@article{FischerHartmannReisslandetal.2022,
  author    = {Fischer, Thomas and Hartmann, Oliver and Reissland, Michaela and Prieto-Garcia, Cristian and Klann, Kevin and Pahor, Nikolett and Sch{\"u}lein-V{\"o}lk, Christina and Baluapuri, Apoorva and Polat, B{\"u}lent and Abazari, Arya and Gerhard-Hartmann, Elena and Kopp, Hans-Georg and Essmann, Frank and Rosenfeldt, Mathias and M{\"u}nch, Christian and Flentje, Michael and Diefenbacher, Markus E.},
  title     = {PTEN mutant non-small cell lung cancer require ATM to suppress pro-apoptotic signalling and evade radiotherapy},
  series = {Cell \& Bioscience},
  volume    = {12},
  journal   = {Cell \& Bioscience},
  issn      = {2045-3701},
  doi       = {10.1186/s13578-022-00778-7},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-299865},
  year      = {2022},
  abstract  = {Background Despite advances in treatment of patients with non-small cell lung cancer, carriers of certain genetic alterations are prone to failure. One such factor frequently mutated, is the tumor suppressor PTEN. These tumors are supposed to be more resistant to radiation, chemo- and immunotherapy. Results We demonstrate that loss of PTEN led to altered expression of transcriptional programs which directly regulate therapy resistance, resulting in establishment of radiation resistance. While PTEN-deficient tumor cells were not dependent on DNA-PK for IR resistance nor activated ATR during IR, they showed a significant dependence for the DNA damage kinase ATM. Pharmacologic inhibition of ATM, via KU-60019 and AZD1390 at non-toxic doses, restored and even synergized with IR in PTEN-deficient human and murine NSCLC cells as well in a multicellular organotypic ex vivo tumor model. Conclusion PTEN tumors are addicted to ATM to detect and repair radiation induced DNA damage. This creates an exploitable bottleneck. At least in cellulo and ex vivo we show that low concentration of ATM inhibitor is able to synergise with IR to treat PTEN-deficient tumors in genetically well-defined IR resistant lung cancer models.},
  language  = {en}
}
@article{WielandStrisselSchorleetal.2021,
  author    = {Wieland, Annalena and Strissel, Pamela L. and Schorle, Hannah and Bakirci, Ezgi and Janzen, Dieter and Beckmann, Matthias W. and Eckstein, Markus and Dalton, Paul D. and Strick, Reiner},
  title     = {Brain and breast cancer cells with PTEN loss of function reveal enhanced durotaxis and RHOB dependent amoeboid migration utilizing 3D scaffolds and aligned microfiber tracts},
  series = {Cancers},
  volume    = {13},
  journal   = {Cancers},
  number    = {20},
  issn      = {2072-6694},
  doi       = {10.3390/cancers13205144},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-248443},
  year      = {2021},
  abstract  = {Background: Glioblastoma multiforme (GBM) and metastatic triple-negative breast cancer (TNBC) with PTEN mutations often lead to brain dissemination with poor patient outcome, thus new therapeutic targets are needed. To understand signaling, controlling the dynamics and mechanics of brain tumor cell migration, we implemented GBM and TNBC cell lines and designed 3D aligned microfibers and scaffolds mimicking brain structures. Methods: 3D microfibers and scaffolds were printed using melt electrowriting. GBM and TNBC cell lines with opposing PTEN genotypes were analyzed with RHO-ROCK-PTEN inhibitors and PTEN rescue using live-cell imaging. RNA-sequencing and qPCR of tumor cells in 3D with microfibers were performed, while scanning electron microscopy and confocal microscopy addressed cell morphology. Results: In contrast to the PTEN wildtype, GBM and TNBC cells with PTEN loss of function yielded enhanced durotaxis, topotaxis, adhesion, amoeboid migration on 3D microfibers and significant high RHOB expression. Functional studies concerning RHOB-ROCK-PTEN signaling confirmed the essential role for the above cellular processes. Conclusions: This study demonstrates a significant role of the PTEN genotype and RHOB expression for durotaxis, adhesion and migration dependent on 3D. GBM and TNBC cells with PTEN loss of function have an affinity for stiff brain structures promoting metastasis. 3D microfibers represent an important tool to model brain metastasizing tumor cells, where RHO-inhibitors could play an essential role for improved therapy.},
  language  = {en}
}
@phdthesis{Lutyj2020,
  author    = {Lutyj, Paul},
  title     = {Modulation der Strahlensensibilit{\"a}t mittels alleiniger sowie kombinierter PI3K/mTOR-Inhibierung im Glioblastommodell: die Rolle des PTENs},
  doi       = {10.25972/OPUS-21015},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-210159},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2020},
  abstract  = {Den aktuellen Forschungsgegenstand dieser Arbeit bildet der in Glioblastomen h{\"a}ufig {\"u}beraktivierte PI3K/AKT/mTOR-Signalweg. Eine entscheidende Rolle bei der Aktivierung des Signalwegs spielt das Tumorsuppressorprotein PTEN. Ein mutiertes PTEN sorgt f{\"u}r die zuvor genannte {\"U}beraktivierung des PI3K/AKT/mTOR-Signalwegs und korreliert mit einer Radioresistenz. In der vorliegenden Arbeit wurde die strahlensensibilisierende Wirkung des neuartigen dualen PI3K/mTOR-Inhibitors NVP-BEZ235 an zwei humanen Glioblastomzelllinien mit unterschiedlichem PTEN-Status (GaMG: PTEN wt und U373-MG: PTEN mut) analysiert. Vergleichend dazu erfolgten Untersuchungen mit dem mTOR-Inhibitor Rapamycin und dem PI3K-Inhibitor LY294002. Untersucht wurden die Auswirkungen auf die Zellproliferation, die Strahlensensibilit{\"a}t, das Proteinexpressionsmuster, die Zellzyklusverteilung, die Induktion und Reparaturf{\"a}higkeit des DNS-Schadens sowie die Einleitung des programmierten Zelltods. U373-MG stellte sich im Vergleich zu GaMG als die strahlensensiblere Zelllinie heraus. Des Weiteren konnte gezeigt werden, dass die mTOR-Inhibition durch NVP-BEZ235, unabh{\"a}ngig vom PTEN-Status, f{\"u}r die Einflussnahme auf Proliferation und Proteintranslation vordergr{\"u}ndig ist. Es kam zu keinen radiosensibilisierenden Effekten durch Zugabe von NVP-BEZ235, Rapamycin und LY294002 24 Stunden vor Bestrahlung, was auf das Ausbleiben eines erh{\"o}hten DNA-Schadens und einer verz{\"o}gerten DNA-Reparatur, einen G1-Arrest und der Aktivierung des PI3K-Signalwegs zum Zeitpunkt der Bestrahlung sowie der Unterdr{\"u}ckung der Apoptose zur{\"u}ckzuf{\"u}hren ist. Trotz Ausbleiben radiosensibilisierender Effekt, konnte durch die Testsubstanzen eine starke zytostatische Wirkung gezeigt werden.},
  subject      = {Strahlensensibilit{\"a}t},
  language  = {de}
}
@article{DjuzenovaFiedlerMemmeletal.2019,
  author    = {Djuzenova, Cholpon S. and Fiedler, Vanessa and Memmel, Simon and Katzer, Astrid and Sisario, Dmitri and Brosch, Philippa K. and G{\"o}hrung, Alexander and Frister, Svenja and Zimmermann, Heiko and Flentje, Michael and Sukhorukov, Vladimir L.},
  title     = {Differential effects of the Akt inhibitor MK-2206 on migration and radiation sensitivity of glioblastoma cells},
  series = {BMC Cancer},
  volume    = {19},
  journal   = {BMC Cancer},
  doi       = {10.1186/s12885-019-5517-4},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200290},
  pages     = {299},
  year      = {2019},
  abstract  = {Background Most tumor cells show aberrantly activated Akt which leads to increased cell survival and resistance to cancer radiotherapy. Therefore, targeting Akt can be a promising strategy for radiosensitization. Here, we explore the impact of the Akt inhibitor MK-2206 alone and in combination with the dual PI3K and mTOR inhibitor PI-103 on the radiation sensitivity of glioblastoma cells. In addition, we examine migration of drug-treated cells. Methods Using single-cell tracking and wound healing migration tests, colony-forming assay, Western blotting, flow cytometry and electrorotation we examined the effects of MK-2206 and PI-103 and/or irradiation on the migration, radiation sensitivity, expression of several marker proteins, DNA damage, cell cycle progression and the plasma membrane properties in two glioblastoma (DK-MG and SNB19) cell lines, previously shown to differ markedly in their migratory behavior and response to PI3K/mTOR inhibition. Results We found that MK-2206 strongly reduces the migration of DK-MG but only moderately reduces the migration of SNB19 cells. Surprisingly, MK-2206 did not cause radiosensitization, but even increased colony-forming ability after irradiation. Moreover, MK-2206 did not enhance the radiosensitizing effect of PI-103. The results appear to contradict the strong depletion of p-Akt in MK-2206-treated cells. Possible reasons for the radioresistance of MK-2206-treated cells could be unaltered or in case of SNB19 cells even increased levels of p-mTOR and p-S6, as compared to the reduced expression of these proteins in PI-103-treated samples. We also found that MK-2206 did not enhance IR-induced DNA damage, neither did it cause cell cycle distortion, nor apoptosis nor excessive autophagy. Conclusions Our study provides proof that MK-2206 can effectively inhibit the expression of Akt in two glioblastoma cell lines. However, due to an aberrant activation of mTOR in response to Akt inhibition in PTEN mutated cells, the therapeutic window needs to be carefully defined, or a combination of Akt and mTOR inhibitors should be considered.},
  language  = {en}
}