TY - JOUR A1 - Prieto‐Garcia, Cristian A1 - Hartmann, Oliver A1 - Reissland, Michaela A1 - Braun, Fabian A1 - Fischer, Thomas A1 - Walz, Susanne A1 - Schülein‐Völk, Christina A1 - Eilers, Ursula A1 - Ade, Carsten P. A1 - Calzado, Marco A. A1 - Orian, Amir A1 - Maric, Hans M. A1 - Münch, Christian A1 - Rosenfeldt, Mathias A1 - Eilers, Martin A1 - Diefenbacher, Markus E. T1 - Maintaining protein stability of ∆Np63 via USP28 is required by squamous cancer cells JF - EMBO Molecular Medicine N2 - The transcription factor ∆Np63 is a master regulator of epithelial cell identity and essential for the survival of squamous cell carcinoma (SCC) of lung, head and neck, oesophagus, cervix and skin. Here, we report that the deubiquitylase USP28 stabilizes ∆Np63 and maintains elevated ∆NP63 levels in SCC by counteracting its proteasome‐mediated degradation. Impaired USP28 activity, either genetically or pharmacologically, abrogates the transcriptional identity and suppresses growth and survival of human SCC cells. CRISPR/Cas9‐engineered in vivo mouse models establish that endogenous USP28 is strictly required for both induction and maintenance of lung SCC. Our data strongly suggest that targeting ∆Np63 abundance via inhibition of USP28 is a promising strategy for the treatment of SCC tumours. KW - ∆Np63 KW - NOTCH KW - squamous cell carcinoma KW - 28 Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218303 VL - 12 IS - 4 ER - TY - JOUR A1 - Blättner, Sebastian A1 - Das, Sudip A1 - Paprotka, Kerstin A1 - Eilers, Ursula A1 - Krischke, Markus A1 - Kretschmer, Dorothee A1 - Remmele, Christian W. A1 - Dittrich, Marcus A1 - Müller, Tobias A1 - Schuelein-Voelk, Christina A1 - Hertlein, Tobias A1 - Mueller, Martin J. A1 - Huettel, Bruno A1 - Reinhardt, Richard A1 - Ohlsen, Knut A1 - Rudel, Thomas A1 - Fraunholz, Martin J. T1 - Staphylococcus aureus Exploits a Non-ribosomal Cyclic Dipeptide to Modulate Survival within Epithelial Cells and Phagocytes JF - PLoS Pathogens N2 - Community-acquired (CA) Staphylococcus aureus cause various diseases even in healthy individuals. Enhanced virulence of CA-strains is partly attributed to increased production of toxins such as phenol-soluble modulins (PSM). The pathogen is internalized efficiently by mammalian host cells and intracellular S. aureus has recently been shown to contribute to disease. Upon internalization, cytotoxic S. aureus strains can disrupt phagosomal membranes and kill host cells in a PSM-dependent manner. However, PSM are not sufficient for these processes. Here we screened for factors required for intracellular S. aureus virulence. We infected escape reporter host cells with strains from an established transposon mutant library and detected phagosomal escape rates using automated microscopy. We thereby, among other factors, identified a non-ribosomal peptide synthetase (NRPS) to be required for efficient phagosomal escape and intracellular survival of S. aureus as well as induction of host cell death. By genetic complementation as well as supplementation with the synthetic NRPS product, the cyclic dipeptide phevalin, wild-type phenotypes were restored. We further demonstrate that the NRPS is contributing to virulence in a mouse pneumonia model. Together, our data illustrate a hitherto unrecognized function of the S. aureus NRPS and its dipeptide product during S. aureus infection. KW - cell death KW - cytotoxicity KW - Staphylococcus aureus KW - host cells KW - neutrophils KW - macrophages KW - transposable elements KW - epithelial cells Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-180380 VL - 12 IS - 9 ER - TY - JOUR A1 - Wiegering, Armin A1 - Pfann, Christina A1 - Uthe, Friedrich Wilhelm A1 - Otto, Christoph A1 - Rycak, Lukas A1 - Mäder, Uwe A1 - Gasser, Martin A1 - Waaga-Gasser, Anna-Maria A1 - Eilers, Martin A1 - Germer, Christoph-Thomas T1 - CIP2A Influences Survival in Colon Cancer and Is Critical for Maintaining Myc Expression JF - PLoS ONE N2 - The cancerous inhibitor of protein phosphatase 2A (CIP2A) is an oncogenic factor that stabilises the c-Myc protein. CIP2A is overexpressed in several tumours, and expression levels are an independent marker for long-term outcome. To determine whether CIP2A expression is elevated in colon cancer and whether it might serve as a prognostic marker for survival, we analysed CIP2A mRNA expression by real-time PCR in 104 colon cancer samples. CIP2A mRNA was overexpressed in colon cancer samples and CIP2A expression levels correlated significantly with tumour stage. We found that CIP2A serves as an independent prognostic marker for disease-free and overall survival. Further, we investigated CIP2A-dependent effects on levels of c-Myc, Akt and on cell proliferation in three colon cancer cell lines by silencing CIP2A using small interfering (si) and short hairpin (sh) RNAs. Depletion of CIP2A substantially inhibited growth of colon cell lines and reduced c-Myc levels without affecting expression or function of the upstream regulatory kinase, Akt. Expression of CIP2A was found to be dependent on MAPK activity, linking elevated c-Myc expression to deregulated signal transduction in colon cancer. KW - caco-2 cells KW - carcinomas KW - colon KW - colorectal cancer KW - MAPK signaling cascades KW - metastasis KW - protein expression KW - small interferring RNA Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-97252 ER - TY - JOUR A1 - Elkon, Ran A1 - Loayza-Puch, Fabricio A1 - Korkmaz, Gozde A1 - Lopes, Rui A1 - van Breugel, Pieter C A1 - Bleijerveld, Onno B A1 - Altelaar, AF Maarten A1 - Wolf, Elmar A1 - Lorenzin, Francesca A1 - Eilers, Martin A1 - Agami, Reuven T1 - Myc coordinates transcription and translation to enhance transformation and suppress invasiveness JF - EMBO reports N2 - c‐Myc is one of the major human proto‐oncogenes and is often associated with tumor aggression and poor clinical outcome. Paradoxically, Myc was also reported as a suppressor of cell motility, invasiveness, and metastasis. Among the direct targets of Myc are many components of the protein synthesis machinery whose induction results in an overall increase in protein synthesis that empowers tumor cell growth. At present, it is largely unknown whether beyond the global enhancement of protein synthesis, Myc activation results in translation modulation of specific genes. Here, we measured Myc‐induced global changes in gene expression at the transcription, translation, and protein levels and uncovered extensive transcript‐specific regulation of protein translation. Particularly, we detected a broad coordination between regulation of transcription and translation upon modulation of Myc activity and showed the connection of these responses to mTOR signaling to enhance oncogenic transformation and to the TGFβ pathway to modulate cell migration and invasiveness. Our results elucidate novel facets of Myc‐induced cellular responses and provide a more comprehensive view of the consequences of its activation in cancer cells. KW - c‐Myc KW - transcriptional responses KW - translational regulation KW - transcription KW - transformation KW - metastasis KW - cancer KW - protein biosynthesis & quality control Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-150373 VL - 16 IS - 12 ER - TY - JOUR A1 - Sander, Bodo A1 - Xu, Wenshan A1 - Eilers, Martin A1 - Popov, Nikita A1 - Lorenz, Sonja T1 - A conformational switch regulates the ubiquitin ligase HUWE1 JF - eLife N2 - The human ubiquitin ligase HUWE1 has key roles in tumorigenesis, yet it is unkown how its activity is regulated. We present the crystal structure of a C-terminal part of HUWE1, including the catalytic domain, and reveal an asymmetric auto-inhibited dimer. We show that HUWE1 dimerizes in solution and self-associates in cells, and that both occurs through the crystallographic dimer interface. We demonstrate that HUWE1 is inhibited in cells and that it can be activated by disruption of the dimer interface. We identify a conserved segment in HUWE1 that counteracts dimer formation by associating with the dimerization region intramolecularly. Our studies reveal, intriguingly, that the tumor suppressor p14ARF binds to this segment and may thus shift the conformational equilibrium of HUWE1 toward the inactive state. We propose a model, in which the activity of HUWE1 underlies conformational control in response to physiological cues—a mechanism that may be exploited for cancer therapy. KW - Medicine KW - Structural Biology KW - Molecular Biophysics KW - HUWE1 KW - HECT Ligase KW - Ubiquitin KW - P14ARF KW - X-Ray Chrystallography KW - Enzyme Regulation Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171862 VL - 6 ER - TY - INPR A1 - Löffler, Mona C. A1 - Mayer, Alexander E. A1 - Trujillo Viera, Jonathan A1 - Loza Valdes, Angel A1 - El-Merahib, Rabih A1 - Ade, Carsten P. A1 - Karwen, Till A1 - Schmitz, Werner A1 - Slotta, Anja A1 - Erk, Manuela A1 - Janaki-Raman, Sudha A1 - Matesanz, Nuria A1 - Torres, Jorge L. A1 - Marcos, Miguel A1 - Sabio, Guadalupe A1 - Eilers, Martin A1 - Schulze, Almut A1 - Sumara, Grzegorz T1 - Protein kinase D1 deletion in adipocytes enhances energy dissipation and protects against adiposity T2 - The EMBO Journal N2 - Nutrient overload in combination with decreased energy dissipation promotes obesity and diabetes. Obesity results in a hormonal imbalance, which among others, activates G-protein coupled receptors utilizing diacylglycerol (DAG) as secondary messenger. Protein kinase D1 (PKD1) is a DAG effector which integrates multiple nutritional and hormonal inputs, but its physiological role in adipocytes is unknown. Here, we show that PKD1 promotes lipogenesis and suppresses mitochondrial fragmentation, biogenesis, respiration, and energy dissipation in an AMP-activated protein kinase (AMPK)-dependent manner. Moreover, mice lacking PKD1 in adipocytes are resistant to diet-induced obesity due to elevated energy expenditure. Beiging of adipocytes promotes energy expenditure and counteracts obesity. Consistently, deletion of PKD1 promotes expression of the β3-adrenergic receptor (ADRB3) in a CCAAT/enhancerbinding protein (C/EBP)-α and δ-dependent manner, which leads to the elevated expression of beige markers in adipocytes and subcutaneous adipose tissue. Finally, deletion of PKD1 in adipocytes improves insulin sensitivity and ameliorates liver steatosis. Thus, loss of PKD1 in adipocytes increases energy dissipation by several complementary mechanisms and might represent an attractive strategy to treat obesity and its related complications. KW - AMP-activated protein kinase (AMPK) KW - Beige adipocytes KW - β3 adrenergic receptor (ADRB3) KW - C/EBP KW - Protein kinase D1 (PKD1) Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176093 ER - TY - JOUR A1 - Teutschbein, Janka A1 - Haydn, Johannes M. A1 - Samans, Birgit A1 - Krause, Michael A1 - Eilers, Martin A1 - Schartl, Manfred A1 - Meierjohann, Svenja T1 - Gene expression analysis after receptor tyrosine kinase activation reveals new potential melanoma proteins N2 - Background: Melanoma is an aggressive tumor with increasing incidence. To develop accurate prognostic markers and targeted therapies, changes leading to malignant transformation of melanocytes need to be understood. In the Xiphophorus melanoma model system, a mutated version of the EGF receptor Xmrk (Xiphophorus melanoma receptor kinase) triggers melanomagenesis. Cellular events downstream of Xmrk, such as the activation of Akt, Ras, B-Raf or Stat5, were also shown to play a role in human melanomagenesis. This makes the elucidation of Xmrk downstream targets a useful method for identifying processes involved in melanoma formation. Methods: Here, we analyzed Xmrk-induced gene expression using a microarray approach. Several highly expressed genes were confirmed by realtime PCR, and pathways responsible for their induction were revealed using small molecule inhibitors. The expression of these genes was also monitored in human melanoma cell lines, and the target gene FOSL1 was knocked down by siRNA. Proliferation and migration of siRNA-treated melanoma cell lines were then investigated. Results: Genes with the strongest upregulation after receptor activation were FOS-like antigen 1 (Fosl1), early growth response 1 (Egr1), osteopontin (Opn), insulin-like growth factor binding protein 3 (Igfbp3), dual-specificity phosphatase 4 (Dusp4), and tumor-associated antigen L6 (Taal6). Interestingly, most genes were blocked in presence of a SRC kinase inhibitor. Importantly, we found that FOSL1, OPN, IGFBP3, DUSP4, and TAAL6 also exhibited increased expression levels in human melanoma cell lines compared to human melanocytes. Knockdown of FOSL1 in human melanoma cell lines reduced their proliferation and migration. Conclusion: Altogether, the data show that the receptor tyrosine kinase Xmrk is a useful tool in the identification of target genes that are commonly expressed in Xmrk-transgenic melanocytes and melanoma cell lines. The identified molecules constitute new possible molecular players in melanoma development. Specifically, a role of FOSL1 in melanomagenic processes is demonstrated. These data are the basis for future detailed analyses of the investigated target genes. KW - Melanoma Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-67900 ER - TY - JOUR A1 - Schülein-Völk, Christina A1 - Wolf, Elmar A1 - Zhu, Jing A1 - Xu, Wenshan A1 - Taranets, Lyudmyla A1 - Hellmann, Andreas A1 - Jänicke, Laura A. A1 - Diefenbacher, Markus E. A1 - Behrens, Axel A1 - Eilers, Martin A1 - Popov, Nikita T1 - Dual Regulation of Fbw7 Function and Oncogenic Transformation by Usp28 JF - CELL REPORTS N2 - Fbw7, the substrate recognition subunit of SCF(Fbw7) ubiquitin ligase, mediates the turnover of multiple proto-oncoproteins and promotes its own degradation. Fbw7-dependent substrate ubiquitination is antagonized by the Usp28 deubiquitinase. Here, we show that Usp28 preferentially antagonizes autocatalytic ubiquitination and stabilizes Fbw7, resulting in dose-dependent effects in Usp28 knockout mice. Monoallelic deletion of Usp28 maintains stable Fbw7 but drives Fbw7 substrate degradation. In contrast, complete knockout triggers Fbw7 degradation and leads to the accumulation of Fbw7 substrates in several tissues and embryonic fibroblasts. On the other hand, overexpression of Usp28 stabilizes both Fbw7 and its substrates. Consequently, both complete loss and ectopic expression of Usp28 promote Ras-driven oncogenic transformation. We propose that dual regulation of Fbw7 activity by Usp28 is a safeguard mechanism for maintaining physiological levels of proto-oncogenic Fbw7 substrates, which is equivalently disrupted by loss or overexpression of Usp28. KW - Fbw7 KW - oncogenic transformation Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-118219 SN - 2211-1247 N1 - The sequencing data have been submitted to the GEO repository under accession number GSE59354. VL - 9 IS - 3 ER - TY - JOUR A1 - Hönnemann, Jan A1 - Sanz-Moreno, Adrian A1 - Wolf, Elmar A1 - Eilers, Martin A1 - Elsässer, Hans-Peter T1 - Miz1 Is a Critical Repressor of cdkn1a during Skin Tumorigenesis JF - PLoS One N2 - The transcription factor Miz1 forms repressive DNA-binding complexes with the Myc, Gfi-1 and Bcl-6 oncoproteins. Known target genes of these complexes encode the cyclin-dependent kinase inhibitors (CKIs) cdkn2b (p15\(^{Ink4}\)), cdkn1a (p21\(^{Cip1}\)), and cdkn1c (p57\(^{Kip2}\)). Whether Miz1-mediated repression is important for control of cell proliferation in vivo and for tumor formation is unknown. Here we show that deletion of the Miz1 POZ domain, which is critical for Miz1 function, restrains the development of skin tumors in a model of chemically-induced, Ras-dependent tumorigenesis. While the stem cell compartment appears unaffected, interfollicular keratinocytes lacking functional Miz1 exhibit a reduced proliferation and an accelerated differentiation of the epidermis in response to the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). Tumorigenesis, proliferation and normal differentiation are restored in animals lacking cdkn1a, but not in those lacking cdkn2b. Our data demonstrate that Miz1-mediated attenuation of cell cycle arrest pathways via repression of cdkn1a has a critical role during tumorigenesis in the skin. KW - transcription factor MIZ-1 KW - cell-cycle arrest KW - c-myc KW - tumor suppressor KW - cancer cells KW - POZ domain KW - P21 KW - differentiation KW - P15(INK4B) KW - senescence Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-133285 VL - 7 IS - 4 ER - TY - JOUR A1 - Sanz-Moreno, Adrian A1 - Fuhrmann, David A1 - Wolf, Elmar A1 - von Eyss, Björn A1 - Eilers, Martin A1 - Elsässer, Hans-Peter T1 - Miz1 Deficiency in the Mammary Gland Causes a Lactation Defect by Attenuated Stat5 Expression and Phosphorylation JF - PLOS ONE N2 - Miz1 is a zinc finger transcription factor with an N-terminal POZ domain. Complexes with Myc, Bcl-6 or Gfi-1 repress expression of genes like Cdkn2b (p15(Ink4)) or Cd-kn1a (p21(Cip1)). The role of Miz1 in normal mammary gland development has not been addressed so far. Conditional knockout of the Miz1 POZ domain in luminal cells during pregnancy caused a lactation defect with a transient reduction of glandular tissue, reduced proliferation and attenuated differentiation. This was recapitulated in vitro using mouse mammary gland derived HC11 cells. Further analysis revealed decreased Stat5 activity in Miz1 Delta POZ mammary glands and an attenuated expression of Stat5 targets. Gene expression of the Prolactin receptor (PrlR) and ErbB4, both critical for Stat5 phosphorylation (pStat5) or pStat5 nuclear translocation, was decreased in Miz1 Delta POZ females. Microarray, ChIP-Seq and gene set enrichment analysis revealed a down-regulation of Miz1 target genes being involved in vesicular transport processes. Our data suggest that deranged intracellular transport and localization of PrlR and ErbB4 disrupt the Stat5 signalling pathway in mutant glands and cause the observed lactation phenotype. KW - C-MYC KW - transcription factor MIZ-1 KW - breast-cancer cells KW - gene expression KW - epithelial cells KW - prolactin KW - transgenic mice KW - growth KW - differentiation KW - proliferation Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-117286 VL - 9 IS - 2 ER -