Hierarchical regulation in a KRAS pathway-dependent transcriptional network revealed by a reverse-engineering approach
Ontology highlight
ABSTRACT:
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE38614 | GEO | 2012/08/01
SECONDARY ACCESSION(S): PRJNA168213
REPOSITORIES: GEO
Similar Datasets
Project description:This SuperSeries is composed of the following subset Series: GSE38584: Hierarchical regulation in a KRAS pathway-dependent transcriptional network revealed by a reverse-engineering approach (7TF and control) GSE38585: Hierarchical regulation in a KRAS pathway-dependent transcriptional network revealed by a reverse-engineering approach (RAS-ROSE and ROSE with siRNA) Refer to individual Series
2012-07-31 | E-GEOD-38614 | biostudies-arrayexpress
Project description:Mutations in RAS proteins occur in 30% of human tumours and have a high relevance in tumor progression. Despite the importance of the underlying genetic network that governs the effects of oncogenic RAS, it is still poorly understood. We developed and applied a reverse-engineering approach in order to reconstruct the network structure of the signaling and gene-regulatory network downstream of RAS from perturbation experiments. We performed microarray, RT-PCR and Western Blot analysis to detect mRNA and protein levels of cytoplasmatic and nuclear targets downstream of RAS after systematic perturbation of the signaling pathways and knock-down of selected transcription factors in KRAS-transformed ovarian surface epithelium cell lines. The reconstructed model shows that the investigated components are connected through a complex network. The transcription factors decomposed into two hierarchically arranged groups. While knock-down of all investigated transcription factors showed a partial reversion of the malignant phenotype, different growth assays show that these two groups of transcription factors control different functions in the malignant anchorage-independent growth and cell cycle regulation of the ROSE cells. Furthermore, the model showed strong regulatory interplay of inhibitory and activating interactions between the RAS-dependent trancriptional network and cytoplasmatic signaling components. Overall the study contains 32 samples. We studied the influence of seven transcription factors (Fosl1, Gfi1, Hmga2, Junb, Klf6, Otx1, Rela) being knocked down by means of RNA interference. Two independent siRNA duplexes (N1, N2) against the same gene were used. All experiments were done with Cy3/Cy5 dye-swaps. As a negative control, we used scrambled siRNAs. Off-target effect was estimated by comparison of the scrambled siRNA treatment and an unterated cell line ROSEA 25.
2011-03-01 | E-GEOD-24668 | biostudies-arrayexpress
Project description:RAS mutations are highly relevant for progression and therapy response of human tumours, but the genetic network that ultimately executes the oncogenic effects is poorly understood. Here we used a reverse-engineering approach in an ovarian cancer model to reconstruct KRAS oncogene-dependent cytoplasmic and transcriptional networks from perturbation experiments based on gene silencing and pathway inhibitor treatments. We measured mRNA and protein levels in manipulated cells by microarray, RT-PCR and Western Blot analysis, respectively. The reconstructed model revealed complex interactions among the transcriptional and cytoplasmic components, some of which were confirmed by double pertubation experiments. Interestingly, the transcription factors decomposed into two hierarchically arranged groups. To validate the model predictions we analysed growth parameters and transcriptional deregulation in the KRAS-transformed epithelial cells. As predicted by the model, we found two functional groups among the selected transcription factors. The experiments thus confirmed the predicted hierarchical transcription factor regulation and showed that the hierarchy manifests itself in downstream gene expression patterns and phenotype. RAS-ROSE cells were treated with siRNA against 7 transcription factors or controls,
2012-07-31 | E-GEOD-38584 | biostudies-arrayexpress
Project description:Mutations in RAS proteins occur in 30% of human tumours and have a high relevance in tumor progression. Despite the importance of the underlying genetic network that governs the effects of oncogenic RAS, it is still poorly understood. We developed and applied a reverse-engineering approach in order to reconstruct the network structure of the signaling and gene-regulatory network downstream of RAS from perturbation experiments. We performed microarray, RT-PCR and Western Blot analysis to detect mRNA and protein levels of cytoplasmatic and nuclear targets downstream of RAS after systematic perturbation of the signaling pathways and knock-down of selected transcription factors in KRAS-transformed ovarian surface epithelium cell lines. The reconstructed model shows that the investigated components are connected through a complex network. The transcription factors decomposed into two hierarchically arranged groups. While knock-down of all investigated transcription factors showed a partial reversion of the malignant phenotype, different growth assays show that these two groups of transcription factors control different functions in the malignant anchorage-independent growth and cell cycle regulation of the ROSE cells. Furthermore, the model showed strong regulatory interplay of inhibitory and activating interactions between the RAS-dependent trancriptional network and cytoplasmatic signaling components.
2011-03-01 | GSE24668 | GEO
Project description:RAS mutations are highly relevant for progression and therapy response of human tumours, but the genetic network that ultimately executes the oncogenic effects is poorly understood. Here we used a reverse-engineering approach in an ovarian cancer model to reconstruct KRAS oncogene-dependent cytoplasmic and transcriptional networks from perturbation experiments based on gene silencing and pathway inhibitor treatments. We measured mRNA and protein levels in manipulated cells by microarray, RT-PCR and Western Blot analysis, respectively. The reconstructed model revealed complex interactions among the transcriptional and cytoplasmic components, some of which were confirmed by double pertubation experiments. Interestingly, the transcription factors decomposed into two hierarchically arranged groups. To validate the model predictions we analysed growth parameters and transcriptional deregulation in the KRAS-transformed epithelial cells. As predicted by the model, we found two functional groups among the selected transcription factors. The experiments thus confirmed the predicted hierarchical transcription factor regulation and showed that the hierarchy manifests itself in downstream gene expression patterns and phenotype.
2012-08-01 | GSE38584 | GEO
Project description:RAS mutations are highly relevant for progression and therapy response of human tumours, but the genetic network that ultimately executes the oncogenic effects is poorly understood. Here we used a reverse-engineering approach in an ovarian cancer model to reconstruct KRAS oncogene-dependent cytoplasmic and transcriptional networks from perturbation experiments based on gene silencing and pathway inhibitor treatments. We measured mRNA and protein levels in manipulated cells by microarray, RT-PCR and Western Blot analysis, respectively. The reconstructed model revealed complex interactions among the transcriptional and cytoplasmic components, some of which were confirmed by double pertubation experiments. Interestingly, the transcription factors decomposed into two hierarchically arranged groups. To validate the model predictions we analysed growth parameters and transcriptional deregulation in the KRAS-transformed epithelial cells. As predicted by the model, we found two functional groups among the selected transcription factors. The experiments thus confirmed the predicted hierarchical transcription factor regulation and showed that the hierarchy manifests itself in downstream gene expression patterns and phenotype. RAS-ROSE cells and ROSE cells treated with Scrambled siRNA
2012-07-31 | E-GEOD-38585 | biostudies-arrayexpress
Project description:RAS mutations are highly relevant for progression and therapy response of human tumours, but the genetic network that ultimately executes the oncogenic effects is poorly understood. Here we used a reverse-engineering approach in an ovarian cancer model to reconstruct KRAS oncogene-dependent cytoplasmic and transcriptional networks from perturbation experiments based on gene silencing and pathway inhibitor treatments. We measured mRNA and protein levels in manipulated cells by microarray, RT-PCR and Western Blot analysis, respectively. The reconstructed model revealed complex interactions among the transcriptional and cytoplasmic components, some of which were confirmed by double pertubation experiments. Interestingly, the transcription factors decomposed into two hierarchically arranged groups. To validate the model predictions we analysed growth parameters and transcriptional deregulation in the KRAS-transformed epithelial cells. As predicted by the model, we found two functional groups among the selected transcription factors. The experiments thus confirmed the predicted hierarchical transcription factor regulation and showed that the hierarchy manifests itself in downstream gene expression patterns and phenotype.
2012-08-01 | GSE38585 | GEO
Project description:RAS mutations are highly relevant for progression and therapy response of human tumours, but the genetic network that ultimately executes the oncogenic effects is poorly understood. Here, we used a reverse-engineering approach in an ovarian cancer model to reconstruct KRAS oncogene-dependent cytoplasmic and transcriptional networks from perturbation experiments based on gene silencing and pathway inhibitor treatments. We measured mRNA and protein levels in manipulated cells by microarray, RT-PCR and western blot analysis, respectively. The reconstructed model revealed complex interactions among the transcriptional and cytoplasmic components, some of which were confirmed by double pertubation experiments. Interestingly, the transcription factors decomposed into two hierarchically arranged groups. To validate the model predictions, we analysed growth parameters and transcriptional deregulation in the KRAS-transformed epithelial cells. As predicted by the model, we found two functional groups among the selected transcription factors. The experiments thus confirmed the predicted hierarchical transcription factor regulation and showed that the hierarchy manifests itself in downstream gene expression patterns and phenotype.
| S-EPMC3421447 | biostudies-literature
Project description:BackgroundUncovering complex network structures from a biological system is one of the main topic in system biology. The network structures can be inferred by the dynamical Bayesian network or Granger causality, but neither techniques have seriously taken into account the impact of environmental inputs.ResultsWith considerations of natural rhythmic dynamics of biological data, we propose a system biology approach to reveal the impact of environmental inputs on network structures. We first represent the environmental inputs by a harmonic oscillator and combine them with Granger causality to identify environmental inputs and then uncover the causal network structures. We also generalize it to multiple harmonic oscillators to represent various exogenous influences. This system approach is extensively tested with toy models and successfully applied to a real biological network of microarray data of the flowering genes of the model plant Arabidopsis Thaliana. The aim is to identify those genes that are directly affected by the presence of the sunlight and uncover the interactive network structures associating with flowering metabolism.ConclusionWe demonstrate that environmental inputs are crucial for correctly inferring network structures. Harmonic causal method is proved to be a powerful technique to detect environment inputs and uncover network structures, especially when the biological data exhibit periodic oscillations.
| S-EPMC2799448 | biostudies-literature
Project description:KRAS is a GTPase involved in the proliferation signaling of several growth factors. The KRAS gene is GC-rich, containing regions with known and putative G-quadruplex (G4) forming regions. Within the middle of the G-rich proximal promoter, stabilization of the physiologically active G4mid structure downregulates transcription of KRAS; the function and formation of other G4s within the gene are unknown. Herein we identify three putative G4-forming sequences (G4FS) within the KRAS gene, explore their G4 formation, and develop oligonucleotides targeting these three regions and the G4mid forming sequence. We tested Polypurine Reverse Hoogsteen hairpins (PPRHs) for their effects on KRAS regulation via enhancing G4 formation or displacing G-rich DNA strands, downregulating KRAS transcription and mediating an anti-proliferative effect. Five PPRH were designed, two against the KRAS promoter G4mid and three others against putative G4FS in the distal promoter, intron 1 and exon 5. PPRH binding was confirmed by gel electrophoresis. The effect on KRAS transcription was examined by luciferase, FRET Melt2, qRT-PCR. Cytotoxicity was evaluated in pancreatic and ovarian cancer cells. PPRHs decreased activity of a luciferase construct driven by the KRAS promoter. PPRH selectively suppressed proliferation in KRAS dependent cancer cells. PPRH demonstrated synergistic activity with a KRAS promoter selective G4-stabilizing compound, NSC 317605, in KRAS-dependent pancreatic cells. PPRHs selectively stabilize G4 formation within the KRAS mid promoter region and represent an innovative approach to both G4-stabilization and to KRAS modulation with potential for development into novel therapeutics.
| S-EPMC8876201 | biostudies-literature