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.
Oncogenic Ras inhibits IRF1 to promote viral oncolysis.
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View SamplesCertain 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- 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.
Suppression of IFN-induced transcription underlies IFN defects generated by activated Ras/MEK in human cancer cells.
Cell line, Treatment, Time
View SamplesLong-lasting activation of T cells requires up-regulation of many genes, for example of transcription factors, cytoskeletal proteins and cell surface proteins encluding ion channels. An increase of ion channel density at the cell surface reflects the needs to manage increased Ca2+ influx into the activated T cell. Using oligonucleotide-based arrays we have surveyed changes in ion channel mRNA expression that occur upon T cell activation. We used Affymetrix Analysis to confirmate our data achieved by self-designed glass array analysis.
A truncation variant of the cation channel P2RX5 is upregulated during T cell activation.
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View SamplesIn this study, we used correlation analysis of the expression profiles and carcass traits to produce a list of functional candidate genes under the assumption that genes with strong correlation between their expression values and drip belong to pathways or networks relevant for the control of the trait.
Elucidating molecular networks that either affect or respond to plasma cortisol concentration in target tissues of liver and muscle.
Specimen part
View SamplesThe inverted teat defect is an inherited disorder characterised by the failure of teats to protrude from the udder surface. The number and identity of relevant genes are unknown.
Microarray analysis reveals genes and functional networks relevant to the predisposition to inverted teats in pigs.
Specimen part
View SamplesThe mammary gland development in swine begins at embryogenesis. The number and identity of relevant genes are unknown.
Gene expression analysis of mammary tissue during fetal bud formation and growth in two pig breeds--indications of prenatal initiation of postnatal phenotypic differences.
Specimen part
View SamplesAmyotrophic lateral sclerosis and primary lateral sclerosis are two syndromic variants within the motor neurone disease spectrum. Whilst primary lateral sclerosis is associated with loss of upper motor neurons and a more benign disease course up to 17yrs, amyotrophic lateral sclerosis is caused by loss of both upper and lower motor neurons and has an average disease course of 2-3 years. The majority of cases are sporadic, thereby limiting the availability of cellular models for investigating pathogenic disease mechanisms.
Gene expression signatures in motor neurone disease fibroblasts reveal dysregulation of metabolism, hypoxia-response and RNA processing functions.
Specimen part, Disease
View SamplesIn this study, we used correlation analysis of the expression profiles and carcass traits to produce a list of functional candidate genes under the assumption that genes with strong correlation between their expression values and drip belong to pathways or networks relevant for the control of the trait.
Integrating expression profiling and whole-genome association for dissection of fat traits in a porcine model.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A high protein diet during pregnancy affects hepatic gene expression of energy sensing pathways along ontogenesis in a porcine model.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Transcriptional response of skeletal muscle to a low-protein gestation diet in porcine offspring accumulates in growth- and cell cycle-regulating pathways.
Specimen part
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