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Characterization of a P-REX1 gene signature in breast cancer cells

ABSTRACT: The Rac nucleotide Exchange Factor (Rac-GEF) P-Rex1 is highly expressed in breast cancer, specifically in the luminal subtype, and is an essential mediator of actin cytoskeleton reorganization and cell migratory responses induced by ErbB and other tyrosine-kinase receptors. Heregulin, a growth factor highly expressed in mammary tumors, causes the activation of P-Rex1 and Rac1 in breast cancer cells via ErbB3, leading to a motile response. Since there is limited information about P-Rex1 downstream effectors, we carried out a microarray analysis to identify genes regulated by P-Rex1 in the context of HRG stimulation. In T-47D breast cancer cells, HRG treatment caused major changes in gene expression, including genes associated with motility, adhesion, invasiveness and metastasis. Silencing P-Rex1 expression from T-47D cells using RNAi altered the induction and repression of a subset of HRG-regulated genes, among them genes associated with extracellular matrix organization, migration, and chemotaxis. HRG induction of MMP10, a gene encoding for metalloproteinase-10, was found to be highly sensitive both to P-Rex1 depletion as well as inhibition of Rac1 function by the GTPase Activating Protein (GAP) 2-chimaerin, suggesting the dependence of the P-Rex1/Rac1 pathway for the induction of genes critical for breast cancer invasiveness. Notably, there is a significant association in the expression of P-Rex1 and MMP10 in human luminal breast cancer, and their co-expression is indicative of poor prognosis.

ORGANISM(S): Homo sapiens

PROVIDER: GSE77974 | GEO | 2016/09/07

SECONDARY ACCESSION(S): PRJNA312230

REPOSITORIES: GEO

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Characterization of a P-REX1 gene signature in breast cancer cells

Project description:The Rac nucleotide Exchange Factor (Rac-GEF) P-Rex1 is highly expressed in breast cancer, specifically in the luminal subtype, and is an essential mediator of actin cytoskeleton reorganization and cell migratory responses induced by ErbB and other tyrosine-kinase receptors. Heregulin, a growth factor highly expressed in mammary tumors, causes the activation of P-Rex1 and Rac1 in breast cancer cells via ErbB3, leading to a motile response. Since there is limited information about P-Rex1 downstream effectors, we carried out a microarray analysis to identify genes regulated by P-Rex1 in the context of HRG stimulation. In T-47D breast cancer cells, HRG treatment caused major changes in gene expression, including genes associated with motility, adhesion, invasiveness and metastasis. Silencing P-Rex1 expression from T-47D cells using RNAi altered the induction and repression of a subset of HRG-regulated genes, among them genes associated with extracellular matrix organization, migration, and chemotaxis. HRG induction of MMP10, a gene encoding for metalloproteinase-10, was found to be highly sensitive both to P-Rex1 depletion as well as inhibition of Rac1 function by the GTPase Activating Protein (GAP) ï¢2-chimaerin, suggesting the dependence of the P-Rex1/Rac1 pathway for the induction of genes critical for breast cancer invasiveness. Notably, there is a significant association in the expression of P-Rex1 and MMP10 in human luminal breast cancer, and their co-expression is indicative of poor prognosis. T-47D cells were serum starved and then stimulated with HRG (20 ng/ml) or vehicle (PBS) for 6 h in 60-mm plates. Three biological replicates for each experimental condition were used. For the analysis of P-Rex1-regulated genes, T-47D parental, NTC, P-Rex1#1 and P-Rex1#2 cells, with and without HRG treatment, were used (24 samples)

2016-09-07 | E-GEOD-77974 | biostudies-arrayexpress

The pseudokinase NRBP1 activates Rac/Cdc42 via P-Rex1 to drive oncogenic signalling in triple negative breast cancer

Project description:In an effort to identify oncogenic protein kinase drivers in triple negative breast cancer (TNBC), we undertook mass spectrometry (MS)-based proteomic profiling across a large panel of TNBC cell lines. This revealed marked variation in expression of the multidomain pseudokinase Nuclear Receptor Binding Protein 1 (NRBP1). Interrogation of publicly-available data determined that NRBP1 gene expression is higher in TNBC than in luminal breast cancers and positively associates with poor prognosis in TNBC patients. Gain and loss of function experiments characterized NRBP1 as a positive regulator of TNBC cell migration and invasion. In addition, NRBP1 knockdown reduced colony formation in vitro and moreover, markedly impaired growth of TNBC orthotopic xenografts as well as lung colonization in an experimental metastasis model. To interrogate the signalling mechanism of NRBP1, we applied BioID/MS profiling, identifying P-Rex1, a guanine nucleotide exchange factor for Rac1 and Cdc42, as a NRBP1 binding partner. Importantly, NRBP1 overexpression enhanced levels of GTP-bound Rac1 and Cdc42 in a P-Rex1-dependent manner, while NRBP1 knockdown reduced their activation. In addition, NRBP1 associated with P-Rex1, Rac1 and Cdc42, suggesting a scaffolding function for this pseudokinase. NRBP1-mediated promotion of cell migration and invasion was P-Rex1-dependent, while constitutively-active Cdc42 wholly/or partially rescued the effect of NRBP1 knockdown on cell migration/invasion and colony formation, respectively. Generation of reactive oxygen species via a NRBP1/P-Rex1 pathway was implicated in these oncogenic roles of NRBP1. Overall, these findings define a new function for NRBP1 and a novel oncogenic signalling pathway in TNBC that may be amenable to therapeutic intervention.

2023-05-05 | PXD032168 | Pride

The Rho Exchange Factors Vav2 and Vav3 Control a Lung Metastasis–Specific Transcriptional Program in Breast Cancer Cells

Project description:The guanosine triphosphatases of the Rho and Rac subfamilies regulate protumorigenic pathways and are activated by guanine nucleotide exchange factors (Rho GEFs), which could be potential targets for anticancer therapies. We report that two Rho GEFs, Vav2 and Vav3, play synergistic roles in breast cancer by sustaining tumor growth, neoangiogenesis, and many of the steps involved in lung-specific metastasis. The involvement of Vav proteins in these processes did not correlate with Rac1 and RhoA activity or cell migration, implying the presence of additional biological programs. Microarray analyses revealed that Vav2 and Vav3 controlled a vast transcriptional program in breast cancer cells through mechanisms that were shared between the two proteins, isoform-specific or synergistic. Furthermore, the abundance of Vav regulated transcripts was modulated by Rac1-dependent and Rac1-independent pathways. This transcriptome encoded therapeutically targetable proteins that played non redundant roles in primary tumorigenesis and lung-specific metastasis, such as integrin-linked kinase (Ilk), the transforming growth factor–b family ligand inhibin bA, cyclooxygenase-2, and the epithelial cell adhesion molecule Tacstd2. It also contained gene signatures that predicted disease outcome in breast cancer patients. These results identify possible targets for treating breast cancer and lung metastases and provide a potential diagnostic tool for clinical use.

2012-10-03 | GSE33348 | GEO

Gene expression profiling in T-47D breast cancer cells following inducible expression of estrogen receptor beta

Project description:T-47D breast cancer cells were stably transfected with a tet-off inducible construct encoding estrogen receptor beta. Microarray experiments were carried out at multiple time points 1-30 hours following treatment with estradiol and under induction and non-induction conditions. Keywords: Inducible expression of ERbeta

2007-06-01 | GSE7206 | GEO

Roles of Cdc42 and Rac in Bergmann glia during cerebellar corticogenesis (WT_primary_astrocyte)

Project description:Bergmann glia (BG) are important in the inward type of radial migration of cerebellar granule neurons (CGNs). However, details regarding the functions of Cdc42 and Rac in BG for radial migration of CGN are unknown. To examine the roles of Cdc42 and Rac in BG during cerebellar corticogenesis, mice with a single deletion of Cdc42 or Rac1 and those with double deletions of Cdc42 and Rac1 under control of the glial fibrillary acidic protein (GFAP) promoter: GFAP-Cre;Cdc42flox/flox (Cdc42-KO), GFAP–Cre;Rac1flox/flox (Rac1-KO), and GFAP-Cre;Cdc42 flox/flox;Rac1flox/flox (Cdc42/Rac1-DKO) mice, were generated. Both Cdc42-KO and Rac1-KO mice, but more obviously Cdc42-KO mice, had disturbed alignment of BG in the Purkinje cell layer (PCL). We found that Cdc42-KO, but not Rac1-KO, induced impaired radial migration of CGNs in the late phase of radial migration, leading to retention of CGNs in the inferior half of the molecular layer (ML). Cdc42-KO, but not Rac1-KO, mice also showed aberrantly aligned Purkinje cells (PCs). These phenotypes were exacerbated in Cdc42/Rac1-DKO mice. Alignment of BG radial fibers in the ML and BG endfeet at the pial surface of the cerebellum evaluated by GFAP staining was disturbed and weak in Cdc42/Rac1-DKO mice, respectively. Our data indicate that that Cdc42 and Rac, but predominantly Cdc42, in BG play important roles during the late phase of radial migration of CGNs. We also report here that Cdc42 is involved in gliophilic migration of CGNs, in contrast to Rac, which is more closely connected to regulating neurophilic migration.

2018-01-01 | GSE106141 | GEO

Roles of Cdc42 and Rac in Bergmann glia during cerebellar corticogenesis (U87_CDC42RAC1-DKD)

2018-01-01 | GSE106142 | GEO

Bistability in the Rac1, PAK and RhoA signalling network is a feature of cell motility.

Project description:Dynamic interactions between RhoA and Rac1, members of the Rho small GTPase family, play a vital role in the control of cell migration. Using predictive mathematical modelling and experimental validation in MDA-MB-231 mesenchymal breast cancer cells, we show that Rac1 and RhoA interactions via the PAK-family kinases can produce bistable, switch-like responses to a graded PAK inhibition. Using a small chemical inhibitor of PAK we confirm the model conjecture demonstrating that cellular RhoA and Rac activation levels respond in a bistable manner to PAK inhibition where for a given inhibition level these levels are high or low depending on the history of the system. Consequently, we show that downstream signalling, actin dynamics and cell migration also behave in a bistable fashion, displaying abrupt switches and hysteresis in response to PAK inhibition. In summary, our results demonstrate that PAK is a critical component in the Rac1-RhoA inhibitory crosstalk that mediates bistable GTPase activity and cell migration switches.

2016-12-23 | PXD003213 | Pride

Transcription profiling of human MCF7 cells treated with ErbB receptor ligands EGF and heregulin at multiple doses and sampled at multiple time points reveals signal transduction pathways devotedly convey quantitative properties of the dose-dependent activation of ErbB receptor to early transcription

Project description:ErbB receptor ligands, epidermal growth factor (EGF) and heregulin (HRG), induce dose-dependent transient and sustained intracellular signaling, proliferation and differentiation of MCF-7 breast cancer cells, respectively. In an effort to delineate the ligand-specific cell determination mechanism, we investigated time-course gene expressions induced by EGF and HRG that induce distinct cellular phenotypes in MCF-7 cells. To analyze the effects of ligand dosage and time for the gene expression independently, we developed a statistical method for decomposing the expression profiles into the two effects. Our results indicated that signal transduction pathways devotedly convey quantitative properties of the dose-dependent activation of ErbB receptor to early transcription. The results also implied that moderate changes in the expression levels of numbers of genes, not the predominant regulation of a few specific genes, might cooperatively work at the early stage of the transcription for determining the cell fate. However, the EGF- and HRG-induced distinct signal durations resulted in the ligand-oriented biphasic induction of proteins after 20 min. The selected gene list and HRG-induced prolonged signaling suggested that transcriptional feedback to the intracellular signaling results in a graded to biphasic response in the cell determination process, and that each ErbB receptor is inextricably responsible for the control of amplitude and duration of cellular biochemical reactions. MCF-7 human breast cancer cells were incubated from 5min to 90min after administration of different concentrations of the growth hormones (epidermal growth factor (EGF) and heregulin (HRG)). Control was set as growth hormone non-treated cells. For each growth hormone, one control was used.

2007-11-01 | E-GEOD-6462 | biostudies-arrayexpress

Genome-wide analysis of GW3965-responsive genes in 4 different breast cancer cell lines, MCF-7, T-47D, SK-BR-3, and MDA-MB-231

Project description:Analysis of differentially expressed genes in response to the LXR agonist GW3965 in the MCF-7, T-47D, SK-BR-3, and MDA-MB-231 breast cancer cell lines. It was previously reported that GW3965 has antiproliferative effects on these 4 different breast cancer cell lines. In the present study, we additionally determine the effects of the LXR ligand on breast cancer cells and determine their mechanism of action in reducing cell proliferation. Total RNA obtained from 4 different breast cancer cell lines (MCF-7, T-47D, SK-BR-3, MDA-MB-231) grown in culture treated with ethanol (control) or GW3965 (GW-treated, experimental) for 48 hours. Triplicates were performed.

2013-07-17 | E-GEOD-34987 | biostudies-arrayexpress

HACE1 prevents lung carcinogenesis via inhibition of RAC-family GTPases

Project description:HACE1 is an E3 ubiquitin ligase with important roles in tumor biology and tissue homeostasis. Loss or mutation of HACE1 has been associated with the occurrence of a variety of neoplasms, but the underlying mechanisms have not been defined yet. Here we report that HACE1 is frequently mutated in human lung cancer. In mice, loss of Hace1 led to enhanced progression of KRasG12D-driven lung tumors. Additional ablation of the oncogenic GTPase Rac1 partially reduced progression of Hace1-/- lung tumors. RAC2, a novel ubiquitylation target of HACE1, could compensate for the absence of its homolog RAC1 in Hace1-deficient, but not in HACE1-sufficient tumors. Accordingly, ablation of both Rac1 and Rac2 fully averted the increased progression of KRasG12D-driven lung tumors in Hace1-/- mice. In lung cancer patients, increased expression of HACE1 correlated with reduced levels of RAC1 and RAC2 and prolonged survival, while elevated expression of RAC1 and RAC2 was associated with poor prognosis. This work defines HACE1 as a crucial regulator of the oncogenic activity of RAC-family GTPases in lung cancer development.

2020-04-27 | GSE149137 | GEO

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