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  • 1
    In: Neuro-Oncology, 2018, Vol. 20(suppl2), pp.i182-i182
    Description: Precise diagnosis and robust detection of actionable alterations is required for individualized treatments. The Pediatric Targeted Therapy (PTT) 2.0 program aims at improvement of diagnostic accuracy and detection of targetable alterations by extended molecular diagnostics. The impact of these analyses on clinical management is being evaluated. Pediatric patients with relapsed or progressive tumors after treatment according to standard protocols are included, independent of the histological diagnosis. Formalin fixed paraffin embedded material and a blood sample for germline correction are requested. The methods employed are DNA methylation array, customized targeted gene panel sequencing (130 genes), RNA and Sanger sequencing in selected cases, and immunohistochemistry (IHC) of selected markers. A questionnaire-based follow-up is used to determine the clinical impact of the analysis. We have included n=111 cases from 22.02.2017.-31.12.2017, analysis was completed for n=83 cases (75%) at the time of abstract submission. The most common entities were brain tumors (n=56/83, 67%). DNA methylation array alone allowed diagnostic classification in n=45/83 cases (54.2%) and n=34/56 brain tumor cases (60,7%), respectively. Actionable targets as detected by copy number calculation, gene panel sequencing, RNA sequencing and IHC were found in n=47/83 cases (56.6%). Pathogenic germline alterations with clinical relevance were identified in n=7/83 cases (8.4%) and were confirmed by Sanger sequencing. Follow-up analyses are ongoing. In conclusion, combination of next-generation diagnostics such as methylation arrays and targeted sequencing in addition to selected IHC markers added robust information concerning diagnosis and targetable alterations. The impact on clinical decision-making and on outcome is currently being evaluated.
    Keywords: Medicine;
    ISSN: 1522-8517
    E-ISSN: 1523-5866
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  • 2
    Language: English
    In: CNS oncology, July 2013, Vol.2(4), pp.359-76
    Description: Histone deacetylase inhibitors (HDACis) have fascinated researchers in almost all fields of oncology for many years owing to their pleiotropic effects on nearly every aspect of cancer biology. Since the approval of the first HDACi vorinostat for the treatment of cutaneous T-cell leukemia in 2006, more than a hundred clinical trials have been initiated with a HDACi as a single agent or in combination therapy. Although a number of epigenetic and nonepigenetic molecular mechanisms of action have been proposed, biomarkers for response prediction and patient selection are still lacking. One of the inherent problems in the field of HDACis is their 'reverse' history of drug development: these compounds reached clinical application at an early stage, before the biology of their targets, HDAC1-11, was sufficiently understood. This review summarizes the current knowledge on the human family of HDACs as drug targets in pediatric and adult brain tumors, the efficacy and molecular action of HDACis in preclinical models, as well as the current status of the clinical development of these compounds in the field of neuro-oncology.
    Keywords: Brain Neoplasms -- Drug Therapy ; Histone Deacetylase Inhibitors -- Therapeutic Use ; Histone Deacetylases -- Metabolism
    ISSN: 20450907
    E-ISSN: 2045-0915
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  • 3
    Language: English
    In: Ecker, J., I. Oehme, R. Mazitschek, A. Korshunov, M. Kool, T. Hielscher, J. Kiss, et al. 2015. “Targeting class I histone deacetylase 2 in MYC amplified group 3 medulloblastoma.” Acta Neuropathologica Communications 3 (1): 22. doi:10.1186/s40478-015-0201-7. http://dx.doi.org/10.1186/s40478-015-0201-7.
    Description: Introduction: Medulloblastoma (MB) is the most frequent malignant brain tumor in children. Four subgroups with distinct genetic, epigenetic and clinical characteristics have been identified. Survival remains particularly poor in patients with Group 3 tumors harbouring a MYC amplification. We herein explore the molecular mechanisms and translational implications of class I histone deacetylase (HDAC) inhibition in MYC driven MBs. Material and Methods Expression of HDACs in primary MB subgroups was compared to normal brain tissue. A panel of MB cell lines, including Group 3 MYC amplified cell lines, were used as model systems. Cells were treated with HDAC inhibitors (HDACi) selectively targeting class I or IIa HDACs. Depletion of HDAC2 was performed. Intracellular HDAC activity, cellular viability, metabolic activity, caspase activity, cell cycle progression, RNA and protein expression were analyzed. Results: HDAC2 was found to be overexpressed in MB subgroups with poor prognosis (SHH, Group 3 and Group 4) compared to normal brain and the WNT subgroup. Inhibition of the enzymatic activity of the class I HDACs reduced metabolic activity, cell number, and viability in contrast to inhibition of class IIa HDACs. Increased sensitivity to HDACi was specifically observed in MYC amplified cells. Depletion of HDAC2 increased H4 acetylation and induced cell death. Simulation of clinical pharmacokinetics showed time-dependent on target activity that correlated with binding kinetics of HDACi compounds. Conclusions: We conclude that HDAC2 is a valid drug target in patients with MYC amplified MB. HDACi should cover HDAC2 in their inhibitory profile and timing and dosing regimen in clinical trials should take binding kinetics of compounds into consideration. Electronic supplementary material The online version of this article (doi:10.1186/s40478-015-0201-7) contains supplementary material, which is available to authorized users.
    Keywords: Medulloblastoma ; Hdac ; Hdac Inhibitor ; Hdac2 ; Myc
    ISSN: 2051-5960
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  • 4
    In: Neuro-Oncology, 2016, Vol. 18(suppl3), pp.iii110-iii110
    Keywords: Medicine;
    ISSN: 1522-8517
    E-ISSN: 1523-5866
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  • 5
  • 6
    In: Neuro-Oncology, 2018, Vol. 20(suppl2), pp.i155-i155
    Description: Identification of multiple distinct subtypes of pediatric brain tumors raises the need for more and better preclinical models reflecting these subtypes. Orthotopic patient-derived xenograft (PDX) models generated by injection of human tumor cells into the brain of NSG mice offer the unique possibility to test novel substances in primary patient tissue in an in vivo environment. Extensive molecular characterization of PDX and matching primary tumor/blood are needed to see how well the PDX represents the original disease, to learn about targetable oncogenic drivers in each model, and to establish or confirm predictive biomarkers. In an ongoing world-wide effort we have generated and fully characterized thus far 130 PDX models reflecting 22 distinct molecular subtypes of pediatric brain tumors. PDX models always retain their molecular subtype as assessed by DNA methylation analysis and in the vast majority of cases also the mutations and copy number alterations when compared to their primary tumors. Most aggressive tumors, such as those having MYC(N) amplifications, are overrepresented in the cohort, but also subtypes which have not been available for preclinical testing before due to lack of genetically engineered mouse models or suitable cell lines are included. All models and corresponding molecular data will become available for the community for preclinical research. Our repertoire of PDX models and corresponding molecular characterizations allow researchers to find the right models for their specific scientific questions. It provides an unprecedented resource to study tumor biology and paves the way for improving treatment strategies for children with malignant brain tumors.
    Keywords: Medicine;
    ISSN: 1522-8517
    E-ISSN: 1523-5866
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  • 7
    In: Neuro-Oncology, 2018, Vol. 20(suppl2), pp.i130-i130
    Description: High-risk medulloblastoma (MB) is a deadly disease with poor overall survival. Survivors suffer from severe treatment-associated morbidity. Patients with Group 3 MB with an amplification of MYC show particularly poor outcome. Therefore novel therapies tailored to this subgroup are urgently needed. We have previously shown that MYC amplified MB cell lines are highly susceptible to inhibition of class I histone deacetylases (HDACs), including HDAC2. We here explore the functional interaction of HDAC2 and MYC.
    Keywords: Medicine;
    ISSN: 1522-8517
    E-ISSN: 1523-5866
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  • 8
    In: Neuro-Oncology, 2017, Vol. 19(suppl6), pp.vi200-vi200
    Description: Pilocytic astrocytoma (PA) is the most frequent pediatric brain tumor. This single-pathway disease exhibits aberrant activation of the MAPK pathway driving the tumor into oncogene-induced senescence (OIS). OIS is proposed to be the source of the unstable however benign growth observed in PA patients. Senescence is thought to be regulated by the senescence-associated secretory phenotype (SASP) which comprises a variety of cytokines, growth factors and proteases. Markers of senescence have been detected in PA, but the functional relevance of the SASP and its relation to OIS in PA is unknown. The first patient-derived PA cell culture model DKFZ-BT66 was utilized for the characterization of OIS and the role of the SASP in PA. The model allows experimental switching between senescent and proliferating states by modulation of the p53/RB pathway. Both conditions were analyzed by gene-expression profiling (GEP), Western Blot, real-time qPCR, ELISA, cell counts and viability by automated trypan blue exclusion staining. A significant increase of the SASP could be detected by GEP in the OIS state of the PA cell line. Moreover, the OIS expression signature was associated with improved progression free survival in a cohort of n=112 PA patients. Upregulation of IL-6 and IL-1B, two representative SASP factors, could be demonstrated on mRNA and protein level in DKFZ-BT66 during OIS. Both cytokine receptors are expressed and activation of the respective pathways was confirmed. Activation of the IL-1 pathway led to decreased growth of proliferating PA cells. Overall, the novel primary PA tumor model provides functional evidence of the presence of OIS in PA and exhibits increased activity of the SASP during the senescent state. In order to find an explanation for the clinically observed spontaneous on/off growth behavior, current studies aim to investigate the disruption of the OIS-characteristic growth arrest by inhibition of inflammatory signaling pathways.
    Keywords: Medicine;
    ISSN: 1522-8517
    E-ISSN: 1523-5866
    Source: Oxford University Press
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  • 9
    In: Neuro-Oncology, 2018, Vol. 20(suppl2), pp.i106-i106
    Description: The main challenge in the clinical management of pilocytic astrocytoma (PA) is its unpredictable growth behavior. PA cells are driven into oncogene-induced senescence (OIS) by aberrant MAPK activation. In other senescence models OIS was shown to be regulated and maintained by the senescence-associated secretory phenotype (SASP). In this study, the first patient-derived cell culture model DKFZ-BT66 was used to show presence of the SASP in PA and to analyze its impact on OIS. This model allows for shifting between proliferation and senescence via doxycycline-inducible inhibition of the OIS-relevant p53/RB pathway. Both states were studied using gene-expression profiling (GEP), Western blot, qPCR, ELISA, and automated trypan blue exclusion staining. The GEP shows significant upregulation of SASP factors during OIS in DKFZ-BT66 cells. Conditioned medium of senescent DKFZ-BT66 cells is sufficient to induce growth arrest of proliferating DKFZ-BT66 cells. Upregulation of the SASP factors IL-1B and IL-6 was validated on mRNA and protein levels and both pathways are active during OIS. Stimulation of the IL-1 pathway reduces growth of proliferating DKFZ-BT66 cells. While pharmacological inhibition of single cytokines is not sufficient to overcome growth arrest during OIS, treatment with the anti-inflammatory drug dexamethasone induces regrowth of senescent cells. Overall, the primary PA model provides evidence of the presence of OIS in PA and exhibits increased activity of the SASP during senescence. Our data suggest that the SASP has an important impact on the growth regulation of senescent PA cells. Alteration of SASP factors may result in spontaneous regrowth of senescent PA tumors.
    Keywords: Medicine;
    ISSN: 1522-8517
    E-ISSN: 1523-5866
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  • 10
    In: Klinische Pädiatrie, 2018, Vol.230(06)
    In: Klinische Pädiatrie, 2018, Vol.230(06), pp.305-313
    Description: Central nervous system (CNS) tumors account for the highest mortality among pediatric malignancies. Accurate diagnosis is essential for optimal clinical management. The increasing use of molecular diagnostics has opened up novel possibilities for more precise classification of CNS tumors. We here report a single-institutional collection of pediatric CNS tumor cases that underwent a refinement or a change of diagnosis after completion of molecular analysis that affected clinical decision-making including the application of molecularly informed targeted therapies. 13 pediatric CNS tumors were analyzed by conventional histology, immunohistochemistry, and molecular diagnostics including DNA methylation profiling in 12 cases, DNA sequencing in 8 cases and RNA sequencing in 3 cases. 3 tumors had a refinement of diagnosis upon molecular testing, and 6 tumors underwent a change of diagnosis. Targeted therapy was initiated in 5 cases. An underlying cancer predisposition syndrome was detected in 5 cases. Although this case series, retrospective and not population based, has its limitations, insight can be gained regarding precision of diagnosis and clinical management of the patients in selected cases. Accuracy of diagnosis was improved in the cases presented here by the addition of molecular diagnostics, impacting clinical management of affected patients, both in the first-line as well as in the follow-up setting. This additional information may support the clinical decision making in the treatment of challenging pediatric CNS tumors. Prospective testing of the clinical value of molecular diagnostics is currently underway.
    Keywords: Brain tumor ; Molecular diagnostics ; Targeted therapy ; Cancer predisposition syndromes
    ISSN: 0300-8630
    E-ISSN: 1439-3824
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