Gene expression changes with inducible expression of activated ras and ras effector domain mutants
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Kathleen Kelly
PROVIDER: E-GEOD-8916 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:Administration of tamoxifen (TAM) as breast cancer adjuvant therapy is associated with a 50% reduction in breast cancer risk and an increase in endometrial cancer risk. To investigate underlying mechanisms, we documented TAM-induced gene expression changes in cultured normal human mammary epithelial cell (NHMEC) strains (numbered 5, 16 and 40) established from tissue taken at reduction mammoplasty from three different individuals. Cells exposed to 0 and 10 uM TAM for 48 hours were evaluated for survival, TAM-DNA adduct formation by TAM-DNA chemiluminescence immunoassay (CIA), and gene expression changes using DNA-oligonucleotide microarray and real time reverse transcriptase-PCR (RT-PCR). At 48 hr, cells exposed to 10 uM TAM were 78% viable, respectively, and there were no measurable TAM-DNA adducts (limit of detection [LOD] = 0.3 adducts/10^8 nucleotides). For microarray analysis, RNA was extracted from cells exposed on three occasions to 10 uM TAM and the corresponding oligonucleotide probes were labeled with fluorescent dyes and hybridized to NCI microarrays (>20,000 human genes). Expression changes of > 3-fold were considered significant, and by these criteria, thirteen genes were up-regulated and one was down-related in NHMEC strain 16, seventeen genes were up-regulated in strain 05, and eleven genes were up-regulated in strain and 40. Elements that were up-regulated in all three cell strains included several interferon-induced genes (IFITM1, IFIT1, IFNA1, MXI and GIP3), and a potassium ion channel (KCNJ1). No significant expression changes were found for genes related to estrogen or xenobiotic metabolism. RT-PCR revealed TAM-induced up-regulation of the five genes of interest, and interferon á (IFNA1), in all three NHMEC strains, with the exception of GIP3 and MX1, which were unchanged in strain 40. The magnitude of TAM-induced up-regulation ranked: strain 16 > strain 05> strain 40. The consistent induction of interferon-related genes in all three NHMEC strains suggests that, in addition to hormonal effects, TAM exposure may enhance immune response, through interferon induction, in normal breast tissue. RNA was extracted from three cell strains (NHMEC 98016, 98040 and 99005) and exposed on three separate occasions to 10 uM TAM. Comparisons were made using 16 arrays with 8 dye swaps for cell strain NHMEC 99005, 9 arrays with 4 dye swaps for NHMEC 98016, and 12 arrays with 6 dye swaps for NHMEC 98040.
2009-01-29 | E-GEOD-13476 | biostudies-arrayexpress
Project description:HGF has been reported to have both positive and negative effects on carcinogenesis. Here we show that the loss of c-Met signaling in hepatocytes enhanced rather than suppressed the early stages of chemical hepatocarcinogenesis. c-Met conditional knockout mice (c-metfl/fl, AlbCre+/-; MetLivKO) treated with N-nitrosodiethylamine (DEN) developed significantly more and bigger tumors and with a shorter latency as compared with control (wt/wt, AlbCre+/-; Cre-Ctrl) mice. Accelerated tumor development was associated with increased rate of cell proliferation and prolonged activation of epidermal growth factor receptor (EGFR) signaling. MetLivKO livers treated with DEN also displayed elevated lipid peroxidation, decreased ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG), and upregulation of superoxide dismutase 1 (Sod1) and heat shock protein 70 (Hsp70), all consistent with increased oxidative stress. Likewise, gene expression profiling performed at 3 and 5 months after DEN treatment revealed upregulation of genes associated with cell proliferation and stress responses in c-Met mutant livers. The negative effects of c-Met-deficiency were reversed by chronic oral administration of anti-oxidant N-acetylcysteine (NAC). NAC blocked the EGFR activation and reduced the DEN-initiated hepatocarcinogenesis to the levels of Cre-Ctrl mice. These results argue that intact HGF/c-Met signaling is essential for maintaining normal redox homeostasis in the liver and has tumor suppressor effect(s) during the early stages of DEN-induced hepatocarcinogenesis. Keywords: compound treatment design To address a role for c-Met in liver carcinogenesis, we employed a hepatocyte specific c-Met conditional knockout mouse model generated in our laboratory. Mice received a single intraperitoneal injection of 10 µg/g body weight of N-nitrosodiethylamine (DEN) (Sigma-Aldrich, Inc., St. Louis, MO, USA) at 14 days of age. Livers were examined at 3 and 5 months after DEN injection. Expression profiling was conducted on five animals from each genotype per time point. Total RNA pooled from five wild-type B6/129 strain mouse livers was used as universal hybridization reference. All experiments were performed in duplicates following a dye-swapping design. Arrays were scanned with a GenePix 4000A scanner (Axon Instruments Ltd., Burlingame, CA) in a way to achieve optimal signal intensity at both channels with less than 1% saturated spots. After excluding the invalid features, all arrays were normalized to the 50th percentile of the median signal intensity using the mAdb data analysis suite (http://nciarray.nci.nih.gov/). Unsupervised cluster analysis was performed with the Cluster and TreeView programs (http://rana.lbl.gov/EisenSoftware.htm). The BRB ArrayTools V3.3.0 software package (Biometric Research Branch, National Cancer Institute; http://linus.nci.nih.gov/BRB-ArrayTools.html) was used for the supervised comparison. Differentially expressed genes were selected using a univariate 2-sample t-test (P<0.001) with a random variance model (15). Functional classification of the significant genes was based on the Gene Ontology (GO) annotations (www.geneontology.org).
2008-08-09 | E-GEOD-8747 | biostudies-arrayexpress
Project description:Hepatocarcinogenesis is a multi-stage process in which precursor lesions progress into early hepatocellular carcinomas (eHCC) by sequential accumulation of multiple genetic and epigenetic alterations. To decode the molecular events during early stages of liver carcinogenesis, we performed gene expression profiling on cirrhotic (regenerative) and dysplastic nodules (DN) as well as eHCC. Although considerable heterogeneity was observed at the regenerative and dysplastic stages, clear differences were detected between DN and eHCC which included 460 differentially expressed genes. Functional analysis of the significant gene set identified the MYC oncogene as a plausible driver gene for malignant conversion of the dysplastic nodules. In addition, gene set enrichment analysis (GSEA) revealed a remarkable enrichment of MYC up-regulated gene set in eHCC versus dysplasia. Presence of the MYC signature significantly correlated with increased expression of CSN5 as well as with the higher overall transcription rate of genes located in the 8q chromosome region. Furthermore, a classifier constructed from MYC target genes could robustly discriminate eHCC from high- and low-grade dysplastic nodules. In conclusion, our study identified unique expression patterns associated with the transition of high-grade dysplastic nodules to early HCC and demonstrated that activation of the MYC transcription signature is critical for the malignant conversion of pre-neoplastic liver lesions. Samples from forty-nine nodular liver lesions including 24 regenerative (cirrhotic) nodules (CN), 3 low-grade (LGDN), 12 high-grade dysplastic nodules (HGDN) and 10 early hepatocellular carcinomas (Early HCC) were used. The Human Operon V2 oligonucleotide library containing 22K features representing expressed sequences was printed to glass arrays in the Advanced Technology Center (National Cancer Institute, Gaithersburg, MD). The aRNA probes were fragmented and hybridized to the microarray slides following the standard procedures. All samples were hybridized against a common amplified reference RNA pooled from normal liver samples. Experimental duplicates were prepared following a reverse-flour design.
2010-05-15 | E-GEOD-12443 | biostudies-arrayexpress
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2009-02-02 | E-GEOD-14089 | biostudies-arrayexpress
Project description:The activated B cell-like (ABC) subgroup of diffuse large B cell lymphoma (DLBCL) is characterized by constitutive activation of the NF-êB pathway. Here we show that the NF- êB pathway induces the expression of the cytokines IL-6 and IL-10 in ABC DLBCL cell lines, which also have high levels of total and phosphorylated STAT3 protein, suggesting autocrine signaling. Using RNA interference for STAT3, we defined a gene expression signature of IL-6 and IL-10 signaling through STAT3. Based on this signature, we constructed a molecular predictor of STAT3 signaling that defined a subset of ABC DLBCL tumors with high expression of STAT3, IL-6 and/or IL-10, and their downstream targets. Although the STAT3-high and STAT3-low subsets had equivalent expression of genes that distinguish ABC DLBCL from GCB DLBCL, STAT3-high ABC DLBCLs had higher expression of signatures that reflected NF-kB activity, proliferation, and glycolysis. A smallmolecule inhibitor of JAK signaling, which blocked STAT3 signature expression, was toxic only for ABC DLBCL lines, and synergized with an inhibitor of NF-kB signaling. These findings suggest that the biological interplay between the STAT3 and NF-kB pathways may be exploited for the treatments of a subset of ABC DLBCLs. Activated B cell-like (ABC) subgroup of diffuse large B cell lymphoma (DLBCL) cell lines were used as model systems to study the cytokine pathways in these cells. We expressed inducible IkB super-repressor for 1 to 24 hours to identify NF-kB target genes in OCI-Ly3 and OCI-Ly10 cells for a total of 13 arrays with replicates of each time point. We treated OCI-Ly3 cells with IL-10 for 1 to 96 hours for a total of 10 arrays with replicates of each time point. We treated OCI-Ly10 cells with IL-6 for 30 minutes to 24 hours for a total of 8 arrays with replicates of each time point. OCI-Ly10 cells transfected with no siRNA versus STAT3-siRNA for 8, 24, or 48 hours for a total of 5 arrays with replicates for 24 and 48 hours. We treated OCI-Ly10 cells with JAK inhibitor I for 3 and 6 hours for a total of 4 arrays with replicates of each time point.
2010-05-27 | E-GEOD-10009 | biostudies-arrayexpress
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2009-06-01 | E-GEOD-11902 | biostudies-arrayexpress
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2010-05-25 | E-GEOD-10789 | biostudies-arrayexpress
Project description:To understand the mechanism of action of the RelE family of toxins on metabolism of Mycobacterium tuberculosis. To this effect, toxin expression was induced under control of a tetracycline regulatable promoter and transcriptional profiles compared during overexpression of the three RelE toxin family members. Profiles were also compared to previously published profiles of drugs of known mechanism of action against this organism. For the design, RNA isolated from cells where toxin expression was induced with anhydrotetracycline was converted to Cy5-labeled cDNA whereas RNA derived from cells in which toxin expression was not induced (treated with ethanol solvent only) was converted to Cy3-labeled cDNA. Time points were taken for each overexpression condition. Treatments were performed indepedently a minimum of two times to give independent biological replicates.
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2010-04-01 | E-GEOD-11247 | biostudies-arrayexpress