@article{Prieto‐GarciaHartmannReisslandetal.2020, author = {Prieto-Garcia, Cristian and Hartmann, Oliver and Reissland, Michaela and Braun, Fabian and Fischer, Thomas and Walz, Susanne and Sch{\"u}lein-V{\"o}lk, Christina and Eilers, Ursula and Ade, Carsten P. and Calzado, Marco A. and Orian, Amir and Maric, Hans M. and M{\"u}nch, Christian and Rosenfeldt, Mathias and Eilers, Martin and Diefenbacher, Markus E.}, title = {Maintaining protein stability of ∆Np63 via USP28 is required by squamous cancer cells}, series = {EMBO Molecular Medicine}, volume = {12}, journal = {EMBO Molecular Medicine}, number = {4}, doi = {10.15252/emmm.201911101}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218303}, year = {2020}, abstract = {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.}, language = {en} } @article{SanderXuEilersetal.2017, author = {Sander, Bodo and Xu, Wenshan and Eilers, Martin and Popov, Nikita and Lorenz, Sonja}, title = {A conformational switch regulates the ubiquitin ligase HUWE1}, series = {eLife}, volume = {6}, journal = {eLife}, doi = {10.7554/eLife.21036}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-171862}, year = {2017}, abstract = {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.}, language = {en} } @article{SanzMorenoFuhrmannWolfetal.2014, author = {Sanz-Moreno, Adrian and Fuhrmann, David and Wolf, Elmar and von Eyss, Bj{\"o}rn and Eilers, Martin and Els{\"a}sser, Hans-Peter}, title = {Miz1 Deficiency in the Mammary Gland Causes a Lactation Defect by Attenuated Stat5 Expression and Phosphorylation}, series = {PLOS ONE}, volume = {9}, journal = {PLOS ONE}, number = {2}, doi = {10.1371/journal.pone.0089187}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-117286}, pages = {e89187}, year = {2014}, abstract = {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.}, language = {en} } @article{SchueleinVoelkWolfZhuetal.2014, author = {Sch{\"u}lein-V{\"o}lk, Christina and Wolf, Elmar and Zhu, Jing and Xu, Wenshan and Taranets, Lyudmyla and Hellmann, Andreas and J{\"a}nicke, Laura A. and Diefenbacher, Markus E. and Behrens, Axel and Eilers, Martin and Popov, Nikita}, title = {Dual Regulation of Fbw7 Function and Oncogenic Transformation by Usp28}, series = {CELL REPORTS}, volume = {9}, journal = {CELL REPORTS}, number = {3}, issn = {2211-1247}, doi = {10.1016/j.celrep.2014.09.057}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-118219}, pages = {1099-1109}, year = {2014}, abstract = {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.}, language = {en} } @article{TeutschbeinHaydnSamansetal.2010, author = {Teutschbein, Janka and Haydn, Johannes M. and Samans, Birgit and Krause, Michael and Eilers, Martin and Schartl, Manfred and Meierjohann, Svenja}, title = {Gene expression analysis after receptor tyrosine kinase activation reveals new potential melanoma proteins}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-67900}, year = {2010}, abstract = {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.}, language = {en} } @article{WiegeringPfannUtheetal.2013, author = {Wiegering, Armin and Pfann, Christina and Uthe, Friedrich Wilhelm and Otto, Christoph and Rycak, Lukas and M{\"a}der, Uwe and Gasser, Martin and Waaga-Gasser, Anna-Maria and Eilers, Martin and Germer, Christoph-Thomas}, title = {CIP2A Influences Survival in Colon Cancer and Is Critical for Maintaining Myc Expression}, series = {PLoS ONE}, journal = {PLoS ONE}, doi = {10.1371/journal.pone.0075292}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-97252}, year = {2013}, abstract = {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.}, language = {en} } @article{YankuBitmanLotanZoharetal.2018, author = {Yanku, Yifat and Bitman-Lotan, Eliya and Zohar, Yaniv and Kurant, Estee and Zilke, Norman and Eilers, Martin and Orian, Amir}, title = {Drosophila HUWE1 ubiquitin ligase regulates endoreplication and antagonizes JNK signaling during salivary gland development}, series = {Cells}, volume = {7}, journal = {Cells}, number = {10}, issn = {2073-4409}, doi = {10.3390/cells7100151}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-197630}, pages = {151}, year = {2018}, abstract = {The HECT-type ubiquitin ligase HECT, UBA and WWE Domain Containing 1, (HUWE1) regulates key cancer-related pathways, including the Myc oncogene. It affects cell proliferation, stress and immune signaling, mitochondria homeostasis, and cell death. HUWE1 is evolutionarily conserved from Caenorhabditis elegance to Drosophila melanogaster and Humans. Here, we report that the Drosophila ortholog, dHUWE1 (CG8184), is an essential gene whose loss results in embryonic lethality and whose tissue-specific disruption establishes its regulatory role in larval salivary gland development. dHUWE1 is essential for endoreplication of salivary gland cells and its knockdown results in the inability of these cells to replicate DNA. Remarkably, dHUWE1 is a survival factor that prevents premature activation of JNK signaling, thus preventing the disintegration of the salivary gland, which occurs physiologically during pupal stages. This function of dHUWE1 is general, as its inhibitory effect is observed also during eye development and at the organismal level. Epistatic studies revealed that the loss of dHUWE1 is compensated by dMyc proeitn expression or the loss of dmP53. dHUWE1 is therefore a conserved survival factor that regulates organ formation during Drosophila development.}, language = {en} }