Ets1 is an effector of the transforming growth factor beta (TGF-beta) signaling pathway and an antagonist of the profibrotic effects of TGF-beta
ABSTRACT Extracellular matrix (ECM) production and turnover are tightly controlled under normal physiological conditions. Ets factors regulate matrix turnover by activating transcription of several metalloproteinases (MMPs) and are frequently overexpressed in aggressive tumors and arthritis. Because of the prominent role of transforming growth factor beta (TGF-beta) in ECM synthesis, this study was undertaken to determine the possible interactions between Ets1 and the TGF-beta pathway. Experiments using adenoviral delivery of Ets1 in human fibroblasts have established that Ets1 strongly suppresses TGF-beta induction of collagen type I and other matrix-related genes and reverses TGF-beta-dependent inhibition of MMP-1. Subsequent experiments utilizing COL1A2 promoter demonstrated that Ets1 in the presence of TGF-beta signaling interferes with the stimulatory role of p300. To gain further insight into the mechanism of Ets1 inhibition of the TGF-beta signaling, the protein levels and post-translational modifications of Ets1 after TGF-beta treatment were analyzed. The level of total Ets1 protein was not affected after 24 h of TGF-beta stimulation. Moreover, TGF-beta did not affect either serine or threonine phosphorylation levels of Ets1. However, TGF-beta induced rapid and prolonged lysine acetylation of Ets1. In addition, analyses of endogenous p300.Ets1 complexes revealed that acetylated Ets1 is preferentially associated with the p300/CBP complexes. TGF-beta treatment leads to dissociation of Ets1 from the CBP/p300 complexes. Together, these findings suggest that elevated expression of Ets1 in fibroblasts fundamentally alters their responses to TGF-beta in favor of matrix degradation and away from matrix deposition as exemplified by arthritis and cancer.
SourceAvailable from: Rosalinda Guevara-Guzmán[Show abstract] [Hide abstract]
ABSTRACT: Mercado-Gómez, O., et al., Role of TGF-␤ signaling pathway on Tenascin C protein upregulation in a pilocarpine seizure model. Epilepsy Res. (2014), http://dx.doi.org/10.1016/j.eplepsyres.2014.09.019 ARTICLE IN PRESS +Model EPIRES-5232; No. of Pages 11 Epilepsy Research (2014) xxx, xxx—xxx j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / e p i l e p s y r e s Summary Seizures have been shown to upregulate the expression of numerous extracellu-lar matrix molecules. Tenascin C (TNC) is an extracellular matrix protein involved in several physiological roles and in pathological conditions. Though TNC upregulation has been described after excitotoxins injection, to date there is no research work on the signal transduction path-way(s) participating in TNC protein overproduction. The aim of this study was to evaluate the role of TGF-␤ signaling pathway on TNC upregulation. In this study, we used male rats, which were injected with saline or pilocarpine to induce status epilepticus (SE) and killed 24 h, 3 and 7 days after pilocarpine administration. For evaluating biochemical changes, we measured protein content of TNC, TGF-␤1 and phospho-Smad2/3 for localization of TNC in coronal brain hippocampus at 24 h, 3 and 7 days after pilocarpine-caused SE. We found a significant increase of TNC protein content in hippocampal homogenates after 1, 3, and 7 days of pilocarpine-caused SE, together with an enhancement of TNC immunoreactivity in several hippocampal layers and the dentate gyrus field where more dramatic changes occurred. We also observed a significant enhancement of protein content of both the TGF-␤1 and the critical downstream transduction effector phospho-Smad2/3 throughout the chronic exposure. Interestingly, animals injected with SB-431542, a TGF-␤-type I receptor inhibitor, decreased TNC content in cytosolic fraction and diminished phospho-Smad2/3 content in both cytoplasmic and nuclear fractionEpilepsy research 10/2014; 108(10). DOI:10.1016/j.eplepsyres.2014.09.019 · 2.48 Impact Factor
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ABSTRACT: The RAS/ERK pathway is commonly activated in carcinomas and promotes oncogenesis by altering transcriptional programs. However, the array of cis-regulatory elements and trans-acting factors that mediate these transcriptional changes is still unclear. Our genome-wide analysis determined that a sequence consisting of neighboring ETS and AP-1 transcription factor binding sites is enriched near cell migration genes activated by RAS/ERK signaling in epithelial cells. In vivo screening of candidate ETS proteins revealed that ETS1 is specifically required for migration of RAS/ERK activated cells. Furthermore, both migration and transcriptional activation through ETS/AP-1 required ERK phosphorylation of ETS1. Genome-wide mapping of multiple ETS proteins demonstrated that ETS1 binds specifically to enhancer ETS/AP-1 sequences. ETS1 occupancy, and its role in cell migration, was conserved in epithelial cells derived from multiple tissues, consistent with a chromatin organization common to epithelial cell lines. Genome-wide expression analysis showed that ETS1 was required for activation of RAS-regulated cell migration genes, but also identified a surprising role for ETS1 in the repression of genes such as DUSP4, DUSP6 and SPRY4 that provide negative feedback to the RAS/ERK pathway. Consistently, ETS1 was required for robust RAS/ERK pathway activation. Therefore, ETS1 has dual roles in mediating epithelial-specific RAS/ERK transcriptional functions.Nucleic Acids Research 10/2014; DOI:10.1093/nar/gku929 · 8.81 Impact Factor
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ABSTRACT: Members of the ETS transcription factor family have been implicated in several cancers, where they are often dysregulated by genomic derangement. ETS variant 1 (ETV1) is an ETS factor gene that undergoes chromosomal translocation in prostate cancers and Ewing's sarcomas, amplification in melanomas, and lineage dysregulation in gastrointestinal stromal tumors. Pharmacologic perturbation of ETV1 would be appealing in these cancers; however, oncogenic transcription factors are often deemed "undruggable" by conventional methods. Here, we used small-molecule microarray (SMM) screens to identify and characterize drug-like compounds that modulate the biological function of ETV1. We identified the 1,3,5-triazine small molecule BRD32048 as a top candidate ETV1 perturbagen. BRD32048 binds ETV1 directly, modulating both ETV1-mediated transcriptional activity and invasion of ETV1-driven cancer cells. Moreover, BRD32048 inhibits p300-dependent acetylation of ETV1, thereby promoting its degradation. These results point to a new avenue for pharmacological ETV1 inhibition and may inform a general means to discover small molecule perturbagens of transcription factor oncoproteins.Molecular Cancer Therapeutics 04/2014; 13(6). DOI:10.1158/1535-7163.MCT-13-0689 · 5.60 Impact Factor