scholarly journals Human GH Receptor-IGF-1 Receptor Interaction: Implications for GH Signaling

2014 ◽  
Vol 28 (11) ◽  
pp. 1841-1854 ◽  
Author(s):  
Yujun Gan ◽  
Ashiya Buckels ◽  
Ying Liu ◽  
Yue Zhang ◽  
Andrew J. Paterson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Tyrosine Kinase ◽  
Dominant Negative ◽  
Janus Kinase ◽  
Metabolic Effects ◽  
Receptor Interaction ◽  
Tyrosine Kinase Receptor ◽  
Lncap Cells ◽  
Gh Receptor ◽  
Dominant Negative Inhibitor

GH signaling yields multiple anabolic and metabolic effects. GH binds the transmembrane GH receptor (GHR) to activate the intracellular GHR-associated tyrosine kinase, Janus kinase 2 (JAK2), and downstream signals, including signal transducer and activator of transcription 5 (STAT5) activation and IGF-1 gene expression. Some GH effects are partly mediated by GH-induced IGF-1 via IGF-1 receptor (IGF-1R), a tyrosine kinase receptor. We previously demonstrated in non-human cells that GH causes formation of a GHR-JAK2-IGF-1R complex and that presence of IGF-1R (even without IGF-1 binding) augments proximal GH signaling. In this study, we use human LNCaP prostate cancer cells as a model system to further study the IGF-1R's role in GH signaling. GH promoted JAK2 and GHR tyrosine phosphorylation and STAT5 activation in LNCaP cells. By coimmunoprecipitation and a new split luciferase complementation assay, we find that GH augments GHR/IGF-1R complex formation, which is inhibited by a Fab of an antagonistic anti-GHR monoclonal antibody. Short hairpin RNA-mediated IGF-1R silencing in LNCaP cells reduced GH-induced GHR, JAK2, and STAT5 phosphorylation. Similarly, a soluble IGF-1R extracellular domain fragment (sol IGF-1R) interacts with GHR in response to GH and blunts GH signaling. Sol IGF-1R also markedly inhibits GH-induced IGF-1 gene expression in both LNCaP cells and mouse primary osteoblast cells. On the basis of these and other findings, we propose a model in which IGF-1R augments GH signaling by allowing a putative IGF-1R-associated molecule that regulates GH signaling to access the activated GHR/JAK2 complex and envision sol IGF-1R as a dominant-negative inhibitor of this IGF-1R-mediated augmentation. Physiological implications of this new model are discussed.

scholarly journals Aberrant Expression of the Tyrosine Kinase Receptor EphA4 and the Transcription Factor Twist in Sézary Syndrome Identified by Gene Expression Analysis

2004 ◽  
Vol 64 (16) ◽  
pp. 5578-5586 ◽  
Author(s):  
Remco van Doorn ◽  
Remco Dijkman ◽  
Maarten H. Vermeer ◽  
Jacoba J. Out-Luiting ◽  
Elisabeth M. H. van der Raaij-Helmer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Tyrosine Kinase ◽  
Expression Analysis ◽  
Gene Expression Analysis ◽  
Tyrosine Kinase Receptor ◽  
Sézary Syndrome ◽  
Sezary Syndrome ◽  
Aberrant Expression

Expression of truncated Sek-1 receptor tyrosine kinase disrupts the segmental restriction of gene expression in the Xenopus and zebrafish hindbrain

Development ◽  
1995 ◽  
Vol 121 (12) ◽  
pp. 4005-4016 ◽  
Author(s):  
Q. Xu ◽  
G. Alldus ◽  
N. Holder ◽  
D.G. Wilkinson
Keyword(s):  
Gene Expression ◽  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Regulatory Gene ◽  
Cell Lineage ◽  
Cell Movement ◽  
Kinase Domain ◽  
Dominant Negative ◽  
Dynamic Regulation ◽  
Segmental Identity

During development of the vertebrate hindbrain regulatory gene expression is confined to precise segmental domains. Studies of cell lineage and gene expression suggest that establishment of these domains may involve a dynamic regulation of cell identity and restriction of cell movement between segments. We have taken a dominant negative approach to interfere with the function of Sek-1, a member of the Eph-related receptor tyrosine kinase family expressed in rhombomeres r3 and r5. In Xenopus and zebrafish embryos expressing truncated Sek-1, lacking kinase sequences, expression of r3/r5 markers occurs in adjacent even-numbered rhombomeres, in domains contiguous with r3 or r5. This disruption is rescued by full-length Sek-1, indicating a requirement for the kinase domain in the segmental restriction of gene expression. These data suggest that Sek-1, perhaps with other Eph-related receptors, is required for interactions that regulate the segmental identity or movement of cells.

Identification of Common Target Genes of the BCR/ABL and FLT3-ITD Tyrosine Kinases by Microarray Analysis.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3551-3551
Author(s):  
Lolita Banerji ◽  
Blanca Scheijen ◽  
James D. Griffin
Keyword(s):  
Gene Expression ◽  
Tyrosine Kinase ◽  
Cell Lines ◽  
Tyrosine Kinases ◽  
Pcr Analysis ◽  
Tyrosine Kinase Receptor ◽  
Cyclin D2 ◽  
Altered Expression ◽  
Downstream Targets ◽  
Cyclin G2

Abstract Human myeloid leukaemias are commonly associated with activating mutations in tyrosine kinases. The BCR-ABL oncogene causes CML and is generated by the Philadelphia (Ph) chromosome translocation t(9;22)(q34;q11). The FLT3 tyrosine kinase receptor is mutated in about 30 % of all cases of AML, most often through a mechanism that involves an internal tandem duplication (ITD) of a small number of amino acid residues in the juxtamembrane domain. Both BCR/ABL and FLT3 (ITD) produce a constitutively active tyrosine kinase that enhances proliferation and viability of myeloid cells, and induce a similar myeloproliferative disorder when transplanted into mice. In an effort to identify any common downstream targets of BCR/ABL and FLT3(ITD) we generated paired Ba/F3 cell lines in which either Bcr/Abl or FLT3-ITD could be induced under the control of a tetracycline-inducible promoter. Treatment of these cells with doxycycline rapidly induced expression of BCR/ABL or FLT3-ITD proteins, respectively proteins. The gene expression profile of these conditionally expressing BCR/ABL and FLT3-ITD BaF3cells was examined using the U430A gene chip (Affymetrix), which contains more than 34000 well substantiated genes. With a 2.5 fold cut-off, Bcr/Abl altered the expression of 336 genes and FLT3-ITD altered expression of 231 genes at 24 hours after induction. Fifty one genes were regulated by both Bcr/Abl and FLT3-ITD, including Cyclin G2, cyclin D2, CXCR4, osteopontin and FKBP12. Following induction of BCR/ABL and FLT3-ITD, cyclin D2, osteopontin and FKBP12 are strongly upregulated, whereas cyclin G2 and CXCR4 are downregulated. We validated the expression pattern of these genes by real-time PCR analysis. To further validate that these genes are directly regulated by the kinase activity of BCR/ABL and FLT3-ITD, cell lines were treated with specific small molecule kinase inhibitors, resulting in both cases in a significant decrease in cyclin D2, osteopontin, and FKBP12 and an increase in cyclin G2 and CXCR4 expression. The functional role of several of these genes is under investigation. For example, we found that the PI3K/AKT pathway is important for regulating osteopontin gene expression, and that osteopontin is involved in mediating the increase in cell growth caused by both BCR/ABL and FLT3-ITD. The identification of downstream targets, such as cyclins, osteopontin, and others, that are shared in common by several oncogenic tyrosine kinase oncogenes suggest that they could have value as therapeutic targets.

scholarly journals Phosphoproteome and gene expression profiling of ALK inhibition in neuroblastoma cell lines reveals conserved oncogenic pathways

2018 ◽  
Vol 11 (557) ◽  
pp. eaar5680 ◽  
Author(s):  
Jimmy Van den Eynden ◽  
Ganesh Umapathy ◽  
Arghavan Ashouri ◽  
Diana Cervantes-Madrid ◽  
Joanna Szydzik ◽  
...  
Keyword(s):  
Gene Expression ◽  
Tyrosine Kinase ◽  
Molecular Mechanisms ◽  
Kinase Inhibitors ◽  
Expression Profiles ◽  
Neuroblastoma Cell ◽  
Treatment Strategies ◽  
Tyrosine Kinase Receptor ◽  
Anaplastic Lymphoma ◽  
Major Interest

Anaplastic lymphoma kinase (ALK) is a tyrosine kinase receptor that is a clinical target of major interest in cancer. Mutations and rearrangements inALKtrigger the activation of the encoded receptor and its downstream signaling pathways.ALKmutations have been identified in both familial and sporadic neuroblastoma cases as well as in 30 to 40% of relapses, which makes ALK a bona fide target in neuroblastoma therapy. Tyrosine kinase inhibitors (TKIs) that target ALK are currently in clinical use for the treatment of patients with ALK-positive non–small cell lung cancer. However, monotherapy with the ALK inhibitor crizotinib has been less encouraging in neuroblastoma patients withALKalterations, raising the question of whether combinatorial therapy would be more effective. In this study, we established both phosphoproteomic and gene expression profiles of ALK activity in neuroblastoma cells exposed to first- and third-generation ALK TKIs, to identify the underlying molecular mechanisms and identify relevant biomarkers, signaling networks, and new therapeutic targets. This analysis has unveiled various important leads for novel combinatorial treatment strategies for patients with neuroblastoma and an increased understanding of ALK signaling involved in this disease.

scholarly journals Transcriptional and Metabolic Effects of Glucocorticoid Receptor α and β Signaling in Zebrafish

Endocrinology ◽  
2015 ◽  
Vol 156 (5) ◽  
pp. 1757-1769 ◽  
Author(s):  
Antonia Chatzopoulou ◽  
Upasana Roy ◽  
Annemarie H. Meijer ◽  
A. Alia ◽  
Herman P. Spaink ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Splice Variants ◽  
Gene Clusters ◽  
Dominant Negative ◽  
Metabolic Effects ◽  
Resonance Spectroscopy ◽  
Zebrafish Model ◽  
Receptor Isoforms ◽  
Endogenous Cortisol ◽  
Dominant Negative Inhibitor

In humans and zebrafish, 2 glucocorticoid (GC) receptor (GR) splice variants exist: the canonical GR α-isoform (GRα), and the GRβ. In the present study, we have used the zebrafish model system in order to reveal genes affected by each of these 2 receptor isoforms. By injecting zebrafish embryos with different splice-blocking morpholinos, we could knock down both GR isoforms or could target the alternative splicing of the GR pre-mRNA in favor of the GRβ. In addition, specific GRβ overexpression was achieved by injecting mRNA. Embryos were treated with the synthetic GC dexamethasone, and transcriptome analysis was performed. Two distinct gene clusters were found that were regulated by GRα: one that was regulated by GRα under basal conditions (presence of endogenous cortisol only), and one that was regulated upon increased activation of GRα (using a pharmacological dose of dexamathasone). GRβ may act as a dominant-negative inhibitor of GRα when GRβ is overexpressed and the GRα expression level is knocked down simultaneously. However, without GRα knockdown, no evidence for this activity was found. In addition, the data indicate regulation of gene transcription through other mechanisms of action by GRβ. We also investigated the concentrations of several metabolites using nuclear magnetic resonance spectroscopy. We found that dexamethasone treatment and knockdown of GRα together with overexpression of GRβ had opposite effects on glucose, amino acid, and fatty acid levels. Thus, we have shed new light on the molecular mechanisms of GC-induced effects on metabolism, which are known to increase the risk of obesity, hyperglycemia, and diabetes.

scholarly journals Microarray analyses identify JAK2 tyrosine kinase as a key mediator of ligand-independent gene expression

2004 ◽  
Vol 287 (4) ◽  
pp. C981-C991 ◽  
Author(s):  
Tiffany A. Wallace ◽  
Dannielle VonDerLinden ◽  
Kai He ◽  
Stuart J. Frank ◽  
Peter P. Sayeski
Keyword(s):  
Gene Expression ◽  
Target Genes ◽  
Dominant Negative ◽  
Janus Kinase ◽  
Pcr Analysis ◽  
Expression Levels ◽  
Surface Receptors ◽  
Downstream Target ◽  
Dominant Negative Allele

Mice lacking a functional Janus kinase 2 (JAK2) allele die embryonically, indicating the mandatory role of JAK2 in basic developmental cellular transcription. Currently, however, the downstream target genes of JAK2 are largely unknown. Here, in vitro conditions were created using a cell line lacking JAK2 expression. Microarray analysis was then used to identify genes that are differentially expressed as a result of the presence, or absence, of JAK2. The data identified 621 JAK2-dependent genes as having at least a twofold change in expression. Surprisingly, these genes did not require ligand-dependent activation of JAK2 but merely its expression in the cell. Thirty-one of these genes were found to have a greater than sevenfold change in expression levels, and a subset of these were further characterized. These genes represent a diverse cluster of ontological functions including transcription factors, signaling molecules, and cell surface receptors. The expression levels of these genes were validated by Northern blot and/or quantitative RT-PCR analysis in both the JAK2 null cells and cells expressing a JAK2-dominant negative allele. As such, this work demonstrates for the first time that, in addition to being a key mediator of ligand-activated gene transcription, JAK2 can perhaps also be viewed as a critical mediator of basal level gene expression.

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