% IMPORTANT: The following is UTF-8 encoded. This means that in the presence % of non-ASCII characters, it will not work with BibTeX 0.99 or older. % Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or % “biber”. @ARTICLE{Laemmerer:294574, author = {A. Laemmerer and C. Lehmann and L. Mayr and K. Bruckner and L. Gabler and D. Senfter and P. Meyer and T. Balber and C. Pirker and C. N. Jaunecker and D. Kirchhofer and P. Vician and M. Griesser and S. Spiegl-Kreinecker and M. T. Schmook and T. Traub-Weidinger and P. Kuess and F. Eckert and A. Federico$^*$ and S. Madlener and N. Stepien and B. Robl and A. Baumgartner and J. A. Hainfellner and K. Dieckmann and C. Dorfer and K. Roessler and N. S. Corsini and K. Holzmann and W. M. Schmidt and A. Peyrl and A. A. Azizi and C. Haberler and A. Beck and S. M. Pfister$^*$ and J. Schueler and D. Loetsch-Gojo and J. A. Knoblich and W. Berger and J. Gojo}, title = {{A}lternative lengthening of telomere-based immortalization renders {H}3{G}34{R} -mutant diffuse hemispheric glioma hypersensitive to {PARP} inhibitor combination regimens.}, journal = {Neuro-Oncology}, volume = {27}, number = {3}, issn = {1522-8517}, address = {Oxford}, publisher = {Oxford Univ. Press}, reportid = {DKFZ-2024-02349}, pages = {811-827}, year = {2025}, note = {2025 Mar 7;27(3):811-827}, abstract = {Diffuse hemispheric glioma, H3G34R/V-mutant (DHG-H3G34) is characterized by poor prognosis and lack of effective treatment options. DHG-H3G34R further harbor deactivation of Alpha-Thalassemia/Mental Retardation Syndrome X-linked protein (ATRX; $DHG-H3G34R_ATRX)$ suggesting a unique interaction of these two oncogenic alterations. In this study, we dissect their cell biological interplay, investigate the impact on telomere stabilization and, consequently, validate a targeted therapy approach.We characterized patient-derived primary pediatric high-grade glioma (pHGG) models for telomere-maintenance mechanisms, DNA damage stress (including protein expression, pH2AX/Rad51 foci, cell-cycle arrest) and their sensitivity towards poly-ADP polymerase inhibitor (PARPi) combinations. Human induced pluripotent stem cells (iPSCs) were used for modelling the disease. The anticancer activity of PARPi combinations in vivo was studied in Chorioallantoic Membrane (CAM) and orthotopic in vivo experiments. Finally, we treated a $DHG-H3G34R_ATRX$ patient with a PARPi combination therapy.We elaborate that alternative lengthening of telomeres (ALT) is a key characteristic of $DHG-H3G34R_ATRX.$ A dominant cooperative effect between H3G34R and ATRX loss in ALT activation also became apparent in iPSCs, which endogenously exert telomerase activity. In both, patient-derived $DHG-H3G34R_ATRX$ models and H3G34R+/ATRX- iPSCs, the ALT phenotype was associated with increased basal DNA damage stress, mediating synergistic susceptibility towards PARPi (talazoparib, niraparib) combinations with topoisomerase-I inhibitors (topotecan, irinotecan). In a first-of-its-kind case, treatment of a $DHG-H3G34R_ATRX$ patient with the brain-penetrant PARP inhibitor niraparib and topotecan resulted in a significant tumor reduction.Our preclinical and clinical data strongly support the further development of PARPis together with DNA damage stress-inducing treatment regimens for $DHG-H3G34R_ATRX.$}, keywords = {ATRX (Other) / DNA damage (Other) / Diffuse hemispheric glioma (Other) / H3G34R (Other) / PARP inhibitor (Other)}, cin = {B062 / HD01}, ddc = {610}, cid = {I:(DE-He78)B062-20160331 / I:(DE-He78)HD01-20160331}, pnm = {312 - Funktionelle und strukturelle Genomforschung (POF4-312)}, pid = {G:(DE-HGF)POF4-312}, typ = {PUB:(DE-HGF)16}, pubmed = {pmid:39556024}, doi = {10.1093/neuonc/noae228}, url = {https://inrepo02.dkfz.de/record/294574}, }