Transcription profiling of human Ecr293 cells transfected with ponasterone A to identify ETS-domain transcription factor Elk-1 target genes
ABSTRACT: ETS-domain transcription factor Elk-1 target genes identified using an inducible dominant-negative expression system. Here, we use a stably-transfected EcR293 cell line containing a ponasterone A
ETS-domain transcription factors play important roles in controlling gene expression in a variety of different contexts; however, these proteins bind to very similar sites and it is unclear how in vivo specificity is achieved. In silico analysis is unlikely to reveal specific targets for individual family members and direct experimental approaches are therefore required. Here, we take advantage of an inducible dominant-negative expression system to identify a group of novel target genes for the ...[more]
Project description:Hepatitis C virus (HCV) chronically infects 170 million people worldwide and is a leading cause of liver-related mortality due to hepatocellular carcinoma and cirrhosis1. Standard-of-care treatment is shifting from interferon-alpha (IFNα)-based to IFNα-free directly acting antiviral (DAA) regimens, which demonstrate improved efficacy and tolerability in clinical trials2,3. Virologic relapse after completion of DAA therapy is a common cause of treatment failure, although mechanisms are unclear2,3. We conducted a clinical trial using the DAA sofosbuvir with ribavirin (SOF/RBV)4, and report here detailed mRNA expression analysis of pre- and end-of-treatment (EOT) liver biopsies and blood samples. On-treatment viral clearance was accompanied by rapid down-regulation of interferon-stimulated genes (ISGs) in liver and blood. Analysis of paired liver biopsies from patients who achieved a sustained virologic response (SVR) revealed that viral clearance was accompanied by decreased expression of ISGs, IFNG, and IFNLs, but increased expression of IFNA2. Patients who achieved SVR had higher expression of a hepatic type-I interferon gene signature in unpaired EOT liver biopsies than patients who later relapsed. Together, these results support a model whereby restoration of type-I intrahepatic interferon signaling at the EOT is associated with sustained hepatic HCV suppression and prevention of relapse upon withdrawal of SOF/RBV. Sustained Virologic Response for Chronic Hepatitis C Patients Treated with Sofosbuvir and Ribavirin
Project description:Ablation of ERRalpha significantly delays ERBB2-induced mammary tumorigenesis and ERRalpha regulates genes of the ERBB2 amplicon. To further investigate the relationship between ERRalpha activity and RTK signaling, we depleted ERRalpha in SKBr3 cells upon serum starvation, EGF treatment or heregulin treatment. Inhibition of ERBB2 signaling using the RTK inhibitor lapatinib impacts on ERRalpha stability. Since we have shown that the development of lapatinib-resistance restaures the expression of ERRalpha in breast cancer cells, we performed depletion of ERRalpha in SKBr3 cells that have developped resistance to lapatinib treatment in order to identify a potential reprogramming of ERRa transcriptional activity associated to lapatinib resistance, For the study of growth factor effec on ERRalpha activity, total RNA was obtained from human SKBr3 breast cancer cells cultured in DMEM deprived of FBS (starved) for 24 hours and treated with PBS, EGF (100uM) or Heregulin (100uM) for an additional 24h. Cells were transfected with siRNA against ERRalpha or with siControl for 60 hours prior to harvesting. For the effect of ERRalpha in lapatinib resistance cells, parental SKBr3 cells (pSKBr3) and Lapatinib-resistant cells (LRSKBr3, maintained in 2uM lapatinib) were transfected with siControl (siC) or siERRalpha for 60 hours prior to harvesting and RNA extraction
Project description:The human cytomegalovirus (HCMV) encodes the chemokine receptor US28 that exhibits constitutive activity. NIH-3T3 cells stably transfected with US28 present a pro-angiogenic and transformed phenotype both in vitro and in vivo. We used gene expression profiling to determine how US28 constitutive activity modulates expression of genes compared to mock-transfected cells. Experiment Overall Design: We isolated RNA from two different clonal stable cell lines of NIH-3T3 cells transfected either either mock or US28-WT and analysed these 4 RNA samples using Affymetrix mouse genome arrays.
Project description:Expression profiling was done of exposure to phorbol myristate acetate -PMA and FOXK2 depletion by siRNA transfection. This was done on the human osteosarcoma U2OS cell line which stably expresses FOXK2. PMA is an inducer of AP1 activity.
Project description:Ablation of ERRalpha significantly delays ERBB2-induced mammary tumorigenesis and ERRalpha regulates genes of the ERBB2 amplicon. To further investigate the relationship between ERRalpha activity and RTK signaling, we mapped ERRalpha binding sites in SKBr3 cells upon EGF treatment or heregulin treatment. Inhibition of ERBB2 signaling using the RTK inhibitor lapatinib impacts on ERRalpha stability, while cells resistant to lapatinib treatment exhibit restored ERRalpha expression. We therefore mapped ERRalpha binding sites in parental (sensitive) cells (pSKBr3) as well as in lapatinib-resistant cells (LRSKBr3). ChIP-Seq analysis of ERRalpha binding profile in SKBr3 or BT-474 breast cancer cells.
Project description:ELK1 is a well-known target of the ERK branch (EGF-responsive) of the MAP kinase pathway. This transcription profiling experiment studied the effects of ELK1 depletion by siRNA and subsequent EGF stimulation.
Project description:Approximately 50% of prostate cancers have chromosomal translocations resulting in the over-expression one of four ETS family transcription factors. However, it is not known why these four four family members are selected for oncogenic roles, while other ETS proteins are not. We found that the four oncogenic ETS family members have a specific role in prostate cell migration. Using chromatin immunoprecipitation coupled with next-generation sequencing, this specific biological function was matched to a specific set of genomic targets highlighted by the presence of an AP-1 binding site. ETS/AP-1 binding sites are prototypical Ras-responsive elements, but oncogenic ETS proteins could activate a Ras/MAPK transcriptional program in the absence of MAPK activation. These findings indicate that the specific function of ETS proteins over-expressed in prostate cancer is the activation of a Ras/MAPK gene expression program in the absence of signaling pathway mutations. 16 samples were analyzed, comprised of four replicates each of four different biological conditions. RNA from U0126 treated RWPE-1 empty vector cell RNA serves as a control for each experiment. Cell lines have retroviral expression constructs expressing either empty vector, Flag-ERG, or Flag-ETV1.
Project description:The endoplasmic reticulum (ER) is the site of secretory lipoprotein production and de novo cholesterol synthesis, yet little is known about how these activities are coordinated with each other, or with the activity of the COPII machinery, which transports ER cargo to the Golgi. The Sar1B component of this machinery is mutated in Chylomicron Retention Disorder, establishing that this Sar1 isoform secures delivery of dietary lipids into the circulation. We used microarrays to investigate the effect of overexpression of Sar1 isoforms and a constitutively active mutant form of Sar1B, Sar1B:H79G, on global gene expression in rat hepatoma cell line, McArdle RH7777 and identified a strong down-regulation of cholesterol biosynthetic gene mRNA expression in the Sar1B:H79G-, but not the wild-type Sar1A- or Sar1B-overexpressing cell lines. RNA was extracted from cell cultures of control McArdle RH7777, and transgenic lines overexpressing human Sar1-isoforms: one for Sar1A, two for Sar1B and two expressing a constitutively active mutant form of Sar1B, Sar1B:H79G, that cannot complete GTP hydrolysis, and hybridized on Affymetrix GeneChip Rat Genome 230 2.0 arrays.