RNA expression changes in MDA-MB-231 cells following MEK inhibition
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ABSTRACT: Molecular responses to MEK inhibition in cancer cells are complex and dynamic. We performed a time-series experiment to measure global RNA expression changes following treatment with the MEK inihibor U0126 MDA-MB-231 human breast cancer cells were grown in low-serum conditions. Treatment with U0126 was initiated in the presence of EGF. RNA was harvested at multiple time points during the course of 48 hours.
Project description:We conducted a proof-of-concept experiment to explore the possibility of using gene expression-based high throughput screening (GE-HTS) to find inhibitors of a signaling cascade, using platelet derived growth factor receptor (PDGFR) signaling as the example. To define ERK/PDGFR activation signature, we performed gene expression profiling using Affymetrix U133A arrays 0.5-4 hours following PDGF stimulation, thereby identifying those genes whose expression is correlated with PDGFR activity. In order to identify the component of the gene expression signature that was attributable to ERK activation by PDGFR (as opposed to other pathways downstream of PDGFR), we also pretreated the cells will the ERK inhibitors U0126 and PD98059, and repeated the gene expression profiling studies. Experiment Overall Design: To define ERK/PDGFR activation signature, SH-SY5Y cells were grown to confluence and starved overnight in serum-free medium in order to silence any sustained effects from growth factor signaling. Prior to induction with 50ng/ml PDGF, cells were treated with pathway inhibitors 74 mM Apigenin or 50 mM U0126, or with DMSO (carrier) for 60 minutes. Total RNA was isolated 30 minutes after PDGF addition. Experiments were performed in duplicate. The RNA was processed and hybridized with Affymetrix U133A GeneChips.
Project description:Certain oncolytic viruses exploit activated Ras signalling in order to replicate in cancer cells. Constitutive activation of the Ras/MEK pathway is known to suppress the effectiveness of the interferon (IFN) antiviral response, which may contribute to Ras-dependent viral oncolysis. Here, we identified 10 human cancer cell lines (out of 16) with increased sensitivity to the anti-viral effects of IFN-α after treatment with the MEK inhibitor U0126, suggesting that the Ras/MEK pathway underlies their reduced sensitivity to IFN. To determine how Ras/MEK suppresses the IFN response in these cells, we used DNA microarrays to compare IFN-induced transcription in IFN-sensitive SKOV3 cells, moderately resistant HT1080 cells, and HT1080 cells treated with U0126. We found that 267 genes were induced by IFN in SKOV3 cells, while only 98 genes were induced in HT1080 cells at the same time point. Furthermore, the expression of a distinct subset of IFN inducible genes, that included RIGI, GBP2, IFIT2, BTN3A3, MAP2, MMP7 and STAT2, was restored or increased in HT1080 cells when the cells were co-treated with U0126 and IFN. Bioinformatic analysis of the biological processes represented by these genes revealed increased representation of genes involved in the anti-viral response, regulation of apoptosis, cell differentiation and metabolism. Furthermore, introduction of constitutively active Ras into IFN sensitive SKOV3 cells reduced their IFN sensitivity and ability to activate IFN-induced transcription. This work demonstrates for the first time that activated Ras/MEK in human cancer cells induces downregulation of a specific subset of IFN-inducible genes. HT1080 cancer cells treated for 6 hours or 12 hours with interferon-alpha (500U/ml), the MEK inhibitor U0126 (20uM) or both, triplicate biological samples (18 samples). SKOV3 cells treated with interferon-alpha (500U/ml) for 6h, triplicate biological samples (6 samples).
Project description:Analysis of the differences in phosphorylation in two ferroptosis subtypes (Hemin vs classical erastin-induced ferroptosis) in neurons, and sensitivity of these changes in phosphorylation levels to treatment with ferroptosis suppressor and MEK inhibitor U0126.
Project description:Gene Expression dynamics is important information. To know IKK- or ERK-dependent B cell receptor- or CD40-induced gene expression dynamics, we performed the time course and dose response analysis in wild type or MEK inhibitor treated or IKKbeta inactive DT40 B cells. Two replicated samples were analysed. Unstimulated cells (T0) were control. WT cells or MEK Inh. (MEK inhibitor;U0126 5mM, 30min pretreated) or IKKbetaSA (S176/181A knock-in) Cells were stimulated with 0.1, 1, 10 µg/ml of anti-IgM (M4) or 1, 3, 6 µg/ml of CD40ligand (CD40L) for 0, 15, 30, 45, 60 or 90min.
Project description:TNF-a is increased in the synovial fluid of patients with rheumatoid arthritis and osteoarthritis. TNF-a activates MEK/ERK in chondrocytes; however the overall functional relevance of MEK/ERK to TNF-a-regulated gene expression in chondrocytes is unknown. Chondrocytes were treated with TNF-a with or without the MEK1/2 inhibitor U0126 for 24 h. Microarray analysis was used to identify genes regulated by TNF-a in a MEK1/2-dependent fashion. Experiment Overall Design: Primary chondrocytes from the femoral condyles of neonatal rats were treated with DMSO (control sample), TNF-a, U0126 (selective MEK1/2 inhibitor) or TNF-a and U0126. Two biological replicates were collected for each treatment. Total RNA was collected and analyzed by Affymetrix Microarray.
Project description:Oncolytic viruses exploit common molecular changes in cancer cells, which are not present in normal cells, to target and kill cancer cells. Ras transformation and defects in type I interferon (IFN)-mediated antiviral responses are known to be the major mechanisms underlying viral oncolysis. Previously, we demonstrated that oncogenic RAS/Mitogen-activated protein kinase kinase (Ras/MEK) activation suppresses the transcription of many IFN-inducible genes in human cancer cells, suggesting that Ras transformation underlies type I IFN defects in cancer cells. Here, we investigated how Ras/MEK downregulates IFN-induced transcription. By conducting promoter deletion analysis of IFN-inducible genes, namely guanylate-binding protein 2 and IFN gamma inducible protein 47 (Ifi47), we identified the IFN regulatory factor 1 (IRF1) binding site as the promoter region responsible for the regulation of transcription by MEK. MEK inhibition promoted transcription of the IFN-inducible genes in wild type mouse embryonic fibroblasts (MEFs), but not in IRF1?/? MEFs, showing that IRF1 is involved in MEK-mediated downregulation of IFN-inducible genes. Furthermore, IRF1 protein expression was lower in RasV12 cells compared with vector control NIH3T3 cells, but was restored to equivalent levels by inhibition of MEK. Similarly, the restoration of IRF1 expression by MEK inhibition was observed in human cancer cells. IRF1 re-expression in human cancer cells caused cells to become resistant to infection by the oncolytic vesicular stomatitis virus strain. Together, this work demonstrates that Ras/MEK activation in cancer cells downregulates transcription of IFN-inducible genes by targeting IRF1 expression, resulting in increased susceptibility to viral oncolysis. RNA was isolated from RasV12 transformed NIH/3T3 cells (RasV12 cells) treated with 20?M U0126 or 500U/ml IFN-?, or left untreated, for 6 hours, triplicate biological samples (9 samples).
Project description:An inducible oncogenic cell line ZFL-?Raf1-ER was established, in which oncogenic human Raf-1(?Raf1) can be activated in zebrafish liver cells by administration of 4-hydroxytamoxifen (4HT). Transcriptional profilling of the ZFL-?Raf1-ER cells with and without administration of 4HT and/or the MEK inhibitor U0126 defined the gene signatures transcriptionally regulated by hyperactive Raf/MEK/MAPK signaling in zebrafish liver cells. The ZFL-?Raf1-ER cells were cultured in 12-well plates till confluence. Cell were starved for 4h in plain medium and susequently treated with or without 1µM 4HT and/or 30µM U0126 for 12h. Biological triplications were taken for each condition.
Project description:Refined cancer models are required to assess the burgeoning number of potential targets for cancer therapeutics within a rapid and clinically relevant context. Here we utilize tumor-associated genetic pathways to transform primary human epithelial cells from epidermis, oropharynx, esophagus, and cervix into genetically defined tumors within an entirely human 3-dimensional (3-D) tissue environment incorporating cell-populated stroma and intact basement membrane (BM). These engineered organotypic tissues recapitulated natural features of tumor progression, including epithelial invasion through the BM, a complex process critically required for biologic malignancy in 90% of human cancers. Invasion was rapid, and potentiated by stromal cells. Oncogenic signals in 3-D tissue, but not 2-D culture, resembled gene expression profiles from spontaneous human cancers. Screening well-characterized signaling pathway inhibitors in 3-D organotypic neoplasia helped distil a clinically faithful cancer gene signature. Multi-tissue 3-D human tissue cancer models may provide an efficient and relevant complement to current approaches to characterize cancer progression. Organotypic human epidermal epithium expressing LacZ, cdk4 and Hras, or cdk and Ras with U0126 mediated MEK inhibition were harvested for RNA extraction and hybridization on Affymetrix microarrays. There are 8 biologic replicates for the LacZ, and cdk4 Ras groups, and 2 biologic replicates for the U0126 treated samples.
Project description:ETS1 and RAS/ERK regulate a common gene expression program in establishing enviroment suitable for prostate cancer cell migration. mRNA profiles of luciferase knockdown (WT), ETS1 knockdown, and U0126 treated DU145 cells were generated using deep sequencing, in triplicate, using Illumina HiSeq. Knockdowns were stable shRNA expression from a lentiviral construct selected with puromycin.