Transcription profiling by array of human mammary epithelial cells grown in 2D monolayers with or without EGF and insulin, or 3D Matrigel culture, after treatment with 4-hydroxytamoxifen
ABSTRACT: MCF10A MycER cells were grown either on 2D monolayer culture in the presence of complete growth medium, in the absence of EGF and insulin or in 3D Matrigel culture for 20 days to form acinar structures. MycER was activated with 4-hydroxytamoxifen (4-OHT) in all samples for 2 or 48 h. Control cells were treated with ethanol. The aim of the study was to explore the effect of different growth conditions on gene expression changes in response to c-Myc activation.
Project description:Expression data from ERBB2 over-expression and EGF stimulation in MCF10A cells The cells were transduced with retroviruses encoding vector control (pBabe) or pBabe-ErbB2. After infection cells were switched to assay medium supplemented with only 2% horse serum and no EGF. For EGF stimulation, cells transduced with empty vector were treated with EGF at 50 ng/ml for 2 hours before harvesting.
Project description:Using basal‐like untransformed cells, MCF10A, as a model system, data from our laboratory showed that both mRNAs and microRNAs exhibit dynamic changes in expression following EGF stimulation (Amit et al, 2007; Avraham et al, 2010; Kostler et al, 2013). We further demonstrated that the inducible mRNAs and microRNAs are embedded into regulatory subnetworks, which are deregulated in diverse tumor types. Considering the emerging roles for long noncoding RNAs (lncRNAs) in metastasis of breast cancer (Serviss et al, 2014), we raised the possibility that some EGF‐inducible lncRNAs might play a role in basal‐like breast cancer. Thus, MCF10A cells were stimulated with EGF (10 ng/ml) for 0, 20, 40, 60, 120, 240 and 480 minutes. RNA was then extracted from cells and expression of lncRNAs was measured using Agilent SurePrint microarrays.
Project description:Tumor invasion into surrounding stromal tissue is a hallmark of high-grade, metastatic cancers. Oncogenic transformation of human epithelial cells in culture can be triggered by activation of v-Src kinase, resulting in increased cell motility, invasiveness and tumorigenicity and provides a valuable model for studying how changes in gene expression cause cancer phenotypes. Here, we show that epithelial cells transformed by activated Src show increased levels of DNA methylation and that the methylation inhibitor, 5-AzaC, potently blocks the increased cell motility and invasiveness induced by Src activation. A proteomic screen for chromatin regulators acting downstream of activated Src identified the replication-dependent histone chaperone CAF1 as an important factor for Src-mediated increased cell motility and invasion. We show Src causes a 5-AzaC-sensitive decrease in both mRNA and protein levels of the p150 (CHAF1A) and p60 (CHAF1B), subunits of CAF1. Depletion of CAF1 in untransformed epithelial cells using siRNA was sufficient to recapitulate the increased motility and invasive phenotypes characteristic of transformed cells without activation of Src. Maintaining high levels of CAF1 by exogenous expression suppressed the increased cell motility and invasiveness phenotypes when Src was activated. These data identify a critical role of CAF1 in the dysregulation of cell invasion and motility phenotypes seen in transformed cells and also highlight an important role for epigenetic remodeling through DNA methylation for Src-mediated induction of cancer phenotypes.
Project description:To ensure proper gene regulation within constrained nuclear space, chromosomes facilitate access to transcribed regions, while compactly packaging all other information. Recent studies revealed that chromosomes are organized into megabase-scale domains that demarcate active and inactive genetic elements, suggesting that compartmentalization is important for genome function. Here we show that very specific long-range interactions are anchored by cohesin/CTCF sites, but not cohesin-only or CTCF-only sites, to form a hierarchy of chromosomal loops. These loops demarcate topological domains and form intricate internal structures within them. Post-mitotic nuclei deficient for functional cohesin exhibit global architectural changes associated with loss of cohesin/CTCF contacts and relaxation of topological domains. Transcriptional analysis shows that this cohesin-dependent perturbation of domain organization leads to widespread gene deregulation of both cohesin-bound and non-bound genes. Our data thereby support a role for cohesin in the global organization of domain structure and suggest that domains function to stabilize the transcriptional programs within them. Hi-C, ChIP-Seq and RNA-Seq experiments were conducted in mouse neural stem cells and mouse astrocytes
Project description:Stem cell functions require activation of stem cell-intrinsic transcriptional programs as well as intimate extracellular interactions with a niche microenvironment. How the core pluripotency transcriptional machinery controls residency of stem cells in the niche microenvironment is unknown. Here we show that the helix loop helix transcriptional regulators Id (Inhibitors of DNA binding) are the master regulators that coordinate stem cell activities with anchorage of neural stem cells (NSCs) to the embryonic and postnatal niche. Conditional inactivation of Id genes (Id1, Id2 and Id3) in the mouse NSC compartment triggered detachment of embryonic and post-natal NSCs from the ventricular and vascular niche respectively, followed by premature differentiation. Through an unbiased interrogation of the gene modules directly targeted by deletion of Id genes in NSCs, we discovered that Id proteins repress the bHLH-mediated activation of Rap1GAP, thus serving to maintain the GTPase activity of RAP1, a key mediator of cell adhesion. Preventing the elevation of Rap1GAP efficiently countered the consequences of Id loss on NSC-niche interaction and stem cell identity. Thus, by preserving anchorage to the extracellular environment of NSCs, Id activity synchronizes NSC functions to residency in the specialized niche. We generated Id-cTKO mice carrying a Cre-recombinase-oestrogen-receptor-T2 (Cre-ER) allele targeted to the ubiquitously expressed ROSA26 locus (Id-cTKO-Rosa-Cre-ER). In this system, 4-hydroxytamoxifen (4-OHT) releases the Cre recombinase inhibition and allows recombination of genomic loxP sites. Indeed, efficient deletion of Id1 and Id2 with complete loss of Id protein expression was detectable after treatment of NSCs with 4-OHT for 72 h. Total RNA was extracted from triplicate samples of Id-cTKO-Rosa-Cre-ER NSCs treated for different times (6 h, 12 h, 18 h, 24 h, 48 h, 96 h, 144 h) with 4-OHT or control vehicle and used for analysis on Illumina MouseWG-6 expression BeadChip. The raw array data was normalized using the Bioconductor package Lumi using quantile normalization.
Project description:This SuperSeries is composed of the following subset Series: GSE14987: Expression data from ERBB2 over-expression and EGF stimulation in MCF10A cells GSE14988: Expression data from DHT stimulation vs. control in LNCaP cells Refer to individual Series
Project description:Basal-like carcinoma is a subtype of breast cancer that is characterized by poor prognosis and high intratumor heterogeneity. Using a basal-like breast epithelial line, we have identified two anti-correlated gene-expression programs that arise among single extracellular matrix (ECM)-attached cells during organotypic 3D culture. The first program contains TGFBR3, a high-affinity receptor for transforming growth factor β (TGFβ) and other related ligands. The second program contains the JUND transcription factor together with the basal-like marker, KRT5. By disrupting the TGFBR3 and JUND programs individually, we reveal an important circuit for 3D morphogenesis that is wired together by four negative-feedback loops. Computational modeling of this circuit showed that it could exhibit damped, antiphase oscillations when excited with small impulses of TGFβ-like ligand. We directly visualize the circuit's spontaneous dynamics in organotypic cultures by using live-cell imaging with engineered pathway reporters. Importantly, we show that the essence of the JUND-TGFBR3 expression circuit holds true in early basal-like tumors that heterogeneously express KRT5. Correlated JUND-KRT5 expression depends critically on contact with stromal ECM and local expression of tenascin C. This work illustrates how complex tumor heterogeneities can be deconstructed into intrinsic single-cell expression circuits that are modulated by the microenvironment. Gene expression analysis of outer ECM-attached vs. inner cells of MCF10A-5E clones grown in organotypic 3D culture at day 6. Total RNA was isolated from ~50 outer ECM-attached cells and ~50 inner cells, each separately microdissected from 8 micron sections of MCF10A structures at day 6 of morphogenesis. Total RNA was amplified in quadruplicate, and hybridized to HumanRef-8 v2.0 Expression BeadChips (Illumina).
Project description:Combination therapy with Smo and PI3K inhibitors results in a synergistic effect in reducing tumor growth in PTEN-deficient Glioblastoma. To identify consequences of combination therapy with an Smo inhibitor and a PI3K inhibitor on a genome-wide scale, we performed Affymetrix microarrays with two different PTEN-deficient GBMs treated with single drugs or combination therapy. A small set of genes was significantly affected by combination therapy in hBT70 and/or hBT112, including several genes implicated in GBM prognosis, or identified as targets of Shh, PI3K or S6 pathways 29-33 . There are two different human GBM tumors (BT70 and BT112). Both are PTEN deficient. Samples were treated with DMSO (Control), LDE225 at 1 uM for 5 days, BKM 120 100 nM for 5 days, or LDE225 1 uM and BKM 120 100 nM for 5 days (Combo). Two biological replicates of each condition were analyzed.
Project description:Grainyhead genes are involved in wound healing and developmental neural tube closure. In light of the high degree of similarity between the epithelial-mesenchymal transitions (EMTs) occurring in wound healing processes and the cancer stem cell-like compartment of tumors, including TGF-β-dependence, we investigated the role of a Grainyhead gene (GRHL2) in oncogenic EMT. Grainyhead was specifically down-regulated in the claudin-low subclass of mammary tumors and in the basal-B subclass of breast cancer cell lines. Functionally, GRHL2 suppressed TGF-β-induced, Twist-induced or spontaneous EMT, enhanced anoikis-sensitivity, and suppressed mammosphere generation in mammary epithelial cells. These effects were mediated, in part, by its suppression of ZEB1 expression, through direct repression of the ZEB1 promoter. GRHL2 also inhibited Smad-mediated transcription, and up-regulated mir200b/c as well as the TGF-β receptor antagonist, BMP2. The expression of GRHL2 in the breast cancer cell line MDA-MB-231 triggered a mesenchymal-to-epithelial transition and sensitized the cells to anoikis. These results indicate that GRHL2 is a suppressor of the oncogenic EMT. 3 biologic replicates for each cell line. Comparison of HMLE+Twist-ER cells expressing GRHL2/pMIG vs. HMLE+Twist-ER cells expressing empty pMIG.
Project description:Oncogenic levels of Myc expression sensitize cells to multiple apoptotic stimuli and this protects long-lived organisms from cancer development. How cells discriminate physiological from supra-physiological levels of Myc is largely unknown. Here we show that induction of apoptosis by Myc in breast epithelial cells requires association of Myc with Miz1. Gene expression and ChIP-sequencing experiments show that oncogenic levels of Myc, but not of MycV394D, a point mutant that does not bind Miz1, recruit Miz1 to core promoters and enable binding of Myc/Miz1 complexes to low-affinity target sites, correlating with repression of a specific set of target genes. Repressed genes encode proteins involved in cell adhesion, migration and wound healing; their promoters are enriched for binding sites of the serum response (SRF) factor. Restoring SRF activity attenuates Myc-induced apoptosis in response to glutamine starvation, exposure to Trail and to DNA damage. We propose that supra-physiological levels of Myc engage Miz1 in repressive DNA binding complexes and suppress transcriptional progr 4 different experimental conditions were analyzed: MYC-ER 4-OHT treated versus MYC-ER ctr-treated (EtOH), MYC-ER V394D 4-OHT treated versus MYC-ER V394D ctr-treated; 3 biological replicates for every condition.