Project description:All extant amniotes employ a single-layered epithelium of epiblasts as a starting material for gastrulation, suggesting the necessity of the epithelial structure for three germ layer derivation. Using a human embryonic stem cell (hESC) epithelium as a model system, we found that local epithelial crowding derepresses the neuroectoderm fate by spatiotemporal inactivation of ETV4. ETV4 serves as a genetic toggle switch that links cell density to lineage fates. Mechanistically, cell crowding blocks FGF receptor endocytosis by reduced cell-extracellular matrix (ECM) interaction. Disrupted endocytosis decreases ETV4 protein stability by ERK inactivation. Mathematical modeling of epithelial crowding demonstrates that the cooperativity of integrin-ECM interaction transforms the gradient of crowdedness into bistable ETV4 transition, which ensures the switch-like function of ETV4 in lineage determination. Our results propose local cell crowding in a stem cell epithelium as a key cellular mechanism for spatiotemporal regulation of lineage fates.
Project description:ETV4 and ETV5 are FGF-activated transcription factor genes. Inactivation of Etv4 and Etv5 in the lung epithelium led to prolonged branch tip growth and delayed new branch formation. We used microarrays to detail the global programme of gene expression in embryonic day 13.5 mouse lungs and identified distinct classes of dysregulated genes affect by Etv4;5 epithelial specific knockout.
Project description:ETS-related transcription factors ETV4 and ETV5 play crucial roles for organogenesis and morphogenesis. We compared the transcriptional profiles between wild-type and ETV4 and ETV5 double knockout (ETV4/5 dKO) ES cells by an oligo DNA microarray analysis. Self-renewal capacity and pluripotency are known to be controlled by an ES cell-specific transcription factor network; therefore, we focused on transcription-associated genes. Of 1258 transcription-related genes, 47 genes were significantly downregulated and 98 genes were significantly upregulated in ETV4/5 dKO ES cells. Several genes whose expression is specific to undifferentiated ES were repressed in ETV4/5 dKO ES cells. In contrast, expression of differentiation markers was enhanced in ETV4/5 dKO ES cells.
Project description:Our in vitro binding studies support a model whereby MED25 exhibits multivalent interactions with a subset of related ETS factors, ETV1/4/5. We hypothesize that the interaction would allow for coregulation of genes by ETV1/4/5 and MED25, acting perhaps to link the ETVs to the Mediator complex. To explore this possibility, we compared the genome occupancy for FLAG-tagged MED25 and ETV4 in the prostate cancer cell line PC3, which overexpresses ETV4. We also tested for relevance of MED25 and ETV4 binding to for gene expression in PC3s. We found a high degree of overlap in the FLAG-MED25 and ETV4 ChIPs datasets consistent with our model, and also identified a subset of target genes co-dependent on Med25 and ETV4.
Project description:To determine the molecular signaling pathways responsible for ETV4 regulation of cell growth, RNA sequencing was conducted on LPC-HRas cells with or without ETV4 knockdown
Project description:Our in vitro binding studies support a model whereby MED25 exhibits multivalent interactions with a subset of related ETS factors, ETV1/4/5. We hypothesize that the interaction would allow for coregulation of genes by ETV1/4/5 and MED25, acting perhaps to link the ETVs to the Mediator complex. To explore this possibility, we compared the genome occupancy for FLAG-tagged MED25 and ETV4 in the prostate cancer cell line PC3, which overexpresses ETV4. We also tested for relevance of MED25 and ETV4 binding to for gene expression in PC3s. We found a high degree of overlap in the FLAG-MED25 and ETV4 ChIPs datasets consistent with our model, and also identified a subset of target genes co-dependent on Med25 and ETV4.
Project description:Chromosomal abnormalities that give rise to elevated expression levels of the ETS genes ETV1, ETV4, ETV5, or ERG are prevalent in prostate cancer, but the function of these transcription factors in carcinogenesis is not clear. Previous work implicates ERG, ETV1, and ETV5 as regulators of invasive growth but not transformation in cell lines. Here we show that the PC3 prostate cancer cell line provides a model system to study the over-expression of ETV4. Anchorage independent growth assays and microarray analysis indicate that high ETV4 expression is critical for the transformation phenotype of PC3 cells. However, genes up-regulated upon ETV4 over-expression were very similar to genes up-regulated by ETV1 over-expression in the RWPE-1 normal prostate cell line. Together these data indicate that the ETV4 dependent transformation phenotype observed in PC3 cells is due to the genetic background of the cell line, rather than a distinct characteristic of ETV4. Furthermore, these findings suggest that the function of ETS genes in prostate cancer may differ based on other genetic alterations in a tumor. Two sets of two color experiments. First is PC3 cells expressing one of two independent ETV4 shRNAs versus PC3 cells expressing a control shRNA (luciferase). Second is RWPE-1 cells expressing 3xFlag tagged ETV4 versus RWPE-1 cells with a control (empty) vector.
Project description:In order to propagate a solid tumor, cancer cells must adapt to and survive under various tumor microenvironment (TME) stresses, such as hypoxia or lactic acidosis. To systematically identify genes that modulate cancer cell survival under stresses, we performed genome-wide shRNA screens under hypoxia or lactic acidosis. We discovered that genetic depletion of acetyl-CoA carboxylase (ACACA or ACC1) or ATP citrate lyase (ACLY) protected cancer cells from hypoxia-induced apoptosis. Additionally, loss of ACLY or ACC1 reduced levels and activities of the oncogenic transcription factor ETV4. Silencing ETV4 also protected cells from hypoxia-induced apoptosis and led to remarkably similar transcriptional responses as with silenced ACLY or ACC1, including an anti-apoptotic program. Metabolomic analysis found that while α-ketoglutarate levels decrease under hypoxia in control cells, α-ketoglutarate is paradoxically increased by hypoxia when ACC1 or ACLY are depleted. Supplementation with α-ketoglutarate rescued the hypoxia-induced apoptosis and recapitulated the decreased expression and activity of ETV4 via an epigenetic mechanism. Therefore, ACC1 and ACLY regulate the levels of ETV4 under hypoxia via increased α-ketoglutarate. These results reveal that ACC1/ACLY- α-ketoglutarate-ETV4 is a novel means by which metabolic states regulate transcriptional output for life vs. death decisions under hypoxia. Since many lipogenic inhibitors are under investigation as cancer therapeutics, our findings suggest that the use of these inhibitors will need to be carefully considered with respect to oncogenic drivers, tumor hypoxia, progression and dormancy. More broadly, our screen provides a framework for studying additional tumor cell stress-adaption mechanisms in the future. DESIGN: H1975 lung cancer cells transduced with a scramble shRNA hairpin or two different shRNAs against ACLY, ACC1, or ETV4 under hypoxia.
Project description:Chromosomal translocations or upregulations involving ETS transcription factor are frequent events in prostate cancer pathogenesis and significantly co-occurrence with p53 or PTEN loss. Caused by the low stabilities of ETS proteins in cytosol, mouse models with aberrant expression of wild type ETS transcription factors had subtle phenotypes and only drive prostate cancer progression in the setting of Pten loss. Here we show that prostate specific aberrant expression of mutated ETV4 (V70P71D72-AAA, ETV4-AAA), which is resistence to COP1 mediated protein degradation, results in more stabilized ETV4 protein in mouse prostate. We found that ETV4-AAA mice develop marked prostatic intraepithelial neoplasia (mPin) and p53-dependent cell senescence within 2 weeks, but without tumor development when aged. Interestingly, ETV4-AAA positive cells reduce dramatically in a PTEN loss background, which means that there is no cooperation between ETV4-AAA and PTEN loss. Aberrant ETV4-AAA expression promotes progression of mPin to prostatic adenocarcinoma in a Tp53 deficiency or haploinsufficiency background. In contrast to PTEN loss induced mouse prostate cancers which loss NKX3.1 expression and resistant to castration therapy, these ETV4-AAA tumor cells well maintain AR and NKX3.1 expression and are sensitive to castration therapy.
Project description:Estrogen signaling through estrogen receptor alpha (ER) plays a major role in endometrial cancer risk and progression; however, the molecular mechanisms underlying ER’s regulatory role in endometrial cancer are poorly understood. In breast cancer cells, ER genomic binding is enabled by FOXA1 and GATA3, but the transcription factors that control ER genomic binding in endometrial cancer cells remain unknown. We previously identified ETV4 as a candidate factor controlling ER genomic binding in endometrial cancer cells and here we explore the functional importance of ETV4. Homozygous deletion of ETV4, using CRISPR/Cas9, led to greatly reduced ER binding at the majority of loci normally bound by ER. Consistent with the dramatic loss of ER binding, the gene expression response to estradiol was dampened for most genes. ETV4 contributes to estrogen signaling in two distinct ways; ETV4 loss impacts chromatin accessibility at some ER bound loci and impairs ER nuclear translocation. The diminished estrogen signaling upon ETV4 deletion led to decreased growth, particularly in 3D culture where hollow organoids were formed. Our results show that ETV4 plays a necessary role in estrogen signaling in endometrial cancer cells.