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Sample records for abelson tyrosine kinase

  1. Efficacy of the polo-like kinase inhibitor rigosertib, alone or in combination with Abelson tyrosine kinase inhibitors, against break point cluster region-c-Abelson-positive leukemia cells.

    Science.gov (United States)

    Okabe, Seiichi; Tauchi, Tetsuzo; Tanaka, Yuko; Sakuta, Juri; Ohyashiki, Kazuma

    2015-08-21

    The potency of Abelson (ABL) tyrosine kinase inhibitors (TKIs) against chronic myeloid leukemia (CML) has been demonstrated. However, ABL TKI resistance can develop. In this study, we investigated the efficacy of a combination therapy including rigosertib (ON 01910.Na), a polo-like kinase (PLK) and phosphoinositide 3-kinase (PI3K) inhibitor, and ABL TKIs. A 72-h rigosertib treatment was found to inhibit cell growth, induce apoptosis, reduce phosphorylation of the breakpoint cluster region-c (BCR)-ABL and its substrate Crk-L, and increase the activities of caspase 3 and poly (ADP-ribose) polymerase (PARP). This combination therapy also exerted a synergistic inhibitory effect on Philadelphia chromosome (Ph)-positive cell proliferation and reduced the phosphorylation of BCR-ABL and Crk-L while increasing that of cleaved PARP and the H2A.X histone. Rigosertib also potently inhibited the growth of ABL TKI-resistant cells, and cotreatment with ABL TKIs and rigosertib induced higher cytotoxicity. These results indicate that rigosertib treatment may be a powerful strategy against ABL TKI-resistant cells and could enhance the cytotoxic effects of ABL TKIs.

  2. In the absence of frazzled over-expression of Abelson tyrosine kinase disrupts commissure formation and causes axons to leave the embryonic CNS.

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    Joy N Dorsten

    Full Text Available BACKGROUND: In the Drosophila embryonic nerve cord, the formation of commissures require both the chemoattractive Netrin receptor Frazzled (Fra and the Abelson (Abl cytoplasmic tyrosine kinase. Abl binds to the cytoplasmic domain of Fra and loss-of-function mutations in abl enhance fra-dependent commissural defects. To further test Abl's role in attractive signaling, we over-expressed Abl in Fra mutants anticipating rescue of commissures. METHODOLOGY/PRINCIPAL FINDINGS: The Gal4-UAS system was used to pan-neurally over-express Abl in homozygous fra embryos. Surprisingly, this led to a significant decrease in both posterior and anterior commissure formation and induced some commissural and longitudinal axons to project beyond the CNS/PNS border. Re-expressing wild-type Fra, or Fra mutants with a P-motif deleted, revert both commissural and exiting phenotypes, indicating that Fra is required but not a specific P-motif. This is supported by S2 cell experiments demonstrating that Abl binds to Fra independent of any specific P-motif and that Fra continues to be phosphorylated when individual P-motifs are removed. Decreasing midline repulsion by reducing Robo signaling had no effect on the Abl phenotype and the phenotypes still occur in a Netrin mutant. Pan-neural over-expression of activated Rac or Cdc42 in a fra mutant also induced a significant loss in commissures, but axons did not exit the CNS. CONCLUSION/SIGNIFICANCE: Taken together, these data suggest that Fra activity is required to correctly regulate Abl-dependent cytoskeletal dynamics underlying commissure formation. In the absence of Fra, increased Abl activity appears to be incorrectly utilized downstream of other guidance receptors resulting in a loss of commissures and the abnormal projections of some axons beyond the CNS/PNS border.

  3. Tyrosine Kinase Inhibitors and Diabetes: A Novel Treatment Paradigm?

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    Fountas, Athanasios; Diamantopoulos, Leonidas-Nikolaos; Tsatsoulis, Agathocles

    2015-11-01

    Deregulation of protein tyrosine kinase (PTK) activity is implicated in various proliferative conditions. Multi-target tyrosine kinase inhibitors (TKIs) are increasingly used for the treatment of different malignancies. Recently, several clinical cases of the reversal of both type 1 and 2 diabetes mellitus (T1DM, T2DM) during TKI administration have been reported. Experimental in vivo and in vitro studies have elucidated some of the mechanisms behind this effect. For example, inhibition of Abelson tyrosine kinase (c-Abl) results in β cell survival and enhanced insulin secretion, while platelet-derived growth factor receptor (PDGFR) and epidermal growth factor receptor (EGFR) inhibition leads to improvement in insulin sensitivity. In addition, inhibition of vascular endothelial growth factor receptor 2 (VEGFR2) reduces the degree of islet cell inflammation (insulitis). Therefore, targeting several PTKs may provide a novel approach for correcting the pathophysiologic disturbances of diabetes.

  4. Tyrosine kinases in rheumatoid arthritis

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    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.

  5. Bacterial Protein-Tyrosine Kinases

    DEFF Research Database (Denmark)

    Shi, Lei; Kobir, Ahasanul; Jers, Carsten

    2010-01-01

    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 tyrosine...

  6. 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

  7. Endocytosis of Receptor Tyrosine Kinases

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    Goh, Lai Kuan

    2013-01-01

    Endocytosis is the major regulator of signaling from receptor tyrosine kinases (RTKs). The canonical model of RTK endocytosis involves rapid internalization of an RTK activated by ligand binding at the cell surface and subsequent sorting of internalized ligand-RTK complexes to lysosomes for degradation. Activation of the intrinsic tyrosine kinase activity of RTKs results in autophosphorylation, which is mechanistically coupled to the recruitment of adaptor proteins and conjugation of ubiquitin to RTKs. Ubiquitination serves to mediate interactions of RTKs with sorting machineries both at the cell surface and on endosomes. The pathways and kinetics of RTK endocytic trafficking, molecular mechanisms underlying sorting processes, and examples of deviations from the standard trafficking itinerary in the RTK family are discussed in this work. PMID:23637288

  8. Receptor tyrosine kinases in carcinogenesis.

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    Zhang, Xiao-Ying; Zhang, Pei-Ying

    2016-11-01

    Receptor tyrosine kinases (RTKs) are cell surface glycoproteins with enzymatic activity involved in the regulation of various important functions. In all-important physiological functions including differentiation, cell-cell interactions, survival, proliferation, metabolism, migration and signaling these receptors are the key players of regulation. Additionally, mutations of RTKs or their overexpression have been described in many human cancers and are being explored as a novel avenue for a new therapeutic approach. Some of the deregulated RTKs observed to be significantly affected in cancers included vascular endothelial growth factor receptor, epidermal growth factor receptor, fibroblast growth factor receptor, RTK-like orphan receptor 1 (ROR1) and the platelet-derived growth factor receptor. These deregulated RTKs offer attractive possibilities for the new anticancer therapeutic approach involving specific targeting by monoclonal antibodies as well as kinase. The present review aimed to highlight recent perspectives of RTK ROR1 in cancer.

  9. TYROSINE KINASE INHIBITORS AND PREGNANCY

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    Elisabetta Abruzzese

    2014-04-01

    Full Text Available The management of patients with chronic myeloid leukemia (CML during pregnancy has became recently a matter of continuous debate.  The introduction of the Tyrosine Kinase Inhibitors (TKIs in clinical practice has dramatically changed the prognosis of CML patients.  Patients diagnosed in chronic phase can reasonably expect many years of excellent disease control and good quality of life, as well as a normal life expectancy.  This fact has come the necessity to address issues relating to fertility and pregnancy. Physicians are not infrequently being asked for advice regarding the need for, and or the appropriateness of, stopping treatment in order to conceive. In this report we will review the data published in terms of fertility, conception, pregnancy, pregnancy outcome and illness control for all the approved TKIs, as well as suggest how to manage a planned and/or unplanned pregnancy.

  10. 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.

  11. Conservation and early expression of zebrafish tyrosine kinases support the utility of zebrafish as a model for tyrosine kinase biology.

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    Challa, Anil Kumar; Chatti, Kiranam

    2013-09-01

    Tyrosine kinases have significant roles in cell growth, apoptosis, development, and disease. To explore the use of zebrafish as a vertebrate model for tyrosine kinase signaling and to better understand their roles, we have identified all of the tyrosine kinases encoded in the zebrafish genome and quantified RNA expression of selected tyrosine kinases during early development. Using profile hidden Markov model analysis, we identified 122 zebrafish tyrosine kinase genes and proposed unambiguous gene names where needed. We found them to be organized into 39 nonreceptor and 83 receptor type, and 30 families consistent with human tyrosine kinase family assignments. We found five human tyrosine kinase genes (epha1, bmx, fgr, srm, and insrr) with no identifiable zebrafish ortholog, and one zebrafish gene (yrk) with no identifiable human ortholog. We also found that receptor tyrosine kinase genes were duplicated more often than nonreceptor tyrosine kinase genes in zebrafish. We profiled expression levels of 30 tyrosine kinases representing all families using direct digital detection at different stages during the first 24 hours of development. The profiling experiments clearly indicate regulated expression of tyrosine kinases in the zebrafish, suggesting their role during early embryonic development. In summary, our study has resulted in the first comprehensive description of the zebrafish tyrosine kinome.

  12. Tyrosine kinase BMX phosphorylates phosphotyrosine-primed motif mediating the activation of multiple receptor tyrosine kinases.

    Science.gov (United States)

    Chen, Sen; Jiang, Xinnong; Gewinner, Christina A; Asara, John M; Simon, Nicholas I; Cai, Changmeng; Cantley, Lewis C; Balk, Steven P

    2013-05-28

    The nonreceptor tyrosine kinase BMX (bone marrow tyrosine kinase gene on chromosome X) is abundant in various cell types and activated downstream of phosphatidylinositol-3 kinase (PI3K) and the kinase Src, but its substrates are unknown. Positional scanning peptide library screening revealed a marked preference for a priming phosphorylated tyrosine (pY) in the -1 position, indicating that BMX substrates may include multiple tyrosine kinases that are fully activated by pYpY sites in the kinase domain. BMX phosphorylated focal adhesion kinase (FAK) at Tyr⁵⁷⁷ subsequent to its Src-mediated phosphorylation at Tyr⁵⁷⁶. Loss of BMX by RNA interference or by genetic deletion in mouse embryonic fibroblasts (MEFs) markedly impaired FAK activity. Phosphorylation of the insulin receptor in the kinase domain at Tyr¹¹⁸⁹ and Tyr¹¹⁹⁰, as well as Tyr¹¹⁸⁵, and downstream phosphorylation of the kinase AKT at Thr³⁰⁸ were similarly impaired by BMX deficiency. However, insulin-induced phosphorylation of AKT at Ser⁴⁷³ was not impaired in Bmx knockout MEFs or liver tissue from Bmx knockout mice, which also showed increased insulin-stimulated glucose uptake, possibly because of decreased abundance of the phosphatase PHLPP (PH domain leucine-rich repeat protein phosphatase). Thus, by identifying the pYpY motif as a substrate for BMX, our findings suggest that BMX functions as a central regulator among multiple signaling pathways mediated by tyrosine kinases.

  13. ABL Tyrosine Kinase Stimulates PUMA Protein Expression

    OpenAIRE

    Oon, Chet K

    2016-01-01

    ABL is an ubiquitously expressed non-receptor tyrosine kinase involved in multiple cellular functions including programmed cell death. Upon DNA damage, ABL has been shown to upregulate PUMA, p53 upregulated modulator of apoptosis, and causes downstream mitochondrial intrinsic apoptotic events. However, the mechanism by which ABL regulates PUMA expression remains unknown. We have shown that ABL does not change PUMA protein subcellular localization through immunofluorescence. Through protein an...

  14. Therapeutic Innovations: Tyrosine Kinase Inhibitors in Cancer

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    Nikolaos Dervisis

    2016-01-01

    Full Text Available Conventional cytotoxic chemotherapy involving DNA-interacting agents and indiscriminate cell death is no longer the future of cancer management. While chemotherapy is not likely to completely disappear from the armamentarium; the use of targeted therapies in combination with conventional treatment is becoming the standard of care in human medicine. Tyrosine kinases are pivotal points of functional cellular pathways and have been implicated in malignancy, inflammatory, and immune-mediated diseases. Pharmaceutical interventions targeting aberrant tyrosine kinase signaling has exploded and is the second most important area of drug development. The “Valley of Death” between drug discovery and approval threatens to blunt the enormous strides in cancer management seen thus far. Kinase inhibitors, as targeted small molecules, hold promise in the treatment and diagnosis of cancer. However, there are still many unanswered questions regarding the use of kinase inhibitors in the interpretation and management of cancer. Comparative oncology has the potential to address restrictions and limitations in the advancement in kinase inhibitor therapy.

  15. Targeting Spleen Tyrosine Kinase-Bruton's Tyrosine Kinase Axis for Immunologically Mediated Glomerulonephritis

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    Chen, Jin-Shuen; Chang, Li-Chien; Huang, Shyh-Jer

    2014-01-01

    The importance of B-cell activation and immune complex-mediated Fc-receptor activation in the pathogenesis of immunologically mediated glomerulonephritis has long been recognized. The two nonreceptor tyrosine kinases, spleen tyrosine kinase (Syk) and Bruton's tyrosine kinase (Btk), are primarily expressed by hematopoietic cells, and participate in B-cell-receptor- and Fc-receptor-mediated activation. Pharmacological inhibitors of Syk or Btk are undergoing preclinical development and clinical trials for several immune diseases; and Syk inhibitors have been shown to reduce disease activity in rheumatoid arthritis patients. However, the clinical therapeutic efficacies of these inhibitors in glomerulonephritis have not been evaluated. Herein, we review recent studies of Syk and Btk inhibitors in several experimental primary and secondary glomerulonephritis models. These inhibitors suppressed development of glomerular injury, and also ameliorated established kidney disease. Thus, targeting Syk and Btk signaling pathways is a potential therapeutic strategy for glomerulonephritis, and further evaluation is recommended. PMID:24795896

  16. Tyrosine Kinase Inhibition: An Approach to Drug Development

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    Levitzki, Alexander; Gazit, Aviv

    1995-03-01

    Protein tyrosine kinases (PTKs) regulate cell proliferation, cell differentiation, and signaling processes in the cells of the immune system. Uncontrolled signaling from receptor tyrosine kinases and intracellular tyrosine kinases can lead to inflammatory responses and to diseases such as cancer, atherosclerosis, and psoriasis. Thus, inhibitors that block the activity of tyrosine kinases and the signaling pathways they activate may provide a useful basis for drug development. This article summarizes recent progress in the development of PTK inhibitors and demonstrates their potential use in the treatment of disease.

  17. Receptor Tyrosine Kinase and Tyrosine Kinase Inhibitors: New Hope for Success in Multiple Sclerosis Therapy.

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    Mirshafiey, Abbas; Ghalamfarsa, Ghasem; Asghari, Babak; Azizi, Gholamreza

    2014-07-01

    Receptor tyrosine kinases (RTKs) are essential components of signal transduction pathways that mediate cell-to-cell communication and their function as relay points for signaling pathways. They have a key role in numerous processes that control cellular proliferation and differentiation, regulate cell growth and cellular metabolism, and promote cell survival and apoptosis. Recently, the role of RTKs including TCR, FLT-3, c-Kit, c-Fms, PDGFR, ephrin, neurotrophin receptor, and TAM receptor in autoimmune disorder, especially rheumatoid arthritis and multiple sclerosis has been suggested. In multiple sclerosis pathogenesis, RTKs and their tyrosine kinase enzymes are selective important targets for tyrosine kinase inhibitor (TKI) agents. TKIs, compete with the ATP binding site of the catalytic domain of several tyrosine kinases, and act as small molecules that have a favorable safety profile in disease treatment. Up to now, the efficacy of TKIs in numerous animal models of MS has been demonstrated, but application of these drugs in human diseases should be tested in future clinical trials.

  18. A secreted tyrosine kinase acts in the extracellular environment.

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    Bordoli, Mattia R; Yum, Jina; Breitkopf, Susanne B; Thon, Jonathan N; Italiano, Joseph E; Xiao, Junyu; Worby, Carolyn; Wong, Swee-Kee; Lin, Grace; Edenius, Maja; Keller, Tracy L; Asara, John M; Dixon, Jack E; Yeo, Chang-Yeol; Whitman, Malcolm

    2014-08-28

    Although tyrosine phosphorylation of extracellular proteins has been reported to occur extensively in vivo, no secreted protein tyrosine kinase has been identified. As a result, investigation of the potential role of extracellular tyrosine phosphorylation in physiological and pathological tissue regulation has not been possible. Here, we show that VLK, a putative protein kinase previously shown to be essential in embryonic development, is a secreted protein kinase, with preference for tyrosine, that phosphorylates a broad range of secreted and ER-resident substrate proteins. We find that VLK is rapidly and quantitatively secreted from platelets in response to stimuli and can tyrosine phosphorylate coreleased proteins utilizing endogenous as well as exogenous ATP sources. We propose that discovery of VLK activity provides an explanation for the extensive and conserved pattern of extracellular tyrosine phosphophorylation seen in vivo, and extends the importance of regulated tyrosine phosphorylation into the extracellular environment.

  19. Complexity of Receptor Tyrosine Kinase Signal Processing

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    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

  20. Asymmetric Tyrosine Kinase Arrangements in Activation or Autophosphorylation of Receptor Tyrosine Kinases

    Energy Technology Data Exchange (ETDEWEB)

    J Bae; J Schlessinger

    2011-12-31

    Receptor tyrosine kinases (RTKs) play important roles in the control of many cellular processes including cell proliferation, cell adhesion, angiogenesis, and apoptosis. Ligand-induced dimerization of RTKs leads to autophosphorylation and activation of RTKs. Structural studies have shown that while isolated ectodomains of several RTKs form symmetric dimers the isolated cytoplasmic kinase domains of epidermal growth factor receptor (EGFR) and fibroblast growth factor receptor (FGFR) form asymmetric dimers during their activation. Binding of one kinase molecule of EGFR to a second kinase molecule asymmetrically leads to stimulation of kinase activity and enhanced autophosphorylation. Furthermore, the structures of the kinase domain of FGFR1 and FGFR2 reveal the formation of asymmetric interfaces in the processes of autophosphorylation at their specific phosphotyrosine (pY) sites. Disruption of asymmetric dimer interface of EGFR leads to reduction in enzymatic activity and drastic reduction of autophosphorylation of FGFRs in ligandstimulated live cells. These studies demonstrate that asymmetric dimer formation is as a common phenomenon critical for activation and autophosphorylation of RTKs.

  1. Constitutive Activity in an Ancestral Form of Abl Tyrosine Kinase.

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    Aleem, Saadat U; Craddock, Barbara P; Miller, W Todd

    2015-01-01

    The c-abl proto-oncogene encodes a nonreceptor tyrosine kinase that is found in all metazoans, and is ubiquitously expressed in mammalian tissues. The Abl tyrosine kinase plays important roles in the regulation of mammalian cell physiology. Abl-like kinases have been identified in the genomes of unicellular choanoflagellates, the closest relatives to the Metazoa, and in related unicellular organisms. Here, we have carried out the first characterization of a premetazoan Abl kinase, MbAbl2, from the choanoflagellate Monosiga brevicollis. The enzyme possesses SH3, SH2, and kinase domains in a similar arrangement to its mammalian counterparts, and is an active tyrosine kinase. MbAbl2 lacks the N-terminal myristoylation and cap sequences that are critical regulators of mammalian Abl kinase activity, and we show that MbAbl2 is constitutively active. When expressed in mammalian cells, MbAbl2 strongly phosphorylates cellular proteins on tyrosine, and transforms cells much more potently than mammalian Abl kinase. Thus, MbAbl2 appears to lack the autoinhibitory mechanism that tightly constrains the activity of mammalian Abl kinases, suggesting that this regulatory apparatus arose more recently in metazoan evolution.

  2. Constitutive Activity in an Ancestral Form of Abl Tyrosine Kinase.

    Directory of Open Access Journals (Sweden)

    Saadat U Aleem

    Full Text Available The c-abl proto-oncogene encodes a nonreceptor tyrosine kinase that is found in all metazoans, and is ubiquitously expressed in mammalian tissues. The Abl tyrosine kinase plays important roles in the regulation of mammalian cell physiology. Abl-like kinases have been identified in the genomes of unicellular choanoflagellates, the closest relatives to the Metazoa, and in related unicellular organisms. Here, we have carried out the first characterization of a premetazoan Abl kinase, MbAbl2, from the choanoflagellate Monosiga brevicollis. The enzyme possesses SH3, SH2, and kinase domains in a similar arrangement to its mammalian counterparts, and is an active tyrosine kinase. MbAbl2 lacks the N-terminal myristoylation and cap sequences that are critical regulators of mammalian Abl kinase activity, and we show that MbAbl2 is constitutively active. When expressed in mammalian cells, MbAbl2 strongly phosphorylates cellular proteins on tyrosine, and transforms cells much more potently than mammalian Abl kinase. Thus, MbAbl2 appears to lack the autoinhibitory mechanism that tightly constrains the activity of mammalian Abl kinases, suggesting that this regulatory apparatus arose more recently in metazoan evolution.

  3. A novel proteomic approach for specific identification of tyrosine kinase substrates using [13C]tyrosine.

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    Ibarrola, Nieves; Molina, Henrik; Iwahori, Akiko; Pandey, Akhilesh

    2004-04-16

    Proteomic studies to find substrates of tyrosine kinases generally rely on identification of protein bands that are "pulled down" by antiphosphotyrosine antibodies from ligand-stimulated samples. One can obtain erroneous results from such experiments because of two major reasons. First, some proteins might be basally phosphorylated on tyrosine residues in the absence of ligand stimulation. Second, proteins can bind non-specifically to the antibodies or the affinity matrix. Induction of phosphorylation of proteins by ligand must therefore be confirmed by a different approach, which is not always feasible. We have developed a novel proteomic approach to identify substrates of tyrosine kinases in signaling pathways studies based on in vivo labeling of proteins with "light" (12C-labeled) or "heavy" (13C-labeled) tyrosine. This stable isotope labeling in cell culture method enables the unequivocal identification of tyrosine kinase substrates, as peptides derived from true substrates give rise to a unique signature in a mass spectrometry experiment. By using this approach, from a single experiment, we have successfully identified several known substrates of insulin signaling pathway and a novel substrate, polymerase I and transcript release factor, a protein that is implicated in the control of RNA metabolism and regulation of type I collagen promoters. This approach is amenable to high throughput global studies as it simplifies the specific identification of substrates of tyrosine kinases as well as serine/threonine kinases using mass spectrometry.

  4. Small molecule tyrosine kinase inhibitors in pancreatic cancer

    Directory of Open Access Journals (Sweden)

    Sachin Gupta

    2008-10-01

    Full Text Available Sachin Gupta, Bassel F El-RayesDepartment of Hematology/Oncology, Karmanos Cancer Institute, Wayne State University, MI, USAAbstract: Pancreatic cancer has proven to be chemo-resistant, with gemcitabine being the only cytotoxic agent approved for advanced pancreatic cancer since 1996. Tyrosine kinase inhibitors represent a newer generation of chemotherapeutic agents targeting specific tumor pathways associated with carcinogenesis including cell cycle control, signal transduction, apoptosis and angiogenesis. These agents present a more selective way of treating pancreatic cancer. Erlotinib is the prototype of the tyrosine kinase inhibitors with proven efficacy in advanced pancreatic cancer and has been recently approved in that setting. Multiple other tyrosine kinase inhibitors targeting the VEGFR, PDGFR, and Src kinases are in various phases of clinical trials testing. The preliminary results of these trials have been disappointing. Current challenges in pancreatic cancer clinical trials testing include improving patient selection, identifying effective combinations, improving the predictive value of current preclinical models and better study designs. This review summarizes the present clinical development of tyrosine kinase inhibitors in pancreatic cancer and strategies for future drug development.Keywords: pancreatic cancer, erlotinib, tyrosine kinase inhibitors

  5. Tyrosine kinase blockers: new hope for successful cancer therapy.

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    Pytel, Dariusz; Sliwinski, Tomasz; Poplawski, Tomasz; Ferriola, Deborah; Majsterek, Ireneusz

    2009-01-01

    Tyrosine kinases (TKs) are attractive targets for cancer therapy, as quite often their abnormal signaling has been linked with tumor development and growth. Constitutive activated TKs stimulate multiple signaling pathways responsible for DNA repair, apoptosis, and cell proliferation. During the last few years, thorough analysis of the mechanism underlying tyrosine kinase's activity led to novel cancer therapy using TKs blockers. These drugs are remarkably effective in the treatment of various human tumors including head and neck, gastric, prostate and breast cancer and leukemias. The most successful example of kinase blockers is Imatinib (Imatinib mesylate, Gleevec, STI571), the inhibitor of Bcr/Abl oncoprotein, which has become a first-line therapy for chronic myelogenous leukemia. The introduction of STI571 for the treatment of leukemia in clinical oncology has had a dramatic impact on how this disease is currently managed. Others kinase inhibitors used recently in cancer therapy include Dasatinib (BMS-354825) specific for ABL non-receptor cytoplasmic kinase, Gefitinib (Iressa), Erlotinib (OSI-774, Tarceva) and Sunitinib (SU 11248, Sutent) specific for VEGF receptor kinase, AMN107 (Nilotinib) and INNO-406 (NS-187) specific for c-KIT kinase. The following TK blockers for treatment of various human tumors are in clinical development: Lapatinib (Lapatinib ditosylate, Tykerb, GW-572016), Canertinib (CI-1033), Zactima (ZD6474), Vatalanib (PTK787/ZK 222584), Sorafenib (Bay 43-9006, Nexavar), and Leflunomide (SU101, Arava). Herein, we discuss the chemistry, biological activity and clinical potential of new drugs with tyrosine kinase blockers for cancer treatment.

  6. Haemophilus ducreyi LspA proteins are tyrosine phosphorylated by macrophage-encoded protein tyrosine kinases.

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    Deng, Kaiping; Mock, Jason R; Greenberg, Steven; van Oers, Nicolai S C; Hansen, Eric J

    2008-10-01

    The LspA proteins (LspA1 and LspA2) of Haemophilus ducreyi are necessary for this pathogen to inhibit the phagocytic activity of macrophage cell lines, an event that can be correlated with a reduction in the level of active Src family protein tyrosine kinases (PTKs) in these eukaryotic cells. During studies investigating this inhibitory mechanism, it was discovered that the LspA proteins themselves were tyrosine phosphorylated after wild-type H. ducreyi cells were incubated with macrophages. LspA proteins in cell-free concentrated H. ducreyi culture supernatant fluid could also be tyrosine phosphorylated by macrophages. This ability to tyrosine phosphorylate the LspA proteins was not limited to immune cell lineages but could be accomplished by both HeLa and COS-7 cells. Kinase inhibitor studies with macrophages demonstrated that the Src family PTKs were required for this tyrosine phosphorylation activity. In silico methods and site-directed mutagenesis were used to identify EPIYG and EPVYA motifs in LspA1 that contained tyrosines that were targets for phosphorylation. A total of four tyrosines could be phosphorylated in LspA1, with LspA2 containing eight predicted tyrosine phosphorylation motifs. Purified LspA1 fusion proteins containing either the EPIYG or EPVYA motifs were shown to be phosphorylated by purified Src PTK in vitro. Macrophage lysates could also tyrosine phosphorylate the LspA proteins and an LspA1 fusion protein via a mechanism that was dependent on the presence of both divalent cations and ATP. Several motifs known to interact with or otherwise affect eukaryotic kinases were identified in the LspA proteins.

  7. Old Tyrosine Kinase Inhibitors and Newcomers in Gastrointestinal Cancer Treatment.

    Science.gov (United States)

    Giordani, Erika; Zoratto, Federica; Strudel, Martina; Papa, Anselmo; Rossi, Luigi; Minozzi, Marina; Caruso, Davide; Zaccarelli, Eleonora; Verrico, Monica; Tomao, Silverio

    2016-01-01

    Gastrointestinal cancer treatment is based more on molecular biology that has provided increasing knowledge about cancer pathogenesis on which targeted therapy is being developed. Precisely, targeted therapy is defined as a "type of treatment that uses drugs, such as monoclonal antibodies or tyrosine kinase inhibitors, to identify and attack specific cancer cells". Nowadays, the United States Food and Drug Administration has approved many targeted therapies for gastrointestinal cancer treatment, as many are in various phases of development as well. In a previous review we discussed the main monoclonal antibodies used and studied in gastrointestinal cancer. In addition to monoclonal antibodies, tyrosine kinase inhibitors represent another class of targeted therapy and following the approval of imatinib for gastrointestinal stromal tumours, other tyrosine kinase inhibitors have been approved for gastrointestinal cancers treatment such as sunitinib, regoragenib, sorafenib and erlotinib. Moving forward, the purpose of this review is to focus on the efficacy data of main tyrosine kinase inhibitors commonly used in the personalized treatment of each gastrointestinal tumour and to provide a comprehensive overview about experimental targeted therapies ongoing in this setting.

  8. Drug-drug interactions with tyrosine-kinase inhibitors

    NARCIS (Netherlands)

    Croes, Sander; de Vries, Frank

    2014-01-01

    In their Review, Roelof van Leeuwen and colleagues1 recommend various dose adjustments during concomitant use of tyrosine-kinase inhibitors and drugs that inhibit or induce cytochrome P450 3A4 (CYP3A4).1 Most information is taken from the US Food and Drug Administration (FDA)'s drug label or the Eur

  9. A Molecular Brake in the Kinase Hinge Region Regulates the Activity of Receptor Tyrosine Kinases

    Energy Technology Data Exchange (ETDEWEB)

    Chen,H.; Ma, J.; Li, W.; Eliseenkova, A.; Xu, C.; Neubert, T.; Miller, W.; Mohammadi, M.

    2007-01-01

    Activating mutations in the tyrosine kinase domain of receptor tyrosine kinases (RTKs) cause cancer and skeletal disorders. Comparison of the crystal structures of unphosphorylated and phosphorylated wild-type FGFR2 kinase domains with those of seven unphosphorylated pathogenic mutants reveals an autoinhibitory 'molecular brake' mediated by a triad of residues in the kinase hinge region of all FGFRs. Structural analysis shows that many other RTKs, including PDGFRs, VEGFRs, KIT, CSF1R, FLT3, TEK, and TIE, are also subject to regulation by this brake. Pathogenic mutations activate FGFRs and other RTKs by disengaging the brake either directly or indirectly.

  10. 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 and the regulation of macrophage activation. Authors Co

  11. Novel Bruton's tyrosine kinase inhibitors currently in development

    Directory of Open Access Journals (Sweden)

    D'Cruz OJ

    2013-03-01

    Full Text Available Osmond J D'Cruz,1 Fatih M Uckun1,21Children's Center for Cancer and Blood Diseases, Children's Hospital Los Angeles, Los Angeles, CA, USA; 2Department of Pediatrics, University of Southern California, Los Angeles, CA, USAAbstract: Bruton's tyrosine kinase (Btk is intimately involved in multiple signal-transduction pathways regulating survival, activation, proliferation, and differentiation of B-lineage lymphoid cells. Btk is overexpressed and constitutively active in several B-lineage lymphoid malignancies. Btk has emerged as a new antiapoptotic molecular target for treatment of B-lineage leukemias and lymphomas. Preclinical and early clinical results indicate that Btk inhibitors may be useful in the treatment of leukemias and lymphomas.Keywords: tyrosine kinase, personalized therapy, kinase inhibitors, Btk, leukemia, lymphoma

  12. Proteolytic activation of ETK/Bmx tyrosine kinase by caspases.

    Science.gov (United States)

    Wu, Y M; Huang, C L; Kung, H J; Huang, C Y

    2001-05-25

    Etk/Bmx is a member of the Btk/Tec family of kinases, which are characterized by having a pleckstrin homology domain at the N terminus, in addition to the Src homology 3 (SH3), SH2, and the catalytic domains, shared with the Src family kinases. Etk, or Btk kinases in general, has been implicated in the regulation of apoptosis. To test whether Etk is the substrate for caspases during apoptosis, in vitro translated [(35)S]methionine-labeled Etk was incubated with different apoptotic extracts and recombinant caspases, respectively. Results showed that Etk was proteolyzed in all conditions tested with identical cleavage patterns. Caspase-mediated cleavage of Etk generated a C-terminal fragment, containing the complete SH2 and tyrosine kinase domains, but without intact pleckstrin homology and SH3 domains. This fragment has 4-fold higher kinase activity than that of the full-length Etk. Ectopic expression of the C-terminal fragment of Etk sensitized the PC3 prostate cancer cells to apoptosis in response to apoptosis-inducing stimuli. The finding, together with an earlier report that Etk is potentially antiapoptotic, suggests that Etk may serve as an apoptotic switch, depending on the forms of Etk existing inside the cells. To our knowledge, this is the first case where the activity of a tyrosine kinase is induced by caspase cleavage.

  13. Spatial regulation of receptor tyrosine kinases in development and cancer

    OpenAIRE

    Casaletto, Jessica B.; McClatchey, Andrea I.

    2012-01-01

    During development and tissue homeostasis, patterns of cellular organization, proliferation, and movement are highly choreographed. Receptor tyrosine kinases (RTKs) play a critical role in establishing these patterns. Individual cells and tissues exhibit tight spatial control of the RTKs that they express, enabling tissue morphogenesis and function while preventing unwarranted cell division and migration that can contribute to tumorigenesis. Indeed, RTKs are deregulated in most human cancers ...

  14. Novel Bruton’s tyrosine kinase inhibitors currently in development

    Science.gov (United States)

    D’Cruz, Osmond J; Uckun, Fatih M

    2013-01-01

    Bruton’s tyrosine kinase (Btk) is intimately involved in multiple signal-transduction pathways regulating survival, activation, proliferation, and differentiation of B-lineage lymphoid cells. Btk is overexpressed and constitutively active in several B-lineage lymphoid malignancies. Btk has emerged as a new antiapoptotic molecular target for treatment of B-lineage leukemias and lymphomas. Preclinical and early clinical results indicate that Btk inhibitors may be useful in the treatment of leukemias and lymphomas. PMID:23493945

  15. Eph-mediated tyrosine phosphorylation of citron kinase controls abscission

    Science.gov (United States)

    Jungas, Thomas; Perchey, Renaud T.; Fawal, Mohamad; Callot, Caroline; Froment, Carine; Burlet-Schiltz, Odile; Besson, Arnaud

    2016-01-01

    Cytokinesis is the last step of cell division, culminating in the physical separation of daughter cells at the end of mitosis. Cytokinesis is a tightly regulated process that until recently was mostly viewed as a cell-autonomous event. Here, we investigated the role of Ephrin/Eph signaling, a well-known local cell-to-cell communication pathway, in cell division. We show that activation of Eph signaling in vitro leads to multinucleation and polyploidy, and we demonstrate that this is caused by alteration of the ultimate step of cytokinesis, abscission. Control of abscission requires Eph kinase activity, and Src and citron kinase (CitK) are downstream effectors in the Eph-induced signal transduction cascade. CitK is phosphorylated on tyrosines in neural progenitors in vivo, and Src kinase directly phosphorylates CitK. We have identified the specific tyrosine residues of CitK that are phosphorylated and show that tyrosine phosphorylation of CitK impairs cytokinesis. Finally, we show that, similar to CitK, Ephrin/Eph signaling controls neuronal ploidy in the developing neocortex. Our study indicates that CitK integrates intracellular and extracellular signals provided by the local environment to coordinate completion of cytokinesis. PMID:27551053

  16. Chronic Myeloid Leukemia in the Era of Tyrosine Kinase Inhibitors: An Evolving Paradigm of Molecularly Targeted Therapy.

    Science.gov (United States)

    Ali, Mohamed A M

    2016-08-01

    Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm, characterized by the unrestrained expansion of pluripotent hematopoietic stem cells. CML was the first malignancy in which a unique chromosomal abnormality was identified and a pathophysiologic association was suggested. The hallmark of CML is a reciprocal chromosomal translocation between the long arms of chromosomes 9 and 22, t(9; 22)(q34; q11), creating a derivative 9q+ and a shortened 22q-. The latter, known as the Philadelphia (Ph) chromosome, harbors the breakpoint cluster region-abelson (BCR-ABL) fusion gene, encoding the constitutively active BCR-ABL tyrosine kinase that is necessary and sufficient for initiating CML. The successful implementation of tyrosine kinase inhibitors (TKIs) for the treatment of CML remains a flagship for molecularly targeted therapy in cancer. TKIs have changed the clinical course of CML; however, some patients nonetheless demonstrate primary or secondary resistance to such therapy and require an alternative therapeutic strategy. Therefore, the assessment of early response to treatment with TKIs has become an important tool in the clinical monitoring of CML patients. Although mutations in the BCR-ABL have proven to be the most prominent mechanism of resistance to TKIs, other mechanisms-either rendering the leukemic cells still dependent on BCR-ABL activity or supporting oncogenic properties of the leukemic cells independent of BCR-ABL signaling-have been identified. This article provides an overview of the current understanding of CML pathogenesis; recommendations for diagnostic tools, treatment strategies, and management guidelines; and highlights the BCR-ABL-dependent and -independent mechanisms that contribute to the development of resistance to TKIs.

  17. Robust versatile tyrosine kinase assay for HTS in drug discovery

    Science.gov (United States)

    Deshpande, Sudhir S.; Mineyev, I.; Owicki, John C.

    1999-04-01

    A fluorescence polarization assay was developed as an alternative to the radiolabeled SPA assays currently used to monitor the activity of tyrosine kinases in drug discovery. The assay can be used with enzymes having substrate specificity similar to that of the insulin receptor, the EGF receptor and the Src kinase receptor enzymes. The assay is easy to configure in 96, 384 and 1536-well microplates in assay volumes ranging from (mu) L with minimal efforts. The reconstituted reagents are stable for up to 24 hr at ambient temperatures, thereby minimizing the need for replenishing the stock solutions during the course of a high-throughput screen. Because of the stability and equilibrium kinetics, the assay allows the user the luxury of scheduling the reading of plates any time up to 24 hr after the completion of the assay without substantial deterioration in the assay signal. The antibody and the tracer solutions can also be premixed and added as a preformed complex in a single step. The performance of the assay with the insulin receptor kinase is described. In addition, given the diversity of the substrates used in measuring the activity of different tyrosine kinases, LJL's on-going efforts to provide different antibodies of wide ranging specificity and sensitivity are described.

  18. BRET biosensor analysis of receptor tyrosine kinase functionality

    Directory of Open Access Journals (Sweden)

    Sana eSiddiqui

    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.

  19. Current understanding of tyrosine kinase BMX in inflammation and its inhibitors

    Directory of Open Access Journals (Sweden)

    Le Qiu

    2014-07-01

    Full Text Available Tec family kinases, which include tyrosine kinase expressed in hepatocellular carcinoma (TEC, Bruton's tyrosine kinase (BTK, interleukin (IL-2-inducible T-cell kinase (ITK, tyrosine-protein kinase (TXK, and bone marrow tyrosine kinase on chromosome X (BMX, are the second largest group of non-receptor tyrosine kinases and have a highly conserved carboxyl-terminal kinase domain. BMX was identified in human bone marrow cells, and was demonstrated to have been expressed in myeloid hematopoietic lineages cells, endothelial cells, and several types of cancers. Significant progress in this area during the last decade revealed an important role for BMX in inflammation and oncologic disorders. This review focuses on BMX biology, its role in inflammation and possible signaling pathways, and the potential of selective BMX inhibitors.

  20. Current understanding of tyrosine kinase BMX in inflammation and its inhibitors.

    Science.gov (United States)

    Qiu, Le; Wang, Fei; Liu, Sheng; Chen, Xu-Lin

    2014-01-01

    Tec family kinases, which include tyrosine kinase expressed in hepatocellular carcinoma (TEC), Bruton's tyrosine kinase (BTK), interleukin (IL)-2-inducible T-cell kinase (ITK), tyrosine-protein kinase (TXK), and bone marrow tyrosine kinase on chromosome X (BMX), are the second largest group of non-receptor tyrosine kinases and have a highly conserved carboxyl-terminal kinase domain. BMX was identified in human bone marrow cells, and was demonstrated to have been expressed in myeloid hematopoietic lineages cells, endothelial cells, and several types of cancers. Significant progress in this area during the last decade revealed an important role for BMX in inflammation and oncologic disorders. This review focuses on BMX biology, its role in inflammation and possible signaling pathways, and the potential of selective BMX inhibitors.

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

    Directory of Open Access Journals (Sweden)

    Marion eMorel

    2014-07-01

    Full Text Available 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 the recent years, it has been shown that receptor tyrosine kinases (RTK signaling was active in reproductive organs and that it could regulate sexual maturation of schistosomes and egg production. This opens interesting perspectives for the control of transmission and pathogenesis of schistosomiasis based on new therapies targeting schistosome RTKs. This review relates the numerous data showing the major roles of kinase signaling in schistosome reproduction. It describes the conserved and particular features of schistosome RTKs, their implication in gametogenesis and reproduction processes and summarizes recent works indicating that RTKs and their signaling partners are interesting chemotherapeutical targets in new programs of control.

  2. Genomic organization of Bruton`s tyrosine kinase

    Energy Technology Data Exchange (ETDEWEB)

    Rohrer, J.; Conley, M.E. [Univ. of Tennessee, Memphis, TN (United States)

    1994-09-01

    Bruton`s tyrosine kinase (Btk), is a nonreceptor tyrosine kinase that has been identified as the defective gene in X-linked agammaglobulinemia (XLA). XLA patients have profound hypogammaglobulinemia and markedly reduced numbers of B cells while their T cell and phagocyte numbers remain normal. To determine the genomic organization of Btk, intron/exon borders were identified by sequencing cosmid DNA using cDNA primers. Nineteen exons spanning 37 kb of genomic DNA were identified. All the intron/exon splice junctions followed the GT/AG rule. The translational ATG start codon was in exon 2 which was 6 kb downstream of exon 1. Exon 19, 519 bp in length and 3.8 kb distal to exon 18, was the largest exon and included the 450 bp of the 3{prime} untranslated region. Exons 6 through 18 formed the largest cluster of exons with no intron being longer than 1550 bp. There was no apparent correlation between the exon boundaries of Btk and the functional domains of the protein or the exon boundaries of src, the nonreceptor protein tyrosine kinase prototype. The region 500 bp upstream of the presumed transcriptional start site was sequenced and found to have a G+C content of 52%. No TATA-type promoter elements in the -20 bp to -30 bp region were identified. However, at position -48 bp, a TGTGAA motif was found that bears some similarity to the TATA box. This sequence was preceded by a perfect inverted CCAAT box at position -90 bp. Three retinoic acid binding sites were also identified at positions -50 bp, -83 bp and -197 bp. Defining the genomic structure of Btk will permit us to identify regulatory elements in this gene and to identify mutations in genomic DNA of patients with XLA.

  3. ABNORMAL PROTEIN TYROSINE KINASES ASSOCIATED WITH HUMAN HAEMATOLOGICAL MALIGNANCIES

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Objective: To survey the role of protein tyrosine kinases (PTKs) in the pathogenesis of several hematopoietic malignancies. Methods: By reviewing the published laboratory and clinical studies on PTK-related oncoproteins and their causative role in some leukemias and lymphomas. Results: Protein tyrosine kinases are key participants in signal transduction pathways that regulate cellular growth, activation and differentiations. Aberrant PTK activity resulting from gene mutation (often accompanying chromosome translocation) plays an etiologic role in several clonal hematopoietic malignancies. For example, the PTK product of the BCR-ABL fusion gene resulting from the t (9; 22) translocation exhibits several fold higher tyrosine kinase activity than the product of the ABL gene. Evidence suggests that the BCR-ABL oncoprotein alone is sufficient to case chronic myelogenous leukemia (CML) and other Ph positive acute leukemia. PTK over-activity resulting from chromosomal translocations creating TEL-ABL, TEL-JAK2 and TEL-PDGFR( fusion proteins plays an important role in the pathogenesis of other types of leukemia. Another example occurs in anaplastic large cell lymphoma (ALCL). Experimental and clinical evidences indicate that translocations involving ALK gene on chromosome 2p23, most commonly resulting in an NPM-ALK fusion oncogene, result in constitutive activation of ALK and cause ALCL. This group of lymphomas is now named ALK positive lymphoma or ALKoma. Conclusion: Genetic lesions creating aberrant fusion proteins that result in excessive PTK activity are increasingly being recognized as central to the pathogenesis of hemotopoietic malignancies. These chimeric PTK molecules represent attractive disease-specific targets against which new classes therapeutic agents are being developed.

  4. Targeted Inhibition of Multiple Receptor Tyrosine Kinases in Mesothelioma

    Directory of Open Access Journals (Sweden)

    Wen-Bin Ou

    2011-01-01

    Full Text Available The receptor tyrosine kinases (RTKs epidermal growth factor receptor (EGFR and MET are activated in subsets of mesothelioma, suggesting that these kinases might represent novel therapeutic targets in this notoriously chemotherapy-resistant cancer. However, clinical trials have shown little activity for EGFR inhibitors in mesothelioma. Despite the evidence for RTK activation in mesothelioma pathogenesis, it is unclear whether transforming activity is dependent on an individual kinase oncoprotein or the coordinated activity of multiple kinases. Using phospho-RTK and immunoblot assays, we herein demonstrate activation of multiple RTKs (EGFR, MET, AXL, and ERBB3 in individual mesothelioma cell lines but not in normal mesothelioma cells. Inhibition of mesothelioma multi-RTK signaling was accomplished using combinations of RTK direct inhibitors or by inhibition of the RTK chaperone, heat shock protein 90 (HSP90. Multi-RTK inhibition by the HSP90 inhibitor 17-allyloamino-17demethoxygeldanamycin (17-AAG had a substantially greater effect on mesothelioma proliferation and survival compared with inhibition of individual activated RTKs. HSP90 inhibition also suppressed phosphorylation of down-stream signaling intermediates (AKT, mitogen-activated protein kinase, and S6; upregulated the p53, p21, and p27 cell cycle checkpoints; induced G2 phase arrest; induced caspase 3/7 activity; and led to an increase in the sub-G1 apoptotic population. These compelling proapoptotic and antiproliferative responses indicate that HSP90 inhibition warrants clinical evaluation as a novel therapeutic strategy in mesothelioma.

  5. CDPKs are dual-specificity protein kinases and tyrosine autophosphorylation attenuates kinase activity.

    Science.gov (United States)

    Oh, Man-Ho; Wu, Xia; Kim, Hyoung Seok; Harper, Jeffrey F; Zielinski, Raymond E; Clouse, Steven D; Huber, Steven C

    2012-11-30

    Although calcium-dependent protein kinases (CDPKs or CPKs) are classified as serine/threonine protein kinases, autophosphorylation on tyrosine residues was observed for soybean CDPKβ and several Arabidopsis isoforms (AtCPK4 and AtCPK34). We identified Ser-8, Thr-17, Tyr-24 (in the kinase domain), Ser-304, and Ser-358 as autophosphorylation sites of His(6)-GmCDPKβ. Overall autophosphorylation increased kinase activity with synthetic peptides, but autophosphorylation of Tyr-24 appears to attenuate kinase activity based on studies with the Y24F directed mutant. While much remains to be done, it is clear that several CDPKs are dual-specificity kinases, which raises the possibility that phosphotyrosine signaling may play a role in Ca(2+)/CDPK-mediated processes. Published by Elsevier B.V.

  6. Analysis of receptor tyrosine kinase internalization using flow cytometry.

    Science.gov (United States)

    Li, Ning; Hill, Kristen S; Elferink, Lisa A

    2008-01-01

    The internalization of activated receptor tyrosine kinases (RTKs) by endocytosis and their subsequent down regulation in lysosomes plays a critical role in regulating the duration and intensity of downstream signaling events. Uncoupling of the RTK cMet from ligand-induced degradation was recently shown to correlate with sustained receptor signaling and increased cell tumorigenicity, suggesting that the corruption of these endocytic mechanisms could contribute to increased cMet signaling in metastatic cancers. To understand how cMet signaling for normal cell growth is controlled by endocytosis and how these mechanisms are dysregulated in metastatic cancers, we developed flow cytometry-based assays to examine cMet internalization.

  7. Signaling Network Map of Endothelial TEK Tyrosine Kinase

    Directory of Open Access Journals (Sweden)

    Aafaque Ahmad Khan

    2014-01-01

    Full Text Available TEK tyrosine kinase is primarily expressed on endothelial cells and is most commonly referred to as TIE2. TIE2 is a receptor tyrosine kinase modulated by its ligands, angiopoietins, to regulate the development and remodeling of vascular system. It is also one of the critical pathways associated with tumor angiogenesis and familial venous malformations. Apart from the vascular system, TIE2 signaling is also associated with postnatal hematopoiesis. Despite the involvement of TIE2-angiopoietin system in several diseases, the downstream molecular events of TIE2-angiopoietin signaling are not reported in any pathway repository. Therefore, carrying out a detailed review of published literature, we have documented molecular signaling events mediated by TIE2 in response to angiopoietins and developed a network map of TIE2 signaling. The pathway information is freely available to the scientific community through NetPath, a manually curated resource of signaling pathways. We hope that this pathway resource will provide an in-depth view of TIE2-angiopoietin signaling and will lead to identification of potential therapeutic targets for TIE2-angiopoietin associated disorders.

  8. Bruton Tyrosine Kinase-Dependent Immune Cell Cross-talk Drives Pancreas Cancer

    National Research Council Canada - National Science Library

    Gunderson, Andrew J; Kaneda, Megan M; Tsujikawa, Takahiro; Nguyen, Abraham V; Affara, Nesrine I; Ruffell, Brian; Gorjestani, Sara; Liudahl, Shannon M; Truitt, Morgan; Olson, Peter; Kim, Grace; Hanahan, Douglas; Tempero, Margaret A; Sheppard, Brett; Irving, Bryan; Chang, Betty Y; Varner, Judith A; Coussens, Lisa M

    2016-01-01

    .... Here, we report that targeting Bruton tyrosine kinase (BTK), a key B-cell and macrophage kinase, restores T cell-dependent antitumor immune responses, thereby inhibiting PDAC growth and improving responsiveness to standard-of-care chemotherapy...

  9. 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.

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

    Science.gov (United States)

    Mezquita, Belén; Mezquita, Pau; Pau, Montserrat; Mezquita, Jovita; Mezquita, Cristóbal

    2014-02-14

    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.

  11. Bosutinib induced pleural effusions: Case report and review of tyrosine kinase inhibitors induced pulmonary toxicity

    Directory of Open Access Journals (Sweden)

    Natalia I. Moguillansky, MD

    2017-01-01

    Full Text Available Tyrosine kinase inhibitors are known to cause pulmonary complications. We report a case of bosutinib related bilateral pleural effusions in a patient with chronic myeloid leukemia. Characteristics of the pleural fluid are presented. We also discuss other tyrosine kinase inhibitors induced pulmonary toxicities, including pulmonary hypertension and interstitial lung disease.

  12. Function of Bruton's tyrosine kinase during B cell development is partially independent of its catalytic activity

    NARCIS (Netherlands)

    S. Middendorp; G.M. Dingjan (Gemma); A. Maas (Alex); K. Dahlenborg; R.W. Hendriks (Rudi)

    2003-01-01

    textabstractThe Tec family member Bruton's tyrosine kinase (Btk) is a cytoplasmic protein tyrosine kinase that transduces signals from the pre-B and B cell receptor (BCR). Btk is involved in pre-B cell maturation by regulating IL-7 responsiveness, cell surface phenotype changes,

  13. Function of Bruton's tyrosine kinase during B cell development is partially independent of its catalytic activity

    NARCIS (Netherlands)

    S. Middendorp; G.M. Dingjan (Gemma); A. Maas (Alex); K. Dahlenborg; R.W. Hendriks (Rudi)

    2003-01-01

    textabstractThe Tec family member Bruton's tyrosine kinase (Btk) is a cytoplasmic protein tyrosine kinase that transduces signals from the pre-B and B cell receptor (BCR). Btk is involved in pre-B cell maturation by regulating IL-7 responsiveness, cell surface phenotype changes, an

  14. Terreic Acid, a Quinone Epoxide Inhibitor of Bruton's Tyrosine Kinase

    Science.gov (United States)

    Kawakami, Yuko; Hartman, Stephen E.; Kinoshita, Eiji; Suzuki, Hidefumi; Kitaura, Jiro; Yao, Libo; Inagaki, Naoki; Franco, Alessandra; Hata, Daisuke; Maeda-Yamamoto, Mari; Fukamachi, Hiromi; Nagai, Hiroichi; Kawakami, Toshiaki

    1999-03-01

    Bruton's tyrosine kinase (Btk) plays pivotal roles in mast cell activation as well as in B cell development. Btk mutations lead to severe impairments in proinflammatory cytokine production induced by cross-linking of high-affinity IgE receptor on mast cells. By using an in vitro assay to measure the activity that blocks the interaction between protein kinase C and the pleckstrin homology domain of Btk, terreic acid (TA) was identified and characterized in this study. This quinone epoxide specifically inhibited the enzymatic activity of Btk in mast cells and cell-free assays. TA faithfully recapitulated the phenotypic defects of btk mutant mast cells in high-affinity IgE receptor-stimulated wild-type mast cells without affecting the enzymatic activities and expressions of many other signaling molecules, including those of protein kinase C. Therefore, this study confirmed the important roles of Btk in mast cell functions and showed the usefulness of TA in probing into the functions of Btk in mast cells and other immune cell systems. Another insight obtained from this study is that the screening method used to identify TA is a useful approach to finding more efficacious Btk inhibitors.

  15. Protein tyrosine kinase and mitogen-activated protein kinase signalling pathways contribute to differences in heterophil-mediated innate immune responsiveness between two lines of broilers

    Science.gov (United States)

    Protein tyrosine phosphorylation mediates signal transduction of cellular processes, with protein tyrosine kinases (PTKs) regulating virtually all signaling events. The mitogen-activated protein kinase (MAPK) super-family consists of three conserved pathways that convert receptor activation into ce...

  16. The Receptor Tyrosine Kinase AXL in Cancer Progression

    Directory of Open Access Journals (Sweden)

    Erinn B. Rankin

    2016-11-01

    Full Text Available The AXL receptor tyrosine kinase (AXL has emerged as a promising therapeutic target for cancer therapy. Recent studies have revealed a central role of AXL signaling in tumor proliferation, survival, stem cell phenotype, metastasis, and resistance to cancer therapy. Moreover, AXL is expressed within cellular components of the tumor microenvironment where AXL signaling contributes to the immunosuppressive and protumorigenic phenotypes. A variety of AXL inhibitors have been developed and are efficacious in preclinical studies. These agents offer new opportunities for therapeutic intervention in the prevention and treatment of advanced disease. Here we review the literature that has illuminated the cellular and molecular mechanisms by which AXL signaling promotes tumor progression and we will discuss the therapeutic potential of AXL inhibition for cancer therapy.

  17. Recent developments in receptor tyrosine kinases targeted anticancer therapy

    Directory of Open Access Journals (Sweden)

    Samir H. Raval

    2016-01-01

    Full Text Available Novel concepts and understanding of receptors lead to discoveries and optimization of many small molecules and antibodies as anti-cancerous drugs. Receptor tyrosine kinases (RTKs are such a promising class of receptors under the investigation in past three decades. RTKs are one of the essential mediators of cell signaling mechanism for various cellular processes. Transformations such as overexpression, dysregulation, or mutations of RTKs may result into malignancy, and thus are an important target for anticancer therapy. Numerous subfamilies of RTKs, such as epidermal growth factor receptor, vascular endothelial growth factor receptor, fibroblast growth factor receptors, insulin-like growth factor receptor, and hepatocyte growth factor receptor, have been being investigated in recent years as target for anticancer therapy. The present review focuses several small molecules drugs as well as monoclonal antibodies targeting aforesaid subfamilies either approved or under investigation to treat the various cancers.

  18. Precision Therapy for Lung Cancer: Tyrosine Kinase Inhibitors and Beyond.

    Science.gov (United States)

    Rajan, Arun; Schrump, David S

    2015-01-01

    For patients with advanced cancers there has been a concerted effort to transition from a generic treatment paradigm to one based on tumor-specific biologic, and patient-specific clinical characteristics. This approach, known as precision therapy has been made possible owing to widespread availability and a reduction in the cost of cutting-edge technologies that are used to study the genomic, proteomic, and metabolic attributes of individual tumors. This review traces the evolution of precision therapy for lung cancer from the identification of molecular subsets of the disease to the development and approval of tyrosine kinase, as well as immune checkpoint inhibitors for lung cancer therapy. Challenges of the precision therapy era including the emergence of acquired resistance, identification of untargetable mutations, and the effect on clinical trial design are discussed. We conclude by highlighting newer applications for the concept of precision therapy.

  19. Tyrosine Kinase Receptor Landscape in Lung Cancer: Therapeutical Implications

    Directory of Open Access Journals (Sweden)

    A. Quintanal-Villalonga

    2016-01-01

    Full Text Available Lung cancer is a heterogeneous disease responsible for the most cases of cancer-related deaths. The majority of patients are clinically diagnosed at advanced stages, with a poor survival rate. For this reason, the identification of oncodrivers and novel biomarkers is decisive for the future clinical management of this pathology. The rise of high throughput technologies popularly referred to as “omics” has accelerated the discovery of new biomarkers and drivers for this pathology. Within them, tyrosine kinase receptors (TKRs have proven to be of importance as diagnostic, prognostic, and predictive tools and, due to their molecular nature, as therapeutic targets. Along this review, the role of TKRs in the different lung cancer histologies, research on improvement of anti-TKR therapy, and the current approaches to manage anti-TKR resistance will be discussed.

  20. Regulatory Phosphorylation of Ikaros by Bruton's Tyrosine Kinase

    Science.gov (United States)

    Zhang, Jian; Ishkhanian, Rita; Uckun, Fatih M.

    2013-01-01

    Diminished Ikaros function has been implicated in the pathogenesis of acute lymphoblastic leukemia (ALL), the most common form of childhood cancer. Therefore, a stringent regulation of Ikaros is of paramount importance for normal lymphocyte ontogeny. Here we provide genetic and biochemical evidence for a previously unknown function of Bruton's tyrosine kinase (BTK) as a partner and posttranslational regulator of Ikaros, a zinc finger-containing DNA-binding protein that plays a pivotal role in immune homeostasis. We demonstrate that BTK phosphorylates Ikaros at unique phosphorylation sites S214 and S215 in the close vicinity of its zinc finger 4 (ZF4) within the DNA binding domain, thereby augmenting its nuclear localization and sequence-specific DNA binding activity. Our results further demonstrate that BTK-induced activating phosphorylation is critical for the optimal transcription factor function of Ikaros. PMID:23977012

  1. Eosinophilic gastroenteritis in a patient with Bruton's tyrosine kinase deficiency.

    Science.gov (United States)

    Yamazaki, Susumu; Ohtsuka, Yoshikazu; Yokokura, Tomoaki; Yokota, Rena; Honjo, Asuka; Inage, Eisuke; Baba, Yosuke; Mori, Mari; Suzuki, Ryuyo; Iwata, Tsutomu; Shimizu, Toshiaki

    2016-05-01

    Eosinophilic gastrointestinal diseases (EGID) are relatively rare diseases characterized by eosinophilic infiltration of the gastrointestinal tract resulting in various gastrointestinal symptoms. EGID are often caused by allergic reactions or systemic eosinophilic disorders, but their comorbidity with Bruton's tyrosine kinase (BTK) deficiency has not been previously documented. Here, we report a case of eosinophilic gastroenteritis (EG) in a patient with BTK deficiency. Despite adequate replacement immunoglobulin (Ig) therapy, trough serum IgG was not maintained. To identify the underlying cause of the low trough level and chronic diarrhea, the intestine was investigated on endoscopy. We also screened for the variable number of tandem repeat polymorphism in FCGRT. Genetic analysis could not explain the low trough IgG, but endoscopy indicated eosinophilic enterocolitis. EG may be an important differential diagnosis when primary immunodeficiency patients have chronic diarrhea or continued low serum IgG. © 2016 Japan Pediatric Society.

  2. Regulatory phosphorylation of Ikaros by Bruton's tyrosine kinase.

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    Hong Ma

    Full Text Available Diminished Ikaros function has been implicated in the pathogenesis of acute lymphoblastic leukemia (ALL, the most common form of childhood cancer. Therefore, a stringent regulation of Ikaros is of paramount importance for normal lymphocyte ontogeny. Here we provide genetic and biochemical evidence for a previously unknown function of Bruton's tyrosine kinase (BTK as a partner and posttranslational regulator of Ikaros, a zinc finger-containing DNA-binding protein that plays a pivotal role in immune homeostasis. We demonstrate that BTK phosphorylates Ikaros at unique phosphorylation sites S214 and S215 in the close vicinity of its zinc finger 4 (ZF4 within the DNA binding domain, thereby augmenting its nuclear localization and sequence-specific DNA binding activity. Our results further demonstrate that BTK-induced activating phosphorylation is critical for the optimal transcription factor function of Ikaros.

  3. Tyrosine kinase inhibitors induced immune thrombocytopenia in chronic myeloid leukemia?

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    Avital F. Barak

    2011-12-01

    Full Text Available The outcome and quality of life of chronic myeloid leukemia (CML patients has remarkably changed with the treatment of tyrosine kinase inhibitors (TKIs. Currently, hematopoietic stem cell transplantation (HSCT is considered mainly as a third line salvage therapy in cases of TKIs resistance or intolerance. Here we describe a patient with chronic phase CML who developed both resistance and late occurrence of s severe thrombocytopenia on first and second generation TKIs and eventually underwent HSCT. Although the mechanism of the myelosuppression is not fully understood, we showed for the first time the development of dose dependent platelet antibodies in the presence of TKIs, suggesting the possibility of TKIs induced thrombocytopenia. Our case emphasizes that late development of severe myelosuppression during imatinib treatment is probably an important indication for consideration of early HSCT.

  4. SHP1 tyrosine phosphatase negatively regulates NPM-ALK tyrosine kinase signaling.

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    Honorat, Jean-François; Ragab, Ashraf; Lamant, Laurence; Delsol, Georges; Ragab-Thomas, Jeannie

    2006-05-15

    Anaplastic large-cell lymphoma (ALCL) is frequently associated with the 2;5 translocation and expresses the NPM-ALK fusion protein, which possesses a constitutive tyrosine kinase activity. We analyzed SHP1 tyrosine phosphatase expression and activity in 3 ALK-positive ALCL cell lines (Karpas 299, Cost, and SU-DHL1) and in lymph node biopsies (n = 40). We found an inverse correlation between the level of NPM-ALK phosphorylation and SHP1 phosphatase activity. Pull-down and coimmunoprecipitation experiments demonstrated a SHP1/NPM-ALK association. Furthermore, confocal microscopy performed on ALCL cell lines and biopsy specimens showed the colocalization of the 2 proteins in cytoplasmic bodies containing Y664-phosphorylated NPM-ALK. Dephosphorylation of NPM-ALK by SHP1 demonstrated that NPM-ALK was a SHP1 substrate. Downregulation of SHP1 expression by RNAi in Karpas cells led to hyperphosphorylation of NPM-ALK, STAT3 activation, and increase in cell proliferation. Furthermore, SHP1 overexpression in 3T3 fibroblasts stably expressing NPM-ALK led to the decrease of NPM-ALK phosphorylation, lower cell proliferation, and tumor progression in nude mice. These findings show that SHP1 is a negative regulator of NPM-ALK signaling. The use of tissue microarrays revealed that 50% of ALK-positive ALCLs were positive for SHP1. Our results suggest that SHP1 could be a critical enzyme in ALCL biology and a potential therapeutic target.

  5. Mapping of p140Cap phosphorylation sites: the EPLYA and EGLYA motifs have a key role in tyrosine phosphorylation and Csk binding, and are substrates of the Abl kinase.

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    Daniele Repetto

    Full Text Available Protein phosphorylation tightly regulates specific binding of effector proteins that control many diverse biological functions of cells (e. g. signaling, migration and proliferation. p140Cap is an adaptor protein, specifically expressed in brain, testis and epithelial cells, that undergoes phosphorylation and tunes its interactions with other regulatory molecules via post-translation modification. In this work, using mass spectrometry, we found that p140Cap is in vivo phosphorylated on tyrosine (Y within the peptide GEGLpYADPYGLLHEGR (from now on referred to as EGLYA as well as on three serine residues. Consistently, EGLYA has the highest score of in silico prediction of p140Cap phosphorylation. To further investigate the p140Cap function, we performed site specific mutagenesis on tyrosines inserted in EGLYA and EPLYA, a second sequence with the same highest score of phosphorylation. The mutant protein, in which both EPLYA/EGLYA tyrosines were converted to phenylalanine, was no longer tyrosine phosphorylated, despite the presence of other tyrosine residues in p140Cap sequence. Moreover, this mutant lost its ability to bind the C-terminal Src kinase (Csk, previously shown to interact with p140Cap by Far Western analysis. In addition, we found that in vitro and in HEK-293 cells, the Abelson kinase is the major kinase involved in p140Cap tyrosine phosphorylation on the EPLYA and EGLYA sequences. Overall, these data represent an original attempt to in vivo characterise phosphorylated residues of p140Cap. Elucidating the function of p140Cap will provide novel insights into its biological activity not only in normal cells, but also in tumors.

  6. Mapping of p140Cap phosphorylation sites: the EPLYA and EGLYA motifs have a key role in tyrosine phosphorylation and Csk binding, and are substrates of the Abl kinase.

    Science.gov (United States)

    Repetto, Daniele; Aramu, Simona; Boeri Erba, Elisabetta; Sharma, Nanaocha; Grasso, Silvia; Russo, Isabella; Jensen, Ole N; Cabodi, Sara; Turco, Emilia; Di Stefano, Paola; Defilippi, Paola

    2013-01-01

    Protein phosphorylation tightly regulates specific binding of effector proteins that control many diverse biological functions of cells (e. g. signaling, migration and proliferation). p140Cap is an adaptor protein, specifically expressed in brain, testis and epithelial cells, that undergoes phosphorylation and tunes its interactions with other regulatory molecules via post-translation modification. In this work, using mass spectrometry, we found that p140Cap is in vivo phosphorylated on tyrosine (Y) within the peptide GEGLpYADPYGLLHEGR (from now on referred to as EGLYA) as well as on three serine residues. Consistently, EGLYA has the highest score of in silico prediction of p140Cap phosphorylation. To further investigate the p140Cap function, we performed site specific mutagenesis on tyrosines inserted in EGLYA and EPLYA, a second sequence with the same highest score of phosphorylation. The mutant protein, in which both EPLYA/EGLYA tyrosines were converted to phenylalanine, was no longer tyrosine phosphorylated, despite the presence of other tyrosine residues in p140Cap sequence. Moreover, this mutant lost its ability to bind the C-terminal Src kinase (Csk), previously shown to interact with p140Cap by Far Western analysis. In addition, we found that in vitro and in HEK-293 cells, the Abelson kinase is the major kinase involved in p140Cap tyrosine phosphorylation on the EPLYA and EGLYA sequences. Overall, these data represent an original attempt to in vivo characterise phosphorylated residues of p140Cap. Elucidating the function of p140Cap will provide novel insights into its biological activity not only in normal cells, but also in tumors.

  7. Mechanisms of acquired resistance to tyrosine kinase inhibitors

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    Yi-fan Chen

    2011-12-01

    Full Text Available In recent years, structural and functional studies reveal that tyrosine kinases (TKs act as the essential components of signal transduction pathways that regulate cancer cell proliferation, apoptosis and angiogenesis, and therefore become potential targets for anticancer therapy. Most of TK inhibitors (TKIs are small molecular and hydrophobic compounds, thus they can rapidly reach their specific intracellular targets and inhibit the activation of the related TKs. Unfortunately, accompanied with patients who gain great benefit of TKIs therapy, increasing evidences of acquired resistance to these agents have been documented. The unveiling point mutations within the kinase domain, gene amplification or overexpression, or modification of signaling pathway have been implicated in drug resistance. Additionally, overexpression of ABC transporters is likely to set stage for resistant development. In this review, we focus on the discussion of the molecular mechanisms of acquired resistance to TKIs therapy. The mechanistic understanding may help to put forward new hypotheses on drug development and design better therapies to overcome TKIs resistance.

  8. 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.

  9. The Bmx tyrosine kinase induces activation of the Stat signaling pathway, which is specifically inhibited by protein kinase Cdelta.

    Science.gov (United States)

    Saharinen, P; Ekman, N; Sarvas, K; Parker, P; Alitalo, K; Silvennoinen, O

    1997-12-01

    Members of the hematopoietically expressed Tec tyrosine kinase family have an important role in hematopoietic signal transduction, as exemplified by the crucial role of Btk for B-cell differentiation and activation. Although a variety of cell surface receptors have been found to activate Tec tyrosine kinases, the specific signaling pathways and substrate molecules used by Tec kinases are still largely unknown. In this study a Tec family kinase, Bmx, was found to induce activation of the Stat signaling pathway. Bmx induced the tyrosine phosphorylation and DNA binding activity of all the Stat factors tested, including Stat1, Stat3, and Stat5, both in mammalian and insect cells. Bmx also induced transcriptional activation of Stat1- and Stat5-dependent reporter genes. Other cytoplasmic tyrosine kinases, Syk, Fyn, and c-Src, showed no or only weak ability to activate Stat proteins. Expression of Bmx in mammalian cells was found to induce activation of endogenous Stat proteins without activation of endogenous Jak kinases. We further analyzed the Bmx-mediated activation of Stat1, which was found to be regulated by protein kinase C delta (PKCdelta) isoform, but not beta 1, epsilon, or zeta isoforms, leading to inhibition of Stat1 tyrosine phosphorylation. In conclusion, these studies show that Bmx, a Tec family kinase, can function as an activator of the Stat signaling pathway and identify a role for PKCdelta in the regulation of Bmx signaling.

  10. Differential evolutionary wiring of the tyrosine kinase Btk.

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    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

  11. Identification of a fungi-specific lineage of protein kinases closely related to tyrosine kinases.

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    Zhongtao Zhao

    Full Text Available Tyrosine kinases (TKs specifically catalyze the phosphorylation of tyrosine residues in proteins and play essential roles in many cellular processes. Although TKs mainly exist in animals, recent studies revealed that some organisms outside the Opisthokont clade also contain TKs. The fungi, as the sister group to animals, are thought to lack TKs. To better understand the origin and evolution of TKs, it is important to investigate if fungi have TK or TK-related genes. We therefore systematically identified possible TKs across the fungal kingdom by using the profile hidden Markov Models searches and phylogenetic analyses. Our results confirmed that fungi lack the orthologs of animal TKs. We identified a fungi-specific lineage of protein kinases (FslK that appears to be a sister group closely related to TKs. Sequence analysis revealed that members of the FslK clade contain all the conserved protein kinase sub-domains and thus are likely enzymatically active. However, they lack key amino acid residues that determine TK-specific activities, indicating that they are not true TKs. Phylogenetic analysis indicated that the last common ancestor of fungi may have possessed numerous members of FslK. The ancestral FslK genes were lost in Ascomycota and Ustilaginomycotina and Pucciniomycotina of Basidiomycota during evolution. Most of these ancestral genes, however, were retained and expanded in Agaricomycetes. The discovery of the fungi-specific lineage of protein kinases closely related to TKs helps shed light on the origin and evolution of TKs and also has potential implications for the importance of these kinases in mushroom fungi.

  12. Identification of a fungi-specific lineage of protein kinases closely related to tyrosine kinases.

    Science.gov (United States)

    Zhao, Zhongtao; Jin, Qiaojun; Xu, Jin-Rong; Liu, Huiquan

    2014-01-01

    Tyrosine kinases (TKs) specifically catalyze the phosphorylation of tyrosine residues in proteins and play essential roles in many cellular processes. Although TKs mainly exist in animals, recent studies revealed that some organisms outside the Opisthokont clade also contain TKs. The fungi, as the sister group to animals, are thought to lack TKs. To better understand the origin and evolution of TKs, it is important to investigate if fungi have TK or TK-related genes. We therefore systematically identified possible TKs across the fungal kingdom by using the profile hidden Markov Models searches and phylogenetic analyses. Our results confirmed that fungi lack the orthologs of animal TKs. We identified a fungi-specific lineage of protein kinases (FslK) that appears to be a sister group closely related to TKs. Sequence analysis revealed that members of the FslK clade contain all the conserved protein kinase sub-domains and thus are likely enzymatically active. However, they lack key amino acid residues that determine TK-specific activities, indicating that they are not true TKs. Phylogenetic analysis indicated that the last common ancestor of fungi may have possessed numerous members of FslK. The ancestral FslK genes were lost in Ascomycota and Ustilaginomycotina and Pucciniomycotina of Basidiomycota during evolution. Most of these ancestral genes, however, were retained and expanded in Agaricomycetes. The discovery of the fungi-specific lineage of protein kinases closely related to TKs helps shed light on the origin and evolution of TKs and also has potential implications for the importance of these kinases in mushroom fungi.

  13. Cross-phosphorylation of bacterial serine/threonine and tyrosine protein kinases on key regulatory residues

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    Lei eShi

    2014-09-01

    Full Text Available Bacteria possess protein serine/threonine and tyrosine kinases which resemble eukaryal kinases in their capacity to phosphorylate multiple substrates. We hypothesized that the analogy might extend further, and bacterial kinases may also undergo mutual phosphorylation and activation, which is currently considered as a hallmark of eukaryal kinase networks. In order to test this hypothesis, we explored the capacity of all members of four different classes of serine/threonine and tyrosine kinases present in the firmicute model organism Bacillus subtilis to phosphorylate each other in vitro and interact with each other in vivo. The interactomics data suggested a high degree of connectivity among all types of kinases, while phosphorylation assays revealed equally wide-spread cross-phosphorylation events. Our findings suggest that the Hanks-type kinases PrkC, PrkD and YabT exhibit the highest capacity to phosphorylate other B. subtilis kinases, while the BY-kinase PtkA and the two-component-like kinases RsbW and SpoIIAB show the highest propensity to be phosphorylated by other kinases. Analysis of phosphorylated residues on several selected recipient kinases suggests that most cross-phosphorylation events concern key regulatory residues. Therefore, cross-phosphorylation events are very likely to influence the capacity of recipient kinases to phosphorylate substrates downstream in the signal transduction cascade. We therefore conclude that bacterial serine/threonine and tyrosine kinases probably engage in a network-type behavior previously described only in eukaryal cells.

  14. A novel putative tyrosine kinase receptor with oncogenic potential.

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    Janssen, J W; Schulz, A S; Steenvoorden, A C; Schmidberger, M; Strehl, S; Ambros, P F; Bartram, C R

    1991-11-01

    We have detected transforming activity by a tumorigenicity assay using NIH3T3 cells transfected with DNA from a chronic myeloproliferative disorder patient. Here, we report the cDNA cloning of the corresponding oncogene, designated UFO, in allusion to the as yet unidentified function of its protein. Nucleotide sequence analysis of a 3116bp cDNA clone revealed a 2682-bp-long open reading frame capable of directing the synthesis of a 894 amino acid polypeptide. The predicted UFO protein exhibits characteristic features of a transmembrane receptor with associated tyrosine kinase activity. The UFO proto-oncogene maps to human chromosome 19q13.1 and is transcribed into two 5.0 kb and 3.2 kb mRNAs in human bone marrow and human tumor cell lines. The UFO locus is evolutionarily conserved between vertebrate species. A 4.0 kb mRNA of the murine UFO homolog is expressed in a variety of different mouse tissues. We thus have identified a novel element of the complex signaling network involved in the control of cell proliferation and differentiation.

  15. Mutations in Bruton's tyrosine kinase impair IgA responses.

    Science.gov (United States)

    Mitsuiki, Noriko; Yang, Xi; Bartol, Sophinus J W; Grosserichter-Wagener, Christina; Kosaka, Yoshiyuki; Takada, Hidetoshi; Imai, Kohsuke; Kanegane, Hirokazu; Mizutani, Shuki; van der Burg, Mirjam; van Zelm, Menno C; Ohara, Osamu; Morio, Tomohiro

    2015-03-01

    X-linked agammaglobulinemia (XLA) is a primary immunodeficiency caused by mutations in Bruton's tyrosine kinase (BTK), and is characterized by markedly decreased numbers of blood B cells and an absence of all immunoglobulin isotypes. We performed whole exome sequencing in a male pediatric patient with dysgammaglobulinemia with IgA deficiency. Genetic analysis revealed a BTK missense mutation (Thr316Ala). To investigate whether a BTK mutation underlay this antibody deficiency with marked decrease of IgA in this patient, we performed functional analyses of B cells and phagocytes, and molecular analyses of somatic hypermutation and class switch recombination. The BTK missense mutation resulted in B cells with reduced BTK and high IgM expression. Equal proportions of CD19(low) and CD19(normal) fractions were observed, and both included naïve and memory B cells. Calcium influx and phospholipase Cγ2 phosphorylation upon IgM stimulation were marginally impaired in CD19(low), but not in CD19(+) B cells. Similar to XLA patients, IgA transcripts showed low SHM levels, whereas IgG transcripts were hardly affected. Our analyses suggest that the BTK mutation likely underlies the disease in this case, and that hypomorphic BTK mutations can result in normal circulating B cell numbers, but specifically impair IgA responses.

  16. Bruton's tyrosine kinase inhibitors in chronic lymphocytic leukemia and lymphoma.

    Science.gov (United States)

    Varma, Gaurav; Johnson, Tyler P; Advani, Ranjana H

    2016-07-01

    The development of Bruton's tyrosine kinase (BTK) inhibitors and their introduction into clinical practice represent a major advance in the treatment of chronic lymphocytic leukemia (CLL) and other B-cell lymphomas. Although ibrutinib is the only BTK inhibitor that has been approved by the US Food and Drug Administration, several others are under investigation. Ibrutinib is currently approved for use in relapsed/refractory CLL, CLL with 17p deletion (del[17p]), relapsed or refractory mantle cell lymphoma, and Waldenström macroglobulinemia. Although it is clear that ibrutinib has altered treatment paradigms and outcomes in these diseases, several questions remain regarding (1) its role in frontline vs salvage therapy; (2) its use as a single agent vs in combination with biologic agents, other small molecules, or traditional chemoimmunotherapy; (3) the optimal duration of treatment; and (4) the treatment of patients who cannot tolerate or have disease resistant to ibrutinib. Because sparse clinical data are available on other BTK inhibitors, it is unclear at present whether their clinical efficacy and toxicity will differ from those of ibrutinib.

  17. Role of Receptor Tyrosine Kinases and Their Ligands in Glioblastoma

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    Estefanía Carrasco-García

    2014-04-01

    Full Text Available Glioblastoma multiforme is the most frequent, aggressive and fatal type of brain tumor. Glioblastomas are characterized by their infiltrating nature, high proliferation rate and resistance to chemotherapy and radiation. Recently, oncologic therapy experienced a rapid evolution towards “targeted therapy,” which is the employment of drugs directed against particular targets that play essential roles in proliferation, survival and invasiveness of cancer cells. A number of molecules involved in signal transduction pathways are used as molecular targets for the treatment of various tumors. In fact, inhibitors of these molecules have already entered the clinic or are undergoing clinical trials. Cellular receptors are clear examples of such targets and in the case of glioblastoma multiforme, some of these receptors and their ligands have become relevant. In this review, the importance of glioblastoma multiforme in signaling pathways initiated by extracellular tyrosine kinase receptors such as EGFR, PDGFR and IGF-1R will be discussed. We will describe their ligands, family members, structure, activation mechanism, downstream molecules, as well as the interaction among these pathways. Lastly, we will provide an up-to-date review of the current targeted therapies in cancer, in particular glioblastoma that employ inhibitors of these pathways and their benefits.

  18. Receptor tyrosine kinases as target for anti-cancer therapy.

    Science.gov (United States)

    Brunelleschi, S; Penengo, L; Santoro, M M; Gaudino, G

    2002-01-01

    Receptor tyrosine kinases (RTKs) are cell surface transmembrane proteins responsible for intracellular signal transduction. They are expressed in several cell types and, after activation by growth factor binding, trigger a series of intracellular pathways, leading to a wide variety of cell responses (e.g., differentiation, proliferation, migration and invasion, angiogenesis, survival). Over-expression and/or structural alteration of RTKs family members are often associated to human cancers and tumor cells are known to use RTK transduction pathways to achieve tumor growth, angiogenesis and metastasis. Therefore, RTKs represent pivotal target in approaches of cancer therapy. A number of small molecules acting as RTK inhibitors have been synthesized by pharmaceutical companies and are under clinical trials, are being analyzed in animal models or have been successfully marketed. Ligand-dependent downregulation of RTKs is a critical step for modulating their activity and the adaptor Cbl has been indicated as the key protein involved in negative regulation of RTKs, such as EGF and HGF receptors. These data suggest novel potential pharmacological targets for the treatment of human malignancies associated to oncogenic activation of RTKs.

  19. Tyrosine inhibits creatine kinase activity in cerebral cortex of young rats.

    Science.gov (United States)

    de Andrade, Rodrigo Binkowski; Gemelli, Tanise; Rojas, Denise Bertin; Funchal, Cláudia; Dutra-Filho, Carlos Severo; Wannmacher, Clovis Milton Duval

    2011-09-01

    Tyrosine accumulates in inborn errors of tyrosine catabolism, especially in tyrosinemia type II, where tyrosine levels are highly elevated in tissues and physiological fluids of affected patients. Tyrosinemia type II is a disorder of autosomal recessive inheritance characterized by neurological symptoms similar to those observed in patients with creatine deficiency syndromes. Considering that the mechanisms of brain damage in these disorders are poorly known, in the present study our main objective was to investigate the in vivo and in vitro effects of different concentrations and preincubation times of tyrosine on cytosolic and mitochondrial creatine kinase activities of the cerebral cortex from 14-day-old Wistar rats. The cytosolic CK was reduced by 15% at 1 mM and 32% at 2 mM tyrosine. Similarly, the mitochondrial CK was inhibited by 15% at 1 mM and 22% at 2 mM tyrosine. We observed that the inhibition caused by tyrosine was concentration-dependent and was prevented by reduced glutathione. Results also indicated that mitochondrial, but not cytosolic creatine kinase activity was inhibited by tyrosine in a time-dependent way. Finally, a single injection of L-Tyrosine methyl ester administered i.p. decreased cytosolic (31%) and mitochondrial (18%) creatine kinase activities of brain cortex from rats. Considering that creatine kinase is an enzyme dependent of thiol residues for its function and tyrosine induces oxidative stress, the results suggest that the inhibition caused by tyrosine might occur by oxidation of essential sulfhydryl groups of the enzyme. In case this also occurs in patients with tyrosinemia, it is possible that creatine kinase inhibition may contribute to the neurological dysfunction characteristic of tyrosinemia.

  20. Functional Crosstalk Between WNT Signaling and Tyrosine Kinase Signaling in Cancer.

    Science.gov (United States)

    Anastas, Jaimie N

    2015-12-01

    Extensive molecular characterization of tumors has revealed that the activity of multiple signaling pathways is often simultaneously dampened or enhanced in cancer cells. Aberrant WNT signaling and tyrosine kinase signaling are two pathways that are frequently up- or downregulated in cancer. Although signaling pathways regulated by WNTs, tyrosine kinases, and other factors are often conceptualized as independent entities, the biological reality is likely much more complex. Understanding the mechanisms of crosstalk between multiple signal transduction networks is a key challenge for cancer researchers. The overall goals of this review are to describe mechanisms of crosstalk between WNT and tyrosine kinase pathways in cancer and to discuss how understanding intersections between WNT and tyrosine kinase signaling networks might be exploited to improve current therapies.

  1. Afatinib: emerging next-generation tyrosine kinase inhibitor for NSCLC

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    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

  2. Mefloquine neurotoxicity is mediated by non-receptor tyrosine kinase.

    Science.gov (United States)

    Milatovic, Dejan; Jenkins, Jerry W; Hood, Jonathan E; Yu, Yingchun; Rongzhu, Lu; Aschner, Michael

    2011-10-01

    Among several available antimalarial drugs, mefloquine has proven to be effective against drug-resistant Plasmodium falciparum and remains the drug of choice for both therapy and chemoprophylaxis. However, mefloquine is known to cause adverse neurological and/or psychiatric symptoms, which offset its therapeutic advantage. The exact mechanisms leading to the adverse neurological effects of mefloquine are poorly defined. Alterations in neurotransmitter release and calcium homeostasis, the inhibition of cholinesterases and the interaction with adenosine A(2A) receptors have been hypothesized to play prominent roles in mediating the deleterious effects of this drug. Our recent data have established that mefloquine can also trigger oxidative damage and subsequent neurodegeneration in rat cortical primary neurons. Furthermore, we have utilized a system biology-centered approach and have constructed a pathway model of cellular responses to mefloquine, identifying non-receptor tyrosine kinase 2 (Pyk2) as a critical target in mediating mefloquine neurotoxicity. In this study, we sought to establish an experimental validation of Pyk2 using gene-silencing techniques (siRNA). We have examined whether the downregulation of Pyk2 in primary rat cortical neurons alters mefloquine neurotoxicity by evaluating cell viability, apoptosis and oxidative stress. Results from our study have confirmed that mefloquine neurotoxicity is associated with apoptotic response and oxidative injury, and we have demonstrated that mefloquine affects primary rat cortical neurons, at least in part, via Pyk2. The implication of these findings may prove beneficial in suppressing the neurological side effects of mefloquine and developing effective therapeutic modalities to offset its adverse effects.

  3. Structural basis for the regulation mechanism of the tyrosine kinase CapB from Staphylococcus aureus.

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    Vanesa Olivares-Illana

    2008-06-01

    Full Text Available Bacteria were thought to be devoid of tyrosine-phosphorylating enzymes. However, several tyrosine kinases without similarity to their eukaryotic counterparts have recently been identified in bacteria. They are involved in many physiological processes, but their accurate functions remain poorly understood due to slow progress in their structural characterization. They have been best characterized as copolymerases involved in the synthesis and export of extracellular polysaccharides. These compounds play critical roles in the virulence of pathogenic bacteria, and bacterial tyrosine kinases can thus be considered as potential therapeutic targets. Here, we present the crystal structures of the phosphorylated and unphosphorylated states of the tyrosine kinase CapB from the human pathogen Staphylococcus aureus together with the activator domain of its cognate transmembrane modulator CapA. This first high-resolution structure of a bacterial tyrosine kinase reveals a 230-kDa ring-shaped octamer that dissociates upon intermolecular autophosphorylation. These observations provide a molecular basis for the regulation mechanism of the bacterial tyrosine kinases and give insights into their copolymerase function.

  4. Identification of c-Src tyrosine kinase substrates using mass spectrometry and peptide microarrays

    DEFF Research Database (Denmark)

    Amanchy, Ramars; Zhong, Jun; Molina, Henrik;

    2008-01-01

    c-Src tyrosine kinase plays a critical role in signal transduction downstream of growth factor receptors, integrins and G protein-coupled receptors. We used stable isotope labeling with amino acids in cell culture (SILAC) approach to identify additional substrates of c-Src tyrosine kinase in human...... embryonic kidney 293T cells. We have identified 10 known substrates and interactors of c-Src and Src family kinases along with 26 novel substrates. We have experimentally validated 4 of the novel proteins (NICE-4, RNA binding motif 10, FUSE-binding protein 1 and TRK-fused gene) as direct substrates of c......-Src using in vitro kinase assays and cotransfection experiments. Significantly, using a c-Src specific inhibitor, we were also able to implicate 3 novel substrates (RNA binding motif 10, EWS1 and Bcl-2 associated transcription factor) in PDGF signaling. Finally, to identify the exact tyrosine residues...

  5. Protein-tyrosine Phosphatase and Kinase Specificity in Regulation of SRC and Breast Tumor Kinase* ♦

    Science.gov (United States)

    Fan, Gaofeng; Aleem, Saadat; Yang, Ming; Miller, W. Todd; Tonks, Nicholas K.

    2015-01-01

    Despite significant evidence to the contrary, the view that phosphatases are “nonspecific” still pervades the field. Systems biology approaches to defining how signal transduction pathways are integrated at the level of whole organisms also often downplay the contribution of phosphatases, defining them as “erasers” that serve merely to restore the system to its basal state. Here, we present a study that counteracts the idea of “nonspecific phosphatases.” We have characterized two structurally similar and functionally related kinases, BRK and SRC, which are regulated by combinations of activating autophosphorylation and inhibitory C-terminal sites of tyrosine phosphorylation. We demonstrated specificity at the level of the kinases in that SRMS phosphorylated the C terminus of BRK, but not SRC; in contrast, CSK is the kinase responsible for C-terminal phosphorylation of SRC, but not BRK. For the phosphatases, we observed that RNAi-mediated suppression of PTP1B resulted in opposing effects on the activity of BRK and SRC and have defined the mechanisms underlying this specificity. PTP1B inhibited BRK by directly dephosphorylating the Tyr-342 autophosphorylation site. In contrast, PTP1B potentiated SRC activity, but not by dephosphorylating SRC itself directly; instead, PTP1B regulated the interaction between CBP/PAG and CSK. SRC associated with, and phosphorylated, the transmembrane protein CBP/PAG at Tyr-317, resulting in CSK recruitment. We identified PAG as a substrate of PTP1B, and dephosphorylation abolished recruitment of the inhibitory kinase CSK. Overall, these findings illustrate how the combinatorial effects of PTKs and PTPs may be integrated to regulate signaling, with both classes of enzymes displaying exquisite specificity. PMID:25897081

  6. Protein-tyrosine Phosphatase and Kinase Specificity in Regulation of SRC and Breast Tumor Kinase.

    Science.gov (United States)

    Fan, Gaofeng; Aleem, Saadat; Yang, Ming; Miller, W Todd; Tonks, Nicholas K

    2015-06-26

    Despite significant evidence to the contrary, the view that phosphatases are "nonspecific" still pervades the field. Systems biology approaches to defining how signal transduction pathways are integrated at the level of whole organisms also often downplay the contribution of phosphatases, defining them as "erasers" that serve merely to restore the system to its basal state. Here, we present a study that counteracts the idea of "nonspecific phosphatases." We have characterized two structurally similar and functionally related kinases, BRK and SRC, which are regulated by combinations of activating autophosphorylation and inhibitory C-terminal sites of tyrosine phosphorylation. We demonstrated specificity at the level of the kinases in that SRMS phosphorylated the C terminus of BRK, but not SRC; in contrast, CSK is the kinase responsible for C-terminal phosphorylation of SRC, but not BRK. For the phosphatases, we observed that RNAi-mediated suppression of PTP1B resulted in opposing effects on the activity of BRK and SRC and have defined the mechanisms underlying this specificity. PTP1B inhibited BRK by directly dephosphorylating the Tyr-342 autophosphorylation site. In contrast, PTP1B potentiated SRC activity, but not by dephosphorylating SRC itself directly; instead, PTP1B regulated the interaction between CBP/PAG and CSK. SRC associated with, and phosphorylated, the transmembrane protein CBP/PAG at Tyr-317, resulting in CSK recruitment. We identified PAG as a substrate of PTP1B, and dephosphorylation abolished recruitment of the inhibitory kinase CSK. Overall, these findings illustrate how the combinatorial effects of PTKs and PTPs may be integrated to regulate signaling, with both classes of enzymes displaying exquisite specificity. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Contribution of casein kinase 2 and spleen tyrosine kinase to CFTR trafficking and protein kinase A-induced activity.

    Science.gov (United States)

    Luz, Simão; Kongsuphol, Patthara; Mendes, Ana Isabel; Romeiras, Francisco; Sousa, Marisa; Schreiber, Rainer; Matos, Paulo; Jordan, Peter; Mehta, Anil; Amaral, Margarida D; Kunzelmann, Karl; Farinha, Carlos M

    2011-11-01

    Previously, the pleiotropic "master kinase" casein kinase 2 (CK2) was shown to interact with CFTR, the protein responsible for cystic fibrosis (CF). Moreover, CK2 inhibition abolished CFTR conductance in cell-attached membrane patches, native epithelial ducts, and Xenopus oocytes. CFTR possesses two CK2 phosphorylation sites (S422 and T1471), with unclear impact on its processing and trafficking. Here, we investigated the effects of mutating these CK2 sites on CFTR abundance, maturation, and degradation coupled to effects on ion channel activity and surface expression. We report that CK2 inhibition significantly decreased processing of wild-type (wt) CFTR, with no effect on F508del CFTR. Eliminating phosphorylation at S422 and T1471 revealed antagonistic roles in CFTR trafficking: S422 activation versus T1471 inhibition, as evidenced by a severe trafficking defect for the T1471D mutant. Notably, mutation of Y512, a consensus sequence for the spleen tyrosine kinase (SYK) possibly acting in a CK2 context adjacent to the common CF-causing defect F508del, had a strong effect on both maturation and CFTR currents, allowing the identification of this kinase as a novel regulator of CFTR. These results reinforce the importance of CK2 and the S422 and T1471 residues for regulation of CFTR and uncover a novel regulation of CFTR by SYK, a recognized controller of inflammation.

  8. Enhancement of cytosolic tyrosine kinase activity by propylthiouracil-induced hyperplasia in the rat thyroid.

    Science.gov (United States)

    Polychronakos, C; Piscina, R; Fantus, I G

    1989-01-01

    Hyperplasia of the thyroid gland induced by propylthiouracil (PTU) is a well established model of rapid cell proliferation in vivo. Recent evidence indicates that tyrosine kinase activity is associated with growth factor receptors and oncogene protein products and may have an important regulatory action in the control of cell growth. Thus, we examined tyrosine kinase activity in rat thyroid membrane and cytosol preparations at rest and during PTU-induced hyperplasia. Although kinase activity was present in a crude microsomal membrane preparation, no change was observed during thyroid growth. In contrast, tyrosine kinase activity assayed with the artificial substrate poly(Glu,Na:Tyr) 4:1 was present in normal rat thyroid cytosol and increased 2- to 6-fold during the rapid phase of hyperplasia in the first 5-10 days of PTU treatment. It declined to control values by day 15, when the size and DNA content of the thyroid reached a plateau. Preincubation of the cytosolic preparations with several peptides known to bind to and activate growth factor receptor tyrosine kinases failed to enhance the activity, suggesting, along with the cytosolic localization, that the activity was distinct from these receptors. By gel filtration chromatography and polyacrylamide gel electrophoresis, tyrosine kinase activity was associated with a 55 kDa protein. Partial purification over a poly(Glu,Na:Tyr)4:1-Sepharose column, yielded a protein that appeared capable of autophosphorylation. It is suggested that this tyrosine kinase plays a role in mediating the growth-promoting effects of this model of thyroid cell hyperplasia.

  9. Design and synthesis of carbazole carboxamides as promising inhibitors of Bruton's tyrosine kinase (BTK) and Janus kinase 2 (JAK2).

    Science.gov (United States)

    Liu, Qingjie; Batt, Douglas G; Lippy, Jonathan S; Surti, Neha; Tebben, Andrew J; Muckelbauer, Jodi K; Chen, Lin; An, Yongmi; Chang, Chiehying; Pokross, Matt; Yang, Zheng; Wang, Haiqing; Burke, James R; Carter, Percy H; Tino, Joseph A

    2015-10-01

    Four series of disubstituted carbazole-1-carboxamides were designed and synthesised as inhibitors of Bruton's tyrosine kinase (BTK). 4,7- and 4,6-disubstituted carbazole-1-carboxamides were potent and selective inhibitors of BTK, while 3,7- and 3,6-disubstituted carbazole-1-carboxamides were potent and selective inhibitors of Janus kinase 2 (JAK2). Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Autoinhibition of Bruton's tyrosine kinase (Btk) and activation by soluble inositol hexakisphosphate.

    Science.gov (United States)

    Wang, Qi; Vogan, Erik M; Nocka, Laura M; Rosen, Connor E; Zorn, Julie A; Harrison, Stephen C; Kuriyan, John

    2015-02-20

    Bruton's tyrosine kinase (Btk), a Tec-family tyrosine kinase, is essential for B-cell function. We present crystallographic and biochemical analyses of Btk, which together reveal molecular details of its autoinhibition and activation. Autoinhibited Btk adopts a compact conformation like that of inactive c-Src and c-Abl. A lipid-binding PH-TH module, unique to Tec kinases, acts in conjunction with the SH2 and SH3 domains to stabilize the inactive conformation. In addition to the expected activation of Btk by membranes containing phosphatidylinositol triphosphate (PIP3), we found that inositol hexakisphosphate (IP6), a soluble signaling molecule found in both animal and plant cells, also activates Btk. This activation is a consequence of a transient PH-TH dimerization induced by IP6, which promotes transphosphorylation of the kinase domains. Sequence comparisons with other Tec-family kinases suggest that activation by IP6 is unique to Btk.

  11. Elucidation of a four-site allosteric network in fibroblast growth factor receptor tyrosine kinases

    Science.gov (United States)

    Chen, Huaibin; Marsiglia, William M; Cho, Min-Kyu; Huang, Zhifeng; Deng, Jingjing; Blais, Steven P; Gai, Weiming; Bhattacharya, Shibani; Neubert, Thomas A; Traaseth, Nathaniel J; Mohammadi, Moosa

    2017-01-01

    Receptor tyrosine kinase (RTK) signaling is tightly regulated by protein allostery within the intracellular tyrosine kinase domains. Yet the molecular determinants of allosteric connectivity in tyrosine kinase domain are incompletely understood. By means of structural (X-ray and NMR) and functional characterization of pathogenic gain-of-function mutations affecting the FGF receptor (FGFR) tyrosine kinase domain, we elucidated a long-distance allosteric network composed of four interconnected sites termed the ‘molecular brake’, ‘DFG latch’, ‘A-loop plug’, and ‘αC tether’. The first three sites repress the kinase from adopting an active conformation, whereas the αC tether promotes the active conformation. The skewed design of this four-site allosteric network imposes tight autoinhibition and accounts for the incomplete mimicry of the activated conformation by pathogenic mutations targeting a single site. Based on the structural similarity shared among RTKs, we propose that this allosteric model for FGFR kinases is applicable to other RTKs. DOI: http://dx.doi.org/10.7554/eLife.21137.001 PMID:28166054

  12. Lichen planopilaris-like eruption during treatment with tyrosine kinase inhibitor nilotinib*

    Science.gov (United States)

    Leitão, Juliana Ribeiro; Valente, Neusa Yuriko Sakai; Kakizaki, Priscila; Veronez, Isis Suga; Pires, Mario Cezar

    2016-01-01

    Tyrosine kinase inhibitors are effective as a target therapy for malignant neoplasms. Imatinib was the first tyrosine kinase inhibitor used. After its introduction, several other drugs have appeared with a similar mechanism of action, but less prone to causing resistance. Even though these drugs are selective, their toxicity does not exclusively target cancer cells, and skin toxicity is the most common non-hematologic adverse effect. We report an eruption similar to lichen planopilaris that developed during therapy with nilotinib, a second generation tyrosine kinase inhibitor, in a patient with chronic myeloid leukemia resistant to imatinib. In a literature review, we found only one report of non-scarring alopecia due to the use of nilotinib.

  13. Giant hub Src and Syk tyrosine kinase thermodynamic profiles recapitulate evolution

    Science.gov (United States)

    Phillips, J. C.

    2017-10-01

    Thermodynamic scaling theory, previously applied mainly to small proteins, here analyzes quantitative evolution of the titled functional network giant hub enzymes. The broad domain structure identified homologically is confirmed hydropathically using amino acid sequences only. The most surprising results concern the evolution of the tyrosine kinase globular surface roughness from avians to mammals, which is first order, compared to the evolution within mammals from rodents to humans, which is second order. The mystery of the unique amide terminal region of proto oncogene tyrosine protein kinase is resolved by the discovery there of a rare hydroneutral septad targeting cluster, which is paralleled by an equally rare octad catalytic cluster in tyrosine kinase in humans and a few other species (cat and dog). These results, which go far towards explaining why these proteins are among the largest giant hubs in protein interaction networks, use no adjustable parameters.

  14. Signal transduction pathway analysis in fibromatosis: receptor and nonreceptor tyrosine kinases.

    Science.gov (United States)

    Cates, Justin M M; Black, Jennifer O; Itani, Doha M; Fasig, John H; Keedy, Vicki L; Hande, Kenneth R; Whited, Brent W; Homlar, Kelly C; Halpern, Jennifer L; Holt, Ginger E; Schwartz, Herbert S; Coffin, Cheryl M

    2012-10-01

    Despite reports of receptor tyrosine kinase activation in desmoid-type fibromatosis, therapeutic benefits of kinase inhibitor therapy are unpredictable. Variability in signal transduction or cellular kinases heretofore unevaluated in desmoid tumors may be responsible for these inconsistent responses. In either case, a better understanding of growth regulatory signaling pathways is necessary to assess the theoretical potential of inhibitor therapy. Immunohistochemical analysis of tyrosine kinases and activated isoforms of downstream signal transduction proteins was performed on a tissue microarray containing 27 cases of desmoid-type fibromatosis and 14 samples of scar; 6 whole sections of normal fibrous tissue were studied for comparison. Platelet-derived growth factor receptor, β type, and focal adhesion kinase 1 were expressed in all desmoid tumors and healing scars but only 80% and 50% of nonproliferative fibrous tissue samples, respectively. Hepatocyte growth factor receptor was detected in 89% of desmoids and all scars tested, but not in any of the fibrous tissue samples. Epidermal growth factor receptor was detected in only 12% of desmoids and not in scar or fibrous tissue. Mast/stem cell growth factor receptor, receptor tyrosine-protein kinase erbB-2, and phosphorylated insulin-like growth factor 1 receptor/insulin receptor were negative in all study cases. Variable levels of phosphorylated downstream signal transduction molecules RAC-α/β/γ serine/threonine-protein kinase, mitogen-activated protein kinase, and signal transducer and activator of transcription-3 were observed in desmoids (58%, 62%, and 67%), scar tissues (100%, 86%, and 86%), and fibrous tissue (33%, 17%, and 17%). These results indicate that tyrosine kinase signaling is active in both fibromatosis and healing scar, but not in most nonproliferating fibrous tissues. Although platelet-derived growth factor receptor, β type, is expressed ubiquitously in desmoids, the kinases driving cell

  15. The Cbl Proto-Oncogene Product Negatively Regulates the Src-Family Tyrosine Kinase Fyn by Enhancing Its Degradation

    OpenAIRE

    2000-01-01

    Fyn is a prototype Src-family tyrosine kinase that plays specific roles in neural development, keratinocyte differentiation, and lymphocyte activation, as well as roles redundant with other Src-family kinases. Similar to other Src-family kinases, efficient regulation of Fyn is achieved through intramolecular binding of its SH3 and SH2 domains to conserved regulatory regions. We have investigated the possibility that the tyrosine kinase regulatory protein Cbl provides a complementary mechanism...

  16. Using ovality to predict nonmutagenic, orally efficacious pyridazine amides as cell specific spleen tyrosine kinase inhibitors.

    Science.gov (United States)

    Lucas, Matthew C; Bhagirath, Niala; Chiao, Eric; Goldstein, David M; Hermann, Johannes C; Hsu, Pei-Yuan; Kirchner, Stephan; Kennedy-Smith, Joshua J; Kuglstatter, Andreas; Lukacs, Christine; Menke, John; Niu, Linghao; Padilla, Fernando; Peng, Ying; Polonchuk, Liudmila; Railkar, Aruna; Slade, Michelle; Soth, Michael; Xu, Daigen; Yadava, Preeti; Yee, Calvin; Zhou, Mingyan; Liao, Cheng

    2014-03-27

    Inhibition of spleen tyrosine kinase has attracted much attention as a mechanism for the treatment of cancers and autoimmune diseases such as asthma, rheumatoid arthritis, and systemic lupus erythematous. We report the structure-guided optimization of pyridazine amide spleen tyrosine kinase inhibitors. Early representatives of this scaffold were highly potent and selective but mutagenic in an Ames assay. An approach that led to the successful identification of nonmutagenic examples, as well as further optimization to compounds with reduced cardiovascular liabilities is described. Select pharmacokinetic and in vivo efficacy data are presented.

  17. 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

    . The 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...

  18. Tyrosine Phosphorylation of Tau by the Src Family Kinases Lck and Fyn

    Directory of Open Access Journals (Sweden)

    Bird Ian N

    2011-01-01

    Full Text Available Abstract Background Tau protein is the principal component of the neurofibrillary tangles found in Alzheimer's disease, where it is hyperphosphorylated on serine and threonine residues, and recently phosphotyrosine has been demonstrated. The Src-family kinase Fyn has been linked circumstantially to the pathology of Alzheimer's disease, and shown to phosphorylate Tyr18. Recently another Src-family kinase, Lck, has been identified as a genetic risk factor for this disease. Results In this study we show that Lck is a tau kinase. In vitro, comparison of Lck and Fyn showed that while both kinases phosphorylated Tyr18 preferentially, Lck phosphorylated other tyrosines somewhat better than Fyn. In co-transfected COS-7 cells, mutating any one of the five tyrosines in tau to phenylalanine reduced the apparent level of tau tyrosine phosphorylation to 25-40% of that given by wild-type tau. Consistent with this, tau mutants with only one remaining tyrosine gave poor phosphorylation; however, Tyr18 was phosphorylated better than the others. Conclusions Fyn and Lck have subtle differences in their properties as tau kinases, and the phosphorylation of tau is one mechanism by which the genetic risk associated with Lck might be expressed pathogenically.

  19. Phosphoinositide 3-kinase regulates crosstalk between Trk A tyrosine kinase and p75(NTR)-dependent sphingolipid signaling pathways.

    Science.gov (United States)

    Bilderback, T R; Gazula, V R; Dobrowsky, R T

    2001-03-01

    The mechanism of crosstalk between signaling pathways coupled to the Trk A and p75(NTR) neurotrophin receptors in PC12 cells was examined. In response to nerve growth factor (NGF), Trk A activation inhibited p75(NTR)-dependent sphingomyelin (SM) hydrolysis. The phosphoinositide 3-kinase (PI 3-kinase) inhibitor, LY294002, reversed this inhibition suggesting that Trk A activation of PI 3-kinase is necessary to inhibit sphingolipid signaling by p75(NTR). In contrast, SM hydrolysis induced by neurotrophin-3 (NT-3), which did not activate PI-3 kinase, was uneffected by LY294002. However, transient expression of a constituitively active PI 3-kinase inhibited p75(NTR)-dependent SM hydrolysis by both NGF and NT-3. Intriguingly, NGF induced an association of activated PI 3-kinase with acid sphingomyelinase (SMase). This interaction localized to caveolae-related domains and correlated with a 50% decrease in immunoprecipitated acid SMase activity. NGF-stimulated PI 3-kinase activity was necessary for inhibition of acid SMase but was not required for ligand-induced association of the p85 subunit of PI 3-kinase with the phospholipase. Finally, this interaction was specific for NGF since EGF did not induce an association of PI 3-kinase with acid SMase. In summary, our data suggest that PI 3-kinase regulates the inhibitory crosstalk between Trk A tyrosine kinase and p75(NTR)-dependent sphingolipid signaling pathways and that this interaction localizes to caveolae-related domains.

  20. Effects of tyrosine kinase and phosphatase inhibitors on mitosis progression in synchronized tobacco BY-2 cells.

    Science.gov (United States)

    Sheremet, Ya A; Yemets, A I; Azmi, A; Vissenberg, K; Verbelen, J P; Blume, Ya B

    2012-01-01

    To test whether reversible tubulin phosphorylation plays any role in the process of plant mitosis the effects of inhibitors of tyrosine kinases, herbimycin A, genistein and tyrphostin AG 18, and of an inhibitor of tyrosine phosphatases, sodium orthovanadate, on microtubule organization and mitosis progression in a synchronized BY-2 culture has been investigated. It was found that treatment with inhibitors of tyrosine kinases of BY-2 cells at the G2/M transition did not lead to visible disturbances of mitotic microtubule structures, while it did reduce the frequency of their appearance. We assume that a decreased tyrosine phosphorylation level could alter the microtubule dynamic instability parameters during interphase/prophase transition. All types of tyrosine kinase inhibitors used caused a prophase delay: herbimycin A and genistein for 2 h, and tyrphostin AG18 for 1 h. Thereafter the peak of mitosis was displaced for 1 h by herbimycin A or genistein exposure, but after tyrphostin AG18 treatment the timing of the mitosis-peak was comparable to that in control cells. Enhancement of tyrosine phosphorylation induced by the tyrosine phosphatase inhibitor resulted in the opposite effect on BY-2 mitosis transition. Culture treatment with sodium orthovanadate during 1 h resulted in an accelerated start of the prophase and did not lead to the alteration in time of the mitotic index peak formation, as compared to control cells. We suppose that the reversible tyrosine phosphorylation can be involved in the regulation of interphase to M phase transition possibly through regulation of microtubule dynamics in plant cells.

  1. Sepsis-induced cardiac mitochondrial dysfunction involves altered mitochondrial-localization of tyrosine kinase Src and tyrosine phosphatase SHP2.

    Directory of Open Access Journals (Sweden)

    Qun S Zang

    Full Text Available Our previous research demonstrated that sepsis produces mitochondrial dysfunction with increased mitochondrial oxidative stress in the heart. The present study investigated the role of mitochondria-localized signaling molecules, tyrosine kinase Src and tyrosine phosphatase SHP2, in sepsis-induced cardiac mitochondrial dysfunction using a rat pneumonia-related sepsis model. SD rats were given an intratracheal injection of Streptococcus pneumoniae, 4×10(6 CFU per rat, (or vehicle for shams; heart tissues were then harvested and subcellular fractions were prepared. By Western blot, we detected a gradual and significant decrease in Src and an increase in SHP2 in cardiac mitochondria within 24 hours post-inoculation. Furthermore, at 24 hours post-inoculation, sepsis caused a near 70% reduction in tyrosine phosphorylation of all cardiac mitochondrial proteins. Decreased tyrosine phosphorylation of certain mitochondrial structural proteins (porin, cyclophilin D and cytochrome C and functional proteins (complex II subunit 30kD and complex I subunit NDUFB8 were evident in the hearts of septic rats. In vitro, pre-treatment of mitochondrial fractions with recombinant active Src kinase elevated OXPHOS complex I and II-III activity, whereas the effect of SHP2 phosphatase was opposite. Neither Src nor SHP2 affected complex IV and V activity under the same conditions. By immunoprecipitation, we showed that Src and SHP2 consistently interacted with complex I and III in the heart, suggesting that complex I and III contain putative substrates of Src and SHP2. In addition, in vitro treatment of mitochondrial fractions with active Src suppressed sepsis-associated mtROS production and protected aconitase activity, an indirect marker of mitochondrial oxidative stress. On the contrary, active SHP2 phosphatase overproduced mtROS and deactivated aconitase under the same in vitro conditions. In conclusion, our data suggest that changes in mitochondria

  2. 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:... potentialregulators of macrophage inflammatory activities. PubmedID 12472665 Title Macrophage-stimulatin

  3. Interactions between Type III receptor tyrosine phosphatases and growth factor receptor tyrosine kinases regulate tracheal tube formation in Drosophila

    Directory of Open Access Journals (Sweden)

    Mili Jeon

    2012-04-01

    The respiratory (tracheal system of the Drosophila melanogaster larva is an intricate branched network of air-filled tubes. Its developmental logic is similar in some ways to that of the vertebrate vascular system. We previously described a unique embryonic tracheal tubulogenesis phenotype caused by loss of both of the Type III receptor tyrosine phosphatases (RPTPs, Ptp4E and Ptp10D. In Ptp4E Ptp10D double mutants, the linear tubes in unicellular and terminal tracheal branches are converted into bubble-like cysts that incorporate apical cell surface markers. This tube geometry phenotype is modulated by changes in the activity or expression of the epidermal growth factor receptor (Egfr tyrosine kinase (TK. Ptp10D physically interacts with Egfr. Here we demonstrate that the Ptp4E Ptp10D phenotype is the consequence of the loss of negative regulation by the RPTPs of three growth factor receptor TKs: Egfr, Breathless and Pvr. Reducing the activity of any of the three kinases by tracheal expression of dominant-negative mutants suppresses cyst formation. By competing dominant-negative and constitutively active kinase mutants against each other, we show that the three RTKs have partially interchangeable activities, so that increasing the activity of one kinase can compensate for the effects of reducing the activity of another. This implies that SH2-domain downstream effectors that are required for the phenotype are likely to be able to interact with phosphotyrosine sites on all three receptor TKs. We also show that the phenotype involves increases in signaling through the MAP kinase and Rho GTPase pathways.

  4. Targeting Bruton's tyrosine kinase signaling as an emerging therapeutic agent of B-cell malignancies.

    Science.gov (United States)

    Xia, Bing; Qu, Fulian; Yuan, Tian; Zhang, Yizhuo

    2015-12-01

    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 Bruton's tyrosine kinase (BTK). Ibrutinib, an oral irreversible BTK inhibitor, has emerged as a promising targeted therapy for patients with B-cell malignancies. The present review discusses the current understanding of BTK-mediated BCR signaling in the biology and pathobiology of normal and malignant B cells, and the cellular interaction with the tumor microenvironment. The data on ibrutinib in the preclinical and clinical settings is also discussed, and perspectives for the future use of ibrutinib are outlined.

  5. Reconstitution of Btk signaling by the atypical tec family tyrosine kinases Bmx and Txk.

    Science.gov (United States)

    Tomlinson, M G; Kurosaki, T; Berson, A E; Fujii, G H; Johnston, J A; Bolen, J B

    1999-05-07

    Bruton's tyrosine kinase (Btk) is mutated in X-linked agammaglobulinemia patients and plays an essential role in B cell receptor signal transduction. Btk is a member of the Tec family of nonreceptor protein-tyrosine kinases that includes Bmx, Itk, Tec, and Txk. Cell lines deficient for Btk are impaired in phospholipase C-gamma2 (PLCgamma2)-dependent signaling. Itk and Tec have recently been shown to reconstitute PLCgamma2-dependent signaling in Btk-deficient human cells, but it is not known whether the atypical Tec family members, Bmx and Txk, can reconstitute function. Here we reconstitute Btk-deficient DT40 B cells with Bmx and Txk to compare their function with other Tec kinases. We show that in common with Itk and Tec, Bmx reconstituted PLCgamma2-dependent responses including calcium mobilization, extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) activation, and apoptosis. Txk also restored PLCgamma2/calcium signaling but, unlike other Tec kinases, functioned in a phosphatidylinositol 3-kinase-independent manner and failed to reconstitute apoptosis. These results are consistent with a common role for Tec kinases as amplifiers of PLCgamma2-dependent signal transduction, but suggest that the pleckstrin homology domain of Tec kinases, absent in Txk, is essential for apoptosis.

  6. Quinoxaline-Based Scaffolds Targeting Tyrosine Kinases and Their Potential Anticancer Activity.

    Science.gov (United States)

    El Newahie, Aliya M S; Ismail, Nasser S M; Abou El Ella, Dalal A; Abouzid, Khaled A M

    2016-05-01

    Quinoxaline derivatives, also called benzopyrazines, are an important class of heterocyclic compounds. Quinoxalines have drawn great attention due to their wide spectrum of biological activities. They are considered as an important basis for anticancer drugs due to their potential activity as protein kinase inhibitors. In this review, we focus on the chemistry of the quinoxaline derivatives, the strategies for their synthesis, their potential activities against various tyrosine kinases, and on the structure-activity relationship studies reported to date.

  7. Role of the Yes and Csk tyrosine kinases in the development of a pathological state in the human retina.

    Science.gov (United States)

    Baranova, Lyudmila; Emelyanova, Valentina; Volotovski, Igor

    2010-07-01

    Amplification and a cloning of fragments of genes of human retina tyrosine kinases, the nucleotide sequences of which feature a high homology to the gene families of the Yes and Csk tyrosine kinases, and a cloning of the complete coding sequence of the cDNA of the Csk tyrosine kinase gene of the human lymphocytes have been carried out. It has been established that this sequence contains 1,624 bp and encodes a protein that, with a 99% homology, corresponds to the human tyrosine kinase. A comparative analysis of the nucleotide sequences of the full-size cDNA of the Csk tyrosine kinase of the lymphocytes of healthy donors and of patients with an eye choroidal melanoma has shown that a risk of development of an eye choroidal melanoma can be estimated by the frequency of occurrence of a mutant allele in the 10th exon.

  8. Endothelial Bmx tyrosine kinase activity is essential for myocardial hypertrophy and remodeling.

    Science.gov (United States)

    Holopainen, Tanja; Räsänen, Markus; Anisimov, Andrey; Tuomainen, Tomi; Zheng, Wei; Tvorogov, Denis; Hulmi, Juha J; Andersson, Leif C; Cenni, Bruno; Tavi, Pasi; Mervaala, Eero; Kivelä, Riikka; Alitalo, Kari

    2015-10-20

    Cardiac hypertrophy accompanies many forms of heart disease, including ischemic disease, hypertension, heart failure, and valvular disease, and it is a strong predictor of increased cardiovascular morbidity and mortality. Deletion of bone marrow kinase in chromosome X (Bmx), an arterial nonreceptor tyrosine kinase, has been shown to inhibit cardiac hypertrophy in mice. This finding raised the possibility of therapeutic use of Bmx tyrosine kinase inhibitors, which we have addressed here by analyzing cardiac hypertrophy in gene-targeted mice deficient in Bmx tyrosine kinase activity. We found that angiotensin II (Ang II)-induced cardiac hypertrophy is significantly reduced in mice deficient in Bmx and in mice with inactivated Bmx tyrosine kinase compared with WT mice. Genome-wide transcriptomic profiling showed that Bmx inactivation suppresses myocardial expression of genes related to Ang II-induced inflammatory and extracellular matrix responses whereas expression of RNAs encoding mitochondrial proteins after Ang II administration was maintained in Bmx-inactivated hearts. Very little or no Bmx mRNA was expressed in human cardiomyocytes whereas human cardiac endothelial cells expressed abundant amounts. Ang II stimulation of endothelial cells increased Bmx phosphorylation, and Bmx gene silencing inhibited downstream STAT3 signaling, which has been implicated in cardiac hypertrophy. Furthermore, activation of the mechanistic target of rapamycin complex 1 pathway by Ang II treatment was decreased in the Bmx-deficient hearts. Our results demonstrate that inhibition of the cross-talk between endothelial cells and cardiomyocytes by Bmx inactivation suppresses Ang II-induced signals for cardiac hypertrophy. These results suggest that the endothelial Bmx tyrosine kinase could provide a target to attenuate the development of cardiac hypertrophy.

  9. 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

  10. Protein-Tyrosine Kinase Signaling in the Biological Functions Associated with Sperm

    Directory of Open Access Journals (Sweden)

    Takashi W. Ijiri

    2012-01-01

    Full Text Available In sexual reproduction, two gamete cells (i.e., egg and sperm fuse (fertilization to create a newborn with a genetic identity distinct from those of the parents. In the course of these developmental processes, a variety of signal transduction events occur simultaneously in each of the two gametes, as well as in the fertilized egg/zygote/early embryo. In particular, a growing body of knowledge suggests that the tyrosine kinase Src and/or other protein-tyrosine kinases are important elements that facilitate successful implementation of the aforementioned processes in many animal species. In this paper, we summarize recent findings on the roles of protein-tyrosine phosphorylation in many sperm-related processes (from spermatogenesis to epididymal maturation, capacitation, acrosomal exocytosis, and fertilization.

  11. 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...

  12. Tyrosine Kinase Ligand-Receptor Pair Prediction by Using Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Masayuki Yarimizu

    2015-01-01

    Full Text Available Receptor tyrosine kinases are essential proteins involved in cellular differentiation and proliferation in vivo and are heavily involved in allergic diseases, diabetes, and onset/proliferation of cancerous cells. Identifying the interacting partner of this protein, a growth factor ligand, will provide a deeper understanding of cellular proliferation/differentiation and other cell processes. In this study, we developed a method for predicting tyrosine kinase ligand-receptor pairs from their amino acid sequences. We collected tyrosine kinase ligand-receptor pairs from the Database of Interacting Proteins (DIP and UniProtKB, filtered them by removing sequence redundancy, and used them as a dataset for machine learning and assessment of predictive performance. Our prediction method is based on support vector machines (SVMs, and we evaluated several input features suitable for tyrosine kinase for machine learning and compared and analyzed the results. Using sequence pattern information and domain information extracted from sequences as input features, we obtained 0.996 of the area under the receiver operating characteristic curve. This accuracy is higher than that obtained from general protein-protein interaction pair predictions.

  13. Tyrosine kinase inhibitors target cancer stem cells in renal cell cancer.

    Science.gov (United States)

    Czarnecka, Anna M; Solarek, Wojciech; Kornakiewicz, Anna; Szczylik, Cezary

    2016-03-01

    This study was designed to analyze the impact of multi-targeted tyrosine kinase inhibitors on the cancer stem cell subpopulation in renal cell cancer. The second objective was to evaluate the effect of tumor growth inhibition related to a tumor niche factor - oxygen deprivation - as hypoxia develops along with the anti-angiogenic activity of tyrosine kinase inhibitors in renal tumors. Cells were treated with tyrosine kinase inhibitors, sunitinib, sorafenib and axitinib, in 2D and 3D culture conditions. Cell proliferation along with drug toxicity were evaluated. It was shown that the proliferation rate of cancer stem cells was decreased by the tyrosine kinase inhibitors. The efficacy of the growth inhibition was limited by hypoxic conditions and 3D intratumoral cell-cell interactions. We conclude that understanding the complex molecular interaction feedback loops between differentiated cancer cells, cancer stem cells and the tumor microenvironment in 3D culture should aid the identification of novel treatment targets and to evalute the efficacy of renal cancer therapies. Cell-cell interaction may represent a critical microenvironmental factor regulating cancer stem cell self-renewal potential, enhancing the stem cell phenotype and limiting drug toxicity. At the same time the role of hypoxia in renal cancer stem cell biology is also significant.

  14. The Effects of Four Different Tyrosine Kinase Inhibitors on Medullary and Papillary Thyroid Cancer Cells

    NARCIS (Netherlands)

    Verbeek, Hans H. G.; Alves, Maria M.; de Groot, Jan-Willem B.; Osinga, Jan; Plukker, John T. M.; Links, Thera P.; Hofstra, Robert M. W.

    Context: Medullary and papillary thyroid carcinoma (MTC and PTC) are two types of thyroid cancer that can originate from activating mutations or rearrangements in the RET gene. Therapeutic options are limited in recurrent disease, but because RET is a tyrosine kinase (TK) receptor involved in

  15. Impaired precursor B cell differentiation in Bruton's tyrosine kinase-deficient mice

    NARCIS (Netherlands)

    S. Middendorp; G.M. Dingjan (Gemma); R.W. Hendriks (Rudi)

    2002-01-01

    textabstractBruton's tyrosine kinase (Btk) is a cytoplasmic signaling molecule that is crucial for precursor (pre-B) cell differentiation in humans. In this study, we show that during the transition of large cycling to small resting pre-B cells in the mouse, Btk-deficient cells fai

  16. The tyrosine kinase inhibitor sunitinib affects ovulation but not ovarian reserve in mouse: A preclinical study

    NARCIS (Netherlands)

    V. Bernard (Valérie); J. Bouilly (Justine); P. Kramer (Piet); N. Carré (Nadège); M. Schlumberger (Martin); J.A. Visser (Jenny A.); J. Young (Jacques); N.B. Binart (Nadine Binart)

    2016-01-01

    textabstractThe aim of the study was to evaluate ovarian toxicity of tyrosine kinase inhibitor (TKI) sunitinib, since only scarce data are available on gonadal function after this treatment. Six-weekold female mice received orally, once daily, vehicle or sunitinib (50 mg/kg/d) during 5 weeks.

  17. 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

    Growth hormone (GH) has recently been shown to activate the GH receptor (GHR)-associated tyrosine kinase JAK2. In the present study, regions of the GHR required for JAK2 association with GHR were identified. GH-dependent JAK2 association with GHR was detected in Chinese hamster ovary (CHO) cells...

  18. Factors Influencing Adherence in Cancer Patients Taking Oral Tyrosine Kinase Inhibitors: A Qualitative Study.

    Science.gov (United States)

    Verbrugghe, Mathieu; Duprez, Veerle; Beeckman, Dimitri; Grypdonck, Mieke; Quaghebeur, Marijke; Verschueren, Caroline; Verhaeghe, Sofie; Van Hecke, Ann

    2016-01-01

    Nonadherence in cancer patients taking oral anticancer drugs is common. Reasons for nonadherence are still not really understood as influencing factors are often complex, dynamic, and interrelated. A qualitative study was conducted to gain insight into (non-)adherence behavior in patients taking oral tyrosine kinase inhibitors by exploring (1) processes and factors influencing (non-)adherence and (2) their interrelatedness. Semistructured interviews were held with 30 patients of different ages and with different types of cancer. A grounded theory approach was used. Three foci were found when dealing with oral tyrosine kinase inhibitors: (1) a focus on survival, (2) a focus on quality of life, and (3) a balance between survival and quality of life. The process of adherence was determined by a set of complex and interrelated influencing factors: treatment-related side effects, hope, anxiety, trust, and feedback mechanisms. This qualitative study gives insight into processes and factors influencing (non-)adherence behavior in patients taking oral tyrosine kinase inhibitors. The results of this study can help healthcare professionals understand why patients taking oral tyrosine kinase inhibitors do not always adhere to their therapy. Conditions should be created by which patients get maximum opportunity to establish a balance between survival and quality of life. An open climate and a trust-based relationship should be established in which patients feel comfortable to openly discuss their therapy and the difficulties they experience.

  19. 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 ...

  20. Tumor suppressor function of Bruton tyrosine kinase is independent of its catalytic activity

    NARCIS (Netherlands)

    S. Middendorp; A.J.E. Zijlstra (Esther); R. Kersseboom (Rogier); G.M. Dingjan (Gemma); H. Jumaa; R.W. Hendriks (Rudi)

    2005-01-01

    textabstractDuring B-cell development in the mouse, Bruton tyrosine kinase (Btk) and the adaptor protein SLP-65 (Src homology 2 [SH2] domain-containing leukocyte protein of 65 kDa) limit the expansion and promote the differentiation of pre-B cells. Btk is thought to mainly function

  1. Impaired precursor B cell differentiation in Bruton's tyrosine kinase-deficient mice

    NARCIS (Netherlands)

    S. Middendorp; G.M. Dingjan (Gemma); R.W. Hendriks (Rudi)

    2002-01-01

    textabstractBruton's tyrosine kinase (Btk) is a cytoplasmic signaling molecule that is crucial for precursor (pre-B) cell differentiation in humans. In this study, we show that during the transition of large cycling to small resting pre-B cells in the mouse, Btk-deficient cells

  2. Metabolite profiling of the multiple tyrosine kinase inhibitor lenvatinib : a cross-species comparison

    NARCIS (Netherlands)

    Dubbelman, Anne Charlotte; Nijenhuis, Cynthia M.; Jansen, Robert S; Rosing, Hilde; Mizuo, Hitoshi; Kawaguchi, Shinki; Critchley, David; Shumaker, Robert; Schellens, Jan H M; Beijnen, Jos H.

    2016-01-01

    Lenvatinib is an oral, multiple receptor tyrosine kinase inhibitor. Preclinical drug metabolism studies showed unique metabolic pathways for lenvatinib in monkeys and rats. A human mass balance study demonstrated that lenvatinib related material is mainly excreted via feces with a small fraction as

  3. Structural basis for the regulation mechanism of the tyrosine kinase CapB from Staphylococcus aureus

    DEFF Research Database (Denmark)

    Olivares-Illana, Vanesa; Meyer, Philippe; Bechet, Emmanuelle

    2008-01-01

    understood due to slow progress in their structural characterization. They have been best characterized as copolymerases involved in the synthesis and export of extracellular polysaccharides. These compounds play critical roles in the virulence of pathogenic bacteria, and bacterial tyrosine kinases can thus...

  4. Defining Human Tyrosine Kinase Phosphorylation Networks Using Yeast as an In Vivo Model Substrate.

    Science.gov (United States)

    Corwin, Thomas; Woodsmith, Jonathan; Apelt, Federico; Fontaine, Jean-Fred; Meierhofer, David; Helmuth, Johannes; Grossmann, Arndt; Andrade-Navarro, Miguel A; Ballif, Bryan A; Stelzl, Ulrich

    2017-08-23

    Systematic assessment of tyrosine kinase-substrate relationships is fundamental to a better understanding of cellular signaling and its profound alterations in human diseases such as cancer. In human cells, such assessments are confounded by complex signaling networks, feedback loops, conditional activity, and intra-kinase redundancy. Here we address this challenge by exploiting the yeast proteome as an in vivo model substrate. We individually expressed 16 human non-receptor tyrosine kinases (NRTKs) in Saccharomyces cerevisiae and identified 3,279 kinase-substrate relationships involving 1,351 yeast phosphotyrosine (pY) sites. Based on the yeast data without prior information, we generated a set of linear kinase motifs and assigned ∼1,300 known human pY sites to specific NRTKs. Furthermore, experimentally defined pY sites for each individual kinase were shown to cluster within the yeast interactome network irrespective of linear motif information. We therefore applied a network inference approach to predict kinase-substrate relationships for more than 3,500 human proteins, providing a resource to advance our understanding of kinase biology. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. EphB4 Receptor Tyrosine Kinase in Prostate Cancer

    Science.gov (United States)

    2011-09-01

    Hassanieh  L,   Ley  EJ,  Scehnet  J,  Kumar  NG,   Hawes  D,  Press  MF,  Weaver  FA,  Gill  PS.  Receptor  tyrosine...J. Pathol. 174 (2009) 1492. [33] T.D. Bartley, R.W. Hunt, A.A. Welcher, W.J. Boyle , V.P. Parker, R.A. Lindberg, H.S. Lu, A.M. Colombero, R.L

  6. Attenuation of endothelin-1-induced calcium response by tyrosine kinase inhibitors in vascular smooth muscle cells.

    Science.gov (United States)

    Liu, C Y; Sturek, M

    1996-06-01

    Although tyrosine kinases play an important role in cell growth and have been implicated in regulation of smooth muscle contraction, their role in agonist-induced myoplasmic Ca2+ responses is unclear. We examined effects of the tyrosine kinase inhibitors genistein and methyl 2,5-dihydroxycinnamate (MDHC) on the endothelin-1 (ET-1)-induced Ca2+ response and determined underlying mechanisms for the effects. Freshly isolated smooth muscle cells from porcine coronary arteries were loaded with fura 2 ester, and myoplasmic free Ca2+ (Ca2+ (m)) concentration was estimated with fura 2 microfluorometry. Both genistein and MDHC inhibited the initial transient Cam2+ response to ET by 54 and 81%, respectively (P latent period from ET-1 application to the beginning of the Cam2+ response being increased from 1.08 +/- 0.17 to 2.65 +/- 0.52 min (P < 0.05). In the absence of extracellular Ca2+, genistein inhibited the ET-1-induced Cam2+ response by 93% (P < 0.05). The Cam2+ responses to caffeine (5 mM) or inositol trisphosphate (IP3) applied intracellularly via a patch-clamp pipette were not affected by genistein. Both genistein and MDHC also abolished the sustained Cam2+ response to ET-1. However, the Cam2+ response to depolarization by 80 mM K+ was not inhibited by MDHC and only inhibited 22% by genistein (P < 0.05). These results indicate that 1) activation of tyrosine kinases is an important regulatory mechanism for the ET-1-induced Cam2+ response in vascular smooth muscle and 2) tyrosine kinases mediate ET-1-induced Ca2+ release with no direct effect on IP3-mediated Ca2+ release. Thus ET-1-mediated signaling upstream of IP3 interaction with the Ca2+ stores is regulated by tyrosine kinases.

  7. 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.

  8. ACK1/TNK2 tyrosine kinase: molecular signaling and evolving role in cancers.

    Science.gov (United States)

    Mahajan, K; Mahajan, N P

    2015-08-01

    Deregulated tyrosine kinase signaling alters cellular homeostasis to drive cancer progression. The emergence of a non-receptor tyrosine kinase (non-RTK), ACK1 (also known as activated Cdc42-associated kinase 1 or TNK2) as an oncogenic kinase, has uncovered novel mechanisms by which tyrosine kinase signaling promotes cancer progression. Although early studies focused on ACK1 as a cytosolic effector of activated transmembrane RTKs, wherein it shuttles between the cytosol and the nucleus to rapidly transduce extracellular signals from the RTKs to the intracellular effectors, recent data unfold a new aspect of its functionality as an epigenetic regulator. ACK1 interacts with the estrogen receptor (ER)/histone demethylase KDM3A (JHDM2a) complex, which modifies KDM3A by tyrosine phosphorylation to regulate the transcriptional outcome at HOXA1 locus to promote the growth of tamoxifen-resistant breast cancer. It is also well established that ACK1 regulates the activity of androgen receptor (AR) by tyrosine phosphorylation to fuel the growth of hormone-refractory prostate cancers. Further, recent explosion in genomic sequencing has revealed recurrent ACK1 gene amplification and somatic mutations in a variety of human malignancies, providing a molecular basis for its role in neoplastic transformation. In this review, we will discuss the various facets of ACK1 signaling, including its newly uncovered epigenetic regulator function, which enables cells to bypass the blockade to major survival pathways to promote resistance to standard cancer treatments. Not surprisingly, cancer cells appear to acquire an 'addiction' to ACK1-mediated survival, particularly under stress conditions, such as growth factor deprivation or genotoxic insults or hormone deprivation. With the accelerated development of potent and selective ACK1 inhibitors, targeted treatment for cancers harboring aberrant ACK1 activity may soon become a clinical reality.

  9. Ethyl p-methoxycinnamate from Kaempferia galanga inhibits angiogenesis through tyrosine kinase

    Directory of Open Access Journals (Sweden)

    Juni Ekowati

    2015-04-01

    Full Text Available Background Many tumors express on their receptor tyrosine kinases vascular endothelial growth factor activity associated with angiogenesis. Inhibition of angiogenesis through reduction of tyrosine kinase activity is a promising strategy for cancer therapy. The present study aimed to determine the mechanism and potency of ethyl p-methoxycinnamate (EPMC isolated from Kaempferia galanga as angiogenesis inhibitor. Methods A laboratory experimental study was conducted using chorio-allantoic membranes (CAMs of nine-day old chicken eggs induced by 60ng basic fibroblast growth factor (bFGF. Ethyl p-methoxycinnamate (EPMC potency was determined at dosages of 30, 60, 90 and 120 mg and compared with celecoxib 60 mg as reference drug and one negative bFGF-induced control group. Neovascularization and endothelial cell count in CAM blood vessels were evaluated. To predict the antiangiogenic mechanism of EPMC, a docking study was performed with the Molegro Virtual Docker program on tyrosine kinase as receptor (PDB 1XKK. Results Angiogenesis stimulation by bFGF was prevented significantly (p<0.05 by EPMC at dosages of 30, 60, 90 and 120 mg and this activity was dose dependent. Molecular docking showed interaction between EPMC functional groups and tyrosine kinase amino acids at Met766, Met793, Thr854, Thr790, Gln791 and Ala743. There was an association between EPMC antiangiogenic activity and docking study results. Conclusions Ethyl p-methoxycinnamate is a potential new angiogenesis inhibitor through interaction with tyrosine kinase. EPMC could be a promising therapeutic agent for treatment of angiogenesis-related diseases.

  10. Regulation of the EphA2 kinase by the low molecular weight tyrosine phosphatase induces transformation.

    Science.gov (United States)

    Kikawa, Keith D; Vidale, Derika R; Van Etten, Robert L; Kinch, Michael S

    2002-10-18

    Intracellular signaling by protein tyrosine phosphorylation is generally understood to govern many aspects of cellular behavior. The biological consequences of this signaling pathway are important because the levels of protein tyrosine phosphorylation are frequently elevated in cancer cells. In the classic paradigm, tyrosine kinases promote tumor cell growth, survival, and invasiveness, whereas tyrosine phosphatases negatively regulate these same behaviors. Here, we identify one particular tyrosine phosphatase, low molecular weight tyrosine phosphatase (LMW-PTP), which is frequently overexpressed in transformed cells. We also show that overexpression of LMW-PTP is sufficient to confer transformation upon non-transformed epithelial cells. Notably, we show that the EphA2 receptor tyrosine kinase is a prominent substrate for LMW-PTP and that the oncogenic activities of LMW-PTP result from altered EphA2 expression and function. These results suggest a role for LMW-PTP in transformation progression and link its oncogenic potential to EphA2.

  11. PREX1 Protein Function Is Negatively Regulated Downstream of Receptor Tyrosine Kinase Activation by p21-activated Kinases (PAKs).

    Science.gov (United States)

    Barrows, Douglas; He, John Z; Parsons, Ramon

    2016-09-16

    Downstream of receptor tyrosine kinase and G protein-coupled receptor (GPCR) stimulation, the phosphatidylinositol 3,4,5-trisphosphate (PIP3)-dependent Rac exchange factor (PREX) family of guanine nucleotide exchange factors (GEFs) activates Rho GTPases, leading to important roles for PREX proteins in numerous cellular processes and diseases, including cancer. PREX1 and PREX2 GEF activity is activated by the second messengers PIP3 and Gβγ, and further regulation of PREX GEF activity occurs by phosphorylation. Stimulation of receptor tyrosine kinases by neuregulin and insulin-like growth factor 1 (IGF1) leads to the phosphorylation of PREX1; however, the kinases that phosphorylate PREX1 downstream of these ligands are not known. We recently reported that the p21-activated kinases (PAKs), which are activated by GTP-bound Ras-related C3 botulinum toxin substrate 1 (Rac1), mediate the phosphorylation of PREX2 after insulin receptor activation. Here we show that certain phosphorylation events on PREX1 after insulin, neuregulin, and IGF1 treatment are PAK-dependent and lead to a reduction in PREX1 binding to PIP3 Like PREX2, PAK-mediated phosphorylation also negatively regulates PREX1 GEF activity. Furthermore, the onset of PREX1 phosphorylation was delayed compared with the phosphorylation of AKT, supporting a model of negative feedback downstream of PREX1 activation. We also found that the phosphorylation of PREX1 after isoproterenol and prostaglandin E2-mediated GPCR activation is partially PAK-dependent and likely also involves protein kinase A, which is known to reduce PREX1 function. Our data point to multiple mechanisms of PREX1 negative regulation by PAKs within receptor tyrosine kinase and GPCR-stimulated signaling pathways that have important roles in diseases such as diabetes and cancer.

  12. Identification of nitrated tyrosine residues of protein kinase G-Iα by mass spectrometry.

    Science.gov (United States)

    Lu, Jingshan; Yao, Ikuko; Shimojo, Masahito; Katano, Tayo; Uchida, Hitoshi; Setou, Mitsutoshi; Ito, Seiji

    2014-02-01

    The nitration of tyrosine to 3-nitrotyrosine is an oxidative modification of tyrosine by nitric oxide and is associated with many diseases, and targeting of protein kinase G (PKG)-I represents a potential therapeutic strategy for pulmonary hypertension and chronic pain. The direct assignment of tyrosine residues of PKG-I has remained to be made due to the low sensitivity of the current proteomic approach. In order to assign modified tyrosine residues of PKG-I, we nitrated purified PKG-Iα expressed in insect Sf9 cells by use of peroxynitrite in vitro and analyzed the trypsin-digested fragments by matrix-assisted laser desorption/ionization-time of flight mass spectrometry and liquid chromatography-tandem mass spectrometry. Among the 21 tyrosine residues of PKG-Iα, 16 tyrosine residues were assigned in 13 fragments; and six tyrosine residues were nitrated, those at Y71, Y141, Y212, Y336, Y345, and Y567, in the peroxynitrite-treated sample. Single mutation of tyrosine residues at Y71, Y212, and Y336 to phenylalanine significantly reduced the nitration of PKG-Iα; and four mutations at Y71, Y141, Y212, and Y336 (Y4F mutant) reduced it additively. PKG-Iα activity was inhibited by peroxynitrite in a concentration-dependent manner from 30 μM to 1 mM, and this inhibition was attenuated in the Y4F mutant. These results demonstrated that PKG-Iα was nitrated at multiple tyrosine residues and that its activity was reduced by nitration of these residues.

  13. Identification and Targeting of Upstream Tyrosine Kinases Mediating PI3 Kinase Activation in PTEN Deficient Prostate Cancer

    Science.gov (United States)

    2011-06-01

    pAkt, phospho-Akt; Ab, antibody ; EGFR, epidermal growth factor receptor; ERK, extracellular signal-regulated kinase; GPCR , G protein-coupled receptor...tyrosine phosphorylated proteins, but they were not recognized by an anti-pYxxM motif antibody and were not found in PTEN deficient PC3 PCa cells. LC/MS/MS...immunoblotted the p85 immunoprecipitates with a pYxxM motif specific antibody . This antibody weakly detected several discrete p85 associated proteins

  14. Src kinases and ERK activate distinct responses to Stitcher receptor tyrosine kinase signaling during wound healing in Drosophila.

    Science.gov (United States)

    Tsarouhas, Vasilios; Yao, Liqun; Samakovlis, Christos

    2014-04-15

    Metazoans have evolved efficient mechanisms for epidermal repair and survival following injury. Several cellular responses and key signaling molecules that are involved in wound healing have been identified in Drosophila, but the coordination of cytoskeletal rearrangements and the activation of gene expression during barrier repair are poorly understood. The Ret-like receptor tyrosine kinase (RTK) Stitcher (Stit, also known as Cad96Ca) regulates both re-epithelialization and transcriptional activation by Grainy head (Grh) to induce restoration of the extracellular barrier. Here, we describe the immediate downstream effectors of Stit signaling in vivo. Drk (Downstream of receptor kinase) and Src family tyrosine kinases bind to the same docking site in the Stit intracellular domain. Drk is required for the full activation of transcriptional responses but is dispensable for re-epithelialization. By contrast, Src family kinases (SFKs) control both the assembly of a contractile actin ring at the wound periphery and Grh-dependent activation of barrier-repair genes. Our analysis identifies distinct pathways mediating injury responses and reveals an RTK-dependent activation mode for Src kinases and their central functions during epidermal wound healing in vivo.

  15. Functional interaction of caveolin-1 with Bruton's tyrosine kinase and Bmx.

    Science.gov (United States)

    Vargas, Leonardo; Nore, Beston F; Berglof, Anna; Heinonen, Juhana E; Mattsson, Pekka T; Smith, C I Edvard; Mohamed, Abdalla J

    2002-03-15

    Bruton's tyrosine kinase (Btk), a member of the Tec family of protein-tyrosine kinases, has been shown to be crucial for B cell development, differentiation, and signaling. Mutations in the Btk gene lead to X-linked agammaglobulinemia in humans and X-linked immunodeficiency in mice. Using a co-transfection approach, we present evidence here that Btk interacts physically with caveolin-1, a 22-kDa integral membrane protein, which is the principal structural and regulatory component of caveolae membranes. In addition, we found that native Bmx, another member of the Tec family kinases, is associated with endogenous caveolin-1 in primary human umbilical vein endothelial cells. Second, in transient transfection assays, expression of caveolin-1 leads to a substantial reduction in the in vivo tyrosine phosphorylation of both Btk and its constitutively active form, E41K. Furthermore, a caveolin-1 scaffolding peptide (amino acids 82--101) functionally suppressed the autokinase activity of purified recombinant Btk protein. Third, we demonstrate that mouse splenic B-lymphocytes express substantial amounts of caveolin-1. Interestingly, caveolin-1 was found to be constitutively phosphorylated on tyrosine 14 in these cells. The expression of caveolin-1 in B-lymphocytes and its interaction with Btk may have implications not only for B cell activation and signaling, but also for antigen presentation.

  16. Hydrophobic Core Variations Provide a Structural Framework for Tyrosine Kinase Evolution and Functional Specialization.

    Science.gov (United States)

    Mohanty, Smita; Oruganty, Krishnadev; Kwon, Annie; Byrne, Dominic P; Ferries, Samantha; Ruan, Zheng; Hanold, Laura E; Katiyar, Samiksha; Kennedy, Eileen J; Eyers, Patrick A; Kannan, Natarajan

    2016-02-01

    Protein tyrosine kinases (PTKs) are a group of closely related enzymes that have evolutionarily diverged from serine/threonine kinases (STKs) to regulate pathways associated with multi-cellularity. Evolutionary divergence of PTKs from STKs has occurred through accumulation of mutations in the active site as well as in the commonly conserved hydrophobic core. While the functional significance of active site variations is well understood, relatively little is known about how hydrophobic core variations contribute to PTK evolutionary divergence. Here, using a combination of statistical sequence comparisons, molecular dynamics simulations, mutational analysis and in vitro thermostability and kinase assays, we investigate the structural and functional significance of key PTK-specific variations in the kinase core. We find that the nature of residues and interactions in the hydrophobic core of PTKs is strikingly different from other protein kinases, and PTK-specific variations in the core contribute to functional divergence by altering the stability and dynamics of the kinase domain. In particular, a functionally critical STK-conserved histidine that stabilizes the regulatory spine in STKs is selectively mutated to an alanine, serine or glutamate in PTKs, and this loss-of-function mutation is accommodated, in part, through compensatory PTK-specific interactions in the core. In particular, a PTK-conserved phenylalanine in the I-helix appears to structurally and functionally compensate for the loss of STK-histidine by interacting with the regulatory spine, which has far-reaching effects on enzyme activity, inhibitor sensing, and stability. We propose that hydrophobic core variations provide a selective advantage during PTK evolution by increasing the conformational flexibility, and therefore the allosteric potential of the kinase domain. Our studies also suggest that Tyrosine Kinase Like kinases such as RAF are intermediates in PTK evolutionary divergence inasmuch as they

  17. A tyrosine phosphorylation switch controls the interaction between the transmembrane modulator protein Wzd and the tyrosine kinase Wze of Lactobacillus rhamnosus.

    Science.gov (United States)

    Kang, Hye-Ji; Gilbert, Christophe; Badeaux, Frédérique; Atlan, Danièle; LaPointe, Gisèle

    2015-02-21

    One proposed mechanism for assembly of secreted heteropolysaccharides by many Gram positive bacteria relies on the coordinated action of a polymerization complex through reversible phosphorylation events. The role of the tyrosine protein kinase transmembrane modulator is, however, not well understood. The protein sequences deduced from the wzb, wzd and wze genes from Lactobacillus rhamnosus ATCC 9595 and RW-9595 M contain motifs also found in corresponding proteins CpsB, CpsC and CpsD from Streptococcus pneumoniae D39 (serotype 2). Use of an anti-phosphotyrosine antibody demonstrated that both Wzd and Wze can be found in tyrosine phosphorylated form. When tyrosine 266 was mutated to phenylalanine, WzdY266F showed slightly less phosphorylated protein than those produced by using eight other tyrosine mutated Wzd genes, when expressed along with Wze and Wzb in Lactococcus lactis subsp. cremoris MG1363. In order to demonstrate the importance of ATP for the interactions among these proteins, native and fusion Wzb, Wzd and Wze proteins were expressed and purified from Escherichia coli cultures. The modulator protein, Wzd, binds with the phosphotyrosine kinase Wze, irrespective of its phosphorylation status. However, Wze attained a higher phosphorylation level after interacting with phosphorylated Wzd in the presence of 10 mM ATP. This highly phosphorylated Wze did not remain in close association with phosphorylated Wzd. The Wze tyrosine kinase protein of Lactobacillus rhamnosus thus carries out tyrosine phosphorylation of Wzd in addition to auto- and trans- phosphorylation of the kinase itself.

  18. Neuroblastoma tyrosine kinase signaling networks involve FYN and LYN in endosomes and lipid rafts.

    Directory of Open Access Journals (Sweden)

    Juan Palacios-Moreno

    2015-04-01

    Full Text Available Protein phosphorylation plays a central role in creating a highly dynamic network of interacting proteins that reads and responds to signals from growth factors in the cellular microenvironment. Cells of the neural crest employ multiple signaling mechanisms to control migration and differentiation during development. It is known that defects in these mechanisms cause neuroblastoma, but how multiple signaling pathways interact to govern cell behavior is unknown. In a phosphoproteomic study of neuroblastoma cell lines and cell fractions, including endosomes and detergent-resistant membranes, 1622 phosphorylated proteins were detected, including more than half of the receptor tyrosine kinases in the human genome. Data were analyzed using a combination of graph theory and pattern recognition techniques that resolve data structure into networks that incorporate statistical relationships and protein-protein interaction data. Clusters of proteins in these networks are indicative of functional signaling pathways. The analysis indicates that receptor tyrosine kinases are functionally compartmentalized into distinct collaborative groups distinguished by activation and intracellular localization of SRC-family kinases, especially FYN and LYN. Changes in intracellular localization of activated FYN and LYN were observed in response to stimulation of the receptor tyrosine kinases, ALK and KIT. The results suggest a mechanism to distinguish signaling responses to activation of different receptors, or combinations of receptors, that govern the behavior of the neural crest, which gives rise to neuroblastoma.

  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 phosphorylation of the BRI1 receptor kinase occurs via a posttranslational modification and is activated by the juxtamembrane domain

    Science.gov (United States)

    In metazoans, receptor kinases control many essential processes related to growth and development and response to the environment. The receptor kinases in plants and animals are structurally similar but evolutionarily distinct from one another, and thus while most animal receptor kinases are tyrosin...

  1. TEC protein tyrosine kinase is involved in the Erk signaling pathway induced by HGF

    Energy Technology Data Exchange (ETDEWEB)

    Li, Feifei; Jiang, Yinan [Department of Pathophysiology, Anhui Medical University, Hefei 230032 (China); Zheng, Qiping [Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago, IL 60612 (United States); Yang, Xiaoming [Institute of Radiation Medicine, Academy of Military Medical Sciences, Beijing 100850 (China); Wang, Siying, E-mail: sywang@ahmu.edu.cn [Department of Pathophysiology, Anhui Medical University, Hefei 230032 (China)

    2011-01-07

    Research highlights: {yields} TEC is rapidly tyrosine-phosphorylated and activated by HGF-stimulation in vivo or after partial hepatectomy in mice. {yields} TEC enhances the activity of Elk and serum response element (SRE) in HGF signaling pathway in hepatocyte. {yields} TEC promotes hepatocyte proliferation through the Erk-MAPK pathway. -- Abstract: Background/aims: TEC, a member of the TEC family of non-receptor type protein tyrosine kinases, has recently been suggested to play a role in hepatocyte proliferation and liver regeneration. This study aims to investigate the putative mechanisms of TEC kinase regulation of hepatocyte differentiation, i.e. to explore which signaling pathway TEC is involved in, and how TEC is activated in hepatocyte after hepatectomy and hepatocyte growth factor (HGF) stimulation. Methods: We performed immunoprecipitation (IP) and immunoblotting (IB) to examine TEC tyrosine phosphorylation after partial hepatectomy in mice and HGF stimulation in WB F-344 hepatic cells. The TEC kinase activity was determined by in vitro kinase assay. Reporter gene assay, antisense oligonucleotide and TEC dominant negative mutant (TEC{sup KM}) were used to examine the possible signaling pathways in which TEC is involved. The cell proliferation rate was evaluated by {sup 3}H-TdR incorporation. Results: TEC phosphorylation and kinase activity were increased in 1 h after hepatectomy or HGF treatment. TEC enhanced the activity of Elk and serum response element (SRE). Inhibition of MEK1 suppressed TEC phosphorylation. Blocking TEC activity dramatically decreased the activation of Erk. Reduced TEC kinase activity also suppressed the proliferation of WB F-344 cells. These results suggest TEC is involved in the Ras-MAPK pathway and acts between MEK1 and Erk. Conclusions: TEC promotes hepatocyte proliferation and regeneration and is involved in HGF-induced Erk signaling pathway.

  2. Tyrosine Kinase Inhibitors and Vascular Toxicity: Impetus for a Classification System?

    Science.gov (United States)

    Herrmann, Joerg

    2016-06-01

    The introduction of molecularly targeted therapies with tyrosine kinase inhibitors has revolutionized cancer therapy and has contributed to a steady decline in cancer-related mortality since the late 1990s. However, not only cardiac but also vascular toxicity has been reported for these agents, some as expected on-target effects (e.g., VEGF receptor inhibitors) and others as unanticipated events (e.g., BCR-Abl inhibitors). A sound understanding of these cardiovascular toxic effects is critical to advance mechanistic insight into vascular disease and clinical care. From a conceptual standpoint, there might be value in defining type I (permanent) and type II (transient) vascular toxicity. This review will focus on the tyrosine kinase inhibitors in current clinical use and their associated vascular side effects.

  3. Loss of Bmx nonreceptor tyrosine kinase prevents pressure overload-induced cardiac hypertrophy.

    Science.gov (United States)

    Mitchell-Jordan, Scherise A; Holopainen, Tanja; Ren, Shuxun; Wang, Sujing; Warburton, Sarah; Zhang, Michael J; Alitalo, Kari; Wang, Yibin; Vondriska, Thomas M

    2008-12-05

    Bmx nonreceptor tyrosine kinase has an established role in endothelial and lymphocyte signaling; however, its role in the heart is unknown. To determine whether Bmx participates in cardiac growth, we subjected mice deficient in the molecule (Bmx knockout mice) to transverse aortic constriction (TAC). In comparison with wild-type mice, which progressively developed massive hypertrophy following TAC, Bmx knockout mice were resistant to TAC-induced cardiac growth at the organ and cell level. Loss of Bmx preserved cardiac ejection fraction and decreased mortality following TAC. These findings are the first to demonstrate a necessary role for the Tec family of tyrosine kinases in the heart and reveal a novel regulator (Bmx) of pressure overload-induced hypertrophic growth.

  4. How tyrosine kinase inhibitors impair metabolism and endocrine system function: a systematic updated review.

    Science.gov (United States)

    Breccia, Massimo; Molica, Matteo; Alimena, Giuliana

    2014-12-01

    Tyrosine kinase inhibitors (TKIs) advent has deeply changed the outcome of chronic myeloid leukemia (CML) patients, with improved rates of response and overall survival. However, for this success some patients paid the price of a number of peculiar side effects, the so-called off-target side effects, specific for each one TKI. These effects are due to non-selective inhibition of other tyrosine kinase receptors, such as PDGFR, c-KIT, Src, VEGF. Consequences of this inhibition, some metabolic changes during the treatment with TKIs are reported. Aim of present review is to report metabolic changes and potential mechanisms involved in the pathogenesis related to imatinib, second (nilotinib and dasatinib) and third generation (bosutinib and ponatinib) TKIs.

  5. Ly-6A is required for T cell receptor expression and protein tyrosine kinase fyn activity.

    Science.gov (United States)

    Lee, S K; Su, B; Maher, S E; Bothwell, A L

    1994-05-01

    To characterize the function of the Ly-6A antigen in T cell activation, antisense Ly-6 RNA was expressed in a stably transfected antigen-specific T cell clone. Reduced Ly-6A expression results in inhibition of responses to antigen, anti-TCR (anti-T cell receptor) crosslinking and concanavalin A plus recombinant interleukin 1 and causes impairment of in vitro fyn tyrosine kinase activity. More substantial reduction of Ly-6A results in reduction of TCR expression. Analysis of mRNA species indicates that the reduction is specific for the TCR beta chain. These data demonstrate that Ly-6A may regulate TCR expression and may be involved in early events of T cell activation via regulation of fyn tyrosine kinase activity.

  6. 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...

  7. New cytotoxic bisindole alkaloids with protein tyrosine kinase inhibitory activity from a myxomycete Lycogala epidendrum.

    Science.gov (United States)

    Hosoya, Takahiro; Yamamoto, Yukinori; Uehara, Yoshimasa; Hayashi, Masahiko; Komiyama, Kanki; Ishibashi, Masami

    2005-06-02

    Two new bisindole alkaloids, 6-hydroxystaurosporinone (1) and 5,6-dihydroxyarcyriaflavin A (2) were isolated from field-collected fruit bodies of a myxomycete Lycogala epidendrum, along with eight known bisindoles (3-10). The structures of these new compounds were determined on the basis of spectroscopic data. Compounds 1 and 2 showed cytotoxicity against HeLa, Jurkat, and vincristine resistant KB/VJ300 cells, and compound 1, particularly, inhibited protein tyrosine kinase activity.

  8. Cross-membrane signal transduction of receptor tyrosine kinases (RTKs): from systems biology to systems pharmacology.

    Science.gov (United States)

    Benson, Neil; van der Graaf, Piet H; Peletier, Lambertus A

    2013-03-01

    Receptor tyrosine kinases are high-affinity cell surface receptors for many polypeptide growth factors, cytokines, and hormones. They straddle the cell wall and play an important role in cross-membrane signalling. We present a two-component systems pharmacology model based on the local physiology and identify characteristic features of its dynamics. We thus present a transparent tool for studying the effects of drug intervention and ways of administration on cross-membrane signalling through these receptors.

  9. Exploring the Hypersensitivity of PTEN Deleted Prostate Cancer Stem Cells to WEE1 Tyrosine Kinase Inhibitors

    Science.gov (United States)

    2015-12-01

    deletion Inhibitors/drugs ABL1 4% SAC, 2% AML Stomach adenocarcinoma (SAC), Acute myeloid leukemias (AML) Amplifications and missense mutations, Gene fusion...Rassool,F.V. (2013) Targeting abnormal DNA double-strand break repair in tyrosine kinase inhibitor-resistant chronic myeloid leukemias . Oncogene, 32, 1784...with the WEE1 inhibitor, MK1775. In contrast to LNCaP, MK1775 induces a differentiation like phenotype in the PTEN wildtype prostate cancer derived

  10. Discovery of Potent and Selective Tricyclic Inhibitors of Bruton's Tyrosine Kinase with Improved Druglike Properties.

    Science.gov (United States)

    Wang, Xiaojing; Barbosa, James; Blomgren, Peter; Bremer, Meire C; Chen, Jacob; Crawford, James J; Deng, Wei; Dong, Liming; Eigenbrot, Charles; Gallion, Steve; Hau, Jonathon; Hu, Huiyong; Johnson, Adam R; Katewa, Arna; Kropf, Jeffrey E; Lee, Seung H; Liu, Lichuan; Lubach, Joseph W; Macaluso, Jen; Maciejewski, Pat; Mitchell, Scott A; Ortwine, Daniel F; DiPaolo, Julie; Reif, Karin; Scheerens, Heleen; Schmitt, Aaron; Wong, Harvey; Xiong, Jin-Ming; Xu, Jianjun; Zhao, Zhongdong; Zhou, Fusheng; Currie, Kevin S; Young, Wendy B

    2017-06-08

    In our continued effort to discover and develop best-in-class Bruton's tyrosine kinase (Btk) inhibitors for the treatment of B-cell lymphomas, rheumatoid arthritis, and systemic lupus erythematosus, we devised a series of novel tricyclic compounds that improved upon the druglike properties of our previous chemical matter. Compounds exemplified by G-744 are highly potent, selective for Btk, metabolically stable, well tolerated, and efficacious in an animal model of arthritis.

  11. Loss of Bmx Non-Receptor Tyrosine Kinase Prevents Pressure Overload-Induced Cardiac Hypertrophy

    OpenAIRE

    2008-01-01

    Bmx non-receptor tyrosine kinase has an established role in endothelial and lymphocyte signaling, however its role in the heart is unknown. To determine whether Bmx participates in cardiac growth, we subjected mice deficient in the molecule (Bmx KO mice) to transverse aortic constriction (TAC). In comparison to WT mice, which progressively developed massive hypertrophy following TAC, Bmx KO mice were resistant to TAC-induced cardiac growth at the organ and cell level. Loss of Bmx preserved ca...

  12. Bmx Tyrosine Kinase Transgene Induces Skin Hyperplasia, Inflammatory Angiogenesis, and Accelerated Wound Healing

    OpenAIRE

    2004-01-01

    The Bmx gene, a member of the Tec family of nonreceptor protein tyrosine kinases, is expressed in arterial endothelium and in certain hematopoietic and epithelial cells. Previous in vitro studies have implicated Bmx signaling in cell migration and survival and suggested that it contributes to the progression of prostate carcinomas. However, the function of Bmx in normal tissues in vivo is unknown. We show here that Bmx expression is induced in skin keratinocytes during wound healing. To analy...

  13. Receptor tyrosine kinase signaling regulates replication of the peste des petits ruminants virus.

    Science.gov (United States)

    Chaudhary, K; Chaubey, K K; Singh, S V; Kumar, N

    2015-03-01

    In this study, we found out that blocking the receptor tyrosine kinase (RTK) signaling in Vero cells by tryphostin AG879 impairs the in vitro replication of the peste des petits ruminants virus (PPRV). A reduced virus replication in Trk1-knockdown (siRNA) Vero cells confirmed the essential role of RTK in the virus replication, in particular a specific regulation of viral RNA synthesis. These data represent the first evidence that the RTK signaling regulates replication of a morbillivirus.

  14. Abl tyrosine kinases modulate cadherin-dependent adhesion upstream and downstream of Rho family GTPases.

    Science.gov (United States)

    Zandy, Nicole L; Pendergast, Ann Marie

    2008-02-15

    Formation and dissolution of intercellular adhesions are processes of paramount importance during tissue morphogenesis and for pathological conditions such as tumor metastasis. Cadherin-mediated intercellular adhesion requires dynamic regulation of the actin cytoskeleton. The pathways that link cadherin signaling to cytoskeletal regulation remain poorly defined. We have recently uncovered a novel role for the Abl family of tyrosine kinases linking cadherin-mediated adhesion to actin dynamics via the regulation of Rho family GTPases. Abl kinases are activated by cadherin engagement, localize to cell-cell junctions and are required for the formation of adherens junctions. Notably, we showed that Abl kinases are required for Rac activation during formation of adherens junctions, and also regulate a Rho-ROCK-myosin signaling pathway that is required for the maintenance of intercellular adhesion. Here we show that Abl kinases regulate the formation and strengthening of adherens junctions downstream of active Rac, and that Abl tyrosine kinases are components of a positive feed-back loop that employs the Crk/CrkL adaptor proteins to promote the formation and maturation of adherens junctions.

  15. Autoinhibition of Bruton's tyrosine kinase (Btk) and activation by soluble inositol hexakisphosphate

    Science.gov (United States)

    Wang, Qi; Vogan, Erik M; Nocka, Laura M; Rosen, Connor E; Zorn, Julie A; Harrison, Stephen C; Kuriyan, John

    2015-01-01

    Bruton's tyrosine kinase (Btk), a Tec-family tyrosine kinase, is essential for B-cell function. We present crystallographic and biochemical analyses of Btk, which together reveal molecular details of its autoinhibition and activation. Autoinhibited Btk adopts a compact conformation like that of inactive c-Src and c-Abl. A lipid-binding PH-TH module, unique to Tec kinases, acts in conjunction with the SH2 and SH3 domains to stabilize the inactive conformation. In addition to the expected activation of Btk by membranes containing phosphatidylinositol triphosphate (PIP3), we found that inositol hexakisphosphate (IP6), a soluble signaling molecule found in both animal and plant cells, also activates Btk. This activation is a consequence of a transient PH-TH dimerization induced by IP6, which promotes transphosphorylation of the kinase domains. Sequence comparisons with other Tec-family kinases suggest that activation by IP6 is unique to Btk. DOI: http://dx.doi.org/10.7554/eLife.06074.001 PMID:25699547

  16. Etk/Bmx tyrosine kinase activates Pak1 and regulates tumorigenicity of breast cancer cells.

    Science.gov (United States)

    Bagheri-Yarmand, R; Mandal, M; Taludker, A H; Wang, R A; Vadlamudi, R K; Kung, H J; Kumar, R

    2001-08-03

    Etk/Bmx, a member of the Tec family of nonreceptor protein-tyrosine kinases, is characterized by an N-terminal pleckstrin homology domain and has been shown to be a downstream effector of phosphatidylinositol 3-kinase. P21-activated kinase 1 (Pak1), another well characterized effector of phosphatidylinositol 3-kinase, has been implicated in the progression of breast cancer cells. In this study, we characterized the role of Etk in mammary development and tumorigenesis and explored the functional interactions between Etk and Pak1. We report that Etk expression is developmentally regulated in the mammary gland. Using transient transfection, coimmunoprecipitation and glutathione S-transferase-pull down assays, we showed that Etk directly associates with Pak1 via its N-terminal pleckstrin homology domain and also phosphorylates Pak1 on tyrosine residues. The expression of wild-type Etk in a non-invasive human breast cancer MCF-7 cells significantly increased proliferation and anchorage-independent growth of epithelial cancer cells. Conversely, expression of kinase-inactive mutant Etk-KQ suppressed the proliferation, anchorage-independent growth, and tumorigenicity of human breast cancer MDA-MB435 cells. These results indicate that Pak1 is a target of Etk and that Etk controls the proliferation as well as the anchorage-independent and tumorigenic growth of mammary epithelial cancer cells.

  17. Functions of the Lyn tyrosine kinase in health and disease

    Directory of Open Access Journals (Sweden)

    Ingley Evan

    2012-07-01

    Full Text Available Abstract Src family kinases such as Lyn are important signaling intermediaries, relaying and modulating different inputs to regulate various outputs, such as proliferation, differentiation, apoptosis, migration and metabolism. Intriguingly, Lyn can mediate both positive and negative signaling processes within the same or different cellular contexts. This duality is exemplified by the B-cell defect in Lyn−/− mice in which Lyn is essential for negative regulation of the B-cell receptor; conversely, B-cells expressing a dominant active mutant of Lyn (Lynup/up have elevated activities of positive regulators of the B-cell receptor due to this hyperactive kinase. Lyn has well-established functions in most haematopoietic cells, viz. progenitors via influencing c-kit signaling, through to mature cell receptor/integrin signaling, e.g. erythrocytes, platelets, mast cells and macrophages. Consequently, there is an important role for this kinase in regulating hematopoietic abnormalities. Lyn is an important regulator of autoimmune diseases such as asthma and psoriasis, due to its profound ability to influence immune cell signaling. Lyn has also been found to be important for maintaining the leukemic phenotype of many different liquid cancers including acute myeloid leukaemia (AML, chronic myeloid leukaemia (CML and B-cell lymphocytic leukaemia (BCLL. Lyn is also expressed in some solid tumors and here too it is establishing itself as a potential therapeutic target for prostate, glioblastoma, colon and more aggressive subtypes of breast cancer. Lay Abstract To relay information, a cell uses enzymes that put molecular markers on specific proteins so they interact with other proteins or move to specific parts of the cell to have particular functions. A protein called Lyn is one of these enzymes that regulate information transfer within cells to modulate cell growth, survival and movement. Depending on which type of cell and the source of the information

  18. Overexpression of the potential kinase serine/ threonine/tyrosine kinase 1 (STYK 1) in castration-resistant prostate cancer.

    Science.gov (United States)

    Chung, Suyoun; Tamura, Kenji; Furihata, Mutsuo; Uemura, Motohide; Daigo, Yataro; Nasu, Yasutomo; Miki, Tsuneharu; Shuin, Taro; Fujioka, Tomoaki; Nakamura, Yusuke; Nakagawa, Hidewaki

    2009-11-01

    Despite high response rates and clinical benefits, androgen ablation often fails to cure advanced or relapsed prostate cancer because castration-resistant prostate cancer (CRPC) cells inevitably emerge. CRPC cells not only grow under castration, but also behave more aggressively, indicating that a number of malignant signaling pathways are activated in CRPC cells as well as androgen receptor signaling. Based on information from the gene expression profiles of clinical CRPC cells, we here identified one overexpressed gene, serine/threonine/tyrosine kinase 1 (STYK1), encoding a potential kinase, as a molecular target for CRPC. RNA and immunohistochemical analyses validated the overexpression of STYK1 in prostate cancer cells, and its expression was distinct in CRPC cells. Knockdown of STYK1 by siRNA resulted in drastic suppression of prostate cancer cell growth and, concordantly, enforced expression of STYK1 promoted cell proliferation, whereas ectopic expression of a kinase-dead mutant STYK1 did not. An in vitro kinase assay using recombinant STYK1 demonstrated that STYK1 could have some potential as a kinase, although its specific substrates are unknown. These findings suggest that STYK1 could be a possible molecular target for CRPC, and small molecules specifically inhibiting STYK1 kinase could be a possible approach for the development of novel CRPC therapies.

  19. Structure-based drug design and AutoDock study of potential protein tyrosine kinase inhibitors.

    Science.gov (United States)

    Ali, Hamed Ismail; Nagamatsu, Tomofumi; Akaho, Eiichi

    2011-02-07

    Different classes of compounds were investigated for their binding affinities into different protein tyrosine kinases (PTKs) employing a novel flexible ligand docking approach by using AutoDock 3.05 and 4. These compounds include many flavin analogs, which were developed in our group with varying degrees of cytotoxic activity (comparable or moderately superior to cisplatin and ara-c), and database selected analogs. They were docked onto twelve different families of PTKs retrieved from the Protein Data Bank. These proteins are representatives of plausible models of interactions with chemotherapeutic agents. A comparative study of the intact co-crystallized ligands of various types of PTKs was carried out. Results revealed that the new class of 5-deazapteridine and steroid hybrid compounds VIa,b, and d, and the vertical-type bispyridodipyrimidine with n-hexyl chain junction between its N-10 and N-10 atoms Xa, exhibited non-selective PTK binding capacities, with the lowest (Gb). On the other hand, 2-amino benzoic acid analog IIa, phenoxypyrido [3, 4-d]pyrimidine derivative IVc, tyrosine containing tripeptide Vd, and the one from Sumisho data base 831 are proposed to have selective PTK binding affinities to certain classes of tyrosine kinases, namely, HGFR (c-met), ZAP-70, insulin receptor kinase, EGFR, respectively. All These compounds of highest affinities were docked within the binding sites of PTKs with reasonable RMSD and 1-5 hydrogen bonds.

  20. A promiscuous liaison between IL-15 receptor and Axl receptor tyrosine kinase in cell death control.

    Science.gov (United States)

    Budagian, Vadim; Bulanova, Elena; Orinska, Zane; Thon, Lutz; Mamat, Uwe; Bellosta, Paola; Basilico, Claudio; Adam, Dieter; Paus, Ralf; Bulfone-Paus, Silvia

    2005-12-21

    Discrimination between cytokine receptor and receptor tyrosine kinase (RTK) signaling pathways is a central paradigm in signal transduction research. Here, we report a 'promiscuous liaison' between both receptors that enables interleukin (IL)-15 to transactivate the signaling pathway of a tyrosine kinase. IL-15 protects murine L929 fibroblasts from tumor necrosis factor alpha (TNFalpha)-induced cell death, but fails to rescue them upon targeted depletion of the RTK, Axl; however, Axl-overexpressing fibroblasts are TNFalpha-resistant. IL-15Ralpha and Axl colocalize on the cell membrane and co-immunoprecipitate even in the absence of IL-15, whereby the extracellular part of Axl proved to be essential for Axl/IL-15Ralpha interaction. Most strikingly, IL-15 treatment mimics stimulation by the Axl ligand, Gas6, resulting in a rapid tyrosine phosphorylation of both Axl and IL-15Ralpha, and activation of the phosphatidylinositol 3-kinase/Akt pathway. This is also seen in mouse embryonic fibroblasts from wild-type but not Axl-/- or IL-15Ralpha-/- mice. Thus, IL-15-induced protection from TNFalpha-mediated cell death involves a hitherto unknown IL-15 receptor complex, consisting of IL-15Ralpha and Axl RTK, and requires their reciprocal activation initiated by ligand-induced IL-15Ralpha.

  1. 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.

  2. Treatment of Recurrent Intracranial Hemangiopericytoma with SRC-Related Tyrosine Kinase Targeted Therapy: A Case Report

    Directory of Open Access Journals (Sweden)

    Katherine B. Peters

    2010-04-01

    Full Text Available Hemangiopericytoma (HPC is a rare sarcomatous tumor arising from pericytes, a support cell found in blood vessels. These tumors can occur throughout the body, particularly in the lower extremities and retroperitoneum. In rare circumstances, HPCs can arise from the meninges. In these cases, they behave similar to meningiomas, in particular angiomatous meningiomas, but tend to be more aggressive and are likely to recur. Treatment usually focuses on surgical resection and radiotherapy with possible inclusion of chemotherapy for control of recurrent disease. We describe a case of recurrent right temporal HPC that first manifested as a paraneoplastic syndrome of oncogenic osteomalacia. Despite maximum therapy, this patient experienced multiple recurrences of the tumor, and immunohistochemical analysis revealed overexpression of platelet-derived growth factor receptor, a member of the SRC-related tyrosine kinases. After multiple recurrences, the patient’s tumor has been stable with treatment with monotherapy utilizing molecularly targeted therapy to SRC-related tyrosine kinases. This is the first case report of the treatment of recurrent meningeal HPC with molecularly targeted therapy to SRC-related tyrosine kinases.

  3. BMX tyrosine kinase gene is expressed in granulocytes and myeloid leukaemias.

    Science.gov (United States)

    Kaukonen, J; Lahtinen, I; Laine, S; Alitalo, K; Palotie, A

    1996-09-01

    The growth and maturation of haemopoietic cells is regulated by signal transduction through tyrosine protein kinases. Recently, a novel cytoplasmic tyrosine kinase gene in chromosome X, called Bmx, was identified in human bone marrow RNA. Bmx belongs to a subfamily of tyrosine kinases which are expressed in various haemopoietic cell lineages. We studied Bmx expression using RT-PCR of RNA from fractionated peripheral blood leucocytes, progenitor-enriched fractions of cord blood and from bone marrow or peripheral blood samples from leukaemia patients. Bmx was strongly expressed in haemopoietic tissues and enhanced in neutrophilic granulocytes. Bmx mRNA was also found in CD34-positive progenitor cells from cord blood. All samples (10/10) of patients with acute myeloid leukaemia and (4/4) with chronic myeloid leukaemia showed expression of Bmx. In contrast, none of the samples of acute lymphoid leukaemia (0/8) and only one out of six samples of chronic lymphoid leukaemia expressed Bmx. In conclusion, Bmx expression seems to be associated with myelopoiesis.

  4. Cloning of a novel phosphotyrosine binding domain containing molecule, Odin, involved in signaling by receptor tyrosine kinases

    DEFF Research Database (Denmark)

    Pandey, A.; Blagoev, B.; Kratchmarova, I.;

    2002-01-01

    We have used a proteomic approach using mass spectrometry to identify signaling molecules involved in receptor tyrosine kinase signaling pathways. Using affinity purification by anti-phosphotyrosine antibodies to enrich for tyrosine phosphorylated proteins, we have identified a novel signaling mo...

  5. MHC class I signaling in T cells leads to tyrosine kinase activity and PLC-gamma 1 phosphorylation

    DEFF Research Database (Denmark)

    Skov, S; Odum, Niels; Claesson, M H

    1995-01-01

    phosphorylation and the subsequent calcium response. The early tyrosine kinase activity was found to be dependent on expression of the TCR/CD3 complex and the CD45 molecule on the surface of the T cells. Furthermore, MHC-I cross-linking was shown to tyrosine phosphorylate PLC-gamma 1 (phospholipase C-gamma 1...

  6. A review of a novel, Bruton's tyrosine kinase inhibitor, ibrutinib.

    Science.gov (United States)

    Lee, Chung-Shien; Rattu, Mohammad A; Kim, Sara S

    2016-02-01

    Ibrutinib, a Bruton's kinase inhibitor, was granted an accelerated approval by the US Food and Drug Administration in November, 2013, for the treatment of relapsed or refractory mantle cell lymphoma and subsequently for the treatment of relapsed refractory chronic lymphocytic leukemia in February, 2014. In the pivotal phase 2 study of 111 patients with relapsed or refractory mantle cell lymphoma, the overall response rate in patients who received ibrutinib 560 mg daily was 68%. The median progression-free survival was 13.9 months, and the overall survival was 58% at 18 months. In a recently published phase 3 trial (RESONATE) that compared ibrutinib and ofatumumab for the treatment of relapsed and refractory chronic lymphocytic leukemia or small lymphocytic lymphoma, ibrutinib at the daily dosage of 420 mg demonstrated a significantly higher overall response rate (43% in ibrutinib vs. 4% in ofatumumab) and a significantly improved overall survival at 12 months (90% ibrutinib vs. 81% ofatumumab). Similar clinical benefits were shown regardless of del (17 p). Ibrutinib was well tolerated, and dose-limiting toxicity was not observed. Ibrutinib has shown durable remission, improved progression-free survival and overall survival, and favorable safety profile in indolent B-cell lymphoid malignancies. Ibrutinib, as a monotherapy, is an effective treatment modality as a salvage therapy for treatment of mantle cell lymphoma and chronic lymphocytic leukemia / small lymphocytic lymphoma, particularly in older patients (age ≥70 years) who are not a candidate for intensive chemotherapy and/or those with del (17 p). In patients with chronic lymphocytic leukemia and del (17 p), the current practice guideline recommends ibrutinib as an upfront treatment option. Current on-going trials will further define its role as upfront therapy and/or as a combination therapy in indolent B-cell lymphoid malignancies. © The Author(s) 2014.

  7. Role(s of IL-2 inducible T cell kinase and Bruton's tyrosine kinase in mast cell response to lipopolysaccharide

    Directory of Open Access Journals (Sweden)

    Weishan Huang

    2016-06-01

    Full Text Available Mast cells play critical roles during immune responses to the bacterial endotoxin lipopolysaccharide (LPS that can lead to fatal septic hypothermia [1–3]. IL-2 inducible T cell kinase (ITK and Bruton's tyrosine kinase (BTK are non-receptor tyrosine kinases that act downstream of numerous receptors, and have been shown to modulate mast cell responses downstream of FcεRIα [4], however, their roles in regulating mast cell responses to endotoxic stimuli were unclear. We found that the absence of ITK and BTK alters the mast cell response to LPS, and leads to enhanced pro-inflammatory cytokine production by mast cells and more severe LPS-induced hypothermia in mice [5]. Here, we detail our investigation using microarray analysis to study the transcriptomic profiles of mast cell responses to LPS, and the roles of ITK and/or BTK expression in this process. Mouse whole genome array data of WT, Itk−/−, Btk−/−, and Itk−/−Btk−/− bone marrow-derived mast cells (BMMCs stimulated by PBS (control or LPS for 1 h were used in our latest research article [5] and is available in the Gene Expression Omnibus under accession number GSE64287.

  8. Role(s) of IL-2 inducible T cell kinase and Bruton's tyrosine kinase in mast cell response to lipopolysaccharide.

    Science.gov (United States)

    Huang, Weishan; August, Avery

    2016-06-01

    Mast cells play critical roles during immune responses to the bacterial endotoxin lipopolysaccharide (LPS) that can lead to fatal septic hypothermia [1], [2], [3]. IL-2 inducible T cell kinase (ITK) and Bruton's tyrosine kinase (BTK) are non-receptor tyrosine kinases that act downstream of numerous receptors, and have been shown to modulate mast cell responses downstream of FcεRIα [4], however, their roles in regulating mast cell responses to endotoxic stimuli were unclear. We found that the absence of ITK and BTK alters the mast cell response to LPS, and leads to enhanced pro-inflammatory cytokine production by mast cells and more severe LPS-induced hypothermia in mice [5]. Here, we detail our investigation using microarray analysis to study the transcriptomic profiles of mast cell responses to LPS, and the roles of ITK and/or BTK expression in this process. Mouse whole genome array data of WT, Itk (-/-) , Btk (-/-) , and Itk (-/-)  Btk (-/-) bone marrow-derived mast cells (BMMCs) stimulated by PBS (control) or LPS for 1 h were used in our latest research article [5] and is available in the Gene Expression Omnibus under accession number GSE64287.

  9. Tyrosine phosphorylation of the BRI1 receptor kinase occurs via a posttranslational modification and is activated by the juxtamembrane domain

    Directory of Open Access Journals (Sweden)

    Man-Ho eOh

    2012-08-01

    Full Text Available In metazoans, receptor kinases control many essential processes related to growth and development and response to the environment. The receptor kinases in plants and animals are structurally similar but evolutionarily distinct and thus while most animal receptor kinases are tyrosine kinases the plant receptor kinases are classified as serine/threonine kinases. One of the best studied plant receptor kinases is BRASSINOSTEROID INSENSITIVE 1 (BRI1, which functions in brassinosteroid (BR signaling. Consistent with its classification, BRI1 was shown in early studies to autophosphorylate in vitro exclusively on serine and threonine residues and subsequently numerous specific phosphoserine and phosphothreonine sites were identified. However, several sites of tyrosine autophosphorylation have recently been identified establishing that BRI1 is a dual-specificity kinase. This raises the paradox that BRI1 contains phosphotyrosine but was only observed to autophosphorylate on serine and threonine sites. In the present study, we demonstrate that autophosphorylation on threonine and tyrosine (and presumably serine residues is a post-translational modification, ruling out a co-translational mechanism that could explain the paradox. Moreover, we show that in general, autophosphorylation of the recombinant protein appears to be hierarchal and proceeds in the order: phosphoserine > phosphothreonine > phosphotyrosine. This may explain why tyrosine autophosphorylation was not observed in some studies. Finally, we also show that the juxtamembrane domain of BRI1 is an activator of the kinase domain, and that kinase specificity (serine/threonine versus tyrosine can be affected by residues outside of the kinase domain. This may have implications for identification of signature motifs that distinguish serine/threonine kinases from dual-specificity kinases.

  10. NS-187 (INNO-406, a Bcr-Abl/Lyn Dual Tyrosine Kinase Inhibitor

    Directory of Open Access Journals (Sweden)

    Tomoko Niwa

    2007-01-01

    Full Text Available Protein kinases catalyze the transfer of the γ-phosphoryl group of adenosine triphosphate (ATP to the hydroxyl groups of protein side chains, and they play critical roles in regulating cellular signal transduction and other biochemical processes. They are attractive targets for today’s drug discovery and development, and many pharmaceutical companies are intensively developing various kinds of protein kinase inhibitors. A good example is the recent success with the Bcr-Abl tyrosine kinase inhibitor imatinib mesylate (GleevecTM in the treatment of chronic myeloid leukemia. Though imatinib has dramatically improved the treatment of Bcr-Abl-positive chronic myeloid leukemia, resistance is often found in patients with advanced-stage disease. Several mechanisms have been proposed to explain this resistance, including point mutations within the Abl kinase domain, amplification of the bcr-abl gene, overexpression of the corresponding mRNA, increased drug efflux mediated by P-glycoprotein, and activation of the Src-family kinase (SFK Lyn. We set out to develop a novel drug whose affinity for Abl is higher than that of imatinib and whose specifi city in inhibiting Lyn is higher than that of SFK/Abl inhibitors such as dasatinib (SprycelTM or bosutinib (SKI-606. Our work has led to the development of NS-187 (INNO-406, a novel Abl/Lyn dual tyrosine kinase inhibitor with clinical prospects. To provide an overview of how a selective kinase inhibitor has been developed, this review presents chemical-modification studies carried out with the guidance of molecular modeling, the structural basis for the high potency and selectivity of NS-187 based on the X-ray structure of the NS-187/Abl complex, and the biological profi ling of NS-187, including site-directed mutagenesis experiments.

  11. NPM-ALK: The Prototypic Member of a Family of Oncogenic Fusion Tyrosine Kinases

    Directory of Open Access Journals (Sweden)

    Joel D. Pearson

    2012-01-01

    Full Text Available Anaplastic lymphoma kinase (ALK was first identified in 1994 with the discovery that the gene encoding for this kinase was involved in the t(2;5(p23;q35 chromosomal translocation observed in a subset of anaplastic large cell lymphoma (ALCL. The NPM-ALK fusion protein generated by this translocation is a constitutively active tyrosine kinase, and much research has focused on characterizing the signalling pathways and cellular activities this oncoprotein regulates in ALCL. We now know about the existence of nearly 20 distinct ALK translocation partners, and the fusion proteins resulting from these translocations play a critical role in the pathogenesis of a variety of cancers including subsets of large B-cell lymphomas, nonsmall cell lung carcinomas, and inflammatory myofibroblastic tumours. Moreover, the inhibition of ALK has been shown to be an effective treatment strategy in some of these malignancies. In this paper we will highlight malignancies where ALK translocations have been identified and discuss why ALK fusion proteins are constitutively active tyrosine kinases. Finally, using ALCL as an example, we will examine three key signalling pathways activated by NPM-ALK that contribute to proliferation and survival in ALCL.

  12. Negative Regulation of Receptor Tyrosine Kinase (RTK Signaling: A Developing Field

    Directory of Open Access Journals (Sweden)

    Fernanda Ledda

    2007-01-01

    Full Text Available ophic factors control cellular physiology by activating specific receptor tyrosine kinases (RTKs. While the over activation of RTK signaling pathways is associated with cell growth and cancer, recent findings support the concept that impaired down-regulation or deactivation of RTKs may also be a mechanism involved in tumor formation. Under this perspective, the molecular determinants of RTK signaling inhibition may act as tumor-suppressor genes and have a potential role as tumor markers to monitor and predict disease progression. Here, we review the current understanding of the physiological mechanisms that attenuate RTK signaling and discuss evidence that implicates deregulation of these events in cancer.Abbreviations: BDP1: Brain-derived phosphatase 1; Cbl: Casitas B-lineage lymphoma; CIN-85: Cbl-interacting protein of 85 kDa; DER: Drosophila EGFR; EGFR: Epidermal growth factor receptor; ERK 1/2: Extracellular signal-regulated kinase 1/2; Grb2: Growth factor receptor-bound protein 2; HER2: Human epidermal growth factor receptor 2; LRIG: Leucine-rich repeats and immunoglobulin-like domain 1; MAPK: Mitogen-activated protein kinase; Mig 6: Mitogen-inducible gene 6; PTEN: Phosphatase and tensin homologue; RET: Rearranged in transformation; RTK: Receptor tyrosine kinase. SH2 domain: Src-homology 2 domain; SH3 domain: Src-homology 3 domain; Spry: Sprouty.

  13. TR-FRET binding assay targeting unactivated form of Bruton's tyrosine kinase.

    Science.gov (United States)

    Asami, Tokiko; Kawahata, Wataru; Sawa, Masaaki

    2015-01-01

    Bruton's Tyrosine Kinase (BTK) is one of the crucial kinases for the B cell maturation and mast cell activation, and specific inhibitors of BTK are considered to be attractive targets in drug discovery research. In this Letter, we have designed and synthesized a new fluorescent probe for TR-FRET-based high-throughput screening, to identify compounds that preferentially bind to an inactive conformation of BTK which has a unique structural feature. A set of kinase-focused compound library was screened using this assay method, and compound 31 was successfully identified as a potent inhibitor which preferentially bind to the inactive conformation of BTK. These results suggest that this screening method has a great potential for the discovery of novel selective BTK inhibitors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Spleen tyrosine kinase inhibitors for rheumatoid arthritis: where are we now?

    Science.gov (United States)

    Scott, Ian C; Scott, David L

    2014-03-01

    The development of small-molecule inhibitors of inflammatory cascade signaling kinases offers a potential approach to treating rheumatoid arthritis (RA). Spleen tyrosine kinase is one such tyrosine kinase. Recent research efforts have focussed on the development and testing of a spleen tyrosine kinase inhibitor, fostamatinib. We reviewed the results of the clinical trials of fostamatinib in RA with the aim of outlining its clinical efficacy and the nature and frequency of its main adverse events. To date, this drug has been evaluated in over 3,200 RA patients enrolled in three phase II, one phase IIb and three phase III trials. These studies showed fostamatinib was effective. In four trials in which patients received 100 mg twice daily, fostamatinib reduced inflammatory synovitis; the relative risks of achieving American College of Rheumatology Responder rates compared with placebo in the combined studies ranged from 1.6 for 20 % of responders to 3.7 for 70 % of responders. There was a similar relative risk of achieving a clinically meaningful reduction in disability of 1.6 for the chance of patients achieving a reduction in health assessment questionnaire scores of 0.22 or more. Three of the trials examined the impact of fostamatinib on erosive radiographic damage using changes in the modified total Sharp score. None of them provided any evidence for a significant effect of fostamatinib on erosive damage over 6 months. All the trials included descriptions of adverse events. Hypertension was common, involving over 40 % of patients treated. Other common adverse events included diarrhoea, neutropenia and increases in hepatic enzyme levels. Some patients developed infections. On the conclusion of the phase III trials, one of the main pharmaceutical sponsors decided not to further develop fostamatinib for RA.

  15. Bruton's tyrosine kinase (BTK) as a promising target in solid tumors.

    Science.gov (United States)

    Molina-Cerrillo, J; Alonso-Gordoa, T; Gajate, P; Grande, E

    2017-07-01

    Bruton's tyrosine kinase (BTK) is a non-receptor intracellular kinase that belongs to the TEC-family tyrosine kinases together with bone marrow-expressed kinase (BMX), redundant-resting lymphocyte kinase (RLK), and IL-2 inducible T-Cell kinase (ITK). All these proteins play a key role in the intracellular signaling of both B and T lymphocytes. Recently, some preclinical data have demonstrated that BTK is present in certain tumor subtypes and in other relevant cells that are contributing to the tumor microenvironment such as dendritic cells, macrophages, myeloid derived suppressor cells and endothelial cells. Ibrutinib (PCI-32765) is an orally available small molecule that acts as an inhibitor of the BTK and is approved for the treatment of patients with some hematological malignancies. It has been suggested that ibrutinib may also have a potential antitumor activity in solid neoplasms. In this sense, ibrutinib has the ability to revert polarization of TCD4+ to Th1 lymphocytes to increase the cytotoxic ability of T CD8+ and to regulate tumor-induced immune tolerance by acting over tumor infiltrating cells activity and immunosuppressive cytokines release. Furthermore, based on its molecular activity and safety, ibrutinib has been considered as a partner for treatment combination with PI3K/AKT/mTOR inhibitors or with immune-checkpoint inhibitors, inhibiting immunosuppressive signals from the tumor microenvironment, and overcoming the immune resistance to current anti-PD1/PDL1 immunotherapeutic drugs by the CXCR4/CXCL2 pathway regulation. Currently, a broad range of different studies are evaluating the activity of ibrutinib either as single agent or in combination in patients with solid tumors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Functional interaction between nonreceptor tyrosine kinase c-Abl and SR-Rich protein RBM39.

    Science.gov (United States)

    Mai, Sanyue; Qu, Xiuhua; Li, Ping; Ma, Qingjun; Liu, Xuan; Cao, Cheng

    2016-04-22

    RBM39, also known as splicing factor HCC1.4, acts as a transcriptional coactivator for the steroid nuclear receptors JUN/AP-1, ESR1/ER-α and ESR2/ER-β. RBM39 is involved in the regulation of the transcriptional responses of these steroid nuclear receptors and promotes transcriptional initiation. In this paper, we report that RBM39 interacts with the nonreceptor tyrosine kinase c-Abl. Both the Src homology (SH) 2 and SH3 domains of c-Abl interact with RBM39. The major tyrosine phosphorylation sites on RBM39 that are phosphorylated by c-Abl are Y95 and Y99, as demonstrated by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) and mutational analysis. c-Abl was shown boost the transcriptional coactivation activity of RBM39 for ERα and PRβ in a tyrosine kinase-dependent manner. The results suggest that mammalian c-Abl plays an important role in steroid hormone receptor-mediated transcription by regulating RBM39.

  17. Functional interaction between nonreceptor tyrosine kinase c-Abl and SR-Rich protein RBM39

    Energy Technology Data Exchange (ETDEWEB)

    Mai, Sanyue [Beijing Institute of Biotechnology, 27 Taiping Rd, Haidian District, Beijing 100850 (China); Qu, Xiuhua [General Navy Hospital of PLA, 6 Fucheng Rd, Haidian District, Beijing 100037 (China); Li, Ping; Ma, Qingjun [Beijing Institute of Biotechnology, 27 Taiping Rd, Haidian District, Beijing 100850 (China); Liu, Xuan, E-mail: liux931932@163.com [Beijing Institute of Biotechnology, 27 Taiping Rd, Haidian District, Beijing 100850 (China); Cao, Cheng, E-mail: cao_c@sohu.com [Beijing Institute of Biotechnology, 27 Taiping Rd, Haidian District, Beijing 100850 (China)

    2016-04-22

    RBM39, also known as splicing factor HCC1.4, acts as a transcriptional coactivator for the steroid nuclear receptors JUN/AP-1, ESR1/ER-α and ESR2/ER-β. RBM39 is involved in the regulation of the transcriptional responses of these steroid nuclear receptors and promotes transcriptional initiation. In this paper, we report that RBM39 interacts with the nonreceptor tyrosine kinase c-Abl. Both the Src homology (SH) 2 and SH3 domains of c-Abl interact with RBM39. The major tyrosine phosphorylation sites on RBM39 that are phosphorylated by c-Abl are Y95 and Y99, as demonstrated by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) and mutational analysis. c-Abl was shown boost the transcriptional coactivation activity of RBM39 for ERα and PRβ in a tyrosine kinase-dependent manner. The results suggest that mammalian c-Abl plays an important role in steroid hormone receptor-mediated transcription by regulating RBM39. - Highlights: • c-Abl interacts with RBM39. • RBM39 is phosphorylated by c-Abl. • c-Abl regulates transcriptional coactivation activity of RBM39 on the ERα and PRβ.

  18. Hierarchical Disabled-1 Tyrosine Phosphorylation in Src family Kinase Activation and Neurite Formation

    Science.gov (United States)

    Katyal, Sachin; Gao, Zhihua; Monckton, Elizabeth; Glubrecht, Darryl; Godbout, Roseline

    2013-01-01

    There are two developmentally regulated alternatively spliced forms of Disabled-1 (Dab1) in the chick retina: an early form (Dab1-E) expressed in retinal precursor cells and a late form (Dab1-L) expressed in neuronal cells. The main difference between these two isoforms is the absence of two Src family kinase (SFK) recognition sites in Dab1-E. Both forms retain two Abl/Crk/Nck recognition sites implicated in the recruitment of SH2 domain-containing signaling proteins. One of the Dab1-L-specific SFK recognition sites, at tyrosine(Y)-198, has been shown to be phosphorylated in Reelin-stimulated neurons. Here, we use Reelin-expressing primary retinal cultures to investigate the role of the four Dab1 tyrosine phosphorylation sites on overall tyrosine phosphorylation, Dab1 phosphorylation, SFK activation and neurite formation. We show that Y198 is essential but not sufficient for maximal Dab1 phosphorylation, SFK activation and neurite formation, with Y232 and Y220 playing particularly important roles in SFK activation and neuritogenesis, and Y185 having modifying effects secondary to Y232 and Y220. Our data support a role for all four Dab1 tyrosine phosphorylation sites in mediating the spectrum of activities associated with Reelin-Dab1 signaling in neurons. PMID:17350651

  19. SRC protein tyrosine kinase, c-Jun N-terminal kinase (JNK), and NF-kappaBp65 signaling in commercial and wild-type turkey leukocytes

    Science.gov (United States)

    Studies comparing signaling in wild-type turkey (WT) leukocytes and commercial turkey (CT) leukocytes found that the activity of protein tyrosine kinases (PTK) and MAP kinases, ERK 1/2 and p38, were significantly higher in WT leukocytes compared to CT lines upon exposure to both SE and OPSE on days...

  20. Autophosphorylation of the Bacterial Tyrosine-Kinase CpsD Connects Capsule Synthesis with the Cell Cycle in Streptococcus pneumoniae

    NARCIS (Netherlands)

    Nourikyan, Julien; Kjos, Morten; Mercy, Chryslène; Cluzel, Caroline; Morlot, Cécile; Noirot-Gros, Marie-Francoise; Guiral, Sébastien; Lavergne, Jean-Pierre; Veening, Jan-Willem; Grangeasse, Christophe

    2015-01-01

    Bacterial capsular polysaccharides (CPS) are produced by a multi-protein membrane complex, in which a particular type of tyrosine-autokinases named BY-kinases, regulate their polymerization and export. However, our understanding of the role of BY-kinases in these processes remains incomplete. In the

  1. Interleukin 7 receptor functions by recruiting the tyrosine kinase p59fyn through a segment of its cytoplasmic tail.

    OpenAIRE

    1992-01-01

    Engagement of the cell surface receptor for interleukin 7 (IL-7R) provokes protein tyrosine phosphorylation, although the receptor lacks a kinase catalytic domain in its cytoplasmic tail. The molecular basis of this response is not known. Here we report that the IL-7R functions by recruiting p59fyn, an intracellular tyrosine kinase of the src family. Treatment of pre-B cells with IL-7 causes an enhancement of the catalytic activity of p59fyn, but not of the related kinase p62yes. IL-7-depende...

  2. Multiple Functions of Let-23, a Caenorhabditis Elegans Receptor Tyrosine Kinase Gene Required for Vulval Induction

    Science.gov (United States)

    Aroian, R. V.; Sternberg, P. W.

    1991-01-01

    The let-23 gene, which encodes a putative tyrosine kinase of the epidermal growth factor (EGF) receptor subfamily, has multiple functions during Caenorhabditis elegans development. We show that let-23 function is required for vulval precursor cells (VPCs) to respond to the signal that induces vulval differentiation: a complete loss of let-23 function results in no induction. However, some let-23 mutations that genetically reduce but do not eliminate let-23 function result in VPCs apparently hypersensitive to inductive signal: as many as five of six VPCs can adopt vulval fates, in contrast to the three that normally do. These results suggest that the let-23 receptor tyrosine kinase controls two opposing pathways, one that stimulates vulval differentiation and another that negatively regulates vulval differentiation. Furthermore, analysis of 16 new let-23 mutations indicates that the let-23 kinase functions in at least five tissues. Since various let-23 mutant phenotypes can be obtained independently, the let-23 gene is likely to have tissue-specific functions. PMID:2071015

  3. Ibrutinib: a first in class covalent inhibitor of Bruton's tyrosine kinase.

    Science.gov (United States)

    Davids, Matthew S; Brown, Jennifer R

    2014-05-01

    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 variety of hematologic malignancies, most notably chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL), leading to US FDA approval for relapsed CLL and MCL. Ongoing studies are evaluating ibrutinib in other types of non-Hodgkin's lymphoma, such as diffuse large B-cell lymphoma and Waldenström's macrogobulinemia, in larger Phase III studies in CLL and MCL, and in combination studies with monoclonal antibodies and chemotherapy. Future studies will combine ibrutinib with other promising novel agents currently in development in hematologic malignancies.

  4. Ibrutinib: a first in class covalent inhibitor of Bruton’s tyrosine kinase

    Science.gov (United States)

    Davids, Matthew S; Brown, Jennifer R

    2015-01-01

    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 variety of hematologic malignancies, most notably chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL), leading to US FDA approval for relapsed CLL and MCL. Ongoing studies are evaluating ibrutinib in other types of non-Hodgkin’s lymphoma, such as diffuse large B-cell lymphoma and Waldenström’s macrogobulinemia, in larger Phase III studies in CLL and MCL, and in combination studies with monoclonal antibodies and chemotherapy. Future studies will combine ibrutinib with other promising novel agents currently in development in hematologic malignancies. PMID:24941982

  5. Clinical and scientific aspects of muscle-specific tyrosine kinase-related myasthenia gravis.

    Science.gov (United States)

    Reddel, Stephen W; Morsch, Marco; Phillips, William D

    2014-10-01

    Antibodies to muscle-specific tyrosine kinase (MuSK) characterize up to 5% of myasthenia gravis patients. This review focuses on the differences to clinical antiacetylcholine receptor-myasthenia gravis, and on the physiology and animal studies that elucidate the role of MuSK and help explain the clinical disease. MuSK forms the core of a protein complex in the postsynaptic membrane at the neuromuscular junction. During development, MuSK tyrosine kinase signaling is vital for the formation and stabilization of the postsynaptic endplate; it is now clear that long-term homeostasis of mature neuromuscular junctions requires MuSK function. Patient MuSK-antibodies are largely of the IgG4 type and in cell culture block the assembly and activation of MuSK kinase. Active immunization and passive transfer mouse models show reduced postsynaptic acetylcholine receptors and disturbed synaptic alignment, diminished synaptic potentials and impaired muscle activation.MuSK myasthenia gravis patients display particular bulbar and respiratory muscle involvement, with a high rate of myasthenic crises. Plasma exchange and immunosuppression with corticosteroids and rituximab appear to be most effective in treating MuSK myasthenia gravis. In contrast, the cholinesterase inhibitors, such as pyridostigmine, appear less suitable for this form of myasthenia gravis. MuSK myasthenia gravis has distinct clinical and pathophysiological features.

  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. Oncogenic signaling by Kit tyrosine kinase occurs selectively on the Golgi apparatus in gastrointestinal stromal tumors.

    Science.gov (United States)

    Obata, Y; Horikawa, K; Takahashi, T; Akieda, Y; Tsujimoto, M; Fletcher, J A; Esumi, H; Nishida, T; Abe, R

    2017-02-13

    Gastrointestinal stromal tumors (GISTs) are caused by gain-of-function mutations in the Kit receptor tyrosine kinase. Most primary GIST patients respond to the Kit inhibitor imatinib, but this drug often becomes ineffective because of secondary mutations in the Kit kinase domain. The characteristic intracellular accumulation of imatinib-sensitive and -resistant Kit protein is well documented, but its relationship to oncogenic signaling remains unknown. Here, we show that in cancer tissue from primary GIST patients as well as in cell lines, mutant Kit accumulates on the Golgi apparatus, whereas normal Kit localizes to the plasma membrane (PM). In imatinib-resistant GIST with a secondary Kit mutation, Kit localizes predominantly on the Golgi apparatus. Both imatinib-sensitive and imatinib-resistant Kit (Kit(mut)) become fully auto-phosphorylated only on the Golgi and only if in a complex-glycosylated form. Kit(mut) accumulates on the Golgi during the early secretory pathway, but not after endocytosis. The aberrant kinase activity of Kit(mut) prevents its export from the Golgi to the PM. Furthermore, Kit(mut) on the Golgi signals and activates the phosphatidylinositol 3-kinase-Akt (PI3K-Akt) pathway, signal transducer and activator of transcription 5 (STAT5), and the Mek-Erk pathway. Blocking the biosynthetic transport of Kit(mut) to the Golgi from the endoplasmic reticulum inhibits oncogenic signaling. PM localization of Kit(mut) is not required for its signaling. Activation of Src-family tyrosine kinases on the Golgi is essential for oncogenic Kit signaling. These results suggest that the Golgi apparatus serves as a platform for oncogenic Kit signaling. Our study demonstrates that Kit(mut)'s pathogenicity is related to its mis-localization, and may offer a new strategy for treating imatinib-resistant GISTs.Oncogene advance online publication, 13 February 2017; doi:10.1038/onc.2016.519.

  8. 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.

  9. Complement receptor-3 negatively regulates the phagocytosis of degenerated myelin through tyrosine kinase Syk and cofilin

    Directory of Open Access Journals (Sweden)

    Hadas Smadar

    2012-07-01

    Full Text Available Abstract Background Intact myelin, which normally surrounds axons, breaks down in Wallerian degeneration following axonal injury and during neurodegenerative diseases such as multiple sclerosis. Clearance of degenerated myelin by phagocytosis is essential since myelin impedes repair and exacerbates damage. CR3 (complement receptor-3 is a principal phagocytic receptor in myelin phagocytosis. We studied how tyrosine kinase Syk (spleen tyrosine kinase and cofilin control phagocytosis of degenerated myelin by CR3 in microglia and macrophages. Syk is a non-receptor tyrosine kinase that CR3 recruits to convey cellular functions. Cofilin is an actin-depolymerizing protein that controls F-actin (filamentous actin remodeling (i.e., disassembly and reassembly by shifting between active unphosphorylated and inactive phosphorylated states. Results Syk was continuously activated during prolonged phagocytosis. Phagocytosis increased when Syk activity and expression were reduced, suggesting that normally Syk down regulates CR3-mediated myelin phagocytosis. Levels of inactive p-cofilin (phosphorylated cofilin decreased transiently during prolonged phagocytosis. In contrast, p-cofilin levels decreased continuously when Syk activity and expression were continuously reduced, suggesting that normally Syk advances the inactive state of cofilin. Observations also revealed inverse relationships between levels of phagocytosis and levels of inactive p-cofilin, suggesting that active unphosphorylated cofilin advances phagocytosis. Active cofilin could advance phagocytosis by promoting F-actin remodeling, which supports the production of membrane protrusions (e.g., filopodia, which, as we also revealed, are instrumental in myelin phagocytosis. Conclusions CR3 both activates and downregulates myelin phagocytosis at the same time. Activation was previously documented. We presently demonstrate that downregulation is mediated through Syk, which advances the inactive

  10. Identification Of Akn-032, A Novel 2-Aminopyrazine Tyrosine Kinase Inhibitor, With Significant Preclinical Activity In Acute Myeloid Leukemia

    OpenAIRE

    Eriksson, Anna; Höglund, Martin; Lindhagen, Elin; Åleskog, Anna; Hassan, Sadia Bashir; Ekholm, Carina; Fhölenhag, Karin; Jensen, Annika Jenmalm; Löthgren, Agneta; Scobie, Martin; Larsson, Rolf; Parrow, Vendela

    2010-01-01

    Abstract Aberrant signal transduction by mutant or overexpressed protein kinases has emerged as a promising target for treatment of acute myeloid leukemia (AML). We here present a novel low molecular weight kinase inhibitor, AKN-032, targeting the FMS-like tyrosine kinase 3 (FLT3) and discovered in a new type of screening funnel combining the target therapy approach with sequential cellular screens. AKN-032 was identified among 150 selected hits from three different high throughput...

  11. A Src-like inactive conformation in the abl tyrosine kinase domain.

    Directory of Open Access Journals (Sweden)

    Nicholas M Levinson

    2006-05-01

    Full Text Available The improper activation of the Abl tyrosine kinase results in chronic myeloid leukemia (CML. The recognition of an inactive conformation of Abl, in which a catalytically important Asp-Phe-Gly (DFG motif is flipped by approximately 180 degrees with respect to the active conformation, underlies the specificity of the cancer drug imatinib, which is used to treat CML. The DFG motif is not flipped in crystal structures of inactive forms of the closely related Src kinases, and imatinib does not inhibit c-Src. We present a structure of the kinase domain of Abl, determined in complex with an ATP-peptide conjugate, in which the protein adopts an inactive conformation that resembles closely that of the Src kinases. An interesting aspect of the Src-like inactive structure, suggested by molecular dynamics simulations and additional crystal structures, is the presence of features that might facilitate the flip of the DFG motif by providing room for the phenylalanine to move and by coordinating the aspartate side chain as it leaves the active site. One class of mutations in BCR-Abl that confers resistance to imatinib appears more likely to destabilize the inactive Src-like conformation than the active or imatinib-bound conformations. Our results suggest that interconversion between distinctly different inactive conformations is a characteristic feature of the Abl kinase domain.

  12. Receptor Tyrosine Kinase EphB4 Is a Survival Factor in Breast Cancer

    OpenAIRE

    Kumar, S. Ram; Singh, Jasbir; Xia, Guangbin; Krasnoperov, Valery; Hassanieh, Loubna; Ley, Eric J.; Scehnet, Jeffrey; Kumar, Neil G.; Hawes, Debra; Press, Michael F.; Weaver, Fred A.; Gill, Parkash S.

    2006-01-01

    EphB4, a member of the largest family of receptor tyrosine kinases, is normally expressed on endothelial and neuronal cells. Although aberrant expression of EphB4 has been reported in several human tumors, including breast cancer, its functional significance is not understood. We report here that EphB4 is expressed in 7 of 12 (58%) human breast cancer specimens and 4 of 4 (100%) breast tumor cell lines examined. Overexpression of EphB4 in breast cancer cells was driven by gene amplification a...

  13. Pregnancies in patients with chronic myeloid leukemia treated with tyrosine kinase inhibitor.

    Science.gov (United States)

    Zhou, Li; You, Jian-Hua; Wu, Wen; Li, Jun-Min; Shen, Zhi-Xiang; Wang, Ai-Hua

    2013-10-01

    We presented our experience in chronic myeloid leukemia (CML) patients who conceived children and/or became pregnant while receiving tyrosine kinase inhibitor (TKI). Among 7 male patients, 7 pregnancies resulted in the birth of 7 healthy babies. Among 18 female patients, 8 ended in elective abortion; 3 had spontaneous abortion, and 7 carried to term, resulting in the birth of 8 healthy babies. All children have normal growth and development. All patients remain in TKI therapy and in good response. It is suggested that female patients are advised to practice adequate contraception. No special precautions apply for male patients receiving TKI.

  14. Single cell imaging of Bruton's Tyrosine Kinase using an irreversible inhibitor

    Science.gov (United States)

    Turetsky, Anna; Kim, Eunha; Kohler, Rainer H.; Miller, Miles A.; Weissleder, Ralph

    2014-04-01

    A number of Bruton's tyrosine kinase (BTK) inhibitors are currently in development, yet it has been difficult to visualize BTK expression and pharmacological inhibition in vivo in real time. We synthesized a fluorescent, irreversible BTK binder based on the drug Ibrutinib and characterized its behavior in cells and in vivo. We show a 200 nM affinity of the imaging agent, high selectivity, and irreversible binding to its target following initial washout, resulting in surprisingly high target-to-background ratios. In vivo, the imaging agent rapidly distributed to BTK expressing tumor cells, but also to BTK-positive tumor-associated host cells.

  15. A novel 2,5-diaminopyrimidine-based affinity probe for Bruton’s tyrosine kinase

    Science.gov (United States)

    Zuo, Yingying; Shi, Yanxia; Li, Xitao; Teng, Yingqi; Pan, Zhengying

    2015-11-01

    As a critical regulator of the B-cell receptor signaling pathway, Bruton’s tyrosine kinase (Btk) has attracted intensive drug discovery efforts for treating B-cell lineage cancers and autoimmune disorders. In particular, covalent inhibitors targeting Cys481 in Btk have demonstrated impressive clinical benefits, and their companion affinity probes have been crucial in the drug development process. Recently, we have discovered a novel series of 2,5-diaminopyrimidine-based covalent irreversible inhibitors of Btk. Here, we present the discovery of a novel affinity Btk probe based on the aforementioned scaffold and demonstrate its usage in evaluating the target engagement of Btk inhibitors in live cells.

  16. Bruton's tyrosine kinase (Btk) inhibitor ibrutinib suppresses stem-like traits in ovarian cancer.

    Science.gov (United States)

    Zucha, Muhammad Ary; Wu, Alexander T H; Lee, Wei-Hwa; Wang, Liang-Shun; Lin, Wan-Wan; Yuan, Chiou-Chung; Yeh, Chi-Tai

    2015-05-30

    According to a Prognoscan database, upregulation of Bruton's tyrosine kinase (Btk) is associated with low overall survival in ovarian cancer patients. We found that spheroids-forming ovarian cancer cell, which highly expressed cancer stem-like cell (CSC) markers and Btk, were cisplatin resistant. We next treated CSCs and non-CSCs by a combination of ibrutinib and cisplatin. We found that chemoresistance was dependent on Btk and JAK2/STAT3, which maintained CSC by inducing Sox-2 and prosurvival genes. We suggest that addition of ibrutinib to cisplatin may improve treatment outcome in ovarian cancer.

  17. A novel 2,5-diaminopyrimidine-based affinity probe for Bruton's tyrosine kinase.

    Science.gov (United States)

    Zuo, Yingying; Shi, Yanxia; Li, Xitao; Teng, Yingqi; Pan, Zhengying

    2015-11-04

    As a critical regulator of the B-cell receptor signaling pathway, Bruton's tyrosine kinase (Btk) has attracted intensive drug discovery efforts for treating B-cell lineage cancers and autoimmune disorders. In particular, covalent inhibitors targeting Cys481 in Btk have demonstrated impressive clinical benefits, and their companion affinity probes have been crucial in the drug development process. Recently, we have discovered a novel series of 2,5-diaminopyrimidine-based covalent irreversible inhibitors of Btk. Here, we present the discovery of a novel affinity Btk probe based on the aforementioned scaffold and demonstrate its usage in evaluating the target engagement of Btk inhibitors in live cells.

  18. Fragment-Based Discovery of a Small Molecule Inhibitor of Bruton's Tyrosine Kinase.

    Science.gov (United States)

    Smith, Christopher R; Dougan, Douglas R; Komandla, Mallareddy; Kanouni, Toufike; Knight, Beverly; Lawson, J David; Sabat, Mark; Taylor, Ewan R; Vu, Phong; Wyrick, Corey

    2015-07-23

    The discovery and optimization of a series of 4-aminocinnoline-3-carboxamide inhibitors of Bruton's tyrosine kinase are reported. A fragment-based screening approach incorporating X-ray co-crystallography was used to identify a cinnoline fragment and characterize its binding mode in the ATP binding site of Btk. Optimization of the fragment hit resulted in the identification of a lead compound which reduced paw swelling in a dose- and exposure-dependent fashion in a rat model of collagen-induced arthritis.

  19. Correction: Bruton's tyrosine kinase inhibitors in chronic lymphocytic leukemia and lymphoma.

    Science.gov (United States)

    2016-09-01

    An article in the July 2016 issue, "Bruton's tyrosine kinase inhibitors in chronic lymphocytic leukemia and lymphoma" by Gaurav Varma, MSPH, Tyler P. Johnson, MD, and Ranjana H. Advani, MD, described ONO/GS-4059 as a "reversible" inhibitor of BTK when it is in fact an "irreversible" inhibitor. We have made the correction to pages 546 and 552 of the online version at www.hematologyandoncology.net. Many thanks to an astute reader for pointing out the error. This corrects the article pmid:27379948.

  20. Endocrine side-effects of anti-cancer drugs: thyroid effects of tyrosine kinase inhibitors.

    Science.gov (United States)

    Illouz, Frédéric; Braun, Doreen; Briet, Claire; Schweizer, Ulrich; Rodien, Patrice

    2014-09-01

    Tyrosine kinase inhibitors (TKIs) are currently used by most oncologists. Among their side effects, thyroid dysfunctions are nowadays clearly observed. Whereas changes in thyroid function tests have been originally described with sunitinib, we now know that many TKIs can induce hypothyroidism and hyperthyroidism. In this study, the various molecules implicated in thyroid dysfunctions are analysed and the latest data on physiopathological mechanisms are approached in order to propose a strategy of thyroid monitoring of patients on TKI therapy. © 2014 European Society of Endocrinology.

  1. Efficacy of HER2-targeted therapy in metastatic breast cancer. Monoclonal antibodies and tyrosine kinase inhibitors

    DEFF Research Database (Denmark)

    Nielsen, Dorte L; Kümler, Iben; Palshof, Jesper Andreas;

    2013-01-01

    Therapies targeting the human epidermal growth factor receptor (HER) 2 are effective in metastatic breast cancer (MBC). We review the efficacy of HER2-directed therapies, focussing on monoclonal antibodies and tyrosine kinase inhibitors targeting HER2 that have been tested in phase II-III studies...... to those obtained for capecitabine plus lapatinib (48%), continuing trastuzumab in combination with capecitabine (48%), pertuzumab plus trastuzumab (24%), and neratinib (24%). Strategies combining multiple HER2-directed therapies might yield additive or synergistic effects and lead to improved outcome...

  2. 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.

  3. Role of tyrosine-kinase inhibitors in myeloproliferative neoplasms: comparative lessons learned

    Directory of Open Access Journals (Sweden)

    Pinilla-Ibarz J

    2016-08-01

    Full Text Available Javier Pinilla-Ibarz, Kendra L Sweet, Gabriela M Corrales-Yepez, Rami S Komrokji Department of Malignant Hematology, H Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA Abstract: An important pathogenetic distinction in the classification of myeloproliferative neoplasms (MPNs is the presence or absence of the BCR–ABL fusion gene, which encodes a unique oncogenic tyrosine kinase. The BCR–ABL fusion, caused by the formation of the Philadelphia chromosome (Ph through translocation, constitutes the disease-initiating event in chronic myeloid leukemia. The development of successive BCR–ABL-targeted tyrosine-kinase inhibitors has led to greatly improved outcomes in patients with chronic myeloid leukemia, including high rates of complete hematologic, cytogenetic, and molecular responses. Such levels of treatment success have long been elusive for patients with Ph-negative MPNs, because of the difficulties in identifying specific driver proteins suitable as drug targets. However, in recent years an improved understanding of the complex pathobiology of classic Ph-negative MPNs, characterized by variable, overlapping multimutation profiles, has prompted the development of better and more broadly targeted (to pathway rather than protein treatment options, particularly JAK inhibitors. In classic Ph-negative MPNs, overactivation of JAK-dependent signaling pathways is a central pathogenic mechanism, and mutually exclusive mutations in JAK2, MPL, and CALR linked to aberrant JAK activation are now recognized as key drivers of disease progression in myelofibrosis (MF. In clinical trials, the JAK1/JAK2 inhibitor ruxolitinib – the first therapy approved for MF worldwide – improved disease-related splenomegaly and symptoms independent of JAK2V617F mutational status, and prolonged survival compared with placebo or standard therapy in patients with advanced MF. In separate trials, ruxolitinib also provided comprehensive hematologic control in

  4. The Receptor Tyrosine Kinase Mertk Regulates Dendritic Cell Production of BAFF

    OpenAIRE

    Gohlke, P.R.; Williams, J. C.; Vilen, B J; Dillon, S.R.; Tisch, R; Matsushima, G.K.

    2009-01-01

    The MerTK receptor tyrosine kinase is an important negative regulator of dendritic cell function and is required to prevent B cell autoimmunity in vivo. It is not currently known however, if any causal relationship exists between these two aspects of MerTK function. We sought to determine if dendritic cells from mice lacking MerTK (mertk−/− mice) have characteristics that may aid in the development of B cell autoimmunity. Specifically, we found that mertk−/− mice contain an elevated number of...

  5. Stimulation of receptor-associated kinase, tyrosine kinase, and MAP kinase is required for prolactin-mediated macromolecular biosynthesis and mitogenesis in Nb2 lymphoma.

    Science.gov (United States)

    Carey, G B; Liberti, J P

    1995-01-10

    Lactogens [prolactin (Prl) and growth hormone] stimulate phosphorylation of the 40S ribosomal protein, S6, in Nb2 cells by mechanisms that do not involve participation of cAMP or protein kinase A, protein kinase C, or cGMP-dependent protein kinase. However, inhibition of tyrosine kinase (TK) abrogates Prl-mediated macromolecular biosynthesis. Inasmuch as lactogen signaling may involve sequential activation of protein kinases, the effect of Prl on the well-characterized mitogen-activated protein kinase (MAPK) and S6 kinase (S6K), the enzyme responsible for S6 phosphorylation in vivo, and their relationship to Nb2 macromolecular biosynthesis and mitogenesis were investigated. The results show that MAPK stimulation is transient (peak activity, 30 min) and precedes that of S6K, which reaches a maximum at 1.5-2 h, and slowly returns towards control levels at 6 h. Both staurosporine which inhibits GH receptor-associated kinase (JAK2) and genistein (GEN), an inhibitor of membrane-associated and cytoplasmic TKs, abrogate Prl-stimulated TK, MAPK, and S6K. Rapamycin (RAP), a specific inhibitor of p70S6K, completely blocks S6K but does not affect TK and MAPK. TK and MAPK activity correlates with Prl-stimulated anabolism, i.e., protein and DNA synthesis and mitogenesis. Thus, concentrations of STR and GEN which abrogate TK and MAPK inhibit anabolism virtually 100%. However, RAP, which inhibits S6K (ca. 100%) but not TK or MAPK, only delays Prl-mediated anabolism. These results indicate that Prl signaling in Nb2 cells involves a protein kinase cascade and that regulation of receptor-associated kinase, TK, and MAPK correlates with anabolism. The role of S6K (and S6 phosphorylation) appears to be ancillary.

  6. The insect neuropeptide PTTH activates receptor tyrosine kinase torso to initiate metamorphosis.

    Science.gov (United States)

    Rewitz, Kim F; Yamanaka, Naoki; Gilbert, Lawrence I; O'Connor, Michael B

    2009-12-04

    Holometabolous insects undergo complete metamorphosis to become sexually mature adults. Metamorphosis is initiated by brain-derived prothoracicotropic hormone (PTTH), which stimulates the production of the molting hormone ecdysone via an incompletely defined signaling pathway. Here we demonstrate 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 in the prothoracic gland (PG), and its loss phenocopies the removal of PTTH. The activation of Torso by PTTH stimulates extracellular signal-regulated kinase (ERK) phosphorylation, and the loss of ERK in the PG phenocopies the loss of PTTH and Torso. We conclude that PTTH initiates metamorphosis by activation of the Torso/ERK pathway.

  7. 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.

  8. Clinical pharmacology of tyrosine kinase inhibitors becoming generic drugs: the regulatory perspective.

    Science.gov (United States)

    Eckstein, Niels; Röper, Lea; Haas, Bodo; Potthast, Henrike; Hermes, Ulrike; Unkrig, Christoph; Naumann-Winter, Frauke; Enzmann, Harald

    2014-02-07

    Over the last decades, billions have been spent and huge efforts have been taken in basic and clinical cancer research [CA Cancer J Clin63:11-30]. About a decade ago, the arms race between drugs and cancer cells reached a new level by introduction of tyrosine kinase inhibitors (TKI) into pharmacological anti-cancer therapy. According to their molecular mechanism of action, TKI in contrast to so-called "classic" or "conventional" cytostatics belong to the group of targeted cancer medicines, characterized by accurately fitting with biological structures (i.e. active centers of kinases). Numerous (partly orphan) indications are covered by this new class of substances. Approximately ten years after the first substances of this class of medicines were authorized, patent protection will end within the next years. The following article covers clinical meaning and regulatory status of anti-cancer TKI and gives an outlook to what is expected from the introduction of generic anti-cancer TKI.

  9. PCI-32765, the First BTK (Bruton’s Tyrosine Kinase) Inhibitor in Clinical Trials

    Science.gov (United States)

    2013-01-01

    Ibrutinib is a potent covalent kinase inhibitor that targets BTK. BTK, or Bruton’s tyrosine kinase, is an obvious target for therapy of B cell diseases because inactivating mutations lead to B cell aplasia in humans and the disease X-linked agammaglobulinemia. Ibrutinib has modest cytotoxicity against CLL cells in vitro but also blocks trophic stimuli from the microenvironment. As with other inhibitors of the BCR pathway, ibrutinib causes rapid nodal reduction and response associated with rapid increase in lymphocytosis, which then returns to baseline over time. The ORR of ibrutinib in relapsed refractory CLL is 67 % with PFS 88 % at 15 months. In a cohort of untreated patients 65 years and over, the estimated 15 month PFS is 96 %. Registration trials have been initiated, and the difficult task that remains is to determine where in the course of CLL therapy this drug will have the greatest impact and benefit for patients. PMID:23296407

  10. Reduced Proteolytic Shedding of Receptor Tyrosine Kinases is a Post-Translational Mechanism of Kinase Inhibitor Resistance

    Science.gov (United States)

    Miller, Miles A.; Oudin, Madeleine J.; Sullivan, Ryan J.; Wang, Stephanie J.; Meyer, Aaron S.; Im, Hyungsoon; Frederick, Dennie T.; Tadros, Jenny; Griffith, Linda G.; Lee, Hakho; Weissleder, Ralph; Flaherty, Keith T.; Gertler, Frank B.; Lauffenburger, Douglas A.

    2016-01-01

    Kinase inhibitor resistance often involves upregulation of poorly understood “bypass” signaling pathways. Here, we show that extracellular proteomic adaptation is one path to bypass signaling and drug resistance. Proteolytic shedding of surface receptors, which can provide negative feedback on signaling activity, is blocked by kinase inhibitor treatment and enhances bypass signaling. In particular, MEK inhibition broadly decreases shedding of multiple receptor tyrosine kinases (RTKs) including HER4, MET, and most prominently AXL, an ADAM10 and ADAM17 substrate, thus increasing surface RTK levels and mitogenic signaling. Progression-free survival of melanoma patients treated with clinical BRAF/MEK inhibitors inversely correlates with RTK shedding reduction following treatment, as measured non-invasively in blood plasma. Disrupting protease inhibition by neutralizing TIMP1 improves MAPK inhibitor efficacy, and combined MAPK/AXL inhibition synergistically reduces tumor growth and metastasis in xenograft models. Altogether, extracellular proteomic rewiring through reduced RTK shedding represents a surprising mechanism for bypass signaling in cancer drug resistance. PMID:26984351

  11. The tyrosine kinase BMX is an essential mediator of inflammatory arthritis in a kinase-independent manner.

    Science.gov (United States)

    Gottar-Guillier, Marie; Dodeller, Francis; Huesken, Dieter; Iourgenko, Vadim; Mickanin, Craig; Labow, Mark; Gaveriaux, Samuel; Kinzel, Bernd; Mueller, Matthias; Alitalo, Kari; Littlewood-Evans, Amanda; Cenni, Bruno

    2011-05-15

    Inflammatory cytokines like TNF play a central role in autoimmune disorders such as rheumatoid arthritis. We identified the tyrosine kinase bone marrow kinase on chromosome X (BMX) as an essential component of a shared inflammatory signaling pathway. Transient depletion of BMX strongly reduced secretion of IL-8 in cell lines and primary human cells stimulated by TNF, IL-1β, or TLR agonists. BMX was required for phosphorylation of p38 MAPK and JNK, as well as activation of NF-κB. The following epistasis analysis indicated that BMX acts downstream of or at the same level as the complex TGF-β activated kinase 1 (TAK1)-TAK1 binding protein. At the cellular level, regulation of the IL-8 promoter required the pleckstrin homology domain of BMX, which could be replaced by an ectopic myristylation signal, indicating a requirement for BMX membrane association. In addition, activation of the IL-8 promoter by in vitro BMX overexpression required its catalytic activity. Genetic ablation of BMX conferred protection in the mouse arthritis model of passive K/BxN serum transfer, confirming that BMX is an essential mediator of inflammation in vivo. However, genetic replacement with a catalytically inactive BMX allele was not protective in the same arthritis animal model. We conclude that BMX is an essential component of inflammatory cytokine signaling and that catalytic, as well as noncatalytic functions of BMX are involved.

  12. 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.

  13. Activation of nonreceptor tyrosine kinase Bmx/Etk mediated by phosphoinositide 3-kinase, epidermal growth factor receptor, and ErbB3 in prostate cancer cells.

    Science.gov (United States)

    Jiang, Xinnong; Borgesi, Robert A; McKnight, Nicole C; Kaur, Ramneet; Carpenter, Christopher L; Balk, Steven P

    2007-11-09

    Pathways activated downstream of constitutively active phosphatidylinositol (PI) 3-kinase in PTEN-deficient prostate cancer (PCa) cells are possible therapeutic targets. We found that the nonreceptor Tec family tyrosine kinase Bmx/Etk was activated by tyrosine phosphorylation downstream of Src and PI 3-kinase in PTEN-deficient LNCaP and PC3 PCa cells and that Bmx down-regulation by short interfering RNA markedly inhibited LNCaP cell growth. Bmx also associated with ErbB3 in LNCaP cells, and heregulin-beta1 enhanced this interaction and further stimulated Bmx activity. Epidermal growth factor (EGF) similarly stimulated an interaction between Bmx and EGF receptor and rapidly increased Bmx kinase activity. Bmx stimulation in response to heregulin-beta1 and EGF was Src-dependent, and heregulin-beta1 stimulation of Bmx was also PI 3-kinase-dependent. In contrast, the rapid tyrosine phosphorylation and activation of Bmx in response to EGF was PI 3-kinase-independent. Taken together, these results demonstrate that Bmx is a critical downstream target of the constitutively active PI 3-kinase in PTEN-deficient PCa cells and further show that Bmx is recruited by the EGF receptor and ErbB3 and activated in response to their respective ligands. Therefore, Bmx may be a valuable therapeutic target in PCa and other epithelial malignancies in which PI 3-kinase or EGF receptor family pathways are activated.

  14. Haemophilus ducreyi targets Src family protein tyrosine kinases to inhibit phagocytic signaling.

    Science.gov (United States)

    Mock, Jason R; Vakevainen, Merja; Deng, Kaiping; Latimer, Jo L; Young, Jennifer A; van Oers, Nicolai S C; Greenberg, Steven; Hansen, Eric J

    2005-12-01

    Haemophilus ducreyi, the etiologic agent of the sexually transmitted disease chancroid, has been shown to inhibit phagocytosis of both itself and secondary targets in vitro. Immunodepletion of LspA proteins from H. ducreyi culture supernatant fluid abolished this inhibitory effect, indicating that the LspA proteins are necessary for the inhibition of phagocytosis by H. ducreyi. Fluorescence microscopy revealed that macrophages incubated with wild-type H. ducreyi, but not with a lspA1 lspA2 mutant, were unable to complete development of the phagocytic cup around immunoglobulin G-opsonized targets. Examination of the phosphotyrosine protein profiles of these two sets of macrophages showed that those incubated with wild-type H. ducreyi had greatly reduced phosphorylation levels of proteins in the 50-to-60-kDa range. Subsequent experiments revealed reductions in the catalytic activities of both Lyn and Hck, two members of the Src family of protein tyrosine kinases that are known to be involved in the proximal signaling steps of Fcgamma receptor-mediated phagocytosis. Additional experiments confirmed reductions in the levels of both active Lyn and active Hck in three different immune cell lines, but not in HeLa cells, exposed to wild-type H. ducreyi. This is the first example of a bacterial pathogen that suppresses Src family protein tyrosine kinase activity to subvert phagocytic signaling in hostcells.

  15. Dynamics of the Tec-family tyrosine kinase SH3 domains.

    Science.gov (United States)

    Roberts, Justin M; Tarafdar, Sreya; Joseph, Raji E; Andreotti, Amy H; Smithgall, Thomas E; Engen, John R; Wales, Thomas E

    2016-04-01

    The Src Homology 3 (SH3) domain is an important regulatory domain found in many signaling proteins. X-ray crystallography and NMR structures of SH3 domains are generally conserved but other studies indicate that protein flexibility and dynamics are not. We previously reported that based on hydrogen exchange mass spectrometry (HX MS) studies, there is variable flexibility and dynamics among the SH3 domains of the Src-family tyrosine kinases and related proteins. Here we have extended our studies to the SH3 domains of the Tec family tyrosine kinases (Itk, Btk, Tec, Txk, Bmx). The SH3 domains of members of this family augment the variety in dynamics observed in previous SH3 domains. Txk and Bmx SH3 were found to be highly dynamic in solution by HX MS and Bmx was unstructured by NMR. Itk and Btk SH3 underwent a clear EX1 cooperative unfolding event, which was localized using pepsin digestion and mass spectrometry after hydrogen exchange labeling. The unfolding was localized to peptide regions that had been previously identified in the Src-family and related protein SH3 domains, yet the kinetics of unfolding were not. Sequence alignment does not provide an easy explanation for the observed dynamics behavior, yet the similarity of location of EX1 unfolding suggests that higher-order structural properties may play a role. While the exact reason for such dynamics is not clear, such motions can be exploited in intra- and intermolecular binding assays of proteins containing the domains.

  16. Small-Molecule Inhibitors of the Receptor Tyrosine Kinases: Promising Tools for Targeted Cancer Therapies

    Directory of Open Access Journals (Sweden)

    Mohammad Hojjat-Farsangi

    2014-08-01

    Full Text Available Chemotherapeutic and cytotoxic drugs are widely used in the treatment of cancer. In spite of the improvements in the life quality of patients, their effectiveness is compromised by several disadvantages. This represents a demand for developing new effective strategies with focusing on tumor cells and minimum side effects. Targeted cancer therapies and personalized medicine have been defined as a new type of emerging treatments. Small molecule inhibitors (SMIs are among the most effective drugs for targeted cancer therapy. The growing number of approved SMIs of receptor tyrosine kinases (RTKs i.e., tyrosine kinase inhibitors (TKIs in the clinical oncology imply the increasing attention and application of these therapeutic tools. Most of the current approved RTK–TKIs in preclinical and clinical settings are multi-targeted inhibitors with several side effects. Only a few specific/selective RTK–TKIs have been developed for the treatment of cancer patients. Specific/selective RTK–TKIs have shown less deleterious effects compared to multi-targeted inhibitors. This review intends to highlight the importance of specific/selective TKIs for future development with less side effects and more manageable agents. This article provides an overview of: (1 the characteristics and function of RTKs and TKIs; (2 the recent advances in the improvement of specific/selective RTK–TKIs in preclinical or clinical settings; and (3 emerging RTKs for targeted cancer therapies by TKIs.

  17. Antibacterial and EGFR-Tyrosine Kinase Inhibitory Activities of Polyhydroxylated Xanthones from Garcinia succifolia

    Directory of Open Access Journals (Sweden)

    Susawat Duangsrisai

    2014-11-01

    Full Text Available Chemical investigation of the methanol extract of the wood of Garcinia succifolia Kurz (Clusiaceae led to the isolation of 1,5-dihydroxyxanthone (1, 1,7-dihydroxyxanthone (2, 1,3,7-trihydroxyxanthone (3, 1,5,6-trihydroxyxanthone (4, 1,6,7-trihydroxyxanthone (5, and 1,3,6,7-tetrahydroxyxanthone (6. All of the isolated xanthones were evaluated for their antibacterial activity against bacterial reference strains, two Gram-positive (Staphylococcus aureus ATTC 25923, Bacillus subtillis ATCC 6633 and two Gram-negative (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853, and environmental drug-resistant isolates (S. aureus B1, Enteroccoccus faecalis W1, and E. coli G1, as well as for their epidermal growth factor receptor (EGFR of tyrosine kinase inhibitory activity. Only 1,5,6-trihydroxy-(4, 1,6,7-trihydroxy-(5, and 1,3,6,7-tetrahydroxyxanthones (6 exhibited antibacterial activity against Gram-positive bacteria, however none was active against vancomycin-resistant E. faecalis. Additionally, 1,7-dihydroxyxanthone (2 showed synergism with oxacillin, but not with ampicillin. On the other hand, only 1,5-dihydroxyxanthone (1 and 1,7-dihydroxyxanthone (2 were found to exhibit the EGFR-tyrosine kinase inhibitory activity, with IC50 values of 90.34 and 223 nM, respectively.

  18. Baicalin and Baicalein Inhibit Src Tyrosine Kinase and Production of IL-6

    Directory of Open Access Journals (Sweden)

    Dubravko Jelić

    2016-01-01

    Full Text Available Flavonoids play an important role in the treatment of various diseases, as they are able to inhibit reactive oxygen species, which cause damage to cells and tissues which may lead to increased risk of inflammatory diseases. Baicalin and baicalein, two flavonoids found in the roots of Scutellaria baicalensis, in the leaves of Thymus vulgaris and Oroxylum indicum, were tested for their anti-inflammatory activity as well as for their cytotoxicity. Thereby the two compounds were investigated on Src tyrosine kinase inhibition and inhibition of production of interleukin (IL-6 in lipopolysaccharide- (LPS- stimulated THP-1 cells. Additionally, the THP-1 cell line was used for the determination of the cytotoxicity. Both baicalin and baicalein showed some anti-inflammatory properties, while baicalein turned out to be the more active compound with higher inhibitory activities on both Src tyrosine kinase and production of cytokine IL-6. Baicalin and baicalein showed no signs of cytotoxicity in the MTS cytotoxicity assay in THP-1 cells.

  19. Measurement of the formation of complexes in tyrosine kinase-mediated signal transduction

    Energy Technology Data Exchange (ETDEWEB)

    Ladbury, John E., E-mail: j.ladbury@biochem.ucl.ac.uk [Department of Biochemistry and Molecular Biology, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2007-01-01

    The use of isothermal titration calorimetry (ITC) provides a full thermodynamic characterization of an interaction in one experiment. The determination of the affinity is an important value; however, the additional layer of information provided by the change in enthalpy and entropy can help in understanding the biology. This is demonstrated with respect to tyrosine kinase-mediated signal transduction. Isothermal titration calorimetry (ITC) provides highly complementary data to high-resolution structural detail. An overview of the methodology of the technique is provided. Ultimately, the correlation of the thermodynamic parameters determined by ITC with structural perturbation observed on going from the free to the bound state should be possible at an atomic level. Currently, thermodynamic data provide some insight as to potential changes occurring on complex formation. Here, this is demonstrated in the context of in vitro quantification of intracellular tyrosine kinase-mediated signal transduction and the issue of specificity of the important interactions. The apparent lack of specificity in the interactions of domains of proteins involved in early signalling from membrane-bound receptors is demonstrated using data from ITC.

  20. Resistance to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Non-Small Cell Lung Cancer.

    Science.gov (United States)

    Hammerman, Peter S; Jänne, Pasi A; Johnson, Bruce E

    2009-12-15

    Gefitinib and erlotinib are ATP competitive inhibitors of the epidermal growth factor receptor (EGFR) tyrosine kinase and are approved around the world for the treatment of patients with non-small cell lung cancer (NSCLC). Somatic mutations in the EGFR are found in 10 to 40% of patients with NSCLC. Patients with sensitizing somatic mutations of EGFR treated with gefitinib or erlotinib have an initial clinical response of 60 to 80%, approximately twice as high as the responses associated with the administration of conventional platinum-based chemotherapy. However, the efficacy of EGFR tyrosine kinase inhibitors (TKI) is limited by either primary (de novo) or acquired resistance after therapy and investigations to define the mechanisms of resistance are active areas of ongoing preclinical and clinical studies. Primary resistance is typically caused by other somatic mutations in genes such as KRAS, which also have an impact on the EGFR signaling pathway or by mutations in the EGFR gene that are not associated with sensitivity to EGFR-TKIs. Two established mechanisms of acquired resistance are caused by additional mutations in the EGFR gene acquired during the course of treatment that change the protein-coding sequence or by amplification of another oncogene signaling pathway driven by the MET oncogene. This review focuses on characterized mechanisms of resistance to the EGFR TKIs and efforts to overcome the problem of resistance aimed at improving the therapy of patients with NSCLC. (Clin Cancer Res 2009;15(24):7502-9).

  1. Negative regulation of receptor tyrosine kinases: unexpected links to c-Cbl and receptor ubiquitylation

    Institute of Scientific and Technical Information of China (English)

    Chanan RUBIN; Gal GUR; Yosef YARDEN

    2005-01-01

    Intracellular signals mediated by the family of receptor tyrosine kinases play pivotal roles in morphogenesis, cell fate determination and pathogenesis. Precise control of signal amplitude and duration is critical for the fidelity and robustness of these processes. Activation of receptor tyrosine kinases by their cognate growth factors not only leads to propagation of the signal through various biochemical cascades, but also sets in motion multiple attenuation mechanisms that ultimately terminate the active state. Early attenuators pre-exist prior to receptor activation and they act to limit signal propagation. Subsequently, late attenuators, such as Lrig and Sprouty, are transcriptionally induced and further act to dampen the signal. Central to the process of signaling attenuation is the role of the E3 ubiquitin ligase c-Cbl. While Cblmediated processes of receptor ubiquitylation and endocytosis are relatively well understood, the links of Cbl to other negative regulators are just now beginning to be appreciated. Here we review some emerging interfaces between Cbl and the transcriptionally induced negative regulators Lrig and Sprouty.

  2. Ethnic differences in response to epidermal growth factor receptor tyrosine kinase inhibitors.

    Science.gov (United States)

    Calvo, Emiliano; Baselga, José

    2006-05-10

    The identification of somatic mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) in non-small-cell lung cancer (NSCLC) and their correlation with response to EGFR inhibitors has become an important event in the fields of cancer genetics and therapeutics. The initial observation of a higher response to gefitinib and erlotinib in patients of Asian origin was followed by the discovery that they harbor more frequent EGFR mutations in NSCLC; this raises the issue of ethnic diversity in the pathogenesis of given tumors. In a similar fashion, amplification of the closely related HER2 gene, which could also have implications for the treatment of NSCLC, is also more frequent in East Asian patients. On the other hand, EGFR gene amplification may be more prevalent in Western populations. The implication of these findings is that ethnicity may indicate different genetic backgrounds in common tumors that may influence clinical outcome and response to therapy. Therefore, in clinical trials with tyrosine kinase inhibitors and other molecular-targeted therapies, the inclusion of a global population appears to be required.

  3. Bruton's tyrosine kinase is a potential therapeutic target in prostate cancer.

    Science.gov (United States)

    Kokabee, Leila; Wang, Xianhui; Sevinsky, Christopher J; Wang, Wei Lin Winnie; Cheu, Lindsay; Chittur, Sridar V; Karimipoor, Morteza; Tenniswood, Martin; Conklin, Douglas S

    2015-01-01

    Bruton's tyrosine kinase (BTK) is a non-receptor tyrosine kinase that has mainly been studied in haematopoietic cells. We have investigated whether BTK is a potential therapeutic target in prostate cancer. We find that BTK is expressed in prostate cells, with the alternate BTK-C isoform predominantly expressed in prostate cancer cells and tumors. This isoform is transcribed from an alternative promoter and results in a protein with an amino-terminal extension. Prostate cancer cell lines and prostate tumors express more BTK-C transcript than the malignant NAMALWA B-cell line or human lymphomas. BTK protein expression is also observed in tumor tissue from prostate cancer patients. Down regulation of this protein with RNAi or inhibition with BTK-specific inhibitors, Ibrutinib, AVL-292 or CGI-1746 decrease cell survival and induce apoptosis in prostate cancer cells. Microarray results show that inhibiting BTK under these conditions increases expression of apoptosis related genes, while overexpression of BTK-C is associated with elevated expression of genes with functions related to cell adhesion, cytoskeletal structure and the extracellular matrix. These results are consistent with studies that show that BTK signaling is important for adhesion and migration of B cells and suggest that BTK-C may confer similar properties to prostate cancer cells. Since BTK-C is a survival factor for these cells, it represents both a potential biomarker and novel therapeutic target for prostate cancer.

  4. Bruton's Tyrosine Kinase Regulates Shigella flexneri Dissemination in HT-29 Intestinal Cells

    Science.gov (United States)

    Dragoi, Ana-Maria; Talman, Arthur M.

    2013-01-01

    Shigella flexneri is a Gram-negative intracellular pathogen that infects the intestinal epithelium and utilizes actin-based motility to spread from cell to cell. S. flexneri actin-based motility has been characterized in various cell lines, but studies in intestinal cells are limited. Here we characterized S. flexneri actin-based motility in HT-29 intestinal cells. In agreement with studies conducted in various cell lines, we showed that S. flexneri relies on neural Wiskott-Aldrich Syndrome protein (N-WASP) in HT-29 cells. We tested the potential role of various tyrosine kinases involved in N-WASP activation and uncovered a previously unappreciated role for Bruton's tyrosine kinase (Btk) in actin tail formation in intestinal cells. We showed that Btk depletion led to a decrease in N-WASP phosphorylation which affected N-WASP recruitment to the bacterial surface, decreased the number of bacteria displaying actin-based motility, and ultimately affected the efficiency of spread from cell to cell. Finally, we showed that the levels of N-WASP phosphorylation and Btk expression were increased in response to infection, which suggests that S. flexneri infection not only triggers the production of proinflammatory factors as previously described but also manipulates cellular processes required for dissemination in intestinal cells. PMID:23230296

  5. Discovery of Potent Bruton's Tyrosine Kinase Inhibitors Using Ligand Based Modeling.

    Science.gov (United States)

    Mera, Wafa A; Alzihlif, Malek; Taha, Mutasem O; Khanfar, Mohammad A

    2017-01-01

    Bruton's Tyrosine Kinase (BTK) is a one of the Tec tyrosine kinase family. It has an essential role in B-cell development and function. Activation of BTK has been associated with the pathogenesis of many types of lymphomas and leukemia, and involved in non-life threatening autoimmune diseases. In this study, exhaustive pharmacophore modeling was combined with QSAR analyses to examine the structural requirements for anti-BTK activities. Genetic function algorithm (GFA) was coupled with multiple linear regression (MLR) analysis to select the best combinations of physicochemical descriptors and pharmacophoric hypothesis capable of generating predictive and self-consistent QSAR models. The optimum pharmacophores were decorated with exclusion volumes to improve their receiver operating characteristic (ROC) curve properties. The best predictive QSAR model and its corresponding pharmacophore models were validated by discovering of novel promising BTK inhibitors retrieved from the National Cancer Institute (NCI) database. Several potent hits exhibited anti-proliferative activities on U-937 cell-line in low micromolar IC50, and one active compound showed nontoxic activities on normal fibroblast cell line. Our efforts culminated in the identification of potent BTK ligands having desired inhibitory activities and structurally distinct from known active reference compounds (i.e., training compounds) and represent new chemotypes.

  6. The promising impact of ibrutinib, a Bruton's tyrosine kinase inhibitor, for the management of lymphoid malignancies.

    Science.gov (United States)

    Bhatt, Valkal; Alejandro, Linh; Michael, Angela; Ganetsky, Alex

    2014-03-01

    Lymphoid malignancies comprise a heterogeneous group of disorders originating from clonal proliferation of B or T lymphocytes. Treatment of lymphoid neoplasms has traditionally been pursued with cytotoxic chemotherapy. To improve efficacy and ameliorate the adverse effects associated with classic chemotherapy, molecularly targeted therapy has been developed. At the forefront of clinical development is ibrutinib, an inhibitor of Bruton's tyrosine kinase (Btk). Btk is a protein tyrosine kinase that plays an important role in regulating B-cell signaling. Dysregulated Btk results in uncontrolled B-lymphocyte proliferation, differentiation, and survival. Ibrutinib is currently being studied in numerous malignancies of lymphoid origin including chronic lymphocytic leukemia, mantle cell lymphoma, non-Hodgkin lymphoma, follicular lymphoma, and multiple myeloma. Thus far, ibrutinib has demonstrated very promising results in treatment-naive patients as well as those with relapsed or refractory disease with an acceptable safety profile. In this article, we describe the pharmacology, efficacy, and toxicity profile of ibrutinib and depict the potential role that ibrutinib will play in the treatment paradigm of lymphoid neoplasms. © 2013 American College of Clinical Pharmacy.

  7. Effects of 4 multitargeted receptor tyrosine kinase inhibitors on regional hemodynamics in conscious, freely moving rats

    Science.gov (United States)

    Carter, Joanne J.; Fretwell, Laurice V.; Woolard, Jeanette

    2017-01-01

    VEGF inhibitors, including receptor tyrosine kinase inhibitors, are used as adjunct therapies in a number of cancer treatments. An emerging issue with these drugs is that most cause hypertension. To gain insight into the physiological mechanisms involved, we evaluated their regional hemodynamic effects in conscious rats. Male Sprague Dawley rats (350–450 g) were chronically implanted with pulsed Doppler flow probes (renal and mesenteric arteries, and the descending abdominal aorta) and catheters (jugular vein, peritoneal cavity, and distal abdominal aorta). Regional hemodynamics were measured over 4 d, before and after daily administration of cediranib (3 and 6 mg/kg, 3 and 6 mg/kg/h for 1 h, i.v.), sorafenib (10 and 20 mg/kg, 10 and 20 mg kg/h for 1 h, i.v.), pazopanib (30 and100 mg/kg, i.p.), or vandetanib (12.5 and 25 mg/kg, i.p.). All drugs evoked significant increases (P phentolamine and propranolol (each 1 mg/kg/h), suggesting a need for new strategies to overcome them.—Carter, J. J., Fretwell, L. V., Woolard, J. Effects of 4 multitargeted receptor tyrosine kinase inhibitors on regional hemodynamics in conscious, freely moving rats. PMID:27986807

  8. Predominant expression of murine Bmx tyrosine kinase in the granulo-monocytic lineage.

    Science.gov (United States)

    Weil, D; Power, M A; Smith, S I; Li, C L

    1997-12-01

    In the course of systematic cloning of protein tyrosine kinases (PTKs) expressed in hematopoietic stem and progenitor cells, we have identified the murine homologue of human Bmx. It encodes a protein containing the five domains characteristic of the Tec family of cytoplasmic src-related PTKs: pleckstrin homology (PH), Tec homology (TH), src homology 3 and 2 (SH3 and SH2), and tyrosine kinase (TK). In adults, Bmx expression was found primarily in bone marrow and at a lower level in lung and heart. During fetal development it was also found in the spleen at late stage of gestation and in neonates. Analysis of bone marrow subpopulations showed that Bmx was expressed in the progenitor cell population and maturing hematopoietic cells of the granulo/monocytic lineage where expression increased with maturation and differentiation. At the periphery, a high level of Bmx expression was also found in neutrophils and monocytes/macrophages. Bmx expression was not detected in the primitive hematopoietic stem cell population, and cells of the B-, T-, and erythroid-lineages. It was also not detected in most of the cell lines examined. Our results indicate that Bmx is another member of the Btk/Itk/Tec PTK family, which is predominantly expressed in the granulo-monocytic lineage within the hematopoietic system.

  9. Receptor-Tyrosine-Kinase-Targeted Therapies for Head and Neck Cancer

    Directory of Open Access Journals (Sweden)

    Lisa A. Elferink

    2011-01-01

    Full Text Available Molecular therapeutics for treating epidermal growth factor receptor-(EGFR- expressing cancers are a specific method for treating cancers compared to general cell loss with standard cytotoxic therapeutics. However, the finding that resistance to such therapy is common in clinical trials now dampens the initial enthusiasm over this targeted treatment. Yet an improved molecular understanding of other receptor tyrosine kinases known to be active in cancer has revealed a rich network of cross-talk between receptor pathways with a key finding of common downstream signaling pathways. Such cross talk may represent a key mechanism for resistance to EGFR-directed therapy. Here we review the interplay between EGFR and Met and the type 1 insulin-like growth factor receptor (IGF-1R tyrosine kinases, as well as their contribution to anti-EGFR therapeutic resistance in the context of squamous cell cancer of the head and neck, a tumor known to be primarily driven by EGFR-related oncogenic signals.

  10. Characterization of the interactions between the active site of a protein tyrosine kinase and a divalent metal activator

    Directory of Open Access Journals (Sweden)

    Ayrapetov Marina K

    2005-11-01

    Full Text Available Abstract Background Protein tyrosine kinases are important enzymes for cell signalling and key targets for anticancer drug discovery. The catalytic mechanisms of protein tyrosine kinase-catalysed phosphorylation are not fully understood. Protein tyrosine kinase Csk requires two Mg2+ cations for activity: one (M1 binds to ATP, and the other (M2 acts as an essential activator. Results Experiments in this communication characterize the interaction between M2 and Csk. Csk activity is sensitive to pH in the range of 6 to 7. Kinetic characterization indicates that the sensitivity is not due to altered substrate binding, but caused by the sensitivity of M2 binding to pH. Several residues in the active site with potential of binding M2 are mutated and the effect on metal activation studied. An active mutant of Asn319 is generated, and this mutation does not alter the metal binding characteristics. Mutations of Glu236 or Asp332 abolish the kinase activity, precluding a positive or negative conclusion on their role in M2 coordination. Finally, the ability of divalent metal cations to activate Csk correlates to a combination of ionic radius and the coordination number. Conclusion These studies demonstrate that M2 binding to Csk is sensitive to pH, which is mainly responsible for Csk activity change in the acidic arm of the pH response curve. They also demonstrate critical differences in the metal activator coordination sphere in protein tyrosine kinase Csk and a protein Ser/Thr kinase, the cAMP-dependent protein kinase. They shed light on the physical interactions between a protein tyrosine kinase and a divalent metal activator.

  11. Fusion tyrosine kinase mediated signalling pathways in the transformation of haematopoietic cells.

    Science.gov (United States)

    Turner, S D; Alexander, D R

    2006-04-01

    The fusion tyrosine kinases (FTKs) are generated by chromosomal translocations creating bipartite proteins in which the kinase is hyperactivated by an adjoining oligomerization domain. Autophosphorylation of the FTK generates a 'signalosome', an ensemble of signalling proteins that transduce signals to downstream pathways. At the earliest stages of oncogenesis, FTKs can mimic mitogenic cytokine signalling pathways involving the GAB-2 adaptor protein and signal transducers and activators of transcription (STAT) factors, generating replicative stress and thereby promoting a mutator phenotype. In parallel, FTKs couple to survival pathways that upregulate prosurvival proteins such as Bcl-xL, so preventing DNA-damage-induced apoptosis. Following transformation, FTKs induce resistance to genotoxic attack by upregulating DNA repair mechanisms such as STAT5-dependent RAD51 transcription. The phenomenon of 'oncogene addiction' reflects the continued requirement of an active FTK 'signalosome' to mediate survival and mitogenic signals involving the PI 3-kinase and mitogen-activated protein stress-activated protein kinase pathways, and the nuclear factor-kappa B, activator protein 1 and STAT transcription factors. The available data so far suggest that FTKs, with some possible exceptions, induce and maintain the transformed state using similar panoplies of signals, a finding with important therapeutic implications. The FTK signalling field has matured to an exciting phase in which rapid advances are facilitating rational drug design.

  12. Targeting FMS-related tyrosine kinase receptor 3 with the human immunoglobulin G1 monoclonal antibody IMC-EB10.

    Science.gov (United States)

    Youssoufian, Hagop; Rowinsky, Eric K; Tonra, James; Li, Yiwen

    2010-02-15

    FMS-related tyrosine kinase receptor 3 (FLT3) is a class III receptor tyrosine kinase that holds considerable promise as a therapeutic target in hematologic malignancies. Current efforts directed toward the development of small-molecule tyrosine kinase inhibitors of FLT3 may be limited by off-target toxicities and the development of drug resistance. Target-specific antibodies could overcome these hurdles and provide additional mechanisms to enhance the antitumor efficacy of FLT3 inhibitors. IMC-EB10 is a novel antibody directed against FLT3. The binding of IMC-EB10 to FLT3 results in antiproliferative effects in vitro and in mouse models engrafted with human leukemia cells that harbor wild-type or constitutively activated FLT3. Future clinical trials will test these notions formally and will identify the most appropriate opportunities for this member of a new generation of antileukemic therapies.

  13. Differential regulation of protein tyrosine kinase signalling by Dock and the PTP61F variants.

    Science.gov (United States)

    Willoughby, Lee F; Manent, Jan; Allan, Kirsten; Lee, Han; Portela, Marta; Wiede, Florian; Warr, Coral; Meng, Tzu-Ching; Tiganis, Tony; Richardson, Helena E

    2017-07-01

    Tyrosine phosphorylation-dependent signalling is coordinated by the opposing actions of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). There is a growing list of adaptor proteins that interact with PTPs and facilitate the dephosphorylation of substrates. The extent to which any given adaptor confers selectivity for any given substrate in vivo remains unclear. Here we have taken advantage of Drosophila melanogaster as a model organism to explore the influence of the SH3/SH2 adaptor protein Dock on the abilities of the membrane (PTP61Fm)- and nuclear (PTP61Fn)-targeted variants of PTP61F (the Drosophila othologue of the mammalian enzymes PTP1B and TCPTP respectively) to repress PTK signalling pathways in vivo. PTP61Fn effectively repressed the eye overgrowth associated with activation of the epidermal growth factor receptor (EGFR), PTK, or the expression of the platelet-derived growth factor/vascular endothelial growth factor receptor (PVR) or insulin receptor (InR) PTKs. PTP61Fn repressed EGFR and PVR-induced mitogen-activated protein kinase signalling and attenuated PVR-induced STAT92E signalling. By contrast, PTP61Fm effectively repressed EGFR- and PVR-, but not InR-induced tissue overgrowth. Importantly, coexpression of Dock with PTP61F allowed for the efficient repression of the InR-induced eye overgrowth, but did not enhance the PTP61Fm-mediated inhibition of EGFR and PVR-induced signalling. Instead, Dock expression increased, and PTP61Fm coexpression further exacerbated the PVR-induced eye overgrowth. These results demonstrate that Dock selectively enhances the PTP61Fm-mediated attenuation of InR signalling and underscores the specificity of PTPs and the importance of adaptor proteins in regulating PTP function in vivo. © 2017 Federation of European Biochemical Societies.

  14. Identification of nuclear protein targets for six leukemogenic tyrosine kinases governed by post-translational regulation.

    Directory of Open Access Journals (Sweden)

    Andrew Pierce

    Full Text Available Mutated tyrosine kinases are associated with a number of different haematological malignancies including myeloproliferative disorders, lymphoma and acute myeloid leukaemia. The potential commonalities in the action of six of these leukemogenic proteins on nuclear proteins were investigated using systematic proteomic analysis. The effects on over 3600 nuclear proteins and 1500 phosphopeptide sites were relatively quantified in seven isogenic cell lines. The effects of the kinases were diverse although some commonalities were found. Comparison of the nuclear proteomic data with transcriptome data and cytoplasmic proteomic data indicated that the major changes are due to post-translational mechanisms rather than changes in mRNA or protein distribution. Analysis of the promoter regions of genes whose protein levels changed in response to the kinases showed the most common binding site found was that for NFκB whilst other sites such as those for the glucocorticoid receptor were also found. Glucocorticoid receptor levels and phosphorylation were decreased by all 6 PTKs. Whilst Glucocorticoid receptor action can potentiate NFκB action those proteins where genes have NFκB binding sites were in often regulated post-translationally. However all 6 PTKs showed evidence of NFkB pathway modulation via activation via altered IkB and NFKB levels. Validation of a common change was also undertaken with PMS2, a DNA mismatch repair protein. PMS2 nuclear levels were decreased in response to the expression of all 6 kinases, with no concomitant change in mRNA level or cytosolic protein level. Response to thioguanine, that requires the mismatch repair pathway, was modulated by all 6 oncogenic kinases. In summary common targets for 6 oncogenic PTKs have been found that are regulated by post-translational mechanisms. They represent potential new avenues for therapies but also demonstrate the post-translational regulation is a key target of leukaemogenic kinases.

  15. Differential regulation of T cell antigen responsiveness by isoforms of the src-related tyrosine protein kinase p59fyn

    OpenAIRE

    1992-01-01

    Recent observations suggest that the src-related tyrosine protein kinase p59fyn may be involved in antigen-induced T lymphocyte activation. As a result of alternative splicing, p59fyn exists as two isoforms that differ exclusively within a short sequence spanning the end of the Src Homology 2 (SH2) region and the beginning of the tyrosine protein kinase domain. While one p59fyn isoform (fynB) is highly expressed in brain, the alternative product (fynT) is principally found in T lymphocytes. T...

  16. p59fyn tyrosine kinase associates with multiple T-cell receptor subunits through its unique amino-terminal domain.

    OpenAIRE

    1992-01-01

    Several lines of evidence link the protein tyrosine kinase p59fyn to the T-cell receptor. The molecular basis of this interaction has not been established. Here we show that the tyrosine kinase p59fyn can associate with chimeric proteins that contain the cytoplasmic domains of CD3 epsilon, gamma, zeta (zeta), and eta. Mutational analysis of the zeta cytoplasmic domain demonstrated that the membrane-proximal 41 residues of zeta are sufficient for p59fyn binding and that at least two p59fyn bin...

  17. The Activation of c-Src Tyrosine Kinase: Conformational Transition Pathway and Free Energy Landscape.

    Science.gov (United States)

    Fajer, Mikolai; Meng, Yilin; Roux, Benoît

    2016-10-28

    Tyrosine kinases are important cellular signaling allosteric enzymes that regulate cell growth, proliferation, metabolism, differentiation, and migration. Their activity must be tightly controlled, and malfunction can lead to a variety of diseases, particularly cancer. The nonreceptor tyrosine kinase c-Src, a prototypical model system and a representative member of the Src-family, functions as complex multidomain allosteric molecular switches comprising SH2 and SH3 domains modulating the activity of the catalytic domain. The broad picture of self-inhibition of c-Src via the SH2 and SH3 regulatory domains is well characterized from a structural point of view, but a detailed molecular mechanism understanding is nonetheless still lacking. Here, we use advanced computational methods based on all-atom molecular dynamics simulations with explicit solvent to advance our understanding of kinase activation. To elucidate the mechanism of regulation and self-inhibition, we have computed the pathway and the free energy landscapes for the "inactive-to-active" conformational transition of c-Src for different configurations of the SH2 and SH3 domains. Using the isolated c-Src catalytic domain as a baseline for comparison, it is observed that the SH2 and SH3 domains, depending upon their bound orientation, promote either the inactive or active state of the catalytic domain. The regulatory structural information from the SH2-SH3 tandem is allosterically transmitted via the N-terminal linker of the catalytic domain. Analysis of the conformational transition pathways also illustrates the importance of the conserved tryptophan 260 in activating c-Src, and reveals a series of concerted events during the activation process.

  18. Phosphorylation of Staphylococcus aureus Protein-Tyrosine Kinase Affects the Function of Glucokinase and Biofilm Formation

    Science.gov (United States)

    Vasu, Dudipeta; Kumar, Pasupuleti Santhosh; Prasad, Uppu Venkateswara; Swarupa, Vimjam; Yeswanth, Sthanikam; Srikanth, Lokanathan; Sunitha, Manne Mudhu; Choudhary, Abhijith; Krishna Sarma, Potukuchi Venkata Gurunadha

    2017-01-01

    Background: When Staphylococcus aureus is grown in the presence of high concentration of external glucose, this sugar is phosphorylated by glucokinase (glkA) to form glucose-6-phosphate. This product subsequently enters into anabolic phase, which favors biofilm formation. The presence of ROK (repressor protein, open reading frame, sugar kinase) motif, phosphate-1 and -2 sites, and tyrosine kinase sites in glkA of S. aureus indicates that phosphorylation must regulate the glkA activity. The aim of the present study was to identify the effect of phosphorylation on the function of S. aureus glkA and biofilm formation. Methods: Pure glkA and protein-tyrosine kinase (BYK) of S. aureus ATCC 12600 were obtained by fractionating the cytosolic fractions of glkA1 and BYK-1 expressing recombinant clones through nickel metal chelate column. The pure glkA was used as a substrate for BYK, and the phosphorylation of glkA was confirmed by treating with reagent A and resolving in SDS-PAGE, as well as staining with reagent A. The kinetic parameters of glkA and phosphorylated glkA were determined spectrophotometrically, and in silico tools were used for validation. S. aureus was grown in brain heart infusion broth, which was supplemented with glucose, and then biofilm units were calculated. Results: Fourfold elevated glkA activity was observed upon the phosphorylation by BYK. Protein-protein docking analysis revealed that glkA structure docked close to the adenosine triphosphate-binding site of BYK structure corroborating the kinetic results. Further, S. aureus grown in the presence of elevated glucose concentration exhibited an increase in the rate of biofilm formation. Conclusion: The elevated function of glkA is an essential requirement for increased biofilm units in S. aureus, a key pathogenic factor that helps its survival and the progress of infection. PMID:27695030

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

    Directory of Open Access Journals (Sweden)

    Bearss David

    2009-12-01

    Full Text Available Abstract Purpose 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. Materials and methods 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. Results 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. Conclusions 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.

  20. Protein tyrosine kinase signaling in the mouse oocyte cortex during sperm-egg interactions and anaphase resumption.

    Science.gov (United States)

    McGinnis, Lynda K; Luo, Jinping; Kinsey, William H

    2013-04-01

    Fertilization triggers activation of a series of pre-programmed signal transduction pathways in the oocyte that establish a block to polyspermy, induce meiotic resumption, and initiate zygotic development. Fusion between sperm and oocyte results in rapid changes in oocyte intracellular free-calcium levels, which in turn activate multiple protein kinase cascades in the ooplasm. The present study examined the possibility that sperm-oocyte interaction involves localized activation of oocyte protein tyrosine kinases, which could provide an alternative signaling mechanism to that triggered by the fertilizing sperm. Confocal immunofluorescence analysis with antibodies to phosphotyrosine and phosphorylated protein tyrosine kinases allowed detection of minute signaling events localized to the site of sperm-oocyte interaction that were not amenable to biochemical analysis. The results provide evidence for localized accumulation of phosphotyrosine at the site of sperm contact, binding, or fusion, which suggests active protein tyrosine kinase signaling prior to and during sperm incorporation. The PYK2 kinase was found to be concentrated and activated at the site of sperm-oocyte interaction, and likely participates in this response. Widespread activation of PYK2 and FAK kinases was subsequently observed within the oocyte cortex, indicating that sperm incorporation is followed by more global signaling via these kinases during meiotic resumption. The results demonstrate an alternate signaling pathway triggered in mammalian oocytes by sperm contact, binding, or fusion with the oocyte.

  1. Small Molecule Tyrosine Kinase Inhibitors of ErbB2/HER2/Neu in the Treatment of Aggressive Breast Cancer

    Directory of Open Access Journals (Sweden)

    Richard L. Schroeder

    2014-09-01

    Full Text Available The human epidermal growth factor receptor 2 (HER2 is a member of the erbB class of tyrosine kinase receptors. These proteins are normally expressed at the surface of healthy cells and play critical roles in the signal transduction cascade in a myriad of biochemical pathways responsible for cell growth and differentiation. However, it is widely known that amplification and subsequent overexpression of the HER2 encoding oncogene results in unregulated cell proliferation in an aggressive form of breast cancer known as HER2-positive breast cancer. Existing therapies such as trastuzumab (Herceptin® and lapatinib (Tyverb/Tykerb®, a monoclonal antibody inhibitor and a dual EGFR/HER2 kinase inhibitor, respectively, are currently used in the treatment of HER2-positive cancers, although issues with high recurrence and acquired resistance still remain. Small molecule tyrosine kinase inhibitors provide attractive therapeutic targets, as they are able to block cell signaling associated with many of the proposed mechanisms for HER2 resistance. In this regard we aim to present a review on the available HER2 tyrosine kinase inhibitors, as well as those currently in development. The use of tyrosine kinase inhibitors as sequential or combinatorial therapeutic strategies with other HER family inhibitors is also discussed.

  2. Phosphorylation of cystic fibrosis transmembrane conductance regulator (CFTR) serine-511 by the combined action of tyrosine kinases and CK2: the implication of tyrosine-512 and phenylalanine-508.

    Science.gov (United States)

    Cesaro, Luca; Marin, Oriano; Venerando, Andrea; Donella-Deana, Arianna; Pinna, Lorenzo A

    2013-12-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) harbors, close to Phe-508, whose deletion is the commonest cause of cystic fibrosis, a conserved potential CK2 phospho-acceptor site (Ser511), which however is not susceptible to phosphorylation by CK2. To shed light on this apparent paradox, a series of systematically substituted peptides encompassing Ser511 were assayed for their ability to be phosphorylated. The main outcomes of our study are the following: (a) Tyr512 plays a prominent role as a negative determinant as its replacement by Ala restores Ser511 phosphorylation by CK2; (b) an even more pronounced phosphorylation of Ser511 is promoted if Tyr512 is replaced by phospho-tyrosine instead of alanine; (c) Tyr512 and, to a lesser extent, Tyr515 are readily phosphorylated by Lyn, a protein tyrosine kinase of the Src family, in a manner which is enhanced by the concomitant Phe508 deletion. Collectively taken, our data, in conjunction with the notion that Tyr515 is phosphorylated in vivo, disclose the possibility that CFTR Ser511 can be phosphorylated by the combined action of tyrosine kinases and CK2 and disclose a new mechanism of hierarchical phosphorylation where the role of the priming kinase is that of removing negative determinant(s).

  3. Structures of human Bruton's tyrosine kinase in active and inactive conformations suggest a mechanism of activation for TEC family kinases

    Energy Technology Data Exchange (ETDEWEB)

    Marcotte, Douglas J.; Liu, Yu-Ting; Arduini, Robert M.; Hession, Catherine A.; Miatkowski, Konrad; Wildes, Craig P.; Cullen, Patrick F.; Hong, Victor; Hopkins, Brian T.; Mertsching, Elisabeth; Jenkins, Tracy J.; Romanowski, Michael J.; Baker, Darren P.; Silvian, Laura F. (Sunesis); (Biogen)

    2010-11-15

    Bruton's tyrosine kinase (BTK), a member of the TEC family of kinases, plays a crucial role in B-cell maturation and mast cell activation. Although the structures of the unphosphorylated mouse BTK kinase domain and the unphosphorylated and phosphorylated kinase domains of human ITK are known, understanding the kinase selectivity profiles of BTK inhibitors has been hampered by the lack of availability of a high resolution, ligand-bound BTK structure. Here, we report the crystal structures of the human BTK kinase domain bound to either Dasatinib (BMS-354825) at 1.9 {angstrom} resolution or to 4-amino-5-(4-phenoxyphenyl)-7H-pyrrolospyrimidin- 7-yl-cyclopentane at 1.6 {angstrom} resolution. This data provides information relevant to the development of small molecule inhibitors targeting BTK and the TEC family of nonreceptor tyrosine kinases. Analysis of the structural differences between the TEC and Src families of kinases near the Trp-Glu-Ile motif in the N-terminal region of the kinase domain suggests a mechanism of regulation of the TEC family members.

  4. Proteomic and functional genomic landscape of receptor tyrosine kinase and ras to extracellular signal-regulated kinase signaling.

    Science.gov (United States)

    Friedman, Adam A; Tucker, George; Singh, Rohit; Yan, Dong; Vinayagam, Arunachalam; Hu, Yanhui; Binari, Richard; Hong, Pengyu; Sun, Xiaoyun; Porto, Maura; Pacifico, Svetlana; Murali, Thilakam; Finley, Russell L; Asara, John M; Berger, Bonnie; Perrimon, Norbert

    2011-10-25

    Characterizing the extent and logic of signaling networks is essential to understanding specificity in such physiological and pathophysiological contexts as cell fate decisions and mechanisms of oncogenesis and resistance to chemotherapy. Cell-based RNA interference (RNAi) screens enable the inference of large numbers of genes that regulate signaling pathways, but these screens cannot provide network structure directly. We describe an integrated network around the canonical receptor tyrosine kinase (RTK)-Ras-extracellular signal-regulated kinase (ERK) signaling pathway, generated by combining parallel genome-wide RNAi screens with protein-protein interaction (PPI) mapping by tandem affinity purification-mass spectrometry. We found that only a small fraction of the total number of PPI or RNAi screen hits was isolated under all conditions tested and that most of these represented the known canonical pathway components, suggesting that much of the core canonical ERK pathway is known. Because most of the newly identified regulators are likely cell type- and RTK-specific, our analysis provides a resource for understanding how output through this clinically relevant pathway is regulated in different contexts. We report in vivo roles for several of the previously unknown regulators, including CG10289 and PpV, the Drosophila orthologs of two components of the serine/threonine-protein phosphatase 6 complex; the Drosophila ortholog of TepIV, a glycophosphatidylinositol-linked protein mutated in human cancers; CG6453, a noncatalytic subunit of glucosidase II; and Rtf1, a histone methyltransferase.

  5. Protein-tyrosine kinase activity profiling in knock down zebrafish embryos.

    Directory of Open Access Journals (Sweden)

    Simone Lemeer

    Full Text Available BACKGROUND: Protein-tyrosine kinases (PTKs regulate virtually all biological processes. PTKs phosphorylate substrates in a sequence-specific manner and relatively short peptide sequences determine selectivity. Here, we developed new technology to determine PTK activity profiles using peptide arrays. The zebrafish is an excellent model system to investigate signaling in the whole organism, given its wealth of genetic tools, including morpholino-mediated knock down technology. We used zebrafish embryo lysates to determine PTK activity profiles, thus providing the unique opportunity to directly compare the effect of protein knock downs on PTK activity profiles on the one hand and phenotypic changes on the other. METHODOLOGY: We used multiplex arrays of 144 distinct peptides, spotted on a porous substrate, allowing the sample to be pumped up and down, optimizing reaction kinetics. Kinase reactions were performed using complex zebrafish embryo lysates or purified kinases. Peptide phosphorylation was detected by fluorescent anti-phosphotyrosine antibody binding and the porous chips allowed semi-continuous recording of the signal. We used morpholinos to knock down protein expression in the zebrafish embryos and subsequently, we determined the effects on the PTK activity profiles. RESULTS AND CONCLUSION: Reproducible PTK activity profiles were derived from one-day-old zebrafiish embryos. Morpholino-mediated knock downs of the Src family kinases, Fyn and Yes, induced characteristic phenotypes and distinct changes in the PTK activity profiles. Interestingly, the peptide substrates that were less phosphorylated upon Fyn and Yes knock down were preferential substrates of purified Fyn and Yes. Previously, we demonstrated that Wnt11 knock down phenocopied Fyn/Yes knock down. Interestingly, Wnt11 knock down induced similar changes in the PTK activity profile as Fyn/Yes knock down. The control Nacre/Mitfa knock down did not affect the PTK activity profile

  6. Bruton's tyrosine kinase regulates the activation of gene rearrangements at the lambda light chain locus in precursor B cells in the mouse

    NARCIS (Netherlands)

    G.M. Dingjan (Gemma); S. Middendorp; K. Dahlenborg; A. Maas (Alex); R.W. Hendriks (Rudi); F.G. Grosveld (Frank)

    2001-01-01

    textabstractBruton's tyrosine kinase (Btk) is a nonreceptor tyrosine kinase involved in precursor B (pre-B) cell receptor signaling. Here we demonstrate that Btk-deficient mice have an approximately 50% reduction in the frequency of immunoglobulin (Ig) lambda light

  7. Bruton's tyrosine kinase regulates the activation of gene rearrangements at the lambda light chain locus in precursor B cells in the mouse

    NARCIS (Netherlands)

    G.M. Dingjan (Gemma); S. Middendorp; K. Dahlenborg; A. Maas (Alex); R.W. Hendriks (Rudi); F.G. Grosveld (Frank)

    2001-01-01

    textabstractBruton's tyrosine kinase (Btk) is a nonreceptor tyrosine kinase involved in precursor B (pre-B) cell receptor signaling. Here we demonstrate that Btk-deficient mice have an approximately 50% reduction in the frequency of immunoglobulin (Ig) lambda light chai

  8. Identification and regulation of receptor tyrosine kinases Rse and Mer and their ligand Gas6 in testicular somatic cells.

    Science.gov (United States)

    Chan, M C; Mather, J P; McCray, G; Lee, W M

    2000-01-01

    Receptor tyrosine kinases act to convey extracellular signals to intracellular signaling pathways and ultimately control cell proliferation and differentiation. Rse, Axl, and Mer belong to a newly identified family of cell adhesion molecule-related receptor tyrosine kinase. They bind the vitamin K-dependent protein growth arrest-specific gene 6 (Gas6), which is also structurally related to the anticoagulation factor Protein S. The aim of this study is to investigate the possible role of Rse/Axl/Mer tyrosine kinase receptors and their ligand in regulating testicular functions. Gene expression of Rse, Axl, Mer, and Gas6 in the testis was studied by reverse transcriptase-polymerase chain reaction (RT-PCR) and Northern blot analysis. The results indicated that receptors Rse and Mer and the ligand Gas6 were expressed in the rat endothelial cell line (TR1), mouse Leydig cell line (TM3), rat peritubular myoid cell line (TRM), mouse Sertoli cell line (TM4), and primary rat Sertoli cells. Axl was not expressed in the testicular somatic cells by RT-PCR or Northern blot analysis. The highest level of expression of Gas6 messenger RNA (mRNA) was observed in the Sertoli cells, and its expression was responsive to the addition of forskolin in vitro. The effects of serum, insulin, and transferrin on Gas6 expression by TM4 cells were examined. It was shown that they all exhibited an up-regulating effect on Gas6 expression. The forskolin-stimulated Gas6 expression was accompanied by an increase in tyrosine phosphorylation of the Rse receptor in vitro, suggesting that Gas6 may exhibit an autocrine effect in the Sertoli cells through multiple tyrosine kinase receptors. Our studies so far have demonstrated that tyrosine kinase receptors Rse and Mer and their ligand Gas6 are widely expressed in the testicular somatic cell lines and may play a marked role in promoting testicular cell survival.

  9. Comparative VEGF receptor tyrosine kinase modeling for the development of highly specific inhibitors of tumor angiogenesis.

    Science.gov (United States)

    Schmidt, Ulrike; Ahmed, Jessica; Michalsky, Elke; Hoepfner, Michael; Preissner, Robert

    2008-01-01

    The Vascular Endothelial Growth Factor receptors (VEGF-Rs) play a significant role in tumor development and tumor angiogenesis and are therefore interesting targets in cancer therapy. Targeting the VEGF-R is of special importance as the feed of the tumor has to be reduced. In general, this can be carried out by inhibiting the tyrosine kinase function of the VEGF-R. Nevertheless, there arise some problems with the specificity of known kinase inhibitors: they bind to the ATP-binding site and inhibit a number of kinases, moreover the so far most specific inhibitors act at least on these three major types of VEGF-Rs: Flt-1, Flk-1/KDR, Flt-4. The goal is a selective VEGF-R-2 (Flk-1/KDR) inhibitor, because this receptor triggers rather unspecific signals from VEGF-A, -C, -D and -E. Here, we describe a protocol starting from an established inhibitor (Vatalanib) with 2D-/3D-searching and property filtering of the in silico screening hits and the "negative docking approach". With this approach we were able to identify a compound, which shows a fourfold higher reduction of the proliferation rate of endothelial cells compared to the reduction effect of the lead structure.

  10. An overview of the binding models of FGFR tyrosine kinases in complex with small molecule inhibitors.

    Science.gov (United States)

    Cheng, Weiyan; Wang, Mixiang; Tian, Xin; Zhang, Xiaojian

    2017-01-27

    The fibroblast growth factor receptor (FGFR) family receptor tyrosine kinase (RTK) includes four structurally related members, termed as FGFR1, FGFR2, FGFR3, and FGFR4. Given its intimate role in the progression of several solid tumors, excessive FGFR signaling provides an opportunity for anticancer therapy. Along with extensive pharmacological studies validating the therapeutic potential of targeting the FGFRs for cancer treatment, co-crystal structures of FGFRs/inhibitors are continuously coming up to study the mechanism of actions and explore new inhibitors. Herein, we review the reported co-crystals of FGFRs in complex with the corresponding inhibitors, main focusing our attention on the binding models and the pharmacological activities of the inhibitors.

  11. The C. elegans ROR receptor tyrosine kinase, CAM-1, non-autonomously inhibits the Wnt pathway.

    Science.gov (United States)

    Green, Jennifer L; Inoue, Takao; Sternberg, Paul W

    2007-11-01

    Inhibitors of Wnt signaling promote normal development and prevent cancer by restraining when and where the Wnt pathway is activated. ROR proteins, a class of Wnt-binding receptor tyrosine kinases, inhibit Wnt signaling by an unknown mechanism. To clarify how RORs inhibit the Wnt pathway, we examined the relationship between Wnts and the sole C. elegans ROR homolog, cam-1, during C. elegans vulval development, a Wnt-regulated process. We found that loss and overexpression of cam-1 causes reciprocal defects in Wnt-mediated cell-fate specification. Our molecular and genetic analyses revealed that the CAM-1 extracellular domain (ECD) is sufficient to non-autonomously antagonize multiple Wnts, suggesting that the CAM-1/ROR ECD sequesters Wnts. A sequestration model is supported by our findings that the CAM-1 ECD binds to several Wnts in vitro. These results demonstrate how ROR proteins help to refine the spatial pattern of Wnt activity in a complex multicellular environment.

  12. Greater Sensitivity of Blood Pressure Than Renal Toxicity to Tyrosine Kinase Receptor Inhibition With Sunitinib

    DEFF Research Database (Denmark)

    Lankhorst, Stephanie; Baelde, Hans J; Kappers, Mariëtte H W

    2015-01-01

    of these side effects. Normotensive Wistar Kyoto rats were exposed to 3 different doses of sunitinib or vehicle. After 8 days, rats were euthanized. Telemetrically measured blood pressure rose dose dependently, from 13 to 30 mm Hg. Proteinuria was present at all doses, but a rise in cystatin C occurred only...... histological abnormalities with the low dose. Podocyte number per glomerular circumference did not change. Glomerular nephrin, Neph1, podocin, and endothelin-converting enzyme gene expression were downregulated in a dose-dependent manner. We conclude that the sunitinib-induced rise in blood pressure requires......Hypertension and renal injury are off-target effects of sunitinib, a tyrosine kinase receptor inhibitor used for the treatment of various tumor types. Importantly, these untoward effects are accompanied by activation of the endothelin system. Here, we set up a study to explore the dose dependency...

  13. Intermittent targeting as a tool to minimize toxicity of tyrosine kinase inhibitor therapy.

    Science.gov (United States)

    Martinelli, Giovanni; Soverini, Simona; Iacobucci, Ilaria; Baccarani, Michele

    2009-02-01

    Tyrosine kinase inhibitor therapy has revolutionized the outcome of chronic myeloid leukemia (CML), and has transformed a fatal disease into a chronic condition for most patients. At present, the therapeutic armamentarium against CML includes imatinib for newly diagnosed patients, and dasatinib and nilotinib, which have both received marketing approval, for imatinib-resistant and imatinib-intolerant disease. Research efforts are now focused on how to optimize therapeutic strategies in an attempt to improve clinical results further, counteract the development of drug resistance and reduce adverse effects. A randomized, international, phase III study of dasatinib dose and schedule optimization in imatinib-resistant and imatinib-intolerant patients with CML has demonstrated that intermittent target inhibition can preserve therapeutic efficacy and reduce toxicity. This finding has important implications, not only for patients with CML, but also for the development of targeted therapies for human malignancies in general.

  14. The TAM family receptor tyrosine kinase TYRO3 is a negative regulator of type 2 immunity

    Science.gov (United States)

    Chan, Pamela Y.; Carrera Silva, Eugenio A.; De Kouchkovsky, Dimitri; Joannas, Leonel D.; Hao, Liming; Hu, Donglei; Huntsman, Scott; Eng, Celeste; Licona-Limón, Paula; Weinstein, Jason S.; Herbert, De’Broski R.; Craft, Joseph E.; Flavell, Richard A.; Repetto, Silvia; Correale, Jorge; Burchard, Esteban G.; Torgerson, Dara G.; Ghosh, Sourav; Rothlin, Carla V.

    2016-01-01

    Host responses against metazoan parasites or an array of environmental substances elicit type 2 immunity. Despite its protective function, type 2 immunity also drives allergic diseases. The mechanisms that regulate the magnitude of the type 2 response remain largely unknown. Here, we show that genetic ablation of a receptor tyrosine kinase encoded by Tyro3 in mice or the functional neutralization of its ortholog in human dendritic cells resulted in enhanced type 2 immunity. Furthermore, the TYRO3 agonist PROS1 was induced in T cells by the quintessential type 2 cytokine, interleukin-4. T cell–specific Pros1 knockouts phenocopied the loss of Tyro3. Thus, a PROS1-mediated feedback from adaptive immunity engages a rheostat, TYRO3, on innate immune cells to limit the intensity of type 2 responses. PMID:27034374

  15. Bruton's tyrosine kinase: from X-linked agammaglobulinemia toward targeted therapy for B-cell malignancies.

    Science.gov (United States)

    Ponader, Sabine; Burger, Jan A

    2014-06-10

    Discovery of Bruton's tyrosine kinase (BTK) mutations as the cause for X-linked agammaglobulinemia was a milestone in understanding the genetic basis of primary immunodeficiencies. Since then, studies have highlighted the critical role of this enzyme in B-cell development and function, and particularly in B-cell receptor signaling. Because its deletion affects mostly B cells, BTK has become an attractive therapeutic target in autoimmune disorders and B-cell malignancies. Ibrutinib (PCI-32765) is the most advanced BTK inhibitor in clinical testing, with ongoing phase III clinical trials in patients with chronic lymphocytic leukemia and mantle-cell lymphoma. In this article, we discuss key discoveries related to BTK and clinically relevant aspects of BTK inhibitors, and we provide an outlook into clinical development and open questions regarding BTK inhibitor therapy.

  16. Mutations of Bruton's tyrosine kinase gene in Brazilian patients with X-linked agammaglobulinemia.

    Science.gov (United States)

    Ramalho, V D; Oliveira Júnior, E B; Tani, S M; Roxo Júnior, P; Vilela, M M S

    2010-09-01

    Mutations in Bruton's tyrosine kinase (BTK) gene are responsible for X-linked agammaglobulinemia (XLA), which is characterized by recurrent bacterial infections, profound hypogammaglobulinemia, and decreased numbers of mature B cells in peripheral blood. We evaluated 5 male Brazilian patients, ranging from 3 to 10 years of age, from unrelated families, whose diagnosis was based on recurrent infections, markedly reduced levels of IgM, IgG and IgA, and circulating B cell numbers <2%. BTK gene analysis was carried out using PCR-SSCP followed by sequencing. We detected three novel (Ala347fsX55, I355T, and Thr324fsX24) and two previously reported mutations (Q196X and E441X). Flow cytometry revealed a reduced expression of BTK protein in patients and a mosaic pattern of BTK expression was obtained from mothers, indicating that they were XLA carriers.

  17. Mutations of Bruton's tyrosine kinase gene in Brazilian patients with X-linked agammaglobulinemia

    Directory of Open Access Journals (Sweden)

    V.D. Ramalho

    2010-09-01

    Full Text Available Mutations in Bruton's tyrosine kinase (BTK gene are responsible for X-linked agammaglobulinemia (XLA, which is characterized by recurrent bacterial infections, profound hypogammaglobulinemia, and decreased numbers of mature B cells in peripheral blood. We evaluated 5 male Brazilian patients, ranging from 3 to 10 years of age, from unrelated families, whose diagnosis was based on recurrent infections, markedly reduced levels of IgM, IgG and IgA, and circulating B cell numbers <2%. BTK gene analysis was carried out using PCR-SSCP followed by sequencing. We detected three novel (Ala347fsX55, I355T, and Thr324fsX24 and two previously reported mutations (Q196X and E441X. Flow cytometry revealed a reduced expression of BTK protein in patients and a mosaic pattern of BTK expression was obtained from mothers, indicating that they were XLA carriers.

  18. Tyrosine kinase inhibitors in the treatment of systemic sclerosis: from animal models to clinical trials.

    Science.gov (United States)

    Iwamoto, Naoki; Distler, Jörg H W; Distler, Oliver

    2011-02-01

    Efficient antifibrotic therapies are not available for patients with systemic sclerosis (SSc). This review summarizes the current preclinical and clinical evidence for imatinib and related tyrosine kinase inhibitors as potential antifibrotic therapies for SSc and other fibrotic diseases. In experimental models of SSc, imatinib, nilotinib, and dasatinib demonstrated strong antifibrotic effects. Imatinib not only prevented fibrosis in the bleomycin-induced model of dermal fibrosis and the tight skin mouse-1 model but also reduced established fibrosis in a modified bleomycin model. Open-label, proof-of-concept trials in SSc showed moderate effects on skin fibrosis, biological measures of skin fibrosis, and lung fibrosis compared with baseline measures. However, whether this reflects the natural course of the disease or is a result of treatment effects is unclear and needs to be analyzed in larger, multicenter, randomized, placebo-controlled trials. Toxicity is expected from cancer trials with frequent mild to moderate adverse events.

  19. Bruton's Tyrosine Kinase: From X-Linked Agammaglobulinemia Toward Targeted Therapy for B-Cell Malignancies

    Science.gov (United States)

    Ponader, Sabine; Burger, Jan A.

    2014-01-01

    Discovery of Bruton's tyrosine kinase (BTK) mutations as the cause for X-linked agammaglobulinemia was a milestone in understanding the genetic basis of primary immunodeficiencies. Since then, studies have highlighted the critical role of this enzyme in B-cell development and function, and particularly in B-cell receptor signaling. Because its deletion affects mostly B cells, BTK has become an attractive therapeutic target in autoimmune disorders and B-cell malignancies. Ibrutinib (PCI-32765) is the most advanced BTK inhibitor in clinical testing, with ongoing phase III clinical trials in patients with chronic lymphocytic leukemia and mantle-cell lymphoma. In this article, we discuss key discoveries related to BTK and clinically relevant aspects of BTK inhibitors, and we provide an outlook into clinical development and open questions regarding BTK inhibitor therapy. PMID:24778403

  20. The role of Bruton's tyrosine kinase in autoimmunity and implications for therapy.

    Science.gov (United States)

    Crofford, Leslie J; Nyhoff, Lindsay E; Sheehan, Jonathan H; Kendall, Peggy L

    2016-07-01

    Bruton's tyrosine kinase (BTK) mediates B cell signaling and is also present in innate immune cells but not T cells. BTK propagates B cell receptor (BCR) responses to antigen-engagement as well as to stimulation via CD40, toll-like receptors (TLRs), Fc receptors (FCRs) and chemokine receptors. Importantly, BTK can modulate signaling, acting as a "rheostat" rather than an "on-off" switch; thus, overexpression leads to autoimmunity while decreased levels improve autoimmune disease outcomes. Autoreactive B cells depend upon BTK for survival to a greater degree than normal B cells, reflected as loss of autoantibodies with maintenance of total antibody levels when BTK is absent. This review describes contributions of BTK to immune tolerance, including studies testing BTK-inhibitors for treatment of autoimmune diseases.

  1. The role of Bruton’s tyrosine kinase in autoimmunity and implications for therapy

    Science.gov (United States)

    Crofford, Leslie J; Nyhoff, Lindsay; Sheehan, Johnathan; Kendall, Peggy

    2016-01-01

    Summary Bruton’s tyrosine kinase (BTK) mediates B cell signaling and is also present in innate immune cells but not T cells. BTK propagates B cell receptor (BCR) responses to antigen-engagement as well as to stimulation via CD40, toll-like receptors (TLRs), Fc receptors (FCRs) and chemokine receptors. Importantly, BTK can modulate signaling, acting as a “rheostat” rather than an “on-off” switch; thus, overexpression leads to autoimmunity while decreased levels improve autoimmune disease outcomes. Autoreactive B cells depend upon BTK for survival to a greater degree than normal B cells, reflected as loss of autoantibodies with maintenance of total antibody levels when BTK is absent. This review describes contributions of BTK to immune tolerance, including studies testing BTK-inhibitors for treatment of autoimmune diseases. PMID:26864273

  2. Expression of Bruton's tyrosine kinase in B-cell neoplasms evaluated by flow cytometry.

    Science.gov (United States)

    Marcondes, Natália Aydos; Fernandes, Flavo Beno; Alegretti, Ana Paula; Faulhaber, Gustavo Adolpho Moreira

    2016-12-27

    Bruton's tyrosine kinase (BTK) is a cytoplasmatic protein that is part of the B-cell antigen receptor signaling pathway. Our aim was to evaluate the expression of BTK in B-cell neoplasms and compare it to normal B-cell lymphocytes. After surface staining with CD19 and CD45, flow cytometry staining for intracellular BTK was performed in leukemic or mature B-cells from bone marrow or peripheral blood samples. No differences in BTK expression were identified between groups, or in comparison to control samples, there was no association between BTK expression and the clinical variables evaluated. BTK expression in B-cell neoplasms was similar to that of normal B-cell lymphocytes.

  3. Bmx tyrosine kinase transgene induces skin hyperplasia, inflammatory angiogenesis, and accelerated wound healing.

    Science.gov (United States)

    Paavonen, Karri; Ekman, Niklas; Wirzenius, Maria; Rajantie, Iiro; Poutanen, Matti; Alitalo, Kari

    2004-09-01

    The Bmx gene, a member of the Tec family of nonreceptor protein tyrosine kinases, is expressed in arterial endothelium and in certain hematopoietic and epithelial cells. Previous in vitro studies have implicated Bmx signaling in cell migration and survival and suggested that it contributes to the progression of prostate carcinomas. However, the function of Bmx in normal tissues in vivo is unknown. We show here that Bmx expression is induced in skin keratinocytes during wound healing. To analyze the role of Bmx in epidermal keratinocytes in vivo, we generated transgenic mice overexpressing Bmx in the skin. We show that Bmx overexpression accelerates keratinocyte proliferation and wound reepithelialization. Bmx expression also induces chronic inflammation and angiogenesis in the skin, and gene expression profiling suggests that this occurs via cytokine-mediated recruitment of inflammatory cells. Our studies provide the first data on Bmx function in vivo and form the basis of evaluation of its role in epithelial neoplasia.

  4. Using 2 nd generation tyrosine kinase inhibitors in frontline management of chronic phase chronic myeloid leukemia

    Directory of Open Access Journals (Sweden)

    Vishal Jayakar

    2014-01-01

    Full Text Available Choices in medicine come with responsibility. With several TKI′s (Tyrosine kinase inhibitors available for front-line management of CML (Chronic Myeloid Leukemia, an astute clinician has to personalise, rationalise and take a pragmatic approach towards selection of the best drug for the ′patient in question′. Though it is hotly debated as to which TKI will triumph, the truth of this debate lies in individualising treatment rather than a general ′all size fits all′ approach with imatinib. I personally believe that the second generation TKI′s will suit most patient clinical profiles rather than prescribing imatinib to all and I have strived to make a strong case for them in front line treatment of CML. Though Imatinib may remain the first line choice for some patients, my efforts in this debate are mainly geared towards breaking the myth that imatinib is the sole ′block buster′ on the CML landscape

  5. Preparation and Characterization of {sup 177}Lu Labeled Antibody against Tyrosine Kinase Receptor Her2

    Energy Technology Data Exchange (ETDEWEB)

    Lee, So-Young; Hong, Young-Don; Choi, Sun-Ju [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-05-15

    The tyrosine kinase receptor Her2, also known in humans as erbB2, is a member of the epidermal growth factor receptor (EGFR or erbB1) family. The Her2 is highly expressed in many cancer types and over expressed in approximately 30% of all primary breast cancer. Overexpression of Her2 is associated with a poor prognosis. Her2 is a suitable target because it involves an extracellular domain that can be targeted by antibodies produced by B cells. Based on these advantages, we tried to prepare the {sup 177}Lu labeled Her2 antibody. This radioimmunoconjugate could act by not only blocking the Her2 signalling pathway using antibody but also killing the tumour cell using {beta} energy of {sup 177}Lu.

  6. Non-radioisotopic method for the in vitro measurement of EGF receptor tyrosine kinase

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A non-radioisotopic method was developed for the assay ofepidermal growth factor receptor (EGFR). A peptide with twenty amino acid residues around Tyr 1173, the major phosphorylation site of EGFR, was cloned as a GST fusion protein and used as substrate. Anti-phosphotyrosine monoclonal antibody PY99 was used for the determination of the extent of phosphorylation. Both the specificity and the sensitivity were substantially higher than that of the existing method. Km value of the fusion protein is much lower (10 (mol/L) than that of the synthetic peptide (110 (mol/L). The method can be applied to the measurement of the tyrosine kinase activity of c-erb B2 (Neu/HER2).

  7. Ibrutinib: a novel Bruton's tyrosine kinase inhibitor with outstanding responses in patients with chronic lymphocytic leukemia.

    Science.gov (United States)

    Barrientos, Jacqueline; Rai, Kanti

    2013-08-01

    New treatment options are urgently needed for patients with relapsed chronic lymphocytic leukemia (CLL) who fail to respond to currently available therapies or cannot achieve a sustained response. Moreover, targeted agents with less myelotoxicity are necessary to treat patients with multiple comorbidities who would otherwise be unable to tolerate standard regimens. Ibrutinib, a Bruton's tyrosine kinase inhibitor, has shown highly encouraging results in phase I/II trials in patients with treatment-naive, relapsed and refractory CLL even in the presence of high risk disease or poor prognostic markers. In phase I/II trials, ibrutinib 420 mg or 840 mg - given continuously as single agent or at a dose of 420 mg daily in combination with a monoclonal antibody or chemoimmunotherapy - has been associated with high response rates and durable clinical remissions. Phase II and III trials are currently under way for treatment-naive patients, relapsed/refractory patients, and for those patients harboring a 17p deletion.

  8. Neurotrophin-3 and FLT3 Tyrosine Kinase Receptor in Perinatal Life

    Directory of Open Access Journals (Sweden)

    Ariadne Malamitsi-Puchner

    2005-01-01

    Full Text Available Our aim is to determine—in 30 healthy full-term infants and their mothers—circulating levels of neurotrophin-3 (NT-3 (important for antenatal and postnatal brain development and implicated in the immune response and FLT3 tyrosine kinase receptor (FLT3 (controlling hematopoiesis and found in the nervous tissue, in the fetal and neonatal life. NT-3 levels, in contrast to FLT3 ones, increased significantly on the fourth postnatal day in relation to the low levels found in the mother, fetus, and day 1 neonate (P=.03, respectively. Maternal and umbilical NT3 levels positively correlated with respective FLT3 levels (P=.003 and P=.03. Circulating NT-3 levels increased in early neonatal life, possibly due to exposure to various stimuli soon after birth. FLT3 levels do not seem to behave accordingly, although these two substances probably synergize.

  9. Pyrrolo[2,3-b]pyridine derivatives as potent Bruton's tyrosine kinase inhibitors.

    Science.gov (United States)

    Zhao, Xinge; Huang, Wei; Wang, Yazhou; Xin, Minhang; Jin, Qiu; Cai, Jianfeng; Tang, Feng; Zhao, Yong; Xiang, Hua

    2015-08-01

    A series of pyrrolo[2,3-b]pyridine-based derivatives were designed as potent Bruton's tyrosine kinase (BTK) inhibitors by using a scaffold-hopping strategy. Structure-activity relationship studies identified five compounds (3n, 3p, 3q, 3r, and 3s) with IC50 of less than 10nM in BTK enzyme assay and five compounds (3m, 3n, 3o, 3p, and 3t) with IC50 of less than 20 nM in Ramos cell assay. As one of the most potent inhibitors, compound 3p exhibited superior activity to that of compound 1 (RN486) and pyrrolo[2,3-d]pyrimidine derivative 2 in both BTK enzymatic (IC50=6.0 nM) and cellular inhibition (IC50=14 nM) assays. In addition, 3p displayed favorable overall pharmacokinetic profiles compared with 1 and 2.

  10. 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.

  11. TREATMENT OF RENAL CARCINOMA IN A BINTURONG (ARCTICTIS BINTURONG) WITH NEPHRECTOMY AND A TYROSINE KINASE INHIBITOR.

    Science.gov (United States)

    Thompson, Kimberly A; Patterson, Jon; Fitzgerald, Scott D; Needle, David; Harrison, Tara

    2016-12-01

    A 13-yr-old female binturong ( Arctictis binturong ) presented with a 1 wk history of decreased appetite. The animal was thin, with hypercalcemia (calcium 12.2 mg/dl). A right renal mass was identified on ultrasound and removed via nephrectomy. Histopathology indicated a renal adenocarcinoma. Treatment with toceranib phosphate, a tyrosine-kinase inhibitor, was initiated and well tolerated by the animal. Four months after initial diagnosis radiographs indicated metastases to the lungs and the animal was euthanized. Necropsy revealed disseminated adenocarcinoma. Although treatment did not prevent metastasis, it was minimally invasive and well tolerated by the animal with minimal side effects. Review of records at the institution revealed that the cause of death for the primary case's dam and sire was disseminated renal carcinoma. These cases suggest that there may be a hereditary component to development of renal neoplasia in binturongs. Renal carcinoma should be considered an aggressive neoplasia in binturongs with a poor prognosis.

  12. Activation of TYRO3/AXL tyrosine kinase receptors in thyroid cancer.

    Science.gov (United States)

    Avilla, Elvira; Guarino, Valentina; Visciano, Carla; Liotti, Federica; Svelto, Maria; Krishnamoorthy, Gnanaprakasam; Franco, Renato; Melillo, Rosa Marina

    2011-03-01

    Thyroid cancer is the most common endocrine cancer, but its key oncogenic drivers remain undefined. In this study we identified the TYRO3 and AXL receptor tyrosine kinases as transcriptional targets of the chemokine CXCL12/SDF-1 in CXCR4-expressing thyroid cancer cells. Both receptors were constitutively expressed in thyroid cancer cell lines but not normal thyroid cells. AXL displayed high levels of tyrosine phosphorylation in most cancer cell lines due to constitutive expression of its ligand GAS6. In human thyroid carcinoma specimens, but not in normal thyroid tissues, AXL and GAS6 were often coexpressed. In cell lines expressing both receptors and ligand, blocking each receptor or ligand dramatically affected cell viability and decreased resistance to apoptotic stimuli. Stimulation of GAS6-negative cancer cells with GAS6 increased their proliferation and survival. Similarly, siRNA-mediated silencing of AXL inhibited cancer cell viability, invasiveness, and growth of tumor xenografts in nude mice. Our findings suggest that a TYRO3/AXL-GAS6 autocrine circuit sustains the malignant features of thyroid cancer cells and that targeting the circuit could offer a novel therapeutic approach in this cancer. ©2011 AACR.

  13. Activation of tyrosine kinase c-Abl contributes to α-synuclein–induced neurodegeneration

    Science.gov (United States)

    Lee, Su Hyun; Kim, Donghoon; Karuppagounder, Senthilkumar S.; Kumar, Manoj; Mao, Xiaobo; Shin, Joo Ho; Lee, Yunjong; Pletnikova, Olga; Troncoso, Juan C.; Dawson, Valina L.; Dawson, Ted M.; Ko, Han Seok

    2016-01-01

    Aggregation of α-synuclein contributes to the formation of Lewy bodies and neurites, the pathologic hallmarks of Parkinson disease (PD) and α-synucleinopathies. Although a number of human mutations have been identified in familial PD, the mechanisms that promote α-synuclein accumulation and toxicity are poorly understood. Here, we report that hyperactivity of the nonreceptor tyrosine kinase c-Abl critically regulates α-synuclein–induced neuropathology. In mice expressing a human α-synucleinopathy–associated mutation (hA53Tα-syn mice), deletion of the gene encoding c-Abl reduced α-synuclein aggregation, neuropathology, and neurobehavioral deficits. Conversely, overexpression of constitutively active c-Abl in hA53Tα-syn mice accelerated α-synuclein aggregation, neuropathology, and neurobehavioral deficits. Moreover, c-Abl activation led to an age-dependent increase in phosphotyrosine 39 α-synuclein. In human postmortem samples, there was an accumulation of phosphotyrosine 39 α-synuclein in brain tissues and Lewy bodies of PD patients compared with age-matched controls. Furthermore, in vitro studies show that c-Abl phosphorylation of α-synuclein at tyrosine 39 enhances α-synuclein aggregation. Taken together, this work establishes a critical role for c-Abl in α-synuclein–induced neurodegeneration and demonstrates that selective inhibition of c-Abl may be neuroprotective. This study further indicates that phosphotyrosine 39 α-synuclein is a potential disease indicator for PD and related α-synucleinopathies. PMID:27348587

  14. The c-Met tyrosine kinase inhibitor JNJ-38877605 causes renal toxicity through species-specific insoluble metabolite formation

    NARCIS (Netherlands)

    M.P. Lolkema (Martijn); H.H. Bohets (Hilde H.); H.-T. Arkenau (H.); A. Lampo (Ann); E. Barale (Erio); M.J.A. de Jonge (Maja); L. van Doorn (Leni); P. Hellemans (Peter); J.S. de Bono (Johann); F.A.L.M. Eskens (Ferry)

    2015-01-01

    textabstractPurpose: The receptor tyrosine kinase c-Met plays an important role in tumorigenesis and is a novel target for anticancer treatment. This phase I, first-in-human trial, explored safety, pharmacokinetics, pharmacodynamics, and initial antitumor activity of JNJ-38877605, a potent and

  15. Mutation pattern in the Bruton's tyrosine kinase gene in 26 unrelated patients with X-linked agammaglobulinemia

    DEFF Research Database (Denmark)

    Vorechovský, I; Luo, L; Hertz, Jens Michael

    1997-01-01

    Mutation pattern was characterized in the Bruton's tyrosine kinase gene (BTK) in 26 patients with X-linked agammaglobulinemia, the first described immunoglobulin deficiency, and was related to BTK expression. A total of 24 different mutations were identified. Most BTK mutations were found to resu...

  16. PROLACTIN-INDUCED TYROSINE PHOSPHORYLATION, ACTIVATION AND RECEPTOR ASSOCIATION OF FOCAL ADHESION KINASE (FAK) IN MAMMARY EPITHELIAL CELLS

    Science.gov (United States)

    Prolactin-Induced Tyrosine Phosphorylation, Activation and ReceptorAssociation of Focal Adhesion Kinase (FAK) in Mammary Epithelial Cells. Suzanne E. Fenton1 and Lewis G. Sheffield2. 1U.S. Environmental ProtectionAgency, MD-72, Research Triangle Park, NC 27711, and

  17. Myeloproliferative Neoplasms Associated with Mutation in JAK2V617F and Tyrosine Kinase Inhibitors as Therapeutic Strategy

    Directory of Open Access Journals (Sweden)

    Kaveh Tari

    2015-04-01

    Full Text Available MPNs including a heterogeneous group of clonal or oligoclonal hamtopathies characterized by proliferation and accumulation of mature myeloid cells. JAK2 tyrosine kinase mutation is the most common molecular lesion identified in 90% of cases. JAK2 is involved in EPO signaling pathway, and mutations in it lead to EPO-independent spontaneous phosphorylation. Most tyrosine kinase inhibitors (TKI are small molecules that compete with ATP for binding the ATP-binding site in tyrosine kinase domains, since ATP is a source of phosphate groups used by Tks to phosphorylate the target protein.there are many TKI agent that are studing for treatment of the MPNs with JAK2 tyrosine kinase mutation.the most important TKI drugs including CEP701, CYT387, LY2784544, SB1518, TG101348, XL019, INCB18424. Most important mechanism of them are reduse the splenomegaly, improvement of constitutional symptoms(improvement of bone marrow fibrosis and anemia. Although this drugs are useful but they have some side effect that common of them including Gastrointestinal disease (GI, diarrhea, nausea and vomiting, anemia, thrombocytopenia, thrombosis, leukocytosis, thrombocytosis, peripheral neuropathy, transient loss of blood pressure and lightheadedness.

  18. The Axl receptor tyrosine kinase confers an adverse prognostic influence in pancreatic cancer and represents a new therapeutic target

    NARCIS (Netherlands)

    Koorstra, Jan-Bart M.; Karikari, Collins A.; Feldmann, Georg; Bisht, Savita; Rojas, Pamela Leal; Offerhaus, G. Johan A.; Alvarez, Hector; Maitra, Anirban

    2009-01-01

    Background: Pancreatic cancer is a near uniformly lethal disease and a better understanding of the molecular basis of this malignancy may lead to improved therapeutics. The Axl receptor tyrosine kinase is implicated in cellular transformation and tumor progression, although its role in pancreatic

  19. Bmx tyrosine kinase has a redundant function downstream of angiopoietin and vascular endothelial growth factor receptors in arterial endothelium.

    Science.gov (United States)

    Rajantie, I; Ekman, N; Iljin, K; Arighi, E; Gunji, Y; Kaukonen, J; Palotie, A; Dewerchin, M; Carmeliet, P; Alitalo, K

    2001-07-01

    The Bmx gene, a member of the Tec tyrosine kinase gene family, is known to be expressed in subsets of hematopoietic and endothelial cells. In this study, mice were generated in which the first coding exon of the Bmx gene was replaced with the lacZ reporter gene by a knock-in strategy. The homozygous mice lacking Bmx activity were fertile and had a normal life span without an obvious phenotype. Staining of their tissues using beta-galactosidase substrate to assess the sites of Bmx expression revealed strong signals in the endothelial cells of large arteries and in the endocardium starting between days 10.5 and 12.5 of embryogenesis and continuing in adult mice, while the venular endothelium showed a weak signal only in the superior and inferior venae cavae. Of the five known endothelial receptor tyrosine kinases tested, activated Tie-2 induced tyrosyl phosphorylation of the Bmx protein and both Tie-2 and vascular endothelial growth factor receptor 1 (VEGFR-1) stimulated Bmx tyrosine kinase activity. Thus, the Bmx tyrosine kinase has a redundant role in arterial endothelial signal transduction downstream of the Tie-2 and VEGFR-1 growth factor receptors.

  20. Roles of mitochondrial Src tyrosine kinase and zinc in nitric oxide-induced cardioprotection against ischemia/reperfusion injury.

    Science.gov (United States)

    Zhang, Y; Xing, F; Zheng, H; Xi, J; Cui, X; Xu, Z

    2013-07-01

    While nitric oxide (NO) induces cardioprotection by targeting the mitochondrial permeability transition pore (mPTP), the precise mitochondrial signaling events that mediate the action of NO remain unclear. The purpose of this study was to test whether NO induces cardioprotection against ischemia/reperfusion by inhibiting oxidative stress through mitochondrial zinc and Src tyrosine kinase. The NO donor S-nitroso-N-acetyl penicillamine (SNAP) given before the onset of ischemia reduced cell death in rat cardiomyocytes subjected to simulated ischemia/reperfusion, and this was abolished by the zinc chelator N,N,N',N'-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) and the Src tyrosine kinase inhibitor PP2. SNAP also prevented loss of mitochondrial membrane potential (ΔΨm) at reperfusion, an effect that was blocked by TPEN and PP2. SNAP increased mitochondrion-free zinc upon reperfusion and enhanced mitochondrial Src phosphorylation in a zinc-dependent manner. SNAP inhibited both mitochondrial complex I activity and mitochondrial reactive oxygen species (ROS) generation at reperfusion through zinc and Src tyrosine kinase. Finally, the anti-infarct effect of SNAP was abrogated by TPEN and PP2 applied at reperfusion in isolated rat hearts. In conclusion, NO induces cardioprotection at reperfusion by targeting mitochondria through attenuation of oxidative stress resulted from the inhibition of complex I at reperfusion. Activation of mitochondrial Src tyrosine kinase by zinc may account for the inhibition of complex I.

  1. The receptor tyrosine kinase FGFR4 negatively regulates NF-kappaB signaling.

    Directory of Open Access Journals (Sweden)

    Kristine A Drafahl

    Full Text Available BACKGROUND: NFκB signaling is of paramount importance in the regulation of apoptosis, proliferation, and inflammatory responses during human development and homeostasis, as well as in many human cancers. Receptor Tyrosine Kinases (RTKs, including the Fibroblast Growth Factor Receptors (FGFRs are also important in development and disease. However, a direct relationship between growth factor signaling pathways and NFκB activation has not been previously described, although FGFs have been known to antagonize TNFα-induced apoptosis. METHODOLOGY/PRINCIPAL FINDINGS: Here, we demonstrate an interaction between FGFR4 and IKKβ (Inhibitor of NFκB Kinase β subunit, an essential component in the NFκB pathway. This novel interaction was identified utilizing a yeast two-hybrid screen [1] and confirmed by coimmunoprecipitation and mass spectrometry analysis. We demonstrate tyrosine phosphorylation of IKKβ in the presence of activated FGFR4, but not kinase-dead FGFR4. Following stimulation by TNFα (Tumor Necrosis Factor α to activate NFκB pathways, FGFR4 activation results in significant inhibition of NFκB signaling as measured by decreased nuclear NFκB localization, by reduced NFκB transcriptional activation in electophoretic mobility shift assays, and by inhibition of IKKβ kinase activity towards the substrate GST-IκBα in in vitro assays. FGF19 stimulation of endogenous FGFR4 in TNFα-treated DU145 prostate cancer cells also leads to a decrease in IKKβ activity, concomitant reduction in NFκB nuclear localization, and reduced apoptosis. Microarray analysis demonstrates that FGF19 + TNFα treatment of DU145 cells, in comparison with TNFα alone, favors proliferative genes while downregulating genes involved in apoptotic responses and NFκB signaling. CONCLUSIONS/SIGNIFICANCE: These results identify a compelling link between FGFR4 signaling and the NFκB pathway, and reveal that FGFR4 activation leads to a negative effect on NFκB signaling

  2. Mapping C-terminal transactivation domains of the nuclear HER family receptor tyrosine kinase HER3.

    Science.gov (United States)

    Brand, Toni M; Iida, Mari; Luthar, Neha; Wleklinski, Matthew J; Starr, Megan M; Wheeler, Deric L

    2013-01-01

    Nuclear localized HER family receptor tyrosine kinases (RTKs) have been observed in primary tumor specimens and cancer cell lines for nearly two decades. Inside the nucleus, HER family members (EGFR, HER2, and HER3) have been shown to function as co-transcriptional activators for various cancer-promoting genes. However, the regions of each receptor that confer transcriptional potential remain poorly defined. The current study aimed to map the putative transactivation domains (TADs) of the HER3 receptor. To accomplish this goal, various intracellular regions of HER3 were fused to the DNA binding domain of the yeast transcription factor Gal4 (Gal4DBD) and tested for their ability to transactivate Gal4 UAS-luciferase. Results from these analyses demonstrated that the C-terminal domain of HER3 (CTD, amino acids distal to the tyrosine kinase domain) contained potent transactivation potential. Next, nine HER3-CTD truncation mutants were constructed to map minimal regions of transactivation potential using the Gal4 UAS-luciferase based system. These analyses identified a bipartite region of 34 (B₁) and 27 (B₂) amino acids in length that conferred the majority of HER3's transactivation potential. Next, we identified full-length nuclear HER3 association and regulation of a 122 bp region of the cyclin D1 promoter. To understand how the B₁ and B₂ regions influenced the transcriptional functions of nuclear HER3, we performed cyclin D1 promoter-luciferase assays in which HER3 deleted of the B₁ and B₂ regions was severely hindered in regulating this promoter. Further, the overexpression of HER3 enhanced cyclin D1 mRNA expression, while HER3 deleted of its identified TADs was hindered at doing so. Thus, the ability for HER3 to function as a transcriptional co-activator may be dependent on specific C-terminal TADs.

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

    Science.gov (United States)

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

    2016-06-03

    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.

  4. Hepatitis B Virus Reactivation during Treatment with Multi-Tyrosine Kinase Inhibitor for Hepatocellular Carcinoma

    Directory of Open Access Journals (Sweden)

    Satoshi Shiba

    2012-09-01

    Full Text Available Hepatitis B virus (HBV reactivation is well documented in individuals with cancer who receive certain cytotoxic or immunosuppressive therapies including rituximab treatment. As a general rule, the risk is greatest upon withdrawal of chemotherapy. The risk ranges from approximately 20 to 50% among HBsAg-positive carriers. A 67-year-old man was diagnosed with inoperable multiple hepatocellular carcinoma accompanied by an increase in alpha-fetoprotein and protein induced by vitamin K absence or antagonist II level. Eighteen weeks after starting on the oral multi-tyrosine kinase inhibitor TSU-68, laboratory investigations showed a substantial increase in serum transaminase levels (AST: 302 IU/l; ALT: 324 IU/l and an elevation of the HBV-DNA level (6.9 log copies/ml. The diagnosis was that the cause of the acute hepatitis was HBV reactivation and we immediately administered entecavir. Two months after the initiation of daily entecavir treatment, laboratory findings showed that the serum levels of transaminases and ALP had improved (AST: 18 IU/l; ALT: 10 IU/l; ALP: 197 U/l. When the HBV markers were examined 4 months later, they were altered: HBeAg was negative and HBeAb was positive. Entecavir treatment was discontinued after 6 months. Although reactivation with rituximab has been reported, reactivation with a tyrosine kinase inhibitor is extremely unusual in a patient who is HBsAg negative but anti-HBc positive. This is the first report describing HBV reactivation with an increasing HBV-DNA level in a HBsAg-negative/HBcAb-positive/HBsAb-positive patient who was treated with TSU-68 for hepatocellular carcinoma.

  5. Ligand-based receptor tyrosine kinase partial agonists: New paradigm for cancer drug discovery?

    Science.gov (United States)

    Riese, David J.

    2010-01-01

    Introduction Receptor tyrosine kinases (RTKs) are validated targets for oncology drug discovery and several RTK antagonists have been approved for the treatment of human malignancies. Nonetheless, the discovery and development of RTK antagonists has lagged behind the discovery and development of agents that target G-protein coupled receptors. In part, this is because it has been difficult to discover analogs of naturally-occurring RTK agonists that function as antagonists. Areas covered Here we describe ligands of ErbB receptors that function as partial agonists for these receptors, thereby enabling these ligands to antagonize the activity of full agonists for these receptors. We provide insights into the mechanisms by which these ligands function as antagonists. We discuss how information concerning these mechanisms can be translated into screens for novel small molecule- and antibody-based antagonists of ErbB receptors and how such antagonists hold great potential as targeted cancer chemotherapeutics. Expert opinion While there have been a number of important key findings into this field, the identification of the structural basis of ligand functional specificity is still of the greatest importance. While it is true that, with some notable exceptions, peptide hormones and growth factors have not proven to be good platforms for oncology drug discovery; addressing the fundamental issues of antagonistic partial agonists for receptor tyrosine kinases has the potential to steer oncology drug discovery in new directions. Mechanism based approaches are now emerging to enable the discovery of RTK partial agonists that may antagonize both agonist-dependent and –independent RTK signaling and may hold tremendous promise as targeted cancer chemotherapeutics. PMID:21532939

  6. Oral administration of Bruton's tyrosine kinase inhibitors impairs GPVI-mediated platelet function.

    Science.gov (United States)

    Rigg, Rachel A; Aslan, Joseph E; Healy, Laura D; Wallisch, Michael; Thierheimer, Marisa L D; Loren, Cassandra P; Pang, Jiaqing; Hinds, Monica T; Gruber, András; McCarty, Owen J T

    2016-03-01

    The Tec family kinase Bruton's tyrosine kinase (Btk) plays an important signaling role downstream of immunoreceptor tyrosine-based activation motifs in hematopoietic cells. Mutations in Btk are involved in impaired B-cell maturation in X-linked agammaglobulinemia, and Btk has been investigated for its role in platelet activation via activation of the effector protein phospholipase Cγ2 downstream of the platelet membrane glycoprotein VI (GPVI). Because of its role in hematopoietic cell signaling, Btk has become a target in the treatment of chronic lymphocytic leukemia and mantle cell lymphoma; the covalent Btk inhibitor ibrutinib was recently approved by the US Food and Drug Administration for treatment of these conditions. Antihemostatic events have been reported in some patients taking ibrutinib, although the mechanism of these events remains unknown. We sought to determine the effects of Btk inhibition on platelet function in a series of in vitro studies of platelet activation, spreading, and aggregation. Our results show that irreversible inhibition of Btk with two ibrutinib analogs in vitro decreased human platelet activation, phosphorylation of Btk, P-selectin exposure, spreading on fibrinogen, and aggregation under shear flow conditions. Short-term studies of ibrutinib analogs administered in vivo also showed abrogation of platelet aggregation in vitro, but without measurable effects on plasma clotting times or on bleeding in vivo. Taken together, our results suggest that inhibition of Btk significantly decreased GPVI-mediated platelet activation, spreading, and aggregation in vitro; however, prolonged bleeding was not observed in a model of bleeding. Copyright © 2016 the American Physiological Society.

  7. EGFR tyrosine kinase inhibition radiosensitizes and induces apoptosis in malignant glioma and childhood ependymoma xenografts.

    Science.gov (United States)

    Geoerger, Birgit; Gaspar, Nathalie; Opolon, Paule; Morizet, Jackie; Devanz, Pauline; Lecluse, Yann; Valent, Alexander; Lacroix, Ludovic; Grill, Jacques; Vassal, Gilles

    2008-07-01

    Malignant gliomas and childhood ependymomas have a high rate of treatment failure. Epidermal growth factor receptor (EGFR) activation has been implicated in the tumorigenesis and radioresistance of many cancers, including brain tumors. Therefore, combining EGFR targeting with irradiation is a potentially attractive therapeutic option. We evaluated the tyrosine kinase inhibitor gefitinib for its antitumor activity and potential to radio-sensitize in vivo in two xenograft models: an EGFR amplified glioma and an EGFR expressing ependymoma, both derived from primary tumors. When administered at 100 mg/kg for 5 consecutive days, gefitinib-induced partial tumor regression in all treated EGFR amplified IGRG88 glioma xenografts. The addition of 1 Gy of irradiation prior to gefitinib administration resulted in 5 complete and 4 partial regressions for the 9 treated tumors as well as a significant tumor growth delay of 33 days for the combined treatment compared to 19 days for each therapy alone, suggesting additive antitumor activity. Tumor regression was associated with inhibition of AKT and MAPK pathways by gefitinib. In contrast, the ependymoma IGREP83 was sensitive to irradiation, but remained resistant to gefitinib. Combined treatment was associated with inhibition of radiation-induced MAPK phosphorylation and significant induction of apoptotic cell death though radiation-induced AKT phosphorylation was maintained. Depending on the scheduling of both therapies, a trend towards superior antitumor activity was observed with combined treatment. Thus, EGFR targeting through tyrosine kinase inhibition appears to be a promising new approach in the treatment of EGFR-driven glioma, particularly in combination with radiation therapy. (c) 2008 Wiley-Liss, Inc.

  8. Fasting potentiates the anticancer activity of tyrosine kinase inhibitors by strengthening MAPK signaling inhibition.

    Science.gov (United States)

    Caffa, Irene; D'Agostino, Vito; Damonte, Patrizia; Soncini, Debora; Cea, Michele; Monacelli, Fiammetta; Odetti, Patrizio; Ballestrero, Alberto; Provenzani, Alessandro; Longo, Valter D; Nencioni, Alessio

    2015-05-20

    Tyrosine kinase inhibitors (TKIs) are now the mainstay of treatment in many types of cancer. However, their benefit is frequently short-lived, mandating the search for safe potentiation strategies. Cycles of fasting enhance the activity of chemo-radiotherapy in preclinical cancer models and dietary approaches based on fasting are currently explored in clinical trials. Whether combining fasting with TKIs is going to be potentially beneficial remains unknown. Here we report that starvation conditions increase the ability of commonly administered TKIs, including erlotinib, gefitinib, lapatinib, crizotinib and regorafenib, to block cancer cell growth, to inhibit the mitogen-activated protein kinase (MAPK) signaling pathway and to strengthen E2F-dependent transcription inhibition. In cancer xenografts models, both TKIs and cycles of fasting slowed tumor growth, but, when combined, these interventions were significantly more effective than either type of treatment alone. In conclusion, cycles of fasting or of specifically designed fasting-mimicking diets should be evaluated in clinical studies as a means to potentiate the activity of TKIs in clinical use.

  9. Imipramine protects retinal ganglion cells from oxidative stress through the tyrosine kinase receptor B signaling pathway

    Institute of Scientific and Technical Information of China (English)

    Ming-lei Han; Guo-hua Liu; Jin Guo; Shu-juan Yu; Jing Huang

    2016-01-01

    Retinal ganglion cell (RGC) degeneration is irreversible in glaucoma and tyrosine kinase receptor B (TrkB)-associated signaling pathways have been implicated in the process. In this study, we attempted to examine whether imipramine, a tricyclic antidepressant, may protect hydrogen peroxide (H2O2)-induced RGC degeneration through the activation of the TrkB pathway in RGC-5 cell lines. RGC-5 cell lines were pre-treated with imipramine 30 minutes before exposure to H2O2. Western blot assay showed that in H2O2-damaged RGC-5 cells, imipramine activated TrkB pathways through extracellular signal-regulated protein kinase/TrkB phosphorylation. TUNEL staining assay also demonstrated that imipramine ameliorated H2O2-induced apoptosis in RGC-5 cells. Finally, TrkB-IgG intervention was able to reverse the protective effect of imipramine on H2O2-induced RGC-5 apoptosis. Imipramine therefore protects RGCs from oxidative stress-induced apoptosis through the TrkB signaling pathway.

  10. Targeting Bruton's tyrosine kinase with ibrutinib in B-cell malignancies.

    Science.gov (United States)

    Wang, Y; Zhang, L L; Champlin, R E; Wang, M L

    2015-05-01

    The B-cell receptor signaling pathway, which is critical to the development and maturation of normal B-cells, is emerging as an attractive therapeutic target in B-cell malignancies. Ibrutinib is a potent irreversible inhibitor of Bruton's tyrosine kinase (Btk), a key kinase important for signal transduction in the B-cell receptor (BCR) pathway. In preclinical studies, ibrutinib potently bound to Btk, inhibited BCR signaling, and decreased tumor cell proliferation and survival in many B-cell malignancy models. Excellent safety and efficacy data in clinical trials have led to US Food and Drug Administration (FDA) approval of ibrutinib for previously treated mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL), as well as CLL with 17p deletion. Ongoing clinical studies have also demonstrated great potency of ibrutinib in treating other types of non-Hodgkin's lymphoma (NHL), including diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and Waldenström's macroglobulinemia (WM). Combination of ibrutinib with chemoimmunotherapy and other promising novel agents in B-cell malignancy therapy has also been under clinical investigation. © 2015 American Society for Clinical Pharmacology and Therapeutics.

  11. Spleen Tyrosine Kinase Regulates AP-1 Dependent Transcriptional Response to Minimally Oxidized LDL

    Science.gov (United States)

    Choi, Soo-Ho; Wiesner, Philipp; Almazan, Felicidad; Kim, Jungsu; Miller, Yury I.

    2012-01-01

    Oxidative modification of low-density lipoprotein (LDL) turns it into an endogenous ligand recognized by pattern-recognition receptors. We have demonstrated that minimally oxidized LDL (mmLDL) binds to CD14 and mediates TLR4/MD-2-dependent responses in macrophages, many of which are MyD88-independent. We have also demonstrated that the mmLDL activation leads to recruitment of spleen tyrosine kinase (Syk) to TLR4 and TLR4 and Syk phosphorylation. In this study, we produced a macrophage-specific Syk knockout mouse and used primary Syk−/− macrophages in our studies. We demonstrated that Syk mediated phosphorylation of ERK1/2 and JNK, which in turn phosphorylated c-Fos and c-Jun, respectively, as assessed by an in vitro kinase assay. c-Jun phosphorylation was also mediated by IKKε. c-Jun and c-Fos bound to consensus DNA sites and thereby completed an AP-1 transcriptional complex and induced expression of CXCL2 and IL-6. These results suggest that Syk plays a key role in TLR4-mediated macrophage responses to host-generated ligands, like mmLDL, with subsequent activation of an AP-1 transcription program. PMID:22384232

  12. Deletion of the endothelial Bmx tyrosine kinase decreases tumor angiogenesis and growth.

    Science.gov (United States)

    Holopainen, Tanja; López-Alpuche, Vanessa; Zheng, Wei; Heljasvaara, Ritva; Jones, Dennis; He, Yun; Tvorogov, Denis; D'Amico, Gabriela; Wiener, Zoltan; Andersson, Leif C; Pihlajaniemi, Taina; Min, Wang; Alitalo, Kari

    2012-07-15

    Bmx, [corrected] also known as Etk, is a member of the Tec family of nonreceptor tyrosine kinases. Bmx is expressed mainly in arterial endothelia and in myeloid hematopoietic cells. Bmx regulates ischemia-mediated arteriogenesis and lymphangiogenesis, but its role in tumor angiogenesis is not known. In this study, we characterized the function of Bmx in tumor growth using both Bmx knockout and transgenic mice. Isogenic colon, lung, and melanoma tumor xenotransplants showed reductions in growth and tumor angiogenesis in Bmx gene-deleted ((-/-)) mice, whereas developmental angiogenesis was not affected. In addition, growth of transgenic pancreatic islet carcinomas and intestinal adenomas was also slower in Bmx(-/-) mice. Knockout mice showed high levels of Bmx expression in endothelial cells of tumor-associated and peritumoral arteries. Moreover, endothelial cells lacking Bmx showed impaired phosphorylation of extracellular signal-regulated kinase (Erk) upon VEGF stimulation, indicating that Bmx contributes to the transduction of vascular endothelial growth factor signals. In transgenic mice overexpressing Bmx in epidermal keratinocytes, tumors induced by a two-stage chemical skin carcinogenesis treatment showed increased growth and angiogenesis. Our findings therefore indicate that Bmx activity contributes to tumor angiogenesis and growth.

  13. Fyn tyrosine kinase regulates oligodendroglial cell development but is not required for morphological differentiation of oligodendrocytes.

    Science.gov (United States)

    Sperber, B R; McMorris, F A

    2001-02-15

    The non-receptor protein tyrosine kinase Fyn, which is a member of the Src family of kinases, has been shown to be essential for normal myelination and has been suggested to play a role in oligodendrocyte development. However, oligodendrocyte development has not been studied directly in cells lacking Fyn. Additionally, because Fyn is expressed in neurons as well as oligodendrocytes, it is possible that normal myelination requires Fyn expression in neurons but not in oligodendrocytes. To address these issues, we analyzed the development of oligodendrocytes in neuron-free glial cell cultures from fyn(-/-) mice that express no Fyn protein. We observed that oligodendrocytes develop to the stage where they elaborate an extensive network of membranous processes and express the antigenic components of mature oligodendrocytes in the complete absence of Fyn. However, as compared with fyn(+/+) controls, fewer oligodendroglia developed in fyn(-/-) cell cultures, and a smaller proportion of them matured to the stage characterized by a high degree of morphological complexity. In addition, we found that insulin-like growth factor-I, a potent stimulator of oligodendrocyte development, failed to stimulate morphological maturation of fyn(-/-) oligodendroglia. The pyrazolopyrimidine PP2, believed to be a selective inhibitor of Fyn, did not prevent the development of morphologically complex oligodendrocytes. Unexpectedly, however, it was toxic to both fyn(+/+) and fyn(-/-) glial cells, indicating that this class of inhibitors can have significant effects that are independent of Fyn.

  14. The tyrosine kinase Stitcher activates Grainy head and epidermal wound healing in Drosophila.

    Science.gov (United States)

    Wang, Shenqiu; Tsarouhas, Vasilios; Xylourgidis, Nikos; Sabri, Nafiseh; Tiklová, Katarína; Nautiyal, Naumi; Gallio, Marco; Samakovlis, Christos

    2009-07-01

    Epidermal injury initiates a cascade of inflammation, epithelial remodelling and integument repair at wound sites. The regeneration of the extracellular barrier and damaged tissue repair rely on the precise orchestration of epithelial responses triggered by the injury. Grainy head (Grh) transcription factors induce gene expression to crosslink the extracellular barrier in wounded flies and mice. However, the activation mechanisms and functions of Grh factors in re-epithelialization remain unknown. Here we identify stitcher (stit), a new Grh target in Drosophila melanogaster. stit encodes a Ret-family receptor tyrosine kinase required for efficient epidermal wound healing. Live imaging analysis reveals that Stit promotes actin cable assembly during wound re-epithelialization. Stit activation also induces extracellular signal-regulated kinase (ERK) phosphorylation along with the Grh-dependent expression of stit and barrier repair genes at the wound sites. The transcriptional stimulation of stit on injury triggers a positive feedback loop increasing the magnitude of epithelial responses. Thus, Stit activation upon wounding coordinates cytoskeletal rearrangements and the level of Grh-mediated transcriptional wound responses.

  15. Imipramine protects retinal ganglion cells from oxidative stress through the tyrosine kinase receptor B signaling pathway

    Directory of Open Access Journals (Sweden)

    Ming-lei Han

    2016-01-01

    Full Text Available Retinal ganglion cell (RGC degeneration is irreversible in glaucoma and tyrosine kinase receptor B (TrkB-associated signaling pathways have been implicated in the process. In this study, we attempted to examine whether imipramine, a tricyclic antidepressant, may protect hydrogen peroxide (H 2 O 2 -induced RGC degeneration through the activation of the TrkB pathway in RGC-5 cell lines. RGC-5 cell lines were pre-treated with imipramine 30 minutes before exposure to H 2 O 2 . Western blot assay showed that in H 2 O 2 -damaged RGC-5 cells, imipramine activated TrkB pathways through extracellular signal-regulated protein kinase/TrkB phosphorylation. TUNEL staining assay also demonstrated that imipramine ameliorated H 2 O 2 -induced apoptosis in RGC-5 cells. Finally, TrkB-IgG intervention was able to reverse the protective effect of imipramine on H 2 O 2 -induced RGC-5 apoptosis. Imipramine therefore protects RGCs from oxidative stress-induced apoptosis through the TrkB signaling pathway.

  16. 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.

  17. The pathobiology of the oncogenic tyrosine kinase NPM-ALK: a brief update.

    Science.gov (United States)

    Lai, Raymond; Ingham, Robert J

    2013-04-01

    Extensive research has been carried out in the past two decades to study the pathobiology of nucleophosmin-anaplastic lymphoma kinase (NPM-ALK), which is an oncogenic fusion protein found exclusively in a specific type of T-cell lymphoid malignancy, namely ALK-positive anaplastic large cell lymphoma. Results from these studies have provided highly useful insights into the mechanisms by which a constitutively tyrosine kinase, such as NPM-ALK, promotes tumorigenesis. Several previous publications have comprehensively summarized the advances in this field. In this review, we provide readers with a brief update on specific areas of NPM-ALK pathobiology. In the first part, the NPM-ALK/signal transducer and activator of transcription 3 (STAT3) signaling axis is discussed, with an emphasis on the existence of multiple biochemical defects that have been shown to amplify the oncogenic effects of this signaling axis. Specifically, findings regarding JAK3, SHP1 and the stimulatory effects of several cytokines including interleukin (IL)-9, IL-21 and IL-22 are summarized. New concepts stemming from recent observations regarding the functional interactions among the NPM-ALK/STAT3 axis, β catenin and glycogen synthase kinase 3β will be postulated. Lastly, new mechanisms by which the NPM-ALK/STAT3 axis promotes tumorigenesis, such as its modulations of Twist1, hypoxia-induced factor 1α, CD274, will be described. In the second part, we summarize recent data generated by mass spectrometry studies of NPM-ALK, and use MSH2 and heat shock proteins as examples to illustrate the use of mass spectrometry data in stimulating new research in this field. In the third part, the evolving field of microRNA in the context of NPM-ALK biology is discussed.

  18. Spleen tyrosine kinase (SYK) is a potential target for the treatment of cutaneous lupus erythematosus patients.

    Science.gov (United States)

    Braegelmann, Christine; Hölzel, Michael; Ludbrook, Valerie; Dickson, Marion; Turan, Nil; Ferring-Schmitt, Sandra; Sternberg, Sonja; Bieber, Thomas; Kuhn, Annegret; Wenzel, Joerg

    2016-05-01

    Spleen tyrosine kinase (SYK) is a protein kinase involved in cell proliferation and the regulation of inflammatory pathways. Due to the increasing evidence that kinase inhibitors have potential as specific anti-inflammatory drugs, we have investigated the potential for SYK inhibition as a therapeutic target in autoimmune diseases, particularly cutaneous lupus erythematosus (CLE). Skin samples of patients with different CLE subtypes and appropriate controls were analysed for the expression of SYK and SYK-associated pro-inflammatory mediators via gene expression analysis and immunohistochemistry. The functional role of SYK in keratinocytes was investigated in vitro, using LE-typical pro-inflammatory stimuli and a selective inhibitor of SYK. SYK-associated genes are strongly upregulated in CLE skin lesions. Importantly, phosphorylated SYK (pSYK) is strongly expressed by several immune cell types and also keratinocytes in CLE skin. In vitro, immunostimulatory nucleic acids are capable of inducing SYK phosphorylation in keratinocytes leading to the induction of pro-inflammatory cytokines, while small-molecule SYK inhibition decreases the expression of these proteins. The results demonstrate that pSYK is expressed by immune cells and keratinocytes in skin lesions of CLE patients. LE-typical stimuli induce the expression of pSYK in vitro. Small-molecule SYK inhibition leads to a reduction of pSYK expression and downregulation of pro-inflammatory cytokines in keratinocytes. We therefore believe that pSYK provides a potential future drug target for the treatment of patients who suffer from CLE and related skin disorders. Specifically, our study reveals evidence supporting the use of topical SYK inhibitors in treating lupus.

  19. Current Status of Bruton's Tyrosine Kinase Inhibitor Development and Use in B-Cell Malignancies.

    Science.gov (United States)

    Aw, Andrew; Brown, Jennifer R

    2017-07-01

    The B-cell receptor (BCR) pathway plays an important role in the survival, proliferation and trafficking of cancer cells in a variety of B-cell malignancies. Recently, a number of agents have been developed to target various components of the BCR pathway. One such target is Bruton's tyrosine kinase (BTK), a Tec family kinase member found near the cell membrane that is involved in upstream BCR signaling. The biological function of BTK in several B-cell lymphoid malignancies has led to the development of the oral BTK inhibitor ibrutinib. In chronic lymphocytic leukemia (CLL), ibrutinib has demonstrated durable clinical responses in relapsed/refractory (R/R) patients, including those with the high-risk del(17p) cytogenetic abnormality. These findings have paved the way for trials evaluating ibrutinib in previously untreated CLL patients, and also in combination with chemoimmunotherapy or other novel agents. Durable clinical responses have also been demonstrated in mantle cell lymphoma (MCL) and Waldenström's macroglobulinemia (WM) patients treated with ibrutinib. Ibrutinib is generally well tolerated, although current follow-up remains short and patients of advanced age are more likely to discontinue treatment for toxicity. Treatment-specific side effects such as bleeding and atrial fibrillation may, at least partly, be related to off-target inhibition of non-BTK kinases. Studies evaluating other potential indications for BTK inhibition are ongoing, including in post-allogeneic hematopoietic stem cell transplant patients for whom ibrutinib may be effective in modulating graft-versus-host disease. Combination trials of ibrutinib with venetoclax, a Bcl-2 inhibitor, are underway and are supported by sound preclinical rationale. Several next-generation BTK inhibitors are under development with the goal of decreasing treatment-related toxicity and resistance.

  20. The tyrosine 343 residue of nucleophosmin (NPM)-anaplastic lymphoma kinase (ALK) is important for its interaction with SHP1, a cytoplasmic tyrosine phosphatase with tumor suppressor functions.

    Science.gov (United States)

    Hegazy, Samar A; Wang, Peng; Anand, Mona; Ingham, Robert J; Gelebart, Pascal; Lai, Raymond

    2010-06-25

    The cytoplasmic tyrosine phosphatase SHP1 has been shown to inhibit the oncogenic fusion protein nucleophosmin (NPM)-anaplastic lymphoma kinase (ALK), and loss of SHP1 contributes to NPM-ALK-mediated tumorigenesis. In this study, we aimed to further understand how SHP1 interacts and regulates NPM-ALK. We employed an in vitro model in which GP293 cells were transfected with various combinations of NPM-ALK (or mutants) and SHP1 (or mutants) expression vectors. We found that SHP1 co-immunoprecipitated with NPM-ALK, but not the enzymatically inactive NPM-ALK(K210R) mutant, or the mutant in which all three functionally important tyrosine residues (namely, Tyr(338), Tyr(342), and Tyr(343)) in the kinase activation loop (KAL) of ALK were mutated. Interestingly, whereas mutation of Tyr(338) or Tyr(342) did not result in any substantial change in the NPM-ALK/SHP1 binding (assessed by co-immunoprecipitation), mutation of Tyr(343) abrogated this interaction. Furthermore, the NPM-ALK/SHP1 binding was readily detectable when each of the remaining 8 tyrosine residues known to be phosphorylated were mutated. Although the expression of SHP1 effectively reduced the level of tyrosine phosphorylation of NPM-ALK, it did not affect that of the NPM-ALK(Y343F) mutant. In soft agar clonogenic assay, SHP1 expression significantly reduced the tumorigenicity of NPM-ALK but not that of NPM-ALK(Y343F). In conclusion, we identified Tyr(343) of NPM-ALK as the crucial site for mediating the NPM-ALK/SHP1 interaction. Our results also support the notion that the tumor suppressor effects of SHP1 on NPM-ALK are dependent on its ability to bind to this oncogenic protein.

  1. The tyrosine kinase receptor ROR1 is constitutively phosphorylated in chronic lymphocytic leukemia (CLL cells.

    Directory of Open Access Journals (Sweden)

    Mohammad Hojjat-Farsangi

    Full Text Available Phosphorylation of receptor tyrosine kinases (RTKs has a key role in cellular functions contributing to the malignant phenotype of tumor cells. We and others have previously demonstrated that RTK ROR1 is overexpressed in chronic lymphocytic leukemia (CLL. Silencing siRNA downregulated ROR1 and induced apoptosis of CLL cells. In the present study we analysed ROR1 isoforms and the phosphorylation pattern in CLL cells (n=38 applying western blot and flow-cytometry using anti-ROR1 antibodies and an anti-phospho-ROR1 antibody against the TK domain. Two major ROR1 bands with the size of 105 and 130 kDa respectively were identified, presumably representing unglycosylated (immature and glycosylated (mature ROR1 respectively as well as a 260 kDa band which may represent dimerized ROR1. A ROR1 band of 64 kDa that may correspond to a C-terminal fragment was also noted, present only in the nucleus. The 105 kDa ROR1 isoform was more frequently expressed in non-progressive as compared to progressive CLL patients (p=0.03. The 64, 105, 130 and 260 kDa bands were constitutively phosphorylated both at tyrosine and serine residues. Phosphorylation intensity of the mature (130 kDa isoform was significantly higher in progressive than in non-progressive disease (p<0.001. Incubation of CLL cells with a mouse anti-ROR1 KNG or an anti-ROR1 CRD mAb respectively induced dephosphorylation of ROR1 before entering apoptosis. In conclusion CLL cells expressed different isoforms of ROR1 which were constitutively phosphorylated. The mature, phosphorylated ROR1 isoform was associated with a progressive disease stage. Targeting ROR1 by mAbs induced specific dephosphorylation and leukemic cell death. ROR1 might be an interesting therapeutic target.

  2. 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.

  3. Bruton's Tyrosine Kinase Small Molecule Inhibitors Induce a Distinct Pancreatic Toxicity in Rats.

    Science.gov (United States)

    Erickson, Rebecca I; Schutt, Leah K; Tarrant, Jacqueline M; McDowell, Michelle; Liu, Lichuan; Johnson, Adam R; Lewin-Koh, Sock-Cheng; Hedehus, Maj; Ross, Jed; Carano, Richard A D; Staflin, Karin; Zhong, Fiona; Crawford, James J; Zhong, Shelly; Reif, Karin; Katewa, Arna; Wong, Harvey; Young, Wendy B; Dambach, Donna M; Misner, Dinah L

    2017-01-01

    Bruton's tyrosine kinase (BTK) is a member of the Tec family of cytoplasmic tyrosine kinases involved in B-cell and myeloid cell signaling. Small molecule inhibitors of BTK are being investigated for treatment of several hematologic cancers and autoimmune diseases. GDC-0853 ((S)-2-(3'-(hydroxymethyl)-1-methyl-5-((5-(2-methyl-4-(oxetan-3-yl)piperazin-1-yl)pyridin-2-yl)amino)-6-oxo-1,6-dihydro-[3,4'-bipyridin]-2'-yl)-7,7-dimethyl-3,4,7,8-tetrahydro-2H-cyclopenta[4,5]pyrrolo[1,2-a]pyrazin-1(6H)-one) is a selective and reversible oral small-molecule BTK inhibitor in development for the treatment of rheumatoid arthritis and systemic lupus erythematosus. In Sprague-Dawley (SD) rats, administration of GDC-0853 and other structurally diverse BTK inhibitors for 7 days or longer caused pancreatic lesions consisting of multifocal islet-centered hemorrhage, inflammation, fibrosis, and pigment-laden macrophages with adjacent lobular exocrine acinar cell atrophy, degeneration, and inflammation. Similar findings were not observed in mice or dogs at much higher exposures. Hemorrhage in the peri-islet vasculature emerged between four and seven daily doses of GDC-0853 and was histologically similar to spontaneously occurring changes in aging SD rats. This suggests that GDC-0853 could exacerbate a background finding in younger animals. Glucose homeostasis was dysregulated following a glucose challenge; however, this occurred only after 28 days of administration and was not directly associated with onset or severity of pancreatic lesions. There were no changes in other common serum biomarkers assessing endocrine and exocrine pancreatic function. Additionally, these lesions were not readily detectable via Doppler ultrasound, computed tomography, or magnetic resonance imaging. Our results indicate that pancreatic lesions in rats are likely a class effect of BTK inhibitors, which may exacerbate an islet-centered pathology that is unlikely to be relevant to humans. Copyright © 2016 by

  4. Axl receptor tyrosine kinase is a novel target of apigenin for the inhibition of cell proliferation.

    Science.gov (United States)

    Kim, Kyung-Chan; Choi, Eun-Ha; Lee, Chuhee

    2014-08-01

    The Axl receptor tyrosine kinase (RTK), along with Tyro 3 and Mer, belongs to the TAM subfamily that promotes survival, stimulates proliferation and/or inhibits apoptosis. In various types of human cancer, including breast, lung and prostate cancer, Axl expression is increased and correlates with an advanced clinical stage. In this study, we examined whether apigenin has an effect on Axl expression, which in turn can affect cell proliferation. The treatment of the non‑small cell lung cancer (NSCLC) cells, A549 and H460, with apigenin decreased Axl mRNA and protein expression in a dose‑dependent manner. Axl promoter activity was also inhibited by apigenin, indicating that apigenin suppressed Axl expression at the transcriptional level. Upon treatment with apigenin, the viability of both the A549 and H460 cells was gradually decreased and the anti-proliferative effects were further confirmed by the dose‑dependent decrease in the clonogenic ability of the apigenin‑treated cells. Subsequently, we found that the viability and clonogenic ability of the cells treated with apigenin was less or more affected by transfection of the cells with a Axl-expressing plasmid or Axl targeting siRNA, compared to transfection with the empty vector or control siRNA, respectively. In addition, apigenin increased the expression of p21, a cyclin-dependent kinase inhibitor, but reduced the expression of X-linked inhibitor of apoptosis protein (XIAP). These cell cycle arrest and pro-apoptotic effects of apigenin were also attenuated or augmented by the up- or downregulation of Axl expression, respectively, which suggests that Axl is a novel target of apigenin through which it exerts its inhibitory effects on cell proliferation. Taken together, our data indicate that apigenin downregulates Axl expression, which subsequently results in the inhibition of NSCLC cell proliferation through the increase and decrease of p21 and XIAP expression, respectively.

  5. 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.

  6. Bruton’s Tyrosine Kinase Promotes Persistence of Mature Anti-Insulin B Cells

    Science.gov (United States)

    Bonami, Rachel H.; Sullivan, Allison M.; Case, James B.; Steinberg, Hannah E.; Hoek, Kristen L.; Khan, Wasif N.; Kendall, Peggy L.

    2014-01-01

    Autoreactive B lymphocytes are essential for the development of T cell–mediated type 1 diabetes (T1D). Cytoplasmic Bruton’s tyrosine kinase (BTK) is a key component of B cell signaling, and its deletion in T1D-prone NOD mice significantly reduces diabetes. However, the role of BTK in the survival and function of autoreactive B cells is not clear. To evaluate the contributions of BTK, we used mice in which B cells express an anti-insulin BCR (125Tg) and promote T1D, despite being anergic. Crossing Btk deficiency onto 125Tg mice reveals that, in contrast to immature B cells, mature anti-insulin B cells are exquisitely dependent upon BTK, because their numbers are reduced by 95%. BTK kinase domain inhibition reproduces this effect in mature anti-insulin B cells, with less impact at transitional stages. The increased dependence of anti-insulin B cells on BTK became particularly evident in an Igκ locus site–directed model, in which 50% of B cells edit their BCRs to noninsulin specificities; Btk deficiency preferentially depletes insulin binders from the follicular and marginal zone B cell subsets. The persistent few Btk-deficient anti-insulin B cells remain competent to internalize Ag and invade pancreatic islets. As such, loss of BTK does not significantly reduce diabetes incidence in 125Tg/NOD mice as it does in NOD mice with a normal B cell repertoire. Thus, BTK targeting may not impair autoreactive anti-insulin B cell function, yet it may provide protection in an endogenous repertoire by decreasing the relative availability of mature autoreactive B cells. PMID:24453243

  7. Tyrosine kinase Etk/BMX protects nasopharyngeal carcinoma cells from apoptosis induced by radiation.

    Science.gov (United States)

    Zhang, Zhenhua; Zhu, Weiliang; Zhang, Jian; Guo, Linlang

    2011-04-01

    Etk (Epithelial and endothelial tyrosine kinase), also known as Bmx (bone marrow X kinase) plays an important role in apoptosis of cancer cells. The purpose of this study was to investigate whether Etk/Bmx is involved in the apoptosis induced by irradiation in NPC cells and correlated with the apoptosis associated proteins such as p53, Bcl-2, Bcl-X(L) and Bak. To this end, we first developed a NPC subline (SUNE1-Etk) by transfection. The SUNE1-Etk that over-expresses Etk/BMX and its parental SUNE1 cell line were used to confirm whether Etk/BMX can protect NPC cells from apoptosis induced by radiation. The proliferation rates or the level of cell survival following irradiation were assessed by MTT and flow cytometry. Tumorigenecity study was done to substantiate the results in vitro. The results showed that the cell viability was significantly higher in SUNE1-Etk cells than that in parental SUNE1 cells in vitro, and tumors inoculated with SUNE1-Etk cells grew rapidly than those with SUNE1 after irradiation treatment. Our data also demonstrated that the up-expression of Etk/BMX increased G(2)/M arrest in response to irradiation. The protein level of p53 was greatly down-regulated whereas Bcl-2 was up-regulated, after irradiation treatment of SUNE1-Etk cells. Our results suggested that Etk/BMX may play a role in protection of NPC cells from apoptosis, and both p53 and Bcl-2 may be involved in radiation-induced apoptosis through Etk/Bmx pathway in NPC cells.

  8. Cyclic AMP-insensitive activation of c-Src and Syk protein-tyrosine kinases through platelet membrane glycoprotein VI.

    Science.gov (United States)

    Ichinohe, T; Takayama, H; Ezumi, Y; Yanagi, S; Yamamura, H; Okuma, M

    1995-11-24

    Platelet glycoprotein (GP) VI is a so-far uncharacterized 62-kDa membrane protein, whose deficiency results in selective impairment in collagen-induced platelet aggregation. Our group previously reported a human polyclonal antibody (anti-p62 IgG) that induces activation of normal, but not of GPVI-deficient, platelets in an Fc-independent manner. The F(ab')2 fragments of this antibody (F(ab')2-anti-p62) stimulated tyrosine phosphorylation of numerous proteins, which was not prevented even in the presence of cAMP-increasing agents such as prostacyclin. Pretreatment of platelets with the protein-tyrosine kinase (PTK) inhibitor tyrphostin A47 completely abolished F(ab')2-anti-p62-induced platelet aggregation in parallel with dose-dependent inhibition of protein-tyrosine phosphorylation, indicating an essential requirement of PTK activity for generating GPVI-mediated signaling. We found that two cytosolic PTKs, c-Src and Syk, became rapidly activated in response to F(ab')2-anti-p62 in a way insensitive to elevation of cAMP. In contrast, in the presence of prostacyclin, F(ab')2-anti-p62 did not stimulate tyrosine phosphorylation of the focal adhesion kinase. cAMP-insensitive activation of c-Src and Syk was also observed in collagen but not thrombin-stimulated platelets. Moreover, either F(ab')2-anti-p62 or collagen stimulated cAMP-insensitive tyrosine phosphorylation of phospholipase C-gamma 2. These results indicate that the receptor-mediated activation of several PTKs in platelets is regulated through a cAMP-sensitive or -insensitive mechanism depending on the nature of each stimulus, and also suggest that GPVI engagement is coupled to cAMP-insensitive activation of c-Src and Syk accompanied by tyrosine phosphorylation of numerous substrates including phospholipase C-gamma 2 in a manner similar to collagen stimulation.

  9. MHC-I-induced apoptosis in human B-lymphoma cells is dependent on protein tyrosine and serine/threonine kinases

    DEFF Research Database (Denmark)

    Pedersen, Anders Elm; Bregenholt, S; Johansen, B;

    1999-01-01

    B lymphoma cells, is dependent on protein tyrosine kinases and the phosphatidylinositol 3 (PI-3) kinase. Functional studies showed that MHC-I crosslinking induced almost complete inhibition of the spontaneous proliferation of the B lymphoma cells as early as 6 h post-crosslinking and apoptosis 24 h...... post-crosslinking. Preincubation with either protein tyrosine kinase or protein serine/threonine kinase inhibitors reduced the MHC-I-induced apoptosis to background levels, whereas inhibition of PI-3 kinase had no effect. These data demonstrate a pivotal role for protein tyrosine and serine....../threonine kinases in MHC-I-mediated apoptosis in human B-cells and suggest the presence of several MHC-I signaling pathways leading to diverse effects in these cells....

  10. Insulin receptor binding and tyrosine kinase activity in skeletal muscle from normal pregnant women and women with gestational diabetes

    DEFF Research Database (Denmark)

    Damm, P; Handberg, A; Kühl, C

    1993-01-01

    OBJECTIVE: To ascertain whether the decreased glucose tolerance and insulin resistance found in normal and gestational diabetic pregnancy might be associated with changes in insulin receptor function. METHODS: Eight nonpregnant healthy women (nonpregnant controls), eight healthy pregnant women...... (pregnant controls), and eight women with gestational diabetes were investigated. All were non-obese. Muscle biopsies were obtained from the vastus lateralis muscle, and insulin binding and tyrosine kinase activities in partially purified skeletal muscle insulin receptors were studied. The pregnant controls...... with gestational diabetes compared to nonpregnant controls (P pregnant women did not differ from the other two groups. Postpartum, no differences in insulin binding were found between the groups. Basal and maximal tyrosine kinase activities toward the exogenous substrate poly(Glu4Tyr1) were...

  11. Tyrosine kinase inhibitors improve parenchymal findings of liver cirrhosis in a patient exhibiting concomitant hepatocellular carcinoma and renal cell cancer

    Science.gov (United States)

    KUS, TULAY; AKTAS, GOKMEN; SEVINC, ALPER; OKTAY, CEMIL; KALENDER, MEHMET EMIN; CAMCI, CELALETDIN

    2016-01-01

    Hepatocellular carcinoma (HCC) and renal cell cancer (RCC) are malignancies, which are chemotherapy resistant and fatal at the advanced stages. Previously developed tyrosine kinase inhibitors are used in the treatment of advanced stage disease. In the present case study, a patient using sunitinib for stage IV RCC presented with HCC following 2 years of treatment. A patient who exhibited Child-Pugh class C cirrhosis initially, exhibited a marked improvement of hepatocellular parenchyma findings following treatment with sunitinib. Sunitinib is suggested to have preventive effects on the pathogenesis of liver fibrosis and cirrhosis in vitro, via an anti-vascular endothelial growth factor and anti-platelet-derived growth factor mechanism. However, no clinical supportive study has been performed until now. Improvement of liver functions may be explained in this manner. Therefore, investigations are required with different doses of sunitinib and other tyrosine kinase inhibitors in order to evaluate the efficacy on treatment of cirrhosis progression. PMID:26893877

  12. ANKRD54 preferentially selects Bruton's Tyrosine Kinase (BTK) from a Human Src-Homology 3 (SH3) domain library.

    Science.gov (United States)

    Gustafsson, Manuela O; Mohammad, Dara K; Ylösmäki, Erkko; Choi, Hyunseok; Shrestha, Subhash; Wang, Qing; Nore, Beston F; Saksela, Kalle; Smith, C I Edvard

    2017-01-01

    Bruton's Tyrosine Kinase (BTK) is a cytoplasmic protein tyrosine kinase with a fundamental role in B-lymphocyte development and activation. The nucleocytoplasmic shuttling of BTK is specifically modulated by the Ankyrin Repeat Domain 54 (ANKRD54) protein and the interaction is known to be exclusively SH3-dependent. To identify the spectrum of the ANKRD54 SH3-interactome, we applied phage-display screening of a library containing all the 296 human SH3 domains. The BTK-SH3 domain was the prime interactor. Quantitative western blotting analysis demonstrated the accuracy of the screening procedure. Revealing the spectrum and specificity of ANKRD54-interactome is a critical step toward functional analysis in cells and tissues.

  13. Pilose antler polypeptides promote chondrocyte proliferation via the tyrosine kinase signaling pathway

    Directory of Open Access Journals (Sweden)

    Lin Jian-Hua

    2011-11-01

    Full Text Available Abstract Background Pilose antler polypeptides (PAP have been reported to promote chondrocyte proliferation. However, the underlying mechanism remains unclear. The present study was to investigate the effects of PAP on the proliferation of chondrocytes and its underlying mechanism. Methods Chondrocytes isolated from the knee of Zealand white rabbits were cultured. The second generation chondrocytes were collected and identified using safranin-O staining. The chondrocytes were divided into the following 4 groups including serum-free, PAP, genistein (an inhibitor of tyrosine kinases, and PAP plus genistein group. Cell viability was analyzed using the MTT assay. The cell cycle distribution of the chondrocytes was analyzed by flow cytometry. The expression levels of cyclin A was detected using immunocytochemical staining. Results No significant difference was observed between serum-free and genistein group. Treatment of the cultures with PAP produced a significant dose-dependent increase in cell viability, the percentage proportion of chondrocytes in the S phase and Cyclin A expression as well. However, the promoting effect of PAP on chondrocyte proliferation were dose-dependently inhibited by genistein, whereas genistein alone had no effect on proliferation of isolated chondrocytes. Conclusions The data demonstrate that PAP promotes chondrocyte proliferation with the increased cell number, percentage proportion of chondrocytes in S phase and expression of protein cyclin A via the TK signaling pathway.

  14. Site-Specific N-Glycosylation of Endothelial Cell Receptor Tyrosine Kinase VEGFR-2.

    Science.gov (United States)

    Chandler, Kevin Brown; Leon, Deborah R; Meyer, Rosana D; Rahimi, Nader; Costello, Catherine E

    2017-02-03

    Vascular endothelial growth factor receptor-2 (VEGFR-2) is an important receptor tyrosine kinase (RTK) that plays critical roles in both physiologic and pathologic angiogenesis. The extracellular domain of VEGFR-2 is composed of seven immunoglobulin-like domains, each with multiple potential N-glycosylation sites (sequons). N-glycosylation plays a central role in RTK ligand binding, trafficking, and stability. However, despite its importance, the functional role of N-glycosylation of VEGFR-2 remains poorly understood. The objectives of the present study were to characterize N-glycosylation sites in VEGFR-2 via enzymatic release of the glycans and concomitant incorporation of (18)O into formerly N-glycosylated sites followed by tandem mass spectrometry (MS/MS) analysis to determine N-glycosylation site occupancy and the site-specific N-glycan heterogeneity of VEGFR-2 glycopeptides. The data demonstrated that all seven VEGFR-2 immunoglobulin-like domains have at least one occupied N-glycosylation site. MS/MS analyses of glycopeptides and deamidated, deglycosylated (PNGase F-treated) peptides from ectopically expressed VEGFR-2 in porcine aortic endothelial (PAE) cells identified N-glycans at the majority of the 17 potential N-glycosylation sites on VEGFR-2 in a site-specific manner. The data presented here provide direct evidence for site-specific, heterogeneous N-glycosylation and N-glycosylation site occupancy on VEGFR-2. The study has important implications for the therapeutic targeting of VEGFR-2, ligand binding, trafficking, and signaling.

  15. Dermatologic Toxicities from Monoclonal Antibodies and Tyrosine Kinase Inhibitors against EGFR: Pathophysiology and Management

    Directory of Open Access Journals (Sweden)

    Shaad E. Abdullah

    2012-01-01

    Full Text Available 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 EGFR inhibition is a papulopustular (also described as maculopapular or acneiform rash which occurs in about two thirds of treated patients. Interestingly, this rash has been commonly correlated with better clinical outcomes (objective tumor response and patient survival. The pathophysiology of dermatological toxicity from EGFR inhibitors is an important area of clinical research, and the proper management of the rash is essential to increase the therapeutic index from this class of drugs. In this paper, we review the dermatologic toxicities associated with EGFR inhibitors with an emphasis on its pathophysiology and clinical management.

  16. Extracellular domain determinants of LET-23 (EGF) receptor tyrosine kinase activity in Caenorhabditis elegans.

    Science.gov (United States)

    Moghal, Nadeem; Sternberg, Paul W

    2003-08-21

    Negative regulation of ErbB/EGFR signalling pathways is important for normal development and the prevention of cancer. In a genetic screen to uncover mechanisms that negatively regulate ErbB signalling in Caenorhabditis elegans, we isolated a second-site mutation (sy621) that promotes the activity of a gain-of-function allele (sa62gf) of the let-23 (EGF) receptor tyrosine kinase. We show that activation by the sa62 mutation (C359Y) likely results from a break in the conserved disulphide-bonded eighth module at the junction of CR1 and L2. The sy621 mutation causes a G270E change in the third disulphide-bonded module of CR1, and causes no phenotype on its own, but cooperates with the sa62 mutation to promote receptor activity. Although both sa62 single- and double-mutant receptors can function in the absence of ligand, they can be further activated by ligand. Our results support the current model for ligand-induced dimerization based on the recent crystal structures of HER3 and the EGFR, and provide more evidence for the generation of distinctly activated ErbB family members through mutation.

  17. Third generation tyrosine kinase inhibitors and their development in advanced renal cell carcinoma.

    Science.gov (United States)

    Bukowski, Ronald M

    2012-01-01

    Angiogenesis in general and the vascular endothelial growth factor (VEGF) signaling axis in particular is a validated target in renal cell carcinoma (RCC). Clear-cell carcinoma of the kidney is now recognized as a malignancy that is sensitive to inhibitors of the VEGF pathway. Treatment options for patients with metastatic renal cell carcinoma have evolved in dramatic fashion over the past 6 years, and a new paradigm has developed. The cytokines interferon-α and interleukin-2 were previously utilized for therapy, but since December 2005, six new agents have been approved in the United States for the treatment of advanced RCC. Two are tyrosine kinase inhibitors (TKI's) including sunitinib and recently pazopanib, and the multikinase inhibitor sorafenib. The current review examines the evolving data with the next generation of TKI's, axitinib and tivozanib being developed for the treatment of advanced RCC. These agents were synthesized to provide increased target specificity and enhanced target inhibition. The preclinical and clinical data are examined, an overview of the development of these TKI's is provided, and discussion plus speculation concerning their potential roles as RCC therapy is provided.

  18. Review : Third Generation Tyrosine Kinase Inhibitors and Their Development in Advanced Renal Cell Carcinoma

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    Ronald M Bukowski

    2012-02-01

    Full Text Available Angiogenesis in general and the VEGF signaling axis in particular is a validated target in renal cell carcinoma. Clear cell carcinoma of the kidney is now recognized as a malignancy that is sensitive to inhibitors of the vascular endothelial growth factor pathway. Treatment options for patients with metastatic renal cell carcinoma have evolved in dramatic fashion over the past six years, and a new paradigm has developed. The cytokines interferon-α and interleukin-2 were previously utilized for therapy, but since December 2005, six new agents have been approved in the United States for the treatment of advanced RCC. Three are tyrosine kinase inhibitors (TKI’s including sunitinib, sorafenib, and recently pazopanib. The current review examines the evolving data with the next generation of TKI’s, axitinib and tivozanib being developed for the treatment of advanced RCC. These agents were synthesized to provide increased target specificity and enhanced target inhibition. The preclinical and clinical data are examined, an overview of the development of these TKI’s is provided, and discussion plus speculation concerning their potential roles as RCC therapy is provided.

  19. Analysis of Tyrosine Kinase Inhibitor-Mediated Decline in Contractile Force in Rat Engineered Heart Tissue

    Science.gov (United States)

    Cuello, Friederike; Luther, Pradeep; Schulze, Thomas; Eder, Alexandra; Streichert, Thomas; Mannhardt, Ingra; Hirt, Marc N.; Schaaf, Sebastian; Stenzig, Justus; Force, Thomas

    2016-01-01

    Introduction Left ventricular dysfunction is a frequent and potentially severe side effect of many tyrosine kinase inhibitors (TKI). The mode of toxicity is not identified, but may include impairment of mitochondrial or sarcomeric function, autophagy or angiogenesis, either as an on-target or off-target mechanism. Methods and Results We studied concentration-response curves and time courses for nine TKIs in three-dimensional, force generating engineered heart tissue (EHT) from neonatal rat heart cells. We detected a concentration- and time-dependent decline in contractile force for gefitinib, lapatinib, sunitinib, imatinib, sorafenib, vandetanib and lestaurtinib and no decline in contractile force for erlotinib and dasatinib after 96 hours of incubation. The decline in contractile force was associated with an impairment of autophagy (LC3 Western blot) and appearance of autophagolysosomes (transmission electron microscopy). Conclusion This study demonstrates the feasibility to study TKI-mediated force effects in EHTs and identifies an association between a decline in contractility and inhibition of autophagic flux. PMID:26840448

  20. Predictive factor and antihypertensive usage of tyrosine kinase inhibitor-induced hypertension in kidney cancer patients

    Science.gov (United States)

    IZUMI, KOUJI; ITAI, SHINGO; TAKAHASHI, YOSHIKO; MAOLAKE, AERKEN; NAMIKI, MIKIO

    2014-01-01

    Hypertension (HT) is the common adverse event associated with vascular endothelial growth factor receptor-tyrosine kinase inhibitors (VEGFR-TKI). The present study was performed to identify the predictive factors of TKI-induced HT and to determine the classes of antihypertensive agents (AHTA) that demonstrate optimal efficacy against this type of HT. The charts of 50 cases of patients that had received VEGFR-TKI treatment were retrospectively examined. The association between patient background and TKI-induced HT, and the effect of administering AHTA were analyzed. High systolic blood pressure at baseline was identified to be a predictive factor for HT. In addition, there was no difference observed between calcium channel blockers (CCBs) and angiotensin receptor II blockers (ARBs) as first-line AHTA for the control of HT. The findings of the present study may aid with predicting the onset of TKI-induced HT, as well as for its management via the primary use of either CCBs or ARBs. PMID:24959266

  1. Spleen tyrosine kinase Syk is critical for sustained leukocyte adhesion during inflammation in vivo

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    Poeschl Johannes

    2007-11-01

    Full Text Available Abstract Background During inflammation, β2-integrins mediate leukocyte adhesion to the endothelium accompanied by the activation of the spleen tyrosine kinase Syk. Results We investigated leukocyte adhesion and rolling in cremaster muscle venules before and during stimulation with fMLP using mice with a Syk-/- hematopoietic system. In unstimulated venules, Syk-/- leukocytes adhered less efficiently than control leukocytes while rolling was similar between Syk-/- and control leukocytes. During fMLP-superfusion, control mice showed significantly increased adhesion accompanied by reduced rolling. For Syk-/- leukocytes, an increase in adhesion with a concomitant decrease in rolling was only observed during the first three minutes during fMLP stimulation, but not at later time points. We also investigated leukocyte spreading against the vessel wall during fMLP stimulation and found a significant impairment of spreading for Syk-/- leukocytes. Additional in vitro experiments revealed that the adhesion and spreading defect seen in Syk-/- chimeric mice was due to compromised β2-integrin-mediated outside-in signaling. Conclusion We provide substantial evidence for an important role of Syk in mediating β2-integrin dependent outside-in signaling leading to sustained leukocyte adhesion and spreading during the inflammatory response in vivo.

  2. The Dtk receptor tyrosine kinase, which binds protein S, is expressed during hematopoiesis.

    Science.gov (United States)

    Crosier, P S; Freeman, S A; Orlic, D; Bodine, D M; Crosier, K E

    1996-02-01

    Dtk (Tyro 3/Sky/Rse/Brt/Tif) belongs to a recently recognized subfamily of receptor tyrosine kinases that also includes Ufo (Axl/Ark) and Mer (Eyk). Ligands for Dtk and Ufo have been identified as protein S and the related molecule Gas6, respectively. This study examined expression of Dtk during ontogeny of the hematopoietic system and compared the pattern of expression with that of Ufo. Both receptors were abundantly expressed in differentiating embryonic stem cells, yolk sac blood islands, para-aortic splanchnopleural mesoderm, fractionated AA4+ fetal liver cells, and fetal thymus from day 14 until birth. Although Ufo was expressed at moderate levels in adult bone marrow, expression of Dtk in this tissue was barely detectable. In adult bone marrow subpopulations fractionated using counterflow centrifugal elutriation, immunomagnetic bead selection for lineage-depletion and FACS sorting for c-kit expression, very low levels of Dtk and/or Ufo were detected in some cell fractions. These results suggest that Dtk and Ufo are likely to be involved in the regulation of hematopoiesis, particularly during the embryonic stages of blood cell development.

  3. The Tyrosine Kinase Inhibitor Sunitinib Affects Ovulation but Not Ovarian Reserve in Mouse: A Preclinical Study

    Science.gov (United States)

    Bernard, Valérie; Bouilly, Justine; Kramer, Piet; Carré, Nadège; Schlumberger, Martin; Visser, Jenny A.; Young, Jacques; Binart, Nadine

    2016-01-01

    The aim of the study was to evaluate ovarian toxicity of tyrosine kinase inhibitor (TKI) sunitinib, since only scarce data are available on gonadal function after this treatment. Six-week-old female mice received orally, once daily, vehicle or sunitinib (50 mg/kg/d) during 5 weeks. Fertility parameters were analyzed from ovulation to litter assessment. Sunitinib exposure significantly reduced (i) corpora lutea number per ovary (1.1 ± 0.38 in sunitinib group versus 4 ± 0.79 in control group, p<0.01) and (ii) serum Anti Müllerian hormone (AMH) levels in sunitinib treated mice (12.01 ± 1.16) compared to control mice (14.33 ± 0.87 ng/ml, p< 0.05). However, primordial and growing follicles numbers per ovary were not different in both groups. After treatment withdrawal, female mice in both groups were able to obtain litters. These data could be helpful to counsel clinicians and patients, when fertility preservation methods are discussed, before TKI treatment in girls and young women. PMID:27035144

  4. Bypass mechanisms of resistance to tyrosine kinase inhibition in chronic myelogenous leukaemia.

    Science.gov (United States)

    Marfe, Gabriella; Di Stefano, Carla

    2014-06-01

    Chronic myeloid leukaemia (CML) is a disease induced by the BCR-ABL oncogene. Tyrosine kinase inhibitors (TKIs) were introduced in the late 1990s and have revolutionized the management of CML. The majority of such patients can now expect to live a normal life providing they continue to comply with TKI treatment. However, in a significant proportion of cases, TKI resistance develops over time, requiring a change of therapy. Over the past few years, multiple molecular mechanisms of resistance have been identified and some common themes have emerged. One is the development of resistance mutations in the drug target that prevent the drug from effectively inhibiting the respective TK domain. The second is activation of alternative molecules that maintain the signalling of key downstream pathways despite sustained inhibition of the original drug target. In this mini-review, we summarize the concepts underlying resistance, the specific examples known to date and the challenges of applying this knowledge to develop improved therapeutic strategies to prevent or overcome resistance.

  5. Induction of human pancreatic beta cell replication by inhibitors of dual specificity tyrosine regulated kinase

    Science.gov (United States)

    Wang, Peng; Alvarez-Perez, Juan-Carlos; Felsenfeld, Dan P.; Liu, Hongtao; Sivendran, Sharmila; Bender, Aaron; Kumar, Anil; Sanchez, Roberto; Scott, Donald K.; Garcia-Ocaña, Adolfo; Stewart, Andrew F.

    2015-01-01

    Types 1 and 2 diabetes affect some 380 million people worldwide. Both result ultimately from a deficiency of functional pancreatic insulin-producing beta cells. Beta cells proliferate in humans during a brief temporal window beginning around the time of birth, with peak beta cell labeling indices achieving approximately 2% in first year of life1-4. In embryonic life and after early childhood, beta cell replication rates are very low. While beta cell expansion seems an obvious therapeutic approach to beta cell deficiency, adult human beta cells have proven recalcitrant to such efforts1-8. Hence, there remains an urgent need for diabetes therapeutic agents that can induce regeneration and expansion of adult human beta cells in vivo or ex vivo. Here, we report the results of a high-throughput small molecule screen (HTS) revealing a novel class of human beta cell mitogenic compounds, analogues of the small molecule, harmine. We also define dual specificity tyrosine-regulated kinase-1a (DYRK1A) as the likely target of harmine, and the Nuclear Factors of activated T-cells (NFAT) family of transcription factors as likely mediators of human beta cell proliferation as well as beta cell differentiation. These observations suggest that harmine analogues (“harmalogs”) may have unique therapeutic promise for human diabetes therapy. Enhancing potency and beta cell specificity are important future challenges. PMID:25751815

  6. Mediation of transitional B cell maturation in the absence of functional Bruton’s tyrosine kinase

    Science.gov (United States)

    Tanwar, Shalini; Dhar, Atika; Varanasi, Vineeth; Mukherjee, Tapas; Boppana, Ramanamurthy; Basak, Soumen; Bal, Vineeta; George, Anna; Rath, Satyajit

    2017-01-01

    X-linked immune-deficient (Xid) mice, carrying a mutation in Bruton’s tyrosine kinase (Btk), have multiple B cell lineage differentiation defects. We now show that, while Xid mice showed only mild reduction in the frequency of the late transitional (T2) stage of peripheral B cells, the defect became severe when the Xid genotype was combined with either a CD40-null, a TCRbeta-null or an MHC class II (MHCII)-null genotype. Purified Xid T1 and T2 B cells survived poorly in vitro compared to wild-type (WT) cells. BAFF rescued WT but not Xid T1 and T2 B cells from death in culture, while CD40 ligation equivalently rescued both. Xid transitional B cells ex vivo showed low levels of the p100 protein substrate for non-canonical NF-kappaB signalling. In vitro, CD40 ligation induced equivalent activation of the canonical but not of the non-canonical NF-kappaB pathway in Xid and WT T1 and T2 B cells. CD40 ligation efficiently rescued p100-null T1 B cells from neglect-induced death in vitro. These data indicate that CD40-mediated signals, likely from CD4 T cells, can mediate peripheral transitional B cell maturation independent of Btk and the non-canonical NF-kappaB pathway, and thus contribute to the understanding of the complexities of peripheral B cell maturation. PMID:28378771

  7. Inhibition of interleukin-1 signaling enhances elimination of tyrosine kinase inhibitor-treated CML stem cells.

    Science.gov (United States)

    Zhang, Bin; Chu, Su; Agarwal, Puneet; Campbell, Victoria L; Hopcroft, Lisa; Jørgensen, Heather G; Lin, Allen; Gaal, Karl; Holyoake, Tessa L; Bhatia, Ravi

    2016-12-08

    Treatment of chronic myelogenous leukemia (CML) with BCR-ABL tyrosine kinase inhibitors (TKI) fails to eliminate leukemia stem cells (LSC). Patients remain at risk for relapse, and additional approaches to deplete CML LSC are needed to enhance the possibility of discontinuing TKI treatment. We have previously reported that expression of the pivotal proinflammatory cytokine interleukin-1 (IL-1) is increased in CML bone marrow. We show here that CML LSC demonstrated increased expression of the IL-1 receptors, IL-1 receptor accessory protein and IL-1 receptor type 1 (IL-1R1), and enhanced sensitivity to IL-1-induced NF-κB signaling compared with normal stem cells. Treatment with recombinant IL-1 receptor antagonist (IL-1RA) inhibited IL-1 signaling in CML LSC and inhibited growth of CML LSC. Importantly, the combination of IL-1RA with TKI resulted in significantly greater inhibition of CML LSC compared with TKI alone. Our studies also suggest that IL-1 signaling contributes to overexpression of inflammatory mediators in CML LSC, suggesting that blocking IL-1 signaling could modulate the inflammatory milieu. We conclude that IL-1 signaling contributes to maintenance of CML LSC following TKI treatment and that IL-1 blockade with IL-1RA enhances elimination of TKI-treated CML LSC. These results provide a strong rationale for further exploration of anti-IL-1 strategies to enhance LSC elimination in CML. © 2016 by The American Society of Hematology.

  8. The Tyrosine Kinase Inhibitor Sunitinib Affects Ovulation but Not Ovarian Reserve in Mouse: A Preclinical Study.

    Directory of Open Access Journals (Sweden)

    Valérie Bernard

    Full Text Available The aim of the study was to evaluate ovarian toxicity of tyrosine kinase inhibitor (TKI sunitinib, since only scarce data are available on gonadal function after this treatment. Six-week-old female mice received orally, once daily, vehicle or sunitinib (50 mg/kg/d during 5 weeks. Fertility parameters were analyzed from ovulation to litter assessment. Sunitinib exposure significantly reduced (i corpora lutea number per ovary (1.1 ± 0.38 in sunitinib group versus 4 ± 0.79 in control group, p<0.01 and (ii serum Anti Müllerian hormone (AMH levels in sunitinib treated mice (12.01 ± 1.16 compared to control mice (14.33 ± 0.87 ng/ml, p< 0.05. However, primordial and growing follicles numbers per ovary were not different in both groups. After treatment withdrawal, female mice in both groups were able to obtain litters. These data could be helpful to counsel clinicians and patients, when fertility preservation methods are discussed, before TKI treatment in girls and young women.

  9. FMS-LIKE TYROSINE KINASE (FLT3 GENE ITD MUTATION IN ACUTE MYELOID LEUKEMIA

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    Rajko Kusec

    2004-12-01

    Full Text Available Background. FLT3 is a class III receptor tyrosine kinase expressed in normal stem cells and blasts of myeloid leukemia. Internal tandem duplication (ITD of the FLT3 gene affecting the exons 14 and 15 leads to ligand-independent FLT3 dimerization and constitutive activation. This stimulates proliferation and induces inhibition of apoptosis which contributes to leukemogenesis. We have screened a panel of acute myeloid leukemia (AML patients for the occurrence of FLT3/ITD mutation and correlated this mutation to patients’ survival and basic hematological parameters.Methods. RT-PCR for ITD in exons 14 and 15 of FLT3 gene was done on bone marrow samples of 67 AML patients at diagnosis.Results. There was a 16.4% incidence of FLT3/ITD mutation in the cohort of examined patients. By cytognetic subgroups there were 2/6 t(15;17 and 1 of 4 t(8;21 positive patients. The rest had normal and 2 had complex karyotype. Majority were of FAB M2 or M4 phenotype. For a subset of patients taken into comparative survival analysis there was a clear disadvantage for FLT3/ITD patients. No difference was found for basic hematological parameters between two groups.Conclusions. As it is evident today that FLT3/ITD is the single most common genetic abnormality in AML that also presents unfavorable clinical prognostic marker, it should be included in molecular diagnostic testing of acute myeloid leukemia.

  10. 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.

  11. Tyrosine kinase domain mutations of EGFR gene in head and neck squamous cell carcinoma

    Science.gov (United States)

    Vatte, Chittibabu; Al Amri, Ali M; Cyrus, Cyril; Chathoth, Shahanas; Acharya, Sadananda; Hashim, Tariq Mohammad; Al Ali, Zhara; Alshreadah, Saleh Tawfeeq; Alsayyah, Ahmed; Al-Ali, Amein K

    2017-01-01

    Background Epidermal growth factor receptor (EGFR) is a commonly altered gene that is identified in various cancers, including head and neck squamous cell carcinoma (HNSCC). Therefore, EGFR is a promising molecular marker targeted by monoclonal antibodies and small molecule inhibitors targeting the tyrosine kinase (TK) domain. Objective The objective of this study was to investigate the spectrum of mutations in exons 18, 19, 20, and 21 of the EGFR gene in HNSCC patients. Materials and methods This retrospective study included 47 confirmed HNSCC cases. Mutations in the TK domain, exons 18, 19, 20, and 21 of the EGFR gene, were detected by Scorpion® chemistry and ARMS® technologies on Rotor-Gene Q real-time polymerase chain reaction. Results The tumors exhibited EGFR-TK domain mutations in 57% of cases. Four cases of T790M mutations were reported for the first time among HNSCC patients. Out of the total mutations, L861Q (exon 21), exon 20 insertions and deletions of exon 19 accounted for the majority of mutations (21%, 19%, and 17%, respectively). EGFR mutation status was correlated with the higher grade (P=0.026) and advanced stage (P=0.034) of HNSCC tumors. Conclusion Higher frequency of EGFR-TK domain mutations together with the presence of the T790M mutation suggests that identification of these mutations might streamline the therapy and provide a better prognosis in HNSCC cases. PMID:28352186

  12. Therapeutic Blockade of Immune Complex-Mediated Glomerulonephritis by Highly Selective Inhibition of Bruton's Tyrosine Kinase.

    Science.gov (United States)

    Chalmers, Samantha A; Doerner, Jessica; Bosanac, Todd; Khalil, Sara; Smith, Dustin; Harcken, Christian; Dimock, Janice; Der, Evan; Herlitz, Leal; Webb, Deborah; Seccareccia, Elise; Feng, Di; Fine, Jay S; Ramanujam, Meera; Klein, Elliott; Putterman, Chaim

    2016-05-19

    Lupus nephritis (LN) is a potentially dangerous end organ pathology that affects upwards of 60% of lupus patients. Bruton's tyrosine kinase (BTK) is important for B cell development, Fc receptor signaling, and macrophage polarization. In this study, we investigated the effects of a novel, highly selective and potent BTK inhibitor, BI-BTK-1, in an inducible model of LN in which mice receive nephrotoxic serum (NTS) containing anti-glomerular antibodies. Mice were treated once daily with vehicle alone or BI-BTK-1, either prophylactically or therapeutically. When compared with control treated mice, NTS-challenged mice treated prophylactically with BI-BTK-1 exhibited significantly attenuated kidney disease, which was dose dependent. BI-BTK-1 treatment resulted in decreased infiltrating IBA-1+ cells, as well as C3 deposition within the kidney. RT-PCR on whole kidney RNA and serum profiling indicated that BTK inhibition significantly decreased levels of LN-relevant inflammatory cytokines and chemokines. Renal RNA expression profiling by RNA-seq revealed that BI-BTK-1 dramatically modulated pathways related to inflammation and glomerular injury. Importantly, when administered therapeutically, BI-BTK-1 reversed established proteinuria and improved renal histopathology. Our results highlight the important role for BTK in the pathogenesis of immune complex-mediated nephritis, and BTK inhibition as a promising therapeutic target for LN.

  13. Effective virtual screening strategy focusing on the identification of novel Bruton's tyrosine kinase inhibitors.

    Science.gov (United States)

    Xiao, Jianhu; Zhang, Shengping; Luo, Minghao; Zou, Yi; Zhang, Yihua; Lai, Yisheng

    2015-07-01

    Dysregulation of the B-cell receptor (BCR) signaling pathway plays a vital role in the pathogenesis and development of B-cell malignancies. Bruton's tyrosine kinase (BTK), a key component in the BCR signaling, has been validated as a valuable target for the treatment of B-cell malignancies. In an attempt to find novel and potent BTK inhibitors, both ligand- and structure-based pharmacophore models were generated using Discovery Studio 2.5 and Ligandscout 3.11 with the aim of screening the ChemBridge database. The resulting hits were then subjected to sequential docking experiments using two independent docking programs, CDOCKER and Glide. Molecules displaying high glide scores and H-bond interactions with the key residue Met477 in both of the docking programs were retained. Drug-like criteria including Lipinski's rule of five and ADMET properties filters were employed for further refinement of the retrieved hits. By clustering, eight promising compounds with novel chemical scaffolds were finally selected and the top two ranking compounds were evaluated by molecular dynamics simulation. We believe that these compounds are of great potential in BTK inhibition and will be used for further investigation. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Bruton's tyrosine kinase inhibitors in B-cell lymphoma: current experience and future perspectives.

    Science.gov (United States)

    Seiler, T; Dreyling, M

    2017-08-01

    The Bruton tyrosine kinase (BTK) is a central hub in the B cell receptor (BCR) pathway and strongly influences B cell maturation, differentiation and proliferation. Not surprisingly, BTK plays an essential role in the pathogenesis of various B cell lymphomas. Inhibitors of BTK have broadened our therapeutic options in several B cell lymphomas and already are an integral element in the treatment of Mantle Cell Lymphoma (MCL), chronic lymphocytic leukemia (CLL) and Waldenström's marcoglobulinemia. Several second generation BTK inhibitors are in clinical development and might further improve tolerability and efficacy of therapy in advanced stage CLL and MCL. Areas covered: This review illustrates the mechanism of action of BTK inhibitors and provides a comprehensive summary of key clinical trials in the development of BTK inhibitors. Characteristics of second generation BTK-inhibitors are described. Expert opinion: With accumulation of clinical experience after drug approval, longer patient follow-up and larger numbers of treated patients, future development will focus on the identification of intelligent treatment combinations. Individual selection of patients with distinct biologically properties might guide treatment decisions. While BTK inhibitors are moving to earlier treatment lines, the incorporation of these drugs into a comprehensive therapeutic strategy is still difficult to date.

  15. Bruton's tyrosine kinase regulates TLR9 but not TLR7 signaling in human plasmacytoid dendritic cells.

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    Wang, Jingming; Lau, Kai-Yeung; Jung, Jimmy; Ravindran, Palanikumar; Barrat, Franck J

    2014-04-01

    Plasmacytoid dendritic cells (PDCs) represent a key cell type for both innate and adaptive immunity. PDCs express both TLR7 and TLR9 and the recognition of nucleic acids by these two receptors triggers the production of a large amount of type-I IFN and the induction of PDC maturation into APCs. This unique feature of PDCs is at the basis of clinical development of both TLR7 and TLR9 agonists for infectious diseases, allergy, cancer, and asthma. However, TLR7 and TLR9 recognition of self-nucleic acids is linked to many autoimmune diseases including lupus, and a better understanding of the signaling pathways of these two receptors in PDCs is thus important. We have identified Bruton's tyrosine kinase (Btk) as an important player for TLR9 but not TLR7 signaling in human PDCs. Blocking Btk using a specific inhibitor leads to the reduction of all TLR9-induced responses in PDCs, including cytokine production and expression of costimulatory molecules, while this has no impact on the TLR7 response. This identifies Btk as a key molecule in TLR9 signaling in PDCs and is the first demonstration that the TLR7 and TLR9 pathways can be dissociated in human PDCs. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. The tyrosine kinase Btk regulates the macrophage response to Listeria monocytogenes infection.

    Directory of Open Access Journals (Sweden)

    Afitap Derya Köprülü

    Full Text Available In this study we investigated the role of Bruton's tyrosine kinase (Btk in the immune response to the Gram-positive intracellular bacterium Listeria monocytogenes (Lm. In response to Lm infection, Btk was activated in bone marrow-derived macrophages (BMMs and Btk (-/- BMMs showed enhanced TNF-α, IL-6 and IL-12p40 secretion, while type I interferons were produced at levels similar to wild-type (wt BMMs. Although Btk-deficient BMMs displayed reduced phagocytosis of E. coli fragments, there was no difference between wt and Btk (-/- BMMs in the uptake of Lm upon infection. Moreover, there was no difference in the response to heat-killed Lm between wt and Btk (-/- BMMs, suggesting a role for Btk in signaling pathways that are induced by intracellular Lm. Finally, Btk (-/- mice displayed enhanced resistance and an increased mean survival time upon Lm infection in comparison to wt mice. This correlated with elevated IFN-γ and IL-12p70 serum levels in Btk (-/- mice at day 1 after infection. Taken together, our data suggest an important regulatory role for Btk in macrophages during Lm infection.

  17. QSAR analysis of nicotinamidic compounds and design of potential Bruton's tyrosine kinase (Btk) inhibitors.

    Science.gov (United States)

    Santos-Garcia, Letícia; Assis, Letícia C; Silva, Daniela R; Ramalho, Teodorico C; da Cunha, Elaine F F

    2016-07-01

    Bruton's tyrosine kinase (Btk) is an important enzyme in B-lymphocyte development and differentiation. Furthermore, Btk expression is considered essential for the proliferation and survival of these cells. Btk inhibition has become an attractive strategy for treating autoimmune diseases, B-cell leukemia, and lymphomas. With the objective of proposing new candidates for Btk inhibitors, we applied receptor-dependent four-dimensional quantitative structure-activity relationship (QSAR) methodology to a series of 96 nicotinamide analogs useful as Btk modulators. The QSAR models were developed using 71 compounds, the training set, and externally validated using 25 compounds, the test set. The conformations obtained by molecular dynamics simulation were overlapped in a virtual three-dimensional cubic box comprised of 2 and 5 Å cells, according to the six trial alignments. The models were generated by combining genetic function approximation and partial least squares regression technique. The analyses suggest that Model 1a yields the best results. The best equation shows [Formula: see text], r(2) = .743, RMSEC = .831, RMSECV = .879. Given the importance of the Tyr551, this residue could become a strategic target for the design of novel Btk inhibitors with improved potency. In addition, the good potency predicted for the proposed M2 compound indicates this compound as a potential Btk inhibitor candidate.

  18. Bruton's tyrosine kinase inhibitors in B-cell non-Hodgkin's lymphomas.

    Science.gov (United States)

    Alinari, L; Quinion, C; Blum, K A

    2015-05-01

    The B-cell receptor pathway (BCR) is aberrantly activated in select B-cell malignancies. This knowledge has allowed for the development of inhibitors of different crucial steps of this pathway. Bruton's tyrosine kinase (BTK) is a key component of BCR signaling and functions as an important regulator of multiple cell functions including differentiation, proliferation, and survival in various B-cell malignancies. Ibrutinib is a potent, selective BTK inhibitor that has shown significant activity in specific subtypes of B-cell non-Hodgkin's lymphomas (NHLs). Given the high response rates, tolerability, and acceptable toxicities, ibrutinib was recently approved by the US Food and Drug Administration (FDA) for the treatment of patients with relapsed mantle cell lymphoma and chronic lymphocytic leukemia. It is also currently being evaluated in combination with chemotherapy and as frontline therapy in B-cell NHL. This review summarizes the preclinical and clinical development of ibrutinib in the treatment of B-cell NHL. © 2015 American Society for Clinical Pharmacology and Therapeutics.

  19. Development of the Bruton's tyrosine kinase inhibitor ibrutinib for B cell malignancies.

    Science.gov (United States)

    Gayko, Urte; Fung, Mann; Clow, Fong; Sun, Steven; Faust, Elizabeth; Price, Samiyeh; James, Danelle; Doyle, Margaret; Bari, Samina; Zhuang, Sen Hong

    2015-11-01

    Ibrutinib is a first-in-class oral covalent inhibitor of Bruton's tyrosine kinase that has demonstrated clinical benefit for many patients with B cell malignancies. Positive results in initial trials led the U.S. Food and Drug Administration to grant ibrutinib three breakthrough therapy designations for mantle cell lymphoma (MCL), del17p chronic lymphocytic leukemia (CLL), and Waldenström's macroglobulinemia (WM). Ibrutinib was approved for these three cancers within 14 months of the original U.S. approval. Additionally, ibrutinib is approved for patient subsets with MCL and/or CLL in >45 other countries. Via a unique mechanism of action, ibrutinib inhibits B cell signaling pathways that regulate the survival, proliferation, adhesion, and homing of cancerous cells. This marks a paradigm shift from the conventional cytotoxic chemotherapy approach to treating B cell malignancies. Ibrutinib continues to be evaluated across a range of B cell malignancies, either as single-agent therapy or in combination with other therapies, and continues to transform the lives of these patients. © 2015 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals Inc. on behalf of The New York Academy of Sciences.

  20. Bruton's tyrosine kinase is essential for NLRP3 inflammasome activation and contributes to ischaemic brain injury.

    Science.gov (United States)

    Ito, Minako; Shichita, Takashi; Okada, Masahiro; Komine, Ritsuko; Noguchi, Yoshiko; Yoshimura, Akihiko; Morita, Rimpei

    2015-06-10

    Inflammasome activation has been implicated in various inflammatory diseases including post-ischaemic inflammation after stroke. Inflammasomes mediate activation of caspase-1, which subsequently induces secretion of pro-inflammatory cytokines such as IL-1β and IL-18, as well as a form of cell death called pyroptosis. In this study, we report that Bruton's tyrosine kinase (BTK) is an essential component of the NLRP3 inflammasome, in which BTK physically interacts with ASC and NLRP3. Inhibition of BTK by pharmacological or genetic means severely impairs activation of the NLRP3 inflammasome. The FDA-approved BTK inhibitor ibrutinib (PCI-32765) efficiently suppresses infarct volume growth and neurological damage in a brain ischaemia/reperfusion model in mice. Ibrutinib inhibits maturation of IL-1β by suppressing caspase-1 activation in infiltrating macrophages and neutrophils in the infarcted area of ischaemic brain. Our study indicates that BTK is essential for NLRP3 inflammasome activation and could be a potent therapeutic target in ischaemic stroke.

  1. Bruton's tyrosine kinase inhibitors: lessons learned from bench-to-bedside (first) studies.

    Science.gov (United States)

    Ysebaert, Loic; Michallet, Anne-Sophie

    2014-09-01

    Targeted inhibitors of B-cell receptor signaling have emerged as the most promising therapeutic options against non-Hodgkin's lymphoma. The inhibitor agents that target Bruton's tyrosine kinase (BTK) have elicited particularly high enthusiasm given the unprecedented positive responses observed in Phase I trials. The sheer amount of clinical data published since last year now requires reinterpretation in light of recently published findings on BTK. Clinical trial data pertaining to various B-cell dyscrasia forms must be interpreted with great caution. The differing response rates reported with various BTK inhibitors for a range of lymphoma subtypes most likely mirror BTK's disease-specific pivotal role in the regulation of cell survival, migration, and proliferation pathways. It must also be stressed that activating or inhibitory somatic mutations affecting other critical components of targeted signaling cascades dramatically impact BTK inhibitor efficacy, and scientific evidence is mounting that warrants patient screening to identify those who, based on B-cell receptor activation modes, most likely benefit from BTK inhibitors. Recent developments in BTK-based therapeutic strategies have undoubtedly changed the way we approach lymphoma therapy. As of yet, there is no cure for indolent lymphoma, and the future of BTK inhibitor therapy will undoubtedly include rational combinations to exploit synthetic lethality in distinct lymphoma subsets.

  2. Mediation of transitional B cell maturation in the absence of functional Bruton's tyrosine kinase.

    Science.gov (United States)

    Tanwar, Shalini; Dhar, Atika; Varanasi, Vineeth; Mukherjee, Tapas; Boppana, Ramanamurthy; Basak, Soumen; Bal, Vineeta; George, Anna; Rath, Satyajit

    2017-04-05

    X-linked immune-deficient (Xid) mice, carrying a mutation in Bruton's tyrosine kinase (Btk), have multiple B cell lineage differentiation defects. We now show that, while Xid mice showed only mild reduction in the frequency of the late transitional (T2) stage of peripheral B cells, the defect became severe when the Xid genotype was combined with either a CD40-null, a TCRbeta-null or an MHC class II (MHCII)-null genotype. Purified Xid T1 and T2 B cells survived poorly in vitro compared to wild-type (WT) cells. BAFF rescued WT but not Xid T1 and T2 B cells from death in culture, while CD40 ligation equivalently rescued both. Xid transitional B cells ex vivo showed low levels of the p100 protein substrate for non-canonical NF-kappaB signalling. In vitro, CD40 ligation induced equivalent activation of the canonical but not of the non-canonical NF-kappaB pathway in Xid and WT T1 and T2 B cells. CD40 ligation efficiently rescued p100-null T1 B cells from neglect-induced death in vitro. These data indicate that CD40-mediated signals, likely from CD4 T cells, can mediate peripheral transitional B cell maturation independent of Btk and the non-canonical NF-kappaB pathway, and thus contribute to the understanding of the complexities of peripheral B cell maturation.

  3. Emergence of Bruton's tyrosine kinase-negative Hodgkin lymphoma during ibrutinib treatment of chronic lymphocytic leukaemia.

    Science.gov (United States)

    Glavey, Siobhan; Quinn, John; McCloy, Mary; Sargent, Jeremy; McCartney, Yvonne; Catherwood, Mark; Marafioti, Teresa; Leader, Mary; Murphy, Philip; Thornton, Patrick

    2017-10-01

    Chronic lymphocytic leukaemia (CLL) is a chronic B-cell lympho-proliferative disorder in which lymphomatous transformations occur in 5%-15% of patients. Histologically these cases resemble diffuse large B-cell lymphoma, or Richter's transformation, in over 80% of cases. Rare cases of transformation to Hodgkin lymphoma (HL) have been reported in the literature with an estimated prevalence of 0.4%. We report a case of a 67-year-old female with CLL treated with the novel Bruton's tyrosine kinase (Btk) inhibitor, ibrutinib, who subsequently presented with intractable fevers. Bone marrow trephine, and lymph node biopsy revealed classical HL with negative immuno-histochemistry for Btk in HL cells, on a backdrop of CLL. The patient commenced treatment with Adriamycin, Vinblastine and Dacarbazine (AVD), which resulted in an excellent response. Hodgkin transformation of CLL is rare with a single retrospective study of 4121 CLL patients reporting only 18 cases. Btk expression in HL cells is recently recognised in classical HL; however, the majority of HLs are Btk negative. Given that Btk inhibitors have recently been shown to induce genomic instability in B cells, in the context of their widespread use, such emerging cases are increasingly relevant. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Induction of antagonistic soluble decoy receptor tyrosine kinases by intronic polyA activation.

    Science.gov (United States)

    Vorlová, Sandra; Rocco, Gina; Lefave, Clare V; Jodelka, Francine M; Hess, Ken; Hastings, Michelle L; Henke, Erik; Cartegni, Luca

    2011-09-16

    Alternative intronic polyadenylation (IPA) can generate truncated protein isoforms with significantly altered functions. Here, we describe 31 dominant-negative, secreted variant isoforms of receptor tyrosine kinases (RTKs) that are produced by activation of intronic poly(A) sites. We show that blocking U1-snRNP can activate IPA, indicating a larger role for U1-snRNP in RNA surveillance. Moreover, we report the development of an antisense-based method to effectively and specifically activate expression of individual soluble decoy RTKs (sdRTKs) to alter signaling, with potential therapeutic implications. In particular, a quantitative switch from signal transducing full-length vascular endothelial growth factor receptor-2 (VEGFR2/KDR) to a dominant-negative sKDR results in a strong antiangiogenic effect both on directly targeted cells and on naive cells exposed to conditioned media, suggesting a role for this approach in interfering with angiogenic paracrine and autocrine loops. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. Dermatologic Toxicities from Monoclonal Antibodies and Tyrosine Kinase Inhibitors against EGFR: Pathophysiology and Management

    Science.gov (United States)

    Abdullah, Shaad E.; Haigentz, Missak; Piperdi, Bilal

    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 EGFR inhibition is a papulopustular (also described as maculopapular or acneiform) rash which occurs in about two thirds of treated patients. Interestingly, this rash has been commonly correlated with better clinical outcomes (objective tumor response and patient survival). The pathophysiology of dermatological toxicity from EGFR inhibitors is an important area of clinical research, and the proper management of the rash is essential to increase the therapeutic index from this class of drugs. In this paper, we review the dermatologic toxicities associated with EGFR inhibitors with an emphasis on its pathophysiology and clinical management. PMID:22997576

  6. Anti-Angiogenic Therapy: Strategies to Develop Potent VEGFR-2 Tyrosine Kinase Inhibitors and Future Prospect.

    Science.gov (United States)

    Shi, Leilei; Zhou, Jianfeng; Wu, Jifeng; Shen, Yuemao; Li, Xun

    2016-01-01

    Tumor angiogenesis has always been a major gap for effective cancer therapy. Interruption of aberrant angiogenesis by specific inhibitors targeting receptor tyrosine kinases (RTKs) has been of great interests to medicinal chemists. Among the factors that are involved in tumor angiogenesis, vascular endothelial growth factor receptor-2 (VEGFR-2) is validated as the most closely related factor which can drive angiogenesis through binding with its natural ligand VEGF. The well-validated VEGF-driven VEGFR-2 signaling pathway can stimulate many endothelial responses, including increasing vessel permeability and enhancing endothelial cell proliferation, migration and differentiation. Consequently, circumventing angiogenesis by VEGFR-2 inhibitors represents a promising strategy for counteracting various VEGFR-2-mediated disorders as well as drug resistance. Over the past decades, a considerable number of novel small molecular VEGFR-2 inhibitors have been exploited with diverse chemical scaffolds. Especially, recent frequently launched inhibitors have declared their research values and therapeutic potentials in oncology. Still, the antiangiogenesis based treatment remains an ongoing challenge. In this review, a comprehensive retrospective of newly emerged VEGFR-2 inhibitors have been summarized, with the emphasis on the structure-activity relationship (SAR) investigation, and also binding patterns of representative inhibitors with biotargets. On the basis of all of this information, varied strategies for developing potent VEGFR-2 inhibitors and the future prospect of the clinical application of antiangiogenic inhibitors are discussed hereby.

  7. Phosphorylation impact on Spleen Tyrosine kinase conformation by Surface Enhanced Raman Spectroscopy

    Science.gov (United States)

    Cottat, Maximilien; Yasukuni, Ryohei; Homma, Yo; Lidgi-Guigui, Nathalie; Varin-Blank, Nadine; Lamy de La Chapelle, Marc; Le Roy, Christine

    2017-01-01

    Spleen Tyrosine Kinase (Syk) plays a crucial role in immune cell signalling and its altered expression or activation are involved in several cancers. Syk activity relies on its phosphorylation status and its multiple phosphorylation sites predict several Syk conformations. In this report, we characterized Syk structural changes according to its phosphorylation/activation status by Surface Enhanced Raman Spectroscopy (SERS). Unphosphorylated/inactive and phosphorylated/active Syk forms were produced into two expression systems with different phosphorylation capability. Syk forms were then analysed by SERS that was carried out in liquid condition on a lithographically designed gold nanocylinders array. Our study demonstrated that SERS signatures of the two Syk forms were drastically distinct, indicating structural modifications related to their phosphorylation status. By comparison with the atomic structure of the unphosphorylated Syk, the SERS peak assignments of the phosphorylated Syk nearest gold nanostructures revealed a differential interaction with the gold surface. We finally described a model for Syk conformational variations according to its phosphorylation status. In conclusion, SERS is an efficient technical approach for studying in vitro protein conformational changes and might be a powerful tool to determine protein functions in tumour cells.

  8. Overexpression of Fyn tyrosine kinase causes abnormal development of primary sensory neurons in Xenopus laevis embryos.

    Science.gov (United States)

    Saito, R; Fujita, N; Nagata, S

    2001-06-01

    The expression and function of the Src family protein tyrosine kinase Fyn in Xenopus laevis embryos have been examined. In situ hybridization analysis demonstrated nervous system-specific expression of Fyn mRNA in tail-bud embryos. However, a class of primary sensory neurons; that is, Rohon-Beard (RB) neurons, which is positive for immunoglobulin superfamily cell adhesion molecules (CAM), neural cell adhesion molecule (N-CAM) and contactin, is devoid of Fyn expression. Injection of Fyn mRNA into one of the blastomeres at the 2-cell stage led to overexpression of Fyn in the injected half of the tail-bud embryos. Immunolabeling of the embryos with anti-HNK-1 antibody revealed that the peripheral axons of RB neurons were partially misguided and bound to each other to form abnormal subcutaneous fascicles. Similar abnormality was induced by injection of the Fyn overexpression vector. The incidence of abnormality appeared dose-dependent, being 68-92% of the injected embryos at 50-400 pg of mRNA. Co-injection of the contactin antisense vector depleted contactin mRNA accumulation without affecting Fyn overexpression and reduced the incidence of the abnormal RB-cell phenotype. However, the N-CAM antisense was ineffective in reducing this abnormality. These results suggest that Fyn can modify signals regulating axonal guidance or fasciculation in the developing X. laevis nervous system and that contactin may affect this action of Fyn.

  9. Pilot study of extracorporeal removal of soluble fms-like tyrosine kinase 1 in preeclampsia.

    Science.gov (United States)

    Thadhani, Ravi; Kisner, Tuelay; Hagmann, Henning; Bossung, Verena; Noack, Stefanie; Schaarschmidt, Wiebke; Jank, Alexander; Kribs, Angela; Cornely, Oliver A; Kreyssig, Claudia; Hemphill, Linda; Rigby, Alan C; Khedkar, Santosh; Lindner, Tom H; Mallmann, Peter; Stepan, Holger; Karumanchi, S Ananth; Benzing, Thomas

    2011-08-23

    Targeted therapies to stabilize the clinical manifestations and prolong pregnancy in preeclampsia do not exist. Soluble fms-like tyrosine kinase 1 (sFlt-1), an alternatively spliced variant of the vascular endothelial growth factor receptor 1, induces a preeclampsia-like phenotype in experimental models and circulates at elevated levels in human preeclampsia. Removing sFlt-1 may benefit women with very preterm (<32 weeks) preeclampsia. We first show that negatively charged dextran sulfate cellulose columns adsorb sFlt-1 in vitro. In 5 women with very preterm preeclampsia and elevated circulating sFlt-1 levels, we next demonstrate that a single dextran sulfate cellulose apheresis treatment reduces circulating sFlt-1 levels in a dose-dependent fashion. Finally, we performed multiple apheresis treatments in 3 additional women with very preterm (gestational age at admission 28, 30, and 27+4 weeks) preeclampsia and elevated circulating sFlt-1 levels. Dextran sulfate apheresis lowered circulating sFlt-1, reduced proteinuria, and stabilized blood pressure without apparent adverse events to mother and fetus. Pregnancy lasted for 15 and 19 days in women treated twice and 23 days in a woman treated 4 times. In each, there was evidence of fetal growth. This pilot study supports the hypothesis that extracorporeal apheresis can lower circulating sFlt-1 in very preterm preeclampsia. Further studies are warranted to determine whether this intervention safely and effectively prolongs pregnancy and improves maternal and fetal outcomes in this setting.

  10. Lenalidomide in chronic lymphocytic leukemia: the present and future in the era of tyrosine kinase inhibitors.

    Science.gov (United States)

    Maffei, Rossana; Colaci, Elisabetta; Fiorcari, Stefania; Martinelli, Silvia; Potenza, Leonardo; Luppi, Mario; Marasca, Roberto

    2016-01-01

    Lenalidomide is an immunomodulatory agent (IMiD) clinically active in chronic lymphocytic leukemia (CLL), both in heavily pre-treated patients and upfront. Lenalidomide has a unique mechanism of action in CLL. Its efficacy relies on a multifactorial mode-of-action (MOA), comprising a plethora of immunomodulatory actions, the disruption of mutualistic interactions inside CLL microenvironment and direct effects against leukemic cells. In the last few years, a number of new and highly effective drugs appeared in the scenario of CLL therapeutic options, i.e. tyrosine kinase inhibitors (TKIs), showing a good safety profile and impressive clinical response, also in high-risk patients. In this review, we describe the data from clinical studies about lenalidomide efficacy in CLL and we critically dissect the different mechanisms of action of this drug. We point the attention on open issues, including drug dosage and administration schedule, prediction of clinical response to lenalidomide, and combination therapeutic strategies. This overview would be useful to envision a possible role of lenalidomide in the treatment flow-chart of CLL, exploiting its peculiar MOA and also exploring the possible synergetic effect with new drugs.

  11. Rociletinib, a third generation EGFR tyrosine kinase inhibitor: current data and future directions.

    Science.gov (United States)

    Chuang, Jody C; Salahudeen, Ameen A; Wakelee, Heather A

    2016-01-01

    Major advances have been made since the discovery of driver mutations and their targeted therapies, especially in the treatment of patients with epidermal growth factor receptor (EGFR) mutations. Despite their initial efficacy in the majority of the patients with such driver mutations, all targeted therapies are limited by the eventual development of resistance mechanisms. EGFR T790M mutation is a common resistance mechanism after treatment with first or second generation EGFR tyrosine kinase inhibitors (TKI). Rociletinib is one of the third generation EGFR TKIs with activity against T790M and activating EGFR mutations while sparing the wild-type EGFR. In this review, we discuss the current understanding and available data on rociletinib, including the side effects associated with the medication. We will also review the BEAMing plasma test to detect T790M mutation without the need for repeat biopsy. Lastly, we review the potential resistance mechanisms after progression on rociletinib, and future directions. It is important to note that there are other 3(rd) generation EGFR TKIs with activity against T790M already approved by the US FDA (osimertinib) and many others in development. Future research will focus on figuring out which patients can benefit the most from a particular medication with minimal side effects, and further resistance mechanisms after rociletinib.

  12. UV-Vis spectroscopy and solvatochromism of the tyrosine kinase inhibitor AG-1478.

    Science.gov (United States)

    Khattab, Muhammad; Wang, Feng; Clayton, Andrew H A

    2016-07-05

    The effect of twenty-one solvents on the UV-Vis spectrum of the tyrosine kinase inhibitor AG-1478 was investigated. The absorption spectrum in the range 300-360nm consisted of two partially overlapping bands at approximately 340nm and 330nm. The higher energy absorption band was more sensitive to solvent and exhibited a peak position that varied from 327nm to 336nm, while the lower energy absorption band demonstrated a change in peak position from 340nm to 346nm in non-chlorinated solvents. The fluorescence spectrum of AG-1478 was particularly sensitive to solvent. The wavelength of peak intensity varied from 409nm to 495nm with the corresponding Stokes shift in the range of 64nm to 155nm (4536cm(-1) to 9210cm(-1)). We used a number of methods to assess the relationship between spectroscopic properties and solvent properties. The detailed analysis revealed that for aprotic solvents, the peak position of the emission spectrum in wavenumber scale correlated with the polarity (dielectric constant or ET(30)) of the solvent. In protic solvents, a better correlation was observed between the hydrogen bonding power of the solvent and the position of the emission spectrum. Moreover, the fluorescence quantum yields were larger in aprotic solvents as compared to protic solvents. This analysis underscores the importance of polarity and hydrogen-bonding environment on the spectroscopic properties of AG-1478. These studies will assume relevance in understanding the interaction of AG-1478 in vitro and in vivo.

  13. Regulation of Discrete Functional Responses by Syk and Src Family Tyrosine Kinases in Human Neutrophils

    Directory of Open Access Journals (Sweden)

    Thornin Ear

    2017-01-01

    Full Text Available Neutrophils play a critical role in innate immunity and also influence adaptive immune responses. This occurs in good part through their production of inflammatory and immunomodulatory cytokines, in conjunction with their prolonged survival at inflamed foci. While a picture of the signaling machinery underlying these neutrophil responses is now emerging, much remains to be uncovered. In this study, we report that neutrophils constitutively express various Src family isoforms (STKs, as well as Syk, and that inhibition of these protein tyrosine kinases selectively hinders inflammatory cytokine generation by acting posttranscriptionally. Accordingly, STK or Syk inhibition decreases the phosphorylation of signaling intermediates (e.g., eIF-4E, S6K, and MNK1 involved in translational control. By contrast, delayed apoptosis appears to be independent of either STKs or Syk. Our data therefore significantly extend our understanding of which neutrophil responses are governed by STKs and Syk and pinpoint some signaling intermediates that are likely involved. In view of the foremost role of neutrophils in several chronic inflammatory conditions, our findings identify potential molecular targets that could be exploited for future therapeutic intervention.

  14. The tyrosine kinase inhibitor dasatinib induces a marked adipogenic differentiation of human multipotent mesenchymal stromal cells.

    Directory of Open Access Journals (Sweden)

    Adriana Borriello

    Full Text Available BACKGROUND: The introduction of specific BCR-ABL inhibitors in chronic myelogenous leukemia therapy has entirely mutated the prognosis of this hematologic cancer from being a fatal disorder to becoming a chronic disease. Due to the probable long lasting treatment with tyrosine-kinase inhibitors (TKIs, the knowledge of their effects on normal cells is of pivotal importance. DESIGN AND METHODS: We investigated the effects of dasatinib treatment on human bone marrow-derived mesenchymal stromal cells (MSCs. RESULTS: Our findings demonstrate, for the first time, that dasatinib induces MSCs adipocytic differentiation. Particularly, when the TKI is added to the medium inducing osteogenic differentiation, a high MSCs percentage acquires adipocytic morphology and overexpresses adipocytic specific genes, including PPARγ, CEBPα, LPL and SREBP1c. Dasatinib also inhibits the activity of alkaline phosphatase, an osteogenic marker, and remarkably reduces matrix mineralization. The increase of PPARγ is also confirmed at protein level. The component of osteogenic medium required for dasatinib-induced adipogenesis is dexamethasone. Intriguingly, the increase of adipocytic markers is also observed in MSCs treated with dasatinib alone. The TKI effect is phenotype-specific, since fibroblasts do not undergo adipocytic differentiation or PPARγ increase. CONCLUSIONS: Our data demonstrate that dasatinib treatment affects bone marrow MSCs commitment and suggest that TKIs therapy might modify normal phenotypes with potential significant negative consequences.

  15. Spleen tyrosine kinase contributes to acute renal allograft rejection in the rat.

    Science.gov (United States)

    Ramessur Chandran, Sharmila; Tesch, Greg H; Han, Yingjie; Woodman, Naomi; Mulley, William R; Kanellis, John; Blease, Kate; Ma, Frank Y; Nikolic-Paterson, David J

    2015-02-01

    Kidney allografts induce strong T-cell and antibody responses which mediate acute rejection. Spleen tyrosine kinase (Syk) is expressed by most leucocytes, except mature T cells, and is involved in intracellular signalling following activation of the Fcγ-receptor, B-cell receptor and some integrins. A role for Syk signalling has been established in antibody-dependent native kidney disease, but little is known of Syk in acute renal allograft rejection. Sprague-Dawley rats underwent bilateral nephrectomy and received an orthotopic Wistar renal allograft. Recipient rats were treated with a Syk inhibitor (CC0482417, 30 mg/kg/bid), or vehicle, from 1 h before surgery until being killed 5 days later. Vehicle-treated recipients developed severe allograft failure with marked histologic damage in association with dense leucocyte infiltration (T cells, macrophages, neutrophils and NK cells) and deposition of IgM, IgG and C3. Immunostaining identified Syk expression by many infiltrating leucocytes. CC0482417 treatment significantly improved allograft function and reduced histologic damage, although allograft injury was still clearly evident. CC0482417 failed to prevent T-cell infiltration and activation within the allograft. However, CC0482417 significantly attenuated acute tubular necrosis, infiltration of macrophages and neutrophils and thrombosis of peritubular capillaries. In conclusion, this study identifies a role for Syk in acute renal allograft rejection. Syk inhibition may be a useful addition to T-cell-based immunotherapy in renal transplantation.

  16. [DIETARY INTAKE AND NUTRITIONAL STATUS IN ONCOLOGY PATIENTS WHO START TREATMENT WITH TYROSINE KINASE INHIBITORS].

    Science.gov (United States)

    Higuera-Pulgar, Isabel; Ribed, Almudena; Carrascal-Fabian, M Luisa; Bretón-Lesmes, Irene; Romero-Jiménez, Rosa M; Cuerda-Compes, Cristina; Velasco-Gimeno, Cristina; Camblor-Álvarez, Miguel; García-Peris, Pilar

    2015-09-01

    in recent years, researching about new oral antineoplastics has progressed while its impact on dietary intake and nutritional status (NS) hasn't developed enough yet. dietary intake and NS assessment in patients who start treatment with tyrosine kinase inhibitors (TKI) and evaluate its impact on them. an observational, prospective-six-months study, in which were included patients starting treatment with TKI. The intake was evaluated by a 24 h dietary record and a food frequency questionnaire. The NS was evaluated by anthropometric measurements and the patient-generated Global Subjective Assessment (PG-GSA); the results were compared with the Spanish references (SENC-semFYC, 2007 and O. Moreiras, 2013). Friedman test, χ2, Wilcoxon, Kruskal-Wallis and Mann-Whitney were used in the statistical analysis. Significance p Dietary habits did not change during treatment. dietary intake did not reach nutritional requirements at baseline. The TKI don't seem to affect the patient's intake and nutritional status. The research about these parameters before starting treatment could prevent future complications and it would guide the dietary advice. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  17. [Receptor tyrosine kinase KIT may regulate expression of genes involved in spontaneous regression of neuroblastoma].

    Science.gov (United States)

    Lebedev, T D; Spirin, P V; Suntsova, M V; Ivanova, A V; Buzdin, A A; Prokofjeva, M M; Rubtsov, P M; Prassolov, V S

    2015-01-01

    Hallmark of neuroblastoma is an ability of this malignant tumor to undergo spontaneous regression or differentiation into benign tumor during any stage of the disease, but it is little known about mechanisms of these phenomena. We studied effect of receptor tyrosine kinase receptor KIT on expression of genes, which may be involved in tumor spontaneous regression. Downregulation of KIT expression by RNA interference in SH-SY5Y cells causes suppression of neurotrophin receptor NGFR expression that may promote the loss of sensibility of cells to nerve growth factors, also it causes upregulation of TrkA receptor expression which can stimulate cell differentiation or apoptosis in NGF dependent manner. Furthermore there is an upregulation of genes which stimulate malignant cell detection by immune system, such as genes of major histocompatibility complex HLA class I HLA-B and HLA-C, and interferon-γ receptors IFNGR1 and IFNGR2 genes. Thus KIT can mediate neuroblastoma cell sensibility to neurotrophins and immune system components--two factors directly contributing to spontaneous regression of neuroblastoma.

  18. A platinum-based hybrid drug design approach to circumvent acquired resistance to molecular targeted tyrosine kinase inhibitors

    Science.gov (United States)

    Wei, Yuming; Poon, Daniel C.; Fei, Rong; Lam, Amy S. M.; Au-Yeung, Steve C. F.; To, Kenneth K. W.

    2016-05-01

    Three molecular targeted tyrosine kinase inhibitors (TKI) were conjugated to classical platinum-based drugs with an aim to circumvent TKI resistance, predominately mediated by the emergence of secondary mutations on oncogenic kinases. The hybrids were found to maintain specificity towards the same oncogenic kinases as the original TKI. Importantly, they are remarkably less affected by TKI resistance, presumably due to their unique structure and the observed dual mechanism of anticancer activity (kinase inhibition and DNA damage). The study is also the first to report the application of a hybrid drug approach to switch TKIs from being efflux transporter substrates into non-substrates. TKIs cannot penetrate into the brain for treating metastases because of efflux transporters at the blood brain barrier. The hybrids were found to escape drug efflux and they accumulate more than the original TKI in the brain in BALB/c mice. Further development of the hybrid compounds is warranted.

  19. A platinum-based hybrid drug design approach to circumvent acquired resistance to molecular targeted tyrosine kinase inhibitors.

    Science.gov (United States)

    Wei, Yuming; Poon, Daniel C; Fei, Rong; Lam, Amy S M; Au-Yeung, Steve C F; To, Kenneth K W

    2016-05-06

    Three molecular targeted tyrosine kinase inhibitors (TKI) were conjugated to classical platinum-based drugs with an aim to circumvent TKI resistance, predominately mediated by the emergence of secondary mutations on oncogenic kinases. The hybrids were found to maintain specificity towards the same oncogenic kinases as the original TKI. Importantly, they are remarkably less affected by TKI resistance, presumably due to their unique structure and the observed dual mechanism of anticancer activity (kinase inhibition and DNA damage). The study is also the first to report the application of a hybrid drug approach to switch TKIs from being efflux transporter substrates into non-substrates. TKIs cannot penetrate into the brain for treating metastases because of efflux transporters at the blood brain barrier. The hybrids were found to escape drug efflux and they accumulate more than the original TKI in the brain in BALB/c mice. Further development of the hybrid compounds is warranted.

  20. Structural and dynamic insights into the free energy barrier for activation loop rearrangement in FGFR1 tyrosine kinase

    OpenAIRE

    Klein, Tobias; Vajpai, Navratna; Phillips, Jonathan J; Davies, Gareth,; Holdgate, Geoffrey A.; Phillips, Chris; Tucker, Julie A.; Norman, Richard A; Scott, Andrew D; Higazi, Daniel R.; Lowe, David; Thompson, Gary S.; Breeze, Alexander L.

    2015-01-01

    This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/ncomms8877 Protein tyrosine kinases differ widely in their propensity to undergo rearrangements of the N-terminal Asp–Phe–Gly (DFG) motif of the activation loop, with some, including FGFR1 kinase, appearing refractory to this so-called ‘DFG flip’. Recent inhibitor-bound structures have unexpectedly revealed FGFR1 for the first time in a ‘DFG-out’ state. Here we use conformationally...

  1. Discovery of Potent and Selective Tricyclic Inhibitors of Bruton’s Tyrosine Kinase with Improved Druglike Properties

    Science.gov (United States)

    2017-01-01

    In our continued effort to discover and develop best-in-class Bruton’s tyrosine kinase (Btk) inhibitors for the treatment of B-cell lymphomas, rheumatoid arthritis, and systemic lupus erythematosus, we devised a series of novel tricyclic compounds that improved upon the druglike properties of our previous chemical matter. Compounds exemplified by G-744 are highly potent, selective for Btk, metabolically stable, well tolerated, and efficacious in an animal model of arthritis. PMID:28626519

  2. [Efficacy of levocarnitine for tyrosine kinase inhibitor-induced painful muscle cramps in patients with chronic myelogenous leukemia].

    Science.gov (United States)

    Yamada, Michiko; Kuroda, Hiroyuki; Shimoyama, Saori; Ito, Ryo; Sugama, Yusuke; Sato, Ken; Yamauchi, Natsumi; Horiguchi, Hiroto; Nakamura, Hajime; Hamaguchi, Kota; Abe, Tomoyuki; Fujii, Shigeyuki; Maeda, Masahiro; Kato, Junji

    2016-04-01

    Muscle cramps are side effects commonly associated with tyrosine kinase inhibitor (TKI) treatment. Patients suffering from muscle cramps are treated with various medications such as calcium, magnesium and vitamin supplements, but these therapies are often ineffective. We report two patients with chronic myelogenous leukemia who developed muscle cramps caused by TKI. These patients were treated successfully with levocarnitine. Both of our cases revealed the beneficial effects of levocarnitine treatment on TKI-induced muscle cramps.

  3. A high-content EMT screen identifies multiple receptor tyrosine kinase inhibitors with activity on TGFβ receptor

    Science.gov (United States)

    Ackerknecht, Sabine; Lehembre, François; Fink, Tobias; Stritt, Manuel; Wirth, Matthias; Pavan, Simona; Bill, Ruben; Regenass, Urs; Christofori, Gerhard; Meyer-Schaller, Nathalie

    2016-01-01

    An epithelial to mesenchymal transition (EMT) enables epithelial tumor cells to break out of the primary tumor mass and to metastasize. Understanding the molecular mechanisms driving EMT in more detail will provide important tools to interfere with the metastatic process. To identify pharmacological modulators and druggable targets of EMT, we have established a novel multi-parameter, high-content, microscopy-based assay and screened chemical compounds with activities against known targets. Out of 3423 compounds, we have identified 19 drugs that block transforming growth factor beta (TGFβ)-induced EMT in normal murine mammary gland epithelial cells (NMuMG). The active compounds include inhibitors against TGFβ receptors (TGFBR), Rho-associated protein kinases (ROCK), myosin II, SRC kinase and uridine analogues. Among the EMT-repressing compounds, we identified a group of inhibitors targeting multiple receptor tyrosine kinases, and biochemical profiling of these multi-kinase inhibitors reveals TGFBR as a thus far unknown target of their inhibitory spectrum. These findings demonstrate the feasibility of a multi-parameter, high-content microscopy screen to identify modulators and druggable targets of EMT. Moreover, the newly discovered “off-target” effects of several receptor tyrosine kinase inhibitors have important consequences for in vitro and in vivo studies and might beneficially contribute to the therapeutic effects observed in vivo. PMID:27036020

  4. A high-content EMT screen identifies multiple receptor tyrosine kinase inhibitors with activity on TGFβ receptor.

    Science.gov (United States)

    Lotz-Jenne, Carina; Lüthi, Urs; Ackerknecht, Sabine; Lehembre, François; Fink, Tobias; Stritt, Manuel; Wirth, Matthias; Pavan, Simona; Bill, Ruben; Regenass, Urs; Christofori, Gerhard; Meyer-Schaller, Nathalie

    2016-05-03

    An epithelial to mesenchymal transition (EMT) enables epithelial tumor cells to break out of the primary tumor mass and to metastasize. Understanding the molecular mechanisms driving EMT in more detail will provide important tools to interfere with the metastatic process. To identify pharmacological modulators and druggable targets of EMT, we have established a novel multi-parameter, high-content, microscopy-based assay and screened chemical compounds with activities against known targets. Out of 3423 compounds, we have identified 19 drugs that block transforming growth factor beta (TGFβ)-induced EMT in normal murine mammary gland epithelial cells (NMuMG). The active compounds include inhibitors against TGFβ receptors (TGFBR), Rho-associated protein kinases (ROCK), myosin II, SRC kinase and uridine analogues. Among the EMT-repressing compounds, we identified a group of inhibitors targeting multiple receptor tyrosine kinases, and biochemical profiling of these multi-kinase inhibitors reveals TGFBR as a thus far unknown target of their inhibitory spectrum. These findings demonstrate the feasibility of a multi-parameter, high-content microscopy screen to identify modulators and druggable targets of EMT. Moreover, the newly discovered "off-target" effects of several receptor tyrosine kinase inhibitors have important consequences for in vitro and in vivo studies and might beneficially contribute to the therapeutic effects observed in vivo.

  5. Reduced intensity conditioning is superior to nonmyeloablative conditioning for older chronic myelogenous leukemia patients undergoing hematopoietic cell transplant during the tyrosine kinase inhibitor era

    DEFF Research Database (Denmark)

    Warlick, Erica; Ahn, Kwang Woo; Pedersen, Tanya L;

    2012-01-01

    Tyrosine kinase inhibitors (TKIs) and reduced intensity conditioning (RIC)/nonmyeloablative (NMA) conditioning hematopoietic cell transplants (HCTs) have changed the therapeutic strategy for chronic myelogenous leukemia (CML) patients. We analyzed post-HCT outcomes of 306 CML patients reported to...

  6. Different roles for non-receptor tyrosine kinases in arachidonate release induced by zymosan and Staphylococcus aureus in macrophages

    Directory of Open Access Journals (Sweden)

    Sundler Roger

    2006-05-01

    Full Text Available Abstract Background Yeast and bacteria elicit arachidonate release in macrophages, leading to the formation of leukotrienes and prostaglandins, important mediators of inflammation. Receptors recognising various microbes have been identified, but the signalling pathways are not entirely understood. Cytosolic phospholipase A2 is a major down-stream target and this enzyme is regulated by both phosphorylation and an increase in intracellular Ca2+. Potential signal components are MAP kinases, phosphatidylinositol 3-kinase and phospholipase Cγ2. The latter can undergo tyrosine phosphorylation, and Src family kinases might carry out this phosphorylation. Btk, a Tec family kinase, could also be important. Our aim was to further elucidate the role of Src family kinases and Btk. Methods Arachidonate release from murine peritoneal macrophages was measured by prior radiolabeling. Furthermore, immunoprecipitation and Western blotting were used to monitor changes in activity/phosphorylation of intermediate signal components. To determine the role of Src family kinases two different inhibitors with broad specificity (PP2 and the Src kinase inhibitor 1, SKI-1 were used as well as the Btk inhibitor LFM-A13. Results Arachidonate release initiated by either Staphylococcus aureus or yeast-derived zymosan beads was shown to depend on members of the Src kinase family as well as Btk. Src kinases were found to act upstream of Btk, phosphatidylinositol 3-kinase, phospholipase Cγ2 and the MAP kinases ERK and p38, thereby affecting all branches of the signalling investigated. In contrast, Btk was not involved in the activation of the MAP-kinases. Since the cytosolic phospholipase A2 in macrophages is regulated by both phosphorylation (via ERK and p38 and an increase in intracellular Ca2+, we propose that members of the Src kinase family are involved in both types of regulation, while the role of Btk may be restricted to the latter type. Conclusion Arachidonate release

  7. Molecular variation and evolution of the tyrosine kinase domains of insulin receptor IRa and IRb genes in Cyprinidae.

    Science.gov (United States)

    Kong, XiangHui; Wang, XuZhen; He, ShunPing

    2011-07-01

    The insulin receptor (IR) gene plays an important role in regulating cell growth, differentiation and development. In the present study, DNA sequences of insulin receptor genes, IRa and IRb, were amplified and sequenced from 37 representative species of the Cyprinidae and from five outgroup species from non-cyprinid Cypriniformes. Based on coding sequences (CDS) of tyrosine kinase regions of IRa and IRb, molecular evolution and phylogenetic relationships were analyzed to better understand the characteristics of IR gene divergence in the family Cyprinidae. IRa and IRb were clustered into one lineage in the gene tree of the IR gene family, reconstructed using the unweighted pair group method with arithmetic mean (UPGMA). IRa and IRb have evolved into distinct genes after IR gene duplication in Cyprinidae. For each gene, molecular evolution analyses showed that there was no significant difference among different groups in the reconstructed maximum parsimony (MP) tree of Cyprinidae; IRa and IRb have been subjected to similar evolutionary pressure among different lineages. Although the amino acid sequences of IRa and IRb tyrosine kinase regions were highly conserved, our analyses showed that there were clear sequence variations between the tyrosine kinase regions of IRa and IRb proteins. This indicates that IRa and IRb proteins might play different roles in the insulin signaling pathway.

  8. DDR2 plays a role in fibroblast migration independent of adhesion ligand and collagen activated DDR2 tyrosine kinase.

    Science.gov (United States)

    Herrera-Herrera, Mireya Liliana; Quezada-Calvillo, Roberto

    2012-12-07

    Discoidin domain receptor-2 (DDR2) is a cell surface tyrosine kinase receptor that can be activated by soluble collagen and has been implicated in diverse physiological functions including organism growth and wound repair. In the current studies, we used fibronectin and collagen-coated 2D surfaces and collagen matrices in combination with siRNA technology to investigate the role of DDR2 in a range of fibroblast motile activities. Silencing DDR2 with siRNA inhibited cell spreading and migration, and similar inhibition occurred regardless whether cells were interacting with fibronectin or collagen surfaces. Under the assay conditions used, DDR2 tyrosine kinase activation was not observed unless soluble collagen was added to the incubation medium. Finally silencing DDR2 also inhibited human fibroblast migration in 3D collagen matrices but had no effect on 3D collagen matrix remodeling and contraction. Taken together, our findings suggest that DDR2 is required for normal fibroblast spreading and migration independent of adhesion ligand and collagen activation of DDR2 tyrosine kinase.

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

    Directory of Open Access Journals (Sweden)

    Abbaspour Babaei M

    2016-08-01

    Full Text Available Maryam Abbaspour Babaei,1 Behnam Kamalidehghan,2,3 Mohammad Saleem,4–6 Hasniza Zaman Huri,1,7 Fatemeh Ahmadipour1 1Department of Pharmacy, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia; 2Department of Medical Genetics, National Institute of Genetic Engineering and Biotechnology (NIGEB, Shahrak-e Pajoohesh, 3Medical Genetics Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; 4Department of Urology, 5Department of Laboratory Medicine and Pathology, Masonic Cancer Center, University of Minnesota, 6Section of Molecular Therapeutics & Cancer Health Disparity, The Hormel Institute, Austin, MN, USA; 7Clinical Investigation Centre, University Malaya Medical Centre, Lembah Pantai, Kuala Lumpur, Malaysia Abstract: 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

  10. MD-2 interacts with Lyn kinase and is tyrosine phosphorylated following LPS-induced activation of the Toll-like receptor 4 signaling pathway

    Science.gov (United States)

    Gray, Pearl; Dagvadorj, Jargalsaikhan; Michelsen, Kathrin S.; Brikos, Constantinos; Rentsendorj, Altan; Town, Terrence; Crother, Timothy R.; Arditi, Moshe

    2011-01-01

    Stimulation with LPS induces tyrosine phosphorylation of numerous proteins involved in the TLR signaling pathway. In this study, we demonstrate that MD-2 is also tyrosine phosphorylated following LPS stimulation. LPS-induced tyrosine phosphorylation of MD-2 is specific, it is blocked by the tyrosine kinase inhibitor, Herbimycin A, and by an inhibitor of endocytosis, Cytochalsin-D, suggesting that MD-2 phosphorylation occurs during trafficking of MD2 and not on cell surface. Furthermore, we identify two possible phospho-accepting tyrosine residues at positions 22 and 131. Mutant proteins in which these tyrosines were changed to phenylalanine have reduced phosphorylation and significantly diminished ability to activate NF-κB in response to LPS. In addition, MD2 co-precipitates and colocalizes with Lyn kinase, most likely in ER. A Lyn-binding peptide inhibitor abolished MD2 tyrosine phosphorylation, suggesting that Lyn is a likely candidate to be the kinase required for MD-2 tyrosine phophorylation. Our study demonstrates that tyrosine phosphorylation of MD-2 is important for signaling following exposure to LPS and underscores the importance of this event in mediating an efficient and prompt immune response. PMID:21918188

  11. Myeloid differentiation factor-2 interacts with Lyn kinase and is tyrosine phosphorylated following lipopolysaccharide-induced activation of the TLR4 signaling pathway.

    Science.gov (United States)

    Gray, Pearl; Dagvadorj, Jargalsaikhan; Michelsen, Kathrin S; Brikos, Constantinos; Rentsendorj, Altan; Town, Terrence; Crother, Timothy R; Arditi, Moshe

    2011-10-15

    Stimulation with LPS induces tyrosine phosphorylation of numerous proteins involved in the TLR signaling pathway. In this study, we demonstrated that myeloid differentiation factor-2 (MD-2) is also tyrosine phosphorylated following LPS stimulation. LPS-induced tyrosine phosphorylation of MD-2 is specific; it is blocked by the tyrosine kinase inhibitor, herbimycin A, as well as by an inhibitor of endocytosis, cytochalasin D, suggesting that MD-2 phosphorylation occurs during trafficking of MD-2 and not on the cell surface. Furthermore, we identified two possible phospho-accepting tyrosine residues at positions 22 and 131. Mutant proteins in which these tyrosines were changed to phenylalanine had reduced phosphorylation and significantly diminished ability to activate NF-κB in response to LPS. In addition, MD-2 coprecipitated and colocalized with Lyn kinase, most likely in the endoplasmic reticulum. A Lyn-binding peptide inhibitor abolished MD-2 tyrosine phosphorylation, suggesting that Lyn is a likely candidate to be the kinase required for MD-2 tyrosine phosphorylation. Our study demonstrated that tyrosine phosphorylation of MD-2 is important for signaling following exposure to LPS and underscores the importance of this event in mediating an efficient and prompt immune response.

  12. Carcinoma of an unknown primary: are EGF receptor, Her-2/neu, and c-Kit tyrosine kinases potential targets for therapy?

    OpenAIRE

    Massard, C; Voigt, J-J; Laplanche, A; Culine, S; Lortholary, A; Bugat, R; Theodore, C.; Priou, F; Kaminsky, M-C; Lesimple, T; Pivot, X; B. Coudert; Douillard, J-Y; Merrouche, Y; Fizazi, K

    2007-01-01

    Carcinomas of an unknown primary site (CUP) are heterogeneous tumours with a median survival of only 8 months. Tyrosine kinase inhibitors are promising new drugs. The aim of this study was to determine the expression of EGF-receptor, Her-2/neu, and c-Kit tyrosine kinases in CUP. Paraffin-embedded specimens were obtained from 54 patients with a CUP who were included in the GEFCAPI 01 randomised phase II trial. Immunohistochemistry was performed using the Dako autostainer with antibodies direct...

  13. The expression of COX-2 in VEGF-treated endothelial cells is mediated through protein tyrosine kinase

    Directory of Open Access Journals (Sweden)

    Pravit Akarasereenont

    2002-01-01

    Full Text Available Cyclooxygenase (COX, existing as the COX-1 and COX-2 isoforms, converts arachidonic acid to prostaglandin H2, which is then further metabolized to various prostaglandins. Vascular endothelial growth factor (VEGF has been shown to play important roles in inflammation and is upregulated by the prostaglandin E series through COX-2 in several cell types. Here, we have investigated the effects of VEGF on the COX isoform expressed in human umbilical vein endothelial cells (HUVEC. The signalling mechanism of the COX isoform expressed in endothelial cells activated with VEGF will be also investigated using the tyrosine kinase inhibitor, genistein, and protein kinase C inhibitor, staurosporine. The activity of COX2 was assessed by measuring the production of 6-keto-prostaglandin F1α in the presence of exogenous arachidonic acids (10 μM, 10 min by enzyme immunoassay. The expression of COX isoform protein was detected by immunoblot using specific antibodies. Untreated HUVEC contained no COX-2 protein. In HUVEC treated with VEGF (0.01-50 ng/ml, COX-2 protein, but not COX-1, and COX activity were increased in a dose-dependent manner. Interestingly, the increased COX-2 protein and activity in response to VEGF (10 ng/ml was inhibited by the tyrosine kinase inhibitor, genistein (0.05-5 μg/ml, but not by the protein kinase C inhibitor, staurosporine (0.1-10 ng/ml. Thus, the induction of COX-2 by VEGF in endothelial cells was mediated through protein tyrosine kinase, and the uses of specific COX-2 inhibitors in these conditions, in which VEGF was involved, might have a role.

  14. Interaction of the growth hormone receptor cytoplasmic domain with the JAK2 tyrosine kinase.

    Science.gov (United States)

    Frank, S J; Gilliland, G; Kraft, A S; Arnold, C S

    1994-11-01

    An early step in GH action involves tyrosine phosphorylation of various cellular proteins. Recently, it has been shown in murine preadipocytes that GH promotes the association of its receptor (the GHR) with and the activation of the JAK2 tyrosine kinase. In this study, we confirmed the human (h) GH-induced association of JAK2 with hGHR in IM-9 cells by coimmunoprecipitation experiments using anti-hGHR serum. We further examined the interaction of JAK2 with the GHR cytoplasmic domain by two lines of investigation. For in vitro studies, we assayed by immunoblotting the ability of cell-derived JAK2 to interact with glutathione S-transferase fusion proteins containing elements of the hGHR cytoplasmic domain. A fusion protein containing the entire hGHR cytoplasmic domain (residues 271-620) specifically associated with JAK2 independent of prior stimulation of cells with hGH. This interaction was not dependent on tyrosine phosphorylation of either partner. Mutational analysis of the hGHR cytoplasmic domain component of the fusions indicated that a membrane-proximal 20-residue region that includes the proline-rich box 1 was necessary for the interaction. This region appeared to cooperate with another region(s), largely in the N-terminal one third of the cytoplasmic domain, to promote full interaction with JAK2. For in vivo reconstitution experiments, wild-type (WT) and mutant rabbit GHRs (rGHRs) along with murine JAK2 were expressed by transient transfection in COS-7 cells. rGHR mutations were confined to the cytoplasmic domain and included C-terminal truncations as well as internal deletions of residues 297-406 and 278-292 (the latter contains box 1). All mutant rGHRs were expressed at the cell surface and bound hGH to a degree similar to the WT rGHR. Receptors were tested for their ability to mediate the hGH-induced immunoprecipitability of JAK2 with phosphotyrosine (APT) antibodies. A rGHR truncated to residue 275 [rGHR-(1-275)], which contains only five cytoplasmic

  15. The Bmx tyrosine kinase is activated by IL-3 and G-CSF in a PI-3K dependent manner.

    Science.gov (United States)

    Ekman, N; Arighi, E; Rajantie, I; Saharinen, P; Ristimäki, A; Silvennoinen, O; Alitalo, K

    2000-08-24

    Cytoplasmic protein tyrosine kinases play crucial roles in signaling via a variety of cell surface receptors. The Bmx tyrosine kinase, a member of the Tec family, is expressed in hematopoietic cells of the granulocytic and monocytic lineages. Here we show that Bmx is catalytically activated by interleukin-3 (IL-3) and granulocyte-colony stimulating factor (G-CSF) receptors. Activation of Bmx required phosphatidylinositol 3-kinase (PI-3K) as demonstrated by the ability of PI-3K inhibitors to block the activation signal. A green fluorescent protein (GFP) tagged Bmx was translocated to cellular membranes upon co-expression of a constitutively active form of PI-3K, further indicating a role for PI-3K in signaling upstream of Bmx. The expression of wild type Bmx in 32D myeloid progenitor cells resulted in apoptosis in the presence of G-CSF, while cells expressing a kinase dead mutant of Bmx differentiated into mature granulocytes. However, Bmx did not modulate IL-3-dependent proliferation of the cells. These results demonstrate distinct effects of Bmx in cytokine induced proliferation and differentiation of myeloid cells, and suggest that the stage specific expression of Bmx is critical for the differentiation of myeloid cells. Oncogene (2000) 19, 4151 - 4158

  16. The torpedo (DER) receptor tyrosine kinase is required at multiple times during Drosophila embryogenesis.

    Science.gov (United States)

    Clifford, R; Schüpbach, T

    1992-07-01

    The torpedo (DER) gene of Drosophila, which encodes a receptor tyrosine kinase of the EGF receptor subfamily, is essential for oogenesis, embryogenesis and imaginal disc development. To gain insight into the nature of the signals transduced by the torpedo product, we have characterized the gene's loss-of-function phenotype in the embryo. Through the induction of germline clones, we provide a genetic demonstration that maternal torpedo product does not contribute to zygotic development. Thus, the embryonic lethal phenotypes examined accurately reflect the consequences of eliminating all gene activity from the zygote. Temperature-shift experiments with the conditional allele topIF26 show that torpedo is required at two distinct times during embryonic development: the gene is first needed for germband retraction and for the production of anterior, posterior and ventral cuticle, then later for the secretion of ventral denticles. Since denticle formation can be severely disrupted in topIF26 animals without affecting cuticle production, the early and late requirements for torpedo appear to be functionally unrelated. torpedo, therefore, is required at multiple times in the development of the ventral epidermis, and may transduce qualitatively different signals. Since the early requirement for torpedo correlates with the first visible defect in embryonic development, increased cell death in the amnioserosa, cephalic ectoderm and ventral epidermis, the abnormalities in cuticle production and germband shortening seen in the mutant may be secondary consequences of a primary defect in cell viability. Given that the onset of cell death in torpedo embryos is not preceded by any obvious defects in mitogenesis, the establishment of cell identities or the maintenance of gene expression, it is possible that torpedo transduces a signal necessary for cell survival per se during early embryogenesis. During late embryogenesis, torpedo may mediate the reception of a second signal which

  17. 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.

  18. Intestinal colonization by Candida albicans alters inflammatory responses in Bruton's tyrosine kinase-deficient mice.

    Directory of Open Access Journals (Sweden)

    Karin Strijbis

    Full Text Available The commensal yeast Candida albicans is part of the human intestinal microflora and is considered a "pathobiont", a resident microbe with pathogenic potential yet harmless under normal conditions. The aim of this study was to investigate the effect of C. albicans on inflammation of the intestinal tract and the role of Bruton's tyrosine kinase (Btk. Btk is an enzyme that modulates downstream signaling of multiple receptors involved in innate and adaptive immunity, including the major anti-fungal receptor Dectin-1. Colitis was induced in wild type and Btk-/- mice by treatment with dextran sodium sulfate (DSS and the gastrointestinal tract of selected treatment groups were then colonized with C. albicans. Colonization by C. albicans neither dampened nor exacerbated inflammation in wild type mice, but colon length and spleen weight were improved in Btk-deficient mice colonized with C. albicans. Neutrophil infiltration was comparable between wild type and Btk-/- mice, but the knockout mice displayed severely reduced numbers of macrophages in the colon during both DSS and DSS/Candida treatment. Smaller numbers and reduced responsiveness of Btk-/- macrophages might partially explain the improved colon length of Btk-/- mice as a result of Candida colonization. Surprisingly, DSS/Candida-treated Btk-/- animals had higher levels of certain pro-inflammatory cytokines and levels of the anti-inflammatory cytokine TGF-β were reduced compared to wild type. A clustering and correlation analysis showed that for wild type animals, spleen TGF-β and colon IL-10 and for Btk-/- spleen and colon levels of IL-17A best correlated with the inflammatory parameters. We conclude that in Btk-/- immunocompromised animals, colonization of the gastrointestinal tract by the commensal yeast C. albicans alters inflammatory symptoms associated with colitis.

  19. The tyrosine kinase inhibitor PD153035: implication of labeling position on radiometabolites formed in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Samen, Erik [Karolinska Pharmacy, Karolinska University Hospital Solna, SE-17176 Stockholm (Sweden); Thorell, Jan-Olov [Karolinska Pharmacy, Karolinska University Hospital Solna, SE-17176 Stockholm (Sweden); Fredriksson, Anna [Karolinska Pharmacy, Karolinska University Hospital Solna, SE-17176 Stockholm (Sweden); Stone-Elander, Sharon [Karolinska Pharmacy, Karolinska University Hospital Solna, SE-17176 Stockholm (Sweden) and Department Clinical Neurosciences, Karolinska Institutet, Karolinska University Hospital Solna, SE-17176 Stockholm (Sweden)]. E-mail: sharon.stone-elander@karolinska.se

    2006-11-15

    Introduction: The epidermal growth factor receptor is highly expressed in several types of cancers. Molecules with high affinity to its intracellular tyrosine kinase domain are being developed as in vivo imaging probes. The 4-anilinoquinazoline PD153035 has promising in vitro and in vivo properties for development as a reversible radioligand. Labeling it with carbon-11 in either of its two methoxy positions can potentially give rise to different radiometabolites and, consequently, different imaging capabilities. An evaluation of the radiotracers' metabolism was needed to determine the potential significance of the labeling position. Methods: PD153035 was labeled in the 6- and 7-O-methoxy positions by reacting the corresponding O-desmethyl precursors with [{sup 11}C]methyl iodide. The two radiolabeled compounds were each incubated for 1 h with human and rat liver microsomes. At five time points, the radiolabeled metabolites were examined using radio-liquid chromatography. One metabolite was isolated and subjected to mass spectroscopic analysis. Results: A major polar metabolite was obtained in all incubations. Its molecular weight was consistent with an addition of oxygen, and its fragmentation was consistent with an N-oxidation rather than an aromatic hydroxylation. Regioselective 7-O-dealkylation was also observed, albeit in substantial amounts only in the assay using human microsomes. Conclusions: Radiolabeling in the 7-O-methoxy position is advocated, since the labeled metabolites produced in the 7-O-demethylation are polar and probably rapidly cleared. The differences observed in the incubations with rat and human microsomes suggest that in vivo positron emission tomography studies with {sup 11}C-labeled PD153035 in rodents may not be directly predictive for studies in humans.

  20. The expression andprognostic value ofprotein tyrosine kinase 6 inearly-stage cervical squamous cell cancer

    Institute of Scientific and Technical Information of China (English)

    XiaoJingWang; YingXiong; ZeBiaoMa; JianChuanXia; YanFangLi

    2016-01-01

    Background:Protein tyrosine kinase 6 (PTK6) is overexpressed in many epithelial tumors and predicts poor progno‑sis. However, PTK6 expression status and its role in cervical squamous cell cancer are unknown. This study aimed to investigate the expression level and clinical signiifcance of PTK6 in early‑stage cervical squamous cell cancer. Methods:Quantitative reverse transcription‑polymerase chain reaction (qRT‑PCR) and western blotting analysis were performed to detect PTK6 mRNA and protein expression levels in 10 freshly frozen, early‑stage cervical squamous cell cancer specimens and adjacent non‑tumorous cervical tissues. The expression of PTK6 was detected using immuno‑histochemical staining in 150 formalin‑ifxed, paraffn‑embedded, early‑stage cervical squamous cell cancer sections and 10 normal cervical tissue sections. Results:The mRNA and protein levels of PTK6 in cancer tissues were higher than those in adjacent non‑tumorous cervical tissues. Immunohistochemical analysis showed that PTK6 was not expressed in normal cervical tissues but was overexpressed in the cytoplasm of cervical squamous cell cancer cells. The level of PTK6 expression was signiif‑cantly associated with tumor grade (P=0.020). The 5‑year overall survival rate of patients with high PTK6 expression was lower than that of patients with low PTK6 expression (81.3% vs. 96.2%,P=0.008). Multivariate Cox regression analysis showed that the expression level of PTK6 in cervical squamous cell cancer was an independent prognostic factor for patient survival (hazard ratio=5.999, 95% conifdence interval 1.622–22.191,P Conclusions:PTK6 is overexpressed in cervical squamous cell cancer. Increased PTK6 expression is associated with reduced 5‑year overall survival. PTK6 expression is an independent prognostic predictor for cervical cancer.

  1. Combined effects of EGFR tyrosine kinase inhibitors and vATPase inhibitors in NSCLC cells

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hyeon-Ok [KIRAMS Radiation Biobank, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Hong, Sung-Eun [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Kim, Chang Soon [Department of Microbiological Engineering, Kon-Kuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143–701 (Korea, Republic of); Park, Jin-Ah; Kim, Jin-Hee; Kim, Ji-Young; Kim, Bora [KIRAMS Radiation Biobank, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Chang, Yoon Hwan; Hong, Seok-Il; Hong, Young Jun [Department of Laboratory Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Park, In-Chul, E-mail: parkic@kirams.re.kr [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Lee, Jin Kyung, E-mail: jklee@kirams.re.kr [KIRAMS Radiation Biobank, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Department of Laboratory Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of)

    2015-08-15

    Despite excellent initial clinical responses of non-small cell lung cancer (NSCLC) patients to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), many patients eventually develop resistance. According to a recent report, vacuolar H + ATPase (vATPase) is overexpressed and is associated with chemotherapy drug resistance in NSCLC. We investigated the combined effects of EGFR TKIs and vATPase inhibitors and their underlying mechanisms in the regulation of NSCLC cell death. We found that combined treatment with EGFR TKIs (erlotinib, gefitinib, or lapatinib) and vATPase inhibitors (bafilomycin A1 or concanamycin A) enhanced synergistic cell death compared to treatments with each drug alone. Treatment with bafilomycin A1 or concanamycin A led to the induction of Bnip3 expression in an Hif-1α dependent manner. Knock-down of Hif-1α or Bnip3 by siRNA further enhanced cell death induced by bafilomycin A1, suggesting that Hif-1α/Bnip3 induction promoted resistance to cell death induced by the vATPase inhibitors. EGFR TKIs suppressed Hif-1α and Bnip3 expression induced by the vATPase inhibitors, suggesting that they enhanced the sensitivity of the cells to these inhibitors by decreasing Hif-1α/Bnip3 expression. Taken together, we conclude that EGFR TKIs enhance the sensitivity of NSCLC cells to vATPase inhibitors by decreasing Hif-1α/Bnip3 expression. We suggest that combined treatment with EGFR TKIs and vATPase inhibitors is potentially effective for the treatment of NSCLC. - Highlights: • Co-treatment with EGFR TKIs and vATPase inhibitors induces synergistic cell death • EGFR TKIs enhance cell sensitivity to vATPase inhibitors via Hif-1α downregulation • Co-treatment of these inhibitors is potentially effective for the treatment of NSCLC.

  2. Caveolin-1 modulates cardiac gap junction homeostasis and arrhythmogenecity by regulating cSrc tyrosine kinase.

    Science.gov (United States)

    Yang, Kai-Chien; Rutledge, Cody A; Mao, Mao; Bakhshi, Farnaz R; Xie, An; Liu, Hong; Bonini, Marcelo G; Patel, Hemal H; Minshall, Richard D; Dudley, Samuel C

    2014-08-01

    Genome-wide association studies have revealed significant association of caveolin-1 (Cav1) gene variants with increased risk of cardiac arrhythmias. Nevertheless, the mechanism for this linkage is unclear. Using adult Cav1(-/-) mice, we revealed a marked reduction in the left ventricular conduction velocity in the absence of myocardial Cav1, which is accompanied with increased inducibility of ventricular arrhythmias. Further studies demonstrated that loss of Cav1 leads to the activation of cSrc tyrosine kinase, resulting in the downregulation of connexin 43 and subsequent electric abnormalities. Pharmacological inhibition of cSrc mitigates connexin 43 downregulation, slowed conduction, and arrhythmia inducibility in Cav1(-/-) animals. Using a transgenic mouse model with cardiac-specific overexpression of angiotensin-converting enzyme (ACE8/8), we demonstrated that, on enhanced cardiac renin-angiotensin system activity, Cav1 dissociated from cSrc because of increased Cav1 S-nitrosation at Cys(156), leading to cSrc activation, connexin 43 reduction, impaired gap junction function, and subsequent increase in the propensity for ventricular arrhythmias and sudden cardiac death. Renin-angiotensin system-induced Cav1 S-nitrosation was associated with increased Cav1-endothelial nitric oxide synthase binding in response to increased mitochondrial reactive oxidative species generation. The present studies reveal the critical role of Cav1 in modulating cSrc activation, gap junction remodeling, and ventricular arrhythmias. These data provide a mechanistic explanation for the observed genetic link between Cav1 and cardiac arrhythmias in humans and suggest that targeted regulation of Cav1 may reduce arrhythmic risk in cardiac diseases associated with renin-angiotensin system activation. © 2014 American Heart Association, Inc.

  3. Removal of Soluble Fms-Like Tyrosine Kinase-1 by Dextran Sulfate Apheresis in Preeclampsia.

    Science.gov (United States)

    Thadhani, Ravi; Hagmann, Henning; Schaarschmidt, Wiebke; Roth, Bernhard; Cingoez, Tuelay; Karumanchi, S Ananth; Wenger, Julia; Lucchesi, Kathryn J; Tamez, Hector; Lindner, Tom; Fridman, Alexander; Thome, Ulrich; Kribs, Angela; Danner, Marco; Hamacher, Stefanie; Mallmann, Peter; Stepan, Holger; Benzing, Thomas

    2016-03-01

    Preeclampsia is a devastating complication of pregnancy. Soluble Fms-like tyrosine kinase-1 (sFlt-1) is an antiangiogenic protein believed to mediate the signs and symptoms of preeclampsia. We conducted an open pilot study to evaluate the safety and potential efficacy of therapeutic apheresis with a plasma-specific dextran sulfate column to remove circulating sFlt-1 in 11 pregnant women (20-38 years of age) with very preterm preeclampsia (23-32 weeks of gestation, systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg, new onset protein/creatinine ratio >0.30 g/g, and sFlt-1/placental growth factor ratio >85). We evaluated the extent of sFlt-1 removal, proteinuria reduction, pregnancy continuation, and neonatal and fetal safety of apheresis after one (n=6), two (n=4), or three (n=1) apheresis treatments. Mean sFlt-1 levels were reduced by 18% (range 7%-28%) with concomitant reductions of 44% in protein/creatinine ratios. Pregnancy continued for 8 days (range 2-11) and 15 days (range 11-21) in women treated once and multiple times, respectively, compared with 3 days (range 0-14) in untreated contemporaneous preeclampsia controls (n=22). Transient maternal BP reduction during apheresis was managed by withholding pre-apheresis antihypertensive therapy, saline prehydration, and reducing blood flow through the apheresis column. Compared with infants born prematurely to untreated women with and without preeclampsia (n=22 per group), no adverse effects of apheresis were observed. In conclusion, therapeutic apheresis reduced circulating sFlt-1 and proteinuria in women with very preterm preeclampsia and appeared to prolong pregnancy without major adverse maternal or fetal consequences. A controlled trial is warranted to confirm these findings.

  4. Increased expression of Bruton's tyrosine kinase in peripheral blood is associated with lupus nephritis.

    Science.gov (United States)

    Kong, Wei; Deng, Wei; Sun, Yue; Huang, Saisai; Zhang, Zhuoya; Shi, Bingyu; Chen, Weiwei; Tang, Xiaojun; Yao, Genhong; Feng, Xuebing; Sun, Lingyun

    2017-06-14

    Systemic lupus erythematosus (SLE) is an autoimmune disease manifested by multiorgan impairment. It is reported that B cells participate in the onset of SLE. Bruton's tyrosine kinase (Btk), as a downstream signaling molecule of B cell antigen receptor (BCR) signaling pathway, is involved in the development, activation, and survival of B cells. The aim of our study was to explore the specific role of Btk in lupus nephritis (LN). We determined the percentages of Btk+ B cells in peripheral blood mononuclear cells (PBMCs) from SLE patients by flow cytometry and analyzed the correlation between the percentage of Btk+ B cells and lupus-related clinical indexes. Immunohistochemistry was used to detect the Btk expression in kidney from LN patients and tumor surrounding tissues. Compared with controls, the frequency of Btk+ B cells in SLE patients was upregulated (p < 0.01), and it was significantly correlated with the SLE Disease Activity Index (SLEDAI) (p < 0.01), levels of plasma anti-dsDNA antibody (p < 0.05), the amount of 24-h urine protein (p < 0.05), and levels of plasma C3 (p < 0.05). The frequency of Btk+ B cells in the patients with LN was significantly higher than those without LN (p < 0.05). Although the Btk expression in glomerulus of LN patients was significantly increased compared with controls (p < 0.001), but it had no correlation with the renal pathology activity index, SLEDAI, or 24-h urine protein. In conclusion, the increased expression of Btk in peripheral blood was correlated with LN, indicating that it may be a therapeutic target for SLE.

  5. Enhanced Bruton's Tyrosine Kinase Activity in Peripheral Blood B Lymphocytes From Patients With Autoimmune Disease.

    Science.gov (United States)

    Corneth, Odilia B J; Verstappen, Gwenny M P; Paulissen, Sandra M J; de Bruijn, Marjolein J W; Rip, Jasper; Lukkes, Melanie; van Hamburg, Jan Piet; Lubberts, Erik; Bootsma, Hendrika; Kroese, Frans G M; Hendriks, Rudi W

    2017-06-01

    Bruton's tyrosine kinase (BTK) transmits crucial survival signals from the B cell receptor (BCR) in B cells. Pharmacologic BTK inhibition effectively diminishes disease symptoms in mouse models of autoimmunity; conversely, transgenic BTK overexpression induces systemic autoimmunity in mice. We undertook this study to investigate BTK expression and activity in human B cells in the context of autoimmune disease. Using intracellular flow cytometry, we quantified BTK expression and phosphorylation in subsets of peripheral blood B cells from 30 patients with rheumatoid arthritis (RA), 26 patients with primary Sjögren's syndrome (SS), and matched healthy controls. In circulating B cells, BTK protein expression levels correlated with BTK phosphorylation. BTK expression was up-regulated upon BCR stimulation in vitro and was significantly higher in CD27+ memory B cells than in CD27-IgD+ naive B cells. Importantly, BTK protein and phospho-BTK were significantly increased in B cells from anti-citrullinated protein antibody (ACPA)-positive RA patients but not in B cells from ACPA-negative RA patients. BTK was increased both in naive B cells and in memory B cells and correlated with frequencies of circulating CCR6+ Th17 cells. Likewise, BTK protein was increased in B cells from a major fraction of patients with primary SS and correlated with serum rheumatoid factor levels and parotid gland T cell infiltration. Interestingly, targeting T cell activation in patients with primary SS using the CTLA-4Ig fusion protein abatacept restored BTK protein expression in B cells to normal levels. These data indicate that autoimmune disease in humans is characterized by enhanced BTK activity, which is linked not only to autoantibody formation but also to T cell activity. © 2017, American College of Rheumatology.

  6. Role of Bruton’s Tyrosine Kinase inhibitors in HIV-1 infected cells

    Science.gov (United States)

    Guendel, Irene; Iordanskiy, Sergey; Sampey, Gavin C; Van Duyne, Rachel; Calvert, Valerie; Petricoin, Emanuel; Saifuddin, Mohammed; Kehn-Hall, Kylene; Kashanchi, Fatah

    2015-01-01

    Many cellular cofactors have been documented to be critical for various stages of viral replication. Using high throughput proteomic assays, we have previously identified Bruton’s tyrosine kinase (BTK) as a host protein that was uniquely up-regulated in the plasma membrane of HIV-1 infected T-cells. Here, we have further characterized the BTK expression in HIV-1 infection and show that this cellular factor is specifically expressed in infected myeloid cells. Significant up-regulation of the phosphorylated form of BTK was observed in infected cells. Using size exclusion chromatography, we found BTK to be virtually absent in the uninfected U937 cells, however new BTK protein complexes were identified and distributed in both high molecular weight (~600 kDa) and a small molecular weight complex (~60–120 kDa) in the infected U1 cells. BTK levels were highest in cells either chronically expressing virus or induced/infected myeloid cells and that BTK translocated to the membrane following induction of the infected cells. BTK knockdown in HIV-1 infected cells using siRNA resulted in selective death of infected, but not uninfected, cells. Using BTK specific antibody and small molecule inhibitors including LFM-A13 and a FDA approved compound, Ibrutinib (PCI – 32765), we have found that HIV-1 infected cells are sensitive to apoptotic cell death and result in a decrease in virus production. Overall, our data suggests that HIV-1 infected cells are sensitive to treatments targeting BTK expressed in infected cells. PMID:25672887

  7. Bruton's tyrosine kinase mediated signaling enhances leukemogenesis in a mouse model for chronic lymphocytic leukemia.

    Science.gov (United States)

    Kil, Laurens P; de Bruijn, Marjolein Jw; van Hulst, Jennifer Ac; Langerak, Anton W; Yuvaraj, Saravanan; Hendriks, Rudi W

    2013-01-01

    In chronic lymphocytic leukemia (CLL) signals from the B cell receptor (BCR) play a major role in disease development and progression. In this light, new therapies that specifically target signaling molecules downstream of the BCR continue to be developed. While first studies on the selective small molecule inhibitor of Bruton's tyrosine kinase (Btk), Ibrutinib (PCI-32765), demonstrated that Btk inhibition sensitizes CLL cells to apoptosis and alters their migratory behavior, these studies however did not address whether Btk-mediated signaling is involved in the process of CLL leukemogenesis. To investigate the requirement of Btk signaling for CLL development, we modulated Btk expression in the IgH.ETμ CLL mouse model, which is based on sporadic expression of the simian oncovirus SV40 T-antigen in mature B cells. To this end, we crossed IgH.ETμ mice on a Btk-deficient background or introduced a human Btk transgene (CD19-hBtk). Here we show that Btk deficiency fully abrogates CLL formation in IgH.ETμ mice, and that leukemias formed in Btk haplo-insufficient mice selectively expressed the wild-type Btk allele on their active X chromosome. Conversely, Btk overexpression accelerated CLL onset, increased mortality, and was associated with selection of non-stereotypical BCRs into CLL clones. Taken together, these data show that Btk expression represents an absolute prerequisite for CLL development and that Btk mediated signaling enhances leukemogenesis in mice. We therefore conclude that in CLL Btk expression levels set the threshold for malignant transformation.

  8. Amplification of IL-21 signalling pathway through Bruton's tyrosine kinase in human B cell activation.

    Science.gov (United States)

    Wang, Sheau-Pey; Iwata, Shigeru; Nakayamada, Shingo; Niiro, Hiroaki; Jabbarzadeh-Tabrizi, Siamak; Kondo, Masahiro; Kubo, Satoshi; Yoshikawa, Maiko; Tanaka, Yoshiya

    2015-08-01

    B cells play an important role in the pathogenesis of autoimmune diseases. The role of Bruton's tyrosine kinase (Btk) in cytokine-induced human B cell differentiation and class-switch recombination remains incompletely defined. This study analysed the effect of Btk on human activated B cells. Purified B cells from healthy subjects were stimulated with B cell receptor (BCR) and other stimuli with or without a Btk inhibitor and gene expression was measured. The B cell line BJAB was used to assess Btk-associated signalling cascades. Phosphorylated Btk (p-Btk) in peripheral blood B cells obtained from 10 healthy subjects and 41 patients with RA was measured by flow cytometry and compared with patient backgrounds. IL-21 signalling, in concert with BCR, CD40 and BAFF signals, led to robust expression of differentiation- and class-switch DNA recombination-related genes and IgG production in human B cells, all of which were significantly suppressed by the Btk inhibitor. Although phosphorylation of STAT1 and STAT3 was induced by co-stimulation with IL-21, BCR and CD40, STAT1 phosphorylation in the nucleus, but not in the cytoplasm, was exclusively impaired by Btk blockade. High levels of p-Btk were noted in B cells of RA patients compared with controls and they correlated significantly with titres of RF among RF-positive patients. The findings elucidate a model in which Btk not only plays a fundamental role in the regulation of BCR signalling, but may also mediate crosstalk with cytokine signalling pathways through regulation of IL-21-induced phosphorylation of STAT1 in the nuclei of human B cells. Btk appears to have pathological relevance in RA. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Role of Bruton's tyrosine kinase inhibitors in HIV-1-infected cells.

    Science.gov (United States)

    Guendel, Irene; Iordanskiy, Sergey; Sampey, Gavin C; Van Duyne, Rachel; Calvert, Valerie; Petricoin, Emanuel; Saifuddin, Mohammed; Kehn-Hall, Kylene; Kashanchi, Fatah

    2015-06-01

    Many cellular cofactors have been documented to be critical for various stages of viral replication. Using high-throughput proteomic assays, we have previously identified Bruton's tyrosine kinase (BTK) as a host protein that was uniquely upregulated in the plasma membrane of human immunodeficiency virus (HIV-1)-infected T cells. Here, we have further characterized the BTK expression in HIV-1 infection and show that this cellular factor is specifically expressed in infected myeloid cells. Significant upregulation of the phosphorylated form of BTK was observed in infected cells. Using size exclusion chromatography, we found BTK to be virtually absent in the uninfected U937 cells; however, new BTK protein complexes were identified and distributed in both high molecular weight (∼600 kDa) and a small molecular weight complex (∼60-120 kDa) in the infected U1 cells. BTK levels were highest in cells either chronically expressing virus or induced/infected myeloid cells and that BTK translocated to the membrane following induction of the infected cells. BTK knockdown in HIV-1-infected cells using small interfering RNA (siRNA) resulted in selective death of infected, but not uninfected, cells. Using BTK-specific antibody and small-molecule inhibitors including LFM-A13 and a FDA-approved compound, ibrutinib (PCI-32765), we have found that HIV-1-infected cells are sensitive to apoptotic cell death and result in a decrease in virus production. Overall, our data suggests that HIV-1-infected cells are sensitive to treatments targeting BTK expressed in infected cells.

  10. Ibrutinib, a Bruton's tyrosine kinase inhibitor, exhibits antitumoral activity and induces autophagy in glioblastoma.

    Science.gov (United States)

    Wang, Jin; Liu, Xiaoyang; Hong, Yongzhi; Wang, Songtao; Chen, Pin; Gu, Aihua; Guo, Xiaoyuan; Zhao, Peng

    2017-07-17

    Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adults. Ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor, is a novel anticancer drug used for treating several types of cancers. In this study, we aimed to determine the role of ibrutinib on GBM. Cell proliferation was determined by using cell viability, colony formation, and 5-ethynyl-2'-deoxyuridine (EdU) assays. Cell cycle and cell apoptosis were analyzed by flow cytometry. Cell migratory ability was evaluated by wound healing assays and trans-well migration assays. ATG7 expression was knocked-down by transfection with Atg7-specific small interfering RNA. Overexpression of active Akt protein was achieved by transfecting the cells with a plasmid expressing constitutively active Akt (CA-Akt). Transmission electron microscopy was performed to examine the formation of autophagosomes in cells. Immunofluorescence and western blot analyses were used to analyze protein expression. Tumor xenografts in nude mice and immunohistochemistry were performed to evaluate the effect of ibrutinib on tumor growth in vivo. Ibrutinib inhibited cellular proliferation and migration, and induced apoptosis and autophagy in LN229 and U87 cells. Overexpression of the active Akt protein decreased ibrutinib-induced autophagy, while inhibiting Akt by LY294002 treatment enhanced ibrutinib-induced autophagy. Specific inhibition of autophagy by 3-methyladenine (3MA) or Atg7 targeting with small interfering RNA (si-Atg7) enhanced the anti-GBM effect of ibrutinib in vitro and in vivo. Our results indicate that ibrutinib exerts a profound antitumor effect and induces autophagy through Akt/mTOR signaling pathway in GBM cells. Autophagy inhibition promotes the antitumor activity of ibrutinib in GBM. Our findings provide important insights into the action of an anticancer agent combining with autophagy inhibitor for malignant glioma.

  11. The Bruton's tyrosine kinase inhibitor ibrutinib exerts immunomodulatory effects through regulation of tumor-infiltrating macrophages.

    Science.gov (United States)

    Ping, Lingyan; Ding, Ning; Shi, Yunfei; Feng, Lixia; Li, Jiao; Liu, Yalu; Lin, Yufu; Shi, Cunzhen; Wang, Xing; Pan, Zhengying; Song, Yuqin; Zhu, Jun

    2017-06-13

    The Bruton's tyrosine kinase (Btk) inhibitor ibrutinib has demonstrated promising efficacy in a variety of hematologic malignancies. However, the precise mechanism of action of the drug remains to be fully elucidated. Tumor-infiltrating macrophages presented in the tumor microenvironment have been shown to promote development and progression of B-cell lymphomas through crosstalk mediated by secreted cytokines and chemokines. Because Btk has been implicated in Toll-like receptor (TLR) signaling pathways that regulate macrophage activation and production of proinflammatory cytokines, we investigated the immunomodulatory effects of Btk inhibitor on macrophages. Our results demonstrate that Btk inhibition efficiently suppresses production of CXCL12, CXCL13, CCL19, and VEGF by macrophages. Furthermore, attenuated secretion of homeostatic chemokines from Btk inhibitor-treated macrophages significantly compromise adhesion, invasion, and migration of lymphoid malignant cells and even those not driven by Btk expression. The supernatants from Btk inhibitor-treated macrophages also impair the ability of endothelial cells to undergo angiogenic tube formation. Mechanistic analysis revealed that Btk inhibitors treatment downregulates secretion of homeostatic chemokines and cytokines through inactivation of Btk signaling and the downstream transcription factors, NF-κB, STAT3, and AP-1. Taken together, these results suggest that the encouraging therapeutic efficacy of Btk inhibitor may be due to both direct cytotoxic effects on malignant B cells and immunomodulatory effects on macrophages present in the tumor microenvironment. This novel mechanism of action suggests that, in addition to B-cell lymphomas, Btk inhibitor may also have therapeutic value in lymphatic malignancies and solid tumors lacking Btk expression.

  12. Role of Bruton’s tyrosine kinase in myeloma cell migration and induction of bone disease

    Science.gov (United States)

    Bam, Rakesh; Ling, Wen; Khan, Sharmin; Pennisi, Angela; Venkateshaiah, Sathisha Upparahalli; Li, Xin; van Rhee, Frits; Usmani, Saad; Barlogie, Bart; Shaughnessy, John; Epstein, Joshua; Yaccoby, Shmuel

    2014-01-01

    Myeloma cells typically grow in bone, recruit osteoclast precursors and induce their differentiation and activity in areas adjacent to tumor foci. Bruton’s tyrosine kinase (BTK), of the TEC family, is expressed in hematopoietic cells and is particularly involved in B-lymphocyte function and osteoclastogenesis. We demonstrated BTK expression in clinical myeloma plasma cells, interleukin (IL) –6– or stroma–dependent cell lines and osteoclasts. SDF-1 induced BTK activation in myeloma cells and BTK inhibition by small hairpin RNA or the small molecule inhibitor, LFM-A13, reduced their migration toward stromal cell-derived factor-1 (SDF-1). Pretreatment with LFM-A13 also reduced in vivo homing of myeloma cells to bone using bioluminescence imaging in the SCID-rab model. Enforced expression of BTK in myeloma cell line enhanced cell migration toward SDF-1 but had no effect on short-term growth. BTK expression was correlated with cell-surface CXCR4 expression in myeloma cells (n = 33, r = 0.81, P < 0.0001), and BTK gene and protein expression was more profound in cell-surface CXCR4-expressing myeloma cells. BTK was not upregulated by IL-6 while its inhibition had no effect on IL-6 signaling in myeloma cells. Human osteoclast precursors also expressed BTK and cell-surface CXCR4 and migrated toward SDF-1. LFM-A13 suppressed migration and differentiation of osteoclast precursors as well as bone-resorbing activity of mature osteoclasts. In primary myeloma-bearing SCID-rab mice, LFM-A13 inhibited osteoclast activity, prevented myeloma-induced bone resorption and moderately suppressed myeloma growth. These data demonstrate BTK and cell-surface CXCR4 association in myeloma cells and that BTK plays a role in myeloma cell homing to bone and myeloma-induced bone disease. PMID:23456977

  13. Intestinal colonization by Candida albicans alters inflammatory responses in Bruton's tyrosine kinase-deficient mice.

    Science.gov (United States)

    Strijbis, Karin; Yilmaz, Omer H; Dougan, Stephanie K; Esteban, Alexandre; Gröne, Andrea; Kumamoto, Carol A; Ploegh, Hidde L

    2014-01-01

    The commensal yeast Candida albicans is part of the human intestinal microflora and is considered a "pathobiont", a resident microbe with pathogenic potential yet harmless under normal conditions. The aim of this study was to investigate the effect of C. albicans on inflammation of the intestinal tract and the role of Bruton's tyrosine kinase (Btk). Btk is an enzyme that modulates downstream signaling of multiple receptors involved in innate and adaptive immunity, including the major anti-fungal receptor Dectin-1. Colitis was induced in wild type and Btk-/- mice by treatment with dextran sodium sulfate (DSS) and the gastrointestinal tract of selected treatment groups were then colonized with C. albicans. Colonization by C. albicans neither dampened nor exacerbated inflammation in wild type mice, but colon length and spleen weight were improved in Btk-deficient mice colonized with C. albicans. Neutrophil infiltration was comparable between wild type and Btk-/- mice, but the knockout mice displayed severely reduced numbers of macrophages in the colon during both DSS and DSS/Candida treatment. Smaller numbers and reduced responsiveness of Btk-/- macrophages might partially explain the improved colon length of Btk-/- mice as a result of Candida colonization. Surprisingly, DSS/Candida-treated Btk-/- animals had higher levels of certain pro-inflammatory cytokines and levels of the anti-inflammatory cytokine TGF-β were reduced compared to wild type. A clustering and correlation analysis showed that for wild type animals, spleen TGF-β and colon IL-10 and for Btk-/- spleen and colon levels of IL-17A best correlated with the inflammatory parameters. We conclude that in Btk-/- immunocompromised animals, colonization of the gastrointestinal tract by the commensal yeast C. albicans alters inflammatory symptoms associated with colitis.

  14. Hepatocellular Toxicity Associated with Tyrosine Kinase Inhibitors: Mitochondrial Damage and Inhibition of Glycolysis

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    Franziska Paech

    2017-06-01

    Full Text Available Tyrosine kinase inhibitors (TKIs are anticancer drugs with a lesser toxicity than classical chemotherapeutic agents but still with a narrow therapeutic window. While hepatotoxicity is known for most TKIs, underlying mechanisms remain mostly unclear. We therefore aimed at investigating mechanisms of hepatotoxicity for imatinib, sunitinib, lapatinib and erlotinib in vitro. We treated HepG2 cells, HepaRG cells and mouse liver mitochondria with TKIs (concentrations 1–100 μM for different periods of time and assessed toxicity. In HepG2 cells maintained with glucose (favoring glycolysis, all TKIs showed a time- and concentration-dependent cytotoxicity and, except erlotinib, a drop in intracellular ATP. In the presence of galactose (favoring mitochondrial metabolism, imatinib, sunitinib and erlotinib showed a similar toxicity profile as for glucose whereas lapatinib was less toxic. For imatinib, lapatinib and sunitinib, cytotoxicity increased in HepaRG cells induced with rifampicin, suggesting formation of toxic metabolites. In contrast, erlotinib was more toxic in HepaRG cells under basal than CYP-induced conditions. Imatinib, sunitinib and lapatinib reduced the mitochondrial membrane potential in HepG2 cells and in mouse liver mitochondria. In HepG2 cells, these compounds increased reactive oxygen species production, impaired glycolysis, and induced apoptosis. In addition, imatinib and sunitinib impaired oxygen consumption and activities of complex I and III (only imatinib, and reduced the cellular GSH pool. In conclusion, imatinib and sunitinib are mitochondrial toxicants after acute and long-term exposure and inhibit glycolysis. Lapatinib affected mitochondria only weakly and inhibited glycolysis, whereas the cytotoxicity of erlotinib could not be explained by a mitochondrial mechanism.

  15. Ror family receptor tyrosine kinases regulate the maintenance of neural progenitor cells in the developing neocortex.

    Science.gov (United States)

    Endo, Mitsuharu; Doi, Ryosuke; Nishita, Michiru; Minami, Yasuhiro

    2012-04-15

    The Ror family receptor tyrosine kinases (RTKs), Ror1 and Ror2, have been shown to play crucial roles in developmental morphogenesis by acting as receptors or co-receptors to mediate Wnt5a-induced signaling. Although Ror1, Ror2 and Wnt5a are expressed in the developing brain, little is known about their roles in the neural development. Here we show that Ror1, Ror2 and their ligand Wnt5a are highly expressed in neocortical neural progenitor cells (NPCs). Small interfering RNA (siRNA)-mediated suppression of Ror1, Ror2 or Wnt5a in cultured NPCs isolated from embryonic neocortex results in the reduction of βIII-tubulin-positive neurons that are produced from NPCs possibly through the generation of T-box brain 2 (Tbr2)-positive intermediate progenitors. BrdU-labeling experiments further reveal that the proportion of proliferative and neurogenic NPCs, which are positive for neural progenitor cell marker (Pax6) but negative for glial cell marker (glial fibrillary acidic protein; GFAP), is reduced within a few days in culture following knockdown of these molecules, suggesting that Ror1, Ror2 and Wnt5a regulate neurogenesis through the maintenance of NPCs. Moreover, we show that Dishevelled 2 (Dvl2) is involved in Wnt5a-Ror1 and Wnt5a-Ror2 signaling in NPCs, and that suppressed expression of Dvl2 indeed reduces the proportion of proliferative and neurogenic NPCs. Interestingly, suppressed expression of either Ror1 or Ror2 in NPCs in the developing neocortex results in the precocious differentiation of NPCs into neurons, and their forced expression results in delayed differentiation. Collectively, these results indicate that Wnt5a-Ror1 and Wnt5a-Ror2 signaling pathways play roles in maintaining proliferative and neurogenic NPCs during neurogenesis of the developing neocortex.

  16. 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.

  17. Alignment independent 3D-QSAR, quantum calculations and molecular docking of Mer specific tyrosine kinase inhibitors as anticancer drugs

    Directory of Open Access Journals (Sweden)

    Fereshteh Shiri

    2016-03-01

    Full Text Available Mer receptor tyrosine kinase is a promising novel cancer therapeutic target in many human cancers, because abnormal activation of Mer has been implicated in survival signaling and chemoresistance. 3D-QSAR analyses based on alignment independent descriptors were performed on a series of 81 Mer specific tyrosine kinase inhibitors. The fractional factorial design (FFD and the enhanced replacement method (ERM were applied and tested as variable selection algorithms for the selection of optimal subsets of molecular descriptors from a much greater pool of such regression variables. The data set was split into 65 molecules as the training set and 16 compounds as the test set. All descriptors were generated by using the GRid INdependent descriptors (GRIND approach. After variable selection, GRIND were correlated with activity values (pIC50 by PLS regression. Of the two applied variable selection methods, ERM had a noticeable improvement on the statistical parameters of PLS model, and yielded a q2 value of 0.77, an rpred2 of 0.94, and a low RMSEP value of 0.25. The GRIND information contents influencing the affinity on Mer specific tyrosine kinase were also confirmed by docking studies. In a quantum calculation study, the energy difference between HOMO and LUMO (gap implied the high interaction of the most active molecule in the active site of the protein. In addition, the molecular electrostatic potential energy at DFT level confirmed results obtained from the molecular docking. The identified key features obtained from the molecular modeling, enabled us to design novel kinase inhibitors.

  18. The Physarum polycephalum Genome Reveals Extensive Use of Prokaryotic Two-Component and Metazoan-Type Tyrosine Kinase Signaling.

    Science.gov (United States)

    Schaap, Pauline; Barrantes, Israel; Minx, Pat; Sasaki, Narie; Anderson, Roger W; Bénard, Marianne; Biggar, Kyle K; Buchler, Nicolas E; Bundschuh, Ralf; Chen, Xiao; Fronick, Catrina; Fulton, Lucinda; Golderer, Georg; Jahn, Niels; Knoop, Volker; Landweber, Laura F; Maric, Chrystelle; Miller, Dennis; Noegel, Angelika A; Peace, Rob; Pierron, Gérard; Sasaki, Taeko; Schallenberg-Rüdinger, Mareike; Schleicher, Michael; Singh, Reema; Spaller, Thomas; Storey, Kenneth B; Suzuki, Takamasa; Tomlinson, Chad; Tyson, John J; Warren, Wesley C; Werner, Ernst R; Werner-Felmayer, Gabriele; Wilson, Richard K; Winckler, Thomas; Gott, Jonatha M; Glöckner, Gernot; Marwan, Wolfgang

    2015-11-27

    Physarum polycephalum is a well-studied microbial eukaryote with unique experimental attributes relative to other experimental model organisms. It has a sophisticated life cycle with several distinct stages including amoebal, flagellated, and plasmodial cells. It is unusual in switching between open and closed mitosis according to specific life-cycle stages. Here we present the analysis of the genome of this enigmatic and important model organism and compare it with closely related species. The genome is littered with simple and complex repeats and the coding regions are frequently interrupted by introns with a mean size of 100 bases. Complemented with extensive transcriptome data, we define approximately 31,000 gene loci, providing unexpected insights into early eukaryote evolution. We describe extensive use of histidine kinase-based two-component systems and tyrosine kinase signaling, the presence of bacterial and plant type photoreceptors (phytochromes, cryptochrome, and phototropin) and of plant-type pentatricopeptide repeat proteins, as well as metabolic pathways, and a cell cycle control system typically found in more complex eukaryotes. Our analysis characterizes P. polycephalum as a prototypical eukaryote with features attributed to the last common ancestor of Amorphea, that is, the Amoebozoa and Opisthokonts. Specifically, the presence of tyrosine kinases in Acanthamoeba and Physarum as representatives of two distantly related subdivisions of Amoebozoa argues against the later emergence of tyrosine kinase signaling in the opisthokont lineage and also against the acquisition by horizontal gene transfer. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  19. Rescue of a trafficking defective human pacemaker channel via a novel mechanism: roles of Src, Fyn, and Yes tyrosine kinases.

    Science.gov (United States)

    Lin, Yen-Chang; Huang, Jianying; Kan, Hong; Frisbee, Jefferson C; Yu, Han-Gang

    2009-10-30

    Therapeutic strategies such as using channel blockers and reducing culture temperature have been used to rescue some long QT-associated voltage-gated potassium Kv trafficking defective mutant channels. A hyperpolarization-activated cyclic nucleotide-gated HCN4 pacemaker channel mutant (D553N) has been recently found in a patient associated with cardiac arrhythmias including long QT. D553N showed the defective trafficking to the cell surface, leading to little ionic current expression (loss-of-function). We show in this report that enhanced tyrosine phosphorylation mediated by Src, Fyn, and Yes kinases was able to restore the surface expression of D553N for normal current expression. Src or Yes, but not Fyn, significantly increased the current density and surface expression of D553N. Fyn accelerated the activation kinetics of the rescued D553N. Co-expression of D553N with Yes exhibited the slowest activation kinetics of D553N. Src, Fyn, and Yes significantly enhanced the tyrosine phosphorylation of D553N. A combination of Src, Fyn, and Yes rescued the current expression and the gating of D553N comparable with those of wild-type HCN4. In conclusion, we demonstrate a novel mechanism using three endogenous Src kinases to rescue a trafficking defective HCN4 mutant channel (D553N) by enhancing the tyrosine phosphorylation of the mutant channel protein.

  20. 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.

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

    Directory of Open Access Journals (Sweden)

    Meehan Maria

    2012-02-01

    Full Text Available 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. Growth-Factor-Driven Rescue to Receptor Tyrosine Kinase (RTK) Inhibitors through Akt and Erk Phosphorylation in Pediatric Low Grade Astrocytoma and Ependymoma

    NARCIS (Netherlands)

    Sie, Mariska; den Dunnen, Wilfred F. A.; Lourens, Harm Jan; Meeuwsen-de Boer, Tiny G. J.; Scherpen, Frank J. G.; Zomerman, Walderik W.; Kampen, Kim R.; Hoving, Eelco W.; de Bont, Eveline S. J. M.

    2015-01-01

    Up to now, several clinical studies have been started investigating the relevance of receptor tyrosine kinase (RTK) inhibitors upon progression free survival in various pediatric brain tumors. However, single targeted kinase inhibition failed, possibly due to tumor resistance mechanisms. The present

  3. Phase i and pharmacological study of the broad-spectrum tyrosine kinase inhibitor JNJ-26483327 in patients with advanced solid tumours

    NARCIS (Netherlands)

    I.R.H.M. Konings (Inge); M.J.A. de Jonge (Maja); H. Burger (Herman); A. van der Gaast (Ate); L.E.C. van Beijsterveldt (Ludy); H. Winkler; J. Verweij (Jaap); Z. Yuan; P. Hellemans; F.A.L.M. Eskens (Ferry)

    2010-01-01

    textabstractBackground:JNJ-26483327 is an oral, potent, multi-targeted tyrosine kinase inhibitor, inhibiting kinases of epidermal growth factor receptor (EGFR)-1,-2 and-4, rearranged during transfection (RET) receptor, vascular endothelial growth factor receptor (VEGFR)-3 and Src family (Lyn, Fyn,

  4. The tyrosine kinase receptor c-met, its cognate ligand HGF and the tyrosine kinase receptor trasducers STAT3, PI3K and RHO in thyroid nodules associated with Hashimoto's thyroiditis: an immunohistochemical characterization

    Directory of Open Access Journals (Sweden)

    R. M. Ruggeri

    2010-06-01

    Full Text Available Hepatocyte growth factor (HGF exerts proliferative activities in thyrocytes upon binding to its tyrosine kinase receptor c-met and is also expressed in benign thyroid nodules as well as in Hashimoto’s thyroiditis (HT. The simultaneous expression of HGF/c-met and three trasducers of tyrosine kinase receptors (STAT3, PI3K, RHO in both the nodular and extranodular tissues were studied by immunohistochemistry in 50 benign thyroid nodules (NGs, 25 of which associated with HT. The ligand/tyrosine kinase receptor pair HGF/c-met and the two trasducers PI3K and RHO were expressed in NGs, regardless of association with HT, with a higher positive cases percentage in HT-associated NGs compared to not HT-associated NGs (25/25 or 100% vs 7/25 or 28%; P<0.001. HGF, PI3K and RHO expression was only stromal (fibroblasts and endothelial cells, in all 32 reactive NGs, while c-met localization was consistently epithelial (thyrocyes. Immu­noreactions for HGF, c-met, PI3K and RHO were also apparent in the extra-nodular tissue of HT specimens, where HGF and PI3K were expressed not only in stromal cells but also in thyrocyes along with the c-met. Finally, a positive correlation was observed between the proportion of HGF, c-met, PI3K follicular cells and the grade of lymphoid aggregates in HT. In conclusion, HGF, c-met, PI3K are much more frequently and highly expressed in HT compared to NGs, and among all NGs in those present in the context of HT. A paracrine effect of HFG/c-met on nodule development, based on the prevalent stromal expression, may be suggested along with a major role of HGF/c-met and PI3K in HT. Finally, the expression of such molecules in HT may be regulated by lymphoid infiltrate.

  5. NPM-ALK oncogenic tyrosine kinase controls T-cell identity by transcriptional regulation and epigenetic silencing in lymphoma cells.

    Science.gov (United States)

    Ambrogio, Chiara; Martinengo, Cinzia; Voena, Claudia; Tondat, Fabrizio; Riera, Ludovica; di Celle, Paola Francia; Inghirami, Giorgio; Chiarle, Roberto

    2009-11-15

    Transformed cells in lymphomas usually maintain the phenotype of the postulated normal lymphocyte from which they arise. By contrast, anaplastic large cell lymphoma (ALCL) is a T-cell lymphoma with aberrant phenotype because of the defective expression of the T-cell receptor and other T-cell-specific molecules for still undetermined mechanisms. The majority of ALCL carries the translocation t(2;5) that encodes for the oncogenic tyrosine kinase NPM-ALK, fundamental for survival, proliferation, and migration of transformed T cells. Here, we show that loss of T-cell-specific molecules in ALCL cases is broader than reported previously and involves most T-cell receptor-related signaling molecules, including CD3epsilon, ZAP70, LAT, and SLP76. We further show that NPM-ALK, but not the kinase-dead NPM-ALK(K210R), downregulated the expression of these molecules by a STAT3-mediated gene transcription regulation and/or epigenetic silencing because this downregulation was reverted by treating ALCL cells with 5-aza-2-deoxycytidine or by knocking down STAT3 through short hairpin RNA. Finally, NPM-ALK increased the methylation of ZAP70 intron 1-exon 2 boundary region, and both NPM-ALK and STAT3 regulated the expression levels of DNA methyltransferase 1 in transformed T cells. Thus, our data reveal that oncogene-deregulated tyrosine kinase activity controls the expression of molecules that determine T-cell identity and signaling.

  6. Ca2+/Calmodulin and Apo-Calmodulin Both Bind to and Enhance the Tyrosine Kinase Activity of c-Src.

    Directory of Open Access Journals (Sweden)

    Silviya R Stateva

    Full Text Available Src family non-receptor tyrosine kinases play a prominent role in multiple cellular processes, including: cell proliferation, differentiation, cell survival, stress response, and cell adhesion and migration, among others. And when deregulated by mutations, overexpression, and/or the arrival of faulty incoming signals, its hyperactivity contributes to the development of hematological and solid tumors. c-Src is a prototypical member of this family of kinases, which is highly regulated by a set of phosphorylation events. Other factor contributing to the regulation of Src activity appears to be mediated by the Ca2+ signal generated in cells by different effectors, where the Ca2+-receptor protein calmodulin (CaM plays a key role. In this report we demonstrate that CaM directly interacts with Src in both Ca2+-dependent and Ca2+-independent manners in vitro and in living cells, and that the CaM antagonist N-(6-aminohexyl-5-chloro-1-naphthalenesulfonamide (W-7 inhibits the activation of this kinase induced by the upstream activation of the epidermal growth factor receptor (EGFR, in human carcinoma epidermoide A431 cells, and by hydrogen peroxide-induced oxidative stress, in both A431 cells and human breast adenocarcinoma SK-BR-3 cells. Furthermore, we show that the Ca2+/CaM complex strongly activates the auto-phosphorylation and tyrosine kinase activity of c-Src toward exogenous substrates, but most relevantly and for the first time, we demonstrate that Ca2+-free CaM (apo-CaM exerts a far higher activatory action on Src auto-phosphorylation and kinase activity toward exogenous substrates than the one exerted by the Ca2+/CaM complex. This suggests that a transient increase in the cytosolic concentration of free Ca2+ is not an absolute requirement for CaM-mediated activation of Src in living cells, and that a direct regulation of Src by apo-CaM could be inferred.

  7. Glycine-extended gastrin activates two independent tyrosine-kinases in upstream of p85/p110 phosphatidylinositol 3-kinase in human colonic tumour cells

    Institute of Scientific and Technical Information of China (English)

    Audrey Ferrand; Aline Kowalski-Chauvel; Julie Pannequin; Claudine Bertrand; Daniel Fourmy; Marlene Dufresne; Catherine Seva

    2006-01-01

    AIM: To investigate whether Src, JAK2 and phosphatidylinositol 3-kinase (PI3K) pathways are involved in the proliferation of human colonic tumour cells induced by glycine-extended gastrin (G-gly), the precursor of the mature amidated gastrin and to elucidate the molecular interaction between these three kinases in response to this peptide.METHODS: Using the human colonic tumour cell line HCT116 as a model, we first measured the activation of PI3K, p60-Src and JAK2 in response to G-gly by in vitro kinase assays. Then we investigated the involvement of these kinases in G-gly-induced cell proliferation by MTT test.RESULTS: G-gly stimulation induced p60-Src, JAK2 and PI3K activation in HCT116. The different pathways were involved in proliferation of human colon cancer cells induced by G-gly. Furthermore, we found that both Src and JAK2 were necessary to PI3K regulation by this peptide. However, we did not find any cross-talk between the two tyrosine kinases.CONCLUSION: Our results suggest that the p60-Src/ PI3K and JAK2/PI3K pathways act independently to mediate G-gly proliferative effect on human colonic tumour cells.

  8. FGFR3, as a receptor tyrosine kinase, is associated with differentiated biological functions and improved survival of glioma patients.

    Science.gov (United States)

    Wang, Zheng; Zhang, Chuanbao; Sun, Lihua; Liang, Jingshan; Liu, Xing; Li, Guanzhang; Yao, Kun; Zhang, Wei; Jiang, Tao

    2016-12-20

    Activation of receptor tyrosine kinases is common in Malignancies. FGFR3 fusion with TACC3 has been reported to have transforming effects in primary glioblastoma and display oncogenic activity in vitro and in vivo. We set out to investigate the role of FGFR3 in glioma through transcriptomic analysis. FGFR3 increased in Classical subtype and Neural subtype consistently in CGGA and TCGA cohort. Similar patterns of FGFR3 distribution through subtypes were observed in CGGA and TCGA samples. Gene ontology analysis was performed with genes that were significantly correlated with FGFR3 expression. We found that positively associated biological processes of FGFR3 were focused on differentiated cellular functions and neuronal activities, while negatively correlated biological processes focused on mitosis and cell cycle phase. Clinical investigation showed that higher FGFR3 expression predicted improved survival for glioma patients, especially in Proneural subtype. Moreover, FGFR3 showed very limited relevance with other receptor tyrosine kinases in glioma at transcriptome level. FGFR3 expression data of glioma was obtained from Chinese Glioma Genome Atlas (CGGA) and TCGA (The Cancer Genome Atlas). In total, RNA sequencing data of 325 glioma samples and mRNA microarray data of 301 samples from CGGA dataset were enrolled into this study. To consolidate the findings that we have revealed in CGGA dataset, RNA-seq data of 672 glioma samples from TCGA dataset were used as a validation cohort. R language was used as the main tool to perform statistical analysis and graphical work. FGFR3 expression increased in classical and neural subtypes and was associated with differentiated cellular functions. FGFR3 showed very limited correlation with other common receptor tyrosine kinases, and predicted improved survival for glioma patients.

  9. HER2 Oncogenic Function Escapes EGFR Tyrosine Kinase Inhibitors via Activation of Alternative HER Receptors in Breast Cancer Cells

    Science.gov (United States)

    Kong, Anthony; Calleja, Véronique; Leboucher, Pierre; Harris, Adrian; Parker, Peter J.; Larijani, Banafshé

    2008-01-01

    Background The response rate to EGFR tyrosine kinase inhibitors (TKIs) may be poor and unpredictable in cancer patients with EGFR expression itself being an inadequate response indicator. There is limited understanding of the mechanisms underlying this resistance. Furthermore, although TKIs suppress the growth of HER2-overexpressing breast tumor cells, they do not fully inhibit HER2 oncogenic function at physiological doses. Methodology and Principal Findings Here we have provided a molecular mechanism of how HER2 oncogenic function escapes TKIs' inhibition via alternative HER receptor activation as a result of autocrine ligand release. Using both Förster Resonance Energy Transfer (FRET) which monitors in situ HER receptor phosphorylation as well as classical biochemical analysis, we have shown that the specific tyrosine kinase inhibitors (TKIs) of EGFR, AG1478 and Iressa (Gefitinib) decreased EGFR and HER3 phosphorylation through the inhibition of EGFR/HER3 dimerization. Consequent to this, we demonstrate that cleavage of HER4 and dimerization of HER4/HER2 occur together with reactivation of HER3 via HER2/HER3, leading to persistent HER2 phosphorylation in the now resistant, surviving cells. These drug treatment–induced processes were found to be mediated by the release of ligands including heregulin and betacellulin that activate HER3 and HER4 via HER2. Whereas an anti-betacellulin antibody in combination with Iressa increased the anti-proliferative effect in resistant cells, ligands such as heregulin and betacellulin rendered sensitive SKBR3 cells resistant to Iressa. Conclusions and Significance These results demonstrate the role of drug-induced autocrine events leading to the activation of alternative HER receptors in maintaining HER2 phosphorylation and in mediating resistance to EGFR tyrosine kinase inhibitors (TKIs) in breast cancer cells, and hence specify treatment opportunities to overcome resistance in patients. PMID:18682844

  10. Alteration and potential role of soluble fms-like tyrosine kinase receptor 1 in preeclampsia

    Institute of Scientific and Technical Information of China (English)

    LI Yi; LI Dong-hong; YAO Yuan-qing; ZHAO Hong-xi; ZHANG Chun-li; HUANG Liang

    2005-01-01

    Objective:To investigate the alteration of serum soluble fms-like tyrosine kinase receptor 1 (sFlt-1), the possible cause in preeclampsia, the relationship between altered sFlt-1 and the development of pregnancy. Methods: Semi-quantitative RT-PCR was carried out to detect the level of sFlt-1 mRNA in placental tissue of 10 preeclampsia (study group) and 10 normotensive pregnancies (control group); ELISA was used to detect the serum level of sFlt-1 in peripheral venous blood and uterine venous blood in control group (n=35) and study group (n=35), and furthermore to detect the volume of peripheral venous blood sFlt-1 in early, middle and later pregnancies. Results: sFlt-1 mRNA of placental tissue was significantly higher in preeclampsia than that in normal pregnancy. The serum level of sFlt-1 of peripheral vein in preeclampsia was higher than that in normal pregnancy ([ 5639.6±3190.5] pg/ml vs[ 2194.4±635.8 ] pg/ml, P<0.01) , so did the serum sFlt-1 of uterine vein in preeclampsia and control group ([7673.3±2295.8] pg/ml vs[ 3056.6±784.6] pg/ml, P<0.01), indicating that the volume of sFlt-1 of uterine vein blood was significantly higher than that of peripheral venous blood (P<0.01). The serum level of sFlt-1 in early, middle and later pregnancy were (31.7±19.6) pg/ml (n=10), (994.0±302.1) pg/ml (n=10), (2194.4±635.8) pg/ml (n=35), respectively, showing that the level of sFlt-1 in peripheral venous blood increasingly elevated with the development of pregnancy (P<0.01). Conclusion: Preeclampsia is associated with increased level of sFlt-1 which might be largely from placenta during pregnancy.

  11. The Met receptor tyrosine kinase prevents zebrafish primary motoneurons from expressing an incorrect neurotransmitter

    Directory of Open Access Journals (Sweden)

    Eisen Judith S

    2008-07-01

    Full Text Available Abstract Background Expression of correct neurotransmitters is crucial for normal nervous system function. How neurotransmitter expression is regulated is not well-understood; however, previous studies provide evidence that both environmental signals and intrinsic differentiation programs are involved. One environmental signal known to regulate neurotransmitter expression in vertebrate motoneurons is Hepatocyte growth factor, which acts through the Met receptor tyrosine kinase and also affects other aspects of motoneuron differentiation, including axonal extension. Here we test the role of Met in development of motoneurons in embryonic zebrafish. Results We found that met is expressed in all early developing, individually identified primary motoneurons and in at least some later developing secondary motoneurons. We used morpholino antisense oligonucleotides to knock down Met function and found that Met has distinct roles in primary and secondary motoneurons. Most secondary motoneurons were absent from met morpholino-injected embryos, suggesting that Met is required for their formation. We used chemical inhibitors to test several downstream pathways activated by Met and found that secondary motoneuron development may depend on the p38 and/or Akt pathways. In contrast, primary motoneurons were present in met morpholino-injected embryos. However, a significant fraction of them had truncated axons. Surprisingly, some CaPs in met morpholino antisense oligonucleotide (MO-injected embryos developed a hybrid morphology in which they had both a peripheral axon innervating muscle and an interneuron-like axon within the spinal cord. In addition, in met MO-injected embryos primary motoneurons co-expressed mRNA encoding Choline acetyltransferase, the synthetic enzyme for their normal neurotransmitter, acetylcholine, and mRNA encoding Glutamate decarboxylase 1, the synthetic enzyme for GABA, a neurotransmitter never normally found in these motoneurons, but

  12. Tyrosine kinase domain mutations of EGFR gene in head and neck squamous cell carcinoma

    Directory of Open Access Journals (Sweden)

    Vatte C

    2017-03-01

    Full Text Available Chittibabu Vatte,1 Ali M Al Amri,2 Cyril Cyrus,1 Shahanas Chathoth,1 Sadananda Acharya,3 Tariq Mohammad Hashim,4 Zhara Al Ali,2 Saleh Tawfeeq Alshreadah,2 Ahmed Alsayyah,4 Amein K Al-Ali5 1Department of Genetic Research, Institute for Research and Medical Consultation, University of Dammam, Dammam, 2Department of Internal Medicine, King Fahd Hospital of the University, University of Dammam, Al-Khobar, 3Department of Stemcell Research, Institute for Research and Medical Consultation, 4Department of Pathology, King Fahd Hospital of the University, University of Dammam, Al-Khobar, 5Department of Biochemistry, College of Medicine, University of Dammam, Dammam, Kingdom of Saudi Arabia Background: Epidermal growth factor receptor (EGFR is a commonly altered gene that is identified in various cancers, including head and neck squamous cell carcinoma (HNSCC. Therefore, EGFR is a promising molecular marker targeted by monoclonal antibodies and small molecule inhibitors targeting the tyrosine kinase (TK domain. Objective: The objective of this study was to investigate the spectrum of mutations in exons 18, 19, 20, and 21 of the EGFR gene in HNSCC patients. Materials and methods: This retrospective study included 47 confirmed HNSCC cases. Mutations in the TK domain, exons 18, 19, 20, and 21 of the EGFR gene, were detected by Scorpion® chemistry and ARMS® technologies on Rotor-Gene Q real-time polymerase chain reaction.Results: The tumors exhibited EGFR-TK domain mutations in 57% of cases. Four cases of T790M mutations were reported for the first time among HNSCC patients. Out of the total mutations, L861Q (exon 21, exon 20 insertions and deletions of exon 19 accounted for the majority of mutations (21%, 19%, and 17%, respectively. EGFR mutation status was correlated with the higher grade (P=0.026 and advanced stage (P=0.034 of HNSCC tumors.Conclusion: Higher frequency of EGFR-TK domain mutations together with the presence of the T790M mutation suggests

  13. A proof-of-concept study with the tyrosine kinase inhibitor nilotinib in spondyloarthritis.

    Science.gov (United States)

    Paramarta, Jacqueline E; Turina, Maureen C; Noordenbos, Troy; Heijda, Tanja F; Blijdorp, Iris C; Yeremenko, Nataliya; Baeten, Dominique

    2016-10-27

    To evaluate the immunomodulating and clinical effects of nilotinib, a tyrosine kinase inhibitor, in a proof-of-concept study in spondyloarthritis (SpA) assessing the mast cell as potential novel therapeutic target in this disease. Twenty eight patients with active peripheral (pSpA) and/or axial SpA (axSpA) were included in a randomized, double-blind, placebo-controlled clinical trial (Trial registration: Trialregister.nl NTR2834). Patients were treated 1:1 with nilotinib or placebo for 12 weeks, followed by an open label extension for another 12 weeks. Paired synovial tissue biopsies, serum sampling and assessment of clinical symptoms were performed serially. In pSpA (n = 13) synovial inflammation appeared to diminish after 12 weeks of nilotinib treatment as evidenced by histopathology (decrease in number of infiltrating CD68+ and CD163+ macrophages and mast cells). Compared to placebo mRNA expression of c-Kit as mast cell marker (p = 0.037) and of pro-inflammatory cytokines such as IL-6 (p = 0.024) were reduced. The reduction of synovial inflammation was paralleled by a decrease in serum biomarkers of inflammation such as C-reactive protein (p = 0.024) and calprotectin (p = 0.055). Also clinical parameters such as patient's global assessment of disease activity (p = 0.031) and ankylosing spondylitis disease activity score (p = 0.031) showed improvement upon 12 weeks of nilotinib but not placebo treatment. This improvement was further augmented at week 24. In contrast to pSpA, neither serum biomarkers of inflammation nor clinical parameters improved upon nilotinib treatment in axSpA. During the trial one serious adverse event occurred, which was considered unrelated to the study drug. This small proof-of-concept study suggests that nilotinib treatment modulates inflammation and clinical symptoms in pSpA. A similar effect was not seen in axSpA. trialregister.nl registration code NTR2834 registered 31 March 2011.

  14. N-linked glycosylation supports cross-talk between receptor tyrosine kinases and androgen receptor.

    Directory of Open Access Journals (Sweden)

    Harri M Itkonen

    Full Text Available Prostate cancer is the second most common cause of cancer-associated deaths in men and signalling via a transcription factor called androgen receptor (AR is an important driver of the disease. Androgen treatment is known to affect the expression and activity of other oncogenes including receptor tyrosine kinases (RTKs. In this study we report that AR-positive prostate cancer cell-lines express 50% higher levels of enzymes in the hexosamine biosynthesis pathway (HBP than AR-negative prostate cell-lines. HBP produces hexosamines that are used by endoplasmic reticulum and golgi enzymes to glycosylate proteins targeted to plasma-membrane and secretion. Inhibition of O-linked glycosylation by ST045849 or N-linked glycosylation with tunicamycin decreased cell viability by 20%. In addition, tunicamycin inhibited the androgen-induced expression of AR target genes KLK3 and CaMKK2 by 50%. RTKs have been shown to enhance AR activity and we used an antibody array to identify changes in the phosphorylation status of RTKs in response to androgen stimulation. Hormone treatment increased the activity of Insulin like Growth Factor 1-Receptor (IGF-1R ten-fold and this was associated with a concomitant increase in the N-linked glycosylation of the receptor, analyzed by lectin enrichment experiments. Glycosylation is known to be important for the processing and stability of RTKs. Inhibition of N-linked glycosylation resulted in accumulation of IGF-1R pro-receptor with altered mobility as shown by immunoprecipitation. Confocal imaging revealed that androgen induced plasma-membrane localization of IGF-1R was blocked by tunicamycin. In conclusion we have established that the glycosylation of IGF-1R is necessary for the full activation of the receptor in response to androgen treatment and that perturbing this process can break the feedback loop between AR and IGF-1R activation in prostate cells. Achieving similar results selectively in a clinical setting will be an

  15. The tricarboxylic acid cycle activity in cultured primary astrocytes is strongly accelerated by the protein tyrosine kinase inhibitor tyrphostin 23

    DEFF Research Database (Denmark)

    Hohnholt, Michaela C; Blumrich, Eva-Maria; Waagepetersen, Helle S

    2017-01-01

    production. In addition, T23-treatment strongly increased the molecular carbon labeling of the TCA cycle intermediates citrate, succinate, fumarate and malate, and significantly increased the incorporation of (13)C-labelling into the amino acids glutamate, glutamine and aspartate. These results clearly......Tyrphostin 23 (T23) is a well-known inhibitor of protein tyrosine kinases and has been considered as potential anti-cancer drug. T23 was recently reported to acutely stimulate the glycolytic flux in primary cultured astrocytes. To investigate whether T23 also affects the tricarboxylic acid (TCA...

  16. Primary cilia and coordination of receptor tyrosine kinase (RTK) and transforming growth factor β (TGF-β) signaling

    DEFF Research Database (Denmark)

    Christensen, Søren Tvorup; Morthorst, Stine Kjær; Mogensen, Johanne Bay

    2017-01-01

    in their extracellular environment and integrate and transmit signaling information to the cell to regulate various cellular, developmental, and physiological processes. Many different signaling pathways have now been shown to rely on primary cilia to function properly, and mutations that lead to ciliary dysfunction...... are at the root of a pleiotropic group of diseases and syndromic disorders called ciliopathies. In this review, we present an overview of primary cilia-mediated regulation of receptor tyrosine kinase (RTK) and transforming growth factor β (TGF-β) signaling. Further, we discuss how defects in the coordination...

  17. Molecular Basis of the Binding of YAP Transcriptional Regulator to the ErbB4 Receptor Tyrosine Kinase

    OpenAIRE

    Schuchardt, Brett J.; Bhat, Vikas; Mikles, David C.; McDonald, Caleb B.; Sudol, Marius; Farooq, Amjad

    2014-01-01

    The newly discovered transactivation function of ErbB4 receptor tyrosine kinase is believed to be mediated by virtue of the ability of its proteolytically-cleaved intracellular domain (ICD) to physically associate with YAP2 transcriptional regulator. In an effort to unearth the molecular basis of YAP2-ErbB4 interaction, we have conducted a detailed biophysical analysis of the binding of WW domains of YAP2 to PPXY motifs located within the ICD of ErbB4. Our data show that the WW1 domain of YAP...

  18. 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.

  19. Bruton's tyrosine kinase inhibitors and their clinical potential in the treatment of B-cell malignancies: focus on ibrutinib.

    Science.gov (United States)

    Aalipour, Amin; Advani, Ranjana H

    2014-08-01

    Aberrant signaling of the B-cell receptor pathway has been linked to the development and maintenance of B-cell malignancies. Bruton's tyrosine kinase (BTK), a protein early in this pathway, has emerged as a new therapeutic target in a variety of such malignancies. Ibrutinib, the most clinically advanced small molecule inhibitor of BTK, has demonstrated impressive tolerability and activity in a range of B-cell lymphomas which led to its recent approval for relapsed mantle cell lymphoma and chronic lymphocytic leukemia. This review focuses on the preclinical and clinical development of ibrutinib and discusses its therapeutic potential.

  20. Direct and two-step bioorthogonal probes for Bruton's tyrosine kinase based on ibrutinib: a comparative study.

    Science.gov (United States)

    Liu, Nora; Hoogendoorn, Sascha; van de Kar, Bas; Kaptein, Allard; Barf, Tjeerd; Driessen, Christoph; Filippov, Dmitri V; van der Marel, Gijsbert A; van der Stelt, Mario; Overkleeft, Herman S

    2015-05-14

    Ibrutinib is a covalent and irreversible inhibitor of Bruton's tyrosine kinase (BTK) and has been approved for the treatment of haematological malignancies, such as chronic lymphocytic leukaemia, mantle cell lymphoma and Waldenström's macroglobulinemia. The covalent and irreversible nature of its molecular mode of action allows identification and monitoring of its target in an activity-based protein profiling (ABPP) setting. Fluorescent and biotinylated ibrutinib derivatives have appeared in the literature in recent years to monitor BTK in vitro and in situ. The work described here complements this existing methodology and pertains a comparative study on the efficacy of direct and two-step bioorthogonal ABPP of BTK.

  1. [Tyrosine-protein kinase activity in breast neoplasm. Comparison with activity obtained in benign diseases and in normal tissues].

    Science.gov (United States)

    Pierart, J; Oñate, E; Klaassen, R; Cid, L; Gutierrez, S; Talbot, E; Ross, E; Zambrano, C; Burmeister, R; Puchi, M

    1995-02-01

    Tyrosine protein kinase (TPK) activity is associated to malignant cellular transformation. This work compares TPK activity in 27 surgical biopsy samples of mammary carcinoma, 10 samples of fibroadenomas, 13 samples of fibrocystic breast disease and 27 samples of normal mammary tissue. TPK activity was determined in tissue homogenates using (Val5) angiotensin II as exogenous substrate. In samples of mammary carcinoma, TPK activity was 33.86 +/- 31.98 pmol P32/mg protein/30 min. This value was significantly higher that those observed in fibrocystic disease (3.92 +/- 2.35), fibroadenomas (13.86 +/- 10.9) and normal tissue (3.56 +/- 3.02).

  2. Tyrosine kinase activity, cytoskeletal organization, and motility in human vascular endothelial cells.

    OpenAIRE

    1994-01-01

    Tyrosine phosphorylation of cytoskeletal proteins occurs during integrin-mediated cell adhesion to extracellular matrix proteins. We have investigated the role of tyrosine phosphorylation in the migration and initial spreading of human umbilical vein endothelial cells (HUVEC). Elevated phosphotyrosine concentrations were noted in the focal adhesions of HUVEC migrating into wounds. Anti-phosphotyrosine Western blots of extracts of wounded HUVEC monolayers demonstrated increased phosphorylation...

  3. Salmonella induces SRC protein tyrosine kinase, c-Jun N-terminal kinase (JNK), and NF-kappaBp65 signaling pathways in commercial and wild-type turkey leukocytes

    Science.gov (United States)

    Previous studies comparing signaling in wild-type turkey (WT) leukocytes and commercial turkey (CT) leukocytes found that the activity of protein tyrosine kinases and MAP kinases, ERK 1/2 and p38, were significantly higher in WT leukocytes compared to CT lines upon exposure to both SE and OPSE on d...

  4. CEP-701 and CEP-751 inhibit constitutively activated RET tyrosine kinase activity and block medullary thyroid carcinoma cell growth.

    Science.gov (United States)

    Strock, Christopher J; Park, Jong-In; Rosen, Mark; Dionne, Craig; Ruggeri, Bruce; Jones-Bolin, Susan; Denmeade, Samuel R; Ball, Douglas W; Nelkin, Barry D

    2003-09-01

    All of the cases of medullary thyroid carcinoma (MTC) express the RET receptor tyrosine kinase. In essentially all of the hereditary cases and approximately 40% of the sporadic cases of MTC, the RET kinase is constitutively activated by mutation. This suggests that RET may be an effective therapeutic target for treatment of MTC. We show that the indolocarbazole derivatives, CEP-701 and CEP-751, inhibit RET in MTC cells. These compounds effectively inhibit RET phosphorylation in a dose-dependent manner at concentrations <100 nM in 0.5% serum and at somewhat higher concentrations in the presence of 16% serum. They also blocked the growth of these MTC cells in culture. CEP-751 and its prodrug, CEP-2563, also inhibited tumor growth in MTC cell xenografts. These results show that inhibiting RET can block the growth of MTC cells and may have a therapeutic benefit in MTC.

  5. Third-Generation Tyrosine Kinase Inhibitors Targeting Epidermal Growth Factor Receptor Mutations in Non-Small Cell Lung Cancer

    Directory of Open Access Journals (Sweden)

    Tristan A. Barnes

    2017-05-01

    Full Text Available Sensitizing mutations in the epidermal growth factor receptor (EGFR predict response to EGFR tyrosine kinase inhibitors (TKIs and both first- and second-generation TKIs are available as first-line treatment options in patients with advanced EGFR-mutant non-small cell lung cancer. Eventual resistance develops with multiple mechanisms identifiable both upon repeat biopsy and in plasma circulating tumor DNA. The T790M gatekeeper mutation is responsible for almost 60% of cases. A number of third-generation TKIs are in clinical development, and osimertinib has been approved by the US Food and Drug Administration for the treatment of patients with EGFR T790M mutant lung cancer after failure of initial EGFR kinase therapy. Resistance mechanisms are being identified to these novel agents, and the treatment landscape of EGFR-mutant lung cancer continues to evolve. The sequence of EGFR TKIs may change in the future and combination therapies targeting resistance appear highly promising.

  6. Third-Generation Tyrosine Kinase Inhibitors Targeting Epidermal Growth Factor Receptor Mutations in Non-Small Cell Lung Cancer.

    Science.gov (United States)

    Barnes, Tristan A; O'Kane, Grainne M; Vincent, Mark David; Leighl, Natasha B

    2017-01-01

    Sensitizing mutations in the epidermal growth factor receptor (EGFR) predict response to EGFR tyrosine kinase inhibitors (TKIs) and both first- and second-generation TKIs are available as first-line treatment options in patients with advanced EGFR-mutant non-small cell lung cancer. Eventual resistance develops with multiple mechanisms identifiable both upon repeat biopsy and in plasma circulating tumor DNA. The T790M gatekeeper mutation is responsible for almost 60% of cases. A number of third-generation TKIs are in clinical development, and osimertinib has been approved by the US Food and Drug Administration for the treatment of patients with EGFR T790M mutant lung cancer after failure of initial EGFR kinase therapy. Resistance mechanisms are being identified to these novel agents, and the treatment landscape of EGFR-mutant lung cancer continues to evolve. The sequence of EGFR TKIs may change in the future and combination therapies targeting resistance appear highly promising.

  7. Oncogenic tyrosine kinase NPM/ALK induces activation of the rapamycin-sensitive mTOR signaling pathway.

    Science.gov (United States)

    Marzec, M; Kasprzycka, M; Liu, X; El-Salem, M; Halasa, K; Raghunath, P N; Bucki, R; Wlodarski, P; Wasik, M A

    2007-08-16

    The mechanisms of cell transformation mediated by the nucleophosmin (NPM)/anaplastic lymphoma kinase (ALK) tyrosine kinase are only partially understood. Here, we report that cell lines and native tissues derived from the NPM/ALK-expressing T-cell lymphoma display persistent activation of mammalian target of rapamycin (mTOR) as determined by phosphorylation of mTOR targets S6rp and 4E-binding protein 1 (4E-BP1). The mTOR activation is serum growth factor-independent but nutrient-dependent. It is also dependent on the expression and enzymatic activity of NPM/ALK as demonstrated by cell transfection with wild-type and functionally deficient NPM/ALK, small interfering RNA (siRNA)-mediated NPM/ALK depletion and kinase activity suppression using the inhibitor WHI-P154. The NPM/ALK-induced mTOR activation is transduced through the mitogen-induced extracellular kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathway and, to a much lesser degree, through the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway. Accordingly, whereas the low-dose PI3K inhibitor wortmannin and Akt inhibitor III profoundly inhibited Akt phosphorylation, they had a very modest effect on S6rp and 4E-BP1 phosphorylation. In turn, MEK inhibitors U0126 and PD98059 and siRNA-mediated depletion of either ERK1 or ERK2 inhibited S6rp phosphorylation much more effectively. Finally, the mTOR inhibitor rapamycin markedly decreased proliferation and increased the apoptotic rate of ALK+TCL cells. These findings identify mTOR as a novel key target of NPM/ALK and suggest that mTOR inhibitors may prove effective in therapy of ALK-induced malignancies.

  8. Regeneration of human epidermis on acellular dermis is impeded by small-molecule inhibitors of EGF receptor tyrosine kinase.

    Science.gov (United States)

    Forsberg, Sofi; Ostman, Arne; Rollman, Ola

    2008-10-01

    The family of human epidermal growth factor receptors (EGFR, HER2-4) exerts key functions in normal and malignant epithelial cells. Both EGFR and HER2 are valuable targets for anti-cancer drugs by interfering with ligand binding, receptor dimerization, or tyrosine kinase activity. A similar therapeutic strategy has been advocated for chronic psoriasis since plaque lesions overexpress EGFR and its ligands. Our aim was to characterize EGFR/HER2 protein expression in skin cultures and to evaluate the effects of tyrosine kinase inhibitors on epidermal outgrowth, morphology, and EGFR activation. Human skin explants were established on cell-free dermis and cultured at the air-liquid interface. The impact of small-molecule HER inhibitors on outgrowth was assayed by fluorescence-based image analysis and histometry. Effects of a dual EGFR/HER2 kinase inhibitor, PKI166, on neoepidermis were studied by immunohistochemistry and Western blot. Receptor immunostaining showed in vivo-like distributions with highest EGFR intensity in the proliferative layers whereas HER2 was mainly expressed by suprabasal keratinocytes. Reepithelialization was associated with EGFR autophosphorylation irrespective of exogenous ligand stimulation. PKI166 inhibited neoepidermal EGFR activation, keratinocyte proliferation, and outgrowth from normal and psoriatic skin explants. The rate of epidermalization in presence of other HER inhibitors varied suggesting that drug specificity, potency, and reversibility determine the dynamic outcome. Overall, agents predominantly targeting EGFR kinase were more efficient inhibitors of epidermal regeneration than an HER2-selective drug. The study illustrates the usefulness of a dynamic skin model and emphasizes the potential of HER-directed approaches to control epidermal growth in hyperproliferative skin disorders.

  9. 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.

  10. An in silico high-throughput screen identifies potential selective inhibitors for the non-receptor tyrosine kinase Pyk2

    Directory of Open Access Journals (Sweden)

    Meirson T

    2017-05-01

    Full Text Available Tomer Meirson, Abraham O Samson, Hava Gil-Henn Faculty of Medicine in the Galilee, Bar-Ilan University, Safed, Israel Abstract: The non-receptor tyrosine kinase proline-rich tyrosine kinase 2 (Pyk2 is a critical mediator of signaling from cell surface growth factor and adhesion receptors to cell migration, proliferation, and survival. Emerging evidence indicates that signaling by Pyk2 regulates hematopoietic cell response, bone density, neuronal degeneration, angiogenesis, and cancer. These physiological and pathological roles of Pyk2 warrant it as a valuable therapeutic target for invasive cancers, osteoporosis, Alzheimer’s disease, and inflammatory cellular response. Despite its potential as a therapeutic target, no potent and selective inhibitor of Pyk2 is available at present. As a first step toward discovering specific potential inhibitors of Pyk2, we used an in silico high-throughput screening approach. A virtual library of six million lead-like compounds was docked against four different high-resolution Pyk2 kinase domain crystal structures and further selected for predicted potency and ligand efficiency. Ligand selectivity for Pyk2 over focal adhesion kinase (FAK was evaluated by comparative docking of ligands and measurement of binding free energy so as to obtain 40 potential candidates. Finally, the structural flexibility of a subset of the docking complexes was evaluated by molecular dynamics simulation, followed by intermolecular interaction analysis. These compounds may be considered as promising leads for further development of highly selective Pyk2 inhibitors. Keywords: virtual screen, efficiency metrics, MM-GBSA, molecular dynamics

  11. Mice lacking protein tyrosine kinase fyn develop a T helper-type 1 response and resistLeishmania major infection.

    Science.gov (United States)

    Yamakami, K; Akao, S; Wakabayashi, K; Tadakuma, T; Yoshizawa, N

    2001-07-01

    Fyn is a Src family protein tyrosine kinase associated with TCR/CD3 complex. Fyn appears to play a role in the activation of T cells based on its enzymatic activation and tyrosine phosphorylation following the ligation of TCR/CD3, and it also plays a critical role in the calcium flux and interleukin-2 (IL-2) production. The protective response against murineLeishmania major infection is associated with the T helper-type 1 (Th1) responses and the ability to modulate Th1 cytokines such as IL-2 and interferon-γ, respectively. The role of Fyn tyrosine kinasein vivo was directly examined by the response to infection withL. major in C57BL/6fyn-deficient mice. Despite the absence of Fyn, the mice remained resistant to this infection with only mild lesion development, and, they demonstrated Th1 responses as assessed by the delayed-type hyper-sensitivity response and cytokine milieu. The findings in thefyn-deficient mice failed to support a relationship between the anticipated functions of Fynin vitro and the immune response toL. major infectionin vivo. As a result, in leishmanial disease, Fyn probably plays a minor role in the protective immune response and is, therefore, not a key factor in such a response.

  12. The 44 kDa Pim-1 kinase directly interacts with tyrosine kinase Etk/BMX and protects human prostate cancer cells from apoptosis induced by chemotherapeutic drugs.

    Science.gov (United States)

    Xie, Y; Xu, K; Dai, B; Guo, Z; Jiang, T; Chen, H; Qiu, Y

    2006-01-05

    Protein kinase Pim-1 has been implicated in the development of hematopoietic and prostatic malignancies. Here, we present the evidence that two isoforms, the 44 and 33 kDa Pim-1, are expressed in all human prostate cancer cell lines examined. The subcellular localization of human 44 kDa Pim-1 is primarily on the plasma membrane, while the 33 kDa isoform is present in both the cytosol and nucleus in PCA cells. The 44 kDa Pim-1 contains the proline-rich motif at the N-terminus and directly binds to the SH3 domain of tyrosine kinase Etk. Such interaction leads to the activation of Etk kinase activity possibly by competing with the tumor suppressor p53. This is corroborated by the fact that overexpression of the 44 kDa Pim-1 in prostate cancer cells confers the resistance to chemotherapeutic drugs. Our results suggest that these two isoforms of Pim-1 kinase may regulate distinct substrates and the 44 kDa Pim-1 may play a more prominent role in drug resistance in prostate cancer cells.

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

    Energy Technology Data Exchange (ETDEWEB)

    Park, So Jung; Park, Young Jun; Shin, Ji Hyun; Kim, Eun Sung [Graduate School of East-West Medical Science, Kyung Hee University, Gyeoggi-Do 446-701 (Korea, Republic of); Hwang, Jung Jin; Jin, Dong-Hoon; Kim, Jin Cheon [Institute for Innovative Cancer Research, Asan Medical Center, Seoul 138-736 (Korea, Republic of); Cho, Dong-Hyung, E-mail: dhcho@khu.ac.kr [Graduate School of East-West Medical Science, Kyung Hee University, Gyeoggi-Do 446-701 (Korea, Republic of)

    2011-05-13

    Highlights: {yields} We screened and identified Tyrphostin A9, a receptor tyrosine kinase inhibitor as a strong mitochondria fission inducer. {yields} Tyrphostin A9 treatment promotes mitochondria dysfunction and contributes to cytotoxicity in cancer cells. {yields} Tyrphostin A9 induces apoptotic cell death through a Drp1-mediated pathway. {yields} 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.

  14. BCR-ABL tyrosine kinase inhibitors in chronic myeloid leukemia: using guidelines to make rational treatment choices.

    Science.gov (United States)

    Kantarjian, Hagop; Cortes, Jorge

    2008-03-01

    The success of the BCR-ABL tyrosine kinase inhibitor (TKI) imatinib in improving prognosis in chronic myeloid leukemia (CML) has led to its wide use as first-line therapy at a standard dose of 400 mg daily. As more patients have undergone therapy, the development of molecular and clinical resistance to imatinib has raised further therapeutic challenges. The 2 main approaches to overcoming resistance are imatinib dose escalation and the use of alternative more potent TKIs, such as dasatinib or nilotinib. The phase II SRC/ABL Tyrosine Kinase Inhibition Activity Research Trials (START) of dasatinib have established dasatinib as potent and effective in overcoming imatinib resistance or intolerance in all phases of CML. The most recent treatment guidelines by the National Comprehensive Cancer Network now contain recommendations for using dasatinib in this setting. The issue of when to change from imatinib to an alternative agent in preference to imatinib dose escalation is keenly debated, particularly as new clinical evidence emerges, which highlights the importance of achieving early cytogenetic and molecular responses for a good long-term outcome. Identifying patients in whom a change to dasatinib or nilotinib is more appropriate than imatinib dose escalation is therefore important.

  15. A positive feedback loop between Gli1 and tyrosine kinase Hck amplifies shh signaling activities in medulloblastoma.

    Science.gov (United States)

    Shi, X; Zhan, X; Wu, J

    2015-11-30

    Sonic hedgehog (Shh) signaling is critical during normal development, and the abnormal activation of the Shh pathway is involved in many human cancers. As a target gene of the Shh pathway and as a transcription activator downstream of Shh signaling, Gli1 autoregulates and increases Shh signaling output. Gli1 is one of the key oncogenic factors in Shh-induced tumors such as medulloblastoma. Gli1 is posttranslationally modified, but the nature of the active form of Gli1 was unclear. Here we identified a Src family kinase Hck as a novel activator of Gli1. In Shh-responsive NIH3T3 cells, Hck interacts with Gli1 and phosphorylates multiple tyrosine residues in Gli1. Gli1-mediated target gene activation was significantly enhanced by Hck with both kinase activity-dependent and -independent mechanisms. We provide evidence showing that Hck disrupts the interaction between Gli1 and its inhibitor Sufu. In both NIH3T3 cells and cerebellum granule neuron precursors, the Hck gene is also a direct target of Gli1. Therefore, Gli1 and Hck form a positive feedback loop that amplifies Shh signaling transcription outcomes. In Shh-induced medulloblastoma, Hck is highly expressed and Gli1 is tyrosine phosphorylated, which may enhance the tumorigenic effects of the Gli1 oncogene. RNAi-mediated inhibition of Hck expression significantly repressed medulloblastoma cell growth. In summary, a novel positive feedback loop contributes to maximal Gli1 oncogenic activities in Shh-induced tumors such as medulloblastoma.

  16. Trichothecene mycotoxins activate NLRP3 inflammasome through a P2X7 receptor and Src tyrosine kinase dependent pathway.

    Science.gov (United States)

    Kankkunen, Päivi; Välimäki, Elina; Rintahaka, Johanna; Palomäki, Jaana; Nyman, Tuula; Alenius, Harri; Wolff, Henrik; Matikainen, Sampsa

    2014-02-01

    Inflammasome is an intracellular molecular platform of the innate immunity that is a key mediator of inflammation. The inflammasome complex detects pathogens and different danger signals, and triggers cysteine protease caspase-1-dependent processing of pro-inflammatory cytokines IL-1β, and IL-18 in dendritic cells and macrophages. Previously, we have shown that water-damaged building associated trichothecene mycotoxins, including roridin A, trigger IL-1β and IL-18 secretion in human macrophages. However, the molecular basis as well as mechanism behind this trichothecene-induced cytokine secretion has remained uncharacterized. Here, we show that the trichothecene-induced IL-1β secretion is dependent on NLRP3 inflammasome in human primary macrophages. Pharmacological inhibition and small interfering RNA approach showed that the trichothecene-induced NLRP3 inflammasome activation is mediated through ATP-gated P2X7 receptor. Moreover, we show that trichothecene-triggered NLRP3 inflammasome activation is dependent on Src tyrosine kinase activity. In addition, gene silencing of c-Cbl, a negative autophagy-related regulator of c-Src, resulted in enhanced secretion of IL-1β and IL-18 in response to trichothecene mycotoxin stimulation in human macrophages. In conclusion, our results suggest that roridin A, a fungal trichothecene mycotoxin, acts as microbial danger signals that trigger activation of NLRP3 inflammasome through P2X7R and Src tyrosine kinase signaling dependent pathway in human primary macrophages.

  17. The Molecular Crosstalk between the MET Receptor Tyrosine Kinase and the DNA Damage Response — Biological and Clinical Aspects

    Energy Technology Data Exchange (ETDEWEB)

    Medová, Michaela, E-mail: michaela.medova@dkf.unibe.ch; Aebersold, Daniel M.; Zimmer, Yitzhak, E-mail: michaela.medova@dkf.unibe.ch [Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, 3010 Bern (Switzerland); Department of Clinical Research, University of Bern, DKF, MEM-E807, Murtenstrasse 35, 3010 Bern (Switzerland)

    2013-12-19

    Radiation therapy remains an imperative treatment modality for numerous malignancies. Enduring significant technical achievements both on the levels of treatment planning and radiation delivery have led to improvements in local control of tumor growth and reduction in healthy tissue toxicity. Nevertheless, resistance mechanisms, which presumably also involve activation of DNA damage response signaling pathways that eventually may account for loco-regional relapse and consequent tumor progression, still remain a critical problem. Accumulating data suggest that signaling via growth factor receptor tyrosine kinases, which are aberrantly expressed in many tumors, may interfere with the cytotoxic impact of ionizing radiation via the direct activation of the DNA damage response, leading eventually to so-called tumor radioresistance. The aim of this review is to overview the current known data that support a molecular crosstalk between the hepatocyte growth factor receptor tyrosine kinase MET and the DNA damage response. Apart of extending well established concepts over MET biology beyond its function as a growth factor receptor, these observations directly relate to the role of its aberrant activity in resistance to DNA damaging agents, such as ionizing radiation, which are routinely used in cancer therapy and advocate tumor sensitization towards DNA damaging agents in combination with MET targeting.

  18. Bruton's tyrosine kinase (Btk) is a useful marker for Hodgkin and B cell non-Hodgkin lymphoma.

    Science.gov (United States)

    Fernández-Vega, Iván; Quirós, Luis M; Santos-Juanes, Jorge; Pane-Foix, María; Marafioti, Teresa

    2015-02-01

    Bruton's tyrosine kinase (Btk) is a member of the Tec family of protein tyrosine kinases involved in B cell development and proliferation in neoplastic human lymphoid tissues. We used immunohistochemistry to evaluate a polyclonal anti-Btk antibody on formalin-fixed paraffin-embedded tissue blocks. The tested samples included normal lymphoid tissues, tissue samples of 395 different lymphomas and 14 malignant lymphoid cell lines. Btk was expressed more often in B cell lymphomas than in T cell lymphomas. This correlated well with the results obtained on B cell lymphoma cell lines, which strongly expressed Btk, in contrast to T cell lymphoma cell lines. More than 60% of myelomas expressed Btk. Among Hodgkin lymphomas, the nodular lymphocyte predominant variant was more often positive (14/16) than the classical variant (6/27). Only one out of three Hodgkin lymphoma-derived cell lines showed a few atypical large cells expressing Btk. Btk represents a useful marker to identify B cell non-Hodgkin lymphomas. Furthermore, Btk might help to distinguish the nodular lymphocyte predominant variant of Hodgkin lymphomas from the classical form. Finally, in view of the recently discovered therapeutic potential of Btk inhibitors in lymphoma, we report the pattern of expression of Btk in a large collection of different types of lymphoma.

  19. Defective Toll-like receptor 9-mediated cytokine production in B cells from Bruton's tyrosine kinase-deficient mice

    Science.gov (United States)

    Hasan, Maroof; Lopez-Herrera, Gabriela; Blomberg, K Emelie M; Lindvall, Jessica M; Berglöf, Anna; Smith, C I Edvard; Vargas, Leonardo

    2008-01-01

    Bruton's tyrosine kinase (Btk), a member of the Tec family of tyrosine kinases, plays an important role in the differentiation and activation of B cells. Mutations affecting Btk cause immunodeficiency in both humans and mice. In this study we set out to investigate the potential role of Btk in Toll-like receptor 9 (TLR9) activation and the production of pro-inflammatory cytokines such as interleukin (IL)-6, tumour necrosis factor (TNF)-α and IL-12p40. Our data show that Btk-deficient B cells respond more efficiently to CpG-DNA stimulation, producing significantly higher levels of pro-inflammatory cytokines but lower levels of the inhibitory cytokine IL-10. The quantitative reverse transcription–polymerase chain reaction (RT-PCR) analysis presented in this work shows that mRNA production of one of the important new members of the IL-12 family, IL-27, was significantly increased in Btk-deficient B cells after CpG-DNA stimulation. In this study, we demonstrate significant differences in CpG responsiveness between transitional 1 (T1) and T2 B cells for survival and maturation. Furthermore, TLR9 expression, measured both as protein and as mRNA, was increased in Btk-defective cells, especially after TLR9 stimulation. Collectively, these data provide evidence in support of the theory that Btk regulates both TLR9 activation and expression in mouse splenic B cells. PMID:17725607

  20. Bmx, a member of the Tec family of nonreceptor tyrosine kinases, is a novel participant in pharmacological cardioprotection.

    Science.gov (United States)

    Zhang, Jun; Ping, Peipei; Wang, Guang-Wu; Lu, Ming; Pantaleon, Dawn; Tang, Xian-Liang; Bolli, Roberto; Vondriska, Thomas M

    2004-11-01

    Previous studies have indicated that PKC-epsilon is a central regulator of protective signal transduction in the heart. However, the signaling modules through which PKC-epsilon exerts its protective effects have only begun to be understood. We have identified a novel participant in the PKC-epsilon signaling system in cardioprotection, the nonreceptor tyrosine kinase Bmx. Functional proteomic analyses of PKC-epsilon signaling complexes identified Bmx as a member of these complexes. Subsequent studies in rabbits have indicated that Bmx is activated by nitric oxide (NO) in the heart, concomitant with the late phase of NO donor-induced protection, and provide the first analysis of Bmx expression/distribution in the setting of cardioprotection. In addition, increased expression of Bmx induced by NO donors was blocked by the same mechanism that blocked cardioprotection: inhibition of PKC with chelerythrine. These findings indicate that a novel type of PKC-tyrosine kinase module (involving Bmx) is formed in the heart and may be involved in pharmacological cardioprotection by NO donors.

  1. Coexpression of receptor-tyrosine-kinases in gastric adenocarcinoma-a rationale for a molecular targeting strategy?

    Institute of Scientific and Technical Information of China (English)

    Daniel Drescher; Thomas Wehler; Andreas Teufel; Kerstin Herzer; Thomas Fischer; Martin R Berger; Theodor Junginger; Peter R Galle; Carl C Schimanski; Markus Moehler; Ines Gockel; Kirsten Frerichs; Annett Müller; Friedrich Dünschede; Thomas Borschitz; Stefan Biesterfeld; Martin Holtmann

    2007-01-01

    AIM: To define the (co-)expression pattern of target receptor-tyrosine-kinases (RTK) in human gastric adenocarcinoma.METHODS: The (co-)expression pattern of VEGFR1-3,PDGFRα/β and EGFR1 was analyzed by RT-PCR in 51 human gastric adenocarcinomas. In addition, IHC staining was applied for confirmation of expression and analysis of RTK Iocalisation.RESULTS: The majority of samples revealed a VEGFR1(98%), VEGFR2 (80%), VEGFR3 (67%), PDGFRα(82%) and PDGFRβ (82%) expression, whereas only 62% exhibited an EGFR1 expression. 78% of cancers expressed at least four out of six RTKs. While VEGFR1-3and PDGFRα revealed a predominantly cytoplasmatic staining in tumor cells, accompanied by an additional nuclear staining for VEGFR3, EGFR1 was almost exclusively detected on the membrane of tumor cells.PDGFRβ was restricted to stromal pericytes, which also depicted a PDGFRα expression.CONCLUSION: Our results reveal a high rate of receptor-tyrosine-kinases coexpression in gastric adenocarcinoma and might therefore encourage an application of multiple-target RTK-inhibitors within a combination therapy.

  2. Lyn tyrosine kinase promotes silencing of ATM-dependent checkpoint signaling during recovery from DNA double-strand breaks

    Energy Technology Data Exchange (ETDEWEB)

    Fukumoto, Yasunori, E-mail: fukumoto@faculty.chiba-u.jp; Kuki, Kazumasa; Morii, Mariko; Miura, Takahito; Honda, Takuya; Ishibashi, Kenichi; Hasegawa, Hitomi; Kubota, Sho; Ide, Yudai; Yamaguchi, Noritaka; Nakayama, Yuji; Yamaguchi, Naoto, E-mail: nyama@faculty.chiba-u.jp

    2014-09-26

    Highlights: • Inhibition of Src family kinases decreased γ-H2AX signal. • Inhibition of Src family increased ATM-dependent phosphorylation of Chk2 and Kap1. • shRNA-mediated knockdown of Lyn increased phosphorylation of Kap1 by ATM. • Ectopic expression of Src family kinase suppressed ATM-mediated Kap1 phosphorylation. • Src is involved in upstream signaling for inactivation of ATM signaling. - Abstract: DNA damage activates the DNA damage checkpoint and the DNA repair machinery. After initial activation of DNA damage responses, cells recover to their original states through completion of DNA repair and termination of checkpoint signaling. Currently, little is known about the process by which cells recover from the DNA damage checkpoint, a process called checkpoint recovery. Here, we show that Src family kinases promote inactivation of ataxia telangiectasia mutated (ATM)-dependent checkpoint signaling during recovery from DNA double-strand breaks. Inhibition of Src activity increased ATM-dependent phosphorylation of Chk2 and Kap1. Src inhibition increased ATM signaling both in G2 phase and during asynchronous growth. shRNA knockdown of Lyn increased ATM signaling. Src-dependent nuclear tyrosine phosphorylation suppressed ATM-mediated Kap1 phosphorylation. These results suggest that Src family kinases are involved in upstream signaling that leads to inactivation of the ATM-dependent DNA damage checkpoint.

  3. Protein tyrosine kinases p53/56lyn and p72syk in MHC class I-mediated signal transduction in B lymphoma cells

    DEFF Research Database (Denmark)

    Pedersen, Anders Elm; Bregenholt, S; Skov, S

    1998-01-01

    Crosslinking of major histocompatibility complex class I (MHC-I) molecules on the surface of human B lymphoma cells was shown to induce protein tyrosine phosphorylation and mobilization of intracellular free calcium. Immunoprecipitations indicated that the protein tyrosine kinases p53/56lyn and p72...... and the results indicate that these two kinases have different substrate specificity and regulate intracellular free calcium differently in response to MHC-I crosslinking. In addition MHC-I crosslinking of a sIgM-negative DT40 chicken B cell variant results in less activity of tyrosine kinases and less...... mobilization of intracellular free calcium compared with MHC-I crosslinking of wild-type DT40 cells. Thus, expression of BCR at the cell surface is likely to be important for the signal cascade initiated by MHC-I crosslinking. Our data suggest that signal transduction initiated through ligation of the MHC...

  4. Inhaled tyrosine kinase inhibitors for pulmonary hypertension: a possible future treatment

    Directory of Open Access Journals (Sweden)

    Pitsiou G

    2014-10-01

    Full Text Available Georgia Pitsiou,1 Paul Zarogoulidis,1 Dimitris Petridis,2 Ioannis Kioumis,1 Sofia Lampaki,1 John Organtzis,1 Konstantinos Porpodis,1 Antonis Papaiwannou,1 Theodora Tsiouda,3 Wolfgang Hohenforst-Schmidt,4 Stylianos Kakolyris,5 Konstantinos Syrigos,6 Haidong Huang,7 Qiang Li,7 J Francis Turner,8 Konstantinos Zarogoulidis1 1Pulmonary Department, G Papanikolaou General Hospital, Aristotle University of Thessaloniki, 2Department of Food Technology, School of Food Technology and Nutrition, Alexander Technological Educational Institute, 3Internal Medicine Department, Thegenio Anticancer Hospital, Thessaloniki, Greece; 4II Medical Department, Coburg Regional Hospital, Coburg, Germany; 5Oncology Department, Sotiria Hospital of Chest Diseases, University of Athens, Athens, 6Oncology Department, University General Hospital of Alexandroupolis, Democritus University of Thrace, Alexandroupolis, Greece; 7Department of Respiratory Diseases, Changhai Hospital/First Affiliated Hospital of the Second Military Medical University, Shanghai, People’s Republic of China; 8Division of Interventional Pulmonology and Medical Oncology, Cancer Treatment Centers of America, Western Regional Medical Center, Goodyear, AZ, USA Abstract: Pulmonary hypertension is a disease with severe consequences for the human body. There are several diseases and situations that induce pulmonary hypertension and are usually underdiagnosed. Treatments include conventional medical therapies and oral, inhaled, intravenous, and subcutaneous options. Depending on its severity, heart or lung transplant may also be an option. A possible novel treatment could be tyrosine kinase inhibitors. We conducted experiments with three jet nebulizers and three ultrasound nebulizers with erlotinib, gefitinib, and imatinib. Different residual cup designs and residual cup loadings were used in order to identify the best combination to produce droplets of less than 5 µm in mass median aerodynamic diameter. We

  5. Mitotic aberrations induced by carbaryl reflect tyrosine kinase inhibition with coincident up-regulation of serine/threonine protein phosphatase activity: implications for coordination of karyokinesis and cytokinesis.

    Science.gov (United States)

    Renglin, A; Härmälä-Brasken, A S; Eriksson, J E; Onfelt, A

    1999-05-01

    The insecticide carbaryl and its metabolite 1-naphthol cause partial uncoupling of karyokinesis and cytokinesis in V79 Chinese hamster fibroblasts; karyokinesis is blocked in metaphase, the microtubules of the spindle depolymerize and the chromosomes and spindle remnants become displaced to the periphery of the cell. A high frequency of these disturbed cells elongate and a smaller fraction initiate a cleavage furrow. Here, we attempt to determine the potential targets for carbaryl and 1-naphthol in cytokinesis-specific signalling, led by the fact that the potential protein phosphatase inhibitor 1-naphthyl phosphate was previously identified in treated cells. We found that the typical cytological pattern induced by carbaryl and 1-naphthol could be obtained with tyrphostins, specific tyrosine kinase inhibitors, indicating that the carbaryl-induced effects could be due to tyrosine kinase inhibition. This was confirmed by tyrosine kinase assays showing that carbaryl, 1-naphthol and 2-naphthol were equally efficient at inhibiting tyrosine kinase activity as tyrphostin B44(-). As tyrosine kinases can act as regulatory factors in determining dephosphorylation rates, the activities of type-1 (PP1) and type-2A (PP2A) serine/threonine protein phosphatases were also determined. There was a clear up-regulation of the overall PP1/PP2A activities in cells treated with carbaryl, 1-naphthol or tyrphostin B44(-). This stimulation was shown to be indirect because these compounds had no effect on the activity of purified human PP1 in the test tube. 2-Naphthol, which has been found to be less efficient with regard to displacement of chromatin, did not cause up-regulation, but a significant decrease in PP1/PP2A activity. We suggest that a net decrease in tyrosine kinase activity in combination with a net increase in PP1/PP2A activity is a precondition for cell elongation and cytokinesis in mammalian cells and that the corresponding enzymes are targets in the network of activities

  6. Tyrosine kinase inhibitors improve long-term outcome of allogeneic hematopoietic stem cell transplantation for adult patients with Philadelphia chromosome positive acute lymphoblastic leukemia

    Science.gov (United States)

    Brissot, Eolia; Labopin, Myriam; Beckers, Marielle M.; Socié, Gérard; Rambaldi, Alessandro; Volin, Liisa; Finke, Jürgen; Lenhoff, Stig; Kröger, Nicolaus; Ossenkoppele, Gert J.; Craddock, Charles F.; Yakoub-Agha, Ibrahim; Gürman, Günhan; Russell, Nigel H.; Aljurf, Mahmoud; Potter, Michael N.; Nagler, Armon; Ottmann, Oliver; Cornelissen, Jan J.; Esteve, Jordi; Mohty, Mohamad

    2015-01-01

    This study aimed to determine the impact of tyrosine kinase inhibitors given pre- and post-allogeneic stem cell transplantation on long-term outcome of patients allografted for Philadelphia chromosome-positive acute lymphoblastic leukemia. This retrospective analysis from the EBMT Acute Leukemia Working Party included 473 de novo Philadelphia chromosome-positive acute lymphoblastic leukemia patients in first complete remission who underwent an allogeneic stem cell transplantation using a human leukocyte antigen-identical sibling or human leukocyte antigen-matched unrelated donor between 2000 and 2010. Three hundred and ninety patients received tyrosine kinase inhibitors before transplant, 329 at induction and 274 at consolidation. Kaplan-Meier estimates of leukemia-free survival, overall survival, cumulative incidences of relapse incidence, and non-relapse mortality at five years were 38%, 46%, 36% and 26%, respectively. In multivariate analysis, tyrosine-kinase inhibitors given before allogeneic stem cell transplantation was associated with a better overall survival (HR=0.68; P=0.04) and was associated with lower relapse incidence (HR=0.5; P=0.01). In the post-transplant period, multivariate analysis identified prophylactic tyrosine-kinase inhibitor administration to be a significant factor for improved leukemia-free survival (HR=0.44; P=0.002) and overall survival (HR=0.42; P=0.004), and a lower relapse incidence (HR=0.40; P=0.01). Over the past decade, administration of tyrosine kinase inhibitors before allogeneic stem cell transplantation has significantly improved the long-term allogeneic stem cell transplantation outcome of adult Philadelphia chromosome-positive acute lymphoblastic leukemia. Prospective studies will be of great interest to further confirm the potential benefit of the prophylactic use of tyrosine kinase inhibitors in the post-transplant setting. PMID:25527562

  7. rse, a novel receptor-type tyrosine kinase with homology to Axl/Ufo, is expressed at high levels in the brain.

    Science.gov (United States)

    Mark, M R; Scadden, D T; Wang, Z; Gu, Q; Goddard, A; Godowski, P J

    1994-04-08

    We have isolated cDNA clones that encode the human and murine forms of a novel receptor-type tyrosine kinase termed Rse. Sequence analysis indicates that human Rse contains 890 amino acids, with an extracellular region composed of two immunoglobulin-like domains followed by two fibronectin type III domains. Murine Rse contains 880 amino acids and shares 90% amino acid identity with its human counterpart. Rse is structurally similar to the receptor-type tyrosine kinase Axl/Ufo, and the two proteins have 35 and 63% sequence identity in their extracellular and intracellular domains, respectively. To study the synthesis and activation of this putative receptor-type tyrosine kinase, we constructed a version of Rse (termed gD-Rse, where gD represents glycoprotein D) that contains an NH2-terminal epitope tag. NIH3T3 cells were engineered to express gD-Rse, which could be detected at the cell surface by fluorescence-activated cell sorting. Moreover, gD-Rse was rapidly phosphorylated on tyrosine residues upon incubation of the cells with an antibody directed against the epitope tag, suggesting that rse encodes an active tyrosine kinase. In the human tissues we examined, the highest level of expression of rse mRNA was observed in the brain; rse mRNA was also detected in the premegakaryocytopoietic cell lines CMK11-5 and Dami. The gene for rse was localized to human chromosome 15.

  8. ABL tyrosine kinase inhibition variable effects on the invasive properties of different triple negative breast cancer cell lines.

    Directory of Open Access Journals (Sweden)

    Clément Chevalier

    Full Text Available The non-receptor tyrosine kinase ABL drives myeloid progenitor expansion in human chronic myeloid leukemia. ABL inhibition by the tyrosine kinase inhibitor nilotinib is a first-line treatment for this disease. Recently, ABL has also been implicated in the transforming properties of solid tumors, including triple negative (TN breast cancer. TN breast cancers are highly metastatic and several cell lines derived from these tumors display high invasive activity in vitro. This feature is associated with the activation of actin-rich membrane structures called invadopodia that promote extracellular matrix degradation. Here, we investigated nilotinib effect on the invasive and migratory properties of different TN breast cancer cell lines. Nilotinib decreased both matrix degradation and invasion in the TN breast cancer cell lines MDA-MB 231 and MDA-MB 468. However, and unexpectedly, nilotinib increased by two-fold the invasive properties of the TN breast cancer cell line BT-549 and of Src-transformed fibroblasts. Both display much higher levels of ABL kinase activity compared to MDA-MB 231. Similar effects were obtained by siRNA-mediated down-regulation of ABL expression, confirming ABL central role in this process. ABL anti-tumor effect in BT-549 cells and Src-transformed fibroblasts was not dependent on EGF secretion, as recently reported in neck and squamous carcinoma cells. Rather, we identified the TRIO-RAC1 axis as an important downstream element of ABL activity in these cancer cells. In conclusion, the observation that TN breast cancer cell lines respond differently to ABL inhibitors could have implications for future therapies.

  9. ABT-869, a multitargeted receptor tyrosine kinase inhibitor: inhibition of FLT3 phosphorylation and signaling in acute myeloid leukemia.

    Science.gov (United States)

    Shankar, Deepa B; Li, Junling; Tapang, Paul; Owen McCall, J; Pease, Lori J; Dai, Yujia; Wei, Ru-Qi; Albert, Daniel H; Bouska, Jennifer J; Osterling, Donald J; Guo, Jun; Marcotte, Patrick A; Johnson, Eric F; Soni, Niru; Hartandi, Kresna; Michaelides, Michael R; Davidsen, Steven K; Priceman, Saul J; Chang, Jenny C; Rhodes, Katrin; Shah, Neil; Moore, Theodore B; Sakamoto, Kathleen M; Glaser, Keith B

    2007-04-15

    In 15% to 30% of patients with acute myeloid leukemia (AML), aberrant proliferation is a consequence of a juxtamembrane mutation in the FLT3 gene (FMS-like tyrosine kinase 3-internal tandem duplication [FLT3-ITD]), causing constitutive kinase activity. ABT-869 (a multitargeted receptor tyrosine kinase inhibitor) inhibited the phosphorylation of FLT3, STAT5, and ERK, as well as Pim-1 expression in MV-4-11 and MOLM-13 cells (IC(50) approximately 1-10 nM) harboring the FLT3-ITD. ABT-869 inhibited the proliferation of these cells (IC(50) = 4 and 6 nM, respectively) through the induction of apoptosis (increased sub-G(0)/G(1) phase, caspase activation, and PARP cleavage), whereas cells harboring wild-type (wt)-FLT3 were less sensitive. In normal human blood spiked with AML cells, ABT-869 inhibited phosphorylation of FLT3 (IC(50) approximately 100 nM), STAT5, and ERK, and decreased Pim-1 expression. In methylcellulose-based colony-forming assays, ABT-869 had no significant effect up to 1000 nM on normal hematopoietic progenitor cells, whereas in AML patient samples harboring both FLT3-ITD and wt-FLT3, ABT-869 inhibited colony formation (IC(50) = 100 and 1000 nM, respectively). ABT-869 dose-dependently inhibited MV-4-11 and MOLM-13 flank tumor growth, prevented tumor formation, regressed established MV-4-11 xenografts, and increased survival by 20 weeks in an MV-4-11 engraftment model. In tumors, ABT-869 inhibited FLT3 phosphorylation, induced apoptosis (transferase-mediated dUTP nick-end labeling [TUNEL]) and decreased proliferation (Ki67). ABT-869 is under clinical development for AML.

  10. Os inibidores de tirosino quinase de segunda geração The inhibitors of tyrosine kinase

    Directory of Open Access Journals (Sweden)

    Márcia T. Delamain

    2008-04-01

    Full Text Available O imatinibe tem sido confirmado como terapia de primeira linha para a Leucemia Mielóide Crônica (LMC por apresentar respostas duradouras na maior parte dos pacientes, principalmente nos que se encontram em fase precoce da doença. Entretanto, resistência ou intolerância ao imatinibe podem ocorrer. A resistência ao imatinibe ocorre com muito mais freqüência em fases mais avançadas da doença, sendo a causa mais comum o desenvolvimento de mutações no sítio BCR-ABL. Em face deste problema, novos inibidores de tirosino quinase têm sido desenvolvidos, com maior potência, diminuindo assim a chance de desenvolvimento de resistência ao tratamento. O nilotinibe e o dasatinibe são dois exemplos de inibidores de segunda geração de tirosino quinase recentemente aprovados. Ambos têm demonstrado excelentes resultados em pacientes que desenvolvem resistência ou são intolerantes ao imatinibe.Despite the success with imatinib as the first choice treatment of chronic myeloid leukemia (CML, there is still a subset of patients that do not respond optimally to or are intolerant of this drug or lose response. Imatinib resistance can occur at any phase, but it is more frequent in advanced phases, with mutations in the BCR-ABL kinase domain being the most common mechanism of resistance. More potent tyrosine kinase inhibitors have been developed that can overcome resistance to imatinib. Nilotinib and dasatinib are good examples of new tyrosine kinase inhibitors that are available. With these new agents, patients who develop imatinib resistance or those unable to tolerate imatinib treatment can achieve significant clinical responses.

  11. Structural Characterization of Proline-rich Tyrosine Kinase 2 (PYK2) Reveals a Unique (DFG-out) Conformation and Enables Inhibitor Design

    Energy Technology Data Exchange (ETDEWEB)

    Han, Seungil; Mistry, Anil; Chang, Jeanne S.; Cunningham, David; Griffor, Matt; Bonnette, Peter C.; Wang, Hong; Chrunyk, Boris A.; Aspnes, Gary E.; Walker, Daniel P.; Brosius, Arthur D.; Buckbinder, Leonard; Pfizer

    2009-05-21

    Proline-rich tyrosine kinase 2 (PYK2) is a cytoplasmic, non-receptor tyrosine kinase implicated in multiple signaling pathways. It is a negative regulator of osteogenesis and considered a viable drug target for osteoporosis treatment. The high-resolution structures of the human PYK2 kinase domain with different inhibitor complexes establish the conventional bilobal kinase architecture and show the conformational variability of the DFG loop. The basis for the lack of selectivity for the classical kinase inhibitor, PF-431396, within the FAK family is explained by our structural analyses. Importantly, the novel DFG-out conformation with two diarylurea inhibitors (BIRB796, PF-4618433) reveals a distinct subclass of non-receptor tyrosine kinases identifiable by the gatekeeper Met-502 and the unique hinge loop conformation of Leu-504. This is the first example of a leucine residue in the hinge loop that blocks the ATP binding site in the DFG-out conformation. Our structural, biophysical, and pharmacological studies suggest that the unique features of the DFG motif, including Leu-504 hinge-loop variability, can be exploited for the development of selective protein kinase inhibitors.

  12. Identification of AKN-032, a novel 2-aminopyrazine tyrosine kinase inhibitor, with significant preclinical activity in acute myeloid leukemia.

    Science.gov (United States)

    Eriksson, Anna; Höglund, Martin; Lindhagen, Elin; Aleskog, Anna; Hassan, Sadia Bashir; Ekholm, Carina; Fhölenhag, Karin; Jensen, Annika Jenmalm; Löthgren, Agneta; Scobie, Martin; Larsson, Rolf; Parrow, Vendela

    2010-11-15

    Aberrant signal transduction by mutant or overexpressed protein kinases has emerged as a promising target for treatment of acute myeloid leukemia (AML). We here present a novel low molecular weight kinase inhibitor, AKN-032, targeting the FMS-like tyrosine kinase 3 (FLT3) and discovered in a new type of screening funnel combining the target therapy approach with sequential cellular screens. AKN-032 was identified among 150 selected hits from three different high throughput kinase screens. Further characterization showed inhibitory activity on FLT3 enzyme with an IC(50) of 70 nM. Western blot analysis revealed reduced autophosphorylation of the FLT3-receptor in AML cell line MV4-11 cells after exposure to AKN-032. Flow cytometry disclosed cytotoxic activity against MV4-11, but not against non-malignant 3T3-L1 fibroblast cells. Using a fluorometric microculture cytotoxicity assay, AKN-032 was tested against 15 cell lines and displayed a potent cytotoxic activity in AML cell lines MV4-11 (IC(50)=0.4 μM) and Kasumi-1 (IC(50)=2.3 μM). AKN-032 was also highly cytotoxic in tumor cells from AML patients in vitro. Furthermore, AKN-032 demonstrated significant antileukemic effect in a relatively resistant in vivo hollow fiber mouse model. No major toxicity was observed in the animals. In conclusion, AKN-032 is a promising new kinase inhibitor with significant in vivo and in vitro activity in AML. Results from the hollow fiber mouse assay suggest a favorable toxicity profile. Future studies will focus on pharmacokinetic properties, toxicity as well as further clarifying the mechanisms of action of AKN-032 in AML.

  13. Activation of extracellular signal-regulated kinase during silibinin-protected, isoproterenol-induced apoptosis in rat cardiac myocytes is tyrosine kinase pathway-mediated and protein kinase C-dependent

    Institute of Scientific and Technical Information of China (English)

    Bei ZHOU; Li-jun WU; Shin-ichi TASHIRO; Satoshi ONODERA; Fumiaki UCHIUMI; Takashi IKEJIMA

    2007-01-01

    Aim: To investigate the mechanism of silibinin-protected isoproterenol-induced apoptosis in rat cardiac myocytes.Methods: The viability of rat cardiac myocytes was measured by MTT method. The apoptotic ratio was measured by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling. Protein kinase C (PKC) activity assay was carried out according to the instructions of the PepTag non-radioactive protein kinase C assay kit. Western blot analysis was used to evaluate the level of Ras, Raf-1 and mitogen-activated protein kinase (MAPK) expression.Results: The protective effects of silibinin were significantly sup-pressed by inhibitors, including genistein, manumycin A and GW5074 [inhibitors for protein tyrosine kinases (PTK), Ras and Raf- 1, respectively]. The exposure of rat cardiac myocytes to isoproterenol alone caused decreased PKC activity, which was prevented by pretreatment with silibinin dose-dependently. Simultaneously,the increased expression of Ras and Raf-1 activated by silibinin were blocked by the PKC inhibitor, stauroporine. In addition, the extracellularly responsive kinase (ERK) inhibitor, PD98059, suppressed silibinin-protected apoptosis, whereas the p38 MAPK inhibitor, SB203580, protected cardiac myocytes from isoproterenol-induced injury, and the c-Jun N-terminal kinase (JNK) inhibitor, SP600125 had no protective effects. Furthermore, Western blot analysis showed that the expres-sion of phosphorylated ERK was increased by silibinin, the expression of phos-phorylated p38 MAPK was decreased and total ERK, p38, JNK and phosphory-lated JNK MAPK did not change after treatment with both isoproterenol and silibinin. Furthermore, pretreatment of cardiac myocyte with PKC, Ras and Raf inhibitors significantly blocked ERK phosphorylation.Conclusion: Silibinin is suggested to protect isoproterenol-induced rat cardiac myocyte apoptosis by activating the tyrosine kinase pathway, PKC and MAPK pathways.

  14. Bisubstrate analog probes for the insulin receptor protein tyrosine kinase: molecular yardsticks for analyzing catalytic mechanism and inhibitor design.

    Science.gov (United States)

    Hines, Aliya C; Parang, Keykavous; Kohanski, Ronald A; Hubbard, Stevan R; Cole, Philip A

    2005-08-01

    Bisubstrate analogs have the potential to provide enhanced specificity for protein kinase inhibition and tools to understand catalytic mechanism. Previous efforts led to the design of a peptide-ATP conjugate bisubstrate analog utilizing aminophenylalanine in place of tyrosine and a thioacetyl linker to the gamma-phosphate of ATP which was a potent inhibitor of the insulin receptor kinase (IRK). In this study, we have examined the contributions of various electrostatic and structural elements in the bisubstrate analog to IRK binding affinity. Three types of changes (seven specific analogs in all) were introduced: a Tyr isostere of the previous aminophenylalanine moiety, modifications of the spacer between the adenine and the peptide, and deletions and substitutions within the peptide moiety. These studies allowed a direct evaluation of the hydrogen bond strength between the anilino nitrogen of the bisubstrate analog and the enzyme catalytic base Asp and showed that it contributes 2.5 kcal/mol of binding energy, in good agreement with previous predictions. Modifications of the linker length resulted in weakened inhibitory affinity, consistent with the geometric requirements of an enzyme-catalyzed dissociative transition state. Alterations in the peptide motif generally led to diminished inhibitory potency, and only some of these effects could be rationalized based on prior kinetic and structural studies. Taken together, these results suggest that a combination of mechanism-based design and empirical synthetic manipulation will be necessary in producing optimized protein kinase bisubstrate analog inhibitors.

  15. Lipid raft localization of EGFR alters the response of cancer cells to the EGFR tyrosine kinase inhibitor gefitinib.

    Science.gov (United States)

    Irwin, Mary E; Mueller, Kelly L; Bohin, Natacha; Ge, Yubin; Boerner, Julie L

    2011-09-01

    Epidermal growth factor receptor (EGFR) is overexpressed in many cancer types including ~30% of breast cancers. Several small molecule tyrosine kinase inhibitors (TKIs) targeting EGFR have shown clinical efficacy in lung and colon cancers, but no benefit has been noted in breast cancer. Thirteen EGFR expressing breast cancer cell lines were analyzed for response to EGFR TKIs. Seven were found to be EGFR TKI resistant; while shRNA knockdown of EGFR determined that four of these cell lines retained the requirement of EGFR protein expression for growth. Interestingly, EGFR localized to plasma membrane lipid rafts in all four of these EGFR TKI-resistant cell lines, as determined by biochemical raft isolation and immunofluorescence. When lipid rafts were depleted of cholesterol using lovastatin, all four cell lines were sensitized to EGFR TKIs. In fact, the effects of the cholesterol biosynthesis inhibitors and gefitinib were synergistic. While gefitinib effectively abrogated phosphorylation of Akt- and mitogen-activated protein kinase in an EGFR TKI-sensitive cell line, phosphorylation of Akt persisted in two EGFR TKI-resistant cell lines, however, this phosphorylation was abrogated by lovastatin treatment. Thus, we have shown that lipid raft localization of EGFR correlates with resistance to EGFR TKI-induced growth inhibition and pharmacological depletion of cholesterol from lipid rafts decreases this resistance in breast cancer cell lines. Furthermore, we have presented evidence to suggest that when EGFR localizes to lipid rafts, these rafts provide a platform to facilitate activation of Akt signaling in the absence of EGFR kinase activity.

  16. The NPM-ALK tyrosine kinase mimics TCR signalling pathways, inducing NFAT and AP-1 by RAS-dependent mechanisms.

    Science.gov (United States)

    Turner, Suzanne D; Yeung, Debra; Hadfield, Kathryn; Cook, Simon J; Alexander, Denis R

    2007-04-01

    Nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) expression is associated with the lymphoid malignancy anaplastic large cell lymphoma (ALCL) and results from a t(2;5) chromosomal translocation. We show that NPM-ALK induces Ras activation and phosphorylation of the ERK MAP Kinase consistent with activation of the Ras-MAP Kinase pathway. Furthermore, we demonstrate that activation of Ras is necessary for inducing transcription via NFAT/AP-1 composite transcriptional binding sites. This activity is dependent on NPM-ALK forming complexes with proteins that bind to autophosphorylated tyrosine residues at positions 156, 567 and 664, associated with binding to IRS-1, Shc and PLCgamma, respectively. Specifically, NPM-ALK activates transcription from the TRE promoter element, an AP-1 binding region, an activity dependent on both Ras and Shc activity. Our results show that NPM-ALK mimics activated T-cell receptor signalling by inducing pathways associated with the activation of NFAT/AP-1 transcription factors that bind to promoter elements found in a broad array of cytokine genes.

  17. A "liaison dangereuse" between AUF1/hnRNPD and the oncogenic tyrosine kinase NPM-ALK.

    Science.gov (United States)

    Fawal, Mohamad; Armstrong, Florence; Ollier, Severine; Dupont, Henri; Touriol, Christian; Monsarrat, Bernard; Delsol, Georges; Payrastre, Bernard; Morello, Dominique

    2006-10-15

    Nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) is a chimeric protein expressed in a subset of cases of anaplastic large cell lymphoma (ALCL) for which constitutive expression represents a key oncogenic event. The ALK signaling pathway is complex and probably involves functional redundancy between various signaling substrates of ALK. Despite numerous studies on signaling mediators, the molecular mechanisms contributing to the distinct oncogenic features of NPM-ALK remain incompletely understood. The search for additional interacting partners of NPM-ALK led to the discovery of AUF1/hnRNPD, a protein implicated in AU-rich element (ARE)-directed mRNA decay. AUF1 was immunoprecipitated with ALK both in ALCL-derived cells and in NIH3T3 cells stably expressing NPM-ALK or other X-ALK fusion proteins. AUF1 and NPM-ALK were found concentrated in the same cytoplasmic foci, whose formation required NPM-ALK tyrosine kinase activity. AUF1 was phosphorylated by ALK in vitro and was hyperphosphorylated in NPM-ALK-expressing cells. Its hyperphosphorylation was correlated with increased stability of several AUF1 target mRNAs encoding key regulators of cell proliferation and with increased cell survival after transcriptional arrest. Thus, AUF1 could function in a novel pathway mediating the oncogenic effects of NPM-ALK. Our data establish an important link between oncogenic kinases and mRNA turnover, which could constitute a critical aspect of tumorigenesis.

  18. Large, detergent-resistant complexes containing murine antigens Thy-1 and Ly-6 and protein tyrosine kinase p56lck.

    Science.gov (United States)

    Bohuslav, J; Cinek, T; Horejsí, V

    1993-04-01

    A number of human and mouse leukocyte surface (glyco)proteins anchored in a membrane via glycosylphosphatidylinositol (GPI) moiety have been previously shown to be noncovalently associated with protein tyrosine kinases (Science 1991. 254: 1016; J. Biol. Chem. 1992. 267: 12317). Here we show that two murine antigens of this group, Thy-1 and Ly-6, implicated in the activation of the T cells, are associated with each other, with the kinase p56lck and with several of potential kinase substrates in very large, detergent-resistant complexes, the size of which is between 50 and 200 nm, as determined by ultrafiltration and gel chromatography. Experiments on simultaneous solubilization of mixed human and mouse cells rule out that the observed complexes are artifacts induced by the detergent. Complexes of similar composition and properties were obtained when either detergents Brij-58, Nonidet-P40 or 3-[(3-cholamidopropyl)-dimethylammonio]- 1-propane-sulfonate (Chaps) were used for solubilization of the cells, while octylglucoside at least partially dissociated them. These "GPI-complexes" may be essential for the well-known signal-transducing capacity of Thy-1 and Ly-6.

  19. Bi-directional regulation between tyrosine kinase Etk/BMX and tumor suppressor p53 in response to DNA damage.

    Science.gov (United States)

    Jiang, Tianyun; Guo, Zhiyong; Dai, Bojie; Kang, Miyoung; Ann, David K; Kung, Hsing-Jien; Qiu, Yun

    2004-11-26

    Etk/Bmx, a member of the Tec family of nonreceptor tyrosine kinases, has been implicated in the regulation of various cellular processes including proliferation, differentiation, motility, and apoptosis. Here, we report the identification of Tec family kinases as the potential interacting proteins of the tumor suppressor p53 by an Src homology 3 domain array screening. Etk is physically associated with p53 through its Src homology 3 domain and the proline-rich domain of p53. Induction of p53 expression by DNA damage inhibits Etk activity in several cell types. Down-regulation of Etk expression by a specific small interfering RNA sensitizes prostate cancer cells to doxorubicin-induced apoptosis, suggesting that inhibition of Etk activity is required for apoptosis in response to DNA damage. We also show that Etk primarily interacts with p53 in the cytoplasm and that such interaction leads to bidirectional inhibition of the activities of both proteins. Overexpression of Etk in prostate cancer cells results in inhibition of p53 transcriptional activity and its interaction with the mitochondrial protein BAK and confers the resistance to doxorubicin. Therefore, we propose that the stoichiometry between p53 and the Tec family kinases in a given cell type may determine its sensitivity to chemotherapeutic drugs.

  20. Specific oncogenic activity of the Src-family tyrosine kinase c-Yes in colon carcinoma cells.

    Science.gov (United States)

    Sancier, Florence; Dumont, Aurélie; Sirvent, Audrey; Paquay de Plater, Ludmilla; Edmonds, Thomas; David, Géraldine; Jan, Michel; de Montrion, Catherine; Cogé, Francis; Léonce, Stéphane; Burbridge, Michael; Bruno, Alain; Boutin, Jean A; Lockhart, Brian; Roche, Serge; Cruzalegui, Francisco

    2011-02-24

    c-Yes, a member of the Src tyrosine kinase family, is found highly activated in colon carcinoma but its importance relative to c-Src has remained unclear. Here we show that, in HT29 colon carcinoma cells, silencing of c-Yes, but not of c-Src, selectively leads to an increase of cell clustering associated with a localisation of β-catenin at cell membranes and a reduction of expression of β-catenin target genes. c-Yes silencing induced an increase in apoptosis, inhibition of growth in soft-agar and in mouse xenografts, inhibition of cell migration and loss of the capacity to generate liver metastases in mice. Re-introduction of c-Yes, but not c -Src, restores transforming properties of c-Yes depleted cells. Moreover, we found that c-Yes kinase activity is required for its role in β-catenin localisation and growth in soft agar, whereas kinase activity is dispensable for its role in cell migration. We conclude that c-Yes regulates specific oncogenic signalling pathways important for colon cancer progression that is not shared with c-Src.

  1. Patients harboring EGFR mutation after primary resistance to crizotinib and response to EGFR-tyrosine kinase inhibitor

    Directory of Open Access Journals (Sweden)

    Wang WX

    2016-01-01

    Full Text Available Wenxian Wang,1 Xiaowen Jiang,1 Zhengbo Song,1,2 Yiping Zhang1,2 1Department of Chemotherapy, Zhejiang Cancer Hospital, 2Key Laboratory Diagnosis and Treatment Technology on Thoracic Oncology, Hangzhou, Zhejiang, People’s Republic of China Abstract: Anaplastic lymphoma kinase (ALK rearrangement lung cancer responds to ALK tyrosine kinase inhibitors. It is known that many cases ultimately acquired resistance to crizotinib. However, a case of primary resistance is rare. We present a case of harboring exon 19 deletion in epidermal growth factor receptor in ALK rearranged lung adenocarcinoma, who experienced a partial tumor response to icotinib after failure with crizotinib therapy and chemotherapy. Considering the partial response, we conclude that it is important to find the cause of resistance to crizotinib. We detected gene mutations with plasma by the next-generation sequencing; the next-generation sequencing demonstrates an attractive system to identify mutations improving the outcome of patients with a deadly disease. Keywords: non-small cell lung cancer, anaplastic lymphoma kinase, crizotinib, epidermal growth factor receptor

  2. A fully automated two-step synthesis of an {sup 18}F-labelled tyrosine kinase inhibitor for EGFR kinase activity imaging in tumors

    Energy Technology Data Exchange (ETDEWEB)

    Kobus, D.; Giesen, Y.; Ullrich, R.; Backes, H. [Max Planck Institute for Neurological Research with Klaus-Joachim-Zuelch Laboratories of the Max Planck Society and the Faculty of Medicine of the University of Cologne, Cologne (Germany); Neumaier, B. [Max Planck Institute for Neurological Research with Klaus-Joachim-Zuelch Laboratories of the Max Planck Society and the Faculty of Medicine of the University of Cologne, Cologne (Germany)], E-mail: bernd.neumaier@nf.mpg.de

    2009-11-15

    Radiolabelled epidermal growth factor receptor (EGFR) tyrosine kinase (TK) inhibitors potentially facilitate the assessment of EGFR overexpression in tumors. Since elaborate multi-step radiosyntheses are required for {sup 18}F-labelling of EGFR-specific anilinoquinazolines we report on the development of a two-step click labelling approach that was adapted to a fully automated synthesis module. 6-(4-N,N-Dimethylaminocrotonyl)amido-4-(3-chloro-4-fluoro)phenylamino-7-{l_brace}3- [4-(2-[{sup 18}F]fluoroethyl)-2,3,4-triazol-1-yl]propoxy{r_brace}quinazoline ([{sup 18}F]6) was synthesized via Huisgen 1,3-dipolar cycloaddition between 2-[{sup 18}F]fluoroethylazide ([{sup 18}F]4) and the alkyne modified anilinoquinazoline precursor 5. PET images of PC9 tumor xenograft using the novel biomarker showed promising results to visualize EGFR overexpression.

  3. Bmx tyrosine kinase regulates TLR4-induced IL-6 production in human macrophages independently of p38 MAPK and NFkapp}B activity.

    Science.gov (United States)

    Palmer, Christine D; Mutch, Brenda E; Workman, Sarita; McDaid, John P; Horwood, Nicole J; Foxwell, Brian M J

    2008-02-15

    Chronic inflammation, as seen in conditions such as rheumatoid arthritis and Crohn disease, is in part driven by discordant production of inflammatory cytokines, such as tumor necrosis factor-alpha and interleukin-6 (IL-6). Tyrosine kinase activity is essential to lipopolysaccharide-induced cytokine production in monocytes, and previous studies by us and others have implicated a role for the Tec kinase Bruton's tyrosine kinase (Btk) in inflammatory cytokine production. Here we show that knockdown of Btk using RNA interference results in decreased tumor necrosis factor-alpha, but not IL-6 production. Further investigations into the signaling mechanisms regulating IL-6 production led to the discovery that the Tec kinase bone marrow tyrosine kinase gene in chromosome X (Bmx) regulates Toll-like receptor-induced IL-6 production. Our data further showed that Bmx-dependent super-induction of IL-6 does not involve nuclear factor-kappaB activity. More detailed investigations of pathways downstream of Bmx signaling revealed that Bmx targets the IL-6 3' untranslated region to increase mRNA stabilization via a novel, thus far undefined, p38 mitogen activated protein kinase-independent pathway. These data have important implications for the design of therapeutics targeted against specific cytokines and their regulators in inflammatory disease.

  4. Prevention of pulmonary vascular and myocardial remodeling by the combined tyrosine and serine-/threonine kinase inhibitor, sorafenib, in pulmonary hypertension and right heart failure

    Directory of Open Access Journals (Sweden)

    M. Klein

    2008-06-01

    Full Text Available Inhibition of tyrosine kinases can reverse pulmonary hypertension but little is known about the role of serine-/threonine kinases in vascular and myocardial remodeling. We investigated the effects of sorafenib, an inhibitor of the tyrosine kinases VEGFR, PDGFR and c-kit as well as the serine-/threonine kinase Raf-1, in pulmonary hypertension and right ventricular (RV pressure overload. In monocrotaline treated rats, sorafenib (10 mg·kg–1·d–1 p.o. reduced pulmonary arterial pressure, pulmonary artery muscularization and RV hypertrophy, and improved systemic hemodynamics (table 1. Sorafenib prevented phosphorylation of Raf-1 and suppressed activation of downstream signaling pathways (Erk 1/2. After pulmonary banding, sorafenib, but not the PDGFR/c-KIT/ABL-inhibitor imatinib reduced RV mass and RV filling pressure significantly. Congruent with these results, sorafenib only prevented ERK phosphorylation and vasopressin induced hypertrophy of the cardiomyocyte cell line H9c2 dose dependently (IC50 = 300 nM. Combined inhibition of tyrosine and serine-/threonine kinases by sorafenib prevents vascular and cardiac remodeling in pulmonary hypertension, which is partly mediated via inhibition of the Raf kinase pathway.

  5. Neuropeptide-induced androgen independence in prostate cancer cells: roles of nonreceptor tyrosine kinases Etk/Bmx, Src, and focal adhesion kinase.

    Science.gov (United States)

    Lee, L F; Guan, J; Qiu, Y; Kung, H J

    2001-12-01

    The bombesin/gastrin-releasing peptide (GRP) family of neuropeptides has been implicated in various in vitro and in vivo models of human malignancies including prostate cancers. It was previously shown that bombesin and/or neurotensin (NT) acts as a survival and migratory factor(s) for androgen-independent prostate cancers. However, a role in the transition from an androgen-dependent to -refractory state has not been addressed. In this study, we investigate the biological effects and signal pathways of bombesin and NT on LNCaP, a prostate cancer cell line which requires androgen for growth. We show that both neurotrophic factors can induce LNCaP growth in the absence of androgen. Concurrent transactivation of reporter genes driven by the prostate-specific antigen promoter or a promoter carrying an androgen-responsive element (ARE) indicate that growth stimulation is accompanied by androgen receptor (AR) activation. Furthermore, neurotrophic factor-induced gene activation was also present in PC3 cells transfected with the AR but not in the parental line which lacks the AR. Given that bombesin does not directly bind to the AR and is known to engage a G-protein-coupled receptor, we investigated downstream signaling events that could possibly interact with the AR pathway. We found that three nonreceptor tyrosine kinases, focal adhesion kinase (FAK), Src, and Etk/BMX play important parts in this process. Etk/Bmx activation requires FAK and Src and is critical for neurotrophic factor-induced growth, as LNCaP cells transfected with a dominant-negative Etk/BMX fail to respond to bombesin. Etk's activation requires FAK, Src, but not phosphatidylinositol 3-kinase. Likewise, bombesin-induced AR activation is inhibited by the dominant-negative mutant of either Src or FAK. Thus, in addition to defining a new G-protein pathway, this report makes the following points regarding prostate cancer. (i) Neurotrophic factors can activate the AR, thus circumventing the normal growth

  6. Nitration of Tyrosine 247 Inhibits Protein Kinase G-1α Activity by Attenuating Cyclic Guanosine Monophosphate Binding*

    Science.gov (United States)

    Aggarwal, Saurabh; Gross, Christine M.; Rafikov, Ruslan; Kumar, Sanjiv; Fineman, Jeffrey R.; Ludewig, Britta; Jonigk, Danny; Black, Stephen M.

    2014-01-01

    The cGMP-dependent protein kinase G-1α (PKG-1α) is a downstream mediator of nitric oxide and natriuretic peptide signaling. Alterations in this pathway play a key role in the pathogenesis and progression of vascular diseases associated with increased vascular tone and thickness, such as pulmonary hypertension. Previous studies have shown that tyrosine nitration attenuates PKG-1α activity. However, little is known about the mechanisms involved in this event. Utilizing mass spectrometry, we found that PKG-1α is susceptible to nitration at tyrosine 247 and 425. Tyrosine to phenylalanine mutants, Y247F- and Y425F-PKG-1α, were both less susceptible to nitration than WT PKG-1α, but only Y247F-PKG-1α exhibited preserved activity, suggesting that the nitration of Tyr247 is critical in attenuating PKG-1α activity. The overexpression of WT- or Y247F-PKG-1α decreased the proliferation of pulmonary artery smooth muscle cells (SMC), increased the expression of SMC contractile markers, and decreased the expression of proliferative markers. Nitrosative stress induced a switch from a contractile to a synthetic phenotype in cells expressing WT- but not Y247F-PKG-1α. An antibody generated against 3-NT-Y247 identified increased levels of nitrated PKG-1α in humans with pulmonary hypertension. Finally, to gain a more mechanistic understanding of how nitration attenuates PKG activity, we developed a homology model of PKG-1α. This model predicted that the nitration of Tyr247 would decrease the affinity of PKG-1α for cGMP, which we confirmed using a [3H]cGMP binding assay. Our study shows that the nitration of Tyr247 and the attenuation of cGMP binding is an important mechanism regulating in PKG-1α activity and SMC proliferation/differentiation. PMID:24469460

  7. Nitration of tyrosine 247 inhibits protein kinase G-1α activity by attenuating cyclic guanosine monophosphate binding.

    Science.gov (United States)

    Aggarwal, Saurabh; Gross, Christine M; Rafikov, Ruslan; Kumar, Sanjiv; Fineman, Jeffrey R; Ludewig, Britta; Jonigk, Danny; Black, Stephen M

    2014-03-14

    The cGMP-dependent protein kinase G-1α (PKG-1α) is a downstream mediator of nitric oxide and natriuretic peptide signaling. Alterations in this pathway play a key role in the pathogenesis and progression of vascular diseases associated with increased vascular tone and thickness, such as pulmonary hypertension. Previous studies have shown that tyrosine nitration attenuates PKG-1α activity. However, little is known about the mechanisms involved in this event. Utilizing mass spectrometry, we found that PKG-1α is susceptible to nitration at tyrosine 247 and 425. Tyrosine to phenylalanine mutants, Y247F- and Y425F-PKG-1α, were both less susceptible to nitration than WT PKG-1α, but only Y247F-PKG-1α exhibited preserved activity, suggesting that the nitration of Tyr(247) is critical in attenuating PKG-1α activity. The overexpression of WT- or Y247F-PKG-1α decreased the proliferation of pulmonary artery smooth muscle cells (SMC), increased the expression of SMC contractile markers, and decreased the expression of proliferative markers. Nitrosative stress induced a switch from a contractile to a synthetic phenotype in cells expressing WT- but not Y247F-PKG-1α. An antibody generated against 3-NT-Y247 identified increased levels of nitrated PKG-1α in humans with pulmonary hypertension. Finally, to gain a more mechanistic understanding of how nitration attenuates PKG activity, we developed a homology model of PKG-1α. This model predicted that the nitration of Tyr(247) would decrease the affinity of PKG-1α for cGMP, which we confirmed using a [(3)H]cGMP binding assay. Our study shows that the nitration of Tyr(247) and the attenuation of cGMP binding is an important mechanism regulating in PKG-1α activity and SMC proliferation/differentiation.

  8. Anti-VEGF strategies - from antibodies to tyrosine kinase inhibitors: background and clinical development in human cancer.

    LENUS (Irish Health Repository)

    Korpanty, Grzegorz

    2012-01-01

    Tumour angiogenesis (formation of new blood vessels supporting tumour growth and metastasis) is a result of complex interactions between the tumour and the surrounding microenvironment. Targeting tumours with anti-angiogenic therapy remains an exciting area of preclinical and clinical studies. Although many significant advances have been achieved and the clinical use of anti-angiogenic drugs is now well recognized in many solid malignancies, these therapies fall short of their anticipated clinical benefits and leave many unanswered questions like exact mechanism of action, patients\\' selection and monitoring response to anti-angiogenic drugs. Tumour angiogenesis is controlled by complex signaling cascades and ongoing research into molecular mechanisms of tumour angiogenesis not only helps to understand its basic mechanisms but hopefully will identify new therapeutic targets. In 2012, both monoclonal antibodies and small molecule tyrosine kinase inhibitors remain the two major clinically useful therapeutic options that interfere with tumour angiogenesis in many solid malignancies.

  9. Repositioning of Tyrosine Kinase Inhibitors as Antagonists of ATP-Binding Cassette Transporters in Anticancer Drug Resistance

    Directory of Open Access Journals (Sweden)

    Yi-Jun Wang

    2014-09-01

    Full Text Available The phenomenon of multidrug resistance (MDR has attenuated the efficacy of anticancer drugs and the possibility of successful cancer chemotherapy. ATP-binding cassette (ABC transporters play an essential role in mediating MDR in cancer cells by increasing efflux of drugs from cancer cells, hence reducing the intracellular accumulation of chemotherapeutic drugs. Interestingly, small-molecule tyrosine kinase inhibitors (TKIs, such as AST1306, lapatinib, linsitinib, masitinib, motesanib, nilotinib, telatinib and WHI-P154, have been found to have the capability to overcome anticancer drug resistance by inhibiting ABC transporters in recent years. This review will focus on some of the latest and clinical developments with ABC transporters, TKIs and anticancer drug resistance.

  10. Antidepressant drug exposure is associated with mRNA levels of tyrosine receptor kinase B in major depressive disorder.

    Science.gov (United States)

    Bayer, T A; Schramm, M; Feldmann, N; Knable, M B; Falkai, P

    2000-08-01

    1. Recent studies have provided support for the notion that the high affinity neurotrophin receptor tyrosine receptor kinase B (trk B) may be involved in the treatment of depression. 2. Using a quantitative RT-PCR approach trk B mRNA levels were determined in brain material from cerebellum, temporal cortex, and frontal cortex of control specimen and patients with major depressive disorder, schizophrenia and bipolar disorder (15 subjects each). 3. Interestingly, elevated trk B mRNA levels were found in cerebellum (3.6-fold) in patients with major depressive disorder, reaching statistical significance (p=0.03). 4. The major depressive disorder-on drugs group differed from controls (p=0.006) in the cerebellum. 5. Since only patients with major depressive disorder received antidepressants, elevated trk B mRNA levels are possibly related to drug treatment.

  11. Deorphanization of the human leukocyte tyrosine kinase (LTK) receptor by a signaling screen of the extracellular proteome

    Science.gov (United States)

    Zhang, Hongbing; Pao, Lily I.; Zhou, Aileen; Brace, Arthur D.; Halenbeck, Robert; Hsu, Amy W.; Bray, Thomas L.; Hestir, Kevin; Bosch, Elizabeth; Lee, Ernestine; Wang, Gang; Liu, Haixia; Wong, Brian R.; Kavanaugh, W. Michael; Williams, Lewis T.

    2014-01-01

    There are many transmembrane receptor-like proteins whose ligands have not been identified. A strategy for finding ligands when little is known about their tissue source is to screen each extracellular protein individually expressed in an array format by using a sensitive functional readout. Taking this approach, we have screened a large collection (3,191 proteins) of extracellular proteins for their ability to activate signaling of an orphan receptor, leukocyte tyrosine kinase (LTK). Only two related secreted factors, FAM150A and FAM150B (family with sequence similarity 150 member A and member B), stimulated LTK phosphorylation. FAM150A binds LTK extracellular domain with high affinity (KD = 28 pM). FAM150A stimulates LTK phosphorylation in a ligand-dependent manner. This strategy provides an efficient approach for identifying functional ligands for other orphan receptors. PMID:25331893

  12. Targeting of the MET receptor tyrosine kinase by small molecule inhibitors leads to MET accumulation by impairing the receptor downregulation.

    Science.gov (United States)

    Leiser, Dominic; Pochon, Benoît; Blank-Liss, Wieslawa; Francica, Paola; Glück, Astrid A; Aebersold, Daniel M; Zimmer, Yitzhak; Medová, Michaela

    2014-03-03

    The MET receptor tyrosine kinase is deregulated primarily via overexpression or point mutations in various human cancers and different strategies for MET inhibition are currently evaluated in clinical trials. We observed by Western blot analysis and by Flow cytometry that MET inhibition by different MET small molecule inhibitors surprisingly increases in a dose-dependent manner total MET levels in treated cells. Mechanistically, this inhibition-related MET accumulation was associated with reduced Tyr1003 phosphorylation and MET physical association with the CBL ubiquitin ligase with concomitant decrease in MET ubiquitination. These data may suggest careful consideration for design of anti-MET clinical protocols. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  13. A novel Bruton's tyrosine kinase gene (BTK) invariant splice site mutation in a Malaysian family with X-linked agammaglobulinemia.

    Science.gov (United States)

    Chear, Chai Teng; Gill, Harvindar Kaur; Ramly, Nazatul Haslina; Dhaliwal, Jasbir Singh; Bujang, Noraini; Ripen, Adiratna Mat; Mohamad, Saharuddin Bin

    2013-12-01

    X-linked agammaglobulinemia (XLA) is a rare genetic disorder caused by mutations in the Bruton's tyrosine kinase (BTK) gene. These mutations cause defects in early B cell development. A patient with no circulating B cells and low serum immunoglobulin isotypes was studied as were his mother and sister. Monocyte BTK protein expression was evaluated by flow cytometry. The mutation was determined using PCR and followed by sequencing. Flow cytometry showed the patient lacked BTK protein expression in his monocytes while the mother and sister had 62% and 40% of the monocytes showing BTK protein expressions respectively. The patient had a novel base substitution in the first nucleotide of intron 9 in the BTK gene, and the mutation was IVS9+1Gagammaglobulinemia and may be used for subsequent genetic counseling, carrier detection and prenatal diagnosis.

  14. [Tyrosine kinase inhibiting the VEGF pathway and elderly people: Tolerance, pre-treatment assessment and side effects management].

    Science.gov (United States)

    Bretagne, Marie; Boudou-Rouquette, Pascaline; Huillard, Olivier; Thomas-Schoemann, Audrey; Chahwakilian, Anne; Orvoen, Galdric; Arrondeau, Jennifer; Tlemsani, Camille; Cessot, Anatole; Cabanes, Laure; Blanchet, Benoit; Coriat, Romain; Alexandre, Jérôme; Goldwasser, François

    2016-03-01

    Angiogenesis inhibition is a major antitumor strategy that has emerged during the last decade. Oral tyrosine kinase inhibitors (TKI) targeting the VEGF receptor, including sunitinib, sorafenib, axitinib, regorafenib, pazopanib, and vandetanib reduce tumor growth and metastasis. These agents are approved for the treatment of metastatic diseases in first or second-line. They display a narrow therapeutic index. However, data in the elderly and/or in patients with multiple illnesses remain scarce. This population is classically excluded from clinical trials. The aim of this review is to provide an overview of existing literature regarding antiangiogenic TKI tolerance in the elderly (>70 years old). We also highlight key points of the pre-therapeutic evaluation and summarize the management of common toxicities.

  15. Inibidores de tirosino quinase na leucemia mieloide crônica Tyrosine kinase inhibitors in chronic myeloid leukemia

    Directory of Open Access Journals (Sweden)

    Nei R. Lopes

    2009-01-01

    Full Text Available A leucemia mieloide crônica (LMC é uma neoplasia da medula óssea originada da translocação entre os cromossomos 9 e 22 t(9:22(q34;11 e forma o gene híbrido BCR-ABL, que possui intensa atividade tirosino quinase, sendo responsável pela proliferação das células tumorais. Um grande avanço no tratamento da LMC foi conquistado com o surgimento dos inibidores da tirosino quinase, entre eles o imatinibe, que vem demonstrando ser efetivo na maior parte dos pacientes com LMC por apresentar respostas duradouras. Entretanto, há pacientes resistentes ou que desenvolvem resistência durante o tratamento com esta droga; sendo assim, inibidores de tirosino quinase de segunda geração, como o dasatinibe e o nilotinibe, foram desenvolvidos apresentando maior potência com a finalidade de diminuir a chance de desenvolvimento de resistência. O bosutinibe e o INNO-406 estão sendo estudados para atender pacientes resistentes às drogas anteriormente citadas e também com a finalidade de diminuir efeitos colaterais das mesmas; entretanto, eles ainda estão em fase clínica de estudo. Há ainda outras drogas inibidoras da tirosino quinase que estão em desenvolvimento na fase clínica ou pré-clínica. A partir do desenvolvimento destas novas drogas, múltiplas opções de tratamento para os pacientes com LMC poderão ser propostas, podendo, desta forma, individualizar o tratamento de acordo com o que cada paciente necessita. Este estudo visa descrever as drogas antineoplásicas que têm como mecanismo de ação a inibição da enzima tirosino quinase na LMC.Chronic myeloid leukemia (CML is a neoplastic transformation of the hematopoietic system resulting from a t(9;22(q34;q11 translocation forming a BCR-ABL hybrid gene which has intense enzyme tyrosine kinase activity responsible for the proliferation of tumor cells. A dramatic positive response was achieved in CML patients with imatinib. This drug is effective in most patients because it presents long

  16. Targeting tyrosine kinases in cancer: the converging roles of cytopathology and molecular pathology in the era of genomic medicine.

    Science.gov (United States)

    Dumur, Catherine I; Idowu, Michael O; Powers, Celeste N

    2013-02-01

    Because of knowledge gained in the field of cancer biology, clinicians are currently witnessing an explosion of molecular tests as companion diagnostics to targeted therapies against growth factor receptors and their signaling pathways. Such tests are being applied increasingly to cytology specimens as essential components of genomic medicine, because less invasive diagnostic procedures are becoming the norm. The objective of this review was to present an overview of the current and future role of cytopathology in molecular diagnostics, including the adequacy of cytology specimens for such studies. The authors also discuss the critical methodologic aspects of the molecular assays used for the selection of tyrosine kinase treatment for oncology patients. Copyright © 2012 American Cancer Society.

  17. Case of soluble fms-like tyrosine kinase 1 apheresis in severe pre-eclampsia developed at 15 weeks' gestation.

    Science.gov (United States)

    Nakakita, Baku; Mogami, Haruta; Kondoh, Eiji; Tsukamoto, Tatsuo; Yanagita, Motoko; Konishi, Ikuo

    2015-10-01

    Soluble fms-like tyrosine kinase-1 (sFlt1), a circulating vascular endothelial growth factor receptor 1 antagonist, is associated with the pathogenesis of pre-eclampsia. Extracorporeal removal of sFlt1 (sFlt1 apheresis) is emerging as a treatment for pre-eclampsia. We performed sFlt1 apheresis for a patient with very early onset pre-eclampsia, beginning at 15 weeks' gestation. She underwent sFlt1 apheresis 13 times from 19 to 23 weeks' gestation. The series of treatments lowered circulating sFlt1, stabilized blood pressure, reduced urinary protein, and preserved renal function, which contributed to a successful prolongation of pregnancy for 4 weeks and a live birth at 23(+3) weeks' gestation. Further studies are necessary for clinical application of sFlt1 apheresis as sFlt1 might have a protective function for the placenta and fetus in pre-eclampsia.

  18. Melanoma-associated antigen expression and the efficacy of tyrosine kinase inhibitors in head and neck cancer

    DEFF Research Database (Denmark)

    Hartmann, Stefan; Brands, Roman C; Küchler, Nora

    2015-01-01

    Melanoma-associated antigen (MAGE) has been identified in a variety of types of cancer. The expression of several MAGE subgroups is correlated with poor prognosis and chemotherapeutic resistance. One target of chemotherapeutic treatment in head and neck cancer is the epidermal growth factor...... receptor (EGFR). The efficacy of tyrosine kinase inhibitors (TKI) in the context of melanoma-associated antigens is discussed in the present study. Five human squamous cell carcinoma cell lines were treated with the EGFR TKIs, erlotinib and gefitinib. The efficacy of these agents was measured using...... a crystal violet assay. Furthermore, the expression levels of MAGE-A1, -A5, -A8, -A9, -A11 and -A12 were determined by reverse transcription-quantitative polymerase chain reaction. The association between TKI efficacy and MAGE-A expression was analyzed by linear regression. The cell lines revealed...

  19. Dietary phytoestrogens present in soy dramatically increase cardiotoxicity in male mice receiving a chemotherapeutic tyrosine kinase inhibitor.

    Science.gov (United States)

    Harvey, Pamela Ann; Leinwand, Leslie Anne

    2015-01-05

    Use of soy supplements to inhibit cancer cell growth is increasing among patients due to the perception that phytoestrogens in soy inhibit carcinogenesis via induction of apoptosis. Genistein, the most prevalent phytoestrogen in soy, is a potent endocrine disruptor and tyrosine kinase inhibitor (TKI) that causes apoptosis in many cells types. Chemotherapeutic TKIs limit cancer cell growth via the same mechanisms. However, TKIs such as Sunitinib cause cardiotoxicity in a significant number of patients. Molecular interactions between Sunitinib and dietary TKIs like genistein have not been examined in cardiomyocytes. Significant lethality occurred in mice treated with Sunitinib and fed a phytoestrogen-supplemented diet. Isolated cardiomyocytes co-treated with genistein and Sunitinib exhibited additive inhibition of signaling molecules important for normal cardiac function and increased apoptosis compared with Sunitinib alone. Thus, dietary soy supplementation should be avoided during administration of Sunitinib due to exacerbated cardiotoxicity, despite evidence for positive effects in cancer.

  20. Structure-based discovery of novel 4,5,6-trisubstituted pyrimidines as potent covalent Bruton's tyrosine kinase inhibitors.

    Science.gov (United States)

    Zou, Yi; Xiao, Jianhu; Tu, Zhengchao; Zhang, Yingyi; Yao, Kun; Luo, Minghao; Ding, Ke; Zhang, Yihua; Lai, Yisheng

    2016-07-01

    A series of novel 4,5,6-trisubstituted pyrimidines were designed as potent covalent Bruton's tyrosine kinase (BTK) inhibitors based on the structure of ibrutinib by using a ring-opening strategy. Among these derivatives, compound I1 exhibited the most potent inhibitory activity with an IC50 value of 0.07μM. The preliminary structure-activity relationship was discussed and the primary amino group at the C-4 position of pyrimidine was crucial for maintaining BTK activity. Furthermore, molecular dynamics simulations and binding free energy calculations were performed for three inhibitor-BTK complexes to determine the probable binding model, which provided a comprehensive guide for further structural modification and optimization. Copyright © 2016 Elsevier Ltd. All rights reserved.