Filters
Technology
Platform
GSE41296
Homo sapiens
120 Downloadable Samples
Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Gene expression analysis has been established as a tool for the characterization of genotoxic mechanisms of chemical mutagens. This approach has been shown to differentiate between DNA reactive genotoxins and non-DNA reactive or indirectly-acting genotoxins. In this context, it has been suggested that expression analysis is capable of distinguishing compounds that cause DNA damage from those that interfere with mitotic spindle function. Formaldehyde (FA) is known to be a DNA-reactive substance which mainly induces chromosomal damage in cultured mammalian cells. However, there has been concern that FA might also act as an aneugen (i.e., induce aneuploidy) but recent cytogenetic studies did not support this assumption. To further characterize FA's genotoxic mode of action, we now used gene expression profiling as a molecular tool to differentiate between clastogenic and aneugenic activity. TK6 cells were exposed to FA for 4 and 24 h and changes in gene expression were analyzed using a whole-genome human microarray. Results were compared to the expression profiles of two DNA-damaging clastogens (methyl methanesulfonate [MMS] and ethyl methanesulfonate [EMS]) and two aneugens (colcemid [COL] and vincristine [VCR]). The gene expression profiles indicated that clastogens and aneugens induce discriminable gene expression patterns. The expression profile of FA showed more similarities to clastogens than to aneugens. Hierarchical clustering analysis as well as several class prediction algorithms revealed a much closer relationship of FA with clastogens than with aneugens. A pathway analysis of differentially regulated genes also demonstrated an overall better agreement of FA with clastogens than with aneugens. Altogether, the results of this study revealed great similarities in gene expression in response to FA and clastogens but did not support an aneugenic activity of FA.
Publication Title
Characterization of formaldehyde's genotoxic mode of action by gene expression analysis in TK6 cells.
Sample Metadata Fields
Cell line, Treatment
View Samples- Homo sapiens
- 36 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Using various exposure conditions, we studied the induction of DNA-protein crosslinks (DPX) by formaldehyde (FA) and their removal in primary human nasal epithelial cells (HNEC). DPX were indirectly measured by the alkaline comet assay as the reduction of gamma ray induced DNA migration. DPX are the most relevant primary DNA alterations induced by FA and the comet assay is a very sensitive method for the detection of FA-induced DPX. In parallel experiments, we investigated changes in gene expression by using a full genome human microarray. After a single treatment with FA (50 to 200 M), concentration and time-dependent changes in gene expression were seen under conditions that also induced genotoxicity. Repeated treatments with low FA concentrations (20 and 50 M) did not lead to a significant induction of DPX but repeated treatments with 50 M FA changed the expression of more than 100 genes. Interestingly, the expression of genes involved in the main pathway for FA detoxification and the repair of DPX were not specifically enhanced. A high degree of overlap was seen among the pattern of gene changes induced by FA in HNEC in comparison to recently published array studies for nasal epithelial cells from rats exposed to FA in vivo. Our results suggest that HNEC are a suited in vitro model for the characterization of FA-induced toxicity and the relationship between genotoxic and other cytotoxic effects.
Publication Title
Gene expression changes in primary human nasal epithelial cells exposed to formaldehyde in vitro.
Sample Metadata Fields
Specimen part, Treatment
View Samples- Homo sapiens
- 92 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
41 volunteers (male non-smokers) were exposed to formaldehyde (FA) vapors for 4 h per day over a period of 5 working days under strictly controlled conditions. For each exposure day, different exposure concentrations were used in a random order ranging from 0 up to 0.7 ppm. At concentrations of 0.3 ppm and 0.4 ppm, four peaks of 0.6 or 0.8 ppm for 15 min each were applied. During exposure, subjects had to perform bicycle exercises (about 80 W) four times for 15 min. Blood samples, exfoliated nasal mucosa cells and nasal biopsies were taken before the first and after the last exposure. Nasal epithelial cells were additionally sampled 1, 2 and 3 weeks after the end of the exposure period. The alkaline comet assay, the sister chromatid exchange (SCE) test and the cytokinesis-block micronucleus test (CBMNT) were performed with blood samples. The micronucleus test (MNT) was also performed with exfoliated nasal mucosa cells. The expression (mRNA level) of the GSH-dependent formaldehyde dehydrogenase (FDH, identical to alcohol dehydrogenase 5; ADH5; EC 1.2.1.46) was measured in blood samples by quantitative real-time RT-PCR with TaqMan probes. DNA microarray analyses using a full-genome human microarray were performed on blood samples and nasal biopsies of selected subgroups with the highest FA exposure at different days. None of the tests performed showed a biologically significant effect related to FA exposure. Under the experimental conditions of this study, inhalation of FA did not lead to genotoxic effects in peripheral blood cells and nasal mucosa and had no effect on the expression of the FDH gene. Inhalation of FA also did not cause biologically relevant alterations in the expression of genes in a microarray analysis with nasal biopsies and peripheral blood cells.
Publication Title
Assessment of genotoxic effects and changes in gene expression in humans exposed to formaldehyde by inhalation under controlled conditions.
Sample Metadata Fields
Sex, Specimen part, Treatment, Subject
View Samples- Arabidopsis thaliana
- 6 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
Sulfite reductase (SiR) plays an essential role in the assimilatory sulfur reduction pathway by catalyzing the reduction of sulfite to sulfide. The T-DNA insertion mutant line sir1-1 shows lower amounts of SiR transcript, protein and lower activity and is severely affected in growth. In this study we performed global transcriptome analysis to investigate the impact of the mutation in the shoot of 7-week-old plants.
Publication Title
Sulfur availability regulates plant growth via glucose-TOR signaling.
Sample Metadata Fields
Age
View Samples- Rattus norvegicus
- 45 Downloadable Samples
- Affymetrix Rat Gene 1.1 ST Array (ragene11st)
Description
Introduction: Renal ischemia-reperfusion (IR) causes acute kidney injury (AKI) with high mortality and morbidity. The objective of this study was to ameliorate kidney IR injury and identify novel biomarkers for kidney injury and repair. Methods: Left renal ischemia was induced in rats by clamping renal artery for 45 minutes, followed by reperfusion and right nephrectomy. Thirty minutes prior to ischemia, rats (n=8/group) received Valproic Acid (150 mg/kg; VPA), Dexamethasone (3 mg/kg; Dex) or Vehicle (Saline) intraperitoneally. Animals were sacrificed at 3h, 24h or 120h post- IR and blood, urine and kidney were collected. Results: Serum creatinine (mg/dL) at 24 h IR in VPA (2.71.8) and Dex (2.31.2) was reduced (P<0.05) compared to Vehicle (3.80.5). At 3h post-IR, urine albumin (mg/ml) was higher in Vehicle (1.470.10), VPA (0.840.62) and Dex (1.040.73) compared to uninjured/untreated control (0.140.26) group. At 24h post-IR urine Lipocalin-2 (g/ml) was significantly higher (P<0.05) in VPA, Dex and Vehicle groups (9.61-11.36) compared to uninjured/untreated control (0.67o.29); also, Kidney Injury Molecule-1 (KIM-1; ng/ml) was significantly higher in VPA, Dex and Vehicle groups (13.7-18.7) compared uninjured/untreated control (1.71.9). KIM-1 levels were significantly (P<0.05) higher in all groups compared to uninjured/untreated control levels. Histopathology at 3h post IR demonstrated (P<0.05) reduction in ischemic injury in the renal cortex in VPA (Grade 1.6 1.5) compared to Vehicle (Grade 2.91.1) group. Inflammatory cytokines IL1 and IL6 were down-regulated in VPA and Dex groups. BCL2 was higher in VPA group. DNA microarray analysis demonstrated reduced stress response and injury, and improved recovery related gene expression in the kidneys of VPA treated animals. Conclusions: VPA administration reduced kidney IR injury and improved regeneration. KIM-1 and Lipocalin-2 appear to be promising early urine biomarkers of acute ischemic kidney injury.
Publication Title
Effects of valproic acid and dexamethasone administration on early bio-markers and gene expression profile in acute kidney ischemia-reperfusion injury in the rat.
Sample Metadata Fields
Sex, Specimen part, Treatment
View Samples- Homo sapiens
- 6 Downloadable Samples
- Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
Combination of platinum-based chemotherapy and radiation is currently the standard treatment for locally advanced lung cancer patients. However, therapeutic resistance to these therapies may arise from the presence of cancer stem cells (CSCs). To investigate the CSCs hypothesis of chemo-radiation resistance, we used microarray assay to profile CSCs-like cisplatin-resistant lung cancer cells (CDDP-R) versus its parental cells. CDDP-R cells were established by exposing H460 lung cancer cells to 3M cisplatin for 7 days, followed by 0.8% methylcellulose selection over 14 consecutive days.We found that CDDP-R cells expressed higher levels of stem cell markers, including CD133 and ALDH. They are more resistant to cisplatin- and etoposide-induced apoptosis and to high radiation dose (20Gy). Clonogenic assays suggest that CDDP-R cells were more resistant to radiation than parental H460 cells (DER=1.21, p<0.01). Xenograft studies suggest that CDDP-R cells were more tumorigenic (p<0.001). Microarray and comprehensive protein interaction networks analyses revealed IGFBP3 as a highly ranked hub protein which plays an important role in the mechanism of cisplatin resistance. We found reduced level of IGFBP3 and enhanced IGFR-1 activation upon IGF stimulation in CDDP-R cells. The specific targeting of IGF-1R using siRNA resulted in significant sensitization of CDDP-cells (DER=1.17, p<0.05) to radiation compared with the parental H460 cells. Our findings suggest that CDDP-R cells have the characteristics of CSCs and constitute a suitable model to study lung CSCs. Profiling of CSCs-like H460 cells led to the identification of IGF as an important pathway for chemo- and radiotherapy resistance in lung cancer.
Publication Title
Role of insulin-like growth factor-1 signaling pathway in cisplatin-resistant lung cancer cells.
Sample Metadata Fields
Specimen part
View Samples- Homo sapiens
- 6 Downloadable Samples
NextSeq 500
Description
Both p150 and p110 isoforms of ADAR1 convert adenosine to inosine in double-stranded RNA (dsRNA). The p150 isoform suppresses the dsRNA sensing mechanism that activates the interferon induction mediated by the MDA5-MAVS signaling. In contrast, the biological function of the p110 isoform localized in the nucleus remains largely unknown. Here we show that stress-activated phosphorylation of ADAR1p110 by MKK6/p38 MAP kinases promotes its binding to Exportin-5 and nuclear export to the cytoplasm. Once translocated to the cytoplasmic, ADAR1p110 suppresses apoptosis of stressed cells by protecting many anti-apoptotic gene transcripts that contain 3'UTR dsRNA structures such as those consisting of inverted Alu repeats. ADAR1p110 competitively inhibits binding of Staufen1 to the 3'UTR dsRNAs and antagonizes the Staufen1-mediated mRNA decay mechanism. Our studies revealed a new stress response mechanism regulated by MAP kinases, in which ADAR1p110 translocates to the cytoplasm and regulates a class of mRNAs required for survival of stressed cells. Overall design: Examination of transcription changes due to ADAR1 and double ADAR1/STAU1 knockdown using RNA-seq
Publication Title
ADAR1 controls apoptosis of stressed cells by inhibiting Staufen1-mediated mRNA decay.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 2 Downloadable Samples
- NextSeq 500
Description
CARM1 is an arginine methyltransferase that asymmetrically dimethylates protein substrates on arginine residues. CARM1 is often overexpressed in cancers and stimulates growth. However, clinically applicable therapeutic strategies based on CARM1 expression in cancer remains to be explored. Here we show that epithelial ovarian cancer is among the cancers with the highest CARM1 amplification rates that predicates a shorter survival. Our unbiased screen show that CARM1-expressing ovarian cancer cells are selectively sensitive to the inhibition of EZH2, another epigenetic regulator that silences its target genes. Inhibition of EZH2 activity using a clinically applicable small molecule inhibitor significantly suppressed the growth of CARM1-expressing ovarian tumors in two xenograft models. The observed selectivity correlates with upregulation of EZH2 target genes in a CARM1-dependent manner. CARM1 promotes EZH2 dependent gene silencing by methylating BAF155 to alter the antagonism between EZH2 and BAF155. Together, these results indicate that pharmacological inhibition of EZH2 is a novel therapeutic strategy for CARM1-expressing cancers. Overall design: CARM1 wild type and knockout samples assayed by RNA-seq
Publication Title
CARM1-expressing ovarian cancer depends on the histone methyltransferase EZH2 activity.
Sample Metadata Fields
Cell line, Subject
View Samples- Homo sapiens
- 291 Downloadable Samples
- Illumina human-6 v2.0 expression beadchip
Description
We report a 29-gene diagnostic signature, which distinguishes individuals with NSCLC from controls with non-malignant lung disease with 91% Sensitivity, 79% Specificity and a ROC AUC of 92%. Accuracy on an independent set of 18 NSCLC samples from the same location was 79%. Samples from an independent location including 12 stage 1 NSCLC and 15 controls, achieved an accuracy of 74%. A study of 18 paired samples taken pre and post surgery shows that the PBMC associated cancer signature is significantly reduced after tumor removal, supporting the hypothesis that the signature detected in pre-surgery samples is a response to the presence of the tumor.
Publication Title
Gene expression profiles in peripheral blood mononuclear cells can distinguish patients with non-small cell lung cancer from patients with nonmalignant lung disease.
Sample Metadata Fields
Sex, Age, Race
View Samples- Mus musculus
- 24 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Cardiac hypertrophy can lead to heart failure, and is induced either by physiological stimuli eg postnatal development, chronic exercise training or pathological stimuli eg pressure or volume overload. Majority of new therapies for heart failure has mixed outcomes. A combined mouse model and oligo-array approach are used to examine whether phosphoinositide 3-kinase (p110-alpha isoform) activity is critical for maintenance of cardiac function and long-term survival in a setting of heart failure. The significance and expected outcome are to recognise genes involved in models of heart failure ie pathological- vs physiology-hypertrophy, and examine the molecular mechanisms responsible for such activity.
Publication Title
PI3K(p110 alpha) protects against myocardial infarction-induced heart failure: identification of PI3K-regulated miRNA and mRNA.
Sample Metadata Fields
No sample metadata fields
View Samples