Project description:We showed that DBTRG is more invasive than U251 cell lines by novel brain-stiffness-mimicking matrix gel invasion platform and transwell invasion assay. To understand the molecular mechanisms of DBTRG being more invasive than U251, we performed transcriptomic sequencing analysis of DBTRG and U251 cell lines.
Project description:Gene expression profiling of SNB19 and U251 glioblastoma cell lines transfected with the FGFR3-TACC3 fusion, FGFR3 wildtype and TACC3 wildtype constructs.
Project description:Gene expression profiling of SNB19 and U251 glioblastoma cell lines transfected with the FGFR3-TACC3 fusion, FGFR3 wildtype and TACC3 wildtype constructs. SNB19 and U251 cells were transfected with different clones of the FGFR3-TACC3 fusion and with wildtype FGFR3 and TACC3 constructs. Total RNA was extracted and hybridized onto Agilent dual channel gene expression microarrays. In each hybridization, empty vector transfected SNB19 or U251 cells were hybridized into the reference channel.
Project description:Assess gene expression patterns upon HOXA9 ectopic expression in U87MG GBM cell line and hTERT/E6/E7 immortalized human astrocytes, and HOXA9 silencing in U251 and GBML18 GBM cell lines. U87MG and hTERT/E6/E7 were retrovirally-infected with an MSCV control vector (MSCV-Control) or with a construct containing the coding region of HOXA9 (MSCV-HOXA9), resulting in U87MG-Control, U87MG-HOXA9, hTERT/E6/E7-Control and hTERT/E6/E7-HOXA9 cell lines. GBML18 and U251 cells were transfected with HOXA9 gene-specific shRNA sequences (shHOXA9) or a non-efective shRNA (shControl) in pGFP-V-RS plasmid, resulting in U251-shControl, U251-shHOXA9, GBML18-shControl and GBML18-shHOXA9 cell lines. Four experimental replicates for HOXA9 overexpression cell lines, and three for HOXA9 silencing cell lines were performed.
Project description:Missense point mutations in the TP53 gene are frequent genetic alterations in human tumor tissue and cell lines derived thereof. Mutant p53 (mutp53) proteins have lost sequence-specific DNA binding, but have retained the ability to interact in a structure-selective manner with non-B DNA and to act as regulators of transcription. To identify functional binding sites of mutp53, we established a small library of genomic sequences bound by p53R273H in U251 human glioblastoma cells using chromatin immunoprecipitation (ChIP). Mutp53 binding to isolated DNA fragments confirmed the specificity of the ChIP. The mutp53 bound DNA sequences are rich in repetitive DNA elements, which are dispersed over non-coding DNA regions. Stable down-regulation of mutp53 expression strongly suggested that mutp53 binding to genomic DNA is functional. We identified the PPARGC1A and FRMD5 genes as p53R273H targets regulated by binding to intronic and intra-genic sequences. We propose a model that attributes the oncogenic functions of mutp53 to its ability to interact with intronic and intergenic non-B DNA sequences and modulate gene transcription via re-organization of chromatin. For the study of the consequences of mutant p53 (R273H) knockdown on gene expression, total RNA from parental U251 glioblastoma cells and UsiA12 clone was prepared from two independent cell culture experiments (biological replicates) and processed for microarray-based profiling of gene expression. UsiA12 clone was derived from the U251 cells transfected with the pSuper-p53 and pCI-neo vectors.
Project description:Assess gene expression patterns upon HOXA9 ectopic expression in U87MG GBM cell line and hTERT/E6/E7 immortalized human astrocytes, and HOXA9 silencing in U251 and GBML18 GBM cell lines.
Project description:we report that U251 glioblastoma tumor spheres exhibit low cytosolic folate cycle and a reprogrammmed mitochondrial folate cycle that is presumably oriented towards oxidizing the formyl group to CO2 with the production of TetraHydroFolate and release of NADPH instead of synthesizing formate
Project description:Missense mutations in the TP53 gene are frequent genetic alterations in human tumor tissue and cell lines. In contrast to wild-type p53, the mutant p53 (mutp53) protein has lost the transcriptional activity towards pro-apoptotic and growth arrest genes, but retained the property to interact with DNA in a structure-specific fashion. Expression of mutp53 is advantageous for tumor cells, however the molecular mechanism of mutp53 action is still not known. We used the glioblastoma-derived U-251 MG human cell line to analyze DNA binding of mutant p53 (R273H mutation) on a Nimblegen custom 135k tiling array and to correlate mutp53 binding regions with the epigenetic state and occupation by other transcription factors (ETS1 and SP1). We found that mutp53-binding regions are G/C-rich and are located around transcriptional start sites (TSS) of many protein-coding genes, which in most cases are active, but are not always regulated upon transient mutp53 depletion. We propose a model which does not only rely on interactions of mutp53 with diverse transcriptional regulators at active promoters, but primarily is based on a DNA binding activity of mutp53. We designed a Nimblegen custom 135k tiling array that covers a large set of putative and known p53 (wild-type and mutant) target genes in the human genome. For analysis of the epigenetic state of genes covered by the tiling array in control and mutant p53-depleted U251 cells we focused on changes in active histone marks, H3K4me3 and H3K9Ac, and RNA polymerase II recruitment and processivity. H3K4me3 and H3K9Ac marks are enriched in active promoter regions and the phosphorylation of serine 5 (S5-P) and serine 2 (S2-P) in the CTD of RNA polymerase II have been described to define initiated and elongating complexes, respectively. We performed the ChIP-chip experiments for H3K4me3, H3K9Ac, RNA polymerase II (S5-P) and RNA polymerase II (S2-P) from U251 cells transfected with p53-specific siRNA or control siRNA (2 biological replicates each). To analyze binding of mutant p53 to the genes covered by the tiling array we performed mutant p53 ChIP-chip experiments in 4 biological replicates of. In addition, we analyzed the distribution of SP1 and ETS1 binding sites in 3 biological replicates.
Project description:Using human U251 glioblastoma cells with endogenous mutp53 expression as a model, we performed a ChIP-chip analysis of mutp53 binding sites on a custom tiling array, coupled with global expression profiling and an analysis of the epigenetic status of mutp53 regulated promoters. Mutp53 binds preferentially, and independent of other transcription factors (e.g. ETS1 and SP1), to G/C-rich DNA stretches around transcriptional start sites (TSS) of many genes. Mutp53-bound regions are frequently located in CpG islands and are highly prone to adopt non-B DNA conformation(s). Analysis of the transcriptional status of mutp53-regulated genes demonstrated that mutp53 generally modulates transcription from active promoters marked by H3K4me3. Based on our data we propose a dual mode model of mutp53 GOF, which includes both stochastic and deterministic components. On a local scale, mutp53 acts as a basal transcriptional co-factor that has the potential to bind autonomously and selectively to non-B DNA structures around TSSs of active genes and to modulate transcription rates of many genes in a context and stimulus-dependent fashion. Resulting stochastic alterations generate transcriptional plasticity and enhance transcriptional competence on a global scale. This SuperSeries is composed of the SubSeries listed below. Refer to individual Series