. By immunhistochemical staining we found a positive correlation between EGFR and SphK1 expression in patient specimens. In colony formation assays irradiation sensitive cell lines showed a poor response to cetuximab, an EGFR inhibitor, and SKI-II, a SphK1 inhibitor, and vice versa. In irradiation sensitive cells an enhanced reduction of cell migration and survival was found upon simultaneous targeting of EGFR and SphK1. In the present study, we elucidated a linkage between the two signaling pathways with regard to the efficacy of cetuximab treatment and the impact on the migration behavior of tumor cells. We investigated the biological impact of inhibiting these pathways and examined the biochemical implications after different treatments. An understanding of the processes involved could help to improve the treatment of patients with HNSCC.}, language = {en} } @phdthesis{Niederlechner2013, author = {Niederlechner, Stefanie}, title = {Assessment of the basic molecular mechanisms underlying L-glutamine's cytoprotective effects after intestinal injury}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-77399}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2013}, abstract = {Critical illness like sepsis, shock, and intestinal bowel disease are one of the leading causes of morbidity and mortality in the US and around the world. At present, studies to define new therapeutic interventions that can protect tissues and cells against injury and attenuate inflammation are fields of intense investigation. While research over the past decade has clearly identified GLN as a vital stress substrate facilitating cellular survival following injury, the initiation steps in GLN's cytoprotective molecular mechanism still remain elusive. Previously published work suggested that stabilization of ECM proteins and activation of ECM receptor osmosignaling may play a central role in the orchestration of many cellular pathways following stress. Thus, I hypothesized that preservation of ECM protein and EGFR levels as well as ECM receptor signaling play key roles in the molecular mechanisms underlying GLN's protection against thermal injury in the intestine. I was able to confirm via Western blotting and by using silencing RNA against FN, Ntn-1, EGFR, and their negative controls, that GLN-mediated preservation of FN, Ntn-1, and EGFR levels is critical in GLN's protection against hyperthermia in IEC-6 cells. By using a selective FN-Integrin interaction inhibitor GRGDSP, its negative control peptide GRGESP, and Src-kinase inhibitor PP2, I showed that FN-Integrin signaling and Src-kinase activation are essential in GLN-mediated protection in the intestine. This applied to EGFR signaling as demonstrated using the EGFR tyrosine kinase inhibitor AG1478. In addition to GRGDSP and AG1478, ERK1/2 inhibitors PD98059 and UO126 as well as the p38MAPK inhibitor SB203580 revealed that GLN is protective by activating ERK1/2 and dephosphorylating p38MAPK via FN-Integrin and EGFR signaling. However, GLN-mediated PI3-K/Akt/Hsp70 activation seems to occur independently of FN-Integrin and EGFR signaling as indicated by Western blots as well as experiments using the PI3-K inhibitor LY294002, GRGDSP, and AG1478. The results showed that GLN activates cell survival signaling pathways via integrins as well as EGFRs after hyperthermia. Moreover, I found that GLN-mediated preservation of FN expression after HS is regulated via PI3-K signaling. Whether GLN-mediated PI3-K signaling happens simultaneously to FN-Integrin and EGFR signaling or whether PI3-K signaling coordinates FN-Integrin and EGFR signaling needs to be investigated in future studies. Further, experiments with PD98059 and GRGDSP revealed that ERK1/2 assists in mediating transactivation of HSF-1 following HS. This leads to increases in Hsp70 expression via FN-Integrin signaling, which is known to attenuate apoptosis after thermal injury. Fluorescence microscopy results indicated that HS and GLN regulate cell are size changes and the morphology of F-actin via FN-Integrin signaling. Experiments using GRGDSP and GRGESP showed that GLN enhances cellular survival via FN-Integrin signaling in a manner that does not require increased intracellular GLN concentrations (as quantified using LC-MS/MS). In summary, my thesis work gives new and potentially clinically relevant mechanistic insights into GLN-mediated molecular cell survival pathways. These results warrant clinical translation to assess if clinical outcome of critically ill patients suffering from gastrointestinal diseases can be improved by GLN treatment and/or by targeting the molecular pathways found in my studies.}, subject = {Glutamin}, language = {en} } @phdthesis{Laisney2010, author = {Laisney, Juliette Agn{\`e}s Genevi{\`e}ve Claire}, title = {Characterisation and regulation of the Egfr/Egfr ligand system in fish models for melanoma}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-51369}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2010}, abstract = {Fish of the genus Xiphophorus belong to the oldest animal models in cancer research. The oncogene responsible for the generation of spontaneous aggressive melanoma encodes for a mutated epidermal growth factor receptor (Egfr) and is called xmrk for Xiphophorus melanoma receptor kinase. Xmrk constitutive activation mechanisms and subsequent signaling pathways have already been investigated and charaterized but it is still unknown if Egfr ligands may also play a role in Xmrk-driven melanoma formation. To investigate the potential role of Egfr ligands in Xmrk-driven melanoma, I firstly analyzed the evolution of teleost and tetrapod Egfr/Egfr ligand systems. I especially focused on the analysis on the medaka fish, a closely related species to Xiphophorus, for which the whole genome has been sequenced. I could identify all seven Egfr ligands in medaka and could show that the two teleost-specific Egfr copies of medaka display dissimilar expression patterns in adult tissues together with differential expression of Egfr ligand subsets, arguing for subfunctionalization of receptor functions in this fish. Our phylogenetic and synteny analyses supported the hypothesis that only one gene in the chordate ancestor gave rise to the diversity of Egfr ligands found in vertebrate genomes today. I also could show that the Egfr extracellular subdomains implicated in ligand binding are not evolutionary conserved between tetrapods and teleosts, making the use of heterologous ligands in experiments with fish cells debatable. Despite its well understood and straight-forward process, Xmrk-driven melanomagenesis in Xiphophorus is problematic to further investigate in vivo. Our laboratory recently established a new melanoma animal model by generating transgenic mitf::xmrk medaka fishes, a Xiphophorus closely related species offering many more advantages. These fishes express xmrk under the control of the pigment-cell specific Mitf promoter. During my PhD thesis, I participated in the molecular analysis of the stably transgenic medaka and could show that the Xmrk-induced signaling pathways are similar when comparing Xiphophorus with transgenic mitf::xmrk medaka. These data together with additional RNA expression, protein, and histology analyses showed that Xmrk expression under the control of a pigment cell-specific promoter is sufficient to induce melanoma in the transgenic medaka, which develop very stereotyped tumors, including uveal and extracutaneous melanoma, with early onset during larval stages. To further investigate the potential role of Egfr ligands in Xmrk-driven melanoma, I made use of two model systems. One of them was the above mentioned mitf::xmrk medaka, the other was an in-vitro cell culture system, where the EGF-inducible Xmrk chimera HERmrk is stably expressed in murine melanocytes. Here I could show that HERmrk activation strongly induced expression of amphiregulin (Areg) and heparin-binding EGF-like growth factor (Hbegf) in melanocytes. This regulation was dependent on the MAPK and SRC signaling pathways. Moreover, upregulation of Adam10 and Adam17, the two major sheddases of Egfr ligands, was observed. I also could demonstrate the functionality of the growth factors by invitro analyses. Using the mitf::xmrk medaka model I could also show the upregulation of a subset of ligand genes, namely egf, areg, betacellulin (btc) and epigen (epgn) as well as upregulation of medaka egfrb in tumors from fish with metastatic melanoma. All these results converge to support an Xmrk-induced autocrine Egfr ligand loop. Interestingly, my in-vitro experiments with conditioned supernatant from medaka Egf- and Hbegf-producing cells revealed that not only Xiphophorus Egfrb, but also the pre-activated Xmrk could be further stimulated by the ligands. Altogether, I could show with in-vitro and in-vivo experiments that Xmrk is capable of inducing a functional autocrine Egfr ligand loop. These data confirm the importance of autocrine loops in receptor tyrosine kinase (RTK)-dependent cancer development and show the possibility for a constitutively active RTK to strengthen its oncogenic signaling by ligand binding.}, subject = {Schwertk{\"a}rpfling}, language = {en} } @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} }