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Epidermal Growth Factor (epidermal + growth_factor)

Distribution by Scientific Domains
Medical Sciences54%
Life Sciences40%
Chemistry5%
Distribution within Medical Sciences
Oncology & Radiotherapy14%
Periodontology11%
Dermatology3%
25 Other Subdomains57%

Terms modified by Epidermal Growth Factor

  • epidermal growth factor receptor
  • epidermal growth factor receptor expression
    		•
  • epidermal growth factor receptor gene
  • epidermal growth factor receptor inhibitor
    		•
  • epidermal growth factor receptor mutation
  • epidermal growth factor receptor tyrosine kinase
    		•
  • epidermal growth factor receptor tyrosine kinase inhibitor

    • Selected Abstracts

    Epidermal Growth Factor Regulates Amino Acid Transport in Chick Embryo Hepatocytes via Protein Kinase C

    EXPERIMENTAL PHYSIOLOGY, Issue 4 2000
    Maria Marino
    System A-mediated amino acid transport, activation of different steps of signal transduction and involvement of different isoforms of protein kinase C (PKC) have been investigated in chick embryo hepatocytes after epidermal growth factor (EGF) stimulation. EGF rapidly (10 min) increased the rate of aminoisobutyric acid (AIB) uptake in chick embryo hepatocytes freshly isolated on the 19th day of embryonic life, while no change was detectable at other embryonal stages. The growth factor stimulation was abolished by PKC and tyrosine kinase inhibitors and was mimicked by 4-phorbol-12-myristate-13-acetate, dimethyl-2 (PMA). EGF treatment did not modify the phosphorylation of the , isoform of phospholipase C (PLC-,), and inositol trisphosphate (IP3) and intracellular calcium levels, but it induced an increase in PKC activity. Our data show that EGF regulates amino acid uptake, via PKC and without PLC-, activation, only in the last period of chick embryo hepatocyte development. The effects of growth factor on PKC activity suggest the involvement of PKC-, and -, isoforms in EGF modulation of amino acid transport. [source]

    The effect of various concentrations of human recombinant epidermal growth factor on split-thickness skin wounds

    INTERNATIONAL WOUND JOURNAL, Issue 2 2006
    Article first published online: 19 JUN 200
    Effet de concentrations variées de facteur de croissance épidermique recombinant sur les plaies cutanées d'épaisseur partielle Le facteur de croissance épidermique (EGF) est un stimulant puissant de l'épithélialisation. Cependant, l'application topique d'EGF pour aider ŕ la réépithélialisation des plaies d'épaisseur partielle reste sujette ŕ controversies. Un total de 10 porcs, chacun soumis ŕ une plaie dd'épaisseur partielle de 4 cm/4 cm ont été traités 2 fois par jour pendant 10 jours pour étudier les effets de l'EGF humain recombinant avec des concentrations de 0,1, 1, 5, 10, 20 ,g/g, l'excipient seul et deux groupes contrôles. Les plaies des groupes contrôles et de l'excipient seul ont obtenu un temps de cicatrisation ŕ 100%(HT100) de 9·31 ± 1·34 et 8·5 ± 1·12 alors que les plaies traitées par la crčme ŕ l'EGF en concentration ŕ 0·1 ,g/g (HT100 6·40·71), 1 ,g/g (HT100 5·2 ± 0·63), 5 ,g/g (HT100 5·8 ± 0·85), 10 ug/g (HT100: 7·1 ± 1·45), et 25 ug/g (HT100: 7·4 ± 0·57) ont démontré des reductions de temps d'épithélialisation significatives. Parmi les plaies traitées par EGF, les plaies traitées avec des concentrations de 1 et 5 ,g/g obtenaient les épithélialisations les plus rapides et démontraient une augmentation substantielle d'activité des kératinocytes de la couche basale observée par activié Ki-67. En conclusion, Cette etude démontre l'efficacité du facteur de croissance épidermique humain recombinant dans la réépithélialisation des plaies cutanées d'épaisseur partielle, l'effet étant maximum avec des concentrations en EGF de 1 et 5 ,g/g. Einfluß unterschiedlicher humaner rekombinanter epidermaler Wachstumsfaktoren auf intradermale Wunden Epidermal Growth Factor (EGF) ist ein potentes Stimulans für die Epithelialisierung. Es wird jedoch kontrovers diskutiert, ob die topische Applikation von EGF in interadermalen Wunden eine beschleunigte Wundheilung erzielt. 10 Schweine, die jeweils eine 4 × 4 cm intradermale Wunde erhielten, wurden zweimal täglich mit hr-EGF in den Konzentrationen 0,1, 1, 5, 10 und 25 ug über einen Zeitraum von 10 Tagen behandelt. Eine Wunde wurde lediglich mit dem Vehikel, eine weitere als Kontrollwunde behandelt. Diese beiden Wunden erreichten eine 10% Heilung (HT100) nach 9·31 ± 1·34 and 8·5 ± 1·12 Tagen. Dagegen zeigten die Wunden, die mit 0,1 ug HT100: 6·4 ± 0·71), 1 ug/g (HT100: 5·2 ± 0·63), 5 ug/g (HT100: 5·8 ± 0·85), 10 ug/g (HT100: 7·1 ± 1·45), and 25 ug/g (HT100: 7·4 ± 0·57) eine signifikant verkürzte Heilungsdauer. Innerhalb dieser unteschiedlichen Konzentrationen erwiesen sich die Konzentrationen 1 und 5 ug/g als am effektivsten, was durch die Ki-67 Aktivität gezeigt wurde. Zusammenfassend konnte gezeigt werden, dass der hr-EGF eine effektive Substanz für die Heilung von kutanen Wunden ist mit der höchsten Effektivität bei 1 und 5 ug/g. L'effetto di varie concentrazioni di fattore di crescita umano epidermico ricombinante su ulcere cutanee a spessore parziale Il fattore di crescita epidermico (EGF)č un potente stimolatore della riepitelizzazione. Tuttavia l'applicazione topica di EGF per ottenere una migliore riepitelizzazione in lesioni a spessore parziale č molto controversa. Sono stati trattati un totale di 10 maiali, ognuno con lesioni a spessore parziale di 4 × 4 cm, due volte al giorno per 10 giorni per osservare l'effetto del fattore umano ricombinante EGF in concentrazioni di 0·1, 1, 5, 10, 25 ug/g, del solo veicolo, in due controlli. Le ulcere controllo ed il veicolo hanno mostrato ciascuna un 100% di tempo di guarigione (HT100) di 9·31 ± 1·34 e 8·5 ± 1·12 mentre le lesioni trattate con EGF in unguento a concentrazione di 0·1 ug/g (HT100: 6·4 ± 0·71), 1 ug/g (HT100: 5·2 ± 0·63), 5 ug/g (HT100: 5·8 ± 0·85). 10 ug/g (HT100: 7·1 ± 1·45), e 25 ug/g (HT100: 7·4 ± 0·57) hanno mostrato una significativa riduzione del tempo di guarigione. Tra le lesioni trattate con EGF, le lesioni trattate con concentrazioni di EGF di 1 e 5 ug/g hanno ottenuto la piů veloce riepitelizzazione con evidenza di un sostanziale incremento nella attivitŕ dei cheratinociti basali osservata attraverso l'attivitŕ del Ki-67. In conclusione, questo report dimostra l'efficacia del fattore di crescita umano ricombinante epidermico nel favorire la riepitelizzazione di lesioni a spessore parziale con la migliore applicazione di EGF alle concentrazioni di 1 e 5 ug/g. Efecto de diversas concentraciones del factor de crecimiento epidérmico recombinante humano sobre heridas cutáneas de espesor parcial El factor de crecimiento epidérmico (FCE) es un potente estimulante de la epitelización. No obstante, subsiste un debate sobre la aplicación tópica del FCE para facilitar la reepitelización en heridas de espesor parcial. Se trató a un total de diez cerdos, cada uno con ocho heridas de espesor parcial de 4 × 4 cm, dos veces al día durante 10 días para observar el efecto del FCE recombinante humano a concentraciones de 0,1, 1, 5, 10, 25 ,g/g, el vehículo solo y dos controles. Las heridas de control y las tratadas exclusivamente con el vehículo presentaron un tiempo de curación del 100%(TC100) de 9,31 ± 1,34 y 8,5 ± 1,12, mientras que las heridas tratadas con la pomada de FCE a concentraciones de 0,1 ,g/g (TC100: 6,4 ± 0,71), 1 ,g/g (TC100: 5,2 ± 0,63), 5 ,g/g (TC100: 5,8 ± 0,85), 10 ,g/g (TC100: 7,1 ± 1,45) y 25 ,g/g (TC100: 7,4 ± 0,57) mostraron una reducción significativa del tiempo necesario para conseguir la reepitelización. De las heridas tratadas con FCE, en las que recibieron las concentraciones de 1 y 5 ,g/g se logró una reepitelización más rápida con, signos de incremento considerable de la actividad basal de los queratinocitos observada por medio de la actividad Ki-67. En conclusión, este trabajo demuestra la eficacia del factor de crecimiento epidérmico recombinante humano en facilitar la reepitelización de heridas de espesor parcial, y que la curación más eficiente se obtiene con concentraciones de FCE de 1 y 5 ,g/g. Effekten av varierande koncentrationer av human rekombinant epidermal tillväxtfaktor pĺ delhudssĺr Epidermala tillväxtfaktorn (EGF)är en potent stimulant av epitelialisering. Topisk applicering av EGF för att befrämja re-epitelialisering av delhudssĺr har emellertid varit kontroversiellt. Totalt 10 grisar, alla med ĺtta 4 × 4 cm delhudssĺr, behandlades tvĺ gĺnger dagligen under 10 dagar för att observera effekten av "human recombinant EGF" i koncentrationer av 0·1, 1, 5, 10, 25 ug/g, vehikel enbart, och tvĺ kontroller. Vart och ett av kontroll och vehikel enbart sĺren uppvisade 100% läkningstid (HT100) pĺ 9·31 ± 1·34 och 8·5 ± 1·12, medan de sĺr som behandlades med EGF salva med en koncentration av 0·1 ug/g (HT100: 6·4 ± 0·71), 1 ug/g (HT100: 5·2 ± 0·63), 5 ug/g (HT100: 5·8 ± 0·85), 10 ug/g (HT100: 7·1 ± 1·45), och 25 ug/g (HT100: 7·4 ± 0·57) uppvisade signifikant reduktion av tiden för att uppnĺ re-epitelialisering. Bland de EGF behandlade sĺren, uppnĺdde de sĺr som behandlats med EGF med en koncentration av 1 och 5 ug/g snabbast re-epitelialisering med bevis för märkbar ökning av basal keratinocyte aktivitet iakktagen genom Ki-67 aktivitet. Sammanfattningsvis uppvisar denna rapport den gynnsamma effekten av human rekombinant EGF i re-epitelialisering av delhuds sĺr. Den gynnsammaste läkningseffekten iakktogs med EGF i koncentrationer av 1 och 5 ug/g. [source]

    In vitro differentiation of human mesenchymal stem cells to epithelial lineage

    JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 3 2007
    Virgil P, unescu
    Abstract Our study examined whether human bone marrow-derived MSCs are able to differentiate, in vitro, into functional epithelial-like cells. MSCs were isolated from the sternum of 8 patients with different hematological disorders. The surface phenotype of these cells was characterized. To induce epithelial differentiation, MSCs were cultured using Epidermal Growth Factor, Keratinocyte Growth Factor, Hepatocyte Growth Factor and Insulin-like growth Factor-II. Differentiated cells were further characterized both morphologically and functionally by their capacity to express markers with specificity for epithelial lineage. The expression of cytokeratin 19 was assessed by immunocytochemistry, and cytokeratin 18 was evaluated by quantitative RT-PCR (Taq-man). The data demonstrate that human MSCs isolated from human bone marrow can differentiate into epithelial-like cells and may thus serve as a cell source for tissue engineering and cell therapy of epithelial tissue. [source]

    Epidermal Growth Factor Induces Oxidative Neuronal Injury in Cortical Culture

    JOURNAL OF NEUROCHEMISTRY, Issue 1 2000
    Yoo Kyung Cha
    Abstract : Recently, we have demonstrated that certain neurotrophic factors can induce oxidative neuronal necrosis by acting at the cognate tyrosine kinase-linked receptors. Epidermal growth factor (EGF) has neurotrophic effects via the tyrosine kinase-linked EGF receptor (EGFR), but its neurotoxic potential has not been studied. Here, we examined this possibility in mouse cortical culture. Exposure of cortical cultures to 1-100 ng/ml EGF induced gradually developing neuronal death, which was complete in 48-72 h ; no injury to astrocytes was noted. Electron microscopic findings of EGF-induced neuronal death were consistent with necrosis ; severe mitochondrial swelling and disruption of cytoplasmic membrane occurred, whereas nuclei appeared relatively intact. The EGF-induced neuronal death was accompanied by increased free radical generation and blocked by the anti-oxidant Trolox. Suggesting mediation by the EGFR, an EGFR tyrosine kinase-specific inhibitor, C56, attenuated EGF-induced neuronal death. In addition, inhibitors of extracellular signal-regulated protein kinase 1/2 (Erk-1/2) (PD98056), protein kinase A (H89), and protein kinase C (GF109203X) blocked EGF-induced neuronal death. A p38 mitogen-activated protein kinase inhibitor (SB203580) or glutamate antagonists (MK-801 and 6-cyano-7-nitroquinoxaline-2,3-dione) showed no protective effect. The present results suggest that prolonged activation of the EGFR may trigger oxidative neuronal injury in central neurons. [source]

    Effects of Epidermal Growth Factor on Fibroblast Migration through Biomimetic Hydrogels

    BIOTECHNOLOGY PROGRESS, Issue 6 2003
    Andrea S. Gobin
    We have previously reported on the development and use of synthetic hydrogel extracellular matrix (ECM) analogues that can be used to study the mechanisms of migration. These biomimetic hydrogels consist of bioinert poly(ethylene glycol) diacrylate derivatives with proteolytically degradable peptide sequences included in the backbone of the polymer and adhesion peptide sequences grafted into the network. Cells adhere to the hydrogel via interaction between the grafted adhesion ligands and receptors on the cell surface. The cells migrate through the three-dimensional system by secreting the appropriate proteolytic enzymes, which are involved in cell migration and are targeted to the peptide sequences incorporated in the backbone of the polymer. It was observed that cell migration has a biphasic dependence on adhesion ligand concentration, with optimal migration at intermediate ligand levels. In this study, we demonstrate that we can covalently attach epidermal growth factor (EGF) to PEG and graft them into the hydrogels. It was observed that EGF when tethered maintained mitogenic activity. It was also observed that fibroblast migration significantly increased in the presence of the grafted EGF through the collagenase-sensitive hydrogels. In addition, the increase in migration was found to be independent from the proliferative response of the cells. These synthetic ECM analogues allow one to systematically control identities and concentrations of biomolecules and are useful tools to study mechanisms of cell migration. [source]

    Keratinocyte growth factor and scatter factor expression by regionally defined oral fibroblasts

    EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2003
    Scott Thomas William McKeown
    Keratinocyte growth factor (KGF) and hepatocyte growth factor/scatter factor (SF) are two signalling molecules thought to play important roles in regulating epithelial,mesenchymal interactions. Expression of both factors by fibroblasts in subepithelial connective tissue may play a role in maintaining epithelial integrity in health and in the apical migration of junctional epithelium in periodontitis. The aims of this study were (a) to compare expression levels of KGF and SF by periodontal ligament (PDL) and gingival fibroblasts; and (ii) to determine the effects of interleukin (IL)-1,, transforming growth factor (TGF)-,1, platelet-derived growth factor (PDGF)-BB and epidermal growth factor (EGF) on KGF/SF expression by these cell populations. Three paired PDL and gingival fibroblast strains were developed. The KGF and SF protein levels were analysed by enzyme-linked immunosorbent assay. Relative levels of KGF and SF mRNA in cytokine-treated cultures were determined using semiquantitative reverse transcriptase polymerase chain reaction. No differences in the levels of KGF and SF produced by PDL and gingival (SOG) populations were found. In both cell types IL-1, stimulated KGF and SF expression, while TGF-,1 significantly inhibited expression at both the mRNA and protein levels. Epidermal growth factor and PDGF-BB induced differing effects on expression, stimulating SF protein production but inhibiting KGF output in both fibroblast populations. Differences in response to EGF and PDGF were also seen between paired PDL and gingival fibroblasts. [source]

    Vinexin , regulates the phosphorylation of epidermal growth factor receptor on the cell surface

    GENES TO CELLS, Issue 9 2006
    Masaru Mitsushima
    Epidermal growth factor (EGF) regulates various cellular events, including proliferation, differentiation, migration and oncogenesis. In this study, we found that exogenous expression of vinexin , enhanced the phosphorylation of 180-kDa proteins in an EGF-dependent manner in Cos-7 cells. Western blot analysis using phospho-specific antibodies against EGFR identified EGFR as a phosphorylated 180-kDa protein. Vinexin , did not stimulate the phosphorylation of EGFR but suppressed the dephosphorylation, resulting in a sustained phosphorylation. Mutational analyses revealed that both the first and third SH3 domains were required for a sustained phosphorylation of EGFR. Small interfering RNA-mediated knockdown of vinexin , reduced the phosphorylation of EGFR on the cell surface in HeLa cells. The sustained phosphorylation of EGFR induced by vinexin , was completely abolished by adding the EGFR-specific inhibitor AG1478 even after EGF stimulation, suggesting that the kinase activity of EGFR is required for the sustained phosphorylation induced by vinexin ,. We also found that E3 ubiquitin ligase c-Cbl is a binding partner of vinexin , through the third SH3 domain. Expression of wild-type vinexin , but not a mutant containing a mutation in the third SH3 domain decreased the cytosolic pool of c-Cbl and increased the amount of membrane-associated c-Cbl. Furthermore, over-expression of c-Cbl suppressed the sustained phosphorylation of EGFR induced by vinexin ,. These results suggest that vinexin , plays a role in maintaining the phosphorylation of EGFR on the plasma membrane through the regulation of c-Cbl. [source]

    Epidermal growth factor receptor expression regulates proliferation in the postnatal rat retina

    GLIA, Issue 2 2006
    Jennie L. Close
    Abstract Epidermal growth factor (EGF) is known to promote proliferation of both retinal progenitors and Muller glia in vitro, but several questions remain concerning an in vivo role for this factor. In this study, we investigated whether the EGF receptor (EGFR) is necessary for the maintenance of normal levels of progenitor and Muller glial proliferation in vivo. Here, we show that (1) mice with homozygous deletion of the Egfr gene have reduced proliferation in late stages of retinal histogenesis, (2) EGF is mitogenic for Müller glia in vivo during the first two postnatal weeks in the rodent retina, (3) the effectiveness of EGF as a Müller glial mitogen declines in parallel with the decline in EGFR expression as the retina matures, and (4) following damage to the retina from continuous light exposure, EGFR expression is up-regulated in Müller glia to levels close to those in the neonatal retina, resulting in a renewed mitotic response to EGF. Together with previous results from other studies, these data indicate that the downregulation of a growth factor receptor is one mechanism by which glial cells maintain mitotic quiescence in the mature nervous system. © 2006 Wiley-Liss, Inc. [source]

    Immunohistochemical study of epidermal growth factor receptor in adenoid cystic carcinoma of salivary gland origin

    HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 7 2002
    Marilena Vered DMD
    Abstract Background Epidermal growth factor (EGF) and its receptor (EGFR) are involved in the development of salivary gland tumors. Recently, treatment modalities for EGFR inhibition have shown an enhanced clinical response in carcinomas of different locations. Adenoid cystic carcinoma (ACC) of salivary gland origin is a malignant tumor with a poor long-term outcome. If salivary gland ACC does exhibit EGFR, then immunotherapy could have a major impact on improving its prognosis. Methods The study consisted of 34 samples of formalin-fixed, paraffin-embedded specimens of salivary gland ACC. Specimens were stained with a mouse antihuman monoclonal antibody for immunohistochemical detection of EGFR. Overlying oral mucosa and adjacent normal salivary ducts served as internal controls. Both membrane and cytoplasmic staining were evaluated. Staining score was calculated by multiplying the percentage of positively stained tumor cells by the intensity of the staining. The highest score for a given tumor was equal to 2. Results In the final analysis, 27 of the 34 specimens were included; 7 were excluded, because the internal control did not reveal any staining. Of these 27 specimens, 23 (85%) stained positively for EGFR with a staining score of 0.05 to 1.8. Three palatal tumors attained the highest scores (one tumor, 1.2, and the remaining two, 1.8). Conclusions Most salivary gland ACC stained positively for EGFR, and in some the staining was quite intense. On the basis of the already proven antitumoral effect of agents acting as EGFR inhibitors, it is suggested that patients with ACC might benefit from these agents, especially when surgery has failed or in those with recurrent or metastatic disease. © 2002 Wiley Periodicals, Inc. Head Neck 24: 632,636, 2002 [source]

    Regulation of plasminogen activators in human thyroid follicular cells and their relationship to differentiated function

    JOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2007
    Radhika Susarla
    Human thyroid cells in culture take up and organify 125I when cultured in TSH (acting through cAMP) and insulin. They also secrete urokinase (uPA) and tissue-type (tPA) plasminogen activators (5,100 IU/106cells/day). TSH and insulin both decreased secreted PA activity (PAA), uPA and tPA protein and their mRNAs. Autocrine fibroblast growth factor increased secreted PAA and inhibited thyroid cell 125I uptake. Epidermal growth factor (EGF) and the protein kinase C (PKC) activator, TPA significantly increased PAA and inhibited thyroid differentiated function, (TPA,>,EGF). For TPA, effects were rapid, increased PAA secretion and decreased 125I uptake being seen at 4 h whereas for EGF, a 24 h incubation was required. qRT-PCR showed significantly increased mRNA expression of uPA with lesser effects on tPA. Aprotinin, which inhibits PAA, increased 125I uptake but did not abrogate the effects of TPA and EGF. The MEKK inhibitor, PD98059 partially reversed the effects of EGF and TPA on PAA, and largely reversed the effects of EGF but not TPA on differentiated function. PKC inhibitors bisindoylmaleimide 1, and the specific PKC, inhibitor, LY379196 completely reversed the effects of TPA on 125I uptake and PAA whereas EGF effects were unaffected. TPA inhibited follicle formation and this effect was blocked by LY379196 but not PD98059. We conclude that in thyroid cells, MAPK activation inversely correlates with 125I uptake and directly correlates with PA expression, in contrast to the effects of cAMP. TPA effects on iodide metabolism, dissolution of follicles and uPA synthesis are mediated predominantly through PKC, whereas EGF exerts its effects through MAPK but not PKC,. J. Cell. Physiol. 212:643,654, 2007. © 2007 Wiley-Liss, Inc. [source]

    Epidermal growth factor stimulates proton efflux from chondrocytic cells

    JOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2002
    Kevin E.H. Lui
    Proton efflux from chondrocytes alters the extracellular pH and ionic composition of cartilage, and influences the synthesis and degradation of extracellular matrix. Epidermal growth factor (EGF) promotes chondrocyte proliferation during skeletal development and accumulates in the synovial fluid in rheumatoid arthritis. The purpose of this study was to investigate the effect of EGF on proton efflux from chondrocytes. When monitored using a Cytosensor microphysiometer, EGF was found to rapidly activate proton efflux from CFK2 chondrocytic cells and rat articular chondrocytes. The actions of EGF were concentration-dependent with half-maximal effects at 0.3,0.7 ng/ml. Partial desensitization and time-dependent recovery of the response were observed following repeated exposures to EGF. EGF-induced proton efflux was dependent on extracellular glucose, and inhibitors of Na+/H+ exchange (NHE) markedly attenuated the initial increase in proton efflux. The response was diminished by inhibitors of phosphatidylinositol 3-kinase and phospholipase C, but not by inhibitors of MEK (MAPK/ERK kinase) or protein kinase A or C. Thus, EGF-induced proton efflux involves glucose metabolism and NHE, and is regulated by a discrete subset of EGF-activated signaling pathways. In vivo, proton efflux induced by EGF may lead to an acidic environment, enhancing turnover of cartilage matrix during development and in rheumatoid arthritis. © 2002 Wiley-Liss, Inc. [source]

    Influences of dopaminergic lesion on epidermal growth factor-ErbB signals in Parkinson's disease and its model: neurotrophic implication in nigrostriatal neurons

    JOURNAL OF NEUROCHEMISTRY, Issue 4 2005
    Yuriko Iwakura
    Abstract Epidermal growth factor (EGF) is a member of a structurally related family containing heparin-binding EGF-like growth factor (HB-EGF) and transforming growth factor alpha (TGF,) that exerts neurotrophic activity on midbrain dopaminergic neurons. To examine neurotrophic abnormality in Parkinson's disease (PD), we measured the protein content of EGF, TGF,, and HB-EGF in post-mortem brains of patients with Parkinson's disease and age-matched control subjects. Protein levels of EGF and tyrosine hydroxylase were decreased in the prefrontal cortex and the striatum of patients. In contrast, HB-EGF and TGF, levels were not significantly altered in either region. The expression of EGF receptors (ErbB1 and ErbB2, but not ErbB3 or ErbB4) was down-regulated significantly in the same forebrain regions. The same phenomenon was mimicked in rats by dopaminergic lesions induced by nigral 6-hydroxydopamine infusion. EGF and ErbB1 levels in the striatum of the PD model were markedly reduced on the lesioned side, compared with the control hemisphere. Subchronic supplement of EGF in the striatum of the PD model locally prevented the dopaminergic neurodegeration as measured by tyrosine hydroxylase immunoreactivity. These findings suggest that the neurotrophic activity of EGF is maintained by afferent signals of midbrain dopaminergic neurons and is impaired in patients with Parkinson's disease. [source]

    Epidermal Growth Factor Induces Oxidative Neuronal Injury in Cortical Culture

    JOURNAL OF NEUROCHEMISTRY, Issue 1 2000
    Yoo Kyung Cha
    Abstract : Recently, we have demonstrated that certain neurotrophic factors can induce oxidative neuronal necrosis by acting at the cognate tyrosine kinase-linked receptors. Epidermal growth factor (EGF) has neurotrophic effects via the tyrosine kinase-linked EGF receptor (EGFR), but its neurotoxic potential has not been studied. Here, we examined this possibility in mouse cortical culture. Exposure of cortical cultures to 1-100 ng/ml EGF induced gradually developing neuronal death, which was complete in 48-72 h ; no injury to astrocytes was noted. Electron microscopic findings of EGF-induced neuronal death were consistent with necrosis ; severe mitochondrial swelling and disruption of cytoplasmic membrane occurred, whereas nuclei appeared relatively intact. The EGF-induced neuronal death was accompanied by increased free radical generation and blocked by the anti-oxidant Trolox. Suggesting mediation by the EGFR, an EGFR tyrosine kinase-specific inhibitor, C56, attenuated EGF-induced neuronal death. In addition, inhibitors of extracellular signal-regulated protein kinase 1/2 (Erk-1/2) (PD98056), protein kinase A (H89), and protein kinase C (GF109203X) blocked EGF-induced neuronal death. A p38 mitogen-activated protein kinase inhibitor (SB203580) or glutamate antagonists (MK-801 and 6-cyano-7-nitroquinoxaline-2,3-dione) showed no protective effect. The present results suggest that prolonged activation of the EGFR may trigger oxidative neuronal injury in central neurons. [source]

    Epidermal growth factor released from platelet-rich plasma promotes endothelial cell proliferation in vitro

    JOURNAL OF PERIODONTAL RESEARCH, Issue 1 2010
    M.-P. Bertrand-Duchesne
    Bertrand-Duchesne M-P, Grenier D, Gagnon G. Epidermal growth factor released from platelet-rich plasmapromotes endothelial cell proliferation in vitro. J Periodont Res 2009; doi: 10.1111/j.1600-0765.2009.01205.x. © 2009 The Authors. Journal compilation © 2009 Blackwell Munksgaard Background and Objective:, The therapeutic benefits of platelet-rich plasma (PRP) for the promotion of healing and regeneration of periodontal tissues are thought to result from enrichment in growth factors released from platelets. The aim of this study was to evaluate the effects of specific growth factors released from PRP on endothelial cell proliferation. Material and Methods:, The levels of vascular endothelial growth factor (VEGF), platelet-derived growth factor BB (PDGF-BB), basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) in supernatants of calcium- and thrombin-activated PRP samples from five donors were quantified by enzyme-linked immunosorbent assay. Supernatants were treated with neutralizing antibodies specific to each growth factor, and the effects of these treatments on human umbilical vein endothelial cell (HUVEC) proliferation in vitro were determined. The effect of removing EGF from PRP supernatants with antibody-coated beads on HUVEC proliferation was also tested. Results:, Average concentrations of VEGF, PDGF-BB, bFGF and EGF in PRP supernatants were 189, 27,190, 39.5 and 513 pg/mL, respectively. The addition of EGF neutralizing antibodies to the PRP supernatants significantly reduced HUVEC proliferation (up to 40%), while such an inhibition was not observed following neutralization of the other growth factors. Removal of EGF from PRP supernatants by treatment with antibody-coated beads also resulted in a significant decrease in HUVEC proliferation. Recombinant EGF increased HUVEC proliferation in vitro in a dose-dependent manner. Conclusion:, This study showed that PRP supernatants are highly mitogenic for endothelial cells and provided evidence that this effect may be due, at least in part, to the presence of EGF. In vivo experiments are needed to confirm the roles of specific growth factors released from PRP in the healing of oral surgical and/or periodontal wounds. [source]

    Epidermal growth factor stimulates urokinase-type plasminogen activator expression in human gingival fibroblasts.

    JOURNAL OF PERIODONTAL RESEARCH, Issue 6 2004
    Possible modulation by genistein, curcumin
    Background:, Regulation of the extracellular matrix turnover is a crucial process in wound healing and the progress of periodontal disease. It has been proposed that urokinase-type plasminogen activator (uPA), under the control of growth factors or cytokines, provides the proteolytic potential to the accomplishment of these cellular events. Epidermal growth factor (EGF) is one of the growth factors that has been shown to be active in uPA regulation. Methods:, In this study, we have assessed the effect of EGF on uPA expression in primary cultures of human gingival fibroblasts. We also studied the signaling pathways involved in this process and the role of the dietary phytoestrogens curcumin and genistein as potential modulators of this response. Results:, Human gingival fibroblasts expressed a basal uPA activity, which was inhibited by genistein, but not by curcumin. After treatment with 10 ng/ml EGF, uPA production was strongly stimulated. Exposure to genistein and curcumin inhibited EGF-stimulated urokinase production, although only genistein showed a statistically significant inhibitory response. Using more specific inhibitors, we found that the mitogen-activated extracellular kinase and c-Jun N-terminal kinase (JNK) inhibitors PD98059 and SP600125 also blocked the EGF-dependent stimulatory effect. On the other hand, SB203580, inhibitor of the p38 member of mitogen-activated protein kinase family, did not alter this response. In accordance to these findings, EGF stimulated a potent activation of JNK and a mild activation of extracellular signal-regulated kinases 1/2. Finally, EGF stimulated the phosphorylation of its receptor and tyrphostin (AG1478), curcumin and genistein were able to inhibit this stimulatory effect. Conclusions:, These results indicate that EGF constitutes a strong stimuli on uPA expression in human gingival fibroblasts. Our data also shows that EGF-stimulated uPA production involves the activation of the extracellular signal-regulated kinases 1/2 and JNK signaling pathways and might be modulated by the natural phytoestrogens curcumin and genistein. [source]

    Inositol hexaphosphate downregulates both constitutive and ligand-induced mitogenic and cell survival signaling, and causes caspase-mediated apoptotic death of human prostate carcinoma PC-3 cells,

    MOLECULAR CARCINOGENESIS, Issue 1 2010
    Mallikarjuna Gu
    Abstract Constitutively active mitogenic and prosurvival signaling cascades due to aberrant expression and interaction of growth factors and their receptors are well documented in human prostate cancer (PCa). Epidermal growth factor (EGF) and insulin-like growth factor-1 (IGF-1) are potent mitogens that regulate proliferation and survival of PCa cells via autocrine and paracrine loops involving both mitogen-activated protein kinase (MAPK)- and Akt-mediated signaling. Accordingly, here we assessed the effect of inositol hexaphosphate (IP6) on constitutive and ligand (EGF and IGF-1)-induced biological responses and associated signaling cascades in advanced and androgen-independent human PCa PC-3 cells. Treatment of PC-3 cells with 2,mM IP6 strongly inhibited both growth and proliferation and decreased cell viability; similar effects were also observed in other human PCa DU145 and LNCaP cells. IP6 also caused a strong apoptotic death of PC-3 cells together with caspase 3 and PARP cleavage. Mechanistic studies showed that biological effects of IP6 were associated with inhibition of both constitutive and ligand-induced Akt phosphorylation together with a decrease in total Akt levels, but a differential inhibitory effect on MAPKs extra cellular signal-regulated kinase 1/2 (ERK1/2), c- Jun N-terminal protein kinase (JNK1/2), and p38 under constitutive and ligand-activated conditions. Under similar condition, IP6 also inhibited AP-1 DNA-binding activity and decreased nuclear levels of both phospho and total c-Fos and c- Jun. Together, these findings for the first time establish IP6 efficacy in inhibiting aberrant EGF receptor (EGFR) or IGF-1 receptor (IGF-1R) pathway-mediated sustained growth promoting and survival signaling cascades in advanced and androgen-independent human PCa PC-3 cells, which might have translational implications in advanced human PCa control and management. © 2009 Wiley-Liss, Inc. [source]

    Epidermal growth factor receptor and claudin-2 participate in A549 permeability and remodeling: Implications for non-small cell lung cancer tumor colonization

    MOLECULAR CARCINOGENESIS, Issue 6 2009
    Yakov Peter
    Abstract Tumor colonization involves changes in cell permeability and remodeling. Paracellular permeability is regulated by claudins, integrated tight junction (TJ) proteins, located on the apicolateral portion of epithelial cells. Epidermal growth factor (EGF) was reported to modify cellular claudin levels and induce remodeling. To investigate a role for EGF receptor (EGFR) activation in tumor colonization we studied the effect of EGF and claudin-2 overexpression on permeability and cell reorganization in the human A549 non-small cell lung cancer (NSCLC) cell line. Our data demonstrated that A549 cells possess functional TJs and that EGF treatment increased levels of claudin-2 expression by 46%. Furthermore, EGFR signaling reduced monolayer permeability to choline and triggered cellular remodeling. The mitogen-activated protein kinase inhibitor PD98059 blocked the effect on A549 permeability and remodeling. EGF stimulation also exacerbated a fourfold increase in cell colonization elicited by claudin-2 upregulation. Our findings are consistent with the hypothesis that EGFR signaling plays an important role in A549 cell physiology and acts synergistically with claudin-2 to accelerate tumor colonization. Understanding the influence of EGF on A549 cell permeability and reorganization will help shed light on NSCLC tumor colonization and contribute to the development of novel anti-cancer treatments. © 2008 Wiley-Liss, Inc. [source]

    Acquisition of apoptotic resistance in cadmium-induced malignant transformation: Specific perturbation of JNK signal transduction pathway and associated metallothionein overexpression,

    MOLECULAR CARCINOGENESIS, Issue 8 2006
    Wei Qu
    Abstract Prior work has shown that chronic cadmium exposed rat liver epithelial cells (CCE-LE) become malignantly transformed after protracted low level cadmium exposure. Acquisition of apoptotic resistance is common in oncogenesis and the present work explores this possibility in CCE-LE cells. CCE-LE cells were resistant to apoptosis induced by etoposide or an acute high concentration of cadmium as assessed by flow cytometry with annexin/FITC. Three key mitogen-activated protein kinases (MAPKs), namely ERK1/2, JNK1/2, and p38, were phosphorylated in CCE-LE cells after acute cadmium exposure. However, the levels of phosphorylated JNK1/2 were markedly decreased in CCE-LE cells compared to control. JNK kinase activity was also suppressed in CCE-LE cells exposed to cadmium. Epidermal growth factor (EGF), used as a positive control for stimulating JNK phosphorylation, was much less effective in CCE-LE cells than control cells. Ro318220 (Ro), a strong activator of JNK, increased phosphorylated JNK1/2 to levels similar to the cadmium-treated control cells and also enhanced apoptosis in response to cadmium in CCE-LE cells. Metallothionein (MT), which is thought to potentially inhibit apoptosis, was strongly overexpressed in CCE-LE cells. Further, in MT knockout (MT,/,) fibroblasts, JNK1/2 phosphorylation was markedly increased after cadmium exposure compared with similarly treated wild-type (MT+/+) cells. These results indicate cadmium-transformed cells acquired apoptotic resistance, which may be linked to the specific suppression of the JNK pathway and is associated with MT overexpression, which, in turn, may impact this signal transduction pathway. The acquisition of apoptotic resistance may play an important role in cadmium carcinogenesis by contributing to both tumor initiation and malignant progression. Published 2006 Wiley-Liss, Inc. [source]

    Epidermal growth factor (EGF) induces motility and upregulates MMP-9 and TIMP-1 in bovine trophoblast cells

    MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 7 2010
    M. Dilly
    Differentiation and restricted invasion/migration of trophoblast cells are crucial for feto-maternal communication in the synepitheliochorial placenta of cattle. EGF is expressed in the bovine placenta and likely regulates these cell properties. As cell migration and motility rely on the degradation of extracellular matrix we hypothesize that EGF is involved in the regulation of the MMP-9/TIMP-1 balance and thus could influence trophoblast migration, tissue remodeling, and the release of the fetal membranes after parturition. The aim of this in vitro study was to examine EGF-mediated effects on cell motility, proliferation, and MMP-9 and TIMP-1 expression in cultured bovine trophoblast cells. We used a trophoblast cell line (F3) derived from bovine placentomes to examine the influence of EGF on MMP-9 and TIMP-1 expression by semiquantitative RT-PCR and MMP activity by zymography. Migration assays were performed using a Boyden chamber and cell motility was measured by time-lapse analyses. To identify the involved signaling cascades, phosphorylation of mitogen-activated protein kinase (MAPK) 42/44 and Akt was detected by Western blot. EGF treatment increased both the abundance of MMP-9 and TIMP-1 mRNAs and the proteolytic activity of MMP-9. Furthermore, EGF stimulated proliferation and migration of F3 cells. Addition of specific inhibitors of MAPK (PD98059) and/or PI3K (LY294002) activation abolished or reduced EGF-induced effects in all experiments. In conclusion, EGF-mediated effects stimulate migration and proliferation of bovine trophoblast cells and may be involved in bovine placental tissue remodeling and postpartum release of fetal membranes. Mol. Reprod. Dev. 77: 622,629, 2010. © 2010 Wiley-Liss, Inc. [source]

    Signal transduction responses to lysophosphatidic acid and sphingosine 1-phosphate in human prostate cancer cells

    THE PROSTATE, Issue 14 2009
    Terra C. Gibbs
    Abstract BACKGROUND Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are lipid mediators that bind to G-protein-coupled receptors. In this study, signaling responses to 18:1 LPA and S1P were examined in parallel in three human prostate cancer cell lines: PC-3, Du145, and LNCaP. METHODS Receptor expression was assessed by RT-PCR, Northern blotting, and immunoblotting. Cellular responses to mediators were studied by proliferation assays, phosphoprotein immunoblotting, and phospholipid metabolism assays. RESULTS All cell lines express mRNA for both LPA and S1P receptors. PC-3 and Du145, but not LNCaP, proliferate in response to LPA and S1P. Epidermal growth factor (EGF), phorbol 12-myristate 13-acetate (PMA), LPA, and S1P induce activation of Erks in PC-3 and Du145; only EGF and PMA activate Erks in LNCaP. In Du145 and PC-3, Akt is activated by EGF, LPA, and S1P. Akt is constitutively active in LNCaP; EGF but not LPA or S1P stimulates further phosphorylation. FAK is phosphorylated in response to both LPA and S1P in PC-3 and Du145, but not in LNCaP. LPA and S1P stimulate phospholipase D (PLD) activity to varying extents in the different cell lines. Notably, both lipid mediators activate PLD in LNCaP. In Du145, LPA, but not S1P, activates PLD and enhances cellular production of LPA. CONCLUSIONS Although both LPA and S1P induce signal transduction in all prostate cancer cell lines studied, a proliferation response is observed only when the Erk, Akt, and FAK pathways are activated. Other responses to the lipid mediators, such as PLD activation, likely contribute to other cellular outcomes. Prostate 69: 1493,1506, 2009. © 2009 Wiley-Liss, Inc. [source]

    Perinatal development of the rat kidney: Apoptosis and epidermal growth factor

    CONGENITAL ANOMALIES, Issue 3 2003
    Toshiya Okada
    ABSTRACT, Localization of apoptotic cells in the kidney of perinatal rats was examined by the terminal deoxynucleotidyl transferase,mediated d,UTP,biotin nick end labeling (TUNEL) method and electron microscopy. Perinatal changes in the percentage of kidney cells with DNA fragmentation were determined by flow cytometric analysis. Through observation of two successive sections, the relationship between the localization of the epidermal growth factor receptor (EGFR) positive cells and TUNEL positive cells in the kidney was determined. From fetal day 18 to neonatal day 5, TUNEL positive cells were noted in immature glomeruli, collecting ducts and interstitium. Electron microscopically, chromatin condensed nuclei and apoptotic bodies were seen in the same tissue component as the TUNEL positive cells. The percentage of DNA fragmented cells significantly increased from fetal days 18 to 20 and significantly decreased from fetal days 20 to 22, while they still remained low in the neonatal period. The TUNEL positive cells in immature glomeruli and collecting ducts were not reactive to the EGFR antibody. The TUNEL positive cells were not observed in the proximal tubular cells, which were positive to EGFR antibody. These results indicate that apoptotic cells are present in the kidney throughout the perinatal period in the rat and that EGF plays an important role in perinatal development of the rat kidney. [source]

    Nucleotides and epidermal growth factor induce parallel cytoskeletal rearrangements and migration in cultured adult murine neural stem cells

    ACTA PHYSIOLOGICA, Issue 2 2010
    I. Grimm
    Abstract Aim:, The adult subventricular zone (SVZ) contains neural stem cells that generate neuroblasts migrating to the olfactory bulb (OB) and differentiating into interneurones. The molecular cues controlling essential functions within the neurogenesis pathway such as proliferation, short and long distance migration, functional integration and cell survival are poorly understood. We have previously shown that cultured adult neural stem cells express a considerable variety of nucleotide receptors and that nucleotides and epidermal growth factor (EGF) induce converging intracellular signalling pathways that carry potential for synergism in the control of neural stem cell proliferation and cell survival. Here we investigate the role of EGF and the nucleotides ATP, ADP,S and UTP in neural stem cell migration. Methods:, Neural stem cells were prepared from adult mice and subjected to adherent culture. Labelling of F-actin was performed with tetramethylrhodamine isothiocyanate-phalloidin. Images were processed for quantitative evaluation of fluorescence labelling. Agonist-induced phosphorylation of AKT and focal adhesion kinase was analysed by quantitative Western blotting. Agonist-dependent cell migration was assayed using 48-well microchemotaxis chambers. Results:, Nucleotides and EGF induce the formation of stress fibres, an increase in the cortical actin cytoskeleton and in cell spreading. This is associated with increased phosphorylation of AKT and focal adhesion kinase. Using microchemotaxis chambers we demonstrate a parallel increase in cell migration. Conclusion:, Our results suggest that nucleotides and EGF acting as paracrine or autocrine signalling substances can be of relevance for structuring and maintaining the cytoarchitecture of the SVZ and the stream of neuroblasts migrating to the OB. [source]

    Measurement of barbed ends, actin polymerization, and motility in live carcinoma cells after growth factor stimulation,

    CYTOSKELETON, Issue 4 2004
    Mike Lorenz
    Abstract Motility is associated with the ability to extend F-actin-rich protrusions and depends on free barbed ends as new actin polymerization sites. To understand the function and regulation of different proteins involved in the process of generating barbed ends, e.g., cofilin and Arp2/3, fixed cell approaches have been used to determine the relative barbed end concentration in cells. The major disadvantages of these approaches are permeabilization and fixation of cells. In this work, we describe a new live-cell time-lapse microscopy assay to determine the increase of barbed ends after cell stimulation that does not use permeabilization and provides a better time resolution. We established a metastatic carcinoma cell line (MTLn3) stably expressing GFP-,-actin at physiological levels. Stimulation of MTLn3 cells with epidermal growth factor (EGF) causes rapid and transient lamellipod protrusion along with an increase in actin polymerization at the leading edge, which can be followed in live cell experiments. By measuring the increase of F-actin at the leading edge vs. time, we were able to determine the relative increase of barbed ends after stimulation with a high temporal resolution. The F-actin as well as the barbed end concentration agrees well with published data for this cell line. Using this newly developed assay, a decrease in lamellipod extension and a large reduction of barbed ends was documented after microinjecting an anti-cofilin function blocking antibody. This assay has a high potential for applications where rapid changes in the dynamic filament population are to be measured. Cell Motil. Cytoskeleton 57:207,217, 2004. © 2004 Wiley-Liss, Inc. [source]

    Sustained MAPK activation is dependent on continual NGF receptor regeneration

    DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 5 2004
    Dongru Qiu
    It still remains intriguing how signal specificity is achieved when different signals are relayed by the common intracellular signal transduction pathways. A well documented example for signal specificity determination is found in rat phaeochromocytoma PC12 cells where epidermal growth factor (EGF) stimulation produces a transient mitogen-activated protein kinase (MAPK) activation and leads to cell proliferation while nerve growth factor (NGF) initiates a sustained MAPK activation and induces cell differentiation. In this simulation, we demonstrated that NGF-induced sustained MAPK activation may mainly depend on continual regeneration of NGF receptors and that the presence of a small pool of surface receptors is enough to maintain a sustained MAPK activation. On the other hand, MAPK activation is not significantly sensitive to the half-life of internalized receptors and the levels of NGF-specific MAPK phosphatase MAP kinase phosphatase-3 (MKP-3), though cytoplasmic persistence of internalized NGF-bound receptors and the MKP-3 dependent feedback control also contribute to the sustaining of MAPK activation. These results are consistent with the recent experimental evidence that persistent tyrosine receptor kinase A (TrkA) activity is necessary to maintain transcription in the differentiating PC12 cells (Chang et al. 2003) and a sustained Src kinase activity is detected in response to NGF stimulation (Gatti 2003). It is suggested that sustained or transient MAPK activation induced by different growth factor and neurotrophins, which is crucial to their signaling specificity, could be satisfactorily accounted for by their specific receptor turnover kinetics rather than by the activation of specific downstream signaling cascades. [source]

    Opposing effects on TSC-22 expression by BMP and receptor tyrosine kinase signals in the developing feather tract

    DEVELOPMENTAL DYNAMICS, Issue 1 2002
    Cord E. Dohrmann
    Abstract TSC-22 (transforming growth factor-,,stimulated clone 22) belongs to a family of leucine zipper transcription factors that includes sequences from invertebrates and vertebrates. The single Drosophila family member, encoded by the bunched gene, serves to integrate opposing bone morphogenic protein (BMP) and epidermal growth factor (EGF) signals during oogenesis. Similarly, mammalian TSC-22 expression is regulated by several families of secreted signaling molecules in cultured cells. Here, we show that chick TSC-22 is dynamically expressed in the condensing feather bud, as well as in many tissues of the chick embryo. BMP-2/4, previously shown to inhibit bud development, repress TSC-22 expression during feather bud formation in vivo. Noggin, a BMP antagonist, promotes TSC-22 expression. EGF, TGF-,, and fibroblast growth factor all promote both feather bud development and TSC-22 expression; each can promote ectopic feather buds that are regularly spaced between existing feather buds. Thus, TSC-22 is a candidate to integrate small imbalances in receptor tyrosine kinase and BMP signaling during feather tract development to generate stable and reproducible morphogenetic responses. © 2001 Wiley-Liss, Inc. [source]

    Aberrant promoter methylation of the TPEF gene in esophageal squamous cell carcinoma

    DISEASES OF THE ESOPHAGUS, Issue 7 2008
    B.-J. Zhao
    SUMMARY., Aberrant methylation of tumor suppressor genes plays an important role in the development of esophageal squamous cell carcinoma (ESCC). The purpose of the present study was to identify the epigenetic changes in ESCC. Methylation-sensitive arbitrarily primed polymerase chain reaction (MS AP-PCR) analysis was used on 22 matched ESCC tumors and adjacent normal tissues. Through this screen we identified a frequently methylated fragment that showed a high homology to the 5,-CpG island of the gene encoding a transmembrane protein containing epidermal growth factor and follistatin domains (TPEF). The methylation status of the TPEF gene was then detected by bisulfite sequencing and the levels of TPEF mRNA were detected by RT-PCR. In addition, the effects of a methylation inhibitor 5-aza-2,-deoxycytidine on TPEF mRNA expression was determined in cells of ESCC cell lines. Hypermethylation of the 5,-CpG island of TPEF was found in 12 of 22 (54.5%) primary tumors. Reverse transcription PCR analysis demonstrated that TPEF mRNA expression was significantly lower in tumors than in adjacent normal tissues, which is associated with promoter hypermethylation. In addition, treatment of ESCC cell lines with 5-aza-2,-deoxycytidine led to re-expression of the TPEF transcript. In conclusion, we observed promoter of TPEF gene is frequently hpermethylated, and is associated with the loss of TPEF mRNA expression in ESCC samples. Promoter hypermethylation of TPEF gene may play a role in the development of ESCC. [source]

    A microfluidic device for characterizing the invasion of cancer cells in 3-D matrix

    ELECTROPHORESIS, Issue 24 2009
    Tingjiao Liu
    Abstract A microfluidic device was developed for the study of directed invasion of cancer cells in 3-D matrix with concentration gradient. This device consists of two parallel perfusion channels connected by two cell culture chambers. To mimic extracellular matrix (ECM), gelled basement membrane extract (BME) was used to support 3-D distribution of breast cancer cells (MCF7) in cell culture chambers. A stable linear concentration gradient of epidermal growth factor (EGF) was generated across the chambers by continuous perfusion. Using the device, we investigated MCF7 cell invasion induced by different concentrations of EGF in 3-D matrix. It was found that cancer cells responded to EGF stimulation with forming cellular protrusions and migrating towards high EGF concentration. We further investigated the anti-invasion effect of GM 6001, a matrix metalloproteinase inhibitor. We identified that matrix metalloproteinase inhibition repressed both cellular protrusion formation and cell migration in 3-D matrix. These findings suggest that EGF is able to induce MCF7 cell invasion in 3-D extracellular matrix and this effect is dependent on proteolytic activity. This device is relatively simple to construct and operate. It should be a useful platform for elucidating the mechanism of cancer invasion and screening anti-invasion drugs for cancer therapy. [source]

    Candidate genes for cannabis use disorders: findings, challenges and directions

    ADDICTION, Issue 4 2009
    Arpana Agrawal
    ABSTRACT Aim Twin studies have shown that cannabis use disorders (abuse/dependence) are highly heritable. This review aims to: (i) review existing linkage studies of cannabis use disorders and (ii) review gene association studies, to identify potential candidate genes, including those that have been tested for composite substance use disorders and (iii) to highlight challenges in the genomic study of cannabis use disorders. Methods Peer-reviewed linkage and candidate gene association studies are reviewed. Results Four linkage studies are reviewed: results from these have homed in on regions on chromosomes 1, 3, 4, 9, 14, 17 and 18, which harbor candidates of predicted biological relevance, such as monoglyceride lipase (MGLL) on chromosome 3, but also novel genes, including ELTD1[epidermal growth factor (EGF), latrophilin and seven transmembrane domain containing 1] on chromosome 1. Gene association studies are presented for (a) genes posited to have specific influences on cannabis use disorders: CNR1, CB2, FAAH, MGLL, TRPV1 and GPR55 and (b) genes from various neurotransmitter systems that are likely to exert a non-specific influence on risk of cannabis use disorders, e.g. GABRA2, DRD2 and OPRM1. Conclusions There are challenges associated with (i) understanding biological complexity underlying cannabis use disorders (including the need to study gene,gene and gene,environment interactions), (ii) using diagnostic versus quantitative phenotypes, (iii) delineating which stage of cannabis involvement (e.g. use versus misuse) genes influence and (iv) problems of sample ascertainment. [source]

    Expression of milk fat globule epidermal growth factor,8 in immature dendritic cells for engulfment of apoptotic cells

    EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 5 2004
    Kay Miyasaka
    Abstract Milk fat globule epidermal growth factor,8 (MFG-E8) is a protein that stimulates the engulfment of apoptotic cells by phagocytes. Here, we show that mouse immature dendritic cells (DC) generated in vitro by culturing bone marrow progenitors in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF), and Langerhans cells present in the skins, expressed MFG-E8. Bone marrow-derived macrophages generated by M-CSF did not express MFG-E8. MFG-E8 expressed in immature DC was found to be secreted as exosomes. The expression of MFG-E8 was significantly suppressed when the immature DC were induced to mature by treating them with lipopolysaccharides. This expression of MFG-E8 was well correlated with the ability of the cells to engulf apoptotic cells. That is,immature DC phagocytosed apoptotic cells more efficiently than did mature DC or bone marrow-derived macrophages. The ability of immature DC to engulf apoptotic cells was severely reduced when the immature DC were prepared from MFG-E8-deficient mice. These results indicated that MFG-E8 plays an essential role in the engulfment of apoptotic cells by bone marrow-derived immature DC. [source]

    Neurosphere generation from dental pulp of adult rat incisor

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2008
    Ryo Sasaki
    Abstract Dental pulp is a potential source of cells that can be used in cell replacement therapy for various nervous system disorders. Here we report that adult rat dental pulp cells have the ability to form neurospheres when cultured in serum-free culture medium on super-hydrophilic plates. The cells within small spheres continued to grow, and the dental pulp-derived cells generated large spheres. Sphere formation was dependent on exogenously supplied basic-fibroblast growth factor, but not on epidermal growth factor, and the formation and growth of dental pulp-derived spheres were negatively regulated by transforming growth factor-,. Plating cells that were dissociated from spheres on an adhesive substrate resulted in differentiation into Tuj1- and MAP2-positive neuronal cells. Analysis of the three-dimensional structure of dental pulp-derived spheres shows that they contained nestin-positive progenitors, Tuj1-positive neuronal cells and S100-positive glial cells. We found that spheres contained CD81 (TAPA1) and nestin double-positive cells, and identified a small population of CD81 and nestin double-positive cells in the odontoblast layer of the dental pulp. Flow cytometric analysis showed that CD81-positive cells were enriched in the spheres compared with the dental pulp tissue. Bromodeoxyuridine (BrdU) staining showed that nestin- and BrdU-positive cells were located only in the apical portion of the dental pulp, and the apical portion produced a large number of large-sized spheres. These data suggest that the CD81 and nestin double-positive cells localized in the odontoblast layer of the apical portion of the dental pulp may have the ability to grow and form neurospheres. [source]