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  • 1
    Keywords: brain ; CELLS ; tumor ; Germany ; PATHWAY ; PATHWAYS ; CLASSIFICATION ; SYSTEM ; SYSTEMS ; GENE ; GENES ; TUMORS ; PATIENT ; MECHANISM ; CONTRAST ; mechanisms ; FREQUENCY ; polymorphism ; POLYMORPHISMS ; VARIANTS ; IDENTIFICATION ; LESIONS ; WHITE-MATTER ; SERIES ; pathology ; NEOPLASTIC TRANSFORMATION ; molecular ; VARIANT ; MUTATIONAL ANALYSIS ; ALLELES ; DYSPLASIA ; epilepsy ; focal cortical dysplasia ; FOCAL EPILEPSIES ; GANGLIOGLIOMAS ; glio-neuronal lesion ; GLIONEURONAL TUMORS ; tuberous sclerosis ; TUBEROUS SCLEROSIS COMPLEX
    Abstract: Epilepsy-associated malformations of cortical development (MCDs) comprise a variety of dysplastic and neoplastic lesions of yet undetermined molecular pathology. Histopathologic similarities between MCDs and dysplastic brain lesions in the autosomal inherited neurocutaneous phacomatosis tuberous sclerosis (TSC), which affects the TSC1 and/or TSC2 genes, suggest common pathogenetic mechanisms. Previous studies revealed different alterations of TSC1 and TSC2 in epilepsy-associated malformations and glio-neuronal tumors despite histopathologic similarities. In order to examine current clinico-pathologic classification systems of cortical malformations on the molecular level, we carried out a mutational analysis of TSC1 and TSC2 in a series of surgical specimens obtained from patients with FCD without Taylor type balloon cells (FCDIIa; n = 20), architectural dysplasias (FCDI; n = 15), nodular cortical heterotopias (NCH; It = 4), and heterotopic white matter neurons (WMNH; It = 19). In FCDIIa, abundant genomic polymorphisms were detected in TSC2 (intron 4) but no allelic variants observed in exon 17 of TSCL This allelic distribution pattern is in contrast to findings in FCDI and WMNH but also to those previously reported in FCDIIb (Taylor's balloon cell type). The latter revealed increased frequencies of specific alleles only in TSCL The determination of characteristic molecular genetic alterations in specific epilepsy-associated malformations will support a comprehensive clinico-pathologic classification system and help to identify molecular pathways with potential pathogenetic relevance. Our work is supported by DFG (SFB TRB [AJB], DFG B1 42 1/1-1 [113]), BONFOR, and Deutsche Krebshilfe
    Type of Publication: Journal article published
    PubMed ID: 16042315
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  • 2
    Keywords: brain ; APOPTOSIS ; EXPRESSION ; SURVIVAL ; tumor ; Germany ; DISEASE ; MORTALITY ; PROTEIN ; RESOLUTION ; MICE ; TUMOR-NECROSIS-FACTOR ; NITRIC-OXIDE ; murine ; T-CELLS ; NUMBER ; RATES ; NECROSIS-FACTOR-ALPHA ; IMMUNE-RESPONSE ; CENTRAL-NERVOUS-SYSTEM ; pathology ; TNF-ALPHA ; protein expression ; TNF ; FACTOR-ALPHA ; SYNTHASE ; development ; REACTIVE OXYGEN ; PHASE ; NITRIC-OXIDE-SYNTHASE ; NECROSIS-FACTOR ; TUMOR NECROSIS FACTOR ; nitric oxide synthase ; brain abscess ; INTRACEREBRAL IMMUNE-RESPONSE ; NEUTROPHIL APOPTOSIS ; RECEPTOR-TYPE 1 ; Staphylococcus aureus ; TOXOPLASMA ENCEPHALITIS
    Abstract: Tumor necrosis factor-alpha (TNF-alpha) is a central mediator of the immune response to pathogens, but may also exert neurotoxic effects, thereby contributing to immunopathology. To define the role of TNF during the course of brain abscess, TNF-deficient (TNF0/0) truce were stereotaxically infected with Staphylococcus (S.) aureus-laden agarose beads. In comparison to 100% survival of wild type (WT) mice, TNF0/0 mice displayed high mortality rates (54%) in the initial phase of abscess development as well as significantly increased morbidity in the course of the disease. The worse clinical outcome was due to an increased intracerebral (i.e.) bacterial load in TNF0/0 mice as compared to WT mice. The impaired control of S. aureus was associated with reduced inductible nitric oxide synthase (iNOS) mRNA and protein expression in TNF0/0 mice. Similarly, numbers of inflammatory leukocytes, cytokine expression of IL-6, IL-12p40, IFNgamma, IL-1beta mRNA, and brain edema were significantly increased in TNF0/0 mice as compared to WT animals. In addition, resolution of i.e. infiltrates was delayed in TNF0/0 mice correlating with reduced apoptosis of inflammatory leukocytes and formation of a fibrous abscess capsule. Collectively, these data demonstrate that TNF is of key importance for the control of S. aureus-induced brain abscess and regulates the ensuing host immune response
    Type of Publication: Journal article published
    PubMed ID: 15715082
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  • 3
    Keywords: ANGIOGENESIS ; CELLS ; EXPRESSION ; ENDOTHELIAL GROWTH-FACTOR ; INHIBITION ; POPULATION ; PROTEIN ; mechanisms ; DOWN-REGULATION ; HYPERMETHYLATION ; MALIGNANT GLIOMAS ; astrocytoma ; SUBTYPES ; PROMOTER METHYLATION ; GLIOBLASTOMA ; AKAP12 ; Gravin ; SSeCKS ; SSECKS/GRAVIN/AKAP12
    Abstract: The scaffold protein A-kinase anchor protein 12 (AKAP12) exerts tumor suppressor activity and is downregulated in several tumor entities. We characterized AKAP12 expression and regulation in astrocytomas, including pilocytic and diffusely infiltrating astrocytomas. We examined 194 human gliomas and 23 normal brain white matter samples by immunohistochemistry or immunoblotting for AKAP12 expression. We further performed quantitative methylation analysis of the AKAP12 promoter by MassARRAY (R) of normal brain, World Health Organization (WHO) grade I to IV astrocytomas, and glioma cell lines. Our results show that AKAP12 is expressed in a perivascular distribution in normal CNS, strongly upregulated in tumor cells in pilocytic astrocytomas, and weakly expressed in diffuse astrocytomas of WHO grade II to IV. Methylation analyses revealed specific hypermethylation of AKAP12 alpha promoter in WHO grade II to IV astrocytomas. Restoration experiments using 5-aza-2'-deoxycytidine in primary glioblastoma cells decreased AKAP12 alpha promoter methylation and markedly increased AKAP12 alpha mRNA levels. In summary, we demonstrate that AKAP12 is differentially expressed in human astrocytomas showing high expression in pilocytic but low expression in diffuse astrocytomas of all WHO-grades. Our results further indicate that epigenetic mechanisms are involved in silencing AKAP12 in diffuse astrocytomas; however, a tumor suppressive role of AKAP12 in distinct astrocytoma subtypes remains to be determined
    Type of Publication: Journal article published
    PubMed ID: 24042196
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  • 4
    Keywords: EXPRESSION ; EPIDEMIOLOGY ; TUMORS ; DUPLICATION ; CENTRAL-NERVOUS-SYSTEM ; TRANSCRIPTS ; LOW-GRADE GLIOMAS ; RAF ; TARGETED THERAPY ; MAPK PATHWAY ACTIVATION
    Abstract: Pilocytic astrocytomas (PAs) are increasingly tested for KIAA1549-BRAF fusions. We used reverse transcription polymerase chain reaction for the 3 most common KIAA1549-BRAF fusions, together with BRAF V600E and histone H3.3 K27M analyses to identify relationships of these molecular characteristics with clinical features in a cohort of 32 PA patients. In this group, the overall BRAF fusion detection rate was 24 (75%). Ten (42%) of the 24 had the 16-9 fusion, 8 (33%) had only the 15-9 fusion, and 1 (4%) of the patients had only the 16-11 fusion. In the PAs with only the 15-9 fusion, 1 PA was in the cerebellum and 7 were centered in the midline outside of the cerebellum, that is, in the hypothalamus (n = 4), optic pathways (n = 2), and brainstem (n = 1). Tumors within the cerebellum were negatively associated with fusion 15-9. Seven (22%) of the 32 patients had tumor-related deaths and 25 of the patients (78%) were alive between 2 and 14 years after initial biopsy. Age, sex, tumor location, 16-9 fusion, and 15-9 fusion were not associated with overall survival. Thus, in this small cohort, 15-9 KIAA1549-BRAF fusion was associated with midline PAs located outside of the cerebellum; these tumors, which are generally difficult to resect, are prone to recurrence.
    Type of Publication: Journal article published
    PubMed ID: 26222501
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  • 5
    Keywords: proliferation ; SYSTEM ; DISEASE ; PROTEIN ; MICE ; PATIENT ; MARKER ; ANTIGEN ; ANTIGENS ; T cell ; T cells ; T-CELL ; T-CELLS ; culture ; antibodies ; antibody ; MOUSE ; NERVOUS-SYSTEM ; LESIONS ; NUMBER ; COMPONENT ; DAMAGE ; cytoskeleton ; NETHERLANDS ; CD8(+) ; CENTRAL-NERVOUS-SYSTEM ; pathology ; AMYOTROPHIC-LATERAL-SCLEROSIS ; MULTIPLE-SCLEROSIS ; INTERFERON-GAMMA ; inflammation ; CD4(+) T-CELLS ; AUTOIMMUNE ENCEPHALOMYELITIS ; SERUM ; AUTOIMMUNITY ; IMMUNIZATION ; CYTOKINE ; RECOMBINANT ; RE ; SERUM ANTIBODIES ; LEVEL ; multiple sclerosis ; USA ; animal model ; central nervous system ; DEGENERATION ; EXPERIMENTAL ALLERGIC ENCEPHALOMYELITIS ; correlates ; SENSORY NEURONOPATHY ; axonal damage ; MS LESIONS ; neurofilament light ; PROGRESSIVE MULTIPLE-SCLEROSIS ; spastic paresis
    Abstract: Axonal damage is the major cause of irreversible neurologic disability in patients with multiple sclerosis. Although axonal damage correlates with antibodies against neurotilament light (NF-L) protein, a major component of the axonal cytoskeleton, the possible pathogenic role of autoirnmunity to axonal antigens such as NF-L has so far been ignored. Here we show that Biozzi ABH mice immunized with NF-L protein develop neurologic disease characterized by spastic paresis and paralysis concomitant with axonal degeneration and inflammation primarily in the dorsal column of the spinal cord. The inflammatory central nervous system lesions were dominated by F4/80' macrophages/microglia and relatively low numbers of CD4(+) and CD8(+) T-cells. In splenocyte cultures, proliferation to NF-L was observed in CD4(+) T-cells accompanied by the production of the proinflammatory cytokine interferon-gamma. Elevated levels of circulating antibodies recognizing recombinant mouse NF-L were present in the serum, and immunoglobulin deposits were observed within axons in spinal cord lesions of mice exhibiting clinical disease. These data provide evidence that autoimmunity to NF-L protein induces axonal degeneration and clinical neurologic disease in mice, indicating that autoimmunity to axonal antigens, as described in multiple sclerosis, may be pathogenic rather than acting merely as a surrogate marker for axonal degeneration
    Type of Publication: Journal article published
    PubMed ID: 17413320
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  • 6
    Keywords: TUMOR-CELLS ; INHIBITION ; ACTIVATION ; resistance ; CANCER-CELLS ; MULTIPLE-MYELOMA ; MEDIATED APOPTOSIS ; CHEMOTHERAPEUTIC DRUGS ; HEPATOCELLULAR-CARCINOMA CELLS ; ANTICANCER THERAPY
    Abstract: A meningioma is the most common primary intracranial tumor in adults. Here, we investigated the therapeutic potential of the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in 37 meningiomas. Freshly isolated primary meningioma cells were treated with TRAIL with or without different sensitizing protocols, and apoptotic cell death was then quantified. Mechanisms of TRAIL sensitization were determined by a combination of Western blotting, flow cytometry, receptor complex immunoprecipitation, and siRNA-mediated knockdown experiments. Tumor necrosis factor-related apoptosis-inducing ligand receptor expression was analyzed using immunohistochemistry and quantified by an automated software-based algorithm. Primary tumor cells from 11 (29.7%) tumor samples were sensitive to TRAIL-induced apoptosis, 12 (32.4%) were intermediate TRAIL resistant, and 14 (37.8%) were completely TRAIL resistant. We tested synergistic apoptosis-inducing cotreatment strategies and determined that only the proteasome inhibitor bortezomib potently enhanced expression of the TRAIL receptors TRAIL-R1 and/or TRAIL-R2, the formation of the TRAIL death-inducing signaling complex, and activation of caspases; this treatment resulted in sensitization of all TRAIL-resistant meningioma samples to TRAIL-induced apoptosis. Bortezomib pretreatment induced NOXA expression and downregulated c-FLIP, neither of which caused the TRAIL-sensitizing effect. Native TRAIL receptor expression could not predict primary TRAIL sensitivity. This first report on TRAIL sensitivity of primary meningioma cells demonstrates that TRAIL/bortezomib cotreatment may represent a novel therapeutic option for meningiomas.
    Type of Publication: Journal article published
    PubMed ID: 25289891
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  • 7
    Abstract: Cancer stem cells may mediate therapy resistance and recurrence in various types of cancer, including glioblastoma. Cancer stemlike cells can be isolated from long-term cancer cell lines, including glioma lines. Using sphere formation as a model for cancer cell stemness in vitro, we derived sphere cultures from SMA-497, SMA-540, SMA-560, and GL-261 glioma cells. Gene expression and proteomics profiling demonstrated that sphere cultures uniformly showed an elevated expression of stemness-associated genes, notably including CD44. Differences in neural lineage marker expression between nonsphere and sphere cultures were heterogeneous except for a uniform reduction of beta-III-tubulin in sphere cultures. All sphere cultures showed slower growth. Self-renewal capacity was influenced by medium conditions but not nonsphere versus sphere culture phenotype. Sphere cultures were more resistant to irradiation, whereas both nonsphere and sphere cultures were highly resistant to temozolomide. Nonsphere cells formed more aggressive tumors in syngeneic mice than sphere cells in all models except SMA-560. There were no major differences in vascularization or infiltration by T cells or microglia/macrophages between nonsphere and sphere cell-derived tumors implanted in syngeneic hosts. Together, these data indicate that mouse glioma cell lines may be induced in vitro to form spheres that acquire features of stemness, but they do not exhibit a uniform biologic phenotype, thereby challenging the view that they represent a superior model system.
    Type of Publication: Journal article published
    PubMed ID: 25289892
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  • 8
    Abstract: Dysembryoplastic neuroepithelial tumors (DNET) are considered to be rare, benign, and associated with chronic epilepsy. We present the case of a 28-year-old man with a history of epilepsy since age 12. Surgery of an occipital cortical lesion in 2009 revealed a DNET. Five years later, a recurrent tumor at the edge of the resection cavity was removed, and the tissue underwent an intensive diagnostic workup. The first tumor was unequivocally characterized as a DNET, but neuropathological diagnostics of the recurrent tumor revealed a glioblastoma. After 6 months, another recurrent tumor was detected next to the location of the original tumor, and this was also resected. An Illumina 450 K beadchip methylation array was performed to characterize all of the tumors. The methylation profile of these tumors significantly differed from other glioblastoma and epilepsy-associated tumor profiles and revealed a DNET-like methylation profile. Thus, molecular characterization of these recurrent tumors suggests malignant transformation of a previously benign DNET. We found increased copy number changes in the recurrent DNET tumors after malignant transformation. Modern high-throughput analysis adds essential molecular information in addition to standard histopathology for proper identification of rare brain tumors that present with an unusual clinical course.
    Type of Publication: Journal article published
    PubMed ID: 26921879
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  • 9
    Abstract: Glioblastomas (GBMs) are malignant brain tumors that can be divided into different molecular subtypes based on genetics, global gene expression, and methylation patterns. Among these subgroups, "IDH" GBMs carry mutations within IDH1 or IDH2 The "K27" and "G34" subgroups are characterized by distinct mutations within Histone 3 (H3). These subtypes can be identified by sequencing methods and are particularly found in younger patients. To determine whether the molecular subtypes correlate with distinct histological features among the diverse histologic patterns of GBM, we performed a blinded assessment of the histology of GBMs of 77 patients 〈/=30 years old at the time of biopsy. The tumors were of the following molecular subtypes: IDH (n = 12), H3 K27M (n = 25), H3 G34R (n = 12), or no IDH/H3 mutations (n = 28). Of IDH-mutated cases, 75% had microcystic features or gemistocytic tumor cells. K27 GBMs had higher cell densities and pronounced nuclear pleomorphism, with 28% harboring tumor giant cells. All G34 GBMs had variable extents of a poorly differentiated/primitive neuroectodermal tumor-like morphology. GBMs without IDH/H3 mutations had foci of epitheliod-appearing cells. Thus, molecular GBM subgroups are associated with distinct histological patterns, suggesting that morphological features reflect the specific underlying molecular genetic abnormalities.
    Type of Publication: Journal article published
    PubMed ID: 26975364
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  • 10
    Abstract: Atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system is a highly malignant, pediatric brain tumor typically arising de novo. Inactivation of SMARCB1 is a defining molecular event. We present here a rare case of an adult (35 years) low-grade SMARCB1-deleted brain tumor with transition into prototypical AT/RT over 14 years. Molecular analysis was performed for 3 tumor presentations including copy number analysis, DNA methylation analysis (450k), and whole exome sequencing. We detected the identical somatic SMARCB1 deletion at all 3 time-points. In an unsupervised hierarchical clustering of methylation data together with 127 reference cases comprising 9 brain tumor classes all 3 manifestations clustered with AT/RT. Exome sequencing revealed an increase of mutational burden over time. The acquired mutations and additional copy number changes did not affect known cancer genes. In conclusion, we demonstrate molecular changes associated with histological and clinical transition of a low-grade brain tumor to an adult AT/RT. Our observation of a stable disease course for nearly 10 years in a tumor with SMARCB1 loss and an AT/RT-like DNA methylation profile indicates that caution may be required in the diagnostic interpretation of such findings in adult patients.
    Type of Publication: Journal article published
    PubMed ID: 28789476
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