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Sample records for biotinylated receptor tyrosine

  1. Biotinylated recombinant human erythropoietins: Bioactivity and utility as receptor ligand

    Energy Technology Data Exchange (ETDEWEB)

    Wojchowski, D.M.; Caslake, L. (Pennsylvania State Univ., University Park (USA))

    1989-08-15

    Recombinant human erythropoietin labeled covalently with biotin at sialic acid moieties has been prepared, and has been shown to possess high biological activity plus utility as a receptor ligand. Initially, the effects on biological activity of covalently attaching biotin to erythropoietin alternatively at carboxylate, amino, or sialic acid groups were compared. Biotinylation of erythropoietin at carboxylate groups using biotin-amidocaproyl hydrazide plus 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide led to substantial biological inactivation, although biotinylated molecules retained detectable activity when prepared at low stoichiometries. Biotinylation at amino groups using sulfosuccinimidyl 6-(biotinamido) hexanoate resulted in a high level of biological inactivation with little, if any, retention of biological activity, regardless of labeling stoichiometries. Biotinylation at sialic acid moieties using periodate and biotinamidocaproyl hydrazide proceeded efficiently (greater than 95% and 80% labeling efficiencies for human urinary and recombinant erythropoietin, respectively) and yielded stably biotinylated erythropoietin molecules possessing comparably high biological activity (ie, 45% of the activity of unmodified hormone). Utility of recombinant biotin-(sialyl)-erythropoietin (in combination with 125I-streptavidin) in the assay of cell surface receptors was demonstrated using two distinct murine erythroleukemia cell lines, Friend 745 and Rauscher Red 1. The densities and affinities of specific hormone binding sites were 116 +/- 4 sites, 3.3 +/- 0.4 nmol/L kd and 164 +/- 5 sites, 2.7 +/- 0.4 nmol/L kd, respectively. It is predicted that the present development of biotin-(sialyl)-erythropoietin as a chemically and biologically stable, bioactive ligand will assist in advancing an understanding of the regulated expression and physicochemistry of the human and murine erythropoietin receptors.

  2. MET Receptor Tyrosine Kinase

    Science.gov (United States)

    Faoro, Leonardo; Cervantes, Gustavo M.; El-Hashani, Essam; Salgia, Ravi

    2010-01-01

    MET receptor tyrosine kinase (RTK) and its ligand hepatocyte growth factor (HGF) have become important therapeutic target in oncology, especially lung cancer. MET RTK is involved in cancer cell growth/survival, motility/migration, invasion/metastasis, and in angiogenesis. MET can be overexpressed in lung cancer, sometimes mutated, and sometimes amplified. Not only can MET be overexpressed, there are subsets of lung cancer tumors that have HGF overexpression. The mutations of MET can occur in the semaphorin and/or juxtamembrane domain in a majority of times. Amplification of MET can occur de novo in primary/metastatic tumors, as well arise in the context of therapeutic inhibition. There are a number of clinical inhibitors that have been developed against MET/HGF. Small molecule inhibitors such as XL184 and PF02341066 have come to clinical fruition, as well as antibodies against MET (such as MetMAb). These inhibitors will be discussed. PMID:19861919

  3. Tyrosine phosphorylation of the asialoglycoprotein receptor

    International Nuclear Information System (INIS)

    The asialoglycoprotein (ASGP) receptor undergoes constitutive endocytosis through the coated pit/coated vesicle pathway in hepatocytes. Studies on HepG2 cells have shown that the receptor is phosphorylated at serine under control conditions and following protein kinase C stimulation. This study examined whether the ASGP receptor could also serve as a substrate for a tyrosine kinase in HepG2 cells. 32P labeling was performed in membrane preparations, in permeabilized cells at 4 degrees C, and in intact cells at 37 degrees C. The phosphorylated ASGP receptor was isolated by immunoprecipitation, hydrolyzed in 6 N HCl at 110 degrees C, and analyzed by two-dimensional high voltage electrophoresis. The receptor isolated from a membrane preparation incubated in vitro with [gamma-32P]ATP incorporated radiolabel predominantly (greater than 90%) into phosphotyrosine. ASGP receptor phosphorylation at both tyrosine and serine was detected in intact cells incubated with phosphatase inhibitors for 60 min at 37 degrees C. The presence of both phenylarsine oxide (20 microM) and sodium orthovanadate (200 microM) was required for tyrosine phosphorylation. Use of these inhibitors together resulted in a 16.4-fold increase in phosphorylation of the immunoprecipitated ASGP receptor, whereas phosphorylation of total HepG2 membrane proteins was not significantly augmented by this procedure. Selective proteolytic digestion of ASGP receptors in isolated vesicles demonstrated that the phosphorylation site identified in these studies is located at tyrosine 5 in the cytoplasmic tail

  4. Complexity of Receptor Tyrosine Kinase Signal Processing

    OpenAIRE

    Volinsky, Natalia; Kholodenko, Boris N.

    2013-01-01

    Our knowledge of molecular mechanisms of receptor tyrosine kinase (RTK) signaling advances with ever-increasing pace. Yet our understanding of how the spatiotemporal dynamics of RTK signaling control specific cellular outcomes has lagged behind. Systems-centered experimental and computational approaches can help reveal how overlapping networks of signal transducers downstream of RTKs orchestrate specific cell-fate decisions. We discuss how RTK network regulatory structures, which involve the ...

  5. DMPD: Receptor tyrosine kinases and the regulation of macrophage activation. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 14726496 Receptor tyrosine kinases and the regulation of macrophage activation. Cor...(.csml) Show Receptor tyrosine kinases and the regulation of macrophage activation. PubmedID 14726496 Title Receptor tyrosine kinases

  6. Receptor tyrosine kinase targeting in multicellular spheroids.

    Science.gov (United States)

    Breslin, Susan; O'Driscoll, Lorraine

    2015-01-01

    While growing cells as a monolayer is the traditional method for cell culture, the incorporation of multicellular spheroids into experimental design is becoming increasingly popular. This is due to the understanding that cells grown as spheroids tend to replicate the in vivo situation more reliably than monolayer cells. Thus, the use of multicellular spheroids may be more clinically relevant than monolayer cell cultures. Here, we describe methods for multicellular 3D spheroid generation that may be used to provide samples for receptor tyrosine kinase (and other protein) detection. Methods described include the forced-floating poly-HEMA method, the hanging-drop method, and the use of ECM to form multicellular 3D spheroids. PMID:25319898

  7. Complexity of Receptor Tyrosine Kinase Signal Processing

    Science.gov (United States)

    Volinsky, Natalia; Kholodenko, Boris N.

    2013-01-01

    Our knowledge of molecular mechanisms of receptor tyrosine kinase (RTK) signaling advances with ever-increasing pace. Yet our understanding of how the spatiotemporal dynamics of RTK signaling control specific cellular outcomes has lagged behind. Systems-centered experimental and computational approaches can help reveal how overlapping networks of signal transducers downstream of RTKs orchestrate specific cell-fate decisions. We discuss how RTK network regulatory structures, which involve the immediate posttranslational and delayed transcriptional controls by multiple feed forward and feedback loops together with pathway cross talk, adapt cells to the combinatorial variety of external cues and conditions. This intricate network circuitry endows cells with emerging capabilities for RTK signal processing and decoding. We illustrate how mathematical modeling facilitates our understanding of RTK network behaviors by unraveling specific systems properties, including bistability, oscillations, excitable responses, and generation of intricate landscapes of signaling activities. PMID:23906711

  8. Receptor Tyrosine Kinases — Expanding Horizons

    Directory of Open Access Journals (Sweden)

    Sassan Hafizi

    2014-06-01

    Full Text Available This Special Issue of Cells on receptor tyrosine kinases (RTKs is a timely and unique assemblage of scholarly insights into topics that have relatively recently entered the spotlight in relation to this class of molecules. The review by Julien et al. [1] is an overview of the knowledge on how gangliosides, constituting certain membrane microdomains, may interact with and regulate RTK activation and downstream signalling. Similarly, the review by Banning et al. [2] focuses on the influence of another type of membrane microdomain, namely that containing flotillins, on regulation of RTK signalling and its relevance to cancer. Both of these reviews provide novel insights into mechanisms of transmembrane receptor signalling that rely on the constitution of the microdomains the RTKs reside in, and how their modification may affect receptor clustering, activation and translocation. Thus, knowledge about such microdomains and their interactions with RTKs can provide new information on common regulation pathways starting at the membrane level, which could have implications for novel therapeutic angles in, e.g., cancer. [...

  9. Tyrosine kinase signalling in breast cancer: ErbB family receptor tyrosine kinases

    International Nuclear Information System (INIS)

    ERBB family receptor tyrosine kinases are overexpressed in a significant subset of breast cancers. One of these receptors, HER2/neu, or ErbB-2, is the target for a new rational therapeutic antibody, Herceptin. Other inhibitors that target this receptor, and another family member, the epidermal growth factor (EGF) receptor, are moving into clinical trials. Both of these receptors are sometimes overexpressed in breast cancer, and still subject to regulation by hormones and other physiological regulators. Optimal use of therapeutics targeting these receptors will require consideration of the several modes of regulation of these receptors and their interactions with steroid receptors

  10. BRET biosensor analysis of receptor tyrosine kinase functionality

    Directory of Open Access Journals (Sweden)

    StuartMaudsley

    2013-04-01

    Full Text Available Bioluminescence resonance energy transfer (BRET is an improved version of earlier resonance energy transfer technologies used for the analysis of biomolecular protein interaction. BRET analysis can be applied to many transmembrane receptor classes, however the majority of the early published literature on BRET has focused on G protein-coupled receptor (GPCR research. In contrast, there is limited scientific literature using BRET to investigate receptor tyrosine kinase (RTK activity. This limited investigation is surprising as RTKs often employ dimerization as a key factor in their activation, as well as being important therapeutic targets in medicine, especially in the cases of cancer, diabetes, neurodegenerative and respiratory conditions. In this review, we consider an array of studies pertinent to RTKs and other non-GPCR receptor protein-protein signaling interactions; more specifically we discuss receptor-protein interactions involved in the transmission of signaling communication. We have provided an overview of functional BRET studies associated with the receptor tyrosine kinase (RTK super family involving: neurotrophic receptors (e.g. tropomyosin-related kinase (Trk and p75 neurotrophin receptor (p75NTR; insulinotropic receptors (e.g. insulin receptor (IR and insulin-like growth factor receptor (IGFR and growth factor receptors (e.g. ErbB receptors including the EGFR, the fibroblast growth factor receptor (FGFR, the vascular endothelial growth factor receptor (VEGFR and the c-kit and platelet-derived growth factor receptor (PDGFR. In addition, we review BRET-mediated studies of other tyrosine kinase-associated receptors including cytokine receptors, i.e. leptin receptor (OB-R and the growth hormone receptor (GHR. It is clear even from the relatively sparse experimental RTK BRET evidence that there is tremendous potential for this technological application for the functional investigation of RTK biology.

  11. Receptor-type protein tyrosine phosphatases in cancer

    Directory of Open Access Journals (Sweden)

    Yu Du

    2015-02-01

    Full Text Available Protein tyrosine phosphatases (PTPs play an important role in regulating cell signaling events in coordination with tyrosine kinases to control cell proliferation, apoptosis, survival, migration, and invasion. Receptor-type protein tyrosine phosphatases (PTPRs are a subgroup of PTPs that share a transmembrane domain with resulting similarities in function and target specificity. In this review, we summarize genetic and epigenetic alterations including mutation, deletion, amplification, and promoter methylation of PTPRs in cancer and consider the consequences of PTPR alterations in different types of cancers. We also summarize recent developments using PTPRs as prognostic or predictive biomarkers and/or direct targets. Increased understanding of the role of PTPRs in cancer may provide opportunities to improve therapeutic approaches.

  12. Antigen receptor signaling: integration of protein tyrosine kinase functions.

    Science.gov (United States)

    Tamir, I; Cambier, J C

    1998-09-17

    Antigen receptors on T and B cells function to transduce signals leading to a variety of biologic responses minimally including antigen receptor editing, apoptotic death, developmental progression, cell activation, proliferation and survival. The response to antigen depends upon antigen affinity and valence, involvement of coreceptors in signaling and differentiative stage of the responding cell. The requirement that these receptors integrate signals that drive an array of responses may explain their evolved structural complexity. Antigen receptors are composed of multiple subunits compartmentalized to provide antigen recognition and signal transduction function. In lieu of on-board enzymatic activity these receptors rely on associated Protein Tyrosine Kinases (PTKs) for their signaling function. By aggregating the receptors, and hence their appended PTKs, antigens induce PTK transphosphorylation, activating them to phosphorylate the receptor within conserved motifs termed Immunoreceptor Tyrosine-based Activation Motifs (ITAMs) found in transducer subunits. The tyrosyl phosphorylated ITAMs then interact with Src Homology 2 (SH2) domains within the PTKs leading to their further activation. As receptor phosphorylation is amplified, other effectors, such as Shc, dock by virtue of SH2 binding, and serve, in-turn, as substrates for these PTKs. This sequence of events not only provides a signal amplification mechanism by combining multiple consecutive steps with positive feedback, but also allows for signal diversification by differential recruitment of effectors that provide access to distinct parallel downstream signaling pathways. The subject of antigen receptor signaling has been recently reviewed in depth (DeFranco, 1997; Kurosaki, 1997). Here we discuss the biochemical basis of antigen receptor signal transduction, using the B cell receptor (BCR) as a paradigm, with specific emphasis on the involved PTKs. We review several specific mechanisms by which responses

  13. Tyrosine kinase JAK1 is associated with the granulocyte-colony-stimulating factor receptor and both become tyrosine-phosphorylated after receptor activation.

    OpenAIRE

    Nicholson, S. E.; Oates, A. C.; Harpur, A G; Ziemiecki, A; Wilks, A F; Layton, J E

    1994-01-01

    Granulocyte-colony-stimulating factor (G-CSF) stimulates the proliferation and differentiation of cells of the neutrophil lineage by interaction with a specific receptor. Early signal transduction events following G-CSF receptor activation were studied. We detected tyrosine phosphorylation of both the G-CSF receptor and the protein tyrosine kinase JAK1 following G-CSF binding to the human G-CSF receptor. In vitro, the kinase activity of JAK1 was increased by G-CSF stimulation. Coimmunoprecipi...

  14. The role of GH receptor tyrosine phosphorylation in Stat5 activation

    DEFF Research Database (Denmark)

    Hansen, J A; Hansen, L H; Wang, X;

    1997-01-01

    phosphorylated GST-GH receptor fusion proteins specifically bound to Stat5 in extracts from COS 7 cells transfected with Stat5 cDNA. This binding could be inhibited by tyrosine phosphorylated peptides derived from the GH receptor. This study thus demonstrated that specific GH receptor tyrosine residues, in their...

  15. Asymmetric Receptor Contact is Required for Tyrosine Autophosphorylation of Fibroblast Growth Factor Receptor in Living Cells

    Energy Technology Data Exchange (ETDEWEB)

    Bae, J.; Boggon, T; Tomé, F; Mandiyan, V; Lax, I; Schlessinge, J

    2010-01-01

    Tyrosine autophosphorylation of receptor tyrosine kinases plays a critical role in regulation of kinase activity and in recruitment and activation of intracellular signaling pathways. Autophosphorylation is mediated by a sequential and precisely ordered intermolecular (trans) reaction. In this report we present structural and biochemical experiments demonstrating that formation of an asymmetric dimer between activated FGFR1 kinase domains is required for transphosphorylation of FGFR1 in FGF-stimulated cells. Transphosphorylation is mediated by specific asymmetric contacts between the N-lobe of one kinase molecule, which serves as an active enzyme, and specific docking sites on the C-lobe of a second kinase molecule, which serves a substrate. Pathological loss-of-function mutations or oncogenic activating mutations in this interface may hinder or facilitate asymmetric dimer formation and transphosphorylation, respectively. The experiments presented in this report provide the molecular basis underlying the control of transphosphorylation of FGF receptors and other receptor tyrosine kinases.

  16. Redundant and selective roles for erythropoietin receptor tyrosines in erythropoiesis in vivo.

    Science.gov (United States)

    Longmore, G D; You, Y; Molden, J; Liu, K D; Mikami, A; Lai, S Y; Pharr, P; Goldsmith, M A

    1998-02-01

    Cytokine receptors have been shown in cell culture systems to use phosphotyrosine residues as docking sites for certain signal transduction intermediates. Studies using various cellular backgrounds have yielded conflicting information about the importance of such residues. The present studies were undertaken to determine whether or not tyrosine residues within the erythropoietin receptor (EPOR) are essential for biologic activity during hematopoiesis in vivo. A variant of the EPOR was constructed that contains both a substitution (R129C) causing constitutive receptor activation as well as replacement of all eight cytoplasmic tyrosines by phenylalanines (cEPORYF). A comparison between animals exposed to recombinant retroviruses expressing cEPOR and cEPORYF showed that efficient red blood cell (RBC) development in vivo is dependent on the pressence of tyrosine residues in the cytoplasmic domain of the EPOR. In addition, an inefficient EPOR tyrosine independent pathway supporting RBC development was detected. Tyrosine add-back mutants showed that multiple individual tyrosines have the capacity to restore full erythropoietic potential to the EPOR as determined in whole animals. The analysis of primary erythroid progenitors transduced with the various cEPOR tyrosine mutants and tyrosine add-backs showed that only tyrosine 343 (Y1) and tyrosine 479 (Y8) were capable of supporting immature burst-forming unit-erythroid progenitor development. Thus, this receptor is characterized by striking functional redundancy of tyrosines in a biologically relevant context. However, selective tyrosine residues may be uniquely important for early signals supporting erythroid development. PMID:9446647

  17. Profiling Epidermal Growth Factor Receptor and Heregulin Receptor 3 Heteromerization Using Receptor Tyrosine Kinase Heteromer Investigation Technology

    OpenAIRE

    Mohammed Akli Ayoub; Heng B See; Seeber, Ruth M.; Armstrong, Stephen P.; Pfleger, Kevin D.G.

    2013-01-01

    Heteromerization can play an important role in regulating the activation and/or signal transduction of most forms of receptors, including receptor tyrosine kinases (RTKs). The study of receptor heteromerization has evolved extensively with the emergence of resonance energy transfer based approaches such as bioluminescence resonance energy transfer (BRET). Here, we report an adaptation of our Receptor-Heteromer Investigation Technology (Receptor-HIT) that has recently been published as the G p...

  18. Protein-tyrosine-phosphatase SHPTP2 couples platelet-derived growth factor receptor beta to Ras.

    OpenAIRE

    Bennett, A.M.; Tang, T. L.; SUGIMOTO, S; Walsh, C T; Neel, B G

    1994-01-01

    Protein-tyrosine-phosphatase SHPTP2 (Syp/PTP-1D/PTP2C) is the homologue of the Drosophila corkscrew (csw) gene product, which transmits positive signals from receptor tyrosine kinases. Likewise, SHPTP2 has been implicated in positive signaling from platelet-derived growth factor receptor beta (PDGFR). Upon PDGF stimulation, SHPTP2 binds to the PDGFR and becomes tyrosine-phosphorylated. We have identified tyrosine-542 (pY542TNI) as the major in vivo site of SHPTP2 tyrosine phosphorylation. The...

  19. Tyrosine phosphorylation of the human guanylyl cyclase C receptor

    Indian Academy of Sciences (India)

    Rashna Bhandari; Roy Mathew; K Vijayachandra; Sandhya S Visweswariah

    2000-12-01

    Tyrosine phosphorylation events are key components of several cellular signal transduction pathways. This study describes a novel method for identification of substrates for tyrosine kinases. Co-expression of the tyrosine kinase EphB1 with the intracellular domain of guanylyl cyclase C (GCC) in Escherichia coli cells resulted in tyrosine phosphorylation of GCC, indicating that GCC is a potential substrate for tyrosine kinases. Indeed, GCC expressed in mammalian cells is tyrosine phosphorylated, suggesting that tyrosine phosphorylation may play a role in regulation of GCC signalling. This is the first demonstration of tyrosine phosphorylation of any member of the family of membrane-associated guanylyl cyclases.

  20. SOCS proteins in regulation of receptor tyrosine kinase signaling

    DEFF Research Database (Denmark)

    Kazi, Julhash U.; Kabir, Nuzhat N.; Flores Morales, Amilcar;

    2014-01-01

    signaling mediated by RTKs must be tightly regulated by interacting proteins including protein-tyrosine phosphatases and ubiquitin ligases. The suppressors of cytokine signaling (SOCS) family proteins are well-known negative regulators of cytokine receptors signaling consisting of eight structurally similar...... proteins, SOCS1-7, and cytokine-inducible SH2-containing protein (CIS). A key feature of this family of proteins is the presence of an SH2 domain and a SOCS box. Recent studies suggest that SOCS proteins also play a role in RTK signaling. Activation of RTK results in transcriptional activation of SOCS......-encoding genes. These proteins associate with RTKs through their SH2 domains and subsequently recruit the E3 ubiquitin machinery through the SOCS box, and thereby limit receptor stability by inducing ubiquitination. In a similar fashion, SOCS proteins negatively regulate mitogenic signaling by RTKs. It is also...

  1. Mechanisms of Activation of Receptor Tyrosine Kinases: Monomers or Dimers

    Directory of Open Access Journals (Sweden)

    Ichiro N. Maruyama

    2014-04-01

    Full Text Available Receptor tyrosine kinases (RTKs play essential roles in cellular processes, including metabolism, cell-cycle control, survival, proliferation, motility and differentiation. RTKs are all synthesized as single-pass transmembrane proteins and bind polypeptide ligands, mainly growth factors. It has long been thought that all RTKs, except for the insulin receptor (IR family, are activated by ligand-induced dimerization of the receptors. An increasing number of diverse studies, however, indicate that RTKs, previously thought to exist as monomers, are present as pre-formed, yet inactive, dimers prior to ligand binding. The non-covalently associated dimeric structures are reminiscent of those of the IR family, which has a disulfide-linked dimeric structure. Furthermore, recent progress in structural studies has provided insight into the underpinnings of conformational changes during the activation of RTKs. In this review, I discuss two mutually exclusive models for the mechanisms of activation of the epidermal growth factor receptor, the neurotrophin receptor and IR families, based on these new insights.

  2. Receptor tyrosine kinase structure and function in health and disease

    Directory of Open Access Journals (Sweden)

    Oleg A. Karpov

    2015-09-01

    Full Text Available Receptor tyrosine kinases (RTKs are membrane proteins that control the flow of information through signal transduction pathways, impacting on different aspects of cell function. RTKs are characterized by a ligand-binding ectodomain, a single transmembrane α-helix, a cytosolic region comprising juxtamembrane and kinase domains followed by a flexible C-terminal tail. Somatic and germline RTK mutations can induce aberrant signal transduction to give rise to cardiovascular, developmental and oncogenic abnormalities. RTK overexpression occurs in certain cancers, correlating signal strength and disease incidence. Diverse RTK activation and signal transduction mechanisms are employed by cells during commitment to health or disease. Small molecule inhibitors are one means to target RTK function in disease initiation and progression. This review considers RTK structure, activation, and signal transduction and evaluates biological relevance to therapeutics and clinical outcomes.

  3. Receptor Tyrosine Kinases: Molecular Switches Regulating CNS Axon Regeneration

    Directory of Open Access Journals (Sweden)

    Vasanthy Vigneswara

    2012-01-01

    Full Text Available The poor or lack of injured adult central nervous system (CNS axon regeneration results in devastating consequences and poor functional recovery. The interplay between the intrinsic and extrinsic factors contributes to robust inhibition of axon regeneration of injured CNS neurons. The insufficient or lack of trophic support for injured neurons is considered as one of the major obstacles contributing to their failure to survive and regrow their axons after injury. In the CNS, many of the signalling pathways associated with neuronal survival and axon regeneration are regulated by several classes of receptor tyrosine kinases (RTK that respond to a variety of ligands. This paper highlights and summarises the most relevant recent findings pertinent to different classes of the RTK family of molecules, with a particular focus on elucidating their role in CNS axon regeneration.

  4. Growth hormone-dependent phosphorylation of tyrosine 333 and/or 338 of the growth hormone receptor

    DEFF Research Database (Denmark)

    VanderKuur, J A; Wang, X; Zhang, L;

    1995-01-01

    Many signaling pathways initiated by ligands that activate receptor tyrosine kinases have been shown to involve the binding of SH2 domain-containing proteins to specific phosphorylated tyrosines in the receptor. Although the receptor for growth hormone (GH) does not contain intrinsic tyrosine...

  5. DMPD: Macrophage-stimulating protein and RON receptor tyrosine kinase: potentialregulators of macrophage inflammatory activities. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 12472665 Macrophage-stimulating protein and RON receptor tyrosine kinase: potential...:545-53. (.png) (.svg) (.html) (.csml) Show Macrophage-stimulating protein and RON receptor tyrosine kinase: poten...le Macrophage-stimulating protein and RON receptor tyrosine kinase: potentialregulators of macrophage inflam

  6. Metazoan-like signaling in a unicellular receptor tyrosine kinase

    Directory of Open Access Journals (Sweden)

    Schultheiss Kira P

    2013-02-01

    Full Text Available Abstract Background Receptor tyrosine kinases (RTKs are crucial components of signal transduction systems in multicellular animals. Surprisingly, numerous RTKs have been identified in the genomes of unicellular choanoflagellates and other protists. Here, we report the first biochemical study of a unicellular RTK, namely RTKB2 from Monosiga brevicollis. Results We cloned, expressed, and purified the RTKB2 kinase, and showed that it is enzymatically active. The activity of RTKB2 is controlled by autophosphorylation, as in metazoan RTKs. RTKB2 possesses six copies of a unique domain (designated RM2 in its C-terminal tail. An isolated RM2 domain (or a synthetic peptide derived from the RM2 sequence served as a substrate for RTKB2 kinase. When phosphorylated, the RM2 domain bound to the Src homology 2 domain of MbSrc1 from M. brevicollis. NMR structural studies of the RM2 domain indicated that it is disordered in solution. Conclusions Our results are consistent with a model in which RTKB2 activation stimulates receptor autophosphorylation within the RM2 domains. This leads to recruitment of Src-like kinases (and potentially other M. brevicollis proteins and further phosphorylation, which may serve to increase or dampen downstream signals. Thus, crucial features of signal transduction circuitry were established prior to the evolution of metazoans from their unicellular ancestors.

  7. Influence of berberine on protein tyrosine kinase of erythrocyte insulin receptors from type 2 diabetes mellitus

    Institute of Scientific and Technical Information of China (English)

    Xianglei Deng; Xinrong Li; Chenggong Tian

    2005-01-01

    Objective: Bererine has been used to treat type 2 diabetes mellitus in Chinese traditional medicine because of its hypoglycemic effect. In this report, we compared the intrinsic tyrosine kinase activities of erythrocyte insulin receptors from type 2 diabetes mellitus with or without stimulation by berberine in vitro. Methods: Preparations containing insulin receptors were obtained from soluble human erythrocytes, and the insulin receptors were partially purified by affinity chromatography. The tyrosine kinase activity was measured by the exogenous substrate phosphorylation. Results: Both the membrane tyrosine kinase activity and the purified receptor tyrosine kinase activity from diabetics decreased significantly compared with those of normal individuals (reduced by 67.4 % and 47.2 %, respectively).After incubation with berberine, there is a statistical difference in the activity of membrane tyrosine kinase for diabetic patients (a 150% increase). Bererine had no effect on the tyrosine kinase activity of purified insulin receptors. Conclusion: We concluded from these results that berberine was able to improve the insulin sensitivity by increasing the protein tyrosine kinase activity of membrane-bound insulin receptors from type 2 diabetes mellitus.

  8. Multiple autophosphorylation sites of the epidermal growth factor receptor are essential for receptor kinase activity and internalization. Contrasting significance of tyrosine 992 in the native and truncated receptors

    DEFF Research Database (Denmark)

    Sorkin, A; Helin, K; Waters, C M; Carpenter, G; Beguinot, L

    1992-01-01

    similar to a kinase-negative receptor. Mutation of tyrosine residue Y992 alone in the context of full length EGF receptor, however, did not affect receptor internalization or kinase activity toward phospholipase C-gamma 1. These data indicate that tyrosine 992 is critical for substrate phosphorylation and...... internalization only in the context of the truncated receptor, and that minor autophosphorylation sites, such as Y992, may act as compensatory regulatory sties in the absence of the major EGF receptor autophosphorylation sites....

  9. Evidence for association of the cloned liver growth hormone receptor with a tyrosine kinase

    DEFF Research Database (Denmark)

    Wang, X; Uhler, M D; Billestrup, N;

    1992-01-01

    The ability of the cloned liver growth hormone (GH) receptor, when expressed in mammalian cell lines, to copurify with tyrosine kinase activity and be tyrosyl phosphorylated was examined. 125I-human growth hormone-GH receptor complexes isolated from COS-7 cells transiently expressing high levels...

  10. The Insect Neuropeptide PTTH Activates Receptor Tyrosine Kinase Torso to Initiate Metamorphosis

    DEFF Research Database (Denmark)

    Rewitz, Kim; Yamanaka, Naoki; Gilbert, Lawrence;

    2009-01-01

    that Torso, a receptor tyrosine kinase that regulates embryonic terminal cell fate in Drosophila, is the PTTH receptor. Trunk, the embryonic Torso ligand, is related to PTTH, and ectopic expression of PTTH in the embryo partially rescues trunk mutants. In larvae, torso is expressed specifically...

  11. Abelson tyrosine kinase links PDGFbeta receptor activation to cytoskeletal regulation of NMDA receptors in CA1 hippocampal neurons

    Directory of Open Access Journals (Sweden)

    Beazely Michael A

    2008-12-01

    Full Text Available Abstract Background We have previously demonstrated that PDGF receptor activation indirectly inhibits N-methyl-D-aspartate (NMDA currents by modifying the cytoskeleton. PDGF receptor ligand is also neuroprotective in hippocampal slices and cultured neurons. PDGF receptors are tyrosine kinases that control a variety of signal transduction pathways including those mediated by PLCγ. In fibroblasts Src and another non-receptor tyrosine kinase, Abelson kinase (Abl, control PDGF receptor regulation of cytoskeletal dynamics. The mechanism whereby PDGF receptor regulates cytoskeletal dynamics in central neurons remains poorly understood. Results Intracellular applications of active Abl, but not heat-inactivated Abl, decreased NMDA-evoked currents in isolated hippocampal neurons. This mimics the effects of PDGF receptor activation in these neurons. The Abl kinase inhibitor, STI571, blocked the inhibition of NMDA currents by Abl. We demonstrate that PDGF receptors can activate Abl kinase in hippocampal neurons via mechanisms similar to those observed previously in fibroblasts. Furthermore, PDGFβ receptor activation alters the subcellular localization of Abl. Abl kinase is linked to actin cytoskeletal dynamics in many systems. We show that the inhibition of NMDA receptor currents by Abl kinase is blocked by the inclusion of the Rho kinase inhibitor, Y-27632, and that activation of Abl correlates with an increase in ROCK tyrosine phosphorylation. Conclusion This study demonstrates that PDGFβ receptors act via an interaction with Abl kinase and Rho kinase to regulated cytoskeletal regulation of NMDA receptor channels in CA1 pyramidal neurons.

  12. Activated Cdc42-associated kinase Ack1 promotes prostate cancer progression via androgen receptor tyrosine phosphorylation

    OpenAIRE

    Mahajan, Nupam P.; Liu, Yuanbo; Majumder, Samarpan; Warren, Maria R.; Parker, Carol E.; Mohler, James L.; Earp, H. Shelton; Whang, Young E.

    2007-01-01

    Activation of the androgen receptor (AR) may play a role in androgen-independent progression of prostate cancer. Multiple mechanisms of AR activation, including stimulation by tyrosine kinases, have been postulated. We and others have recently shown involvement of activated Cdc42-associated tyrosine kinase Ack1 in advanced human prostate cancer. Here we provide the molecular basis for interplay between Ack1 and AR in prostate cancer cells. Activated Ack1 promoted androgen-independent growth o...

  13. Aberrant Mer receptor tyrosine kinase expression contributes to leukemogenesis in acute myeloid leukemia

    OpenAIRE

    Lee-Sherick, A B; Eisenman, K M; Sather, S; McGranahan, A; Armistead, P M; McGary, C S; Hunsucker, S A; Schlegel, J.; Martinson, H; Cannon, C; Keating, A K; Earp, H S; Liang, X; DeRyckere, D; Graham, D K

    2013-01-01

    Acute myeloid leukemia (AML) continues to be extremely difficult to treat successfully, and the unacceptably low overall survival rates mandate that we assess new potential therapies to ameliorate poor clinical response to conventional therapy. Abnormal tyrosine kinase activation in AML has been associated with poor prognosis and provides strategic targets for novel therapy development. We found that Mer receptor tyrosine kinase was over-expressed in a majority of pediatric (29/36, 80%) and a...

  14. Role of ErbB family receptor tyrosine kinases in intrahepatic cholangiocarcinoma

    OpenAIRE

    Sirica, Alphonse E.

    2008-01-01

    Aberrant expression and signaling of epidermal growth factor receptor (ErbB) family receptor tyrosine kinases, most notably that of ErbB2 and ErbB1, have been implicated in the molecular pathogenesis of intrahepatic cholangiocarcinoma. Constitutive overexpression of ErbB2 and/or ErbB1 in malignant cholangiocytes has raised interest in the possibility that agents which selectively target these receptors could potentially be effective in cholangiocarcinoma therapy. However, current experience w...

  15. Unlocking Doors without Keys: Activation of Src by Truncated C-terminal Intracellular Receptor Tyrosine Kinases Lacking Tyrosine Kinase Activity

    Directory of Open Access Journals (Sweden)

    Belén Mezquita

    2014-02-01

    Full Text Available One of the best examples of the renaissance of Src as an open door to cancer has been the demonstration that just five min of Src activation is sufficient for transformation and also for induction and maintenance of cancer stem cells [1]. Many tyrosine kinase receptors, through the binding of their ligands, become the keys that unlock the structure of Src and activate its oncogenic transduction pathways. Furthermore, intracellular isoforms of these receptors, devoid of any tyrosine kinase activity, still retain the ability to unlock Src. This has been shown with a truncated isoform of KIT (tr-KIT and a truncated isoform of VEGFR-1 (i21-VEGFR-1, which are intracellular and require no ligand binding, but are nonetheless able to activate Src and induce cell migration and invasion of cancer cells. Expression of the i21-VEGFR-1 is upregulated by the Notch signaling pathway and repressed by miR-200c and retinoic acid in breast cancer cells. Both Notch inhibitors and retinoic acid have been proposed as potential therapies for invasive breast cancer.

  16. Recruitment of epidermal growth factor receptors into coated pits requires their activated tyrosine kinase

    OpenAIRE

    1995-01-01

    EGF-receptor (EGF-R) tyrosine kinase is required for the down- regulation of activated EGF-R. However, controversy exists as to whether ligand-induced activation of the EGF-R tyrosine kinase is required for internalization or for lysosomal targeting. We have addressed this issue using a cell-free assay that selectively measures the recruitment of EGF-R into coated pits. Here we show that EGF bound to wild-type receptors is efficiently sequestered in coated pits. In contrast, sequestration of ...

  17. Receptor tyrosine kinases and schistosome reproduction: new targets for chemotherapy

    OpenAIRE

    Morel, Marion; Vanderstraete, Mathieu; Hahnel, Steffen; Grevelding, Christoph G.; Dissous, Colette

    2014-01-01

    Schistosome parasites still represent a serious public health concern and a major economic problem in developing countries. Pathology of schistosomiasis is mainly due to massive egg production by these parasites and to inflammatory responses raised against the eggs which are trapped in host tissues. Tyrosine kinases (TKs) are key molecules that control cell differentiation and proliferation and they already represent important targets in cancer therapy. During recent years, it has been shown ...

  18. SYK TYROSINE KINASE INVOLVEMENT IN COMPLEMENT RECEPTOR-MEDIATED SIGNALING LEADING TO AN OXIDATIVE BURST IN CHICKEN HETEROPHILS

    Science.gov (United States)

    We have previously reported the inhibition of Fc receptor-mediated degranulation in avian heterophils by the syk tyrosine kinase inhibitor piceatannol. The present studies investigated whether attachment of complement opsonized bacteria to complement receptors also involve the syk tyrosine kinase p...

  19. Biotinylation of Immunoglobulins

    International Nuclear Information System (INIS)

    The biotinylation of monoclonal antibodies (MAbs) represents a useful tool to prepare in house MAbs containing a number of biotin molecules, which do not compromise the MAb immunoreactivity, and can be used as a first step in the pretargeting approach, which foresees as a final step the intravenous injection of radiolabelled biotin

  20. Phosphorylation of insulin-like growth factor I receptor by insulin receptor tyrosine kinase in intact cultured skeletal muscle cells

    International Nuclear Information System (INIS)

    The interaction between insulin and insulin-like growth factor I (IGF I) receptors was examined by determining the ability of each receptor type to phosphorylate tyrosine residues on the other receptor in intact L6 skeletal muscle cells. This was made possible through a sequential immunoprecipitation method with two different antibodies that effectively separated the phosphorylated insulin and IGF I receptors. After incubation of intact L6 cells with various concentrations of insulin or IGF I in the presence of [32P]-orthophosphate, insulin receptors were precipitated with one of two human polyclonal anti-insulin receptor antibodies (B2 or B9). Phosphorylated IGF I receptors remained in solution and were subsequently precipitated by anti-phosphotyrosine antibodies. The identifies of the insulin and IGF I receptor β-subunits in the two immunoprecipitates were confirmed by binding affinity, by phosphopeptide mapping after trypsin digestion, and by the distinct patterns of expression of the two receptors during differentiation. Stimulated phosphorylation of the β-subunit of the insulin receptor correlated with the occupancy of the β-subunit of the insulin receptor by either insulin or IGF I as determined by affinity cross-linking. Similarly, stimulation of phosphorylation of the β-subunit of the IGF I receptor by IGF I correlated with IGF I receptor occupancy. In contrast, insulin stimulated phosphorylation of the β-subunit of the IGF I receptor at hormone concentrations that were associated with significant occupancy of the insulin receptor but negligible IGF I receptor occupancy. These findings indicate that the IGF I receptor can be a substrate for the hormone-activated insulin receptor tyrosine kinase activity in intact L6 skeletal muscle cells

  1. Phosphorylation of insulin-like growth factor I receptor by insulin receptor tyrosine kinase in intact cultured skeletal muscle cells

    Energy Technology Data Exchange (ETDEWEB)

    Beguinot, F.; Smith, R.J.; Kahn, C.R.; Maron, R.; Moses, A.C.; White, M.F.

    1988-05-03

    The interaction between insulin and insulin-like growth factor I (IGF I) receptors was examined by determining the ability of each receptor type to phosphorylate tyrosine residues on the other receptor in intact L6 skeletal muscle cells. This was made possible through a sequential immunoprecipitation method with two different antibodies that effectively separated the phosphorylated insulin and IGF I receptors. After incubation of intact L6 cells with various concentrations of insulin or IGF I in the presence of (/sup 32/P)-orthophosphate, insulin receptors were precipitated with one of two human polyclonal anti-insulin receptor antibodies (B2 or B9). Phosphorylated IGF I receptors remained in solution and were subsequently precipitated by anti-phosphotyrosine antibodies. The identifies of the insulin and IGF I receptor ..beta..-subunits in the two immunoprecipitates were confirmed by binding affinity, by phosphopeptide mapping after trypsin digestion, and by the distinct patterns of expression of the two receptors during differentiation. Stimulated phosphorylation of the ..beta..-subunit of the insulin receptor correlated with the occupancy of the ..beta..-subunit of the insulin receptor by either insulin or IGF I as determined by affinity cross-linking. Similarly, stimulation of phosphorylation of the ..beta..-subunit of the IGF I receptor by IGF I correlated with IGF I receptor occupancy. In contrast, insulin stimulated phosphorylation of the ..beta..-subunit of the IGF I receptor at hormone concentrations that were associated with significant occupancy of the insulin receptor but negligible IGF I receptor occupancy. These findings indicate that the IGF I receptor can be a substrate for the hormone-activated insulin receptor tyrosine kinase activity in intact L6 skeletal muscle cells.

  2. MET Receptor Tyrosine Kinase Controls Dendritic Complexity, Spine Morphogenesis, and Glutamatergic Synapse Maturation in the Hippocampus

    OpenAIRE

    Qiu, Shenfeng; Lu, Zhongming; Levitt, Pat

    2014-01-01

    The MET receptor tyrosine kinase (RTK), implicated in risk for autism spectrum disorder (ASD) and in functional and structural circuit integrity in humans, is a temporally and spatially regulated receptor enriched in dorsal pallial-derived structures during mouse forebrain development. Here we report that loss or gain of function of MET in vitro or in vivo leads to changes, opposite in nature, in dendritic complexity, spine morphogenesis, and the timing of glutamatergic synapse maturation ont...

  3. Construction and Stable Expression of a Truncated Human Receptor Tyrosine Kinase Ror1 (Ror1-ECD)

    OpenAIRE

    Forouzesh, Flora; Tabarian, Samira Shakeri; Emami, Shaghayegh; Tehrani, Mahmood-Jeddi; Hadavi, Reza; Rabbani, Hodjattallah

    2012-01-01

    Expression of receptor tyrosine kinase Ror1 in a wide variety of cancers has emerged as a new era focusing on targeting this receptor in cancer therapy. Our preliminary results indicate the presence of a truncated transcript of Ror1 in tumor cells. The truncated Ror1 encompasses extracellular and transmembrane domains, lacking catalytic kinase domain (Ror1-ECD). As enzyme activity is highly dependent on the catalytic domain, we were wondering how this transcript and its encoded protein could ...

  4. Combined therapeutic potential of nuclear receptors with receptor tyrosine kinase inhibitors in lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Wairagu, Peninah M. [Department of Biochemistry, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do 220-701 (Korea, Republic of); Institute of Lifestyle Medicine, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do 220-701 (Korea, Republic of); Nuclear Receptor Research Consortium, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do 220-701 (Korea, Republic of); Park, Kwang Hwa [Department of Pathology, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do 220-701 (Korea, Republic of); Kim, Jihye [Department of Biochemistry, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do 220-701 (Korea, Republic of); Institute of Lifestyle Medicine, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do 220-701 (Korea, Republic of); Nuclear Receptor Research Consortium, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do 220-701 (Korea, Republic of); Choi, Jong-Whan; Kim, Hyun-Won; Yeh, Byung-Il [Department of Biochemistry, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do 220-701 (Korea, Republic of); Jung, Soon-Hee [Department of Pathology, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do 220-701 (Korea, Republic of); Yong, Suk-Joong [Department of Internal Medicine, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do 220-701 (Korea, Republic of); Jeong, Yangsik, E-mail: yjeong@yonsei.ac.kr [Department of Biochemistry, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do 220-701 (Korea, Republic of); Institute of Lifestyle Medicine, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do 220-701 (Korea, Republic of); Nuclear Receptor Research Consortium, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do 220-701 (Korea, Republic of)

    2014-05-09

    Highlights: • The 48 NR genes and 48 biological anti-cancer targets are profiled in paired-cells. • Growth inhibition by NR ligands or TKIs is target receptor level-dependent. • T0901317 with gefitinib/PHA665752 shows additive growth inhibition in lung cells. - Abstract: Cancer heterogeneity is a big hurdle in achieving complete cancer treatment, which has led to the emergence of combinational therapy. In this study, we investigated the potential use of nuclear receptor (NR) ligands for combinational therapy with other anti-cancer drugs. We first profiled all 48 NRs and 48 biological anti-cancer targets in four pairs of lung cell lines, where each pair was obtained from the same patient. Two sets of cell lines were normal and the corresponding tumor cell lines while the other two sets consisted of primary versus metastatic tumor cell lines. Analysis of the expression profile revealed 11 NRs and 15 cancer targets from the two pairs of normal versus tumor cell lines, and 9 NRs and 9 cancer targets from the primary versus metastatic tumor cell lines had distinct expression patterns in each category. Finally, the evaluation of nuclear receptor ligand T0901317 for liver X receptor (LXR) demonstrated its combined therapeutic potential with tyrosine kinase inhibitors. The combined treatment of cMET inhibitor PHA665752 or EGFR inhibitor gefitinib with T0901317 showed additive growth inhibition in both H2073 and H1993 cells. Mechanistically, the combined treatment suppressed cell cycle progression by inhibiting cyclinD1 and cyclinB expression. Taken together, this study provides insight into the potential use of NR ligands in combined therapeutics with other biological anti-cancer drugs.

  5. Combined therapeutic potential of nuclear receptors with receptor tyrosine kinase inhibitors in lung cancer

    International Nuclear Information System (INIS)

    Highlights: • The 48 NR genes and 48 biological anti-cancer targets are profiled in paired-cells. • Growth inhibition by NR ligands or TKIs is target receptor level-dependent. • T0901317 with gefitinib/PHA665752 shows additive growth inhibition in lung cells. - Abstract: Cancer heterogeneity is a big hurdle in achieving complete cancer treatment, which has led to the emergence of combinational therapy. In this study, we investigated the potential use of nuclear receptor (NR) ligands for combinational therapy with other anti-cancer drugs. We first profiled all 48 NRs and 48 biological anti-cancer targets in four pairs of lung cell lines, where each pair was obtained from the same patient. Two sets of cell lines were normal and the corresponding tumor cell lines while the other two sets consisted of primary versus metastatic tumor cell lines. Analysis of the expression profile revealed 11 NRs and 15 cancer targets from the two pairs of normal versus tumor cell lines, and 9 NRs and 9 cancer targets from the primary versus metastatic tumor cell lines had distinct expression patterns in each category. Finally, the evaluation of nuclear receptor ligand T0901317 for liver X receptor (LXR) demonstrated its combined therapeutic potential with tyrosine kinase inhibitors. The combined treatment of cMET inhibitor PHA665752 or EGFR inhibitor gefitinib with T0901317 showed additive growth inhibition in both H2073 and H1993 cells. Mechanistically, the combined treatment suppressed cell cycle progression by inhibiting cyclinD1 and cyclinB expression. Taken together, this study provides insight into the potential use of NR ligands in combined therapeutics with other biological anti-cancer drugs

  6. Requirement of tyrosine residues 333 and 338 of the growth hormone (GH) receptor for selected GH-stimulated function

    DEFF Research Database (Denmark)

    Lobie, P E; Allevato, G; Norstedt, G;

    1995-01-01

    We have examined the involvement of tyrosine residues 333 and 338 of the growth hormone (GH) receptor in the cellular response to GH. Stable Chinese hamster ovary (CHO) cell clones expressing a receptor with tyrosine residues at position 333 and 338 of the receptor substituted for phenylalanine (...... acetyltransferase cDNA expression driven by the GH-responsive region of the SPI 2.1 gene) was not affected by Y333F,Y338F substitution. Thus we provide the first experimental evidence that specific tyrosine residues of the GH receptor are required for selected cellular responses to GH....

  7. Intracellular Ca2+ stores modulate SOCCs and NMDA receptors via tyrosine kinases in rat hippocampal neurons.

    Science.gov (United States)

    Koss, David J; Riedel, Gernot; Platt, Bettina

    2009-07-01

    The regulation of intracellular Ca(2+) signalling by phosphorylation processes remains poorly defined, particularly with regards to tyrosine phosphorylation. Evidence from non-excitable cells implicates tyrosine phosphorylation in the activation of so-called store-operated Ca(2+) channels (SOCCs), but their involvement in neuronal Ca(2+) signalling is still elusive. In the present study, we determined the role of protein tyrosine kinases (PTKs) and tyrosine phosphatases (PTPs) in the coupling between intracellular Ca(2+) stores and SOCCs in neonatal rat hippocampal neurons by Fura-2 Ca(2+) imaging. An early Ca(2+) response from intracellular stores was triggered with thapsigargin, and followed by a secondary plasma membrane Ca(2+) response. This phase was blocked by the non-specific Ca(2+) channel blocker NiCl and the SOCC blocker, 2-aminoethoxydiphenyl borate (2-APB). Interestingly, two structurally distinct PTK inhibitors, genistein and AG126, also inhibited this secondary response. Application of the PTP inhibitor sodium orthovanadate (OV) also activated a sustained and tyrosine kinase dependent Ca(2+) response, blocked by NiCl and 2-APB. In addition, OV resulted in a Ca(2+) store dependent enhancement of NMDA responses, corresponding to, and occluding the signalling pathway for group I metabotropic glutamate receptors (mGluRs). This study provides first evidence for tyrosine based phospho-regulation of SOCCs and NMDA signalling in neurons. PMID:19423160

  8. A bacterial tyrosine phosphatase inhibits plant pattern recognition receptor activation

    Science.gov (United States)

    Perception of pathogen-associated molecular patterns (PAMPs) by surface-localised pattern-recognition receptors (PRRs) is a key component of plant innate immunity. Most known plant PRRs are receptor kinases and initiation of PAMP-triggered immunity (PTI) signalling requires phosphorylation of the PR...

  9. Application of computational approaches to study signalling networks of nuclear and Tyrosine kinase receptors

    Directory of Open Access Journals (Sweden)

    Rebaï Ahmed

    2010-10-01

    Full Text Available Abstract Background Nuclear receptors (NRs and Receptor tyrosine kinases (RTKs are essential proteins in many cellular processes and sequence variations in their genes have been reported to be involved in many diseases including cancer. Although crosstalk between RTK and NR signalling and their contribution to the development of endocrine regulated cancers have been areas of intense investigation, the direct coupling of their signalling pathways remains elusive. In our understanding of the role and function of nuclear receptors on the cell membrane the interactions between nuclear receptors and tyrosine kinase receptors deserve further attention. Results We constructed a human signalling network containing nuclear receptors and tyrosine kinase receptors that identified a network topology involving eleven highly connected hubs. We further developed an integrated knowledge database, denominated NR-RTK database dedicated to human RTKs and NRs and their vertebrate orthologs and their interactions. These interactions were inferred using computational tools and those supported by literature evidence are indicated. NR-RTK database contains links to other relevant resources and includes data on receptor ligands. It aims to provide a comprehensive interaction map that identifies complex dynamics and potential crosstalk involved. Availability: NR-RTK database is accessible at http://www.bioinfo-cbs.org/NR-RTK/ Conclusions We infer that the NR-RTK interaction network is scale-free topology. We also uncovered the key receptors mediating the signal transduction between these two types of receptors. Furthermore, NR-RTK database is expected to be useful for researchers working on various aspects of the molecular basis of signal transduction by RTKs and NRs. Reviewers This article was reviewed by Professor Paul Harrison (nominated by Dr. Mark Gerstein, Dr. Arcady Mushegian and Dr. Anthony Almudevar.

  10. Allosteric inhibition of SHP2 phosphatase inhibits cancers driven by receptor tyrosine kinases.

    Science.gov (United States)

    Chen, Ying-Nan P; LaMarche, Matthew J; Chan, Ho Man; Fekkes, Peter; Garcia-Fortanet, Jorge; Acker, Michael G; Antonakos, Brandon; Chen, Christine Hiu-Tung; Chen, Zhouliang; Cooke, Vesselina G; Dobson, Jason R; Deng, Zhan; Fei, Feng; Firestone, Brant; Fodor, Michelle; Fridrich, Cary; Gao, Hui; Grunenfelder, Denise; Hao, Huai-Xiang; Jacob, Jaison; Ho, Samuel; Hsiao, Kathy; Kang, Zhao B; Karki, Rajesh; Kato, Mitsunori; Larrow, Jay; La Bonte, Laura R; Lenoir, Francois; Liu, Gang; Liu, Shumei; Majumdar, Dyuti; Meyer, Matthew J; Palermo, Mark; Perez, Lawrence; Pu, Minying; Price, Edmund; Quinn, Christopher; Shakya, Subarna; Shultz, Michael D; Slisz, Joanna; Venkatesan, Kavitha; Wang, Ping; Warmuth, Markus; Williams, Sarah; Yang, Guizhi; Yuan, Jing; Zhang, Ji-Hu; Zhu, Ping; Ramsey, Timothy; Keen, Nicholas J; Sellers, William R; Stams, Travis; Fortin, Pascal D

    2016-07-01

    The non-receptor protein tyrosine phosphatase SHP2, encoded by PTPN11, has an important role in signal transduction downstream of growth factor receptor signalling and was the first reported oncogenic tyrosine phosphatase. Activating mutations of SHP2 have been associated with developmental pathologies such as Noonan syndrome and are found in multiple cancer types, including leukaemia, lung and breast cancer and neuroblastoma. SHP2 is ubiquitously expressed and regulates cell survival and proliferation primarily through activation of the RAS–ERK signalling pathway. It is also a key mediator of the programmed cell death 1 (PD-1) and B- and T-lymphocyte attenuator (BTLA) immune checkpoint pathways. Reduction of SHP2 activity suppresses tumour cell growth and is a potential target of cancer therapy. Here we report the discovery of a highly potent (IC50 = 0.071 μM), selective and orally bioavailable small-molecule SHP2 inhibitor, SHP099, that stabilizes SHP2 in an auto-inhibited conformation. SHP099 concurrently binds to the interface of the N-terminal SH2, C-terminal SH2, and protein tyrosine phosphatase domains, thus inhibiting SHP2 activity through an allosteric mechanism. SHP099 suppresses RAS–ERK signalling to inhibit the proliferation of receptor-tyrosine-kinase-driven human cancer cells in vitro and is efficacious in mouse tumour xenograft models. Together, these data demonstrate that pharmacological inhibition of SHP2 is a valid therapeutic approach for the treatment of cancers. PMID:27362227

  11. Inhibition of receptor tyrosine kinase signalling by small molecule agonist of T-cell protein tyrosine phosphatase

    International Nuclear Information System (INIS)

    T-cell protein tyrosine phosphatase (TCPTP/TC45) is a ubiquitously expressed intra-cellular non-receptor protein tyrosine phosphatase involved in the negative regulation of several cancer relevant cellular signalling pathways. We have previously shown that interaction between the α-cytoplasmic tail of α1β1 integrin and TCPTP activates TCPTP by disrupting an inhibitory intra-molecular bond in TCPTP. Thus, inhibition of the regulatory interaction in TCPTP is a desirable strategy for TCPTP activation and attenuation of oncogenic RTK signalling. However, this is challenging with low molecular weight compounds. We developed a high-throughput compatible assay to analyse activity of recombinant TCPTP in vitro. Using this assay we have screened 64280 small molecules to identify novel agonists for TCPTP. Dose-dependent response to TCPTP agonist was performed using the in vitro assay. Inhibition effects and specificity of TCPTP agonists were evaluated using TCPTP expressing and null mouse embryonic fibroblasts. Western blot analysis was used to evaluate attenuation of PDGFRβ and EGFR phosphorylation. Inhibition of VEGF signalling was analysed with VEGF-induced endothelial cell sprouting assays. From the screen we identified six TCPTP agonists. Two compounds competed with α1-cytoplasmic domain for binding to TCPTP, suggesting that they activate TCPTP similar to α1-cyt by disrupting the intra-molecular bond in TCPTP. Importantly, one of the compounds (spermidine) displayed specificity towards TCPTP in cells, since TCPTP -/- cells were 43-fold more resistant to the compound than TCPTP expressing cells. This compound attenuates PDGFRβ and VEGFR2 signalling in cells in a TCPTP-dependent manner and functions as a negative regulator of EGFR phosphorylation in cancer cells. In this study we showed that small molecules mimicking TCPTP-α1 interaction can be used as TCPTP agonists. These data provide the first proof-of-concept description of the use of high-throughput screening

  12. Profiling epidermal growth factor receptor and heregulin receptor 3 heteromerization using receptor tyrosine kinase heteromer investigation technology.

    Directory of Open Access Journals (Sweden)

    Mohammed Akli Ayoub

    Full Text Available Heteromerization can play an important role in regulating the activation and/or signal transduction of most forms of receptors, including receptor tyrosine kinases (RTKs. The study of receptor heteromerization has evolved extensively with the emergence of resonance energy transfer based approaches such as bioluminescence resonance energy transfer (BRET. Here, we report an adaptation of our Receptor-Heteromer Investigation Technology (Receptor-HIT that has recently been published as the G protein-coupled receptor (GPCR Heteromer Identification Technology (GPCR-HIT. We now demonstrate the utility of this approach for investigating RTK heteromerization by examining the functional interaction between the epidermal growth factor (EGF receptor (EGFR; also known as erbB1/HER1 and heregulin (HRG receptor 3 (HER3; also known as erbB3 in live HEK293FT cells using recruitment of growth factor receptor-bound protein 2 (Grb2 to the activated receptors. We found that EGFR and HER3 heteromerize specifically as demonstrated by HRG inducing a BRET signal between EGFR/Rluc8 and Grb2/Venus only when HER3 was co-expressed. Similarly, EGF stimulation promoted a specific BRET signal between HER3/Rluc8 and Grb2/Venus only when EGFR was co-expressed. Both EGF and HRG effects on Grb2 interaction are dose-dependent, and specifically blocked by EGFR inhibitor AG-1478. Furthermore, truncation of HER3 to remove the putative Grb2 binding sites appears to abolish EGF-induced Grb2 recruitment to the EGFR-HER3 heteromer. Our results support the concept that EGFR interacts with Grb2 in both constitutive and EGF-dependent manners and this interaction is independent of HER3 co-expression. In contrast, HER3-Grb2 interaction requires the heteromerization between EGFR and HER3. These findings clearly indicate the importance of EGFR-HER3 heteromerization in HER3-mediated Grb2-dependent signaling pathways and supports the central role of HER3 in the diversity and regulation of HER

  13. Family of receptor-linked protein tyrosine phosphatases in humans and Drosophila

    International Nuclear Information System (INIS)

    To understand the regulation of cell proliferation by tyrosine phosphorylation, characterization of protein tyrosine phosphatases is essential. The human genes LCA (leukocyte common antigen) and LAR encode putative receptor-linked PTPases. By using consensus sequence probes, two additional receptor-linked PTPase genes, DLAR and DPTP, were isolated from Drosophila melanogaster. The extra-cellular segments of both DLAR and DPTP are composed of multiple immunoglobulin-like domains and fibronectin type III-like domains. The cytoplasmic region of DLAR and DPTP, as well as human LCA and LAR, are composed of two tandemly repeated PTPase domains. PTPase activities of immunoprecipitated LCA and LAR were demonstrated by measuring the release of phosphate from a 32P-labeled [Tyr(P)]peptide. Furthermore, the cytoplasmic domains of LCA, LAR, DLAR, and DPTP, expressed in Escherichia coli, have PTPase activity. Site-directed mutagenesis showed that a conserved cysteine residue is essential for PTPase activity

  14. Structural Mimicry of A-Loop Tyrosine Phosphorylation by a Pathogenic FGF Receptor 3 Mutation

    OpenAIRE

    Huang, Zhifeng; Chen, Huaibin; Blais, Steven; Neubert, Thomas A.; Li, Xiaokun; Mohammadi, Moosa

    2013-01-01

    The K650E gain-of-function mutation in the tyrosine kinase domain of FGF receptor 3 (FGFR3) causes Thanatophoric Dysplasia type II, a neonatal lethal congenital dwarfism syndrome, and when acquired somatically, it contributes to carcinogenesis. In this report, we determine the crystal structure of the FGFR3 kinase domain harboring this pathogenic mutation and show that the mutation introduces a network of intramolecular hydrogen bonds to stabilize the active-state conformation. In the crystal...

  15. Diabetes and Microvascular Physio-Pathology: Role of Epidermal Growth Factor Receptor Tyrosine Kinase

    OpenAIRE

    Matrougui, Khalid

    2010-01-01

    Type 2 diabetes is responsible for the increased prevalence of ischemic heart disease, generally related to coronary artery disease, which is associated with increased morbidity and death in diabetic patients. Epidermal growth factor receptor (EGFR) tyrosine kinase, one of the many factors involved in cell growth and migration has been shown to be key element in the development of microvessel myogenic tone. In a recent study, we have shown that microvascular dysfunction in type 2 diabetes is ...

  16. Protein tyrosine phosphatase non-receptor type 2 and inflammatory bowel disease

    OpenAIRE

    Spalinger, Marianne R.; MCCOLE, DECLAN F.; Rogler, Gerhard; Scharl, Michael

    2016-01-01

    Genome wide association studies have associated single nucleotide polymorphisms within the gene locus encoding protein tyrosine phosphatase non-receptor type 2 (PTPN2) with the onset of inflammatory bowel disease (IBD) and other inflammatory disorders. Expression of PTPN2 is enhanced in actively inflamed intestinal tissue featuring a marked up-regulation in intestinal epithelial cells. PTPN2 deficient mice suffer from severe intestinal and systemic inflammation and display aberrant innate and...

  17. Tyrosine Kinase Domain Gene Polymorphism of Epidermal Growth Factor Receptor in Gastric Cancer in Northern Iran

    Directory of Open Access Journals (Sweden)

    Jeivad F

    2012-01-01

    Full Text Available Background: Gastric cancer is one of the most common diseases of digestive system with a low 5-year survival rate and metastasis is the main cause of death. Multi-factors, such as changes in molecular pathways and deregulation of cells are involved in the disease development. Epidermal growth factor receptor pathway (EGFR which is associated with cell proliferation and survival can influence cancer development. EGFR function is governed by its genetic polymorphism; thus, we aimed to study the tyrosine kinase domain gene mutations of the receptor in patients with gastric cancer.Methods : In this experimental study, 123 subjects (83 patients with gastric cancer and 40 normal subjects were investigated in north of Iran for EGFR gene polymorphisms during 1 year. Genomic DNA was extracted by DNA extraction kit according to the manufacture's protocol. Polymerase chain reaction single-stranded conformation polymorphism (PCR-SSCP and silver staining were performed for investigating EGFR gene polymorphisms. Results : The participants included 72 men and 44 women. Gene polymorphism in exon 18 was present in 10% of the study population but SSCP pattern in exon 19 did not show different migrate bands neither in patients nor in normal subjects.Conclusion: It seems that screening for tyrosine kinas gene polymorphism of epidermal growth factor receptor in patients with gastric cancer and use of tyrosine kinas inhibitors could be useful in the prevention of disease progress and improvement of treatment process for a better quality of life in these patients.

  18. Endocytosis of the ASGP receptor H1 is reduced by mutation of tyrosine-5 but still occurs via coated pits

    OpenAIRE

    Fuhrer, C; Geffen, I; Spiess, M.

    1991-01-01

    The clustering of plasma membrane receptors in clathrin-coated pits depends on determinants within their cytoplasmic domains. In several cases, individual tyrosine residues were shown to be necessary for rapid internalization. We have mutated the single tyrosine at position 5 in the cytoplasmic domain of the major subunit H1 of the asialoglycoprotein receptor to alanine. Expressed in fibroblasts cells, the mutant protein was accumulated in the plasma membrane, and its rate of internalization ...

  19. Role of receptor tyrosine kinases in gastric cancer: New targets for a selective therapy

    Institute of Scientific and Technical Information of China (English)

    JC Becker; C Müller-Tidow; H Serve; W Domschke; T Pohle

    2006-01-01

    Receptor tyrosine kinases (RTKs) such as the epidermal growth factor receptor family participate in several steps of tumor formation including proliferation and metastatic spread. Several known RTKs are upregulated in gastric cancer being prime targets of a tailored therapy. Only preliminary data exist, however, on the use of the currently clinically available drugs such as trastuzumab,cetuximab, bevacizumab, gefitinib, erlotinib, and imatinib in the setting of gastric cancer. Preclinical data suggest a potential benefit of their use, especially in combination with "conventional" cytostatic therapy. This review summarizes the current knowledge about their use in cancer therapy as well as new approaches and drugs to optimize treatment success.

  20. Inhibition of receptor tyrosine kinase signalling by small molecule agonist of T-cell protein tyrosine phosphatase

    Directory of Open Access Journals (Sweden)

    Tähtinen Siri

    2010-01-01

    Full Text Available Abstract Background T-cell protein tyrosine phosphatase (TCPTP/TC45 is a ubiquitously expressed intra-cellular non-receptor protein tyrosine phosphatase involved in the negative regulation of several cancer relevant cellular signalling pathways. We have previously shown that interaction between the α-cytoplasmic tail of α1β1 integrin and TCPTP activates TCPTP by disrupting an inhibitory intra-molecular bond in TCPTP. Thus, inhibition of the regulatory interaction in TCPTP is a desirable strategy for TCPTP activation and attenuation of oncogenic RTK signalling. However, this is challenging with low molecular weight compounds. Methods We developed a high-throughput compatible assay to analyse activity of recombinant TCPTP in vitro. Using this assay we have screened 64280 small molecules to identify novel agonists for TCPTP. Dose-dependent response to TCPTP agonist was performed using the in vitro assay. Inhibition effects and specificity of TCPTP agonists were evaluated using TCPTP expressing and null mouse embryonic fibroblasts. Western blot analysis was used to evaluate attenuation of PDGFRβ and EGFR phosphorylation. Inhibition of VEGF signalling was analysed with VEGF-induced endothelial cell sprouting assays. Results From the screen we identified six TCPTP agonists. Two compounds competed with α1-cytoplasmic domain for binding to TCPTP, suggesting that they activate TCPTP similar to α1-cyt by disrupting the intra-molecular bond in TCPTP. Importantly, one of the compounds (spermidine displayed specificity towards TCPTP in cells, since TCPTP -/- cells were 43-fold more resistant to the compound than TCPTP expressing cells. This compound attenuates PDGFRβ and VEGFR2 signalling in cells in a TCPTP-dependent manner and functions as a negative regulator of EGFR phosphorylation in cancer cells. Conclusions In this study we showed that small molecules mimicking TCPTP-α1 interaction can be used as TCPTP agonists. These data provide the first

  1. Characterization of a novel Eph receptor tyrosine kinase, EphA10, expressed in testis.

    Science.gov (United States)

    Aasheim, Hans-Christian; Patzke, Sebastian; Hjorthaug, Hanne Sagsveen; Finne, Eivind Farmen

    2005-05-25

    In mammals, 14 members of the Eph receptor tyrosine kinase family have been described so far. Here we present a not yet described member of this family denoted EphA10. We report the identification of three putative EphA10 isoforms: one soluble and two transmembrane isoforms. One of the latter isoforms lacked the sterile alpha motif commonly found in Eph receptors. The gene encoding EphA10 is located on chromosome 1p34 and expression studies show that EphA10 mRNA is mainly expressed in testis. Binding studies to ephrin ligands suggests that this receptor belongs to the EphA subclass of Eph receptors binding mainly to ephrin-A ligands. PMID:15777695

  2. Complexes of Streptavidin-Fused Antigens with Biotinylated Antibodies Targeting Receptors on Dendritic Cell Surface: A Novel Tool for Induction of Specific T-Cell Immune Responses

    Czech Academy of Sciences Publication Activity Database

    Staněk, Ondřej; Linhartová, Irena; Majlessi, L.; Leclerc, C.; Šebo, Peter

    2012-01-01

    Roč. 51, č. 3 (2012), s. 221-232. ISSN 1073-6085 R&D Projects: GA AV ČR KAN200520702; GA ČR GA310/08/0447; GA MŠk 2B06161 Institutional research plan: CEZ:AV0Z50200510 Keywords : Streptavidin * Antigen delivery * Biotinylated antibody Subject RIV: EE - Microbiology, Virology Impact factor: 2.262, year: 2012

  3. Replacement of insulin receptor tyrosine residues 1162 and 1163 does not alter the mitogenic effect of the hormone

    International Nuclear Information System (INIS)

    Chinese hamster ovary transfectants that express insulin receptors in which tyrosine residues 1162 and 1163 were replaced by phenylalanine exhibit a total inhibition of the insulin-mediated tyrosine kinase activity toward exogenous substrates; this latter activity is associated with total inhibition of the hypersensitivity reported for insulin in promoting 2-deoxyglucose uptake. The authors now present evidence that the twin tyrosines also control the insulin-mediated stimulation of glycogen synthesis. Surprisingly, this type of Chinese hamster ovary transfectant is as hypersensitive to insulin for its mitogenic effect as are Chinese hamster ovary cells expressing many intact insulin receptors. Such data suggest that (i) the insulin mitogenic effect routes through a different pathway than insulin uses to activate the transport and metabolism of glucose and (ii) the mitogenic effect of insulin is not controlled by the twin tyrosines. At the molecular level, the solubilized mutated receptor has not insulin-dependent tyrosine kinase activity, whereas this receptor displays measurable insulin-stimulated phosphorylation of its β subunit in 32P-labeled cells. The authors therefore propose that the autocatalytic phosphorylating activity of the receptor reports a cryptic tyrosine kinase activity that cannot be visualized by the use of classical exogenous substrates

  4. Crystal structure of the Sema-PSI extracellular domain of human RON receptor tyrosine kinase.

    Directory of Open Access Journals (Sweden)

    Kinlin L Chao

    Full Text Available Human RON (Recepteur d'Origine Nantais receptor tyrosine kinase is a cell surface receptor for Macrophage Stimulating Protein (MSP. RON mediates signal transduction pathways that regulate cell adhesion, invasion, motility and apoptosis processes. Elevated levels of RON and its alternatively spliced variants are implicated in the progression and metastasis of tumor cells. The binding of MSP α/β heterodimer to the extracellular region of RON receptor induces receptor dimerization and activation by autophosphorylation of the intracellular kinase domains. The ectodomain of RON, containing the ligand recognition and dimerization domains, is composed of a semaphorin (Sema, Plexins-Semaphorins-Integrins domain (PSI, and four Immunoglobulins-Plexins-Transcription factor (IPT domains. High affinity association between MSP and RON is mediated by the interaction between MSP β-chain and RON Sema, although RON activation requires intact RON and MSP proteins. Here, we report the structure of RON Sema-PSI domains at 1.85 Å resolution. RON Sema domain adopts a seven-bladed β-propeller fold, followed by disulfide bond rich, cysteine-knot PSI motif. Comparison with the homologous Met receptor tyrosine kinase reveals that RON Sema-PSI contains distinguishing secondary structural features. These define the receptors' exclusive selectivity towards their respective ligands, RON for MSP and Met for HGF. The RON Sema-PSI crystal packing generates a homodimer with interface formed by the Sema domain. Mapping of the dimer interface using the RON homology to Met, MSP homology to Hepatocyte Growth Factor (HGF, and the structure of the Met/HGF complex shows the dimer interface overlapping with the putative MSPβ binding site. The crystallographically determined RON Sema-PSI homodimer may represent the dimer assembly that occurs during ligand-independent receptor activation and/or the inhibition of the constitutive activity of RONΔ160 splice variant by the soluble RON

  5. Role of Cbl-associated protein/ponsin in receptor tyrosine kinase signaling and cell adhesion

    Directory of Open Access Journals (Sweden)

    Ritva Tikkanen

    2012-10-01

    Full Text Available The Cbl-associated protein/ponsin (CAP is an adaptor protein that contains a so-called Sorbin homology (SoHo domain and three Src homology 3 (SH3 domains which are engaged in diverse protein-protein interactions. CAP has been shown to function in the regulation of the actin cytoskeleton and cell adhesion and to be involved in the differentiation of muscle cells and adipocytes. In addition, it participates in signaling pathways through several receptor tyrosine kinases such as insulin and neurotrophin receptors. In the last couple of years, several studies have shed light on the details of these processes and identified novel interaction partners of CAP. In this review, we summarize these recent findings and provide an overview on the function of CAP especially in cell adhesion and membrane receptor signaling.

  6. Separate domains of the insulin receptor contain sites of autophosphorylation and tyrosine kinase activity

    International Nuclear Information System (INIS)

    The authors have studied the structure and function of the solubilized insulin receptor before and after partial proteolytic digestion to define domains in the β-subunit that undergo autophosphorylation and contain the tyrosine kinase activity. Wheat germ agglutinin purified insulin receptor from Fao cells was digested briefly at 220C with low concentrations of trypsin, staphylococcal V8 protease, or elastase. Autophosphorylation of the β-subunit was carried out before and after digestion, and the [32P]phosphoproteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, detected by autoradiography, and analyzed by tryptic peptide mapping by use of reverse-phase high-performance liquid chromatography. The 85-kDa fragment was not immunoprecipitated by an antibody directed against the C-terminal domain of the β-subunit (αPep-1), indicating that this region of the receptor was lost. The 85-kDa fragment contained about half of the [32P]phosphate originally found in the β-subunit, and tryptic peptide mapping showed that two major tryptic phosphopeptides (previously called pY2 and pY3) were removed. Three other tryptic phosphopeptides (pY1, pY1a, and pY4) were found in the 85- and 70-kDa fragments. To determined the structural requirements for kinase activity, the insulin receptor was subjected to tryptic digestion for 30 s-30 min, such that the receptor was composed exclusively of 85- and 70-kDa fragments of the β-subunit. The 85-kDa fragment exhibited autophosphorylation at pY1, pY1a, and pY4. Both the 85- and 70-kDa fragments phosphorylated tyrosine residues in a synthetic decapeptide that has the sequence of the C-terminal domain of the β-subunit of human insulin rare in the receptor

  7. Functional characterization of autophosphorylation sites of the activated insulin receptor-tyrosine kinase

    International Nuclear Information System (INIS)

    Insulin receptor, solubilized from 3T3-L1 cellular membranes and then purified, was autophosphorylated with [γ-32P]ATP in the absence or presence of insulin. Specific phosphopeptides generated by trypsin digestion of the 32P-labeled β-subunit were identified and separated by reverse phase HPLC. In the absence of insulin, radioactivity of the phosphopeptides is evenly distributed among four major peaks designated as sites I, II, III and IV, according to their order of elution. This pattern is maintained for at least the first 30 min of autophosphorylation. When the reaction is carried out in the presence of insulin, > 50% of the total 32P radioactivity is found in site I and the rate of 32P incorporation into this site is markedly higher than into sites II, III and IV. Maximal activation of tyrosine kinase activity, as estimated by substrate phosphorylation, is coincident with the nearly complete phosphorylation of site I. Delayed activation of previously autophosphorylated receptor by insulin, but not by EGF or IGF-I, produced a similar pattern where phosphorylated site I predominates. These observations indicate that one major insulin-regulated autophosphorylation site in the β-subunit is responsible for activation of the insulin receptor tyrosine kinase. The isolation of this phosphopeptide on a preparative scale and its characterization are now in progress

  8. Functional characterization of autophosphorylation sites of the activated insulin receptor-tyrosine kinase

    Energy Technology Data Exchange (ETDEWEB)

    Flores-Riveros, J.R.; Lane, M.D.

    1987-05-01

    Insulin receptor, solubilized from 3T3-L1 cellular membranes and then purified, was autophosphorylated with (..gamma..-/sup 32/P)ATP in the absence or presence of insulin. Specific phosphopeptides generated by trypsin digestion of the /sup 32/P-labeled ..beta..-subunit were identified and separated by reverse phase HPLC. In the absence of insulin, radioactivity of the phosphopeptides is evenly distributed among four major peaks designated as sites I, II, III and IV, according to their order of elution. This pattern is maintained for at least the first 30 min of autophosphorylation. When the reaction is carried out in the presence of insulin, > 50% of the total /sup 32/P radioactivity is found in site I and the rate of /sup 32/P incorporation into this site is markedly higher than into sites II, III and IV. Maximal activation of tyrosine kinase activity, as estimated by substrate phosphorylation, is coincident with the nearly complete phosphorylation of site I. Delayed activation of previously autophosphorylated receptor by insulin, but not by EGF or IGF-I, produced a similar pattern where phosphorylated site I predominates. These observations indicate that one major insulin-regulated autophosphorylation site in the ..beta..-subunit is responsible for activation of the insulin receptor tyrosine kinase. The isolation of this phosphopeptide on a preparative scale and its characterization are now in progress.

  9. Syndecan-2 is a novel ligand for the protein tyrosine phosphatase receptor CD148

    DEFF Research Database (Denmark)

    Whiteford, James R; Xian, Xiaojie; Chaussade, Claire; Vanhaesebroeck, Bart; Nourshargh, Sussan; Couchman, John R

    2011-01-01

    Syndecan-2 is a heparan sulfate proteoglycan that has a cell adhesion regulatory domain contained within its extracellular core protein. Cell adhesion to the syndecan-2 extracellular domain (S2ED) is ß1 integrin dependent; however, syndecan-2 is not an integrin ligand. Here the protein tyrosine...... phosphatase receptor CD148 is shown to be a key intermediary in cell adhesion to S2ED, with downstream ß1 integrin-mediated adhesion and cytoskeletal organization. We show that S2ED is a novel ligand for CD148 and identify the region proximal to the transmembrane domain of syndecan-2 as the site of...

  10. Dialkoxyquinazolines: Screening Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors for Potential Tumor Imaging Probes

    International Nuclear Information System (INIS)

    The epidermal growth factor receptor (EGFR), a long-standing drug development target, is also a desirable target for imaging. Sixteen dialkoxyquinazoline analogs, suitable for labeling with positron-emitting isotopes, have been synthesized and evaluated in a battery of in vitro assays to ascertain their chemical and biological properties. These characteristics provided the basis for the adoption of a selection schema to identify lead molecules for labeling and in vivo evaluation. A newEGFR tyrosine kinase radiometric binding assay revealed that all of the compounds possessed suitable affinity (IC50 = 0.4 - 51 nM) for the EGFR tyrosine kinase. All of the analogs inhibited ligand-induced EGFR tyrosine phosphorylation (IC50 = 0.8 - 20 nM). The HPLC-estimated octanol/water partition coefficients ranged from 2.0-5.5. Four compounds,4-(2'-fluoroanilino)- and 4-(3'-fluoroanilino)-6,7-diethoxyquinazoline as well as 4-(3'-chloroanilino)- and4-(3'-bromoanilino)-6,7-dimethoxyquinazoline, possess the best combination of characteristics that warrant radioisotope labeling and further evaluation in tumor-bearing mice

  11. Receptor Tyrosine Kinase Expression Predicts Response to Sunitinib in Breast Cancer

    Science.gov (United States)

    Spanheimer, Philip M.; Lorenzen, Allison W.; De Andrade, James P.; Kulak, Mikhail V.; Carr, Jennifer C.; Woodfield, George W.; Sugg, Sonia L.; Weigel, Ronald J.

    2016-01-01

    Background Preliminary data indicate that tyrosine kinase inhibitors (TKIs) function through rearranged during transfection (RET) in breast cancer. However, TKIs are not specific and can block several receptor tyrosine kinases (RTKs). This study used cell lines and primary breast cancer specimens to determine factors associated with TKI response. Methods Proliferation was assessed after short interfering RNA knockdown with or without sunitinib in breast cancer cell lines by MTT (3-(4,5-dimethylhiazol-2-yl)-2,5-diphenyltetrazolium bromide). Breast cancer tissue and matched normal breast was obtained from 30 women with invasive breast carcinoma. Gene expression was assessed by reverse transcriptase-polymerase chain reaction. Fresh tissue was treated in vitro with sunitinib or control media for 30 min, and response was assessed by phosphorylation-specific western blot. Results The RTKs including epidermal growth factor receptor (EGFR), vascular endothelial growth factor receptor (VEGFR1-3), platelet-derived growth factor receptor (PDGFRa/b), and Kit were overexpressed in triple-negative breast tumors relative to HER2- and estrogen receptor-alpha (ERα)-positive tumors and normal breast tissue. Knockdown of EGFR reduced in vitro proliferation in MCF-7 and MDA-MB-231 but not in SKBR-3 or ZR-75-1 breast cancer cells. With the exception of RET, response to sunitinib was independent of RTK expression in all four cell lines. Both ERα-positive and low-EGFR-expressing tumors had an increased in vitro sunitinib response, as determined by alteration of Erk activation. Expression of other RTKs and additional clinical factors were not associated with response. Conclusion Triple-negative breast cancers overexpress RTKs but have decreased in vitro response to the TKI sunitinib. In addition to RET, TKIs that block EGFR may increase the therapeutic efficacy of TKIs in breast cancer. PMID:25971960

  12. Involvement of tyrosine residues located in the carboxyl tail of the human beta 2-adrenergic receptor in agonist-induced down-regulation of the receptor.

    OpenAIRE

    Valiquette, M; Bonin, H.; Hnatowich, M; Caron, M G; Lefkowitz, R J; Bouvier, M

    1990-01-01

    Chronic exposure of various cell types to adrenergic agonists leads to a decrease in cell surface beta 2-adrenergic receptor (beta 2AR) number. Sequestration of the receptor away from the cell surface as well as a down-regulation of the total number of cellular receptors are believed to contribute to this agonist-mediated regulation of receptor number. However, the molecular mechanisms underlying these phenomena are not well characterized. Recently, tyrosine residues located in the cytoplasmi...

  13. Tyrosine kinase signalling in breast cancer: Fibroblast growth factors and their receptors

    International Nuclear Information System (INIS)

    The fibroblast growth factors [Fgfs (murine), FGFs (human)] constitute a large family of ligands that signal through a class of cell-surface tyrosine kinase receptors. Fgf signalling has been associated in vitro with cellular differentiation as well as mitogenic and motogenic responses. In vivo, Fgfs are critical for animal development, and some have potent angiogenic properties. Several Fgfs have been identified as oncogenes in murine mammary cancer, where their deregulation is associated with proviral insertions of the mouse mammary tumour virus (MMTV). Thus, in some mammary tumours of MMTV-infected mouse strains, integration of viral genomic DNA into the somatic DNA of mammary epithelial cells was found to have caused the inappropriate expression of members of this family of growth factors. Although examination of human breast cancers has shown an altered expression of FGFs or of their receptors in some tumours, their role in the causation of breast disease is unclear and remains controversial

  14. The Cytoplasmic Adaptor Protein Dok7 Activates the Receptor Tyrosine Kinase MuSK via Dimerization

    Energy Technology Data Exchange (ETDEWEB)

    Bergamin, E.; Hallock, P; Burden, S; Hubbard, S

    2010-01-01

    Formation of the vertebrate neuromuscular junction requires, among others proteins, Agrin, a neuronally derived ligand, and the following muscle proteins: LRP4, the receptor for Agrin; MuSK, a receptor tyrosine kinase (RTK); and Dok7 (or Dok-7), a cytoplasmic adaptor protein. Dok7 comprises a pleckstrin-homology (PH) domain, a phosphotyrosine-binding (PTB) domain, and C-terminal sites of tyrosine phosphorylation. Unique among adaptor proteins recruited to RTKs, Dok7 is not only a substrate of MuSK, but also an activator of MuSK's kinase activity. Here, we present the crystal structure of the Dok7 PH-PTB domains in complex with a phosphopeptide representing the Dok7-binding site on MuSK. The structure and biochemical data reveal a dimeric arrangement of Dok7 PH-PTB that facilitates trans-autophosphorylation of the kinase activation loop. The structure provides the molecular basis for MuSK activation by Dok7 and for rationalizing several Dok7 loss-of-function mutations found in patients with congenital myasthenic syndromes.

  15. Radiation induction of the receptor tyrosine kinase gene Ptk-3 in normal rat astrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Sakuma, S.; Hideyuki, S.; Akihiro, I. [Univ. of Texas, Houston, TX (United States)] [and others

    1995-07-01

    Radiation-induced gene expression was examined in rat astrocyte cultures using differential display of mRNA via reverse transcriptase-polymerase chain reaction. A 0.3-kb cDNA that was consistently observed in irradiated cultures but not in unirradiated cultures was cloned and sequenced. It was found to be identical to Ptk-3, a receptor tyrosine kinase gene identified recently. The protein encoded by Ptk-3 is a member of a novel class of receptor tyrosine kinases whose extracellular domain contains regions of homology with coagulation factors V and VIII and complement component C1. Northern blot analysis revealed that the expression of Ptk-3 was increased in rat astrocytes by 0.5 h after exposure to 10 Gy and remained at the same elevated level for at least 24 h. The maximum increase occurred after 5 Gy cloning studies indicated the presence of at least two Ptk-3 mRNA transcripts, which are probable the result of an alternative splicing mechanism. The short isoform lacks a 37 amino acid sequence in the glycine/proline-rich juxtamembrane region. The splicing pattern of the Ptk-3 gene was not altered by radiation. However, the ratios of the longer to the shorter mRNA transcripts differed between adult cortex, neonatal cortex and in vitro astrocyte cultures. 36 refs., 5 figs.

  16. Radiation induction of the receptor tyrosine kinase gene Ptk-3 in normal rat astrocytes

    International Nuclear Information System (INIS)

    Radiation-induced gene expression was examined in rat astrocyte cultures using differential display of mRNA via reverse transcriptase-polymerase chain reaction. A 0.3-kb cDNA that was consistently observed in irradiated cultures but not in unirradiated cultures was cloned and sequenced. It was found to be identical to Ptk-3, a receptor tyrosine kinase gene identified recently. The protein encoded by Ptk-3 is a member of a novel class of receptor tyrosine kinases whose extracellular domain contains regions of homology with coagulation factors V and VIII and complement component C1. Northern blot analysis revealed that the expression of Ptk-3 was increased in rat astrocytes by 0.5 h after exposure to 10 Gy and remained at the same elevated level for at least 24 h. The maximum increase occurred after 5 Gy cloning studies indicated the presence of at least two Ptk-3 mRNA transcripts, which are probable the result of an alternative splicing mechanism. The short isoform lacks a 37 amino acid sequence in the glycine/proline-rich juxtamembrane region. The splicing pattern of the Ptk-3 gene was not altered by radiation. However, the ratios of the longer to the shorter mRNA transcripts differed between adult cortex, neonatal cortex and in vitro astrocyte cultures. 36 refs., 5 figs

  17. Role of Receptor Protein Tyrosine Phosphatase γ in Sensing Extracellular CO2 and HCO3.

    Science.gov (United States)

    Zhou, Yuehan; Skelton, Lara A; Xu, Lumei; Chandler, Margaret P; Berthiaume, Jessica M; Boron, Walter F

    2016-09-01

    Regulation of blood pH-critical for virtually every facet of life-requires that the renal proximal tubule (PT) adjust its rate of H(+) secretion (nearly the same as the rate of HCO3 (-) reabsorption, JHCO3 ) in response to changes in blood [CO2] and [HCO3 (-)]. Yet CO2/HCO3 (-) sensing mechanisms remain poorly characterized. Because receptor tyrosine kinase inhibitors render JHCO3 in the PT insensitive to changes in CO2 concentration, we hypothesized that the structural features of receptor protein tyrosine phosphatase-γ (RPTPγ) that are consistent with binding of extracellular CO2 or HCO3 (-) facilitate monitoring of blood CO2/HCO3 (-) concentrations. We now report that PTs express RPTPγ on blood-facing membranes. Moreover, RPTPγ deletion in mice eliminated the CO2 and HCO3 (-) sensitivities of JHCO3 as well as the normal defense of blood pH during whole-body acidosis. Thus, RPTPγ appears to be a novel extracellular CO2/HCO3 (-) sensor critical for pH homeostasis. PMID:26839367

  18. Expression and functional effects of Eph receptor tyrosine kinase A family members on Langerhans like dendritic cells

    Directory of Open Access Journals (Sweden)

    Finne Eivind

    2004-06-01

    Full Text Available Abstract Background The Eph receptors are the largest receptor tyrosine kinase family. Several family members are expressed in hematopoietic cells. Previously, the expression of a member of this family, EphA2, was identified on dendritic like cells in tonsils. We therefore specifically examined the expression of EphA2 on in vitro generated dendritic cells. Results In this study, expression of the EphA2 receptor was identified on in vitro generated Langerhans like dendritic cells compared to in vitro generated dendritic cells. We show that ligand induced engagement of the EphA2 receptor leads to receptor autophosphorylation indicating a functional receptor signaling pathway in these cells. We also observe phosphorylation and dephosphorylation of distinct proteins following ligand activation of EphA receptors. In co-stimulation assays, receptor-ligand interaction reduces the capacity of the Langerhans like dendritic cells to stimulate resting CD4+ T cells. Conclusion Engagement of EphA receptor tyrosine kinases on Langerhans like dendritic cells induces signaling as shown by tyrosine phosphorylation and dephosphorylation of distinct proteins. Furthermore this engagement renders the cells less capable of stimulating CD4+ T cells.

  19. Design of a selective insulin receptor tyrosine kinase inhibitor and its effect on glucose uptake and metabolism in intact cells

    International Nuclear Information System (INIS)

    An inhibitor of the insulin receptor tyrosine kinase (IRTK), (hydroxy-2-napthalenylmethyl)phosphonic acid, was designed and synthesized and was shown to be an inhibitor of the biological effects of insulin in vitro. With a wheat germ purified human placental insulin receptor preparation, this compound inhibited the insulin-stimulated autophosphorylation of the 95-kDa β-subunit of the insulin receptor. The ability of the kinase to phosphorylate an exogenous peptide substrate, angiotensin II, was also inhibited. Half-maximal inhibition of basal and insulin-stimulated human placental IRTK activity was found at concentrations of 150 and 100 μM, respectively, with 2 mM angiotensin II as the peptide substrate. The inhibitor was found to be specific for tyrosine kinases over serine kinases and noncompetitive with ATP. The inhibitor was converted into various (acyloxy)methyl prodrugs in order to achieve permeability through cell membranes. These prodrugs inhibited insulin-stimulated autophosphorylation of the insulin receptor 95-kDa β-subunit in intact CHO cells transfected with human insulin receptor. Inhibition of insulin-stimulated glucose oxidation in isolated rat adipocytes and 2-deoxyglucose uptake into CHO cells was observed with these prodrugs. The data provide additional evidence for the involvement of the insulin receptor tyrosine kinase in the regulation of glucose uptake and metabolism. These results and additional data reported herein suggest that this class of prodrugs and inhibitors will be useful for modulating the activity of a variety of tyrosine kinases

  20. Tyrosine kinase signalling in breast cancer: Epidermal growth factor receptor - convergence point for signal integration and diversification

    International Nuclear Information System (INIS)

    Cross-communication between different signalling systems is critical for the integration of multiple and changing environmental influences on individual cells. The epidermal growth factor receptor (EGFR) has been identified as a key element in the complex signalling network that is utilized by various classes of cell-surface receptors. This nonclassical mode of signalling system cross-talk, in distinction to receptor activation induced by cognate ligands, has been termed 'signal transactivation'. With the EGFR as the convergence point and distribution focus, this scenario may involve signals emitted by other members of the tyrosine kinase family, cytokine receptors, ion channels, G-protein-coupled receptors and integrins

  1. Tyrosine kinase signalling in breast cancer: Epidermal growth factor receptor and c-Src interactions in breast cancer

    International Nuclear Information System (INIS)

    Both the non-receptor tyrosine kinase, c-Src, and members of the epidermal growth factor (EGF) receptor family are overexpressed in high percentages of human breast cancers. Because these molecules are plasma membrane-associated and involved in mitogenesis, it has been speculated that they function in concert with one another to promote breast cancer development and progression. Evidence to date supports a model wherein c-Src potentiates the survival, proliferation and tumorigenesis of EGF receptor family members, in part by associating with them. Phosphorylation of the EGF receptor by c-SRC is also critical for mitogenic signaling initiated by the EGF receptor itself, as well as by several G-protein coupled receptors (GPCRs), a cytokine receptor, and the estrogen receptor. Thus, c-Src appears to have pleiotropic effects on cancer cells by modulating the action of multiple growth-promoting receptors

  2. Targeting the MET receptor tyrosine kinase in non-small cell lung cancer: emerging role of tivantinib

    International Nuclear Information System (INIS)

    MET receptor tyrosine kinase and its natural ligand, hepatocyte growth factor, have been implicated in a variety of cancers, including non-small cell lung cancer (NSCLC). Mechanisms by which cellular deregulation of MET occurs include overexpression, genomic amplification, mutation, or alternative splicing. MET overexpression or activation is a known cause of acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors in NSCLC. Inhibition of MET signaling in these EGFR tyrosine kinase inhibitor-resistant cells may potentially restore sensitivity to EGFR inhibitors. Tivantinib (ARQ 197), reported as a small-molecule MET inhibitor, has demonstrated antitumor activity in early clinical studies. This review focuses on MET and lung cancer, the clinical development of tivantinib, the clinical trials of tivantinib in NSCLC to date, its current/emerging role in the management of NSCLC, and future directions

  3. Human RON receptor tyrosine kinase induces complete epithelial-to-mesenchymal transition but causes cellular senescence

    International Nuclear Information System (INIS)

    The RON receptor tyrosine kinase is a member of the MET proto-oncogene family and is important for cell proliferation, differentiation, and cancer development. Here, we created a series of Madin-Darby canine kidney (MDCK) epithelial cell clones that express different levels of RON, and have investigated their biological properties. While low levels of RON correlated with little morphological change in MDCK cells, high levels of RON expression constitutively led to morphological scattering or complete and stabilized epithelial-to-mesenchymal transition (EMT). Unexpectedly, MDCK clones expressing higher levels of RON exhibited retarded proliferation and senescence, despite increased motility and invasiveness. RON was constitutively tyrosine-phosphorylated in MDCK cells expressing high levels of RON and undergoing EMT, and the MAPK signaling pathway was activated. This study reveals for the first time that RON alone is sufficient to induce complete and stabilized EMT in MDCK cells, and overexpression of RON does not cause cell transformation but rather induces cell cycle arrest and senescence, leading to impaired cell proliferation

  4. Functional analysis of the domains of the C elegans Ror receptor tyrosine kinase CAM-1.

    Science.gov (United States)

    Kim, Changsung; Forrester, Wayne C

    2003-12-15

    cam-1 encodes a Caenorhabditis elegans orphan receptor tyrosine kinase (RTK) of the Ror family that is required for cell migration and to orient cell polarity. Ror RTKs share a common domain structure. The predicted extracellular region contains immunoglobulin (Ig), cysteine-rich (CRD), and kringle (Kri) domains. Intracellularly are tyrosine kinase (Kin) and serine- and threonine (S/T)-rich domains. To investigate the functional requirement for CAM-1 domains in mediating cell migration, we engineered deletions that remove various domains and assessed the ability of these CAM-1 derivatives to rescue cam-1 mutant phenotypes. We find that the Ig, Kri, Kin, and S/T domains are dispensable for cell migration, but the CRD is required. Surprisingly, the entire intracellular region of CAM-1 is not required for proper cell migration. Most notably, a version of CAM-1 from which all domains besides the CRD and transmembrane domains have been deleted is able to rescue the migration of a single cell type, although not those of other cell types. Our results show that CAM-1 does not function exclusively as a canonical RTK and that it may function, at least in part, to regulate the distribution of a secreted ligand-possibly a Wnt protein. PMID:14651925

  5. Sequence of MET protooncogene cDNA has features characteristic of the tyrosine kinase family of growth-factor receptors

    International Nuclear Information System (INIS)

    The authors isolated overlapping cDNA clones corresponding to the major MET protooncogene transcript. The cDNA nucleotide sequence contained an open reading frame of 1408 amino acids with features characteristic of the tyrosine kinase family of growth factor receptors. These features include a putative 24-amino acid signal peptide and a candidate, hybrophobic, membrane-spanning segment of 23 amino acids, which defines an extracellular domain of 926 amino acids that could serve as a ligand-binding domain. A putative intracellular domain 435 amino acids long shows high homology with the SRC family of tyrosine kinases and within the kinase domain is most homologous with the human insulin receptor (44%) and v-abl (41%). Despite these similarities, however, they found no apparent sequence homology to other growth factor receptors in the putative ligand-binding domain. They conclude from the results that the MET protooncogene is a cell-surface receptor for an as-yet-unknown ligand

  6. The TAM family: phosphatidylserine sensing receptor tyrosine kinases gone awry in cancer.

    Science.gov (United States)

    Graham, Douglas K; DeRyckere, Deborah; Davies, Kurtis D; Earp, H Shelton

    2014-12-01

    The TYRO3, AXL (also known as UFO) and MERTK (TAM) family of receptor tyrosine kinases (RTKs) are aberrantly expressed in multiple haematological and epithelial malignancies. Rather than functioning as oncogenic drivers, their induction in tumour cells predominately promotes survival, chemoresistance and motility. The unique mode of maximal activation of this RTK family requires an extracellular lipid–protein complex. For example, the protein ligand, growth arrest-specific protein 6 (GAS6), binds to phosphatidylserine (PtdSer) that is externalized on apoptotic cell membranes, which activates MERTK on macrophages. This triggers engulfment of apoptotic material and subsequent anti-inflammatory macrophage polarization. In tumours, autocrine and paracrine ligands and apoptotic cells are abundant, which provide a survival signal to the tumour cell and favour an anti-inflammatory, immunosuppressive microenvironment. Thus, TAM kinase inhibition could stimulate antitumour immunity, reduce tumour cell survival, enhance chemosensitivity and diminish metastatic potential. PMID:25568918

  7. Whole Genome Duplications Shaped the Receptor Tyrosine Kinase Repertoire of Jawed Vertebrates.

    Science.gov (United States)

    Brunet, Frédéric G; Volff, Jean-Nicolas; Schartl, Manfred

    2016-01-01

    The receptor tyrosine kinase (RTK) gene family, involved primarily in cell growth and differentiation, comprises proteins with a common enzymatic tyrosine kinase intracellular domain adjacent to a transmembrane region. The amino-terminal portion of RTKs is extracellular and made of different domains, the combination of which characterizes each of the 20 RTK subfamilies among mammals. We analyzed a total of 7,376 RTK sequences among 143 vertebrate species to provide here the first comprehensive census of the jawed vertebrate repertoire. We ascertained the 58 genes previously described in the human and mouse genomes and established their phylogenetic relationships. We also identified five additional RTKs amounting to a total of 63 genes in jawed vertebrates. We found that the vertebrate RTK gene family has been shaped by the two successive rounds of whole genome duplications (WGD) called 1R and 2R (1R/2R) that occurred at the base of the vertebrates. In addition, the Vegfr and Ephrin receptor subfamilies were expanded by single gene duplications. In teleost fish, 23 additional RTK genes have been retained after another expansion through the fish-specific third round (3R) of WGD. Several lineage-specific gene losses were observed. For instance, birds have lost three RTKs, and different genes are missing in several fish sublineages. The RTK gene family presents an unusual high gene retention rate from the vertebrate WGDs (58.75% after 1R/2R, 64.4% after 3R), resulting in an expansion that might be correlated with the evolution of complexity of vertebrate cellular communication and intracellular signaling. PMID:27260203

  8. Epidermal growth factor receptor activation by diesel particles is mediated by tyrosine phosphatase inhibition

    International Nuclear Information System (INIS)

    Exposure to particulate matter (PM) is associated with increased cardiopulmonary morbidity and mortality. Diesel exhaust particles (DEP) are a major component of ambient PM and may contribute to PM-induced pulmonary inflammation. Proinflammatory signaling is mediated by phosphorylation-dependent signaling pathways whose activation is opposed by the activity of protein tyrosine phosphatases (PTPases) which thereby function to maintain signaling quiescence. PTPases contain an invariant catalytic cysteine that is susceptible to electrophilic attack. DEP contain electrophilic oxy-organic compounds that may contribute to the oxidant effects of PM. Therefore, we hypothesized that exposure to DEP impairs PTPase activity allowing for unopposed basal kinase activity. Here we report that exposure to 30 μg/cm2 DEP for 4 h induces differential activation of signaling in primary cultures of human airway epithelial cells (HAEC), a primary target cell in PM inhalation. In-gel kinase activity assay of HAEC exposed to DEPs of low (L-DEP), intermediate (I-DEP) or high (H-DEP) organic content showed differential activation of intracellular kinases. Exposure to these DEP also induced varying levels of phosphorylation of the receptor tyrosine kinase EGFR in a manner that requires EGFR kinase activity but does not involve receptor dimerization. We demonstrate that treatment with DEP results in an impairment of total and EGFR-directed PTPase activity in HAEC with a potency that is independent of the organic content of these particles. These data show that DEP-induced EGFR phosphorylation in HAEC is the result of a loss of PTPase activities which normally function to dephosphorylate EGFR in opposition to baseline EGFR kinase activity

  9. Functional activation of the T-cell antigen receptor induces tyrosine phosphorylation of phospholipase C-gamma 1.

    OpenAIRE

    Weiss, A; Koretzky, G; Schatzman, R C; Kadlecek, T

    1991-01-01

    Stimulation of the T-cell antigen receptor (TCR), which itself is not a protein-tyrosine kinase (PTK), activates a PTK and phospholipase C (PLC). Using the human T-cell leukemic line Jurkat and normal peripheral blood lymphocytes, we demonstrate that stimulation of the TCR specifically induces the recovery of PLC activity in eluates from anti-phosphotyrosine immunoprecipitates. Stimulation of the human muscarinic receptor, subtype 1, when expressed in Jurkat activates PLC through a guanine nu...

  10. Identification of tyrosine residues within the intracellular domain of the erythropoietin receptor crucial for STAT5 activation.

    OpenAIRE

    Gobert, S.; Chretien, S; Gouilleux, F; Muller, O.; Pallard, C; Dusanter-Fourt, I; Groner, B; Lacombe, C.; Gisselbrecht, S; Mayeux, P

    1996-01-01

    FDCP-1 cells are hematopoietic progenitor cells which require interleukin-3 for survival and proliferation. FDCP-1 cells stably transfected with the murine erythropoietin receptor cDNA survive and proliferate in the presence of erythropoietin. Erythropoietin induces the activation of the short forms (80 kDa) of STAT5 in the cells. Erythropoietin-induced activation of STAT5 was strongly reduced in cells expressing mutated variants of the erythropoietin receptors in which tyrosine residues in t...

  11. Neuromedin B receptors regulate EGF receptor tyrosine phosphorylation in lung cancer cells

    OpenAIRE

    Moody, Terry W.; Berna, Marc J.; Mantey, Samuel; Sancho, Veronica; Ridnour, Lisa; Wink, David A.; Chan, Daniel; Giaccone, Giuseppe; Jensen, Robert T.

    2010-01-01

    Neuromedin B (NMB), a member of the bombesin family of peptides, is an autocrine growth factor for many lung cancer cells. The present study investigated the ability of NMB to cause transactivation of the epidermal growth factor (EGF) receptor in lung cancer cells. By Western blot, addition of NMB or related peptides to NCI-H1299 human non-small cell lung cancer (NSCLC) cells, caused phosphorylation of Tyr1068 of the EGF receptor. The signal was amplified using NCI-H1299 cells stably transect...

  12. Role of ErbB family receptor tyrosine kinases in intrahepatic cholangiocarcinoma

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Aberrant expression and signaling of epidermal growth factor receptor (ErbB) family receptor tyrosine kinases, most notably that of ErbB2 and ErbB1, have been implicated in the molecular pathogenesis of intrahepatic cholangiocarcinoma. Constitutive overexpression of ErbB2 and/or ErbB1 in malignant cholangiocytes has raised interest in the possibility that agents which selectively target these receptors could potentially be effective in cholangiocarcinoma therapy. However, current experience with such ErbB-directed therapies have at best produced only modest responses in patients with biliary tract cancers. This review provides a comprehensive and critical analysis of both preclinical and clinical studies aimed at assessing the role of altered ErbB2 and/or ErbB1 expression, genetic modifications, and dysregulated signaling on cholangiocarcinoma development and progression. Specific limitations in experimental approaches that have been used to assess human cholangiocarcinoma specimens for ErbB2 and/or ErbB1 overexpression and gene amplification are discussed. In addition, current rodent models of intrahepatic cholangiocarcinogenesis associated with constitutive ErbB2 overexpression are reviewed. Select interactive relationships between ErbB2 or ErbB1 with other relevant molecular signaling pathways associated with intrahepatic cholangiocarcinoma development and progression are also detailed, including those linking ErbB receptors to bile acid, cyclooxygenase-2, interleukin-6/gp130, transmembrane mucins, hepatocyte growth factor/Met, and vascular endothelial growth factor signaling. Lastly, various factors that can limit therapeutic efficacy of ErbB-targeted agents against cholangiocarcinoma are considered.

  13. Role of ErbB family receptor tyrosine kinases in intrahepatic cholangiocarcinoma.

    Science.gov (United States)

    Sirica, Alphonse-E

    2008-12-14

    Aberrant expression and signaling of epidermal growth factor receptor (ErbB) family receptor tyrosine kinases, most notably that of ErbB2 and ErbB1, have been implicated in the molecular pathogenesis of intrahepatic cholangiocarcinoma. Constitutive overexpression of ErbB2 and/or ErbB1 in malignant cholangiocytes has raised interest in the possibility that agents which selectively target these receptors could potentially be effective in cholangiocarcinoma therapy. However, current experience with such ErbB-directed therapies have at best produced only modest responses in patients with biliary tract cancers. This review provides a comprehensive and critical analysis of both preclinical and clinical studies aimed at assessing the role of altered ErbB2 and/or ErbB1 expression, genetic modifications, and dysregulated signaling on cholangiocarcinoma development and progression. Specific limitations in experimental approaches that have been used to assess human cholangiocarcinoma specimens for ErbB2 and/or ErbB1 overexpression and gene amplification are discussed. In addition, current rodent models of intrahepatic cholangiocarcinogenesis associated with constitutive ErbB2 overexpression are reviewed. Select interactive relationships between ErbB2 or ErbB1 with other relevant molecular signaling pathways associated with intrahepatic cholangiocarcinoma development and progression are also detailed, including those linking ErbB receptors to bile acid, cyclooxygenase-2, interleukin-6/gp130, transmembrane mucins, hepatocyte growth factor/Met, and vascular endothelial growth factor signaling. Lastly, various factors that can limit therapeutic efficacy of ErbB-targeted agents against cholangiocarcinoma are considered. PMID:19084911

  14. Mice lacking Axl and Mer tyrosine kinase receptors are susceptible to experimental autoimmune orchitis induction.

    Science.gov (United States)

    Li, Nan; Liu, Zhenghui; Zhang, Yue; Chen, Qiaoyuan; Liu, Peng; Cheng, C Yan; Lee, Will M; Chen, Yongmei; Han, Daishu

    2015-03-01

    The mammalian testis is an immunoprivileged organ where male germ cell autoantigens are immunologically ignored. Both systemic immune tolerance to autoantigens and local immunosuppressive milieu contribute to the testicular immune privilege. Testicular immunosuppression has been intensively studied, but information on systemic immune tolerance to autoantigens is lacking. In the present study, we aimed to determine the role of Axl and Mer receptor tyrosine kinases in maintaining the systemic tolerance to male germ cell antigens using the experimental autoimmune orchitis (EAO) model. Axl and Mer double-knockout (Axl(-/-)Mer(-/-)) mice developed evident EAO after a single immunization with germ cell homogenates emulsified with complete Freund's adjuvant. EAO was characterized by the accumulation of macrophages and T lymphocytes in the testis. Damage to the seminiferous epithelium was also observed. EAO induction was associated with pro-inflammatory cytokine upregulation in the testes, impaired permeability of the blood-testis barrier and generation of autoantibodies against germ cell antigens in Axl(-/-)Mer(-/-) mice. Immunization also induced mild EAO in Axl or Mer single-gene-knockout mice. By contrast, a single immunization failed to induce EAO in wild-type mice. The results indicate that Axl and Mer receptors cooperatively regulate the systemic immune tolerance to male germ cell antigens. PMID:25403570

  15. Aberrant Mer receptor tyrosine kinase expression contributes to leukemogenesis in acute myeloid leukemia.

    Science.gov (United States)

    Lee-Sherick, A B; Eisenman, K M; Sather, S; McGranahan, A; Armistead, P M; McGary, C S; Hunsucker, S A; Schlegel, J; Martinson, H; Cannon, C; Keating, A K; Earp, H S; Liang, X; DeRyckere, D; Graham, D K

    2013-11-14

    Acute myeloid leukemia (AML) continues to be extremely difficult to treat successfully, and the unacceptably low overall survival rates mandate that we assess new potential therapies to ameliorate poor clinical response to conventional therapy. Abnormal tyrosine kinase activation in AML has been associated with poor prognosis and provides strategic targets for novel therapy development. We found that Mer receptor tyrosine kinase was over-expressed in a majority of pediatric (29/36, 80%) and adult (10/10, 100%) primary AML patient blasts at the time of diagnosis, and 100% of patient samples at the time of relapse. Mer was also found to be expressed in 12 of 14 AML cell lines (86%). In contrast, normal bone marrow myeloid precursors expressed little to no Mer. Following AML cell line stimulation with Gas6, a Mer ligand, we observed activation of prosurvival and proliferative signaling pathways, including phosphorylation of ERK1/2, p38, MSK1, CREB, ATF1, AKT and STAT6. To assess the phenotypic role of Mer in AML, two independent short-hairpin RNA (shRNA) constructs were used to decrease Mer expression in the AML cell lines Nomo-1 and Kasumi-1. Reduction of Mer protein levels significantly increased rates of myeloblast apoptosis two to threefold in response to serum starvation. Furthermore, myeloblasts with knocked-down Mer demonstrated decreased colony formation by 67-87%, relative to control cell lines (P<0.01). NOD-SCID-gamma mice transplanted with Nomo-1 myeloblasts with reduced levels of Mer had a significant prolongation in survival compared with mice transplanted with the parental or control cell lines (median survival 17 days in parental and control cell lines, versus 32-36 days in Mer knockdown cell lines, P<0.0001). These data suggest a role for Mer in acute myeloid leukemogenesis and indicate that targeted inhibition of Mer may be an effective therapeutic strategy in pediatric and adult AML. PMID:23474756

  16. The c-Met receptor tyrosine kinase inhibitor MP470 radiosensitizes glioblastoma cells

    International Nuclear Information System (INIS)

    Glioblastoma multiforme (GBM) is resistant to current cytotoxic therapies, in part because of enhanced DNA repair. Activation of the receptor tyrosine kinase c-Met has been shown to protect cancer cells from DNA damage. We hypothesized that inhibiting c-Met would decrease this protection and thus sensitize resistant tumor cells to the effects of radiation therapy. Eight human GBM cell lines were screened for radiosensitivity to the small-molecule c-Met inhibitor MP470 with colony-count assays. Double-strand (ds) DNA breaks was quantified by using antibodies to gamma H2AX. Western blotting demonstrate expression of RAD51, glycogen synthase kinase (GSK)-3β, and other proteins. A murine xenograft tumor flank model was used for in vivo radiosensitization studies. MP470 reduced c-Met phosphorylation and enhanced radiation-induced cell kill by 0.4 logs in SF767 cells. Cells pretreated with MP470 had more ds DNA damage than cells treated with radiation alone. Mechanistically, MP470 was shown to inhibit dsDNA break repair and increase apoptosis. MP470 influences various survival and DNA repair related proteins such as pAKT, RAD51 and GSK3β. In vivo, the addition of MP470 to radiation resulted in a tumor-growth-delay enhancement ratio of 2.9 over radiation alone and extended survival time. GBM is a disease site where radiation is often used to address both macroscopic and microscopic disease. Despite attempts at dose escalation outcomes remain poor. MP470, a potent small-molecule tyrosine kinase inhibitor of c-Met, radiosensitized several GBM cell lines both in vitro and in vivo, and may help to improve outcomes for patients with GBM

  17. Targeting the EGF receptor in ovarian cancer with the tyrosine kinase inhibitor ZD 1839 (‘Iressa’)

    OpenAIRE

    Sewell, J M; Macleod, K G; A. Ritchie; Smyth, J F; Langdon, S. P.

    2002-01-01

    The modulating effects of the orally active epidermal growth factor receptor-specific tyrosine kinase inhibitor ZD 1839 (‘Iressa’) on cell growth and signalling were evaluated in four ovarian cancer cell lines (PE01, PE04, SKOV-3, OVCAR-5) that express the epidermal growth factor receptor, and in A2780, which is epidermal growth factor receptor-negative. Transforming growth factor-α stimulated growth was completely inhibited by concentrations of ZD 1839 ⩾0.3 μM in the epidermal growth factor ...

  18. Multiple angiopoietin recombinant proteins activate the Tie1 receptor tyrosine kinase and promote its interaction with Tie2

    OpenAIRE

    Saharinen, Pipsa; Kerkelä, Katja; Ekman, Niklas; Marron, Marie; Brindle, Nicholas; Lee, Gyun Min; Augustin, Hellmut; Koh, Gou Young; Alitalo, Kari

    2005-01-01

    The Tie1 receptor tyrosine kinase was isolated over a decade ago, but so far no ligand has been found to activate this receptor. Here, we have examined the potential of angiopoietins, ligands for the related Tie2 receptor, to mediate Tie1 activation. We show that a soluble Ang1 chimeric protein, COMP-Ang1, stimulates Tie1 phosphorylation in endothelial cells with similar kinetics and angiopoietin dose dependence when compared with Tie2. The phosphorylation of overexpressed Tie1 was weakly ind...

  19. Novel Mechanism for Suppression of Hyperpolarization-activated Cyclic Nucleotide-gated Pacemaker Channels by Receptor-like Tyrosine Phosphatase-α*

    OpenAIRE

    Huang, Jianying; Huang, Aijie; Zhang, Qi; Lin, Yen-Chang; Yu, Han-Gang

    2008-01-01

    We have previously reported an important role of increased tyrosine phosphorylation activity by Src in the modulation of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. Here we provide evidence showing a novel mechanism of decreased tyrosine phosphorylation on HCN channel properties. We found that the receptor-like protein-tyrosine phosphatase-α (RPTPα) significantly inhibited or eliminated HCN2 channel expression in HEK293 cells. Biochemical eviden...

  20. Growth Hormone-induced JAK2 Signaling and GH Receptor Down-regulation: Role of GH Receptor Intracellular Domain Tyrosine Residues

    OpenAIRE

    Deng, Luqin; Jiang, Jing; Frank, Stuart J.

    2012-01-01

    GH receptor (GHR) mediates important somatogenic and metabolic effects of GH. A thorough understanding of GH action requires intimate knowledge of GHR activation mechanisms, as well as determinants of GH-induced receptor down-regulation. We previously demonstrated that a GHR mutant in which all intracellular tyrosine residues were changed to phenylalanine was defective in its ability to activate signal transducer and activator of transcription (STAT)5 and deficient in GH-induced down-regulati...

  1. The Plasticity of Oncogene Addiction: Implications for Targeted Therapies Directed to Receptor Tyrosine Kinases

    Directory of Open Access Journals (Sweden)

    Vinochani Pillay

    2009-05-01

    Full Text Available A common mutation of the epidermal growth factor receptor (EGFR in glioblastoma multiforme (GBM is an extracellular truncation known as the de2-7 EGFR (or EGFRvIII. Hepatocyte growth factor (HGF is the ligand for the receptor tyrosine kinase (RTK c-Met, and this signaling axis is often active in GBM. The expression of the HGF/c-Met axis or de2-7 EGFR independently enhances GBMgrowth and invasiveness, particularly through the phosphatidylinositol-3 kinase/pAkt pathway. Using RTK arrays, we show that expression of de2-7 EGFR in U87MG GBM cells leads to the coactivation of several RTKs, including platelet-derived growth factor receptor β and c-Met. A neutralizing antibody to HGF (AMG102 did not inhibit de2-7 EGFR-mediated activation of c-Met, demonstrating that it is ligand-independent. Therapy for parental U87MG xenografts with AMG 102 resulted in significant inhibition of tumor growth, whereas U87MG.Δ2-7 xenografts were profoundly resistant. Treatment of U87MG.Δ2-7 xenografts with panitumumab, an anti-EGFR antibody, only partially inhibited tumor growth as xenografts rapidly reverted to the HGF/c-Met signaling pathway. Cotreatment with panitumumab and AMG 102 prevented this escape leading to significant tumor inhibition through an apoptotic mechanism, consistent with the induction of oncogenic shock. This observation provides a rationale for using panitumumab and AMG 102 in combination for the treatment of GBM patients. These results illustrate that GBM cells can rapidly change the RTK driving their oncogene addiction if the alternate RTK signals through the same downstream pathway. Consequently, inhibition of a dominant oncogene by targeted therapy can alter the hierarchy of RTKs resulting in rapid therapeutic resistance.

  2. Identification of the insulin receptor tyrosine residues undergoing insulin-stimulated phosphorylation in intact rat hepatoma cells

    International Nuclear Information System (INIS)

    Tyr(P)-containing proteins were purified from extracts of insulin-treated rat hepatoma cells (H4-II-E-C3) by antiphosphotyrosine immunoaffinity chromatography. Two major insulin-stimulated, Tyr(P) proteins were recovered: an M/sub r/ 95,000 protein (identified as the insulin receptor β subunit by its immunoprecipitation by a patient-derived anti-insulin receptor serum and several anti-insulin receptor (peptide) anti-sera) and an M/sub r/ 180,000 protein. After purification and tryptic digestion of the M/sub r/ 95,000 protein, tryptic peptides containing Tyr (P) were purified by sequential antiphosphotyrosine immunoaffinity, reversed-phase, anion-exchange chromatography. Approximately 80% of all β subunit [32P]Tyr(P) resides on two tryptic peptides: 50-60% of [32P]Tyr(P) is found on the tryptic peptide Asp-Ile-Try-Glu-Thr-Asp-Try-Try-Arg from the tyrosine kinase domain. A second tryptic peptide is located near the carboxyl terminus; this contains 20-30% of β subunit [32P]Tyr(P) and is identified primarily in a double phosphorylated form. In a summary, the insulin-stimulated tyrosine phosphorylation of the insulin receptor in intact rat hepatoma cells involves at least 6 of the 13 tyrosine residues located on the β subunit intracellular extension. These tyrosines are clustered in several domains in a distribution virtually identical to that previously found for partially purified human insulin receptor autophosphorylated in vitro in the presence of insulin

  3. Receptor tyrosine kinase (c-Kit) inhibitors: a potential therapeutic target in cancer cells

    Science.gov (United States)

    Abbaspour Babaei, Maryam; Kamalidehghan, Behnam; Saleem, Mohammad; Huri, Hasniza Zaman; Ahmadipour, Fatemeh

    2016-01-01

    c-Kit, a receptor tyrosine kinase, is involved in intracellular signaling, and the mutated form of c-Kit plays a crucial role in occurrence of some cancers. The function of c-Kit has led to the concept that inhibiting c-Kit kinase activity can be a target for cancer therapy. The promising results of inhibition of c-Kit for treatment of cancers have been observed in some cancers such as gastrointestinal stromal tumor, acute myeloid leukemia, melanoma, and other tumors, and these results have encouraged attempts toward improvement of using c-Kit as a capable target for cancer therapy. This paper presents the findings of previous studies regarding c-Kit as a receptor tyrosine kinase and an oncogene, as well as its gene targets and signaling pathways in normal and cancer cells. The c-Kit gene location, protein structure, and the role of c-Kit in normal cell have been discussed. Comprehending the molecular mechanism underlying c-Kit-mediated tumorogenesis is consequently essential and may lead to the identification of future novel drug targets. The potential mechanisms by which c-Kit induces cellular transformation have been described. This study aims to elucidate the function of c-Kit for future cancer therapy. In addition, it has c-Kit inhibitor drug properties and their functions have been listed in tables and demonstrated in schematic pictures. This review also has collected previous studies that targeted c-Kit as a novel strategy for cancer therapy. This paper further emphasizes the advantages of this approach, as well as the limitations that must be addressed in the future. Finally, although c-Kit is an attractive target for cancer therapy, based on the outcomes of treatment of patients with c-Kit inhibitors, it is unlikely that Kit inhibitors alone can lead to cure. It seems that c-Kit mutations alone are not sufficient for tumorogenesis, but do play a crucial role in cancer occurrence. PMID:27536065

  4. Receptor-type Protein Tyrosine Phosphatase β Regulates Met Phosphorylation and Function in Head and Neck Squamous Cell Carcinoma

    Directory of Open Access Journals (Sweden)

    Yiru Xu

    2012-11-01

    Full Text Available Head and neck squamous cell carcinoma (HNSCC is the sixth most common cancer and has a high rate of mortality. Emerging evidence indicates that hepatocyte growth factor receptor (or Met pathway plays a pivotal role in HNSCC metastasis and resistance to chemotherapy. Met function is dependent on tyrosine phosphorylation that is under direct control by receptor-type protein tyrosine phosphatase β (RPTP-β. We report here that RPTP-β expression is significantly downregulated in HNSCC cells derived from metastatic tumors compared to subject-matched cells from primary tumors. Knockdown of endogenous RPTP-β in HNSCC cells from primary tumor potentiated Met tyrosine phosphorylation, downstream mitogen-activated protein (MAP kinase pathway activation, cell migration, and invasion. Conversely, restoration of RPTP-β expression in cells from matched metastatic tumor decreased Met tyrosine phosphorylation and downstream functions. Furthermore, we observed that six of eight HNSCC tumors had reduced levels of RPTP-β protein in comparison with normal oral tissues. Collectively, the results demonstrate the importance of RPTP-β in tumor biology of HNSCC through direct dephosphorylation of Met and regulation of downstream signal transduction pathways. Reduced RPTP-β levels, with or without Met overexpression, could promote Met activation in HNSCC tumors.

  5. Investigation of the expression of the EphB4 receptor tyrosine kinase in prostate carcinoma

    Directory of Open Access Journals (Sweden)

    Douglas Evelyn L

    2005-09-01

    Full Text Available Abstract Background The EphB4 receptor tyrosine kinase has been reported as increased in tumours originating from several different tissues and its expression in a prostate cancer xenograft model has been reported. Methods RT-PCR, western blotting and immunohistochemical techniques were used to examine EphB4 expression and protein levels in human prostate cancer cell lines LNCaP, DU145 and PC3. Immunohistochemistry was also used to examine localisation of EphB4 in tissue samples from 15 patients with prostate carcinomas. Results All three prostate cancer cell lines expressed the EphB4 gene and protein. EphB4 immunoreactivity in vivo was significantly greater in human prostate cancers as compared with matched normal prostate epithelium and there appeared to be a trend towards increased expression with higher grade disease. Conclusion EphB4 is expressed in prostate cancer cell lines with increased expression in human prostate cancers when compared with matched normal tissue. EphB4 may therefore be a useful anti-prostate cancer target.

  6. Dialkoxyquinazolines: Screening Epidermal Growth Factor ReceptorTyrosine Kinase Inhibitors for Potential Tumor Imaging Probes

    Energy Technology Data Exchange (ETDEWEB)

    VanBrocklin, Henry F.; Lim, John K.; Coffing, Stephanie L.; Hom,Darren L.; Negash, Kitaw; Ono, Michele Y.; Hanrahan, Stephen M.; Taylor,Scott E.; Vanderpoel, Jennifer L.; Slavik, Sarah M.; Morris, Andrew B.; Riese II, David J.

    2005-09-01

    The epidermal growth factor receptor (EGFR), a long-standingdrug development target, is also a desirable target for imaging. Sixteendialkoxyquinazoline analogs, suitable for labeling with positron-emittingisotopes, have been synthesized and evaluated in a battery of in vitroassays to ascertain their chemical and biological properties. Thesecharacteristics provided the basis for the adoption of a selection schemato identify lead molecules for labeling and in vivo evaluation. A newEGFR tyrosine kinase radiometric binding assay revealed that all of thecompounds possessed suitable affinity (IC50 = 0.4 - 51 nM) for the EGFRtyrosine kinase. All of the analogs inhibited ligand-induced EGFRtyrosine phosphorylation (IC50 = 0.8 - 20 nM). The HPLC-estimatedoctanol/water partition coefficients ranged from 2.0-5.5. Four compounds,4-(2'-fluoroanilino)- and 4-(3'-fluoroanilino)-6,7-diethoxyquinazoline aswell as 4-(3'-chloroanilino)- and4-(3'-bromoanilino)-6,7-dimethoxyquinazoline, possess the bestcombination of characteristics that warrant radioisotope labeling andfurther evaluation in tumor-bearing mice.

  7. Mer receptor tyrosine kinase is a therapeutic target in pre–B-cell acute lymphoblastic leukemia

    Science.gov (United States)

    Linger, Rachel M. A.; Lee-Sherick, Alisa B.; DeRyckere, Deborah; Cohen, Rebecca A.; Jacobsen, Kristen M.; McGranahan, Amy; Brandão, Luis N.; Winges, Amanda; Sawczyn, Kelly K.; Liang, Xiayuan; Keating, Amy K.; Tan, Aik Choon; Earp, H. Shelton

    2013-01-01

    Acute lymphoblastic leukemia (ALL) is currently treated with an intense regimen of chemotherapy yielding cure rates near 85%. However, alterations to treatment strategies using available drugs are unlikely to provide significant improvement in survival or decrease therapy-associated toxicities. Here, we report ectopic expression of the Mer receptor tyrosine kinase in pre–B-cell ALL (B-ALL) cell lines and pediatric patient samples. Inhibition of Mer in B-ALL cell lines decreased activation of AKT and MAPKs and led to transcriptional changes, including decreased expression of antiapoptotic PRKCB gene and increase in proapoptotic BAX and BBC3 genes. Further, Mer inhibition promoted chemosensitization, decreased colony-forming potential in clonogenic assays, and delayed disease onset in a mouse xenograft model of leukemia. Our results identify Mer as a potential therapeutic target in B-ALL and suggest that inhibitors of Mer may potentiate lymphoblast killing when used in combination with chemotherapy. This strategy could reduce minimal residual disease and/or allow for chemotherapy dose reduction, thereby leading to improved event-free survival and reduced therapy-associated toxicity for patients with B-ALL. Additionally, Mer is aberrantly expressed in numerous other malignancies suggesting that this approach may have broad applications. PMID:23861246

  8. Mer receptor tyrosine kinase is a therapeutic target in pre-B-cell acute lymphoblastic leukemia.

    Science.gov (United States)

    Linger, Rachel M A; Lee-Sherick, Alisa B; DeRyckere, Deborah; Cohen, Rebecca A; Jacobsen, Kristen M; McGranahan, Amy; Brandão, Luis N; Winges, Amanda; Sawczyn, Kelly K; Liang, Xiayuan; Keating, Amy K; Tan, Aik Choon; Earp, H Shelton; Graham, Douglas K

    2013-08-29

    Acute lymphoblastic leukemia (ALL) is currently treated with an intense regimen of chemotherapy yielding cure rates near 85%. However, alterations to treatment strategies using available drugs are unlikely to provide significant improvement in survival or decrease therapy-associated toxicities. Here, we report ectopic expression of the Mer receptor tyrosine kinase in pre-B-cell ALL (B-ALL) cell lines and pediatric patient samples. Inhibition of Mer in B-ALL cell lines decreased activation of AKT and MAPKs and led to transcriptional changes, including decreased expression of antiapoptotic PRKCB gene and increase in proapoptotic BAX and BBC3 genes. Further, Mer inhibition promoted chemosensitization, decreased colony-forming potential in clonogenic assays, and delayed disease onset in a mouse xenograft model of leukemia. Our results identify Mer as a potential therapeutic target in B-ALL and suggest that inhibitors of Mer may potentiate lymphoblast killing when used in combination with chemotherapy. This strategy could reduce minimal residual disease and/or allow for chemotherapy dose reduction, thereby leading to improved event-free survival and reduced therapy-associated toxicity for patients with B-ALL. Additionally, Mer is aberrantly expressed in numerous other malignancies suggesting that this approach may have broad applications. PMID:23861246

  9. Axl, a receptor tyrosine kinase, mediates flow-induced vascular remodeling.

    Science.gov (United States)

    Korshunov, Vyacheslav A; Mohan, Amy M; Georger, Mary A; Berk, Bradford C

    2006-06-01

    Intima-media thickening (IMT) in response to hemodynamic stress is a physiological process that requires coordinated signaling among endothelial, inflammatory, and vascular smooth muscle cells (VSMC). Axl, a receptor tyrosine kinase, whose ligand is Gas6, is highly induced in VSMC after carotid injury. Because Axl regulates cell migration, phagocytosis and apoptosis, we hypothesized that Axl would play a role in IMT. Vascular remodeling in mice deficient in Axl (Axl(-/-)) and wild-type littermates (Axl(+/+)) was induced by ligation of the left carotid artery (LCA) branches maintaining flow via the left occipital artery. Both genotypes had similar baseline hemodynamic parameters and carotid artery structure. Partial ligation altered blood flow equally in both genotypes: increased by 60% in the right carotid artery (RCA) and decreased by 80% in the LCA. There were no significant differences in RCA remodeling between genotypes. However, in the LCA Axl(-/-) developed significantly smaller intima+media compared with Axl(+/+) (31+/-4 versus 42+/-6x10(-6) microm3, respectively). Quantitative immunohistochemistry of Axl(-/-) LCA showed increased apoptosis compared with Axl(+/+) (5-fold). As expected, p-Akt was decreased in Axl(-/-), whereas there was no difference in Gas6 expression. Cell composition also changed significantly, with increases in CD45+ cells and decreases in VSMC, macrophages, and neutrophils in Axl(-/-) compared with Axl(+/+). These data demonstrate an important role for Axl in flow-dependent remodeling by regulating vascular apoptosis and vascular inflammation. PMID:16627783

  10. Protein tyrosine phosphatase non-receptor type 2 and inflammatory bowel disease.

    Science.gov (United States)

    Spalinger, Marianne R; McCole, Declan F; Rogler, Gerhard; Scharl, Michael

    2016-01-21

    Genome wide association studies have associated single nucleotide polymorphisms within the gene locus encoding protein tyrosine phosphatase non-receptor type 2 (PTPN2) with the onset of inflammatory bowel disease (IBD) and other inflammatory disorders. Expression of PTPN2 is enhanced in actively inflamed intestinal tissue featuring a marked up-regulation in intestinal epithelial cells. PTPN2 deficient mice suffer from severe intestinal and systemic inflammation and display aberrant innate and adaptive immune responses. In particular, PTPN2 is involved in the regulation of inflammatory signalling cascades, and critical for protecting intestinal epithelial barrier function, regulating innate and adaptive immune responses, and finally for maintaining intestinal homeostasis. On one hand, dysfunction of PTPN2 has drastic effects on innate host defence mechanisms, including increased secretion of pro-inflammatory cytokines, limited autophagosome formation in response to invading pathogens, and disruption of the intestinal epithelial barrier. On the other hand, PTPN2 function is crucial for controlling adaptive immune functions, by regulating T cell proliferation and differentiation as well as maintaining T cell tolerance. In this way, dysfunction of PTPN2 contributes to the manifestation of IBD. The aim of this review is to present an overview of recent findings on the role of PTPN2 in intestinal homeostasis and the impact of dysfunctional PTPN2 on intestinal inflammation. PMID:26811645

  11. Epidermal growth factor stimulates tyrosine phosphorylation of phospholipase C-II independently of receptor internalization and extracellular calcium.

    OpenAIRE

    Wahl, M I; Nishibe, S; Suh, P G; Rhee, S G; Carpenter, G.

    1989-01-01

    Epidermal growth factor (EGF) rapidly stimulates the formation of inositol 1,4,5-trisphosphate in a variety of cell types. Previously we have found that in intact cells stimulation of phospholipase C (PLC) activity by EGF is correlated with the retention of increased amounts of PLC activity by a phosphotyrosine immunoaffinity matrix, suggesting that the EGF-receptor tyrosine kinase phosphorylates PLC. We now define parameters of the mechanism by which EGF addition to A-431 cells stimulates ph...

  12. Mer receptor tyrosine kinase is frequently overexpressed in human non-small cell lung cancer, confirming resistance to erlotinib

    OpenAIRE

    Xie, Shengzhi; Li, Yongwu; Li, Xiaoyan; WANG, LINXIONG; Yang, Na; Wang, Yadi; Wei, Huafeng

    2015-01-01

    Mer is a receptor tyrosine kinase (RTK) with oncogenic properties that is often overexpressed or activated in various malignancies. Using both immunohistochemistry and microarray analyses, we demonstrated that Mer was overexpressed in both tumoral and stromal compartments of about 70% of non-small cell lung cancer (NSCLC) samples relative to surrounding normal lung tissue. This was validated in freshly harvested NSCLC samples; however, no associations were found between Mer expression and pat...

  13. Management of hyperglycemia from epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) targeting T790M-mediated resistance

    OpenAIRE

    Villadolid, Jeryl; Ersek, Jennifer L.; Fong, Mei Ka; Sirianno, Lindsey; Story, Ellen S.

    2015-01-01

    Epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) patients are associated with sensitivity to small molecule tyrosine kinase inhibitors (TKIs) such as erlotinib, gefitinib, and afatinib. Although studies show an increased progression free survival (PFS) with use of EGFR TKIs in the first-line setting, most patients will develop resistance to therapy after the first 8-16 months. T790M is an acquired resistance mutation reported in 60-70% of patients who in...

  14. Inhibition of tyrosine kinase receptors by SU6668 promotes abnormal stromal development at the periphery of carcinomas

    OpenAIRE

    Farace, P; Galiè, M; F. Merigo; Daducci, A.; Calderan, L; Nicolato, E; Degrassi, A; Pesenti, E.; Sbarbati, A; Marzola, P.

    2009-01-01

    Dynamic contrast-enhanced (albumin-Gd-DTPA) magnetic resonance imaging, performed during 2 weeks of daily administration of an inhibitor of tyrosine kinase receptors (SU6668) in an HT-29 colon carcinoma model, revealed the onset of a hyper-enhancing rim, not observed in untreated tumours. To account for tissue heterogeneity in the quantitative analysis, we segmented tumours into three subunits automatically identified by cluster analysis of the enhancement curves using a k-means algorithm. Tr...

  15. Targeting receptor tyrosine kinases using monoclonal antibodies : the most specific tools for targeted-based cancer therapy

    OpenAIRE

    Shabani, Mehdi; Hojjat-Farsangi, Mohammad

    2015-01-01

    Receptor tyrosine kinases (RTKs) family is comprised of different cell surface glycoproteins. These enzymes participate and regulate vital processes such as cell proliferation, polarity, differentiation, cell to cell interactions, signaling, and cell survival. Dysregulation of RTKs contributes to the development of different types of tumors. RTKs deregulation in cancer has been reported for more than 30 RTKs. Due to critical roles of these molecules in cancer, the specific targeting of RTKs i...

  16. Gene expression analysis after receptor tyrosine kinase activation reveals new potential melanoma proteins

    International Nuclear Information System (INIS)

    Melanoma is an aggressive tumor with increasing incidence. To develop accurate prognostic markers and targeted therapies, changes leading to malignant transformation of melanocytes need to be understood. In the Xiphophorus melanoma model system, a mutated version of the EGF receptor Xmrk (Xiphophorus melanoma receptor kinase) triggers melanomagenesis. Cellular events downstream of Xmrk, such as the activation of Akt, Ras, B-Raf or Stat5, were also shown to play a role in human melanomagenesis. This makes the elucidation of Xmrk downstream targets a useful method for identifying processes involved in melanoma formation. Here, we analyzed Xmrk-induced gene expression using a microarray approach. Several highly expressed genes were confirmed by realtime PCR, and pathways responsible for their induction were revealed using small molecule inhibitors. The expression of these genes was also monitored in human melanoma cell lines, and the target gene FOSL1 was knocked down by siRNA. Proliferation and migration of siRNA-treated melanoma cell lines were then investigated. Genes with the strongest upregulation after receptor activation were FOS-like antigen 1 (Fosl1), early growth response 1 (Egr1), osteopontin (Opn), insulin-like growth factor binding protein 3 (Igfbp3), dual-specificity phosphatase 4 (Dusp4), and tumor-associated antigen L6 (Taal6). Interestingly, most genes were blocked in presence of a SRC kinase inhibitor. Importantly, we found that FOSL1, OPN, IGFBP3, DUSP4, and TAAL6 also exhibited increased expression levels in human melanoma cell lines compared to human melanocytes. Knockdown of FOSL1 in human melanoma cell lines reduced their proliferation and migration. Altogether, the data show that the receptor tyrosine kinase Xmrk is a useful tool in the identification of target genes that are commonly expressed in Xmrk-transgenic melanocytes and melanoma cell lines. The identified molecules constitute new possible molecular players in melanoma development

  17. Construction and Stable Expression of a Truncated Human Receptor Tyrosine Kinase Ror1 (Ror1-ECD).

    Science.gov (United States)

    Forouzesh, Flora; Tabarian, Samira Shakeri; Emami, Shaghayegh; Tehrani, Mahmood-Jeddi; Hadavi, Reza; Rabbani, Hodjattallah

    2012-01-01

    Expression of receptor tyrosine kinase Ror1 in a wide variety of cancers has emerged as a new era focusing on targeting this receptor in cancer therapy. Our preliminary results indicate the presence of a truncated transcript of Ror1 in tumor cells. The truncated Ror1 encompasses extracellular and transmembrane domains, lacking catalytic kinase domain (Ror1-ECD). As enzyme activity is highly dependent on the catalytic domain, we were wondering how this transcript and its encoded protein could play a possible role in tumorigenesis. To understand the function of this truncated transcript and whether or not the encoded protein translocates to the cell surface, we constructed a mammalian expression vector containing exon 1 to exon 8 of human Ror1 gene as a model system. The encoded protein by this construct covers the entire extracellular and transmembrane domains of Ror1. The Chinese Hamster Ovary Cell line (CHO) was used for transfection. Our results showed that this construct could express Ror1-ECD at protein level and also the protein could effectively translocate to the surface of transfected cells. Such model may suggest that a proportion of Ror1 molecules expressed by tumor cells are not full-length Ror1. This notion may be considered when applying flow cytometry using antibodies against Ror1 for screening of tumor cells in order to avoid any miscalculation in the number of Ror1 molecules expressed by tumor cells. Furthermore, such expression may bring about assumptions on functional roles of Ror1-ECD in tumorigenesis, which requires extensive functional studies. PMID:23408137

  18. Swim training of monosodium L-glutamate-obese mice improves the impaired insulin receptor tyrosine phosphorylation in pancreatic islets.

    Science.gov (United States)

    Miranda, Rosiane Aparecida; Branco, Renato Chaves Souto; Gravena, Clarice; Barella, Luiz Felipe; da Silva Franco, Claudinéia Conationi; Andreazzi, Ana Eliza; de Oliveira, Júlio Cezar; Picinato, Maria Cecília; de Freitas Mathias, Paulo Cezar

    2013-06-01

    The goal of the present study was to investigate changes on glucose homoeostasis and of the insulin receptor (IR) and insulin receptor substrate-1 (IRS-1) signalling in pancreatic islets from MSG-obese mice submitted to or not submitted to swim training. Swim training of 90-day-old MSG mice was used to evaluate whether signalling pathways of the IR and IRS-1 in islets are involved with the insulin resistance and glucose intolerance observed in this obese animal model. The results showed that IR tyrosine phosphorylation (pIR) was reduced by 42 % in MSG-obese mice (MSG, 6.7 ± 0.2 arbitrary units (a.u.); control, 11.5 ± 0.4 a.u.); on the other hand, exercise training increased pIR by 76 % in MSG mice without affecting control mice (MSG, 11.8 ± 0.3; control, 12.8 ± 0.2 a.u.). Although the treatment with MSG increased IRS-1 tyrosine phosphorylation (pIRS-1) by 96 % (MSG, 17.02 ± 0.6; control, 8.7 ± 0.2 a.u.), exercise training also increased it in both groups (control, 13.6 ± 0.1; MSG, 22.2 ± 1.1 a.u.). Current research shows that the practice of swim training increases the tyrosine phosphorylation of IRS-1 which can modulate the effect caused by obesity in insulin receptors. PMID:22983867

  19. Distinct Mechanisms of Receptor and Nonreceptor Tyrosine Kinase Activation by Reactive Oxygen Species in Vascular Smooth Muscle Cells: Role of Metalloprotease and Protein Kinase C-δ

    OpenAIRE

    Frank, Gerald D.; Mifune, Mizuo; Inagami, Tadashi; Ohba, Motoi; Sasaki, Terukatsu; Higashiyama, Shigeki; Dempsey, Peter J; Eguchi, Satoru

    2003-01-01

    Reactive oxygen species (ROS) are implicated in cardiovascular diseases. ROS, such as H2O2, act as second messengers to activate diverse signaling pathways. Although H2O2 activates several tyrosine kinases, including the epidermal growth factor (EGF) receptor, JAK2, and PYK2, in vascular smooth muscle cells (VSMCs), the intracellular mechanism by which ROS activate these tyrosine kinases remains unclear. Here, we identified two distinct signaling pathways required for receptor and nonreceptor...

  20. Inhibitory Activities of Epidermal Growth Factor Receptor Tyrosine Kinase-Targeted Dihydroxyisoflavone and Trihydroxydeoxybenzoin Derivatives on Sarcocystis neurona, Neospora caninum, and Cryptosporidium parvum Development

    OpenAIRE

    Gargala, G.; Baishanbo, A.; Favennec, L; François, A; Ballet, J J; Rossignol, J.-F.

    2005-01-01

    Several gene sequences of parasitic protozoa belonging to protein kinase gene families and epidermal growth factor (EGF)-like peptides, which act via binding to receptor tyrosine kinases of the EGF receptor (EGFR) family, appear to mediate host-protozoan interactions. As a clue to EGFR protein tyrosine kinase (PTK) mediation and a novel approach for identifying anticoccidial agents, activities against Sarcocystis neurona, Neospora caninum, and Cryptosporidium parvum grown in BM and HCT-8 cell...

  1. Protein tyrosine phosphatase receptor delta acts as a neuroblastoma tumor suppressor by destabilizing the aurora kinase a oncogene

    LENUS (Irish Health Repository)

    Meehan, Maria

    2012-02-05

    Abstract Background Protein tyrosine phosphatase receptor delta (PTPRD) is a member of a large family of protein tyrosine phosphatases which negatively regulate tyrosine phosphorylation. Neuroblastoma is a major childhood cancer arising from precursor cells of the sympathetic nervous system which is known to acquire deletions and alterations in the expression patterns of PTPRD, indicating a potential tumor suppressor function for this gene. The molecular mechanism, however, by which PTPRD renders a tumor suppressor effect in neuroblastoma is unknown. Results As a molecular mechanism, we demonstrate that PTPRD interacts with aurora kinase A (AURKA), an oncogenic protein that is over-expressed in multiple forms of cancer, including neuroblastoma. Ectopic up-regulation of PTPRD in neuroblastoma dephosphorylates tyrosine residues in AURKA resulting in a destabilization of this protein culminating in interfering with one of AURKA\\'s primary functions in neuroblastoma, the stabilization of MYCN protein, the gene of which is amplified in approximately 25 to 30% of high risk neuroblastoma. Conclusions PTPRD has a tumor suppressor function in neuroblastoma through AURKA dephosphorylation and destabilization and a downstream destabilization of MYCN protein, representing a novel mechanism for the function of PTPRD in neuroblastoma.

  2. Solution structure of the Shc SH2 domain complexed with a tyrosine-phosphorylated peptide from the T-cell receptor.

    OpenAIRE

    M. M. Zhou; Meadows, R P; Logan, T. M.; Yoon, H S; Wade, W S; Ravichandran, K S; Burakoff, S J; Fesik, S W

    1995-01-01

    She is a widely expressed adapter protein that plays an important role in signaling via a variety of cell surface receptors and has been implicated in coupling the stimulation of growth factor, cytokine, and antigen receptors to the Ras signaling pathway. She interacts with several tyrosine-phosphorylated receptors through its C-terminal SH2 domain, and one of the mechanisms of T-cell receptor-mediated Ras activation involves the interaction of the Shc SH2 domain with the tyrosine-phosphoryla...

  3. The EphB4 Receptor Tyrosine Kinase Promotes Lung Cancer Growth: A Potential Novel Therapeutic Target

    Science.gov (United States)

    Ferguson, Benjamin D.; Liu, Ren; Rolle, Cleo E.; Tan, Yi-Hung Carol; Krasnoperov, Valery; Kanteti, Rajani; Tretiakova, Maria S.; Cervantes, Gustavo M.; Hasina, Rifat; Hseu, Robyn D.; Iafrate, A. John; Karrison, Theodore; Ferguson, Mark K.; Husain, Aliya N.; Faoro, Leonardo; Vokes, Everett E.; Gill, Parkash S.; Salgia, Ravi

    2013-01-01

    Despite progress in locoregional and systemic therapies, patient survival from lung cancer remains a challenge. Receptor tyrosine kinases are frequently implicated in lung cancer pathogenesis, and some tyrosine kinase inhibition strategies have been effective clinically. The EphB4 receptor tyrosine kinase has recently emerged as a potential target in several other cancers. We sought to systematically study the role of EphB4 in lung cancer. Here, we demonstrate that EphB4 is overexpressed 3-fold in lung tumors compared to paired normal tissues and frequently exhibits gene copy number increases in lung cancer. We also show that overexpression of EphB4 promotes cellular proliferation, colony formation, and motility, while EphB4 inhibition reduces cellular viability in vitro, halts the growth of established tumors in mouse xenograft models when used as a single-target strategy, and causes near-complete regression of established tumors when used in combination with paclitaxel. Taken together, these data suggest an important role for EphB4 as a potential novel therapeutic target in lung cancer. Clinical trials investigating the efficacy of anti-EphB4 therapies as well as combination therapy involving EphB4 inhibition may be warranted. PMID:23844053

  4. Levels of active tyrosine kinase receptor determine the tumor response to Zalypsis

    International Nuclear Information System (INIS)

    Zalypsis® is a marine compound in phase II clinical trials for multiple myeloma, cervical and endometrial cancer, and Ewing’s sarcoma. However, the determinants of the response to Zalypsis are not well known. The identification of biomarkers for Zalypsis activity would also contribute to broaden the spectrum of tumors by selecting those patients more likely to respond to this therapy. Using in vitro drug sensitivity data coupled with a set of molecular data from a panel of sarcoma cell lines, we developed molecular signatures that predict sensitivity to Zalypsis. We verified these results in culture and in vivo xenograft studies. Zalypsis resistance was dependent on the expression levels of PDGFRα or constitutive phosphorylation of c-Kit, indicating that the activation of tyrosine kinase receptors (TKRs) may determine resistance to Zalypsis. To validate our observation, we measured the levels of total and active (phosphorylated) forms of the RTKs PDGFRα/β, c-Kit, and EGFR in a new panel of diverse solid tumor cell lines and found that the IC50 to the drug correlated with RTK activation in this new panel. We further tested our predictions about Zalypsis determinants for response in vivo in xenograft models. All cells lines expressing low levels of RTK signaling were sensitive to Zalypsis in vivo, whereas all cell lines except two with high levels of RTK signaling were resistant to the drug. RTK activation might provide important signals to overcome the cytotoxicity of Zalypsis and should be taken into consideration in current and future clinical trials

  5. Spontaneous Immunity Against the Receptor Tyrosine Kinase ROR1 in Patients with Chronic Lymphocytic Leukemia.

    Directory of Open Access Journals (Sweden)

    Mohammad Hojjat-Farsangi

    Full Text Available ROR1 is a receptor tyrosine kinase expressed in chronic lymphocytic leukemia (CLL and several other malignancies but absent in most adult normal tissues. ROR1 is considered an onco-fetal antigen. In the present study we analysed spontaneous humoral and cellular immunity against ROR1 in CLL patients.Antibodies against ROR1 were analysed in 23 patients and 20 healthy donors by ELISA and Western blot. Purified serum IgG from patients was tested for cytotoxicity against CLL cells using the MTT viability assay. A cellular immune response against ROR1 derived HLA-A2 restricted 9 aa and 16 aa long peptides were analysed using peptide loaded dendritic cells co-cultured with autologous T cells from CLL patients (n = 9 and healthy donors (n = 6. IFN-γ, IL-5 and IL-17A-secreting T cells were assessed by ELISPOT and a proliferative response using a H3-thymidine incorporation assay.The majority of CLL patients had antibodies against ROR1. Significantly higher titers of anti-ROR1 antibodies were noted in patients with non-progressive as compared to progressive disease. The extracellular membrane-close ROR1 KNG domain seemed to be an immunodominant epitope. Ten patients with high titers of anti-ROR1 binding antibodies were tested for cytotoxicity. Five of those had cytotoxic anti-ROR1 antibodies against CLL cells. ROR1-specific IFN-γ and IL-17A producing T cells could be detected in CLL patients, preferentially in non-progressive as compared to patients with progressive disease (p<0.05.ROR1 seemed to spontaneously induce a humoral as well as a T cell response in CLL patients. The data support the notion that ROR1 might be a specific neo-antigen and may serve as a target for immunotherapy.

  6. Tyrosine kinase activity of a chimeric insulin-like-growth-factor-1 receptor containing the insulin receptor C-terminal domain. Comparison with the tyrosine kinase activities of the insulin and insulin-like-growth-factor-1 receptors using a cell-free system.

    Science.gov (United States)

    Mothe, I; Tartare, S; Kowalski-Chauvel, A; Kaliman, P; Van Obberghen, E; Ballotti, R

    1995-03-15

    In a previous study, we showed that a chimeric insulin-like-growth-factor-1 (IGF-1) receptor, with the beta subunit C-terminal part of the insulin receptor was more efficient in stimulating glycogen synthesis and p44mapk activity compared to the wild-type IFG-1 receptor [Tartare, S., Mothe, I., Kowalski-Chauvel, A., Breittmayer, J.-P., Ballotti, R. & Van Obberghen, E. (1994) J. Biol. Chem. 269, 11449-11455]. These data indicate that the receptor C-terminal domain plays an important role in the transmission of biological effects. To understand the molecular basis of the differences in receptor specificity, we studied the characteristics of insulin, IGF-1 and chimeric receptor tyrosine kinase activities in a cell-free system. We found that, compared to wild-type insulin and IGF-1 receptors, the chimeric receptor showed a decrease in (a) autophosphorylation, (b) tyrosine kinase activity towards insulin receptor substrate-1 and the insulin receptor-(1142-1158)-peptide, and (c) the ability to activate phosphatidylinositol 3-kinase. However, for all the effects measured in a cell-free system, the chimeric receptor displayed an increased response to IGF-1 compared to the native IGF-1 receptor. Concerning the cation dependence of the tyrosine kinase activity, we showed that, at 10 mM Mg2+, the ligand-stimulated phosphorylation of poly(Glu80Tyr20) by both insulin receptor and chimeric receptor was increased by Mn2+. Conversely at 50 mM Mg2+, the chimeric receptor behaved like the IGF-1 receptor, since the presence of Mn2+ decreased the stimulatory effect of IGF-1 on their kinase activity. Furthermore, the Km of the chimeric receptor for ATP was increased compared to the wild-type receptors. These data demonstrate that the replacement of the C-terminal tail of the IGF-1 receptor by that of the insulin receptor has changed the receptor characteristics studied in a cell-free system. Our findings indicate that the C-terminal domain of the insulin receptor beta subunit plays a

  7. Distinct cellular properties of oncogenic KIT receptor tyrosine kinase mutants enable alternative courses of cancer cell inhibition.

    Science.gov (United States)

    Shi, Xiarong; Sousa, Leiliane P; Mandel-Bausch, Elizabeth M; Tome, Francisco; Reshetnyak, Andrey V; Hadari, Yaron; Schlessinger, Joseph; Lax, Irit

    2016-08-16

    Large genomic sequencing analysis as part of precision medicine efforts revealed numerous activating mutations in receptor tyrosine kinases, including KIT. Unfortunately, a single approach is not effective for inhibiting cancer cells or treating cancers driven by all known oncogenic KIT mutants. Here, we show that each of the six major KIT oncogenic mutants exhibits different enzymatic, cellular, and dynamic properties and responds distinctly to different KIT inhibitors. One class of KIT mutants responded well to anti-KIT antibody treatment alone or in combination with a low dose of tyrosine kinase inhibitors (TKIs). A second class of KIT mutants, including a mutant resistant to imatinib treatment, responded well to a combination of TKI with anti-KIT antibodies or to anti-KIT toxin conjugates, respectively. We conclude that the preferred choice of precision medicine treatments for cancers driven by activated KIT and other RTKs may rely on clear understanding of the dynamic properties of oncogenic mutants. PMID:27482095

  8. Dominant-negative inhibition of the Axl receptor tyrosine kinase suppresses brain tumor cell growth and invasion and prolongs survival

    Science.gov (United States)

    Vajkoczy, Peter; Knyazev, Pjotr; Kunkel, Andrea; Capelle, Hans-Holger; Behrndt, Sandra; von Tengg-Kobligk, Hendrik; Kiessling, Fabian; Eichelsbacher, Uta; Essig, Marco; Read, Tracy-Ann; Erber, Ralf; Ullrich, Axel

    2006-01-01

    Malignant gliomas remain incurable brain tumors because of their diffuse-invasive growth. So far, the genetic and molecular events underlying gliomagenesis are poorly understood. In this study, we have identified the receptor tyrosine kinase Axl as a mediator of glioma growth and invasion. We demonstrate that Axl and its ligand Gas6 are overexpressed in human glioma cell lines and that Axl is activated under baseline conditions. Furthermore, Axl is expressed at high levels in human malignant glioma. Inhibition of Axl signaling by overexpression of a dominant-negative receptor mutant (AXL-DN) suppressed experimental gliomagenesis (growth inhibition >85%, P 72 days). A detailed analysis of the distinct hallmarks of glioma pathology, such as cell proliferation, migration, and invasion and tumor angiogenesis, revealed that inhibition of Axl signaling interfered with cell proliferation (inhibition 30% versus AXL-WT), glioma cell migration (inhibition 90% versus mock and AXL-WT, P < 0.05), and invasion (inhibition 62% and 79% versus mock and AXL-WT, respectively; P < 0.05). This study describes the identification, functional manipulation, in vitro and in vivo validation, and preclinical therapeutic inhibition of a target receptor tyrosine kinase mediating glioma growth and invasion. Our findings implicate Axl in gliomagenesis and validate it as a promising target for the development of approaches toward a therapy of these highly aggressive but, as yet, therapy-refractory, tumors. PMID:16585512

  9. 8-THP-DHI analogs as potent Type I dual TIE-2/VEGF-R2 receptor tyrosine kinase inhibitors.

    Science.gov (United States)

    Hudkins, Robert L; Zulli, Allison L; Underiner, Ted L; Angeles, Thelma S; Aimone, Lisa D; Meyer, Sheryl L; Pauletti, Daniel; Chang, Hong; Fedorov, Elena V; Almo, Steven C; Fedorov, Alexander A; Ruggeri, Bruce A

    2010-06-01

    A novel series of 8-(2-tetrahydropyranyl)-12,13-dihydroindazolo[5,4-a]pyrrolo[3,4-c]carbazoles (THP-DHI) was synthesized and evaluated as dual TIE-2 and VEGF-R2 receptor tyrosine kinase inhibitors. Development of the structure-activity relationships (SAR) with the support of X-ray crystallography led to identification of 7f and 7g as potent, selective dual TIE-2/VEGF-R2 inhibitors with excellent cellular potency and acceptable pharmacokinetic properties. Compounds 7f and 7g were orally active in tumor models with no observed toxicity. PMID:20430619

  10. In situ autoradiography and ligand-dependent tyrosine kinase activity reveal insulin receptors and insulin-like growth factor I receptors in prepancreatic chicken embryos

    International Nuclear Information System (INIS)

    We previously reported specific cross-linking of 125I-labeled insulin and 125I-labeled insulin-like growth factor I (IGF-I) to the alpha subunit of their respective receptors in chicken embryos of 20 somites and older. To achieve adequate sensitivity and localize spatially the receptors in younger embryos, we adapted an autoradiographic technique using whole-mounted chicken blastoderms. Insulin receptors and IGF-I receptors were expressed and could be localized as early as gastrulation, before the first somite is formed. Relative density was analyzed by a computer-assisted image system, revealing overall slightly higher binding of IGF-I than of insulin. Structures rich in both types of receptors were predominantly of ectodermal origin: Hensen's node in gastrulating embryos and neural folds, neural tube and optic vesicles during neurulation. The signal transduction capability of the receptors in early organogenesis was assessed by their ability to phosphorylate the exogenous substrate poly(Glu80Tyr20). Ligand-dependent tyrosine phosphorylation was demonstrable with both insulin and IGF-I in glycoprotein-enriched preparations from embryos at days 2 through 6 of embryogenesis. There was a developmentally regulated change in ligand-dependent tyrosine kinase activity, with a sharp increase from day 2 to day 4, in contrast with a small increase in the ligand binding. Binding of 125I-labeled IGF-I was, with the solubilized receptors, severalfold higher than binding of 125I-labeled insulin. However, the insulin-dependent phosphorylation was as high as the IGF-I-dependent phosphorylation at each developmental stage

  11. Mer receptor tyrosine kinase is a therapeutic target in pre–B-cell acute lymphoblastic leukemia

    OpenAIRE

    Linger, Rachel M.A.; Lee-Sherick, Alisa B.; DeRyckere, Deborah; Cohen, Rebecca A.; Jacobsen, Kristen M.; McGranahan, Amy; Brandão, Luis N.; Winges, Amanda; Sawczyn, Kelly K.; Liang, Xiayuan; Keating, Amy K.; Tan, Aik Choon; Earp, H. Shelton; Graham, Douglas K.

    2013-01-01

    Mer tyrosine kinase is aberrantly expressed in ∼30% of pediatric pre–B-ALL patients, including most patients with an E2A-PBX1 translocation.Mer inhibition decreased B-ALL cell survival signal transduction, caused chemosensitization, and prolonged survival in a xenograft model.

  12. Domains of the growth hormone receptor required for association and activation of JAK2 tyrosine kinase

    DEFF Research Database (Denmark)

    VanderKuur, J A; Wang, X; Zhang, L;

    1994-01-01

    , and that tyrosines in the N-terminal half of the cytoplasmic domain of the GHR are phosphorylated by JAK2. The finding that a specific interaction with the C-terminal half of GHR appears to be necessary for p97 phosphorylation indicates that while JAK2 activation may be necessary for a full biological response to GH...

  13. Sleeping Beauty Transposition of Chimeric Antigen Receptors Targeting Receptor Tyrosine Kinase-Like Orphan Receptor-1 (ROR1 into Diverse Memory T-Cell Populations.

    Directory of Open Access Journals (Sweden)

    Drew C Deniger

    Full Text Available T cells modified with chimeric antigen receptors (CARs targeting CD19 demonstrated clinical activity against some B-cell malignancies. However, this is often accompanied by a loss of normal CD19+ B cells and humoral immunity. Receptor tyrosine kinase-like orphan receptor-1 (ROR1 is expressed on sub-populations of B-cell malignancies and solid tumors, but not by healthy B cells or normal post-partum tissues. Thus, adoptive transfer of T cells specific for ROR1 has potential to eliminate tumor cells and spare healthy tissues. To test this hypothesis, we developed CARs targeting ROR1 in order to generate T cells specific for malignant cells. Two Sleeping Beauty transposons were constructed with 2nd generation ROR1-specific CARs signaling through CD3ζ and either CD28 (designated ROR1RCD28 or CD137 (designated ROR1RCD137 and were introduced into T cells. We selected for T cells expressing CAR through co-culture with γ-irradiated activating and propagating cells (AaPC, which co-expressed ROR1 and co-stimulatory molecules. Numeric expansion over one month of co-culture on AaPC in presence of soluble interleukin (IL-2 and IL-21 occurred and resulted in a diverse memory phenotype of CAR+ T cells as measured by non-enzymatic digital array (NanoString and multi-panel flow cytometry. Such T cells produced interferon-γ and had specific cytotoxic activity against ROR1+ tumors. Moreover, such cells could eliminate ROR1+ tumor xenografts, especially T cells expressing ROR1RCD137. Clinical trials will investigate the ability of ROR1-specific CAR+ T cells to specifically eliminate tumor cells while maintaining normal B-cell repertoire.

  14. Sulfated Tyrosines Contribute to the Formation of the C5a Docking Site of the Human C5a Anaphylatoxin Receptor

    Science.gov (United States)

    Farzan, Michael; Schnitzler, Christine E.; Vasilieva, Natalya; Leung, Doris; Kuhn, Jens; Gerard, Craig; Gerard, Norma P.; Choe, Hyeryun

    2001-01-01

    The complement anaphylatoxin C5a and its seven-transmembrane segment (7TMS) receptor play an important role in host defense and in a number of inflammation-associated pathologies. The NH2-terminal domain of the C5a receptor (C5aR/CD88) contributes substantially to its ability to bind C5a. Here we show that the tyrosines at positions 11 and 14 of the C5aR are posttranslationally modified by the addition of sulfate groups. The sulfate moieties of each of these tyrosines are critical to the ability of the C5aR to bind C5a and to mobilize calcium. A C5aR variant lacking these sulfate moieties efficiently mobilized calcium in response to a small peptide agonist, but not to C5a, consistent with a two-site model of ligand association in which the tyrosine-sulfated region of the C5aR mediates the initial docking interaction. A peptide based on the NH2 terminus of the C5aR and sulfated at these two tyrosines, but not its unsulfated analogue or a doubly sulfated control peptide, partially inhibited C5a association with its receptor. These observations clarify structural and mutagenic studies of the C5a/C5aR association and suggest that related 7TMS receptors are also modified by functionally important sulfate groups on their NH2-terminal tyrosines. PMID:11342590

  15. Involvement of receptor tyrosine kinase Tyro3 in amyloidogenic APP processing and β-amyloid deposition in Alzheimer's disease models.

    Directory of Open Access Journals (Sweden)

    Yan Zheng

    Full Text Available Alzheimer's disease (AD is the most common progressive neurodegenerative disease known to humankind. It is characterized by brain atrophy, extracellular amyloid plaques, and intracellular neurofibril tangles. β-Amyloid cascade is considered the major causative player in AD. Up until now, the mechanisms underlying the process of Aβ generation and accumulation in the brain have not been well understood. Tyro3 receptor belongs to the TAM receptor subfamily of receptor protein tyrosine kinases (RPTKs. It is specifically expressed in the neurons of the neocortex and hippocampus. In this study, we established a cell model stably expressing APPswe mutants and producing Aβ. We found that overexpression of Tyro3 receptor in the cell model significantly decreased Aβ generation and also down-regulated the expression of β-site amyloid precursor protein cleaving enzyme (BACE1. However, the effects of Tyro3 were inhibited by its natural ligand, Gas6, in a concentration-dependent manner. In order to confirm the role of Tyro3 in the progression of AD development, we generated an AD transgenic mouse model accompanied by Tyro3 knockdown. We observed a significant increase in the number of amyloid plaques in the hippocampus in the mouse model. More plaque-associated clusters of astroglia were also detected. The present study may help researchers determine the role of Tyro3 receptor in the neuropathology of AD.

  16. Proliferation of Ewing sarcoma cell lines is suppressed by the receptor tyrosine kinase inhibitors gefitinib and vandetanib

    Directory of Open Access Journals (Sweden)

    Åman Pierre

    2008-01-01

    Full Text Available Abstract Background Tyrosine kinase inhibitors (TKIs have gained much attention in recent years as targeted agents for the treatment of a wide range of human cancers. We have investigated the effect of the TKIs gefitinib and vandetanib on tumor cell lines derived from Ewing sarcoma, a highly malignant tumor affecting bone and soft tissue in children and young adults. Gefitinib is an inhibitor of epidermal growth factor receptor tyrosine kinase activity (EGFR and vandetanib selectively targets vascular endothelial growth factor receptor-2 (VEGFR-2 with additional activity against VEGFR-3, EGFR and RET kinase receptors. Results Two Ewing sarcoma cell lines investigated showed high levels of nuclear EGFR expression as well as moderate expression in plasma membrane and cytoplasm. When treated with concentrations of 5 μM and more of either gefitinib or vandetanib, we observed a significant decrease in cell proliferation. However, there were no detectable changes in p44/42 MAPK and Akt-1 phosphorylation, or in the expression of cyclin D1 or c-Myc following gefitinib or vandetanib treatment. Conclusion We conclude that Ewing sarcoma tumor cell proliferation is not highly sensitive to inhibition of EGFR signaling alone or the simultaneous inhibition of VEGFR receptors, EGFR and RET kinase. Decreased tumor cell proliferation could be achieved with gefitinib and vandetanib, but only at higher doses where non-specific effects of the compounds may be overriding. As Ewing tumor cells do not seem to depend on EGFR and VEGFR pathways for survival, other key factors in the cellular signaling of Ewing sarcoma should be targeted in order to obtain a potent therapeutic response.

  17. The Role of Epidermal Growth Factor Receptor Mutations and Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors in the Treatment of Lung Cancer

    OpenAIRE

    Shih-Chieh Chang; Jin-Yuan Shih; Cheng-Yu Chang

    2011-01-01

    Lung cancer is the leading cause of cancer-related deaths worldwide. Non-small-cell lung cancer (NSCLC) cases comprise approximately 85% of the lung cancer cases. Before the era of target therapy, platinum-based doublet chemotherapy only led to a median survival of 8–9 months and a one-year survival of 30%–40% in patients with advanced NSCLC. In July 2002, gefitinib, a small-molecule epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), was approved for the treatment of patie...

  18. The Mertk Receptor Tyrosine Kinase Promotes T-B interaction Stimulated by IgD B-cell Receptor Cross-linking

    OpenAIRE

    Shao, Wen-Hai; Zhen, Yuxuan; Finkelman, Fred D.; Cohen, Philip L.

    2014-01-01

    The Mertk receptor tyrosine kinase facilitates macrophage and DC apoptotic-cell clearance and regulates immune tolerance. Mertk may also contribute to B-cell activation, because Mertk-KO mice fail to develop autoantibodies when allo-activated by T cells. We investigated this possibility with a well-characterized model in which injection of mice with goat anti-IgD antibody causes membrane IgD cross-linking that induces T-independent B cell activation and antigen presentation to T cells. Goat a...

  19. Protein-protein interactions in crystals of the human receptor-type protein tyrosine phosphatase ICA512 ectodomain.

    Directory of Open Access Journals (Sweden)

    María E Primo

    Full Text Available ICA512 (or IA-2 is a transmembrane protein-tyrosine phosphatase located in secretory granules of neuroendocrine cells. Initially, it was identified as one of the main antigens of autoimmune diabetes. Later, it was found that during insulin secretion, the cytoplasmic domain of ICA512 is cleaved and relocated to the nucleus, where it stimulates the transcription of the insulin gene. The role of the other parts of the receptor in insulin secretion is yet to be unveiled. The structures of the intracellular pseudocatalytic and mature extracellular domains are known, but the transmembrane domain and several intracellular and extracellular parts of the receptor are poorly characterized. Moreover the overall structure of the receptor remains to be established. We started to address this issue studying by X-ray crystallography the structure of the mature ectodomain of ICA512 (ME ICA512 and variants thereof. The variants and crystallization conditions were chosen with the purpose of exploring putative association interfaces, metal binding sites and all other structural details that might help, in subsequent works, to build a model of the entire receptor. Several structural features were clarified and three main different association modes of ME ICA512 were identified. The results provide essential pieces of information for the design of new experiments aimed to assess the structure in vivo.

  20. Investigation of the vitamin D receptor gene (VDR) and its interaction with protein tyrosine phosphatase, non-receptor type 2 gene (PTPN2) on risk of islet autoimmunity and type 1 diabetes : The Diabetes Autoimmunity Study in the Young (DAISY)

    NARCIS (Netherlands)

    Frederiksen, B.; Liu, E.; Romanos, J.; Steck, A. K.; Yin, X.; Kroehl, M.; Fingerlin, T. E.; Erlich, H.; Eisenbarth, G. S.; Rewers, M.; Norris, J. M.

    2013-01-01

    The present study investigated the association between variants in the vitamin D receptor gene (VDR) and protein tyrosine phosphatase, non-receptor type 2 gene (PTPN2), as well as an interaction between VDR and PTPN2 and the risk of islet autoimmunity (IA) and progression to type 1 diabetes (T1D). T

  1. A receptor tyrosine kinase inhibitor, Tyrphostin A9 induces cancer cell death through Drp1 dependent mitochondria fragmentation

    International Nuclear Information System (INIS)

    Highlights: → We screened and identified Tyrphostin A9, a receptor tyrosine kinase inhibitor as a strong mitochondria fission inducer. → Tyrphostin A9 treatment promotes mitochondria dysfunction and contributes to cytotoxicity in cancer cells. → Tyrphostin A9 induces apoptotic cell death through a Drp1-mediated pathway. → Our studies suggest that Tyrphostin A9 induces mitochondria fragmentation and apoptotic cell death via Drp1 dependently. -- Abstract: Mitochondria dynamics controls not only their morphology but also functions of mitochondria. Therefore, an imbalance of the dynamics eventually leads to mitochondria disruption and cell death. To identify specific regulators of mitochondria dynamics, we screened a bioactive chemical compound library and selected Tyrphostin A9, a tyrosine kinase inhibitor, as a potent inducer of mitochondrial fission. Tyrphostin A9 treatment resulted in the formation of fragmented mitochondria filament. In addition, cellular ATP level was decreased and the mitochondrial membrane potential was collapsed in Tyr A9-treated cells. Suppression of Drp1 activity by siRNA or over-expression of a dominant negative mutant of Drp1 inhibited both mitochondrial fragmentation and cell death induced by Tyrpohotin A9. Moreover, treatment of Tyrphostin A9 also evoked mitochondrial fragmentation in other cells including the neuroblastomas. Taken together, these results suggest that Tyrphostin A9 induces Drp1-mediated mitochondrial fission and apoptotic cell death.

  2. Analysis of Somatic Mutations in Cancer: Molecular Mechanisms of Activation in the ErbB Family of Receptor Tyrosine Kinases

    International Nuclear Information System (INIS)

    The ErbB/EGFR/HER family of kinases consists of four homologous receptor tyrosine kinases which are important regulatory elements in many cellular processes, including cell proliferation, differentiation, and migration. Somatic mutations in, or over-expression of, the ErbB family is found in many cancers and is correlated with a poor prognosis; particularly, clinically identified mutations found in non-small-cell lung cancer (NSCLC) of ErbB1 have been shown to increase its basal kinase activity and patients carrying these mutations respond remarkably to the small tyrosine kinase inhibitor gefitinib. Here, we analyze the potential effects of the currently catalogued clinically identified mutations in the ErbB family kinase domains on the molecular mechanisms of kinase activation. Recently, we identified conserved networks of hydrophilic and hydrophobic interactions characteristic to the active and inactive conformation, respectively. Here, we show that the clinically identified mutants influence the kinase activity in distinctive fashion by affecting the characteristic interaction networks

  3. The role of oestrogen receptor {alpha} in human thyroid cancer: contributions from coregulatory proteins and the tyrosine kinase receptor HER2.

    LENUS (Irish Health Repository)

    Kavanagh, Dara O

    2012-02-01

    Epidemiological, clinical, and molecular studies suggest a role for oestrogen in thyroid cancer. How oestrogen mediates its effects and the consequence of it on clinical outcome has not been fully elucidated. The participation of coregulatory proteins in modulating oestrogen receptor (ER) function and input of crosstalk with the tyrosine kinase receptor HER2 was investigated. Oestrogen induced cell proliferation in the follicular thyroid cancer (FTC)-133 cells, but not in the anaplastic 8305C cell line. Knockdown of the coactivator steroid receptor coactivator (SRC)-1 inhibited FTC-133 basal, but not oestrogen induced, cell proliferation. Oestrogen also increased protein expression of SRC-1 and the ER target gene cyclin D1 in the FTC-133 cell line. ERalpha, ERbeta, the coregulatory proteins SRC-1 and nuclear corepressor (NCoR), and the tyrosine kinase receptor HER2 were localised by immunohistochemistry and immnofluorescence in paraffin-embedded tissue from thyroid tumour patients (n=111). ERalpha was colocalised with both SRC-1 and NCoR to the nuclei of the tumour epithelial cells. Expression of ERalpha and NCoR was found predominantly in non-anaplastic tumours and was significantly associated with well-differentiated tumours and reduced incidence of disease recurrence. In non-anaplastic tumours, HER2 was significantly associated with SRC-1, and these proteins were associated with poorly differentiated tumours, capsular invasion and disease recurrence. Totally, 87% of anaplastic tumours were positive for SRC-1. Kaplan-Meier estimates of disease-free survival indicated that in thyroid cancer, SRC-1 strongly correlates with reduced disease-free survival (P<0.001), whereas NCoR predicted increased survival (P<0.001). These data suggest opposing roles for the coregulators SRC-1 and NCoR in thyroid tumour progression.

  4. δ-Opioid receptor-stimulated Akt signaling in neuroblastoma x glioma (NG108-15) hybrid cells involves receptor tyrosine kinase-mediated PI3K activation

    International Nuclear Information System (INIS)

    δ-Opioid receptor (DOR) agonists possess cytoprotective properties, an effect associated with activation of the 'pro-survival' kinase Akt. Here we delineate the signal transduction pathway by which opioids induce Akt activation in neuroblastoma x glioma (NG108-15) hybrid cells. Exposure of the cells to both [D-Pen2,5]enkephalin and etorphine resulted in a time- and dose-dependent increase in Akt activity, as measured by means of an activation-specific antibody recognizing phosphoserine-473. DOR-mediated Akt signaling is blocked by the opioid antagonist naloxone and involves inhibitory Gi/o proteins, because pre-treatment with pertussis toxin, but not over-expression of the Gq/11 scavengers EBP50 and GRK2-K220R, prevented this effect. Further studies with Wortmannin and LY294002 revealed that phophoinositol-3-kinase (PI3K) plays a central role in opioid-induced Akt activation. Opioids stimulate Akt activity through transactivation of receptor tyrosine kinases (RTK), because pre-treatment of the cells with inhibitors for neurotrophin receptor tyrosine kinases (AG879) and the insulin-like growth factor receptor IGF-1 (AG1024), but not over-expression of the Gβγ scavenger phosducin, abolished this effect. Activated Akt translocates to the nuclear membrane, where it promotes GSK3 phosphorylation and prevents caspase-3 cleavage, two key events mediating inhibition of cell apoptosis and enhancement of cell survival. Taken together, these results demonstrate that in NG108-15 hybrid cells DOR agonists possess cytoprotective properties mediated by activation of the RTK/PI3K/Akt signaling pathway.

  5. The viral G protein-coupled receptor ORF74 unmasks phospholipase C signaling of the receptor tyrosine kinase IGF-1R.

    Science.gov (United States)

    de Munnik, Sabrina M; van der Lee, Rosan; Velders, Daniëlle M; van Offenbeek, Jody; Smits-de Vries, Laura; Leurs, Rob; Smit, Martine J; Vischer, Henry F

    2016-06-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) encodes the constitutively active G protein-coupled receptor ORF74, which is expressed on the surface of infected host cells and has been linked to the development of the angioproliferative tumor Kaposi's sarcoma. Furthermore, the insulin-like growth factor (IGF)-1 receptor, a receptor tyrosine kinase, also plays an essential role in Kaposi's sarcoma growth and survival. In this study we examined the effect of the constitutively active viral receptor ORF74 on human IGF-1R signaling. Constitutive and CXCL1-induced ORF74 signaling did not transactivate IGF-1R. In contrast, IGF-1 stimulated phospholipase C (PLC) activation in an ORF74-dependent manner without affecting chemokine binding to ORF74. Inhibition of constitutive ORF74 activity by mutagenesis or the inverse agonist CXCL10, or neutralizing IGF-1R with an antibody or silencing IGF-1R expression using siRNA inhibited PLC activation by IGF-1. Transactivation of ORF74 in response to IGF-1 occurred independently of Src, PI3K, and secreted ORF74 ligands. Furthermore, tyrosine residues in the carboxyl-terminus and intracellular loop 2 of ORF74 are not essential for IGF-1-induced PLC activation. Interestingly, PLC activation in response to IGF-1 is specific for ORF74 as IGF-1 was unable to activate PLC in cells expressing the constitutively active human cytomegalovirus (HCMV)-encoded GPCR US28. Interestingly, IGF-1 does not induce β-arrestin recruitment to ORF74. The proximity ligation assay revealed close proximity between ORF74 and IGF-1R on the cell surface, but a physical interaction was not confirmed by co-immunoprecipitation. Unmasking IGF-1R signaling to PLC in response to IGF-1 is a previously unrecognized action of ORF74. PMID:26931381

  6. {delta}-Opioid receptor-stimulated Akt signaling in neuroblastoma x glioma (NG108-15) hybrid cells involves receptor tyrosine kinase-mediated PI3K activation

    Energy Technology Data Exchange (ETDEWEB)

    Heiss, Anika; Ammer, Hermann [Institute of Pharmacology, Toxicology and Pharmacy Ludwig-Maximilians-University of Munich Koeniginstrasse 16 80539 Muenchen Federal Republic of Germany (Germany); Eisinger, Daniela A., E-mail: eisinger@pharmtox.vetmed.uni-muenchen.de [Institute of Pharmacology, Toxicology and Pharmacy Ludwig-Maximilians-University of Munich Koeniginstrasse 16 80539 Muenchen Federal Republic of Germany (Germany)

    2009-07-15

    {delta}-Opioid receptor (DOR) agonists possess cytoprotective properties, an effect associated with activation of the 'pro-survival' kinase Akt. Here we delineate the signal transduction pathway by which opioids induce Akt activation in neuroblastoma x glioma (NG108-15) hybrid cells. Exposure of the cells to both [D-Pen{sup 2,5}]enkephalin and etorphine resulted in a time- and dose-dependent increase in Akt activity, as measured by means of an activation-specific antibody recognizing phosphoserine-473. DOR-mediated Akt signaling is blocked by the opioid antagonist naloxone and involves inhibitory G{sub i/o} proteins, because pre-treatment with pertussis toxin, but not over-expression of the G{sub q/11} scavengers EBP50 and GRK2-K220R, prevented this effect. Further studies with Wortmannin and LY294002 revealed that phophoinositol-3-kinase (PI3K) plays a central role in opioid-induced Akt activation. Opioids stimulate Akt activity through transactivation of receptor tyrosine kinases (RTK), because pre-treatment of the cells with inhibitors for neurotrophin receptor tyrosine kinases (AG879) and the insulin-like growth factor receptor IGF-1 (AG1024), but not over-expression of the G{beta}{gamma} scavenger phosducin, abolished this effect. Activated Akt translocates to the nuclear membrane, where it promotes GSK3 phosphorylation and prevents caspase-3 cleavage, two key events mediating inhibition of cell apoptosis and enhancement of cell survival. Taken together, these results demonstrate that in NG108-15 hybrid cells DOR agonists possess cytoprotective properties mediated by activation of the RTK/PI3K/Akt signaling pathway.

  7. Tyrosine-specific protein kinase activity is associated with the purified insulin receptor.

    OpenAIRE

    Kasuga, M.; Fujita-Yamaguchi, Y; Blithe, D L; Kahn, C. R.

    1983-01-01

    Highly purified human placental insulin receptors were obtained by sequential affinity chromatography on wheat germ agglutinin and insulin-agarose. The preparation had an insulin binding capacity of 4,700 pmol/mg of protein approaching theoretical purity. The purified receptor revealed three major bands of Mr 135,000, 95,000, and 52,000 in NaDodSO4/polyacrylamide gel electrophoresis after reduction by dithiothreitol. All three bands were immunoprecipitated by anti-insulin-receptor antibodies....

  8. Expression of a truncated receptor protein tyrosine phosphatase kappa in the brain of an adult transgenic mouse

    DEFF Research Database (Denmark)

    Shen, P; Canoll, P D; Sap, J;

    1999-01-01

    Receptor protein tyrosine phosphatases (RPTPs) comprise a family of proteins that feature intracellular phosphatase domains and an ectodomain with putative ligand-binding motifs. Several RPTPs are expressed in the brain, including RPTP-kappa which participates in homophilic cell-cell interactions...... developmental processes such as axonal growth and target recognition, as has been demonstrated for certain Drosophila RPTPs. The brain distribution of RPTP-kappa-expressing cells has not been determined, however. In a gene-trap mouse model with a beta-gal+neo (beta-geo) insertion in the endogenous RPTP......-kappa gene, the consequent loss of RPTP-kappa's enzymatic activity does not produce any obvious phenotypic defects [W.C. Skarnes, J.E. Moss, S.M. Hurtley, R.S.P. Beddington, Capturing genes encoding membrane and secreted proteins important for mouse development, Proc. Natl. Acad. Sci. U.S.A. 92 (1995) 6592...

  9. SRC-DEPENDENT PHOSPHORYLATION OF THE EPIDERMAL GROWTH FACTOR RECEPTOR ON TYROSINE 845 IS REQUIRED FOR ZINC-INDUCED RAS ACTIVATION

    Science.gov (United States)

    Src-dependent Phosphorylation of the Epidermal Growth Factor Receptor on Tyrosine 845 Is Required for Zinc-induced Ras ActivationWeidong Wu 1 , Lee M. Graves 2 , Gordon N. Gill 3 , Sarah J. Parsons 4 , and James M. Samet 51 Center for Environmental Medicine and Lung Biolo...

  10. Inhibition of corneal neovascularization with new Tyrosine Kinase Inhibitors targeting vascular endothelial growth factor receptors: Sunitinib malate and Sorafenib

    Directory of Open Access Journals (Sweden)

    Delnia Arshadi

    2007-06-01

    Full Text Available Corneal neovascularization (NV is a significant, sight-threatening, complication of many ocular surface disorders. Presence of new vessels in cornea can compromise clarity and thus vision. The data supporting a causal role for vascular endothelial growth factor (VEGF in corneal NV are extensive. Inhibition of VEGF remains as a main strategy for treating corneal NV. There is a growing body of evidence that corneal NV can be reduced by using anti-VEGF agents. Sunitinib malate and Sorafenib are new orally bio-available anti-angiogenic agents undergoing tests of efficacy in the treatment of various types of cancers. The main mechanism of these drugs is inhibiting angiogenesis by diminishing signaling through VEGF receptor1 (VEGFR1, VEGFR2, and platelet-derived growth factor receptors. Since VEGF exerts its angiogenic effects through tyrosine kinase receptors in cornea, any mechanisms which reduce VEGF signaling may inhibit corneal NV or at least attenuate it. Based on this fact we herein hypothesize that Sunitinib malate and Sorafenib can be prepared in topical form and be used in corneal neovascularization states. These approaches offer new hope for the successful treatment of corneal NV. Further investigations in animal models are needed to place these two drugs alongside corneal NV therapeutics.

  11. Tyrosine receptor kinase B silencing inhibits anoikis‑resistance and improves anticancer efficiency of sorafenib in human renal cancer cells.

    Science.gov (United States)

    Zhang, Peng; Xing, Zengshu; Li, Xuechao; Song, Yarong; Zhao, Jun; Xiao, Yajun; Xing, Yifei

    2016-04-01

    Renal cell carcinoma (RCC) is the most common solid neoplasm of adult kidney, and the major treatment for metastatic RCC (mRCC) is molecular targeted therapy. Sorafenib, as a multi-targeted tyrosine kinase inhibitor (TKI), has significantly improved clinical outcomes of mRCC patients. However, complete or long-term remissions are rarely achieved due to intolerance to dose-related adverse effects. It is therefore, necessary to explore novel target molecules for treatment or to enhance the therapeutic efficiency of present TKI for mRCC treatment. Anoikis is a specific type of apoptosis that plays a vital physiological role in regulating tissue homoeostasis. Anoikis-resistance is of critical importance for metastasis of various human cancers including mRCC. However, the precise mechanisms on anoikis-resistance in mRCC are still unclear. Tyrosine receptor kinase B (TrkB) belongs to the Trk family of neurotrophin receptors. Previous investigations have implied that activation or overexpression of TrkB promoted proliferation, survival, angiogenesis, anoikis-resistance and metastasis in human cancers. Yet, the correlation between TrkB and anoikis-resistance in mRCC has rarely been reported. The aim of the present study was to explore the impact of TrkB on anoikis-resistance and targeted therapy in mRCC. Our data revealed that anoikis-resistant ACHN cells presented with tolerance to detachment-induced apoptosis, excessive proliferation and aggressive invasion, accompanied by upregulation of TrkB expression in contrast to parental cells. Furthermore, TrkB silencing caused apoptosis, inhibited proliferation, retarded invasion as well as improved anticancer efficiency of sorafenib in anoikis-resistant ACHN cells through inactivation of PI3K/Akt and MEK/ERK pathways. Our data may offer a novel potential therapeutic strategy for mRCC. PMID:26820170

  12. The receptor protein tyrosine phosphatase (RPTP)β/ζ is expressed in different subtypes of human breast cancer

    International Nuclear Information System (INIS)

    Increasing evidence suggests mutations in human breast cancer cells that induce inappropriate expression of the 18-kDa cytokine pleiotrophin (PTN, Ptn) initiate progression of breast cancers to a more malignant phenotype. Pleiotrophin signals through inactivating its receptor, the receptor protein tyrosine phosphatase (RPTP)β/ζ, leading to increased tyrosine phosphorylation of different substrate proteins of RPTPβ/ζ, including β-catenin, β-adducin, Fyn, GIT1/Cat-1, and P190RhoGAP. PTN signaling thus has wide impact on different important cellular systems. Recently, PTN was found to activate anaplastic lymphoma kinase (ALK) through the PTN/RPTPβ/ζ signaling pathway; this discovery potentially is very important, since constitutive ALK activity of nucleophosmin (NPM)-ALK fusion protein is causative of anaplastic large cell lymphomas, and, activated ALK is found in other malignant cancers. Recently ALK was identified in each of 63 human breast cancers from 22 subjects. We now demonstrate that RPTPβ/ζ is expressed in each of these same 63 human breast cancers that previously were found to express ALK and in 10 additional samples of human breast cancer. RPTPβ/ζ furthermore was localized not only in its normal association with the cell membrane but also scattered in cytoplasm and in nuclei in different breast cancer cells and, in the case of infiltrating ductal carcinomas, the distribution of RPTPβ/ζ changes as the breast cancer become more malignant. The data suggest that the PTN/RPTPβ/ζ signaling pathway may be constitutively activated and potentially function to constitutively activate ALK in human breast cancer

  13. Effects of angiopoietins-1 and -2 on the receptor tyrosine kinase Tie2 are differentially regulated at the endothelial cell surface

    OpenAIRE

    Hansen, Tania M.; Singh, Harprit; Tahir, Tariq A.; Nicholas P J Brindle

    2010-01-01

    Angiopoietin-1 (Ang1) and Ang2 are ligands for the receptor tyrosine kinase Tie2. Structural data suggest that the two ligands bind Tie2 similarly. However, in endothelial cells Ang1 activates Tie2 whereas Ang2 can act as an apparent antagonist. In addition, each ligand exhibits distinct kinetics of release following binding. These observations suggest that additional factors influence function and binding of angiopoietins with receptors in the cellular context. Previous work has shown that A...

  14. Sensitivities to various epidermal growth factor receptor-tyrosine kinase inhibitors of uncommon epidermal growth factor receptor mutations L861Q and S768I: What is the optimal epidermal growth factor receptor-tyrosine kinase inhibitor?

    Science.gov (United States)

    Banno, Eri; Togashi, Yosuke; Nakamura, Yu; Chiba, Masato; Kobayashi, Yoshihisa; Hayashi, Hidetoshi; Terashima, Masato; de Velasco, Marco A; Sakai, Kazuko; Fujita, Yoshihiko; Mitsudomi, Tetsuya; Nishio, Kazuto

    2016-08-01

    Most patients with non-small cell lung cancer (NSCLC) harboring common epidermal growth factor receptor (EGFR) mutations, such as deletions in exon 19 or the L858R mutation in exon 21, respond dramatically to EGFR tyrosine kinase inhibitors (EGFR-TKI), and their sensitivities to various EGFR-TKI have been well characterized. Our previous article showed the in vitro sensitivities of EGFR exon 18 mutations to EGFR-TKI, but little information regarding the sensitivities of other uncommon EGFR mutations is available. First, stable transfectant Ba/F3 cell lines harboring EGFR L858R (Ba/F3-L858R), L861Q (Ba/F3-L861Q) or S768I (Ba/F3-S768I) mutations were created and their drug sensitivities to various EGFR-TKI were examined. Both the Ba/F3-L861Q and Ba/F3-S768I cell lines were less sensitive to erlotinib, compared with the Ba/F3-L858R cell line, but their sensitivities to afatinib were similar to that of the Ba/F3-L858R cell line. The Ba/F3-L861Q cell line was similarly sensitive and the Ba/F3-S768I cell line was less sensitive to osimertinib, compared with the Ba/F3-L858R cell line. The results of western blot analyses were consistent with these sensitivities. Next, similar experiments were also performed using the KYSE270 (L861Q) and KYSE 450 (S768I) cell lines, and their results were compatible with those of the transfectant Ba/F3 cell lines. Our findings suggest that NSCLC harboring the EGFR L861Q mutation might be sensitive to afatinib or osimertinib and that NSCLC harboring the EGFR S768I mutation might be sensitive to afatinib. Overall, afatinib might be the optimal EGFR-TKI against these uncommon EGFR mutations. PMID:27240419

  15. Different interleukin 2 receptor beta-chain tyrosines couple to at least two signaling pathways and synergistically mediate interleukin 2-induced proliferation.

    OpenAIRE

    Friedmann, M C; Migone, T S; Russell, S M; Leonard, W J

    1996-01-01

    One of the earliest events induced by interleukin 2 (IL-2) is tyrosine phosphorylation of cellular proteins, including the IL-2 receptor beta chain (IL-2Rbeta). Simultaneous mutation of three tyrosines (Y338, Y392, and Y510) in the IL-2Rbeta cytoplasmic domain abrogated IL-2-induced proliferation, whereas mutation of only Y338 or of Y392 and Y510 inhibited proliferation only partially. While Y392 and Y510 were critical for IL-2-induced activation of signal transducers and activators of transc...

  16. Coarse-grained molecular simulation of epidermal growth factor receptor protein tyrosine kinase multi-site self-phosphorylation.

    Directory of Open Access Journals (Sweden)

    John G Koland

    2014-01-01

    Full Text Available Upon the ligand-dependent dimerization of the epidermal growth factor receptor (EGFR, the intrinsic protein tyrosine kinase (PTK activity of one receptor monomer is activated, and the dimeric receptor undergoes self-phosphorylation at any of eight candidate phosphorylation sites (P-sites in either of the two C-terminal (CT domains. While the structures of the extracellular ligand binding and intracellular PTK domains are known, that of the ∼225-amino acid CT domain is not, presumably because it is disordered. Receptor phosphorylation on CT domain P-sites is critical in signaling because of the binding of specific signaling effector molecules to individual phosphorylated P-sites. To investigate how the combination of conventional substrate recognition and the unique topological factors involved in the CT domain self-phosphorylation reaction lead to selectivity in P-site phosphorylation, we performed coarse-grained molecular simulations of the P-site/catalytic site binding reactions that precede EGFR self-phosphorylation events. Our results indicate that self-phosphorylation of the dimeric EGFR, although generally believed to occur in trans, may well occur with a similar efficiency in cis, with the P-sites of both receptor monomers being phosphorylated to a similar extent. An exception was the case of the most kinase-proximal P-site-992, the catalytic site binding of which occurred exclusively in cis via an intramolecular reaction. We discovered that the in cis interaction of P-site-992 with the catalytic site was facilitated by a cleft between the N-terminal and C-terminal lobes of the PTK domain that allows the short CT domain sequence tethering P-site-992 to the PTK core to reach the catalytic site. Our work provides several new mechanistic insights into the EGFR self-phosphorylation reaction, and demonstrates the potential of coarse-grained molecular simulation approaches for investigating the complexities of self-phosphorylation in

  17. Met receptor tyrosine kinase signaling induces secretion of the angiogenic chemokine interleukin-8/CXCL8 in pancreatic cancer.

    Directory of Open Access Journals (Sweden)

    Kristen S Hill

    Full Text Available At diagnosis, the majority of pancreatic cancer patients present with advanced disease when curative resection is no longer feasible and current therapeutic treatments are largely ineffective. An improved understanding of molecular targets for effective intervention of pancreatic cancer is thus urgent. The Met receptor tyrosine kinase is one candidate implicated in pancreatic cancer. Notably, Met is over expressed in up to 80% of invasive pancreatic cancers but not in normal ductal cells correlating with poor overall patient survival and increased recurrence rates following surgical resection. However the functional role of Met signaling in pancreatic cancer remains poorly understood. Here we used RNA interference to directly examine the pathobiological importance of increased Met signaling for pancreatic cancer. We show that Met knockdown in pancreatic tumor cells results in decreased cell survival, cell invasion, and migration on collagen I in vitro. Using an orthotopic model for pancreatic cancer, we provide in vivo evidence that Met knockdown reduced tumor burden correlating with decreased cell survival and tumor angiogenesis, with minimal effect on cell growth. Notably, we report that Met signaling regulates the secretion of the pro-angiogenic chemokine interleukin-8/CXCL8. Our data showing that the interleukin-8 receptors CXCR1 and CXCR2 are not expressed on pancreatic tumor cells, suggests a paracrine mechanism by which Met signaling regulates interleukin-8 secretion to remodel the tumor microenvironment, a novel finding that could have important clinical implications for improving the effectiveness of treatments for pancreatic cancer.

  18. The insulin receptor with phenylalanine replacing tyrosine-1146 provides evidence for separate signals regulating cellular metabolism and growth

    International Nuclear Information System (INIS)

    The authors have studied the function of a mutant insulin receptor (IR) molecule in which Try-1146, one of the first autophosphorylation sites in the β subunit, was replaced with phenylalanine (IRF1146). Autophosphorylation of the partially purified IRF1146 was reduced 60-70% when compared to the wild-type IR but was still stimulated by insulin. The phosphotransferase activity of the dephospho form of both the IR and IRF1146 toward exogenous substrates was stimulated 3- to 4-fold by insulin. However, the wild-type IR was activated 12-fold by autophosphorylation, whereas the IRF1146 was activated only 2-fold. When the IRF1146 was expressed in Chinese hamster ovary (CHO) cells, [125I]-insulin binding was normal, whereas autophosphorylation was reduced 80% when compared to cells expressing the wild-type IR. Endogeneous substrates of the insulin receptor kinase were not detected during insulin stimulation of CHO cells expressing the IRF1146. These data suggest that activation of the IR tyrosine kinase can be resolved into two components: the first is dependent on insulin binding and the second is dependent on the subsequent insulin-stimulated autophosphorylation cascade. Thus, at least two signal transduction pathways diverging from the IR are implicated in the mechanism of insulin action

  19. 1,2-Naphthoquinone activates vanilloid receptor 1 through increased protein tyrosine phosphorylation, leading to contraction of guinea pig trachea

    International Nuclear Information System (INIS)

    1,2-Naphthoquinone (1,2-NQ) has recently been identified as an environmental quinone in diesel exhaust particles (DEP) and atmospheric PM2.5. We have found that this quinone is capable of causing a concentration-dependent contraction of tracheal smooth muscle in guinea pigs with EC5 value of 18.7 μM. The contraction required extracellular calcium and was suppressed by L-type calcium channel blockers nifedipine and diltiazem. It was found that 1,2-NQ activated phospholipase A2 (PLA2)/lipoxygenase (LO)/vanilloid receptor (VR1) signaling. Additionally, 1,2-NQ was capable of transactivating protein tyrosine kinases (PTKs) such as epidermal growth factor receptor (EGFR) in guinea pig trachea, suggesting that phosphorylation of PTKs contributes to 1,2-NQ-induced tracheal contraction. Consistent with this notion, this action was blocked by the PTKs inhibitor genistein and the EGFR antagonist PD153035, indicating that contraction was, at least in part, attributable to PTKs phosphorylation that activates VR1, resulting in increased intracellular calcium content in the smooth muscle cells

  20. The Role of Epidermal Growth Factor Receptor Mutations and Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors in the Treatment of Lung Cancer

    International Nuclear Information System (INIS)

    Lung cancer is the leading cause of cancer-related deaths worldwide. Non-small-cell lung cancer (NSCLC) cases comprise approximately 85% of the lung cancer cases. Before the era of target therapy, platinum-based doublet chemotherapy only led to a median survival of 8–9 months and a one-year survival of 30%–40% in patients with advanced NSCLC. In July 2002, gefitinib, a small-molecule epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), was approved for the treatment of patients with advanced NSCLC in Japan. After the widespread use of gefitinib in the treatment of NSCLC, there have been many new studies regarding the association between the clinical anticancer efficacy of gefitinib and the somatic EGFR mutation status in patients with NSCLC. This article summarizes the role of EGFR mutations in lung cancer and the use of EGFR antagonists in the treatment of lung cancer and its associated adverse effects

  1. Effect of ionizing radiation on receptor tyrosine kinases and p16 expression in human malignant melanoma cell lines

    International Nuclear Information System (INIS)

    Receptor tyrosine kinases (RTK) of subclass I are a group of cell surface receptors which upon binding of a ligand excert signal transduction processes. They are involved in the pathogenesis of different types of cancer, such as malignant melanoma or mammary carcinoma. p16, a cell cycle regulator has been shown to be a decisive tumor suppressor gene in human malignant melanoma. Since the effect of UV-radiation on melanoma cells has been demonstrated, a possible effect of ionizing radiation on the expression of RTK and p16 was studied in melanoma cell lines by Northern blot analysis and RT-PCR. The expression of the Epidermal Growth Factor Receptor, her2/neu and a human homologous exon of Xmrk, the causative oncogene in melanoma formation in the teleost fish Xiphophorus was studied in human malignant melanoma cell lines after exposure to 1 - 6 Gy of ionizing radiation (240 kV x-ray, FOD 40 cm, dose rate 1 Gy/min). It could be demonstrated that the expression levels of these RTK are upregulated after exposure to ionizing radiation, showing a maximum at 6 Gy for the Xmrk homologous exon and her2/neu whereas EGFR reached a maximum at 1 Gy. p16 expression is altered in a similar way by ionizing radiation. These data clearly indicate that oncogene and tumor suppressor gene expression are affected by ionizing radiation in melanoma cell lines, providing an explanation for the lack of radiosensitivity of many primary malignant melanomas and melanoma metastases. On the contrary, the upregulated RTK expression, e.g. the EGFR expression could be utilized for a targeted radiation-gene therapy

  2. Bombesin receptor subtype-3 agonists stimulate the growth of lung cancer cells and increase EGF receptor tyrosine phosphorylation

    OpenAIRE

    Moody, Terry W.; Sancho, Veronica; Florio, Alessia di; Nuche-Berenguer, Bernardo; Mantey, Samuel; Jensen, Robert T.

    2011-01-01

    The effects of bombesin receptor subtype-3 (BRS-3) agonists were investigated on lung cancer cells. The BRS-3 agonist (DTyr6, βAla11, Phe13, Nle14)bombesin6-14 (BA1), but not gastrin releasing peptide (GRP) or neuromedin B (NMB) increased significantly the clonal growth of NCI-H1299 cells stably transfected with BRS-3 (NCI-H1299-BRS-3). Also, BA1 addition to NCI-H727 or NCI-H1299-BRS-3 cells caused Tyr1068 phosphorylation of the epidermal growth factor receptor (EGFR). Similarly, (DTyr6, R-Ap...

  3. Cloning and characterization of R-PTP-kappa, a new member of the receptor protein tyrosine phosphatase family with a proteolytically cleaved cellular adhesion molecule-like extracellular region

    DEFF Research Database (Denmark)

    Jiang, Y P; Wang, H; D'Eustachio, P; Musacchio, J M; Schlessinger, J; Sap, J

    1993-01-01

    We describe a new member of the receptor protein tyrosine phosphatase family, R-PTP-kappa, cDNA cloning predicts that R-PTP-kappa is synthesized from a precursor protein of 1,457 amino acids. Its intracellular domain displays the classical tandemly repeated protein tyrosine phosphatase homology, ...

  4. Oncogenic tyrosine kinase NPM-ALK induces expression of the growth-promoting receptor ICOS

    DEFF Research Database (Denmark)

    Zhang, Qian; Wang, HongYi; Kantekure, Kanchan; Paterson, Jennifer C.; Liu, Xiaobin; Schaffer, Andreas; Paulos, Chrystal; Milone, Michael C.; Ødum, Niels; Turner, Suzanne; Marafioti, Teresa; Wasik, Mariusz A.

    2011-01-01

    protein. Stimulation of the ICOS receptor with anti-ICOS antibody or ICOS ligand-expressing B cells markedly enhanced proliferation of the ALK(+) TCL cells. These results demonstrate that NPM-ALK, acting through STAT3 as the gene transcriptional activator, induces the expression of ICOS, a cell growth......Here we report that T-cell lymphoma cells carrying the NPM-ALK fusion protein (ALK(+) TCL) frequently express the cell-stimulatory receptor ICOS. ICOS expression in ALK(+) TCL is moderate and strictly dependent on the expression and enzymatic activity of NPM-ALK. NPM-ALK induces ICOS expression via...... STAT3, which triggers the transcriptional activity of the ICOS gene promoter. In addition, STAT3 suppresses the expression of miR-219 that, in turn, selectively inhibits ICOS expression. ALK(+) TCL cell lines display extensive DNA methylation of the CpG island located within intron 1, the putative...

  5. Receptor protein tyrosine kinase EphB4 is up-regulated in colon cancer

    Directory of Open Access Journals (Sweden)

    Hewett Peter J

    2001-12-01

    Full Text Available Abstract Background We have used commercially available cDNA arrays to identify EphB4 as a gene that is up-regulated in colon cancer tissue when compared with matched normal tissue from the same patient. Results Quantitative RT-PCR analysis of the expression of the EphB4 gene has shown that its expression is increased in 82% of tumour samples when compared with the matched normal tissue from the same patient. Using immunohistochemistry and Western analysis techniques with an EphB4-specific antibody, we also show that this receptor is expressed in the epithelial cells of the tumour tissue and either not at all, or in only low levels, in the normal tissue. Conclusion The results presented here supports the emerging idea that Eph receptors play a role in tumour formation and suggests that further elucidation of this signalling pathway may identify useful targets for cancer treatment therapies.

  6. Biotinylated phosphoproteins from kinase-catalyzed biotinylation are stable to phosphatases: Implications for phosphoproteomics

    OpenAIRE

    Senevirathne, Chamara; Pflum, Mary Kay H.

    2013-01-01

    Kinase-catalyzed protein phosphorylation is involved in a wide variety of cellular events. Development of methods to monitor phosphorylation is critical to understand cell biology. Our lab recently discovered kinase-catalyzed biotinylation, where ATP-biotin is utilized by kinases to label phosphopeptides or phosphoproteins with a biotin tag. To exploit kinase-catalyzed biotinylation for phosphoprotein purification and identification in a cellular context, the susceptibility of the biotin tag ...

  7. Inhibition of tyrosine kinase receptors by SU6668 promotes abnormal stromal development at the periphery of carcinomas

    Science.gov (United States)

    Farace, P; Galiè, M; Merigo, F; Daducci, A; Calderan, L; Nicolato, E; Degrassi, A; Pesenti, E; Sbarbati, A; Marzola, P

    2009-01-01

    Dynamic contrast-enhanced (albumin-Gd-DTPA) magnetic resonance imaging, performed during 2 weeks of daily administration of an inhibitor of tyrosine kinase receptors (SU6668) in an HT-29 colon carcinoma model, revealed the onset of a hyper-enhancing rim, not observed in untreated tumours. To account for tissue heterogeneity in the quantitative analysis, we segmented tumours into three subunits automatically identified by cluster analysis of the enhancement curves using a k-means algorithm. Transendothelial permeability (Kps) and fractional plasma volume (fPV) were calculated in each subunit. An avascular and necrotic region, an intermediate zone and a well-vascularised periphery were reliably identified. During untreated tumour growth, the identified sub-regions did not substantially change their enhancement pattern. Treatment with SU6668 induced major changes at tumour periphery where a significant increase of Kps and fPV was observed with respect to control tumours. Histology revealed a sub-capsular layer composed of hyper-dense viable tumour cells in the periphery of untreated tumours. The rim of viable neoplastic cells was reduced in treated tumours, and replaced by loose connective tissue characterised by numerous vessels, which explains the observed hyper-enhancement. The present data show a peripheral abnormal development of cancer-associated stroma, indicative of an adaptive response to anti-angiogenic treatment. PMID:19384298

  8. Study of Mutation in Tyrosine Protein Kinase of Insulin Receptor Gene in Patients with Polycystic Ovarian Syndrome

    Institute of Scientific and Technical Information of China (English)

    Min LI; Hong-yu QIU; Yong-yu SUN; Hong-fa LI; Yong-li CHU

    2003-01-01

    Objective To explore the molecular mechanism of insulin resistance in the patients with polycystic ovarian syndrome (PCOS)Methods Polymerase chain reaction, silver staining-single strand conformation polymorphism(PCR-SSCP) and DNA direct sequencing were used to detect the mutation of insulin receptor(INSR) gene in exon 17~21 with the abdominal wall adipose tissue from 31 patients with PCOS (PCOS Group) and 30 patients with pure hysteromyoma in reproductive lift (Control Group).Results Twenty-two variant SSCP patterns in exon 17 of INSR gene were detected. Direct sequence analysis of exon 17 showed that homozygous nonsense mutation was two alleles single nucleotide polymorphism(SNP) at the codon 1058 (CAC→CAT). Exons 18~21 were not detected with any significantly mutation. The INSR gene His1058C→T substitution collecting rate and insulin resistance were significantly higher in the PCOS group than in the control group (P=0.0293, P<0.05, P<0.01).Conclusion It is suggested that the SNP in codon 1058 of the INSR gene might be related with the insulin resistance in PCOS patients, which has hereditary tendency. And the missense mutation,nonsense mutation and frameshift mutation at exons 18~21 in tyrosine protein kinase region of INSR gene for PCOS patients were not frequently observed.

  9. Nucleotide sequence variation within the human tyrosine kinase B neurotrophin receptor gene: association with antisocial alcohol dependence.

    Science.gov (United States)

    Xu, K; Anderson, T R; Neyer, K M; Lamparella, N; Jenkins, G; Zhou, Z; Yuan, Q; Virkkunen, M; Lipsky, R H

    2007-12-01

    To identify sequence variants in genes that may have roles in neuronal responses to alcohol, we resequenced the 5' region of tyrosine kinase B neurotrophin receptor gene (NTRK2) and determined linkage disequilibrium (LD) values, haplotype structure, and performed association analyses using 43 single nucleotide polymorphisms (SNPs) covering the entire NTRK2 region in a Finnish Caucasian sample of 229 alcohol-dependent subjects with antisocial personality disorder (ASPD) and 287 healthy controls. Individually, three SNPs were associated with alcohol dependence and alcohol abuse (AD) (P-value from 0.0019 to 0.0059, significance level was set at P

  10. Management of hyperglycemia from epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) targeting T790M-mediated resistance.

    Science.gov (United States)

    Villadolid, Jeryl; Ersek, Jennifer L; Fong, Mei Ka; Sirianno, Lindsey; Story, Ellen S

    2015-10-01

    Epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) patients are associated with sensitivity to small molecule tyrosine kinase inhibitors (TKIs) such as erlotinib, gefitinib, and afatinib. Although studies show an increased progression free survival (PFS) with use of EGFR TKIs in the first-line setting, most patients will develop resistance to therapy after the first 8-16 months. T790M is an acquired resistance mutation reported in 60-70% of patients who initially responded to a prior EGFR TKI. Recently, EGFR TKIs targeting T790M have been developed to overcome resistance with positive results in PFS and objective response rate in patients who have had disease progression on at least one TKI. Two EGFR TKIs targeting T790M, AZD9291 and rociletinib, are new active treatment options for NSCLC but differ in adverse effect profiles. Dose-limiting hyperglycemia has been reported with rociletinib and has required dose reduction, an oral antihyperglycemic, or both, without discontinuation of therapy. This suggests that patients may be effectively treated chronically for hyperglycemia associated with EGFR TKIs targeting T790M, however, guidelines for treatment of hyperglycemia in this setting have not been published. We discuss mechanisms of hyperglycemia associated with TKIs and initial management of hyperglycemia, including benefits and limitations of oral antihyperglycemic options, adjustment of therapy based on grade of hyperglycemia, and recommendations for follow-up glucose monitoring. PMID:26629426

  11. Multiple myeloma is affected by multiple and heterogeneous somatic mutations in adhesion- and receptor tyrosine kinase signaling molecules

    International Nuclear Information System (INIS)

    Multiple myeloma (MM) is a largely incurable plasma cell malignancy with a poorly understood and heterogeneous clinical course. To identify potential, functionally relevant somatic mutations in MM, we performed whole-exome sequencing of five primary MM, corresponding germline DNA and six MM cell lines, and developed a bioinformatics strategy that also integrated published mutational data of 38 MM patients. Our analysis confirms that identical, recurrent mutations of single genes are infrequent in MM, but highlights that mutations cluster in important cellular pathways. Specifically, we show enrichment of mutations in adhesion molecules of MM cells, emphasizing the important role for the interaction of the MM cells with their microenvironment. We describe an increased rate of mutations in receptor tyrosine kinases (RTKs) and associated signaling effectors, for example, in EGFR, ERBB3, KRAS and MAP2K2, pointing to a role of aberrant RTK signaling in the development or progression of MM. The diversity of mutations affecting different nodes of a particular signaling network appears to be an intrinsic feature of individual MM samples, and the elucidation of intra- as well as interindividual redundancy in mutations that affect survival pathways will help to better tailor targeted therapeutic strategies to the specific needs of the MM patient

  12. Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors for Elderly Patients with Advanced Non-Small Cell Lung Cancer

    Directory of Open Access Journals (Sweden)

    A. Zaniboni

    2010-01-01

    Full Text Available Lung cancer is the leading cause of cancer-related mortality in both men and women and approximately 219,440 new cases of nonsmall cell lung cancer (NSCLC were estimated to occur in the USA in 2009, which caused 159,390 NSCLC-related deaths. More than 50% of cases of advanced NSCLC are diagnosed in patients older than age 65, and recent Surveillance Epidemiology and End Results (SEERs data suggest that the median age at diagnosis is 70 years. Until recently, the disease has been undertreated in this patient population, with a perception among many clinicians that elderly patients do not tolerate chemotherapy or radiotherapy. So, single agent chemotherapy is the recommended approach by the ASCO and International Expert Panels in unselected patients. The introduction of novel targeted therapies, such as Epidermal Growth Factor Receptor (EGFR Tyrosine Kinase Inhibitors (TKIs which improved survival versus placebo in patients who had previously failed on chemotherapy, gives clinicians new, effective, and better tolerated options to consider when treating NSCLC in elderly patients. This paper describes the advances of EGFR TKIs for elderly patients with advanced NSCLC.

  13. Decreased expression of protein tyrosine phosphatase non-receptor type 12 is involved in the proliferation and recurrence of bladder transitional cell carcinoma

    OpenAIRE

    PIAO, YONGRUI; LIU, XIANKUI; Lin, Zhenhua; Jin, Zhehu; JIN, XUANSHUN; Yuan, Kuichang; Wu, Wenyuan

    2015-01-01

    Protein tyrosine phosphatase non-receptor type 12 (PTPN12) has been shown to be involved in the development of a number of types of carcinoma. However, the effect of PTPN12 on the proliferation and recurrence of human bladder transitional cell carcinoma (TCC) is unclear. The present study aimed to investigate the expression and function of PTPN12 in human TCC. Samples from 164 patients with TCC, in addition to 146 patients undergoing bladder surgery for indications other than TCC, were examin...

  14. The Molecular Balance between Receptor Tyrosine Kinases Tie1 and Tie2 Is Dynamically Controlled by VEGF and TNFα and Regulates Angiopoietin Signalling

    OpenAIRE

    Harprit Singh; Hansen, Tania M.; Nisha Patel; Nicholas P J Brindle

    2012-01-01

    Angiopoietin-1 (Ang1) signals via the receptor tyrosine kinase Tie2 which exists in complex with the related protein Tie1 at the endothelial cell surface. Tie1 undergoes regulated ectodomain cleavage in response to phorbol esters, vascular endothelial growth factor (VEGF) and tumour necrosis factor-α (TNFα). Recently phorbol esters and VEGF were found also to stimulate ectodomain cleavage of Tie2. Here we investigate for the first time the effects of factors activating ectodomain cleavage on ...

  15. Phospholipase C-gamma, a substrate for PDGF receptor kinase, is not phosphorylated on tyrosine during the mitogenic response to CSF-1.

    OpenAIRE

    Downing, J R; Margolis, B L; Zilberstein, A; Ashmun, R A; Ullrich, A; Sherr, C J; Schlessinger, J

    1989-01-01

    Quiescent mouse NIH3T3 cells expressing a transduced human c-fms gene encoding the receptor for colony stimulating factor-1 (CSF-1) were stimulated with mitogenic concentrations of platelet-derived growth factor (PDGF) or CSF-1. Immunoprecipitated phospholipase C-gamma (PLC-gamma) was phosphorylated on tyrosine and calcium was mobilized following treatment of intact cells with PDGF. In contrast, only trace amounts of phosphotyrosine were incorporated into PLC-gamma and no intracellular calciu...

  16. Expression profiling of receptor tyrosine kinases in high-grade neuroendocrine carcinoma of the lung: a comparative analysis with adenocarcinoma and squamous cell carcinoma

    OpenAIRE

    MATSUMURA, YUKI; Umemura, Shigeki; Ishii, Genichiro; Tsuta, Koji; Matsumoto, Shingo; Aokage, Keiju; Hishida, Tomoyuki; Yoshida, Junji; Ohe, Yuichiro; Suzuki, Hiroyuki; Ochiai, Atsushi; Goto, Koichi; Nagai, Kanji; Tsuchihara, Katsuya

    2015-01-01

    Background As the comprehensive genomic analysis of small cell lung cancer (SCLC) progresses, novel treatments for this disease need to be explored. With attention to the direct connection between the receptor tyrosine kinases (RTKs) of tumor cells and the pharmacological effects of specific inhibitors, we systematically assessed the RTK expressions of high-grade neuroendocrine carcinomas of the lung [HGNECs, including SCLC and large cell neuroendocrine carcinoma (LCNEC)]. Patients and method...

  17. Nomogram Predicting Clinical Outcomes in Non-small Cell Lung Cancer Patients Treated with Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors

    OpenAIRE

    Keam, Bhumsuk; Kim, Dong-Wan; Park, Jin Hyun; Lee, Jeong-Ok; Kim, Tae Min; Lee, Se-Hoon; Chung, Doo Hyun; Heo, Dae Seog

    2014-01-01

    Purpose The aim of this study was to develop a pragmatic nomogram for prediction of progressionfree survival (PFS) for the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) in EGFR mutant non-small cell lung cancer (NSCLC). Materials and Methods A total of 306 recurred or metastatic NSCLC patients with EGFR mutation, who received EGFR TKIs, were enrolled in this study. We developed the nomogram, using a Cox proportional hazard regression model for PFS. Results The median...

  18. EphA4 receptor tyrosine kinase is a modulator of onset and disease severity of experimental autoimmune encephalomyelitis (EAE.

    Directory of Open Access Journals (Sweden)

    Kathryn M Munro

    Full Text Available The EphA4 receptor tyrosine kinase is a major regulator of axonal growth and astrocyte reactivity and is a possible inflammatory mediator. Given that multiple sclerosis (MS is primarily an inflammatory demyelinating disease and in mouse models of MS, such as experimental autoimmune encephalomyelitis (EAE, axonal degeneration and reactive gliosis are prominent clinical features, we hypothesised that endogenous EphA4 could play a role in modulating EAE. EAE was induced in EphA4 knockout and wildtype mice using MOG peptide immunisation and clinical severity and histological features of the disease were then compared in lumbar spinal cord sections. EphA4 knockout mice exhibited a markedly less severe clinical course than wildtype mice, with a lower maximum disease grade and a slightly later onset of clinical symptoms. Numbers of infiltrating T cells and macrophages, the number and size of the lesions, and the extent of astrocytic gliosis were similar in both genotypes; however, EphA4 knockout mice appeared to have decreased axonal pathology. Blocking of EphA4 in wildtype mice by administration of soluble EphA4 (EphA4-Fc as a decoy receptor following induction of EAE produced a delay in onset of clinical symptoms; however, most mice had clinical symptoms of similar severity by 22 days, indicating that EphA4 blocking treatment slowed early EAE disease evolution. Again there were no apparent differences in histopathology. To determine whether the role of EphA4 in modulating EAE was CNS mediated or due to an altered immune response, MOG primed T cells from wildtype and EphA4 knockout mice were passively transferred into naive recipient mice and both were shown to induce disease of equivalent severity. These results are consistent with a non-inflammatory, CNS specific, deleterious effect of EphA4 during neuroinflammation that results in axonal pathology.

  19. Receptor tyrosine kinase inhibition causes simultaneous bone loss and excess bone formation within growing bone in rats

    International Nuclear Information System (INIS)

    During postnatal skeletal growth, adaptation to mechanical loading leads to cellular activities at the growth plate. It has recently become evident that bone forming and bone resorbing cells are affected by the receptor tyrosine kinase (RTK) inhibitor imatinib mesylate (STI571, Gleevec (registered) ). Imatinib targets PDGF, ABL-related gene, c-Abl, c-Kit and c-Fms receptors, many of which have multiple functions in the bone microenvironment. We therefore studied the effects of imatinib in growing bone. Young rats were exposed to imatinib (150 mg/kg on postnatal days 5-7, or 100 mg/kg on postnatal days 5-13), and the effects of RTK inhibition on bone physiology were studied after 8 and 70 days (3-day treatment), or after 14 days (9-day treatment). X-ray imaging, computer tomography, histomorphometry, RNA analysis and immunohistochemistry were used to evaluate bone modeling and remodeling in vivo. Imatinib treatment eliminated osteoclasts from the metaphyseal osteochondral junction at 8 and 14 days. This led to a resorption arrest at the growth plate, but also increased bone apposition by osteoblasts, thus resulting in local osteopetrosis at the osteochondral junction. The impaired bone remodelation observed on day 8 remained significant until adulthood. Within the same bone, increased osteoclast activity, leading to bone loss, was observed at distal bone trabeculae on days 8 and 14. Peripheral quantitative computer tomography (pQCT) and micro-CT analysis confirmed that, at the osteochondral junction, imatinib shifted the balance from bone resorption towards bone formation, thereby altering bone modeling. At distal trabecular bone, in turn, the balance was turned towards bone resorption, leading to bone loss. - Research highlights: → 3-Day imatinib treatment. → Causes growth plate anomalies in young rats. → Causes biomechanical changes and significant bone loss at distal trabecular bone. → Results in loss of osteoclasts at osteochondral junction.

  20. Tyrosine kinase of insulin-like growth factor receptor as target for novel treatment and prevention strategies of colorectal cancer

    Institute of Scientific and Technical Information of China (English)

    Michael H(o)pfner; Andreas P Sutter; Alexander Huether; Viola Baradari; Hans Scherübl

    2006-01-01

    AIM: To investigate the antineoplastic potency of the novel insulin-like growth factor 1 receptor (IGF-1R) tyrosine kinase inhibitor (TKI) NVP-AEW541 in cell lines and primary cell cultures of human colorectal cancer (CRC).METHODS: Cells of primary colorectal carcinomas were from 8 patients. Immunostaining and crystal violet staining were used for analysis of growth factor receptor protein expression and detection of cell number changes,respectively. Cytotoxicity was determined by measuring the release of the cytoplasmic enzyme lactate dehydrogenase (LDH). The proportion of apoptotic cells was determined by quantifying the percentage of sub-G1(hypodiploid) cells. Cell cycle status reflected by the DNA content of the nuclei was detected by flow cytometry.RESULTS: NVP-AEW541 dose-dependently inhibited the proliferation of colorectal carcinoma cell lines and primary cell cultures by inducing apoptosis and cell cycle arrest. Apoptosis was characterized by caspase-3 activation and nuclear degradation. Cell cycle was arrested at the G1/S checkpoint. The NVP-AEW541-mediated cell cycle-related signaling involved the inactivation of Akt and extracellular signal-regulated kinase (ERK) 1/2, the upregulation of the cyclin-dependent kinase inhibitors p21Waf1/CIP1 and p27Kip1, and the downregulation of the cell cycle promoter cyclin D1. Moreover, BAX was upregulated during NVP-AEW541-induced apoptosis, whereas Bcl-2 was downregulated. Measurement of LDH release showed that the antineoplastic effect of NVP-AEW541 was not due to general cytotoxicity of the compound.However, augmented antineoplastic effects were observed in combination treatments of NVP-AEW541 with either 5-FU, or the EGFR-antibody cetuximab, or the HMG-CoA-reductase inhibitor fluvastatin.CONCLUSION: IGF-1R-TK inhibition is a promising novel approach for either mono- or combination treatment strategies of colorectal carcinoma and even for CRC chemoprevention.

  1. Glycoxidised LDL induced the upregulation of Axl receptor tyrosine kinase and its ligand in mouse mesangial cells.

    Directory of Open Access Journals (Sweden)

    Young Sook Kim

    Full Text Available AIM/HYPOTHESIS: Low-density lipoprotein (LDL is subjected to glycoxidation in diabetes, and a novel signalling mechanism by which glycoxidised LDL functions in glomerular mesangial cells remains to be ascertained. METHODS: We performed gene expression analysis in mouse glomerular mesangial cells treated with LDL modified by glycation and oxidation (GO-LDL, 100 µg/ml for 48 h by using DNA microarray analysis and quantitative real-time PCR. We examined the GO-LDL-specific changes in gene and protein expression in mesangial cells and glomeruli of type 2 diabetic Zucker diabetic fatty (ZDF rats. RESULTS: By microarray profiling, we noted that GO-LDL treatment increased Axl receptor tyrosine kinase (Axl mRNA expression (∼2.5-fold, p<0.05 compared with normal LDL (N-LDL treatment in mesangial cells. Treatment with GO-LDL also increased the protein levels of Axl and its ligand Gas6 as measured by Western blotting. These increases were inhibited by neutralising Axl receptor-specific antibody. Silencing Gas6 by siRNA inhibited GO-LDL-induced Axl expression in mesangial cells. Axl and Gas6 protein were also increased in cells cultured in high glucose (30 mM or methylglyoxal (200 µM. Gas6 treatment increased the expression and secretion of TGF-β1 protein, a key regulator of extracellular matrix expression in the glomeruli of diabetic kidneys. Immunohistochemical analyses of glomeruli from 20-week-old ZDF rats exhibited increased Axl protein expression. Rottlerin, a selective PKC-δ inhibitor, completely blocked Gas6-induced TGF-β1 expression. CONCLUSIONS/INTERPRETATION: These data suggest that LDL modified by glycoxidation may mediate Axl/Gas6 pathway activation, and this mechanism may play a significant role in the pathogenesis of diabetic nephropathy.

  2. Effect of ghrelin receptor agonist and antagonist on the activity of arcuate nucleus tyrosine hydroxylase containing neurons in C57BL/6 male mice exposed to normal or high fat diet

    Czech Academy of Sciences Publication Activity Database

    Pirník, Z.; Majerčíková, Z.; Holubová, Martina; Pirník, R.; Železná, Blanka; Maletínská, Lenka; Kiss, A.

    2014-01-01

    Roč. 65, č. 4 (2014), s. 477-486. ISSN 0867-5910 Institutional support: RVO:61388963 Keywords : growth hormone secretagogue receptor * ghrelin receptor agonist * ghrelin receptor antagonist * high fat diet * tyrosine hydroxylase * arcuate nucleus * food intake Subject RIV: CE - Biochemistry Impact factor: 2.386, year: 2014

  3. Muscle-Specific Receptor Tyrosine Kinase (MuSK) Myasthenia Gravis.

    Science.gov (United States)

    Hurst, Rebecca L; Gooch, Clifton L

    2016-07-01

    Autoimmune myasthenia gravis (MG) is the prototypic, antibody-mediated neuromuscular disease and is characterized by a decrease in the number of functional acetylcholine receptors (AChR) within the muscle end plate zone of the neuromuscular junction (NMJ). Although the pathophysiology of AChR-mediated myasthenia gravis has been extensively studied over the last 40 years since its original description by Patrick and Lindstrom (Science 180:871-872, 1973), less is known about the much more recently described muscle-specific kinase (MuSK) antibody-mediated MG. MuSK-MG has features clinically distinct from Ach-R MG, as well as a different pattern of response to treatment and a unique immunopathogenesis. PMID:27170368

  4. Receptor protein tyrosine phosphatase alpha is essential for hippocampal neuronal migration and long-term potentiation

    DEFF Research Database (Denmark)

    Petrone, Angiola; Battaglia, Fortunato; Wang, Cheng;

    2003-01-01

    (RPTPalpha) regulates SRC family kinases, potassium channels and NMDA receptors. Here, we report that absence of RPTPalpha compromises correct positioning of pyramidal neurons during development of mouse hippocampus. Thus, RPTPalpha is a novel member of the functional class of genes that control radial...... neuronal migration. The migratory abnormality likely results from a radial glial dysfunction rather than from a neuron-autonomous defect. In spite of this aberrant development, basic synaptic transmission from the Schaffer collateral pathway to CA1 pyramidal neurons remains intact in Ptpra(-/-) mice....... However, these synapses are unable to undergo long-term potentiation. Mice lacking RPTPalpha also underperform in the radial-arm water-maze test. These studies identify RPTPalpha as a key mediator of neuronal migration and synaptic plasticity....

  5. Endothelial tyrosine kinase receptor B prevents VE-cadherin cleavage and protects against atherosclerotic lesion development in ApoE−/− mice

    OpenAIRE

    Jiang, Hong; Huang, Shuhong; Li, Xinyun; Li, Xian; Huang, ShanYing; Zhang, Yun; Chen, Zhe-Yu

    2015-01-01

    Tyrosine kinase receptor B (TrkB) is a high-affinity receptor for brain-derived neurotrophic factor (BDNF). In addition to its nervous system functions, TrkB is also expressed in the aortic endothelium. However, the effects of endothelial TrkB signaling on atherosclerosis remained unknown. Immunofluorescence analysis revealed that TrkB expression is downregulated in the endothelium of atherosclerotic lesions from ApoE−/− mice compared with the atheroma-free aorta of WT mice. Endothelial TrkB ...

  6. Tyrosine kinase inhibitors for epidermal growth factor receptor gene mutation-positive non-small cell lung cancers: an update for recent advances in therapeutics.

    Science.gov (United States)

    Chung, Clement

    2016-06-01

    The presence of activating gene mutations in the epidermal growth factor receptor of non-small cell lung cancer patients is predictive (improved progression-free survival and improved response rate) when treated with small molecule tyrosine kinase inhibitors such as gefitinib, erlotinib and afatinib. The two most common mutations that account for greater than 85% of all EGFR gene mutations are in-frame deletions in exon 19 (LREA deletions) and substitution in exon 21 (L858R). Exon 18 mutations occur much less frequently at about 4% of all EGFR gene mutations. Together, exon 19 deletion and exon 21 L858R gene substitution are present in about 10% of Caucasian patients and 20-40% of Asian patients with non-small cell lung cancer. T790M gene mutation at exon 20 is associated with acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors. Early studies showed that activating EGFR gene mutations are most common in patients with adenocarcinoma histology, women, never smokers and those of Asian ethnicity. A recent multi-center phase III trial suggested that frontline epidermal growth factor receptor tyrosine kinase inhibitor therapy with afatinib is associated with improved progression-free survival compared to chemotherapy regardless of race. Moreover, guidelines now suggest EGFR gene mutation testing should be conducted in all patients with lung adenocarcinoma or mixed lung cancers with an adenocarcinoma component, regardless of characteristics such as smoking status, gender or race. The success of targeted therapies in non-small cell lung cancer patients has changed the treatment paradigm in metastatic non-small cell lung cancer. However, despite a durable response of greater than a year, resistance to epidermal growth factor receptor tyrosine kinase inhibitors inevitably occurs. This mini-review describes the clinically relevant EGFR gene mutations and the efficacy/toxicity of small molecule epidermal growth factor receptor tyrosine kinase

  7. c-MET receptor tyrosine kinase as a molecular target in advanced hepatocellular carcinoma

    Directory of Open Access Journals (Sweden)

    Granito A

    2015-04-01

    Full Text Available Alessandro Granito,1 Elena Guidetti,1 Laura Gramantieri2,3 1Dipartimento di Scienze Mediche e Chirurgiche Università di Bologna, Bologna, Italy; 2Dipartimento dell'Apparato Digerente, Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy; 3Centro di Ricerca Biomedica Applicata (CRBA, Azienda Ospedaliero-Universitaria Policlinico S Orsola-Malpighi e Università di Bologna, Bologna, Italy Abstract: c-MET is the membrane receptor for hepatocyte growth factor (HGF, also known as scatter factor or tumor cytotoxic factor, a mitogenic growth factor for hepatocytes. HGF is mainly produced by cells of mesenchymal origin and it mainly acts on neighboring epidermal and endothelial cells, regulating epithelial growth and morphogenesis. HGF/MET signaling has been identified among the drivers of tumorigenesis in human cancers. As such, c-MET is a recognized druggable target, and against it, targeted agents are currently under clinical investigation. c-MET overexpression is a common event in a wide range of human malignancies, including gastric, lung, breast, ovary, colon, kidney, thyroid, and liver carcinomas. Despite c-MET overexpression being reported by a large majority of studies, no evidence for a c-MET oncogenic addiction exists in hepatocellular carcinoma (HCC. In particular, c-MET amplification is a rare event, accounting for 4%–5% of cases while no mutation has been identified in c-MET oncogene in HCC. Thus, the selection of patient subgroups more likely to benefit from c-MET inhibition is challenging. Notwithstanding, c-MET overexpression was reported to be associated with increased metastatic potential and poor prognosis in patients with HCC, providing a rationale for its therapeutic inhibition. Here we summarize the role of activated HGF/MET signaling in HCC, its prognostic relevance, and the implications for therapeutic approaches in HCC. Keywords: hepatocellular carcinoma, c-MET, clinical trials

  8. Decreased expression of neurotrophic tyrosine receptor kinase 3 is associated with the outflow tract defect of human tetralogy of Fallot

    Institute of Scientific and Technical Information of China (English)

    KONG Bo; LIU Ying-long; L(U) Xiao-dong

    2009-01-01

    Background The molecular mechanism of human tetralogy of Fallot (TOF) is incompletely defined. Animal models have suggested that neurotrophic tyrosine receptor kinase 3 (NTRK3) might be associated with the outflow tract defect, similar to that seen in human TOF, however, the expression pattern of NTRK3 in human TOF heart tissues has never been investigated. Methods Quantitative real-time PCR (qRT-PCR) and immunohistochemistry were applied to detect NTRK3 mRNA and protein levels in right ventricular outflow tract tissue samples of TOF patients, ventricular septal defect (VSD) patients and normal control infants (n=10 in each group). Results qRT-PCR analysis indicated that NTRK3 mRNA levels were significantly decreased in the TOF group compared to the VSD group (0.024±0.003 vs 0.085±0.004, P=0.022) and the normal control group (0.024±0.003 vs 0.091±0.002, P=0.006). Quantitative immunohistochemical analysis showed that NTRK3 protein was mainly localized in the myocardium cytoplasm in all 3 groups. The immunoreactivity of NTRK3 protein was again significantly lower in the TOF group compared to the VSD group (1.42±0.62 vs 14.12±1.83, P=0.023) and the control group (1.42±0.62 VS 16.25±2.31, P=0.008). The expression of NTRK3 in the VSD group and in the control group showed no significant differences at both mRNA and protein levels. Conclusions Insufficient expression of NTRK3 is associated with the outflow tract defect of human tetralogy of Fallot and may contribute to the progression of this defect.

  9. Tyrosine phosphatase Shp2 mediates the estrogen biological action in breast cancer via interaction with the estrogen extranuclear receptor.

    Directory of Open Access Journals (Sweden)

    Jun Li

    Full Text Available The extranuclear estrogen receptor pathway opens up novel perspectives in many physiological and pathological processes, especially in breast carcinogenesis. However, its function and mechanisms are not fully understood. Herein we present data identifying Shp2, a SH2-containing tyrosine phosphatase, as a critical component of extranuclear ER pathway in breast cancer. The research checked that the effect of Shp2 on the tumor formation and growth in animal model and investigated the regulation of Shp2 on the bio-effect and signaling transduction of estrogen in breast cancer cell lines. The results showed that Shp2 was highly expressed in more than 60% of total 151 breast cancer cases. The inhibition of Shp2 activity by PHPS1 (a Shp2 inhibitor delayed the development of dimethylbenz(aanthracene (DMBA-induced tumors in the rat mammary gland and also blocked tumor formation in MMTV-pyvt transgenic mice. Estradiol (E2 stimulated protein expression and phosphorylation of Shp2, and induced Shp2 binding to ERα and IGF-1R around the membrane to facilitate the phosphorylation of Erk and Akt in breast cancer cells MCF7. Shp2 was also involved in several biological effects of the extranuclear ER-initiated pathway in breast cancer cells. Specific inhibitors (phps1, phps4 and NSC87877 or small interference RNAs (siRNA of Shp2 remarkably suppressed E2-induced gene transcription (Cyclin D1 and trefoil factor 1 (TFF1, rapid DNA synthesis and late effects on cell growth. These results introduced a new mechanism for Shp2 oncogenic action and shed new light on extranuclear ER-initiated action in breast tumorigenesis by identifying a novel associated protein, Shp2, for extranuclear ER pathway, which might benefit the therapy of breast cancer.

  10. Radiosensitization of human breast cancer cells by a novel ErbB family receptor tyrosine kinase inhibitor

    International Nuclear Information System (INIS)

    Purpose: Overexpression of the ErbB family of growth factor receptors is present in a wide variety of human tumors and is correlated with poor prognosis. The purpose of this study was to determine the effects of a novel small molecule ErbB tyrosine kinase inhibitor, CI-1033, in combination with ionizing radiation on breast cancer cell growth and survival. Materials and Methods: Growth assays were performed on ErbB-overexpressing human breast cancer cells developed in our laboratory in the presence of 0.1-1.0 μM CI-1033 (Parke Davis). Clonogenic survival assays were performed in the presence of ionizing radiation with or without CI-1033. For some experiments, clonogen numbers, defined as the product of surviving fraction and total number of cells, were calculated at each time point during a course of multifraction radiation. Results: CI-1033 potently inhibited the growth of ErbB-overexpressing breast cancer cells. A single 48-h exposure of 1 μM CI-1033 resulted in growth inhibition for 7 days, whereas three times weekly administration resulted in sustained growth inhibition. Clonogenic survival was modestly decreased after a 7-day exposure to CI-1033. Exposure to both CI-1033 and radiation (6 Gy) yielded a 23-fold decrease in clonogenic survival compared to radiation alone. In a multifraction experiment, exposure to CI-1033 and three 5-Gy fractions of gamma radiation decreased the total number of clonogens in the population by 65-fold compared to radiation alone. Conclusion: CI-1033 results in potent growth inhibition and modest cytotoxicity of ErbB-overexpressing breast cancer cells, and has synergistic effects when combined with ionizing radiation. These data suggest that CI-1033 may have excellent clinical potential both alone and in combination with radiation therapy.

  11. The Mertk receptor tyrosine kinase promotes T-B interaction stimulated by IgD B-cell receptor cross-linking.

    Science.gov (United States)

    Shao, Wen-Hai; Zhen, Yuxuan; Finkelman, Fred D; Cohen, Philip L

    2014-09-01

    The Mertk receptor tyrosine kinase facilitates macrophage and DC apoptotic-cell clearance and regulates immune tolerance. Mertk may also contribute to B-cell activation, because Mertk-KO mice fail to develop autoantibodies when allo-activated by T cells. We investigated this possibility with a well-characterized model in which injection of mice with goat anti-IgD antibody causes membrane IgD cross-linking that induces T-independent B cell activation and antigen presentation to T cells. Goat anti-mouse IgD antibody-injected C57BL/6 Mertk-KO mice had normal initial B cell activation and proliferation, but significantly lower T cell activation and proliferation, as well as lower IgE and IgG anti-goat IgG responses, as compared to C57BL/6 WT controls. B cell antigen processing, analyzed by evaluating B cell fluorescence following injection of monoclonal anti-IgD antibody labeled with biotin or FITC, was comparable between Mertk-KO mice and WT mice. IgD Ab primed B cells from Mertk-KO mice exhibited significantly lower ability in activating memory T cells isolated from WT mice injected with the same antigen 10 days before. These observations suggest that Mertk expression is required for optimal B-cell antigen presentation, which is, in turn, required in this model for optimal T cell activation and subsequent T cell-dependent B cell differentiation. PMID:24768065

  12. Tyrosine phosphorylation of estradiol receptor by Src regulates its hormone-dependent nuclear export and cell cycle progression in breast cancer cells.

    Science.gov (United States)

    Castoria, G; Giovannelli, P; Lombardi, M; De Rosa, C; Giraldi, T; de Falco, A; Barone, M V; Abbondanza, C; Migliaccio, A; Auricchio, F

    2012-11-15

    We report that in breast cancer cells, tyrosine phosphorylation of the estradiol receptor alpha (ERalpha) by Src regulates cytoplasmic localization of the receptor and DNA synthesis. Inhibition of Src or use of a peptide mimicking the ERalpha p-Tyr537 sequence abolishes ERalpha tyrosine phosphorylation and traps the receptor in nuclei of estradiol-treated MCF-7 cells. An ERalpha mutant carrying a mutation of Tyr537 to phenylalanine (ER537F) persistently localizes in nuclei of various cell types. In contrast with ERalpha wt, ER537F does not associate with Ran and its interaction with Crm1 is insensitive to estradiol. Thus, independently of estradiol, ER537F is retained in nuclei, where it entangles FKHR-driving cell cycle arrest. Chromatin immunoprecipitation analysis reveals that overexpression of ER537F in breast cancer cells enhances FKHR interaction with cyclin D1 promoter. This mutant also counteracts cell transformation by the activated forms of Src or PI3-K. In conclusion, in addition to regulating receptor localization, ERalpha phosphorylation by Src is required for hormone responsiveness of DNA synthesis in breast cancer cells. PMID:22266855

  13. Plasma adiponectin concentration is associated with skeletal muscle insulin receptor tyrosine phosphorylation, and low plasma concentration precedes a decrease in whole-body insulin sensitivity in humans

    DEFF Research Database (Denmark)

    Stefan, Norbert; Vozarova, Barbora; Funahashi, Tohru;

    2002-01-01

    -induced tyrosine phosphorylation of the insulin receptor (IR) and also increase whole-body insulin sensitivity. To further characterize the relationship between plasma adiponectin concentration and insulin sensitivity in humans, we examined 1) the cross-sectional association between plasma adiponectin...... concentration and skeletal muscle IR tyrosine phosphorylation and 2) the prospective effect of plasma adiponectin concentration at baseline on change in insulin sensitivity. Fasting plasma adiponectin concentration, body composition (hydrodensitometry or dual energy X-ray absorptiometry), insulin sensitivity...... (insulin-stimulated glucose disposal, hyperinsulinemic clamp), and glucose tolerance (75-g oral glucose tolerance test) were measured in 55 Pima Indians (47 men and 8 women, aged 31 +/- 8 years, body fat 29 +/- 8% [mean +/- SD]; 50 with normal glucose tolerance, 3 with impaired glucose tolerance, and 2...

  14. INHIBITION OF PROTEIN TYROSINE PHOSPHATASE ACTIVITY MEDIATES EPIDERMAL GROWTH FACTOR RECEPTOR SIGNALING IN HUMAN AIRWAY EPITHELIAL CELLS

    Science.gov (United States)

    Epidemiological studies have implicated zinc in the toxicity of ambient particulate matter (PM) inhalation. We previously showed that exposure to metal-laden PM inhibits protein tyrosine phosphatase (PTP) activity in human primary bronchial epithelial cells (HAEC) and leads t...

  15. Receptor protein tyrosine phosphatase alpha activates Src-family kinases and controls integrin-mediated responses in fibroblasts

    DEFF Research Database (Denmark)

    Su, J; Muranjan, M; Sap, J

    1999-01-01

    RPTPalpha-/- mice had impaired tyrosine kinase activity of both c-Src and Fyn, and this was accompanied by a concomitant increase in c-Src Tyr527 phosphorylation. RPTPalpha-/- fibroblasts also showed a reduction in the rate of spreading on fibronectin substrates, a trait that is a phenocopy of the effect of...... tyrosine kinases, the activity of which is tightly controlled by inhibitory phosphorylation of a carboxyterminal tyrosine residue (Tyr527 in chicken c-Src); this phosphorylation induces the kinases to form an inactive conformation. Whereas the identity of such inhibitory Tyr527 kinases has been well...... inactivation of the c-src gene. In response to adhesion on a fibronectin substrate, RPTPalpha-/- fibroblasts also exhibited characteristic deficiencies in integrin-mediated signalling responses, such as decreased tyrosine phosphorylation of the c-Src substrates Fak and p 130(cas), and reduced activation of...

  16. Metabolic behavior of cell surface biotinylated proteins

    International Nuclear Information System (INIS)

    The turnover of proteins on the surface of cultured mammalian cells was measured by a new approach. Reactive free amino or sulfhydryl groups on surface-accessible proteins were derivatized with biotinyl reagents and the proteins solubilized from culture dishes with detergent. Solubilized, biotinylated proteins were then adsorbed onto streptavidin-agarose, released with sodium dodecyl sulfate and mercaptoethanol, and separated on polyacrylamide gels. Biotin-epsilon-aminocaproic acid N-hydroxysuccinimide ester (BNHS) or N-biotinoyl-N'-(maleimidohexanoyl)hydrazine (BM) were the derivatizing agents. Only 10-12 bands were adsorbed onto streptavidin-agarose from undervatized cells or from derivatized cells treated with free avidin at 4 degrees C. Two-dimensional isoelectric focusing-sodium dodecyl sulfate gel electrophoresis resolved greater than 100 BNHS-derivatized proteins and greater than 40 BM-derivatized proteins. There appeared to be little overlap between the two groups of derivatized proteins. Short-term pulse-chase studies showed an accumulation of label into both groups of biotinylated proteins up until 1-2 h of chase and a rapid decrease over the next 1-5 h. Delayed appearance of labeled protein at the cell surface was attributed to transit time from site of synthesis. The unexpected and unexplained rapid disappearance of pulse-labeled proteins from the cell surface was invariant for all two-dimensionally resolved proteins and was sensitive to temperature reduction to 18 degrees C. Long-term pulse-chase experiments beginning 4-8 h after the initiation of chase showed the disappearance of derivatized proteins to be a simple first-order process having a half-life of 115 h in the case of BNHS-derivatized proteins and 30 h in the case of BM-derivatized proteins

  17. The human gene for neurotrophic tyrosine kinase receptor type 2 (NTRK2) is located on chromosome 9 but is not the familial dysautonomia gene

    Energy Technology Data Exchange (ETDEWEB)

    Slaugenhaupt, S.A. [Massachusetts General Hospital, Boston, MA (United States)]|[Harvard Medical School, Boston, MA (United States); Liebert, C.B.; Lucente, D.E. [Massachusetts General Hospital, Boston, MA (United States)] [and others

    1995-02-10

    The neurotrophic tyrosine kinase receptor type 2 (NTRK2) gene is a member of the trk family of tyrosine protein kinases, which encode receptors for the nerve growth factor-related proteins known as neurotrophins. The neurotrophins and their receptors have long been considered candidate genes for familial dysautonomia (FD), a hereditary sensory neuropathy resulting from the congenital loss of both sensory and autonomic neurons. The DYS gene has recently been mapped to human chromosome 9q31-q33, and therefore we set out to determine the chromosomal localization of the candidate gene NTRK2. A mouse trkB probe was hybridized to both somatic cell hybrids containing human chromosome 9 and a human chromosome 9 flow-sorted cosmid library. The human homologue of trkB, NTRK2, was assigned to chromosome 9. To localize the NTRK2 gene further, a dinucleotide repeat polymorphism was identified within a cosmid that contains NTRK2 exon sequences. This marker was genotyped in the CEPH reference pedigrees and places the NTRK2 gene near D9S1 on the proximal long arm of human chromosome 9. The NTRK2 gene is located approximately 22 cm proximal to DYS and shows several recombinants in disease families. Therefore, the NTRK2 gene can now be excluded as a candidate gene for familial dysautonomia. 18 refs., 1 fig.

  18. Research Progress on Resistance Mechanisms of Epidermal Growth Factor ReceptorTyrosine Kinase Inhibitors in Non-small Cell Lung Cancer

    Directory of Open Access Journals (Sweden)

    Yuan LI

    2012-02-01

    Full Text Available With a greater understanding of tumor biology, novel molecular-targeted strategies that block cancer progression pathways have been evaluated as a new therapeutic approach for treating non-small cell lung cancer (NSCLC. Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs, such as gefitinib and erlotinib, show favorable response to EGFR mutant lung cancer in some populations of NSCLC patients. However, the efficacy of EGFR-TKIs is limited by either primary (de novo or acquired resistance after therapy. This review will focus on recently identified mechanisms of primary and acquired resistance to EGFR TKIs and strategies currently being employed to overcome resistance.

  19. Inhibiting receptor tyrosine kinase AXL with small molecule inhibitor BMS-777607 reduces glioblastoma growth, migration, and invasion in vitro and in vivo

    OpenAIRE

    Onken, J.; Torka, R.; Korsing, S; J Radke; Krementeskaia, I.; M. Nieminen; Bai, X.; A. Ullrich; Heppner, F.; Vajkoczy, P.

    2016-01-01

    Purpose: Receptor tyrosine kinase AXL (RTK-AXL) is regarded as suitable target in glioma therapy. Here we evaluate the anti-tumoral effect of small molecule inhibitor BMS-777607 targeting RTK-AXL in a preclinical glioma model and provide evidence that RTK-AXL is expressed and phosphorylated in primary and recurrent glioblastoma multiforme (GBM). Experimental design: We studied the impact of BMS-777607 targeting RTK-AXL in GBM models in vitro and in vivo utilizing glioma cells SF126 and U118MG...

  20. Central Role of the Threonine Residue within the p+1 Loop of Receptor Tyrosine Kinase in STAT3 Constitutive Phosphorylation in Metastatic Cancer Cells

    OpenAIRE

    Yuan, Zheng-long; Guan, Ying-jie; Wang, Lijuan; Wei, Wenyi; Kane, Agnes B.; Chin, Y. Eugene

    2004-01-01

    The receptor tyrosine kinases (RTKs) RET, MET, and RON all carry the Metp+1loop→Thr point mutation (i.e., 2B mutation), leading to the formation of tumors with high metastatic potential. Utilizing a novel antibody array, we identified constitutive phosphorylation of STAT3 in cells expressing the 2B mutation but not wild-type RET. MET or RON with the 2B mutation also constitutively phosphorylated STAT3. Members of the EPH, the only group of wild-type RTK that carry Thrp+1loop residue, are ofte...

  1. Transformation and scattering activities of the receptor tyrosine kinase RON/Stk in rodent fibroblasts and lack of regulation by the jaagsiekte sheep retrovirus receptor, Hyal2

    International Nuclear Information System (INIS)

    The envelope (Env) protein of jaagsiekte sheep retrovirus (JSRV) can transform cells in culture and is likely to be the main factor responsible for lung cancer induction by JSRV in animals. A recent report indicates that the epithelial-cell transforming activity of JSRV Env depends on activation of the cell-surface receptor tyrosine kinase Mst1r (called RON for the human and Stk for the rodent orthologs). In the immortalized line of human epithelial cells used (BEAS-2B cells), the virus receptor Hyal2 was found to bind to and suppress the activity of RON. When Env was expressed it bound to Hyal2 causing its degradation, release of RON activity from Hyal2 suppression, and activation of pathways resulting in cell transformation. Due to difficulty with reproducibility of the transformation assay in BEAS-2B cells, we have used more tractable rodent fibroblast models to further study Hyal2 modulation of RON/Stk transforming activity and potential effects of Hyal2 on RON/Stk activation by its natural ligand, macrophage stimulating protein (MSP). We did not detect transformation of NIH 3T3 cells by plasmids expressing RON or Stk, but did detect transformation of 208F rat fibroblasts by these plasmids at a very low rate. We were able to isolate 208F cell clones that expressed RON or Stk and that showed changes in morphology indicative of transformation. The parental 208F cells did not respond to MSP but 208F cells expressing RON or Stk showed obvious increases in scattering/transformation in response to MSP. Human Hyal2 had no effect on the basal or MSP-induced phenotypes of RON-expressing 208F cells, and human, mouse or rat Hyal2 had no effect on the basal or MSP-induced phenotypes of Stk-expressing 208F cells. We have shown that RON or Stk expression in 208F rat fibroblasts results in a transformed phenotype that is enhanced by addition of the natural ligand for these proteins, MSP. Hyal2 does not directly modulate the basal or MSP-induced RON/Stk activity, although it

  2. Regulation of Src family kinases involved in T cell receptor signaling by protein-tyrosine phosphatase CD148

    Czech Academy of Sciences Publication Activity Database

    Štěpánek, Ondřej; Kalina, T.; Dráber, Peter; Skopcová, Tereza; Svojgr, K.; Angelisová, Pavla; Hořejší, Václav; Weiss, A.; Brdička, Tomáš

    2011-01-01

    Roč. 286, č. 25 (2011), s. 22101-22112. ISSN 0021-9258 R&D Projects: GA MŠk 2B06064; GA MŠk 1M0506 Institutional research plan: CEZ:AV0Z50520514 Keywords : CD148 * tyrosine phosphatase * Src family kinases Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.773, year: 2011

  3. Internalization and down-regulation of the human epidermal growth factor receptor are regulated by the carboxyl-terminal tyrosines

    DEFF Research Database (Denmark)

    Helin, K; Beguinot, L

    1991-01-01

    in cells expressing the triple point mutant EGF-R can be attributed mainly to a slower removal from the cell surface. Our results show that in the full-length EGF-R all three C-terminal tyrosines are necessary for rapid internalization, suggesting that autophosphorylation is required for efficient...

  4. The human epidermal growth factor receptor (EGFR gene in European patients with advanced colorectal cancer harbors infrequent mutations in its tyrosine kinase domain

    Directory of Open Access Journals (Sweden)

    Delvenne Philippe

    2011-10-01

    Full Text Available Abstract Background The epidermal growth factor receptor (EGFR, a member of the ErbB family of receptors, is a transmembrane tyrosine kinase (TK activated by the binding of extracellular ligands of the EGF-family and involved in triggering the MAPK signaling pathway, which leads to cell proliferation. Mutations in the EGFR tyrosine kinase domain are frequent in non-small-cell lung cancer (NSCLC. However, to date, only very few, mainly non-European, studies have reported rare EGFR mutations in colorectal cancer (CRC. Methods We screened 236 clinical tumor samples from European patients with advanced CRC by direct DNA sequencing to detect potential, as yet unknown mutations, in the EGFR gene exons 18 to 21, mainly covering the EGFR TK catalytic domain. Results EGFR sequences showed somatic missense mutations in exons 18 and 20 at a frequency of 2.1% and 0.4% respectively. Somatic SNPs were also found in exons 20 and 21 at a frequency of about 3.1% and 0.4% respectively. Of these mutations, four have not yet been described elsewhere. Conclusions These mutation frequencies are higher than in a similarly sized population characterized by Barber and colleagues, but still too low to account for a major role played by the EGFR gene in CRC.

  5. Pulmonary adenocarcinoma in situ: analyses of a large series with reference to smoking, driver mutations, and receptor tyrosine kinase pathway activation.

    Science.gov (United States)

    Sato, Seijiro; Motoi, Noriko; Hiramatsu, Miyako; Miyauchi, Eisaku; Ono, Hiroshi; Saito, Yuichi; Nagano, Hiroko; Ninomiya, Hironori; Inamura, Kentaro; Uehara, Hirofumi; Mun, Mingyon; Sakao, Yukinori; Okumura, Sakae; Tsuchida, Masanori; Ishikawa, Yuichi

    2015-07-01

    Lung adenocarcinomas in situ (AISs) often occur in individuals who have never smoked, although smoking is one of the main causes of lung cancer. To characterize AIS and, in particular, determine how AIS might be related to smoking, we collected a large number of AIS cases and examined clinicopathologic features, EGFR and KRAS mutation status, and activation status of receptor tyrosine kinase downstream signal pathways, including pAkt, pERK, and pStat3, using immunohistochemistry. We identified 110 AISs (36 smokers and 74 nonsmokers) among 1549 adenocarcinomas resected surgically during 1995 to 2010. Between the AIS of smokers and nonsmokers, only the sex ratio was significantly different; all the other clinicopathologic factors including TTF-1 and driver mutations were not significantly different: EGFR and KRAS mutation rates (smokers:nonsmokers) were 61:58 (%) (P=0.7) and 6.1:1.4 (%) (P=0.2), respectively, whereas, in invasive adenocarcinomas, the rates were 41:69 (%) (P80% were positive, with no significant differences between smokers and nonsmokers with AIS. Mucinous AIS (n=8) rarely harbored KRAS mutations and expressed significantly less pStat3 (Plineage, driver mutations, and receptor tyrosine kinase pathway activation. Our results suggest that smoking is not a major cause of AIS. Rather, smoking may play a role in progression of AIS to invasive adenocarcinoma with AIS features. PMID:25970685

  6. Defects of tyrosine289phenylalanine mutation on binding and functional properties of the human tachykinin NK2 receptor stably expressed in chinese hamster ovary cells.

    Science.gov (United States)

    Renzetti, A R; Catalioto, R M; Carloni, C; Criscuoli, M; Cucchi, P; Giolitti, A; Zappitelli, S; Rotondaro, L; Maggi, C A

    1999-04-15

    A point mutation was made at position 289 in the transmembrane segment 7 of the human tachykinin NK2 receptor to yield a tyrosine/phenylalanine (Tyr/Phe) substitution. Chinese hamster ovary cells stably transfected with the wild-type or Tyr289Phe mutant NK2 receptor both bound neurokinin A (NKA) and the synthetic NK2 receptor-selective agonists, GR 64349 and [betaAla8]NKA(4-10), with high and even affinities. Neurokinin B (NKB) and substance P (SP) also displayed sizeable binding affinities, albeit with lower affinity as compared to NKA. In a functional assay (production of inositol-1,4,5-trisphosphate, IP3), NKA, GR 64349, and [betaAla8]INKA(4-10) stimulated IP3 accumulation via the wild-type and mutant receptors with similar potencies. On the other hand, NKB and SP exhibited a dramatic reduction in their agonist efficacies at the mutant receptor, NKB acting as a partial agonist (maximum effect = 50% of the response to NKA) and SP being totally inactive. The results obtained with phenoxybenzamine inactivation experiments indicated that a large and similar receptor reserve existed for both the wild-type and the mutant receptor. SP, which displayed sizeable binding affinity for the mutant receptor but did not stimulate IP3 accumulation, antagonized the agonist effect of NKA. The antagonist action of SP at the mutant NK2 receptor cannot be ascribed to receptor internalization. The Tyr/Phe replacement at position 289 markedly reduced the binding affinity and antagonist potency of the non-peptide ligand, SR 48968, without affecting the binding affinity and antagonist potency of the bicyclic peptide antagonist MEN 11420. The results indicate that the hydroxyl radical function of Tyr289 in transmembrane segment 7 of the human NK2 receptor is, directly or indirectly, involved in stimulus transduction when the NK2 receptor is occupied by NKB or SP, but not when using NKA or NK2 receptor-selective agonists. PMID:10086323

  7. Src homology 2 domain-based high throughput assays for profiling downstream molecules in receptor tyrosine kinase pathways.

    Science.gov (United States)

    Yaoi, Takuro; Chamnongpol, Sangpen; Jiang, Xin; Li, Xianqiang

    2006-05-01

    Src homology 2 (SH2) domains are evolutionary conserved small protein modules that bind specifically to tyrosine-phosphorylated peptides. More than 100 SH2 domains have been identified in proteins encoded by the human genome. The binding specificity of these domains plays a critical role in signaling within the cell, mediating the relocalization and interaction of proteins in response to changes in tyrosine phosphorylation states. Here we developed an SH2 domain profiling method based on a multiplexed fluorescent microsphere assay in which various SH2 domains are used to probe the global state of tyrosine phosphorylation within a cell and to screen synthetic peptides that specifically bind to each SH2 domain. The multiplexed, fluorescent microsphere-based assay is a recently developed technology that can potentially detect a wide variety of interactions between biological molecules. We constructed 25-plex SH2 domain-GST fusion protein-conjugated fluorescent microsphere sets to investigate phosphorylation-mediated cell signaling through the specific binding of SH2 domains to activated target proteins. The response of HeLa, COS-1, A431, and 293 cells and four breast cancer cell lines to epidermal growth factor and insulin were quantitatively profiled using this novel microsphere-based, multiplexed, high throughput assay system. PMID:16477079

  8. Radiation inactivation experiments predict that a large aggregate form of the insulin receptor is a highly active tyrosine-specific protein kinase

    International Nuclear Information System (INIS)

    The technique of radiation inactivation has been used on a highly purified insulin receptor in order to determine the functional molecular size responsible for tyrosine-specific protein kinase activity. When both insulin binding and kinase activities were analyzed with the same receptor preparations, the functional size for kinase activity was found to be larger than that for insulin binding activity. The radiation inactivation curve for kinase activity was multiphasic. This indicates that at least two components contribute to total kinase activity. The average minimal functional size for the kinase was 370,000 +/- 60,000 daltons (n = 7) which corresponds to the alpha 2 beta 2 form of the insulin receptor. The average functional size for larger forms was estimated to be approximately 4 X 10(6) daltons. (To minimize the complexity of the model used in this analysis, we have analyzed the radiation inactivation curves of the insulin receptor kinase activity with a two-component model. However, we believe that the larger component, greater than 1 X 10(6) daltons, is probably not a single molecular weight species but rather represents a continuum of sizes or aggregates of the alpha 2 beta 2 form of the receptor.) These larger forms contributed 93% of the total activity. Mild reduction of the insulin receptor preparation with dithiothreitol (DTT) activated the total kinase activity by 3.5-fold. Under this condition, the minimal functional kinase size was 380,000 +/- 30,000 daltons (n = 6) while the average functional size for the larger forms was approximately 3 X 10(6) daltons

  9. Development of epidermal growth factor receptor tyrosine kinase inhibitors against EGFR T790M. Mutation in non small-cell lung carcinoma

    Directory of Open Access Journals (Sweden)

    Wang Yuli

    2016-01-01

    Full Text Available Individualized therapies targeting epidermal growth factor receptor (EGFR mutations show promises for the treatment of non small-cell lung carcinoma (NSCLC. However, disease progression almost invariably occurs 1 year after tyrosine kinase inhibitor (TKI treatment. The most prominent mechanism of acquired resistance involves the secondary EGFR mutation, namely EGFR T790M, which accounts for 50%–60% of resistant tumors. A large amount of studies have focused on the development of effective strategies to treat TKI-resistant EGFR T790M mutation in lung tumors. Novel generations of EGFR inhibitors are producing encouraging results in patients with acquired resistance against EGFR T790M mutation. This review will summarize the novel inhibitors, which might overcome resistance against EGFR T790M mutation.

  10. Epidermal growth factor receptor tyrosine kinase (EGFR-TK) mutation testing in adults with locally advanced or metastatic non-small cell lung cancer : a systematic review and cost-effectiveness analysis

    NARCIS (Netherlands)

    Westwood, Marie; Joore, Manuela; Whiting, Penny; van Asselt, Thea; Ramaekers, Bram; Armstrong, Nigel; Misso, Kate; Severens, Johan; Kleijnen, Jos

    2014-01-01

    BACKGROUND: Non-small cell lung cancer (NSCLC) is the most common form of lung cancer. Some epidermal growth factor receptor tyrosine kinase (EGFR-TK) mutations make tumours responsive to treatment with EGFR-TK inhibitors (EGFR-TKIs) but less responsive to treatment with standard chemotherapy. Patie

  11. Epidermal growth factor receptor tyrosine kinase (EGFR-TK) mutation testing in adults with locally advanced or metastatic non-small cell lung cancer: A systematic review and cost-effectiveness analysis

    NARCIS (Netherlands)

    M. Westwood (Marie); M.A. Joore (Manuela); P. Whiting (Penny); T. van Asselt (Thea); B.L.T. Ramaekers (Bram); N. Armstrong (Nigel); K. Misso (Kate); J.L. Severens (Hans); J. Kleijnen (Jos)

    2014-01-01

    markdownabstract__Abstract__ Background: Non-small cell lung cancer (NSCLC) is the most common form of lung cancer. Some epidermal growth factor receptor tyrosine kinase (EGFR-TK) mutations make tumours responsive to treatment with EGFR-TK inhibitors (EGFR-TKIs) but less responsive to treatment wit

  12. Expression of the recepteur d'originenantais receptor tyrosine kinase in non-small cell lung cancer and its clinical significance

    Institute of Scientific and Technical Information of China (English)

    HAN Wei-li; LI Wei-dong; HU Jian; RUSIDANMU Aizemaiti; CHEN Ling-fang; SHEN Ling; ZHENG Shu-sen

    2012-01-01

    Background Recepteur d'originenantais (RON) is a receptor tyrosine kinase (RTK) that belongs to the MET proto-oncogene family.The aim of this study was to investigate the expression of RON receptor tyrosine kinase in human non-small cell lung cancer (NSCLC) and its relationship with clinical pathology of NSCLC and prognosis.Methods RON protein expression by immunohistochemistry (IHC) in 96 NSCLC specimens was evaluated and compared with the clinical pathology and prognosis,and 20 para-neoplastic tissues were included as controls.RON mRNA and protein expression in 25 fresh tissue samples of lung cancer and 10 normal lung tissues were also analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.Results The rate of positive RON expression differed significantly between NSCLC tissues (55.2%,53/96) and para-neoplastic tissues (5%,1/20) (P <0.001).RON protein expression was not found to be associated with gender or age.However,RON expression positively correlated with clinical TNM stage (P=0.004),histological types (P=0.001),lymph node metastasis (P=0.012) and differentiation (P=0.035).RT-PCR and Western blotting analysis also confirmed that the expression of RON mRNA and protein was significantly increased in the NSCLC tissues versus normal tissues.In addition,RON expression was associated with a poor prognosis for patients with NSCLC (P=0.045).Conclus1ons The expression of RON protein and mRNA is significant in human NSCLC and low in para-neoplastic and normal tissues.Elevated RON expression may contribute to the occurrence,progression and metastasis of NSCLC,inferring that it could be useful as a new prognostic indicator for patients with NSCLC.

  13. The human cytomegalovirus UL11 protein interacts with the receptor tyrosine phosphatase CD45, resulting in functional paralysis of T cells.

    Directory of Open Access Journals (Sweden)

    Ildar Gabaev

    2011-12-01

    Full Text Available Human cytomegalovirus (CMV exerts diverse and complex effects on the immune system, not all of which have been attributed to viral genes. Acute CMV infection results in transient restrictions in T cell proliferative ability, which can impair the control of the virus and increase the risk of secondary infections in patients with weakened or immature immune systems. In a search for new immunomodulatory proteins, we investigated the UL11 protein, a member of the CMV RL11 family. This protein family is defined by the RL11 domain, which has homology to immunoglobulin domains and adenoviral immunomodulatory proteins. We show that pUL11 is expressed on the cell surface and induces intercellular interactions with leukocytes. This was demonstrated to be due to the interaction of pUL11 with the receptor tyrosine phosphatase CD45, identified by mass spectrometry analysis of pUL11-associated proteins. CD45 expression is sufficient to mediate the interaction with pUL11 and is required for pUL11 binding to T cells, indicating that pUL11 is a specific CD45 ligand. CD45 has a pivotal function regulating T cell signaling thresholds; in its absence, the Src family kinase Lck is inactive and signaling through the T cell receptor (TCR is therefore shut off. In the presence of pUL11, several CD45-mediated functions were inhibited. The induction of tyrosine phosphorylation of multiple signaling proteins upon TCR stimulation was reduced and T cell proliferation was impaired. We therefore conclude that pUL11 has immunosuppressive properties, and that disruption of T cell function via inhibition of CD45 is a previously unknown immunomodulatory strategy of CMV.

  14. A protein-binding domain, EH, identified in the receptor tyrosine kinase substrate Eps15 and conserved in evolution

    DEFF Research Database (Denmark)

    Wong, W T; Schumacher, C; Salcini, A E;

    1995-01-01

    In this report we structurally and functionally define a binding domain that is involved in protein association and that we have designated EH (for Eps15 homology domain). This domain was identified in the tyrosine kinase substrate Eps15 on the basis of regional conservation with several heteroge......In this report we structurally and functionally define a binding domain that is involved in protein association and that we have designated EH (for Eps15 homology domain). This domain was identified in the tyrosine kinase substrate Eps15 on the basis of regional conservation with several...... heterogeneous proteins of yeast and nematode. The EH domain spans about 70 amino acids and shows approximately 60% overall amino acid conservation. We demonstrated the ability of the EH domain to specifically bind cytosolic proteins in normal and malignant cells of mesenchymal, epithelial, and hematopoietic...... origin. These observations prompted our search for additional EH-containing proteins in mammalian cells. Using an EH domain-specific probe derived from the eps15 cDNA, we cloned and characterized a cDNA encoding an EH-containing protein with overall similarity to Eps15; we designated this protein Eps15r...

  15. Small molecule receptor tyrosine kinase inhibitor of platelet-derived growth factor signaling (SU9518) modifies radiation response in fibroblasts and endothelial cells

    International Nuclear Information System (INIS)

    Several small receptor tyrosine kinase inhibitors (RTKI) have entered clinical cancer trials alone and in combination with radiotherapy or chemotherapy. The inhibitory spectrum of these compounds is often not restricted to a single target. For example Imatinib/Gleevec (primarily a bcr/abl kinase inhibitor) or SU11248 (mainly a VEGFR inhibitor) are also potent inhibitors of PDGFR and other kinases. We showed previously that PDGF signaling inhibition attenuates radiation-induced lung fibrosis in a mouse model. Here we investigate effects of SU9518, a PDGFR inhibitor combined with ionizing radiation in human primary fibroblasts and endothelial cells in vitro, with a view on utilizing RTKI for antifibrotic therapy. Protein levels of PDGFR-α/-β and phosphorylated PDGFR in fibroblasts were analyzed using western and immunocytochemistry assays. Functional proliferation and clonogenic assays were performed (i) to assess PDGFR-mediated survival and proliferation in fibroblasts and endothelial cells after SU9518 (small molecule inhibitor of PDGF receptor tyrosine kinase); (ii) to test the potency und selectivity of the PDGF RTK inhibitor after stimulation with PDGF isoforms (-AB, -AA, -BB) and VEGF+bFGF. In order to simulate in vivo conditions and to understand the role of radiation-induced paracrine PDGF secretion, co-culture models consisting of fibroblasts and endothelial cells were employed. In fibroblasts, radiation markedly activated PDGF signaling as detected by enhanced PDGFR phosphorylation which was potently inhibited by SU9518. In fibroblast clonogenic assay, SU9518 reduced PDGF stimulated fibroblast survival by 57%. Likewise, SU9518 potently inhibited fibroblast and endothelial cell proliferation. In the co-culture model, radiation of endothelial cells and fibroblast cells substantially stimulated proliferation of non irradiated fibroblasts and vice versa. Importantly, the RTK inhibitor significantly inhibited this paracrine radiation-induced fibroblast and

  16. Sesquiterpene dimmer (DSF-27) inhibits the release of neuroinflammatory mediators from microglia by targeting spleen tyrosine kinase (Syk) and Janus kinase 2 (Jak2): Two major non-receptor tyrosine signaling proteins involved in inflammatory events

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Ke-Wu [State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191 (China); Wang, Shu [State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191 (China); Department of Medicinal Chemistry and Pharmaceutical Analysis, Logistics College of Chinese People' s Armed Police Forces, Tianjin 300162 (China); Dong, Xin; Jiang, Yong; Jin, Hong-Wei [State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191 (China); Tu, Peng-Fei, E-mail: pengfeitu@vip.163.com [State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191 (China)

    2014-03-15

    Non-receptor protein tyrosine kinases (NRPTKs)-dependent inflammatory signal transduction cascades play key roles in immunoregulation. However, drug intervention through NRPTKs-involved immunoregulation mechanism in microglia (the major immune cells of the central nervous system) has not been widely investigated. A main aim of the present study is to elucidate the contribution of two major NRPTKs (Syk and Jak2) in neuroinflammation suppression by a bioactive sesquiterpene dimmer (DSF-27). We found that LPS-stimulated BV-2 cells activated Syk and further initiated Akt/NF-κB inflammatory pathway. This Syk-dependent Akt/NF-κB inflammatory pathway can be effectively ameliorated by DSF-27. Moreover, Jak2 was activated by LPS, which was followed by transcriptional factor Stat3 activation. The Jak2/Stat3 signal was suppressed by DSF-27 through inhibition of Jak2 and Stat3 phosphorylation, promotion of Jak/Stat3 inhibitory factors PIAS3 expression, and down-regulation of ERK and p38 MAPK phosphorylation. Furthermore, DSF-27 protected cortical and mesencephalic dopaminergic neurons against neuroinflammatory injury. Taken together, our findings indicate NRPTK signaling pathways including Syk/NF-κB and Jak2/Stat3 cascades are potential anti-neuroinflammatory targets in microglia, and may also set the basis for the use of sesquiterpene dimmer as a therapeutic approach for neuroinflammation via interruption of these pathways. - Highlights: • Sesquiterpene dimmer DSF-27 inhibits inflammatory mediators' production in microglia. • Syk-dependent Akt/NF-κB pathway is important for DSF-27's anti-inflammation activity. • Jak2/Stat3 pathway is important for DSF-27's anti-inflammation activity. • Jak2/Stat3 signaling pathway is partly regulated by ERK and p38 MAPKs and PIAS3. • DSF-27 protects neurons against microglia-mediated neuroinflammatory injury.

  17. Estrogen Regulates MAPK-Related Genes through Genomic and Nongenomic Interactions between IGF-I Receptor Tyrosine Kinase and Estrogen Receptor-Alpha Signaling Pathways in Human Uterine Leiomyoma Cells.

    Science.gov (United States)

    Yu, Linda; Moore, Alicia B; Castro, Lysandra; Gao, Xiaohua; Huynh, Hoang-Long C; Klippel, Michelle; Flagler, Norris D; Lu, Yi; Kissling, Grace E; Dixon, Darlene

    2012-01-01

    Estrogen and growth factors play a major role in uterine leiomyoma (UtLM) growth possibly through interactions of receptor tyrosine kinases (RTKs) and estrogen receptor-alpha (ERα) signaling. We determined the genomic and nongenomic effects of 17β-estradiol (E(2)) on IGF-IR/MAPKp44/42 signaling and gene expression in human UtLM cells with intact or silenced IGF-IR. Analysis by RT(2) Profiler PCR-array showed genes involved in IGF-IR/MAPK signaling were upregulated in UtLM cells by E(2) including cyclin D kinases, MAPKs, and MAPK kinases; RTK signaling mediator, GRB2; transcriptional factors ELK1 and E2F1; CCNB2 involved in cell cycle progression, proliferation, and survival; and COL1A1 associated with collagen synthesis. Silencing (si)IGF-IR attenuated the above effects and resulted in upregulation of different genes, such as transcriptional factor ETS2; the tyrosine kinase receptor, EGFR; and DLK1 involved in fibrosis. E(2) rapidly activated IGF-IR/MAPKp44/42 signaling nongenomically and induced phosphorylation of ERα at ser118 in cells with a functional IGF-IR versus those without. E(2) also upregulated IGF-I gene and protein expression through a prolonged genomic event. These results suggest a pivotal role of IGF-IR and possibly other RTKs in mediating genomic and nongenomic hormone receptor interactions and signaling in fibroids and provide novel genes and targets for future intervention and prevention strategies. PMID:23094148

  18. Physical and functional association of the cbl protooncogen product with an src-family protein tyrosine kinase, p53/56lyn, in the B cell antigen receptor-mediated signaling.

    Science.gov (United States)

    Tezuka, T; Umemori, H; Fusaki, N; Yagi, T; Takata, M; Kurosaki, T; Yamamoto, T

    1996-02-01

    To identify novel signal transducers involved in signaling mediated by the Src-family protein tyrosine kinases (PTKs), we used a yeast two-hybrid system with a probe corresponding to the regulatory region of p56lyn, a member of Src-family PTKs. One of the isolated clones contained the COOH-terminal 470 amino acid residues of p120c-cbl, the product of the cellular homologue of the v-cbl retroviral oncogene. p120c-cbl is a cytoplasmic protein with nuclear protein-like motifs. Here we show in vivo association of p120c-cbl with p53/56lyn. After stimulation of the B cell antigen receptor (BCR), p120c-cbl was rapidly tyrosine phosphorylated. Studies with lyn- or syk-negative chicken B cells demonstrated that p53/56lyn, but not p72syk, was crucial for tyrosine phosphorylation of p120c-cbl upon stimulation of the BCR. We also show the importance of p59fyn in tyrosine phosphorylation of p120c-cbl in the T-cell receptor-mediated signaling using fyn-overexpressing T cell hybridomas and splenic T cells from fyn-deficient mice. These results suggest that p120c-cbl is an important substrate of Src-family PTKs in the intracellular signaling mediated by the antigen receptors PMID:8627181

  19. Activating Mutations and/or Expression Levels of Tyrosine Kinase Receptors GRB7, RAS, and BRAF in Testicular Germ Cell Tumors

    Directory of Open Access Journals (Sweden)

    Alan McIntyre

    2005-12-01

    Full Text Available Amplification and/or overexpression of genes encoding tyrosine kinase receptors KIT and ERBB2 have been reported in testicular germ cell tumors (TGCTs. These receptors can bind the adaptor molecule GRB7 encoded by a gene adjacent to ERBB2 at 17q12, a region also frequently gained in TGCTs. GRB7 binding may be involved in the activation of RAS signaling and KRAS2 maps to 12p, which is constitutively gained in TGCT and lies within a minimum overlapping region of amplification at 12pl1.2–12.1, a region we have previously defined. RAS proteins activate BRAF, and activating mutations of genes encoding these proteins have been described in various tumors. Here we determine the relationships between expression levels and activating mutations of these genes in a series of 65 primary TGCTs and 4 TCGT cell lines. High levels of expression and activating mutations in RAS were mutually exclusive events, and activating mutations in RAS were only identified in the seminoma subtype. Mutations in BRAF were not identified. Increased ERBB2 expression was associated with differentiated nonseminoma histology excised from lymph nodes postchemotherapy. Mutation, elevated expression, and correlations between expression levels of KRAS2, GRB7, and KIT are consistent with their involvement in the development of TGCTs.

  20. Involvement of β3A Subunit of Adaptor Protein-3 in Intracellular Trafficking of Receptor-like Protein Tyrosine Phosphatase PCP-2

    Institute of Scientific and Technical Information of China (English)

    Hui DONG; Hong YUAN; Weirong JIN; Yan SHEN; Xiaojing XU; Hongyang WANG

    2007-01-01

    PCP-2 is a human receptor-like protein tyrosine phosphatase and a member of the MAM domain family cloned in human pancreatic adenocarcinoma cells. Previous studies showed that PCP-2 directly interacted with β-catenin through the juxtamembrane domain, dephosphorylated β-catenin and played an important role in the regulation of cell adhesion. Recent study showed that PCP-2 was also involved in the repression of β-catenin-induced transcriptional activity. Here we describe the interactions of PCP-2 with the β3A subunit of adaptor protein (AP)-3 and sorting nexin (SNX) 3. These protein complexes were detected using the yeast two-hybrid assay with the juxtamembrane and membrane-proximal catalytic domain of PCP-2 as "bait". Both AP-3 and SNX3 are molecules involved in intracellular trafficking of membrane receptors. The association between the β3A subunit of AP-3 and PCP-2 was further confirmed in mammalian cells. Our results suggested a possible mechanism of intracellular trafficking of PCP-2 mediated by AP-3 and SNX3 which might participate in the regulation of PCP-2 functions.

  1. Mapping of the receptor protein-tyrosine kinase 10 to human chromosome 1q21-q23 and mouse chromosome 1H1-5 by fluorescence in situ hybridization

    Energy Technology Data Exchange (ETDEWEB)

    Edelhoff, S.; Disteche, C.M. [Univ. of Washington School of Medicine, Seattle, WA (United States); Lai, C. [Scripps Research Inst., LaJolla, CA (United States)

    1995-01-01

    Receptor protein-tyrosine kinases (PTKs) play a critical role in the transduction of signals important to cell growth, differentiation, and survival. Mutations affecting the expression of receptor PTK genes have been associated with a number of vertebrate and invertebrate developmental abnormalities, and the aberrant regulation of tyrosine phosphorylation is implicated in a variety of neoplasias. One estimate suggests that approximately 100 receptor PTK genes exist in the mammalian genome, about half of which have been identified. The tyro-10 receptor protein-tyrosine kinase, first identified in a PCR-based survey for novel tyrosine kinases in the rat nervous system, defines a new subfamily of PTKs. It exhibits a catalytic domain most closely related to those found in the trk PTK receptor subfamily, which transduces signals for nerve growth factor and the related molecules brain-derived neurotrophic factor (BDNF), neurotrophin-3, and neurotrophin-4 (NT-3 and NT-4). Trk and the related PTK receptors trkB and trkC play a critical role in the neurotrophin-dependent survival of subsets of sensory and motor neurons. The predicted tyro-10 extracellular region is, however, distinct from that of the trk subfamily and is unique except for a domain shared with the blood coagulation factors V and VIII, thought to be involved in phospholipid binding. Although tyro-10 RNA is most abundant in heart and skeletal muscle in the adult rat, it is expressed in a wide variety of tissues, including the developing and mature brain. Tyro-10 appears identical to the murine TKT sequence reported by Karn et al. and exhibits a high degree of similarity with the CaK, DDR, and Nep PTKs. A ligand for tyro-10 has not yet been identified. 10 refs., 1 fig.

  2. Impaired degradation followed by enhanced recycling of epidermal growth factor receptor caused by hypo-phosphorylation of tyrosine 1045 in RBE cells

    International Nuclear Information System (INIS)

    Since cholangiocarcinoma has a poor prognosis, several epidermal growth factor receptor (EGFR)-targeted therapies with antibody or small molecule inhibitor treatment have been proposed. However, their effect remains limited. The present study sought to understand the molecular genetic characteristics of cholangiocarcinoma related to EGFR, with emphasis on its degradation and recycling. We evaluated EGFR expression and colocalization by immunoblotting and immunofluorescence, cell surface EGFR expression by fluorescence-activated cell sorting (FACS), and EGFR ubiquitination and protein binding by immunoprecipitation in the human cholangiocarcinoma RBE and immortalized cholangiocyte MMNK-1 cell lines. Monensin treatment and Rab11a depletion by siRNA were adopted for inhibition of EGFR recycling. Upon stimulation with EGF, ligand-induced EGFR degradation was impaired and the expression of phospho-tyrosine 1068 and phospho-p44/42 MAPK was sustained in RBE cells as compared with MMNK-1 cells. In RBE cells, the process of EGFR sorting for lysosomal degradation was blocked at the early endosome stage, and non-degradated EGFR was recycled to the cell surface. A disrupted association between EGFR and the E3 ubiquitin ligase c-Cbl, as well as hypo-phosphorylation of EGFR at tyrosine 1045 (Tyr1045), were also observed in RBE cells. In RBE cells, up-regulation of EGFR Tyr1045 phosphorylation is a potentially useful molecular alteration in EGFR-targeted therapy. The combination of molecular-targeted therapy determined by the characteristics of individual EGFR phosphorylation events and EGFR recycling inhibition show promise in future treatments of cholangiocarcinoma

  3. Modulation of the tyrosine kinase receptor Ret/glial cell-derived neurotrophic factor (GDNF) signaling: a new player in reproduction induced anterior pituitary plasticity?

    Science.gov (United States)

    Guillou, Anne; Romanò, Nicola; Bonnefont, Xavier; Le Tissier, Paul; Mollard, Patrice; Martin, Agnès O

    2011-02-01

    During gestation, parturition, and lactation, the endocrine axis of the dam must continually adapt to ensure the continual and healthy development of offspring. The anterior pituitary gland, which serves as the endocrine interface between the brain and periphery, undergoes adaptations that contribute to regulation of the reproductive axis. Growth factors and their receptors are potential candidates for intrapituitary and paracrine factors to participate in the functional and anatomical plasticity of the gland. We examined the involvement of the growth factor glial cell-derived neurotrophic factor (GDNF) and its receptor tyrosine kinase rearranged during transfection (Ret) in the physiological functional and anatomical plasticity of the anterior pituitary gland. We found that variations in both expression and subcellular localization of Ret during gestation and lactation are temporally correlated with changes in pituitary gland function. We showed that Ret/GDNF signaling could endorse two different functional roles depending on the physiological status. At the end of lactation and after weaning, Ret was colocalized with markers of apoptosis. We found that Ret could therefore act as a physiological dependence receptor capable of inducing apoptosis in the absence of GDNF. In addition, we identified the follicullostellate cell as a probable source for intrapituitary GDNF and proposed GDNF as a potential physiological modulator of endocrine cell function. During all stages studied, we showed that acute application of GDNF to pituitary slices was able to modulate both positively and negatively intracellular calcium activity. Altogether our results implicate Ret/GDNF as a potent pleiotropic factor able to influence pituitary physiology during a period of high plasticity. PMID:21239429

  4. Differential protein expression and oncogenic gene network link tyrosine kinase ephrin B4 receptor to aggressive gastric and gastroesophageal junction cancers.

    Science.gov (United States)

    Liersch-Löhn, Britta; Slavova, Nadia; Buhr, Heinz J; Bennani-Baiti, Idriss M

    2016-03-01

    Transmembrane tyrosine-kinase Ephrin receptors promote tumor progression and/or metastasis of several malignancies including leukemia, follicular lymphoma, glioma, malignant pleural mesothelioma, papillary thyroid carcinoma, sarcomas and ovarian, breast, bladder and non-small cell lung cancers. They also drive intestinal stem cell proliferation and positioning, control intestinal tissue boundaries and are involved in liver, pancreatic and colorectal cancers, indicating involvement in additional digestive system malignancies. We investigated the role of Ephrin-B4 receptor (EPHB4), and its ligand EFNB2, in gastric and gastroesophageal junction cancers in patient cohorts through computational, mathematical, molecular and immunohistochemical analyses. We show that EPHB4 is upregulated in preneoplastic gastroesophageal lesions and its expression further increased in gastroesophageal cancers in several independent cohorts. The closely related EPHB6 receptor, which also binds EFNB2, was downregulated in all tested cohorts, consistent with its tumor-suppressive properties in other cancers. EFNB2 expression is induced in esophageal cells by acidity, suggesting that gastroesophageal reflux disease (GERD) may constitute an early triggering event in activating EFNB2-EPHB4 signaling. Association of EPHB4 to both Barrett's esophagus and to advanced tumor stages, and its overexpression at the tumor invasion front and vascular endothelial cells intimate the notion that EPHB4 may be associated with multiple steps of gastroesophageal tumorigenesis. Analysis of oncogenomic signatures uncovered the first EPHB4-associated gene network (false discovery rate: 7 × 10(-90) ) composed of a five-transcription factor interconnected gene network that drives proliferation, angiogenesis and invasiveness. The EPHB4 oncogenomic network provides a molecular basis for its role in tumor progression and points to EPHB4 as a potential tumor aggressiveness biomarker and drug target in gastroesophageal

  5. Oral epidermal growth factor receptor tyrosine kinase inhibitors for the treatment of non-small cell lung cancer: comparative pharmacokinetics and drug-drug interactions.

    Science.gov (United States)

    Peters, Solange; Zimmermann, Stefan; Adjei, Alex A

    2014-09-01

    The development of orally active small molecule inhibitors of the epidermal growth factor receptor (EGFR) has led to new treatment options for non-small cell lung cancer (NSCLC). Patients with activating mutations of the EGFR gene show sensitivity to, and clinical benefit from, treatment with EGFR tyrosine kinase inhibitors (EGFR-TKls). First generation reversible ATP-competitive EGFR-TKls, gefitinib and erlotinib, are effective as first, second-line or maintenance therapy. Despite initial benefit, most patients develop resistance within a year, 50-60% of cases being related to the appearance of a T790M gatekeeper mutation. Newer, irreversible EGFR-TKls - afatinib and dacomitinib - covalently bind to and inhibit multiple receptors in the ErbB family (EGFR, HER2 and HER4). These agents have been mainly evaluated for first-line treatment but also in the setting of acquired resistance to first-generation EGFR-TKls. Afatinib is the first ErbB family blocker approved for patients with NSCLC with activating EGFR mutations; dacomitinib is in late stage clinical development. Mutant-selective EGFR inhibitors (AZD9291, CO-1686, HM61713) that specifically target the T790M resistance mutation are in early development. The EGFR-TKIs differ in their spectrum of target kinases, reversibility of binding to EGFR receptor, pharmacokinetics and potential for drug-drug interactions, as discussed in this review. For the clinician, these differences are relevant in the setting of polymedicated patients with NSCLC, as well as from the perspective of innovative anticancer drug combination strategies. PMID:25027951

  6. Highly conserved tyrosine 37 stabilizes desensitized states and restricts calcium permeability of ATP-gated P2X3 receptor

    Czech Academy of Sciences Publication Activity Database

    Jindřichová, Marie; Khafizov, K.; Skorinkin, A.; Fayuk, D.; Bart, G.; Zemková, Hana; Giniatullin, R.

    2011-01-01

    Roč. 119, č. 4 (2011), s. 676-685. ISSN 0022-3042 R&D Projects: GA AV ČR(CZ) IAA500110910 Institutional research plan: CEZ:AV0Z50110509 Keywords : purinergic receptors * desensitization * patch clamp Subject RIV: ED - Physiology Impact factor: 4.061, year: 2011

  7. Effect of dioxins on regulation of tyrosine hydroxylase gene expression by aryl hydrocarbon receptor: a neurotoxicology study

    OpenAIRE

    Akahoshi Eiichi; Yoshimura Seiko; Uruno Saeko; Ishihara-Sugano Mitsuko

    2009-01-01

    Abstract Background Dioxins and related compounds are suspected of causing neurological disruption. Epidemiological studies indicated that exposure to these compounds caused neurodevelopmental disturbances such as learning disability and attention deficit hyperactivity disorder, which are thought to be closely related to dopaminergic dysfunction. Although the molecular mechanism of their actions has not been fully investigated, a major participant in the process is aryl hydrocarbon receptor (...

  8. Versatile protein biotinylation strategies for potential high-throughput proteomics.

    Science.gov (United States)

    Lue, Rina Y P; Chen, Grace Y J; Hu, Yi; Zhu, Qing; Yao, Shao Q

    2004-02-01

    We present intein-mediated approaches for efficient biotinylation of proteins site-specifically. The reactive C-terminal thioester generated from intein-assisted protein splicing (either in vitro or in live cells) served as an attractive and exclusive site for attaching cysteine-containing biotin. Using these novel biotinylation strategies, we were able to efficiently biotinylate many proteins from different biological sources in a potentially high-throughput, high-content fashion. Some of these proteins were subsequently immobilized, in a very simple manner, onto different avidin-functionalized solid surfaces for applications such as protein microarray and surface plasmon resonance (SPR) spectroscopy, highlighting the numerous advantages of using biotin over other tags (e.g., GST, His-tag, etc.) as the method of choice in protein purification/immobilization. In addition, our intein-mediated strategies provided critical advantages over other protein biotinylation strategies in a number of ways. For the first time, we also successfully demonstrated that intein-mediated protein biotinylation proceeded adequately inside both bacterial and mammalian living cells, as well as in a cell-free protein synthesis system. Taken together, our results indicate the versatility of these intein-mediated strategies for potential high-throughput proteomics applications. They may also serve as useful tools for various biochemical and biophysical studies of proteins both in vitro and in vivo. PMID:14746473

  9. Biotinylated Y chromosome specific probe for human sexing

    International Nuclear Information System (INIS)

    Human chromosome DNA from WBC or fetus chorion samples were digested with Hae III and hybridized with biotinylated Y chromosome specific probe by Southern blotting, and hybridization signals were developed by the ABC (Avidin-biotin-alkaline phosphatase complex) system. The hybridization signal for 0.1 μg of male DNA could be detected clearly, while the signal for even 5 μg of female DNA could not. Parallel tests showed that the sexing results using 32P-labeled and biotinylated Y probe were identical. This suggests that the biotinylated Y probe can be applied to the determination of X-linked genetic diseases and sex abnormality, forensic analysis, sex determination of sportsmen and women, heterosexual transplanation of bone marrow, etc. It could become a convenient means for genetic diagnosis

  10. Anti-tumour effects of antibodies targeting the extracellular cysteine-rich region of the receptor tyrosine kinase EphB4.

    Science.gov (United States)

    Stephenson, Sally-Anne; Douglas, Evelyn L; Mertens-Walker, Inga; Lisle, Jessica E; Maharaj, Mohanan S N; Herington, Adrian C

    2015-04-10

    EphB4 is a membrane-bound receptor tyrosine kinase (RTK) commonly over-produced by many epithelial cancers but with low to no expression in most normal adult tissues. EphB4 over-production promotes ligand-independent signaling pathways that increase cancer cell viability and stimulate migration and invasion. Several studies have shown that normal ligand-dependent signaling is tumour suppressive and therefore novel therapeutics which block the tumour promoting ligand-independent signaling and/or stimulate tumour suppressive ligand-dependent signaling will find application in the treatment of cancer. An EphB4-specific polyclonal antibody, targeting a region of 200 amino acids in the extracellular portion of EphB4, showed potent in vitro anti-cancer effects measured by an increase in apoptosis and a decrease in anchorage independent growth. Peptide exclusion was used to identify the epitope targeted by this antibody within the cysteine-rich region of the EphB4 protein, a sequence defined as a potential ligand interacting interface. Addition of antibody to cancer cells resulted in phosphorylation and subsequent degradation of the EphB4 protein, suggesting a mechanism that is ligand mimetic and tumour suppressive. A monoclonal antibody which specifically targets this identified extracellular epitope of EphB4 significantly reduced breast cancer xenograft growth in vivo confirming that EphB4 is a useful target for ligand-mimicking antibody-based anti-cancer therapies. PMID:25831049

  11. Deletion of protein tyrosine phosphatase, non-receptor type 4 (PTPN4) in twins with a Rett syndrome-like phenotype.

    Science.gov (United States)

    Williamson, Sarah L; Ellaway, Carolyn J; Peters, Greg B; Pelka, Gregory J; Tam, Patrick P L; Christodoulou, John

    2015-09-01

    Rett syndrome (RTT), a neurodevelopmental disorder that predominantly affects females, is primarily caused by variants in MECP2. Variants in other genes such as CDKL5 and FOXG1 are usually associated with individuals who manifest distinct phenotypes that may overlap with RTT. Individuals with phenotypes suggestive of RTT are typically screened for variants in MECP2 and then subsequently the other genes dependent on the specific phenotype. Even with this screening strategy, there are individuals in whom no causative variant can be identified, suggesting that there are other novel genes that contribute to the RTT phenotype. Here we report a de novo deletion of protein tyrosine phosphatase, non-receptor type 4 (PTPN4) in identical twins with a RTT-like phenotype. We also demonstrate the reduced expression of Ptpn4 in a Mecp2 null mouse model of RTT, as well as the activation of the PTPN4 promoter by MeCP2. Our findings suggest that PTPN4 should be considered for addition to the growing list of genes that warrant screening in individuals with a RTT-like phenotype. PMID:25424712

  12. Enediyne lidamycin enhances the effect of epidermal growth factor receptor tyrosine kinase inhibitor, gefitinib, in epidermoid carcinoma A431 cells and lung carcinoma H460 cells.

    Science.gov (United States)

    Liu, Hong; Li, Liang; Li, Xing-Qi; Liu, Xiu-Jun; Zhen, Yong-Su

    2009-01-01

    Gefitinib, a low-molecular-weight epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is effective in a wide variety of tumor types. Preclinical studies have shown potentiated antitumor efficacies of this agent in combination with chemotherapy or radiotherapy. The antitumor antibiotic lidamycin (LDM) showed extremely potent cytotoxicity in vitro and marked therapeutic effect in vivo. In this report, the cytotoxic and biochemical activity of LDM and gefitinib on human epidermoid carcinoma A431 cells and human large cell lung cancer H460 cells as a single agent or in combination has been evaluated. In the MTT assay, LDM showed much more potent cytotoxicity than gefitinib to both cell lines. A431 cells with a highly EGFR-expressing level were more sensitive to gefitinib than H460 cells, which expressed EGFR at an intermediate level. LDM plus gefitinib showed potentiation of antiproliferative activity and apoptosis induction, which were associated with downregulation of EGFR signaling pathway and nuclear factor-kappa B expression, and the increase of cleaved poly (adenosine diphosphate-ribose) polymerase in the two cell lines, although to a lesser degree in H460 cells. Combined treatment induced G1 phase arrest similar to that of gefitinib alone in A431 cells and intensified G2/M phase accumulation in H460 cells. The above results indicate that LDM potentiates the effects of gefitinib in both gefitinib sensitive and less sensitive cells in association with enhanced inhibition of EGFR-dependent signaling. PMID:19342999

  13. Acquired resistance mechanisms to tyrosine kinase inhibitors in lung cancer with activating epidermal growth factor receptor mutation--diversity, ductility, and destiny.

    Science.gov (United States)

    Suda, Kenichi; Mizuuchi, Hiroshi; Maehara, Yoshihiko; Mitsudomi, Tetsuya

    2012-12-01

    Lung cancers that harbor somatic activating mutations in the gene for the epidermal growth factor receptor (EGFR) depend on mutant EGFR for their proliferation and survival; therefore, lung cancer patients with EGFR mutations often dramatically respond to orally available EGFR tyrosine kinase inhibitors (TKIs). However, emergence of acquired resistance is virtually inevitable, thus limiting improvement in patient outcomes. To elucidate and overcome this acquired resistance, multidisciplinary basic and clinical investigational approaches have been applied, using in vitro cell line models or samples obtained from lung cancer patients treated with EGFR-TKIs. These efforts have revealed several acquired resistance mechanisms and candidates, including EGFR secondary mutations (T790M and other rare mutations), MET amplification, PTEN downregulation, CRKL amplification, high-level HGF expression, FAS-NFκB pathway activation, epithelial-mesenchymal transition, and conversion to small cell lung cancer. Interestingly, cancer cells harbor potential destiny and ductility together in acquiring resistance to EGFR-TKIs, as shown in in vitro acquired resistance models. Molecular mechanisms of "reversible EGFR-TKI tolerance" that occur in early phase EGFR-TKI exposure have been identified in cell line models. Furthermore, others have reported molecular markers that can predict response to EGFR-TKIs in clinical settings. Deeper understanding of acquired resistance mechanisms to EGFR-TKIs, followed by the development of molecular target drugs that can overcome the resistance, might turn this fatal disease into a chronic disorder. PMID:22736441

  14. Oncogene swap as a novel mechanism of acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitor in lung cancer.

    Science.gov (United States)

    Mizuuchi, Hiroshi; Suda, Kenichi; Murakami, Isao; Sakai, Kazuko; Sato, Katsuaki; Kobayashi, Yoshihisa; Shimoji, Masaki; Chiba, Masato; Sesumi, Yuichi; Tomizawa, Kenji; Takemoto, Toshiki; Sekido, Yoshitaka; Nishio, Kazuto; Mitsudomi, Tetsuya

    2016-04-01

    Mutant selective epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), such as rociletinib and AZD9291, are effective for tumors with T790M secondary mutation that become refractory to first-generation EGFR-TKI. However, acquired resistance to these prospective drugs is anticipated considering the high adaptability of cancer cells and the mechanisms remain largely obscure. Here, CNX-2006 (tool compound of rociletinib) resistant sublines were established by chronic exposure of HCC827EPR cells harboring exon 19 deletion and T790M to CNX-2006. Through the analyses of these resistant subclones, we identified two resistant mechanisms accompanied by MET amplification. One was bypass signaling by MET amplification in addition to T790M, which was inhibited by the combination of CNX-2006 and MET-TKI. Another was loss of amplified EGFR mutant allele including T790M while acquiring MET amplification. Interestingly, MET-TKI alone was able to overcome this resistance, suggesting that oncogenic dependence completely shifted from EGFR to MET. We propose describing this phenomenon as an "oncogene swap." Furthermore, we analyzed multiple lesions from a patient who died of acquired resistance to gefitinib, then found a clinical example of an oncogene swap in which the EGFR mutation was lost and a MET gene copy was gained. In conclusion, an "oncogene swap" from EGFR to MET is a novel resistant mechanism to the EGFR-TKI. This novel mechanism should be considered in order to avoid futile inhibition of the original oncogene. PMID:26845230

  15. The receptor tyrosine kinase inhibitor amuvatinib (MP470) sensitizes tumor cells to radio- and chemo-therapies in part by inhibiting homologous recombination

    International Nuclear Information System (INIS)

    Background and purpose: RAD51 is a key protein involved in homologous recombination (HR) and a potential target for radiation- and chemotherapies. Amuvatinib (formerly known as MP470) is a novel receptor tyrosine kinase inhibitor that targets c-KIT and PDGFRα and can sensitize tumor cells to ionizing radiation (IR). Here, we studied amuvatinib mechanism on RAD51 and functional HR. Materials and methods: Protein and RNA analyses, direct repeat green fluorescent protein (DR-GFP) assay and polysomal fractioning were used to measure HR efficiency and global translation in amuvatinib-treated H1299 lung carcinoma cells. Synergy of amuvatinib with IR or mitomycin c (MMC) was assessed by clonogenic survival assay. Results: Amuvaninib inhibited RAD51 protein expression and HR. This was associated with reduced ribosomal protein S6 phosphorylation and inhibition of global translation. Amuvatinib sensitized cells to IR and MMC, agents that are selectively toxic to HR-deficient cells. Conclusions: Amuvatinib is a promising agent that may be used to decrease tumor cell resistance. Our work suggests that this is associated with decreased RAD51 expression and function and supports the further study of amuvatinib in combination with chemotherapy and radiotherapy.

  16. Hepatocyte growth factor reduces sensitivity to the epidermal growth factor receptor-tyrosine kinase inhibitor, gefitinib, in lung adenocarcinoma cells harboring wild-type EGFR

    Science.gov (United States)

    Yang, Hua; Wang, Rong; Peng, Shunli; Chen, Longhua; Li, Qi; Wang, Wei

    2016-01-01

    Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) therapy is an option for lung cancers harboring wild-type EGFR when chemotherapeutic reagents have failed. In this study, we found that the EGFR-TKI, gefitinib, modestly suppressed proliferation of the lung cancer cell lines, A549 and H358, which both harbor wild-type EGFR. Treatment with hepatocyte growth factor (HGF) reduced the sensitivity to gefitinib, whereas sensitivity was restored by treatment with an HGF antibody, a MET inhibitor, or depletion of MET but not ErbB3 gene. Moreover, both PI3K/mTOR inhibitors and MEK inhibitors suppressed proliferation of A549 cells, whereas only PI3K/mTOR inhibitors effectively suppressed cell viability of EGFR mutant PC-9 cells. Our findings suggest that HGF reduced the gefitinib sensitivity through MET and downstream PI3K and MAPK pathways. Combined use of EGFR-TKI and MET inhibitors or inhibition of downstream signaling molecules might be a better second or third line choice for a group of patients with advanced lung cancer harboring wild-type EGFR. PMID:26919104

  17. Kinome-wide shRNA Screen Identifies the Receptor Tyrosine Kinase AXL as a Key Regulator for Mesenchymal Glioblastoma Stem-like Cells

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    Peng Cheng

    2015-05-01

    Full Text Available Glioblastoma is a highly lethal cancer for which novel therapeutics are urgently needed. Two distinct subtypes of glioblastoma stem-like cells (GSCs were recently identified: mesenchymal (MES and proneural (PN. To identify mechanisms to target the more aggressive MES GSCs, we combined transcriptomic expression analysis and kinome-wide short hairpin RNA screening of MES and PN GSCs. In comparison to PN GSCs, we found significant upregulation and phosphorylation of the receptor tyrosine kinase AXL in MES GSCs. Knockdown of AXL significantly decreased MES GSC self-renewal capacity in vitro and inhibited the growth of glioblastoma patient-derived xenografts. Moreover, inhibition of AXL with shRNA or pharmacologic inhibitors also increased cell death significantly more in MES GSCs. Clinically, AXL expression was elevated in the MES GBM subtype and significantly correlated with poor prognosis in multiple cancers. In conclusion, we identified AXL as a potential molecular target for novel approaches to treat glioblastoma and other solid cancers.

  18. hnRNP A1-mediated translational regulation of the G quadruplex-containing RON receptor tyrosine kinase mRNA linked to tumor progression

    Science.gov (United States)

    Pierredon, Sandra; Le Bras, Morgane; Iacovoni, Jason S.; Teulade-Fichou, Marie-Paule; Favre, Gilles; Roché, Henri; Filleron, Thomas; Millevoi, Stefania; Vagner, Stéphan

    2016-01-01

    The expression and role of RNA binding proteins (RBPs) controlling mRNA translation during tumor progression remains largely uncharacterized. Analysis by immunohistochemistry of the expression of hnRNP A1, hnRNPH, RBM9/FOX2, SRSF1/ASF/SF2, SRSF2/SC35, SRSF3/SRp20, SRSF7/9G8 in breast tumors shows that the expression of hnRNP A1, but not the other tested RBPs, is associated with metastatic relapse. Strikingly, hnRNP A1, a nuclear splicing regulator, is also present in the cytoplasm of tumor cells of a subset of patients displaying exceedingly worse prognosis. Expression of a cytoplasmic mutant of hnRNP A1 leads to increased translation of the mRNA encoding the tyrosine kinase receptor RON/MTS1R, known for its function in tumor dissemination, and increases cell migration in vitro. hnRNP A1 directly binds to the 5′ untranslated region of the RON mRNA and activates its translation through G-quadruplex RNA secondary structures. The correlation between hnRNP A1 and RON tumoral expression suggests that these findings hold clinical relevance. PMID:26930004

  19. Significant blockade of multiple receptor tyrosine kinases by MGCD516 (Sitravatinib), a novel small molecule inhibitor, shows potent anti-tumor activity in preclinical models of sarcoma.

    Science.gov (United States)

    Patwardhan, Parag P; Ivy, Kathryn S; Musi, Elgilda; de Stanchina, Elisa; Schwartz, Gary K

    2016-01-26

    Sarcomas are rare but highly aggressive mesenchymal tumors with a median survival of 10-18 months for metastatic disease. Mutation and/or overexpression of many receptor tyrosine kinases (RTKs) including c-Met, PDGFR, c-Kit and IGF1-R drive defective signaling pathways in sarcomas. MGCD516 (Sitravatinib) is a novel small molecule inhibitor targeting multiple RTKs involved in driving sarcoma cell growth. In the present study, we evaluated the efficacy of MGCD516 both in vitro and in mouse xenograft models in vivo. MGCD516 treatment resulted in significant blockade of phosphorylation of potential driver RTKs and induced potent anti-proliferative effects in vitro. Furthermore, MGCD516 treatment of tumor xenografts in vivo resulted in significant suppression of tumor growth. Efficacy of MGCD516 was superior to imatinib and crizotinib, two other well-studied multi-kinase inhibitors with overlapping target specificities, both in vitro and in vivo. This is the first report describing MGCD516 as a potent multi-kinase inhibitor in different models of sarcoma, superior to imatinib and crizotinib. Results from this study showing blockade of multiple driver signaling pathways provides a rationale for further clinical development of MGCD516 for the treatment of patients with soft-tissue sarcoma. PMID:26675259

  20. Radiotherapy for asymptomatic brain metastasis in epidermal growth factor receptor mutant non-small cell lung cancer without prior tyrosine kinase inhibitors treatment: a retrospective clinical study

    International Nuclear Information System (INIS)

    Non-small cell lung cancer (NSCLC) with brain metastasis (BM) harboring an epidermal growth factor receptor (EGFR) mutation shows good response to tyrosine kinase inhibitors (TKIs). This study is to assess the appropriate timing of brain radiotherapy (RT) for asymptomatic BM in EGFR mutant NSCLC patients. There were 628 patients diagnosed with EGFR mutant NSCLC between October 2005 and December 2011. Treatment outcomes had been retrospectively evaluated in 96 patients with asymptomatic BM without prior TKI treatment. 39 patients received first-line brain RT, 23 patients received delayed brain RT, and 34 patients did not receive brain RT. With a median follow-up of 26 months, the 2-year OS was 40.6 %. Univariate analyses revealed that ECOG performance status (p = 0.006), other distant metastases (p = 0.002) and first line systemic treatment (p = 0.032) were significantly associated with overall survival (OS). Multivariate analyses revealed that other sites of distant metastases (p = 0.030) were prognostic factor. The timing of brain RT was not significantly related to OS (p = 0.246). The 2-year BM progression-free survival (PFS) was 26.9 %. Brain RT as first-line therapy failed to demonstrate a significant association with BM PFS (p = 0.643). First-line brain RT failed to improve long-term survival in TKI-naïve EGFR mutant NSCLC patients with asymptomatic BM. Prospective studies are needed to validate these clinical findings

  1. Postnatal Development of Brain-Derived Neurotrophic Factor (BDNF) and Tyrosine Protein Kinase B (TrkB) Receptor Immunoreactivity in Multiple Brain Stem Respiratory-Related Nuclei of the Rat

    OpenAIRE

    LIU, QIULI; Wong-Riley, Margaret T.T.

    2013-01-01

    Previously, we found a transient imbalance between suppressed excitation and enhanced inhibition in the respiratory network of the rat around postnatal days (P) 12–13, a critical period when the hypoxic ventilatory response is at its weakest. The mechanism underlying the imbalance is poorly understood. Brain-derived neurotrophic factor (BDNF) and its tyrosine protein kinase B (TrkB) receptors are known to potentiate glutamatergic and attenuate gamma-aminobutyric acid (GABA)ergic neurotransmis...

  2. Homozygosity for killer immunoglobin-like receptor haplotype A predicts complete molecular response to treatment with tyrosine kinase inhibitors in chronic myeloid leukemia patients.

    Science.gov (United States)

    La Nasa, Giorgio; Caocci, Giovanni; Littera, Roberto; Atzeni, Sandra; Vacca, Adriana; Mulas, Olga; Langiu, Marzia; Greco, Marianna; Orrù, Sandro; Orrù, Nicola; Floris, Andrea; Carcassi, Carlo

    2013-05-01

    Several recent reports suggest a possible role for killer immunoglobulin-like receptors (KIR) in the onset of chronic myeloid leukemia (CML) and response to therapy with tyrosine kinase inhibitors (TKIs). To explore this hypothesis, we studied KIRs and their human leukocyte antigen class I ligands in 59 consecutive patients with chronic-phase CML (mean age, 53 years; range, 23-81 years) and a group of 121 healthy control participants belonging to the same ethnic group as the patients. The 2-year cumulative incidence of complete molecular response, obtained after a median of 27 months (range, 4-52 months), was 51.2%. An increased frequency of the activating receptor KIR2DS1 (pm = 0.05) and a reduced frequency of the KIR-ligand combination KIR2DS2/2DL2 absent/C1 present (pm = 0.001) were significantly associated with CML. Moreover, KIR repertoires in patients appeared to influence response to TKI therapy. Homozygosity for KIR haplotype A (pm = 0.01), a decreased frequency of the inhibitory KIR gene KIR2DL2 (pm = 0.02), and low numbers of inhibitory KIR genes (pm = 0.05) were all significantly associated with achievement of complete molecular remission. These data suggest that a decrease in properly stimulated and activated NK cells might contribute to the occurrence of CML and indicate homozygosity for KIR haplotype A as a promising immunogenetic marker of complete molecular response that could help clinicians decide whether to withdraw treatment in patients with CML. PMID:23380384

  3. The structural insights of stem cell factor receptor (c-Kit interaction with tyrosine phosphatase-2 (Shp-2: An in silico analysis

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    Gurudutta Gangenahalli U

    2010-01-01

    Full Text Available Abstract Background Stem cell factor (SCF receptor c-Kit is recognized as a key signaling molecule, which transduces signals for the proliferation, differentiation and survival of stem cells. Binding of SCF to its receptor triggers transactivation, leading to the recruitment of kinases and phosphatases to the docking platforms of c-Kit catalytic domain. Tyrosine phosphatase-1 (Shp-1 deactivates/attenuates 'Kit' kinase activity. Whereas, Asp816Val mutation in the Kit activation loop transforms kinase domain to a constitutively activated state (switch off-to-on state, in a ligand-independent manner. This phenomenon completely abrogates negative regulation of Shp-1. To predict the possible molecular basis of interaction between c-Kit and Shp-1, we have performed an in silico protein-protein docking study between crystal structure of activated c-Kit (phosphorylated c-Kit and full length crystal structure of Shp-2, a close structural counterpart of Shp-1. Findings Study revealed a stretch of conserved amino acids (Lys818 to Ser821 in the Kit activation domain, which makes decisive H-bonds with N-sh2 and phosphotyrosine binding pocket residues of the phosphatase. These H-bonds may impose an inhibitory steric hindrance to the catalytic domain of c-Kit, there by blocking further interaction of the activation loop molecules with incoming kinases. We have also predicted a phosphotyrosine binding pocket in SH2 domains of Shp-1, which is found to be predominantly closer to a catalytic groove like structure in c-Kit kinase domain. Conclusions This study predicts that crucial hydrogen bonding between N-sh2 domain of Shp-1 and Kit activation loop can modulate the negative regulation of c-Kit kinase by Shp-1. Thus, this finding is expected to play a significant role in designing suitable gain-of-function c-Kit mutants for inducing conditional proliferation of hematopoietic stem cells.

  4. Effects of ketoconazole or rifampin on the pharmacokinetics of tivozanib hydrochloride, a vascular endothelial growth factor receptor tyrosine kinase inhibitor.

    Science.gov (United States)

    Cotreau, Monette M; Siebers, Nicholas M; Miller, James; Strahs, Andrew L; Slichenmyer, William

    2015-03-01

    The vascular endothelial growth factor (VEGF) pathway is associated with the promotion of endothelial cell proliferation, migration, and survival necessary for angiogenesis. VEGF and its three receptor isoforms are often overexpressed in many human solid tumors. Tivozanib is a potent, selective inhibitor of VEGF receptors 1, 2, and 3, with a long half-life. The purpose of these studies was to evaluate the effect of ketoconazole, a potent inhibitor of CYP3A4, and rifampin, a potent inducer of CYP3A4, on the pharmacokinetics of tivozanib. Two phase I, open-label, 2-period, single-sequence studies evaluated the effect of steady-state ketoconazole (NCT01363778) or rifampin (NCT01363804) on the pharmacokinetic profile, safety, and tolerability of a single oral 1.5-mg dose of tivozanib. Tivozanib was well tolerated in both studies. Steady-state ketoconazole did not cause a clinically significant change in the pharmacokinetics of a single dose of tivozanib; therefore, dosing of tivozanib with a CYP3A4 pathway inhibitor should not cause a clinically significant change in serum tivozanib levels. However, coadministration of tivozanib with rifampin caused a significant decrease in the area under the curve from 0 to infinity and half-life and an increase in clearance of tivozanib, which suggest increased clearance via the enhanced CYP3A4-mediated metabolism of tivozanib. PMID:27128217

  5. Tyrosylprotein sulfotransferase-1 and tyrosine sulfation of chemokine receptor 4 are induced by Epstein-Barr virus encoded latent membrane protein 1 and associated with the metastatic potential of human nasopharyngeal carcinoma.

    Directory of Open Access Journals (Sweden)

    Juan Xu

    Full Text Available The latent membrane protein 1 (LMP1, which is encoded by the Epstein-Barr virus (EBV, is an important oncogenic protein that is closely related to carcinogenesis and metastasis of nasopharyngeal carcinoma (NPC, a prevalent cancer in China. We previously reported that the expression of the functional chemokine receptor CXCR4 is associated with human NPC metastasis. In this study, we show that LMP1 induces tyrosine sulfation of CXCR4 through tyrosylprotein sulfotransferase-1 (TPST-1, an enzyme that is responsible for catalysis of tyrosine sulfation in vivo, which is likely to contribute to the highly metastatic character of NPC. LMP1 could induce tyrosine sulfation of CXCR4 and its associated cell motility and invasiveness in a NPC cell culture model. In contrast, the expression of TPST-1 small interfering RNA reversed LMP1-induced tyrosine sulfation of CXCR4. LMP1 conveys signals through the epidermal growth factor receptor (EGFR pathway, and EGFR-targeted siRNA inhibited the induction of TPST-1 by LMP1. We used a ChIP assay to show that EGFR could bind to the TPST-1 promoter in vivo under the control of LMP1. A reporter gene assay indicated that the activity of the TPST-1 promoter could be suppressed by deleting the binding site between EGFR and TPST-1. Finally, in human NPC tissues, the expression of TPST-1 and LMP1 was directly correlated and clinically, the expression of TPST-1 was associated with metastasis. These results suggest the up-regulation of TPST-1 and tyrosine sulfation of CXCR4 by LMP1 might be a potential mechanism contributing to NPC metastasis.

  6. Risk of treatment-related deaths with vascular endothelial growth factor receptor tyrosine kinase inhibitors: a meta-analysis of 41 randomized controlled trials

    Directory of Open Access Journals (Sweden)

    Hong SD

    2014-10-01

    Full Text Available Shaodong Hong,1,* Wenfeng Fang,1,* Wenhua Liang,1,* Yue Yan,1 Ting Zhou,1 Tao Qin,1 Xuan Wu,1 Yuxiang Ma,1 Yuanyuan Zhao,1 Yunpeng Yang,1 Zhihuang Hu,1 Cong Xue,1 Xue Hou,1 Yue Chen,2 Yan Huang,1 Hongyun Zhao,1 Li Zhang1 1State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, People's Republic of China; 2Medical School, University of South China, Hengyang, Hunan, People's Republic of China *These authors contributed equally to this work Background: Vascular endothelial growth factor receptor (VEGFR tyrosine kinase inhibitors (TKIs have widely been used in advanced cancer. However, these drugs may also lead to serious adverse events. The present meta-analysis aimed to determine the overall incidence and risk of deaths due to VEGFR-TKIs with more detailed subgroup analysis. Materials and methods: PubMed, Web of Science, and Cochrane databases were searched for randomized controlled trials (RCTs that compared VEGFR-TKIs with non-VEGFR-TKIs in the treatment of solid cancer. Pooled incidence, odds ratios (ORs and 95% confidence intervals (CIs were calculated using random-effects or fixed-effects models based on the heterogeneity of included trials. Results: A total of 14,139 participants from 41 RCTs were enrolled. The pooled incidence of death due to VEGFR-TKIs was 1.9% (95% CI: 1.6%–2.3% with an OR of 1.85 (95% CI: 1.33–2.58; P<0.01 when compared with control groups. On subgroup analysis, significantly increased risk of death was found in patients with nonsmall-cell lung cancer (OR: 2.37; 95% CI: 1.19–4.73; P=0.01 and colorectal cancer (OR: 2.84; 95% CI: 1.02–7.96; P=0.05. Among different VEGFR-TKIs, sorafenib and sunitinib had significant risk of death when compared with control arms, respectively. VEGFR-TKIs in combination with other antineoplastic agents, but not VEGFR-TKI monotherapy, significantly increased the risk of treatment

  7. Tyrosine phosphatases such as SHP-2 act in a balance with Src-family kinases in stabilization of postsynaptic clusters of acetylcholine receptors

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    Rüegg Markus A

    2007-07-01

    Full Text Available Abstract Background Development of neural networks requires that synapses are formed, eliminated and stabilized. At the neuromuscular junction (NMJ, agrin/MuSK signaling, by triggering downstream pathways, causes clustering and phosphorylation of postsynaptic acetylcholine receptors (AChRs. Postnatally, AChR aggregates are stabilized by molecular pathways that are poorly characterized. Gain or loss of function of Src-family kinases (SFKs disassembles AChR clusters at adult NMJs in vivo, whereas AChR aggregates disperse rapidly upon withdrawal of agrin from cultured src-/-;fyn-/- myotubes. This suggests that a balance between protein tyrosine phosphatases (PTPs and protein tyrosine kinases (PTKs such as those of the Src-family may be essential in stabilizing clusters of AChRs. Results We have analyzed the role of PTPs in maintenance of AChR aggregates, by adding and then withdrawing agrin from cultured myotubes in the presence of PTP or PTK inhibitors and quantitating remaining AChR clusters. In wild-type myotubes, blocking PTPs with pervanadate caused enhanced disassembly of AChR clusters after agrin withdrawal. When added at the time of agrin withdrawal, SFK inhibitors destabilized AChR aggregates but concomitant addition of pervanadate rescued cluster stability. Likewise in src-/-;fyn-/- myotubes, in which agrin-induced AChR clusters form normally but rapidly disintegrate after agrin withdrawal, pervanadate addition stabilized AChR clusters. The PTP SHP-2, known to be enriched at the NMJ, associated and colocalized with MuSK, and agrin increased this interaction. Specific SHP-2 knockdown by RNA interference reduced the stability of AChR clusters in wild-type myotubes. Similarly, knockdown of SHP-2 in adult mouse soleus muscle by electroporation of RNA interference constructs caused disassembly of pretzel-shaped AChR-rich areas in vivo. Finally, we found that src-/-;fyn-/- myotubes contained elevated levels of SHP-2 protein. Conclusion Our data

  8. Phase Ⅰ trial of icotinib, a novel epidermal growth factor receptor tyrosine kinase inhibitor, in Chinese patients with non-small cell lung cancer

    Institute of Scientific and Technical Information of China (English)

    WANG Han-ping; XIAO Yi; ZHANG Li; WANG Yin-xiang; TAN Fen-lai; XIA Ying; REN Guan-jun; HU Pei; JIANG Ji; WANG Meng-zhao

    2011-01-01

    Background The preclinical experiments and studies of congener drugs show icotinib, a new epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, can specifically bind to the tyrosine kinase domain of the EGFR, block the EGFR related signal, thereby inhibit the growth of tumor cell. The objective of this study was to investigate the safety, tolerability and dose-related biologic effects of icotinib in patients with non-small cell lung cancer (NSCLC) in a Chinese patient population.Methods This was an open-label, phase Ⅰ, dose escalation, safety/tolerability trial of oral icotinib (100 to 400 mg), administered twice per day for 28-continuous-day cycles until disease progression or undue toxiclty.Results Forty patients with stage ⅢB (15%) or Ⅳ (85%) NSCLC were included in the study. They had mainly adenocarcinoma (85%), with a performance status (PS) of 0 (45%) or 1 (55%) and less than half the patients (45%) had histories of smoking and all were pretreated by at least one regimen of chemotherapy. Patients were assigned to three dose levels of 150 mg b.i.d, 200 mg b.i.d, or 125 mg t.i.d. The follow-up periods ranged from 5 to 80 weeks. Adverse events were found in 35% patients, most of which were mild and reversible. The adverse events mainly occurred in the first 4 weeks and included rash (25%), diarrhea, nausea and abdominal distention. One definite interstitial lung disease (ILD) was found in a patient in the dose of 200 mg b.i.d. According to an 8-week assessment, one (2.5%) patient receiving 150 mg gained complete response (CR) that persisted for 44 weeks, seven (17.50%) patients had partial remission (PR), and 18 (45%) patients had stable disease (SD). The objective response including CR+PR was 20%. The median time of progression-free survival for the 40 patients was 20 weeks (range: 12 to 32 weeks). The response was not affected by pathological type, history of smoking, or numbers of previous therapeutic regimens. No relationship between dose

  9. Interaction Potential of the Multitargeted Receptor Tyrosine Kinase Inhibitor Dovitinib with Drug Transporters and Drug Metabolising Enzymes Assessed in Vitro

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    Johanna Weiss

    2014-12-01

    Full Text Available Dovitinib (TKI-258 is under development for the treatment of diverse cancer entities. No published information on its pharmacokinetic drug interaction potential is available. Thus, we assessed its interaction with important drug metabolising enzymes and drug transporters and its efficacy in multidrug resistant cells in vitro. P-glycoprotein (P-gp, MDR1, ABCB1 inhibition was evaluated by calcein assay, inhibition of breast cancer resistance protein (BCRP, ABCG2 by pheophorbide A efflux, and inhibition of organic anion transporting polypeptides (OATPs by 8-fluorescein-cAMP uptake. Inhibition of cytochrome P450 3A4, 2C19, and 2D6 was assessed by using commercial kits. Induction of transporters and enzymes was quantified by real-time RT-PCR. Possible aryl hydrocarbon receptor (AhR activating properties were assessed by a reporter gene assay. Substrate characteristics were evaluated by growth inhibition assays in cells over-expressing P-gp or BCRP. Dovitinib weakly inhibited CYP2C19, CYP3A4, P-gp and OATPs. The strongest inhibition was observed for BCRP (IC50 = 10.3 ± 4.5 μM. Among the genes investigated, dovitinib only induced mRNA expression of CYP1A1, CYP1A2, ABCC3 (coding for multidrug resistance-associated protein 3, and ABCG2 and suppressed mRNA expression of some transporters and drug metabolising enzymes. AhR reporter gene assay demonstrated that dovitinib is an activator of this nuclear receptor. Dovitinib retained its efficacy in cell lines over-expressing P-gp or BCRP. Our analysis indicates that dovitinib will most likely retain its efficacy in tumours over-expressing P-gp or BCRP and gives first evidence that dovitinib might act as a perpetrator drug in pharmacokinetic drug–drug interactions.

  10. Ginsenoside-Rg1 induces angiogenesis by the inverse regulation of MET tyrosine kinase receptor expression through miR-23a

    International Nuclear Information System (INIS)

    Therapeutic angiogenesis has been implicated in ischemic diseases and wound healing. Ginsenoside-Rg1 (Rg1), one of the most abundant active components of ginseng, has been demonstrated as an angiogenesis-stimulating compound in different models. There is increasing evidence implicating microRNAs (miRNAs), a group of non-coding RNAs, as important regulators of angiogenesis, but the role of microRNAs in Rg1-induced angiogenesis has not been fully explored. In this report, we found that stimulating endothelial cells with Rg1 could reduce miR-23a expression. In silico experiments predicted hepatocyte growth factor receptor (MET), a well-established mediator of angiogenesis, as the target of miR-23a. Transfection of the miR-23a precursor or inhibitor oligonucleotides validated the inverse relationship of miR-23a and MET expression. Luciferase reporter assays further confirmed the interaction between miR-23a and the MET mRNA 3′-UTR. Intriguingly, ginsenoside-Rg1 was found to increase MET protein expression in a time-dependent manner. We further demonstrated that ginsenoside-Rg1-induced angiogenic activities were indeed mediated through the down-regulation of miR-23a and subsequent up-regulation of MET protein expression, as confirmed by gain- and loss-of-function angiogenic experiments. In summary, our results demonstrated that ginsenoside-Rg1 could induce angiogenesis by the inverse regulation of MET tyrosine kinase receptor expression through miR-23a. This study has broadened our understanding of the non-genomic effects of ginsenoside-Rg1, and provided molecular evidence that warrant further development of natural compound as novel angiogenesis-promoting therapy. - Highlights: • Therapeutic angiogenesis has been implicated in ischemic diseases and wound healing. • Ginsenoside-Rg1 (Rg1) has been demonstrated as an angiogenesis-stimulating compound. • We found that Rg1 induces angiogenesis by decreasing miR-23a expression. • Hepatocyte growth factor receptor

  11. Ginsenoside-Rg{sub 1} induces angiogenesis by the inverse regulation of MET tyrosine kinase receptor expression through miR-23a

    Energy Technology Data Exchange (ETDEWEB)

    Kwok, Hoi-Hin [Dr. Gilbert Hung Ginseng Laboratory, Faculty of Science, Hong Kong Baptist University, Hong Kong SAR (China); Chan, Lai-Sheung [Department of Biology, Faculty of Science, Hong Kong Baptist University, Hong Kong SAR (China); Poon, Po-Ying [Dr. Gilbert Hung Ginseng Laboratory, Faculty of Science, Hong Kong Baptist University, Hong Kong SAR (China); Yue, Patrick Ying-Kit [Dr. Gilbert Hung Ginseng Laboratory, Faculty of Science, Hong Kong Baptist University, Hong Kong SAR (China); Department of Biology, Faculty of Science, Hong Kong Baptist University, Hong Kong SAR (China); Wong, Ricky Ngok-Shun, E-mail: rnswong@hkbu.edu.hk [Dr. Gilbert Hung Ginseng Laboratory, Faculty of Science, Hong Kong Baptist University, Hong Kong SAR (China); Department of Biology, Faculty of Science, Hong Kong Baptist University, Hong Kong SAR (China)

    2015-09-15

    Therapeutic angiogenesis has been implicated in ischemic diseases and wound healing. Ginsenoside-Rg{sub 1} (Rg{sub 1}), one of the most abundant active components of ginseng, has been demonstrated as an angiogenesis-stimulating compound in different models. There is increasing evidence implicating microRNAs (miRNAs), a group of non-coding RNAs, as important regulators of angiogenesis, but the role of microRNAs in Rg{sub 1}-induced angiogenesis has not been fully explored. In this report, we found that stimulating endothelial cells with Rg{sub 1} could reduce miR-23a expression. In silico experiments predicted hepatocyte growth factor receptor (MET), a well-established mediator of angiogenesis, as the target of miR-23a. Transfection of the miR-23a precursor or inhibitor oligonucleotides validated the inverse relationship of miR-23a and MET expression. Luciferase reporter assays further confirmed the interaction between miR-23a and the MET mRNA 3′-UTR. Intriguingly, ginsenoside-Rg{sub 1} was found to increase MET protein expression in a time-dependent manner. We further demonstrated that ginsenoside-Rg{sub 1}-induced angiogenic activities were indeed mediated through the down-regulation of miR-23a and subsequent up-regulation of MET protein expression, as confirmed by gain- and loss-of-function angiogenic experiments. In summary, our results demonstrated that ginsenoside-Rg{sub 1} could induce angiogenesis by the inverse regulation of MET tyrosine kinase receptor expression through miR-23a. This study has broadened our understanding of the non-genomic effects of ginsenoside-Rg{sub 1,} and provided molecular evidence that warrant further development of natural compound as novel angiogenesis-promoting therapy. - Highlights: • Therapeutic angiogenesis has been implicated in ischemic diseases and wound healing. • Ginsenoside-Rg{sub 1} (Rg{sub 1}) has been demonstrated as an angiogenesis-stimulating compound. • We found that Rg{sub 1} induces angiogenesis by

  12. Effect of dioxins on regulation of tyrosine hydroxylase gene expression by aryl hydrocarbon receptor: a neurotoxicology study

    Directory of Open Access Journals (Sweden)

    Akahoshi Eiichi

    2009-06-01

    Full Text Available Abstract Background Dioxins and related compounds are suspected of causing neurological disruption. Epidemiological studies indicated that exposure to these compounds caused neurodevelopmental disturbances such as learning disability and attention deficit hyperactivity disorder, which are thought to be closely related to dopaminergic dysfunction. Although the molecular mechanism of their actions has not been fully investigated, a major participant in the process is aryl hydrocarbon receptor (AhR. This study focused on the effect of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD exposure on the regulation of TH, a rate-limiting enzyme of dopamine synthesis, gene expression by AhR. Methods N2a-Rβ cells were established by transfecting murine neuroblastoma Neuro2a with the rat AhR cDNA. TH expression induced by TCDD was assessed by RT-PCR and Western blotting. Participation of AhR in TCDD-induced TH gene expression was confirmed by suppressing AhR expression using the siRNA method. Catecholamines including dopamine were measured by high-performance liquid chromatography. A reporter gene assay was used to identify regulatory motifs in the promoter region of TH gene. Binding of AhR with the regulatory motif was confirmed by an electrophoretic mobility shift assay (EMSA. Results Induction of TH by TCDD through AhR activation was detected at mRNA and protein levels. Induced TH protein was functional and its expression increased dopamine synthesis. The reporter gene assay and EMSA indicated that AhR directly regulated TH gene expression. Regulatory sequence called aryl hydrocarbon receptor responsive element III (AHRE-III was identified upstream of the TH gene from -285 bp to -167 bp. Under TCDD exposure, an AhR complex was bound to AHRE-III as well as the xenobiotic response element (XRE, though AHRE-III was not identical to XRE, the conventional AhR-binding motif. Conclusion Our results suggest TCDD directly regulate the dopamine system by TH gene

  13. The hepatocyte growth factor (HGF)-MET receptor tyrosine kinase signaling pathway: Diverse roles in modulating immune cell functions.

    Science.gov (United States)

    Ilangumaran, Subburaj; Villalobos-Hernandez, Alberto; Bobbala, Diwakar; Ramanathan, Sheela

    2016-06-01

    Hepatocyte growth factor (HGF) signaling via the MET receptor is essential for embryonic development and tissue repair. On the other hand, deregulated MET signaling promotes tumor progression in diverse types of cancers. Even though oncogenic MET signaling remains the major research focus, the HGF-MET axis has also been implicated in diverse aspects of immune cell development and functions. In the presence of other hematopoietic growth factors, HGF promotes the development of erythroid, myeloid and lymphoid lineage cells and thrombocytes. In monocytes and macrophages responding to inflammatory stimuli, induction of autocrine HGF-MET signaling can contribute to tissue repair via stimulating anti-inflammatory cytokine production. HGF-MET signaling can also modulate adaptive immune response by facilitating the migration of Langerhans cells and dendritic cells to draining lymph nodes. However, MET signaling has also been shown to induce tolerogenic dendritic cells in mouse models of graft-versus-host disease and experimental autoimmune encephalomyelitis. HGF-MET axis is also implicated in promoting thymopoiesis and the survival and migration of B lymphocytes. Recent studies have shown that MET signaling induces cardiotropism in activated T lymphocytes. Further understanding of the HGF-MET axis in the immune system would allow its therapeutic manipulation to improve immune cell reconstitution, restore immune homeostasis and to treat immuno-inflammatory diseases. PMID:26822708

  14. Molecular mechanisms of the synergy between cysteinyl-leukotrienes and receptor tyrosine kinase growth factors on human bronchial fibroblast proliferation

    Directory of Open Access Journals (Sweden)

    Hajime Yoshisue

    2006-12-01

    Full Text Available We have reported that cysteinyl-leukotrienes (cys-LTs synergise not only with epidermal growth factor (EGF but also with platelet-derived growth factor (PDGF and fibroblast growth factor (FGF to induce mitogenesis in human bronchial fibroblasts. We now describe the molecular mechanisms underlying this synergism. Mitogenesis was assessed by incorporation of [3H]thymidine into DNA and changes in protein phosphorylation by Western blotting. Surprisingly, no CysLT receptor antagonists (MK-571, montelukast, BAY u9773 prevented the synergistic mitogenesis. LTD4 did not cause phosphorylation of EGFR nor did it augment EGF-induced phosphorylation of EGFR, and the synergy between LTD4 and EGF was not blocked by the metalloproteinase inhibitor GM6001 or by an HB-EGF neutralising antibody. The EGFR-selective kinase inhibitor, AG1478, suppressed the synergy by LTD4 and EGF, but had no effect on the synergy with PDGF and FGF. While inhibitors of mitogen-activated protein kinase, phosphatidylinositol 3-kinase and protein kinase C (PKC prevented the synergy, these drugs also inhibited mitogenesis elicited by EGF alone. In contrast, pertussis toxin (PTX efficiently inhibited the potentiating effect of LTD4 on EGF-induced mitogenesis, as well as that provoked by PDGF or FGF, but had no effect on mitogenesis elicited by the growth factors alone. Whereas LTD4 alone did not augment phosphorylation of extracellular signal-regulated kinase (Erk-1/2 and Akt, it increased phosphorylation of PKC in a Gi-dependent manner. Addition of LTD4 prolonged the duration of EGF-induced phosphorylation of Erk-1/2 and Akt, both of which were sensitive to PTX. The effect of cys-LTs involves a PTX-sensitive and PKC-mediated intracellular pathway leading to sustained growth factor-dependent phosphorylation of Erk-1/2 and Akt.

  15. Antitumor activity of F90,an epidermal growth factor receptor tyrosine kinase inhibitor,on glioblastoma cell line SHG-44

    Institute of Scientific and Technical Information of China (English)

    LIU Fang-jun; GUI Song-bai; LI Chu-zhong; SUN Ze-lin; ZHANG Ya-zhuo

    2008-01-01

    Background Over-expression of epidermal growth factor receptor (EGFR) is thought to be related to cell proliferation,invasion,metastasis,resistance to chemoradiotherapy and poor prognosis of various human cancers.Forty percent to fifty percent of glioblastoma multiforme (GBM) possess deregulated EGFR,which may contribute to the aggressive and refractory course of GBM.Therefore,blockade of EGFR signal transduction may be a promising treatment strategy for GBM.Methods MIT assay,cell growth curve assay and tumor xenograft model were used to evaluate the antitumor activity of F90 against SHG-44 in vitro and in vivo.Western blot assay was applied to evaluate the expression of p-EGFR,p-ERK1,p-JNK,p-P38,Bcl2 and P53 proteins.Results F90 inhibited the cell proliferation in a dose-dependent manner in vitro.The growth of SHG-44 tumor xenografts was suppressed by F90 at a high dose level (100 mg.kg-1.d-1).Phosphorylation of EGFR and activated downstream signaling proteins,such as ERK1,JNK and P38,were found to be depressed after incubation with F90 for 48 hours in vitro.Down-regulated Bcl2 protein and up-regulated P53 protein were also observed.Conclueions The results demonstrate that F90 is effective in inhibiting the proliferation of SHG-44 cells in vitro and tumor growth in vivo,suggesting that F90 may be a new therapeutic option for treatment of GBM.

  16. Ribosomal Protein S6 Kinase (RSK-2 as a central effector molecule in RON receptor tyrosine kinase mediated epithelial to mesenchymal transition induced by macrophage-stimulating protein

    Directory of Open Access Journals (Sweden)

    Zhang Rui-Wen

    2011-05-01

    Full Text Available Abstract Background Epithelial to mesenchymal transition (EMT occurs during cancer cell invasion and malignant metastasis. Features of EMT include spindle-like cell morphology, loss of epithelial cellular markers and gain of mesenchymal phenotype. Activation of the RON receptor tyrosine kinase by macrophage-stimulating protein (MSP has been implicated in cellular EMT program; however, the major signaling determinant(s responsible for MSP-induced EMT is unknown. Results The study presented here demonstrates that RSK2, a downstream signaling protein of the Ras-Erk1/2 pathway, is the principal molecule that links MSP-activated RON signaling to complete EMT. Using MDCK cells expressing RON as a model, a spindle-shape based screen was conducted, which identifies RSK2 among various intracellular proteins as a potential signaling molecule responsible for MSP-induced EMT. MSP stimulation dissociated RSK2 with Erk1/2 and promoted RSK2 nuclear translocation. MSP strongly induced RSK2 phosphorylation in a dose-dependent manner. These effects relied on RON and Erk1/2 phosphorylation, which is significantly potentiated by transforming growth factor (TGF-β1, an EMT-inducing cytokine. Specific RSK inhibitor SL0101 completely prevented MSP-induced RSK phosphorylation, which results in inhibition of MSP-induced spindle-like morphology and suppression of cell migration associated with EMT. In HT-29 cancer cells that barely express RSK2, forced RSK2 expression results in EMT-like phenotype upon MSP stimulation. Moreover, specific siRNA-mediated silencing of RSK2 but not RSK1 in L3.6pl pancreatic cancer cells significantly inhibited MSP-induced EMT-like phenotype and cell migration. Conclusions MSP-induced RSK2 activation is a critical determinant linking RON signaling to cellular EMT program. Inhibition of RSK2 activity may provide a therapeutic opportunity for blocking RON-mediated cancer cell migration and subsequent invasion.

  17. Factors associated with early progression of non-small-cell lung cancer treated by epidermal growth factor receptor tyrosine-kinase inhibitors

    International Nuclear Information System (INIS)

    Epidermal growth factor receptor tyrosine-kinase inhibitors (EGFR-TKI) are a therapeutic option as second-line therapy in non-small-cell lung carcinoma (NSCLC), regardless of the EGFR gene status. Identifying patients with early progression during EGFR-TKI treatment will help clinicians to choose the best regimen, TKI or chemotherapy. From a prospective database, all patients treated with gefitinib or erlotinib between 2001 and 2010 were retrospectively reviewed. Patients were classified into two groups according to their tumor response by RECIST after 45 days of treatment, progressive disease (PD) or controlled disease (CD). Two hundred and sixty-eight patients were treated with EGFR-TKI, among whom 239 were classified as PD (n = 75) and CD (n = 164). Median overall survival was 77 days (95% CI 61–109) for PD and 385 days (95% CI 267–481) for CD. Patients with PD were of younger age (P = 0.004) and more frequently current smokers (P = 0.001) had more frequently a performance status ≥2 (P = 0.012), a weight loss ≥10% (P = 0.025), a shorter time since diagnosis (P < 0.0001), a pathological classification as non-otherwise-specified NSCLC (P = 0.01), and the presence of abdominal metastases (P = 0.008). In multivariate analysis, abdominal metastases were the only factor associated with early progression (odds ratio (OR) 2.17, 95% CI [1.12–4.19]; P = 0.021). Wild-type EGFR versus mutated EGFR was associated with early progression. The presence of abdominal metastasis was independently associated with early progression in metastatic NSCLC receiving EGFR-TKI

  18. Inhibiting receptor tyrosine kinase AXL with small molecule inhibitor BMS-777607 reduces glioblastoma growth, migration, and invasion in vitro and in vivo

    Science.gov (United States)

    Onken, Julia; Torka, Robert; Korsing, Sören; Radke, Josefine; Krementeskaia, Irina; Nieminen, Melina; Bai, Xi; Ullrich, Axel; Heppner, Frank; Vajkoczy, Peter

    2016-01-01

    Purpose Receptor tyrosine kinase AXL (RTK-AXL) is regarded as suitable target in glioma therapy. Here we evaluate the anti-tumoral effect of small molecule inhibitor BMS-777607 targeting RTK-AXL in a preclinical glioma model and provide evidence that RTK-AXL is expressed and phosphorylated in primary and recurrent glioblastoma multiforme (GBM). Experimental design We studied the impact of BMS-777607 targeting RTK-AXL in GBM models in vitro and in vivo utilizing glioma cells SF126 and U118MG. Impact on proliferation, apoptosis and angiogenesis was investigated by immunohistochemistry (IHC) and functional assays in vitro and in vivo. Tumor growth was assessed with MRI. Human GBM tissue was analyzed in terms of RTK-AXL phosphorylation by immunoprecipitation and immunohistochemistry. Results BMS-777607 displayed various anti-cancer effects dependent on increased apoptosis, decreased proliferation and migration in vitro and ex vivo in SF126 and U118 GBM cells. In vivo we observed a 56% tumor volume reduction in SF126 xenografts and remission in U118MG xenografts of more than 91%. The tube formation assay confirmed the anti-angiogenic effect of BMS-777607, which became also apparent in tumor xenografts. IHC of human GBM tissue localized phosphorylated RTK-AXL in hypercellular tumor regions, the migratory front of tumor cells in pseudo-palisades, and in vascular proliferates within the tumor. We further proved RTK-AXL phosphorylation in primary and recurrent disease state. Conclusion Collectively, these data strongly suggest that targeting RTK-AXL with BMS-777607 could represent a novel and potent regimen for the treatment of primary and recurrent GBM. PMID:26848524

  19. Prospective Study of Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors Concurrent With Individualized Radiotherapy for Patients With Locally Advanced or Metastatic Non-Small-Cell Lung Cancer

    International Nuclear Information System (INIS)

    Purpose: To establish the safety profile and efficacy of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) concurrent with individualized radiotherapy (RT) in patients with locally advanced or metastatic non-small-cell lung cancer (NSCLC). Patients and Methods: Between June 2007 and January 2010, 26 patients with Stage III/IV NSCLC were enrolled in this prospective study. These patients were treated with EGFR-TKIs (gefitinib 250 mg or erlotinib 150 mg, oral daily) concurrent with individualized RT with curative intent. The thoracic RT plans were individually designed on the basis of tumor size and normal tissue volume constraints. All patients were assessed for toxicity, and 25 patients were available for efficacy. The primary endpoints were acute toxicity, overall survival, and median survival time. The secondary endpoints included local control rate, time to tumor progression, and progression-free survival (PFS). Results: Median gross tumor volume, mean lung dose, and lung V20 were 56 cm3, 8.6 Gy, and 14%, respectively. Median thoracic radiation dose was 70 Gy at a margin of gross tumor volume (range, 42-82 Gy), and median biological equivalent dose was 105 Gy (range, 60-119 Gy). Acute skin, hematologic, esophageal, and pulmonary toxicities were acceptable and manageable. Severe adverse events included neutropenia (Grade 4, 4%) and thrombocytopenia (Grade 4, 8%), esophagitis (Grade 3, 4%), and pneumonitis (Grade 3, 4%). With a median follow-up of 10.2 months, a local control rate of 96% was achieved for thoracic tumor. Median time to progression, median PFS, and median survival time were 6.3, 10.2, and 21.8 months, respectively. The 1- and 2-year PFS rates were both 42%, and 1-, 2-, and 3-year overall survival rates were 57%, 45%, and 30%, respectively. Conclusion: Concurrent EGFR-TKIs with individualized RT shows a favorable safety profile and promising outcome, therefore serving as a therapeutic option for patients with locally advanced or

  20. Loss of the receptor tyrosine kinase Axl leads to enhanced inflammation in the CNS and delayed removal of myelin debris during Experimental Autoimmune Encephalomyelitis

    Directory of Open Access Journals (Sweden)

    Prieto Anne L

    2011-05-01

    Full Text Available Abstract Background Axl, together with Tyro3 and Mer, constitute the TAM family of receptor tyrosine kinases. In the nervous system, Axl and its ligand Growth-arrest-specific protein 6 (Gas6 are expressed on multiple cell types. Axl functions in dampening the immune response, regulating cytokine secretion, clearing apoptotic cells and debris, and maintaining cell survival. Axl is upregulated in various disease states, such as in the cuprizone toxicity-induced model of demyelination and in multiple sclerosis (MS lesions, suggesting that it plays a role in disease pathogenesis. To test for this, we studied the susceptibility of Axl-/- mice to experimental autoimmune encephalomyelitis (EAE, an animal model for multiple sclerosis. Methods WT and Axl-/- mice were immunized with myelin oligodendrocyte glycoprotein (MOG35-55 peptide emulsified in complete Freund's adjuvant and injected with pertussis toxin on day 0 and day 2. Mice were monitored daily for clinical signs of disease and analyzed for pathology during the acute phase of disease. Immunological responses were monitored by flow cytometry, cytokine analysis and proliferation assays. Results Axl-/- mice had a significantly more severe acute phase of EAE than WT mice. Axl-/- mice had more spinal cord lesions with larger inflammatory cuffs, more demyelination, and more axonal damage than WT mice during EAE. Strikingly, lesions in Axl-/- mice had more intense Oil-Red-O staining indicative of inefficient clearance of myelin debris. Fewer activated microglia/macrophages (Iba1+ were found in and/or surrounding lesions in Axl-/- mice relative to WT mice. In contrast, no significant differences were noted in immune cell responses between naïve and sensitized animals. Conclusions These data show that Axl alleviates EAE disease progression and suggests that in EAE Axl functions in the recruitment of microglia/macrophages and in the clearance of debris following demyelination. In addition, these data

  1. Influence of ginsenoside on expression of brain-derived neurotrophic factor and receptor tyrosine kinase B in the medial septum of aged rats

    Institute of Scientific and Technical Information of China (English)

    Liang Zeng; Haihua Zhao; Yongli Lü; Wenbo Dai

    2008-01-01

    BACKGROUND: It has been shown that ginsenoside, the effective component of ginseng, can enhance expression of choline acetyl transferase, as well as brain-derived neurotrophic factor (BDNF) and its receptor tyrosine kinase B (TrkB), in cholinergic neurons of the basal forebrain.OBJECTIVE: To qualitatively and quantitatively verify the influence of ginsenoside on expression of BDNF and its receptor, TrkB, in the medial septum of aged rats, and to provide a molecular basis for clinical application.DESIGN, TIME AND SETTING: A contrast study, which was performed in the Department of Anatomy, China Medical University, and the Department of Anatomy, Shenyang Medical College between December 2005 and May 2007.MATERIALS: Thirty-five, healthy, female, Sprague Dawley rats were selected for this study. Ginsenoside (81% purity) was provided by Jilin Ji'an Wantai Chinese Medicine Factory; anti-BDNF antibody, anti-TrkB antibody, and their kits were provided by Wuhan Boster Company.METHODS: A total of 35 rats were divided into three groups: young (four months old), aging (26 months old), and ginsenoside. Rats in the ginsenoside group were administered ginsenoside (25mg/kg/d) between 17 months and 26 months.MAIN OUTCOME MEASURES: Immunohistochemistry and in situ hybridization were used to measure expression of BDNF and TrkB in the medial septum of aged rats, and the detected results were expressed as gray values.RESULTS: ①Qualitative detection: using microscopy, degenerative neurons were visible in the medial septum in the aging group. However, neuronal morphology in the ginsenoside group was similar to neurons in the young group.②Quantitative detection: the mean gray value of BDNF-positive and TrkB-positive products in the aging group were significantly higher than in the young group (t=3.346,4.169, P<0.01); however, the mean gray value in the ginsenoside group was significantly lower than in the aging group (t=2.432,2.651, P<0.01).CONCLUSION: Ginsenoside can increase

  2. Targeting the epidermal growth factor receptor in non-small cell lung cancer cells: the effect of combining RNA interference with tyrosine kinase inhibitors or cetuximab

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    Chen Gang

    2012-03-01

    Full Text Available Abstract Background The epidermal growth factor receptor (EGFR is a validated therapeutic target in non-small cell lung cancer (NSCLC. However, current single agent receptor targeting does not achieve a maximal therapeutic effect, and some mutations confer resistance to current available agents. In the current study we have examined, in different NSCLC cell lines, the combined effect of RNA interference targeting the EGFR mRNA, and inactivation of EGFR signaling using different receptor tyrosine kinase inhibitors (TKIs or a monoclonal antibody cetuximab. Methods NSCLC cells (cell lines HCC827, H292, H358, H1650, and H1975 were transfected with EGFR siRNA and/or treated with the TKIs gefitinib, erlotinib, and afatinib, and/or with the monoclonal antibody cetuximab. The reduction of EGFR mRNA expression was measured by real-time quantitative RT-PCR. The down-regulation of EGFR protein expression was measured by western blot, and the proliferation, viability, caspase3/7 activity, and apoptotic morphology were monitored by spectrophotometry, fluorimetry, and fluorescence microscopy. The combined effect of EGFR siRNA and different drugs was evaluated using a combination index. Results EGFR-specific siRNA strongly inhibited EGFR protein expression almost equally in all cell lines and inhibited cell growth and induced cell apoptosis in all NSCLC cell lines studied, albeit with a different magnitude. The effects on growth obtained with siRNA was strikingly different from the effects obtained with TKIs. The effects of siRNA probably correlate with the overall oncogenic significance of the receptor, which is only partly inhibited by the TKIs. The cells which showed weak response to TKIs, such as the H1975 cell line containing the T790M resistance mutation, were found to be responsive to siRNA knockdown of EGFR, as were cell lines with downstream TKI resistance mutations. The cell line HCC827, harboring an exon 19 deletion mutation, was more than 10-fold

  3. ZD6474, an inhibitor of vascular endothelial growth factor receptor tyrosine kinase, inhibits growth of experimental lung metastasis and production of malignant pleural effusions in a non-small cell lung cancer model.

    Science.gov (United States)

    Matsumori, Yuka; Yano, Seiji; Goto, Hisatsugu; Nakataki, Emiko; Wedge, Stephen R; Ryan, Anderson J; Sone, Saburo

    2006-01-01

    ZD6474 is a novel, orally active inhibitor of vascular endothelial growth factor receptor-2 (VEGFR-2) tyrosine kinase, with some additional activity against epidermal growth factor receptor (EGFR) tyrosine kinase. The purpose of this study was to determine the potential of ZD6474 in the control of established experimental lung metastasis and pleural effusions produced by human non-small cell lung cancer (NSCLC) cells. PC14PE6 (adenocarcinoma) and H226 (squamous cell carcinoma) cells express high levels of EGFR and only PC14PE6 cells overexpress VEGF. Neither ZD6474 nor the EGFR tyrosine kinase inhibitor gefitinib inhibit proliferation of PC14PE6 or H226 cells in vitro. Both PC14PE6 and H226 cells inoculated intravenously into nude mice induced multiple lung nodules after 5-7 weeks. In addition, PC14PE6 cells produced bloody pleural effusions. Daily oral treatment with ZD6474 did not reduce the number of lung nodules produced by PC14PE6 or H226 cells, but did reduce the lung weight and the size of lung nodules. ZD6474 also inhibited the production of pleural effusions by PC14PE6 cells. Histological analyses of lung lesions revealed that ZD6474 treatment inhibited activation of VEGFR-2 and reduced tumor vascularization and tumor cell proliferation. Therapeutic effects of ZD6474 were considered likely to be due to inhibition of VEGFR-2 tyrosine kinase because gefitinib was inactive in this model. These results indicate that ZD6474, an inhibitor of VEGFR-2, may be useful in controlling the growth of established lung metastasis and pleural effusions by NSCLC. PMID:16783964

  4. Microgravity and Signaling Molecules in Rat Osteoblasts: Downstream of Receptor Tyrosine Kinase, G-Protein-Coupled Receptor, and Small GTP-Binding Proteins

    Science.gov (United States)

    Kumel, Yasuhiro; Shimokawa, Hitoyata; Morita, Sadao; Katano, Hisako; Akiyama, Hideo; Hirano, Masahiko; Ohya, Keiichi; Sams, Clarence F.; Whitson, Peggy A.

    2005-01-01

    Rat osteoblasts were cultured for 4 and 5 days aboard Space Shuttle and solubilized on board. The mRNA levels of the post-receptor signaling molecules were analyzed by quantitative RT-PCR. The G-protein alpha subunit G(alpha)q mRNA levels were elevated 3-fold by microgravity. G(alpha)q stimulates PLC(beta), and then PKC. PKC(delta) and PKC(theta) mRNA levels were increased 2- to 5-fold by microgravity The mRNA levels of SOS and Ras GRF were increased 4 to 5-fold by microgravity, while Ras GAP was not altered. Spaceflight-induced bone loss might be attributed to microgravity modulation of the signaling pathway in osteoblasts.

  5. Affinity chromatography purification of angiotensin II reactor using photoactivable biotinylated probes

    Energy Technology Data Exchange (ETDEWEB)

    Marie, J.; Seyer, R.; Lombard, C.; Desarnaud, F.; Aumelas, A.; Jard, A.; Bonnafous, J.C. (Centre CNRS-INSERM de Pharmacologie-Endocrinologie, Montpellier (France))

    1990-09-25

    The authors have developed biotinylated photoactivable probes that are suitable for covalent labeling of angiotensin II (AII) receptors and the subsequent purification of covalent complexes through immobilized avidin or streptavidin. One of these probes, biotin-NH(CH{sub 2}){sub 2}SS(CH{sub 2}){sub 2}CO-(Ala{sup 1}, Phe(4N{sub 3}){sup 8})AII, which contains a cleavage disulfide bridge in its spacer arm and which displays, in its radioiodinated form, very high affinity for AII receptors (K{sub d}{approximately}1 nM), proved to be suitable for indirect affinity chromatography of rate liver receptor with facilitated recovery from avidin gels by use of reducing agents. This constituted the central step of an efficient partial purification scheme involving hydroxylapatite chromatography, streptavidin chromatography, and thiopropyl-Sepharose chromatography. SDS-PAGE analysis and autoradiography established the identity of the purified entity (molecular weight 65K) as the AII receptor. Possible ways of completing purification to homogeneity and extrapolation of the protocols to a preparative scale are discussed, as well as the potential contribution of our new probes to the study of the structural properties of angiotensin receptors.

  6. Affinity chromatography purification of angiotensin II reactor using photoactivable biotinylated probes

    International Nuclear Information System (INIS)

    The authors have developed biotinylated photoactivable probes that are suitable for covalent labeling of angiotensin II (AII) receptors and the subsequent purification of covalent complexes through immobilized avidin or streptavidin. One of these probes, biotin-NH(CH2)2SS(CH2)2CO-[Ala1, Phe(4N3)8]AII, which contains a cleavage disulfide bridge in its spacer arm and which displays, in its radioiodinated form, very high affinity for AII receptors (Kd∼1 nM), proved to be suitable for indirect affinity chromatography of rate liver receptor with facilitated recovery from avidin gels by use of reducing agents. This constituted the central step of an efficient partial purification scheme involving hydroxylapatite chromatography, streptavidin chromatography, and thiopropyl-Sepharose chromatography. SDS-PAGE analysis and autoradiography established the identity of the purified entity (molecular weight 65K) as the AII receptor. Possible ways of completing purification to homogeneity and extrapolation of the protocols to a preparative scale are discussed, as well as the potential contribution of our new probes to the study of the structural properties of angiotensin receptors

  7. A novel biotinylated surface designed for QCM-D applications

    OpenAIRE

    Nilebäck, Erik

    2009-01-01

      Control of protein immobilization at sensor surfaces is of great interest within various scientific fields, since it enables studies of specific biomolecular interactions. To achieve this, one must be able to immobilize proteins with retained native structure, while minimizing non-specific protein binding. The high affinity interaction between streptavidin (SA) and biotin is extensively used as a linker between a surface, where SA is immobilized, and the (biotinylated) molecule of interest....

  8. Receptor tyrosine kinase-like orphan receptor 1, a target of NKX2-1/TTF-1 lineage-survival oncogene, inhibits apoptosis signal-regulating kinase 1-mediated pro-apoptotic signaling in lung adenocarcinoma.

    Science.gov (United States)

    Ida, Lisa; Yamaguchi, Tomoya; Yanagisawa, Kiyoshi; Kajino, Taisuke; Shimada, Yukako; Suzuki, Motoshi; Takahashi, Takashi

    2016-02-01

    We previously identified receptor tyrosine kinase-like orphan receptor 1 (ROR1) as a transcriptional target of the NKX2-1/TTF-1 lineage-survival oncogene in lung adenocarcinoma. ROR1 consequently sustains a favorable balance between pro-survival phosphatidylinositol 3-kinase-protein kinase B and pro-apoptotic apoptosis signal-regulating kinase 1 (ASK1)-p38MAPK signaling. In contrast to recent advances in understanding how ROR1 sustains pro-survival signaling, the mechanism of ROR1 repression of pro-apoptotic signaling remains rather elusive. In the present study, we investigated the underlying mechanism of ROR1-mediated inhibition of the ASK1-p38MAPK signaling pathway. Growth inhibition mediated by siROR1 was partially but significantly alleviated by ASK1 co-knockdown in lung adenocarcinoma cell lines. Also, ASK1 phosphorylation at Thr845, which reflects its activated state, was clearly inhibited by ROR1 overexpression in both steady state and oxidative stress-elicited conditions in MSTO-211H cells. In addition, we found that ROR1 was physically associated with ASK1 at the C-terminal serine threonine-rich domain of ROR1. Furthermore, ROR1 kinase activity was shown to be required to repress the ASK1-p38 axis and oxidative stress-induced cell death. The present findings thus support our notion that ROR1 sustains lung adenocarcinoma survival, at least in part, through direct physical interaction with ASK1 and consequential repression of the pro-apoptotic ASK1-p38 axis in a ROR1 kinase activity-dependent manner. PMID:26661061

  9. Antacid Use and De Novo Brain Metastases in Patients with Epidermal Growth Factor Receptor-Mutant Non-Small Cell Lung Cancer Who Were Treated Using First-Line First-Generation Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors.

    Directory of Open Access Journals (Sweden)

    Yu-Mu Chen

    Full Text Available Antacid treatments decrease the serum concentrations of first-generation epidermal growth factor receptor (EGFR-tyrosine kinase inhibitors (TKIs, although it is unknown whether antacids affect clinical outcomes. As cerebrospinal fluid concentrations of TKIs are much lower than serum concentrations, we hypothesized that this drug-drug interaction might affect the prognosis of patients with de novo brain metastases.This retrospective study evaluated 269 patients with EGFR-mutant non-small cell lung cancer (NSCLC who had been diagnosed between December 2010 and December 2013, and had been treated using first-line first-generation EGFR-TKIs. Among these patients, we identified patients who concurrently used H2 receptor antagonists (H2RAs and proton pump inhibitors (PPIs as antacids. Patients who exhibited >30% overlap between the use of TKIs and antacids were considered antacid users.Fifty-seven patients (57/269, 21.2% were antacid users, and antacid use did not significantly affect progression-free survival (PFS; no antacids: 11.2 months, H2RAs: 9.4 months, PPIs: 6.7 months; p = 0.234. However, antacid use significantly reduced overall survival (OS; no antacids: 25.0 months, H2RAs: 15.5 months, PPIs: 11.3 months; p = 0.002. Antacid use did not affect PFS for various metastasis sites, although antacid users with de novo brain metastases exhibited significantly shorter OS, compared to non-users (11.8 vs. 16.3 months, respectively; p = 0.041. Antacid use did not significantly affect OS in patients with bone, liver, or pleural metastases.Antacid use reduced OS among patients with EGFR-mutant NSCLC who were treated using first-line first-generation EGFR-TKIs, and especially among patients with de novo brain metastases.

  10. Down-regulation of estrogen receptor-alpha and rearranged during transfection tyrosine kinase is associated with withaferin a-induced apoptosis in MCF-7 breast cancer cells

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    Samadi Abbas K

    2011-10-01

    Full Text Available Abstract Background Withaferin A (WA, a naturally occurring withanolide, induces apoptosis in both estrogen-responsive MCF-7 and estrogen-independent MDA-MB-231 breast cancer cell lines with higher sensitivity in MCF-7 cells, but the underlying mechanisms are not well defined. The purpose of this study was to determine the anti-cancer effects of WA in MCF-7 breast cancer cells and explore alterations in estrogen receptor alpha (ERα and its associated molecules in vitro as novel mechanisms of WA action. Methods The effects of WA on MCF-7 viability and proliferation were evaluated by 3-(4, 5-dimethylthiazol-2-yl-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl-2H-tetrazolium (MTS assay and trypan blue exclusion assays. Apoptosis was evaluated by Annexin V-fluorescein isothiocyanate (FITC/propidium iodide (PI flow cytometry and Western blot analysis of poly (ADP-ribose polymerase (PARP cleavage. Cell cycle effects were analyzed by PI flow cytometry. Western blotting was also conducted to examine alterations in the expression of ERα and pathways that are associated with ERα function. Results WA resulted in growth inhibition and decreased viability in MCF-7 cells with an IC50 of 576 nM for 72 h. It also caused a dose- and time-dependent apoptosis and G2/M cell cycle arrest. WA-induced apoptosis was associated with down-regulation of ERα, REarranged during Transfection (RET tyrosine kinase, and heat shock factor-1 (HSF1, as well as up-regulation of phosphorylated p38 mitogen-activated protein kinase (phospho-p38 MAPK, p53 and p21 protein expression. Co-treatment with protein synthesis inhibitor cycloheximide or proteasome inhibitor MG132 revealed that depletion of ERα by WA is post-translational, due to proteasome-dependent ERα degradation. Conclusions Taken together, down-regulation of ERα, RET, HSF1 and up-regulation of phospho-p38 MAPK, p53, p21 are involved in the pro-apoptotic and growth-inhibitory effects of WA in MCF-7 breast cancer cells in

  11. Role of PAX8 in the regulation of MET and RON receptor tyrosine kinases in non-small cell lung cancer

    International Nuclear Information System (INIS)

    Non-small cell lung cancers (NSCLC) are highly heterogeneous at the molecular level and comprise 75% of all lung tumors. We have previously shown that the receptor tyrosine kinase (RTK) MET frequently suffers gain-of-function mutations that significantly promote lung tumorigenesis. Subsequent studies from our lab also revealed that PAX5 transcription factor is preferentially expressed in small cell lung cancer (SCLC) and promotes MET transcription. PAX8, however, is also expressed in NSCLC cell lines. We therefore investigated the role of PAX8 in NSCLC. Using IHC analysis, PAX8 protein expression was determined in archival NSCLC tumor tissues (n = 254). In order to study the effects of PAX8 knockdown on NSCLC cellular functions such as apoptosis and motility, siRNA against PAX8 was used. Confocal fluorescence microscopy was used to monitor the localization of MET, RON and PAX8. The combinatorial effect of PAX8 knockdown and MET inhibition using SU11274 was investigated in NSCLC cell viability assay. Relative levels of PAX8 protein were elevated (≥ + 2 on a scale of 0–3) in adenocarcinoma (58/94), large cell carcinoma (50/85), squamous cell carcinoma (28/47), and metastatic NSCLC (17/28; lymph node). Utilizing early progenitors isolated from NSCLC cell lines and fresh tumor tissues, we observed robust overexpression of PAX8, MET, and RON. PAX8 knockdown A549 cells revealed abrogated PAX8 expression with a concomitant loss in MET and the related RON kinase expression. A dramatic colocalization between the active form of MET (also RON) and PAX8 upon challenging A549 cells with HGF was visualized. A similar colocalization of MET and EGL5 (PAX8 ortholog) proteins was found in embryos of C. elegans. Most importantly, knockdown of PAX8 in A549 cells resulted in enhanced apoptosis (~6 fold) and decreased cell motility (~45%), thereby making PAX8 a potential therapeutic target. However, the combinatorial approach of PAX8 knockdown and treatment with MET inhibitor, SU

  12. Involvement of transcription factor encoded by the mi locus in the expression of c-kit receptor tyrosine kinase in cultured mast cells of mice.

    Science.gov (United States)

    Tsujimura, T; Morii, E; Nozaki, M; Hashimoto, K; Moriyama, Y; Takebayashi, K; Kondo, T; Kanakura, Y; Kitamura, Y

    1996-08-15

    The mi locus of mice encodes a member of the basic-helix-loop-helix-leucine zipper (bHLH-Zip) protein family of transcription factors (hereafter called MITF). Cultured mast cells of mi/mi genotype (mi/mi CMCs) did not normally respond to stem cell factor (SCF), a ligand for the c-kit receptor tyrosine kinase. The poor response of mi/mi CMCs to SCF was attributed to the deficient expression of c-kit both the mRNA and protein levels. The purpose of the present study is to investigate the effect of MITF on the transcription of the c-kit gene. First, we introduced cDNA encoding normal (+) MITF or mutant (mi) MITF into mi/mi CMCs using the retroviral vector. Overexpression of (+)-MITF but not mi-MITF normalized the expression of the c-kit and the poor response of mi/mi CMCs to SCF, indicating the involvement of (+)-MITF in the c-kit gene transactivation. Second, we analyzed the promoter of the c-kit gene. Three CANNTG motifs recognized by bHLH-Zip-type transcription factors were conserved between the mouse and human c-kit promoters. Among these three CANNTG motifs, only the CACCTG motif (nt -356 to -351) was specifically bound by (+)-MITF. When the luciferase gene under the control of the c-kit promoter was contransfected into NIH/3T3 fibroblasts with cDNA encoding (+)-MITF or mi-MITF, the luciferase activity significantly increased only when (+)-MITF cDNA was cotransfected. The deletion of the promoter region containing the CACCTG motif or the mutation of the CACCTG to CTCCAG abolished the transactivation effect of (+)-MITF, indicating that (+)-MITF transactivated the c-kit gene through the CACCTG motif. When the luciferase gene under the control of the c-kit promoter was introduced into the FMA3 mastocytoma and FEC-P1 myeloid cell lines, remarkable luciferase activity was observed only in FMA3 cells. Thus, the involvement of (+)-MITF in the c-kit transactivation appeared to be specific to the mast cell lineage. PMID:8695840

  13. Non-small-cell lung cancer cells combat epidermal growth factor receptor tyrosine kinase inhibition through immediate adhesion-related responses

    Directory of Open Access Journals (Sweden)

    Wang HY

    2016-05-01

    Full Text Available Hsian-Yu Wang,1,2 Min-Kung Hsu,3,4 Kai-Hsuan Wang,1 Ching-Ping Tseng,2,4 Feng-Chi Chen,3,4 John T-A Hsu1,4 1Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes (NHRI, Zhunan, Miaoli County, 2Institute of Molecular Medicine and Bioengineering, National Chiao Tung University (NCTU, Hsinchu, 3Division of Biostatistics and Bioinformatics, Institute of Population Health Sciences, National Health Research Institutes (NHRI, Zhunan, Miaoli County, 4Department of Biological Science and Technology, National Chiao Tung University (NCTU, Hsinchu, Taiwan, Republic of China Background: Epidermal growth factor receptor (EGFR tyrosine kinase inhibitors (TKIs, such as gefitinib, erlotinib, and afatinib, have greatly improved treatment efficacy in non-small cell lung cancer (NSCLC patients with drug-sensitive EGFR mutations. However, in some TKI responders, the benefits of such targeted therapies are limited by the rapid development of resistance, and strategies to overcome this resistance are urgently needed. Studies of drug resistance in cancer cells typically involve long term in vitro induction to obtain stably acquired drug-resistant cells followed by elucidation of resistance mechanisms, but the immediate responses of cancer cells upon drug treatment have been ignored. The aim of this study was to investigate the immediate responses of NSCLC cells upon treatment with EGFR TKIs.Results: Both NSCLC cells, ie, PC9 and H1975, showed immediate enhanced adhesion-related responses as an apoptosis-countering mechanism upon first-time TKI treatment. By gene expression and pathway analysis, adhesion-related pathways were enriched in gefitinib-treated PC9 cells. Pathway inhibition by small-hairpin RNAs or small-molecule drugs revealed that within hours of EGFR TKI treatment, NSCLC cells used adhesion-related responses to combat the drugs. Importantly, we show here that the Src family inhibitor, dasatinib, dramatically inhibits

  14. Chemoprevention of 7, 12-dimethylbenz[a]anthracene (DMBA)-induced oral carcinogenesis in hamster cheek pouch by topical application of a dual inhibitor of epidermal growth factor receptor (EGFR) and ErbB2 tyrosine kinases

    OpenAIRE

    Sun, Zheng; Sood, Sandeep; Li, Ning; Yang, Peiying; Newman, Robert A.; Yang, Chung S.; Chen, Xiaoxin

    2007-01-01

    Oral cancer is a common neoplasm worldwide with tobacco and alcohol being the major etiological factors contributing to its pathogenesis. Epidermal growth factor receptor (EGFR) and ErbB2 are known to be involved in the development of oral cancer with the former up-regulated in up to 90% human cases. The goal of this study was to evaluate the chemopreventive effects of a dual inhibitor of EGFR and ErbB2 tyrosine kinases, GW2974, in the 7, 12-dimethylbenz[a]anthracene (DMBA)-induced hamster ch...

  15. Angiotensin II-Induced Migration of Vascular Smooth Muscle Cells Is Mediated by p38 Mitogen-Activated Protein Kinase-Activated c-Src Through Spleen Tyrosine Kinase and Epidermal Growth Factor Receptor Transactivation

    OpenAIRE

    Mugabe, Benon E.; Yaghini, Fariborz A.; Song, Chi Young; Buharalioglu, Cuneyt K.; Waters, Christopher M.; Malik, Kafait U.

    2010-01-01

    Angiotensin II (Ang II) stimulates protein synthesis by activating spleen tyrosine kinase (Syk) and DNA synthesis through epidermal growth factor receptor (EGFR) transactivation in vascular smooth muscle cells (VSMCs). This study was conducted to determine whether Syk mediates Ang II-induced migration of aortic VSMCs using a scratch wound approach. Treatment with Ang II (200 nM) for 24 h increased VSMC migration by 1.56 ± 0.14-fold. Ang II-induced VSMC migration and Syk phosphorylation as det...

  16. SU11274衍生物的合成及受体酪氨酸激酶抑制活性评价%Synthesis and Biochemical Evaluation of Receptor Tyrosine Kinase Inhibitory Activity of SUl1274 Analogs

    Institute of Scientific and Technical Information of China (English)

    徐培培; 颜海燕; 张首国; 刘靖; 温晓雪; 彭涛; 徐琪寿; 王林

    2011-01-01

    目的 合成SU11274衍生物并对其进行受体PTK抑制活性评价.方法 合成了用乙二胺、1,3-丙二胺、1,2-丙二胺、1,6-己二胺替代SU11274哌嗪基团的4个SU11274新衍生物,结构经1H-NMR和ESI-MS验证.采用ELISA方法对这4个化合物进行了受体PTK抑制活性评价.结果 合成的4个SU11274衍生物(5a,5b,5c,5d)均为新化合物.生物学评价结果显示化合物5b的受体PTK抑制活性要显著优于SU11274,化合物5c有非常显著的受体PTK抑制活性,而5a和5d则较弱.结论 SU11274的哌嗪基团被不同二胺取代会影响化合物的受体PTK抑制活性.%Objective To synthesize and evaluate the inhibition of SUl1274 analogs on the receptor tyrosine kinase. Methods Four new SUI 1274 analogs with 1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminopropane and 1,6-diaminohexane substituting the SUl1274 piperazine group were synthesized. Their structur es were verified by 1H-NMR and ESI-MS. The receptor tyrosine kinase inhibitiory activity was studied by ELISA assay. Results Four SU11274 analogs were new compounds. Biochemicalevaluations demonstrate that receptor tyrosine kinase inhibitory activity of 5 b was significantly better than that of SU 11274, but that of compound 5 c was the most significant. The inhibitory activities of 5 a and 5 b was very low. Conclusion Substitution of the piperazine of SU 11274 with different side chains affects the inhibitory activity of receptor tyrosine kinase of SU11274 analogs.

  17. Phosphorylation of Tyrosine 1070 at the GluN2B Subunit Is Regulated by Synaptic Activity and Critical for Surface Expression of N-Methyl-D-aspartate (NMDA) Receptors.

    Science.gov (United States)

    Lu, Wen; Fang, Weiqing; Li, Jian; Zhang, Bin; Yang, Qian; Yan, Xunyi; Peng, Lin; Ai, Heng; Wang, Jie-jie; Liu, Xiao; Luo, Jianhong; Yang, Wei

    2015-09-18

    The number and subunit composition of synaptic N-methyl-d-aspartate receptors (NMDARs) play critical roles in synaptic plasticity, learning, and memory and are implicated in neurological disorders. Tyrosine phosphorylation provides a powerful means of regulating NMDAR function, but the underling mechanism remains elusive. In this study we identified a tyrosine site on the GluN2B subunit, Tyr-1070, which was phosphorylated by a proto-oncogene tyrosine-protein (Fyn) kinase and critical for the surface expression of GluN2B-containing NMDARs. The phosphorylation of GluN2B at Tyr-1070 was required for binding of Fyn kinase to GluN2B, which up-regulated the phosphorylation of GluN2B at Tyr-1472. Moreover, our results revealed that the phosphorylation change of GluN2B at Tyr-1070 accompanied the Tyr-1472 phosphorylation and Fyn associated with GluN2B in synaptic plasticity induced by both chemical and contextual fear learning. Taken together, our findings provide a new mechanism for regulating the surface expression of NMDARs with implications for synaptic plasticity. PMID:26229100

  18. Differential expression of dopamine D2 and D4 receptor and tyrosine hydroxylase mRNA in mice prone, or resistant, to chronic high-fat diet-induced obesity.

    Science.gov (United States)

    Huang, Xu-Feng; Yu, Yinghua; Zavitsanou, Katerina; Han, Mei; Storlien, Len

    2005-04-27

    The present study examined brain dopamine D2 and D4 receptor and tyrosine hydroxylase (TH) mRNA expression in chronic high-fat diet-induced obese (cDIO) and obese-resistant (cDR) mice. Twenty-eight mice were fed a high-fat diet (HF: 40% of calories from fat) for 6 weeks and then classified as cDIO (n = 8) or cDR (n = 8) mice according to the highest and lowest body weight gainers, respectively. Seven mice were fed a low-fat diet (LF: 10% of calories from fat) and used as controls. After 20 weeks of feeding, visceral fat per gram of initial body weight was significantly higher in the cDIO group (ratio: 0.25, 0.09, and 0.04; P cDIO vs. cDR and LF, respectively). Using quantitative in situ hybridization techniques, the levels of D2 and D4 receptor and tyrosine hydroxylase (TH) mRNAs were measured in multiple brain sections. The cDIO mice had a significantly higher level of D2 receptor mRNA expression in the core of the nucleus accumbens (AcbC, +16%) and ventral parts of caudate putamen (CPu, 21% and 24%) compared to the cDR and LF mice. The levels of D2 receptor mRNA expression in the AcbC and ventromedial part of the CPu were positively related to the final body weight. This study is the first to systematically examine the D4 mRNA expression in the mouse brain using in situ hybridization method. D4 receptor mRNA expression in the ventromedial hypothalamic nucleus (VMH) and the ventral part of the lateral septal nucleus were also significantly higher in the cDIO mice compared to the cDR and LF mice (+31% and +60%; P cDIO mice compared to cDR mice. In conclusion, this study has demonstrated differentially regulated levels of D2 and D4 receptor and TH mRNA expression in specific brain regions of cDIO and cDR mice. It provides evidence that D4 receptors may play an important role influencing satiety via the mesohypothalamic pathway while the D2 receptor may regulate reward and motor centers via mesolimbic and nigrostriatal pathways. These findings contribute to the

  19. Baseline and Trend of Lymphocyte-to-Monocyte Ratio as Prognostic Factors in Epidermal Growth Factor Receptor Mutant Non-Small Cell Lung Cancer Patients Treated with First-Line Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors.

    Directory of Open Access Journals (Sweden)

    Yu-Mu Chen

    Full Text Available Patients with early-stage lung cancer who have a high baseline lymphocyte-to-monocyte ratio (LMR have a favorable prognosis. However, the prognostic significance of LMR in patients with advanced-stage EGFR-mutant non-small cell lung cancer (NSCLC receiving first-line epidermal growth factor receptor (EGFR-tyrosine kinase inhibitors (TKIs has not been established. We conducted a retrospective analysis to investigate the influence of LMR on clinical outcomes including progression-free survival (PFS and overall survival (OS in EGFR-mutant patients with NSCLC.Of 1310 lung cancer patients diagnosed between January 2011 and October 2013, 253 patients receiving first-line EGFR-TKIs for EGFR-mutant NSCLC were included. The cut-off values for baseline and the 1-month-to-baseline ratio of LMR (MBR, determined by using receiver operating characteristic curves, were 3.29 and 0.63, respectively. Patients were divided into 3 prognostic groups: high LMR and MBR, high LMR or MBR, and low LMR and MBR.The mean patient age was 65.2 years, and 41% were men. The median PFS and OS were 10.3 and 22.0 months, respectively. The PFS in patients with high LMR and MBR, high LMR or MBR, and low LMR and MBR were 15.4, 7.1, and 2.0 months, respectively (p < 0.001, whereas the OS were 32.6, 13.7, and 5.1 months, respectively (p < 0.001.A combination of baseline and trend of LMR can be used to identify patients with a high mortality risk in EGFR-mutant NSCLC patients receiving first-line EGFR-TKIs.

  20. Higher Seizure Susceptibility and Enhanced Tyrosine Phosphorylation of N-Methyl-d-Aspartate Receptor Subunit 2B in fyn Transgenic Mice

    OpenAIRE

    Kojima, Nobuhiko; Ishibashi, Hidetoshi; Obata, Kunihiko; Kandel, Eric R.

    1998-01-01

    Earlier work has suggested that Fyn tyrosine kinase plays an important role in synaptic plasticity. To understand the downstream targets of Fyn signaling cascade in neurons, we generated transgenic mice expressing either a constitutively activated form of Fyn or native Fyn in neurons of the forebrain. Transgenic mice expressing mutant Fyn exhibited higher seizure activity and were prone to sudden death. Mice overexpressing native Fyn did not show such an obvious epileptic phenotype, but they ...

  1. Signaling by Tyrosine Kinases Negatively Regulates the Interaction between Transcription Factors and SMRT (Silencing Mediator of Retinoic Acid and Thyroid Hormone Receptor) Corepressor

    OpenAIRE

    Hong, Suk-Hyun; Wong, Chi-Wai; Privalsky, Martin L.

    1998-01-01

    Nuclear hormone receptors are hormone-regulated transcription factors that bind to specific sites on DNA and modulate the expression of adjacent target genes. Many nuclear hormone receptors display bimodal transcriptional properties; thyroid hormone receptors, for example, typically repress target gene expression in the absence of hormone, but activate target gene expression in the presence of hormone. The ability to repress is closely linked to the ability of the apo-receptor to physically b...

  2. Epidermal growth factor receptor tyrosine kinase regulates the human inward rectifier potassium K IR2.3 channel, stably expressed in HEK 293 cells

    OpenAIRE

    ZHANG, DE-YONG; Zhang, Yan-Hui; Sun, Hai-Ying; Lau, Chu-Pak; Li, Gui-Rong

    2011-01-01

    Background and Purpose The detailed molecular modulation of inward rectifier potassium channels (including the K IR2.3 channel) is not fully understood. The present study was designed to determine whether human K IR2.3 (K IR2.3) channels were regulated by protein tyrosine kinases (PTKs). Experimental Approach Whole-cell patch voltage-clamp, immunoprecipitation, Western blot analysis and site-directed mutagenesis were employed to determine the potential PTK phosphorylation of Kir2.3 current in...

  3. Monitoring of epidermal growth factor receptor tyrosine kinase inhibitor-sensitizing and resistance mutations in the plasma DNA of patients with advanced non-small cell lung cancer during treatment with erlotinib

    DEFF Research Database (Denmark)

    Sorensen, Boe S; Wu, Lin; Wei, Wen; Tsai, Julie; Weber, Britta; Nexo, Ebba; Meldgaard, Peter

    2014-01-01

    was tested in plasma DNA from patients with advanced NSCLC with allele-specific polymerase chain reaction assays. Blood samples from 23 patients with adenocarcinoma of NSCLC that carried tyrosine kinase inhibitor-sensitizing EGFR mutations were taken immediately before treatment with erlotinib......BACKGROUND: The feasibility of monitoring epidermal growth factor receptor (EGFR) mutations in plasma DNA from patients with advanced non-small cell lung cancer (NSCLC) during treatment with erlotinib and its relation to disease progression was investigated. METHODS: The amount of EGFR-mutant DNA....... Additional blood samples were taken at timed intervals until erlotinib treatment was withdrawn. RESULTS: The amount of plasma DNA with sensitizing EGFR mutations was found to be reduced after the first cycle of erlotinib treatment in 22 of 23 patients (96%). No patients presented with the resistant T790M...

  4. Determination of HER2 phosphorylation at tyrosine 1221/1222 improves prediction of poor survival for breast cancer patients with hormone receptor-positive tumors

    DEFF Research Database (Denmark)

    Frogne, Thomas; Laenkholm, Anne-Vibeke; Henriksen, Katrine Lütken;

    2009-01-01

    High expression of total HER2 protein confers poor prognosis for breast cancer patients. HER2 is a member of the HER family consisting of four receptors, HER1 to HER4. HER receptor activity is regulated by a variety of mechanisms, and phosphorylation of the C-terminal part of the HER receptors is a...... marker for active signaling. The importance of phosphorylation and thereby activation of the HER1 to HER4 receptors, however, has not been investigated concomitantly in breast tumors. In the present study we examined the importance of active HER signaling in breast tumor biopsies and paired metastases...

  5. Strategies for Overcoming Resistance to EGFR Family Tyrosine Kinase Inhibitors

    OpenAIRE

    Giaccone, Giuseppe; Wang, Yisong

    2011-01-01

    The first-generation epidermal growth factor receptor tyrosine kinase inhibitors erlotinib and gefitinib have been incorporated into treatment paradigms for patients with advanced non-small cell lung cancer. These agents are particularly effective in a subset of patients whose tumors harbor activating epidermal growth factor receptor mutations. However, most patients do not respond to these tyrosine kinase inhibitors, and those who do will eventually acquire resistance that typically results ...

  6. MP470, a novel receptor tyrosine kinase inhibitor, in combination with Erlotinib inhibits the HER family/PI3K/Akt pathway and tumor growth in prostate cancer

    International Nuclear Information System (INIS)

    Prostate cancer is a common disease in men and at present there is no effective therapy available due to its recurrence despite androgen deprivation therapy. The epidermal growth factor receptor family (EGFR/HER1, HER2/neu and HER3)/PI3K/Akt signaling axis has been implicated in prostate cancer development and progression. However, Erlotinib, an EGFR tyrosine kinase inhibitor, has less effect on proliferation and apoptosis in prostate cancer cell lines. In this study, we evaluate whether MP470, a novel receptor tyrosine kinase inhibitor alone or in combination with Erlotinib has inhibitory effect on prostate cancer in vitro and in vivo. The efficacy of MP470 or MP470 plus Erlotinib was evaluated in vitro using three prostate cancer cell lines by MTS and apoptosis assays. The molecular mechanism study was carried out by phosphorylation antibody array, immunoblotting and immunohistochemistry. A LNCaP mouse xenograft model was also used to determine the tumor growth inhibition by MP470, Erlotinib or the combination treatments. MP470 exhibits low μM IC50 in prostate cancer cell lines. Additive effects on both cytotoxicity and induction of apoptosis were observed when LNCaP were treated with MP470 in combination with Erlotinib. This combination treatment completely inhibited phosphorylation of the HER family members (HER1, 2, 3), binding of PI3K regulatory unit p85 to HER3 and downstream Akt activity even after androgen depletion. Furthermore, in a LNCaP mouse xenograft model, the MP470-Erlotinib combination produced 30–65% dose-dependent tumor growth inhibition (TGI). We propose that MP470-Erlotinib targets the HER family/PI3K/Akt pathway and may represent a novel therapeutic strategy for prostate cancer

  7. Tyrosine 402 Phosphorylation of Pyk2 Is Involved in Ionomycin-Induced Neurotransmitter Release

    OpenAIRE

    Zhao Zhang; Yun Zhang; Zheng Mou; Shifeng Chu; Xiaoyu Chen; Wenbin He; Xiaofeng Guo; Yuhe Yuan; Masami Takahashi; Naihong Chen

    2014-01-01

    Protein tyrosine kinases, which are highly expressed in the central nervous system, are implicated in many neural processes. However, the relationship between protein tyrosine kinases and neurotransmitter release remains unknown. In this study, we found that ionomycin, a Ca²⁺ ionophore, concurrently induced asynchronous neurotransmitter release and phosphorylation of a non-receptor protein tyrosine kinase, proline-rich tyrosine kinase 2 (Pyk2), in clonal rat pheochromocytoma PC12 cells and ce...

  8. Proximity Utilizing Biotinylation of Nuclear Proteins in vivo

    Directory of Open Access Journals (Sweden)

    Arman Kulyyassov

    2015-06-01

    Full Text Available Introduction. The human genome consists of roughly 30,000 genes coding for over 500,000 different proteins, of which more than 10,000 proteins can be produced by the cell at any given time (the cellular “proteome”. It has been estimated that over 80% of proteins do not operate alone, but in complexes. These protein-protein interactions (PPI are regulated by several mechanisms. For example, post-translational modifications (methylation, acetylation, phosphorylation, or ubiquitination or metal-binding can lead to conformational changes that alter the affinity and kinetic parameters of the interaction. Many PPIs are part of larger cellular networks of interactions or interactomes. Indeed, these interactions are at the core of the entire interactomics system of any living cell, and so, aberrant PPIs are the basis of multiple diseases, such as neurodegenerative diseases and cancer. The objective of this study was to develop a method of monitoring protein-protein interactions and proximity dependence in vivo.Methods. The biotin ligase BirA was fused to the protein of interest, and the Biotin Acceptor Peptide (BAP was fused to an interacting partner to make the detection of its biotinylation possible by western blot or mass spectrometry.Results. Using several experimental systems (BirA.A + BAP.B, we showed that the biotinylation is interaction/proximity dependent. Here, A and B are the next nuclear proteins used in the experiments – 3 paralogues of heterochromatin protein HP1a (CBX5, HP1b (CBX1, HP1g (CBX3, wild type and transcription mutant factor Kap1, translesion DNA polymerase PolH and E3, ubiquitin ligase RAD18, Proliferative Cell Nuclear Antigen (PCNA, ubiquitin Ub, SUMO-2/3, different types and isoforms of histones H2A, H2Az, H3.1, H3.3, CenpA, H2A.BBD, and macroH2A. The variant of this approach is termed PUB-NChIP (Proximity Utilizing Biotinylation with Native Chromatin Immuno-precipitation and is designed to purify and study the protein

  9. Tyrosine kinase signalling in breast cancer

    International Nuclear Information System (INIS)

    Cells are continuously exposed to diverse stimuli ranging from soluble endocrine and paracrine factors to signalling molecules on neighbouring cells. Receptors of the tyrosine kinase family play an important role in the integration and interpretation of these external stimuli, allowing a cell to respond appropriately to its environment. The activation of receptor tyrosine kinases (RTKs) is tightly controlled, allowing a normal cell to correctly integrate its external environment with internal signal transduction pathways. In contrast, due to numerous molecular alterations arising during the course of malignancy, a tumour is characterized by an abnormal response to its environment, which allows cancer cells to evade the normal mechanisms controlling cellular proliferation. Alterations in the expression of various RTKs, in their activation, and in the signalling molecules lying downstream of the receptors play important roles in the development of cancer. This topic is the major focus of the thematic review section of this issue of Breast Cancer Research

  10. Buoyancy-activated cell sorting using targeted biotinylated albumin microbubbles.

    Directory of Open Access Journals (Sweden)

    Yu-Ren Liou

    Full Text Available Cell analysis often requires the isolation of certain cell types. Various isolation methods have been applied to cell sorting, including fluorescence-activated cell sorting and magnetic-activated cell sorting. However, these conventional approaches involve exerting mechanical forces on the cells, thus risking cell damage. In this study we applied a novel isolation method called buoyancy-activated cell sorting, which involves using biotinylated albumin microbubbles (biotin-MBs conjugated with antibodies (i.e., targeted biotin-MBs. Albumin MBs are widely used as contrast agents in ultrasound imaging due to their good biocompatibility and stability. For conjugating antibodies, biotin is conjugated onto the albumin MB shell via covalent bonds and the biotinylated antibodies are conjugated using an avidin-biotin system. The albumin microbubbles had a mean diameter of 2 μm with a polydispersity index of 0.16. For cell separation, the MDA-MB-231 cells are incubated with the targeted biotin-MBs conjugated with anti-CD44 for 10 min, centrifuged at 10 g for 1 min, and then allowed 1 hour at 4 °C for separation. The results indicate that targeted biotin-MBs conjugated with anti-CD44 antibodies can be used to separate MDA-MB-231 breast cancer cells; more than 90% of the cells were collected in the MB layer when the ratio of the MBs to cells was higher than 70:1. Furthermore, we found that the separating efficiency was higher for targeted biotin-MBs than for targeted avidin-incorporated albumin MBs (avidin-MBs, which is the most common way to make targeted albumin MBs. We also demonstrated that the recovery rate of targeted biotin-MBs was up to 88% and the sorting purity was higher than 84% for a a heterogenous cell population containing MDA-MB-231 cells (CD44(+ and MDA-MB-453 cells (CD44-, which are classified as basal-like breast cancer cells and luminal breast cancer cells, respectively. Knowing that the CD44(+ is a commonly used cancer

  11. Buoyancy-activated cell sorting using targeted biotinylated albumin microbubbles.

    Science.gov (United States)

    Liou, Yu-Ren; Wang, Yu-Hsin; Lee, Chia-Ying; Li, Pai-Chi

    2015-01-01

    Cell analysis often requires the isolation of certain cell types. Various isolation methods have been applied to cell sorting, including fluorescence-activated cell sorting and magnetic-activated cell sorting. However, these conventional approaches involve exerting mechanical forces on the cells, thus risking cell damage. In this study we applied a novel isolation method called buoyancy-activated cell sorting, which involves using biotinylated albumin microbubbles (biotin-MBs) conjugated with antibodies (i.e., targeted biotin-MBs). Albumin MBs are widely used as contrast agents in ultrasound imaging due to their good biocompatibility and stability. For conjugating antibodies, biotin is conjugated onto the albumin MB shell via covalent bonds and the biotinylated antibodies are conjugated using an avidin-biotin system. The albumin microbubbles had a mean diameter of 2 μm with a polydispersity index of 0.16. For cell separation, the MDA-MB-231 cells are incubated with the targeted biotin-MBs conjugated with anti-CD44 for 10 min, centrifuged at 10 g for 1 min, and then allowed 1 hour at 4 °C for separation. The results indicate that targeted biotin-MBs conjugated with anti-CD44 antibodies can be used to separate MDA-MB-231 breast cancer cells; more than 90% of the cells were collected in the MB layer when the ratio of the MBs to cells was higher than 70:1. Furthermore, we found that the separating efficiency was higher for targeted biotin-MBs than for targeted avidin-incorporated albumin MBs (avidin-MBs), which is the most common way to make targeted albumin MBs. We also demonstrated that the recovery rate of targeted biotin-MBs was up to 88% and the sorting purity was higher than 84% for a a heterogenous cell population containing MDA-MB-231 cells (CD44(+)) and MDA-MB-453 cells (CD44-), which are classified as basal-like breast cancer cells and luminal breast cancer cells, respectively. Knowing that the CD44(+) is a commonly used cancer-stem-cell biomarker, our

  12. Biotinylated vanadium and chromium sulfide nanoparticles as probes for colocalization of membrane proteins.

    Science.gov (United States)

    Loukanov, Alexandre; Emin, Saim

    2016-09-01

    We report the microemulsion synthesis of vanadium and chromium sulfide nanoparticles (NPs) and their biological application as nanoprobes for colocalization of membrane proteins. Spherical V2 S3 and Cr2 S3 NPs were prepared in reverse microemulsion droplets, as nanoreactors, obtained by the surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in nonpolar organic phase (heptane). Electron microscopic data indicated that the size distribution of the nanoparticles was uniform with an average diameter between 3 ÷ 5 nm. The prepared hydrophobic nanocrystals were transferred in aqueous phase by surface cap exchange of AOT with biotin-dihydrolipoic ligands. This substitution allows the nanoparticles solubility in aqueous solutions and confer their bioactivity. In addition, we report the conjugation procedure between α-Lipoic acid (LA) and biotin (abbreviated as biotin-LA). The biotin-LA structure was characterized by 1D and 2D NMR spectroscopy. The biotinylated vanadium and chromium sulfide nanoparticles were tested as probes for colocalization of glutamate receptors on sodium-dodecyl-sulfate-digested replica prepared from rat hippocampus. The method suggests their high labeling efficiency for study of membrane biological macromolecules. Microsc. Res. Tech. 79:799-805, 2016. © 2016 Wiley Periodicals, Inc. PMID:27312069

  13. Impact of adjuvant inhibition of vascular endothelial growth factor receptor tyrosine kinases on tumor growth delay and local tumor control after fractionated irradiation in human squamous cell carcinomas in nude mice

    International Nuclear Information System (INIS)

    Purpose: Previous experiments have shown that adjuvant inhibition of the vascular endothelial growth factor receptor after fractionated irradiation prolonged tumor growth delay and may also improve local tumor control. To test the latter hypothesis, local tumor control experiments were performed. Methods and materials: Human FaDu and UT-SCC-14 squamous cell carcinomas were studied in nude mice. The vascular endothelial growth factor receptor tyrosine kinase inhibitor PTK787/ZK222584 (50 mg/kg body weight b.i.d.) was administered for 75 days after irradiation with 30 fractions within 6 weeks. Tumor growth time and tumor control dose 50% (TCD50) were determined and compared to controls (carrier without PTK787/ZK222584). Results: Adjuvant administration of PTK787/ZK222584 significantly prolonged tumor growth time to reach 5 times the volume at start of drug treatment by an average of 11 days (95% confidence interval 0.06;22) in FaDu tumors and 29 days (0.6;58) in UT-SCC-14 tumors. In both tumor models, TCD50 values were not statistically significantly different between the groups treated with PTK787/ZK222584 compared to controls. Conclusions: Long-term inhibition of angiogenesis after radiotherapy significantly reduced the growth rate of local recurrences but did not improve local tumor control. This indicates that recurrences after irradiation depend on vascular endothelial growth factor-driven angiogenesis, but surviving tumor cells retain their clonogenic potential during adjuvant antiangiogenic treatment with PTK787/ZK222584

  14. Biotinylated dextran amine anterograde tracing of the canine corticospinal tract

    Institute of Scientific and Technical Information of China (English)

    Xiao Han; Guangming Lv; Huiqun Wu; Dafeng Ji; Zhou Sun; Yaofu Li; Lemin Tang

    2012-01-01

    In this study, biotinylated dextran amine (BDA) was microinjected into the left cortical motor area of the canine brain. Fluorescence microscopy results showed that a large amount of BDA-labeled pyramidal cells were visible in the left cortical motor area after injection. In the left medulla oblongata, the BDA-labeled corticospinal tract was evenly distributed, with green fluorescence that had a clear boundary with the surrounding tissue. The BDA-positive corticospinal tract entered into the right lateral funiculus of the spinal cord and descended into the posterior part of the right lateral funiculus, close to the posterior horn, from cervical to sacral segments. There was a small amount of green fluorescence in the sacral segment. The distribution of BDA labeling in the canine central nervous system was consistent with the course of the corticospinal tract. Fluorescence labeling for BDA gradually diminished with time after injection. Our findings indicate that the BDA anterograde tracing technique can be used to visualize the localization and trajectory of the corticospinal tract in the canine central nervous system.

  15. The Tyrosine Kinome Dictates Breast Cancer Heterogeneity and Therapeutic Responsiveness.

    Science.gov (United States)

    Ha, Jacqueline R; Siegel, Peter M; Ursini-Siegel, Josie

    2016-09-01

    Phospho-tyrosine signaling networks control numerous biological processes including cellular differentiation, cell growth and survival, motility, and invasion. Aberrant regulation of the tyrosine kinome is a hallmark of malignancy and influences all stages of breast cancer progression, from initiation to the development of metastatic disease. The success of specific tyrosine kinase inhibitors strongly validates the clinical relevance of tyrosine phosphorylation networks in breast cancer pathology. However, a significant degree of redundancy exists within the tyrosine kinome. Numerous receptor and cytoplasmic tyrosine kinases converge on a core set of signaling regulators, including adaptor proteins and tyrosine phosphatases, to amplify pro-tumorigenic signal transduction pathways. Mutational activation, amplification, or overexpression of one or more components of the tyrosine kinome represents key contributing events responsible for the tumor heterogeneity that is observed in breast cancers. It is this molecular heterogeneity that has become the most significant barrier to durable clinical responses due to the development of therapeutic resistance. This review focuses on recent literature that supports a prominent role for specific components of the tyrosine kinome in the emergence of unique breast cancer subtypes and in shaping breast cancer plasticity, sensitivity to targeted therapies, and the eventual emergence of acquired resistance. J. Cell. Biochem. 117: 1971-1990, 2016. © 2016 Wiley Periodicals, Inc. PMID:27392311

  16. K12-biotinylated Histone H4 Marks Heterochromatin in Human Lymphoblastoma Cells1

    OpenAIRE

    Camporeale, Gabriela; Oommen, Anna M; Griffin, Jacob B.; Sarath, Gautam; Zempleni, Janos

    2007-01-01

    Covalent modifications of histones play crucial roles in chromatin structure and genomic stability. Recently, we reported a novel modification of histones: biotinylation of lysine residues. Here we provide evidence that K12-biotinylated histone H4 (K12Bio H4) maps specifically to both heterochromatin (alpha satellite repeats in pericentromeric regions) and transcriptionally repressed chromatin (γ-G globin and interleukin-2) in human lymphoblastoma cells. The abundance of K12Bio H4 in these re...

  17. Ultrastructural and biochemical detection of biotin and biotinylated polypeptides in Schistosoma mansoni

    OpenAIRE

    1997-01-01

    Biotinylation is proposed for the identification of surface proteins in Schistosoma mansoni using the streptavidin-HRP conjugate for the detection of labeled polypeptides. However, control samples also showed several endogenous biotinylated polypeptides. In an attempt to determine the possibility of nonspecific binding between the streptavidin-HRP conjugate and polypeptides from S. mansoni, the conjugate was blocked with biotinamidecaproate-N-hydroxysuccinimide ester (BcapNHS) before biotin-s...

  18. Metabolic biotinylation of recombinant antibody by biotin ligase retained in the endoplasmic reticulum

    OpenAIRE

    Barat, Bhaswati; Anna M. Wu

    2007-01-01

    Due to its strength and specificity, the interaction between avidin and biotin has been used in a variety of scientific and medical applications ranging from immunohistochemistry to drug targeting. The present study describes two methods for biotinylation of proteins secreted from eukaryotic cells using the E. coli biotin protein ligase. In one system the biotin ligase was co-secreted from the cells along with substrate protein enabling extracellular biotinylation of the tagged protein. In th...

  19. Noncovalent Immobilization of Streptavidin on In Vitro- and In Vivo-Biotinylated Bacterial Magnetic Particles▿

    OpenAIRE

    Maeda, Yoshiaki; Yoshino, Tomoko; Takahashi, Masaaki; Ginya, Harumi; Asahina, Junko; Tajima, Hideji; Matsunaga, Tadashi

    2008-01-01

    Biotinylated magnetic nanoparticles were constructed by displaying biotin acceptor peptide (BAP) or biotin carboxyl carrier protein (BCCP) on the surface of bacterial magnetic particles (BacMPs) synthesized by Magnetospirillum magneticum AMB-1. BAP-displaying BacMPs (BAP-BacMPs) were extracted from bacterial cells and incubated with biotin and Escherichia coli biotin ligase. Then the in vitro biotinylation of BAP-BacMPs was confirmed using alkaline phosphatase-labeled antibiotin antibody. In ...

  20. The Role of MET Receptor Tyrosine Kinase in Non-Small Cell Lung Cancer and Clinical Development of Targeted Anti-MET Agents

    OpenAIRE

    Robinson, Kyle W.; Sandler, Alan B.

    2013-01-01

    The role of MET in the pathophysiology of non-small cell lung cancer and in acquired resistance to epidermal growth factor receptor inhibitors is summarized. An update on progress in the clinical development of inhibitors of MET for treatment of non-small cell lung cancer is provided.

  1. The expression of a novel receptor-type tyrosine phosphatase suggests a role in morphogenesis and plasticity of the nervous system

    DEFF Research Database (Denmark)

    Canoll, P D; Barnea, G; Levy, J B;

    1993-01-01

    adult, high levels of RPTP-beta are seen in regions of the brain where there is continued neurogenesis and neurite outgrowth. The spatial and temporal patterns of RPTP-beta expression suggest that this receptor phosphatase plays a role in morphogenesis and plasticity of the nervous system....

  2. Angiotensin II type 1 receptors stimulate protein synthesis in human cardiac fibroblasts via a Ca2+-sensitive PKC-dependent tyrosine kinase pathway

    DEFF Research Database (Denmark)

    Hou, M; Pantev, E; Möller, S;

    2000-01-01

    ) was obtained at a concentration of 10 nM. There were no significant alterations of cell number or total protein content, suggesting that Ang II stimulated protein synthesis but did not induce hypertrophy. The accumulation of 3H-leucine was blocked by the AT1 receptor antagonist candesartan but not by...

  3. Endothelin-1 induces VCAM-1 expression-mediated inflammation via receptor tyrosine kinases and Elk/p300 in human tracheal smooth muscle cells.

    Science.gov (United States)

    Lin, Chih-Chung; Lin, Wei-Ning; Hou, Wei-Chen; Hsiao, Li-Der; Yang, Chuen-Mao

    2015-08-01

    The elevated level of endothelin-1 (ET-1) has been detected in the bronchoalveolar lavage of patients with severe asthma, acute lung injury, acute respiratory distress syndrome, and sepsis. ET-1 may affect vessel tone together with lung physiology and pathology. Vascular cell adhesion molecule-1 (VCAM-1) is one kind of adhesion molecules participating in the process of polymorphonuclear leukocyte transmigration and regulating the occurrence and amplification of tissue inflammation. However, the molecular mechanisms underlying ET-1-mediated expression of VCAM-1 on human tracheal smooth muscle cells (HTSMCs) were largely unknown. Here we reported that ET-1 stimulated expression of VCAM-1 gene on HTSMCs, which was blocked by pretreatment with the inhibitors of ET receptors, Src, matrix metalloproteinases (MMPs), epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFR), phosphatidylinositol 3-kinase (PI3K), AKT, MEK1/2, and p300, suggesting the participation of these signaling components in ET-1-regulated HTSMC responses. Furthermore, transfection with small-interfering RNA (siRNA) of Src, AKT, p42 mitogen-activated protein kinase (MAPK), or p300 downregulated the respective proteins and significantly attenuated ET-1-induced VCAM-1 expression. ET-1 also stimulated phosphorylation of Src, EGFR, PDGFR, AKT, p42/p44 MAPK, and Elk-1 and acetylation of histone H4 on HTSMCs. Immunoprecipitation assay showed the association between Elk-1 and p300 in the nucleus. Adhesion assay revealed that the adhesion of THP-1 to HTSMCs challenged with ET-1 was increased, which was attenuated by the inhibitors of ET receptors, Src, MMPs, EGFR, PDGFR, PI3K, AKT, p42/p44 MAPK, and p300. Taken together, these data suggested that ET-1 promotes occurrence and amplification of pathology-related airway inflammation via enhancing VCAM-1 expression in an ET receptor/Src/MMP/EGFR, PDGFR/PI3K/AKT/p42/p44 MAPK/Elk-1/p300 pathway in HTSMCs. PMID:26071554

  4. Inhibition of protein tyrosine phosphatase activity mediates epidermal growth factor receptor signaling in human airway epithelial cells exposed to Zn2+

    International Nuclear Information System (INIS)

    Epidemiological studies have implicated zinc (Zn2+) in the toxicity of ambient particulate matter (PM) inhalation. We previously showed that exposure to metal-laden PM inhibits protein tyrosine phosphatase (PTP) activity in human primary bronchial epithelial cells (HAEC) and leads to Src-dependent activation of EGFR signaling in B82 and A431 cells. In order to elucidate the mechanism of Zn2+-induced EGFR activation in HAEC, we treated HAEC with 500 μM ZnSO4 for 5-20 min and measured the state of activation of EGFR, c-Src and PTPs. Western blots revealed that exposure to Zn2+ results in increased phosphorylation at both trans- and autophosphorylation sites in the EGFR. Zn2+-mediated EGFR phosphorylation did not require ligand binding and was ablated by the EGFR kinase inhibitor PD153035, but not by the Src kinase inhibitor PP2. Src activity was inhibited by Zn2+ treatment of HAEC, consistent with Src-independent EGFR transactivation in HAEC exposed to Zn2+. The rate of exogenous EGFR dephosphorylation in lysates of HAEC exposed to Zn2+ or V4+ was significantly diminished. Moreover, exposure of HAEC to Zn2+ also resulted in a significant impairment of dephosphorylation of endogenous EGFR. These data show that Zn2+-induced activation of EGFR in HAEC involves a loss of PTP activities whose function is to dephosphorylate EGFR in opposition to baseline EGFR kinase activity. These findings also suggest that there are marked cell-type-specific differences in the mechanism of EGFR activation induced by Zn2+ exposure

  5. Fc gamma receptor activation induces the tyrosine phosphorylation of both phospholipase C (PLC)-gamma 1 and PLC-gamma 2 in natural killer cells

    OpenAIRE

    1992-01-01

    Crosslinking of the low affinity immunoglobulin G (IgG) Fc receptor (Fc gamma R type III) on natural killer (NK) cells initiates antibody- dependent cellular cytotoxicity. During this process, Fc gamma R stimulation results in the rapid activation of phospholipase C (PLC), which hydrolyzes membrane phosphoinositides, generating inositol-1,4,5- trisphosphate and sn-1,2-diacylglycerol as second messengers. We have recently reported that PLC activation after Fc gamma R stimulation can be inhibit...

  6. Activity Assay of Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Triple-Negative Breast Cancer Cells Using Peptide-Conjugated Magnetic Beads

    OpenAIRE

    Ghosh, Gargi; Yan, Xiaoliang; Kron, Stephen J.; Palecek, Sean P.

    2013-01-01

    Triple-negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer with limited treatment options. Epidermal growth factor receptor I (EGFR) has emerged as a promising target in TNBC. Limited success of the EGFR kinase inhibiting small molecules in clinical trials may be attributed in part to inaccuracy in identifying EGFR signatures in patient tumors. In light of the absence of a simple correlation between EGFR expression and its degree of activation, a simple and reliable ...

  7. The monomeric alpha beta form of the insulin receptor exhibits much higher insulin-dependent tyrosine-specific protein kinase activity than the intact alpha 2 beta 2 form of the receptor.

    OpenAIRE

    Fujita-Yamaguchi, Y; Kathuria, S.

    1985-01-01

    The relationship between the structure of the insulin receptor and its kinase activity was studied on the purified receptor treated with different concentrations of dithiothreitol. An enhanced autophosphorylation of the beta subunit (Mr, 90,000) was observed on NaDodSO4/PAGE under reducing conditions when the receptor was treated with 0.1-0.75 mM dithiothreitol in the presence of 1 microM insulin. Since we have previously observed (unpublished data) that incubation of the purified receptor wi...

  8. Redox Regulation of Protein Tyrosine Phosphatase Activity by Hydroxyl Radical

    OpenAIRE

    Meng, Fan-Guo; Zhang, Zhong-Yin

    2012-01-01

    Substantial evidence suggests that transient production of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) is an important signaling event triggered by the activation of various cell surface receptors. Major targets of H2O2 include protein tyrosine phosphatases (PTPs). Oxidation of the active site Cys by H2O2 abrogates PTP catalytic activity, thereby potentially furnishing a mechanism to ensure optimal tyrosine phosphorylation in response to a variety of physiological stimuli. ...

  9. Novel 2,7-Substituted (S)-1,2,3,4-Tetrahydroisoquinoline-3-carboxylic Acids: Peroxisome Proliferator-Activated Receptor γ Partial Agonists with Protein-Tyrosine Phosphatase 1B Inhibition.

    Science.gov (United States)

    Otake, Kazuya; Azukizawa, Satoru; Takeda, Shigemitsu; Fukui, Masaki; Kawahara, Arisa; Kitao, Tatsuya; Shirahase, Hiroaki

    2015-01-01

    A novel series of 2,7-substituted 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid derivatives were synthesized and biologically evaluated. (S)-2-(2-Furylacryloyl)-7-[2-(2-methylindane-2-yl)-5-methyloxazol-4-yl]methoxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid tert-butylamine salt (13jE) was identified as a potent human peroxisome proliferator-activated receptor γ (PPARγ)-selective agonist (EC50=85 nM) and human protein-tyrosine phosphatase 1B (PTP-1B) inhibitor (IC50=1.0 µM). Compound 13jE partially activated PPARγ, but not PPARα or PPARδ, and antagonized farglitazar, a full PPARγ agonist. Cmax after the oral administration of 13jE at 10 mg/kg was 28.6 µg/mL (53 µM) in male Sprague-Dawley (SD) rats. Repeated administration of 13jE and rosiglitazone for 14 d at 10 mg/kg/d decreased plasma glucose and triglyceride levels significantly in male KK-A(y) mice. Rosiglitazone, but not 13jE, significantly increased the plasma volume and liver weight. In conclusion, 13jE showed stronger hypoglycemic and hypolipidemic effects and weaker hemodilution and hepatotoxic effects than rosiglitazone, suggesting that its safer efficacy may be due to its partial PPARγ agonism and PTP-1B inhibition. PMID:26633022

  10. Activation of the IGF1R pathway potentially mediates acquired resistance to mutant-selective 3rd-generation EGF receptor tyrosine kinase inhibitors in advanced non-small cell lung cancer.

    Science.gov (United States)

    Park, Ji Hyun; Choi, Yun Jung; Kim, Seon Ye; Lee, Jung-Eun; Sung, Ki Jung; Park, Sojung; Kim, Woo Sung; Song, Joon Seon; Choi, Chang-Min; Sung, Young Hoon; Rho, Jin Kyung; Lee, Jae Cheol

    2016-04-19

    Mutant-selective, 3rd-generation EGFR-TKIs were recently developed to control lung cancer cells harboring T790M-mediated resistance. However, the development of resistance to these novel drugs seems inevitable. Thus, we investigated the mechanism of acquired resistance to the mutant-selective EGFR-TKI WZ4002. We established five WZ4002-resistant cells, derived from cells harboring both EGFR and T790M mutations by long-term exposure to increasing doses of WZ4002. Compared with the parental cells, all resistant cells showed 10-100-folds higher resistance to WZ4002, as well as cross-resistance to other mutant-selective inhibitors. Among them, three resistant cells (HCC827/WR, PC-9/WR and H1975/WR) showed dependency on EGFR signaling, but two other cells (PC-9/GR/WR and PC-9/ER/WR) were not. Notably, insulin-like growth factor-1 receptor (IGF1R) was aberrantly activated in PC-9/GR/WR cells in phospho-receptor tyrosine kinase array, consistently accompanied by loss of IGF binding protein-3 (IGFBP3). Down-regulation of IGF1R by shRNA, as well as inhibition of IGF1R activity either by AG-1024 (a small molecule IGF1R inhibitor) or BI 836845 (a monoclonal anti-IGF1/2 blocking antibody), restored the sensitivity to WZ4002 both in vitro and xenograft. Taken together, these results suggest that activation of the IGF1R pathway associated with IGFBP3 loss can induce an acquired resistance to the mutant-selective EGFR-TKI, WZ4002. Therefore, a combined therapy of IGF1R inhibitors and mutant-selective EGFR-TKIs might be a viable treatment strategy for overcoming acquired resistance. PMID:26980747

  11. Production of recombinant insulin-like androgenic gland hormones from three decapod species: In vitro testicular phosphorylation and activation of a newly identified tyrosine kinase receptor from the Eastern spiny lobster, Sagmariasus verreauxi.

    Science.gov (United States)

    Aizen, Joseph; Chandler, Jennifer C; Fitzgibbon, Quinn P; Sagi, Amir; Battaglene, Stephen C; Elizur, Abigail; Ventura, Tomer

    2016-04-01

    In crustaceans the insulin-like androgenic gland hormone (IAG) is responsible for male sexual differentiation. To date, the biochemical pathways through which IAG exerts its effects are poorly understood and could be elucidated through the production of a functional recombinant IAG (rIAG). We have successfully expressed glycosylated, biologically active IAG using the Pichia pastoris yeast expression system. We co-expressed recombinant single-chain precursor molecules consisting of the B and A chains (the mature hormone) tethered by a flexible linker, producing rIAGs of the following commercially important species: Eastern spiny lobster Sagmariasus verreauxi (Sv), redclaw crayfish Cherax quadricarinatus (Cq) and giant freshwater prawn Macrobrachium rosenbergii (Mr). We then tested the biological activity of each, through the ability to increase phosphorylation in the testis; both Sv and Cq rIAGs significantly elevated phosphorylation specific to their species, and in a dose-dependent manner. Mr rIAG was tested on Macrobrachium australiense (Ma), eliciting a similar response. Moreover, using bioinformatics analyses of the de novo assembled spiny lobster transcriptome, we identified a spiny lobster tyrosine kinase insulin receptor (Sv-TKIR). We validated this discovery with a receptor activation assay in COS-7 cells expressing Sv-TKIR, using a reporter SRE-LUC system designed for RTKs, with each of the rIAG proteins acting as the activation ligand. Using recombinant proteins, we aim to develop specific tools to control sexual development through the administration of IAG within the critical sexual differentiation time window. The biologically active rIAGs generated might facilitate commercially feasible solutions for the long sought techniques for sex-change induction and monosex population culture in crustaceans and shed new light on the physiological mode of action of IAG in crustaceans. PMID:26883686

  12. Activation of the IGF1R pathway potentially mediates acquired resistance to mutant-selective 3rd-generation EGF receptor tyrosine kinase inhibitors in advanced non-small cell lung cancer

    Science.gov (United States)

    Park, Ji Hyun; Choi, Yun Jung; Kim, Seon Ye; Lee, Jung-Eun; Sung, Ki Jung; Park, Sojung; Kim, Woo Sung; Song, Joon Seon; Choi, Chang-Min; Sung, Young Hoon; Rho, Jin Kyung; Lee, Jae Cheol

    2016-01-01

    Mutant-selective, 3rd-generation EGFR-TKIs were recently developed to control lung cancer cells harboring T790M-mediated resistance. However, the development of resistance to these novel drugs seems inevitable. Thus, we investigated the mechanism of acquired resistance to the mutant-selective EGFR-TKI WZ4002. We established five WZ4002-resistant cells, derived from cells harboring both EGFR and T790M mutations by long-term exposure to increasing doses of WZ4002. Compared with the parental cells, all resistant cells showed 10–100-folds higher resistance to WZ4002, as well as cross-resistance to other mutant-selective inhibitors. Among them, three resistant cells (HCC827/WR, PC-9/WR and H1975/WR) showed dependency on EGFR signaling, but two other cells (PC-9/GR/WR and PC-9/ER/WR) were not. Notably, insulin-like growth factor-1 receptor (IGF1R) was aberrantly activated in PC-9/GR/WR cells in phospho-receptor tyrosine kinase array, consistently accompanied by loss of IGF binding protein-3 (IGFBP3). Down-regulation of IGF1R by shRNA, as well as inhibition of IGF1R activity either by AG-1024 (a small molecule IGF1R inhibitor) or BI 836845 (a monoclonal anti-IGF1/2 blocking antibody), restored the sensitivity to WZ4002 both in vitro and xenograft. Taken together, these results suggest that activation of the IGF1R pathway associated with IGFBP3 loss can induce an acquired resistance to the mutant-selective EGFR-TKI, WZ4002. Therefore, a combined therapy of IGF1R inhibitors and mutant-selective EGFR-TKIs might be a viable treatment strategy for overcoming acquired resistance. PMID:26980747

  13. Force dependent biotinylation of myosin IIA by α-catenin tagged with a promiscuous biotin ligase.

    Directory of Open Access Journals (Sweden)

    Shuji Ueda

    Full Text Available Tissues and organs undergo constant physical perturbations and individual cells must respond to mechanical forces to maintain tissue integrity. However, molecular interactions underlying mechano-transduction are not fully defined at cell-cell junctions. This is in part due to weak and transient interactions that are likely prevalent in force-induced protein complexes. Using in situ proximal biotinylation by the promiscuous biotin ligase BirA tagged to α-catenin and a substrate stretch cell chamber, we sought to identify force-dependent molecular interactions surrounding α-catenin, an actin regulator at the sites of cadherin mediated cell-cell adhesion. While E-cadherin, β-catenin, vinculin and actin localize with α-catenin at cell-cell contacts in immuno-fluorescent staining, only β-catenin and plakoglobin were biotinylated, suggesting that this proximal biotinylation is limited to the molecules that are in the immediate vicinity of α-catenin. In mechanically stretched samples, increased biotinylation of non-muscle myosin IIA, but not myosin IIB, suggests close spatial proximity between α-catenin and myosin IIA during substrate stretching. This force-induced biotinylation diminished as myosin II activity was inhibited by blebbistatin. Taken together, this promising technique enables us to identify force sensitive complexes that may be essential for mechano-responses in force bearing cell adhesion.

  14. Force dependent biotinylation of myosin IIA by α-catenin tagged with a promiscuous biotin ligase.

    Science.gov (United States)

    Ueda, Shuji; Blee, Alexandra M; Macway, Katherine G; Renner, Derrick J; Yamada, Soichiro

    2015-01-01

    Tissues and organs undergo constant physical perturbations and individual cells must respond to mechanical forces to maintain tissue integrity. However, molecular interactions underlying mechano-transduction are not fully defined at cell-cell junctions. This is in part due to weak and transient interactions that are likely prevalent in force-induced protein complexes. Using in situ proximal biotinylation by the promiscuous biotin ligase BirA tagged to α-catenin and a substrate stretch cell chamber, we sought to identify force-dependent molecular interactions surrounding α-catenin, an actin regulator at the sites of cadherin mediated cell-cell adhesion. While E-cadherin, β-catenin, vinculin and actin localize with α-catenin at cell-cell contacts in immuno-fluorescent staining, only β-catenin and plakoglobin were biotinylated, suggesting that this proximal biotinylation is limited to the molecules that are in the immediate vicinity of α-catenin. In mechanically stretched samples, increased biotinylation of non-muscle myosin IIA, but not myosin IIB, suggests close spatial proximity between α-catenin and myosin IIA during substrate stretching. This force-induced biotinylation diminished as myosin II activity was inhibited by blebbistatin. Taken together, this promising technique enables us to identify force sensitive complexes that may be essential for mechano-responses in force bearing cell adhesion. PMID:25806963

  15. Identification of a novel immunoreceptor tyrosine-based activation motif-containing molecule, STAM2, by mass spectrometry and its involvement in growth factor and cytokine receptor signaling pathways

    DEFF Research Database (Denmark)

    Pandey, A; Fernandez, M M; Steen, H;

    2000-01-01

    molecule containing a Src homology 3 domain as well as an immunoreceptor tyrosine-based activation motif (ITAM). This molecule is 55% identical to a previously isolated molecule designated signal transducing adaptor molecule (STAM) that was identified as an interleukin (IL)-2-induced phosphoprotein and is...... therefore designated STAM2. Tyrosine phosphorylation of STAM2 is induced by growth factors such as epidermal growth factor and platelet-derived growth factor as well as by cytokines like IL-3. Several of the deletion mutants tested except the one containing only the amino-terminal region underwent tyrosine...... phosphorylation upon growth factor stimulation, implying that STAM2 is phosphorylated on several tyrosine residues. STAM2 is downstream of the Jak family of kinases since coexpression of STAM2 with Jak1 or Jak2 but not an unrelated Tec family kinase, Etk, resulted in its tyrosine phosphorylation. In contrast to...

  16. Point mutation of tyrosine 759 of the IL-6 family cytokine receptor, gp130, augments collagen-induced arthritis in DBA/1J mice

    Directory of Open Access Journals (Sweden)

    Ishihara Katsuhiko

    2009-02-01

    Full Text Available Abstract Background Knock-in mice (gp130F759 with a Y759F point mutation in gp130, a signal transducing receptor subunit shared by members of the IL-6 cytokine family, show sustained activation of STAT3, enhanced acute-phase or immune responses, and autoimmune arthritis. We conducted a detailed analysis of collagen-induced arthritis (CIA in gp130F759 with a DBA/1J background (D/J.gp130F759. Methods We backcrossed gp130F759 to C57BL/6 and DBA/1J, and compared the pathologic changes, including occurrence of arthritis, in the two distinct genetic backgrounds. We analyzed CIA in D/J.gp130F759 and investigated the effects of methotrexate (MTX on CIA. Results C57BL/6 background gp130F759 mice, but not D/J.gp130F759, spontaneously developed polyarthritis and glomerulonephritis. On the other hand, keratitis of the eyes only developed in D/J.gp130F759, indicating the influence of genetic background on disease development in gp130F759 mice. Resistance of the DBA/1J background against spontaneous arthritis urged us to examine CIA in D/J.gp130F759. CIA in D/J.gp130F759 was more severe, with greater bone destruction, than the control mice. After collagen immunization, splenomegaly and serum levels of rheumatoid factor and anti-DNA antibody were augmented in D/J.gp130F759. Bio-Plex analysis of serum cytokines revealed increased IL-12p40 and PDGF-BB before immunization, and increased levels of IFN-γ, IL-17, TNF-α, IL-9, and MIP-1β 8 days after the booster dose. IL-6 and PDGF-BB in D/J.gp130F759 showed distinct kinetics from the other cytokines; higher levels were observed after arthritis development. MTX partially attenuated the development of arthritis and inhibited bone destruction in D/J.gp130F759, with reduction of anti-type II collagen antibody levels, suggesting that MTX mainly affects antigen-specific immune responses in CIA. Conclusion The Tyr-759 point mutation of the IL-6 family cytokine receptor subunit, gp130, caused autoimmune disease, and this

  17. Counting NMDA Receptors at the Cell Surface

    Czech Academy of Sciences Publication Activity Database

    Horák, Martin; Suh, Y. H.

    Totowa: Humana Press Inc., 2016, s. 31-44. (Neuromethods. 106). ISBN 978-1-4939-2811-8 R&D Projects: GA ČR(CZ) GA14-02219S Institutional support: RVO:67985823 Keywords : NMDA receptor * ionotropic glutamate receptor * mammalian cell lines * intracellular trafficking * quantitative assay * biotinylation assay * biochemistry Subject RIV: FH - Neurology

  18. Autophosphorylation of JAK2 on tyrosines 221 and 570 regulates its activity

    DEFF Research Database (Denmark)

    Argetsinger, Lawrence S; Kouadio, Jean-Louis K; Steen, Hanno; Stensballe, Allan; Jensen, Ole N; Carter-Su, Christin

    2004-01-01

    The tyrosine kinase JAK2 is a key signaling protein for at least 20 receptors in the cytokine/hematopoietin receptor superfamily and is a component of signaling by insulin receptor and several G-protein-coupled receptors. However, there is only limited knowledge of the physical structure of JAK2 ...

  19. Predictive value of hypoxia, proliferation and tyrosine kinase receptors for EGFR-inhibition and radiotherapy sensitivity in head and neck cancer models

    International Nuclear Information System (INIS)

    Background and purpose: EGFR-inhibitor Cetuximab (C225) improves the efficacy of radiotherapy in only a subgroup of HNSCC patients. Identification of predictive tumor characteristics is essential to improve patient selection. Material and methods: Response to C225 and/or radiotherapy was assessed with tumor growth delay assays in 4 HNSCC xenograft models with varying EGFR-expression levels. Hypoxia and proliferation were quantified with immunohistochemistry and the expression of proteins involved in C225-resistance with Western blot. Results: EGFR-expression did not predict response to C225 and/or radiotherapy. Reduction of hypoxia by C225 was only observed in SCCNij202, which was highly sensitive to C225. Proliferation changes correlated with response to C225 and C225 combined with radiotherapy, as proliferation decreased after C225 treatment in C225-sensitive SCCNij202 and after combined treatment in SCCNij185, which showed a synergistic effect to combined C225-radiotherapy. Furthermore, C225-resistant SCCNij153 tumors expressed high levels of (activated) HER3 and MET. Conclusions: EGFR-expression is needed for C225-response, but is not sufficient to predict response to C225 with or without radiotherapy. However, basal expression of additional growth factor receptors and effects on proliferation, but not hypoxia, correlated with response to combined C225-radiotherapy treatment and are potential clinically relevant predictive biomarkers

  20. A novel reactive ester derivative of biotin with reduced membrane permeability for in vivo biotinylation experiments.

    Science.gov (United States)

    Strassberger, Verena; Trüssel, Sabrina; Fugmann, Tim; Neri, Dario; Roesli, Christoph

    2010-10-01

    The in vivo perfusion of rodent models of disease with biotin derivatives and the subsequent comparative proteomic analysis of healthy and diseased tissues represent a promising methodology for the identification of vascular accessible biomarkers. A novel, triply charged biotinylation reagent, NHS-β-Ala-(L-Asp)(3)-biotin, was synthesized and validated in terms of its applicability for in vivo protein biotinylation. Compared to sulfo-NHS-LC-biotin, NHS-β-Ala-(L-Asp)(3)-biotin exhibited a reduced membrane permeability and a preferential labeling of proteins localized in compartments readily accessible in vivo from the vasculature. PMID:20821733

  1. G1 cell cycle arrest due to the inhibition of erbB family receptor tyrosine kinases does not require the retinoblastoma protein

    International Nuclear Information System (INIS)

    The erbB receptor family (EGFr, erbB-2, erbB-3, and erbB-4) consists of transmembrane glycoproteins that transduce extracellular signals to the nucleus when activated. erbB family members are widely expressed in epithelial, mesenchymal, and neuronal cells and contribute to the proliferation, differentiation, migration, and survival of these cell types. The present study evaluates the effects of erbB family signaling on cell cycle progression and the role that pRB plays in regulating this process. ErbB family RTK activity was inhibited by PD 158780 in the breast epithelial cell line MCF10A. PD 158780 (0.5 μM) inhibited EGF-stimulated and heregulin-stimulated autophosphorylation and caused a G1 cell cycle arrest within 24 h, which correlated with hypophosporylation of pRB. MCF10A cells lacking functional pRB retained the ability to arrest in G1 when treated with PD 158780. Both cell lines showed induction of p27KIP1 protein when treated with PD 158780 and increased association of p27KIP1 with cyclin E-CDK2. Furthermore, CDK2 kinase activity was dramatically inhibited with drug treatment. Changes in other pRB family members were noted with drug treatment, namely a decrease in p107 and an increase in p130. These findings show that the G1 arrest induced through inhibition of erbB family RTK activity does not require functional pRB

  2. Species differences in the immunoreactive expression of oxytocin, vasopressin, tyrosine hydroxylase and estrogen receptor alpha in the brain of Mongolian gerbils (Meriones unguiculatus and Chinese striped hamsters (Cricetulus barabensis.

    Directory of Open Access Journals (Sweden)

    Yu Wang

    Full Text Available Species differences in neurochemical expression and activity in the brain may play an important role in species-specific patterns of social behavior. In the present study, we used immunoreactive (ir labeling to compare the regional density of cells containing oxytocin (OT, vasopressin (AVP, tyrosine hydroxylase (TH, or estrogen receptor alpha (ERα staining in the brains of social Mongolian gerbils (Meriones unguiculatus and solitary Chinese striped hamsters (Cricetulus barabensis. Multiple region- and neurochemical-specific species differences were found. In the anterior hypothalamus (AH, Mongolian gerbils had higher densities of AVP-ir and ERα-ir cells than Chinese striped hamsters. In the lateral hypothalamus (LH, Mongolian gerbils also had higher densities of AVP-ir and TH-ir cells, but a lower density of OT-ir cells, than Chinese striped hamsters. Furthermore, in the anterior nucleus of the medial preoptic area (MPOAa, Mongolian gerbils had higher densities of OT-ir and AVP-ir cells than Chinese striped hamsters, and an opposite pattern was found in the posterior nucleus of the MPOA (MPOAp. Some sex differences were also observed. Females of both species had higher densities of TH-ir cells in the MPOAa and of OT-ir cells in the intermediate nucleus of the MPOA (MPOAi than males. Given the role of these neurochemicals in social behaviors, our data provide additional evidence to support the notion that species-specific patterns of neurochemical expression in the brain may be involved in species differences in social behaviors associated with different life strategies.

  3. Activation of protein tyrosine phosphatase non-receptor type 2 by spermidine exerts anti-inflammatory effects in human THP-1 monocytes and in a mouse model of acute colitis.

    Directory of Open Access Journals (Sweden)

    Belén Morón

    Full Text Available BACKGROUND: Spermidine is a dietary polyamine that is able to activate protein tyrosine phosphatase non-receptor type 2 (PTPN2. As PTPN2 is known to be a negative regulator of interferon-gamma (IFN-γ-induced responses, and IFN-γ stimulation of immune cells is a critical process in the immunopathology of inflammatory bowel disease (IBD, we wished to explore the potential of spermidine for reducing pro-inflammatory effects in vitro and in vivo. METHODS: Human THP-1 monocytes were treated with IFN-γ and/or spermidine. Protein expression and phosphorylation were analyzed by Western blot, cytokine expression by quantitative-PCR, and cytokine secretion by ELISA. Colitis was induced in mice by dextran sodium sulfate (DSS administration. Disease severity was assessed by recording body weight, colonoscopy and histology. RESULTS: Spermidine increased expression and activity of PTPN2 in THP-1 monocytes and reduced IFN-γ-induced phosphorylation of signal transducer and activator of transcription (STAT 1 and 3, as well as p38 mitogen-activated protein kinase (MAPK in a PTPN2 dependent manner. Subsequently, IFN-γ-induced expression/secretion of intracellular cell adhesion molecule (ICAM-1 mRNA, monocyte chemoattractant protein (MCP-1, and interleukin (IL-6 was reduced in spermidine-treated cells. The latter effects were absent in PTPN2-knockdown cells. In mice with DSS-induced colitis, spermidine treatment resulted in ameliorated weight loss and decreased mucosal damage indicating reduced disease severity. CONCLUSIONS: Activation of PTPN2 by spermidine ameliorates IFN-γ-induced inflammatory responses in THP-1 cells. Furthermore, spermidine treatment significantly reduces disease severity in mice with DSS-induced colitis; hence, spermidine supplementation and subsequent PTPN2 activation may be helpful in the treatment of chronic intestinal inflammation such as IBD.

  4. In vivo biotinylation of recombinant beta-glucosidase enables simultaneous purification and immobilization on streptavidin coated magnetic particles

    DEFF Research Database (Denmark)

    Alftrén, Johan; Ottow, Kim Ekelund; Hobley, Timothy John

    2013-01-01

    Beta-glucosidase from Bacillus licheniformis was in vivo biotinylated in Escherichia coli and subsequently immobilized directly from cell lysate on streptavidin coated magnetic particles. In vivo biotinylation was mediated by fusing the Biotin Acceptor Peptide to the C-terminal of beta-glucosidas...

  5. Increased streptavidin uptake in tumors pretargeted with biotinylated antibody using a conjugate of streptavidin-Fab fragment

    International Nuclear Information System (INIS)

    Radiolabeled streptavidin accumulated in tumors pretargeted with biotinylated antibody. However, the absolute delivery of radioactivity was limited. To increase the tumor uptake of radioactivity further, we conjugated streptavidin with a mouse monoclonal antibody (MAb) fragment, OST6Fab, which recognizes antigen on human osteosarcoma. Another mouse MAb, OST7, which also reacts with the same tumor but recognizes an epitope different from the OST6 epitope, was biotinylated. The radioiodinated streptavidin-OST6Fab conjugate was administered to tumor-bearing mice after the biotinylated OST7 pretargeting. The uptake of the conjugate in tumors pretargeted with the biotinylated antibody was significantly higher than that of streptavidin and that of the conjugate of streptavidin and irrelevant Fab fragment. Renal uptake of radioactivity was decreased markedly, and the blood clearance was retarded by the conjugation with Fab fragment. In conclusion, the conjugate of streptavidin with specific Fab fragment increased the accumulation of radioactivity in tumors pretargeted with biotinylated antibody

  6. Treatment of Breast Cancer Cells by IGF1R Tyrosine Kinase Inhibitor Combined with Conventional Systemic Drugs

    NARCIS (Netherlands)

    Hartog, H.; Van der Graaf, W. T. A.; Boezen, H. M.; Wesseling, J.

    2012-01-01

    Aim: Insulin-like growth factor-1 receptor (IGF1R) is a tyrosine kinase receptor mediating cell growth and survival of cancer cells. We studied responses to IGF1R tyrosine kinase inhibitor NVP-AEW541 combined with conventional systemic drugs in breast cancer cell lines of different clinical subtype.

  7. Treatment of breast cancer cells by IGF1R tyrosine kinase inhibitor combined with conventional systemic drugs.

    NARCIS (Netherlands)

    Hartog, H.; Graaf, W.T.A. van der; Boezen, H.M.; Wesseling, J.

    2012-01-01

    AIM: Insulin-like growth factor-1 receptor (IGF1R) is a tyrosine kinase receptor mediating cell growth and survival of cancer cells. We studied responses to IGF1R tyrosine kinase inhibitor NVP-AEW541 combined with conventional systemic drugs in breast cancer cell lines of different clinical subtype.

  8. Ultrastructural and biochemical detection of biotin and biotinylated polypeptides in Schistosoma mansoni

    Directory of Open Access Journals (Sweden)

    Santos P.R.P.

    1997-01-01

    Full Text Available Biotinylation is proposed for the identification of surface proteins in Schistosoma mansoni using the streptavidin-HRP conjugate for the detection of labeled polypeptides. However, control samples also showed several endogenous biotinylated polypeptides. In an attempt to determine the possibility of nonspecific binding between the streptavidin-HRP conjugate and polypeptides from S. mansoni, the conjugate was blocked with biotinamidecaproate-N-hydroxysuccinimide ester (BcapNHS before biotin-streptavidin blotting. No bands were detected on the nitrocellulose sheet, demonstrating the specific recognition of biotin by the streptavidin present in the conjugate. Whole cercariae and cercarial bodies and tails showed several endogenous biotinylated polypeptides. The biotin concentration was 13 µg/190,000 cercariae. Adult worms presented less endogenous biotinylated polypeptides than cercariae. These results may be due to changes in the environment from aerobic to anaerobic conditions when cercarial bodies (schistosomula are transformed into adult worms and a decrease in CO2 production may occur. Cercariae, cercarial bodies and adult male worms were examined by transmission electron microscopy employing an avidin-colloidal gold conjugate for the detection of endogenous biotin. Gold particles were distributed mainly on the muscle fibers, but dispersed granules were observed in the tegument, mitochondria and cytosol. The discovery of endogenous biotin in S. mansoni should be investigated in order to clarify the function of this vitamin in the parasite

  9. Biotinylated chitosan-based SPIONs with potential in blood-contacting applications

    Energy Technology Data Exchange (ETDEWEB)

    Balan, Vera [Technical University ' Gh.Asachi' , Faculty of Chemical Engineering and Environmental Protection (Romania); Petrache, Ivona Andreea [' Gr.T.Popa' University of Medicine and Pharmacy, Department of Biomedical Sciences, Faculty of Medical Bioengineering (Romania); Popa, Marcel Ionel [Technical University ' Gh.Asachi' , Faculty of Chemical Engineering and Environmental Protection (Romania); Butnaru, Maria [' Gr.T.Popa' University of Medicine and Pharmacy, Department of Biomedical Sciences, Faculty of Medical Bioengineering (Romania); Barbu, Eugen; Tsibouklis, John [University of Portsmouth, School of Pharmacy and Biomedical Sciences (United Kingdom); Verestiuc, Liliana, E-mail: liliana.verestiuc@bioinginerie.ro [' Gr.T.Popa' University of Medicine and Pharmacy, Department of Biomedical Sciences, Faculty of Medical Bioengineering (Romania)

    2012-02-15

    Haemocompatible biotinylated superparamagnetic nanoparticles (size range 300-700 nm) have been obtained by coating magnetite through ionic gelation with a mixture of chitosan and sodium tripolyphosphate, followed by subsequent functionalisation with biotin. The evaluations of their magnetic properties together with haemocompatibility tests have shown that these nanoparticles exhibit the prerequisite behaviour for use in magnetic field-assisted separations within biological systems.

  10. Efficient biotinylation and single-step purification of tagged transcription factors in mammalian cells and transgenic mice

    Science.gov (United States)

    de Boer, Ernie; Rodriguez, Patrick; Bonte, Edgar; Krijgsveld, Jeroen; Katsantoni, Eleni; Heck, Albert; Grosveld, Frank; Strouboulis, John

    2003-06-01

    Proteomic approaches require simple and efficient protein purification methodologies that are amenable to high throughput. Biotinylation is an attractive approach for protein complex purification due to the very high affinity of avidin/streptavidin for biotinylated templates. Here, we describe an approach for the single-step purification of transcription factor complex(es) based on specific in vivo biotinylation. We expressed the bacterial BirA biotin ligase in mammalian cells and demonstrated very efficient biotinylation of a hematopoietic transcription factor bearing a small (23-aa) artificial peptide tag. Biotinylation of the tagged transcription factor altered neither the factor's protein interactions or DNA binding properties in vivo nor its subnuclear distribution. Using this approach, we isolated the biotin-tagged transcription factor and at least one other known interacting protein from crude nuclear extracts by direct binding to streptavidin beads. Finally, this method works efficiently in transgenic mice, thus raising the prospect of using biotinylation tagging in protein complex purification directly from animal tissues. Therefore, BirA-mediated biotinylation of tagged proteins provides the basis for the single-step purification of proteins from mammalian cells.

  11. Angiotensin II-induced migration of vascular smooth muscle cells is mediated by p38 mitogen-activated protein kinase-activated c-Src through spleen tyrosine kinase and epidermal growth factor receptor transactivation.

    Science.gov (United States)

    Mugabe, Benon E; Yaghini, Fariborz A; Song, Chi Young; Buharalioglu, Cuneyt K; Waters, Christopher M; Malik, Kafait U

    2010-01-01

    Angiotensin II (Ang II) stimulates protein synthesis by activating spleen tyrosine kinase (Syk) and DNA synthesis through epidermal growth factor receptor (EGFR) transactivation in vascular smooth muscle cells (VSMCs). This study was conducted to determine whether Syk mediates Ang II-induced migration of aortic VSMCs using a scratch wound approach. Treatment with Ang II (200 nM) for 24 h increased VSMC migration by 1.56 +/- 0.14-fold. Ang II-induced VSMC migration and Syk phosphorylation as determined by Western blot analysis were minimized by the Syk inhibitor piceatannol (10 microM) and by transfecting VSMCs with dominant-negative but not wild-type Syk plasmid. Ang II-induced VSMC migration and Syk phosphorylation were attenuated by inhibitors of c-Src [4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2)], p38 mitogen-activated protein kinase (MAPK) [4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)1H-imidazole (SB202190)], and extracellular signal-regulated kinase (ERK) 1/2 [1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio) butadiene (U0126)]. SB202190 attenuated p38 MAPK and c-Src but not ERK1/2 phosphorylation, indicating that p38 MAPK acts upstream of c-Src and Syk. The c-Src inhibitor PP2 attenuated Syk and ERK1/2 phosphorylation, suggesting that c-Src acts upstream of Syk and ERK1/2. Ang II- and epidermal growth factor (EGF)-induced VSMC migration and EGFR phosphorylation were inhibited by the EGFR blocker 4-(3-chloroanilino)-6,7-dimethoxyquinazoline (AG1478) (2 microM). Neither the Syk inhibitor piceatannol nor the dominant-negative Syk mutant altered EGF-induced cell migration or Ang II- and EGF-induced EGFR phosphorylation. The c-Src inhibitor PP2 diminished EGF-induced VSMC migration and EGFR, ERK1/2, and p38 MAPK phosphorylation. The ERK1/2 inhibitor U0126 (10 microM) attenuated EGF-induced cell migration and ERK1/2 but not EGFR phosphorylation. These data suggest that Ang II stimulates VSMC migration via p38 MAPK-activated c

  12. Safety and efficacy of everolimus in Chinese patients with metastatic renal cell carcinoma resistant to vascular endothelial growth factor receptor-tyrosine kinase inhibitor therapy: an open-label phase 1b study

    International Nuclear Information System (INIS)

    In China, there are currently no approved therapies for the treatment of metastatic renal cell carcinoma (mRCC) following progression with vascular endothelial growth factor (VEGF)-targeted agents. In the phase 3 RECORD-1 trial, the mammalian target of rapamycin (mTOR) inhibitor everolimus afforded clinical benefit with good tolerability in Western patients with mRCC whose disease had progressed despite VEGF receptor-tyrosine kinase inhibitor (VEGFr-TKI) therapy. This phase 1b study was designed to further evaluate the safety and efficacy of everolimus in VEGFr-TKI-refractory Chinese patients with mRCC. An open-label, multicenter phase 1b study enrolled Chinese patients with mRCC who were intolerant to, or progressed on, previous VEGFr-TKI therapy (N = 64). Patients received everolimus 10 mg daily until objective tumor progression (according to RECIST, version 1.0), unacceptable toxicity, death, or study discontinuation for any other reason. The final data analysis cut-off date was November 30, 2011. A total of 64 patients were included in the study. Median age was 52 years (range, 19–75 years) and 69% of patients were male. Median duration of everolimus therapy was 4.1 months (range, 0.0-16.1 months). Expected known class-effect toxicities related to mTOR inhibitor therapy were observed, including anemia (64%), hypertriglyceridemia (55%), mouth ulceration (53%), hyperglycemia (52%), hypercholesterolemia (50%), and pulmonary events (31%). Common grade 3/4 adverse events were anemia (20%), hyperglycemia (13%), increased gamma-glutamyltransferase (11%), hyponatremia (8%), dyspnea (8%), hypertriglyceridemia (6%), and lymphopenia (6%). Median PFS was 6.9 months (95% CI, 3.7-12.5 months) and the overall tumor response rate was 5% (95% CI, 1-13%). The majority of patients (61%) had stable disease as their best overall tumor response. Safety and efficacy results were comparable to those of the RECORD-1 trial. Everolimus is generally well tolerated and provides clinical

  13. Expression of proto-oncogenes in non-Hodgkin's lymphomas by in situ hybridization with biotinylated DNA probes

    International Nuclear Information System (INIS)

    Expression of six proto-oncogenes (fos, myc, myb, Ki-ras, Ha-ras, and N-ras) in 43 cases of non-Hodgkin's lymphoma was analyzed by means of in situ hybridization. Biotinylated DNA probes of the six oncogenes and those of the immunoglobulin H-chain (IgH) gene and the T cell receptor β-chain (TCRβ) gene were used. The results of in situ hybridization performed under blind conditions by IgH and TCRβ gene probes were compatible with those of typing by cell surface markers. The nuclear protein-related proto-oncogenes, fos myc, and myb, were expressed in about 70 % - 80 % of all cases regardless of phenotypes, histology or histologic grade. On the contrary, genes of the ras family were expressed in fewer cases except for the Ki-ras gene which was more frequently expressed by cases of the T cell immunophenotype with a high malignancy grade. The results of dot hybridization with RNA extracted from some cases were compatible with those of in situ hybridization, further demonstrating the specificity of in situ hybridization. (author)

  14. Identification of secreted cysteine proteases from the parasitic nematode Haemonchus contortus detected by biotinylated inhibitors

    OpenAIRE

    Yatsuda, A.P.; N. Bakker; Krijgsveld, J.; Knox, D. P.; Heck, A.J.R.; de Vries, E.

    2006-01-01

    Seven cathepsin B-like cysteine proteases (CBLs) were identified from the immunoprotective excretory-secretory products of Haemonchus contortus. Two-dimensional (2-D) zymography and biotinylated inhibitors were employed to localize active CBLs in 2-D protein gels. Mass spectrometry provided the identification of AC-4, HMCP1, HMCP2, and GCP7 as well as three novel CBLs encoded by clustered expressed sequence tags.

  15. A method for measuring binding constants using unpurified in vivo biotinylated ligands.

    Science.gov (United States)

    Pogoutse, Anastassia K; Lai, Christine Chieh-Lin; Ostan, Nicholas; Yu, Rong-Hua; Schryvers, Anthony B; Moraes, Trevor F

    2016-05-15

    Obtaining accurate kinetics and steady-state binding constants for biomolecular interactions normally requires pure and homogeneous protein preparations. Furthermore, in many cases, one of the ligands must be labeled. Over the past decade, several technologies have been introduced that allow for the measurement of kinetics constants for multiple different interactions in parallel. One such technology is bio-layer interferometry (BLI), which has been used to develop systems that can measure up to 96 biomolecular interactions simultaneously. However, despite the ever-increasing throughput of the tools available for measuring protein-protein interactions, the preparation of pure protein still remains a bottleneck in the process of producing high-quality kinetics data. Here, we show that high-quality binding data can be obtained using soluble lysate fractions containing protein that has been biotinylated in vivo using BirA and then applied to BLI sensors without further purification. Furthermore, we show that BirA ligase does not necessarily need to be co-overexpressed with the protein of interest for biotinylation of the biotin acceptor peptide to occur, suggesting that the activity of endogenous BirA in Escherichia coli is sufficient for producing enough biotinylated protein for a binding experiment. PMID:26898305

  16. Discovery of 3,5-disubstituted-1H-pyrrolo[2,3-b]pyridines as potent inhibitors of the insulin-like growth factor-1 receptor (IGF-1R) tyrosine kinase

    Energy Technology Data Exchange (ETDEWEB)

    Patnaik, Samarjit; Stevens, Kirk L.; Gerding, Roseanne; Deanda, Felix; Shotwell, J. Brad; Tang, Jun; Hamajima, Toshihiro; Nakamura, Hiroko; Leesnitzer, M. Anthony; Hassell, Anne M.; Shewchuck, Lisa M.; Kumar, Rakesh; Lei, Huangshu; Chamberlain, Stanley D.; (GSKNC); (GSKPA); (GSK)

    2009-07-23

    Exploration of the SAR around a series of 3,5-disubstituted-1H-pyrrolo[2,3-b]pyridines led to the discovery of novel pyrrolopyridine inhibitors of the IGF-1R tyrosine kinase. Several compounds demonstrated nanomolar potency in enzyme and cellular mechanistic assays.

  17. The quantitation of biotinylated compounds by a solid-phase assay using a 125I-labelled biotin derivative

    International Nuclear Information System (INIS)

    The biotin analogue biotinylglycyltyrosine has been synthesized and labelled to a specific activity of 2000 Ci/mmol with 125I. This analogue has been used in conjunction with immobilized streptavidin in an assay which detects as little as 1 fmol biotin or biotinylated molecules in solution. The determination of biotinylated insulin in a tissue extract and the quantitation of a transcription assay are given as examples. (Auth.)

  18. Yeast Ste2 receptors as tools for study of mammalian protein kinases and adaptors involved in receptor trafficking

    OpenAIRE

    2006-01-01

    Background Mammalian receptors that couple to effectors via heterotrimeric G proteins (e.g., beta 2-adrenergic receptors) and receptors with intrinsic tyrosine kinase activity (e.g., insulin and IGF-I receptors) constitute the proximal points of two dominant cell signaling pathways. Receptors coupled to G proteins can be substrates for tyrosine kinases, integrating signals from both pathways. Yeast cells, in contrast, display G protein-coupled receptors (e.g., alpha-factor pheromone receptor ...

  19. Tyrosine kinases in rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    Kobayashi Akiko

    2011-08-01

    Full Text Available Abstract Rheumatoid arthritis (RA is an inflammatory, polyarticular joint disease. A number of cellular responses are involved in the pathogenesis of rheumatoid arthritis, including activation of inflammatory cells and cytokine expression. The cellular responses involved in each of these processes depends on the specific signaling pathways that are activated; many of which include protein tyrosine kinases. These pathways include the mitogen-activated protein kinase pathway, Janus kinases/signal transducers and activators transcription pathway, spleen tyrosine kinase signaling, and the nuclear factor κ-light-chain-enhancer of activated B cells pathway. Many drugs are in development to target tyrosine kinases for the treatment of RA. Based on the number of recently published studies, this manuscript reviews the role of tyrosine kinases in the pathogenesis of RA and the potential role of kinase inhibitors as new therapeutic strategies of RA.

  20. NLRP3 tyrosine phosphorylation is controlled by protein tyrosine phosphatase PTPN22.

    Science.gov (United States)

    Spalinger, Marianne R; Kasper, Stephanie; Gottier, Claudia; Lang, Silvia; Atrott, Kirstin; Vavricka, Stephan R; Scharl, Sylvie; Gutte, Petrus M; Grütter, Markus G; Beer, Hans-Dietmar; Contassot, Emmanuel; Chan, Andrew C; Dai, Xuezhi; Rawlings, David J; Mair, Florian; Becher, Burkhard; Falk, Werner; Fried, Michael; Rogler, Gerhard; Scharl, Michael

    2016-05-01

    Inflammasomes form as the result of the intracellular presence of danger-associated molecular patterns and mediate the release of active IL-1β, which influences a variety of inflammatory responses. Excessive inflammasome activation results in severe inflammatory conditions, but physiological IL-1β secretion is necessary for intestinal homeostasis. Here, we have described a mechanism of NLRP3 inflammasome regulation by tyrosine phosphorylation of NLRP3 at Tyr861. We demonstrated that protein tyrosine phosphatase non-receptor 22 (PTPN22), variants in which are associated with chronic inflammatory disorders, dephosphorylates NLRP3 upon inflammasome induction, allowing efficient NLRP3 activation and subsequent IL-1β release. In murine models, PTPN22 deficiency resulted in pronounced colitis, increased NLRP3 phosphorylation, but reduced levels of mature IL-1β. Conversely, patients with inflammatory bowel disease (IBD) that carried an autoimmunity-associated PTPN22 variant had increased IL-1β levels. Together, our results identify tyrosine phosphorylation as an important regulatory mechanism for NLRP3 that prevents aberrant inflammasome activation. PMID:27043286

  1. Identification of Interactions in the NMD Complex Using Proximity-Dependent Biotinylation (BioID)

    OpenAIRE

    Christoph Schweingruber; Paolo Soffientini; Marc-David Ruepp; Angela Bachi; Oliver Mühlemann

    2016-01-01

    Proximity-dependent trans-biotinylation by the Escherichia coli biotin ligase BirA mutant R118G (BirA*) allows stringent streptavidin affinity purification of proximal proteins. This so-called BioID method provides an alternative to the widely used co-immunoprecipitation (co-IP) to identify protein-protein interactions. Here, we used BioID, on its own and combined with co-IP, to identify proteins involved in nonsense-mediated mRNA decay (NMD), a post-transcriptional mRNA turnover pathway that...

  2. A Surface Biotinylation Strategy for Reproducible Plasma Membrane Protein Purification and Tracking of Genetic and Drug-Induced Alterations.

    Science.gov (United States)

    Hörmann, Katrin; Stukalov, Alexey; Müller, André C; Heinz, Leonhard X; Superti-Furga, Giulio; Colinge, Jacques; Bennett, Keiryn L

    2016-02-01

    Plasma membrane (PM) proteins contribute to the identity of a cell, mediate contact and communication, and account for more than two-thirds of known drug targets.1-8 In the past years, several protocols for the proteomic profiling of PM proteins have been described. Nevertheless, comparative analyses have mainly focused on different variations of one approach.9-11 We compared sulfo-NHS-SS-biotinylation, aminooxy-biotinylation, and surface coating with silica beads to isolate PM proteins for subsequent analysis by one-dimensional gel-free liquid chromatography mass spectrometry. Absolute and relative numbers of PM proteins and reproducibility parameters on a qualitative and quantitative level were assessed. Sulfo-NHS-SS-biotinylation outperformed aminooxy-biotinylation and surface coating using silica beads for most of the monitored criteria. We further simplified this procedure by a competitive biotin elution strategy achieving an average PM annotated protein fraction of 54% (347 proteins). Computational analysis using additional databases and prediction tools revealed that in total over 90% of the purified proteins were associated with the PM, mostly as interactors. The modified sulfo-NHS-SS-biotinylation protocol was validated by tracking changes in the plasma membrane proteome composition induced by genetic alteration and drug treatment. Glycosylphosphatidylinositol (GPI)-anchored proteins were depleted in PM purifications from cells deficient in the GPI transamidase component PIGS, and treatment of cells with tunicamycin significantly reduced the abundance of N-glycoproteins in surface purifications. PMID:26699813

  3. Protein tyrosine phosphatases expression during development of mouse superior colliculus

    OpenAIRE

    Reinhard, Jacqueline; Horvat-Bröcker, Andrea; Illes, Sebastian; Zaremba, Angelika; Knyazev, Piotr; Ullrich, Axel; Faissner, Andreas

    2009-01-01

    Protein tyrosine phosphatases (PTPs) are key regulators of different processes during development of the central nervous system. However, expression patterns and potential roles of PTPs in the developing superior colliculus remain poorly investigated. In this study, a degenerate primer-based reverse transcription-polymerase chain reaction (RT-PCR) approach was used to isolate seven different intracellular PTPs and nine different receptor-type PTPs (RPTPs) from embryonic E15 mouse superior col...

  4. A vesicle surface tyrosine kinase regulates phagosome maturation

    OpenAIRE

    Fang, Jun; Brzostowski, Joseph A.; Ou, Stephen; Isik, Nilgun; Nair, Vinod; Jin, Tian

    2007-01-01

    Phagocytosis is crucial for host defense against microbial pathogens and for obtaining nutrients in Dictyostelium discoideum. Phagocytosed particles are delivered via a complex route from phagosomes to lysosomes for degradation, but the molecular mechanisms involved in the phagosome maturation process are not well understood. Here, we identify a novel vesicle-associated receptor tyrosine kinase-like protein, VSK3, in D. discoideum. We demonstrate how VSK3 is involved in phagosome maturation. ...

  5. Involvement of the Tyrosine Kinase Fer in Cell Adhesion

    OpenAIRE

    Rosato, Roberto; Veltmaat, Jacqueline M.; Groffen, John; Heisterkamp, Nora

    1998-01-01

    The Fer protein belongs to the fes/fps family of nontransmembrane receptor tyrosine kinases. Lack of success in attempts to establish a permanent cell line overexpressing it at significant levels suggested a strong negative selection against too much Fer protein and pointed to a critical cellular function for Fer. Using a tetracycline-regulatable expression system, overexpression of Fer in embryonic fibroblasts was shown to evoke a massive rounding up, and the subsequent detachment of the cel...

  6. Physical and functional association of the cbl protooncogen product with an src-family protein tyrosine kinase, p53/56lyn, in the B cell antigen receptor-mediated signaling

    OpenAIRE

    1996-01-01

    To identify novel signal transducers involved in signaling mediated by the Src-family protein tyrosine kinases (PTKs), we used a yeast two- hybrid system with a probe corresponding to the regulatory region of p56lyn, a member of Src-family PTKs. One of the isolated clones contained the COOH-terminal 470 amino acid residues of p120c-cbl, the product of the cellular homologue of the v-cbl retroviral oncogene. p120c-cbl is a cytoplasmic protein with nuclear protein-like motifs. Here we show in v...

  7. Three-step tumor imaging with biotinylated monoclonal antibody, streptavidin and 111In-DTPA-biotin

    International Nuclear Information System (INIS)

    The purpose of this study was to test the three-step targeting of tumors in mice using biotinylated antibody, streptavidin and radiolabeled biotin. Nude mice bearing subcutaneous LS180 human colon cancer xenografts were intravenously administered with 200 μg of the biotinylated anti-Tn monoclonal antibody MLS128, and 2 days later they got intravenous injection of 50 μg of streptavidin. They were intravenously injected 1, 4 or 7 days later with 0.5 μg of 111In-diethylenetriamine pentaacetic acid (DTPA)-biotin. The tumor uptake, determined 2 h later, was 1.4, 0.5 and 0.6% injected dose/gram of tissue (ID/g), respectively, and the blood radioactivity was 1.0, 0.2 and 0.2% ID/g, respectively. When the interval between the streptavidin and radiolabeled biotin injections was prolonged from 1 day to 7 days, the tumor-to-blood ratio 2 h after injection of 111In-labeled biotin increased from 1.5 to 4.0. Clear tumor images were obtained as early as 2 h after injection of radiolabeled biotin. In conclusion, these preliminary data suggested that the three-step method using the streptavidin-biotin system would be applicable in an experimental mouse tumor model and provides images of tumors rapidly and clearly after injection of radiolabeled biotin

  8. Optical tweezing electrophoresis of single biotinylated colloidal particles for avidin concentration measurement

    Science.gov (United States)

    Brans, Toon; Strubbe, Filip; Schreuer, Caspar; Neyts, Kristiaan; Beunis, Filip

    2015-06-01

    We present a novel approach for label-free concentration measurement of a specific protein in a solution. The technique combines optical tweezers and microelectrophoresis to establish the electrophoretic mobility of a single microparticle suspended in the solution. From this mobility measurement, the amount of adsorbed protein on the particle is derived. Using this method, we determine the concentration of avidin in a buffer solution. After calibration of the setup, which accounts for electro-osmotic flow in the measurement device, the mobilities of both bare and biotinylated microspheres are measured as a function of the avidin concentration in the mixture. Two types of surface adsorption are identified: the biotinylated particles show specific adsorption, resulting from the binding of avidin molecules with biotin, at low avidin concentrations (below 0.04 μg/ml) while at concentrations of several μg/ml non-specific on both types of particles is observed. These two adsorption mechanisms are incorporated in a theoretical model describing the relation between the measured mobility and the avidin concentration in the mixture. This model describes the electrophoretic mobility of these particles accurately over four orders of magnitude of the avidin concentration.

  9. Biotinylated polyalkylthiophene thin films and monolayers that specifically incorporate phycobiliproteins: toward smart materials

    Science.gov (United States)

    Ayyagari, Madhu S. R.; Pande, Rajiv; Lim, Jeong O.; Kamath, Manohar; Beladakere, Nagendra; Gao, Harry H.; Marx, Kenneth A.; Tripathy, Sukant K.; Kumar, Jayant; Samuelson, Lynne A.; Akkara, Joseph A.; Kaplan, David L.

    1994-05-01

    We are investigating thin film and monolayer systems that involve conjugated conducting polymers and specific biological macromolecules. One class of conducting polymers, polyalkylthiophenes, are derivatized with biotin. These biotinylated polymers form the basis for a generic cassette system of attachment for any biological molecule through biotinylation or interaction with streptavidin. The high affinity of the biotin-streptavidin system, used in sequential steps, forms the basis of the cassette method. We have formed both monolayers and thin films (a few nanometers) of the cassette assembly in which phycobiliproteins are incorporated. We are investigating the optical signal transduction properties of specific phycobiliproteins (phycoerythrin, phycocyanin and allophycocyanain) using the cassette system on the inner surface of glass capillaries and on optical fiber surfaces. Phycobiliprotein photocurrent signals in conducting polymer matrices on microelectrodes are also being investigated. Our aim is to integrate the signal transduction mechanisms of the phycobiliproteins within monolayers or thin films of the conducting polymers to create biosensors and related smart materials for applications in biomedicine and biotechnology.

  10. Identification of Interactions in the NMD Complex Using Proximity-Dependent Biotinylation (BioID).

    Science.gov (United States)

    Schweingruber, Christoph; Soffientini, Paolo; Ruepp, Marc-David; Bachi, Angela; Mühlemann, Oliver

    2016-01-01

    Proximity-dependent trans-biotinylation by the Escherichia coli biotin ligase BirA mutant R118G (BirA*) allows stringent streptavidin affinity purification of proximal proteins. This so-called BioID method provides an alternative to the widely used co-immunoprecipitation (co-IP) to identify protein-protein interactions. Here, we used BioID, on its own and combined with co-IP, to identify proteins involved in nonsense-mediated mRNA decay (NMD), a post-transcriptional mRNA turnover pathway that targets mRNAs that fail to terminate translation properly. In particular, we expressed BirA* fused to the well characterized NMD factors UPF1, UPF2 and SMG5 and detected by liquid chromatography-coupled tandem mass spectrometry (LC-MS/MS) the streptavidin-purified biotinylated proteins. While the identified already known interactors confirmed the usefulness of BioID, we also found new potentially important interactors that have escaped previous detection by co-IP, presumably because they associate only weakly and/or very transiently with the NMD machinery. Our results suggest that SMG5 only transiently contacts the UPF1-UPF2-UPF3 complex and that it provides a physical link to the decapping complex. In addition, BioID revealed among others CRKL and EIF4A2 as putative novel transient interactors with NMD factors, but whether or not they have a function in NMD remains to be elucidated. PMID:26934103

  11. Bacterial Protein-Tyrosine Kinases

    DEFF Research Database (Denmark)

    Shi, Lei; Kobir, Ahasanul; Jers, Carsten;

    2010-01-01

    Bacteria and Eukarya share essentially the same family of protein-serine/threonine kinases, also known as the Hanks-type kinases. However, when it comes to protein-tyrosine phosphorylation, bacteria seem to have gone their own way. Bacterial protein-tyrosine kinases (BY-kinases) are bacterial...... enzymes that are unique in exploiting the ATP/GTP-binding Walker motif to catalyze phosphorylation of protein tyrosine residues. Characterized for the first time only a decade ago, BY-kinases have now come to the fore. Important regulatory roles have been linked with these enzymes, via their involvement...... in exopolysaccharide production, virulence, DNA metabolism, stress response and other key functions of the bacterial cell. BY-kinases act through autophosphorylation (mainly in exopolysaccharide production) and phosphorylation of other proteins, which have in most cases been shown to be activated by...

  12. Traditional Chinese medicinal herbs combined with epidermal growth factor receptor tyrosine kinase inhibitor for advanced non-small cell lung cancer:a systematic review and meta-analysis

    Institute of Scientific and Technical Information of China (English)

    Zhong-liang Liu; Wei-rong Zhu; Wen-chao Zhou; Hai-feng Ying; Lan Zheng; Yuan-biao Guo; Jing-xian Chen; Xiao-heng Shen

    2014-01-01

    BACKGROUND: Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) targeted treatment has been a standard therapy for advanced non-small cell lung cancer (NSCLC), but it is not tolerated well by all patients. In China, some studies have reported that traditional Chinese medicinal herbs (TCMHs) may increase efifcacy and reduce toxicity when combined with EGFR-TKI, but outside of China few studies of this kind have been attempted. OBJECTIVE:This study is intended to systematically review the existing clinical evidence on TCMHs combined with EGFR-TKI for treatment of advanced NSCLC. SEARCH STRATEGY:PubMed, the Cochrane Library, the Excerpta Medica Database (EMBASE), the China BioMedical Literature (CBM), and the China National Knowledge Infrastructure (CNKI) and web site of the American Society of Clinical Oncology (ASCO), the European Society for Medical Oncology (ESMO), the World Conference of Lung Cancer (WCLC) were searched; the search included all documents published in English or Chinese before October 2013. INCLUSION CRITERIA:We selected randomized controlled trials based on speciifc criteria, the most important of which was that a TCMH plus EGFR-TKI treatment group was compared with an EGFR-TKI control group in patients with advanced NSCLC. DATA EXTRACTION AND ANALYSIS: The modiifed Jadad scale was used to assess the quality of studies. For each included study, patient characteristics, treatment details, therapeutic approach and clinical outcomes were collected on a standardized form. When disagreements on study inclusion or data extracted from a study emerged, the consensus of all coauthors provided the resolution. The clinical outcome metrics consisted of objective response rate (ORR; complete response + partial response divided by the total number of patients), disease control rate (DCR; complete response + partial response + no change divided by the total number of patients), survival rate, improved or stabilized Karnofsky performance status

  13. The tyrosine phosphatase STEP: implications in schizophrenia and the molecular mechanism underlying antipsychotic medications

    OpenAIRE

    Carty, N C; Xu, J.; Kurup, P; Brouillette, J.; Goebel-Goody, S M; Austin, D.R.; Yuan, P.; Chen, G.; Correa, P R; Haroutunian, V; Pittenger, C; Lombroso, P.J.

    2012-01-01

    Glutamatergic signaling through N-methyl-D-aspartate receptors (NMDARs) is required for synaptic plasticity. Disruptions in glutamatergic signaling are proposed to contribute to the behavioral and cognitive deficits observed in schizophrenia (SZ). One possible source of compromised glutamatergic function in SZ is decreased surface expression of GluN2B-containing NMDARs. STEP61 is a brain-enriched protein tyrosine phosphatase that dephosphorylates a regulatory tyrosine on GluN2B, thereby promo...

  14. Ultrasensitive immuno-detection using viral nanoparticles with modular assembly using genetically-directed biotinylation

    Science.gov (United States)

    Litvinov, Julia; Hagström, Anna E. V.; Lopez, Yubitza; Adhikari, Meenu; Kourentzi, Katerina; Strych, Ulrich; Monzon, Federico A.; Foster, William; Cagle, Philip T.; Willson, Richard C.

    2014-01-01

    We report a novel, modular approach to immuno-detection based on antibody recognition and PCR read-out that employs antibody-conjugated bacteriophage, easily-manipulated nonpathogenic viruses, as affinity agents. Our platform employs phage genetically tagged for in vivo biotinylation during phage maturation that can easily be linked, through avidin, to any biotinylatable affinity agent, including full-length antibodies, peptides, lectins or aptamers. The presence of analyte is reported with high sensitivity through real-time PCR. This approach avoids the need to clone antibody-encoding DNA fragments, allows the use of full-length, high affinity antibodies and, by having DNA reporters naturally encapsulated inside the bacteriophage, greatly reduces nonspecific binding of DNA. We validate the efficacy of this new approach through the detection of VEGF (Vascular Endothelial Growth Factor), a known angiogenic cancer biomarker protein, at attomolar concentrations in bronchoalveolar lavage (BAL) fluid. PMID:24930095

  15. Synthesis and in Vitro evaluation of ''1''8''8Re-biotinyl-hydrazino-etda

    International Nuclear Information System (INIS)

    Pretargeting strategies have overcome many drawbacks associated with the use of directly labelled MoAbs in the diagnosis / treatment of various solid tumors. In particular the avidin-biotin system has received much attention due to extremely high affinity between avidin and biotin. An EDTA derivative of biotin has been synthesized (yield-35%). In order or label biotin derivative (biotinyl-hydrazino-EDTA) , stannous ion was used to reduce ''1''8''8ReO4 (VII) to lower oxidation state and weak chelating agent glucoheptonate as stabilizer and trans chelating agent. Thin layer chromatography and high performance liquid chromatography techniques were employed to monitor the radiolabeling efficiency. The radiolabeling yield of ''1''8''8Re-EDTAB1 was >95%. The radiolabeled product was found to bind to avidin (70-80%), thereby demonstrating retention of its biological integrity

  16. Two-step tumour targetting in ovarian cancer patients using biotinylated monoclonal antibodies and radioactive streptavidin

    International Nuclear Information System (INIS)

    A new method for intraperitoneal tumour targetting in ovarian cancer using biotinylated monoclonal antibodies (MoAb) and radioactive streptavidin is described. Fifteen patients with histologically documented ovarian carcinoma were injected intraperitoneally with 2 mg of biotinylated MOAb MOv18, followed 3-5 days later by 100-150 μg of indium-111 streptavidin, at the specific activity of 280-370 MB q/mg in 500 ml of normal saline. No toxicity was observed. Tumours were imaged from 2 to 48 h after radioactivity injection by recording both planar and single photon emission tomography (SPET) data. All patients underwent surgery 1-8 days later (mean 3 days) after scanning. The resected tumour and normal tissue radioactivity were measured. On the day of surgery, the tumour to normal tissue ratio was 9:1 (range 3:1-30:1) and 45:1 (range 12:1-120:1) for intra- and extraperitoneal samples, respectively. The mean tumor to blood ratio was 14:1 (range 4:1-30:1). The injected dose (i.d.) per gram of tumour was 0.112 (range 0.01-0.3) for recurrences and 0.05 for primary tumour (range 0.005-0.2). Over 24-48 h 14% i.d. (range 8-18% i.d.) was found in the urine, 14% i.d. (range 6-29% i.d.) in the blood and 63% i.d. (range 56-70% i.d.) was still in the peritoneal cavity. These preliminary clinical data suggest that this two-step strategy may be superior to the conventional approach (radiolabelled antibodies) for intraperitoneal radioimmunolocalization and radioimmunotherapy of ovarian cancer. (orig.)

  17. DMPD: Bruton's tyrosine kinase (Btk)-the critical tyrosine kinase in LPS signalling? [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15081522 Bruton's tyrosine kinase (Btk)-the critical tyrosine kinase in LPS signall...ruton's tyrosine kinase (Btk)-the critical tyrosine kinase in LPS signalling? PubmedID 15081522 Title Bruton...'s tyrosine kinase (Btk)-the critical tyrosine kinase in LPS signalling? Authors

  18. Ibrutinib: a first in class covalent inhibitor of Bruton’s tyrosine kinase

    OpenAIRE

    Davids, Matthew S.; Brown, Jennifer R

    2014-01-01

    Ibrutinib (formerly PCI-32765) is a potent, covalent inhibitor of Bruton’s tyrosine kinase, a kinase downstream of the B-cell receptor that is critical for B-cell survival and proliferation. In preclinical studies, ibrutinib bound to Bruton’s tyrosine kinase with high affinity, leading to inhibition of B-cell receptor signaling, decreased B-cell activation and induction of apoptosis. In clinical studies, ibrutinib has been well-tolerated and has demonstrated profound anti-tumor activity in a ...

  19. XAFS of human tyrosine hydroxylase

    Science.gov (United States)

    Meyer, W.; Haavik, J.; Winkler, H.; Trautwein, A. X.; Nolting, H.-F.

    1995-02-01

    Tyrosine hydroxylase (TH) catalyses the rate-limiting step (hydroxylation of tyrosine to form dihydroxyphenylalanine) in the biosynthetic pathway leading to the catecholamines dopamine, noradrenaline and adrenaline. The human enzyme (hTH) is present in four isoforms, generated by splicing of pre-mRNA. The purified apoenzyme (metal free) binds stoichiometric amounts of iron. The incorporation of Fe(II) results in a rapid and up to 40-fold increase of activity [1]. Besides the coordination of the metal centers in native enzyme we studied the purported inhibition of TH by its immediate products. So we analysed Fe-hTH isoform 1 native as well as oxidized with dopamine and Co-hTH isoform 2.

  20. receptores

    Directory of Open Access Journals (Sweden)

    Salete Regina Daronco Benetti

    2006-01-01

    Full Text Available Se trata de un estudio etnográfico, que tuvo lo objetivo de interpretar el sistema de conocimiento y del significado atribuidos a la sangre referente a la transfusión sanguínea por los donadores y receptores de un banco de sangre. Para la colecta de las informaciones se observaron los participantes y la entrevista etnográfica se realizó el análisis de dominio, taxonómicos y temáticos. Los dominios culturales fueron: la sangre es vida: fuente de vida y alimento valioso; creencias religiosas: fuentes simbólicas de apoyos; donación sanguínea: un gesto colaborador que exige cuidarse, gratifica y trae felicidad; donación sanguínea: fuente simbólica de inseguridad; estar enfermo es una condición para realizar transfusión sanguínea; transfusión sanguínea: esperanza de vida; Creencias populares: transfusión sanguínea como riesgo para la salud; donadores de sangre: personas benditas; donar y recibir sangre: como significado de felicidad. Temática: “líquido precioso que origina, sostiene, modifica la vida, provoca miedo e inseguridad”.

  1. Tyrosine Recombinase Retrotransposons and Transposons.

    Science.gov (United States)

    Poulter, Russell T M; Butler, Margi I

    2015-04-01

    Retrotransposons carrying tyrosine recombinases (YR) are widespread in eukaryotes. The first described tyrosine recombinase mobile element, DIRS1, is a retroelement from the slime mold Dictyostelium discoideum. The YR elements are bordered by terminal repeats related to their replication via free circular dsDNA intermediates. Site-specific recombination is believed to integrate the circle without creating duplications of the target sites. Recently a large number of YR retrotransposons have been described, including elements from fungi (mucorales and basidiomycetes), plants (green algae) and a wide range of animals including nematodes, insects, sea urchins, fish, amphibia and reptiles. YR retrotransposons can be divided into three major groups: the DIRS elements, PAT-like and the Ngaro elements. The three groups form distinct clades on phylogenetic trees based on alignments of reverse transcriptase/ribonuclease H (RT/RH) and YR sequences, and also having some structural distinctions. A group of eukaryote DNA transposons, cryptons, also carry tyrosine recombinases. These DNA transposons do not encode a reverse transcriptase. They have been detected in several pathogenic fungi and oomycetes. Sequence comparisons suggest that the crypton YRs are related to those of the YR retrotransposons. We suggest that the YR retrotransposons arose from the combination of a crypton-like YR DNA transposon and the RT/RH encoding sequence of a retrotransposon. This acquisition must have occurred at a very early point in the evolution of eukaryotes. PMID:26104693

  2. Expression of tetraspan protein CD63 activates protein-tyrosine kinase (PTK) and enhances the PTK-induced inhibition of ROMK channels.

    NARCIS (Netherlands)

    Lin, D.; Kamsteeg, E.J.; Zhang, Y.; Jin, Y.; Sterling, H.; Yue, P.; Roos, M.; Duffield, A.; Spencer, J.; Caplan, M.; Wang, W.H.

    2008-01-01

    In the present study, we tested the role of CD63 in regulating ROMK1 channels by protein-tyrosine kinase (PTK). Immunocytochemical staining shows that CD63 and receptor-linked tyrosine phosphatase alpha (RPTPalpha) are expressed in the cortical collecting duct and outer medulla collecting duct. Immu

  3. In vivo Biotinylation Based Method for the Study of Protein-Protein Proximity in Eukaryotic Cells

    Directory of Open Access Journals (Sweden)

    Arman Kulyyassov

    2014-01-01

    Full Text Available Introduction: The spatiotemporal order plays an important role in cell functioning and is affected in many pathologies such as cancer and neurodegenerative diseases. One of the ultimate goals of molecular biology is reconstruction of the spatiotemporal structure of a living cell at the molecular level. This task includes determination of proximities between different molecular components in the cell and monitoring their time- and physiological state-dependent changes. In many cases, proximity between macromolecules arises due to their interactions; however, the contribution of dynamic self-organization in generation of spatiotemporal order is emerging as another viable possibility. Specifically, in proteomics, this implies that the detection of protein-protein proximity is a more general task than gaining information about physical interactions between proteins, as it could detail aspects of spatial order in vivo that are challenging to reconstitute in binding experiments in vitro. Methods: In this work, we have developed a method of monitoring protein-protein proximity in vivo. For this purpose, the BirA was fused to one of the interaction partners, whereas the BAP was modified to make the detection of its biotinylation possible by mass spectrometry. Results: Using several experimental systems, we showed that the biotinylation is interaction dependent. In addition, we demonstrated that BAP domains with different primary amino acid structures and thus with different molecular weights can be used in the same experiment, providing the possibility of multiplexing. Alternatively to the changes in primary amino acid structure, the stable isotope format can also be used, providing another way to perform multiplexing experiments. Finally, we also demonstrated that our system could help to overcome another limitation of current methodologies to detect protein-protein proximity. For example, one can follow the state of a protein of interest at a defined

  4. Structure-based network analysis of activation mechanisms in the ErbB family of receptor tyrosine kinases: the regulatory spine residues are global mediators of structural stability and allosteric interactions.

    Directory of Open Access Journals (Sweden)

    Kevin A James

    Full Text Available The ErbB protein tyrosine kinases are among the most important cell signaling families and mutation-induced modulation of their activity is associated with diverse functions in biological networks and human disease. We have combined molecular dynamics simulations of the ErbB kinases with the protein structure network modeling to characterize the reorganization of the residue interaction networks during conformational equilibrium changes in the normal and oncogenic forms. Structural stability and network analyses have identified local communities integrated around high centrality sites that correspond to the regulatory spine residues. This analysis has provided a quantitative insight to the mechanism of mutation-induced "superacceptor" activity in oncogenic EGFR dimers. We have found that kinase activation may be determined by allosteric interactions between modules of structurally stable residues that synchronize the dynamics in the nucleotide binding site and the αC-helix with the collective motions of the integrating αF-helix and the substrate binding site. The results of this study have pointed to a central role of the conserved His-Arg-Asp (HRD motif in the catalytic loop and the Asp-Phe-Gly (DFG motif as key mediators of structural stability and allosteric communications in the ErbB kinases. We have determined that residues that are indispensable for kinase regulation and catalysis often corresponded to the high centrality nodes within the protein structure network and could be distinguished by their unique network signatures. The optimal communication pathways are also controlled by these nodes and may ensure efficient allosteric signaling in the functional kinase state. Structure-based network analysis has quantified subtle effects of ATP binding on conformational dynamics and stability of the EGFR structures. Consistent with the NMR studies, we have found that nucleotide-induced modulation of the residue interaction networks is not

  5. The Complex of Ciliary Neurotrophic Factor-Ciliary Neurotrophic Factor Receptor α Up-Regulates Connexin43 and Intercellular Coupling in Astrocytes via the Janus Tyrosine Kinase/Signal Transducer and Activator of Transcription PathwayD⃞

    OpenAIRE

    Ozog, Mark A.; Bernier, Suzanne M; Bates, Dave C.; Chatterjee, Bishwanath; Lo, Cecilia W.; Naus, Christian C.G.

    2004-01-01

    Cytokines regulate numerous cell processes, including connexin expression and gap junctional coupling. In this study, we examined the effect of ciliary neurotrophic factor (CNTF) on connexin43 (Cx43) expression and intercellular coupling in astrocytes. Murine cortical astrocytes matured in vitro were treated with CNTF (20 ng/ml), soluble ciliary neurotrophic factor receptor α (CNTFRα) (200 ng/ml), or CNTF-CNTFRα. Although CNTF and CNTFRα alone had no effect on Cx43 expression, the heterodimer...

  6. Expressions of nerve growth factor and its high-affinity receptor, tyrosine kinase A, as well as low-affinity common receptor, p75 neurotrophin receptor, in the lesions of lichen planus and their clinical significance%神经生长因子及其高亲和受体酪氨酸激酶、低亲和公共受体p75NTR在扁平苔藓皮损中的表达及意义

    Institute of Scientific and Technical Information of China (English)

    钱悦; 陈思远; 黄长征; 冯爱平; 褚淑娟

    2014-01-01

    Objective To detect the expressions of nerve growth factor (NGF) and its receptors tyrosine kinase A (TrkA) as well as p75 neurotrophin receptor (p75NTR) in the lesions of lichen planus.Methods Biopsy specimens were collected from the lesions of 32 patients with lichen planus and normal skin of 12 healthy human controls and subjected to paraffin embedding.Immunohistochemical avidin-biotin complex (ABC) method was used to detect the expressions of NGF,TrkA and p75NTR.Results NGF and TrkA,which were located in the cytoplasm of keratinocytes,were strongly or moderately expressed in the lesional skin specimens,but absent or weakly expressed in the normal skin specimens (both P < 0.01).No significant differences were observed in the expression of p75NTR between the lesional and normal skin specimens,or in the expressions of NGF,TrkA or p75NTR among specimens from patients in different age groups,patients of different gender or lesions at different sites (all P > 0.05).There was a positive correlation between the expression of NGF and TrkA in the lesions of lichen planus (R2 =0.535,P < 0.01).Conclusion NGF may play a certain role in the development of lichen planus via its highaffinity receptor TrkA.%目的 检测神经生长因子(NGF)及其受体TrkA、p75NTR在扁平苔藓皮损中的表达.方法 应用免疫组化ABC法检测32例扁平苔藓皮损和12例健康人皮肤石蜡标本NGF及其受体TrkA、p75NTR表达状况.结果 NGF及TrkA在32例扁平苔藓皮损表皮角质形成细胞中均有不同程度的表达(++~+++),表达部位为细胞质,高于健康人皮肤NGF(-~+)及TrkA(-~+)的表达,两组间差异均有统计学意义(P<0.01);而p75NTR的表达两组差异无统计学意义.扁平苔藓皮损中NGF与TrkA表达呈正相关(R2=0.535,P< 0.01).NGF及其受体TrkA、p75NTR在扁平苔藓不同发病年龄、部位以及不同性别患者角质形成细胞中的表达差异均无统计学意义.结论 NGF通过其高亲和受体TrkA在

  7. Blood group glycolipids as epithelial cell receptors for Candida albicans.

    OpenAIRE

    Cameron, B J; Douglas, L J

    1996-01-01

    The role of glycosphingolipids as possible epithelial cell receptors for Candida albicans was examined by investigating the binding of biotinylated yeasts to lipids extracted from human buccal epithelial cells and separated on thin-layer chromatograms. Binding was visualized by the addition of 125I-streptavidin followed by autoradiography. Five C. albicans strains thought from earlier work to have a requirement for fucose-containing receptors all bound to the same three components in the lipi...

  8. Development of a specific biotinylated DNA probe for the detection of Renibacterium salmoninarum.

    Science.gov (United States)

    Hariharan, H; Qian, B; Despres, B; Kibenge, F S; Heaney, S B; Rainnie, D J

    1995-10-01

    A specific DNA probe for the identification of Renibacterium salmoninarum, the causative agent of bacterial kidney disease (BKD), was developed from one of 3 clones pRS47, pRS49, and pRS26 of 5.1 kb, 5.3 kb, and 11.3 kb, respectively. The biotinylated pRS47/BamHI insert probe was tested on 3 dilutions of DNA extracted from 3 strains of R. salmoninarum and from 1 strain each of Arthrobacter protophormiae, Aeromonas salmonicida, Corynebacterium aquaticum, Carnobacterium piscicola, Listonella anguillarum, Micrococcus luteus, Pseudomonas fluorescens, Vibrio ordalii, and Yersinia ruckeri. In a dot blot assay, this probe hybridized only with the DNA from the R. salmoninarum strains. When used on kidney samples from fish challenged with R. salmoninarum, the dot blot hybridization assay with the probe was found to be as sensitive as culture. In a fluorescent antibody test, samples that were negative in culture and dot blot hybridization showed no more than one fluorescing cell in 50 microscopic fields examined. This DNA probe, therefore, has the potential for use in the diagnosis of BKD of fish. PMID:8548693

  9. Expression of protein-tyrosine phosphatases in the major insulin target tissues

    DEFF Research Database (Denmark)

    Norris, K; Norris, F; Kono, D H;

    1997-01-01

    Protein-tyrosine phosphatases (PTPs) are key regulators of the insulin receptor signal transduction pathway. We have performed a detailed analysis of PTP expression in the major human insulin target tissues or cells (liver, adipose tissue, skeletal muscle and endothelial cells). To obtain a repre...

  10. Electrophoretic behavior of streptavidin complexed to a biotinylated probe : A functional screening assay for biotin-binding proteins

    OpenAIRE

    Humbert, Nicolas; Zocchi, Andrea; Ward, Thomas R.

    2006-01-01

    The biotin-binding protein streptavidin exhibits a high stability against thermal denaturation, especially when complexed to biotin. Herein we show that, in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), streptavidin is stabilized at high temperature in the presence of biotinylated fluorescent probes, such as biotin-4-fluorescein, which is incorporated within the binding pocket. In nondenaturing SDS-PAGE, streptavidin is detectable when complexed with biotin-4-fluoresce...

  11. Production and characterization of a biotinylated single-chain variable fragment antibody for detection of parathion-methyl.

    Science.gov (United States)

    Wang, Huimin; Zhao, Fengchun; Han, Xiao; Yang, Zhengyou

    2016-10-01

    In this article, we reported the development of a biotinylated single-chain variable fragment (scFv) antibody based indirect competitive enzyme-linked immunosorbent assay (IC-ELISA) for parathion-methyl (PM) detection. Firstly, a phage display library was generated using a pre-immunized BALB/C mouse against a specific hapten of PM. After four rounds of panning, the scFv gene fragments were transferred into a secreted expression vector. Then, the scFv antibodies were secreted expressed and screened by IC-ELISA against PM. The selected scFv antibody was fused with a biotin acceptor domain (BAD) and inserted into pET-28a(+) vector for high-level expression in Escherichia coli BL2 (DE3). After optimizing expression conditions, the scFv-BAD antibody was expressed as a soluble protein and biotinylated in vitro by the E. coli biotin ligase (BirA). Subsequently, the biotinylated scFv-BAD antibody was purified with a high yield of 59.2 ± 3.7 mg/L of culture, and was characterized by SDS-PAGE and western blotting. Finally, based on the biotinylated scFv-BAD, a sensitive IC-ELISA for detection of PM was developed, and the 50% inhibition value (IC50) of PM was determined as 14.5 ng/mL, with a limit of detection (LOD, IC10) of 0.9 ng/mL. Cross-reactivity (CR) studies revealed that the scFv antibody showed desirable specificity for PM. PMID:27181246

  12. Production of Genetically Engineered Biotinylated Interleukin-2 and Its Application in a Rapid Nonradioactive Assay for T-Cell Activation

    OpenAIRE

    Jordan, Robert A.; Preissler, Mark T.; Banas, Jeffrey A.; Gosselin, Edmund J.

    2003-01-01

    The development of reliable assay systems that can measure lymphocyte activation in vitro has been a major goal of immunodiagnostics. Traditionally, tritiated thymidine incorporation has been used to monitor T-cell activation. Other methods include enzyme-linked immunosorbent assay (ELISA), enzyme-linked immunospot assay, and colorimetric assays. We have established a lymphocyte activation assay that utilizes fluorescein isothiocyanate (FITC)-streptavidin bound to recombinant biotinylated hum...

  13. Dermatologic Toxicities from Monoclonal Antibodies and Tyrosine Kinase Inhibitors against EGFR: Pathophysiology and Management

    OpenAIRE

    Shaad E. Abdullah; Missak Haigentz; Bilal Piperdi

    2012-01-01

    Epidermal growth factor receptor (EGFR) inhibition has now been well established as an effective treatment for various cancers. The EGFR belongs to the ErbB family of tyrosine kinase receptors which regulate tumor cell differentiation, survival and proliferation. Activation of EGFR drives tumorigenesis in lung, head and neck, colorectal and pancreatic cancers. Irrespective of the type of cancer being treated and the mechanism by which tumor EGFR drives tumorigenesis, the major side effect of ...

  14. Ligand-independent tyrosine kinase signalling in RTH 149 trout hepatoma cells: comparison among heavy metals and pro-oxidants.

    Science.gov (United States)

    Burlando, Bruno; Magnelli, Valeria; Panfoli, Isabella; Berti, Elena; Viarengo, Aldo

    2003-01-01

    Tyrosine phosphorylation depends on the activity of receptor and non-receptor tyrosine kinases and promote cell growth, differentiation and apoptosis. Different stressors are known to stimulate tyrosine kinase activities and this could explain a wide spectrum of effects that these agents produce on different organisms. We studied the effects of heavy metals and pro-oxidants on tyrosine kinase signalling in trout hepatoma cells (RTH 149) by Western immunoblotting. Use of antiphosphotyrosine showed that Hg(2+) and Cu(2+)in the microM range, and H(2)O(2) in the mM range, induced tyrosine phosphorylation. The effect of Cu(2+)was prevented by pre-incubation with genistein, while those of Hg(2+)and H(2)O(2) were only decreased, probably due to tyrosine kinase stimulation coupled to phosphatase inhibition. Phosphospecific antibodies against the three types of MAPKs showed that ERK is activated by heavy metals only, while p38 and SAPK/JNK are activated by H(2)O(2), Hg(2+), and Cu(2+) plus low H(2)O(2). Cell pre-incubation with p38 inhibitors indicated that ERK activation by H(2)O(2) is prevented by concomitant activation of p38. Phosphospecific STAT antibodies revealed activation by H(2)O(2) only. In conclusion, fish cell exposure to heavy metals and pro-oxidants produce specific tyrosine kinase responses, involving cross talk and redox modulatory effects. PMID:12876385

  15. Visualization of Nanofibrillar Cellulose in Biological Tissues Using a Biotinylated Carbohydrate Binding Module of β-1,4-Glycanase.

    Science.gov (United States)

    Knudsen, Kristina Bram; Kofoed, Christian; Espersen, Roall; Højgaard, Casper; Winther, Jakob Rahr; Willemoës, Martin; Wedin, Irene; Nuopponen, Markus; Vilske, Sara; Aimonen, Kukka; Weydahl, Ingrid Elise Konow; Alenius, Harri; Norppa, Hannu; Wolff, Henrik; Wallin, Håkan; Vogel, Ulla

    2015-08-17

    Nanofibrillar cellulose is a very promising innovation with diverse potential applications including high quality paper, coatings, and drug delivery carriers. The production of nanofibrillar cellulose on an industrial scale may lead to increased exposure to nanofibrillar cellulose both in the working environment and the general environment. Assessment of the potential health effects following exposure to nanofibrillar cellulose is therefore required. However, as nanofibrillar cellulose primarily consists of glucose moieties, detection of nanofibrillar cellulose in biological tissues is difficult. We have developed a simple and robust method for specific and sensitive detection of cellulose fibers, including nanofibrillar cellulose, in biological tissue, using a biotinylated carbohydrate binding module (CBM) of β-1,4-glycanase (EXG:CBM) from the bacterium Cellulomonas fimi. EXG:CBM was expressed in Eschericia coli, purified, and biotinylated. EXG:CBM was shown to bind quantitatively to five different cellulose fibers including four different nanofibrillar celluloses. Biotinylated EXG:CBM was used to visualize cellulose fibers by either fluorescence- or horse radish peroxidase (HRP)-tagged avidin labeling. The HRP-EXG:CBM complex was used to visualize cellulose fibers in both cryopreserved and paraffin embedded lung tissue from mice dosed by pharyngeal aspiration with 10-200 μg/mouse. Detection was shown to be highly specific, and the assay appeared very robust. The present method represents a novel concept for the design of simple, robust, and highly specific detection methods for the detection of nanomaterials, which are otherwise difficult to visualize. PMID:26208679

  16. Production of in vivo biotinylated scFv specific to almond (Prunus dulcis) proteins by recombinant Pichia pastoris.

    Science.gov (United States)

    de la Cruz, Silvia; Alcocer, Marcos; Madrid, Raquel; García, Aina; Martín, Rosario; González, Isabel; García, Teresa

    2016-06-10

    The methylotropic yeast Pichia pastoris has demonstrated its suitability for large-scale production of recombinant proteins. As an eukaryotic organism P. pastoris presents a series of advantages at expression and processing of heterologous proteins when compared with Escherichia coli. In this work, P. pastoris has been used to express a scFv from a human synthetic library previously shown to bind almond proteins. In order to facilitate purification and post processing manipulations, the scFv was engineered with a C-terminal tag and biotinylated in vivo. After purification, biotinylated scFv were bound to avidin conjugated with HRP producing a multimeric scFv. The multimeric scFv showed to maintain their ability to recognize almond protein when assayed in ELISA, reaching a LOD of 470mgkg(-1). This study describes an easy method to produce large quantities of in vivo biotinylated scFv in P. pastoris. By substituting the enzyme or fluorochromes linked to avidin, it will be possible to generate a diverse number of multimeric scFv as probes to suit different analytical platforms in the detection of almond in food products. PMID:27085890

  17. Capture of endogenously biotinylated proteins from Pseudomonas aeruginosa displays unexpected downregulation of LiuD upon iron nutrition.

    Science.gov (United States)

    Kaschani, Farnusch; Wei, Qing; Dingemans, Jozef; van der Hoorn, Renier A L; Cornelis, Pierre; Kaiser, Markus

    2016-08-01

    The uptake and storage but also removal of excess iron are of utmost importance to microorganisms since surplus levels of iron may lead to the formation of reactive oxygen species. Therefore, iron homeostasis is generally tightly regulated by the ferric uptake regulator (Fur), a global iron regulator acting as a transcriptional repressor. While detecting biotinylated proteins in labelling experiments, we discovered that the endogenously biotinylated protein LiuD differentially accumulated upon iron treatment. LiuD represents the α-subunit of the methylcrotonyl-CoA-carboxylase (MCCase), an enzyme from the leucine/isovalerate utilization pathway. Real-time PCR transcription analysis revealed that the observed lower levels of LiuD biotinylation could be traced back to lower LiuD protein levels via a transcriptional repression of liuABCDE expression that however does not seem to be mediated by Fur. In accordance with LiuD's role for the leucine/isovalerate utilization pathway and its protein level regulation by nutritional iron levels, we found that wild-type Pseudomonas aeruginosa did not grow in the presence of iron if the medium contained only leucine as a carbon source. Conversely, iron stimulated the growth when glucose was used as a carbon source. Our study thus demonstrates the complexities of iron-regulated bacterial growth in Pseudomonas aeruginosa. PMID:27160053

  18. Identification of genomic regions that interact with a viable allele of the Drosophila protein tyrosine phosphatase corkscrew.

    OpenAIRE

    Firth, L; Manchester, J; Lorenzen, J A; Baron, M.; Perkins, L A

    2000-01-01

    Signaling by receptor tyrosine kinases (RTKs) is critical for a multitude of developmental decisions and processes. Among the molecules known to transduce the RTK-generated signal is the nonreceptor protein tyrosine phosphatase Corkscrew (Csw). Previously, Csw has been demonstrated to function throughout the Drosophila life cycle and, among the RTKs tested, Csw is essential in the Torso, Sevenless, EGF, and Breathless/FGF RTK pathways. While the biochemical function of Csw remains to be unamb...

  19. Antagonistic regulation of swelling-activated Cl− current in rabbit ventricle by Src and EGFR protein tyrosine kinases

    OpenAIRE

    Ren, Zuojun; Baumgarten, Clive M.

    2005-01-01

    Regulation of swelling-activated Cl− current (ICl,swell) is complex, and multiple signaling cascades are implicated. To determine whether protein tyrosine kinase (PTK) modulates ICl,swell and to identify the PTK involved, we studied the effects of a broad-spectrum PTK inhibitor (genistein), selective inhibitors of Src (PP2, a pyrazolopyrimidine) and epidermal growth factor receptor (EGFR) kinase (PD-153035), and a protein tyrosine phosphatase (PTP) inhibitor (orthovanadate). ICl,swell evoked ...

  20. Development of an efficient signal amplification strategy for label-free enzyme immunoassay using two site-specific biotinylated recombinant proteins

    International Nuclear Information System (INIS)

    Highlights: • An efficient signal amplification strategy for label-free EIA is proposed. • Divalent biotinylated AP and monovalent biotinylated ZZ were prepared via Avitag–BirA system. • The above site-specific biotinylated fusion proteins form complex via SA–biotin interaction. • The mechanism relies on the ZZ–Avi-B/SA/AP–(Avi-B)2 complex. • The analytical signals are enhanced (32-fold) by the proposed strategy. - Abstract: Constructing a recombinant protein between a reporter enzyme and a detector protein to produce a homogeneous immunological reagent is advantageous over random chemical conjugation. However, the approach hardly recombines multiple enzymes in a difunctional fusion protein, which results in insufficient amplification of the enzymatic signal, thereby limiting its application in further enhancement of analytical signal. In this study, two site-specific biotinylated recombinant proteins, namely, divalent biotinylated alkaline phosphatase (AP) and monovalent biotinylated ZZ domain, were produced by employing the Avitag–BirA system. Through the high streptavidin (SA)–biotin interaction, the divalent biotinylated APs were clustered in the SA–biotin complex and then incorporated with the biotinylated ZZ. This incorporation results in the formation of a functional macromolecule that involves numerous APs, thereby enhancing the enzymatic signal, and in the production of several ZZ molecules for the interaction with immunoglobulin G (IgG) antibody. The advantage of this signal amplification strategy is demonstrated through ELISA, in which the analytical signal was substantially enhanced, with a 32-fold increase in the detection sensitivity compared with the ZZ–AP fusion protein approach. The proposed immunoassay without chemical modification can be an alternative strategy to enhance the analytical signals in various applications involving immunosensors and diagnostic chips, given that the label-free IgG antibody is suitable for the

  1. Development of an efficient signal amplification strategy for label-free enzyme immunoassay using two site-specific biotinylated recombinant proteins

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jin-Bao [School of Pharmacy, Weifang Medical University, Weifang 261053 (China); Tang, Ying [Affiliated Hospital of Weifang Medical University, Weifang 261041 (China); Yang, Hong-Ming, E-mail: yanghongming2006@sohu.com [School of Pharmacy, Weifang Medical University, Weifang 261053 (China)

    2015-02-15

    Highlights: • An efficient signal amplification strategy for label-free EIA is proposed. • Divalent biotinylated AP and monovalent biotinylated ZZ were prepared via Avitag–BirA system. • The above site-specific biotinylated fusion proteins form complex via SA–biotin interaction. • The mechanism relies on the ZZ–Avi-B/SA/AP–(Avi-B){sub 2} complex. • The analytical signals are enhanced (32-fold) by the proposed strategy. - Abstract: Constructing a recombinant protein between a reporter enzyme and a detector protein to produce a homogeneous immunological reagent is advantageous over random chemical conjugation. However, the approach hardly recombines multiple enzymes in a difunctional fusion protein, which results in insufficient amplification of the enzymatic signal, thereby limiting its application in further enhancement of analytical signal. In this study, two site-specific biotinylated recombinant proteins, namely, divalent biotinylated alkaline phosphatase (AP) and monovalent biotinylated ZZ domain, were produced by employing the Avitag–BirA system. Through the high streptavidin (SA)–biotin interaction, the divalent biotinylated APs were clustered in the SA–biotin complex and then incorporated with the biotinylated ZZ. This incorporation results in the formation of a functional macromolecule that involves numerous APs, thereby enhancing the enzymatic signal, and in the production of several ZZ molecules for the interaction with immunoglobulin G (IgG) antibody. The advantage of this signal amplification strategy is demonstrated through ELISA, in which the analytical signal was substantially enhanced, with a 32-fold increase in the detection sensitivity compared with the ZZ–AP fusion protein approach. The proposed immunoassay without chemical modification can be an alternative strategy to enhance the analytical signals in various applications involving immunosensors and diagnostic chips, given that the label-free IgG antibody is suitable

  2. Insulin receptor substrate 2 content and tyrosine phosphorylation in diabetes mellitus rat skeletal muscle cells and the correlations with different densities of exercises%糖尿病大鼠骨骼肌细胞胰岛素受体底物2含量及磷酸化变化与不同强度运动的关系

    Institute of Scientific and Technical Information of China (English)

    李永春

    2009-01-01

    BACKGROUND: Exercise can enhance the sensitivity and action effects of insulin. Its effects on insulin are closely related to skeletal muscle cell insulin receptor substrate 2 (IRS-2)-mediated function.OBJECTIVE: To investigate the effects of different densities of exercise on ISR-2 protein content and tyrosine phohorylation in diabetes mellitus rat skeletal muscle cells.DESIGN, TIME AND SETTING: A randomized controlled animal experiment was performed at the Laboratory of Physical Education institute of Liaoning Normal University between April and June 2008.MATERIALS: A total of 60 healthy Sprague-Dawley (SD) rats were randomly divided into 6 groups, with 10 rats per group: normal control, diabetes mellitus control, exercise intensity 15, 20, 25, and 30 m/min.METHODS: Diabetes mellitus was induced in rats by an intraperioneal injection of streptozocin in all groups except for the normal control group, in which, the same amount of citrate buffer solution was given. Diabetes mellitus rats were daily forced to do 50-minute exercise at an intensity of 15, 20, 25, or 30 m/min, 6 days a week, for a total of 6 weeks. Exercise was not given in the normal control and diabetes mellitus control groups. MAIN OUTCOME MEASURES: IRS-2 protein content and tyrosine phosphorylation in the rat skeletal muscle cells were examined by Western blot analysis.RESULTS: Compared with diabetes mellitus control group, IRS-2 content increased by 17%, 24.4%, 23.4%, and 21.3% in the 15, 20, 25, and 30 m/min groups accordingly (P<0.05 or P<0.01), and tyrosine phosphorytation of IRS-2 protein was enhanced by 34.7%, 37.2%, 40.2%, and 38.8% in these four groups (P<0.01), But the IRS-2 protein content and its tyrosine phosphorylation did not recover to levels of normal control group. There was no statistical significance in IRS-2 protein expression and tyrosine phosphorylation among exercise intensity 15, 20, 25, and 30 m/min groups.CONCLUSION: Under different intensities of exercise, IRS-2 protein

  3. De novo design of VEGFR-2 tyrosine kinase inhibitors based on a linked-fragment approach.

    Science.gov (United States)

    Liu, Yi-Zhou; Wang, Xiao-Li; Wang, Xin-Ying; Yu, Ri-Lei; Liu, Dong-Qing; Kang, Cong-Min

    2016-09-01

    Vascular endothelial growth factor receptor-2 (VEGFR-2) tyrosine kinase inhibitors have been demonstrated to possess substantial antitumor activity. VEGFR-2 tyrosine kinase inhibitors are crucial for development of antitumor drugs. Based on the crystal structure of VEGFR-2 tyrosine kinase, a linked-fragment strategy was employed to design novel VEGFR-2 tyrosine kinase inhibitors, and 1000 compounds were generated in this process. Absorption, distribution, metabolism, excretion and toxicity (ADMET) were used to screen the 1000 compounds, and 59 compounds were acceptable. Scaffold hopping was then used for further screening, and only four compounds were obtained in this way. Then, the binding energy of the four molecules to VEGFR-2 tyrosine kinase was calculated using molecular docking, and their values were found to be lower than that of Sorafenib. Finally, molecular dynamics simulations were performed on the complex of the compound with the lowest binding energy with VEGFR-2 tyrosine kinase, and the binding model was analyzed. At the end, four chemical entities with novel structures were obtained, and were suggested for experimental testing in future studies. PMID:27558799

  4. Tyrosines 868, 966, and 972 in the Kinase Domain of JAK2 Are Autophosphorylated and Required for Maximal JAK2 Kinase Activity

    OpenAIRE

    Argetsinger, Lawrence S.; Stuckey, Jeanne A.; Robertson, Scott A.; Koleva, Rositsa I.; Cline, Joel M.; Marto, Jarrod A.; Myers, Martin G.; Carter-Su, Christin

    2010-01-01

    Janus kinase 2 (JAK2) is activated by a majority of cytokine family receptors including receptors for GH, leptin, and erythropoietin. To identify novel JAK2-regulatory and/or -binding sites, we set out to identify autophosphorylation sites in the kinase domain of JAK2. Two-dimensional phosphopeptide mapping of in vitro autophosphorylated JAK2 identified tyrosines 868, 966, and 972 as sites of autophosphorylation. Phosphorylated tyrosines 868 and 972 were also identified by mass spectrometry a...

  5. Tyrosine phosphorylation profiling in FGF-2 stimulated human embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Vanessa M Y Ding

    Full Text Available The role of fibroblast growth factor-2 (FGF-2 in maintaining undifferentiated human embryonic stem cells (hESC was investigated using a targeted phosphoproteomics approach to specifically profile tyrosine phosphorylation events following FGF-2 stimulation. A cumulative total number of 735 unique tyrosine phosphorylation sites on 430 proteins were identified, by far the largest inventory to date for hESC. Early signaling events in FGF-2 stimulated hESC were quantitatively monitored using stable isotope dimethyl labeling, resulting in temporal tyrosine phosphorylation profiles of 316 unique phosphotyrosine peptides originating from 188 proteins. Apart from the rapid activation of all four FGF receptors, trans-activation of several other receptor tyrosine kinases (RTKs was observed as well as induced tyrosine phosphorylation of downstream proteins such as PI3-K, MAPK and several Src family members. Both PI3-K and MAPK have been linked to hESC maintenance through FGF-2 mediated signaling. The observed activation of the Src kinase family members by FGF-2 and loss of pluripotent marker expression post Src kinase inhibition may point to the regulation of cytoskeletal and actin depending processes to maintain undifferentiated hESC.

  6. Bombesin, vasopressin, and endothelin rapidly stimulate tyrosine phosphorylation in intact Swiss 3T3 cells

    Energy Technology Data Exchange (ETDEWEB)

    Zachary, I.; Gil, J.; Lehmann, W.; Sinnett-Smith, J.; Rozengurt, E. (Imperial Cancer Research Fund, London (England))

    1991-06-01

    The mitogenic neuropeptides bombesin and vasopressin markedly increased tyrosine and serine phosphorylation of multiple substrates in quiescent Swiss 3T3 fibroblasts, including two major bands of M{sub r} 90,000 and 115,000. Tyrosine phosphorylation of these proteins was increased as judged by immunoprecipitation of {sup 32}P{sub i}-labeled cells and immunoblotting of unlabeled cells with monoclonal antiphosphotyrosine antibodies, elution with phenyl phosphate, and phospho amino acid analysis. Phosphotyrosyl proteins generated by bombesin and vasopressin did not correspond either by apparent molecular weight or by immunological and biochemical criteria to several known tyrosine kinase substrates, including phospholipase C{sub {gamma}}, the microtubule-associated protein 2 kinase, GTPase-activating protein, or phosphatidylinositol kinase. The effect was rapid (within seconds), concentration dependent, and inhibited by specific receptor antagonists for both bombesin and vasopressin. The endothelin-related peptide, vasoactive intestinal contractor, also elicited a rapid and concentration-dependent tyrosine/serine phosphorylation of a similar set of substrates. These results demonstrate that neuropeptides, acting through receptors linked to GTP-binding proteins, stimulate tyrosine phosphorylation of a common set of substrates in quiescent Swiss 3T3 cells and suggest the existence of an additional signal transduction pathway in neuropeptide-induced mitogenesis.

  7. Agonism and antagonism at the insulin receptor

    DEFF Research Database (Denmark)

    Knudsen, Louise; Hansen, Bo Falck; Jensen, Pia; Pedersen, Thomas Åskov; Vestergaard, Kirsten; Schäffer, Lauge; Blagoev, Blagoy; Oleksiewicz, Martin B; Kiselyov, Vladislav V; De Meyts, Pierre Marcel Joseph

    2012-01-01

    insulin analogues. The occurrence of ligand agonism and antagonism is well described for G protein-coupled receptors (GPCRs) and other receptors but in general, with the exception of antibodies, not for receptor tyrosine kinases (RTKs). In the case of the IR, no natural ligand or insulin analogue has been...

  8. Epidermal growth factor stimulates substrate-selective protein-tyrosine-phosphatase activity.

    OpenAIRE

    Hernández-Sotomayor, S M; Arteaga, C L; Soler, C. (Carlos); Carpenter, G

    1993-01-01

    This study investigates the regulation of protein-tyrosine-phosphatase (PTPase; EC 3.1.3.48) activity by epidermal growth factor (EGF). Cytosol from EGF-treated A-431 human epidermoid carcinoma cells was used as a source of PTPase activity, and tyrosine-phosphorylated ErbB2, EGF receptor, phospholipase C-gamma 1, and the Ras GTPase-activating protein were used as substrates to monitor PTPase activity. EGF stimulated PTPase activity that was selective toward these substrates, as it dephosphory...

  9. Immunobiology of the TAM receptors

    OpenAIRE

    Lemke, Greg; Rothlin, Carla V.

    2008-01-01

    Recent studies have revealed that the TAM receptor protein tyrosine kinases — TYRO3, AXL and MER — have pivotal roles in innate immunity. They inhibit inflammation in dendritic cells and macrophages, promote the phagocytosis of apoptotic cells and membranous organelles, and stimulate the maturation of natural killer cells. Each of these phenomena may depend on a cooperative interaction between TAM receptor and cytokine receptor signalling systems. Although its importance was previously unreco...

  10. Posttranslational Modification Biology of Glutamate Receptors and Drug Addiction

    OpenAIRE

    Fibuch, Eugene E.; Wang, John Q.

    2011-01-01

    Posttranslational covalent modifications of glutamate receptors remain a hot topic. Early studies have established that this family of receptors, including almost all ionotropic and metabotropic glutamate receptor subtypes, undergoes active phosphorylation at serine, threonine, or tyrosine residues on their intracellular domains. Recent evidence identifies several glutamate receptor subtypes to be direct substrates for palmitoylation at cysteine residues. Other modifications such as ubiqui...

  11. Activation of the neu tyrosine kinase induces the fos/jun transcription factor complex, the glucose transporter and ornithine decarboxylase

    OpenAIRE

    1989-01-01

    We have studied the ability of the neu tyrosine kinase to induce a signal for the activation of cell growth-regulated genes. Serum-starved NIH 3T3 cells expressing an epidermal growth factor receptor (EGF- R)/neu construct encoding a hybrid receptor protein were stimulated with EGF and the activation of the neu tyrosine kinase and stimulation of growth factor inducible genes were followed at the mRNA, protein, and activity levels, and compared to the corresponding responses in the neu proto-o...

  12. Suppressor of Cytokine Signaling 6 (SOCS6) Negatively Regulates Flt3 Signal Transduction through Direct Binding to Phosphorylated Tyrosines 591 and 919 of Flt3

    DEFF Research Database (Denmark)

    Kazi, Julhash U; Sun, Jianmin; Phung, Bengt;

    2012-01-01

    The receptor tyrosine kinase Flt3 is an important growth factor receptor in hematopoiesis, and gain-of-function mutations of the receptor contribute to the transformation of acute myeloid leukemia. SOCS6 (suppressor of cytokine signaling 6) is a member of the SOCS family of E3 ubiquitin ligases...... that can regulate receptor tyrosine kinase signal transduction. In this study, we analyzed the role of SOCS6 in Flt3 signal transduction. The results show that ligand stimulation of Flt3 can induce association of SOCS6 and Flt3 and tyrosine phosphorylation of SOCS6. Phosphopeptide fishing indicated...... that SOCS6 binds directly to phosphotyrosines 591 and 919 of Flt3. By using stably transfected Ba/F3 cells with Flt3 and/or SOCS6, we show that the presence of SOCS6 can enhance ubiquitination of Flt3, as well as internalization and degradation of the receptor. The presence of SOCS6 also induces weaker...

  13. A chemically cleavable biotinylated nucleotide: usefulness in the recovery of protein-DNA complexes from avidin affinity columns.

    OpenAIRE

    Shimkus, M; Levy, J; Herman, T

    1985-01-01

    A biotinylated nucleotide analog containing a disulfide bond in the 12-atom linker joining biotin to the C-5 of the pyrimidine ring has been synthesized. This analog, Bio-SS-dUTP, is an efficient substrate for Escherichia coli DNA polymerase I. Bio-SS-dUTP supported DNA synthesis in a standard nick-translation reaction at 35%-40% the rate of an equal concentration of the normal nucleotide, TTP. DNA containing this analog was bound to an avidin-agarose affinity column and subsequently eluted a...

  14. Quantification of alpha-tubulin isotypes by sandwich ELISA with signal amplification through biotinyl-tyramide or immuno-PCR

    Czech Academy of Sciences Publication Activity Database

    Dráberová, Eduarda; Stegurová, Lucie; Sulimenko, Vadym; Hájková, Zuzana; Dráber, Petr; Dráber, Pavel

    2013-01-01

    Roč. 395, 1-2 (2013), s. 63-70. ISSN 0022-1759 R&D Projects: GA AV ČR KAN200520701; GA ČR GAP302/12/1673; GA ČR GPP302/11/P709; GA ČR GAP302/10/1759; GA ČR GA301/09/1826; GA MŠk(CZ) LD13015; GA MŠk LD12073 Institutional support: RVO:68378050 Keywords : alpha-tubulin isotypes * biotinyl-tyramide * ELISA * immuno-PCR * mast cells Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.005, year: 2013

  15. Enhanced Photoelectrochemical Detection of Bioaffinity Reactions by Vertically Oriented Au Nanobranches Complexed with a Biotinylated Polythiophene Derivative

    Directory of Open Access Journals (Sweden)

    Lei Jiang

    2009-02-01

    Full Text Available Four nanostructured Au electrodes were prepared by a simple and templateless electrochemical deposition technique. After complexing with a biotinylated polythiophene derivative (PTBL, photocurrent generation and performance of PTBL/Au-nanostructured electrodes as photoelectrochemical biosensors were investigated. Among these four nanostructured Au electrodes, vertically oriented nanobranches on the electrode significantly improved the photoelectric conversion, because the vertically oriented nanostructures not only benefit light harvesting but also the transfer of the photogenerated charge carriers. Owing to this advantaged nanostructure, the PTBL/Au-nanobranch electrode showed higher sensitivity and faster response times in the photoelectrochemical detection of a streptavidin-biotin affinity reaction compared to a PTBL/Au-nanoparticle electrode.

  16. Monoclonal antibodies to individual tyrosine-phosphorylated protein substrates of oncogene-encoded tyrosine kinases.

    OpenAIRE

    Kanner, S B; Reynolds, A B; Vines, R R; Parsons, J T

    1990-01-01

    Cellular transformation by oncogenic retroviruses encoding protein tyrosine kinases coincides with the tyrosine-specific phosphorylation of multiple protein substrates. Previous studies have shown that tyrosine phosphorylation of a protein of 120 kDa, p120, correlated with src transformation in chicken embryo fibroblasts. Additionally, we previously identified two phosphotyrosine-containing cellular proteins, p130 and p110, that formed stable complexes with activated variants of pp60src, the ...

  17. Genetics Home Reference: tyrosine hydroxylase deficiency

    Science.gov (United States)

    Skip to main content Your Guide to Understanding Genetic Conditions Enable Javascript for addthis links to activate. ... Conditions Genes Chromosomes & mtDNA Resources Help Me Understand Genetics Home Health Conditions TH deficiency tyrosine hydroxylase deficiency ...

  18. Nature and regulation of the insulin receptor: structure and function

    International Nuclear Information System (INIS)

    Native, cell-surface insulin receptor consists of two glycoprotein subunit types with apparent masses of about 125,000 daltons (alpha subunit) and 90,000 daltons (beta subunit). The alpha and beta insulin-receptor subunits seem to have distinct functions such that alpha appears to bind hormone whereas beta appears to possess intrinsic tyrosine kinase activity. In detergent extracts, insulin activates receptor autophosphorylation of tyrosine residues on its beta subunit, whereas in the presence of reductant, the alpha subunit is also phosphorylated. In intact cells, insulin activates serine/threonine phosphorylation of insulin receptor beta subunit as well as tyrosine phosphorylation. The biological role of the receptor-associated tyrosine kinase is not known. The insulin receptor kinase is regulated by beta-adrenergic agonists and other agents that elevate cAMP in adipocytes, presumably via the cAMP-dependent protein kinase. Such agents decrease receptor affinity for insulin and partially uncouple receptor tyrosine kinase activity from activation by insulin. These effects appear to contribute to the biological antagonism between insulin and beta-agonists. These data suggest the hypothesis that a complex network of tyrosine and serine/threonine phosphorylations on the insulin receptor modulate its binding and kinase activities in an antagonistic manner

  19. Protein tyrosine phosphorylation in synaptic vesicles.

    OpenAIRE

    Pang, D T; Wang, J K; Valtorta, F; Benfenati, F; Greengard, P.

    1988-01-01

    Protein tyrosine phosphorylation in purified synaptic vesicles from rat forebrain has been studied in the presence of Mn2+ and orthovanadate. High levels of endogenous protein tyrosine phosphorylation were observed. Four major phosphoproteins, with apparent molecular masses of 105, 94, 38, and 30 kDa, were shown to contain phosphotyrosine. The 38-kDa phosphoprotein was identified as synaptophysin (p38), a well-characterized integral membrane protein of synaptic vesicles. The three other phosp...

  20. Cloning and expression of catalytic domain of Abl protein tyrosine kinase gene in E. coli

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Protein tyrosine kinases (PTKs) regulate cell proliferation, differentiation and are involved in signal transduction. Uncontrolled signaling from receptor tyrosine kinases to intracellular tyrosine kinases can lead to inflamma tory responses and diseases such as cancer and atherosclerosis. Thus, inhibitors that block the activity of tyrosine kinases or the signaling pathways of PTKs activation could be assumed as the potential candidate for drug development. On this assumption, we cloned and expressed the Abl PTK gene in E. coli, and purified the PTK, which was used to screen the PTK inhibitors from the extracts of Chinese herbs. The catalytic domain sequence of PTK gene was amplified by PCR us ing the cDNA of abl from Abelson murine leukemia virus as template. The amplified fragment was then cloned into the GST-tagged expression vector pGEX2T. The recombinant plasmid was transformed into host cell E. coli DH5α and was induced to express PTK protein. The expression of the protein was detected using SDS-PAGE. The result showed that a specific protein was induced to express after 12 min induction, and reached peak level about 40% of the host total pro tein after 4 h induction. The molecular weight of the fusion protein was about 58 kD. The purified GST-PTK fusion pro tein presented higher activity for tyrosine phosphorylation.

  1. Tyrosine 402 phosphorylation of Pyk2 is involved in ionomycin-induced neurotransmitter release.

    Directory of Open Access Journals (Sweden)

    Zhao Zhang

    Full Text Available Protein tyrosine kinases, which are highly expressed in the central nervous system, are implicated in many neural processes. However, the relationship between protein tyrosine kinases and neurotransmitter release remains unknown. In this study, we found that ionomycin, a Ca²⁺ ionophore, concurrently induced asynchronous neurotransmitter release and phosphorylation of a non-receptor protein tyrosine kinase, proline-rich tyrosine kinase 2 (Pyk2, in clonal rat pheochromocytoma PC12 cells and cerebellar granule cells, whereas introduction of Pyk2 siRNA dramatically suppressed ionomycin-induced neurotransmitter release. Further study indicated that Tyr-402 (Y402 in Pyk2, instead of other tyrosine sites, underwent rapid phosphorylation after ionomycin induction in 1 min to 2 min. We demonstrated that the mutant of Pyk2 Y402 could abolish ionomycin-induced dopamine (DA release by transfecting cells with recombinant Pyk2 and its mutants (Y402F, Y579F, Y580F, and Y881F. In addition, Src inhibition could prolong phosphorylation of Pyk2 Y402 and increase DA release. These findings suggested that Pyk2 was involved in ionomycin-induced neurotransmitter release through phosphorylation of Y402.

  2. Tyrosine phosphorylation modulates store-operated calcium entry in cultured rat epididymal basal cells.

    Science.gov (United States)

    Zuo, Wu-Lin; Du, Jian-Yang; Huang, Jie-Hong; Li, Sheng; Zhang, Geng; Chen, Si-Liang; Ruan, Ye-Chun; Cheng, Christopher H K; Zhou, Wen-Liang

    2011-04-01

    Store-operated calcium entry (SOCE) is essential for many cellular processes. In this study, we investigated modulation of SOCE by tyrosine phosphorylation in rat epididymal basal cells. The intracellular Ca(2+) ([Ca(2+)]i) measurement showed that SOCE occurred in rat epididymal basal cells by pretreating the cells with thapsigargin (Tg), the inhibitor of sarco-endoplasmic reticulum Ca(2+)-ATPase. To identify the role of Ca(2+) channels in this response, we examined the effects of transient receptor potential canonical channel blockers 2-aminoethoxydiphenyl borate (2-APB), 1-[β-[3-(4-methoxyphenyl)pro-poxy]-4-methoxyphenethyl]-1H-imidazole hydrochloride(SKF96365), Gd(3+), and non-selective cation channel blocker Ni(2+) respectively on SOCE and found that these blockers could inhibit the Ca(2+) influx to different extent. Furthermore, we studied the regulation of SOCE by tyrosine kinase pathway. The inhibitor of tyrosine kinase genistein remarkably suppressed the SOCE response, whereas sodium orthovanadate, the inhibitor of tyrosine phosphatase, greatly enhanced it. The results suggest that tyrosine kinase pathway plays a significant role in the initiation of SOCE and positively modulates SOCE in epididymal basal cells. PMID:20857412

  3. OSCAR is a collagen receptor that costimulates osteoclastogenesis in DAP12-deficient humans and mice

    DEFF Research Database (Denmark)

    Barrow, Alexander David; Raynal, Nicolas; Levin Andersen, Thomas;

    2011-01-01

    Osteoclasts are terminally differentiated leukocytes that erode the mineralized bone matrix. Osteoclastogenesis requires costimulatory receptor signaling through adaptors containing immunoreceptor tyrosine-based activation motifs (ITAMs), such as Fc receptor common γ (FcRγ) and DNAX-activating pr...

  4. Membrane labeling of coral gastrodermal cells by biotinylation: the proteomic identification of surface proteins involving cnidaria-dinoflagellate endosymbiosis.

    Directory of Open Access Journals (Sweden)

    Hsing-Hui Li

    Full Text Available The cellular and molecular-scale processes underlying the stability of coral-Symbiodinium endosymbioses remain unclear despite decades of investigation. As the coral gastroderm is the only tissue layer characterized by this unique symbiotic association, the membranes of these symbiotic gastrodermal cells (SGCs may play important roles in the initiation and maintenance of the endosymbiosis. In order to elucidate the interactions between the endosymbiotic dinoflagellates and their coral hosts, a thorough characterization of SGC membranes is therefore required. Cell surface proteins of isolated SGCs were biotinylated herein by a cell impermeant agent, biotin-XX sulfosuccinimidyl ester. The in situ distribution of these biotinylated proteins was uncovered by both fluorescence and transmission electron microscopic imaging of proteins bound to Alexa Fluor® 488-conjugated streptavidin. The identity of these proteins was then determined by two-dimensional gel electrophoresis followed by liquid chromatography-tandem mass spectrometry. Nineteen (19 proteins were identified, and they are known to be involved in the molecular chaperone/stress response, cytoskeletal remodeling, and energy metabolism. These results not only reveal the molecular characters of the host SGC membrane, but also provide critical insight into understanding the possible role of host membranes in this ecologically important endosymbiotic association.

  5. Growth inhibition by tyrosine kinase inhibitors in mesothelioma cell lines.

    Science.gov (United States)

    Nutt, Joyce E; O'Toole, Kieran; Gonzalez, David; Lunec, John

    2009-06-01

    Clinical outcome following chemotherapy for malignant pleural mesothelioma is poor and improvements are needed. This preclinical study investigates the effect of five tyrosine kinase inhibitors (PTK787, ZD6474, ZD1839, SU6668 and SU11248) on the growth of three mesothelioma cell lines (NCI H226, NCI H28 and MSTO 211H), the presence of growth factor receptors and inhibition of their downstream signalling pathways. GI50 values were determined: ZD6474 and SU11248, mainly VEGFR2 inhibitors, gave the lowest GI50 across all cell lines (3.5-6.9 microM) whereas ZD1839 gave a GI50 in this range only in H28 cells. All cell lines were positive for EGFR, but only H226 cells were positive for VEGFR2 by Western blotting. ZD6474 and ZD1839 inhibited EGF-induced phosphorylation of EGFR, AKT and ERK, whereas VEGF-induced phosphorylation of VEGFR2 was completely inhibited with 0.1 microM SU11248. VEGFR2 was detected in tumour samples by immunohistochemistry. VEGFR2 tyrosine kinase inhibitors warrant further investigation in mesothelioma. PMID:19318229

  6. Erkitinib, a novel EGFR tyrosine kinase inhibitor screened using a ProteoChip system from a phytochemical library

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eung-Yoon; Choi, Young-Jin [Biochip Research Center, Hoseo University, Asan 336-795 (Korea, Republic of); Innopharmascreen, Inc., Asan 336-795 (Korea, Republic of); Park, Chan-Won [Biochip Research Center, Hoseo University, Asan 336-795 (Korea, Republic of); Dept. of Biological Science, Hoseo University, Asan 336-795 (Korea, Republic of); Kang, In-Cheol, E-mail: ickang@hoseo.edu [Biochip Research Center, Hoseo University, Asan 336-795 (Korea, Republic of); Dept. of Biological Science, Hoseo University, Asan 336-795 (Korea, Republic of); Innopharmascreen, Inc., Asan 336-795 (Korea, Republic of)

    2009-11-20

    Receptor tyrosine kinases (PTKs) play key roles in the pathogenesis of numerous human diseases, including cancer. Therefore PTK inhibitors are currently under intensive investigation as potential drug candidates. Herein, we report on a ProteoChip-based screening of an epidermal growth factor receptor (EGFR) tyrosine kinase (TK) inhibitor, Erkitinibs, from phytochemical libraries. PLC-{gamma}-1 was used as a substrate immobilized on a ProteoChip and incubated with an EGFR kinase to phosphorylate tyrosine residues of the substrate, followed by a fluorescence detection of the substrate recognized by a phospho-specific monoclonal antibody. Erkitinibs inhibited HeLa cell proliferation in a dose-dependent manner. In conclusion, these data suggest that Erkitinibs can be a specific inhibitor of an EGFR kinase and can be further developed as a potent anti-tumor agent.

  7. Radiolabeling and biotinylation of internalizing monoclonal antibody chimeric BR96: Potential use of extracorporeal immunoadsorption with enhanced tumor radioactivity retention of Iodine, Indium and Rhenium

    Energy Technology Data Exchange (ETDEWEB)

    Chen, JianQing

    1997-01-01

    In this thesis, methodology of radiolabeling and simultaneous biotinylation for internalizing monoclonal antibody chimeric BR96 have been investigated by using three element groups of potential therapeutic radionuclides iodine, indium and rhenium, and their different labeling methods. The biodistribution and kinetics of biotinylated and radiolabeled chiBR96 have been studied in colon carcinoma isografted rats. The potential use of ECIA, based on the biotin-avidin concept, has been evaluated and compared with the approach of avidin `chase` in the same animal tumor model with respect to an enhancement of tumor-to-normal tissue (T/N) activity ratio. 131 refs.

  8. Radiolabeling and biotinylation of internalizing monoclonal antibody chimeric BR96: Potential use of extracorporeal immunoadsorption with enhanced tumor radioactivity retention of Iodine, Indium and Rhenium

    International Nuclear Information System (INIS)

    In this thesis, methodology of radiolabeling and simultaneous biotinylation for internalizing monoclonal antibody chimeric BR96 have been investigated by using three element groups of potential therapeutic radionuclides iodine, indium and rhenium, and their different labeling methods. The biodistribution and kinetics of biotinylated and radiolabeled chiBR96 have been studied in colon carcinoma isografted rats. The potential use of ECIA, based on the biotin-avidin concept, has been evaluated and compared with the approach of avidin 'chase' in the same animal tumor model with respect to an enhancement of tumor-to-normal tissue (T/N) activity ratio. 131 refs

  9. HER2-targeted therapy in breast cancer. Monoclonal antibodies and tyrosine kinase inhibitors

    DEFF Research Database (Denmark)

    Nielsen, Dorte Lisbet; Andersson, Michael; Kamby, Claus

    2008-01-01

    There is strong clinical evidence that trastuzumab, a monoclonal antibody targeting the human epidermal growth factor receptor (HER) two tyrosine kinase receptor, is an important component of first-line treatment of patients with HER2-positive metastatic breast cancer. In particular the combination...... with taxanes and vinorelbine has been established. In the preoperative setting inclusion of trastuzumab has significantly increased the pathological complete response rate. Results from large phase III trials evaluating adjuvant therapy in HER2-positive early breast cancer indicate that the addition of...... trastuzumab to chemotherapy improves disease-free and overall survival. The use of lapatinib, a dual tyrosine kinase inhibitor of both HER1 and HER2, in combination with capecitabine in the second-line treatment of HER2-positive patients with metastatic breast cancer previously treated with trastuzumab has...

  10. Random Mutagenesis Reveals Residues of JAK2 Critical in Evading Inhibition by a Tyrosine Kinase Inhibitor

    OpenAIRE

    Marit, Michael R.; Chohan, Manprit; Matthew, Natasha; Huang, Kai; Kuntz, Douglas A.; Rose, David R.; Barber, Dwayne L.

    2012-01-01

    Background The non-receptor tyrosine kinase JAK2 is implicated in a group of myeloproliferative neoplasms including polycythemia vera, essential thrombocythemia, and primary myelofibrosis. JAK2-selective inhibitors are currently being evaluated in clinical trials. Data from drug-resistant chronic myeloid leukemia patients demonstrate that treatment with a small-molecule inhibitor generates resistance via mutation or amplification of BCR-ABL. We hypothesize that treatment with small molecule i...

  11. Expert Consensus on the Management of Adverse Events from EGFR Tyrosine Kinase Inhibitors in the UK

    OpenAIRE

    Califano, R; Tariq, N.; Compton, S.; Fitzgerald, D A; Harwood, C.A.; R. Lal; Lester, J.; McPhelim, J.; MULATERO, C; Subramanian, S.; Thomas, A; Thatcher, N.; Nicolson, M.

    2015-01-01

    Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) such as gefitinib, erlotinib, and afatinib are standard-of-care for first-line treatment of EGFR-mutant advanced non-small cell lung cancer (NSCLC). These drugs have a proven benefit in terms of higher response rate, delaying progression and improvement of quality of life over palliative platinum-based chemotherapy. The most common adverse events (AEs) are gastrointestinal (GI) (diarrhoea and stomatitis/mucositis) and c...

  12. Bruton tyrosine kinase inhibitors: a promising novel targeted treatment for B cell lymphomas

    OpenAIRE

    Aalipour, Amin; Advani, Ranjana H.

    2013-01-01

    Constitutive or aberrant signalling of the B cell receptor signalling cascade has been implicated in the propagation and maintenance of a variety of B cell malignancies. Small molecule inhibitors of Bruton tyrosine kinase (BTK), a protein early in this cascade and specifically expressed in B cells, have emerged as a new class of targeted agents. There are several BTK inhibitors, including ONO-WG-307, LFM-A13, dasatinib, CC-292, and PCI-32765 (ibrutinib), in preclinical and/or clinical develop...

  13. Identification of Bruton's tyrosine kinase as a therapeutic target in acute myeloid leukemia

    OpenAIRE

    Rushworth, Stuart A.; Murray, Megan Y; Zaitseva, Lyubov; Bowles, Kristian M.; MacEwan, David J.

    2014-01-01

    Bruton's tyrosine kinase (BTK) is a cytoplasmic protein found in all hematopoietic cell lineages except for T cells. BTK mediates signalling downstream of a number of receptors. Pharmacological targeting of BTK using ibrutinib (previously PCI-32765) has recently shown encouraging clinical activity in a range of lymphoid malignancies. This study reports for the first time that ibrutinib inhibits blast proliferation from human acute myeloid leukaemia (AML) and that treatment with ibrutinib sign...

  14. Targeting Bruton's tyrosine kinase signaling as an emerging therapeutic agent of B-cell malignancies

    OpenAIRE

    Xia, Bing; QU, FULIAN; Yuan, Tian; Zhang, Yizhuo

    2015-01-01

    It is becoming increasingly evident that B-cell receptor (BCR) signaling is central to the development and function of B cells. BCR signaling has emerged as a pivotal pathway and a key driver of numerous B-cell lymphomas. Disruption of BCR signaling can be lethal to malignant B cells. Recently, kinase inhibitors that target BCR signaling have induced notable clinical responses. These inhibitors include spleen tyrosine kinase, mammalian target of rapamycin, phosphoinositide 3′-kinase and Bruto...

  15. The SYK tyrosine kinase: a crucial player in diverse biological functions

    OpenAIRE

    Mócsai, Attila; Ruland, Jürgen; Tybulewicz, Victor L.J.

    2010-01-01

    Spleen tyrosine kinase (SYK) has been known to relay adaptive immune receptor signalling. However, recent reports indicate that SYK also mediates other, unexpectedly diverse biological functions including cellular adhesion, innate immune recognition, osteoclast maturation, platelet activation and vascular development. SYK is activated by C-type lectins and integrins, and activates novel targets including the CARD9/CARMA1–BCL10–MALT1 pathway and the NLRP3 inflammasome. Drosophila studies indic...

  16. Estrus cycle effect on muscle tyrosine kinase activity in bitches.

    Science.gov (United States)

    Gomes Pöppl, Álan; Costa Valle, Sandra; Hilário Díaz González, Félix; de Castro Beck, Carlos Afonso; Kucharski, Luiz Carlos; Silveira Martins Da Silva, Roselis

    2012-03-01

    Estrus cycle is a well recognized cause of insulin resistance in bitches. The insulin receptor (IR) as well as the insulin-like growth factor-I receptor belong to the same subfamily of tyrosine kinase (TK) receptors. The objective of this study was to evaluate basal TK activity in muscle tissue of bitches during the estrus cycle. Twenty-four bitches were used in the study (7 in anestrus, 7 in estrus, and 10 in diestrus). Muscle samples, taken after spaying surgery to determine TK activity, were immediately frozen in liquid nitrogen and then stored at -80°C until the membranes were prepared by sequential centrifugation after being homogenized. TK activity was determined by Poly (Glu 4:Tyr 1) phosphorylation and expressed in cpm/μg of protein. TK activity was significantly lower (P < 0.001) in the animals in estrus (104.5 ± 11.9 cpm/μg of protein) and diestrus (94.5 ± 16.9 cpm/μg of protein) when compared with bitches in anestrus (183.2 ± 39.2 cpm/μg of protein). These results demonstrate, for the first time, lower basal TK activity in the muscle tissue of female dogs during estrus and diestrus, which may represent lower insulin signaling capacity, opening a new field of investigation into the molecular mechanisms of insulin resistance in dogs. PMID:22139063

  17. Receptor tyrosine kinase signaling: a view from quantitative proteomics

    DEFF Research Database (Denmark)

    Dengjel, Joern; Kratchmarova, Irina; Blagoev, Blagoy

    2009-01-01

    signal transduction. Numerous new post-translational modification sites have been identified by quantitative mass spectrometry-based proteomics. In addition, plentiful new players in signal transduction have been identified underlining the complexity and the modular architecture of most signaling...... networks. In this review, we outline the principles of signal transduction via RTKs and highlight some of the new insights obtained from proteomic approaches such as protein microarrays and quantitative mass spectrometry....... RTKs. In recent years proteomic approaches have yielded detailed descriptions of cellular signaling events. Quantitative proteomics is able to characterize the exact position and strength of post-translational modifications (PTMs) providing essential information for understanding the molecular basis of...

  18. 中药治疗表皮生长因子受体酪氨酸激酶抑制剂相关皮疹的Meta分析%Meta-analysis of traditional Chinese medicine in the treatment of skin rash caused by epidermal growth factor receptor tyrosine kinase inhibitor

    Institute of Scientific and Technical Information of China (English)

    陈创; 王秀改; 刘振昌; 张羽

    2015-01-01

    Objective To evaluate the efficacy and safety of traditional Chinese medicine in the treatment of skin rash caused by epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI).Methods The clinical randomized controlled trials of traditional Chinese medicine in the treatment of EGFR-TKI-induced skin rash which published in domestic journals were selected.The quality assessment of included literature was made by Jadad score,RevMan 5.2 software was used to make Meta-analysis.Results A total of 6 studies met the inclusion criteria,the 6 studies included 248 patients,133 cases in the treatment group,115 cases in the control group.All patients were 30 to 75 years old.Compared with the control group,the combined OR value of the clinical efficacy of traditional Chinese medicine in the treatment of EGFR-TKIinduced rash was 7.51,with 95 % confidence interval 4.46-12.65.Conclusions Meta-analysis shows that the clinical efficacy of traditional Chinese medicine in the treatment of EGFR-TKI-induced skin rash is better than Western medicine,and no adverse reactions.It can be widely used in clinical practice.%目的 评价中药治疗表皮生长因子受体酪氨酸激酶抑制剂(EGFR-TKI)相关皮疹的疗效和安全性.方法 检索国内期刊公开发表的关于中药治疗EGFR-TKI相关皮疹的临床随机对照试验文献,对纳入的文献应用Jadad评分法进行质量评价,采用RevMan 5.2软件进行Meta分析.结果 共有6条文献符合纳入标准,共纳入248例患者,其中治疗组133例,对照组115例;患者年龄30 ~ 75岁.与对照组比较,中药治疗EGFR-TKI相关皮疹临床疗效的合并OR值为7.51,95%可信区间为4.46 ~12.65.结论 Meta分析结果显示中药治疗EGFR-TKI相关皮疹的疗效较西药好,且不良反应鲜见,安全性好,可在临床推广应用.

  19. Analysis of tyrosine-O-sulfation

    DEFF Research Database (Denmark)

    Bundgaard, J.R.; Sen, J.W.; Johnsen, A.H.; Rehfeld, Jens Frederik

    2008-01-01

    Tyrosine O-sulfation was first described about 50 years ago as a post-translational modification of fibrinogen. In the following 30 years it was considered to be a rare modification affecting only a few proteins and peptides. However, in the beginning of the 1980s tyrosine (Tyr) sulfation was shown...... to be a common modification and since then an increasing number of proteins have been identified as sulfated. The target proteins belong to the classes of secretory, plasma membrane, and lysosomal proteins, which reflects the intracellular localization of the enzymes catalyzing Tyr sulfation, the...... to demonstrate the presence of radioactively labeled tyrosine. These techniques have been described in detail previously. The aim of this chapter is to present alternative analytical methods of Tyr sulfation than radioisotope incorporation before analysis Udgivelsesdato: 2008...

  20. Monoclonal antibodies to individual tyrosine-phosphorylated protein substrates of oncogene-encoded tyrosine kinases

    International Nuclear Information System (INIS)

    Cellular transformation by oncogenic retroviruses encoding protein tyrosine kinases coincides with the tyrosine-specific phosphorylation of multiple protein substrates. Previous studies have shown that tyrosine phosphorylation of a protein of 120 kDa, p120, correlated with src transformation in chicken embryo fibroblasts. Additionally, the authors previously identified two phosphotyrosine-containing cellular proteins, p130 and p110, that formed stable complexes with activated variants of pp60src, the src-encoded tyrosine kinase. To study transformation-relevant tyrosine kinase substrates, they have generated monoclonal antibodies to individual tyrosine phosphoproteins, including p130, p120, p110, and five additional phosphoproteins (p210, p125, p118, p85, and p185/p64). These antibodies detected several of the same tyrosine phosphoproteins in chicken embryo fibroblasts transformed by avian retroviruses Y73 and CT10, encoding the yes and crk oncogenes, respectively. Protein substrates in mouse, rat, hamster, and human cells overexpressing activated variants of chicken pp60src were also detected by several of the monoclonal antibodies

  1. Protein-Tyrosine Phosphorylation in Bacillus subtilis

    DEFF Research Database (Denmark)

    Mijakovic, Ivan; Petranovic, Dina; Bottini, N.;

    2005-01-01

    phosphorylation, indicating that this post-translational modifi cation could regulate physiological processes ranging from stress response and exopolysaccharide synthesis to DNA metabolism. Some interesting work in this fi eld was done in Bacillus subtilis , and we here present the current state of knowledge on...... protein-tyrosine phosphorylation in this gram-positive model organism. With its two kinases, two kinase modulators, three phosphatases and at least four different tyrosine-phosphorylated substrates, B. subtilis is the bacterium with the highest number of presently known participants in the global network...

  2. Masitinib (AB1010, a potent and selective tyrosine kinase inhibitor targeting KIT.

    Directory of Open Access Journals (Sweden)

    Patrice Dubreuil

    Full Text Available BACKGROUND: The stem cell factor receptor, KIT, is a target for the treatment of cancer, mastocytosis, and inflammatory diseases. Here, we characterise the in vitro and in vivo profiles of masitinib (AB1010, a novel phenylaminothiazole-type tyrosine kinase inhibitor that targets KIT. METHODOLOGY/PRINCIPAL FINDINGS: In vitro, masitinib had greater activity and selectivity against KIT than imatinib, inhibiting recombinant human wild-type KIT with an half inhibitory concentration (IC(50 of 200+/-40 nM and blocking stem cell factor-induced proliferation and KIT tyrosine phosphorylation with an IC(50 of 150+/-80 nM in Ba/F3 cells expressing human or mouse wild-type KIT. Masitinib also potently inhibited recombinant PDGFR and the intracellular kinase Lyn, and to a lesser extent, fibroblast growth factor receptor 3. In contrast, masitinib demonstrated weak inhibition of ABL and c-Fms and was inactive against a variety of other tyrosine and serine/threonine kinases. This highly selective nature of masitinib suggests that it will exhibit a better safety profile than other tyrosine kinase inhibitors; indeed, masitinib-induced cardiotoxicity or genotoxicity has not been observed in animal studies. Molecular modelling and kinetic analysis suggest a different mode of binding than imatinib, and masitinib more strongly inhibited degranulation, cytokine production, and bone marrow mast cell migration than imatinib. Furthermore, masitinib potently inhibited human and murine KIT with activating mutations in the juxtamembrane domain. In vivo, masitinib blocked tumour growth in mice with subcutaneous grafts of Ba/F3 cells expressing a juxtamembrane KIT mutant. CONCLUSIONS: Masitinib is a potent and selective tyrosine kinase inhibitor targeting KIT that is active, orally bioavailable in vivo, and has low toxicity.

  3. A Fusion Protein between Streptavidin and the Endogenous TLR4 Ligand EDA Targets Biotinylated Antigens to Dendritic Cells and Induces T Cell Responses In Vivo

    Directory of Open Access Journals (Sweden)

    Laura Arribillaga

    2013-01-01

    Full Text Available The development of tools for efficient targeting of antigens to antigen presenting cells is of great importance for vaccine development. We have previously shown that fusion proteins containing antigens fused to the extra domain A from fibronectin (EDA, an endogenous TLR4 ligand, which targets antigens to TLR4-expressing dendritic cells (DC, are highly immunogenic. To facilitate the procedure of joining EDA to any antigen of choice, we have prepared the fusion protein EDAvidin by linking EDA to the N terminus of streptavidin, allowing its conjugation with biotinylated antigens. We found that EDAvidin, as streptavidin, forms tetramers and binds biotin or biotinylated proteins with a Kd ~ 2.6 × 10−14 mol/L. EDAvidin favours the uptake of biotinylated green fluorescent protein by DC. Moreover, EDAvidin retains the proinflammatory properties of EDA, inducing NF-κβ by TLR4-expressing cells, as well as the production of TNF-α by the human monocyte cell line THP1 and IL-12 by DC. More importantly, immunization of mice with EDAvidin conjugated with the biotinylated nonstructural NS3 protein from hepatitis C virus induces a strong anti-NS3 T cell immune response. These results open a new way to use the EDA-based delivery tool to target any antigen of choice to DC for vaccination against infectious diseases and cancer.

  4. A fusion protein between streptavidin and the endogenous TLR4 ligand EDA targets biotinylated antigens to dendritic cells and induces T cell responses in vivo.

    Science.gov (United States)

    Arribillaga, Laura; Durantez, Maika; Lozano, Teresa; Rudilla, Francesc; Rehberger, Federico; Casares, Noelia; Villanueva, Lorea; Martinez, Marta; Gorraiz, Marta; Borrás-Cuesta, Francisco; Sarobe, Pablo; Prieto, Jesús; Lasarte, Juan José

    2013-01-01

    The development of tools for efficient targeting of antigens to antigen presenting cells is of great importance for vaccine development. We have previously shown that fusion proteins containing antigens fused to the extra domain A from fibronectin (EDA), an endogenous TLR4 ligand, which targets antigens to TLR4-expressing dendritic cells (DC), are highly immunogenic. To facilitate the procedure of joining EDA to any antigen of choice, we have prepared the fusion protein EDAvidin by linking EDA to the N terminus of streptavidin, allowing its conjugation with biotinylated antigens. We found that EDAvidin, as streptavidin, forms tetramers and binds biotin or biotinylated proteins with a Kd ~ 2.6 × 10(-14) mol/L. EDAvidin favours the uptake of biotinylated green fluorescent protein by DC. Moreover, EDAvidin retains the proinflammatory properties of EDA, inducing NF- κβ by TLR4-expressing cells, as well as the production of TNF- α by the human monocyte cell line THP1 and IL-12 by DC. More importantly, immunization of mice with EDAvidin conjugated with the biotinylated nonstructural NS3 protein from hepatitis C virus induces a strong anti-NS3 T cell immune response. These results open a new way to use the EDA-based delivery tool to target any antigen of choice to DC for vaccination against infectious diseases and cancer. PMID:24093105

  5. Chlorinated tyrosine derivatives in insect cuticle

    DEFF Research Database (Denmark)

    Andersen, Svend Olav

    2004-01-01

    , not-yet sclerotized cuticle of adult femur and tibia, the amounts increased rapidly during the first 24 h after ecdysis and more slowly during the next two weeks. Control analyses using stable isotope dilution mass spectrometry have confirmed that the chlorinated tyrosines are not artifacts formed...

  6. Mechanisms underlying the inhibitory effects of arsenic compounds on protein tyrosine phosphatase (PTP)

    International Nuclear Information System (INIS)

    Arsenic binding to biomolecules is considered one of the major toxic mechanisms, which may also be related to the carcinogenic risks of arsenic in humans. At the same time, arsenic is also known to activate the phosphorylation-dependent signaling pathways including the epidermal growth factor receptor, the mitogen-activated protein kinase and insulin/insulin-like growth factor-1 pathways. These signaling pathways originate at the level of receptor tyrosine kinases whose phosphorylation status is regulated by opposing protein tyrosine phosphatase (PTP) activity. Reversible tyrosine phosphorylation, which is governed by the balanced action of protein tyrosine kinases and phosphatases, regulates important signaling pathways that are involved in the control of cell proliferation, adhesion and migration. In the present study, we have focused on the interaction of cellular PTPs with toxic trivalent arsenite (iAsIII) and its intermediate metabolites such as monomethylarsonous acid (MMAIII) and dimethylarsinous acid (DMAIII) in vitro, and then determined the arsenic binding site in PTP by the use of recombinant PTPs (e.g., PTP1B and CD45). Interestingly, the activities of PTP1B (cytoplasm-form) or CD45 (receptor-linked form) were observed to be strongly inhibited by both methylated metabolites (i.e., MMAIII and DMAIII) but not by iAsIII. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) has clearly confirmed that the organic intermediate, DMAIII directly bound to the active site cysteine residue of PTP1B (e.g., Cys215), resulting in inhibition of enzyme activity. These results suggest that arsenic exposure may disturb the cellular signaling pathways through PTP inactivation. Highlights: ► This study focused on the interaction of PTPs with trivalent arsenicals in vitro. ► We for the first time confirmed that DMAIII strongly inhibited activity of PTP1B. ► DMAIII directly bound to PTP1B, resulting in inhibition of enzyme

  7. Role of Tyrosine Kinase Inhibitors in Indolent and Other Mature B-Cell Neoplasms

    Science.gov (United States)

    Kutsch, Nadine; Marks, Reinhard; Ratei, Richard; Held, Thomas K; Schmidt-Hieber, Martin

    2015-01-01

    Targeting tyrosine kinases represents a highly specific treatment approach for different malignancies. This also includes non-Hodgkin lymphoma since it is well known that these enzymes are frequently involved in the lymphomagenesis. Hereby, tyrosine kinases might either be dysregulated intrinsically or be activated within signal transduction pathways leading to tumor survival and growth. Among others, Bruton’s tyrosine kinase (Btk) is of particular interest as a potential therapeutic target. Btk is stimulated by B-cell receptor signaling and activates different transcription factors such as nuclear factor κB. The Btk inhibitor ibrutinib has been approved for the treatment of chronic lymphocytic leukemia and mantle-cell lymphoma recently. Numerous clinical trials evaluating this agent in different combinations (eg, with rituximab or classical chemotherapeutic agents) as a treatment option for aggressive and indolent lymphoma are under way. Here, we summarize the role of tyrosine kinase inhibitors in the treatment of indolent and other non-Hodgkin lymphomas (eg, mantle-cell lymphoma). PMID:26327780

  8. Engagement of CD81 induces ezrin tyrosine phosphorylation and its cellular redistribution with filamentous actin

    Energy Technology Data Exchange (ETDEWEB)

    Coffey, Greg P.; Rajapaksa, Ranjani; Liu, Raymond; Sharpe, Orr; Kuo, Chiung-Chi; Wald Krauss, Sharon; Sagi, Yael; Davis, R. Eric; Staudt, Louis M.; Sharman, Jeff P.; Robinson, William H.; Levy, Shoshana

    2009-06-09

    CD81 is a tetraspanin family member involved in diverse cellular interactions in the immune and nervous systems and in cell fusion events. However, the mechanism of action of CD81 and of other tetraspanins has not been defined. We reasoned that identifying signaling molecules downstream of CD81 would provide mechanistic clues. We engaged CD81 on the surface of Blymphocytes and identified the induced tyrosine-phosphorylated proteins by mass spectrometry. This analysis showed that the most prominent tyrosine phosphorylated protein was ezrin, an actin binding protein and a member of the ezrin-radixin-moesin family. We also found that CD81 engagement induces spleen tyrosine kinase (Syk) and that Syk was involved in tyrosine phosphorylation of ezrin. Ezrin colocalized with CD81 and F-actin upon stimulation and this association was disrupted when Syk activation was blocked. Taken together, these studies suggest a model in which CD81 interfaces between the plasma membrane and the cytoskeleton by activating Syk, mobilizing ezrin, and recruiting F-actin to facilitate cytoskeletal reorganization and cell signaling. This may be a mechanism explaining the pleiotropic effects induced in response to stimulating cells by anti-CD81 antibodies or by the hepatitis C virus, which uses this molecule as its key receptor.

  9. Tyrosine-sulfated V2 peptides inhibit HIV-1 infection via coreceptor mimicry.

    Science.gov (United States)

    Cimbro, Raffaello; Peterson, Francis C; Liu, Qingbo; Guzzo, Christina; Zhang, Peng; Miao, Huiyi; Van Ryk, Donald; Ambroggio, Xavier; Hurt, Darrell E; De Gioia, Luca; Volkman, Brian F; Dolan, Michael A; Lusso, Paolo

    2016-08-01

    Tyrosine sulfation is a post-translational modification that facilitates protein-protein interaction. Two sulfated tyrosines (Tys173 and Tys177) were recently identified within the second variable (V2) loop of the major HIV-1 envelope glycoprotein, gp120, and shown to contribute to stabilizing the intramolecular interaction between V2 and the third variable (V3) loop. Here, we report that tyrosine-sulfated peptides derived from V2 act as structural and functional mimics of the CCR5 N-terminus and potently block HIV-1 infection. Nuclear magnetic and surface plasmon resonance analyses indicate that a tyrosine-sulfated V2 peptide (pV2α-Tys) adopts a CCR5-like helical conformation and directly interacts with gp120 in a CD4-dependent fashion, competing with a CCR5 N-terminal peptide. Sulfated V2 mimics, but not their non-sulfated counterparts, inhibit HIV-1 entry and fusion by preventing coreceptor utilization, with the highly conserved C-terminal sulfotyrosine, Tys177, playing a dominant role. Unlike CCR5 N-terminal peptides, V2 mimics inhibit a broad range of HIV-1 strains irrespective of their coreceptor tropism, highlighting the overall structural conservation of the coreceptor-binding site in gp120. These results document the use of receptor mimicry by a retrovirus to occlude a key neutralization target site and provide leads for the design of therapeutic strategies against HIV-1. PMID:27389109

  10. Avidin-biotin system: a small library of cysteine biotinylated derivatives designed for the [99mTc(N)(PNP)]2+ metal fragment

    International Nuclear Information System (INIS)

    Using the avidin-biotin system as model, we investigate here the effective application of [Tc(N)L(PNP)]+/0 technology (L=N-functionalized cysteine [O-,S-]; PNP=aminodiphosphine) to the preparation of target-specific radiopharmaceuticals. A series of 99mTc-nitrido complexes containing functionalized biotin ligands was prepared and their biological profile was determined. To minimize the steric and the electronic influences of the Tc-carrying complex on the biotin-avidin receptor interaction, the following N-functionalized cysteine-biotin derivatives were synthesized: (1) Biot-CysOSH; (2) Biot-Abu-CysOSH; (3) Biot-Abz-CysOSH; (4) Biot-L-(Ac)Lys-CysOSH; (5) Biot-D-(Ac)Lys-CysOSH; (6) Biot-Glu-CysOSH. The asymmetrical nitrido-Tc(V) 99g/99mTc(N)(Biot-X-CysOS)(PNP3) (X=spacer) complexes, where PNP3 was N,N-bis-[(dimethoxypropyl)phosphinoethyl] methoxy-ethylamine, were obtained by simultaneous addition of PNP3 and the relevant biotinylated ligand to a solution containing a 99mTc-nitrido precursor (yields >95%). In all cases, a mixture of syn- and anti isomers was observed. In vitro challenge experiments with glutathione and cysteine indicated that no transchelation reactions occurred. Assessment of the in vitro binding to avidin of the complexes revealed that only the complexes containing Biot-Abu-CysOS and Biot-Glu-CysOS ligand maintained a good affinity for the concentrator. Stability studies carried out in human and mouse plasma as well as in rat and mouse liver homogenate evidenced a rapid enzymatic degradation for the 99mTc(N)(Biot-Abu-CysOS)(PNP3) complex, whereas the 99mTc(N)(Biot-Glu-CysOS)(PNP3) one was stable in all conditions. Tissue biodistribution in normal Balb/C mice of the most stable candidate showed a rapid clearance both from the blood and the other tissues. The activity was eliminated both through the hepatobiliary system and the urinary tract

  11. Redox and zinc signalling pathways converging on protein tyrosine phosphatases.

    Science.gov (United States)

    Bellomo, Elisa; Hogstrand, Christer; Maret, Wolfgang

    2014-10-01

    Zinc ions, though redox-inert, have either pro-antioxidant or pro-oxidant functions at critical junctures in redox metabolism and redox signalling. They are released from cells and in cells, e.g. from metallothionein, a protein that transduces redox signals into zinc signals (1). The released zinc ions inhibit enzymes such as protein tyrosine phosphatases (PTPs), key regulatory enzymes of cellular phosphorylation signalling. The Ki(Zn) value for inhibition of receptor PTPB is 21pM (2). The binding is about as tight as the binding of zinc to zinc metalloenzymes and suggests tonic zinc inhibition. PTP1-B (PTPN1), an enzyme regulating the insulin and leptin receptors and involved in cancer and diabetes pathobiochemistry, has a Ki(Zn) value of about 5nM (3). Zinc ions bind to the enzyme in the closed conformation when additional metal-binding ligands are brought into the vicinity of the active site. In contrast, redox reactions target cysteines in the active sites of PTPs in the open conformation. This work provides a molecular basis how hydrogen peroxide and free zinc ions generated by growth factor signalling stimulate phosphorylation signalling differentially. (Supported by the Biotechnology and Biological Sciences Research Council UK, grant BB/K001442/1.). PMID:26461422

  12. Post-Translational Modification Biology of Glutamate Receptors and Drug Addiction

    OpenAIRE

    Mao, Li-Min; Guo, Ming-Lei; JIN, Dao-Zhong; Fibuch, Eugene E.; Choe, Eun Sang; Wang, John Q.

    2011-01-01

    Post-translational covalent modifications of glutamate receptors remain a hot topic. Early studies have established that this family of receptors, including almost all ionotropic and metabotropic glutamate receptor subtypes, undergoes active phosphorylation at serine, threonine, or tyrosine residues in their intracellular domains. Recent evidence identifies several glutamate receptor subtypes to be direct substrates for palmitoylation at cysteine residues. Other modifications such as ubiquiti...

  13. Evaluation of tyrosine kinase inhibitor combinations for glioblastoma therapy.

    Directory of Open Access Journals (Sweden)

    Avadhut D Joshi

    Full Text Available Glioblastoma multiforme (GBM is the most common intracranial cancer but despite recent advances in therapy the overall survival remains about 20 months. Whole genome exon sequencing studies implicate mutations in the receptor tyrosine kinase pathways (RTK for driving tumor growth in over 80% of GBMs. In spite of various RTKs being mutated or altered in the majority of GBMs, clinical studies have not been able to demonstrate efficacy of molecular targeted therapies using tyrosine kinase inhibitors in GBMs. Activation of multiple downstream signaling pathways has been implicated as a possible means by which inhibition of a single RTK has been ineffective in GBM. In this study, we sought a combination of approved drugs that would inhibit in vitro and in vivo growth of GBM oncospheres. A combination consisting of gefitinib and sunitinib acted synergistically in inhibiting growth of GBM oncospheres in vitro. Sunitinib was the only RTK inhibitor that could induce apoptosis in GBM cells. However, the in vivo efficacy testing of the gefitinib and sunitinib combination in an EGFR amplified/PTEN wild type GBM xenograft model revealed that gefitinib alone could significantly improve survival in animals whereas sunitinib did not show any survival benefit. Subsequent testing of the same drug combination in a different syngeneic glioma model that lacked EGFR amplification but was more susceptible to sunitinib in vitro demonstrated no survival benefit when treated with gefitinib or sunitinib or the gefitinib and sunitinib combination. Although a modest survival benefit was obtained in one of two animal models with EGFR amplification due to gefitinib alone, the addition of sunitinib, to test our best in vitro combination therapy, did not translate to any additional in vivo benefit. Improved targeted therapies, with drug properties favorable to intracranial tumors, are likely required to form effective drug combinations for GBM.

  14. Tyrosine-phosphorylation of AAV2 vectors and its consequences on viral intracellular trafficking and transgene expression

    International Nuclear Information System (INIS)

    We have documented that epidermal growth factor receptor protein tyrosine kinase (EGFR-PTK) signaling negatively affects intracellular trafficking and transduction efficiency of recombinant adeno-associated virus 2 (AAV2) vectors. Specifically, inhibition of EGFR-PTK signaling leads to decreased ubiquitination of AAV2 capsid proteins, which in turn, facilitates viral nuclear transport by limiting proteasome-mediated degradation of AAV2 vectors. In the present studies, we observed that AAV capsids can indeed be phosphorylated at tyrosine residues by EGFR-PTK in in vitro phosphorylation assays and that phosphorylated AAV capsids retain their structural integrity. However, although phosphorylated AAV vectors enter cells as efficiently as their unphosphorylated counterparts, their transduction efficiency is significantly reduced. This reduction is not due to impaired viral second-strand DNA synthesis since transduction efficiency of both single-stranded AAV (ssAAV) and self-complementary AAV (scAAV) vectors is decreased by ∼ 68% and ∼ 74%, respectively. We also observed that intracellular trafficking of tyrosine-phosphorylated AAV vectors from cytoplasm to nucleus is significantly decreased, which results from ubiquitination of AAV capsids followed by proteasome-mediated degradation, although downstream consequences of capsid ubiquitination may also be affected by tyrosine-phosphorylation. These studies provide new insights into the role of tyrosine-phosphorylation of AAV capsids in various steps in the virus life cycle, which has implications in the optimal use of recombinant AAV vectors in human gene therapy

  15. Uniform Orientation of Biotinylated Nanobody as an Affinity Binder for Detection of Bacillus thuringiensis (Bt) Cry1Ac Toxin

    Science.gov (United States)

    Li, Min; Zhu, Min; Zhang, Cunzheng; Liu, Xianjin; Wan, Yakun

    2014-01-01

    Nanobodies are the smallest natural fragments with useful properties such as high affinity, distinct paratope and high stability, which make them an ideal tool for detecting target antigens. In this study, we generated and characterized nanobodies against the Cry1Ac toxin and applied them in a biotin-streptavidin based double antibodies (nanobodies) sandwich-ELISA (DAS-ELISA) assay. After immunizing a camel with soluble Cry1Ac toxin, a phage displayed library was constructed to generate Nbs against the Cry1Ac toxin. Through successive rounds of affinity bio-panning, four nanobodies with greatest diversity in CDR3 sequences were obtained. After affinity determination and conjugating to HRP, two nanobodies with high affinity which can recognize different epitopes of the same antigen (Cry1Ac) were selected as capture antibody (Nb61) and detection antibody (Nb44). The capture antibody (Nb61) was biotinylated in vivo for directional immobilization on wells coated with streptavidin matrix. Both results of specificity analysis and thermal stability determination add support for reliability of the following DAS-ELISA with a minimum detection limit of 0.005 μg·mL−1 and a working range 0.010–1.0 μg·mL−1. The linear curve displayed an acceptable correlation coefficient of 0.9976. These results indicated promising applications of nanobodies for detection of Cry1Ac toxin with biotin-streptavidin based DAS-ELISA system. PMID:25474492

  16. Uniform Orientation of Biotinylated Nanobody as an Affinity Binder for Detection of Bacillus thuringiensis (Bt Cry1Ac Toxin

    Directory of Open Access Journals (Sweden)

    Min Li

    2014-12-01

    Full Text Available Nanobodies are the smallest natural fragments with useful properties such as high affinity, distinct paratope and high stability, which make them an ideal tool for detecting target antigens. In this study, we generated and characterized nanobodies against the Cry1Ac toxin and applied them in a biotin-streptavidin based double antibodies (nanobodies sandwich-ELISA (DAS-ELISA assay. After immunizing a camel with soluble Cry1Ac toxin, a phage displayed library was constructed to generate Nbs against the Cry1Ac toxin. Through successive rounds of affinity bio-panning, four nanobodies with greatest diversity in CDR3 sequences were obtained. After affinity determination and conjugating to HRP, two nanobodies with high affinity which can recognize different epitopes of the same antigen (Cry1Ac were selected as capture antibody (Nb61 and detection antibody (Nb44. The capture antibody (Nb61 was biotinylated in vivo for directional immobilization on wells coated with streptavidin matrix. Both results of specificity analysis and thermal stability determination add support for reliability of the following DAS-ELISA with a minimum detection limit of 0.005 μg·mL−1 and a working range 0.010–1.0 μg·mL−1. The linear curve displayed an acceptable correlation coefficient of 0.9976. These results indicated promising applications of nanobodies for detection of Cry1Ac toxin with biotin-streptavidin based DAS-ELISA system.

  17. Sensitive detection of platelet-specific antibodies with a modified MAIPA using biotinylated antibodies and streptavidin-coated beads.

    Science.gov (United States)

    Mörtberg, Anette; Meinke, Stephan; Berg, Petra; Killie, Mette Kjær; Kjeldsen-Kragh, Jens; Järås, Kerstin; Refsum, Erle; Höglund, Petter; Wikman, Agneta

    2016-07-01

    We have developed a modified monoclonal antibody immobilization of platelet antigens assay (MAIPA) with enhanced sensitivity in detecting antibodies against human platelet antigens (HPA), using biotinylated monoclonal antibodies, streptavidin-coated beads and detection by flow cytometry. The beads-MAIPA gave superior signal-to-noise resolution (>10-fold higher) for detection of anti-HPA-1a and anti-HPA-5b compared with the in-house standard MAIPA. Also, efficient and reproducible detection of anti-HPA-15 (CD109) was shown. The enhanced sensitivity was confirmed using WHO International Reference Reagents for anti-HPA-1a, anti-HPA-3a and anti-HPA-5b, which allowed comparison of detection endpoints with other laboratories. Finally, the beads-MAIPA was validated for quantification of anti-HPA-1a. The lower limit of quantification was 0.4IU/mL for beads-MAIPA, compared to 1IU/mL previously reported for standard MAIPA. Based on improved performance against all HPA-antibodies tested, the beads-MAIPA has replaced the standard MAIPA in our laboratory in diagnostics of conditions due to HPA-immunization, such as fetal and neonatal alloimmune thrombocytopenia (FNAIT). PMID:27059653

  18. Insulin rapidly stimulates phosphorylation of a 46-kDa membrane protein on tyrosine residues as well as phosphorylation of several soluble proteins in intact fat cells

    International Nuclear Information System (INIS)

    It is speculated that the transmission of an insulin signal across the plasma membrane of cells occurs through activation of the tyrosine-specific receptor kinase, autophosphorylation of the receptor, and subsequent phosphorylation of unidentified substrates in the cell. In an attempt to identify possible substrates, the authors labeled intact rat fat cells with [32P]orthophosphate and used an antiphosphotyrosine antibody to identify proteins that become phosphorylated on tyrosine residues in an insulin-stimulated way. In the membrane fraction of the fat cells, they found, in addition to the 95-kDa β-subunit of the receptor, a 46-kDa phosphoprotein that is phosphorylated exclusively on tyrosine residues. This protein is not immunoprecipitated by antibodies against different regions of the insulin receptor and its HPLC tryptic peptide map is different from the tryptic peptide map of the insulin receptor, suggesting that it is not derived from the receptor β-subunit. Insulin stimulates the tyrosine phosphorylation of the 46-kDa protein within 150 sec in the intact cell 3- to 4-fold in a dose-dependent way at insulin concentrations between 0.5 nM and 100 nM. Insulin (0.5 nM, 100 nM) stimulated within 2 min the 32P incorporation into a 116-kDa band, a 62 kDa band, and three bands between 45 kDa and 50 kDa 2- to 10-fold. They suggest that the 46-kDa membrane protein and possibly also the soluble proteins are endogenous substrates of the receptor tyrosine kinase in fat cells and that their phosphorylation is an early step in insulin signal transmission

  19. Simple Screening Method for Autoantigen Proteins Using the N-Terminal Biotinylated Protein Library Produced by Wheat Cell-Free Synthesis

    OpenAIRE

    Matsuoka, Kazuhiro; Komori, Hiroaki; Nose, Masato; Endo, Yaeta; Sawasaki, Tatsuya

    2010-01-01

    Autoimmune diseases are a heterogeneous group of diseases characterized by immune reactions against either a major or a limited number of the bodies own autoantigens, causing inflammation and damage to tissues and organs. Thus, identification of autoantigens is an important first step to understanding autoimmune diseases. Here we demonstrate a simple screening method for identification of autoantigens reacting with patient serum antibodies by combination of an N-terminal biotinylated protein ...

  20. Sodium-Dependent Multivitamin Transporter Gene Is Regulated at the Chromatin Level by Histone Biotinylation in Human Jurkat Lymphoblastoma Cells1–3

    OpenAIRE

    Zempleni, Janos; Gralla, Michael; Camporeale, Gabriela; Hassan, Yousef I.

    2009-01-01

    The sodium-dependent multivitamin transporter (SMVT) is essential for mediating and regulating biotin entry into mammalian cells. In cells, holocarboxylase synthetase (HCS) mediates covalent binding of biotin to histones; biotinylation of lysine-12 in histone H4 (K12BioH4) causes gene repression. Here we propose a novel role for HCS in sensing and regulating levels of biotin in eukaryotic cells. We hypothesize that nuclear translocation of HCS increases in response to biotin supplementation; ...

  1. Feeding Drosophila a biotin-deficient diet for multiple generations increases stress resistance and lifespan and alters gene expression and histone biotinylation patterns 1,2

    OpenAIRE

    Smith, Erin M; Hoi, Jia Tse; Eissenberg, Joel C.; Shoemaker, James D.; Neckameyer, Wendi S; Ilvarsonn, Anne M.; Harshman, Lawrence G.; Schlegel, Vicki L.; Zempleni, Janos

    2007-01-01

    Caloric restriction increases stress resistance and lifespan in Drosophila melanogaster and other species. The roles of individual nutrients in stress resistance and longevity are largely unknown. The vitamin biotin is a potential candidate for mediating these effects, given its known roles in stress signaling and gene regulation by epigenetic mechanisms, i.e., biotinylation of histones. Here, we tested the hypothesis that prolonged culture of Drosophila on biotin-deficient medium increases s...

  2. Development of a biotinylated broad-specificity single-chain variable fragment antibody and a sensitive immunoassay for detection of organophosphorus pesticides.

    Science.gov (United States)

    Zhao, Fengchun; Tian, Yuan; Wang, Huimin; Liu, Jiye; Han, Xiao; Yang, Zhengyou

    2016-09-01

    Organophosphorus pesticides (OPs) are the most widely used pesticides in agriculture, and OP residues have been broadly reported in food and environmental samples. The aim of this study is to develop a recombinant antibody-based broad-specificity immunoassay for OPs. A phage display library was prepared from a mouse pre-immunized with a generic immunogen of OPs, and a single-chain variable fragment (scFv) antibody was selected. The selected scFv antibody was fused with biotin acceptor domain (BAD) and overexpressed as an inclusion body in Escherichia coli BL21 (DE3). Then, the protein was refolded by stepwise urea gradient dialysis and biotinylated in vitro by E. coli biotin ligase (BirA). Subsequently, the scFv-BAD protein was purified from the biotinylated system with high yield (66.7 mg L(-1)) and confirmed by SDS-PAGE and Western blot. Based on the biotinylated scFv-BAD, a sensitive and broad-specificity competitive indirect enzyme-linked immunosorbent assay (ciELISA) for detection of OPs was developed. The cross-reactivity (CR) studies demonstrated that the ciELISA described here exhibited the broadest detection spectrum for OPs up to now, and 30 OPs could be determined with 50 % inhibition value (IC50) values ranging from 19.4 to 515.2 ng mL(-1). Moreover, the developed ciELISA was used for the recovery study of the spiked samples and showed satisfactory recoveries. Graphical Abstract Schematic diagram of the development of biotinylated broad-specificity single-chain variable fragment antibody-based immunoassay for organophosphorus pesticides. PMID:27411546

  3. Simultaneous extraction from clinical biopsies of high-molecular-weight DNA and RNA: comparative characterization by biotinylated and 32P-labeled probes on Southern and Northern blots

    International Nuclear Information System (INIS)

    A method for efficient simultaneous extraction of high-molecular-weight DNA and RNA from solid mammalian tissues including clinical biopsies is described. It is based on the disruption and subsequent melting of deep frozen tissue in the presence of frozen phenol and nucleic acid extraction buffer; this allows for simultaneous disruption of tissue and inactivation of nucleases. The yield is about 0.7-5.8 mg of DNA and 0.5-8.1 mg of total RNA/g of tissue depending upon the tissue type; this is higher than the yield of other methods tested. Analysis of total RNA by denaturing gel electrophoresis, and of DNA and poly(A)+ RNA by Southern and Northern blot hybridization using 32P and biotinylated probes, indicated that c-Ha-ras gene and its transcripts were undegraded. Biotinylated and 32P probes had approximately the same sensitivity in detecting nucleic acids on Southern and Northern blots. This extraction procedure is simple and, when used with biotinylated probes, is rapid, inexpensive, and nonhazardous. The methodology can be modified for use with other clinical samples and cells grown in culture

  4. Effects of platelet inhibitors on propyl gallate-induced platelet aggregation, protein tyrosine phosphorylation, and platelet factor 3 activation.

    Science.gov (United States)

    Xiao, Hongyan; Kovics, Richard; Jackson, Van; Remick, Daniel G

    2004-04-01

    Propyl gallate (PG) is a platelet agonist characterized by inducing platelet aggregation, protein tyrosine phosphorylation, and platelet factor 3 activity. The mechanisms of platelet activation following PG stimulation were examined by pre-incubating platelets with well-defined platelet inhibitors using platelet aggregation, protein tyrosine phosphorylation, activated plasma clotting time, and annexin V binding by flow cytometry. PG-induced platelet aggregation and tyrosine phosphorylation of multiple proteins were substantially abolished by aspirin, apyrase, and abciximab (c7E3), suggesting that PG is associated with activation of platelet cyclooxygenase 1, adenosine phosphate receptors, and glycoprotein IIb/IIIa, respectively. The phosphorylation of the cytoskeletal enzyme pp60(c-src) increased following PG stimulation, but was blunted by pre-incubation of platelets with aspirin, apyrase, and c7E3, suggesting that tyrosine kinase is important for the signal transduction of platelet aggregation. Propyl gallate also activates platelet factor 3 by decreasing the platelet coagulation time and increasing platelet annexin V binding. Platelet incubation with aspirin, apyrase, and c7E3 did not alter PG-induced platelet coagulation and annexin V binding. The results suggest that platelet factor 3 activation and membrane phosphotidylserine expression were not involved with activation of platelet cyclooxygenase, adenosine phosphate receptors, and glycoprotein IIb/IIIa. PG is unique in its ability to stimulate platelet aggregation and coagulation simultaneously, and platelet inhibitors in this study affect only platelet aggregation but not platelet coagulation. PMID:15060414

  5. A rapid lateral flow immunoassay for the detection of tyrosine phosphatase-like protein IA-2 autoantibodies in human serum.

    Directory of Open Access Journals (Sweden)

    Ingrid Kikkas

    Full Text Available Type 1 diabetes (T1D results from the destruction of pancreatic insulin-producing beta cells and is strongly associated with the presence of islet autoantibodies. Autoantibodies to tyrosine phosphatase-like protein IA-2 (IA-2As are considered to be highly predictive markers of T1D. We developed a novel lateral flow immunoassay (LFIA based on a bridging format for the rapid detection of IA-2As in human serum samples. In this assay, one site of the IA-2As is bound to HA-tagged-IA-2, which is subsequently captured on the anti-HA-Tag antibody-coated test line on the strip. The other site of the IA-2As is bound to biotinylated IA-2, allowing the complex to be visualized using colloidal gold nanoparticle-conjugated streptavidin. For this study, 35 serum samples from T1D patients and 44 control sera from non-diabetic individuals were analyzed with our novel assay and the results were correlated with two IA-2A ELISAs. Among the 35 serum samples from T1D patients, the IA-2A LFIA, the in-house IA-2A ELISA and the commercial IA-2A ELISA identified as positive 21, 29 and 30 IA-2A-positive sera, respectively. The major advantages of the IA-2A LFIA are its rapidity and simplicity.

  6. Characteristics and overall survival of EGFR mutation-positive non-small cell lung cancer treated with EGFR tyrosine kinase inhibitors: a retrospective analysis for 1660 Japanese patients

    Science.gov (United States)

    Inoue, Akira; Yoshida, Kazushi; Morita, Satoshi; Imamura, Fumio; Seto, Takashi; Okamoto, Isamu; Nakagawa, Kazuhiko; Yamamoto, Nobuyuki; Muto, Satoshi; Fukuoka, Masahiro

    2016-01-01

    Background The Japan Guidelines of Lung Cancer Therapy recommend epidermal growth factor receptor-tyrosine kinase inhibitors as a first-line therapy for advanced/recurrent non-small cell lung cancer patients with epidermal growth factor receptor mutation. Although survival periods in recent reports of epidermal growth factor receptor-tyrosine kinase inhibitor treatment have been getting longer, the reasons why are unclear. We investigated the survival, prognostic factors and real-world treatment of non-small cell lung cancer patients with epidermal growth factor receptor mutation in clinical practice. Methods Non-small cell lung cancer patients (n = 1660) who started first-line treatment from January 2008 to December 2012 were enrolled. Patients were diagnosed with epidermal growth factor receptor mutation-positive advanced/recurrent non-small cell lung cancer by histology or cytology samples. The primary objective was to estimate overall survival. The secondary objectives were to determine prognostic factors, real-world treatment patterns and efficacy of gefitinib treatment. We calculated the treatment exposure rate for each treatment category using the following formula: exposure rate = person-years for the treatment category/total person-years × 100. Results The median overall survival was 30.8 months. Sex, age, histology, epidermal growth factor receptor mutation type, clinical stage and performance status affected overall survival. The exposure rates for all epidermal growth factor receptor-tyrosine kinase inhibitors, gefitinib and platinum-doublet chemotherapy were 62.1, 46.4 and 8.5% respectively. Overall 56.1% of patients were administered gefitinib as first-line therapy, and 39.0% were treated with ≥2 epidermal growth factor receptor-tyrosine kinase inhibitor regimens. The median progression-free survival in the first-line gefitinib group was 11.4 months. Factors affecting prognosis were sex, histology, clinical stage and performance status. Conclusion

  7. 中国北京汉族人群和日本东京人群ROR2基因单核苷酸多态性比较%Comparison of minor allele frequency and haplotype frequencies for single nucleotide polymorphisms in receptor tyrosine kinase-like orphan receptor 2 gene using HapMap data from Han Chinese in Beijing (CHB) and Japanese in Tokyo (JPT)

    Institute of Scientific and Technical Information of China (English)

    王红; 赵凯平

    2011-01-01

    Objective Single nucleotide polymorphisms(SNPs) in receptor tyrosine kinaselike orphan receptor 2 (ROR2) gene were analyzed and compared between Han Chinese in Beijing(CHB) and Japanese in Tokyo(JPT) using the HapMap data,to provide basis for SNP determination.ROR2 gene related etiologic studies were conducted in the above mentioned two populations.Methods Monotonic and un-monotonic SNPs of ROR2 gene were distinguished by Haploviewprogram.Minor allele frequency (MAF),haplotype blocks and haplotype frequencies were analyzed ineligible SNPs and tag SNPs respectively with genotyping call rate >80%,MAF>1%,H-Wequilibrium (P>0.01) and no gender difference (P>0.05).Tag SNPs were determined under thecriteria of r2≥0.8 or logarithm of the odd score (LOD) ≥3 for pairwise eligible SNPs in CHB and JPT.Common tag SNPs for CHB and JPT were directly reported by Haploview program or being identified from those which were higly related to tag SNPs reported by haploview program under SPSS 13.0 software.Results A total of 404 common SNPs were provided for both CHB and JPT samples by HapMap,where 101 common monotonic SNPs between CHB and JPT had the common minor alleles.The common SNPs between CHB and JPT were 257.In the 257 common eligible SNPs,224 (87.2%) had common minor alleles.Among the 18 and 27 haplotype blocks identified in 257common eligible SNPs between CHB and JPT,except for 2 independent haplotype blocks identified only in JPT.Other haplotype blocks between CHB and JPT were overlapped partly or completely.A number of 50 common tag SNPs between CHB and JPT were determined and the proportions in CHB and JPT were 64.9% and 70.4% respectively.Conclusion Analysis of HapMap data provided an opportunity to avoid monotonic SNPs that had been included in ROR2 gene related etiologic studies.SNPs in ROR2 gene had common features in alleles,MAF,haplotype blocks and haplotype frequencies between CHB and JPT populations,which were consistent with the geographic and

  8. Protein tyrosine adduct in humans self-poisoned by chlorpyrifos

    International Nuclear Information System (INIS)

    Studies of human cases of self-inflicted poisoning suggest that chlorpyrifos oxon reacts not only with acetylcholinesterase and butyrylcholinesterase but also with other blood proteins. A favored candidate is albumin because in vitro and animal studies have identified tyrosine 411 of albumin as a site covalently modified by organophosphorus poisons. Our goal was to test this proposal in humans by determining whether plasma from humans poisoned by chlorpyrifos has adducts on tyrosine. Plasma samples from 5 self-poisoned humans were drawn at various time intervals after ingestion of chlorpyrifos for a total of 34 samples. All 34 samples were analyzed for plasma levels of chlorpyrifos and chlorpyrifos oxon (CPO) as a function of time post-ingestion. Eleven samples were analyzed for the presence of diethoxyphosphorylated tyrosine by mass spectrometry. Six samples yielded diethoxyphosphorylated tyrosine in pronase digests. Blood collected as late as 5 days after chlorpyrifos ingestion was positive for CPO-tyrosine, consistent with the 20-day half-life of albumin. High plasma CPO levels did not predict detectable levels of CPO-tyrosine. CPO-tyrosine was identified in pralidoxime treated patients as well as in patients not treated with pralidoxime, indicating that pralidoxime does not reverse CPO binding to tyrosine in humans. Plasma butyrylcholinesterase was a more sensitive biomarker of exposure than adducts on tyrosine. In conclusion, chlorpyrifos oxon makes a stable covalent adduct on the tyrosine residue of blood proteins in humans who ingested chlorpyrifos. - Highlights: • Chlorpyrifos-poisoned patients have adducts on protein tyrosine. • Diethoxyphosphate-tyrosine does not lose an alkyl group. • Proteins in addition to AChE and BChE are modified by organophosphates

  9. Protein tyrosine adduct in humans self-poisoned by chlorpyrifos

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bin, E-mail: binli@unmc.edu [Eppley Institute, University of Nebraska Medical Center, Omaha, NE 68198-5950 (United States); Eyer, Peter, E-mail: peter.eyer@lrz.uni-muenchen.de [Walther-Straub-Institut Für Pharmakologie und Toxikologie, Ludwig-Maximilians-Universität München, 80336 München (Germany); Eddleston, Michael, E-mail: M.Eddleston@ed.ac.uk [Clinical Pharmacology Unit, University of Edinburgh, Edinburgh (United Kingdom); Jiang, Wei, E-mail: wjiang@unmc.edu [Eppley Institute, University of Nebraska Medical Center, Omaha, NE 68198-5950 (United States); Schopfer, Lawrence M., E-mail: lmschopf@unmc.edu [Eppley Institute, University of Nebraska Medical Center, Omaha, NE 68198-5950 (United States); Lockridge, Oksana, E-mail: olockrid@unmc.edu [Eppley Institute, University of Nebraska Medical Center, Omaha, NE 68198-5950 (United States)

    2013-06-15

    Studies of human cases of self-inflicted poisoning suggest that chlorpyrifos oxon reacts not only with acetylcholinesterase and butyrylcholinesterase but also with other blood proteins. A favored candidate is albumin because in vitro and animal studies have identified tyrosine 411 of albumin as a site covalently modified by organophosphorus poisons. Our goal was to test this proposal in humans by determining whether plasma from humans poisoned by chlorpyrifos has adducts on tyrosine. Plasma samples from 5 self-poisoned humans were drawn at various time intervals after ingestion of chlorpyrifos for a total of 34 samples. All 34 samples were analyzed for plasma levels of chlorpyrifos and chlorpyrifos oxon (CPO) as a function of time post-ingestion. Eleven samples were analyzed for the presence of diethoxyphosphorylated tyrosine by mass spectrometry. Six samples yielded diethoxyphosphorylated tyrosine in pronase digests. Blood collected as late as 5 days after chlorpyrifos ingestion was positive for CPO-tyrosine, consistent with the 20-day half-life of albumin. High plasma CPO levels did not predict detectable levels of CPO-tyrosine. CPO-tyrosine was identified in pralidoxime treated patients as well as in patients not treated with pralidoxime, indicating that pralidoxime does not reverse CPO binding to tyrosine in humans. Plasma butyrylcholinesterase was a more sensitive biomarker of exposure than adducts on tyrosine. In conclusion, chlorpyrifos oxon makes a stable covalent adduct on the tyrosine residue of blood proteins in humans who ingested chlorpyrifos. - Highlights: • Chlorpyrifos-poisoned patients have adducts on protein tyrosine. • Diethoxyphosphate-tyrosine does not lose an alkyl group. • Proteins in addition to AChE and BChE are modified by organophosphates.

  10. Gab2 is phosphorylated on tyrosine upon interleukin-2/interleukin-15 stimulation in mycosis-fungoides-derived tumor T cells and associates inducibly with SHP-2 and Stat5a

    DEFF Research Database (Denmark)

    Brockdorff, J L; Gu, H; Mustelin, T;

    2001-01-01

    Cutaneous T cell lymphomas (CTCLs) often show abnormal interleukin-2 (IL-2) receptor signaling. In this study, we investigated the role of Gab2, a recently identified adaptor molecule involved in IL-2 receptor signaling in CTCLs. We show that Gab2 was transiently phosphorylated by tyrosine in human...

  11. Inhibitor of the tyrosine phosphatase STEP reverses cognitive deficits in a mouse model of Alzheimer's disease.

    Science.gov (United States)

    Xu, Jian; Chatterjee, Manavi; Baguley, Tyler D; Brouillette, Jonathan; Kurup, Pradeep; Ghosh, Debolina; Kanyo, Jean; Zhang, Yang; Seyb, Kathleen; Ononenyi, Chimezie; Foscue, Ethan; Anderson, George M; Gresack, Jodi; Cuny, Gregory D; Glicksman, Marcie A; Greengard, Paul; Lam, TuKiet T; Tautz, Lutz; Nairn, Angus C; Ellman, Jonathan A; Lombroso, Paul J

    2014-08-01

    STEP (STriatal-Enriched protein tyrosine Phosphatase) is a neuron-specific phosphatase that regulates N-methyl-D-aspartate receptor (NMDAR) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) trafficking, as well as ERK1/2, p38, Fyn, and Pyk2 activity. STEP is overactive in several neuropsychiatric and neurodegenerative disorders, including Alzheimer's disease (AD). The increase in STEP activity likely disrupts synaptic function and contributes to the cognitive deficits in AD. AD mice lacking STEP have restored levels of glutamate receptors on synaptosomal membranes and improved cognitive function, results that suggest STEP as a novel therapeutic target for AD. Here we describe the first large-scale effort to identify and characterize small-molecule STEP inhibitors. We identified the benzopentathiepin 8-(trifluoromethyl)-1,2,3,4,5-benzopentathiepin-6-amine hydrochloride (known as TC-2153) as an inhibitor of STEP with an IC50 of 24.6 nM. TC-2153 represents a novel class of PTP inhibitors based upon a cyclic polysulfide pharmacophore that forms a reversible covalent bond with the catalytic cysteine in STEP. In cell-based secondary assays, TC-2153 increased tyrosine phosphorylation of STEP substrates ERK1/2, Pyk2, and GluN2B, and exhibited no toxicity in cortical cultures. Validation and specificity experiments performed in wild-type (WT) and STEP knockout (KO) cortical cells and in vivo in WT and STEP KO mice suggest specificity of inhibitors towards STEP compared to highly homologous tyrosine phosphatases. Furthermore, TC-2153 improved cognitive function in several cognitive tasks in 6- and 12-mo-old triple transgenic AD (3xTg-AD) mice, with no change in beta amyloid and phospho-tau levels. PMID:25093460

  12. Role of Striatal-Enriched Tyrosine Phosphatase in Neuronal Function.

    Science.gov (United States)

    Kamceva, Marija; Benedict, Jessie; Nairn, Angus C; Lombroso, Paul J

    2016-01-01

    Striatal-enriched protein tyrosine phosphatase (STEP) is a CNS-enriched protein implicated in multiple neurologic and neuropsychiatric disorders. STEP regulates key signaling proteins required for synaptic strengthening as well as NMDA and AMPA receptor trafficking. Both high and low levels of STEP disrupt synaptic function and contribute to learning and behavioral deficits. High levels of STEP are present in human postmortem samples and animal models of Alzheimer's disease, Parkinson's disease, and schizophrenia and in animal models of fragile X syndrome. Low levels of STEP activity are present in additional disorders that include ischemia, Huntington's chorea, alcohol abuse, and stress disorders. Thus the current model of STEP is that optimal levels are required for optimal synaptic function. Here we focus on the role of STEP in Alzheimer's disease and the mechanisms by which STEP activity is increased in this illness. Both genetic lowering of STEP levels and pharmacological inhibition of STEP activity in mouse models of Alzheimer's disease reverse the biochemical and cognitive abnormalities that are present. These findings suggest that STEP is an important point for modulation of proteins required for synaptic plasticity. PMID:27190655

  13. Protein tyrosine phosphatases expression during development of mouse superior colliculus.

    Science.gov (United States)

    Reinhard, Jacqueline; Horvat-Bröcker, Andrea; Illes, Sebastian; Zaremba, Angelika; Knyazev, Piotr; Ullrich, Axel; Faissner, Andreas

    2009-12-01

    Protein tyrosine phosphatases (PTPs) are key regulators of different processes during development of the central nervous system. However, expression patterns and potential roles of PTPs in the developing superior colliculus remain poorly investigated. In this study, a degenerate primer-based reverse transcription-polymerase chain reaction (RT-PCR) approach was used to isolate seven different intracellular PTPs and nine different receptor-type PTPs (RPTPs) from embryonic E15 mouse superior colliculus. Subsequently, the expression patterns of 11 PTPs (TC-PTP, PTP1C, PTP1D, PTP-MEG2, PTP-PEST, RPTPJ, RPTPε, RPTPRR, RPTPσ, RPTPκ and RPTPγ) were further analyzed in detail in superior colliculus from embryonic E13 to postnatal P20 stages by quantitative real-time RT-PCR, Western blotting and immunohistochemistry. Each of the 11 PTPs exhibits distinct spatiotemporal regulation of mRNAs and proteins in the developing superior colliculus suggesting their versatile roles in genesis of neuronal and glial cells and retinocollicular topographic mapping. At E13, additional double-immunohistochemical analysis revealed the expression of PTPs in collicular nestin-positive neural progenitor cells and RC-2-immunoreactive radial glia cells, indicating the potential functional importance of PTPs in neurogenesis and gliogenesis. PMID:19727691

  14. Construction of a biotinylated cameloid-like antibody for lable-free detection of apolipoprotein B-100.

    Science.gov (United States)

    Li, Henan; Yan, Junrong; Ou, Weijun; Liu, Hong; Liu, Songqin; Wan, Yakun

    2015-02-15

    Nanobodies (Nbs), also known as the variable domain of the heavy-chain-only antibody (VHH), are single-domain antigen-binding fragments derived from heavy-chain antibodies that occur naturally in sera of camelids. Due to their unique properties of small size (15 kD), intrinsic stability, high affinity and specificity, Nbs are suitable for detecting clinical relevant antigens. Apolipoprotein B-100 (ApoB-100) is a highly predictive marker for coronary artery disease (CAD), which is frequently detected in clinical diagnosis. Herein, we successfully obtained anti-ApoB-100 Nbs for the first time and further fabricated a label-free and sensitive immunosensor for ApoB-100 based on isolated anti-ApoB-100 nanobody (Nb) using the electrochemical impedance spectroscopy (EIS) technique. We have generated an immunized phage display library against ApoB-100 and isolated four anti-ApoB-100 Nbs with high affinity and stability. The Nb with the highest affinity was biotinylated based on in vivo BirA system. Further, we developed a label-free electrochemical impedance immunosensor for ApoB-100 using this anti-ApoB-100 Nb. The attachment of ApoB-100 onto the anti-ApoB-100 Nb-immobilized sensing layer led to the increased electron-transfer resistance, which was proportional to ApoB-100 concentration in the range from 0.05 to 5 ng mL(-1) with a detection limit of 0.03 ng mL(-1). This proposed immunosensor revealed high specificity to detect ApoB-100, acceptable intra-assay precision and good stability, functioning as a feasible technique for CAD diagnosis. PMID:25203942

  15. Molecular predictors of response to tyrosine kinase inhibitors in patients with Non-Small-Cell Lung Cancer

    OpenAIRE

    Murray Samuel; Karavasilis Vasilios; Bobos Mattheos; Razis Evangelia; Papadopoulos Savvas; Christodoulou Christos; Kosmidis Paris; Fountzilas George

    2012-01-01

    Abstract Introduction Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have become a treatment option in non-small-cell lung cancer (NSCLC) patients. However, despite their use in this disease, a significant number of patients will eventually develop resistance and relapse. In this study, we aimed to characterize several molecular events involved in potential resistance mechanisms to anti-EGFR treatment and correlate our findings with clinical outcome. Material and me...

  16. Inhibition of Intrahepatic Bile Duct Dilation of the Polycystic Kidney Rat with a Novel Tyrosine Kinase Inhibitor Gefitinib

    OpenAIRE

    Sato, Yasunori; Harada, Kenichi; Furubo, Shinichi; Kizawa, Kazuo; Sanzen, Takahiro; Yasoshima, Mitsue; Ozaki, Satoru; Isse, Kumiko; Sasaki, Motoko; Nakanuma, Yasuni

    2006-01-01

    The polycystic kidney (PCK) rat represents a liver and kidney cyst pathology corresponding to Caroli’s disease with congenital hepatic fibrosis and autosomal recessive polycystic kidney disease. We previously reported that an epidermal growth factor receptor tyrosine kinase inhibitor, gefitinib (Iressa), significantly inhibited the abnormal growth of biliary epithelial cells of PCK rats in vitro. This study investigated the effects of gefitinib on cyst pathogenesis of the PCK rat both in vitr...

  17. Regulation of Alternative Macrophage Activation in the Liver following Acetaminophen Intoxication by Stem Cell-Derived Tyrosine Kinase

    OpenAIRE

    Carol R. Gardner; Hankey, Pamela; Mishin, Vladimir; Francis, Mary; Yu, Shan; Laskin, Jeffrey D.; Laskin, Debra L.

    2012-01-01

    Stem cell-derived tyrosine kinase (STK) is a transmembrane receptor reported to play a role in macrophage switching from a classically activated/proinflammatory phenotype to an alternatively activated/wound repair phenotype. In the present studies, STK−/− mice were used to assess the role of STK in acetaminophen-induced hepatotoxicity as evidence suggests that the pathogenic process involves both of these macrophage subpopulations. In wild type mice, centrilobular hepatic necrosis and increas...

  18. Eps15R is a tyrosine kinase substrate with characteristics of a docking protein possibly involved in coated pits-mediated internalization

    DEFF Research Database (Denmark)

    Coda, L; Salcini, A E; Confalonieri, S;

    1998-01-01

    , and 76 kDa were specifically recognized by anti-eps15R sera. The 125-kDa species is a bona fide product of the eps15R gene, whereas p108 and p76 are most likely products of alternative splicing events. Eps15R protein(s) are tyrosine-phosphorylated following epidermal growth factor receptor activation...

  19. Review of current classification, molecular alterations, and tyrosine kinase inhibitor therapies in myeloproliferative disorders with hypereosinophilia

    Directory of Open Access Journals (Sweden)

    Havelange V

    2013-08-01

    Full Text Available Violaine Havelange,1,2 Jean-Baptiste Demoulin1 1de Duve Institute, Université catholique de Louvain, Brussels, Belgium; 2Department of Hematology, Cliniques universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium Abstract: Recent advances in our understanding of the molecular mechanisms underlying hypereosinophilia have led to the development of a 'molecular' classification of myeloproliferative disorders with eosinophilia. The revised 2008 World Health Organization classification of myeloid neoplasms included a new category called “myeloid and lymphoid neoplasms with eosinophilia and abnormalities of PDGFRA, PDGFRB or FGFR1.” Despite the molecular heterogeneity of PDGFR (platelet-derived growth factor receptor rearrangements, tyrosine kinase inhibitors at low dose induce rapid and complete hematological remission in the majority of these patients. Other kinase inhibitors are promising. Further discoveries of new molecular alterations will direct the development of new specific inhibitors. In this review, an update of the classifications of myeloproliferative disorders associated with hypereosinophilia is discussed together with open and controversial questions. Molecular mechanisms and promising results of tyrosine kinase inhibitor treatments are reviewed. Keywords: hypereosinophilia, classification, myeloproliferative disorders, molecular alterations, tyrosine kinase inhibitor

  20. Tyrosine Kinase Inhibitors Induced Thyroid Dysfunction: A Review of Its Incidence, Pathophysiology, Clinical Relevance, and Treatment

    Directory of Open Access Journals (Sweden)

    Hala Ahmadieh

    2013-01-01

    Full Text Available Tyrosine kinase inhibitors (TKI belong to a new class of molecular multitargeted anticancer therapy which targets different growth factor receptors and hence attenuates cancer cell survival and growth. Since their introduction as adjunct treatment for renal cell carcinoma and gastrointestinal stromal tumors (GIST, a number of reports have demonstrated that TKI can induce thyroid dysfunction which was especially more common with sunitinib maleate. Many mechanisms with respect to this adverse effect of tyrosine kinase inhibitors have been proposed including their induction of thyroiditis, capillary regression in the thyroid gland, antithyroid peroxidase antibody production, and their ability to decrease iodine uptake by the thyroid gland. Of interest is the observation that TKI-induced thyroid dysfunction may actually be protective as it was shown to improve overall survival, and it was suggested that it may have a prognostic value. Followup on thyroid function tests while patients are maintained on tyrosine kinase inhibitor is strongly recommended. When thyroid dysfunction occurs, appropriate treatment should be individualized depending on patients symptoms and thyroid stimulating hormone level.

  1. QSAR and molecular docking studies on oxindole derivatives as VEGFR-2 tyrosine kinase inhibitors.

    Science.gov (United States)

    Kang, Cong-Min; Liu, Dong-Qing; Zhao, Xu-Hao; Dai, Ying-Jie; Cheng, Jia-Gao; Lv, Ying-Tao

    2016-01-01

    The three-dimensional quantitative structure-activity relationships (3D-QSAR) were established for 30 oxindole derivatives as vascular endothelial growth factor receptor-2 (VEGFR-2) tyrosine kinase inhibitors by using comparative molecular field analysis (CoMFA) and comparative similarity indices analysis comparative molecular similarity indices analysis (CoMSIA) techniques. With the CoMFA model, the cross-validated value (q(2)) was 0.777, the non-cross-validated value (R(2)) was 0.987, and the external cross-validated value ([Formula: see text]) was 0.72. And with the CoMSIA model, the corresponding q(2), R(2) and [Formula: see text] values were 0.710, 0.988 and 0.78, respectively. Docking studies were employed to bind the inhibitors into the active site to determine the probable binding conformation. The binding mode obtained by molecular docking was in good agreement with the 3D-QSAR results. Based on the QSAR models and the docking binding mode, a set of new VEGFR-2 tyrosine kinase inhibitors were designed, which showed excellent predicting inhibiting potencies. The result revealed that both QSAR models have good predictive capability to guide the design and structural modification of homologic compounds. It is also helpful for further research and development of new VEGFR-2 tyrosine kinase inhibitors. PMID:26416217

  2. 运动训练对脊髓损伤大鼠脊髓内BDNF及其受体TrkB表达的影响%Effects of Exercise on Expressions of Brain-Derived Neurotrophic Factor and Tyrosine Kinase Receptor B in Injured Spinal Cord of Rats

    Institute of Scientific and Technical Information of China (English)

    贺晓玉

    2014-01-01

    目的:研究运动训练对脊髓损伤(SCI)大鼠脊髓内脑源性神经营养因子(BDNF)及其酪氨酸激酶受体B(TrkB)表达的影响。方法24只SD大鼠随机均分为假手术组、损伤对照组和运动训练组。采用通用型脊髓打击器建立T10 SCI大鼠模型。运动训练组于损伤后1周起对大鼠进行4周运动训练,假手术组和损伤对照组不进行运动训练。采用BBB评分观察损伤前及损伤后第1~5周大鼠后肢运动功能的变化。运动训练结束后取大鼠T12~L1节段脊髓,免疫组化结合图像平均光密度分析观察脊髓组织BDNF和TrkB的表达及分布,Western blot检测脊髓内BDNF和TrkB蛋白含量。结果损伤前,3组大鼠BBB评分为21.00分。损伤后,损伤对照组及运动训练组BBB评分均低于假手术组(均P<0.05)。损伤3周后运动训练组BBB评分高于损伤对照组(P<0.05)。BDNF、TrkB免疫反应阳性产物均多分布于脊髓前角、脊髓后角及中央管周围;运动训练组BDNF、TrkB阳性染色颗粒均增多,平均光密度值均高于假手术组和损伤对照组(均P<0.05)。运动训练组大鼠脊髓内BDNF及TrkB的表达高于假手术组和损伤对照组。结论运动训练能诱导SCI大鼠脊髓内BDNF及其受体TrkB表达,促进其运动功能恢复。%Objective To investigate the effects of exercise on expressions of brain-derived neurotrophic factor (BDNF) and tyrosine kinase receptor B (TrkB) in spinal cord of spinal cord injury (SCI) rats. Methods Spinal cord injury models were produced by universal spinal cord impact system. Twenty-four Sprague-Dawley rats were randomly divided into 3 groups, exercise group (SCI-induction and exercises, n=8), control group (SCI-induction without exercises,n=8) and sham-operation group (no operation, without SCI nor exercises, n=8). Exercise training began from the 7th day after injury for 4 weeks. The locomotor function was assessed by Basso

  3. Redox-dependent regulation of epidermal growth factor receptor signaling.

    Science.gov (United States)

    Heppner, David E; van der Vliet, Albert

    2016-08-01

    Tyrosine phosphorylation-dependent cell signaling represents a unique feature of multicellular organisms, and is important in regulation of cell differentiation and specialized cell functions. Multicellular organisms also contain a diverse family of NADPH oxidases (NOXs) that have been closely linked with tyrosine kinase-based cell signaling and regulate tyrosine phosphorylation via reversible oxidation of cysteine residues that are highly conserved within many proteins involved in this signaling pathway. An example of redox-regulated tyrosine kinase signaling involves the epidermal growth factor receptor (EGFR), a widely studied receptor system with diverse functions in normal cell biology as well as pathologies associated with oxidative stress such as cancer. The purpose of this Graphical Redox Review is to highlight recently emerged concepts with respect to NOX-dependent regulation of this important signaling pathway. PMID:26722841

  4. Quantitation of multisite EGF receptor phosphorylation using mass spectrometry and a novel normalization approach

    DEFF Research Database (Denmark)

    Erba, Elisabetta Boeri; Matthiesen, Rune; Bunkenborg, Jakob; Schulze, Waltraud X; Di Stefano, Paola; Cabodi, Sara; Tarone, Guido; Defilippi, Paola; Jensen, Ole N

    2007-01-01

    Using stable isotope labeling and mass spectrometry, we performed a sensitive, quantitative analysis of multiple phosphorylation sites of the epidermal growth factor (EGF) receptor. Phosphopeptide detection efficiency was significantly improved by using the tyrosine phosphatase inhibitor sodium...

  5. PTPRT regulates the interaction of Syntaxin-binding protein 1 with Syntaxin 1 through dephosphorylation of specific tyrosine residue

    International Nuclear Information System (INIS)

    Highlights: •PTPRT is a brain-specific, expressed, protein tyrosine phosphatase. •PTPRT regulated the interaction of Syntaxin-binding protein 1 with Syntaxin 1. •PTPRT dephosphorylated the specific tyrosine residue of Syntaxin-binding protein 1. •Dephosphorylation of Syntaxin-binding protein 1 enhanced the interaction with Syntaxin 1. •PTPRT appears to regulate the fusion of synaptic vesicle through dephosphorylation. -- Abstract: PTPRT (protein tyrosine phosphatase receptor T), a brain-specific tyrosine phosphatase, has been found to regulate synaptic formation and development of hippocampal neurons, but its regulation mechanism is not yet fully understood. Here, Syntaxin-binding protein 1, a key component of synaptic vesicle fusion machinery, was identified as a possible interaction partner and an endogenous substrate of PTPRT. PTPRT interacted with Syntaxin-binding protein 1 in rat synaptosome, and co-localized with Syntaxin-binding protein 1 in cultured hippocampal neurons. PTPRT dephosphorylated tyrosine 145 located around the linker between domain 1 and 2 of Syntaxin-binding protein 1. Syntaxin-binding protein 1 directly binds to Syntaxin 1, a t-SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) protein, and plays a role as catalysts of SNARE complex formation. Syntaxin-binding protein 1 mutant mimicking non-phosphorylation (Y145F) enhanced the interaction with Syntaxin 1 compared to wild type, and therefore, dephosphorylation of Syntaxin-binding protein 1 appeared to be important for SNARE-complex formation. In conclusion, PTPRT could regulate the interaction of Syntaxin-binding protein 1 with Syntaxin 1, and as a result, the synaptic vesicle fusion appeared to be controlled through dephosphorylation of Syntaxin-binding protein 1

  6. Differential evolutionary wiring of the tyrosine kinase Btk.

    Directory of Open Access Journals (Sweden)

    Hossain M Nawaz

    Full Text Available BACKGROUND: A central question within biology is how intracellular signaling pathways are maintained throughout evolution. Btk29A is considered to be the fly-homolog of the mammalian Bruton's tyrosine kinase (Btk, which is a non-receptor tyrosine-kinase of the Tec-family. In mammalian cells, there is a single transcript splice-form and the corresponding Btk-protein plays an important role for B-lymphocyte development with alterations within the human BTK gene causing the immunodeficiency disease X-linked agammaglobulinemia in man and a related disorder in mice. In contrast, the Drosophila Btk29A locus encodes two splice-variants, where the type 2-form is the more related to the mammalian Btk gene product displaying more than 80% homology. In Drosophila, Btk29A displays a dynamic pattern of expression through the embryonic to adult stages. Complete loss-of-function of both splice-forms is lethal, whereas selective absence of the type 2-form reduces the adult lifespan of the fly and causes developmental abnormalities in male genitalia. METHODOLOGY/PRINCIPAL FINDINGS: Out of 7004-7979 transcripts expressed in the four sample groups, 5587 (70-79% were found in all four tissues and strains. Here, we investigated the role of Btk29A type 2 on a transcriptomic level in larval CNS and adult heads. We used samples either selectively defective in Btk29A type 2 (Btk29A(ficP or revertant flies with restored Btk29A type 2-function (Btk29A(fic Exc1-16. The whole transcriptomic profile for the different sample groups revealed Gene Ontology patterns reflecting lifespan abnormalities in adult head neuronal tissue, but not in larvae. CONCLUSIONS: In the Btk29A type 2-deficient strains there was no significant overlap between transcriptomic alterations in adult heads and larvae neuronal tissue, respectively. Moreover, there was no significant overlap of the transcriptomic changes between flies and mammals, suggesting that the evolutionary conservation is confined

  7. Unbiased identification of substrates of protein tyrosine phosphatase ptp-3 in C. elegans.

    Science.gov (United States)

    Mitchell, Christopher J; Kim, Min-Sik; Zhong, Jun; Nirujogi, Raja Sekhar; Bose, Anjun K; Pandey, Akhilesh

    2016-06-01

    The leukocyte antigen related (LAR) family of receptor-like protein tyrosine phosphatases has three members in humans - PTPRF, PTPRD and PTPRS - that have been implicated in diverse processes including embryonic development, inhibition of cell growth and axonal guidance. Mutations in the LAR family are associated with developmental defects such as cleft palate as well as various cancers including breast, neck, lung, colon and brain. Although this family of tyrosine phosphatases is important for many developmental processes, little is known of their substrates. This is partially due to functional redundancy within the LAR family, as deletion of a single gene in the LAR family does not have an appreciable phenotype, but a dual knockout is embryonically lethal in mouse models. To circumvent the inability to knockout multiple members of the LAR family in mouse models, we used a knockout of ptp-3, which is the only known ortholog of the LAR family in Caenorhabditis elegans and allows for the study of the LAR family at the organismal level. Using SILAC-based quantitative phosphoproteomics, we identified 255 putative substrates of ptp-3, which included four of the nine known annotated substrates of the LAR family. A motif analysis of the identified phosphopeptides allowed for the determination of sequences that appear to be preferentially dephosphorylated. Finally, we discovered that kinases were overrepresented in the list of identified putative substrates and tyrosine residues whose phosphorylation is known to increase kinase activity were dephosphorylated by ptp-3. These data are suggestive of ptp-3 as a potential negative regulator of several kinase families, such as the mitogen activated kinases (MAPKs), and multiple tyrosine kinases including FER, MET, and NTRK2. PMID:27067626

  8. Determination of o-tyrosine in irradiated chicken

    International Nuclear Information System (INIS)

    The author explains his method to determine O-Tyrosine in irradiated chickens with a high-performance liquid chromatography. The method is simple and fast, but a proper chromatographic separation is difficult. The detection limit with a high sensitive detector is about 0.05-0.1 mg O-Tyrosine/kg meat (9 refs)

  9. Analysis of corkscrew signaling in the Drosophila epidermal growth factor receptor pathway during myogenesis.

    OpenAIRE

    Johnson Hamlet, M R; Perkins, L A

    2001-01-01

    The Drosophila nonreceptor protein tyrosine phosphatase, Corkscrew (Csw), functions positively in multiple receptor tyrosine kinase (RTK) pathways, including signaling by the epidermal growth factor receptor (EGFR). Detailed phenotypic analyses of csw mutations have revealed that Csw activity is required in many of the same developmental processes that require EGFR function. However, it is still unclear where in the signaling hierarchy Csw functions relative to other proteins whose activities...

  10. Measurement of optical purity of p-BPA-Tyrosine dipeptide

    Energy Technology Data Exchange (ETDEWEB)

    Yoshino, K.; Sato, N.; Kitta, K.; Saitake, Y. [Shinshu Univ., Faculty of Science, Matsumoto, Nagano (Japan); Hiratsuka, J. [Kawasaki Medical School, Dept. of Radiation Oncology, Kurashiki, Okayama (Japan); Ichihashi, M. [Kobe Univ. (Japan). School of Medicine

    2000-10-01

    Melanin biosynthesis is very active in melanoma cells, and tyrosine is one of the substrates of the melanin biosynthesis. Tyrosine is oxidized to dopa by tyrosinase at the beginning of melanin biosynthesis process. Therefore, p-boronophenylalanine (BPA)-tyrosine dipeptide is expected to be a substrate of melanin biosynthesis process, and the peptide will be incorporated in melanoma cells, and then tumor boron concentration lasts in their cells for long time. Since p-BPA tyrosine are amino acids, they have D, L isomers. Therefore, we have tried to synthesize four isomers (L-L, L-D, D-L, D-D) of p-BPA-Tyrosine dipeptide, and have measured their optical purity with HPLC. (author)

  11. Measurement of optical purity of p-BPA-Tyrosine dipeptide

    International Nuclear Information System (INIS)

    Melanin biosynthesis is very active in melanoma cells, and tyrosine is one of the substrates of the melanin biosynthesis. Tyrosine is oxidized to dopa by tyrosinase at the beginning of melanin biosynthesis process. Therefore, p-boronophenylalanine (BPA)-tyrosine dipeptide is expected to be a substrate of melanin biosynthesis process, and the peptide will be incorporated in melanoma cells, and then tumor boron concentration lasts in their cells for long time. Since p-BPA tyrosine are amino acids, they have D, L isomers. Therefore, we have tried to synthesize four isomers (L-L, L-D, D-L, D-D) of p-BPA-Tyrosine dipeptide, and have measured their optical purity with HPLC. (author)

  12. Kinase-Catalyzed Biotinylation

    OpenAIRE

    Senevirathne, Chamara; Green, Keith D.; Pflum, Mary Kay H.

    2012-01-01

    Kinase-catalyzed protein phosphorylation plays an essential role in a variety of biological processes. Methods to detect phosphoproteins and phosphopeptides in cellular mixtures will aid in cell biological and signaling research. Our laboratory recently discovered the utility of γ-modified ATP analogues as tools for studying phosphorylation. Specifically, ATP-biotin can be used for labeling and visualizing phosphoproteins from cell lysates. Because the biotin tag is suitable for protein detec...

  13. Simple screening method for autoantigen proteins using the N-terminal biotinylated protein library produced by wheat cell-free synthesis.

    Science.gov (United States)

    Matsuoka, Kazuhiro; Komori, Hiroaki; Nose, Masato; Endo, Yaeta; Sawasaki, Tatsuya

    2010-08-01

    Autoimmune diseases are a heterogeneous group of diseases characterized by immune reactions against either a major or a limited number of the bodies own autoantigens, causing inflammation and damage to tissues and organs. Thus, identification of autoantigens is an important first step to understanding autoimmune diseases. Here we demonstrate a simple screening method for identification of autoantigens reacting with patient serum antibodies by combination of an N-terminal biotinylated protein library (BPL), produced using a wheat cell-free protein production system, and a commercially available luminescence system. Optimization studies using well-characterized autoantigens showed specific interactions between N-terminal biotinylated proteins and antibody that were sensitively detected under homogeneous reaction conditions. In this optimized assay, 1 microL of the translation mixture expressing the biotinylated proteins produced significant luminescence signal by addition of diluted serum between 1:500 and 1:10 000 in 25 microL of reaction volume. For the BPL construction, 214 mouse genes, consisting of 103 well-known autoantigens and 111 genes in the mouse autoimmune susceptibility loci, and the sera of MRL/lpr mouse were used as an autoimmune model. By this screening method, 25 well-known autoantigens and 71 proteins in the loci were identified as autoantigen proteins specifically reacting with sera antibodies. Cross-referencing with the Gene Ontology Database, 26 and 38 of autoantigen proteins were predicted to have nuclear localization and identified as membrane and/or extracellular proteins. The immune reaction of six randomly selected proteins was confirmed by immunoprecipitation and/or immunoblot analyses. Interestingly, three autoantigen proteins were recognized by immunoprecipitation but not by immunoblot analysis. These results suggest that the BPL-based method could provide a simple system for screening of autoantigen proteins and would help with

  14. Spectroscopic studies of fluorescent complexes of tyrosine 8-hydroxyquinoline and tyrosine-8-hydroxyquinaldine in aqueous phase

    International Nuclear Information System (INIS)

    A new method has been developed by preparing complexes involving condensation of tyrosine with 8-hydroxyquinoline (Oxine) and 8-hydroxyquinaldine (Quinaldine) respectively, producing fluorescent products. The products obtained have been investigated for identification and quantitative estimation using different spectroscopic techniques including fluorescence activity of newly synthesized products. 8-hydroxyquinaldine and 8-hydroxyquinoline (Oxine) condensed with tyrosine separately produced water soluble fluorescent complexes. The complexes have been investigated for identification and quantitative estimation of amino acids. Identification of amino acids in nano mole or below than nano mole has become possible by present fluorometric activity of these complexes involving different excitation and emission wavelengths. The fluorometric activity of complexes has been observed to be 100 to 1000 times higher than assay method involving ninhydrin and amino acid analyzer. The method adopted in our laboratory is rapid, versatile with good reproducibility and provides excellent results for adoption by analytical, agricultural and biomedical laboratories to estimate amino acids and metals in composite matrix. (author)

  15. Food for creativity: tyrosine promotes deep thinking.

    Science.gov (United States)

    Colzato, Lorenza S; de Haan, Annelies M; Hommel, Bernhard

    2015-09-01

    Anecdotal evidence suggests that creative people sometimes use food to overcome mental blocks and lack of inspiration, but empirical support for this possibility is still lacking. In this study, we investigated whether creativity in convergent- and divergent-thinking tasks is promoted by the food supplement L-Tyrosine (TYR)-a biochemical precursor of dopamine, which is assumed to drive cognitive control and creativity. We found no evidence for an impact of TYR on divergent thinking ("brainstorming") but it did promote convergent ("deep") thinking. As convergent thinking arguably requires more cognitive top-down control, this finding suggests that TYR can facilitate control-hungry creative operations. Hence, the food we eat may affect the way we think. PMID:25257259

  16. Protein tyrosine phosphatase PTPN14 is a regulator of lymphatic function and choanal development in humans.

    Science.gov (United States)

    Au, Audrey C; Hernandez, Paolo A; Lieber, Ernest; Nadroo, Ali M; Shen, Yu-Ming; Kelley, Kevin A; Gelb, Bruce D; Diaz, George A

    2010-09-10

    The lymphatic vasculature is essential for the recirculation of extracellular fluid, fat absorption, and immune function and as a route of tumor metastasis. The dissection of molecular mechanisms underlying lymphangiogenesis has been accelerated by the identification of tissue-specific lymphatic endothelial markers and the study of congenital lymphedema syndromes. We report the results of genetic analyses of a kindred inheriting a unique autosomal-recessive lymphedema-choanal atresia syndrome. These studies establish linkage of the trait to chromosome 1q32-q41 and identify a loss-of-function mutation in PTPN14, which encodes a nonreceptor tyrosine phosphatase. The causal role of PTPN14 deficiency was confirmed by the generation of a murine Ptpn14 gene trap model that manifested lymphatic hyperplasia with lymphedema. Biochemical studies revealed a potential interaction between PTPN14 and the vascular endothelial growth factor receptor 3 (VEGFR3), a receptor tyrosine kinase essential for lymphangiogenesis. These results suggest a unique and conserved role for PTPN14 in the regulation of lymphatic development in mammals and a nonconserved role in choanal development in humans. PMID:20826270

  17. Tyrosine depletion lowers in vivo DOPA synthesis in ventral hippocampus.

    Science.gov (United States)

    Bongiovanni, Rodolfo; Kyser, Abby N; Jaskiw, George E

    2012-12-01

    In vivo dopamine synthesis in the medial prefrontal cortex of the rat is sensitive to the availability of tyrosine. Whether other limbic cortical dopamine terminal regions are similarly tyrosine-dependent is not known. In this study we examined the effects of tyrosine depletion on dopamine synthesis and catecholamine levels in the ventral hippocampus. A tyrosine- and phenylalanine-free neutral amino acid mixture was used to lower brain tyrosine levels in rats undergoing in vivo microdialysis. In one group, NSD-1015 was included in perfusate to permit measurement of DOPA levels. In a second group, NSD-1015 was not included in perfusate so that catecholamine levels could be assayed. Tyrosine depletion significantly lowered DOPA levels in the NSD-1015 treated group and lowered DOPAC but not dopamine or noradrenaline levels in the group not exposed to NSD-1015. We conclude that while catecholamine synthesis in the ventral hippocampus declines when tyrosine availability is lowered, under basal conditions, compensatory mechanisms are able to maintain stable extracellular catecholamine levels. PMID:23022716

  18. pH regulation of an egg cortex tyrosine kinase.

    Science.gov (United States)

    Jiang, W P; Veno, P A; Wood, R W; Peaucellier, G; Kinsey, W H

    1991-07-01

    Fertilization of the echinoderm egg is known to result in the phosphorylation, on tyrosine, of a high-molecular-weight cortical protein (HMWCP) localized in the egg cortex. Studies using various parthenogenic agents indicate that this phosphorylation event occurs in response to the alkaline shift in cytoplasmic pHi which normally occurs 1 to 2 min after fertilization. In the present study, the purified egg cell surface complex was used as in vitro system to determine whether a small alkaline shift in pH, such as occurs upon fertilization, could stimulate the activity of the egg cortex-associated tyrosine kinase toward endogenous protein substrates. The results demonstrated that the cell surface complex is highly enriched in a tyrosine kinase activity which accounts for the majority of the protein kinase activity in this preparation. The activity of this tyrosine kinase toward the HMWCP and other cortical proteins was highly dependent on pH over the range pH 6.8 to 7.3. This indicates that the fertilization-associated change in cytoplasmic pH would be sufficient to trigger increased tyrosine phosphorylation of the high-molecular-weight cortical protein in vivo. The regulation of tyrosine phosphorylation by small changes in pH represents a novel control mechanism in which a tyrosine protein kinase may act as a pH-sensitive transducer. PMID:2060713

  19. Afatinib: emerging next-generation tyrosine kinase inhibitor for NSCLC

    Directory of Open Access Journals (Sweden)

    Nelson V

    2013-03-01

    Full Text Available Valerie Nelson, Jacqueline Ziehr, Mark Agulnik, Melissa JohnsonRobert H Lurie Comprehensive Cancer Center of Northwestern University, Chicago, IL, USAAbstract: The discovery of epidermal growth-factor receptor (EGFR-activating mutations and the introduction of oral EGFR tyrosine kinase inhibitors (EGFR-TKIs have expanded the treatment options for patients with non-small cell lung cancer. The first two reversible EGFR-TKIs, erlotinib and gefitinib, are approved for use in the first-line setting in patients with known EGFR-activating mutations and in the second- and third-line settings for all NSCLC patients. These first-generation EGFR-TKIs improve progression-free survival when compared to chemotherapy in patients with EGFR-activating mutations in the first-line setting. However, nearly all patients develop resistance to EGFR-directed agents. There is a need for further therapy options for patients with disease progression after treatment with reversible EGFR-TKIs. Afatinib is an irreversible ErbB family blocker that inhibits EGFR, HER2, and HER4. In vitro and in vivo, afatinib have shown increased inhibition of the common EGFR-activating mutations as well as the T790M resistance mutation when compared to erlotinib and gefitinib. Clinically, afatinib has been evaluated in the LUX-Lung series of trials, with improvement in progression-free survival reported in patients with EGFR-activating mutations in both first- and second-/third-line settings when compared to chemotherapy. Further investigation is needed to determine the precise role that afatinib will play in the treatment of patients with non-small cell lung cancer and EGFR-activating mutations.Keywords: afatinib, EGFR, irreversible EGFR inhibitor, EGPR-TKIs, LUX lung, resistance mutation, targeted therapy

  20. Understanding proton affinity of tyrosine sidechain in hydrophobic confinement

    Indian Academy of Sciences (India)

    T G Abi; T Karmakar; S Taraphder

    2012-01-01

    Tyrosine is an important amino acid residue that plays a key role in several biochemical transformations such as, abstraction/donation of proton from/by its sidechain. We present here a density functional study on the proton affinity of tyrosine sidechain suspended inside the core of a single walled carbon nanotube that mimics the environment of protein structural pores and molecular channels. Tyrosine is found to exhibit a lower reactivity on confinement and unlike several other polar amino acid sidechains, its reactivity does not respond to hydrogen bonding with neighbouring hydroxyl groups.

  1. Modulation of A2a receptor antagonist on D2 receptor internalization and ERK phosphorylation

    OpenAIRE

    Huang, Li; Wu, Dong-Dong; Zhang, Lei; Feng, Lin-yin

    2013-01-01

    Aim: To explore the effects of heterodimerization of D2 receptor/A2a receptor (D2R/A2aR) on D2R internalization and D2R downstream signaling in primary cultured striatal neurons and HEK293 cells co-expressing A2aR and D2R in vitro. Methods: Primary cultured rat striatal neurons and HEK293 cells co-expressing A2aR and D2R were treated with A2aR- or D2R-specific agonists. D2R internalization was detected using a biotinylation assay and confocal microscopy. ERK, Src kinase and β-arrestin were me...

  2. Damnacanthal inhibits the NF-κB/RIP-2/caspase-1 signal pathway by inhibiting p56lck tyrosine kinase.

    Science.gov (United States)

    Kim, Min-Ho; Jeong, Hyun-Ja

    2014-10-01

    Damnacanthal is a major constituent of Morinda citrifolia L. (noni) and exhibits anti-cancer and anti-inflammatory activities. However, the effects of damnacanthal on allergic diseases have not been determined. In this study, we investigated the effect of damnacanthal on mast cell-mediated allergic inflammatory responses. Damnacanthal significantly and dose-dependently inhibited compound 48/80-induced systemic anaphylactic shock, histamine release and intracellular calcium levels. In particular, IgE-mediated passive cutaneous anaphylaxis was significantly inhibited by the oral administration of damnacanthal. In addition, we report for the first time that p56lck tyrosine kinase was expressed in phorbol 12-myristate 13-acetate and calcium ionophore A23187 (PMACI)-stimulated mast cells. Furthermore, damnacanthal inhibited the up-regulation of p56lck tyrosine kinase activity by PMACI and repressed PMACI-induced histidine decarboxylase expression and activity. Damnacanthal also inhibited PMACI-induced interleukin (IL)-1β, IL-6 and tumor necrosis factor-α expressions by suppressing nuclear factor-kappa B (NF-κB) activation and suppressed the activation of caspase-1 and the expression of receptor interacting protein-2. This study shows damnacanthal inhibits the NF-κB/receptor-interacting protein-2/caspase-1 signal pathway by inhibiting p56lck tyrosine kinase and suggests that damnacanthal has potential for the treatment of mast cell-mediated allergic disorders. PMID:25139491

  3. Tyrosine kinase signalling in breast cancer: Modulation of tyrosine kinase signalling in human breast cancer through altered expression of signalling intermediates

    International Nuclear Information System (INIS)

    The past decade has seen the definition of key signalling pathways downstream of receptor tyrosine kinases (RTKs) in terms of their components and the protein-protein interactions that facilitate signal transduction. Given the strong evidence that links signalling by certain families of RTKs to the progression of breast cancer, it is not surprising that the expression profile of key downstream signalling intermediates in this disease has also come under scrutiny, particularly because some exhibit transforming potential or amplify mitogenic signalling pathways when they are overexpressed. Reflecting the diverse cellular processes regulated by RTKs, it is now clear that altered expression of such signalling proteins in breast cancer may influence not only cellular proliferation (eg Grb2) but also the invasive properties of the cancer cells (eg EMS1/cortactin)

  4. Prolactin receptor and signal transduction to milk protein genes

    Energy Technology Data Exchange (ETDEWEB)

    Djiane, J.; Daniel, N.; Bignon, C. [Unite d`Endocrinologie Moleculaire, Jouy en Josas (France)] [and others

    1994-06-01

    After cloning of the mammary gland prolactin (PRL) receptor cDNA, a functional assay was established using co-transfection of PRL receptor cDNA together with a milk protein promoter/chloramphenicol acetyl transferase (CAT) construct in Chinese hamster ovary (CHO) cells. Different mutants of the PRL receptor were tested in this CAT assay to delimit the domains in the receptor necessary for signal transduction to milk protein genes. In CHO cells stably transfected with PRL receptor cDNA, high numbers of PRL receptor are expressed. By metabolic labeling and immunoprecipitation, expressed PRL receptor was identified as a single species of 100 kDa. Using these cells, we analyzed the effects of PRL on intracellular free Ca{sup ++} concentration. PRL stimulates Ca{sup ++} entry and induces secondary Ca{sup ++} mobilization. The entry of Ca{sup ++} is a result of an increase in K{sup +} conductance that hyperpolarizes the membranes. We have also analyzed tyrosine phosphorylation induced by PRL. In CHO cells stably transfected with PRL receptor cDNA, PRL induced a very rapid and transient tyrosine phosphorylation of a 100-kDa protein which is most probably the PRL receptor. The same finding was obtained in mammary membranes after PRL injection to lactating rabbits. Whereas tyrosine kinase inhibitors genistein and lavendustin were without effect, PRL stimulation of milk protein gene promoters was partially inhibited by 2 {mu}M herbimycin in CHO cells co-transfected with PRL receptor cDNA and the {Beta} lactoglobulin CAT construct. Taken together these observations indicate that the cytoplasmic domain of the PRL receptor interacts with one or several tyrosine kinases, which may represent early postreceptor events necessary for PRL signal transduction to milk protein genes. 14 refs., 4 figs.

  5. Cytochrome c Is Tyrosine 97 Phosphorylated by Neuroprotective Insulin Treatment

    Czech Academy of Sciences Publication Activity Database

    Sanderson, T. H.; Mahapatra, G.; Pecina, Petr; Ji, Q.; Yu, K.; Sinkler, Ch.; Varughese, A.; Kumar, R.; Bukowski, M. J.; Tousignant, R. N.; Salomon, A. R.; Lee, I.; Hüttemann, M.

    2013-01-01

    Roč. 8, č. 11 (2013), e78627. E-ISSN 1932-6203 Institutional support: RVO:67985823 Keywords : cytochrome c * tyrosine phosphorylation * brain ischemia * insulin Subject RIV: ED - Physiology Impact factor: 3.534, year: 2013

  6. Complete remission with tyrosine kinase inhibitors in renal cell carcinoma

    OpenAIRE

    Albiges, Laurence; Oudard, Stéphane; Negrier, Sylvie; Caty, Armelle; Gravis, Gwenaëlle; Joly, Florence; Duclos, Brigitte; Geoffrois, Lionel; Rolland, Frédéric; Guillot, Aline; Laguerre, Brigitte; Legouffe, Eric; Kohser, Frédéric; Dietrich, Pierre-Yves; Theodore, Christine A

    2012-01-01

    Complete remission (CR) is uncommon during treatment for metastatic renal cell carcinoma (mRCC) with tyrosine kinase inhibitors (TKIs), but it may occur in some patients. It remains a matter of debate whether therapy should be continued after CR.

  7. Direct observation of spin-injection in tyrosinate-functionalized single-wall carbon nanotubes

    NARCIS (Netherlands)

    Tsoufis, Theodoros; Ampoumogli, Asem; Gournis, Dimitrios; Georgakilas, Vasilios; Jankovic, Lubos; Christoforidis, Konstantinos C.; Deligiannakis, Yiannis; Mavrandonakis, Andreas; Froudakis, George E.; Maccallini, Enrico; Rudolf, Petra; Mateo-Alonso, Aurelio; Prato, Maurizio

    2014-01-01

    In this work, we report on the interaction of a tyrosinate radical with single wall carbon nanotubes (CNT). The tyrosinate radical was formed from tyrosine (ester) by Fenton's reagent and, reacted in situ with carbon nanotubes resulting in novel tyrosinated carbon nanotube derivatives. The covalent

  8. Evaluation of Enrichment Techniques for Mass Spectrometry : Identification of Tyrosine Phosphoproteins in Cancer Cells

    OpenAIRE

    Schumacher, Jonathan A.; Crockett, David K.; Elenitoba-Johnson, Kojo S.J.; Lim, Megan S.

    2007-01-01

    Phosphorylation of tyrosine residues by protein tyrosine kinases mediates numerous cellular processes. Deregulated tyrosine phosphorylation underlies constitutive activation of signaling pathways leading to oncogenesis. Analytical techniques for evaluation of the global phosphoproteome level are challenging and can be improved on to enhance yields. Here, we evaluated several approaches to enrich for tyrosine phosphoproteins in cancer cells for subsequent liquid chromatography-tandem mass spec...

  9. Tyrosine Phosphatase Inhibition Induces an ASC-dependent Pyroptosis

    OpenAIRE

    Ghonime, Mohammed G.; Shamaa, Obada R.; Eldomany, Ramadan A.; Gavrilin, Mikhail A.; Wewers, Mark D.

    2012-01-01

    Pyroptosis is a type of cell death in which danger associated molecular patterns (DAMPs) and pathogen associated molecular patterns (PAMPs) induce mononuclear phagocytes to activate caspase-1 and release mature IL-1β. Because the tyrosine kinase inhibitor AG126 can prevent DAMP/PAMP induced activation of caspase-1, we hypothesized that tipping the tyrosine kinase/phosphatase balance toward phosphorylation would promote caspase-1 activation and cell death. THP-1 derived macrophages were theref...

  10. Role of lymphocyte-specific protein tyrosine kinase (LCK) in the expansion of glioma-initiating cells by fractionated radiation

    International Nuclear Information System (INIS)

    Research highlights: → Activation of Lymphocyte-specific protein tyrosine kinase (LCK) is involved in the fractionated radiation-induced expansion of glioma stem-like cells. → Inhibition of LCK prevents acquisition of fractionated radiation-induced resistance to chemotherapeutic treatment. → LCK activity is critical for the maintenance of self-renewal in glioma stem-like cells. -- Abstract: Brain cancers frequently recur or progress as focal masses after treatment with ionizing radiation. Radiation used to target gliomas may expand the cancer stem cell population and enhance the aggressiveness of tumors; however, the mechanisms underlying the expansion of cancer stem cell population after radiation have remained unclear. In this study, we show that LCK (lymphocyte-specific protein tyrosine kinase) is involved in the fractionated radiation-induced expansion of the glioma-initiating cell population and acquisition of resistance to anticancer treatments. Fractionated radiation caused a selective increase in the activity of LCK, a Src family non-receptor tyrosine kinase. The activities of other Src family kinases Src, Fyn, and Lyn were not significantly increased. Moreover, knockdown of LCK expression with a specific small interfering RNA (siRNA) effectively blocked fractionated radiation-induced expansion of the CD133+ cell population. siRNA targeting of LCK also suppressed fractionated radiation-induced expression of the glioma stem cell marker proteins CD133, Nestin, and Musashi. Expression of the known self-renewal-related proteins Notch2 and Sox2 in glioma cells treated with fractionated radiation was also downregulated by LCK inhibition. Moreover, siRNA-mediated knockdown of LCK effectively restored the sensitivity of glioma cells to cisplatin and etoposide. These results indicate that the non-receptor tyrosine kinase LCK is critically involved in fractionated radiation-induced expansion of the glioma-initiating cell population and decreased cellular

  11. A novel role of protein tyrosine kinase2 in mediating chloride secretion in human airway epithelial cells.

    Directory of Open Access Journals (Sweden)

    Lihua Liang

    Full Text Available Ca(2+ activated Cl(- channels (CaCC are up-regulated in cystic fibrosis (CF airway surface epithelia. The presence and functional properties of CaCC make it a possible therapeutic target to compensate for the deficiency of Cl(- secretion in CF epithelia. CaCC is activated by an increase in cytosolic Ca(2+, which not only activates epithelial CaCCs, but also inhibits epithelial Na(+ hyperabsorption, which may also be beneficial in CF. Our previous study has shown that spiperone, a known antipsychotic drug, activates CaCCs and stimulates Cl(- secretion in polarized human non-CF and CF airway epithelial cell monolayers in vitro, and in Cystic Fibrosis Transmembrane Conductance Regulator (CFTR knockout mice in vivo. Spiperone activates CaCC not by acting in its well-known role as an antagonist of either 5-HT2 or D2 receptors, but through a protein tyrosine kinase-coupled phospholipase C-dependent pathway. Moreover, spiperone independently activates CFTR through a novel mechanism. Herein, we performed a mass spectrometry analysis and identified the signaling molecule that mediates the spiperone effect in activating chloride secretion through CaCC and CFTR. Proline-rich tyrosine kinase 2 (PYK2 is a non-receptor protein tyrosine kinase, which belongs to the focal adhesion kinase family. The inhibition of PYK2 notably reduced the ability of spiperone to increase intracellular Ca(2+ and Cl(- secretion. In conclusion, we have identified the tyrosine kinase, PYK2, as the modulator, which plays a crucial role in the activation of CaCC and CFTR by spiperone. The identification of this novel role of PYK2 reveals a new signaling pathway in human airway epithelial cells.

  12. Increased angiotensin II AT(1) receptor expression in paraventricular nucleus and hypothalamic-pituitary-adrenal axis stimulation in AT(2) receptor gene disrupted mice.

    Science.gov (United States)

    Armando, Inés; Terrón, José A; Falcón-Neri, Alicia; Takeshi, Ito; Häuser, Walter; Inagami, Tadashi; Saavedra, Juan M

    2002-09-01

    Angiotensin II AT(2) receptor gene-disrupted mice have increased blood pressure and response to angiotensin II, behavioral alterations, greater response to stress, and increased adrenal AT(1) receptors. We studied hypothalamic AT(1) receptor binding and mRNA by receptor autoradiography and in situ hybridization, adrenal catecholamines by HPLC, adrenal tyrosine hydroxylase mRNA by in situ hybridization and pituitary and adrenal hormones by RIA in AT(2) receptor-gene disrupted mice and wild-type controls. To confirm the role of adrenal AT(1) receptors, we treated wild-type C57 BL/6J mice with the AT(1) antagonist candesartan for 2 weeks, and measured adrenal hormones, catecholamines and tyrosine hydroxylase mRNA. In the absence of AT(2) receptor transcription, we found increased AT(1) receptor binding in brain areas involved in the regulation of the hypothalamic-pituitary-adrenal axis, the hypothalamic paraventricular nucleus and the median eminence, and increased adrenal catecholamine synthesis as shown by higher adrenomedullary tyrosine hydroxylase mRNA and higher adrenal dopamine, norepinephrine and epinephrine levels when compared to wild-type mice. In addition, in AT(2) receptor gene-disrupted mice there were higher plasma adrenocorticotropin (ACTH) and corticosterone levels and lower adrenal aldosterone content when compared to wild-type controls. Conversely, AT(1) receptor inhibition in CB57 BL/6J mice reduced adrenal tyrosine hydroxylase mRNA and catecholamine content and increased adrenal aldosterone content. These results can help to explain the enhanced response of AT(2) receptor gene-disrupted mice to exogenous angiotensin II, support the hypothesis of cross-talk between AT(1) and AT(2) receptors, indicate that the activity of the hypothalamic-pituitary-adrenal axis parallels the AT(1) receptor expression, and suggest that expression of AT(1) receptors can be dependent on AT(2) receptor expression. Our results provide an explanation for the increased

  13. A vital role of tubulin-tyrosine-ligase for neuronal organization

    OpenAIRE

    Erck, Christian; Peris, Leticia; Andrieux, Annie; Meissirel, Claire; Gruber, Achim; Vernet, Muriel; Schweitzer, Annie; Saoudi, Yasmina; Pointu, Hervé; Bosc, Christophe; Salin, Paul; Job, Didier; Wehland, Juergen

    2005-01-01

    http://www.pnas.org/content/102/22/7853.long International audience Tubulin is subject to a special cycle of detyrosination/tyrosination in which the C-terminal tyrosine of alpha-tubulin is cyclically removed by a carboxypeptidase and readded by a tubulin-tyrosine-ligase (TTL). This tyrosination cycle is conserved in evolution, yet its physiological importance is unknown. Here, we find that TTL suppression in mice causes perinatal death. A minor pool of tyrosinated (Tyr-)tubulin persist...

  14. Tyrosine sulfation of the amino terminus of PSGL-1 is critical for enterovirus 71 infection.

    Directory of Open Access Journals (Sweden)

    Yorihiro Nishimura

    Full Text Available Enterovirus 71 (EV71 is one of the major causative agents of hand, foot, and mouth disease, a common febrile disease in children; however, EV71 has been also associated with various neurological diseases including fatal cases in large EV71 outbreaks particularly in the Asia Pacific region. Recently we identified human P-selectin glycoprotein ligand-1 (PSGL-1 as a cellular receptor for entry and replication of EV71 in leukocytes. PSGL-1 is a sialomucin expressed on the surface of leukocytes, serves as a high affinity counterreceptor for selectins, and mediates leukocyte rolling on the endothelium. The PSGL-1-P-selectin interaction requires sulfation of at least one of three clustered tyrosines and an adjacent O-glycan expressing sialyl Lewis x in an N-terminal region of PSGL-1. To elucidate the molecular basis of the PSGL-1-EV71 interaction, we generated a series of PSGL-1 mutants and identified the post-translational modifications that are critical for binding of PSGL-1 to EV71. We expressed the PSGL-1 mutants in 293T cells and the transfected cells were assayed for their abilities to bind to EV71 by flow cytometry. We found that O-glycosylation on T57, which is critical for PSGL-1-selectin interaction, is not necessary for PSGL-1 binding to EV71. On the other hand, site-directed mutagenesis at one or more potential tyrosine sulfation sites in the N-terminal region of PSGL-1 significantly impaired PSGL-1 binding to EV71. Furthermore, an inhibitor of sulfation, sodium chlorate, blocked the PSGL-1-EV71 interaction and inhibited PSGL-1-mediated viral replication of EV71 in Jurkat T cells in a dose-dependent manner. Thus, the results presented in this study reveal that tyrosine sulfation, but not O-glycosylation, in the N-terminal region of PSGL-1 may facilitate virus entry and replication of EV71 in leukocytes.

  15. Epidermal growth factor receptor signalling in human breast cancer cells operates parallel to estrogen receptor α signalling and results in tamoxifen insensitive proliferation.

    NARCIS (Netherlands)

    Moerkens, M.; Zhang, Y.; Wester, L.; Water, van de B.; Meerman, J.H.N.

    2014-01-01

    BACKGROUND Tamoxifen resistance is a major problem in the treatment of estrogen receptor (ER) α -positive breast cancer patients. Although the mechanisms behind tamoxifen resistance are still not completely understood, clinical data suggests that increased expression of receptor tyrosine kinases is

  16. Implications of tyrosine phosphoproteomics in cervical carcinogenesis

    Directory of Open Access Journals (Sweden)

    DeFord James

    2008-01-01

    Full Text Available Abstract Background Worldwide cervical cancer remains a leading cause of mortality from gynecologic malignancies. The link between cervical cancer and persistent infection with HPV has been established. At a molecular level little is known about the transition from the precancerous state to invasive cancer. To elucidate this process, cervical biopsies from human specimens were obtained from precancerous state to stage III disease. Methods Cervical biopsies were obtained from patients with a diagnosis of cervical cancer undergoing definitive surgery or staging operation. Biopsies were obtained from patients with precancerous lesions at the time of their excisional procedure. Control samples were obtained from patients undergoing hysterectomy for benign conditions such as fibroids. Samples were subjected to proteomic profiling using two dimensional gel electrophoresis with subsequent trypsin digestion followed by MALDI-TOF protein identification. Candidate proteins were then further studied using western blotting, immunoprecipitation and immunohistochemistry. Results Annexin A1 and DNA-PKcs were found to be differentially expressed. Phosphorylated annexin A1 was up regulated in diseased states in comparison to control and its level was strongly detected in the serum of cervical cancer patients compared to controls. DNA-PKcs was noted to be hyperphosphorylated and fragmented in cancer when compared to controls. By immunohistochemistry annexin A1 was noted in the vascular environment in cancer and certain precancerous samples. Conclusion This study suggests a probable role for protein tyrosine phosphorylation in cervical carcinogenesis. Annexin A1 and DNA-PK cs may have synergistic effects with HPV infection. Precancerous lesions that may progress to cervical cancer may be differentiated from lesions that will not base on similar immunohistochemical profile to invasive squamous cell carcinoma.

  17. Co-conserved features associated with cis regulation of ErbB tyrosine kinases.

    Directory of Open Access Journals (Sweden)

    Amar Mirza

    Full Text Available BACKGROUND: The epidermal growth factor receptor kinases, or ErbB kinases, belong to a large sub-group of receptor tyrosine kinases (RTKs, which share a conserved catalytic core. The catalytic core of ErbB kinases have functionally diverged from other RTKs in that they are activated by a unique allosteric mechanism that involves specific interactions between the kinase core and the flanking Juxtamembrane (JM and COOH-terminal tail (C-terminal tail. Although extensive studies on ErbB and related tyrosine kinases have provided important insights into the structural basis for ErbB kinase functional divergence, the sequence features that contribute to the unique regulation of ErbB kinases have not been systematically explored. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we use a Bayesian approach to identify the selective sequence constraints that most distinguish ErbB kinases from other receptor tyrosine kinases. We find that strong ErbB kinase-specific constraints are imposed on residues that tether the JM and C-terminal tail to key functional regions of the kinase core. A conserved RIxKExE motif in the JM-kinase linker region and a glutamine in the inter-lobe linker are identified as two of the most distinguishing features of the ErbB family. While the RIxKExE motif tethers the C-terminal tail to the N-lobe of the kinase domain, the glutamine tethers the C-terminal tail to hinge regions critical for inter-lobe movement. Comparison of the active and inactive crystal structures of ErbB kinases indicates that the identified residues are conformationally malleable and can potentially contribute to the cis regulation of the kinase core by the JM and C-terminal tail. ErbB3, and EGFR orthologs in sponges and parasitic worms, diverge from some of the canonical ErbB features, providing insights into sub-family and lineage-specific functional specialization. CONCLUSION/SIGNIFICANCE: Our analysis pinpoints key residues for mutational analysis, and

  18. TAM receptors affect adult brain neurogenesis by negative regulation of microglial cell activation1

    OpenAIRE

    Ji, Rui; Tian, Shifu; Lu, Helen J.; LU, QINGJUN; Yan ZHENG; Wang, Xiaomin; Ding, Jixiang; Li, Qiutang; Lu, Qingxian

    2013-01-01

    TAM tyrosine kinases play multiple functional roles including regulation of the target genes important in homeostatic regulation of cytokine receptors or Toll-like receptor-mediated signal transduction pathways. Here, we show that TAM receptors affect adult hippocampal neurogenesis and loss of TAM receptors impair hippocampal neurogenesis, largely attributed to exaggerated inflammatory responses by microglia characterized by increased MAP kinase and NF-κB activation and elevated production of...

  19. Expression of somatostatin receptor genes and acetylcholine receptor development in rat skeletal muscle during postnatal development.

    Science.gov (United States)

    Peng, M; Conforti, L; Millhorn, D E

    1998-05-01

    Our laboratory reported previously that somatostatin (SST) is transiently expressed in rat motoneurons during the first 14 days after birth. We investigated the possibility that the SST receptor (SSTR) is expressed in skeletal muscle. We found that two of the five subtypes of SSTR (SSTR3 and SSTR4) are expressed in skeletal muscle with a time course that correlates with the transient expression of SST in motoneurons. In addition, SSTR2A is expressed from birth to adulthood in skeletal muscle. Both SSTR2A and SSTR4 are also expressed in L6 cells, a skeletal muscle cell line. Somatostatin acting through its receptors has been shown to stimulate tyrosine phosphatase activity in a number of different tissues. We found that several proteins (50, 65, 90, 140, 180 and 200 kDa) exhibited a reduced degree of tyrosine phosphorylation following SST treatment. Inhibition of tyrosine phosphatase activity with sodium orthovanadate increased expression of the nicotinic acetyl-choline receptor (nAChR) epsilon subunit mRNA by three fold. Somatostatin reversed the elevated epsilon mRNA following orthovanadate treatment. These findings show that SSTR is expressed in skeletal muscle and that SST acting via the SSTR regulates tyrosine phosphorylation and expression of the epsilon subunit of the AChR in the rat skeletal muscle. PMID:9852305

  20. Synthesis of Biotin Linkers with the Activated Triple Bond Donor [p-(N-propynoylaminotoluic Acid] (PATA for Efficient Biotinylation of Peptides and Oligonucleotides

    Directory of Open Access Journals (Sweden)

    Martina Jezowska

    2012-11-01

    Full Text Available Biotin is an important molecule for modern biological studies including, e.g., cellular transport. Its exclusive affinity to fluorescent streptavidin/avidin proteins allows ready and specific detection. As a consequence methods for the attachment of biotin to various biological targets are of high importance, especially when they are very selective and can also proceed in water. One useful method is Hüisgen dipolar [3+2]-cycloaddition, commonly referred to as “click chemistry”. As we reported recently, the activated triple bond donor p-(N-propynoylaminotoluic acid (PATA gives excellent results when used for conjugations at submicromolar concentrations. Thus, we have designed and synthesized two biotin linkers, with different lengths equipped with this activated triple bond donor and we proceeded with biotinylation of oligonucleotides and C-myc peptide both in solution and on solid support with excellent yields of conversion.