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K.M. Ip C, Yin J, K.S. Ng P, Lin SY, B. Mills G. Genomic-Glycosylation Aberrations in Tumor Initiation, Progression and Management. AIMS MEDICAL SCIENCE 2016. [DOI: 10.3934/medsci.2016.4.386] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Grisanti LA, Talarico JA, Carter RL, Yu JE, Repas AA, Radcliffe SW, Tang HA, Makarewich CA, Houser SR, Tilley DG. β-Adrenergic receptor-mediated transactivation of epidermal growth factor receptor decreases cardiomyocyte apoptosis through differential subcellular activation of ERK1/2 and Akt. J Mol Cell Cardiol 2014; 72:39-51. [PMID: 24566221 PMCID: PMC4037368 DOI: 10.1016/j.yjmcc.2014.02.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 01/15/2014] [Accepted: 02/12/2014] [Indexed: 02/03/2023]
Abstract
β-Adrenergic receptor (βAR)-mediated transactivation of epidermal growth factor receptor (EGFR) has been shown to relay pro-survival effects via unknown mechanisms. We hypothesized that acute βAR-mediated EGFR transactivation in the heart promotes differential subcellular activation of ERK1/2 and Akt, promoting cell survival through modulation of apoptosis. C57BL/6 mice underwent acute i.p. injection with isoproterenol (ISO)±AG 1478 (EGFR antagonist) to assess the impact of βAR-mediated EGFR transactivation on the phosphorylation of ERK1/2 (P-ERK1/2) and Akt (P-Akt) in distinct cardiac subcellular fractions. Increased P-ERK1/2 and P-Akt were observed in cytosolic, plasma membrane and nuclear fractions following ISO stimulation. Whereas the P-ERK1/2 response was EGFR-sensitive in all fractions, the P-Akt response was EGFR-sensitive only in the plasma membrane and nucleus, results confirmed in primary rat neonatal cardiomyocytes (RNCM). βAR-mediated EGFR-transactivation also decreased apoptosis in serum-depleted RNCM, as measured via TUNEL as well as caspase 3 activity/cleavage, which were sensitive to the inhibition of either ERK1/2 (PD184352) or Akt (LY-294002) signaling. Caspase 3 activity/cleavage was also sensitive to the inhibition of transcription, which, with an increase in nuclear P-ERK1/2 and P-Akt in response to ISO, suggested that βAR-mediated EGFR transactivation may regulate apoptotic gene transcription. An Apoptosis PCR Array identified tnfsf10 (TRAIL) to be altered by ISO in an EGFR-sensitive manner, results confirmed via RT-PCR and ELISA measurement of both membrane-bound and soluble cardiomyocyte TRAIL levels. βAR-mediated EGFR transactivation induces differential subcellular activation of ERK1/2 and Akt leading to increased cell survival through the modulation of caspase 3 activity and apoptotic gene expression in cardiomyocytes.
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MESH Headings
- Adrenergic beta-Agonists/pharmacology
- Animals
- Animals, Newborn
- Apoptosis/drug effects
- Apoptosis/genetics
- Caspase 3/genetics
- Caspase 3/metabolism
- Cats
- ErbB Receptors/antagonists & inhibitors
- ErbB Receptors/genetics
- ErbB Receptors/metabolism
- Gene Expression Regulation
- Isoproterenol/pharmacology
- Mice
- Mice, Inbred C57BL
- Mitogen-Activated Protein Kinase 1/genetics
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3/genetics
- Mitogen-Activated Protein Kinase 3/metabolism
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Phosphorylation
- Primary Cell Culture
- Proto-Oncogene Proteins c-akt/genetics
- Proto-Oncogene Proteins c-akt/metabolism
- Quinazolines/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Adrenergic, beta/genetics
- Receptors, Adrenergic, beta/metabolism
- Signal Transduction
- Tyrphostins/pharmacology
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Affiliation(s)
- Laurel A Grisanti
- Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Jennifer A Talarico
- Department of Pharmaceutical Sciences, Jefferson School of Pharmacy, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Rhonda L Carter
- Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Justine E Yu
- Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Ashley A Repas
- Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Scott W Radcliffe
- Department of Pharmaceutical Sciences, Jefferson School of Pharmacy, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Hoang-Ai Tang
- Department of Pharmaceutical Sciences, Jefferson School of Pharmacy, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Catherine A Makarewich
- Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Steven R Houser
- Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Douglas G Tilley
- Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA; Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
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Enhanced cornea cell growth on a keratoprosthesis material immobilized with fibronectin or EGF. Macromol Res 2012. [DOI: 10.1007/s13233-013-1022-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Allahverdian S, Wang A, Singhera GK, Wong BW, Dorscheid DR. Sialyl Lewis X modification of the epidermal growth factor receptor regulates receptor function during airway epithelial wound repair. Clin Exp Allergy 2010; 40:607-18. [PMID: 20447077 DOI: 10.1111/j.1365-2222.2010.03455.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Epidermal growth factor receptor (EGFR) is a major regulator of airway epithelial cell (AEC) functions such as migration, proliferation and differentiation, which play an essential role in epithelial repair. EGFR is a glycoprotein with 12 potential N-glycosylation sites in its extracellular domain. Glycosylation of EGFR has been shown to modulate its function. Previously, our laboratory demonstrated an important role of the carbohydrate structure sialyl Lewis x (sLe(x)) in airway epithelial repair. OBJECTIVE To examine whether an sLe(x) decoration of EGFR can modulate receptor function during AEC repair. METHODS Primary normal human bronchial epithelial (NHBE) cells were cultured in vitro. Co-localization of sLe(x) and EGFR was examined using confocal microscopy. Expressions of RNA and protein were analysed using RT-PCR and Western blotting. The final step in the synthesis of sLe(x) was catalysed by a specific alpha-1,3-fucosyltransferase (FucT-IV). To evaluate the role of sLe(x) in EGFR activation, a knockdown of the FucT-IV gene with small interfering RNA (siRNA) and an inhibitory anti-sLe(x) antibody (KM-93) was used. RESULTS We demonstrated a co-localization of sLe(x) with EGFR on NHBE cells using confocal microscopy. Using a blocking antibody for sLe(x) after a mechanical injury, we observed a reduction in EGFR phosphorylation and epithelial repair following injury. FucT-IV demonstrates a temporal expression coordinate with epithelial repair. Down-regulation of FucT-IV expression in NHBE by specific siRNA suppressed sLe(x) expression. The use of FucT-IV siRNA significantly reduced phosphorylation of EGFR and prevented epithelial repair. An immunohistochemical analysis of human normal and asthmatic airways showed a significant reduction in sLe(x) and tyrosine-phosphorylated EGFR (pY(845)-EGFR) in the epithelium of asthmatic subjects compared with that of normal subjects. CONCLUSION The present data demonstrate that sLe(x), in association with EGFR, in NHBE is coordinate with repair. This glycosylation is important in modulating EGFR activity to affect the repair of normal primary AEC.
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Affiliation(s)
- S Allahverdian
- Department of Medicine, UBC James Hogg Research Centre, Providence Heart+Lung Institute, St. Paul's Hospital, University of British Columbia, Vancouver, Canada
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Xu Y, Shao Y, Zhou J, Voorhees JJ, Fisher GJ. Ultraviolet irradiation-induces epidermal growth factor receptor (EGFR) nuclear translocation in human keratinocytes. J Cell Biochem 2009; 107:873-80. [PMID: 19415674 DOI: 10.1002/jcb.22195] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Epidermal growth factor receptor (EGFR) plays a critical role in mediating ultraviolet (UV) irradiation-induced signal transduction and gene expression in human keratinocytes. EGFR activation results from increased phosphorylation on specific tyrosine residues in the C-terminal intracellular domain. It has recently been reported that following growth factor stimulation EGFR translocates from the surface membrane to the nucleus, where it may directly regulate gene transcription. We have investigated the ability of UV irradiation to induce EGFR nuclear translocation in human primary and HaCaT keratinocytes. UV irradiation caused rapid nuclear translocation of EGFR. Significant accumulation of EGFR in the nucleus was observed within 15 min after UV irradiation exposure. Maximal translocation occurred at 30 min post-UV irradiation, and resulted in a 10-fold increase in EGFR in the nucleus, as determined by Western blot analysis of nuclear extracts and confirmed by immunofluorescence. Inhibition of nuclear export by Leptomycin B did not alter UV irradiation-induced nuclear accumulation. EGFR tyrosine kinase inhibitor (PD169540) reduced UV irradiation-induced EGFR nuclear translocation 50%. Mutation of either tyrosine 1148 or tyrosine 1173 reduced nuclear translocation 70%, while mutation of tyrosine 1068 was without effect. In addition, over-expression of receptor type protein tyrosine phosphatase-kappa (RPTP-kappa), which specifically dephosphorylates EGFR tyrosines, decreased UV irradiation-induced EGFR nuclear translocation in human keratinocytes. These data demonstrate that UV irradiation stimulates rapid EGFR nuclear translocation, which is dependent on phosphorylation of specific EGFR tyrosine residues. EGFR nuclear translocation may act in concert with conventional signaling pathways to mediate UV irradiation-induced responses in human keratinocytes.
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Affiliation(s)
- Yiru Xu
- Department of Dermatology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
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6
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Tzafriri AR, Edelman ER. Endosomal receptor kinetics determine the stability of intracellular growth factor signalling complexes. Biochem J 2007; 402:537-49. [PMID: 17117924 PMCID: PMC1863564 DOI: 10.1042/bj20060756] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
There is an emerging paradigm that growth factor signalling continues in the endosome and that cell response to a growth factor is defined by the integration of cell surface and endosomal events. As activated receptors in the endosome are exposed to a different set of binding partners, they probably elicit differential signals compared with when they are at the cell surface. As such, complete appreciation of growth factor signalling requires understanding of growth factor-receptor binding and trafficking kinetics both at the cell surface and in endosomes. Growth factor binding to surface receptors is well characterized, and endosomal binding is assumed to follow surface kinetics if one accounts for changes in pH. Yet, specific binding kinetics within the endosome has not been examined in detail. To parse the factors governing the binding state of endosomal receptors we analysed a whole-cell mathematical model of epidermal growth factor receptor trafficking and binding. We discovered that the stability of growth factor-receptor complexes within endosomes is governed by three primary independent factors: the endosomal dissociation constant, total endosomal volume and the number of endosomal receptors. These factors were combined into a single dimensionless parameter that determines the endosomal binding state of the growth factor-receptor complex and can distinguish different growth factors from each other and different cell states. Our findings indicate that growth factor binding within endosomal compartments cannot be appreciated solely on the basis of the pH-dependence of the dissociation constant and that the concentration of receptors in the endosomal compartment must also be considered.
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Affiliation(s)
- A Rami Tzafriri
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Room 16-343, Cambridge, MA 02139, USA
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Abstract
Signal transducer and activator of transcription (STAT) proteins are cytoplasmic transcription factors that translocate to the nucleus and regulate gene expression upon activation of cytokine or growth factor receptors. While this translocation event is essential for gene regulation by STATs, their mechanism of transport through the cytoplasm to the nucleus has remained elusive. We now report that cytoplasmic transport of Stat3 is an active process that requires receptor-mediated endocytosis. Stat3 co-localizes with endocytic vesicles in transit from the cell membrane to the perinuclear region in response to growth factor stimulation. Consistent with a role for receptor endocytosis in growth factor signaling, disruption of endocytosis with specific inhibitors blocks Stat3 nuclear translocation and Stat3-dependent gene regulation. These results indicate that receptor-mediated endocytosis may be a general mechanism of transport through the cytoplasm for a subset of cytoplasmic signaling proteins destined for the nucleus.
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Affiliation(s)
- Andrea H. Bild
- Department of Pharmacology, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Denver, CO 80262 and Molecular Oncology Program, H.Lee Moffitt Cancer Center and Research Institute; Departments of Oncology, Biochemistry and Molecular Biology, and Pathology, University of South Florida College of Medicine, 12902 Magnolia Drive, Tampa, FL 33612, USA Corresponding author e-mail:
| | - James Turkson
- Department of Pharmacology, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Denver, CO 80262 and Molecular Oncology Program, H.Lee Moffitt Cancer Center and Research Institute; Departments of Oncology, Biochemistry and Molecular Biology, and Pathology, University of South Florida College of Medicine, 12902 Magnolia Drive, Tampa, FL 33612, USA Corresponding author e-mail:
| | - Richard Jove
- Department of Pharmacology, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Denver, CO 80262 and Molecular Oncology Program, H.Lee Moffitt Cancer Center and Research Institute; Departments of Oncology, Biochemistry and Molecular Biology, and Pathology, University of South Florida College of Medicine, 12902 Magnolia Drive, Tampa, FL 33612, USA Corresponding author e-mail:
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9
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Abstract
During interphase the transport of material between different intracellular organelles requires accurate regulation of fusiogenic domains. Recent studies on hepatic endosomes indicated that compartmentalized Cdk2 cyclin E complexes act by braking fusion events. These Cdk2 complexes integrate tyrosine phosphorylation and dephosphory lation inputs, resulting in the control of the number of rounds of fusion at discrete domains. This leads to changes in the intracellular location of internalized receptors and ultimately their biological response.Key words: vesicular traffic, Cdk2, receptors tyrosine kinases.
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Lin SY, Makino K, Xia W, Matin A, Wen Y, Kwong KY, Bourguignon L, Hung MC. Nuclear localization of EGF receptor and its potential new role as a transcription factor. Nat Cell Biol 2001; 3:802-8. [PMID: 11533659 DOI: 10.1038/ncb0901-802] [Citation(s) in RCA: 799] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epidermal growth factor receptor (EGFR) has been detected in the nucleus in many tissues and cell lines. However, the potential functions of nuclear EGFR have largely been overlooked. Here we demonstrate that nuclear EGFR is strongly correlated with highly proliferating activities of tissues. When EGFR was fused to the GAL4 DNA-binding domain, we found that the carboxy terminus of EGFR contained a strong transactivation domain. Moreover, the receptor complex bound and activated AT-rich consensus-sequence-dependent transcription, including the consensus site in cyclin D1 promoter. By using chromatin immunoprecipitation assays, we further demonstrated that nuclear EGFR associated with promoter region of cyclin D1 in vivo. EGFR might therefore function as a transcription factor to activate genes required for highly proliferating activities.
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Affiliation(s)
- S Y Lin
- Department of Molecular and Cellular Oncology, Breast Cancer Basic Research Program, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
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Wang XQ, Sun P, O'Gorman M, Tai T, Paller AS. Epidermal growth factor receptor glycosylation is required for ganglioside GM3 binding and GM3-mediated suppression [correction of suppresion] of activation. Glycobiology 2001; 11:515-22. [PMID: 11447130 DOI: 10.1093/glycob/11.7.515] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Gangliosides are able to bind to the epidermal growth factor receptor and inhibit its activation, but the mechanism of this inhibition is unknown. To address the role of receptor carbohydrates in facilitating interaction with gangliosides, we examined the ability of GM3 to bind the deglycosylated receptor and inhibit its autophosphorylation. Flow cytometry studies demonstrated that deglycosylation of the receptor did not affect its ability to be transported to the cell membrane. In contrast with the native (fully glycosylated) receptor, GM3 did not coimmunoprecipitate with the deglycosylated receptor. Using a novel colorimetric bead binding assay, GM3 was shown to bind well to the immunoprecipitated native receptor but not at all to the deglycosylated receptor. Finally, the addition of GM3 to cells with deglycosylated epidermal growth factor receptors did not result in significant further inhibition of autophosphorylation of the receptor, despite a 10-fold decrease in phosphorylation of the native epidermal growth factor receptor by 200 microM GM3. These studies suggest that ganglioside affects epidermal growth factor receptor activity through a direct interaction that requires receptor glycosylation, and contribute to our understanding of the role of gangliosides in cell membrane function.
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Affiliation(s)
- X Q Wang
- Department of Pediatrics, Children's Memorial Hospital, Institute for Education and Research, Northwestern University Medical School, 2300 Children's Plaza, Chicago, IL 60614, USA
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12
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Abstract
Ligand binding to plasma membrane receptors initiates a series of events culminating in a variety of changes in cellular phenotypes. Although numerous publications have documented the activation/inactivation of signalling molecules following receptor binding, relatively few investigations have focused on the cellular compartment responsible for either initiating or selecting the particular pathway that mediates the response. Specifically, does receptor signalling occur only at the plasma membrane; is signalling dependent upon the location of defined endosome populations; or are components of both plasma membrane and endosomal activity operative depending upon the particular signalling pathway or cell type? This review addresses aspects of these questions by discussing the evidence supporting or contrasting the interplay between the endocytic and signalling systems for a subset of tyrosine kinase, serine/threonine kinase and G-protein-coupled receptors.
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Affiliation(s)
- E B Leof
- Depts of Medicine and Biochemistry and Molecular Biology, Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN 55905, USA.
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Meuillet EJ, Mania-Farnell B, George D, Inokuchi JI, Bremer EG. Modulation of EGF receptor activity by changes in the GM3 content in a human epidermoid carcinoma cell line, A431. Exp Cell Res 2000; 256:74-82. [PMID: 10739654 DOI: 10.1006/excr.1999.4509] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Gangliosides have been described as modulators of growth factor receptors. For example, GM3 addition in cell culture medium inhibits epidermal growth factor (EGF)-stimulated receptor autophosphorylation. Furthermore, depletion of ganglioside by sialidase gene transfection appeared to increase EGF receptor (EGFR) autophosphorylation. These data suggested that changes in GM3 content may result in different responses to EGF. In this study, the ceramide analog d-threo-1-phenyl-2-decannoylamino-3-morpholino-1-propanol ([D]-PDMP), which inhibits UDP-glucose-ceramide glucosyltransferase, and addition of GM3 to the culture medium were used to study the effects of GM3 on the EGFR. Addition of 10 microM [D]-PDMP to A431 cells resulted in significant GM3 depletion. Additionally, EGFR autophosphorylation was increased after EGF stimulation. When exogenous GM3 was added in combination with [D]-PDMP, the enhanced EGFR autophosphorylation was returned to control levels. [D]-PDMP also increased EGF-induced cell proliferation, consistent with its effect on autophosphorylation. Once again, the addition of GM3 in combination with [D]-PDMP reversed these effects. These results indicate that growth factor receptor functions can be modulated by the level of ganglioside expression in cell lines. Addition of GM3 inhibits EGFR activity and decrease of GM3 levels using [D]-PDMP treatment enhances EGFR activity. Modulation of growth factor receptor function may provide an explanation for how transformation-dependent ganglioside changes contribute to the transformed phenotype.
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Affiliation(s)
- E J Meuillet
- The Brain Tumor Research Program, Children's Memorial Medical Center, Chicago, Illinois 60614, USA
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Liang YC, Lin-shiau SY, Chen CF, Lin JK. Suppression of extracellular signals and cell proliferation through EGF receptor binding by (−)-epigallocatechin gallate in human A431 epidermoid carcinoma cells. J Cell Biochem 1997. [DOI: 10.1002/(sici)1097-4644(19971001)67:1%3c55::aid-jcb6%3e3.0.co;2-v] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Liang YC, Lin-shiau SY, Chen CF, Lin JK. Suppression of extracellular signals and cell proliferation through EGF receptor binding by (-)-epigallocatechin gallate in human A431 epidermoid carcinoma cells. J Cell Biochem 1997; 67:55-65. [PMID: 9328839 DOI: 10.1002/(sici)1097-4644(19971001)67:1<55::aid-jcb6>3.0.co;2-v] [Citation(s) in RCA: 215] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Tea polyphenols are known to inhibit a wide variety of enzymatic activities associated with cell proliferation and tumor progression. The molecular mechanisms of antiproliferation are remained to be elucidated. In this study, we investigated the effects of the major tea polyphenol (-)-epigallocatechin gallate (EGCG) on the proliferation of human epidermoid carcinoma cell line, A431. Using a [3H]thymidine incorporation assay, EGCG could significantly inhibit the DNA synthesis of A431 cells. In vitro assay, EGCG strongly inhibited the protein tyrosine kinase (PTK) activities of EGF-R, PDGF-R, and FGF-R, and exhibited an IC50 value of 0.5-1 microgram/ml. But EGCG scarcely inhibited the protein kinase activities of pp60v-src, PKC, and PKA (IC50 > 10 micrograms/ml). In an in vivo assay, EGCG could reduce the autophosphorylation level of EGF-R by EGF. Phosphoamino acid analysis of the EGF-R revealed that EGCG inhibited the EGF-stimulated increase in phosphotyrosine level in A431 cells. In addition, we showed that EGCG blocked EGF binding to its receptor. The results of further studies suggested that the inhibition of proliferation and suppression of the EGF signaling by EGCG might mainly mediate dose-dependent blocking of ligand binding to its receptor, and subsequently through inhibition of EGF-R kinase activity.
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Affiliation(s)
- Y C Liang
- Institute of Biochemistry, College of Medicine, National Taiwan University, Taipei, Republic of China
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Chen G, Ito Y, Imanishi Y. Photo-immobilization of epidermal growth factor enhances its mitogenic effect by artificial juxtacrine signaling. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1358:200-8. [PMID: 9332456 DOI: 10.1016/s0167-4889(97)00065-7] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Photo-reactive epidermal growth factor (EGF) was synthesized by coupling EGF with azidobenzoic acid and was immobilized onto the wells of a polystyrene culture plate by photo-irradiation. The photo-immobilized EGF enhanced the growth of anchorage-dependent cells more than native or azidobenzoyl derivatized EGF. A small amount of photo-immobilized EGF was sufficient to enhance the growth of cells and the maximal mitogenic effect was greater than that of native or derivatized EGF. On the other hand, the photo-immobilized EGF did not enhance growth of anchorage-independent cells. In addition, signal transduction in the cells adhered only on the EGF-immobilized surface was observed by staining of phosphotyrosine residues by anti-phosphotyrosine antibodies. These results showed that the enhanced cell growth was due to direct interaction between the cells and the immobilized EGF. Photo-immobilization could be a universal means of fixing growth factors onto an artificial matrix that is devoid of chemically functional groups scaffolding growth factors and could provide a new tool to elucidate signal transduction mechanism and could lead to the development of a new protein-free cell culture system or tissue engineering materials.
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Affiliation(s)
- G Chen
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Japan
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17
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Rebbaa A, Yamamoto H, Saito T, Meuillet E, Kim P, Kersey DS, Bremer EG, Taniguchi N, Moskal JR. Gene transfection-mediated overexpression of beta1,4-N-acetylglucosamine bisecting oligosaccharides in glioma cell line U373 MG inhibits epidermal growth factor receptor function. J Biol Chem 1997; 272:9275-9. [PMID: 9083062 DOI: 10.1074/jbc.272.14.9275] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
N-linked oligosaccharides appear to be important for the function of the epidermal growth factor (EGF) receptor. In a previous study (Rebbaa, A., Yamamoto, H., Moskal, J. R., and Bremer, E. G. (1996) J. Neurochem. 67, 2265-2272), we showed that binding of the erythroagglutinating phytohemagglutin lectin from Phaseolus vulgaris to the bisecting structures on the EGF receptor from U373 MG glioma cells blocked EGF binding and receptor autophosphorylation. In this study we examined the consequences of overexpression of the bisecting structure on the EGF receptor by gene transfection of U373 MG cells with the N-acetylglucosaminyltransferase III (GnT-III). This modification leads to a significant decrease in EGF binding and EGF receptor autophosphorylation. In addition, the cellular response to EGF was found to be altered. Proliferation of U373 MG cells in serum-free medium is inhibited by EGF. In contrast, proliferation of the GnT-III-transfected cells was stimulated by EGF. These data demonstrate that changes in EGF receptor glycosylation by GnT-III transfection reduces the number of the active receptors in U373 MG cells and that this change results in change in the cellular response to EGF.
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Affiliation(s)
- A Rebbaa
- Brain Tumor Research Program, Children's Memorial Hospital, Chicago Institute for Neurosurgery and Neuroresearch, Chicago, Illinois 60614, USA
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Abstract
Transforming growth factor alpha (TGF alpha) and epidermal growth factor (EGF) bind to the same receptor, but have different potencies and actions. A possible mechanism is that differences in processing may be responsible for their divergent properties. We have examined TGF alpha and EGF processing in isolated rat hepatocytes with and without various protease inhibitors and inhibitors of endosomal processing. Our results show that EGF undergoes limited degradation in endosomes and is primarily degraded in lysosomes. In contrast, TGF alpha is rapidly degraded in endosomes by insulin-degrading enzyme (EC 3.4.24.56), possibly allowing rapid return of the receptor to the cell surface. Incubation of isolated endosomes preloaded with labeled TGF alpha reveals that degradation can occur whether the vesicles are acidified or not, as is also the case for insulin. We conclude that TGF alpha is degraded immediately after internalization, at least partly before acidification has occurred, while EGF requires prolonged intracellular residence and lysosomal degradation. The different degradation pathways may play a role in the different activities of the two hormones.
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Affiliation(s)
- F G Hamel
- Research Service, Department of Veterans Affairs Medical Center-R151, Omaha, NE 68105, USA
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19
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Allevato G, Billestrup N, Goujon L, Galsgaard ED, Norstedt G, Postel-Vinay MC, Kelly PA, Nielsen JH. Identification of phenylalanine 346 in the rat growth hormone receptor as being critical for ligand-mediated internalization and down-regulation. J Biol Chem 1995; 270:17210-4. [PMID: 7615519 DOI: 10.1074/jbc.270.29.17210] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The functional significance of growth hormone (GH) receptor (GHR) internalization is unknown; therefore, we have analyzed domains and individual amino acids in the cytoplasmic region of the rat GHR required for ligand-mediated receptor internalization, receptor down-regulation, and transcriptional signaling. When various mutated GHR cDNAs were transfected stably into Chinese hamster ovary cells or transiently into monkey kidney (COS-7) cells, internalization of the GHR was found to be dependent upon a domain located between amino acids 318 and 380. Mutational analysis of aromatic residues in this domain revealed that phenylalanine 346 is required for internalization. Receptor down-regulation in transiently transfected COS-7 cells was also dependent upon the phenylalanine 346 residue of the GHR, since no GH-induced down-regulation was observed in cells expressing the F346A GHR mutant. In contrast, the ability to stimulate transcription of the serine protease inhibitor 2.1 promoter by the GHR was not affected by the phenylalanine 346 to alanine mutation. These results demonstrate that phenylalanine 346 is essential for GHR internalization and down-regulation but not for transcriptional signaling, suggesting that ligand-mediated endocytosis is not a prerequisite for GH-induced gene transcription.
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Affiliation(s)
- G Allevato
- Hagedorn Research Institute, Gentofte, Denmark
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Grady EF, Slice LW, Brant WO, Walsh JH, Payan DG, Bunnett NW. Direct observation of endocytosis of gastrin releasing peptide and its receptor. J Biol Chem 1995; 270:4603-11. [PMID: 7876231 DOI: 10.1074/jbc.270.9.4603] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Endocytosis of the gastrin releasing peptide receptor (GRP-R) may regulate cellular responses to GRP. We observed endocytosis in transfected epithelial cells by confocal microscopy using cyanine 3-GRP (cyanine 3.18-labeled gastrin releasing peptide) and GRP-R antibodies. At 4 degrees C, cy3-GRP and GRP-R were confined to the plasma membrane. After 5 min at 37 degrees C, ligand and receptor were internalized into early endosomes with fluorescein isothiocyanate-transferrin. After 10 min, cy3-GRP and GRP-R were in perinuclear vesicles, and at 60 min cy3-GRP was in large, central vesicles, while GRP-R was at the cell surface. We quantified surface GRP-R using an antibody to an extracellular epitope and an 125I-labeled secondary antibody. After exposure to GRP, there was a loss and subsequent recovery of surface GRP-R. Recovery was unaffected by cycloheximide, and thus independent of new protein synthesis, but was attenuated by acidotropic agents, and therefore required endosomal acidification. Internalization of 125I-GRP, assessed using an acid wash, was maximal after 10-20 min, and was clathrin-mediated since it was inhibited by hyperosmolar sucrose and phenylarsine oxide. Thus, GRP and its receptor are rapidly internalized into early endosomes and then dissociate in an acidified compartment. GRP is probably degraded whereas the GRP-R recycles.
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Affiliation(s)
- E F Grady
- Department of Surgery, University of California, San Francisco 94143
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21
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Adler S. Heparin alters epidermal growth factor metabolism in cultured rat glomerular epithelial cells. THE AMERICAN JOURNAL OF PATHOLOGY 1991; 139:169-75. [PMID: 1853931 PMCID: PMC1886138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Extracellular matrix plays an important role in regulating cell growth. The authors have previously shown that heparin and heparan sulfate inhibit glomerular visceral epithelial cell (GEC) growth and that epidermal growth factor (EGF) can partially reverse the effect of heparin. The authors studied EGF processing by GEC in an attempt to clarify the mechanism by which heparin inhibits GEC growth. Control and heparin-treated GEC rapidly internalized 125I-EGF (within 15 minutes). In heparin-treated cells, 125I-EGF reappeared on the cell surface during the course of a 1-hour incubation and the percent internalized dropped significantly to 59.0% +/- 8.6%, suggesting recycling of 125I-EGF-occupied receptors. After incubation with 125I-EGF, heparin-treated cells also released significantly more cpm of 125I into EGF-free medium (2526 +/- 68 cpm-H; 903 +/- 32-C). Analysis of the released 125I by gel filtration chromatography showed more totally degraded 125I-EGF in media from heparin-treated cells (30.8% +/- 1.6% in heparin-treated versus 17.8% +/- 3.2 in control; P less than 0.05). Analysis of EGF-induced dimerization of receptors showed no effect of heparin on this ratio. These studies suggest that heparin decreases GEC response to EGF by accelerating its uptake and degradation. Matrix alterations in disease states may thus play a role in altering cell responsiveness to growth factors.
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Affiliation(s)
- S Adler
- Department of Medicine, New York Medical College, Valhalla
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22
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Duprez V, Ferrer M, Cornet V, Olive D, Dautry-Varsat A. Modulation of interleukin 2 internalization and interleukin 2-dependent cell growth by antireceptor antibodies. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)52322-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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23
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Shiba T, Tobe K, Koshio O, Yamamoto R, Shibasaki Y, Matsumoto N, Toyoshima S, Osawa T, Akanuma Y, Takaku F. Concanavalin A-induced receptor aggregation stimulates the tyrosine kinase activity of the insulin receptor in intact cells. Biochem J 1990; 267:787-94. [PMID: 2339989 PMCID: PMC1131367 DOI: 10.1042/bj2670787] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Concanavalin A (ConA) stimulated the phosphorylation of the beta-subunit of the insulin receptor and an Mr-185,000 protein on serine and tyrosine residues in intact H-35 rat hepatoma cells. This Mr-185,000 protein whose phosphorylation was stimulated by ConA was identical to pp185, a protein reported previously to be a putative endogenous substrate for the insulin receptor tyrosine kinase in rat hepatoma cells. In Chinese hamster ovary (CHO) cells transfected with cDNA of the human insulin receptor, tyrosine-phosphorylation of pp185 was strongly enhanced by ConA compared with the controls, suggesting that the induction of tyrosine-phosphorylation of pp185 was due to stimulation of the insulin receptor kinase by ConA. Moreover, monovalent ConA only slightly induced the tyrosine-phosphorylation of pp185, which was enhanced by the addition of anti-ConA IgG, suggesting that ConA stimulated the insulin receptor kinase mainly by the receptor cross-linking or aggregation in intact cells. These data suggest that the insulin-mimetic action of ConA is related to the autophosphorylation and activation of the insulin receptor tyrosine kinase, as well as the subsequent phosphorylation of pp185 in intact cells.
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Affiliation(s)
- T Shiba
- Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan
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24
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Wells A, Welsh JB, Lazar CS, Wiley HS, Gill GN, Rosenfeld MG. Ligand-induced transformation by a noninternalizing epidermal growth factor receptor. Science 1990; 247:962-4. [PMID: 2305263 DOI: 10.1126/science.2305263] [Citation(s) in RCA: 337] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Identification of a mutant epidermal growth factor (EGF) receptor that does not undergo downregulation has provided a genetic probe to investigate the role of internalization in ligand-induced mitogenesis. Contact-inhibited cells expressing this internalization-defective receptor exhibited a normal mitogenic response at significantly lower ligand concentrations than did cells expressing wild-type receptors. A transformed phenotype and anchorage-independent growth were observed at ligand concentrations that failed to elicit these responses in cells expressing wild-type receptors. These findings imply that activation of the protein tyrosine kinase activity at the cell membrane is sufficient for the growth-enhancing effects of EGF. Thus, downregulation can serve as an attenuation mechanism, without which transformation ensues.
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Affiliation(s)
- A Wells
- Department of Pathology, University of California-San Diego, La Jolla 92093
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25
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Decker SJ. Epidermal growth factor-induced truncation of the epidermal growth factor receptor. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(19)84617-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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26
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Werb Z, Tremble PM, Behrendtsen O, Crowley E, Damsky CH. Signal transduction through the fibronectin receptor induces collagenase and stromelysin gene expression. J Cell Biol 1989; 109:877-89. [PMID: 2547805 PMCID: PMC2115739 DOI: 10.1083/jcb.109.2.877] [Citation(s) in RCA: 832] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We have investigated the effects of ligation of the fibronectin receptor (FnR) on gene expression in rabbit synovial fibroblasts. Monoclonal antibodies to the FnR that block initial adhesion of fibroblasts to fibronectin induced the expression of genes encoding the secreted extracellular matrix-degrading metalloproteinases collagenase and stromelysin. That induction was a direct consequence of interaction with the FnR was shown by the accumulation of mRNA for stromelysin and collagenase. Monoclonal antibodies to several other membrane glycoprotein receptors had no effect on metalloproteinase gene expression. Less than 2 h of treatment of the fibroblasts with anti-FnR in solution was sufficient to trigger the change in gene expression, and induction was blocked by dexamethasone. Unlike other inducers of metalloproteinase expression, including phorbol diesters and growth factors, addition of the anti-FnR in solution to cells adherent to serum-derived adhesion proteins or collagen produced no detectable change in cell shape or actin microfilament organization. Inductive effects were potentiated by cross-linking of the ligand. Fab fragments of anti-FnR were ineffective unless cross-linked or immobilized on the substrate. Adhesion of fibroblasts to native fibronectin did not induce metallo-proteinases. However, adhesion to covalently immobilized peptides containing the arg-gly-asp sequence that were derived from fibronectin, varying in size from hexapeptides up to 120 kD, induced collagenase and stromelysin gene expression. This suggests that degradation products of fibronectin are the natural inductive ligands for the FnR. These data demonstrate that signals leading to changes in gene expression are transduced by the FnR, a member of the integrin family of extracellular matrix receptors. The signaling of changes in gene expression by the FnR is distinct from signaling involving cell shape and actin cytoarchitecture. At least two distinct signals are generated: the binding of fibronectin-derived fragments and adhesion-blocking antibodies to the FnR triggers events different from those triggered by binding of the native fibronectin ligand. Because the genes regulated by this integrin are for enzymes that degrade the extracellular matrix, these results suggest that information transduced by the binding of various ligands to integrins may orchestrate the expression of genes regulating cell behavior in the extracellular environment.
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Affiliation(s)
- Z Werb
- Laboratory of Radiobiology and Environmental Health, University of California, San Francisco 94143
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27
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Mogensen KE, Uzé G, Eid P. The cellular receptor of the alpha-beta interferons. EXPERIENTIA 1989; 45:500-8. [PMID: 2525481 DOI: 10.1007/bf01990498] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
This is a selective review of recent trends in research on the cellular receptor for the alpha-beta interferons. It deals mainly with work published in the last three years (1985-88), and therefore mainly with receptors for the human interferons. The binding characteristics of several human alpha interferons are examined, and the importance of in vitro experimental models for establishing the relationship between receptor binding and the cellular response is emphasized.
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Affiliation(s)
- K E Mogensen
- Laboratoire d'Oncologie Virale, CNRS ER 274, Villejuif, France
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28
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Isenberg WM, McEver RP, Phillips DR, Shuman MA, Bainton DF. Immunogold-surface replica study of ADP-induced ligand binding and fibrinogen receptor clustering in human platelets. THE AMERICAN JOURNAL OF ANATOMY 1989; 185:142-8. [PMID: 2773809 DOI: 10.1002/aja.1001850207] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Platelet cohesion requires the binding of fibrinogen to its receptor, a heterodimer consisting of the plasma-membrane glycoproteins GPIIb and GPIIIa. Although the GPIIb-IIIa complex is present on the surface of unstimulated platelets, it binds fibrinogen only after platelet activation. We have used an immunogold-surface replica technique to study the distribution of GPIIb-IIIa and bound fibrinogen over broad expanses of surface membranes in unstimulated and ADP-activated human platelets. We found that the gold prove was monodispersed over the surface of unstimulated platelets, although the cell surface lacked immunoreactive fibrinogen. To ascertain whether the receptors clustered prior to ligand binding or as a consequence thereof, we studied the surface distribution of GPIIb-IIIa after stimulation with ADP, which causes activation of the fibrinogen receptor function of GPIIb-IIIa without inducing the secretion of fibrinogen. In the absence of added fibrinogen, the unoccupied, yet binding-competent receptors on ADP-stimulated platelets were monodispersed. The addition of fibrinogen caused the GPIIb-IIIa molecules to cluster on the cell surface. Clustering was also induced by the addition of the GPIIb-IIIa binding domains of fibrinogen--namely, the tetrapeptide Arg-Gly-Asp-Ser on the alpha-chain or the gamma-chain decapeptide gamma 402-411. These results show that receptor occupancy causes clustering of GPIIb-IIIa in activated platelets.
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Affiliation(s)
- W M Isenberg
- Department of Pathology, University of California, San Francisco 94143
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29
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Effect of inhibitors of polyamine biosynthesis and of exogenous polyamines on mitogenic effect of epidermal growth factor in primary hepatocyte culture. Bull Exp Biol Med 1989. [DOI: 10.1007/bf00842064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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30
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31
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Rozengurt E. Bombesin-induction of cell proliferation in 3T3 cells. Specific receptors and early signaling events. Ann N Y Acad Sci 1988; 547:277-92. [PMID: 2853592 DOI: 10.1111/j.1749-6632.1988.tb23896.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- E Rozengurt
- Imperial Cancer Research Fund, London, United Kingdom
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32
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Dejana E, Colella S, Conforti G, Abbadini M, Gaboli M, Marchisio PC. Fibronectin and vitronectin regulate the organization of their respective Arg-Gly-Asp adhesion receptors in cultured human endothelial cells. J Cell Biol 1988; 107:1215-23. [PMID: 2458362 PMCID: PMC2115300 DOI: 10.1083/jcb.107.3.1215] [Citation(s) in RCA: 213] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Human umbilical vein endothelial cells (ECs) adhere in vitro to proteins of the extracellular matrix including fibronectin (fn) and vitronectin (vn). Specific receptors for fn and vn have been previously characterized. These receptors belong to a family of membrane glycoproteins characterized (a) by being a transmembrane complex of two noncovalently linked subunits and (b) by recognizing the tripeptide Arg-Gly-Asp on their respective ligands. In this paper we investigated how vn and fn control the organization of their respective receptors over the surface of ECs. It was found that the clustering of individual receptors and the organization thereafter of focal contacts occurred only when ECs were exposed to the specific ligand and did not occur on the opposite ligand. The shape of receptor clusters was slightly different and a colocalization of the two receptors was found when ECs were cultured on a mixed matrix of fn plus vn. Adhesion was selectively inhibited by vn or fn receptor antibodies on their respective substrates. The clustering of both receptors preceded the association of vinculin with focal contacts and stress fiber formation. Also, the vn receptor, in the absence of associated fn receptor, was capable of inducing the organization of the membrane-microfilament interaction complex. Overall, these results indicate that individual matrix ligands induce only the clustering of their respective membrane receptors. The clustering of only one receptor is capable of supporting the subsequent formation of focal contacts and the local assembly of related cytoskeletal proteins.
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Affiliation(s)
- E Dejana
- Istituto di Richerche Farmacologiche Mario Negri, Milano, Italy
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33
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Woll PJ, Rozengurt E. Bombesin and bombesin antagonists: studies in Swiss 3T3 cells and human small cell lung cancer. Br J Cancer 1988; 57:579-86. [PMID: 2841962 PMCID: PMC2246472 DOI: 10.1038/bjc.1988.132] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Bombesins are potent growth factors for murine Swiss 3T3 cells. Using these cells in chemically defined conditions we have been able to characterise the bombesin receptor and the early signals preceding DNA synthesis. We describe two substance P analogues [DArg1, DPro2, DTrp7,9, Leu11] substance P and [DArg1, DPhe5, DTrp7,9, Leu11] substance P which competitively block the binding of bombesins to their receptor and all the events leading to mitogenesis. Bombesins are secreted by human small cell lung cancers (SCLC) and may act as autocrine growth factors for these tumours, so the development of peptide bombesin antagonists could have therapeutic implications. We demonstrate that the antagonists can reversibly inhibit the growth of SCLC in vitro, with relatively little effect on other lung tumours.
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Affiliation(s)
- P J Woll
- Imperial Cancer Research Fund, Lincoln's Inn Fields, London, UK
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34
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Faltynek CR, Princler GL, Ruscetti FW, Birchenall-Sparks M. Lectins modulate the internalization of recombinant interferon-alpha A and the induction of 2‘,5‘-oligo(A) synthetase. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68612-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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35
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Cooper JL, Wakshull E, Wharton W. Characterization of the rebinding of 125I-epidermal growth factor released from BALB/c-3T3 cells following accumulation in the presence of chloroquine. J Cell Physiol 1988; 134:387-95. [PMID: 3258311 DOI: 10.1002/jcp.1041340309] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Lysosomotropic amines, such as chloroquine and methylamine, increase the intracellular accumulation of 125I-EGF by inhibiting lysosomal degradation. It has been shown previously that BALB/c-3T3 cells, prelabeled at 4 degrees C with 125I-EGF for 3 h and subsequently chased at 37 degrees C in the presence of chloroquine, internalized the surface bound 125I-EGF which was subsequently released into the extracellular medium in a high molecular weight form which co-migrated with native 125I-EGF. The secreted 125I-EGF rebound to the cells from which it was released more efficiently than does peptide in the extracellular media. We now show that when the BALB/c-3T3 cells were prelabeled at 37 degrees C for 2 h in the presence of chloroquine, the internalized 125I-EGF released into the medium was in a high molecular weight form which co-migrated with native 125I-EGF and did not rebind anymore efficiently than did peptide in the extracellular media. This lack of rebinding was not due to an alteration in the 125I-EGF molecule since it was still capable of rebinding to naive A431 cells, nor was it due to the exhaustion of EGF receptors on the BALB/c-3T3 cells. The inhibition of rebinding was observed only when the cells were treated with EGF in the presence of chloroquine, and was not due to a general down-regulation of membrane receptors. The differences between the rebinding of 125I-EGF at 4 degrees C and 37 degrees C suggest that EGF may be processed via different pathways in the cell.
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Affiliation(s)
- J L Cooper
- University of California, Los Alamos National Laboratory, New Mexico 87545
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36
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Uze G, Bandu MT, Eid P, Grütter M, Mogensen KE. Electrostatic interactions in the cellular dynamics of the interferon-receptor complex. EUROPEAN JOURNAL OF BIOCHEMISTRY 1988; 171:683-91. [PMID: 2964368 DOI: 10.1111/j.1432-1033.1988.tb13840.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Using membrane preparations of the interferon receptor, prepared from cells of the Burkitt line, Daudi, we have examined the binding of three human recombinant alpha-interferons. 1. We discovered a binding titration of the interferons IFN-alpha A and IFN-alpha D in the pH range 6-9. Receptor binding, negligible at pH 6, rises to a maximum close to pH 9. We have shown that binding of IFN-alpha A at basic pH is to the same receptors as at neutrality and that IFN-receptor complexes extracted with digitonin are more stable at basic pH than they are at neutrality. 2. The recombinant interferon, IFN-alpha B, shows little change of binding in the pH range 6-9. At its basic optimum the binding of IFN-alpha A approaches that of IFN-alpha B, while at neutral pH the binding of IFN-alpha A is 3-4 times less. This difference at neutral pH is seen on intact cells as well as on membrane preparations. The specific activity of IFN-alpha B is close to that of IFN-alpha A, both of which are 10-20 times more active than IFN-alpha D; and the binding titration is, therefore, independent of the initial binding affinities. 3. Using hybrid IFNs constructed from the DNA sequences of alpha D and alpha B, we have isolated the sequence responsible for the binding titration to the segment comprising amino acids 61-92. Examination of these sequences reveals that Lys-84 is present in all the IFN-alpha except IFN-alpha B where it is replaced by Glu; and Tyr-90, present in most of the common IFN-alpha including alpha A and alpha D, is replaced by Asp in IFN-alpha B. Lys and Tyr would normally titrate in the pH range 6-9. We conclude that the binding titration is due to an electrostatic interaction and we propose that the interaction is between IFN-receptor complexes. The role of the interaction in the binding losses that accompany the antiproliferative effects of IFN is discussed.
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Affiliation(s)
- G Uze
- Laboratoire d'Oncologie Virale, Institut de Recherches Scientifiques sur le Cancer, Villejuif, France
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37
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Decker SJ. Epidermal growth factor induces internalization but not degradation of the epidermal growth factor receptor in a human breast cancer cell line. JOURNAL OF RECEPTOR RESEARCH 1988; 8:853-70. [PMID: 3057191 DOI: 10.3109/10799898809049030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Metabolism of the epidermal growth factor (EGF) receptor was studied in the MDA-MB-231 human breast cancer cell line. As in normal fibroblasts the EGF receptor from MDA-MB-231 cells was synthesized from a Mr = 160,000 precursor and tunicamycin treatment of cells resulted in accumulation of a Mr = 130,000 polypeptide. Unlike normal fibroblasts in which a Mr = 170,000 mature form of the EGF receptor was found, MDA-MB-231 cells contained a Mr = 172,000 mature form. Addition of EGF to MDA-MB-231 cells led to rapid internalization of EGF receptors, however, internalization did not affect receptor half-life and receptors did not recycle to the cell surface. EGF receptors could be visualized by immunofluorescence and remained sequestered in intracellular membranous structures following internalization. EGF was degraded slowly by MDA-MB-231 cells relative to degradation of EGF by normal cells. A high endogenous level of in vivo phosphorylation of threonine 654 of the EGF receptor was found in MDA-MB-231 cells and treatment of cells with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) further stimulated phosphorylation of this residue. EGF induced receptor internalization resulted in dephosphorylation of threonine 654. The significance of these unusual properties of EGF receptor metabolism in MDA-MB-231 cells is discussed.
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Affiliation(s)
- S J Decker
- Rockefeller University, New York, NY 10021
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38
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Isenberg WM, McEver RP, Phillips DR, Shuman MA, Bainton DF. The platelet fibrinogen receptor: an immunogold-surface replica study of agonist-induced ligand binding and receptor clustering. J Cell Biol 1987; 104:1655-63. [PMID: 3584243 PMCID: PMC2114491 DOI: 10.1083/jcb.104.6.1655] [Citation(s) in RCA: 131] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Platelet aggregation requires the binding of fibrinogen to its receptor, a heterodimer consisting of the plasma-membrane glycoproteins (GP) IIb and IIIa. Although the GPIIb-IIIa complex is present on the surface of unstimulated platelets, it binds fibrinogen only after platelet activation. We have used an immunogold-surface replica technique to study the distribution of GPIIb-IIIa and bound fibrinogen over broad areas of surface membranes in unstimulated, as well as thrombin-activated and ADP-activated human platelets. We found that the immunogold-labeled GPIIb-IIIa was monodispersed over the surface of unstimulated platelets, although the cell surface lacked immunoreactive fibrinogen. On thrombin-stimulated platelets, approximately 65% of the GPIIb-IIIa molecules were in clusters within the plane of the membrane. Fibrinogen, which had been released from the alpha-granules of these cells, bound to GPIIb-IIIa on the cell surface and was similarly clustered. To determine whether the receptors clustered before ligand binding, or as a consequence thereof, we studied the surface distribution of GPIIb-IIIa after stimulation with ADP, which causes activation of the fibrinogen receptor function of GPIIb-IIIa without inducing the release of fibrinogen. In the absence of added fibrinogen, the unoccupied, yet binding-competent receptors on ADP-stimulated platelets were monodispersed. The addition of fibrinogen caused the GPIIb-IIIa molecules to cluster on the cell surface. Clustering was also induced by the addition of the GPIIb-IIIa-binding domains of fibrinogen, namely the tetrapeptide Arg-Gly-Asp-Ser on the alpha-chain or the gamma-chain decapeptide gamma 402-411. These results show that receptor occupancy causes clustering of GPIIb-IIIa in activated platelets.
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39
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Gladhaug IP, Christoffersen T. Kinetics of epidermal growth factor binding and processing in isolated intact rat hepatocytes. Dynamic externalization of receptors during ligand internalization. EUROPEAN JOURNAL OF BIOCHEMISTRY 1987; 164:267-75. [PMID: 3494603 DOI: 10.1111/j.1432-1033.1987.tb11054.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The kinetics of binding and processing of epidermal growth factor (EGF) was studied in freshly isolated rat hepatocytes. After isolation the hepatocytes had a nonhomogeneous population of surface EGF receptors consisting of approximately 9000 high-affinity sites (Kd 21 pM) and 165,000 low-affinity sites (Kd 0.62 nM). Incubation at 37 degrees C (45 min) increased the number of surface receptors per cell to about 260,000. This increase was selective for the low-affinity receptors and was cycloheximide-sensitive. During 5 h of incubation at 37 degrees C the hepatocytes internalized 6-7-times more EGF molecules than the number of cell surface receptors, based on clearance measurements. The uptake was unaffected by cycloheximide. Concomitant estimation, using acid/salt elution, of surface-bound EGF and internalized EGF showed that the number of internalized EGF molecules exceeded the decrease in surface-binding 6 times. The ratio between internalized EGF and the decrease in surface binding was temperature-dependent, being reduced to a one-to-one stoichiometry at 10 degrees C. After down-regulation (approximately equal to 75%) induced by 5 nM unlabeled EGF the surface EGF receptors did not recover during subsequent incubation (2 h) at 37 degrees C. However, the remaining surface receptors internalized EGF in ninefold excess of their number. The large discrepancy between internalization capacity and cell surface binding capacity was also found in the presence of cycloheximide. The results support the idea that internalized EGF receptors are partly replaced by externalization of preformed intracellular receptors during EGF uptake in isolated hepatocytes, involving recycling of a small population of EGF receptors and/or recruitment of unexposed, pre-existing receptors.
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40
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Malt RA, Chester JF, Gaissert HA, Ross JS. Augmentation of chemically induced pancreatic and bronchial cancers by epidermal growth factor. Gut 1987; 28 Suppl:249-51. [PMID: 3319811 PMCID: PMC1434533 DOI: 10.1136/gut.28.suppl.249] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The incidence of Syrian golden hamsters with pancreatic cancer induced by subcutaneous injections of N-nitroso-bis(2-oxopropyl)amine for 19 weeks (each 10 mg/kg) increased from 44% to 75% (p=0.016) when epidermal growth factor was also administered from week 5 through week 8 (5 mug energy three days for injections). Epidermal growth factor increased pancreatic weight and body weight. The incidence of animals with bronchial cancer doubled. Epidermal growth factor could be a cocarcinogen as a result of its mitogenic activity.
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Affiliation(s)
- R A Malt
- Surgical Services, Shriners Burns Institute, Mass
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Cooper JL, Selinfreund R, Wakshull E, Wharton W. Interaction between monensin and lysosomotropic amines in the regulation of the processing of epidermal growth factor by BALB/c 3T3 cells. Mol Cell Biochem 1987; 73:1-9. [PMID: 3492666 DOI: 10.1007/bf00229370] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Monensin, like the lysosomotropic amines chloroquine and methylamine, caused a large accumulation of 125I-EGF in BALB/c-3T3 cells that was due to specific increases in the amount of intracellular intact hormone. However using a pulse-chase paradigm of 125I-EGF accumulation, marked differences were observed between monensin and the amines. When EGF was accumulated in the presence of monensin, there was a gradual loss of cell-bound radioactivity during a chase in the absence of the drug, and the labeled material recovered in the medium primarily consisted of degraded hormone. The continued presence of monensin in the chase medium substantively prevented the loss of cell bound material, and what little was recovered in the medium consisted of intact 125I-EGF. In contrast, when 125I-EGF was accumulated in the presence of methylamine, predominantly intact peptide was lost from the cells at a relatively high rate during the chase whether or not methylamine remained in the medium. When monensin was present in the chase medium following accumulation in the presence of either chloroquine or methylamine, the loss of intracellular 125I-EGF was essentially blocked.
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Selinfreund R, Lin PH, Cooper JL, Wharton W. Effects of phenothiazines on binding and processing of epidermal growth factor in 3T3 cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1986; 251:C904-11. [PMID: 3491545 DOI: 10.1152/ajpcell.1986.251.6.c904] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Chlorpromazine (CPZ) or the functionally related N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide caused a rapid decrease in binding of 125I-epidermal growth factor (EGF) that was due to a specific decrease in receptor affinity. The decrease in ligand binding was observed when cells were exposed to CPZ at either 4 degrees C or 37 degrees C but a rapid reversal of CPZs effects was observed only during a 37 degrees C incubation. In contrast to the decrease in 125I-EGF binding seen after short (30 min) accumulations at 37 degrees C, the presence of CPZ caused a large increase in the amount of cell-associated radioactivity after longer periods (over 1 h) of accumulation. Although the CPZ-induced effect was similar in extent to that observed after the addition of methylamine, the increased accumulation after CPZ was probably not due to a nonspecific ionic neutralization of the lysosomes. CPZ did not lower EGF binding in cultures chronically treated with a phorbol ester to reduce protein kinase C levels, although the CPZ-induced increases in accumulation were still observed in cells with reduced protein kinase C activity.
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