Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

The effect of HES6 silencing on the gene expression profiles of the glioblastoma A172 and LN405 cell lines

ABSTRACT: Malignant glioma is the most common type of primary brain tumor diagnosed annually in 16,000 individuals in the United States. We performed a systematic large-scale transcriptomics data mining study of 9,783 Affymetrix samples from the GeneSapiens database in order to identify those genes that are most glioma-specific as compared to other cancers and normal tissues. We searched for genes that are highly expressed in 322 glioblastoma multiforme tissue samples and 66 anaplastic astrocytomas as compared to 425 samples from histologically normal central nervous system. Transcription cofactor HES6 (Hairy and Enhancer of Split 6) emerged as one of the most glioma-specific genes. In immunostaining of a tissue microarray series, HES6 was expressed in 335 (98.8%) out of the 339 clinical glioma samples. Recurrent grade 2 astrocytomas and grade 2-3 oligodendrogliomas showed higher levels of HES6 immunoreactivity than the corresponding primary tumors. Functional studies implied a critical role for HES6 in supporting survival of glioma cells, as evidenced by 60% reduced cancer cell viability and induction of Caspase 3/7 activity after HES6 silencing by RNA interference in A172 and LN405 cells. The biological role and consequences of HES6 silencing and overexpression was explored with genome-wide analyses, which indicated a key role for HES6 in e.g. p53, c-myc, and NF-?B transcriptional networks. We conclude that HES6 has a critical role in sustaining glioma cell growth, survival, migration and possibly angiogenesis. HES6 is a potential therapeutic target and biomarker for glioma. A172 and LN405 cells (240 000 per well on 6-well plates) were transfected for 12-24 h with siHES6 pool, or three individual siRNAs (HES6_1, HES6_2, HES6_3 from Qiagen) or AllStars negative control siRNA (Qiagen) at 30 nM using SiLentFect (Bio-Rad Laboratories, Hercules, CA). One to two biological replicate transfections were performed. LN405 cells were also used for creating stable cell lines by transfecting either pEYFP-C1-mock or pEYFP-HES6 with Fugene6 (Roche) and selecting the positive cells with 600ug/ml of G418 (Sigma). The cells were kept in culture in the presence of 400ug/ml of G418. Total RNA was isolated with RNeasy (Qiagen) or MiRVana? Total RNA Isolation kit (Ambion). RNA quality was evaluated by using an Agilent 2100 Bioanalyzer (Agilent Technologies, Palo Alto, CA).

ORGANISM(S): Homo sapiens

SUBMITTER: Saija Haapa-Paananen

PROVIDER: E-GEOD-22692 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Similar Datasets

Project description:Glioblastoma multiforme (GBM) is the most aggressive form of brain tumors. Despite radical surgery and radiotherapy supported by chemotherapy, the disease still remains incurable with extremely low median survival rate of 12-15 months from the time of initial diagnosis. The main cause of treatment failure is considered to be the presence of cells that are resistant to such treatment. MicroRNAs (miRNAs) as regulators of gene expression are involved in the tumor pathogenesis, including GBM. MiR-338 is a brain specific miRNA which has been described to target pathways involved in proliferation and differentiation. In our study, miR-338-3p and -5p were differentially expressed in GBM tissue in comparison to non-tumor brain tissue. Overexpression of miR-338-3p with miRNA mimic did not show any changes in proliferation rates in GBM cell lines (A172, T98G, U87MG). On the other hand, pre-miR-338-5p notably decreased proliferation and caused cell cycle arrest. Since radiation is currently the main treatment modality in GBM, we combined overexpression of pre-miR-338-5p with radiation, which led to significantly decreased of cell proliferation, and increased cell cycle arrest and apoptosis in comparison to only irradiated cells. To better elucidate the mechanism of action, we performed gene expression profiling analysis that revealed targets of miR-338-5p being Ndfip1, Rheb, ppp2R5a. These genes have been described to be involved in DNA damage response, proliferation and cell cycle regulation. To our knowledge, this is the first study to describe role of miR-338-5p in GBM and its potential to improve sensitivity of GBM to radiation. Study was performed on three glioblastoma multiforme cell lines A172, T98G and U87MG. This experiment was performed on Affymetrix GeneChip Human Gene ST 1.0 to elucidate the targets of miRNA-338-5p. Cell lines were seeded 24 hours prior transfection. After transfection with pre-miR338-5p or negative control cell were cultured for 24 hours and harvested. RNA was isolated using MirVana miRNA Isolation Kit (Ambion, USA) and checked for RNA integrity by Bioanalyzer 2100 and purity by ratios 260/280>1.8 and 260/230>1.8 by Nanodrop2000.

Project description:Branching from conduits is a defining feature of the gas delivery systems of invertebrates (tracheae built from epithelial cells) and vertebrates (vasculature lined by endothelial cells). Here, we show that the vertebrate transcriptional repressor Tel plays an evolutionarily conserved role in angiogenesis: it is indispensable for sprouting of primary human endothelial cells and for the normal development of the Danio rerio embryo blood circulatory system. Tel controls endothelial sprouting via binding to the generic co-repressor C-terminal binding protein (CtBP). In endothelial cells, the Tel:CtBP complex temporally restricts a VEGF-mediated pulse of dll4 expression and consequently integrates VEGFR intracellular signaling and intercellular Notch-Dll4 signaling. It further refines branching by regulating expression of other factors that constrain angiogenesis such as sprouty family members and ve-cadherin. Thus, the Tel:CtBP complex moderates the balance between positive and antagonistic angiogenesis cues and thereby conditions endothelial cells for angiogenesis. Since the activity of CtBP is attuned to intracellular NADH levels, our results raise the possibility that Tel-mediated sprouting could be sensitized to the metabolic status of the tissue. Tel control of branching appears to be evolutionarily conserved since Yan, the invertebrate orthologue of Tel, is similarly required for branching morphogenesis of the invertebrate tracheae. Collectively, our work suggests that Tel is a central regulator of angiogenesis and highlights Tel and its associated networks as potential targets for the development of therapeutic strategies to inhibit pathological angiogenesis. 2 independent screens were performed testing effects of knockdown of Tel or CtBP (screen 1) or effects of VEGF-A (screen 2) on Human Umbilical Vein Endothelial Cells (HUVECs). For screen 1 we tested 3 different conditions. We established stable HUVEC cell lines which were either infected with control lentivirus (Mock), or lentivirus expressing short hairpin RNA constructs for the specific knockdown of Tel(Teli) or CtBP2 (CtBP2i). Expression in the Teli and CtBP2i cell lines was compared to expression in the Mock cell line for screen 1. For screen 2 we tested 2 conditions. We exposed HUVECs to VEGF (50ng/mL) for 30 minutes (samplename: VEGF30) and compared the transcriptome of these cells to untreated HUVECs (VEGF0). For each condition 2 independent repeats were analyzed and expression of genes was averaged for each repeat. HUVECs were grown under standard conditions (37degrees Celsius, 5% CO2) in EGM2 medium (Lonza).

Dataset Information

The effect of HES6 silencing on the gene expression profiles of the glioblastoma A172 and LN405 cell lines

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure