Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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Analysis of microRNA expression profile in malignant glioma tissues

ABSTRACT: Malignant gliomas represent the most devastating group of brain tumors in adults, among which glioblastoma multiforme (GBM) exhibits the highest malignancy rate. Despite combined modality treatment, GBM recurs and is invariably fatal. A further insight into molecular background of gliomagenesis is required to improve patient outcome. The first aim of this study was to gain broad information on miRNA expression pattern in malignant gliomas, mainly GBM. We investigated the global miRNA profile of malignant glioma tissues by means of miRNA microarrays, deep sequencing and meta-analysis. We selected miRNAs the most frequently deregulated in glioblastoma tissues as well as peritumoral brain areas in comparison to normal human brain. We found candidate miRNAs contributing to progression from gliomas grade III to gliomas grade IV. The meta-analysis of miRNA profiling studies in GBM tissues summarizes the past and recent advances in an investigation of miRNA signature in GBM versus noncancerous human brain and provides a comprehensive overview. We proposed a set of 35 miRNAs which expression is the most frequently deregulated in GBM patients and 30 miRNA candidates recognized as novel GBM biomarkers. miRNA expression profile in the adult malignant gliomas, glioma peritumoral tissues and normal human brain.

ORGANISM(S): Homo sapiens

SUBMITTER: Magdalena M-EM-^AM-CM-3j

PROVIDER: E-GEOD-61710 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:In this study, we explored the transcriptomic consequences of strong activation of the Notch pathway in embryonic human neural stem cells and in gliomas. For this we used a forced expression of the Notch intracellular domain (NICD). Glioblastoma multiforms (GBMs) are highly vascularized brain tumors containing a subpopulation of multipotent cancer stem cells. These cells closely interact with endothelial cells in neurovascular niches. In this study we have uncovered a close link between the Notch1 pathway and the tumoral vascularization process of GBM stem cells. We observed that although the Notch1 receptor was activated, the typical target proteins (HES5, HEY1, HEY2) were not or barely expressed in two explored GBM stem cell cultures. Notch1 signalling activation by expression of the intracellular form (NICD) in these cells was found to reduce their growth rate and migration which was accompanied by the sharp reduction of neural stem cell transcription factor expression (ASCL1, OLIG2, SOX2) while HEY1/2, KLF9, SNAI2 transcription factors were upregulated. Expression of OLIG2 and growth were restored after termination of Notch1 stimulation. Remarkably, NICD expression induced the expression of pericyte cell markers (NG2, PDGFRb and a-smooth muscle actin (aSMA)) in GBM stem cells. This was paralleled with the induction of several angiogenesis-related factors most notably cytokines (HB-EGF, IL8, PLGF), metalloprotease (MMP9) and adhesion proteins (VCAM-1, ICAM-1, ITGA9). In xenotransplantation experiments, contrasting with the infiltrative and poorly-vascularized tumors obtained with control GBM stem cells, Notch1 stimulation resulted in poorly-disseminating but highly-vascularized grafts containing large vessels with lumen. Notch1-stimulated GBM cells expressed pericyte cell markers and closely associated with endothelial cells. These results reveal an important role for the Notch1 pathway in regulating GBM stem cell plasticity and angiogenic properties. Embryonic human neural progenitors obtained from Lonza, the U87 glioma cell line, and glioma cancer stem cells (Gb4 and Gb7) characterized in Guichet et al. (Glia, 2013, 61(2), 225-39) were infected with lentiviruses expressing YFP or YFP-IRES-NICD (activated form of Notch receptor). After 48h, RNA were extracted for Affymetrix microarray analysis.

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Analysis of microRNA expression profile in malignant glioma tissues

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