DACH1 expression in U87 cells
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ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Watanabe Akira
PROVIDER: S-ECPF-GEOD-19678 | biostudies-other |
REPOSITORIES: biostudies-other
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Project description:How cancer cells adapt to hypoxia during tumor development remains an important question. The hypothesis tested in the present study was that tumor cell-derived exosome vesicles (also known as microvesicles or extracellular vesicles) are mediators of hypoxia-dependent intercellular signaling in glioblastoma (GBM), i.e. highly aggressive brain tumors characterized by hypoxia and a vascular density that is among the highest of all human malignancies. In vitro hypoxia experiments and studies with patient materials reveal the enrichment in exosomes of hypoxia-regulated mRNAs and proteins, several of which were associated with poor patient prognosis. We show that cancer cell exosomes mediate hypoxia-dependent, phenotypic modulation of stromal cells in vitro and ex vivo, resulting in accelerated GBM tumor angiogenesis and growth in mice. These data suggest that exosomes constitute potent mediators of hypoxia-driven tumor development, and circulating multiparameter biomarkers of tumor hypoxia. U87 MG glioblastoma cells were grown at normoxic (21% oxygen) or hypoxic (1% oxygen) conditions for 48 hours. Conditioned media from normoxic and hypoxic cells were then used to isolate exosomes by differential centrifugation. Both cells and exosomes were lysed in Trizol reagent, and RNA was isolated.Total RNA from all samples (four types of samples in three biological repilicates) was subjected to genome-wide transcriptional analysis with Illumina HumanHT-12 V3.0 expression beadchip. Gene expression profile obtained from hypoxic U87 MG glioblastoma cells was compared to the profile of normoxic control cells. Analogically, gene expression profile obtained from hypoxic U87 MG cells was compared to the profile of exosomes secreted by normoxic U87 MG cells.
| S-ECPF-GEOD-45301 | biostudies-other
Project description:Epidermal growth factor (EGF) receptors contribute to the development of malignant glioma. Here we considered the possible implication of the EGFR ligand epiregulin (EREG) in glioma development in relation to the activity of the unfolded protein response (UPR) sensor IRE1?. We also examined EREG status in several glioblastoma cell lines and in malignant glioma.Expression and biological properties of EREG were analyzed in human glioma cells in vitro and in human tumor xenografts with regard to the presence of ErbB proteins and to the blockade of IRE1?. Inactivation of IRE1? was achieved by using either the dominant-negative strategy or siRNA-mediated knockdown.EREG was secreted in high amounts by U87 cells, which also expressed its cognate EGF receptor (ErbB1). A stimulatory autocrine loop mediated by EREG was evidenced by the decrease in cell proliferation using specific blocking antibodies directed against either ErbB1 (cetuximab) or EREG itself. In comparison, anti-ErbB2 antibodies (trastuzumab) had no significant effect. Inhibition of IRE1? dramatically reduced EREG expression both in cell culture and in human xenograft tumor models. The high-expression rate of EREG in U87 cells was therefore linked to IRE1?, although being modestly affected by chemical inducers of the endoplasmic reticulum stress. In addition, IRE1-mediated production of EREG did not depend on IRE1 RNase domain, as neither the selective dominant-negative invalidation of the RNase activity (IRE1 kinase active) nor the siRNA-mediated knockdown of XBP1 had significant effect on EREG expression. Finally, chemical inhibition of c-Jun N-terminal kinases (JNK) using the SP600125 compound reduced the ability of cells to express EREG, demonstrating a link between the growth factor production and JNK activation under the dependence of IRE1?.EREG may contribute to glioma progression under the control of IRE1?, as exemplified here by the autocrine proliferation loop mediated in U87 cells by the growth factor through ErbB1.
| S-EPMC3878670 | biostudies-literature
Project description:A novel suicide gene therapy approach was tested in U87 MG glioblastoma multiforme cells. A 26nt G-rich double-stranded DNA aptamer (AS1411) was integrated into a vector at the 5' of a mammalian codon-optimized saporin gene, under CMV promoter. With this plasmid termed "APTSAP", the gene encoding ribosome-inactivating protein saporin is driven intracellularly by the glioma-specific aptamer that binds to cell surface-exposed nucleolin and efficiently kills target cells, more effectively as a polyethyleneimine (PEI)-polyplex. Cells that do not expose nucleolin at the cell surface such as 3T3 cells, used as a control, remain unaffected. Suicide gene-induced cell killing was not observed when the inactive saporin mutant SAPKQ DNA was used in the (PEI)-polyplex, indicating that saporin catalytic activity mediates the cytotoxic effect. Rather than apoptosis, cell death has features resembling autophagic or methuosis-like mechanisms. These main findings support the proof-of-concept of using PEI-polyplexed APTSAP for local delivery in rat glioblastoma models.
| S-EPMC8082512 | biostudies-literature
Project description:BackgroundGlioma cells not only secrete high levels of vascular endothelial growth factor (VEGF) but also express VEGF receptors (VEGFR), supporting the existence of an autocrine loop. The direct impact on glioma cells metabolism of drugs targeting the VEGF pathway, such as Bevacizumab (Bev) or VEGFR Tyrosine Kinase Inhibitor (TKI), is poorly known.Material and methodsU87 cells were treated with Bev or SU1498, a selective VEGFR2 TKI. VEGFR expression was checked with FACS flow cytometry and Quantitative Real-Time PCR. VEGF secretion into the medium was assessed with an ELISA kit. Metabolomic studies on cells were performed using High Resolution Magic Angle Spinning Spectroscopy (HR-MAS).ResultsU87 cells secreted VEGF and expressed low level of VEGFR2, but no detectable VEGFR1. Exposure to SU1498, but not Bev, significantly impacted cell proliferation and apoptosis. Metabolomic studies with HR MAS showed that Bev had no significant effect on cell metabolism, while SU1498 induced a marked increase in lipids and a decrease in glycerophosphocholine. Accordingly, accumulation of lipid droplets was seen in the cytoplasm of SU1498-treated U87 cells.ConclusionAlthough both drugs target the VEGF pathway, only SU1498 showed a clear impact on cell proliferation, cell morphology and metabolism. Bevacizumab is thus less likely to modify glioma cells phenotype due to a direct therapeutic pressure on the VEGF autocrine loop. In patients treated with VEGFR TKI, monitoring lipids with magnetic resonance spectroscopic (MRS) might be a valuable marker to assess drug cytotoxicity.
| S-EPMC4055646 | biostudies-literature
Project description:An experimental lung metastasis assay was used to derive an invasive subline of U87 that is metastatic in mice. We used microarray analyses to find out over-represented gene ontologies that can explain the observed enhanced invasiveness of U87-2M1 cells.
2012-12-31 | GSE35169 | GEO
Project description:Overall study: Identification of PDGF-dependent patterns of gene expression in U87 glioblastoma cells. RNA was obtained from triplicate dishes of 5 different groups of U87 cells, each (total 15) analyzed with one U95 microarray chip.,Three different comparisons were made:,1) Clone 3.1 (34580-34582) vs. clone 3.3 (34583-34585) vs. parent U87 (34592-34594).,Purpose: demonstrate that the gene expression profiles between these 3 cell lines are not different, so they could be pooled as a single untreated group.,2) Pooled control group (34580-34585, 34592-34594) vs. clone 8.1 (34586-34588).,Purpose: identify genes specifically controlled by autocrine PDGF activity.,3) Clone 8.1 (34586-34588),vs. clone 8.1 treated with PDGF (34589-34591),Purpose: Identify genes specifically induced by exogenous PDGF.
| S-ECPF-GEOD-1923 | biostudies-other
Project description:An experimental lung metastasis assay was used to derive an invasive subline of U87 that is metastatic in mice. We used microarray analyses to find out over-represented gene ontologies that can explain the observed enhanced invasiveness of U87-2M1 cells. Early passage U87-2M1 cells and parental U87 glioma cells from ATCC were selected for RNA extraction and hybridization on microarray
2012-12-31 | E-GEOD-35169 | biostudies-arrayexpress
Project description:Loss or reduction in function of tumor suppressor genes contributes to tumorigenesis. We identified a novel homozygous deletion of DACH1 in gliomas. We generated U87TR-Da glioma cell line, where DACH1 expression could be activated by exposure of cells to doxycycline, and examined changing global gene expression by DACH1 expression.
2011-07-20 | GSE19678 | GEO
Project description:BackgroundThe CD133(+) stem cell population in recurrent gliomas is associated with clinical features such as therapy resistance, blood-brain barrier disruption and, hence, tumor infiltration. Screening of a large panel of glioma samples increasing histological grade demonstrated frequencies of CD133(+) cells which correlated with high expression of cyclooxygenase (COX)-2 and of membrane type-1 matrix metalloproteinase (MT1-MMP).MethodsWe used qRT-PCR and immunoblotting to examine the molecular interplay between MT1-MMP and COX-2 gene and protein expression in parental, CD133(+), and neurospheres U87 glioma cell cultures.ResultsWe found that CD133, COX-2 and MT1-MMP expression were enhanced when glioma cells were cultured in neurosphere conditions. A CD133(+)-enriched U87 glioma cell population, isolated from parental U87 cells with magnetic cell sorting technology, also grew as neurospheres and showed enhanced COX-2 expression. MT1-MMP gene silencing antagonized COX-2 expression in neurospheres, while overexpression of recombinant MT1-MMP directly triggered COX-2 expression in U87 cells independent from MT1-MMP's catalytic function. COX-2 induction by MT1-MMP was also validated in wild-type and in NF-kappaB p65-/- mutant mouse embryonic fibroblasts, but was abrogated in NF-kappaB 1 (p50-/-) mutant cells.ConclusionWe provide evidence for enhanced COX-2 expression in CD133(+) glioma cells, and direct cell-based evidence of NF-kappaB-mediated COX-2 regulation by MT1-MMP. The biological significance of such checkpoint control may account for COX-2-dependent mechanisms of inflammatory balance responsible of therapy resistance phenotype of cancer stem cells.
| S-EPMC2655289 | biostudies-literature
Project description:Analysis of expression changes of cultured HepG2 hepatoma, U87 glioma, and MDA-MB231 breast cancer cells subjected to hypoxia (0.5% O2) for 0, 4, 8, 12 hours . Results provide insight to cell type-specific response to hypoxia. HepG2 hepatoma, U87 glioma, and MDA-MB231 breast cancer cells were collected under normoxic conditions (~19% O2, 0 hours) and after 4, 8 and 12 hours of hypoxia treatment (0.5% O2). For each cell line, three replicates of total RNA at each time point were prepared using Trizol and submitted to the DFCI Microarray Core for labeling, hybridization to Affymetrix HG-U133Plus2 oligonucleotide arrays and image scanning.
| S-ECPF-GEOD-18494 | biostudies-other