HDAC1-Smad3-mSin3Acomplex is required for Smad3-induced transcriptional inhibition of hepatocyte growth factor receptor in human lung cancers

2020 ◽  
Author(s):  
Hao-Xin Gui ◽  
Jun Peng ◽  
Ze-Ping Yang ◽  
Lu-Yao Chen ◽  
Hong Zeng ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Molecular Mechanisms ◽  
Growth Factor Receptor ◽  
Mrna Levels ◽  
Lung Cancers ◽  
Transcriptional Inhibition ◽  
Transcriptional Suppression ◽  
Transcriptional Regulatory ◽  
Regulatory Complex ◽  
Cancer Tissues

Abstract c-Met hyperactivity has been observed in numerous neoplasms. Several researchers have shown that the abnormal activation of c-Met is mainly caused by transcriptional activation. However, the molecular mechanism behind this transcriptional regulation is poorly understood. Here, we suggest that Smad3 negatively regulates the expression and activation of c-Met via a transcriptional mechanism. We explore the molecular mechanisms that underlie Smad3-induced c-Met transcription inhibition. We found in contrast to the high expression of c-Met, Smad3 showed low protein and mRNA levels. Smad3 and c-Met expression was inconsistent between lung cancer tissues and cell lines. We also found that Smad3 overexpression suppresses whereas Smad3 knockdown significantly promotes EMT and production of the angiogenic factors VEGF, CTGF and COX-2 through the ERK1/2 pathway. In addition, Smad3 overexpression decreases whereas Smad3 knockdown significantly increases protein and mRNA levels of invasion related β-catenin and FAK through the PI3K/Akt pathway. Furthermore, using the ChIP analysis method, we demonstrate that a transcriptional regulatory complex consisting of HDAC1, Smad3 and mSin3A binds to the promoter of the c-Met gene. By either silencing endogenous mSin3A expression with siRNA or by pretreating cells with a specific HDAC1 inhibitor (MS-275), Smad3-induced transcriptional suppression of c-Met could be effectively attenuated. These results demonstrate that Smad3-induced inhibition of c-Met transcription depends on of a functional transcriptional regulatory complex that includes Smad3, mSin3A and HDAC1 at the c-Met promoter. Collectively, our findings reveal a new regulatory mechanism of c-Met signaling, and suggest a potential molecular target for the development of anticancer drugs.

scholarly journals Smad3-mSin3A-HDAC1 Complex is Required for TGF-β1-Induced Transcriptional Inhibition of PPARγ in Mouse Cardiac Fibroblasts

2016 ◽  
Vol 40 (5) ◽  
pp. 908-920 ◽  
Author(s):  
Kaizheng Gong ◽  
Mingxing Chen ◽  
Rujun Li ◽  
Yanghong He ◽  
Huajiang Zhu ◽  
...  
Keyword(s):  
Promoter Activity ◽  
Molecular Mechanisms ◽  
Cardiac Fibroblasts ◽  
Luciferase Reporter ◽  
Transcriptional Inhibition ◽  
Transcriptional Regulatory ◽  
Promoter Deletion Analysis ◽  
Regulatory Complex ◽  
Pparγ Gene ◽  
Tgf Β1

Background: We have recently demonstrated that activated transforming growth factor-β (TGF-β) signaling suppresses myocardial peroxisome proliferator-activated receptor γ (PPARγ) expression in the pressure overloaded heart. In this study, we aim to further define the molecular mechanisms that underlie TGF-β-induced PPARγ transcriptional inhibition. Methods: Adult mouse cardiac fibroblasts were isolated and cultured. PPARγ promoter activity was measured by the dual-Luciferase reporter assay. Interactions between transcription factors and the target gene were identified. Results: In cultured cardiac fibroblasts transfected with a plasmid containing a human PPARγ promoter, co-transfection of Smad3 and Smad4, but not Smad2, plasmids significantly enhanced TGF-β1-induced inhibition of PPARγ promoter activity. Promoter deletion analysis and site-directed mutagenesis assays defined two Smad binding elements on the promoter of the PPARγ gene. Utilizing chromatin immunoprecipitation analysis and DNA-affinity precipitation methods, we demonstrated that the transcriptional regulatory complex consisting of Smad3, mSin3A and HDAC1 bound to the promoter of the PPARγ gene in cardiac fibroblasts in response to TGF-β1 stimulation. Either silencing endogenous mSin3A expression by Lentivirus-mediated transduction of mSin3A shRNA or pretreatment with the specific HDAC1 inhibitor MS-275 effectively attenuated TGF-β-induced transcriptional suppression of PPARγ. Conclusion: These results suggest that TGF-β1-induced inhibition of PPARγ transcription depends on formation of a functional transcriptional regulatory complex that includes Smad3, mSin3A and HDAC1 at the PPARγ promoter.

scholarly journals Adenovirus E1A specifically blocks SWI/SNF-dependent transcriptional activation.

1996 ◽  
Vol 16 (10) ◽  
pp. 5737-5743 ◽  
Author(s):  
M E Miller ◽  
B R Cairns ◽  
R S Levinson ◽  
K R Yamamoto ◽  
D A Engel ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Cellular Transformation ◽  
Transcriptional Coactivator ◽  
Gene Encoding ◽  
Adenovirus E1a ◽  
Transcriptional Regulatory ◽  
Genes Encoding ◽  
Regulatory Complex ◽  
Activation Pathways ◽  
Coactivator P300

Expression of the adenovirus E1A243 oncoprotein in Saccharomyces cerevisiae produces a slow-growth phenotype with accumulation of cells in the G1 phase of the cell cycle. This effect is due to the N-terminal and CR1 domains of E1A243, which in rodent cells are involved in triggering cellular transformation and also in binding to the cellular transcriptional coactivator p300. A genetic screen was undertaken to identify genes required for the function of E1A243 in S. cerevisiae. This screen identified SNF12, a gene encoding the 73-kDa subunit of the SWI/SNF transcriptional regulatory complex. Mutation of genes encoding known members of the SWI/SNF complex also led to loss of E1A function, suggesting that the SWI/SNF complex is a target of E1A243. Moreover, expression of E1A in wild-type cells specifically blocked transcriptional activation of the INO1 and SUC2 genes, whose activation pathways are distinct but have a common requirement for the SWI/SNF complex. These data demonstrate a specific functional interaction between E1A and the SWI/SNF complex and suggest that a similar interaction takes place in rodent and human cells.

scholarly journals DNA Recognition by the Herpes Simplex Virus Transactivator VP16: a Novel DNA-Binding Structure

2001 ◽  
Vol 21 (14) ◽  
pp. 4700-4712 ◽  
Author(s):  
Robert Babb ◽  
C. Chris Huang ◽  
Deborah J. Aufiero ◽  
Winship Herr
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Dna Binding ◽  
Transcriptional Activation ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Transcriptional Regulatory ◽  
Regulatory Complex ◽  
Simplex Virus ◽  
Carboxy Terminal

ABSTRACT Upon infection, the herpes simplex virus (HSV) transcriptional activator VP16 directs the formation of a multiprotein-DNA complex—the VP16-induced complex—with two cellular proteins, the host cell factor HCF-1 and the POU domain transcription factor Oct-1, on TAATGARAT-containing sequences found in the promoters of HSV immediate-early genes. HSV VP16 contains carboxy-terminal sequences important for transcriptional activation and a central conserved core that is important for VP16-induced complex assembly. On its own, VP16 displays little, if any, sequence-specific DNA-binding activity. We show here that, within the VP16-induced complex, however, the VP16 core has an important role in DNA binding. Mutation of basic residues on the surface of the VP16 core reveals a novel DNA-binding surface with essential residues which are conserved among VP16 orthologs. These results illuminate how, through association with DNA, VP16 is able to interpret cis-regulatory signals in the DNA to direct the assembly of a multiprotein-DNA transcriptional regulatory complex.

scholarly journals Distinct Glucocorticoid Receptor Transcriptional Regulatory Surfaces Mediate the Cytotoxic and Cytostatic Effects of Glucocorticoids

1999 ◽  
Vol 19 (7) ◽  
pp. 5036-5049 ◽  
Author(s):  
Inez Rogatsky ◽  
Adam B. Hittelman ◽  
David Pearce ◽  
Michael J. Garabedian
Keyword(s):  
Glucocorticoid Receptor ◽  
Transcriptional Activation ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Cellular Proliferation ◽  
Antiproliferative Effect ◽  
Glucocorticoid Treatment ◽  
Transcriptional Regulatory ◽  
Human Osteosarcoma Cells ◽  
Transcriptional Regulatory Mechanisms

ABSTRACT Glucocorticoids act through the glucocorticoid receptor (GR), which can function as a transcriptional activator or repressor, to elicit cytostatic and cytotoxic effects in a variety of cells. The molecular mechanisms regulating these events and the target genes affected by the activated receptor remain largely undefined. Using cultured human osteosarcoma cells as a model for the GR antiproliferative effect, we demonstrate that in U20S cells, GR activation leads to irreversible growth inhibition, apoptosis, and repression of Bcl2. This cytotoxic effect is mediated by GR’s transcriptional repression function, since transactivation-deficient mutants and ligands still bring about apoptosis and Bcl2 down-regulation. In contrast, the antiproliferative effect of GR in SAOS2 cells is reversible, does not result in apoptosis or repression of Bcl2, and is a function of the receptor’s ability to stimulate transcription. Thus, the cytotoxic versus cytostatic outcome of glucocorticoid treatment is cell context dependent. Interestingly, the cytostatic effect of glucocorticoids in SAOS2 cells involves multiple GR activation surfaces. GR mutants and ligands that disrupt individual transcriptional activation functions (activation function 1 [AF-1] and AF-2) or receptor dimerization fail to fully inhibit cellular proliferation and, remarkably, discriminate between the targets of GR’s cytostatic action, the cyclin-dependent kinase inhibitors p21Cip1 and p27Kip1. Induction of p21Cip1 is agonist dependent and requires AF-2 but not AF-1 or GR dimerization. In contrast, induction of p27Kip1 is agonist independent, does not require AF-2 or AF-1, but depends on GR dimerization. Our findings indicate that multiple GR transcriptional regulatory mechanisms that employ distinct receptor surfaces are used to evoke either the cytostatic or cytotoxic response to glucocorticoids.

scholarly journals Advanced Glycated End-Products Affect HIF-Transcriptional Activity in Renal Cells

2013 ◽  
Vol 27 (11) ◽  
pp. 1918-1933 ◽  
Author(s):  
Tzvetanka Bondeva ◽  
Juliane Heinzig ◽  
Carola Ruhe ◽  
Gunter Wolf
Keyword(s):  
Transcriptional Activation ◽  
Transcriptional Activity ◽  
Molecular Mechanisms ◽  
Mesangial Cells ◽  
Hypoxia Inducible Factor ◽  
Mrna Levels ◽  
Proximal Tubular Cells ◽  
Tubular Cells ◽  
End Products ◽  
Proximal Tubular

Advanced glycated end-products (AGEs) are ligands of the receptor for AGEs and increase in diabetic disease. MAPK organizer 1 (Morg1) via its binding partner prolyl-hydroxylase domain (PHD)-3 presumably plays a role in the regulation of hypoxia-inducible factor (HIF)-1α and HIF-2α transcriptional activation. The purpose of this study was to analyze the influence of AGEs on Morg1 expression and its correlation to PHD3 activity and HIF-transcriptional activity in various renal cell types. The addition of glycated BSA (AGE-BSA) significantly up-regulated Morg1 mRNA levels in murine mesangial cells and down-regulated it in murine proximal tubular cells and differentiated podocytes. These effects were reversible when the cells were preincubated with a receptor for α-AGE antibody. AGE-BSA treatment induced a relocalization of the Morg1 cellular distribution compared with nonglycated control-BSA. Analysis of PHD3 activity demonstrated an elevated PHD3 enzymatic activity in murine mesangial cells but an inhibition in murine proximal tubular cells and podocytes after the addition of AGE-BSA. HIF-transcriptional activity was also affected by AGE-BSA treatment. Reporter gene assays and EMSAs showed that AGEs regulate HIF- transcriptional activity under nonhypoxic conditions in a cell type-specific manner. In proximal tubular cells, AGE-BSA stimulation elevated mainly HIF-1α transcriptional activity and to a lesser extent HIF-2α. We also detected an increased expression of the HIF-1α and the HIF-2α proteins in kidneys from Morg1 heterozygous (HZ) placebo mice compared with the Morg1 wild-type (WT) placebo-treated mice, and the HIF-1α protein expression in the Morg1 HZ streptozotocin-treated mice was significantly higher than the WT streptozotocin-treated mice. Analysis of isolated mesangial cells from Morg1 HZ (±) and WT mice showed an inhibited PHD3 activity and an increased HIF-transcriptional activity in cells with only one Morg1 allele. These findings are important for a better understanding of the molecular mechanisms of diabetic nephropathy.

Managing Resistance to EFGR- and ALK-Targeted Therapies

2017 ◽  
pp. 607-618
Author(s):  
Christine M. Lovly ◽  
Puneeth Iyengar ◽  
Justin F. Gainor
Keyword(s):  
Targeted Therapies ◽  
Molecular Mechanisms ◽  
Acquired Resistance ◽  
Growth Factor Receptor ◽  
Genetic Alterations ◽  
Mechanisms Of Resistance ◽  
Lung Cancers ◽  
Anaplastic Lymphoma ◽  
Ablative Therapies ◽  
Egfr Mutant

Targeted therapies have transformed the management of non–small cell lung cancer (NSCLC) and placed an increased emphasis on stratifying patients on the basis of genetic alterations in oncogenic drivers. To date, the best characterized molecular targets in NSCLC are the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK). Despite steady advances in targeted therapies within these molecular subsets, however, acquired resistance to therapy is near universal. Recent preclinical models and translational efforts have provided critical insights into the molecular mechanisms of resistance to EGFR and ALK inhibitors. In this review, we present a framework for understanding resistance to targeted therapies. We also provide overviews of the molecular mechanisms of resistance and strategies to overcome resistance among EGFR-mutant and ALK-rearranged lung cancers. To date, these strategies have centered on the development of novel next-generation inhibitors, rationale combinations, and use of local ablative therapies, such as radiotherapy.

scholarly journals Genetic exploration of a nuclear receptor transcriptional regulatory complex

2020 ◽  
Author(s):  
Masako Asahina ◽  
Deborah Thurtle-Schmidt ◽  
Keith R. Yamamoto
Keyword(s):  
Nuclear Receptor ◽  
Molecular Mechanisms ◽  
Genetic Screen ◽  
Fluorescent Reporter ◽  
Response Elements ◽  
C Elegans ◽  
Transcriptional Regulatory ◽  
Regulatory Complex ◽  
Composition Structure ◽  
Context Specific

ABSTRACTMetazoan transcriptional regulatory factors (TFs) bind to genomic response elements and assemble with co-regulators into transcriptional regulatory complexes (TRCs) whose composition, structure and activities are gene-, cell- and physiological-context specific. Each TRC is a “regulatory logic module,” integrating incoming signaling information, which defines context and thereby recruits a distinct combination of co-regulators that together specify outgoing regulatory activity. Analyzing TRCs unique to every context is daunting, yet justified by their properties as self-contained regulatory modules. As proof-of-concept, we performed a forward genetic screen in C. elegans carrying a synthetic simple response element for nuclear receptor NHR-25 upstream of a fluorescent reporter gene. We isolated independent mutations in uba-2, a component of the sumoylation signaling machinery, and in lir-2, which we demonstrated to be a novel co-regulator, interacting with NHR-25 through LxxLL motifs and modulating target gene expression. Our studies establish that an unbiased genetic screen readily identifies both afferent and efferent components that specify TRC function, and suggest that screening natural response elements of interest could illuminate molecular mechanisms of both context-specificity and transcriptional regulation.

scholarly journals Brain Metastases in Lung Cancers with Emerging Targetable Fusion Drivers

2020 ◽  
Vol 21 (4) ◽  
pp. 1416 ◽  
Author(s):  
Aaron C. Tan ◽  
Malinda Itchins ◽  
Mustafa Khasraw
Keyword(s):  
Brain Metastases ◽  
Molecular Mechanisms ◽  
Treatment Options ◽  
Growth Factor Receptor ◽  
Standard Of Care ◽  
Driver Mutations ◽  
Lung Cancers ◽  
Anaplastic Lymphoma ◽  
Egfr Mutant ◽  
Line Setting

The management of non-small cell lung cancer (NSCLC) has transformed with the discovery of therapeutically tractable oncogenic drivers. In addition to activating driver mutations, gene fusions or rearrangements form a unique sub-class, with anaplastic lymphoma kinase (ALK) and c-ros oncogene 1 (ROS1) targeted agents approved as the standard of care in the first-line setting for advanced disease. There are a number of emerging fusion drivers, however, including neurotrophin kinase (NTRK), rearrangement during transfection (RET), and neuregulin 1 (NRG1) for which there are evolving high-impact systemic treatment options. Brain metastases are highly prevalent in NSCLC patients, with molecularly selected populations such as epidermal growth factor receptor (EGFR) mutant and ALK-rearranged tumors particularly brain tropic. Accordingly, there exists a substantial body of research pertaining to the understanding of brain metastases in such populations. Little is known, however, on the molecular mechanisms of brain metastases in those with other targetable fusion drivers in NSCLC. This review encompasses key areas including the biological underpinnings of brain metastases in fusion-driven lung cancers, the intracranial efficacy of novel systemic therapies, and future directions required to optimize the control and prevention of brain metastases.

scholarly journals Stabilization but Not the Transcriptional Activity of Herpes Simplex Virus VP16-Induced Complexes Is Evolutionarily Conserved among HCF Family Members

2001 ◽  
Vol 75 (24) ◽  
pp. 12402-12411 ◽  
Author(s):  
Soyoung Lee ◽  
Winship Herr
Keyword(s):  
Cell Proliferation ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Transcriptional Activation ◽  
Early Gene ◽  
Activation Of Transcription ◽  
Transcriptional Regulatory ◽  
Regulatory Complex ◽  
Simplex Virus

ABSTRACT The human herpes simplex virus (HSV) protein VP16 induces formation of a transcriptional regulatory complex with two cellular factors—the POU homeodomain transcription factor Oct-1 and the cell proliferation factor HCF-1—to activate viral immediate-early-gene transcription. Although the cellular role of Oct-1 in transcription is relatively well understood, the cellular role of HCF-1 in cell proliferation is enigmatic. HCF-1 and the related protein HCF-2 form an HCF protein family in humans that is related to a Caenorhabditis elegans homolog called CeHCF. In this study, we show that all three proteins can promote VP16-induced-complex formation, indicating that VP16 targets a highly conserved function of HCF proteins. The resulting VP16-induced complexes, however, display different transcriptional activities. In contrast to HCF-1 and CeHCF, HCF-2 fails to support VP16 activation of transcription effectively. These results suggest that, along with HCF-1, HCF-2 could have a role, albeit probably a different role, in HSV infection. CeHCF can mimic HCF-1 for both association with viral and cellular proteins and transcriptional activation, suggesting that the function(s) of HCF-1 targeted by VP16 has been highly conserved throughout metazoan evolution.

scholarly journals Emerging Molecular Dependencies of Mutant EGFR-Driven Non-Small Cell Lung Cancer

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3553
Author(s):  
Dylan A. Farnsworth ◽  
Yankuan T. Chen ◽  
Georgia de Rappard Yuswack ◽  
William W. Lockwood
Keyword(s):  
Molecular Mechanisms ◽  
Kinase Inhibitors ◽  
Growth Factor Receptor ◽  
Small Cell ◽  
Egfr Mutations ◽  
Small Cell Lung ◽  
Lung Cancers ◽  
Egfr Mutant ◽  
Successive Generations ◽  
Mutant Egfr

Epidermal growth factor receptor (EGFR) mutations are the molecular driver of a subset of non-small cell lung cancers (NSCLC); tumors that harbor these mutations are often dependent on sustained oncogene signaling for survival, a concept known as “oncogene addiction”. Inhibiting EGFR with tyrosine kinase inhibitors has improved clinical outcomes for patients; however, successive generations of inhibitors have failed to prevent the eventual emergence of resistance to targeted agents. Although these tumors have a well-established dependency on EGFR signaling, there remain questions about the underlying genetic mechanisms necessary for EGFR-driven oncogenesis and the factors that allow tumor cells to escape EGFR dependence. In this review, we highlight the latest findings on mutant EGFR dependencies, co-operative drivers, and molecular mechanisms that underlie sensitivity to EGFR inhibitors. Additionally, we offer perspective on how these discoveries may inform novel combination therapies tailored to EGFR mutant NSCLC.

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