Noninvasive positron emission tomography and fluorescence imaging of CD133+ tumor stem cells.

A technology that visualizes tumor stem cells with clinically relevant tracers could have a broad impact on cancer diagnosis and treatment. The AC133 epitope of CD133 currently is one of the best-characterized tumor stem cell markers for many intra- and extracranial tumor entities. Here we demonstrate the successful noninvasive detection of AC133(+) tumor stem cells by PET and near-infrared fluorescence molecular tomography in subcutaneous and orthotopic glioma xenografts using antibody-based tracers.

Antiproliferative efficacies but minor drug transporter inducing effects of paclitaxel, cisplatin, or 5-fluorouracil in a murine xenograft model for head and neck squamous cell carcinoma.

Drug-induced multidrug resistance (MDR) has been linked to overexpression of drug transporting proteins in head and neck squamous cell carcinoma (HNSCC) in vitro. The aim of this work was to reassess these findings in a murine xenograft model. NOD-SCID mice xenotransplanted with 10 (6) HNO97 cells were treated for four consecutive weeks with weekly paclitaxel, biweekly cisplatin (both intraperitoneal), or 5-fluorouracil (5-FU, administered by osmotic pump).

Expansive growth of two glioblastoma stem-like cell lines is mediated by bFGF and not by EGF.

Background: Patient-derived glioblastoma (GBM) stem-like cells (GSCs) represent a valuable model for basic and therapeutic research. GSCs are usually propagated in serum-free Neural Basal medium supplemented with bFGF and EGF. Yet, the exact influence of these growth factors on GSCs is still unclear.

Generation of “LYmph Node Derived Antibody Libraries” (LYNDAL) for selecting fully human antibody fragments with therapeutic potential.

The development of efficient strategies for generating fully human monoclonal antibodies with unique functional properties that are exploitable for tailored therapeutic interventions remains a major challenge in the antibody technology field. Here, we present a methodology for recovering such antibodies from antigen-encountered human B cell repertoires. As the source for variable antibody genes, we cloned immunoglobulin G (IgG)-derived B cell repertoires from lymph nodes of 20 individuals undergoing surgery for head and neck cancer.

Distribution of TERT promoter mutations in pediatric and adult tumors of the nervous system.

Hot spot mutations in the promoter region of telomerase reverse transcriptase (TERT) have recently been described in several human tumor entities. These mutations result in an upregulation of the telomerase complex activity and thus constitute a relevant mechanism for immortalization of tumor cells. Knowledge of the TERT promoter status in tumors is likely to be of interest for molecular classification and as a potential target for therapy.

AKT1E17K mutations cluster with meningothelial and transitional meningiomas and can be detected by SFRP1 immunohistochemistry.

The activating E17K mutation in the AKT1 gene has been detected in several tumor entities. Currently several clinical studies with specific AKT1 inhibitors are under way. To determine whether AKT1 mutations are involved in human tumors of the nervous system, we examined a series of 1,437 tumors including 391 primary intracranial brain tumors and 1,046 tumors of the coverings of the central and peripheral nervous system.

The chromatin remodeler CHD7 regulates adult neurogenesis via activation of SoxC transcription factors.

Chromatin factors that regulate neurogenesis in the central nervous system remain to be explored. Here, we demonstrate that the chromatin remodeler chromodomain-helicase-DNA-binding protein 7 (CHD7), a protein frequently mutated in human CHARGE syndrome, is a master regulator of neurogenesis in mammalian brain. CHD7 is selectively expressed in actively dividing neural stem cells (NSCs) and progenitors.

Recurrent somatic alterations of FGFR1 and NTRK2 in pilocytic astrocytoma.

Pilocytic astrocytoma, the most common childhood brain tumor, is typically associated with mitogen-activated protein kinase (MAPK) pathway alterations. Surgically inaccessible midline tumors are therapeutically challenging, showing sustained tendency for progression and often becoming a chronic disease with substantial morbidities. Here we describe whole-genome sequencing of 96 pilocytic astrocytomas, with matched RNA sequencing (n = 73), conducted by the International Cancer Genome Consortium (ICGC) PedBrain Tumor Project.

BCAT1 promotes cell proliferation through amino acid catabolism in gliomas carrying wild-type IDH1.

Here we show that glioblastoma express high levels of branched-chain amino acid transaminase 1 (BCAT1), the enzyme that initiates the catabolism of branched-chain amino acids (BCAAs). Expression of BCAT1 was exclusive to tumors carrying wild-type isocitrate dehydrogenase 1 (IDH1) and IDH2 genes and was highly correlated with methylation patterns in the BCAT1 promoter region. BCAT1 expression was dependent on the concentration of α-ketoglutarate substrate in glioma cell lines and could be suppressed by ectopic overexpression of mutant IDH1 in immortalized human astrocytes, providing a link between IDH1 function and BCAT1 expression.

Meningeal hemangiopericytoma and solitary fibrous tumors carry the NAB2-STAT6 fusion and can be diagnosed by nuclear expression of STAT6 protein.

Non-central nervous system hemangiopericytoma (HPC) and solitary fibrous tumor (SFT) are considered by pathologists as two variants of a single tumor entity now subsumed under the entity SFT. Recent detection of frequent NAB2-STAT6 fusions in both, HPC and SFT, provided additional support for this view. On the other hand, current neuropathological practice still distinguishes between HPC and SFT.

Lessons we learned from high-throughput and top-down systems biology analyses about glioma stem cells.

A growing body of evidence suggests that glioma stem cells (GSCs) account for tumor initiation, therapy resistance, and the subsequent regrowth of gliomas. Thus, continuous efforts have been undertaken to further characterize this subpopulation of less differentiated tumor cells. Although we are able to enrich GSCs, we still lack a comprehensive understanding of GSC phenotypes and behavior.

Minor role of pregnane-x-receptor for acquired multidrug resistance in head and neck squamous cell carcinoma in vitro.

Purpose: Acquired multidrug resistance (MDR) has been linked to overexpression of drug-metabolising and transporting proteins mediated by pregnane-x-receptor (PXR). The aim of this work was to establish the relevance of PXR for MDR in head and neck squamous cell carcinoma (HNSCC).

Methods: Using eight HNSCC cell lines, we determined the efficacy of paclitaxel, cisplatin and 5-fluorouracil (5-FU) via proliferation assays and determined the expression and activity of PXR through quantitative real-time polymerase chain reaction, western blotting and luciferase-based reporter gene assay.

Secretory meningiomas are defined by combined KLF4 K409Q and TRAF7 mutations.

Meningiomas are among the most frequent intracranial tumors. The secretory variant of meningioma is characterized by glandular differentiation, formation of intracellular lumina and pseudopsammoma bodies, expression of a distinct pattern of cytokeratins and clinically by pronounced perifocal brain edema. Here we describe whole-exome sequencing analysis of DNA from 16 secretory meningiomas and corresponding constitutional tissues.

Specific elimination of CD133+ tumor cells with targeted oncolytic measles virus.

Tumor-initiating cells (TIC) are critical yet evasive targets for the development of more effective antitumoral strategies. The cell surface marker CD133 is frequently used to identify TICs of various tumor entities, including hepatocellular cancer and glioblastoma. Here, we describe oncolytic measles viruses (MV) retargeted to CD133.

Natural HLA class I ligands from glioblastoma: extending the options for immunotherapy.

Glioblastoma multiforme is the most frequent and most malignant primary brain tumor with poor prognosis despite surgical removal and radio-chemotherapy. In this setting, immunotherapeutical strategies have great potential, but the reported repertoire of tumor associated antigens is only for HLA-A 02 positive tumors. We describe the first analysis of HLA-peptide presentation patterns in HLA-A 02 negative glioma tissue combined with gene expression profiling of the tumor samples by oligonucleotide microarrays.

Resistance to hypoxia-induced, BNIP3-mediated cell death contributes to an increase in a CD133-positive cell population in human glioblastomas in vitro.

In addition to intrinsic regulatory mechanisms, brain tumor stemlike cells (BTSCs), a small subpopulation of malignant glial tumor-derived cells, are influenced by environmental factors. Previous reports showed that lowering oxygen tension induced an increase of BTSCs expressing CD133 and other stem cell-related genes and more pronounced clonogenic capacity in vitro. We investigated the mechanisms responsible for hypoxia-dependent induction of CD133-positive BTSCs in glioblastomas.

Enzymatic assay for quantitative analysis of (D)-2-hydroxyglutarate.

Levels of (D)-2-hydroxyglutarate [D2HG, (R)-2-hydroxyglutarate] are increased in some metabolic diseases and in neoplasms with mutations in the isocitrate dehydrogenase 1 (IDH1) and isocitrate dehydrogenase 2 (IDH2) genes. Determination of D2HG is of relevance to diagnosis and monitoring of disease. Standard detection methods of D2HG levels are liquid-chromatography-mass spectrometry or gas-chromatography-mass spectrometry.

Chromogenic in situ hybridization is a reliable alternative to fluorescence in situ hybridization for diagnostic testing of 1p and 19q loss in paraffin-embedded gliomas.

Recent studies imply the importance of rapid and reliable diagnostic assessment of 1p/19q status in oligodendroglial tumors. To date, fluorescence in situ hybridization (FISH) is the most commonly applied technique. FISH, however, has several technical shortcomings that are suboptimal for diagnostic applications: results must be viewed in a fluorescence microscope, results are usually evaluated by a single investigator only, and signal fading excludes physical archiving.

Hotspot mutations in H3F3A and IDH1 define distinct epigenetic and biological subgroups of glioblastoma.

Glioblastoma (GBM) is a brain tumor that carries a dismal prognosis and displays considerable heterogeneity. We have recently identified recurrent H3F3A mutations affecting two critical amino acids (K27 and G34) of histone H3.3 in one-third of pediatric GBM.

Glutathione peroxidase 1 activity dictates the sensitivity of glioblastoma cells to oxidative stress.

The high intratumoral and intertumoral heterogeneity of glioblastoma (GBM) leads to resistance to different therapies, and hence, selecting an effective therapy is very challenging. We hypothesized that the antioxidant enzyme status is a significant feature of GBM heterogeneity. The most important reactive oxygen/nitrogen species (ROS/RNS) detoxification mechanisms include superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx).

Potential canonical wnt pathway activation in high-grade astrocytomas.

Aberrant wnt pathway activation through cytoplasmic stabilization of β-catenin is crucial for the development of various human malignancies. In gliomagenesis, the role of canonical (i.e.

Clonal analysis in recurrent astrocytic, oligoastrocytic and oligodendroglial tumors implicates IDH1- mutation as common tumor initiating event.

Background: To investigate the dynamics of inter- and intratumoral molecular alterations during tumor progression in recurrent gliomas.

Methodology/principal Findings: To address intertumoral heterogeneity we investigated non-microdissected tumor tissue of 106 gliomas representing 51 recurrent tumors. To address intratumoral heterogeneity a set of 16 gliomas representing 7 tumor pairs with at least one recurrence, and 4 single mixed gliomas were investigated by microdissection of distinct oligodendroglial and astrocytic tumor components.

Dissecting the genomic complexity underlying medulloblastoma.

Medulloblastoma is an aggressively growing tumour, arising in the cerebellum or medulla/brain stem. It is the most common malignant brain tumour in children, and shows tremendous biological and clinical heterogeneity. Despite recent treatment advances, approximately 40% of children experience tumour recurrence, and 30% will die from their disease.

LGR5 is a marker of poor prognosis in glioblastoma and is required for survival of brain cancer stem-like cells.

In various types of cancers including glioblastoma, accumulating evidence show the existence of cancer stem-like cells (CSCs), characterized by stem cell marker expression, capability of differentiation and self-renewal, and high potential for tumor propagation in vivo. LGR5, whose expression is positively regulated by the Wnt signaling pathway, is a stem cell marker in intestinal mucosa and hair follicle in the skin. As Wnt signaling is also involved in brain development, the function of LGR5 in the maintenance of brain CSCs is to be assessed.

CIC and FUBP1 mutations in oligodendrogliomas, oligoastrocytomas and astrocytomas.

CIC and FUBP1 mutations have recently been detected in oligodendrogliomas but not in oligoastrocytomas. However, allelic losses in the regions on chromosomal arms 19q and 1p harboring CIC and FUBP1 are a common feature of both, oligodendrogliomas and oligoastrocytomas. To resolve this discrepancy, we analyzed CIC and FUBP1 mutations in a set of primary brain tumors including 18 oligodendrogliomas and 42 oligoastrocytomas.