We propose the hypothesis that loss of estrogen receptor function which leads to endocrine resistance in breast cancer, also results in de-differentiation from an epithelial to a mesenchymal phenotype that is responsible for increased aggressiveness and metastatic propensity. siRNA mediated silencing of the estrogen receptor in MCF7 breast cancer cells resulted in estrogen/tamoxifen resistant cells (pII) with altered morphology, increased motility with rearrangement and switch from an actin to a vimentin based cytoskeleton, and ability to invade simulated components of the extracellular matrix. Phenotypic profiling using an Affymetrix Human Genome U133 plus 2.0 GeneChip indicated fold changes 3 in approximately 2500 identifiable unique sequences, with about 1270 of these being up-regulated in pII cells. Changes were associated with genes whose products are involved in cell motility, loss of cellular adhesion and interaction with the extracellular matrix. Selective analysis of the data also showed a shift from luminal to basal cell markers and increased expression of a wide spectrum of genes normally associated with mesenchymal characteristics, with consequent loss of epithelial specific markers. Over-expression of several peptide growth factors and their receptors are indicative of an increased contribution to the higher proliferative rates of pII cells as well as aiding their potential for metastatic activity. Signalling molecules that have been identified as key transcriptional drivers of epithelial to mesenchymal transition were also found to be elevated in pII cells. We suggest that these data support our hypothesis that induced loss of estrogen receptor in previously antiestrogen sensitive cells is a trigger for the concomitant loss of endocrine dependence and onset of a series of possibly parallel events that changes the cell from an epithelial to a mesenchymal type. Inhibition of this transition through targeting of specific mediators may be a useful supplementary strategy to circumvent the effects of loss of endocrine sensitivity.
Estrogen receptor silencing induces epithelial to mesenchymal transition in human breast cancer cells.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Reconstruction of gene regulatory networks reveals chromatin remodelers and key transcription factors in tumorigenesis.
Specimen part, Cell line
View SamplesThe seed coat of black (iRT) soybean with the dominant R allele begins to accumulate cyanic pigments at the transition stage of seed development (300 400 mg fresh seed weight), whereas the brown (irT) nearly-isogenic seed coat with the recessive r allele lacks cyanic pigments at all stages of seed development.
Combined analysis of transcriptome and metabolite data reveals extensive differences between black and brown nearly-isogenic soybean (Glycine max) seed coats enabling the identification of pigment isogenes.
Specimen part
View SamplesThe mechanistic links between transcription factors and the epigenetic landscape, which coordinate the deregulation of gene networks during cell transformation are largely unknown. We used an isogenic model of stepwise tumorigenic transformation of human primary cells to monitor the progressive deregulation of gene networks upon immortalization and oncogene-induced transformation. By combining transcriptome and epigenome data for each step during transformation and by integrating transcription factor (TF) - target gene associations, we identified 142 Tfs and 24 chromatin remodelers/modifiers (CRMs), which are preferentially associated with specific co-expression paths that originate from deregulated gene programming during tumorigenesis. These Tfs are involved in the regulation of divers processes, including cell differentiation, immune response and establishment/modification of the epigenome. Unexpectedly, the analysis of chromatin state dynamics revealed patterns that distinguish groups of genes, which are not only co-regulated but also functionally related. Further decortication of TF targets enabled us to define potential key regulators of cell transformation, which are engaged in RNA metabolism and chromatin remodelling. Our study suggests a direct implication of CRMs in oncogene-induced tumorigenesis and identifies new CRMs involved in this process. This is the first comprehensive view of gene regulatory networks that are altered during the process of stepwise human cellular tumorigenesis in a virtually isogenic system.
Reconstruction of gene regulatory networks reveals chromatin remodelers and key transcription factors in tumorigenesis.
Specimen part, Cell line
View SamplesDevelopment is a complex and well-defined process characterized by rapid cell proliferation and apoptosis. At this stage in life, a developmentally young organism is more sensitive to toxicants and other stressors when compared to an adult. In response to pro-oxidant exposure, members of the Cap’n’Collar (CNC) basic leucine zipper (b-ZIP) transcription factor family (including the Nfe2-related factors, Nrfs) activate the expression of genes that contribute to reduced toxicity. Here, we studied the role of the Nrf protein, Nfe2, in the developmental response to pro-oxidant exposure in the zebrafish. Following acute waterborne exposures to diquat or tert-buytlhydroperoxide (tBOOH) at three developmental stages, wildtype (WT) and nfe2 knockout (KO) embryos and larvae were morphologically scored and their transcriptomes sequenced. Overall design: Wildtype animals were on the AB background and an additional germline nfe2 knockout strain were created by disruption of the nfe2 reading frame. Waterborne exposures to either diquat or tBOOH were carried out at three different developmental stages: 2 hours post fertilization (hpf), 48hpf, and 96hpf in 3 pools of 30 embryos per condition. Animals were exposed to no treatment, 20µM diquat or 1mM tBOOH for a 4-hour dosing period. Total RNA was isolated from pooled animals and 50 bp, paired end, libraries were sequenced using the Illumina HiSeq 2000 platform, with approximately 25 million reads per sample. Reads were then aligned to the Ensembl GRCz10 zebrafish reference genome using Tophat2 and raw counts data normalized using DESeq2. Gene annotation was from Ensemble for GRCz10.
The transcription factor, Nuclear factor, erythroid 2 (Nfe2), is a regulator of the oxidative stress response during Danio rerio development.
No sample metadata fields
View SamplesHigh grade serous ovarian cancers (HGSC) are deadly malignancies that relapse despite carboplatin chemotherapy. Here we show that 16 independent primary HGSCs contain a CA125 negative population enriched for carboplatin resistant cancer initiating cells. Transcriptome analysis reveals up-regulation of homologous recombination DNA repair and anti-apoptotic signals in this population. While treatment with carboplatin enriches for CA125 negative cells, co-treatment with carboplatin and birinapant eliminates these cells in HGSCs expressing high levels of the inhibitor of apoptosis protein cIAP in the CA125 negative population. Birinapant sensitizes CA125 negative cells to carboplatin by mediating degradation of cIAP causing cleavage of caspase-8 and restoration of apoptosis. This co-therapy significantly improved disease free survival in vivo compared to either therapy alone in tumor-bearing mice. These findings suggest that therapeutic strategies that target CA125 negative cells may be useful in the treatment of HGSC. Overall design: mRNA profiles of CA125 positive and negative populations, generated by next generation sequencing of populations FACS isolated from 10 independent dissociated primary human high grade serous ovarian cancers, were compared.
An apoptosis-enhancing drug overcomes platinum resistance in a tumour-initiating subpopulation of ovarian cancer.
No sample metadata fields
View SamplesHigh grade serous ovarian cancers (HGSC) are deadly malignancies that relapse despite carboplatin chemotherapy. Many commercially ovarian cancer cell lines are not good models for HGSC. Here we demonstrate that 3 low passage cell lines derived from HGSC have similar transcriptomes to their parental bulk tumors. These cell lines recapitulated tumor characteristics of the primary cancer and had responded to therapy in the same manner as primary HGSC cells, demonstrating they are accurate models for HGSCs. Overall design: mRNA profiles of low passage high grade serous tumor cell lines and their parental tumors, generated by next generation sequencing, were compared.
An apoptosis-enhancing drug overcomes platinum resistance in a tumour-initiating subpopulation of ovarian cancer.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Reconstructed cell fate-regulatory programs in stem cells reveal hierarchies and key factors of neurogenesis.
Specimen part, Time
View SamplesWe have integrated dynamic RXRa binding, chromatin accessibility and promoter epigenetic status with the transcriptional activity inferred from RNA polymerase II mapping and transcription profiling. This demonstrated a temporal organization structure, in which early events are preferentially enriched for common GRNs, while cell fate specification is reflected by the activation of late programs in a cell-type specific manner. Furthermore, significant differences in cell lines' promoter status of genes associated with cell-line specific programs were inferred. Finally, a variety of transcription factors (TFs) playing a direct role in the signal transduction cascade downstream of the RXR/RAR initiated wiring were identified, several of them commonly regulated in both model systems, but in addition cell-type specific TF drivers were also identified.
Reconstructed cell fate-regulatory programs in stem cells reveal hierarchies and key factors of neurogenesis.
Specimen part, Time
View SamplesWe studied adipose tissue from wild type mice, kinin B1 receptor knockout mice (B1KO), and B1KO mice with rescued expression of kinin B1 receptor selectively in fat.
Kinin B1 and B2 receptor deficiency protects against obesity induced by a high-fat diet and improves glucose tolerance in mice.
Sex, Age, Specimen part
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