scholarly journals Phosphatase and Tensin Homologue: Novel Regulation by Developmental Signaling

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Travis J. Jerde
Keyword(s):  
Growth Factor ◽  
Mammalian Cells ◽  
Hedgehog Signaling ◽  
Transforming Growth Factor ◽  
Signal Transduction Pathway ◽  
Cell Types ◽  
Loss Of Function ◽  
Pten Loss ◽  
Developmental Signaling ◽  
Phosphatase And Tensin Homologue

Phosphatase and tensin homologue (PTEN) is a critical cell endogenous inhibitor of phosphoinositide signaling in mammalian cells. PTEN dephosphorylates phosphoinositide trisphosphate (PIP3), and by so doing PTEN has the function of negative regulation of Akt, thereby inhibiting this key intracellular signal transduction pathway. In numerous cell types, PTEN loss-of-function mutations result in unopposed Akt signaling, producing numerous effects on cells. Numerous reports exist regarding mutations in PTEN leading to unregulated Akt and human disease, most notably cancer. However, less is commonly known about nonmutational regulation of PTEN. This review focuses on an emerging literature on the regulation of PTEN at the transcriptional, posttranscriptional, translational, and posttranslational levels. Specifically, a focus is placed on the role developmental signaling pathways play in PTEN regulation; this includes insulin-like growth factor, NOTCH, transforming growth factor, bone morphogenetic protein, wnt, and hedgehog signaling. The regulation of PTEN by developmental mediators affects critical biological processes including neuronal and organ development, stem cell maintenance, cell cycle regulation, inflammation, response to hypoxia, repair and recovery, and cell death and survival. Perturbations of PTEN regulation consequently lead to human diseases such as cancer, chronic inflammatory syndromes, developmental abnormalities, diabetes, and neurodegeneration.

scholarly journals Cell-Type-Specific Activation of PAK2 by Transforming Growth Factor β Independent of Smad2 and Smad3

2003 ◽  
Vol 23 (23) ◽  
pp. 8878-8889 ◽  
Author(s):  
Mark C. Wilkes ◽  
Stephen J. Murphy ◽  
Nandor Garamszegi ◽  
Edward B. Leof
Keyword(s):  
Growth Factor ◽  
Epithelial Cell ◽  
Mammalian Cells ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Cell Types ◽  
Dominant Negative ◽  
Morphological Alteration ◽  
Morphological Transformation ◽  
Cellular Phenotypes

ABSTRACT Transforming growth factor β (TGF-β) causes growth arrest in epithelial cells and proliferation and morphological transformation in fibroblasts. Despite the ability of TGF-β to induce various cellular phenotypes, few discernible differences in TGF-β signaling between cell types have been reported, with the only well-characterized pathway (the Smad cascade) seemingly under identical control. We determined that TGF-β receptor signaling activates the STE20 homolog PAK2 in mammalian cells. PAK2 activation occurs in fibroblast but not epithelial cell cultures and is independent of Smad2 and/or Smad3. Furthermore, we show that TGF-β-stimulated PAK2 activity is regulated by Rac1 and Cdc42 and dominant negative PAK2 or morpholino antisense oligonucleotides to PAK2 prevent the morphological alteration observed following TGF-β addition. Thus, PAK2 represents a novel Smad-independent pathway that differentiates TGF-β signaling in fibroblast (growth-stimulated) and epithelial cell (growth-inhibited) cultures.

scholarly journals Identification of AKT-regulated genes in inducible MERAkt cells

2001 ◽  
Vol 7 (2) ◽  
pp. 105-114 ◽  
Author(s):  
IRENE KUHN ◽  
MARTY F. BARTHOLDI ◽  
HUGH SALAMON ◽  
RICHARD I. FELDMAN ◽  
RICHARD A. ROTH ◽  
...  
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Critical Role ◽  
Cdna Array ◽  
Signal Transduction Pathway ◽  
Transforming Growth Factor Β ◽  
Oncogenic Transformation ◽  
Nih3t3 Cells ◽  
Estrogen Receptor Ligands ◽  
Phosphoinositide 3 Kinase

AKT/protein kinase B plays a critical role in the phosphoinositide 3-kinase (PI3-kinase) pathway regulating cell growth, differentiation, and oncogenic transformation. Akt1-regulated genes were identified by cDNA array hybridization analysis using an inducible AKT1 protein, MERAKT. Treatment of MERAkt cells with estrogen receptor ligands resulted in phosphorylative activation of MERAKT. Genes differentially expressed in MERAkt/NIH3T3 cells treated with tamoxifen, raloxifene, ICI-182780, and ZK955, were identified at 3 and 20 h. AKT activation resulted in the repression of c-myc, early growth response 1 (EGR1), transforming growth factor β receptor III (TGF-βr III), and thrombospondin-1 (THBS1). Although c-myc induction is often associated with oncogenic transformation, the c-myc repression observed here is consistent with the anti-apoptotic function of AKT. Repression of THBS1 and EGR1 is consistent with the known pro-angiogenic functions of AKT. AKT-regulated genes were found to be largely distinct from platelet-derived growth factor-β (PDGFβ)-regulated genes; only T-cell death-associated gene 51 (TDAG51) was induced in both cases. In contrast to their repression by AKT, c-myc, THBS1, and EGR1 were induced by PDGFβ, indicating negative interference between elements upstream and downstream of AKT1 in the PDGFβ signal transduction pathway.

scholarly journals Transforming Growth Factor β-Mediated Transcriptional Repression of c-myc Is Dependent on Direct Binding of Smad3 to a Novel Repressive Smad Binding Element

2004 ◽  
Vol 24 (6) ◽  
pp. 2546-2559 ◽  
Author(s):  
Joshua P. Frederick ◽  
Nicole T. Liberati ◽  
David S. Waddell ◽  
Yigong Shi ◽  
Xiao-Fan Wang
Keyword(s):  
Growth Factor ◽  
Transcriptional Repression ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Cell Types ◽  
Specific Cell ◽  
Smad Proteins ◽  
Smad Binding Element

ABSTRACT Smad proteins are the most well-characterized intracellular effectors of the transforming growth factor β (TGF-β) signal. The ability of the Smads to act as transcriptional activators via TGF-β-induced recruitment to Smad binding elements (SBE) within the promoters of TGF-β target genes has been firmly established. However, the elucidation of the molecular mechanisms involved in TGF-β-mediated transcriptional repression are only recently being uncovered. The proto-oncogene c-myc is repressed by TGF-β, and this repression is required for the manifestation of the TGF-β cytostatic program in specific cell types. We have shown that Smad3 is required for both TGF-β-induced repression of c-myc and subsequent growth arrest in keratinocytes. The transcriptional repression of c-myc is dependent on direct Smad3 binding to a novel Smad binding site, termed a repressive Smad binding element (RSBE), within the TGF-β inhibitory element (TIE) of the c-myc promoter. The c-myc TIE is a composite element, comprised of an overlapping RSBE and a consensus E2F site, that is capable of binding at least Smad3, Smad4, E2F-4, and p107. The RSBE is distinct from the previously defined SBE and may partially dictate, in conjunction with the promoter context of the overlapping E2F site, whether the Smad3-containing complex actively represses, as opposed to transactivates, the c-myc promoter.

scholarly journals Transforming growth factor–β in tissue fibrosis

2020 ◽  
Vol 217 (3) ◽  
Author(s):  
Nikolaos G. Frangogiannis
Keyword(s):  
Extracellular Matrix ◽  
Growth Factor ◽  
Epithelial Cells ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Cell Types ◽  
Cellular Targets ◽  
Extracellular Matrix Molecules ◽  
Interacting Networks

TGF-β is extensively implicated in the pathogenesis of fibrosis. In fibrotic lesions, spatially restricted generation of bioactive TGF-β from latent stores requires the cooperation of proteases, integrins, and specialized extracellular matrix molecules. Although fibroblasts are major targets of TGF-β, some fibrogenic actions may reflect activation of other cell types, including macrophages, epithelial cells, and vascular cells. TGF-β–driven fibrosis is mediated through Smad-dependent or non-Smad pathways and is modulated by coreceptors and by interacting networks. This review discusses the role of TGF-β in fibrosis, highlighting mechanisms of TGF-β activation and signaling, the cellular targets of TGF-β actions, and the challenges of therapeutic translation.

scholarly journals Endothelial-to-Mesenchymal Transition (EndoMT): Roles in Tumorigenesis, Metastatic Extravasation and Therapy Resistance

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Valentin Platel ◽  
Sébastien Faure ◽  
Isabelle Corre ◽  
Nicolas Clere
Keyword(s):  
Endothelial Cells ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Cell Types ◽  
Therapy Resistance ◽  
Experimental Conditions ◽  
Potential Implication ◽  
Mesenchymal Transition ◽  
Endothelial To Mesenchymal Transition

Cancer cells evolve in a very complex tumor microenvironment, composed of several cell types, among which the endothelial cells are the major actors of the tumor angiogenesis. Today, these cells are also characterized for their plasticity, as endothelial cells have demonstrated their potential to modify their phenotype to differentiate into mesenchymal cells through the endothelial-to-mesenchymal transition (EndoMT). This cellular plasticity is mediated by various stimuli including transforming growth factor-β (TGF-β) and is modulated dependently of experimental conditions. Recently, emerging evidences have shown that EndoMT is involved in the development and dissemination of cancer and also in cancer cell to escape from therapeutic treatment. In this review, we summarize current updates on EndoMT and its main induction pathways. In addition, we discuss the role of EndoMT in tumorigenesis, metastasis, and its potential implication in cancer therapy resistance.

X. Trefoil peptide and EGF receptor/ligand transgenic mice

2000 ◽  
Vol 278 (4) ◽  
pp. G501-G506 ◽  
Author(s):  
Andrew S. Giraud
Keyword(s):  
Growth Factor ◽  
Egf Receptor ◽  
Transforming Growth Factor ◽  
Regulatory Peptides ◽  
Genetically Engineered ◽  
Loss Of Function ◽  
Transforming Growth Factor Α ◽  
Trefoil Peptides ◽  
Trefoil Peptide ◽  
Genetically Engineered Mice

The use of genetically engineered mice with both gain-of-function and loss-of-function mutations has been particularly informative about the normal and pathophysiological actions of a number of regulatory peptides of the gastrointestinal tract. This review highlights some of the major findings pertinent to the epidermal growth factor (EGF) receptor and its ligands, particularly the major gut ligand transforming growth factor-α, as well as the trefoil peptides. Both of these peptide families have important local actions in maintaining tissue homeostasis and repair after injury, and when mechanisms governing their regulation are disrupted they may contribute to disease progression. Future applications of transgenic technology to these areas are likely to be productive in furthering our understanding of the biology of these peptides in health and disease.

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