The first described feedback loop of the Arabidopsis circadian clock is based on reciprocal regulation between TOC1 and CCA1/LHY. CCA1 and LHY are MYB transcription factors that bind directly to the TOC1 promoter to negatively regulate its expression. Conversely, the activity of TOC1 has remained less well characterized. Genetic data supports that TOC1 is necessary for the reactivation of CCA1/LHY, but there is little description of its biochemical function. Here we show that TOC1 occupies specific genomic regions in the CCA1 and LHY promoters. Purified TOC1 binds directly to DNA through its CCT domain, which is similar to known DNA binding domains. Chemical induction and transient overexpression of TOC1 in Arabidopsis seedlings cause repression of CCA1/LHY expression demonstrating that TOC1 can repress direct targets, and mutation or deletion of the CCT domain prevents this repression showing that DNA binding is necessary for TOC1 action. Furthermore, we use the Gal4/UAS system in Arabidopsis to show that TOC1 acts as a general transcriptional repressor, and that repression activity is in the Pseudoreceiver (PR) domain of the protein. To identify the genes regulated by TOC1 on a genomic scale, we couple TOC1 chemical induction with microarray analysis and identify new potential TOC1 targets and output pathways. Together these results define the biochemical action of the core clock protein TOC1 and refine our perspective on how plant clocks function.
Arabidopsis circadian clock protein, TOC1, is a DNA-binding transcription factor.
No sample metadata fields
View SamplesMalignant gliomas constitute one of the most significant areas of unmet medical need, due to the invariable failure of surgical eradication and their marked molecular heterogeneity. Accumulating evidence has revealed a critical contribution by the Polycomb axis of epigenetic repression. However, a coherent understanding of the regulatory networks affected by Polycomb during gliomagenesis is still lacking. Here we integrate transcriptomic and epigenomic analyses to define Polycomb-dependent networks that promote gliomagenesis, validating them both in two independent mouse models and in a large cohort of human samples. We found that Polycomb dysregulation in gliomagenesis affects transcriptional networks associated to invasiveness and de-differentiation. The dissection of these networks uncovers Zfp423 as a crtitical Polycomb-dependent transcription factor whose silencing negatively impacts survival. The anti-gliomagenic activity of Zfp423 requires interaction with the SMAD proteins within the BMP signaling pathway, pointing to a novel synergic circuit through which Polycomb inhibits BMP signaling. Overall design: Transcriptomic analysis of two different stages of gliomagenesis
Polycomb dysregulation in gliomagenesis targets a Zfp423-dependent differentiation network.
Specimen part, Cell line, Subject
View SamplesA catalytic role has been proposed in neoplastic angiogenesis and cancer progression for bone marrow-derived endothelial progenitor cells (EPCs). However, in preclinical and clinical studies the quantitative role of marrow-derived EPCs in cancer vascularization was found to be extremely variable. Adipose tissue represents an attractive source of autologous adult stem cells due to its abundance and surgical accessibility. CD34+cells from Lipotransfer aspirates (LAs) of patients undergoing breast reconstruction after breast cancer surgery were compared with CD34+ cells from Leucapheresis of normal subjects.
The white adipose tissue used in lipotransfer procedures is a rich reservoir of CD34+ progenitors able to promote cancer progression.
Sex
View SamplesGlobal gene expression of 13 frozen samples, 6 from typical and 7 from atypical surgically resected primary lung carcinoids
Gene expression profiling reveals GC and CEACAM1 as new tools in the diagnosis of lung carcinoids.
Sex
View SamplesUsing a dataset of 54 pregnant and 113 age/stage-matched non-pregnant breast cancer patients with complete clinical and survival data; we evaluated the pattern of hot spot somatic mutations and performed transcriptomic profiling using Sequenom and Affymetrix, respectively. Breast cancer molecular subtypes were defined using PAM50 and 3-Gene classifiers. We performed Gene set enrichment analysis (GSEA) to evaluate pathways associated with diagnosis during pregnancy. We investigated the differential expression of cancer-related genes and published gene sets according to pregnancy. We finally investigated genes associated with disease-free survival.
Biology of breast cancer during pregnancy using genomic profiling.
Age, Disease stage
View SamplesTranscription factor (TF)-induced reprogramming of somatic cells into induced pluripotent stem cells (iPSC) is associated with genome-wide changes in chromatin modifications. Polycomb-mediated histone H3 lysine-27 trimethylation (H3K27me3) has been proposed as a defining mark that distinguishes the somatic from the iPSC epigenome. Here, we dissected the functional role of H3K27me3 in TF-induced reprogramming through the inactivation of the H3K27 methylase EZH2 at the onset of reprogramming. Our results demonstrate that surprisingly the establishment of functional iPSC proceeds despite global loss of H3K27me3. iPSC lacking EZH2 efficiently silenced the somatic transcriptome and differentiated into tissues derived from the three germ layers. Remarkably, the genome-wide analysis of H3K27me3 in Ezh2 mutant iPSC cells revealed the retention of this mark on a highly selected group of Polycomb targets enriched for developmental regulators controlling the expression of lineage specific genes. Erasure of H3K27me3 from these targets led to a striking impairment in TF-induced reprogramming. These results indicate that PRC2-mediated H3K27 trimethylation is required on a highly selective core of Polycomb targets whose repression enables TF-dependent cell reprogramming.
Cell reprogramming requires silencing of a core subset of polycomb targets.
Specimen part
View SamplesThis series of microarray experiments contains the gene expression profiles of purified plasma cells (PCs) obtained from 7 monoclonal gammopathy of undetermined significance (MGUS), 39 newly diagnosed multiple myeloma (MM) and 6 plasma-cell leukaemia (PCL) patients. PCs were purified from bone marrow Seriess, after red blood cell lysis with 0.86% ammonium chloride, using CD138 immunomagnetic microbeads. The purity of the positively selected PCs was assessed by morphology and flow cytometry and was > 90% in all cases. 5 micrograms of total RNA was processed and hybridized to the Affymetrix HG-U133A chip following the manufacturer's instructions. After scanning, the images were processed using Affymetrix MicroArray Suite (MAS) 5.0 software to generate gene expression intensity values. Arrays normalization was performed using MAS 5.0 "global scaling" procedure, which normalizes the signals of different experiments to the same target intensity (TGT=100).
Gene expression profiling of plasma cell dyscrasias reveals molecular patterns associated with distinct IGH translocations in multiple myeloma.
No sample metadata fields
View SamplesAmong B-cell lymphomas mantle cell lymphoma (MCL) has the worst prognosis. By using a combination of genomic and expression profiling (Affymetrix GeneChip Mapping 10k Xba131 and U133 set), we analysed 26 MCL samples to identify genes relevant to MCL pathogenesis and that could represent new therapeutic targets. Recurrent genomic deletions and gains were detected. Genes were identified as overexpressed in regions of DNA gain on 3q, 6p, 8q, 9q, 16p and 18q, including the cancer genes BCL2 and MYC. Among the transcripts with high correlation between DNA and RNA, we identified SYK, a tyrosine kinase involved in B-cell receptor signalling. SYK was amplified at DNA level, as validated by fluorescence in situ hybridisation (FISH) analysis, and overexpressed at both RNA and protein levels in the JeKo-1 cell line. Low-level amplification, with protein overexpression of Syk was demonstrated by FISH in a small subset of clinical samples. After treatment with low doses of the Syk inhibitor piceatannol, cell proliferation arrest and apoptosis were induced in the cell line overexpressing Syk, while cells expressing low levels of Syk were much less sensitive. A combination of genomic and expression profiling suggested Syk inhibition as a new therapeutic strategy to be explored in lymphomas.
Genomic and expression profiling identifies the B-cell associated tyrosine kinase Syk as a possible therapeutic target in mantle cell lymphoma.
No sample metadata fields
View SamplesApproximately 30% of women diagnosed with ERa breast cancer relapse with metastatic disease following adjuvant treatment with endocrine therapies. The connection between acquisition of drug resistance and invasive potential is poorly understood. In this study, we demonstrate that the type II keratin topological associating domain (TAD) undergoes epigenetic reprogramming in cells that develop resistance to aromatase inhibitors (AI), leading to keratin 80 (KRT80) upregulation. In agreement, an increased number of KRT80-positive cells are observed at relapse in vivo while KRT80 expression associates with poor outcome using several clinical endpoints. KRT80 expression is driven by de novo enhancer activation by sterol regulatory element-binding protein 1 (SREBP1). KRT80 upregulation directly promotes cytoskeletal rearrangements at the leading edge, increased focal adhesion maturation and cellular stiffening, which collectively promote cancer cell invasion. Shear-wave elasticity imaging of tumors from prospectively recruited patients shows that KRT80 levels correlate with stiffer tumors in vivo. Collectively, our data uncover an unpredicted and potentially targetable direct link between epigenetic and cytoskeletal reprogramming promoting cell invasion in response to chronic AI treatment. Overall design: Total RNA profiling of MCF7 breast adenocarcinoma cell line and MCF7 overexpressing KRT80. Experiments were carried out in four replicates in both cell lines.
SREBP1 drives Keratin-80-dependent cytoskeletal changes and invasive behavior in endocrine-resistant ERα breast cancer.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
7q11.23 dosage-dependent dysregulation in human pluripotent stem cells affects transcriptional programs in disease-relevant lineages.
Sex, Specimen part, Subject
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