Stem cell-associated heterogeneity in Glioblastoma results from intrinsic tumor plasticity shaped by the microenvironment.

The identity and unique capacity of cancer stem cells (CSC) to drive tumor growth and resistance have been challenged in brain tumors. Here we report that cells expressing CSC-associated cell membrane markers in Glioblastoma (GBM) do not represent a clonal entity defined by distinct functional properties and transcriptomic profiles, but rather a plastic state that most cancer cells can adopt. We show that phenotypic heterogeneity arises from non-hierarchical, reversible state transitions, instructed by the microenvironment and is predictable by mathematical modeling.

Maintenance therapy with histamine plus IL-2 induces a striking expansion of two CD56bright NK cell subpopulations in patients with acute myeloid leukemia and supports their activation.

Histamine dihydrochloride (HDC) plus IL-2 has been proposed as a novel maintenance-immunotherapy in acute myeloid leukemia (AML). We analyzed the immunophenotype and function of natural killer (NK) cells in blood of AML patients treated after chemotherapy with HDC plus IL-2. The treatment caused a striking expansion of CD56brightCD16neg and CD56brightCD16low NK cell subpopulations.

Molecular crosstalk between tumour and brain parenchyma instructs histopathological features in glioblastoma.

The histopathological and molecular heterogeneity of glioblastomas represents a major obstacle for effective therapies. Glioblastomas do not develop autonomously, but evolve in a unique environment that adapts to the growing tumour mass and contributes to the malignancy of these neoplasms. Here, we show that patient-derived glioblastoma xenografts generated in the mouse brain from organotypic spheroids reproducibly give rise to three different histological phenotypes: (i) a highly invasive phenotype with an apparent normal brain vasculature, (ii) a highly angiogenic phenotype displaying microvascular proliferation and necrosis and (iii) an intermediate phenotype combining features of invasion and vessel abnormalities.

NK cell killer Ig-like receptor repertoire acquisition and maturation are strongly modulated by HLA class I molecules.

The interaction between clonally distributed inhibitory receptors and their activating counterparts on NK cells and HLA class I molecules defines NK cell functions, but the role of HLA class I ligands in the acquisition of their receptors during NK development is still unclear. Although some studies demonstrated that HLA-C affects the expression of killer Ig-like receptors (KIR), other studies showed that NK cells acquire their KIR repertoire in a stochastic manner. Only when infected with human CMV is an expansion of self-specific KIR(+) NKG2C(+) NK cells detected.

Glioblastomas are composed of genetically divergent clones with distinct tumourigenic potential and variable stem cell-associated phenotypes.

Glioblastoma (GBM) is known to be a heterogeneous disease; however, the genetic composition of the cells within a given tumour is only poorly explored. In the advent of personalised medicine the understanding of intra-tumoural heterogeneity at the cellular and the genetic level is mandatory to improve treatment and clinical outcome. By combining ploidy-based flow sorting with array-comparative genomic hybridization we show that primary GBMs present as either mono- or polygenomic tumours (64 versus 36%, respectively).

Elevated CD3+ and CD8+ tumor-infiltrating immune cells correlate with prolonged survival in glioblastoma patients despite integrated immunosuppressive mechanisms in the tumor microenvironment and at the systemic level.

We characterized GBM patients' tumor and systemic immune contexture with aim to reveal the mechanisms of immunological escape, their impact on patient outcome, and identify targets for immunotherapy. Increased CD3(+) T-cell infiltration was associated with prolonged survival independent of age, MGMT promoter methylation and post-operative treatment that implies potential for immunotherapy for GBM. Several mechanisms of escape were identified: within the tumor microenvironment: induced CD8(+)CD28(-)Foxp3(+) Tregs that may tolerize antigen presenting cells, elevated CD73 and CD39 ectonucleotidases that suppress T-cell function, and at the systemic level: elevated IL-10 levels in serum, diminished helper T-cell counts, and upregulated inhibitory CTLA-4.

Side population in human glioblastoma is non-tumorigenic and characterizes brain endothelial cells.

The identification and significance of cancer stem-like cells in malignant gliomas remains controversial. It has been proposed that cancer stem-like cells display increased drug resistance, through the expression of ATP-binding cassette transporters that detoxify cells by effluxing exogenous compounds. Here, we investigated the 'side population' phenotype based on efflux properties of ATP-binding cassette transporters in freshly isolated human glioblastoma samples and intracranial xenografts derived thereof.

Mouse lung and spleen natural killer cells have phenotypic and functional differences, in part influenced by macrophages.

NK cells are lymphocytes of the innate immune system which are a first line of defense against infections and tumor cells, in bone marrow and peripheral organs like lung and spleen. The lung is an organ in contact with respiratory pathogens and the site of inflammatory disorders triggered by the respiratory environment. In contrast, spleen is a lymphatic organ connected to the blood system which regulates the systemic immune response.

Expression of the progenitor marker NG2/CSPG4 predicts poor survival and resistance to ionising radiation in glioblastoma.

Glioblastoma (GBM) is a highly aggressive brain tumour, where patients respond poorly to radiotherapy and exhibit dismal survival outcomes. The mechanisms of radioresistance are not completely understood. However, cancer cells with an immature stem-like phenotype are hypothesised to play a role in radioresistance.

Increased Th2 cytokine secretion, eosinophilic airway inflammation, and airway hyperresponsiveness in neurturin-deficient mice.

Neurotrophins such as nerve growth factor and brain-derived neurotrophic factor have been described to be involved in the pathogenesis of asthma. Neurturin (NTN), another neurotrophin from the glial cell line-derived neurotrophic factor family, was shown to be produced by human immune cells: monocytes, B cells, and T cells. Furthermore, it was previously described that the secretion of inflammatory cytokines was dramatically stimulated in NTN knockout (NTN(-/-)) mice.

Critical appraisal of the side population assay in stem cell and cancer stem cell research.

The "Side Population" (SP) discrimination assay is a flow cytometry method used to detect stem cells based on the dye efflux properties of ABC transporters. We discuss the SP assay and its applications in stem cell biology, with an emphasis on the technical challenges related to sample preparation, data acquisition, analysis, and interpretation. We highlight the value of multicolor phenotyping, the impact of DNA ploidy, and the importance of distinguishing graft versus host cells for an appropriate SP discrimination.

Mouse natural killer (NK) cells express the nerve growth factor receptor TrkA, which is dynamically regulated.

Background: Nerve growth factor (NGF) is a neurotrophin crucial for the development and survival of neurons. It also acts on cells of the immune system which express the NGF receptors TrkA and p75(NTR) and can be produced by them. However, mouse NK cells have not yet been studied in this context.

Novel method for isolating untouched rat natural killer cells with higher purity compared with positive selection and fluorescence-activated cell sorting.

Natural killer (NK) cells are important effectors of both innate and adaptive immune responses. Although human and mouse NK cells are extensively characterized, much less is known about the rat cells, partly because of the current lack of reliable isolation techniques. We aimed to develop a method for isolating highly pure 'untouched' rat NK cells by negative selection from splenocytes.

The histone deacetylase inhibitor MGCD0103 induces apoptosis in B-cell chronic lymphocytic leukemia cells through a mitochondria-mediated caspase activation cascade.

Clinical trials have shown activity of the isotype-selective histone deacetylase (HDAC) inhibitor MGCD0103 in different hematologic malignancies. There are data to support the use of HDAC inhibitors in association with other cancer therapies. To propose a rational combination therapy, it is necessary to depict the molecular basis behind the cytotoxic effect of MGCD0103.

Anti-cancer effects of 20(S)-protopanoxadiol on human acute lymphoblastic leukemia cell lines Reh and RS4;11.

Although the treatment outcome of acute lymphoblastic leukemia (ALL) has been improved in the past decades by combination chemotherapy, toxic side-effects of chemotherapeutics remain a major problem. Therefore, new alternative agents with low toxicity are urgently needed. Natural products provide a rich source of screening potential anti-cancer drugs.

Peroxisome proliferator-activated receptor gamma agonists potentiate the cytotoxic effect of valproic acid in multiple myeloma cells.

The main challenge in using chemotherapy to treat multiple myeloma (MM) is drug resistance. In order to evaluate the anti-neoplastic properties of a new drug combination in MM, two clinically available drugs, valproic acid (VPA) a histone deacetylase (HDAC) inhibitor and pioglitazone, a peroxisome proliferator-activated receptor gamma (PPARgamma) agonist, were tested in vitro on MM cell lines and MM patient cells. The sensitivity towards VPA alone was observed on several MM cell lines tested and also on primary myeloma cells and peripheral blood mononuclear cells from healthy donors.

A novel eGFP-expressing immunodeficient mouse model to study tumor-host interactions.

A NOD/Scid mouse expressing enhanced green fluorescent protein (eGFP) is described, in which human and mouse tumors marked with red fluorescent protein can be established in vivo, both at subcutaneous and orthotopic locations. Using light microscopy as well as multiphoton confocal microscopy techniques, we visualized in detail the intricate colocalization of tumor and host cells in situ. Moreover, using fluorescence-activated cell sorting (FACS), we were able to completely separate the host cells from the tumor cells, thus providing a system for detailed cellular and molecular analysis of tumor-host cell interactions.

Reduced cytokine-mediated up-regulation of HLA-DR in TAP-deficient fibroblasts.

Human deficiency in transporter associated with antigen processing (TAP) is characterized by a very low surface expression of human leukocyte antigen (HLA) class I molecules in hematopoietic and non hematopoietic cells. Among the latter, TAP-deficient skin fibroblasts have previously been shown by us to be very sensitive to lysis by activated autologous NK cells, even in the presence of cytokines that up-regulate HLA class I expression, a mechanism sufficient to protect normal fibroblasts from NK cell-mediated killing. Our complementary investigations on two TAP-deficient skin fibroblast cell lines surprisingly revealed that in response to proinflammatory cytokines, up-regulation of HLA-DR molecules at the cell surface is much less marked than in the case of normal skin fibroblasts.

HPA-1a phenotype-genotype discrepancy reveals a naturally occurring Arg93Gln substitution in the platelet beta 3 integrin that disrupts the HPA-1a epitope.

A single nucleotide polymorphism (SNP) at position 196 in the beta 3 integrin causes a Leu33Pro substitution in the mature protein. Alloimmunization against the beta 3Leu33 form (human platelet antigen [HPA]-1a, Pl(A1), Zw(a)) in patients who are beta 3Pro33 homozygous (HPA-1b1b, Pl(A2A2), Zw(bb)) causes neonatal alloimmune thrombocytopenia, posttransfusion purpura, or refractoriness to platelet transfusion. Studies with recombinant proteins have demonstrated that amino acids 1 to 66 and 288 to 490 of the beta 3 integrin contribute to HPA-1a epitope formation.