Andreas Peyrl

Antiangiogenic metronomic therapy for children with recurrent embryonal brain tumors

Median survival time of recurrent embryonal brain tumors is short regardless of salvage chemotherapy used. An evolving alternative approach to conventional chemotherapy is to target neovascularization by interfering with tumor angiogenesis at various levels.

Aberrant expression of signaling‐related proteins 14‐3‐3 gamma and RACK1 in fetal Down Syndrome brain (trisomy 21)

Although Down Syndrome (DS, trisomy 21) is the most frequent isolated cause of mental retardation, information on brain protein expression and in particular protein expression of signaling‐related proteins is limited. Impaired signaling in DS involving different signaling systems has been proposed and the availability of fetal brain along with recent proteome technologies unambiguously identifying individual brain proteins made us study individual signaling factors in the brain. We studied fetal brain cortex of controls (n = 7) and DS (n = 9) from early second trimester of gestation by two‐dimensional gel electrophoresis with subsequent matrix‐assisted laser/desorption ionization (MALDI) identification followed by quantification with specific software. Four 14‐3‐3 protein isoforms, mitogen‐activated protein kinase 1, receptor for activited kinase 1 (RACK1), constitutive photomorphogenesis (COP9) complex subunit 4 and cAMP‐dependent protein kinase type II have been identified. Quantification showed that protein 14‐3‐3 gamma (means ± standard deviation of controls: 10.18 ± 2.30 and of DS 4.20 ± 1.19) and two spots assigned to RACK1 (controls spot 1: 4.15 ± 2.45 and DS 1.95 ± 0.93; controls spot 2: 5.08 ± 2.4 vs. DS: 2.56 ± 1.19) were significantly decreased in DS cortex. Reduced 14‐3‐3 gamma may represent impaired neuronal differentiation, synaptic plasticity and impaired signaling by PKC and Raf while decreased RACK1 (anchoring protein receptor for activated C‐kinase) may reflect or generate deranged beta‐II‐ protein kinease C (PKC) function with the putative biological meaning of aberrant migration and neuritic outgrowth in DS early in life.

Atypical teratoid rhabdoid tumor: improved long-term survival with an intensive multimodal therapy and delayed radiotherapy. The Medical University of Vienna Experience 1992-2012.

Atypical teratoid rhabdoid tumors (ATRTs) are recently defined highly aggressive embryonal central nervous system tumors with a poor prognosis and no definitive guidelines for treatment. We report on the importance of an initial correct diagnosis and disease‐specific therapy on outcome in 22 consecutive patients and propose a new treatment strategy. From 1992 to 2012, nine patients initially diagnosed correctly as ATRT (cohort A, median age 24 months) were treated according to an intensive multimodal regimen (MUV‐ATRT) consisting of three 9‐week courses of a dose‐dense regimen including doxorubicin, cyclophosphamide, vincristine, ifosfamide, cisplatin, etoposide, and methotrexate augmented with intrathecal therapy, followed by high‐dose chemotherapy (HDCT) and completed with local radiotherapy. Thirteen patients were treated differently (cohort B, median age 30 months) most of whom according to protocols in use for their respective diagnoses. As of July 2013, 5‐year overall survival (OS) and event‐free survival (EFS) for all 22 consecutive patients was 56.3 ± 11.3% and 52.9 ± 11.0%, respectively. For MUV‐ATRT regimen‐treated patients (cohort A) 5‐year OS was 100% and EFS was 88.9 ± 10.5%. For patients treated differently (cohort B) 5‐year OS and EFS were 28.8 ± 13.1%. All nine MUV‐ATRT regimen‐treated patients are alive for a median of 76 months (range: 16–197), eight in first complete remission. Our results compare favorably to previously published data. The drug combination and sequence used in the proposed MUV‐ATRT regimen appear to be efficacious in preventing early relapses also in young children with M1–M3 stage disease allowing postponement of radiotherapy until after HDCT.

Feasibility and tolerability of bevacizumab in children with primary CNS tumors

Bevacizumab, an antibody to the vascular endothelial growth factor, has demonstrated anti‐cancer activity in a number of solid tumors. Fear of intratumoral hemorrhage, however, has slowed its introduction into the treatment of central nervous system (CNS) tumors. Currently, only a small number of children with gliomas received bevacizumab.

Proteomic characterization of the human cortical neuronal cell line HCN-2.

Neuronal marker proteins are widely used for characterization and identification of normal and tumor tissue of the central nervous system, but the most commonly used neuronal markers have inherent methodological problems. We used a proteomic approach with two-dimensional (2-D) gel electrophoresis and subsequent MALDI identification to identify possible new marker proteins in the human cortical neuronal cell line HCN-2. We found 14 proteins that previously were predicted only on the basis of open reading frames from mRNA sequences or DNA. We could unambiguously identify the following proteins: Bab55091, BK65A6.2 (Novel Sushi Domain (Scr repeat), glucosidase II alpha subunit, glucosidase II precursor (KIAA0088 protein), HSPC108, hypothetical 35.8 kDa protein, hypothetical 40.7 KDA protein, hypothetical 49.4 kDa protein, leucine-zipper protein FKSG13, lysophospholipase homolog, mitofilin (fragment), P1.11659_4, reticulocabin precursor and one unknown protein for MGC:10432. We could prove the existence of these 14 proteins in the human neuron, extending the list of proteins with neuronal expression and identify possible new candidate marker proteins.

Pharmacokinetics and Safety of Intrathecal Liposomal Cytarabine in Children Aged <3 Years

AbstractBackground and objective: Liposomal cytarabine (DepoCyte®) is a slow-release formulation for intrathecal application, ensuring prolonged drug exposure. Although there is an urgent need for new treatment options for infants with leptomeningeal dissemination of a malignant brain tumour, there are no clinical and pharmacokinetic data available on this drug for children aged <3 years. The objective of this pilot study was to determine the feasibility, safety and pharmacokinetics of cytarabine after intrathecal administration of liposomal cytarabine 25 mg in patients aged <3 years. Patients and methods: Six male patients with a mean age of 21 months and CNS primitive neuroectodermal tumours (n = 3) or atypical teratoid/rhabdoid tumours (n = 3) were included. Liposomal cytarabine (25 mg) was administered intraventricularly. One patient also received the drug by lumbar puncture. Dexamethasone was used concomitantly for 3–5 days to prevent arachnoiditis. Cerebrospinal fluid (CSF) and plasma samples were collected before administration of liposomal cytarabine and 1 hour, 12 hours, 24 hours, 1 week and 2 weeks post-dosing. Noncompartmental pharmacokinetic analysis of CSF and plasma was performed. Results: Liposomal cytarabine was generally well tolerated; only grade 2 headache occurred in one patient. After intraventricular administration of cytarabine 25 mg, free and encapsulated drug concentrations above the cytotoxic drug level of 0.1 μg/mL were detectable in the CSF for at least 7 days and up to 14 days post-dosing. The average elimination half-lives were 56.7 hours for encapsulated cytarabine and 59.3 hours for free cytarabine. After intralumbar administration, the elimination half-life of free cytarabine, measured in the ventricular CSF during two courses in one patient, was significantly shorter (32.7 hours). Conclusion: Application of liposomal cytarabine with concomitant dexamethasone appears to be safe and well tolerated in children aged <3 years. Drug exposure in infants aged <3 years after an intraventricular dose of 25 mg is comparable to that after administration of 50 mg in adult patients and 35 mg in older children.

Embryonal tumor with abundant neuropil and true rosettes (ETANTR) with loss of morphological but retained genetic key features during progression

Embryonal tumor with abundant neuropil and true rosettes (ETANTR) is a recently recognized, rare embryonal CNS tumor, which predominantly occurs in young children and is associated with a highly aggressive disease course [1–3, 5–8, 13, 14, 18, 19, 23]. The histopathological diagnosis of ETANTR is based on the presence of primitive neuroectodermal tumor cells forming distinct multilayered ‘ependymoblastic’ rosettes and characteristic neuropil islands. Recently, genome-wide analyses have revealed a novel amplification at 19q13.42 [16, 19], which is meanwhile considered the genetic hallmark of ETANTR [13, 16]. The characteristic clinical, morphological, and genetic features support the concept of a distinct CNS PNET variant and suggest its introduction to the WHO classification of Tumors of the Central Nervous System [17]. As the amplification at 19q13.42 has also been found in the vast majority of ependymoblastomas analyzed to date [13, 16], the common genetic background suggests the fusion of these two tumor types to a single entity. Herein, we report for the first time the evolution of morphological features and genetic aberrations during the disease course in a patient with ETANTR. A 33-monthold girl presented with a 6-month history of episodic headaches, increased head circumference and mild gait disturbance. Magnetic resonance (MR) imaging showed a 9.6 9 8.6 9 11.7 cm left parieto-occipital, space-occupying, partly cystic lesion displaying T1-weighted hypoto isointense signals (Fig. 1a) with cerebrospinal fluid-intense cysts on FLAIR sequence (Fig. 1b), and marked choline/ creatine increase as a sign of cell proliferation on single voxel spectroscopy (Fig. 1c). Near-total surgical resection was performed. Histopathology revealed a primitive neuroectodermal tumor with highly cellular areas. Furthermore, hypocellular neuropil islands and multilayered rosettes were

Tumor stabilization under treatment with imatinib in progressive hypothalamic‐chiasmatic glioma

Hypothalamic‐chiasmatic gliomas (HCG) account for up to 20% of tumors in patients under the age of 3 years. While most children respond to chemotherapy, alternative treatment approaches are needed for those with progressive disease refractory to chemotherapy.

Telomerase activation in posterior fossa group A ependymomas is associated with dismal prognosis and chromosome 1q gain

Background Ependymomas account for up to 10% of childhood CNS tumors and have a high rate of tumor recurrence despite gross total resection. Recently, classification into molecular ependymoma subgroups has been established, but the mechanisms underlying the aggressiveness of certain subtypes remain widely enigmatic. The aim of this study was to dissect the clinical and biological role of telomerase reactivation, a frequent mechanism of cancer cells to evade cellular senescence, in pediatric ependymoma. Methods We determined telomerase enzymatic activity, hTERT mRNA expression, promoter methylation, and the rs2853669 single nucleotide polymorphism located in the hTERT promoter in a well-characterized cohort of pediatric intracranial ependymomas. Results In posterior fossa ependymoma group A (PF-EPN-A) tumors, telomerase activity varied and was significantly associated with dismal overall survival, whereas telomerase reactivation was present in all supratentorial RelA fusion-positive (ST-EPN-RELA) ependymomas. In silico analysis of methylation patterns showed that only these two subgroups harbor hypermethylated hTERT promoters suggesting telomerase reactivation via epigenetic mechanisms. Furthermore, chromosome 1q gain, a well-known negative prognostic factor, was strongly associated with telomerase reactivation in PF-EPN-A. Additional in silico analyses of gene expression data confirmed this finding and further showed enrichment of the E-twenty-six factor, Myc, and E2F target genes in 1q gained ependymomas. Additionally, 1q gained tumors showed elevated expression of ETV3, an E-twenty-six factor gene located on chromosome 1q. Conclusion Taken together we describe a subgroup-specific impact of telomerase reactivation on disease progression in pediatric ependymoma and provide preliminary evidence for the involved molecular mechanisms.

Developmental and oncogenic programs in H3K27M gliomas dissected by single-cell RNA-seq

The cellular composition of H3K27M gliomas Diffuse midline gliomas with histone H3 lysine27-to-methionine mutations (H3K27M-glioma) are an aggressive type of childhood cancer with few options for treatment. Filbin et al. used a single-cell sequencing approach to study the oncogenic programs, genetics, and cellular hierarchies of H3K27M-glioma. Tumors were mainly composed of cells resembling oligodendrocyte precursor cells, whereas differentiated malignant cells were a smaller fraction. In comparison with other gliomas, these cancers had distinct oncogenic programs and stem cell–like profiles that contributed to their stable tumor-propagating potential. The analysis also identified a lineage-specific marker that may be useful in developing therapies. Science, this issue p. 331 Single-cell analyses of H3K27M glioma defines a putative developmental hierarchy that differs from other gliomas. Gliomas with histone H3 lysine27-to-methionine mutations (H3K27M-glioma) arise primarily in the midline of the central nervous system of young children, suggesting a cooperation between genetics and cellular context in tumorigenesis. Although the genetics of H3K27M-glioma are well characterized, their cellular architecture remains uncharted. We performed single-cell RNA sequencing in 3321 cells from six primary H3K27M-glioma and matched models. We found that H3K27M-glioma primarily contain cells that resemble oligodendrocyte precursor cells (OPC-like), whereas more differentiated malignant cells are a minority. OPC-like cells exhibit greater proliferation and tumor-propagating potential than their more differentiated counterparts and are at least in part sustained by PDGFRA signaling. Our study characterizes oncogenic and developmental programs in H3K27M-glioma at single-cell resolution and across genetic subclones, suggesting potential therapeutic targets in this disease.