scholarly journals Activation of a prometastatic gene expression program in hypoxic neuroblastoma cells

2009 ◽  
Vol 16 (3) ◽  
pp. 991-1004 ◽  
Author(s):  
Preamrudee Poomthavorn ◽  
Sheena H X Wong ◽  
Sandra Higgins ◽  
George A Werther ◽  
Vincenzo C Russo
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Nuclear Translocation ◽  
Gene Expression Program ◽  
Nuclear Accumulation ◽  
Adaptation To Hypoxia ◽  
Mesenchymal Transition ◽  
Expression Program

The hypoxia inducible factor-1α (HIF1α) is a key regulator of oxygen homeostasis, modulating cell survival, and growth in cells exposed to hypoxia. In this study, neuroblastoma (NB) cells SH-SY5Y and SK-N-MC were employed to determine the mechanisms regulating adaptation to hypoxia. NB cells were cultured in a serum-free medium in the presence or absence of CoCl2 (100 μM, hypoxia mimic) for up to 48 h. SH-SY5Y and SK-N-MC cell numbers were not affected by CoCl2 treatment, while mitochondrial activity was reduced by ∼50% in SH-SY5Y cells and by ∼70% in SK-N-MC cells. Intracellular accumulation of HIF1α protein was detected as early as 30 min of post-hypoxia, followed by the increase of mRNA for vascular endothelial growth factor (VEGF) and nuclear accumulation of the ID1–2 transcription factors by 4 h. In hypoxic SH-SY5Y NB cells, real-time PCR analysis showed that the genes involved in maintenance of cell–cell and cell–matrix interactions (i.e. adenomatosis polyposis coli, E-cadherin, catenin, EphB2, fibronectin-1, HTATIP2, tissue inhibitor of metalloprotease-4) were down-regulated by up to 90%, while genes involved in enhancement of metastatic behavior (integrin a7b1, hepatocyte growth factor receptor, transforming growth factor-β1, VEGF, kisspeptin, interleukin-1β) were dramatically up-regulated above 200%. These changes were all consistent with the induction of epithelial–mesenchymal transition. We have thus demonstrated that NB cell adaptation to hypoxia, in addition to the modulation of HIF1α and VEGF expression and nuclear translocation of ID1 and ID2 transcription factors, involve in the activation of a gene expression program consistent with the pro-metastatic events. These processes are probably responsible for the NB cell transition from an adherent phenotype to a highly migratory, invasive and aggressive NB cell type.

scholarly journals β-Catenin/Smad3 Interaction Regulates Transforming Growth Factor-β-Induced Epithelial to Mesenchymal Transition in the Lens

2019 ◽  
Vol 20 (9) ◽  
pp. 2078 ◽  
Author(s):  
Aftab Taiyab ◽  
Julie Holms ◽  
Judith A. West-Mays
Keyword(s):  
Growth Factor ◽  
Signaling Pathways ◽  
Epithelial To Mesenchymal Transition ◽  
Vision Loss ◽  
Transforming Growth Factor ◽  
Nuclear Translocation ◽  
Ex Vivo ◽  
Smooth Muscle Actin ◽  
Posterior Capsular Opacification ◽  
Mesenchymal Transition

Cataracts are the leading cause of blindness worldwide. Although surgery is a successful method to restore vision loss due to cataracts, post-surgical complications can occur, such as secondary cataracts, also known as posterior capsular opacification (PCO). PCO arises when lens epithelial cells (LEC) are left behind in the capsular bag following surgery and are induced to undergo epithelial to mesenchymal transition (EMT). Following EMT, LEC morphology and phenotype are altered leading to a loss of transparency and vision. Transforming growth factor (TGF)-β-induced signaling through both canonical, TGF-β/Smad, and non-canonical, β-catenin/Wnt and Rho/ROCK/MRTF-A, pathways have been shown to be involved in lens EMT, and thus PCO. However, the interactions between these signaling pathways in the lens have not been thoroughly explored. In the current study we use rat LEC explants as an ex vivo model, to examine the interplay between three TGF-β-mediated pathways using α-smooth muscle actin (α-SMA) as a molecular marker for EMT. We show that Smad3 inhibition via SIS3 prevents nuclear translocation of β-catenin and MRTF-A, and α-SMA expression, suggesting a key role of Smad3 in regulation of MRTF-A and β-catenin nuclear transport in LECs. Further, we demonstrate that inhibition of β-catenin/CBP interaction by ICG-001 decreased the amount of phosphorylated Smad3 upon TGF-β stimulation in addition to significantly decreasing the expression levels of TGF-β receptors, TBRII and TBRI. Overall, our findings demonstrate interdependence between the canonical and non-canonical TGF-β-mediated signaling pathways controlling EMT in the lens.

scholarly journals NFI-Ski Interactions Mediate Transforming Growth Factor β Modulation of Human Papillomavirus Type 16 Early Gene Expression

2004 ◽  
Vol 78 (8) ◽  
pp. 3953-3964 ◽  
Author(s):  
Amy Baldwin ◽  
Lucia Pirisi ◽  
Kim E. Creek
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Growth Factor ◽  
Binding Sites ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Early Gene ◽  
Early Gene Expression ◽  
Nuclear Extracts ◽  
E6 And E7

ABSTRACT Human papillomaviruses (HPVs) are present in virtually all cervical cancers. An important step in the development of malignant disease, including cervical cancer, involves a loss of sensitivity to transforming growth factor β (TGF-β). HPV type 16 (HPV16) early gene expression, including that of the E6 and E7 oncoprotein genes, is under the control of the upstream regulatory region (URR), and E6 and E7 expression in HPV16-immortalized human epithelial cells is inhibited at the transcriptional level by TGF-β. While the URR contains a myriad of transcription factor binding sites, including seven binding sites for nuclear factor I (NFI), the specific sequences within the URR or the transcription factors responsible for TGF-β modulation of the URR remain unknown. To identify potential transcription factors and binding sites involved in TGF-β modulation of the URR, we performed DNase I footprint analysis on the HPV16 URR using nuclear extracts from TGF-β-sensitive HPV16-immortalized human keratinocytes (HKc/HPV16) treated with and without TGF-β. Differentially protected regions were found to be located around NFI binding sites. Electrophoretic mobility shift assays, using the NFI binding sites as probes, showed decreased binding upon TGF-β treatment. This decrease in binding was not due to reduced NFI protein or NFI mRNA levels. Mutational analysis of individual and multiple NFI binding sites in the URR defined their role in TGF-β sensitivity of the promoter. Overexpression of the NFI family members in HKc/HPV16 decreased the ability of TGF-β to inhibit the URR. Since the oncoprotein Ski has been shown to interact with and increase the transcriptional activity of NFI and since cellular Ski levels are decreased by TGF-β treatment, we explored the possibility that Ski may provide a link between TGF-β signaling and NFI activity. Anti-NFI antibodies coimmunoprecipitated endogenous Ski in nuclear extracts from HKc/HPV16, confirming that NFI and Ski interact in these cells. Ski levels dramatically decreased upon TGF-β treatment of HKc/HPV16, and overexpression of Ski eliminated the ability of TGF-β to inhibit the URR. Based on these studies, we propose that TGF-β inhibition of HPV16 early gene expression is mediated by a decrease in Ski levels, which in turn dramatically reduces NFI activity.

scholarly journals Foxp transcription factors suppress a non-pulmonary gene expression program to permit proper lung development

2016 ◽  
Vol 416 (2) ◽  
pp. 338-346 ◽  
Author(s):  
Shanru Li ◽  
Michael Morley ◽  
MinMin Lu ◽  
Su Zhou ◽  
Kathleen Stewart ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Lung Development ◽  
Gene Expression Program ◽  
Expression Program

scholarly journals MEF2 (Myocyte Enhancer Factor 2) Is Essential for Endothelial Homeostasis and the Atheroprotective Gene Expression Program

2021 ◽  
Author(s):  
Yao Wei Lu ◽  
Nina Martino ◽  
Brennan D. Gerlach ◽  
John M. Lamar ◽  
Peter A. Vincent ◽  
...  
Keyword(s):  
Gene Expression ◽  
Shear Stress ◽  
Transcription Factors ◽  
Gene Expression Program ◽  
Binding Motif ◽  
Myocyte Enhancer Factor 2 ◽  
Myocyte Enhancer Factor ◽  
Anti Inflammatory ◽  
Expression Program ◽  
Enhancer Factor

Objective: Atherosclerosis predominantly forms in regions of oscillatory shear stress while regions of laminar shear stress are protected. This protection is partly through the endothelium in laminar flow regions expressing an anti-inflammatory and antithrombotic gene expression program. Several molecular pathways transmitting these distinct flow patterns to the endothelium have been defined. Our objective is to define the role of the MEF2 (myocyte enhancer factor 2) family of transcription factors in promoting an atheroprotective endothelium. Approach and Results: Here, we show through endothelial-specific deletion of the 3 MEF2 factors in the endothelium, Mef2a, -c, and -d, that MEF2 is a critical regulator of vascular homeostasis. MEF2 deficiency results in systemic inflammation, hemorrhage, thrombocytopenia, leukocytosis, and rapid lethality. Transcriptome analysis reveals that MEF2 is required for normal regulation of 3 pathways implicated in determining the flow responsiveness of the endothelium. Specifically, MEF2 is required for expression of Klf2 and Klf4, 2 partially redundant factors essential for promoting an anti-inflammatory and antithrombotic endothelium. This critical requirement results in phenotypic similarities between endothelial-specific deletions of Mef2a/c/d and Klf2/4. In addition, MEF2 regulates the expression of Notch family genes, Notch1, Dll1, and Jag1, which also promote an atheroprotective endothelium. In contrast to these atheroprotective pathways, MEF2 deficiency upregulates an atherosclerosis promoting pathway through increasing the amount of TAZ (transcriptional coactivator with PDZ-binding motif). Conclusions: Our results implicate MEF2 as a critical upstream regulator of several transcription factors responsible for gene expression programs that affect development of atherosclerosis and promote an anti-inflammatory and antithrombotic endothelium.

scholarly journals The Transcription Factor FoxK Participates with Nup98 To Regulate Antiviral Gene Expression

mBio ◽  
2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Debasis Panda ◽  
Beth Gold ◽  
Michael A. Tartell ◽  
Keiko Rausch ◽  
Sergio Casas-Tinto ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Gene Expression Program ◽  
Luciferase Reporter ◽  
Nuclear Pore ◽  
Response Element ◽  
Antiviral Genes ◽  
Expression Program ◽  
Antiviral Gene

ABSTRACT Upon infection, pathogen recognition leads to a rapidly activated gene expression program that induces antimicrobial effectors to clear the invader. We recently found that Nup98 regulates the expression of a subset of rapidly activated antiviral genes to restrict disparate RNA virus infections in Drosophila by promoting RNA polymerase occupancy at the promoters of these antiviral genes. How Nup98 specifically targets these loci was unclear; however, it is known that Nup98 participates with transcription factors to regulate developmental-gene activation. We reasoned that additional transcription factors may facilitate the Nup98-dependent expression of antiviral genes. In a genome-wide RNA interference (RNAi) screen, we identified a relatively understudied forkhead transcription factor, FoxK, as active against Sindbis virus (SINV) in Drosophila. Here we find that FoxK is active against the panel of viruses that are restricted by Nup98, including SINV and vesicular stomatitis virus (VSV). Mechanistically, we show that FoxK coordinately regulates the Nup98-dependent expression of antiviral genes. Depletion of FoxK significantly reduces Nup98-dependent induction of antiviral genes and reduces the expression of a forkhead response element-containing luciferase reporter. Together, these data show that FoxK-mediated activation of gene expression is Nup98 dependent. We extended our studies to mammalian cells and found that the mammalian ortholog FOXK1 is antiviral against two disparate RNA viruses, SINV and VSV, in human cells. Interestingly, FOXK1 also plays a role in the expression of antiviral genes in mammals: depletion of FOXK1 attenuates virus-inducible interferon-stimulated response element (ISRE) reporter expression. Overall, our results demonstrate a novel role for FOXK1 in regulating the expression of antiviral genes, from insects to humans. IMPORTANCE Innate immunity is characterized by rapid gene expression programs, from insects to mammals. Furthermore, we find that Nup98, known for its roles in the nuclear pore, plays a noncanonical role in binding the promoters and poising a subset of loci for rapid antiviral gene induction. It was unclear how Nup98 accesses these specific genes, and we here demonstrate that Nup98 cooperates with the transcription factor FoxK to regulate this gene expression program. Depletion of FoxK specifically reduces the induction of Nup98-dependent genes. Further, we find that the antiviral function of FoxK is conserved, as the human ortholog FOXK1 is also antiviral and regulates gene expression from virus-induced promoters. Although other forkhead transcription factors have been implicated in immunity, a role for FoxK in antiviral defense was previously unappreciated. Our findings reveal a conserved and novel role for FoxK in coordinating with Nup98 to promote a robust and complex antiviral transcriptional response.

Regulation of Epithelial-Mesenchymal Transition in Palatal Fusion

2009 ◽  
Vol 234 (5) ◽  
pp. 483-491 ◽  
Author(s):  
Wenli Yu ◽  
Louis-Bruno Ruest ◽  
Kathy K. H. Svoboda
Keyword(s):  
Transcription Factors ◽  
Growth Factor ◽  
Signaling Pathways ◽  
Transforming Growth Factor ◽  
Epithelial Mesenchymal Transition ◽  
Molecular Evidence ◽  
Mesenchymal Transition ◽  
Palatal Fusion

During palatal fusion, the midline epithelial seam between the palatal shelves degrades to achieve mesenchymal confluence. Morphological and molecular evidence support the theory that the epithelial-mesenchymal transition is one mechanism that regulates palatal fusion. It appears that transforming growth factor (TGF)-β signaling plays a role in palatal EMT. TGFβ3 is the main inducer in palatal fusion and activates both Smad-dependent and -independent signaling pathways, including the key EMT transcription factors, Lef1, Twist, and Snail1, in the MEE prior to the palatal EMT program. The roles and interactions among these transcription factors will be discussed.

scholarly journals STAT3 and GR cooperate to drive basal-like triple negative breast cancer gene expression and proliferation

2019 ◽  
Author(s):  
Megan E. Conway ◽  
Joy M. McDaniel ◽  
James M. Graham ◽  
Katrin P. Guillen ◽  
Patsy G. Oliver ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Transcription Factors ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Gene Expression Program ◽  
Luminal Breast Cancer ◽  
Cancer Gene ◽  
Expression Program ◽  
Breast Cancer Gene

AbstractBreast cancers can be divided into subtypes with different prognoses and treatment responses based on global gene expression differences. Luminal breast cancer gene expression and proliferation are driven by the transcription factors Estrogen Receptor α (ER), FOXA1 and GATA3. Targeting ER is the most effective therapy for treating luminal breast cancer because ER is the master regulator of the luminal gene expression program. In contrast, it is unclear which transcription factors are responsible for driving the gene expression signature that defines basal-like triple negative breast cancer, and there are no targeted therapies approved to treat this aggressive subtype of the disease. This study utilized integrated analysis of DNA methylation, chromatin accessibility, transcription factor binding, and gene expression in large collections of breast cancer cell lines and patient tumors to identify transcription factors responsible for the basal-like gene expression program. The results of this study indicate that glucocorticoid receptor (GR) and signal transducer and activator of transcription 3 (STAT3) bind to the same genomic regulatory regions that are specifically open and unmethylated in basal-like breast cancer. These transcription factors cooperate to regulate expression of hundreds of genes in the basal-like gene expression signature and these downstream genes are associated with poor prognosis in patients. Furthermore, combination treatment with small molecule drugs that inhibit both transcription factors leads to synergistic decreases in cell proliferation in cell lines and patient-derived organoid models. This study demonstrates that GR and STAT3 cooperate to regulate the basal-like breast cancer gene expression program and provides the basis for improved therapy for basal-like triple negative breast cancer through rational combination of STAT3 and GR inhibitors.

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