@phdthesis{Xu2014,
  author    = {Xu, Jiajia},
  title     = {A high-complexity lentiviral shRNA screen identifies synthetic lethal interactions with deregulated N-Myc in neuroblastoma cells},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-103157},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2014},
  abstract  = {In contrast to c-Myc, a deregulated expression of the MYCN gene is restricted to human neuroendocrine tumours. In most cases, the excessive activity of N-Myc results from a MYCN amplification. In neuroblastoma, amplification of MYCN is a predictor of poor prognosis and resistance to therapy. The inability to target the N-Myc protein directly necessitates the search for alternative targets. This project aimed at identifying genes specifically required for growth and survival of cells that express high levels of N-Myc using high-throughput shRNA screening combined with next generation sequencing. The identification and analysis of these genes will shed light on functional interaction partners of N-Myc. We screened a shRNA library containing 18,327 shRNAs and identified 148 shRNAs, which were selectively depleted in the presence of active N-Myc. In addition, shRNAs targeting genes that are involved in p53 and ARF turnover and apoptosis were depleted in the cell population during the screen. These processes are known to affect N-Myc-mediated apoptosis. Consequently, these results biologically validated the screen. The 148 shRNAs that showed a significant synthetic lethal interaction with high levels of N-Myc expression were further analysed using the bioinformatics program DAVID. We found an enrichment of shRNAs that target genes involved in specific biological processes. For example, we validated synthetic lethal interactions for genes such as, THOC1, NUP153 and LARP7, which play an important role in the process of RNA polymerase II-mediated transcription elongation. We also validated genes that are involved in the neddylation pathway. In the screen we identified Cullin 3, which is a component of the BTB-CUL3-Rbx1 ubiquitin ligase that is involved in the turnover of Cyclin E. Depletion of cullin 3 and activation of N-Myc was found to synergistically increase Cyclin E expression to supraphysiological levels, inducing S-phase arrest and a strong DNA damage response. Together with results from a proteomics analysis of N-Myc associated proteins, our results lead us to the following hypothesis: In a neuroblastoma cell, the high levels of N-Myc result in a conflict between RNA polymerase II and the replication machinery during S-phase. The newly identified interaction partners of N- Myc are required to solve this conflict. Consequently, loss of the interaction leads to a massive DNA damage and the induction of apoptosis. In addition, inhibition or depletion of the essential components of the neddylation pathway also results in an unresolvable problem during S-phase.},
  subject      = {Neuroblastom},
  language  = {en}
}
@article{ScognamiglioCabezasWallscheidThieretal.2016,
  author    = {Scognamiglio, Roberta and Cabezas-Wallscheid, Nina and Thier, Marc Christian and Altamura, Sandro and Reyes, Alejandro and Prendergast, {\´A}ine M. and Baumg{\"a}rtner, Daniel and Carnevalli, Larissa S. and Atzberger, Ann and Haas, Simon and von Paleske, Lisa and Boroviak, Thorsten and W{\"o}rsd{\"o}rfer, Philipp and Essers, Marieke A. G. and Kloz, Ulrich and Eisenman, Robert N. and Edenhofer, Frank and Bertone, Paul and Huber, Wolfgang and van der Hoeven, Franciscus and Smith, Austin and Trumpp, Andreas},
  title     = {Myc depletion induces a pluripotent dormant state mimicking diapause},
  series = {Cell},
  volume    = {164},
  journal   = {Cell},
  number    = {4},
  doi       = {10.1016/j.cell.2015.12.033},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-190868},
  pages     = {668-680},
  year      = {2016},
  abstract  = {Mouse embryonic stem cells (ESCs) are maintained in a naive ground state of pluripotency in the presence of MEK and GSK3 inhibitors. Here, we show that ground-state ESCs express low Myc levels. Deletion of both c-myc and N-myc (dKO) or pharmacological inhibition of Myc activity strongly decreases transcription, splicing, and protein synthesis, leading to proliferation arrest. This process is reversible and occurs without affecting pluripotency, suggesting that Myc-depleted stem cells enter a state of dormancy similar to embryonic diapause. Indeed, c-Myc is depleted in diapaused blastocysts, and the differential expression signatures of dKO ESCs and diapaused epiblasts are remarkably similar. Following Myc inhibition, pre-implantation blastocysts enter biosynthetic dormancy but can progress through their normal developmental program after transfer into pseudo-pregnant recipients. Our study shows that Myc controls the biosynthetic machinery of stem cells without affecting their potency, thus regulating their entry and exit from the dormant state.},
  language  = {en}
}
@article{SchmittKellerNourkamiTutdibietal.2011,
  author    = {Schmitt, Jana and Keller, Andreas and Nourkami-Tutdibi, Nasenien and Heisel, Sabrina and Habel, Nunja and Leidinger, Petra and Ludwig, Nicole and Gessler, Manfred and Graf, Norbert and Berthold, Frank and Lenhof, Hans-Peter and Meese, Eckart},
  title     = {Autoantibody Signature Differentiates Wilms Tumor Patients from Neuroblastoma Patients},
  series = {PLoS ONE},
  volume    = {6},
  journal   = {PLoS ONE},
  number    = {12},
  doi       = {10.1371/journal.pone.0028951},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133794},
  pages     = {e28951},
  year      = {2011},
  abstract  = {Several studies report autoantibody signatures in cancer. The majority of these studies analyzed adult tumors and compared the seroreactivity pattern of tumor patients with the pattern in healthy controls. Here, we compared the autoimmune response in patients with neuroblastoma and patients with Wilms tumor representing two different childhood tumors. We were able to differentiate untreated neuroblastoma patients from untreated Wilms tumor patients with an accuracy of 86.8\%, a sensitivity of 87.0\% and a specificity of 86.7\%. The separation of treated neuroblastoma patients from treated Wilms tumor patients' yielded comparable results with an accuracy of 83.8\%. We furthermore identified the antigens that contribute most to the differentiation between both tumor types. The analysis of these antigens revealed that neuroblastoma was considerably more immunogenic than Wilms tumor. The reported antigens have not been found to be relevant for comparative analyses between other tumors and controls. In summary, neuroblastoma appears as a highly immunogenic tumor as demonstrated by the extended number of antigens that separate this tumor from Wilms tumor.},
  language  = {en}
}
@phdthesis{Kalb2021,
  author    = {Kalb, Jacqueline},
  title     = {The role of BRCA1 and DCP1A in the coordination of transcription and replication in neuroblastoma},
  doi       = {10.25972/OPUS-24871},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-248711},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2021},
  abstract  = {The deregulation of the MYC oncoprotein family plays a major role in tumorigenesis and tumour maintenance of many human tumours. Because of their structure and nuclear localisation, they are defined as undruggable targets which makes it difficult to find direct therapeutic approaches. An alternative approach for targeting MYC-driven tumours is the identification and targeting of partner proteins which score as essential in a synthetic lethality screen. Neuroblastoma, an aggressive entity of MYCN-driven tumours coming along with a bad prognosis, are dependent on the tumour suppressor protein BRCA1 as synthetic lethal data showed. BRCA1 is recruited to promoter regions in a MYCN-dependent manner. The aim of this study was to characterise the role of BRCA1 in neuroblastoma with molecular biological methods. BRCA1 prevents the accumulation of RNA Polymerase II (RNAPII) at the promoter region. Its absence results in the formation of DNA/RNA-hybrids, so called R-loops, and DNA damage. To prevent the accumulation of RNAPII, the cell uses DCP1A, a decapping factor known for its cytoplasmatic and nuclear role in mRNA decay. It is the priming factor in the removal of the protective 5'CAP of mRNA, which leads to degradation by exonucleases. BRCA1 is necessary for the chromatin recruitment of DCP1A and its proximity to RNAPII. Cells showed upon acute activation of MYCN a higher dependency on DCP1A. Its activity prevents the deregulation of transcription and leads to proper coordination of transcription and replication. The deregulation of transcription in the absence of DCP1A results in replication fork stalling and leads to activation of the Ataxia telangiectasia and Rad3 related (ATR) kinase. The result is a disturbed cell proliferation to the point of increased apoptosis. The activation of the ATR kinase pathway in the situation where DCP1A is knocked down and MYCN is activated, makes those cells more vulnerable for the treatment with ATR inhibitors. In summary, the tumour suppressor protein BRCA1 and the decapping factor DCP1A, mainly known for its function in the cytoplasm, have a new nuclear role in a MYCN-dependent context. This study shows their essentiality in the coordination of transcription and replication which leads to an unrestrained growth of tumour cells if uncontrolled.},
  subject      = {Neuroblastom},
  language  = {en}
}
@phdthesis{Dehmer2024,
  author    = {Dehmer, Markus},
  title     = {A novel USP11-TCEAL1-mediated mechanism protects transcriptional elongation by RNA Polymerase II},
  doi       = {10.25972/OPUS-36054},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-360544},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2024},
  abstract  = {Deregulated expression of MYC oncoproteins is a driving event in many human cancers. Therefore, understanding and targeting MYC protein-driven mechanisms in tumor biology remain a major challenge. Oncogenic transcription in MYCN-amplified neuroblastoma leads to the formation of the MYCN-BRCA1-USP11 complex that terminates transcription by evicting stalling RNAPII from chromatin. This reduces cellular stress and allows reinitiation of new rounds of transcription. Basically, tumors with amplified MYC genes have a high demand on well orchestration of transcriptional processes-dependent and independent from MYC proteins functions in gene regulation. To date, the cooperation between promoter-proximal termination and transcriptional elongation in cancer cells remains still incomplete in its understanding. In this study the putative role of the dubiquitinase Ubiquitin Specific Protease 11 (USP11) in transcription regulation was further investigated. First, several USP11 interaction partners involved in transcriptional regulation in neuroblastoma cancer cells were identified. In particular, the transcription elongation factor A like 1 (TCEAL1) protein, which assists USP11 to engage protein-protein interactions in a MYCN-dependent manner, was characterized. The data clearly show that TCEAL1 acts as a pro-transcriptional factor for RNA polymerase II (RNAPII)-medi- ated transcription. In detail, TCEAL1 controls the transcription factor S-II (TFIIS), a factor that assists RNAPII to escape from paused sites. The findings claim that TCEAL1 outcompetes the transcription elongation factor TFIIS in a non-catalytic manner on chromatin of highly expressed genes. This is reasoned by the need regulating TFIIS function in transcription. TCEAL1 equili- brates excessive backtracking and premature termination of transcription caused by TFIIS. Collectively, the work shed light on the stoichiometric control of TFIIS demand in transcriptional regulation via the USP11-TCEAL1-USP7 complex. This complex protects RNAPII from TFIIS-mediated termination helping to regulate productive transcription of highly active genes in neuroblastoma.},
  subject      = {Transkription},
  language  = {en}
}