Expression data from Glioma-Initiating Cells (GICs) cultured under hypoxia and normoxia
Ontology highlight
ABSTRACT: Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adults, with glioma initiating cells (GICs) implicated to be critical for tumor progression and resistance to therapy. The hypoxic tumor microenvironment has been shown to play an important role to maintain the GICs; however, the mechanisms regulating responses of GICs to hypoxia remain poorly understood. We used microarray to to detail the global change of gene expression in GICs cultured under hypoxia compared to normoxia and identified de-regulated genes during hypoxia. CD133+ D456MG GICs were cultured under 1% O2 or 20% O2 for 12 hours. Then RNA was extracted and gene expression was profiled by microarray.
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.
Project description:Hypoxia promotes an aggressive tumor phenotype with increased genomic instability, partially due to downregulation of DNA repair pathways. However, in addition to DNA repair, genome stability is also controlled by cell cycle checkpoints. An important issue is therefore whether hypoxia also can alter the DNA damage cell cycle checkpoints. Here, we show that hypoxia (24h 0.2% O2) alters the expression of several G2 checkpoint regulators, as examined by microarray gene expression analysis and immunoblotting of U2OS cells. While some of the changes reflected hypoxia-induced inhibition of cell cycle progression, flow cytometric bar-coding analysis of individual cells showed that the levels of several G2 checkpoint regulators were reduced in G2 phase cells after hypoxic exposure, in particular cyclin B1. These effects were accompanied by decreased Cyclin dependent kinase (CDK) activity in G2 phase cells after hypoxia. Furthermore, cells pre-exposed to hypoxia showed a longer G2 checkpoint arrest upon treatment with ionizing radiation. Similar results were found following other hypoxic conditions (~0.03 % O2 20h and 0.2% O2 72h). These results demonstrate that the DNA damage G2 checkpoint can be altered as a consequence of hypoxia, and we propose that such alterations may influence the genome stability of hypoxic tumors. We measured gene expression changes in U2OS cells after treatment with 0.2% hypoxia for 24 hours. The data were used in the exploration of hyopxia induced alterations in the G2 checkpoint.
Project description:Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adults, with glioma initiating cells (GICs) implicated to be critical for tumor progression and resistance to therapy. The hypoxic tumor microenvironment has been shown to play an important role to maintain the GICs; however, the mechanisms regulating responses of GICs to hypoxia remain poorly understood. We used microarray to to detail the global change of gene expression in GICs cultured under hypoxia compared to normoxia and identified de-regulated genes during hypoxia.
Project description:To delineate the role of hypoxia in esophageal epithelial biology, we carried out gene array experiments using a non-transformed immortalized diploid human esophageal cell line, EPC2-hTERT (Mol Cancer Res. 2003;1:729-38). Unlike cancer cell lines, EPC2-hTERT has no genetic alterations at early passages that may affect the cellular response to hypoxia. Experiment Overall Design: EPC2-hTERT cells were exposed to moderate (1% O2) hypoxia in experiment 1 (Exp1) or severe (0.2% O2) hypoxia in experiment 2 (Exp2). Normoxia (21% O2) served as a control in both experiments.
Project description:Loss of tumor suppressor proteins, such as the retinoblastoma protein (Rb), results in tumor progression and metastasis. Metastasis is facilitated by low oxygen availability within the tumor that is detected by hypoxia inducible factors (HIFs). The HIF1 complex, HIF1α and dimerization partner the aryl hydrocarbon receptor nuclear translocator (ARNT), is the master regulator of the hypoxic response. Previously, we demonstrated that Rb represses the transcriptional response to hypoxia by virtue of its association with HIF1. In this report, we further characterized the role of Rb in HIF1-regulated genetic programs by stably ablating Rb expression with retrovirally-introduced short hairpin RNA in LNCaP and 22Rv1 human prostate cancer cells. DNA microarray analysis revealed that Rb regulates specific chromosomal gene clusters and loss of Rb in conjunction with hypoxia leads to dysregulation of HIF1-regulated genetic programs that increase cell invasion and promote neuroendocrine differentiation. For the first time, we have established a direct link between hypoxic tumor environments, Rb inactivation and progression to late stage metastatic neuroendocrine prostate cancer. Understanding the molecular pathways responsible for progression of benign prostate tumors to metastasized and lethal forms will aid in the development of more effective prostate cancer therapies. RNAs derived from human LNCaP cells stably infected with either scrambled control shRNA or a shRNA directed to RB1. Cells were exposed to either 24 h hypoxia (1% O2) or maintained under normoxic conditions. Biological triplicates were tested and compared.
Project description:Analyze miRNA expression levels in primary trophoblasts, derived from term human placenta and cultured under standard or hypoxic conditions Human placental trophoblasts were dispersed using a trypsin-deoxyribonuclease-dispase/Percoll method, plated in 6-well plates, and maintained in standard culture conditions (O2=20%). After 4 h (defined as time 0), the plates were divided to those in continued standard culture conditions, or to culture in hypoxia (O2=0%). Cells were then harvested at 6 h, 12 h, 24 h, 48 h and 72 h, and processed for miRNA arrays
Project description:Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adults, with glioma initiating cells (GICs) implicated to be critical for tumor progression and resistance to therapy. KDM1B is involved in regulating GICs' responses to hypoxia, since over-expression of KDM1B delays the cell growth under hypoxia while knocking-down of KDM1B in GICs promotes their survival and tumorigenic abilities.
Project description:Analysis of 5-hydroxymethylcytosine changes in hypoxia in neuroblastoma cells 5-hmC distribution was analyzed from cells exposed to hypoxia (1% O2) or normoxia (20% O2); mRNA was sequenced in parallel for expression analysis.
Project description:Transcriptional profiling of H1299 non-small cell lung carcinoma cells transfected with either wt p53 or mut(175) p53 driven by the 5xHRE promoter (5 repeats of hypoxia-inducible factor response elements) and treated for 16 h with normoxia (21% O2) or hypoxia(<0.1% O2). 5xHRE promoter ensures that p53 expression is induced in hypoxic conditions only. Goal was to determine the transcriptional response of p53 in hypoxia and the 175 p53 mutant was used as a control as it is DNA-binding defective and transcription-incompetent mutant. Four-condition experiment: wt p53-transfected H1299 cells treated with normoxia, mut p53-transfected H1299 cells treated with normoxia, wt p53-transfected H1299 cells treated with hypoxia, mut p53-transfected H1299 cells treated with hypoxia. Biological replicates: 1 normoxic sample with wt p53, 1 normoxic sample with mut p53, 3 hypoxic samples with wt p53, 3 hypoxic samples with mut p53.
Project description:Early development of mammalian embryos occurs in an environment of relative hypoxia. Nevertheless, human embryonic stem cells (hESC), which are derived from the inner cell mass of blastocyst, are routinely cultured under the same atmospheric conditions (21% O2) as somatic cells. We hypothesized that O2 levels modulate gene expression and differentiation potential of hESC, and thus, we performed gene profiling of hESC maintained under normoxic or hypoxic (1% or 5% O2) conditions. Our analysis revealed that hypoxia downregulates expression of pluripotency markers in hESC but increases significantly the expression of genes associated with angio- and vasculogenesis including vascular endothelial growth factor and angiopoitein-like proteins. Consequently, we were able to efficiently differentiate hESC to functional endothelial cells (EC) by varying O2 levels; after 24 hours at 5% O2, more than 50% of cells were CD34+. Transplantation of resulting endothelial-like cells improved both systolic function and fractional shortening in a rodent model of myocardial infarction. Moreover, analysis of the infarcted zone revealed that transplanted EC reduced the area of fibrous scar tissue by 50%. Thus, use of hypoxic conditions to specify the endothelial lineage suggests a novel strategy for cellular therapies aimed at repair of damaged vasculature in pathologies such as cerebral ischemia and myocardial infarction. 26 samples in a time course experiment. Gene expression is measured at 5 different time points and under 3 different oxygen levels. Two control samples are provided.