Project description:We found a far regualtory element on Ucp1 genome locus at -12kb region which was drasticlly regulated by transcription factor Etv4.
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: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: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:The ETS family of oncogenic TFs is emerging as crucial mediators of tumorigenesis in solid tumors. New insights into the molecular mechanisms hijacked by these factors will pave the way for novel therapeutic strategies. We have previously shown that ETV4 is the preponderant ETS factor that is associated with tumor progression and a worse prognosis in NSCLC. To determine the genome-wide chromatin binding of ETV4, we performed chromatin immunoprecipitation (ChIP)-sequencing studies in A549-shETV4 cells transfected with flag-ETV4 using flag antibody. In total, 54389 ETV4 binding peaks representing 25708 genes were identified (FC > 2), and 43.71% peaks were enriched in the promoter regions. Our ChIP-seq data showed that ETV4 is enriched in many genes that related with the wnt signaling pathway, MAPK signaling pathway, cell cycle, and autophagy, etc.
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:Objective: Brown adipose tissue (BAT) is important for thermoregulation in many mammals. Uncoupling protein 1 (UCP1) is the critical regulator of thermogenesis in BAT. Here we aimed to investigate the deacetylation control of BAT and to investigate a possible functional connection between UCP1 and sirtuin 3 (SIRT3), the master mitochondrial deacetylase. Methods: We carried out physiological, molecular and proteomic analyses of BAT from wild-type and Sirt3KO mice when BAT is activated. Mice were either cold exposed for 2 days or were injected with the β3-adrenergic agonist, CL316,243 (1mg/kg; i.p.). Mutagenesis studies were conducted in a cellular model to assess the impact of acetyaltion lysine sites on UCP1 function. Cardiac punctures were collected for Proteomic analysis of Acylcarnitines. Isolated mitochondria were used for functional analysis of OXPHOS. Results: Our findings showed that SIRT3 absence in mice resulted in impaired BAT lipid use, whole body thermoregulation, and respiration in BAT mitochondria, without affecting UCP1 expression. Acetylome profiling of BAT mitochondria revealed that SIRT3 regulates acetylation status of many BAT mitochondrial proteins including UCP1 and crucial upstream proteins. Mutagenesis work in cells suggested that UCP1 activity was independent of direct SIRT3-regulated lysine acetylation. However, SIRT3 impacted BAT mitochondrial activities of acylcarnitine metabolism and specific electron transport chain complexes, CI and CII.
Project description:Uncoupling protein 1 (UCP1) is thought to be a major regulator of whole-body energy expenditure and metabolic homeostasis. However, the widely employed UCP1 loss of function model has recently been shown to have destructive effects on the entire electron transport chain of thermogenic fat. As such, the role of UCP1 in metabolic regulation in vivo remains unclear. We recently identified cysteine-253 as an allosteric site on UCP1 that elevates protein activity upon covalent modification. Here we examine the physiological importance of this site through the generation of a UCP1 cysteine-253 null mouse (UCP1 C253A), the first genetic model for selective disruption of UCP1 in vivo. UCP1 C253A mice exhibit significantly compromised thermogenic responses but display no measurable effect on fat accumulation in an obesogenic environment. Unexpectedly, instead we find that lack of cysteine-253 results in substantial immune cell infiltration and inflammatory pathology in adipose tissues of male, but not female mice. Together, our results establish the UCP1 cysteine-253 activation site as a regulator of acute thermogenesis and sex-dependent adipose tissue inflammation.
Project description:In order to understand transcription factor ETV4 and ETV5 function, we have knocked down ETV4 and ETV5 synergistically in human foetal lung tip progenitor organoids using an inducible CRISPRi system. We discovered that ETV double knockdown led to organoid cell self-renewal defects
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.