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Functional profiling of precursor MicroRNAs identifies MicroRNAs essential for glioma proliferation.

ABSTRACT: Cancer initiation and progression involve microRNAs that can function like tumor suppressors and oncogenes. The functional significance of most miRNAs is currently unknown. To determine systematically which microRNAs are essential for glioma growth, we screened a precursor microRNA library in three human glioblastoma and one astroglial cell line model systems. The most prominent and consistent cell proliferation-reducing hits were validated in secondary screening with an additional apoptosis endpoint. The functional screening data were integrated in the miRNA expression data to find underexpressed true functional tumor suppressor miRNAs. In addition, we used miRNA-target gene predictions and combined siRNA functional screening data to find the most probable miRNA-target gene pairs with a similar functional effect on proliferation. Nine novel functional miRNAs (hsa-miR-129, -136, -145, -155, -181b, -342-5p, -342-3p, -376a/b) in GBM cell lines were validated for their importance in glioma cell growth, and similar effects for six target genes (ROCK1, RHOA, MET, CSF1R, EIF2AK1, FGF7) of these miRNAs were shown functionally. The clinical significance of the functional hits was validated in miRNA expression data from the TCGA glioblastoma multiforme (GBM) tumor cohort. Five tumor suppressor miRNAs (hsa-miR-136, -145, -342, -129, -376a) showed significant underexpression in clinical GBM tumor samples from the TCGA GBM cohort further supporting the role of these miRNAs in vivo. Most importantly, higher hsa-miR-145 expression in GBM tumors yielded significantly better survival (p<0.005) in a subset of patients thus validating it as a genuine tumor suppressor miRNA. This systematic functional profiling provides important new knowledge about functionally relevant miRNAs in GBM biology and may offer new targets for treating glioma.

SUBMITTER: Haapa-Paananen S

PROVIDER: S-EPMC3618426 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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Functional profiling of precursor MicroRNAs identifies MicroRNAs essential for glioma proliferation.

Haapa-Paananen Saija S Chen Ping P Hellström Kirsi K Kohonen Pekka P Hautaniemi Sampsa S Kallioniemi Olli O Perälä Merja M

PloS one 20130405 4

Cancer initiation and progression involve microRNAs that can function like tumor suppressors and oncogenes. The functional significance of most miRNAs is currently unknown. To determine systematically which microRNAs are essential for glioma growth, we screened a precursor microRNA library in three human glioblastoma and one astroglial cell line model systems. The most prominent and consistent cell proliferation-reducing hits were validated in secondary screening with an additional apoptosis end ...[more]

PMID: 23577178

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Project description:BACKGROUND: Molecular mechanisms explaining age-related changes in the bone marrow with reduced precursor B cell output are poorly understood. METHODS: We studied the transcriptome of five precursor B cell subsets in individual bone marrow samples from 4 healthy children and 4 adults employing GeneChip® Human Exon 1.0 ST Arrays (Affymetrix®) and TaqMan® Array MicroRNA Cards (Life Technologies™). RESULTS: A total of 1796 mRNAs (11%) were at least once differentially expressed between the various precursor B cell subsets in either age group (FDR 0.1%, p?1.13×10(-4)) with more marked cell stage specific differences than those related to age. In contrast, microRNA profiles of the various precursor B cell subsets showed less hierarchical clustering as compared to the corresponding mRNA profiles. However, 17 of the 667 microRNA assays (2.5%) were at least once differentially expressed between the subsets (FDR 10%, p?0.004). From target analysis (Ingenuity® Systems), functional assignment between postulated interacting mRNAs and microRNAs showed especially association to cellular growth, proliferation and cell cycle regulation. One functional network connected up-regulation of the differentiation inhibitor ID2 mRNA to down-regulation of the hematopoiesis- or cell cycle regulating miR-125b-5p, miR-181a-5p, miR-196a-5p, miR-24-3p and miR-320d in adult PreBII large cells. Noteworthy was also the stage-dependent expression of the growth promoting miR-17-92 cluster, showing a partly inverse trend with age, reaching statistical significance at the PreBII small stage (up 3.1-12.9 fold in children, p?=?0.0084-0.0270). CONCLUSIONS: The global mRNA profile is characteristic for each precursor B cell developmental stage and largely similar in children and adults. The microRNA profile is much cell stage specific and not changing much with age. Importantly, however, specific age-dependent differences involving key networks like differentiation and cellular growth may indicate biological divergence and possibly also altered production potential with age.

Project description:An integrative functional genomics of multiple forms of data is vital for discovering molecular drivers of cancer development and progression. Here, we present an integrated genomic strategy utilizing DNA methylation and transcriptome profile data to discover epigenetically regulated genes implicated in cancer development and invasive progression. More specifically, this analysis identified Fibromodulin (FMOD) as a glioblastoma (GBM) upregulated gene due to the loss of promoter methylation. Secreted FMOD promotes glioma cell migration through its ability to induce filamentous actin stress fiber formation. Treatment with Cytochalasin D, an actin polymerization inhibitor, significantly reduced the FMOD induced glioma cell migration. siRNA and small molecule inhibitor-based studies identified that FMOD-induced glioma cell migration is dependent on Integrin-FAK-Src-Rho-ROCK signaling pathway. FMOD lacking C terminus LRR11 domain (FMOD), which does not bind collagen type I, failed to induce integrin and promote glioma cell migration. Further, FMOD-induced integrin activation and migration was abrogated by a 9-mer wild type peptide from the FMOD C-terminus. However, the same peptide with mutation in two residues essential for FMOD interaction with collagen type I failed to compete with FMOD, thus signifying the importance of collagen type I-FMOD interaction in integrin activation. ChIP-PCR experiments revealed that TGF-Ã1 regulates FMOD expression through epigenetic remodeling of FMOD promoter that involved demethylation and gain of active histone marks with a simultaneous loss of DNMT3A and EZH2 occupancy, but enrichment of SMAD2 and CBP. FMOD silencing inhibited the TGF-Ã1 mediated glioma cell migration significantly. In univariate and multivariate cox regression analysis, both FMOD promoter methylation and transcript levels predicted prognosis in GBM. Thus, the present study identified several epigenetically regulated alterations responsible for cancer development and progression. Specifically, we found that secreted FMOD as an important regulator of glioma cell migration downstream of TGF-Ã1 pathway and forms a potential basis for therapeutic intervention in GBM. We used DNA isolated from 17 diffuse astrocytoma, 16 anaplastic astrocytoma, 36 glioblastoma and 9 control brain tissue for the array. P53 status: All cases were subjected to histopathology and the diagnosis of GBM was confirmed. Paraffin sections (4 Î¼m) from the tissues were collected on silane-coated slides, and the protein expression of p53 was assessed by immunohistochemistry (IHC). Antigen retrieval was done by heat treatment at 850W in citrate buffer or at 700W. After the initial processing steps, sections were incubated overnight with primary antibody for p53 (Mouse Monoclonal DO-7; Biogenex, USA)at 4Â°C with 1: 200 dilution. MIB: Paraffin blocks of all the cases were retrieved, and histological features were reviewed on freshly cut and stained (hematoxylin and eosin) sections. After confirming the diagnosis of glioblastoma, 4 Âµm thick sections were collected on silane-coated slides, and IHC was performed using MIB-1 (anti Ki-67 monoclonal BGX 297, diluted to 1:30) EGFR status: Paraffin blocks of all the cases were retrieved, and histological features were reviewed on freshly cut and stained (hematoxylin and eosin) sections. After confirming the diagnosis of glioblastoma, 4 Âµm thick sections were collected on silane-coated slides, and IHC was performed using EGFR (monoclonal E-30, diluted to 1:50) GFAP status: Paraffin blocks of all the cases were retrieved, and histological features were reviewed on freshly cut and stained (hematoxylin and eosin) sections. After confirming the diagnosis of glioblastoma, 4 Âµm thick sections were collected on silane-coated slides, and IHC was performed using glial fibrillary acidic protein (GFAP, monoclonal GA-5, diluted to 1:100).

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Functional profiling of precursor MicroRNAs identifies MicroRNAs essential for glioma proliferation.

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Functional profiling of precursor MicroRNAs identifies MicroRNAs essential for glioma proliferation.

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