The aim was to identify genes that were commonly influenced by a siRNA targeting PRKCD in breast cancer cell lines.
Down Regulation of CLDND1 Induces Apoptosis in Breast Cancer Cells.
Cell line, Treatment
View SamplesNumerous chromatin-remodelling factors are regulated by interactions with RNA. However, the contexts in which chromatin-remodelling factors encounter various RNA species, as well as the molecular functions of RNA binding, are poorly understood. Here we show that R-loops, RNA:DNA hybrids consisting of nascent transcripts hybridized to template DNA strands, facilitate embryonic stem cell (ESC) differentiation by modulating the binding of two key chromatin-remodelling enzymes near gene promoters. As previously shown for polycomb repressive complex 2 (PRC2)1-5, we find that the Tip60-p400 histone acetyltransferase and nucleosome-remodelling complex binds in cis to nascent transcripts. However, whereas chromatin binding by PRC2 is broadly inhibited by transcription6, transcription is necessary for maximal Tip60-p400 binding at most target loci. Given that nascent transcripts expressed from GC-rich promoters frequently form R-loops7, we mapped the genomic locations of R-loops in mouse ESCs, observing higher average Tip60-p400 levels and lower average PRC2 levels at genes with R-loops near their transcription start sites (TSSs). Disruption of R-loops by overexpression of RNaseH1 broadly reduced Tip60-p400 and increased PRC2 enrichment, demonstrating R-loops exert both positive and negative effects on chromatin association by regulatory factors. Consistent with these findings, RNaseH1 overexpression results in widespread changes in gene expression and inhibits ESC differentiation, allowing undifferentiated cells to persist for at least two weeks after differentiation is induced. These results define a novel mechanism by which promoter-proximal R-loops modulate chromatin structure to facilitate changes in cellular identity. Overall design: We examined the transcriptional profile in control and RNaseH1 overexpression mouse ES cells during differentiation.
R loops regulate promoter-proximal chromatin architecture and cellular differentiation.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Molecular characterization of choroid plexus tumors reveals novel clinically relevant subgroups.
Specimen part
View SamplesGene expression was assessed in a cohort of 40 choroid plexus tumors isolated from fresh-frozen tissue. We investigated unique expression patterns among tumor subgroups and refined the classification of choroid plexus tumors according to gene expression intensities.
Molecular characterization of choroid plexus tumors reveals novel clinically relevant subgroups.
Specimen part
View SamplesTCF7L2 regulates multiple metabolic pathways in hepatocytes through a transcriptional network involving HNF4a Overall design: For the identification of Tcf7l2 target genes using a RNA-seq timecourse, and for identifying the binding sites of Tcf7l2 and Hnf4a, Tcf7l2 was silenced in rat H4IIE hepatocytes using siRNA for Tcf7l2 with a scrambled siRNA as control. Treatment times for RNA-seq samples were 3, 6, 9, 12, 15, 18, 48, and 96 hours, and for ChIP-seq samples 15 h. RNA-seq timecourse was performed in duplicate or triplicate, and the ChIP-seq in duplicate for Tcf7l2 and in singlicate for Hnf4a. The H4IIE-specific transcriptome was defined from an independent set of pooled 24 h siRNA treated samples (N=3 for siRNA for Tcf7l2 and N=3 for scrambled siRNA).
The mechanisms of genome-wide target gene regulation by TCF7L2 in liver cells.
No sample metadata fields
View SamplesThis sudy focuses on the identification of transcripts in the shoot phloem of the model plant Arabidopsis thaliana. Transcripts expressed in the phloem tissue (parenchyma cell, companion cell, sieve element) were excised by laser microdissection pressure catapulting (LMPC). These were compared with transcripts isolated from leaf phloem exudates by EDTA-chelation technique. Optimization of sample harvest resulted in RNA of high quality from both sources. Modifications of the RNA amplification procedure obtained RNA of sufficient yield and quality for microarray experiments. Microarrays (Affymetrix, ATH1) hybridized with RNA derived from phloem tissue by LMPC or phloem sap allowed us to differentiate between phloem located and mobile transcript species. The datasets provide a search criterion for phloem-based signals and will facilitate reverse genetic studies and forward genetic screens for phloem and long distance RNA signaling mutants.
Identification of Arabidopsis thaliana phloem RNAs provides a search criterion for phloem-based transcripts hidden in complex datasets of microarray experiments.
No sample metadata fields
View SamplesHuman cancers result from a complex series of genetic alterations resulting in heterogeneous disease states. Dissecting this heterogeneity is critical for understanding underlying mechanisms and providing opportunities for therapeutics matching the complexity. Mouse models of cancer have generally been employed to reduce this complexity and focus on the role of single genes. Nevertheless, our analysis of tumors arising in the MMTV-Myc model of mammary carcinogenesis reveals substantial heterogeneity, seen in both histological and expression phenotypes. One contribution to this heterogeneity is the substantial frequency of activating Ras mutations, the frequency of which can be changed by alterations in Myc. Additionally, we show that these Myc-induced mammary tumors exhibit even greater heterogeneity, revealed by distinct histological subtypes as well as distinct patterns of gene expression, than many other mouse models of tumorigenesis. Two of the major histological subtypes are characterized by differential patterns of cellular signaling pathways, including B-Catenin and Stat3 activities. We also demonstrate the predictive nature of this approach though examining metastatic potential. Together, these data reveal that a combination of histological and genomic analyses can uncover substantial heterogeneity in mammary tumor formation and therefore highlight aspects of tumor phenotype not evident in the population as a whole.
Genetic heterogeneity of Myc-induced mammary tumors reflecting diverse phenotypes including metastatic potential.
No sample metadata fields
View SamplesIdentification of genes that are involved in self-seeding by comparing gene expression profiles between parental MDA-MB-231 cells and seeder cells (MDA-231-S1a and S1b)
Tumor self-seeding by circulating cancer cells.
No sample metadata fields
View SamplesMetastasis to lymph nodes is an early and prognostically important event in the progression of many human cancers, and is associated with expression of vascular endothelial growth factor-D (VEGF-D). Changes to lymph node vasculature occur during metastasis, and may establish a metastatic niche capable of attracting and supporting tumor cells.
A role for bone morphogenetic protein-4 in lymph node vascular remodeling and primary tumor growth.
Sex, Specimen part
View SamplesExploring the novel role of RORC (RORgamma) in breast cancer, utilizing NEXTseq with genetic gain and loss of function and pharmacological treatment. Overall design: For loss of function, control-siRNA or RORC-siRNA was transfected for 48h in three cell lines (MCF-7, T-47D and MDA-MB-231). For gain of function, CMV-empty or CMV-RORC was transfected for 48h in MDA-MB-231 cells. Furthermore, the selective RORC antagonist, SR2211 was utilized. MCF-7 cells were treated either DMSO or SR2211 (5uM) for 24h. Total RNA was extracted with the RNeasy kit. NEXTseq was performed for transcriptome analysis.
The Nuclear Receptor, RORγ, Regulates Pathways Necessary for Breast Cancer Metastasis.
No sample metadata fields
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