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Sample records for activated growth factor

  1. Transcription-dependent epidermal growth factor receptor activation by hepatocyte growth factor.

    PubMed

    Reznik, Thomas E; Sang, Yingying; Ma, Yongxian; Abounader, Roger; Rosen, Eliot M; Xia, Shuli; Laterra, John

    2008-01-01

    The mechanisms and biological implications of coordinated receptor tyrosine kinase coactivation remain poorly appreciated. Epidermal growth factor receptor (EGFR) and c-Met are frequently coexpressed in cancers, including those associated with hepatocyte growth factor (HGF) overexpression, such as malignant astrocytoma. In a previous analysis of the HGF-induced transcriptome, we found that two EGFR agonists, transforming growth factor-alpha and heparin-binding epidermal growth factor-like growth factor (HB-EGF), are prominently up-regulated by HGF in human glioma cells. We now report that stimulating human glioblastoma cells with recombinant HGF induces biologically relevant EGFR activation. EGFR phosphorylation at Tyr(845) and Tyr(1068) increased 6 to 24 h after cell stimulation with HGF and temporally coincided with the induction of transforming growth factor-alpha (~5-fold) and HB-EGF (~23-fold) expression. Tyr(845) and Tyr(1068) phosphorylation, in response to HGF, was inhibited by cycloheximide and actinomycin D, consistent with a requirement for DNA transcription and RNA translation. Specifically, blocking HB-EGF binding to EGFR with the antagonist CRM197 inhibited HGF-induced EGFR phosphorylation by 60% to 80% and inhibited HGF-induced S-G(2)-M transition. CRM197 also inhibited HGF-induced anchorage-dependent cell proliferation but had no effect on HGF-mediated cytoprotection. These findings establish that EGFR can be activated with functional consequences by HGF as a result of EGFR ligand expression. This transcription-dependent cross-talk between the HGF receptor c-Met and EGFR expands our understanding of receptor tyrosine kinase signaling networks and may have considerable consequences for oncogenic mechanisms and cancer therapeutics.

  2. The suppression of fibroblast growth factor 2/fibroblast growth factor 4-dependent tumour angiogenesis and growth by the anti-growth factor activity of dextran derivative (CMDB7).

    PubMed Central

    Bagheri-Yarmand, R.; Kourbali, Y.; Mabilat, C.; Morère, J. F.; Martin, A.; Lu, H.; Soria, C.; Jozefonvicz, J.; Crépin, M.

    1998-01-01

    Our previous studies showed that carboxymethyl benzylamide dextran (CMDB7) blocks basic fibroblast growth factor (FGF-2)-dependent cell proliferation of a human breast epithelial line (HBL100), suggesting its potential role as a potent antiangiogenic substance. The derived cell line (HH9), which was transformed with the hst/FGF4 gene, has been shown to be highly proliferative in vitro and to induce angiogenic tumours in nude mice. We show here that CMDB7 inhibits the mitogenic activities of the conditioned media from HBL 100 and HH9 cells in a dose-dependent manner. When HH9 cells were injected s.c. into nude mice, CMDB7 treatment (300 mg kg(-1) week(-1)) suppressed the tumour take and the tumour growth by about 50% and 80% respectively. Immunohistochemical analysis showed a highly significant decrease, by more than threefold, in the endothelial density of viable tumour regions, together with a significant increase in the necrosis area. This antiangiogenic activity of CMDB7 was further demonstrated by direct inhibition of calf pulmonary artery (CPAE) and human umbilical vein (HUVEC) endothelial cell proliferation and migration in vitro. In addition, we showed that CMDB7 inhibits specifically the mitogenic effects of the growth factors that bind to heparin such as FGF-2, FGF-4, platelet-derived growth factor (PDGF-BB) and transforming growth factor (TGF-beta1), but not those of epidermal growth factor (EGF) and insulin-like growth factor (IGF-1). These results demonstrate that CMDB7 inhibits FGF-2/FGF-4-dependent tumour growth and angiogenesis, most likely by disrupting the autocrine and paracrine effects of growth factors released from the tumour cells. Images Figure 4 PMID:9662260

  3. Total Chemical Synthesis of Biologically Active Vascular Endothelial Growth Factor

    SciTech Connect

    Mandal, Kalyaneswar; Kent, Stephen B.H.

    2011-09-15

    The 204-residue covalent-dimer vascular endothelial growth factor (VEGF, see picture) with full mitogenic activity was prepared from three unprotected peptide segments by one-pot native chemical ligations. The covalent structure of the synthetic VEGF was confirmed by precise mass measurement, and the three-dimensional structure of the synthetic protein was determined by high-resolution X-ray crystallography.

  4. Overexpression and activation of epidermal growth factor receptor in hemangioblastomas

    PubMed Central

    Chen, Gregory J.; Karajannis, Matthias A.; Newcomb, Elizabeth W.

    2010-01-01

    Hemangioblastomas frequently develop in patients with von Hippel-Lindau (VHL) disease, an autosomal dominant genetic disorder. The tumors are characterized by a dense network of blood capillaries, often in association with cysts. Although activation of receptor tyrosine kinase (RTK) signaling, including epidermal growth factor receptor (EGFR) has been implicated in the development of malignant brain tumors such as high-grade gliomas, little is known about the role of RTK signaling in hemangioblastomas. To address this issue, we examined hemangioblastoma tumor specimens using receptor tyrosine kinase (RTK) activation profiling and immunohistochemistry. Six human hemangioblastomas were analyzed with a phospho-RTK antibody array, revealing EGFR phosphorylation in all tumors. EGFR expression was confirmed by immunohistochemistry in all tumors analyzed and downstream effector pathway activation was demonstrated by positive staining for phospho-AKT. Our findings suggest that, in primary hemangioblastomas, RTK upregulation and signaling predominantly involves EGFR, providing an attractive molecular target for therapeutic intervention. PMID:20730556

  5. Hepatocyte growth factor, hepatocyte growth factor activator and arginine in a rat fulminant colitis model

    PubMed Central

    Zwintscher, Nathan P.; Shah, Puja M.; Salgar, Shashikumar K.; Newton, Christopher R.; Maykel, Justin A.; Samy, Ahmed; Jabir, Murad; Steele, Scott R.

    2016-01-01

    Introduction Dextran sodium sulfate (DSS) is commonly used to induce a murine fulminant colitis model. Hepatocyte growth factor (HGF) has been shown to decrease the symptoms of inflammatory bowel disease (IBD) but the effect of its activator, HGFA, is not well characterized. Arginine reduces effects of oxidative stress but its effect on IBD is not well known. The primary aim is to determine whether HGF and HGFA, or arginine will decrease IBD symptoms such as pain and diarrhea in a DSS-induced fulminant colitis murine model. Methods A severe colitis was induced in young, male Fischer 344 rats with 4% (w/v) DSS oral solution for seven days; rats were sacrificed on day 10. Rats were divided into five groups of 8 animals: control, HGF (700 mcg/kg/dose), HGF and HGFA (10 mcg/dose), HGF and arginine, and high dose HGF (2800 mcg/kg/dose). Main clinical outcomes were pain, diarrhea and weight loss. Blinded pathologists scored the terminal ileum and distal colon. Results DSS reliably induced severe active colitis in 90% of animals (n = 36/40). There were no differences in injury scores between control and treatment animals. HGF led to 1.38 fewer days in pain (p = 0.036), while arginine led to 1.88 fewer days of diarrhea (P = 0.017) compared to controls. 88% of HGFA-treated rats started regaining weight (P < 0.001). Discussion/Conclusion Although treatment was unable to reverse fulminant disease, HGF and arginine were associated with decreased days of pain and diarrhea. These clinical interventions may reduce associated symptoms for severe IBD patients, even when urgent surgical intervention remains the only viable option. PMID:27144006

  6. Water Activity Limits the Hygroscopic Growth Factor of Organic Aerosols

    NASA Astrophysics Data System (ADS)

    Rodriguez, L. I.; Cabrera, J. A.; Golden, D.; Tabazadeh, A.

    2007-12-01

    In this work we study the hygroscopic behavior of organic aerosols, which has important implications for Earth's climate. The hygroscopic growth factor (HGF) is defined as the ratio of the diameter of a spherical particle when it is exposed to dry conditions to that at humid conditions. We present a new formulation to express the HGF of an aerosol particle as a function of water activity (aw) in the aqueous phase. This new formulation matches reported HGFs for common inorganic salts and water-miscible organic particles that are known to deliquesce into aqueous drops at high relative humidities (RH). Many studies use tandem differential mobility analyzers (TDMA) to determine the HGF of organic aerosols. For example, Brooks et al. used a TDMA to measure a HGF of 1.2 for 2 μm phthalic acid (PA) particles at 90% RH (aw= 0.9). However, water activity limits the growth of a particle that can be attributed to water uptake. We have assembled a vapor pressure apparatus to measure aw of aqueous solutions at room temperature. Measured water activities for PA, used in our growth formulation, yield a HGF of ~ 1.0005 for 2 μm PA particles at 90% RH. Comparing our results against Brooks et al. suggests that TDMA experiments may grossly overestimate the HGF of PA particles since water activity limits this growth to below 1.0005. Alternatively, we suggest that the adsorption of a negligible mass of water by a highly porous PA particle can lead to an apparent growth in particle size by changing its morphology. Other studies also use TDMAs to measure HGFs of secondary organic aerosols (SOAs). HGFs reported for SOAs are very similar to PA, suggesting that the observed growth may be due to morphological changes in particle size rather than water uptake as commonly assumed. We built a smog chamber where an organic precursor, such as d-limonene, reacts with nitrogen oxides under UV radiation to produce SOAs. We compare the HGFs for SOAs obtained with our method to those obtained with

  7. [Antifibrillatory activity of dipeptide antagonist of nerve growth factor].

    PubMed

    Kryzhanovskiĭ, S A; Stoliarchuk, V N; Vititnova, M B; Tsorin, I B; Pekel'dina, E S; Gudasheva, T A

    2012-01-01

    In experiments on anesthetized rats were assessed antifibrillatoty action of dipeptide GK-1. This compound is the fragment of fourth loop of nerve growth factor (NGF) and manifests antagonistic activity in respect to TrkA receptor, that specified for NGF. It is shown that this compound is able to significantly increase the threshold of electrical fibrillation of the heart and its effectiveness is not inferior to the reference antiarrhythmics I and III class on Vaughan Williams classification. However, unlike the latter, antifibrillatory action of dipeptide GK-1 was delayed and realized within 40-60 minutes after its administration. It is discussed possible mechanisms underlying antifibrillatory action of dipeptide GK-1, that, to some extent, may be associated with its ability to change the reactivity of beta-adrenergic structures of the heart.

  8. Growth factors

    SciTech Connect

    Golde, D.W.; Herschman, H.R.; Lusis, A.J.; Groopman, J.E.

    1980-05-01

    Humoral regulation of somatic and hematopoietic cell growth has been intensely investigated during the past decade. Growth hormone is unique because it regulates the size of the person within the constraints of the genetic program. The somatomedins and insulin growth factors are low molecular weight polypeptides believed to mediate some functions of growth hormone. Epithelial growth factor and nerve growth factor are well-characterized polypeptides that influence the growth and differentiation of epithelial and neural tissues and interact with specific cell surface receptors. The hematopoietins are a family of polypeptide hormones that specifically regulate the proliferation and differentiation of stem cells giving rise to erythrocytes, granulocytes, monocytes, megakaryocytes, and B and T lymphocytes. Platelet-derived growth factor modulates the proliferation of fibroblasts in vitro and may have a role in the development of atherosclerosis and myelofibrosis. New knowledge on the biochemistry and physiology of growth factors will probably have a substantial impact on our understanding of human diseases involving abnormal cell growth.

  9. Transforming growth factor-beta requires its target plasminogen activator inhibitor-1 for cytostatic activity.

    PubMed

    Kortlever, Roderik M; Nijwening, Jeroen H; Bernards, René

    2008-09-01

    The cytokine transforming growth factor beta (TGFbeta) has strong antiproliferative activity in most normal cells but contributes to tumor progression in the later stages of oncogenesis. It is not fully understood which TGFbeta target genes are causally involved in mediating its cytostatic activity. We report here that suppression of the TGFbeta target gene encoding plasminogen activator inhibitor-1 (PAI-1) by RNA interference leads to escape from the cytostatic activity of TGFbeta both in human keratinocytes (HaCaTs) and primary mouse embryo fibroblasts. Consistent with this, PAI-1 knock-out mouse embryo fibroblasts are also resistant to TGFbeta growth arrest. Conversely, we show that ectopic expression of PAI-1 in proliferating HaCaT cells induces a growth arrest. PAI-1 knockdown does not interfere with canonical TGFbeta signaling as judged by SMAD phosphorylation and induction of bona fide TGFbeta target genes. Instead, knockdown of PAI-1 results in sustained activation of protein kinase B. Significantly, we find that constitutive protein kinase B activity leads to evasion of the growth-inhibitory action of TGFbeta. Our data are consistent with a model in which induction of PAI-1 by TGFbeta is critical for the induction of proliferation arrest.

  10. Peptide growth factors, part B

    SciTech Connect

    Barnes, D.; Sirbasku, D.A.

    1987-01-01

    This book discusses the following topics: Platelet-Derived Growth Factor;Nerve and Glial Growth Factors;PC12 Pheochromocytoma Cells;Techniques for the Study of Growth Factor Activity;Genetic Approaches and Biological Effects.

  11. Peptide growth factors, part A

    SciTech Connect

    Barnes, D.; Sirbasku, D.A.

    1987-01-01

    This book contains information on the following topics: Epidermal Growth Factor;Transforming Growth Factors;Bone and Cartilage Growth Factors;Somatomedin/Insulin-Like Growth Factors;Techniques for the Study of Growth Factor Activity;Assays, Phosphorylation, and Surface Membrane Effects.

  12. Regulated shedding of syndecan-1 and -4 ectodomains by thrombin and growth factor receptor activation.

    PubMed

    Subramanian, S V; Fitzgerald, M L; Bernfield, M

    1997-06-01

    The syndecan family of transmembrane heparan sulfate proteoglycans is abundant on the surface of all adherent mammalian cells. Syndecans bind and modify the action of various growth factors/cytokines, proteases/antiproteases, cell adhesion molecules, and extracellular matrix components. Syndecan expression is highly regulated during wound repair, a process orchestrated by many of these effectors. Each syndecan ectodomain is shed constitutively by cultured cells, but the mechanism and significance of this shedding are not understood. Therefore, we examined (i) whether physiological agents active during wound repair influence syndecan shedding, and (ii) whether wound fluids contain shed syndecan ectodomains. Using SVEC4-10 endothelial cells we find that certain proteases and growth factors accelerate shedding of the syndecan-1 and -4 ectodomains. Protease-accelerated shedding is completely inhibited by serum-containing media. Thrombin activity is duplicated by the 14-amino acid thrombin receptor agonist peptide that directly activates the thrombin receptor and is not inhibited by serum. Epidermal growth factor family members accelerate shedding but FGF-2, platelet-derived growth factor-AB, transforming growth factor-beta, tumor necrosis factor-alpha, and vascular endothelial cell growth factor 165 do not. Shed ectodomains are soluble, stable in the conditioned medium, have the same size core proteins regardless whether shed at a basal rate, or accelerated by thrombin or epidermal growth factor-family members and are found in acute human dermal wound fluids. Thus, shedding is accelerated by activation of at least two distinct receptor classes, G protein-coupled (thrombin) and protein tyrosine kinase (epidermal growth factor). Proteases and growth factors active during wound repair can accelerate syndecan shedding from cell surfaces. Regulated shedding of syndecans suggests physiological roles for the soluble proteoglycan ectodomains.

  13. Stimulation of protein phosphatase activity by insulin and growth factors in 3T3 cells

    SciTech Connect

    Chan, C.P.; McNall, S.J.; Krebs, E.G.; Fischer, E.H. )

    1988-09-01

    Incubation of Swiss mouse 3T3-D1 cells with physiological concentrations of insulin resulted in a rapid and transient activation of protein phosphatase activity as measure by using ({sup 32}P)phosphorylase {alpha} as substrate. Activation reached a maximum level (140% of control value) within 5 min of addition and returned to control levels within 20 min. The effect of insulin was dose-dependent with half-maximal activation occurring at {approx}5 nM insulin. This activity could be completely inhibited by addition of the heat-stable protein inhibitor 2, which suggests the presence of an activated type-1 phosphatase. Similar effects on phosphatase activity were seen when epidermal growth factor and platelet-derived growth factor were tested. These results suggest that some of the intracellular effects caused by insulin and growth factors are mediated through the activation of a protein phosphatase.

  14. Activation of p38 Mitogen-Activated Protein Kinase Promotes Epidermal Growth Factor Receptor Internalization

    PubMed Central

    Vergarajauregui, Silvia; Miguel, Anitza San; Puertollano, Rosa

    2006-01-01

    Endocytic trafficking plays an important role in the regulation of the epidermal growth factor receptor (EGFR). To address if cellular kinases regulate EGFR internalization, we used anisomycin, a potent activator of kinase cascades in mammalian cells, especially the stress-activated mitogen-activated protein (MAP) kinase subtypes. Here, we report that activation of p38 MAP kinase by anisomycin is sufficient to induce internalization of EGFR. Anisomycin and EGF employ different mechanisms to promote EGFR endocytosis as anisomycin-induced internalization does not require tyrosine kinase activity or ubiquitination of the receptor. In addition, anisomycin treatment did not result in delivery and degradation of EGFR at lysosomes. Incubation with a specific inhibitor of p38, or depletion of endogenous p38 by small interfering RNAs, abolished anisomycin-induced internalization of EGFR while having no effect on transferrin endocytosis, indicating that the effect of p38 activation on EGFR endocytosis is specific. Interestingly, inhibition of p38 activation also abolished endocytosis of EGFR induced by UV radiation. Our results reveal a novel role for p38 in the regulation of EGFR endocytosis and suggest that stimulation of EGFR internalization by p38 might represent a general mechanism to prevent generation of proliferative or anti-apoptotic signals under stress conditions. PMID:16683917

  15. Models for the activation pathway of epidermal growth factor receptor protein-tyrosine kinase

    SciTech Connect

    Campion, S.R.; Niyogi, S.K. )

    1991-03-15

    Activation of the epidermal growth factor (EGF) receptor's intrinsic protein-tyrosine kinase activity, which occurs upon formation of the receptor-ligand complex, is the critical regulatory event affecting the subsequent EGF-dependent cellular responses leading to DNA synthesis and cell proliferation. The molecular mechanism by which EGF-dependent activation of receptor kinase activity takes place is not clearly understood. In this study, the growth factor-dependent activation of the EGF receptor tyrosine kinase was examined in vitro using detergent-solubilized, partially purified GEF receptors from A5431 human epidermoid carcinoma cells. Evaluation of the cooperativity observed in the EGF-dependent activation of soluble receptor tyrosine kinase would suggest a mechanism requiring the binding of the EGF peptide to both ligand binding sites on a receptor dimer to induce full receptor kinase activity. Equations describing potential cooperative kinase activation pathways have been examined. The theoretical system which best simulates the allosteric regulation observed in the experimental kinase activation data is that describing multiple essential activation. In addition, studies using mutant analogs of the EGF peptide ligand appear to confirm the requirement for an essential conformational change in the receptor-ligand complex to activate the receptor kinase activity. Several mutant growth factor analogues are able to occupy the ligand binding sites on the receptor without inducing the fully active receptor conformation.

  16. Growth factor signalling.

    PubMed

    de Laat, S W; Boonstra, J; Defize, L H; Kruijer, W; van der Saag, P T; Tertoolen, L G; van Zoelen, E J; den Hertog, J

    1999-01-01

    Signalling between cells in the developing vertebrate embryo is essential for normal embryonic development. In the mid 1970's, signal transduction research started at the Hubrecht Laboratory with special emphasis on analysis of the signalling mechanisms that direct cell proliferation and differentiation. The introduction of in vitro model systems contributed tremendously to the success of the signal transduction research at the Hubrecht Laboratory. Initially neuroblastoma cell lines, and later embryonal carcinoma and embryonal stem cells played an important role in identification of the molecular key players in developmental signalling. For instance, embryonal carcinoma cells were used to identify and characterise polypeptide growth factors. Growth factor signalling research was extended to analysis of growth factor receptor activation. Moreover, the second messenger systems that are linked to growth factor receptors were studied, as well as the nuclear responses to growth factor receptor activation. Finally, the role of growth factor signalling in differentiation was established using embryonal carcinoma cells. Here, we will review work that was characteristic for the growth factor receptor signalling research that was done at the Hubrecht Laboratory between 1980 and the early 1990's.

  17. Cloning and biological activity of epigen, a novel member of the epidermal growth factor superfamily.

    PubMed

    Strachan, L; Murison, J G; Prestidge, R L; Sleeman, M A; Watson, J D; Kumble, K D

    2001-05-25

    High throughput sequencing of a mouse keratinocyte library was used to identify an expressed sequence tag with homology to the epidermal growth factor (EGF) family of growth factors. We have named the protein encoded by this expressed sequence tag Epigen, for epithelial mitogen. Epigen encodes a protein of 152 amino acids that contains features characteristic of the EGF superfamily. Two hydrophobic regions, corresponding to a putative signal sequence and transmembrane domain, flank a core of amino acids encompassing six cysteine residues and two putative N-linked glycosylation sites. Epigen shows 24-37% identity to members of the EGF superfamily including EGF, transforming growth factor alpha, and Epiregulin. Northern blotting of several adult mouse tissues indicated that Epigen was present in testis, heart, and liver. Recombinant Epigen was synthesized in Escherichia coli and refolded, and its biological activity was compared with that of EGF and transforming growth factor alpha in several assays. In epithelial cells, Epigen stimulated the phosphorylation of c-erbB-1 and mitogen-activated protein kinases and also activated a reporter gene containing enhancer sequences present in the c-fos promoter. Epigen also stimulated the proliferation of HaCaT cells, and this proliferation was blocked by an antibody to the extracellular domain of the receptor tyrosine kinase c-erbB-1. Thus, Epigen is the newest member of the EGF superfamily and, with its ability to promote the growth of epithelial cells, may constitute a novel molecular target for wound-healing therapy. PMID:11278323

  18. Glypican-1 nanoliposomes for potentiating growth factor activity in therapeutic angiogenesis.

    PubMed

    Monteforte, Anthony J; Lam, Brian; Das, Subhamoy; Mukhopadhyay, Somshuvra; Wright, Catherine S; Martin, Patricia E; Dunn, Andrew K; Baker, Aaron B

    2016-07-01

    Therapeutic angiogenesis is a highly appealing concept for treating tissues that become ischemic due to vascular disease. A major barrier to the clinical translation of angiogenic therapies is that the patients that are in the greatest need of these treatments often have long term disease states and co-morbidities, such as diabetes and obesity, that make them resistant to angiogenic stimuli. In this study, we identified that human patients with type 2 diabetes have reduced levels of glypican-1 in the blood vessels of their skin. The lack of this key co-receptor in the tissue may make the application of exogenous angiogenic growth factors or cell therapies ineffective. We created a novel therapeutic enhancer for growth factor activity consisting of glypican-1 delivered in a nanoliposomal carrier (a "glypisome"). Here, we demonstrate that glypisomes enhance FGF-2 mediated endothelial cell proliferation, migration and tube formation. In addition, glypisomes enhance FGF-2 trafficking by increasing both uptake and endosomal processing. We encapsulated FGF-2 or FGF-2 with glypisomes in alginate beads and used these to deliver localized growth factor therapy in a murine hind limb ischemia model. Co-delivery of glypisomes with FGF-2 markedly increased the recovery of perfusion and vessel formation in ischemic hind limbs of wild type and diabetic mice in comparison to mice treated with FGF-2 alone. Together, our findings support that glypisomes are effective means for enhancing growth factor activity and may improve the response to local angiogenic growth factor therapies for ischemia. PMID:27101205

  19. Synergistic activation of cells by Epstein-Barr virus and B-cell growth factor.

    PubMed Central

    Hutt-Fletcher, L M

    1987-01-01

    Infection with Epstein-Barr virus (EBV) is initiated by virus binding to the C3dg-C3d receptor CR2. Several workers have implicated this receptor in the control of B-cell activation by examining the effects of antibodies to CR2 and isolated C3d on B-cell proliferation and differentiation. We report here on the activating effects of irradiated EBV, which retains its capacity to bind to CR2 but loses its ability to function as a T-independent B-cell activator. EBV synergized with B-cell growth factor in the induction of uptake of tritiated thymidine by T cell-depleted leukocytes from seronegative donors but did not induce secretion of immunoglobulin. Synergism could be inhibited with an anti-viral antibody that inhibited binding of EBV to CR2. No similar synergism was found between EBV and recombinant interleukin 2, interleukin 1 alpha, or gamma interferon or with the lipid A fraction of bacterial lipopolysaccharide. EBV may thus initiate B-cell activation as it binds to CR2. Infectious virus may, under normal circumstances, induce the cell to make those growth factors necessary to support B-cell proliferation; the difficulty of transforming cells with transfected EBV DNA may in part reflect the absence of an activation event provided by intact virus as it attaches to CR2. The synergism of EBV and B-cell growth factor more clearly distinguishes the effects of B-cell growth factor from those of interleukin 1 and interleukin 2 in other models of B-cell activation. Thus, this may be a useful model for further delineation of unique effects of B-cell growth factor on B-cell function. PMID:3027404

  20. Nerve growth factor-like activity detected in equine peripheral blood after running exercise.

    PubMed

    Matsuda, H; Koyama, H; Oikawa, M; Yoshihara, T; Kaneko, M

    1991-08-01

    Addition of sera, collected from Thoroughbred horses after sprint exercise, induced significant neurite outgrowth from chick embryo dorsal root ganglia after a 24-hour culture. The nerve growth factor (NGF)-like activity was detected in sera collected immediately, or 1 hour or more, after the exercise. These findings suggest a possible role of serum NGF-like activity under stress conditions (running exercise) of horses.

  1. New microbial growth factor

    NASA Technical Reports Server (NTRS)

    Bok, S. H.; Casida, L. E., Jr.

    1977-01-01

    A screening procedure was used to isolate from soil a Penicillium sp., two bacterial isolates, and a Streptomyces sp. that produced a previously unknown microbial growth factor. This factor was an absolute growth requirement for three soil bacteria. The Penicillium sp. and one of the bacteria requiring the factor, an Arthrobacter sp., were selected for more extensive study concerning the production and characteristics of the growth factor. It did not seem to be related to the siderochromes. It was not present in soil extract, rumen fluid, or any other medium component tested. It appears to be a glycoprotein of high molecular weight and has high specific activity. When added to the diets for a meadow-vole mammalian test system, it caused an increased consumption of diet without a concurrent increase in rate of weight gain.

  2. Biological activity of recombinant human growth factors released from biocompatible bone implants.

    PubMed

    Ziegler, Joerg; Anger, Dominique; Krummenauer, Frank; Breitig, Dieter; Fickert, Stefan; Guenther, Klaus-Peter

    2008-07-01

    The present investigation was performed to study the bioactivity of osteoinductive and osteoproliferative growth factors after release from biocompatible bone implants. Three types of porous carriers were used in this study: hydroxyapatite, alpha tricalcium phosphate, and a neutralized glass ceramic. Implants were loaded with recombinant human bone morphogenetic protein 2 (rh-BMP-2) and recombinant human basic fibroblast growth factor (rh-bFGF) in a concentration of 2 microg/150 microL PBS each. The released growth factors were then applicated into SAOS-2-cell cultures. After 3, 5, and 7 days cell differentiation was measured by the activity of alkaline phosphatase (ALP), cell proliferation by using a MTT assay as well as a cell counter. Rh-BMP-2 released during the first hour from the scaffolds led to a significant increase of the activity of ALP in the incubated SAOS-2-cell culture after 3, 5, and 7 days. However, the incubation with rh-BMP-2 released after 24 h was not found to increase the expression of ALP. The incubation of cell cultures with rh-bFGF released during the first hour led to a significant increase of cell number and of extinction in the MTT assay, whereas this increase was not observed after incubation with rh-bFGF released after 24 h. The in vitro measured biological activity of released growth factors from the surface of synthetic implants is time-depending. If prolonged osteoinductive and osteoproliferative potency of growth factors is desired, a modified application technique should be chosen to stabilize those proteins.

  3. ADP-ribosylation factor 1 controls the activation of the phosphatidylinositol 3-kinase pathway to regulate epidermal growth factor-dependent growth and migration of breast cancer cells.

    PubMed

    Boulay, Pierre-Luc; Cotton, Mathieu; Melançon, Paul; Claing, Audrey

    2008-12-26

    Activation of intracellular signaling pathways by growth factors is one of the major causes of cancer development and progression. Recent studies have demonstrated that monomeric G proteins of the Ras family are key regulators of cell proliferation, migration, and invasion. Using an invasive breast cancer cell lines, we demonstrate that the ADP-ribosylation factor 1 (ARF1), a small GTPase classically associated with the Golgi, is an important regulator of the biological effects induced by epidermal growth factor. Here, we show that this ARF isoform is activated following epidermal growth factor stimulation and that, in MDA-MB-231 cells, ARF1 is found in dynamic plasma membrane ruffles. Inhibition of endogenous ARF1 expression results in the inhibition of breast cancer cell migration and proliferation. The underlying mechanism involves the activation of the phosphatidylinositol 3-kinase pathway. Our data demonstrate that depletion of ARF1 markedly impairs the recruitment of the phosphatidylinositol 3-kinase catalytic subunit (p110alpha) to the plasma membrane, and the association of the regulatory subunit (p85alpha) to the activated receptor. These results uncover a novel molecular mechanism by which ARF1 regulates breast cancer cell growth and invasion during cancer progression.

  4. Fibroblast growth factor, but not activin, is a potent activator of mitogen-activated protein kinase in Xenopus explants.

    PubMed Central

    Graves, L M; Northrop, J L; Potts, B C; Krebs, E G; Kimelman, D

    1994-01-01

    Isolated explants from the animal hemisphere of Xenopus embryos were incubated with Xenopus basic fibroblast growth factor (XbFGF) or human activin A. XbFGF incubation resulted in the rapid activation of mitogen-activated protein kinase (MAPK) and ribosomal S6 protein kinase (pp90rsk) in a dose-dependent manner with the highest levels of activation occurring at 50 ng/ml. Maximal activation occurred within 6-10 min after the addition of growth factor, and the activity of both kinases declined to unstimulated levels after 30 min. Activin was unable to activate either MAPK or pp90rsk in the Xenopus explants to a substantial level, although it induced dorsal mesoderm better than XbFGF under the same experimental conditions. The regulatory protein Xwnt-8 did not activate MAPK, nor did it enhance the activation of MAPK by XbFGF. XbFGF was able to activate MAPK through at least the midgastrula stage, suggesting that this family of growth factors may have a role in gastrula-stage events. Images PMID:7510404

  5. A role for the perlecan protein core in the activation of the keratinocyte growth factor receptor.

    PubMed Central

    Ghiselli, G; Eichstetter, I; Iozzo, R V

    2001-01-01

    Perlecan, a widespread heparan sulphate (HS) proteoglycan, is directly involved in the storing of angiogenic growth factors, mostly members of the fibroblast growth factor (FGF) gene family. We have previously shown that antisense targeting of the perlecan gene causes a reduced growth and responsiveness to FGF7 [also known as keratinocyte growth factor (KGF)] in human cancer cells, and that the perlecan protein core interacts specifically with FGF7. In the present paper, we have investigated human colon carcinoma cells in which the perlecan gene was disrupted by targeted homologous recombination. After screening over 1000 clones, we obtained two clones heterozygous for the null mutation with no detectable perlecan, indicating that the other allele was non-functioning. The perlecan-deficient cells grew more slowly, did not respond to FGF7 with or without the addition of heparin, and were less tumorigenic than control cells. Paradoxically, the perlecan-deficient cells displayed increased FGF7 surface binding. However, the perlecan protein core was required for functional activation of the KGF receptor and downstream signalling. Because heparin could not substitute for perlecan, the HS chains are not critical for FGF7-mediated signalling in this cell system. These results provide the first genetic evidence that the perlecan protein core is a molecular entity implicated in FGF7 binding and activation of its receptor. PMID:11563979

  6. Cancer procoagulant: a factor X activator, tumor marker and growth factor from malignant tissue.

    PubMed

    Gordon, S G; Mielicki, W P

    1997-03-01

    Hemostatic abnormalities associated with malignant disease led to the search for and discovery of a proteolytic enzyme that activated factor X in the blood coagulation cascade. It was named cancer procoagulant (CP). CP is a cysteine proteinase that is found in malignant and fetal (human amnion-chorion) tissue; it has not been found in normally differentiated tissue. It is a calcium-dependent, Mn2+ stimulated enzyme that has enhanced activity and inhibition in a reduced environment. This review presents a complete compilation and discussion of the known chemical and enzymatic characteristics of CP as well as many purification and assay procedures. Several unique properties of these procedures are described. Some problems and controversies are highlighted in each of the sections. An immunoassay for CP as a tumor marker and some of its potential applications in the diagnosis and monitoring of cancer are reviewed. Some therapeutic implications of CP are noted in light of the observation that antibodies to CP block the metastatic seeding of lung colonies in vivo and diminish the viability of tumor cells in vitro. Finally, comments about the relationship between tissue factor and CP in the malignant cells are provided.

  7. Engineered epidermal growth factor mutants with faster binding on-rates correlate with enhanced receptor activation

    PubMed Central

    Lahti, Jennifer L.; Lui, Bertrand H.; Beck, Stayce E.; Lee, Stephen S.; Ly, Daphne P.; Longaker, Michael T.; Yang, George P.; Cochran, Jennifer R.

    2011-01-01

    Receptor tyrosine kinases (RTKs) regulate critical cell signaling pathways, yet the properties of their cognate ligands that influence receptor activation are not fully understood. There is great interest in parsing these complex ligand-receptor relationships using engineered proteins with altered binding properties. Here we focus on the interaction between two engineered epidermal growth factor (EGF) mutants and the EGF receptor (EGFR), a model member of the RTK superfamily. We found that EGF mutants with faster kinetic on-rates stimulate increased EGFR activation compared to wild-type EGF. These findings support previous predictions that faster association rates correlate with enhanced receptor activity. PMID:21439278

  8. Monocarboxylate transporter 1 contributes to growth factor-induced tumor cell migration independent of transporter activity

    PubMed Central

    Gray, Alana L.; Coleman, David T.; Shi, Runhua; Cardelli, James A.

    2016-01-01

    Tumor progression to metastatic disease contributes to the vast majority of incurable cancer. Understanding the processes leading to advanced stage cancer is important for the development of future therapeutic strategies. Here, we establish a connection between tumor cell migration, a prerequisite to metastasis, and monocarboxylate transporter 1 (MCT1). MCT1 transporter activity is known to regulate aspects of tumor progression and, as such, is a clinically relevant target for treating cancer. Knockdown of MCT1 expression caused decreased hepatocyte growth factor (HGF)-induced as well as epidermal growth factor (EGF)-induced tumor cell scattering and wound healing. Western blot analysis suggested that MCT1 knockdown (KD) hinders signaling through the HGF receptor (c-Met) but not the EGF receptor. Exogenous, membrane-permeable MCT1 substrates were not able to rescue motility in MCT1 KD cells, nor was pharmacologic inhibition of MCT1 able to recapitulate decreased cell motility as seen with MCT1 KD cells, indicating transporter activity of MCT1 was dispensable for EGF- and HGF-induced motility. These results indicate MCT1 expression, independent of transporter activity, is required for growth factor-induced tumor cell motility. The findings presented herein suggest a novel function for MCT1 in tumor progression independent of its role as a monocarboxylate transporter. PMID:27127175

  9. Activation of epidermal growth factor receptor by metal-ligand complexes decreases levels of extracellular amyloid beta peptide.

    PubMed

    Price, Katherine A; Filiz, Gulay; Caragounis, Aphrodite; Du, Tai; Laughton, Katrina M; Masters, Colin L; Sharples, Robyn A; Hill, Andrew F; Li, Qiao-Xin; Donnelly, Paul S; Barnham, Kevin J; Crouch, Peter J; White, Anthony R

    2008-01-01

    The epidermal growth factor receptor is a receptor tyrosine kinase expressed in a range of tissues and cell-types. Activation of the epidermal growth factor receptor by a number of ligands induces downstream signalling that modulates critical cell functions including growth, survival and differentiation. Abnormal epidermal growth factor receptor expression and activation is also involved in a number of cancers. In addition to its cognate ligands, the epidermal growth factor receptor can be activated by metals such as zinc (Zn) and copper (Cu). Due to the important role of these metals in a number of diseases including neurodegenerative disorders, therapeutic approaches are being developed based on the use of lipid permeable metal-complexing molecules. While these agents are showing promising results in animal models and clinical trials, little is known about the effects of metal-ligand complexes on cell signalling pathways. In this study, we investigated the effects of clioquinol (CQ)-metal complexes on activation of epidermal growth factor receptor. We show here that CQ-Cu complexes induced potent epidermal growth factor receptor phosphorylation resulting in downstream activation of extracellular signal-regulated kinase. Similar levels of epidermal growth factor receptor activation were observed with alternative lipid permeable metal-ligands including neocuproine and pyrrolidine dithiocarbamate. We found that CQ-Cu complexes induced a significant reduction in the level of extracellular Abeta1-40 in cell culture. Inhibition of epidermal growth factor receptor activation by PD153035 blocked extracellular signal-regulated kinase phosphorylation and restored Abeta1-40 levels. Activation of the epidermal growth factor receptor by CQ-Cu was mediated through up-regulation of src kinase activity by a cognate ligand-independent process involving membrane integrins. These findings provide the first evidence that metal-ligand complexes can activate the epidermal growth

  10. Vascular endothelial growth factor receptors: Molecular mechanisms of activation and therapeutic potentials

    PubMed Central

    Rahimi, Nader

    2006-01-01

    Angiogenesis-associated eye diseases are among the most common cause of blindness in the United States and worldwide. Recent advances in the development of angiogenesis-based therapies for treatment of angiogenesis-associated diseases have provided new hope in a wide variety of human diseases ranging from eye diseases to cancer. One group of growth factor receptors critically implicated in angiogenesis is vascular endothelial growth factor receptors (VEGFR), a subfamily of receptor tyrosine kinases (RTKs). VEGFR-1 and VEGFR-2 are closely related receptor tyrosine kinases and have both common and specific ligands. VEGFR-1 is a kinase-impaired RTK and its kinase activity is suppressed by a single amino acid substitution in its kinase domain and by its carboxyl terminus. VEGFR-2 is highly active kinase, stimulates a variety of signaling pathways and broad biological responses in endothelial cells. The mechanisms that govern VEGFR-2 activation, its ability to recruit signaling proteins and to undergo downregulation are highly regulated by phosphorylation activation loop tyrosines and its carboxyl terminus. Despite their differential potentials to undergo tyrosine phosphorylation and kinase activation, both VEGFR-1 and VEGFR-2 are required for normal embryonic development and pathological angiogenesis. VEGFR-1 regulates angiogenesis by mechanisms that involve ligand trapping, receptor homodimerization and heterodimerization. This review highlights recent insights into the mechanism of activation of VEGFR-1 and VEGFR-2, and focuses on the signaling pathways employed by VEGFR-1 and VEGFR-2 that regulate angiogenesis and their therapeutic potentials in angiogenesis-associated diseases. PMID:16713597

  11. Synergistic and multidimensional regulation of plasminogen activator inhibitor type 1 expression by transforming growth factor type β and epidermal growth factor

    SciTech Connect

    Song, Xiaoling; Thalacker, F.W.; Nilsen-Hamilton, Marit

    2012-04-06

    The major physiological inhibitor of plasminogen activator, type I plasminogen activator inhibitor (PAI-1), controls blood clotting and tissue remodeling events that involve cell migration. Transforming growth factor type β (TGFβ) and epidermal growth factor (EGF) interact synergistically to increase PAI-1 mRNA and protein levels in human HepG2 and mink Mv1Lu cells. Other growth factors that activate tyrosine kinase receptors can substitute for EGF. EGF and TGFβ regulate PAI-1 by synergistically activating transcription, which is further amplified by a decrease in the rate of mRNA degradation, the latter being regulated only by EGF. The combined effect of transcriptional activation and mRNA stabilization results in a rapid 2-order of magnitude increase in the level of PAI-1. TGFβ also increases the sensitivity of the cells to EGF, thereby recruiting the cooperation of EGF at lower than normally effective concentrations. The contribution of EGF to the regulation of PAI-1 involves the MAPK pathway, and the synergistic interface with the TGFβ pathway is downstream of MEK1/2 and involves phosphorylation of neither ERK1/2 nor Smad2/3. Synergism requires the presence of both Smad and AP-1 recognition sites in the promoter. This work demonstrates the existence of a multidimensional cellular mechanism by which EGF and TGFβ are able to promote large and rapid changes in PAI-1 expression.

  12. Platelet-activating factor induces ovine fetal pulmonary venous smooth muscle cell proliferation: role of epidermal growth factor receptor transactivation.

    PubMed

    Zhou, Weilin; Ibe, Basil O; Raj, J Usha

    2007-06-01

    We have previously reported that platelet-activating factor (PAF) is present in very high levels in the ovine fetal lung and circulation and that PAF serves as an important physiological vasoconstrictor of the pulmonary circulation in utero. However, it is not known whether PAF stimulates pulmonary vascular smooth muscle cell (SMC) proliferation. In this study, we used ovine fetal pulmonary venous SMCs as our model system to study the effects and mechanisms of action of PAF on SMC proliferation. We found that PAF induced SMC proliferation in a dose-dependent manner. PAF also stimulated activation of both ERK and p38 but not c-Jun NH(2) terminal kinase (JNK) mitogen-activated protein (MAP) kinase pathways. PAF (10 nM) induced phosphorylation of epidermal growth factor receptor (EGFR). Specific inhibition of EGFR by AG-1478 and by the expression of a dominant-negative EGFR mutant in SMCs attenuated PAF-stimulated cell proliferation. Inhibition of heparin-binding EGF-like growth factor (HB-EGF) release by CRM-197 and inhibition of matrix metalloproteinases (MMP) by GM-6001 abolished PAF-induced MAP kinase activation and cell proliferation. Increased alkaline phosphatase (AP) activity after PAF treatment in AP-HB-EGF fusion construct-transfected SMCs indicated that PAF induced the release of HB-EGF within 1 min. Gelatin zymography data showed that PAF stimulated MMP-2 activity and MMP-9 activity within 1 min. These results suggest that PAF promotes pulmonary vascular SMC proliferation via transactivation of EGFR through MMP activation and HB-EGF, resulting in p38 and ERK activation and that EGFR transactivation is essential for the mitogenic effect of PAF in pulmonary venous SMC. PMID:17322418

  13. Cell Surface Epidermal Growth Factor Receptors Increase Src and c-Cbl Activity and Receptor Ubiquitylation*

    PubMed Central

    Parks, Eileen E.; Ceresa, Brian P.

    2014-01-01

    There is an established role for the endocytic pathway in regulation of epidermal growth factor receptor (EGFR) signaling to downstream effectors. However, because ligand-mediated EGFR endocytosis utilizes multiple “moving parts,” dissecting the spatial versus temporal contributions has been challenging. Blocking all endocytic trafficking can have unintended effects on other receptors as well as give rise to compensatory mechanisms, both of which impact interpretation of EGFR signaling. To overcome these limitations, we used epidermal growth factor (EGF) conjugated to polystyrene beads (EGF beads). EGF beads simultaneously activate the EGFR while blocking its endocytosis and allow analysis of EGFR signaling from the plasma membrane. Human telomerase immortalized corneal epithelial (hTCEpi) cells were used to model normal epithelial cell biology. In hTCEpi cells, both cell surface and intracellular EGFRs exhibited dose-dependent increases in effector activity after 15 min of ligand stimulation, but only the serine phosphorylation of signal transducer and activator of transcription 3 (STAT3) was statistically significant when accounting for receptor phosphorylation. However, over time with physiological levels of receptor phosphorylation, cell surface receptors produced either enhanced or sustained mitogen-activated protein kinase kinase (MEK), Casitas B-lineage lymphoma (c-Cbl), and the pro-oncogene Src activity. These increases in effector communication by cell surface receptors resulted in an increase in EGFR ubiquitylation with sustained ligand incubation. Together, these data indicate that spatial regulation of EGFR signaling may be an important regulatory mechanism in receptor down-regulation. PMID:25074934

  14. Potentiation of growth factor signaling by insulin-like growth factor-binding protein-3 in breast epithelial cells requires sphingosine kinase activity.

    PubMed

    Martin, Janet L; Lin, Mike Z; McGowan, Eileen M; Baxter, Robert C

    2009-09-18

    We have investigated the mechanism underlying potentiation of epidermal growth factor receptor (EGFR) and type 1 insulin-like growth factor receptor (IGFR1) signaling by IGF-binding protein-3 (IGFBP-3) in MCF-10A breast epithelial cells, focusing on a possible involvement of the sphingosine kinase (SphK) system. IGFBP-3 potentiated EGF-stimulated EGF receptor activation and DNA synthesis, and this was blocked by inhibitors of SphK activity or small interference RNA-mediated silencing of SphK1, but not SphK2, expression. Similarly, IGFR1 phosphorylation and DNA synthesis stimulated by LR3-IGF-I (an IGF-I analog not bound by IGFBP-3), were enhanced by IGFBP-3, and this was blocked by SphK1 silencing. SphK1 expression and activity were stimulated by IGFBP-3 approximately 2-fold over 24 h. Silencing of sphingosine 1-phosphate receptor 1 (S1P1) or S1P3, but not S1P2, abolished the effect of IGFBP-3 on EGF-stimulated EGFR activation. The effects of IGFBP-3 could be reproduced with exogenous S1P or medium conditioned by cells treated with IGFBP-3, and this was also blocked by inhibition of S1P1 and S1P3. These data indicate that potentiation of growth factor signaling by IGFBP-3 in MCF-10A cells requires SphK1 activity and S1P1/S1P3, suggesting that S1P, the product of SphK activity and ligand for S1P1 and S1P3, is the "missing link" mediating IGF and EGFR transactivation and cell growth stimulation by IGFBP-3.

  15. Sphingosine-1-phosphate mediates epidermal growth factor-induced muscle satellite cell activation.

    PubMed

    Nagata, Yosuke; Ohashi, Kazuya; Wada, Eiji; Yuasa, Yuki; Shiozuka, Masataka; Nonomura, Yoshiaki; Matsuda, Ryoichi

    2014-08-01

    Skeletal muscle can regenerate repeatedly due to the presence of resident stem cells, called satellite cells. Because satellite cells are usually quiescent, they must be activated before participating in muscle regeneration in response to stimuli such as injury, overloading, and stretch. Although satellite cell activation is a crucial step in muscle regeneration, little is known of the molecular mechanisms controlling this process. Recent work showed that the bioactive lipid sphingosine-1-phosphate (S1P) plays crucial roles in the activation, proliferation, and differentiation of muscle satellite cells. We investigated the role of growth factors in S1P-mediated satellite cell activation. We found that epidermal growth factor (EGF) in combination with insulin induced proliferation of quiescent undifferentiated mouse myoblast C2C12 cells, which are also known as reserve cells, in serum-free conditions. Sphingosine kinase activity increased when reserve cells were stimulated with EGF. Treatment of reserve cells with the D-erythro-N,N-dimethylsphingosine, Sphingosine Kinase Inhibitor, or siRNA duplexes specific for sphingosine kinase 1, suppressed EGF-induced C2C12 activation. We also present the evidence showing the S1P receptor S1P2 is involved in EGF-induced reserve cell activation. Moreover, we demonstrated a combination of insulin and EGF promoted activation of satellite cells on single myofibers in a manner dependent on SPHK and S1P2. Taken together, our observations show that EGF-induced satellite cell activation is mediated by S1P and its receptor.

  16. Recombinant human epidermal growth factor precursor is a glycosylated membrane protein with biological activity.

    PubMed Central

    Mroczkowski, B; Reich, M; Chen, K; Bell, G I; Cohen, S

    1989-01-01

    NIH 3T3 cells were transfected with cDNA corresponding to human kidney prepro-epidermal growth factor (preproEGF) under control of the inducible mouse metallothionein promoter. The synthesis of recombinant human EGF precursor by these cells has provided us with a model system for analysis of the structure and activity of this precursor. In transfected cells, the precursor was present as an intrinsic 170-kilodalton membrane protein as well as a soluble protein in the extracellular medium; both forms were N glycosylated. Glycosylation of the EGF precursor was determined by (i) the direct incorporation of [3H]mannose and [3H]glucosamine, (ii) metabolic labeling in the presence or absence of glycosylation inhibitors, (iii) enzymatic cleavage of the precursor by N-glycanase or endoglycosidase II, and (iv) lectin chromatography. Recombinant human preproEGF was purified by affinity chromatography, using wheat germ lectin and antibodies to human EGF. The intact precursor was biologically active. Purified preparations of preproEGF (i) competed with 125I-labeled EGF for binding to the EGF receptor in intact fibroblast cells, (ii) activated the intrinsic tyrosine kinase activity of the EGF receptor in membrane preparations, and (iii) sustained the growth of a mouse keratinocyte cell line that is dependent on EGF for growth. These results suggest that proteolytic processing of the precursor may not be essential for its biological function. Images PMID:2789334

  17. Immunocytochemical localization of latent transforming growth factor-beta1 activation by stimulated macrophages

    NASA Technical Reports Server (NTRS)

    Chong, H.; Vodovotz, Y.; Cox, G. W.; Barcellos-Hoff, M. H.; Chatterjee, A. (Principal Investigator)

    1999-01-01

    Transforming growth factor-beta1 (TGF-beta) is secreted in a latent form consisting of mature TGF-beta noncovalently associated with its amino-terminal propeptide, which is called latency associated peptide (LAP). Biological activity depends upon the release of TGF-beta from the latent complex following extracellular activation, which appears to be the key regulatory mechanism controlling TGF-beta action. We have identified two events associated with latent TGF-beta (LTGF-beta) activation in vivo: increased immunoreactivity of certain antibodies that specifically detect TGF-beta concomitant with decreased immunoreactivity of antibodies to LAP. Macrophages stimulated in vitro with interferon-gamma and lipopolysaccharide reportedly activate LTGF-beta via cell membrane-bound protease activity. We show through dual immunostaining of paraformaldehyde-fixed macrophages that such physiological TGF-beta activation is accompanied by a loss of LAP immunoreactivity with concomitant revelation of TGF-beta epitopes. The induction of TGF-beta immunoreactivity colocalized with immunoreactive betaglycan/RIII in activated macrophages, suggesting that LTGF-beta activation occurs on the cell surface. Confocal microscopy of metabolically active macrophages incubated with antibodies to TGF-beta and betaglycan/RIII prior to fixation supported the localization of activation to the cell surface. The ability to specifically detect and localize LTGF-beta activation provides an important tool for studies of its regulation.

  18. Transient anabolic effects accompany epidermal growth factor receptor signal activation in articular cartilage in vivo

    PubMed Central

    2013-01-01

    Introduction Signals from the epidermal growth factor receptor (EGFR) have typically been considered to provide catabolic activities in articular cartilage, and accordingly have been suggested to have a causal role in osteoarthritis progression. The aim of this study was to determine in vivo roles for endogenous EGFR signal activation in articular cartilage. Methods Transgenic mice with conditional, limb-targeted deletion of the endogenous intracellular EGFR inhibitor Mig-6 were generated using CreLoxP (Mig-6-flox; Prx1Cre) recombination. Histology, histochemical staining and immunohistochemistry were used to confirm activation of EGFR signaling in the articular cartilage and joints, and to analyze phenotypic consequences of Mig-6 loss on articular cartilage morphology, proliferation, expression of progenitor cell markers, presence of chondrocyte hypertrophy and degradation of articular cartilage matrix. Results The articular cartilage of Mig-6-conditional knockout (Mig-6-cko) mice was dramatically and significantly thicker than normal articular cartilage at 6 and 12 weeks of age. Mig-6-cko articular cartilage contained a population of chondrocytes in which EGFR signaling was activated, and which were three to four times more proliferative than normal Mig-6-flox articular chondrocytes. These cells expressed high levels of the master chondrogenic regulatory factor Sox9, as well as high levels of putative progenitor cell markers including superficial zone protein (SZP), growth and differentiation factor-5 (GDF-5) and Notch1. Expression levels were also high for activated β-catenin and the transforming growth factor beta (TGF-β) mediators phospho-Smad2/3 (pSmad2/3). Anabolic effects of EGFR activation in articular cartilage were followed by catabolic events, including matrix degradation, as determined by accumulation of aggrecan cleavage fragments, and onset of hypertrophy as determined by type × collagen expression. By 16 weeks of age, the articular cartilage of

  19. Insulin, insulin-like growth factor-I, and platelet-derived growth factor activate extracellular signal-regulated kinase by distinct pathways in muscle cells.

    PubMed

    Tsakiridis, T; Tsiani, E; Lekas, P; Bergman, A; Cherepanov, V; Whiteside, C; Downey, G P

    2001-10-19

    We have investigated the signaling pathways initiated by insulin, insulin-like growth factor-1 (IGF-I), and platelet-derived growth factor (PDGF) leading to activation of the extracellular signal-regulated kinase (ERK) in L6 myotubes. Insulin but not IGF-I or PDGF-induced ERK activation was abrogated by Ras inhibition, either by treatment with the farnesyl transferase inhibitor FTP III, or by actin disassembly by cytochalasin D, previously shown to inhibit Ras activation. The protein kinase C (PKC) inhibitor bisindolylmaleimide abolished PDGF but not IGF-I or insulin-induced ERK activation. ERK activation by insulin, IGF-I, or PDGF was unaffected by the phosphatidylinositol 3-kinase inhibitor wortmannin but was abolished by the MEK inhibitor PD98059. In contrast, activation of the pathway involving phosphatidylinositol 3-kinase (PI3k), protein kinase B, and glycogen synthase kinase 3 (GSK3) was mediated similarly by all three receptors, through a PI 3-kinase-dependent but Ras- and actin-independent pathway. We conclude that ERK activation is mediated by distinct pathways including: (i) a cytoskeleton- and Ras-dependent, PKC-independent, pathway utilized by insulin, (ii) a PKC-dependent, cytoskeleton- and Ras-independent pathway used by PDGF, and (iii) a cytoskeleton-, Ras-, and PKC-independent pathway utilized by IGF-I.

  20. Stability and biological activity evaluations of PEGylated human basic fibroblast growth factor

    PubMed Central

    Hadadian, Shahin; Shamassebi, Dariush Norouzian; Mirzahoseini, Hasan; Shokrgozar, Mohamad Ali; Bouzari, Saeid; Sepahi, Mina

    2015-01-01

    Background: Human basic fibroblast growth factor (hBFGF) is a heparin-binding growth factor and stimulates the proliferation of a wide variety of cells and tissues causing survival properties and its stability and biological activity improvements have received much attention. Materials and Methods: In the present work, hBFGF produced by engineered Escherichia coli and purified by cation exchange and heparin affinity chromatography, was PEGylated under appropriate condition employing 10 kD polyethylene glycol. The PEGylated form was separated by size exclusion chromatography. Structural, biological activity, and stability evaluations were performed using Fourier transform infrared (FITR) spectroscopy, 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay and effect denaturing agent, respectively. Results: FITR spectroscopy revealed that both PEGylated and native forms had the same structures. MTT assay showed that PEGyalated form had a 30% reduced biological activity. Fluorescence spectrophotometry indicated that the PEGylated form denatured at higher concentrations of guanidine HCl (1.2 M) compared with native, which denatured at 0.8 M guanidine HCl. Conclusions: PEGylation of hBFGF makes it more stable against denaturing agent but reduces its bioactivity up to 30%. PMID:26605215

  1. Sphingosine-1-phosphate mediates epidermal growth factor-induced muscle satellite cell activation

    SciTech Connect

    Nagata, Yosuke Ohashi, Kazuya; Wada, Eiji; Yuasa, Yuki; Shiozuka, Masataka; Nonomura, Yoshiaki; Matsuda, Ryoichi

    2014-08-01

    Skeletal muscle can regenerate repeatedly due to the presence of resident stem cells, called satellite cells. Because satellite cells are usually quiescent, they must be activated before participating in muscle regeneration in response to stimuli such as injury, overloading, and stretch. Although satellite cell activation is a crucial step in muscle regeneration, little is known of the molecular mechanisms controlling this process. Recent work showed that the bioactive lipid sphingosine-1-phosphate (S1P) plays crucial roles in the activation, proliferation, and differentiation of muscle satellite cells. We investigated the role of growth factors in S1P-mediated satellite cell activation. We found that epidermal growth factor (EGF) in combination with insulin induced proliferation of quiescent undifferentiated mouse myoblast C2C12 cells, which are also known as reserve cells, in serum-free conditions. Sphingosine kinase activity increased when reserve cells were stimulated with EGF. Treatment of reserve cells with the D-erythro-N,N-dimethylsphingosine, Sphingosine Kinase Inhibitor, or siRNA duplexes specific for sphingosine kinase 1, suppressed EGF-induced C2C12 activation. We also present the evidence showing the S1P receptor S1P2 is involved in EGF-induced reserve cell activation. Moreover, we demonstrated a combination of insulin and EGF promoted activation of satellite cells on single myofibers in a manner dependent on SPHK and S1P2. Taken together, our observations show that EGF-induced satellite cell activation is mediated by S1P and its receptor. - Highlights: • EGF in combination with insulin induces proliferation of quiescent C2C12 cells. • Sphingosine kinase activity increases when reserve cells are stimulated with EGF. • EGF-induced activation of reserve cells is dependent on sphingosine kinase and ERK. • The S1P receptor S1P2 is involved in EGF-induced reserve cell activation. • EGF-induced reserve cell activation is mediated by S1P and its

  2. CSK negatively regulates nerve growth factor induced neural differentiation and augments AKT kinase activity

    SciTech Connect

    Dey, Nandini . E-mail: Don_Durden@oz.ped.emory.edu

    2005-07-01

    Src family kinases are involved in transducing growth factor signals for cellular differentiation and proliferation in a variety of cell types. The activity of all Src family kinases (SFKs) is controlled by phosphorylation at their C-terminal 527-tyrosine residue by C-terminal SRC kinase, CSK. There is a paucity of information regarding the role of CSK and/or specific Src family kinases in neuronal differentiation. Pretreatment of PC12 cells with the Src family kinase inhibitor, PP1, blocked NGF-induced activation of SFKs and obliterated neurite outgrowth. To confirm a role for CSK and specific isoforms of SFKs in neuronal differentiation, we overexpressed active and catalytically dead CSK in the rat pheochromocytoma cell line, PC12. CSK overexpression caused a profound inhibition of NGF-induced activation of FYN, YES, RAS, and ERK and inhibited neurite outgrowth, NGF-stimulated integrin-directed migration and blocked the NGF-induced conversion of GDP-RAC to its GTP-bound active state. CSK overexpression markedly augmented the activation state of AKT following NGF stimulation. In contrast, kinase-dead CSK augmented the activation of FYN, RAS, and ERK and increased neurite outgrowth. These data suggest a distinct requirement for CSK in the regulation of NGF/TrkA activation of RAS, RAC, ERK, and AKT via the differential control of SFKs in the orchestration of neuronal differentiation.

  3. Exogenous nerve growth factor stimulates choline acetyltransferase activity in aging Fischer 344 male rats.

    PubMed

    Williams, L R

    1991-01-01

    The effect of age and exogenous nerve growth factor (NGF) infusion on choline acetyltransferase (ChAT) specific activity is examined in microdissections of cerebral and hippocampal cortices, and the cholinergic nuclei of the medial septum and diagonal band of Broca (MS/DB), the nucleus basalis magnocellularis (NBM), and striatum of Fischer 344 male rats. Significant, 20% losses in ChAT activity are found in the MS/DB and striatum of 24-month-old rats (n = 21) compared to 4-month-old animals, but there is no apparent loss of enzyme activity in the NBM. Loss of ChAT activity in the MS/DB is only observed in animals older than 19 months of age, while a striatal deficit is found in animals older than 7 months. Treatment for 2 weeks with NGF at 1.2 micrograms/day results in significant 70% increases of ChAT activity in the MS/DB and striatum of 24-month-old rats compared to untreated and vehicle-treated 4-month-old rats, but does not stimulate activity in the NBM. Sensitivity of ChAT activity in the MS/DB and striatum to exogenous NGF increases with age. These experiments indicate that in the MS/DB, NBM, and striatum of Fischer 344 male rat there is an age-associated, differential regulation of ChAT enzyme activity and sensitivity to exogenous NGF.

  4. Transforming growth factor-1 promotes the transcriptional activation of plasminogen activator inhibitor type 1 in carcinoma-associated fibroblasts.

    PubMed

    Zhu, Yu; Yin, Wan-Le; Ba, Yu-Feng; Tian, Lin; Gu, Zhi-Qiang; Zhang, Ming-Sheng; Zhong, Chu-Nan

    2012-11-01

    Carcinoma-associated fibroblasts (CAFs) play a pivotal role in promoting the growth, invasion and metastasis of tumor cells. However, to date little is known about the oncogenic mechanisms of CAFs. This study aimed to identify the microenvironmental factors involved in tumor development and progression directed by CAFs in liver metastases. Tissue samples collected from 20 patients with colorectal liver metastases were used in this study. Histological and morphological characterization of the samples was performed using hybridization and immunohistological assays. The mRNA expression of α-smooth muscle actin (α-SMA) was measured by northern blotting. The expression of plasminogen activator inhibitor type 1 (PAI-1) was measured by enzyme-linked immunosorbent assay (ELISA). As a result, co-expression of Thy-1 (CD90) and α-SMA was identified in CAFs, while normal liver samples were negative for α-SMA and Thy-1. Compared with epidermal growth factor (EGF) and tumor necrosis factor (TNF) incubation, the expression of α-SMA increased significantly following transforming growth factor-1 (TGF-1) incubation (P<0.05), while platelet-derived growth factor (PDGF) caused a significant suppression of α-SMA expression (P<0.05). PAI-1 expression was significantly lower in unstimulated fibroblasts compared to TGF-1-treated fibroblasts (P<0.01). The levels of PAI-1 transcription were significantly higher in CAFs from the patient samples compared with the healthy controls. Taken together, our findings suggest that CAFs may be important in migration, matrix degradation, invasion and angiogenesis of tumors, and TGF-1 may promote the activation of PAI-1 transcription in CAFs.

  5. Sustained activation of fibroblast transforming growth factor-beta/Smad signaling in a murine model of scleroderma.

    PubMed

    Takagawa, Shinsuke; Lakos, Gabriella; Mori, Yasuji; Yamamoto, Toshiyuki; Nishioka, Kiyoshi; Varga, John

    2003-07-01

    Transforming growth factor-beta is responsible for triggering a cascade of events leading to fibrosis in scleroderma. The Smads are intracellular signal transducers recently shown to mediate fibroblast activation and other profibrotic responses elicited by transforming growth factor-betain vitro. To understand better the involvement of Smads in the pathogenesis of fibrosis, we examined Smad expression and activation in situ in a murine model of scleroderma. Bleomycin injections induced striking dermal infiltration with macrophages by 3 d, and progressive fibrosis by 2 wk. Infiltrating macrophages and resident fibroblasts expressed Smad3, the positive mediator for transforming growth factor-beta responses. Importantly, in bleomycin-injected skin, fibroblasts showed predominantly nuclear localization of Smad3 and intense staining for phospho-Smad2/3. Furthermore, phosphorylated Smad2/3 in fibroblasts was detected even after the resolution of inflammation. Expression of Smad7, the endogenous inhibitor of transforming growth factor-beta/Smad signaling, was strongly induced in dermal cells by transforming growth factor-beta, but not by bleomycin injections. Collectively, these results indicate that bleomycin-induced murine scleroderma is associated with rapid and sustained induction of transforming growth factor-beta/Smad signaling in resident dermal fibroblasts. Despite apparent activation of the intracellular transforming growth factor-beta signaling pathway in the lesional dermis, the expression of transforming growth factor-beta-inducible Smad7 was not upregulated. In light of the critical function of Smad7 as an endogenous inhibitor of Smad signaling that restricts the duration and magnitude of transforming growth factor-beta responses, and as a mediator of apoptosis, relative Smad7 deficiency observed in the present studies may account for sustained activation of transforming growth factor-beta/Smad signaling in lesional tissues. These findings raise the

  6. Structure-Activity Relationship of Indole-Tethered Pyrimidine Derivatives that Concurrently Inhibit Epidermal Growth Factor Receptor and Other Angiokinases

    PubMed Central

    Song, Jiho; Yoo, Jakyung; Kwon, Ara; Kim, Doran; Nguyen, Hong Khanh; Lee, Bong-Yong; Suh, Wonhee; Min, Kyung Hoon

    2015-01-01

    Antiangiogenic agents have been widely investigated in combination with standard chemotherapy or targeted cancer agents for better management of advanced cancers. Therapeutic agents that concurrently inhibit epidermal growth factor receptor and other angiokinases could be useful alternatives to combination therapies for epidermal growth factor receptor-dependent cancers. Here, we report the synthesis of an indole derivative of pazopanib using a bioisosteric replacement strategy, which was designated MKP101. MKP101 inhibited not only the epidermal growth factor receptor with an IC50 value of 43 nM but also inhibited angiokinases as potently as pazopanib. In addition, MKP101 effectively inhibited vascular endothelial growth factor-induced endothelial proliferation, tube formation, migration of human umbilical vein endothelial cells and proliferation of HCC827, an epidermal growth factor receptor-addicted cancer cell line. A docking model of MKP101 and the kinase domain of the epidermal growth factor receptor was generated to predict its binding mode, and validated by synthesizing and evaluating MKP101 derivatives. Additionally, a study of structure-activity relationships of indolylamino or indolyloxy pyrimidine analogues derived from MKP101 demonstrated that selectivity for epidermal growth factor receptor and other angiokinases, especially vascular endothelial growth factor receptor 2 depends on the position of substituents on pyrimidine and the type of link between pyrimidine and the indole moiety. We believe that this study could provide a basis for developing angiokinase inhibitors having high affinity for the epidermal growth factor receptor, from the pyrimidine scaffold. PMID:26401847

  7. Phosphatidylinositol-4,5-bisphosphate regulates epidermal growth factor receptor activation

    PubMed Central

    Michailidis, Ioannis E.; Rusinova, Radda; Georgakopoulos, Anastasios; Chen, Yibang; Iyengar, Ravi; Robakis, Nikolaos K.; Logothetis, Diomedes E.; Baki, Lia

    2012-01-01

    Phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2 or PIP2] is a direct modulator of a diverse array of proteins in eukaryotic cells. The functional integrity of transmembrane proteins, such as ion channels and transporters, is critically dependent on specific interactions with PIP2 and other phosphoinositides. Here, we report a novel requirement for PIP2 in the activation of the epidermal growth factor receptor (EGFR). Down-regulation of PIP2 levels either via pharmacological inhibition of PI kinase activity, or via manipulation of the levels of the lipid kinase PIP5K1α and the lipid phosphatase synaptojanin, reduced EGFR tyrosine phosphorylation, whereas up-regulation of PIP2 levels via overexpression of PIP5K1α had the opposite effect. A cluster of positively charged residues in the juxtamembrane domain (basic JD) of EGFR is likely to mediate binding of EGFR to PIP2 and PIP2-dependent regulation of EGFR activation. A peptide mimicking the EGFR juxtamembrane domain that was assayed by surface plasmon resonance displayed strong binding to PIP2. Neutralization of positively charged amino acids abolished EGFR/PIP2 interaction in the context of this peptide and down-regulated epidermal growth factor (EGF)-induced EGFR autophosphorylation and EGF-induced EGFR signaling to ion channels in the context of the full-length receptor. These results suggest that EGFR activation and downstream signaling depend on interactions of EGFR with PIP2 and point to the basic JD’s critical involvement in these interactions. The addition of this very different class of membrane proteins to ion channels and transporters suggests that PIP2 may serve as a general modulator of the activity of many diverse eukaryotic transmembrane proteins through their basic JDs. PMID:21107857

  8. Phosphatidylinositol kinase is activated in membranes derived from cells treated with epidermal growth factor.

    PubMed Central

    Walker, D H; Pike, L J

    1987-01-01

    The ability of epidermal growth factor (EGF) to stimulate phosphatidylinositol (PtdIns) kinase activity in A431 cells was examined. The incorporation of 32P from [gamma-32P]ATP into PtdIns by A431 membranes was increased in membranes prepared from cells that had been pretreated with EGF. Demonstration of a stimulation of the PtdIns kinase activity by EGF required the use of subconfluent cultures and was dependent on the inclusion of protease inhibitors in the buffers used to prepare the membranes. Stimulation of the PtdIns kinase activity was rapid. The activation peaked 2 min after the addition of EGF and declined slowly thereafter. Half-maximal stimulation of the PtdIns kinase occurred at 7 nM EGF. Kinetic analyses of the reaction indicated that treatment of the cells with EGF resulted in a decrease in the Km for PtdIns with no change in the Vmax. The kinetic parameters for the utilization of ATP were unchanged in the EGF-treated membranes compared to the control membranes. Pretreatment of the cells with the phorbol ester phorbol 12-myristate 13-acetate blocked the ability of EGF to stimulate PtdIns kinase activity. These findings demonstrate that a PtdIns kinase activity in A431 cells is regulated by EGF and provide a good system for examining the mechanism by which EGF stimulates the activity of this intracellular enzyme. PMID:2823265

  9. Redox-mediated activation of latent transforming growth factor-beta 1

    NASA Technical Reports Server (NTRS)

    Barcellos-Hoff, M. H.; Dix, T. A.; Chatterjee, A. (Principal Investigator)

    1996-01-01

    Transforming growth factor beta 1 (TGF beta) is a multifunctional cytokine that orchestrates response to injury via ubiquitous cell surface receptors. The biological activity of TGF beta is restrained by its secretion as a latent complex (LTGF beta) such that activation determines the extent of TGF beta activity during physiological and pathological events. TGF beta action has been implicated in a variety of reactive oxygen-mediated tissue processes, particularly inflammation, and in pathologies such as reperfusion injury, rheumatoid arthritis, and atherosclerosis. It was recently shown to be rapidly activated after in vivo radiation exposure, which also generates reactive oxygen species (ROS). In the present studies, the potential for redox-mediated LTGF beta activation was investigated using a cell-free system in which ROS were generated in solution by ionizing radiation or metal ion-catalyzed ascorbate reaction. Irradiation (100 Gray) of recombinant human LTGF beta in solution induced 26% activation compared with that elicited by standard thermal activation. Metal-catalyzed ascorbate oxidation elicited extremely efficient recombinant LTGF beta activation that matched or exceeded thermal activation. The efficiency of ascorbate activation depended on ascorbate concentrations and the presence of transition metal ions. We postulate that oxidation of specific amino acids in the latency-conferring peptide leads to a conformation change in the latent complex that allows release of TGF beta. Oxidative activation offers a novel route for the involvement of TGF beta in tissue processes in which ROS are implicated and endows LTGF beta with the ability to act as a sensor of oxidative stress and, by releasing TGF beta, to function as a signal for orchestrating the response of multiple cell types. LTGF beta redox sensitivity is presumably directed toward recovery of homeostasis; however, oxidation may also be a mechanism of LTGF beta activation that can be deleterious during

  10. Release of basic fibroblast growth factor-heparan sulfate complexes from endothelial cells by plasminogen activator-mediated proteolytic activity

    PubMed Central

    1990-01-01

    Cultured bovine capillary endothelial (BCE) cells synthesize heparan sulfate proteoglycans (HSPG), which are both secreted into the culture medium and deposited in the cell layer. The nonsoluble HSPGs can be isolated as two predominant species: a larger 800-kD HSPG, which is recovered from preparations of extracellular matrix, and a 250-kD HSPG, which is solubilized by nonionic detergent extraction of the cells. Both HSPG species bind bFGF. 125I-bFGF bound to BCE cell cultures is readily released by either heparinase or plasmin. When released by plasmin, the growth factor is recovered from the incubation medium as a complex with the partly degraded high molecular mass HSPG. Endogenous bFGF activity is released by a proteolytic treatment of cultured BCE cells. The bFGF-binding HSPGs are also released when cultures are incubated with the inactive proenzyme plasminogen. Under such experimental conditions, the release of the extracellular proteoglycans can be enhanced by treating the cells either with bFGF, which increases the plasminogen activating activity expressed by the cells, or decreased by treating the cells with transforming growth factor beta, which decreases the plasminogen activating activity of the cells. Specific immune antibodies raised against bovine urokinase also block the release of HSPG from BCE cell cultures. We propose that this plasminogen activator-mediated proteolysis provides a mechanism for the release of biologically active bFGF-HSPG complexes from the extracellular matrix and that bFGF release can be regulated by the balance between factors affecting the pericellular proteolytic activity. PMID:2137829

  11. Immunohistochemical detection of active transforming growth factor-beta in situ using engineered tissue

    NASA Technical Reports Server (NTRS)

    Barcellos-Hoff, M. H.; Ehrhart, E. J.; Kalia, M.; Jirtle, R.; Flanders, K.; Tsang, M. L.; Chatterjee, A. (Principal Investigator)

    1995-01-01

    The biological activity of transforming growth factor-beta 1 (TGF-beta) is governed by dissociation from its latent complex. Immunohistochemical discrimination of active and latent TGF-beta could provide insight into TGF-beta activation in physiological and pathological processes. However, evaluation of immunoreactivity specificity in situ has been hindered by the lack of tissue in which TGF-beta status is known. To provide in situ analysis of antibodies to differentiate between these functional forms, we used xenografts of human tumor cells modified by transfection to overexpress latent TGF-beta or constitutively active TGF-beta. This comparison revealed that, whereas most antibodies did not differentiate between TGF-beta activation status, the immunoreactivity of some antibodies was activation dependent. Two widely used peptide antibodies to the amino-terminus of TGF-beta, LC(1-30) and CC(1-30) showed marked preferential immunoreactivity with active TGF-beta versus latent TGF-beta in cryosections. However, in formalin-fixed, paraffin-embedded tissue, discrimination of active TGF-beta by CC(1-30) was lost and immunoreactivity was distinctly extracellular, as previously reported for this antibody. Similar processing-dependent extracellular localization was found with a neutralizing antibody raised to recombinant TGF-beta. Antigen retrieval recovered cell-associated immunoreactivity of both antibodies. Two antibodies to peptides 78-109 showed mild to moderate preferential immunoreactivity with active TGF-beta only in paraffin sections. LC(1-30) was the only antibody tested that discriminated active from latent TGF-beta in both frozen and paraffin-embedded tissue. Thus, in situ discrimination of active versus latent TGF-beta depends on both the antibody and tissue preparation. We propose that tissues engineered to express a specific form of a given protein provide a physiological setting in which to evaluate antibody reactivity with specific functional forms of a

  12. MEK-ERK Pathway Modulation Ameliorates Pulmonary Fibrosis Associated with Epidermal Growth Factor Receptor Activation

    PubMed Central

    Madala, Satish K.; Schmidt, Stephanie; Davidson, Cynthia; Ikegami, Machiko; Wert, Susan

    2012-01-01

    Pulmonary fibrosis remains a significant public health burden with no proven therapies. The mitogen-activated protein kinase (MAPK)/MAPK kinase (MEK)/extracellular signal–regulated kinase (ERK) signaling cascade is a major pathway controlling cellular processes associated with fibrogenesis, including growth, proliferation, and survival. Activation of the MAPK/ERK pathway is detected in the lungs of human fibrosis samples; however, the effect of modulating the pathway in vivo is unknown. Overexpression of transforming growth factor (TGF)-α in the lung epithelium of transgenic mice causes a progressive pulmonary fibrosis associated with increased MEK/ERK activation localized primarily in mesenchymal cells. To determine the role of the MEK pathway in the induction of TGF-α–induced lung fibrosis, TGF-α was overexpressed for 4 weeks while mice were simultaneously treated with the specific MEK inhibitor, ARRY-142886 (ARRY). Treatment with ARRY prevented increases in lung cell proliferation and total lung collagen, attenuated production of extracellular matrix genes, and protected mice from changes in lung function. ARRY administered as a rescue treatment after fibrosis was already established inhibited fibrosis progression, as assessed by lung histology, changes in body weights, extracellular matrix gene expression, and lung mechanics. These findings demonstrate that MEK inhibition prevents progression of established fibrosis in the TGF-α model, and provides proof of concept of targeting the MEK pathway in fibrotic lung disease. PMID:22021337

  13. Neuroprotective activity of peripherally administered liver growth factor in a rat model of Parkinson's disease.

    PubMed

    Gonzalo-Gobernado, Rafael; Calatrava-Ferreras, Lucía; Reimers, Diana; Herranz, Antonio Sánchez; Rodríguez-Serrano, Macarena; Miranda, Cristina; Jiménez-Escrig, Adriano; Díaz-Gil, Juan José; Bazán, Eulalia

    2013-01-01

    Liver growth factor (LGF) is a hepatic mitogen purified some years ago that promotes proliferation of different cell types and the regeneration of damaged tissues, including brain tissue. Considering the possibility that LGF could be used as a therapeutic agent in Parkinson's disease, we analyzed its potential neuroregenerative and/or neuroprotective activity when peripherally administered to unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rats. For these studies, rats subjected to nigrostriatal lesions were treated intraperitoneally twice a week with LGF (5 microg/rat) for 3 weeks. Animals were sacrificed 4 weeks after the last LGF treatment. The results show that LGF stimulates sprouting of tyrosine hydroxylase-positive terminals and increases tyrosine hydroxylase and dopamine transporter expression, as well as dopamine levels in the denervated striatum of 6-OHDA-lesioned rats. In this structure, LGF activates microglia and raises tumor necrosis factor-alpha protein levels, which have been reported to have a role in neuroregeneration and neuroprotection. Besides, LGF stimulates the phosphorylation of MAPK/ERK1/2 and CREB, and regulates the expression of proteins which are critical for cell survival such as Bcl2 and Akt. Because LGF partially protects dopamine neurons from 6-OHDA neurotoxicity in the substantia nigra, and reduces motor deficits in these animals, we propose LGF as a novel factor that may be useful in the treatment of Parkinson's disease.

  14. Autocrine and/or paracrine insulin-like growth factor-I activity in skeletal muscle

    NASA Technical Reports Server (NTRS)

    Adams, Gregory R.

    2002-01-01

    Similar to bone, skeletal muscle responds and adapts to changes in loading state via mechanisms that appear to be intrinsic to the muscle. One of the mechanisms modulating skeletal muscle adaptation it thought to involve the autocrine and/or paracrine production of insulinlike growth factor-I. This brief review outlines components of the insulinlike growth factor-I system as it relates to skeletal muscle and provides the rationale for the theory that insulinlike growth factor-I is involved with muscle adaptation.

  15. Diosgenin attenuates hepatic stellate cell activation through transforming growth factor-β/Smad signaling pathway

    PubMed Central

    Xie, Wei-Lin; Jiang, Rong; Shen, Xiao-Lu; Chen, Zhi-Yu; Deng, Xiao-Ming

    2015-01-01

    Activation of hepatic stellate cells (HSC) plays a pivotal role in the development of hepatic fibrosis. Transforming growth factor-β1 (TGF-β1) is considered to be the main stimuli factor responsible for the activation of HSC. Diosgenin is a steroidal saponin found in several plants including Solanum and Dioscorea species, and it inhibited high glucose-induced renal tubular fibrosis. However, the effects of diosgenin against hepatic fibrosis remain elusive. Therefore, in this study, we investigated the effects of diosgenin on TGF-β1-induced HSCs and elucidate the possible mechanism of its anti-fibrotic effect. Our results demonstrated that diosgenin inhibited TGF-β1-induced HSC proliferation, reduced the expression of collagen I and α-smooth muscle actin (α-SMA), as well as the expression of TGF-β receptor I (TGF-β RI) and II. Moreover, diosgenin suppressed TGF-β1-induced phosphorylation of Smad3 in HSCs. In conclusion, our data demonstrate that diosgenin inhibited HSC-T6 cell proliferation and activation, at least in part, via the TGF-β1/Smad signaling pathway. These results provide that diosgenin may have potential to treat liver fibrosis. PMID:26884947

  16. Diosgenin attenuates hepatic stellate cell activation through transforming growth factor-β/Smad signaling pathway.

    PubMed

    Xie, Wei-Lin; Jiang, Rong; Shen, Xiao-Lu; Chen, Zhi-Yu; Deng, Xiao-Ming

    2015-01-01

    Activation of hepatic stellate cells (HSC) plays a pivotal role in the development of hepatic fibrosis. Transforming growth factor-β1 (TGF-β1) is considered to be the main stimuli factor responsible for the activation of HSC. Diosgenin is a steroidal saponin found in several plants including Solanum and Dioscorea species, and it inhibited high glucose-induced renal tubular fibrosis. However, the effects of diosgenin against hepatic fibrosis remain elusive. Therefore, in this study, we investigated the effects of diosgenin on TGF-β1-induced HSCs and elucidate the possible mechanism of its anti-fibrotic effect. Our results demonstrated that diosgenin inhibited TGF-β1-induced HSC proliferation, reduced the expression of collagen I and α-smooth muscle actin (α-SMA), as well as the expression of TGF-β receptor I (TGF-β RI) and II. Moreover, diosgenin suppressed TGF-β1-induced phosphorylation of Smad3 in HSCs. In conclusion, our data demonstrate that diosgenin inhibited HSC-T6 cell proliferation and activation, at least in part, via the TGF-β1/Smad signaling pathway. These results provide that diosgenin may have potential to treat liver fibrosis. PMID:26884947

  17. Activation of Cardiac Fibroblast Growth Factor Receptor 4 Causes Left Ventricular Hypertrophy.

    PubMed

    Grabner, Alexander; Amaral, Ansel P; Schramm, Karla; Singh, Saurav; Sloan, Alexis; Yanucil, Christopher; Li, Jihe; Shehadeh, Lina A; Hare, Joshua M; David, Valentin; Martin, Aline; Fornoni, Alessia; Di Marco, Giovana Seno; Kentrup, Dominik; Reuter, Stefan; Mayer, Anna B; Pavenstädt, Hermann; Stypmann, Jörg; Kuhn, Christian; Hille, Susanne; Frey, Norbert; Leifheit-Nestler, Maren; Richter, Beatrice; Haffner, Dieter; Abraham, Reimar; Bange, Johannes; Sperl, Bianca; Ullrich, Axel; Brand, Marcus; Wolf, Myles; Faul, Christian

    2015-12-01

    Chronic kidney disease (CKD) is a worldwide public health threat that increases risk of death due to cardiovascular complications, including left ventricular hypertrophy (LVH). Novel therapeutic targets are needed to design treatments to alleviate the cardiovascular burden of CKD. Previously, we demonstrated that circulating concentrations of fibroblast growth factor (FGF) 23 rise progressively in CKD and induce LVH through an unknown FGF receptor (FGFR)-dependent mechanism. Here, we report that FGF23 exclusively activates FGFR4 on cardiac myocytes to stimulate phospholipase Cγ/calcineurin/nuclear factor of activated T cell signaling. A specific FGFR4-blocking antibody inhibits FGF23-induced hypertrophy of isolated cardiac myocytes and attenuates LVH in rats with CKD. Mice lacking FGFR4 do not develop LVH in response to elevated FGF23, whereas knockin mice carrying an FGFR4 gain-of-function mutation spontaneously develop LVH. Thus, FGF23 promotes LVH by activating FGFR4, thereby establishing FGFR4 as a pharmacological target for reducing cardiovascular risk in CKD.

  18. PTEN mutation and epidermal growth factor receptor activation regulate vascular endothelial growth factor (VEGF) mRNA expression in human glioblastoma cells by transactivating the proximal VEGF promoter.

    PubMed

    Pore, Nabendu; Liu, Shuang; Haas-Kogan, Daphne A; O'Rourke, Donald M; Maity, Amit

    2003-01-01

    Our previous work showed that, compared with parental U87MG human glioblastoma cells, vascular endothelial growth factor (VEGF) mRNA levels are decreased in U87/T691, a derivative line in which epidermal growth factor receptor (EGFR) signaling is inhibited by introduction of a truncated p185(Neu) protein (A. Maity et al., Cancer Res., 60: 5879-5886, 2000). The effect of EGFR activation on VEGF was mediated at the level of transcription via a phosphatidylinositol 3'-kinase (PI3K)-dependent pathway. In the current study we investigated the effect of PTEN, a negative regulator of PI3K signaling commonly mutated in glioblastoma cells, on VEGF expression. Several glioblastoma cell lines containing mutant PTEN, including U87MG, U87/T691, and U251MG, were infected with adenovirus expressing wild-type PTEN. This led to a decrease in the levels of both VEGF mRNA and phosphorylated Akt, a marker for PI3K activation. Treatment of U87MG cells with LY294002, a PI3K inhibitor, or cotransfection with a vector expressing wild-type PTEN decreased VEGF promoter activity using reporters containing either 1.5 kb of the promoter or a fragment extending from -88 to +54 bp. Activity of the -88/+54 VEGF promoter was down-regulated by dominant negative Akt and up-regulated by constitutively active myristoylated Akt. Introduction of wild-type PTEN and pharmacological inhibition of EGFR decreased VEGF mRNA expression and VEGF promoter activity in U87MG cells to a greater extent that did either manipulation by itself. Therefore, in human glioblastoma cells, PTEN mutation can cooperate with EGFR activation to increase VEGF mRNA levels by transcriptionally up-regulating the proximal VEGF promoter via the PI3K/Akt pathway.

  19. Synthesis and structure-activity study of myxoma virus growth factor

    SciTech Connect

    Lin, Yao-Zhong; Ke, Xiao-Hong; Tam, J.P. )

    1991-04-02

    Myxoma virus growth factor (MGF) is an 85-residue peptide derived from the gene product of a DNA tumor virus that infects rabbits. The carboxyl domain of MGF possesses about 40% sequence homology with the epidermal growth factor (EGF). This EGF-like domain covering residues 30-83 was synthesized and found to possess putative activities of EGF. It was, however, about 200-fold less active than EGF in the competitive binding of human EGF receptor in A431 cells and the stimulation of ({sup 3}H)thymidine uptake in NRK 49F cells. MGF(30-83) is a basic and a hydrophobic peptide rich in {beta}-sheet structure. These features in MGF tend to promote aggregation, leading to precipitation even in strongly denaturing solutions. Thus, the refolding of MGF was achieved with difficulty and resulted in low yield. To increase the synthetic yield of MGF(30-83), a cluster of acidic amino acids was added to the NH{sub 2}-terminus of MGF(30-83). This approach was found to be effective in minimizing the refolding difficulties and allowed accessibility to the synthesis of analogues in this class of compounds. The relationships of structure and function of MGF were studied by using analogues with point substitution by the corresponding D-amino acid or by Ala at position 44 or 52 and analogues with deletion of basic residues from the amino terminus. Modifications of both the receptor contact and the structural residues greatly reduced the potency of MGF(30-83), and the overall result correlated well with the known structure-activity of the EGF family.

  20. Immobilized epidermal growth factor stimulates persistent, directed keratinocyte migration via activation of PLCγ1.

    PubMed

    Kim, Chloe S; Mitchell, Isaiah P; Desotell, Anthony W; Kreeger, Pamela K; Masters, Kristyn S

    2016-07-01

    Epidermal growth factor (EGF) is a critical element in dermal repair, but EGF-containing wound dressings have not been successful clinically. However, these dressings have delivered only soluble EGF, and the native environment provides both soluble and matrix-bound EGF. To address our hypothesis that tethered EGF can stimulate cell behaviors not achievable with soluble EGF, we examined single-cell movement and signaling in human immortalized HaCaT keratinocytes treated with soluble or immobilized EGF. Although both EGF treatments increased collective sheet displacement and individual cell speed, only cells treated with immobilized EGF exhibited directed migration, as well as 2-fold greater persistence compared with soluble EGF. Immunofluorescence showed altered EGF receptor (EGFR) trafficking, where EGFR remained membrane-localized in the immobilized EGF condition. Cells treated with soluble EGF demonstrated higher phosphorylated ERK1/2, and cells on immobilized EGF exhibited higher pPLCγ1, which was localized at the leading edge. Treatment with U0126 inhibited migration in both conditions, demonstrating that ERK1/2 activity was necessary but not responsible for the observed differences. In contrast, PLCγ1 inhibition with U73122 significantly decreased persistence on immobilized EGF. Combined, these results suggest that immobilized EGF increases collective keratinocyte displacement via an increase in single-cell migration persistence resulting from altered EGFR trafficking and PLCγ1 activation.-Kim, C. S., Mitchell, I. P., Desotell, A. W., Kreeger, P. K., Masters, K. S. Immobilized epidermal growth factor stimulates persistent, directed keratinocyte migration via activation of PLCγ1.

  1. Immobilized epidermal growth factor stimulates persistent, directed keratinocyte migration via activation of PLCγ1.

    PubMed

    Kim, Chloe S; Mitchell, Isaiah P; Desotell, Anthony W; Kreeger, Pamela K; Masters, Kristyn S

    2016-07-01

    Epidermal growth factor (EGF) is a critical element in dermal repair, but EGF-containing wound dressings have not been successful clinically. However, these dressings have delivered only soluble EGF, and the native environment provides both soluble and matrix-bound EGF. To address our hypothesis that tethered EGF can stimulate cell behaviors not achievable with soluble EGF, we examined single-cell movement and signaling in human immortalized HaCaT keratinocytes treated with soluble or immobilized EGF. Although both EGF treatments increased collective sheet displacement and individual cell speed, only cells treated with immobilized EGF exhibited directed migration, as well as 2-fold greater persistence compared with soluble EGF. Immunofluorescence showed altered EGF receptor (EGFR) trafficking, where EGFR remained membrane-localized in the immobilized EGF condition. Cells treated with soluble EGF demonstrated higher phosphorylated ERK1/2, and cells on immobilized EGF exhibited higher pPLCγ1, which was localized at the leading edge. Treatment with U0126 inhibited migration in both conditions, demonstrating that ERK1/2 activity was necessary but not responsible for the observed differences. In contrast, PLCγ1 inhibition with U73122 significantly decreased persistence on immobilized EGF. Combined, these results suggest that immobilized EGF increases collective keratinocyte displacement via an increase in single-cell migration persistence resulting from altered EGFR trafficking and PLCγ1 activation.-Kim, C. S., Mitchell, I. P., Desotell, A. W., Kreeger, P. K., Masters, K. S. Immobilized epidermal growth factor stimulates persistent, directed keratinocyte migration via activation of PLCγ1. PMID:27025961

  2. INSULIN INDUCED EPIDERMAL GROWTH FACTOR ACTIVATION IN VASCULAR SMOOTH MUSCLE CELLS IS ADAM-DEPENDENT

    PubMed Central

    Roztocil, Elisa; Nicholl, Suzanne M.; Davies, Mark G.

    2008-01-01

    Background With the rise in metabolic syndrome, understanding the role of insulin signaling within the cells of vasculature has become more important but yet remains poorly defined. The study examines the role of insulin actions on a pivotal cross-talk receptor, Epidermal Growth Factor Receptor (EGFR). EGFR is transactivated by both G-protein-coupled receptors and receptor linked tyrosine kinases and is key to many of their responses. Objective To determine the pathway of EGFR transactivation by insulin in human coronary smooth muscle cells (VSMC) Methods VSMC were cultured in vitro. Assays of EGFR phosphorylation were examined in response to insulin in the presence and absence of the plasmin inhibitors (e-aminocaproic acid and aprotinin) matrix metalloprotease (MMP) inhibitor GM6001, the ADAM (A Disintegrin And Metalloproteinase Domain) inhibitors TAPI-0 and TAPI-1, Heparin binding epidermal growth factor (HB-EGF) inhibitor, CRM197, HB-EGF inhibitory antibodies, EGF inhibitory antibodies and the EGFR inhibitor AG1478. Results Insulin induced time-dependent EGFR phosphorylation, which was inhibited by AG1478 in a concentration dependent manner. Application of the plasmin inhibitors did not block the response. EGFR phosphorylation by insulin was blocked by inhibition of MMP activity and the ligand HB-EGF. The presence of the ADAM inhibitors, TAPI-0 and TAPI-1 significantly decreased EGFR activation. EGFR phosphorylation by EGF was not interrupted by inhibition of plasmin, MMPs TAPIs, or HB-EGF. Direct blockade of the EGFR prevented activation by both insulin and EGF. Conclusion Insulin can induce transactivation of EGFR by an ADAM-mediated, HB-EGF dependent process. This is the first description of crosstalk via ADAM between insulin and EGFR in vascular SMC. Targeting a pivotal cross-talk receptor such as EGFR, which can be transactivated by both G-protein-coupled receptors and receptor tyrosine kinases is an attractive molecular target. PMID:18656632

  3. Constitutive asymmetric dimerization drives oncogenic activation of epidermal growth factor receptor carboxyl-terminal deletion mutants

    PubMed Central

    Park, Angela K.J.; Francis, Joshua M.; Park, Woong-Yang; Park, Joon-Oh; Cho, Jeonghee

    2015-01-01

    Genomic alterations targeting the Epidermal Growth Factor Receptor (EGFR) gene have been strongly associated with cancer pathogenesis. The clinical effectiveness of EGFR targeted therapies, including small molecules directed against the kinase domain such as gefitinib, erlotinib and afatinib, have been proven successful in treating non-small cell lung cancer patients with tumors harboring EGFR kinase domain mutations. Recent large-scale genomic studies in glioblastoma and lung cancer have identified an additional class of oncogenic mutations caused by the intragenic deletion of carboxy-terminal coding regions. Here, we report that combinations of exonic deletions of exon 25 to 28 lead to the oncogenic activation of EGF receptor in the absence of ligand and consequent cellular transformation, indicating a significant role of C-terminal domain in modulating EGFR activation. Furthermore, we show that the oncogenic activity of the resulting C-terminal deletion mutants are efficiently inhibited by EGFR-targeted drugs including erlotinib, afatinib, dacomitinib as well as cetuximab, expanding the therapeutic rationale of cancer genome-based EGFR targeted approaches. Finally, in vivo and in vitro preclinical studies demonstrate that constitutive asymmetric dimerization in mutant EGFR is a key mechanism for oncogenic activation and tumorigenesis by C-terminal deletion mutants. Therefore, our data provide compelling evidence for oncogenic activation of C-terminal deletion mutants at the molecular level and we propose that C-terminal deletion status of EGFR can be considered as a potential genomic marker for EGFR-targeted therapy. PMID:25826094

  4. Molecular basis for multimerization in the activation of the epidermal growth factor receptor

    PubMed Central

    Huang, Yongjian; Bharill, Shashank; Karandur, Deepti; Peterson, Sean M; Marita, Morgan; Shi, Xiaojun; Kaliszewski, Megan J; Smith, Adam W; Isacoff, Ehud Y; Kuriyan, John

    2016-01-01

    The epidermal growth factor receptor (EGFR) is activated by dimerization, but activation also generates higher-order multimers, whose nature and function are poorly understood. We have characterized ligand-induced dimerization and multimerization of EGFR using single-molecule analysis, and show that multimerization can be blocked by mutations in a specific region of Domain IV of the extracellular module. These mutations reduce autophosphorylation of the C-terminal tail of EGFR and attenuate phosphorylation of phosphatidyl inositol 3-kinase, which is recruited by EGFR. The catalytic activity of EGFR is switched on through allosteric activation of one kinase domain by another, and we show that if this is restricted to dimers, then sites in the tail that are proximal to the kinase domain are phosphorylated in only one subunit. We propose a structural model for EGFR multimerization through self-association of ligand-bound dimers, in which the majority of kinase domains are activated cooperatively, thereby boosting tail phosphorylation. DOI: http://dx.doi.org/10.7554/eLife.14107.001 PMID:27017828

  5. Loss of p53 induces epidermal growth factor receptor promoter activity in normal human keratinocytes

    PubMed Central

    Bheda, A; Creek, KE; Pirisi, L

    2008-01-01

    Overexpression of the epidermal growth factor receptor (EGFR) in human papillomavirus type 16-immortalized human keratinocytes (HKc) is caused by the viral oncoprotein E6, which targets p53 for degradation. We have previously observed that expression of p53 RNAi in normal HKc is associated with an increase in EGFR mRNA and protein. We now report that p53 RNAi induces EGFR promoter activity up to approximately 10-fold in normal HKc, and this effect does not require intact p53 binding sites on the EGFR promoter. Exogenous wild-type p53 inhibits the EGFR promoter at low levels, and activates it at higher concentrations. Yin Yang 1 (YY1), which negatively regulates p53, induces EGFR promoter activity, and this effect is augmented by p53 RNAi. Intact p53 binding sites on the EGFR promoter are not required for activation by YY1. In addition, Sp1 and YY1 synergistically induce the EGFR promoter in normal HKc, indicating that Sp1 may recruit YY1 as a co-activator. Wild-type p53 suppressed Sp1- and YY1-mediated induction of the EGFR promoter. We conclude that acute loss of p53 in normal HKc induces EGFR expression bya mechanism that involves YY1 and Sp1 and does not require p53 binding to the EGFR promoter. PMID:18391986

  6. Activity-dependent release of transforming growth factor-beta in a neuronal network in vitro.

    PubMed

    Lacmann, A; Hess, D; Gohla, G; Roussa, E; Krieglstein, K

    2007-12-12

    For neurotrophins and also for members of the transforming growth factor beta (TGF-beta) family an activity-dependent regulation of synthesis and release has been proposed. Together with the observation that the secretion of neurotransmitters is initiated by neurotrophic factors, it is reasonable to assume that they might act as retrograde modulators enhancing the efficacy and stabilization of synapses. In the present study, we have tested this hypothesis and studied the release and regulation of TGF-beta in vitro using mouse primary hippocampal neurons at embryonic day E16.5 as model. We show that neuronal activity regulates TGF-beta release and TGF-beta expression in vitro. Treatment of the cultures with KCl, 3-veratroylveracevine (veratridine), glutamate or carbamylcholine chloride (carbachol) increased the levels of secreted TGF-beta, as assessed by the MLEC/plasminogen activator inhibitor (PAI)-luciferase-assay, whereas TGF-beta release stimulated by KCl or veratridine was reduced in the presence of tetrodotoxin or 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). In addition, application of glutamate significantly upregulated expression of TGF-beta2 and TGF-beta3 in the culture. Notably, KCl stimulation caused Smad (composite term from SMA (C. elegans) and MAD=mothers against dpp (Drosophila)) translocation into the nucleus and upregulated TGF-beta inducible early gene (Tieg1) expression, demonstrating that activity-dependent released TGF-beta may exert autocrine actions and thereby activate the TGF-beta-dependent signaling pathway. Together, these results suggest an activity-dependent release and gene transcription of TGF-beta from mouse hippocampal neurons in vitro as well as subsequent autocrine functions of the released TGF-beta within the hippocampal network.

  7. Transcriptional activation of the human epidermal growth factor receptor promoter by human p53.

    PubMed Central

    Ludes-Meyers, J H; Subler, M A; Shivakumar, C V; Munoz, R M; Jiang, P; Bigger, J E; Brown, D R; Deb, S P; Deb, S

    1996-01-01

    The human epidermal growth factor receptor (EGFR) promoter is activated by both wild-type and tumor-derived mutant p53. In this communication, we demonstrate that EGFR promoter sequence requirements for transactivation by wild-type and mutant p53 are different. Transient-expression assays with EGFR promoter deletions identified a wild-type human p53 response element, 5'-AGCTAGACGTCCGGGCAGCCCCCGGCG -3', from positions --265 to --239. Electrophoretic mobility shift analysis and DNase I footprinting assays indicated that wild-type p53 binds sequence specifically to the response element. Using circularly permuted DNA fragments containing the p53-binding site, we show that wild-type p53 binding induces DNA bending at this site. We further show that the EGFR promoter is also activated by tumor-derived p53 mutants p53-143A, p53-175H, p53-248W, p53-273H, and p53-281G. However, the transactivation by mutant p53 does not require the wild-type p53-binding site. The minimal EGFR promoter from positions --104 to --20 which does not contain the wild-type p53-binding site is transactivated by the p53 mutants but not by the wild-type protein, showing a difference in the mechanism of transactivation by wild-type and mutant p53. Transactivation of the EGFR promoter by p53 may represent a novel mechanism of cell growth regulation. PMID:8887630

  8. The hypoxia-inducible factor-1α activates ectopic production of fibroblast growth factor 23 in tumor-induced osteomalacia

    PubMed Central

    Zhang, Qian; Doucet, Michele; Tomlinson, Ryan E; Han, Xiaobin; Quarles, L Darryl; Collins, Michael T; Clemens, Thomas L

    2016-01-01

    Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome in which ectopic production of fibroblast growth factor 23 (FGF23) by non-malignant mesenchymal tumors causes phosphate wasting and bone fractures. Recent studies have implicated the hypoxia-inducible factor-1α (HIF-1α) in other phosphate wasting disorders caused by elevated FGF23, including X-linked hypophosphatemic rickets and autosomal dominant hypophosphatemia. Here we provide evidence that HIF-1α mediates aberrant FGF23 in TIO by transcriptionally activating its promoter. Immunohistochemical studies in phosphaturic mesenchymal tumors resected from patients with documented TIO showed that HIF-1α and FGF23 were co-localized in spindle-shaped cells adjacent to blood vessels. Cultured tumor tissue produced high levels of intact FGF23 and demonstrated increased expression of HIF-1α protein. Transfection of MC3T3-E1 and Saos-2 cells with a HIF-1α expression construct induced the activity of a FGF23 reporter construct. Prior treatment of tumor organ cultures with HIF-1α inhibitors decreased HIF-1α and FGF23 protein accumulation and inhibited HIF-1α-induced luciferase reporter activity in transfected cells. Chromatin immunoprecipitation assays confirmed binding to a HIF-1α consensus sequence within the proximal FGF23 promoter, which was eliminated by treatment with a HIF-1α inhibitor. These results show for the first time that HIF-1α is a direct transcriptional activator of FGF23 and suggest that upregulation of HIF-1α activity in TIO contributes to the aberrant FGF23 production in these patients. PMID:27468359

  9. Overexpressed homeobox B9 regulates oncogenic activities by transforming growth factor-β1 in gliomas

    SciTech Connect

    Fang, Liping; Xu, Yinghui; Zou, Lijuan

    2014-03-28

    Highlights: • HOXB9 is overexpressed in gliomas. • HOXB9 over expression had shorter survival time than down expression in gliomas. • HOXB9 stimulated the proliferation, migration and sphere formation of glioma cells. • Activation of TGF-β1 contributed to HOXB9-induced oncogenic activities. - Abstract: Glioma is the leading cause of deaths related to tumors in the central nervous system. The mechanisms of gliomagenesis remain elusive to date. Homeobox B9 (HOXB9) has a crucial function in the regulation of gene expression and cell survival, but its functions in glioma formation and development have yet to be elucidated. This study showed that HOXB9 expression in glioma tissues was significantly higher than that in nontumor tissues. Higher HOXB9 expression was also significantly associated with advanced clinical stage in glioma patients. HOXB9 overexpression stimulated the proliferation, migration, and sphere formation of glioma cells, whereas HOXB9 knockdown elicited an opposite effect. HOXB9 overexpression also increased the tumorigenicity of glioma cells in vivo. Moreover, the activation of transforming growth factor-β1 contributed to HOXB9-induced oncogenic activities. HOXB9 could be used as a predictable biomarker to be detected in different pathological and histological subtypes in glioma for diagnosis or prognosis.

  10. A living thick nanofibrous implant bifunctionalized with active growth factor and stem cells for bone regeneration.

    PubMed

    Eap, Sandy; Keller, Laetitia; Schiavi, Jessica; Huck, Olivier; Jacomine, Leandro; Fioretti, Florence; Gauthier, Christian; Sebastian, Victor; Schwinté, Pascale; Benkirane-Jessel, Nadia

    2015-01-01

    New-generation implants focus on robust, durable, and rapid tissue regeneration to shorten recovery times and decrease risks of postoperative complications for patients. Herein, we describe a new-generation thick nanofibrous implant functionalized with active containers of growth factors and stem cells for regenerative nanomedicine. A thick electrospun poly(ε-caprolactone) nanofibrous implant (from 700 μm to 1 cm thick) was functionalized with chitosan and bone morphogenetic protein BMP-7 as growth factor using layer-by-layer technology, producing fish scale-like chitosan/BMP-7 nanoreservoirs. This extracellular matrix-mimicking scaffold enabled in vitro colonization and bone regeneration by human primary osteoblasts, as shown by expression of osteocalcin, osteopontin, and bone sialoprotein (BSPII), 21 days after seeding. In vivo implantation in mouse calvaria defects showed significantly more newly mineralized extracellular matrix in the functionalized implant compared to a bare scaffold after 30 days' implantation, as shown by histological scanning electron microscopy/energy dispersive X-ray microscopy study and calcein injection. We have as well bifunctionalized our BMP-7 therapeutic implant by adding human mesenchymal stem cells (hMSCs). The activity of this BMP-7-functionalized implant was again further enhanced by the addition of hMSCs to the implant (living materials), in vivo, as demonstrated by the analysis of new bone formation and calcification after 30 days' implantation in mice with calvaria defects. Therefore, implants functionalized with BMP-7 nanocontainers associated with hMSCs can act as an accelerator of in vivo bone mineralization and regeneration. PMID:25709432

  11. Cloning, Expression, and Cost Effective Purification of Authentic Human Epidermal Growth Factor With High Activity

    PubMed Central

    Pouranvari, Sara; Ebrahimi, Firouz; Javadi, Gholamreza; Maddah, Bozorgmehr

    2016-01-01

    Background: Epidermal growth factor (EGF) plays a fundamental role in the healing of wounds relating to skin damage, the cornea, and the gastrointestinal tract. Objectives: The aim of this study is the cloning, expression, and purification of recombinant human EGF (rhEGF), and an assessment of its activity. Materials and Methods: In the present experimental study, a synthetic pET28a (+) -hEGF construct was prepared. In order to ligate hEGF into pET24a (+), the PCR technique was performed, using special primers that possess restriction enzyme sites, which are also located in appropriate sites in pET24a (+). After transferring this construct into E. coli cells, protein expression was performed under standard conditions. Protein solubilization was done by urea. hEGF purification and refolding were carried out using gradient dialysis against the urea. We used RP-HPLC to compare between rhEGF and commercial rhEGF as a control. Finally, an MTT assay was performed to assess the viability of the NIH 3T3 cells treated with various concentrations of rhEGF. Results: Dialysis after urea solubilization caused precipitation of unwanted proteins, resulting in achievement of purified EGF with > 90% purity, without the need for expensive and time-consuming process. The MTT assay results showed that our rhEGF activate significantly higher proliferation of NIH 3T3 cells in comparison to the control (P-values were < 0.0001), in total concentrations and times evaluated Conclusions: Via our purification protocol, a sufficient amount of bioactive recombinant human epidermal growth factor was obtained in just a few affordable steps, with superlative purity. PMID:27247796

  12. A living thick nanofibrous implant bifunctionalized with active growth factor and stem cells for bone regeneration

    PubMed Central

    Eap, Sandy; Keller, Laetitia; Schiavi, Jessica; Huck, Olivier; Jacomine, Leandro; Fioretti, Florence; Gauthier, Christian; Sebastian, Victor; Schwinté, Pascale; Benkirane-Jessel, Nadia

    2015-01-01

    New-generation implants focus on robust, durable, and rapid tissue regeneration to shorten recovery times and decrease risks of postoperative complications for patients. Herein, we describe a new-generation thick nanofibrous implant functionalized with active containers of growth factors and stem cells for regenerative nanomedicine. A thick electrospun poly(ε-caprolactone) nanofibrous implant (from 700 μm to 1 cm thick) was functionalized with chitosan and bone morphogenetic protein BMP-7 as growth factor using layer-by-layer technology, producing fish scale-like chitosan/BMP-7 nanoreservoirs. This extracellular matrix-mimicking scaffold enabled in vitro colonization and bone regeneration by human primary osteoblasts, as shown by expression of osteocalcin, osteopontin, and bone sialoprotein (BSPII), 21 days after seeding. In vivo implantation in mouse calvaria defects showed significantly more newly mineralized extracellular matrix in the functionalized implant compared to a bare scaffold after 30 days’ implantation, as shown by histological scanning electron microscopy/energy dispersive X-ray microscopy study and calcein injection. We have as well bifunctionalized our BMP-7 therapeutic implant by adding human mesenchymal stem cells (hMSCs). The activity of this BMP-7-functionalized implant was again further enhanced by the addition of hMSCs to the implant (living materials), in vivo, as demonstrated by the analysis of new bone formation and calcification after 30 days’ implantation in mice with calvaria defects. Therefore, implants functionalized with BMP-7 nanocontainers associated with hMSCs can act as an accelerator of in vivo bone mineralization and regeneration. PMID:25709432

  13. AP-2{alpha} suppresses skeletal myoblast proliferation and represses fibroblast growth factor receptor 1 promoter activity

    SciTech Connect

    Mitchell, Darrion L.; DiMario, Joseph X.

    2010-01-15

    Skeletal muscle development is partly characterized by myoblast proliferation and subsequent differentiation into postmitotic muscle fibers. Developmental regulation of expression of the fibroblast growth factor receptor 1 (FGFR1) gene is required for normal myoblast proliferation and muscle formation. As a result, FGFR1 promoter activity is controlled by multiple transcriptional regulatory proteins during both proliferation and differentiation of myogenic cells. The transcription factor AP-2{alpha} is present in nuclei of skeletal muscle cells and suppresses myoblast proliferation in vitro. Since FGFR1 gene expression is tightly linked to myoblast proliferation versus differentiation, the FGFR1 promoter was examined for candidate AP-2{alpha} binding sites. Mutagenesis studies indicated that a candidate binding site located at - 1035 bp functioned as a repressor cis-regulatory element. Furthermore, mutation of this site alleviated AP-2{alpha}-mediated repression of FGFR1 promoter activity. Chromatin immunoprecipitation studies demonstrated that AP-2{alpha} interacted with the FGFR1 promoter in both proliferating myoblasts and differentiated myotubes. In total, these results indicate that AP-2{alpha} is a transcriptional repressor of FGFR1 gene expression during skeletal myogenesis.

  14. Multimodular biosensors reveal a novel platform for activation of G proteins by growth factor receptors

    PubMed Central

    Midde, Krishna K.; Aznar, Nicolas; Laederich, Melanie B.; Ma, Gary S.; Kunkel, Maya T.; Newton, Alexandra C.; Ghosh, Pradipta

    2015-01-01

    Environmental cues are transmitted to the interior of the cell via a complex network of signaling hubs. Receptor tyrosine kinases (RTKs) and trimeric G proteins are two such major signaling hubs in eukaryotes. Conventionally, canonical signal transduction via trimeric G proteins is thought to be triggered exclusively by G protein-coupled receptors. Here we used molecular engineering to develop modular fluorescent biosensors that exploit the remarkable specificity of bimolecular recognition, i.e., of both G proteins and RTKs, and reveal the workings of a novel platform for activation of G proteins by RTKs in single living cells. Comprised of the unique modular makeup of guanidine exchange factor Gα-interacting vesicle-associated protein (GIV)/girdin, a guanidine exchange factor that links G proteins to a variety of RTKs, these biosensors provide direct evidence that RTK–GIV–Gαi ternary complexes are formed in living cells and that Gαi is transactivated within minutes after growth factor stimulation at the plasma membrane. Thus, GIV-derived biosensors provide a versatile strategy for visualizing, monitoring, and manipulating the dynamic association of Gαi with RTKs for noncanonical transactivation of G proteins in cells and illuminate a fundamental signaling event regulated by GIV during diverse cellular processes and pathophysiologic states. PMID:25713130

  15. Multimodular biosensors reveal a novel platform for activation of G proteins by growth factor receptors.

    PubMed

    Midde, Krishna K; Aznar, Nicolas; Laederich, Melanie B; Ma, Gary S; Kunkel, Maya T; Newton, Alexandra C; Ghosh, Pradipta

    2015-03-01

    Environmental cues are transmitted to the interior of the cell via a complex network of signaling hubs. Receptor tyrosine kinases (RTKs) and trimeric G proteins are two such major signaling hubs in eukaryotes. Conventionally, canonical signal transduction via trimeric G proteins is thought to be triggered exclusively by G protein-coupled receptors. Here we used molecular engineering to develop modular fluorescent biosensors that exploit the remarkable specificity of bimolecular recognition, i.e., of both G proteins and RTKs, and reveal the workings of a novel platform for activation of G proteins by RTKs in single living cells. Comprised of the unique modular makeup of guanidine exchange factor Gα-interacting vesicle-associated protein (GIV)/girdin, a guanidine exchange factor that links G proteins to a variety of RTKs, these biosensors provide direct evidence that RTK-GIV-Gαi ternary complexes are formed in living cells and that Gαi is transactivated within minutes after growth factor stimulation at the plasma membrane. Thus, GIV-derived biosensors provide a versatile strategy for visualizing, monitoring, and manipulating the dynamic association of Gαi with RTKs for noncanonical transactivation of G proteins in cells and illuminate a fundamental signaling event regulated by GIV during diverse cellular processes and pathophysiologic states.

  16. Retrograde fibroblast growth factor 22 (FGF22) signaling regulates insulin-like growth factor 2 (IGF2) expression for activity-dependent synapse stabilization in the mammalian brain

    PubMed Central

    Terauchi, Akiko; Johnson-Venkatesh, Erin M; Bullock, Brenna; Lehtinen, Maria K; Umemori, Hisashi

    2016-01-01

    Communication between pre- and postsynaptic cells promotes the initial organization of synaptic specializations, but subsequent synaptic stabilization requires transcriptional regulation. Here we show that fibroblast growth factor 22 (FGF22), a target-derived presynaptic organizer in the mouse hippocampus, induces the expression of insulin-like growth factor 2 (IGF2) for the stabilization of presynaptic terminals. FGF22 is released from CA3 pyramidal neurons and organizes the differentiation of excitatory nerve terminals formed onto them. Local application of FGF22 on the axons of dentate granule cells (DGCs), which are presynaptic to CA3 pyramidal neurons, induces IGF2 in the DGCs. IGF2, in turn, localizes to DGC presynaptic terminals and stabilizes them in an activity-dependent manner. IGF2 application rescues presynaptic defects of Fgf22-/- cultures. IGF2 is dispensable for the initial presynaptic differentiation, but is required for the following presynaptic stabilization both in vitro and in vivo. These results reveal a novel feedback signal that is critical for the activity-dependent stabilization of presynaptic terminals in the mammalian hippocampus. DOI: http://dx.doi.org/10.7554/eLife.12151.001 PMID:27083047

  17. Direct Demonstration of Separate Receptors for Growth and Metabolic Activities of Insulin and Multiplication-stimulating Activity (an Insulinlike Growth Factor) Using Antibodies to the Insulin Receptor

    PubMed Central

    King, George L.; Kahn, C. Ronald; Rechler, Matthew M.; Nissley, S. Peter

    1980-01-01

    Insulin and such insulinlike growth factors as multiplication stimulating activity (MSA) are related polypeptides that have common biological activities. Both insulin and MSA produce acute metabolic responses (stimulation of glucose oxidation in isolated fat cells) as well as growth effects (stimulation of [3H]thymidine incorporation into DNA in cultured fibroblasts). In addition, most cells have separate receptors for insulin and insulinlike growth factors, and both peptides have weaker affinity for each other's specific receptors than for their own. To determine, therefore, whether these effects are mediated by receptors for insulin, insulinlike growth factors, or both, we have selectively blocked insulin receptors with a specific antagonist, namely Fab fragments derived from naturally occurring antibodies to the insulin receptor. In rat adipocytes, 10 μg/ml of antireceptor Fab inhibited insulin binding by 90%, whereas it inhibited MSA binding <5%. The anti-insulin receptor Fab is without intrinsic biological activity, but acts as a competitive inhibitor of insulin receptors. Blockade of insulin receptors with Fab fragments produced a 30-fold rightward shift in the dose response for stimulation of glucose oxidation by both insulin and MSA. The dose-response curves for stimulation of oxidation by vitamin K5 and spermine, agents that stimulate glucose oxidation through noninsulin receptor pathways, were not affected by the blockade of insulin receptors with Fab antibody fragments. These data suggest that this acute metabolic effect of both insulin and MSA is mediated via the insulin receptor. In cultured human fibroblasts, 10 μg/ml of Fab inhibited insulin binding by 90% and MSA binding by 15%. In fibroblasts, however, blockade of the insulin receptor did not alter the dose response for stimulation of thymidine incorporation into DNA by either insulin or MSA. Furthermore, intact antireceptor antibody immunoglobulin (Ig)G, which produces multiple other insulinlike

  18. Inhibition of fatty acid oxidation activates transforming growth factor-beta in cerebrospinal fluid and decreases spontaneous motor activity.

    PubMed

    Fujikawa, Teppei; Fujita, Ryo; Iwaki, Yoko; Matsumura, Shigenobu; Fushiki, Tohru; Inoue, Kazuo

    2010-10-01

    We have previously reported that transforming growth factor (TGF)-beta in the cerebrospinal fluid (CSF) is involved in the mechanism underlying the regulation of spontaneous motor activity (SMA) by the central nervous system after exercise. However, it remained unclear what physiological condition triggers the activation of TGF-beta. We hypothesized that the shortage of energy derived from fatty acid (FA) oxidation observed in the early phase of exercise activated TGF-beta in the CSF. To test this hypothesis, we investigated whether mercaptoacetate (MA), an inhibitor of FA oxidation, could induce an activation of TGF-beta in the CSF and a decrease in SMA. Intraperitoneal (i.p.) administration of MA activated TGF-beta in CSF in rats and depressed SMA; 2-deoxyglucose, an inhibitor of carbohydrate oxidation, on the other hand, depressed SMA but failed to activate CSF TGF-beta. Intracisternal administration of anti-TGF-beta antibody abolished the depressive effect of MA on SMA. We also found that the depression of SMA and the activation of TGF-beta in the CSF by i.p. MA administration were eliminated by vagotomy. Our data suggest that TGF-beta in the CSF is activated by the inhibition of FA oxidation via the vagus nerve and that this subsequently induces depression of SMA.

  19. Graphene Enhances Cellular Proliferation through Activating the Epidermal Growth Factor Receptor.

    PubMed

    Liu, Wei; Sun, Cheng; Liao, Chunyang; Cui, Lin; Li, Haishan; Qu, Guangbo; Yu, Wenlian; Song, Naining; Cui, Yuan; Wang, Zheng; Xie, Wenping; Chen, Huiming; Zhou, Qunfang

    2016-07-27

    Graphene has promising applications in food packaging, water purification, and detective sensors for contamination monitoring. However, the biological effects of graphene are not fully understood. It is necessary to clarify the potential risks of graphene exposure to humans through diverse routes, such as foods. In the present study, graphene, as the model nanomaterial, was used to test its potential effects on the cell proliferation based on multiple representative cell lines, including HepG2, A549, MCF-7, and HeLa cells. Graphene was characterized by Raman spectroscopy, particle size analysis, atomic force microscopy, and transmission electron microscopy. The cellular responses to graphene exposure were evaluated using flow cytometry, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and alamarBlue assays. Rat cerebral astrocyte cultures, as the non-cancer cells, were used to assess the potential cytotoxicity of graphene as well. The results showed that graphene stimulation enhanced cell proliferation in all tested cell cultures and the highest elevation in cell growth was up to 60%. A western blot assay showed that the expression of epidermal growth factor (EGF) was upregulated upon graphene treatment. The phosphorylation of EGF receptor (EGFR) and the downstream proteins, ShC and extracellular regulating kinase (ERK), were remarkably induced, indicating that the activation of the mitogen-activated protein kinase (MAPK)/ERK signaling pathway was triggered. The activation of PI3 kinase p85 and AKT showed that the PI3K/AKT signaling pathway was also involved in graphene-induced cell proliferation, causing the increase of cell ratios in the G2/M phase. No influences on cell apoptosis were observed in graphene-treated cells when compared to the negative controls, proving the low cytotoxicity of this emerging nanomaterial. The findings in this study revealed the potential cellular biological effect of graphene, which may give useful hints on its biosafety

  20. Leukemia inhibitory factor promotes tumor growth and metastasis in human osteosarcoma via activating STAT3.

    PubMed

    Liu, Bin; Lu, Yi; Li, Jinzhi; Liu, Yanping; Liu, Jian; Wang, Weiguo

    2015-10-01

    The leukemia inhibitory factor (LIF) has been demonstrated to be an oncogene and participated in multiple procedures during the initiation and progression of many human malignancies. However, the role of LIF in osteosarcoma is still largely unknown. Here, we performed a series of in vitro and in vivo experiments to investigate the expression and biological functions of LIF in osteosarcoma. Compared to that in the non-cancerous tissues, LIF was significantly overexpressed in a panel of 68 osteosarcoma samples (p < 0.0001). Moreover, the overexpression of LIF was significantly correlated with advanced tumor stage, larger tumor size, and shorter overall survival. In addition, knockdown of LIF notably suppressed the proliferation and invasion of osteosarcoma via blocking the STAT3 signal pathway; in contrast, treatment with the recombinant LIF protein significantly promoted the growth and invasion of osteosarcoma through enhancing the phosphorylation of STAT3, which can be partially neutralized by the STAT3 inhibitor, HO-3867. In conclusion, we demonstrated that LIF was frequently overexpressed in osteosarcoma, which could promote the growth and invasion through activating the STAT3 pathway. Our findings proposed that LIF might be a potent therapeutic target for osteosarcoma.

  1. Leukemia inhibitory factor promotes tumor growth and metastasis in human osteosarcoma via activating STAT3.

    PubMed

    Liu, Bin; Lu, Yi; Li, Jinzhi; Liu, Yanping; Liu, Jian; Wang, Weiguo

    2015-10-01

    The leukemia inhibitory factor (LIF) has been demonstrated to be an oncogene and participated in multiple procedures during the initiation and progression of many human malignancies. However, the role of LIF in osteosarcoma is still largely unknown. Here, we performed a series of in vitro and in vivo experiments to investigate the expression and biological functions of LIF in osteosarcoma. Compared to that in the non-cancerous tissues, LIF was significantly overexpressed in a panel of 68 osteosarcoma samples (p < 0.0001). Moreover, the overexpression of LIF was significantly correlated with advanced tumor stage, larger tumor size, and shorter overall survival. In addition, knockdown of LIF notably suppressed the proliferation and invasion of osteosarcoma via blocking the STAT3 signal pathway; in contrast, treatment with the recombinant LIF protein significantly promoted the growth and invasion of osteosarcoma through enhancing the phosphorylation of STAT3, which can be partially neutralized by the STAT3 inhibitor, HO-3867. In conclusion, we demonstrated that LIF was frequently overexpressed in osteosarcoma, which could promote the growth and invasion through activating the STAT3 pathway. Our findings proposed that LIF might be a potent therapeutic target for osteosarcoma. PMID:26271643

  2. Cyclic mechanical deformation stimulates human lung fibroblast proliferation and autocrine growth factor activity.

    PubMed

    Bishop, J E; Mitchell, J J; Absher, P M; Baldor, L; Geller, H A; Woodcock-Mitchell, J; Hamblin, M J; Vacek, P; Low, R B

    1993-08-01

    Cellular hypertrophy and hyperplasia and increased extracellular matrix deposition are features of tissue hypertrophy resulting from increased work load. It is known, for example, that mechanical forces play a critical role in lung development, cardiovascular remodeling following pressure overload, and skeletal muscle growth. The mechanisms involved in these processes, however, remain unclear. Here we examined the effect of mechanical deformation on fibroblast function in vitro. IMR-90 human fetal lung fibroblasts grown on collagen-coated silastic membranes were subjected to cyclical mechanical deformation (10% increase in culture surface area; 1 Hz) for up to 5 days. Cell number was increased by 39% after 2 days of deformation (1.43 +/- .01 x 10(5) cells/membrane compared with control, 1.03 +/- 0.02 x 10(5) cells; mean +/- SEM; P < 0.02) increasing to 163% above control by 4 days (2.16 +/- 0.16 x 10(5) cells compared with 0.82 +/- 0.03 x 10(5) cells; P < 0.001). The medium from mechanically deformed cells was mitogenic for IMR-90 cells, with maximal activity in the medium from cells mechanically deformed for 2 days (stimulating cell replication by 35% compared with media control; P < 0.002). These data suggest that mechanical deformation stimulates human lung fibroblast replication and that this effect is mediated by the release of autocrine growth factors.

  3. Molecular Basis for Redox Activation of Epidermal Growth Factor Receptor Kinase.

    PubMed

    Truong, Thu H; Ung, Peter Man-Un; Palde, Prakash B; Paulsen, Candice E; Schlessinger, Avner; Carroll, Kate S

    2016-07-21

    Epidermal growth factor receptor (EGFR) is a target of signal-derived H2O2, and oxidation of active-site cysteine 797 to sulfenic acid enhances kinase activity. Although a major class of covalent drugs targets C797, nothing is known about its catalytic importance or how S-sulfenylation leads to activation. Here, we report the first detailed functional analysis of C797. In contrast to prior assumptions, mutation of C797 diminishes catalytic efficiency in vitro and cells. The experimentally determined pKa and reactivity of C797 toward H2O2 correspondingly distinguish this residue from the bulk of the cysteinome. Molecular dynamics simulation of reduced versus oxidized EGFR, reinforced by experimental testing, indicates that sulfenylation of C797 allows new electrostatic interactions to be formed with the catalytic loop. Finally, we show that chronic oxidative stress yields an EGFR subpopulation that is refractory to the FDA-approved drug afatinib. Collectively, our data highlight the significance of redox biology to understanding kinase regulation and drug pharmacology. PMID:27427230

  4. Connective tissue growth factor production by activated pancreatic stellate cells in mouse alcoholic chronic pancreatitis

    PubMed Central

    Charrier, Alyssa; Brigstock, David R.

    2010-01-01

    Alcoholic chronic pancreatitis (ACP) is characterized by pancreatic necrosis, inflammation, and scarring, the latter of which is due to excessive collagen deposition by activated pancreatic stellate cells (PSC). The aim of this study was to establish a model of ACP in mice, a species that is usually resistant to the toxic effects of alcohol, and to identify the cell type(s) responsible for production of connective tissue growth factor (CTGF), a pro-fibrotic molecule. C57Bl/6 male mice received intraperitoneal ethanol injections for three weeks against a background of cerulein-induced acute pancreatitis. Peak blood alcohol levels remained consistently high in ethanol-treated mice as compared to control mice. In mice receiving ethanol plus cerulein, there was increased collagen deposition as compared to other treatment groups as well as increased frequency of α-smooth muscle actin and desmin-positive PSC which also demonstrated significantly enhanced CTGF protein production. Expression of mRNA for collagen α1(I), α-smooth muscle actin or CTGF were all increased and co-localized exclusively to activated PSC in ACP. Pancreatic expression of mRNA for key profibrotic markers were all increased in ACP. In conclusion, a mouse model of ACP has been developed that mimics key pathophysiological features of the disease in humans and which shows that activated PSC are the principal producers of collagen and CTGF. PSC-derived CTGF is thus a candidate therapeutic target in anti-fibrotic strategies for ACP. PMID:20368699

  5. Silk fibroin sponges with cell growth-promoting activity induced by genetically fused basic fibroblast growth factor.

    PubMed

    Kambe, Yusuke; Kojima, Katsura; Tamada, Yasushi; Tomita, Naohide; Kameda, Tsunenori

    2016-01-01

    Transgenic silkworm technology has enabled the biological properties of silk fibroin protein to be altered by fusion to recombinant bioactive proteins. However, few studies have reported the fabrication of genetically modified fibroin proteins into three-dimensional spongy structures to serve as scaffolds for tissue engineering. We generated a transgenic silkworm strain that produces fibroin fused to basic fibroblast growth factor (bFGF) and processed the fibroin into a spongy structure using a simple freeze/thaw method. NIH3T3 mouse embryonic fibroblasts grown on bFGF-fused fibroin sponges proliferated and spread out well, showing half the population doubling time of cells cultured on wild-type fibroin sponges. Furthermore, the number of primary rabbit articular chondrocytes growing on bFGF-fused fibroin sponges was around five-times higher than that of the wild-type control at 3-days post cell-seeding. As the physical properties of wild-type and bFGF-fused fibroin sponges were almost identical, it is suggested that bFGF fused to fibroin retained its biological activity, even after the bFGF-fused fibroin was fabricated into the spongy structure. The bFGF-fused fibroin sponge has the potential for widespread application in the field of tissue engineering, and the method of fabricating this structure could be applicable to other recombinant bioactive fibroin proteins.

  6. Amyloid beta-peptide possesses a transforming growth factor-beta activity.

    PubMed

    Huang, S S; Huang, F W; Xu, J; Chen, S; Hsu, C Y; Huang, J S

    1998-10-16

    Amyloid beta-peptide (Abeta) of 39-42 amino acid residues is a major constituent of Alzheimer's disease neurite plaques. Abeta aggregates (fibrils) are believed to be responsible for neuronal damage and dysfunction, as well as microglia and astrocyte activation in disease lesions by multiple mechanisms. Since Abeta aggregates possess the multiple valencies of an FAED motif (20th to 23rd amino acid residues), which resembles the putative transforming growth factor-beta (TGF-beta) active site motif, we hypothesize that Abeta monomers and Abeta aggregates may function as TGF-beta antagonists and partial agonists, analogous to previously described monovalent and multivalent TGF-beta peptide antagonists and agonists (Huang, S. S., Liu, Q., Johnson, F. E., Konish, Y., and Huang, J. S. (1997) J. Biol. Chem. 272, 27155-27159). Here, we report that the Abeta monomer, Abeta-(1-40) and its fragment, containing the motif inhibit radiolabeled TGF-beta binding to cell-surface TGF-beta receptors in mink lung epithelial cells (Mv1Lu cells). Abeta-(1-40)-bovine serum albumin conjugate (Abeta-(1-40)-BSA), a multivalent synthetic analogue of Abeta aggregates, exhibited cytotoxicity toward bovine cerebral endothelial cells and rat post-mitotic differentiated hippocampal neuronal cells (H19-7 cells) and inhibitory activities of radiolabeled TGF-beta binding to TGF-beta receptors and TGF-beta-induced plasminogen activator inhibitor-1 expression, that were approximately 100-670 times more potent than those of Abeta-(1-40) monomers. At less than micromolar concentrations, Abeta-(1-40)-BSA but not Abeta-(1-40) monomers inhibited proliferation of Mv1Lu cells. Since TGF-beta is an organizer of responses to neurodegeneration and is also found in neurite plaques, the TGF-beta antagonist and partial agonist activities of Abeta monomers and aggregates may play an important role in the pathogenesis of the disease.

  7. Tailored delivery of active keratinocyte growth factor from biodegradable polymer formulations.

    PubMed

    Cho, Eun Jeong; Tao, Zunyu; Tang, Ying; Tehan, Elizabeth C; Bright, Frank V; Hicks, Wesley L; Gardella, Joseph A; Hard, Robert

    2003-08-01

    We report the results of a high throughput screening campaign that is aimed to develop a biodegradable polymer-based formulation to deliver active keratinocyte growth factor (KGF) and provide a means to tune the KGF delivery rate. A statistical design strategy was used to prepare and screen a series of polymer blends that were composed of poly(lactic acid) (PLA), poly(glycolic acid) (PGA), and the surfactant sodium bis(ethylhexyl)sulfosuccinate (Aerosol-OT, AOT). Chloroform was the solvent. Our high throughput screening method used a two-tiered assessment strategy. At Level 1, we identified "lead" KFG-loaded formulations that exhibited KGF emission spectra that were the most similar to the native KGF spectrum recorded in buffer. At Level 2, we used steady-state emission and a homogeneous polarization immunoassay strategy to determine the concentration of total and active KGF, respectively, liberated from the lead formulations during biodegradation. After preparing and screening 2500 formulations, we identified several viable, lead formulations. An analysis of the data showed that the combination of PLA, PGA, and AOT were important to yield a high fraction of active KGF upon release from the formulation; no combination of any two together produced an effect as good as the ternary formulation. The optimum formulations that yielded the highest fraction of active KGF upon release had the following general features: PLA/PGA (w/w) near unity, AOT loading of 100-200 mM, water/AOT mole ratio of 10-20, and a pH between 6 and 8. PLA alone cast from chloroform delivered KGF, but that KGF did not bind to anti-KGF antibodies (i.e., it was inactive). We can tune the KGF release kinetics by more than two orders of magnitude while maintaining the KGF activity upon liberation from the formulation by adjusting the PLA molecular weight.

  8. Recurrent exposure to nicotine differentiates human bronchial epithelial cells via epidermal growth factor receptor activation

    SciTech Connect

    Martinez-Garcia, Eva; Irigoyen, Marta; Anso, Elena; Martinez-Irujo, Juan Jose; Rouzaut, Ana

    2008-05-01

    Cigarette smoking is the major preventable cause of lung cancer in developed countries. Nicotine (3-(1-methyl-2-pyrrolidinyl)-pyridine) is one of the major alkaloids present in tobacco. Besides its addictive properties, its effects have been described in panoply of cell types. In fact, recent studies have shown that nicotine behaves as a tumor promoter in transformed epithelial cells. This research focuses on the effects of acute repetitive nicotine exposure on normal human bronchial epithelial cells (NHBE cells). Here we show that treatment of NHBE cells with recurrent doses of nicotine up to 500 {mu}M triggered cell differentiation towards a neuronal-like phenotype: cells emitted filopodia and expressed neuronal markers such as neuronal cell adhesion molecule, neurofilament-M and the transcription factors neuronal N and Pax-3. We also demonstrate that nicotine treatment induced NF-kB translocation to the nucleus, phosphorylation of the epidermal growth factor receptor (EGFR), and accumulation of heparin binding-EGF in the extracellular medium. Moreover, addition of AG1478, an inhibitor of EGFR tyrosine phosphorylation, or cetuximab, a monoclonal antibody that precludes ligand binding to the same receptor, prevented cell differentiation by nicotine. Lastly, we show that differentiated cells increased their adhesion to the extracellular matrix and their protease activity. Given that several lung pathologies are strongly related to tobacco consumption, these results may help to better understand the damaging consequences of nicotine exposure.

  9. The Growth Factor Receptor ERBB2 Regulates Mitochondrial Activity on a Signaling Time Scale*

    PubMed Central

    Patel, Nirav; Barrientos, Antoni; Landgraf, Ralf

    2013-01-01

    Overexpression of the ERBB2 receptor tyrosine kinase and the mitochondrial inner membrane protein UCP2 occurs frequently in aggressive cancers with dysfunctional mitochondria. Overexpressed ERBB2 signals constitutively and elevated UCP2 can uncouple mitochondria and alleviate oxidative stress. However, the physiological contributions of UCP2 and ERBB2 at the low expression levels that are typical of most tissues, as well as the path to oncogenic deregulation, are poorly understood. We now show that ERBB2 directly controls UCP2 levels, both at low physiological levels and oncogenic overexpression. At low levels of receptor and UCP2, ligand stimulation creates a distinct temporal response pattern driven by the opposing forces of translational suppression of the exceptionally short lived UCP2 protein and a time delayed transcriptional up-regulation. The latter becomes dominant through constitutive signaling by overexpressed ERBB2, resulting in high levels of UCP2 that contribute mitochondrial uncoupling. By contrast, ligand stimulation of non-overexpressed ERBB2 transiently removes UCP2 and paradoxically reduces the mitochondrial membrane potential, oxygen consumption, and OXPHOS on a signaling time scale. However, neither the transporter activity nor down-regulation of already low UCP2 levels drive this reduction in mitochondrial activity. Instead, UCP2 is required to establish mitochondria that are capable of responding to ligand. UCP2 knockdown impairs proliferation at high glucose but its absence specifically impairs ligand-induced growth when glucose levels fluctuate. These findings demonstrate the ability of growth factor signaling to control oxidative phosphorylation on a signaling time scale and point toward a non-transporter role for low levels of UCP2 in establishing dynamic response capability. PMID:24142693

  10. Membrane-to-nucleus signaling links insulin-like growth factor-1- and stem cell factor-activated pathways.

    PubMed

    Hayashi, Yujiro; Asuzu, David T; Gibbons, Simon J; Aarsvold, Kirsten H; Bardsley, Michael R; Lomberk, Gwen A; Mathison, Angela J; Kendrick, Michael L; Shen, K Robert; Taguchi, Takahiro; Gupta, Anu; Rubin, Brian P; Fletcher, Jonathan A; Farrugia, Gianrico; Urrutia, Raul A; Ordog, Tamas

    2013-01-01

    Stem cell factor (mouse: Kitl, human: KITLG) and insulin-like growth factor-1 (IGF1), acting via KIT and IGF1 receptor (IGF1R), respectively, are critical for the development and integrity of several tissues. Autocrine/paracrine KITLG-KIT and IGF1-IGF1R signaling are also activated in several cancers including gastrointestinal stromal tumors (GIST), the most common sarcoma. In murine gastric muscles, IGF1 promotes Kitl-dependent development of interstitial cells of Cajal (ICC), the non-neoplastic counterpart of GIST, suggesting cooperation between these pathways. Here, we report a novel mechanism linking IGF1-IGF1R and KITLG-KIT signaling in both normal and neoplastic cells. In murine gastric muscles, the microenvironment for ICC and GIST, human hepatic stellate cells (LX-2), a model for cancer niches, and GIST cells, IGF1 stimulated Kitl/KITLG protein and mRNA expression and promoter activity by activating several signaling pathways including AKT-mediated glycogen synthase kinase-3β inhibition (GSK3i). GSK3i alone also stimulated Kitl/KITLG expression without activating mitogenic pathways. Both IGF1 and GSK3i induced chromatin-level changes favoring transcriptional activation at the Kitl promoter including increased histone H3/H4 acetylation and H3 lysine (K) 4 methylation, reduced H3K9 and H3K27 methylation and reduced occupancy by the H3K27 methyltransferase EZH2. By pharmacological or RNA interference-mediated inhibition of chromatin modifiers we demonstrated that these changes have the predicted impact on KITLG expression. KITLG knock-down and immunoneutralization inhibited the proliferation of GIST cells expressing wild-type KIT, signifying oncogenic autocrine/paracrine KITLG-KIT signaling. We conclude that membrane-to-nucleus signaling involving GSK3i establishes a previously unrecognized link between the IGF1-IGF1R and KITLG-KIT pathways, which is active in both physiologic and oncogenic contexts and can be exploited for therapeutic purposes. PMID:24116170

  11. Lack of acidic fibroblast growth factor activation by heparan sulfate species from diabetic rat skin.

    PubMed

    Bourin, M C

    1997-06-01

    The glucosaminoglycans isolated from the skin of control and streptozotocin-diabetic rats were fractionated on ion-exchange chromatography into a heparan sulfate (HS)-like and a heparin-like species. In addition, a low sulfated fraction was isolated from the diabetics. The HS and heparin-like fractions isolated from the diabetics (in contrast to the low sulfated fractions) retained high affinity for the acidic (FGF-1) and basic (FGF-2) fibroblast growth factors. In culture, the fractions purified from the control rats and the heparin-like material isolated from the diabetics mediated the biological activity of both FGFs in a dose-dependent manner. By contrast, the diabetic HS-like fractions promoted the biological activity of FGF-2 but not of FGF-1. The results support the idea that the structural motives in HS required for FGF-1 and FGF-2 mediated receptor signalling are different. They may be relevant to the impaired wound healing observed in the disease.

  12. Neuropilin-1 mediates vascular permeability independently of vascular endothelial growth factor receptor-2 activation.

    PubMed

    Roth, Lise; Prahst, Claudia; Ruckdeschel, Tina; Savant, Soniya; Weström, Simone; Fantin, Alessandro; Riedel, Maria; Héroult, Mélanie; Ruhrberg, Christiana; Augustin, Hellmut G

    2016-04-26

    Neuropilin-1 (NRP1) regulates developmental and pathological angiogenesis, arteriogenesis, and vascular permeability, acting as a coreceptor for semaphorin 3A (Sema3A) and the 165-amino acid isoform of vascular endothelial growth factor A (VEGF-A165). NRP1 is also the receptor for the CendR peptides, a class of cell- and tissue-penetrating peptides with a specific R-x-x-R carboxyl-terminal motif. Because the cytoplasmic domain of NRP1 lacks catalytic activity, NRP1 is mainly thought to act through the recruitment and binding to other receptors. We report here that the NRP1 intracellular domain mediates vascular permeability. Stimulation with VEGF-A165, a ligand-blocking antibody, and a CendR peptide led to NRP1 accumulation at cell-cell contacts in endothelial cell monolayers, increased cellular permeability in vitro and vascular leakage in vivo. Biochemical analyses, VEGF receptor-2 (VEGFR-2) silencing, and the use of a specific VEGFR blocker established that the effects induced by the CendR peptide and the antibody were independent of VEGFR-2. Moreover, leakage assays in mice expressing a mutant NRP1 lacking the cytoplasmic domain revealed that this domain was required for NRP1-induced vascular permeability in vivo. Hence, these data define a vascular permeability pathway mediated by NRP1 but independent of VEGFR-2 activation.

  13. Enhanced dimerization drives ligand-independent activity of mutant epidermal growth factor receptor in lung cancer

    PubMed Central

    Valley, Christopher C.; Arndt-Jovin, Donna J.; Karedla, Narain; Steinkamp, Mara P.; Chizhik, Alexey I.; Hlavacek, William S.; Wilson, Bridget S.; Lidke, Keith A.; Lidke, Diane S.

    2015-01-01

    Mutations within the epidermal growth factor receptor (EGFR/erbB1/Her1) are often associated with tumorigenesis. In particular, a number of EGFR mutants that demonstrate ligand-independent signaling are common in non–small cell lung cancer (NSCLC), including kinase domain mutations L858R (also called L834R) and exon 19 deletions (e.g., ΔL747-P753insS), which collectively make up nearly 90% of mutations in NSCLC. The molecular mechanisms by which these mutations confer constitutive activity remain unresolved. Using multiple subdiffraction-limit imaging modalities, we reveal the altered receptor structure and interaction kinetics of NSCLC-associated EGFR mutants. We applied two-color single quantum dot tracking to quantify receptor dimerization kinetics on living cells and show that, in contrast to wild-type EGFR, mutants are capable of forming stable, ligand-independent dimers. Two-color superresolution localization microscopy confirmed ligand-independent aggregation of EGFR mutants. Live-cell Förster resonance energy transfer measurements revealed that the L858R kinase mutation alters ectodomain structure such that unliganded mutant EGFR adopts an extended, dimerization-competent conformation. Finally, mutation of the putative dimerization arm confirmed a critical role for ectodomain engagement in ligand-independent signaling. These data support a model in which dysregulated activity of NSCLC-associated kinase mutants is driven by coordinated interactions involving both the kinase and extracellular domains that lead to enhanced dimerization. PMID:26337388

  14. Insulin and insulin-like growth factor I exert different effects on plasminogen activator production or cell growth in the ovine thyroid cell line OVNIS.

    PubMed

    Degryse, B; Maisonobe, F; Hovsépian, S; Fayet, G

    1991-11-01

    Insulin and Insulin-like Growth Factor I (IGF-I) are evaluated for their capacity to affect cell proliferation and plasminogen activator (PA) activity production in an ovine thyroid cell line OVNIS. Insulin at physiological and supraphysiological doses induces cell proliferation and increases PA activity. IGF-I, which is also clearly mitogenic for these cells, surprisingly does not modulate PA activity. The results indicate that the growth promoting effect is mediated through the insulin and IGF-I receptors whereas PA activity is solely regulated via the insulin receptors. PMID:1802921

  15. Therapeutic effects of cell-permeant peptides that activate G proteins downstream of growth factors

    PubMed Central

    Ma, Gary S.; Aznar, Nicolas; Kalogriopoulos, Nicholas; Midde, Krishna K.; Lopez-Sanchez, Inmaculada; Sato, Emi; Dunkel, Ying; Gallo, Richard L.; Ghosh, Pradipta

    2015-01-01

    In eukaryotes, receptor tyrosine kinases (RTKs) and trimeric G proteins are two major signaling hubs. Signal transduction via trimeric G proteins has long been believed to be triggered exclusively by G protein-coupled receptors (GPCRs). This paradigm has recently been challenged by several studies on a multimodular signal transducer, Gα-Interacting Vesicle associated protein (GIV/Girdin). We recently demonstrated that GIV’s C terminus (CT) serves as a platform for dynamic association of ligand-activated RTKs with Gαi, and for noncanonical transactivation of G proteins. However, exogenous manipulation of this platform has remained beyond reach. Here we developed cell-permeable GIV-CT peptides by fusing a TAT-peptide transduction domain (TAT-PTD) to the minimal modular elements of GIV that are necessary and sufficient for activation of Gi downstream of RTKs, and used them to engineer signaling networks and alter cell behavior. In the presence of an intact GEF motif, TAT-GIV-CT peptides enhanced diverse processes in which GIV’s GEF function has previously been implicated, e.g., 2D cell migration after scratch-wounding, invasion of cancer cells, and finally, myofibroblast activation and collagen production. Furthermore, topical application of TAT-GIV-CT peptides enhanced the complex, multireceptor-driven process of wound repair in mice in a GEF-dependent manner. Thus, TAT-GIV peptides provide a novel and versatile tool to manipulate Gαi activation downstream of growth factors in a diverse array of pathophysiologic conditions. PMID:25926659

  16. Phosphorylation and Activation of RhoA by ERK in Response to Epidermal Growth Factor Stimulation

    PubMed Central

    Tong, Junfeng; Li, Laiji; Ballermann, Barbara; Wang, Zhixiang

    2016-01-01

    The small GTPase RhoA has been implicated in various cellular activities, including the formation of stress fibers, cell motility, and cytokinesis. In addition to the canonical GTPase cycle, recent findings have suggested that phosphorylation further contributes to the tight regulation of Rho GTPases. Indeed, RhoA is phosphorylated on serine 188 (188S) by a number of protein kinases. We have recently reported that Rac1 is phosphorylated on threonine 108 (108T) by extracellular signal-regulated kinases (ERK) in response to epidermal growth factor (EGF) stimulation. Here, we provide evidence that RhoA is phosphorylated by ERK on 88S and 100T in response to EGF stimulation. We show that ERK interacts with RhoA and that this interaction is dependent on the ERK docking site (D-site) at the C-terminus of RhoA. EGF stimulation enhanced the activation of the endogenous RhoA. The phosphomimetic mutant, GFP-RhoA S88E/T100E, when transiently expressed in COS-7 cells, displayed higher GTP-binding than wild type RhoA. Moreover, the expression of GFP-RhoA S88E/T100E increased actin stress fiber formation in COS-7 cells, which is consistent with its higher activity. In contrast to Rac1, phosphorylation of RhoA by ERK does not target RhoA to the nucleus. Finally, we show that regardless of the phosphorylation status of RhoA and Rac1, substitution of the RhoA PBR with the Rac1 PBR targets RhoA to the nucleus and substitution of Rac1 PBR with RhoA PBR significantly reduces the nuclear localization of Rac1. In conclusion, ERK phosphorylates RhoA on 88S and 100T in response to EGF, which upregulates RhoA activity. PMID:26816343

  17. [The development of a pharmacologically active low-molecular mimetic of the nerve growth factor].

    PubMed

    Seredenin, S B; Gudasheva, T A

    2015-01-01

    Authors present an overview of theirs author's works on the design of low-molecular mimetic of the nerve growth factor and studies of mechanisms of action and pharmacological properties of the compound. The original working hypothesis, underlying the design of the compound, posited that different neurotrophin hairpin loops could activate different signaling cascades by interaction with the receptor and so be responsible for different effects. The mimetic bis(N-succinyl-L-glutamyl-L-lysine)hexametylendiamide (GK-2), that was designed on the basis of NGF loop 4 β-turn sequence, activated TrkA and PI3K/Akt, but not MAPK/Erk. GK-2 showed neuroprotective activity in concentrations up to 10-9М against H(2)O(2) or glutamate or MPTP-induced neurotoxicity in РС12, НТ22 cells and primary rat hippocampal neurons. At that, GK-2 has no differentiating activity. In in vivo experiments, GK-2 exhibited significant anti-ischemic, anti-parkinsonic effect, reversed impaired cognitive functions in models of Alzheimer's disease in doses 0.01 - 5 mg/kg intraperitoneally and 5-10 mg/kg orally, but does not induce side effects accompanying the full-length neurotrophin treatment, which are hyperalgesia and weight loss. It was shown that GK-2 was a low-toxicity compound (LD50=700 mg/kg, intraperitoneally, mice) and capable of crossing the blood-brain barrier. The agent GK-2 is promising for development as a neuroprotective agent and is currently in preclinical studies. PMID:26356399

  18. Differential activation of mitogen-activated protein kinase in response to basic fibroblast growth factor in skeletal muscle cells.

    PubMed Central

    Campbell, J S; Wenderoth, M P; Hauschka, S D; Krebs, E G

    1995-01-01

    In the MM14 mouse myoblast cell line, fibroblast growth factor (FGF) stimulates proliferation and represses differentiation. However, the intracellular signaling pathways used by FGF to affect these cellular processes are unknown. The predominant FGF receptor present on MM14 cells, FGFR1, is a receptor tyrosine kinase capable of activating the mitogen-activated protein kinase (MAPK) cascade in fibroblast and neuronal cell lines. To determine whether the FGF signal is mediated via the MAPK cascade in myoblasts, MM14 cells were stimulated with basic FGF (bFGF) and activities of the various kinases were measured. After withdrawal from serum and bFGF for 3 hr, bFGF stimulated MAPK kinase (MAPKK) activity, but MAPK and S6 peptide kinase activities were not detected. In contrast, when serum and bFGF were withdrawn for 10 hr, the activities of MAPKK, MAPK, and S6 peptide kinase were all stimulated by bFGF treatment. The inability of bFGF to stimulate MAPK after 3 hr of withdrawal may be due, in part, to the presence of a MAPK phosphatase activity that was detected in MM14 cell extracts. This dephosphorylating activity diminishes during commitment to terminal differentiation and is inhibited by sodium orthovanadate. Thus, the ability of bFGF to stimulate MAPK in MM14 cells is correlated with the loss of a MAPK phosphatase activity. These results show that although bFGF activates MAPKK in proliferating myoblasts, the mitogenic signal does not progress to the downstream kinases, providing a physiological example of an uncoupling of the MAPK cascade. Images Fig. 4 Fig. 5 PMID:7846069

  19. Cross Talk between Neuroregulatory Molecule and Monocyte: Nerve Growth Factor Activates the Inflammasome

    PubMed Central

    Datta-Mitra, Ananya; Kundu-Raychaudhuri, Smriti; Mitra, Anupam; Raychaudhuri, Siba P.

    2015-01-01

    Background Increasing evidence points to a role for the extra-neuronal nerve growth factor (NGF) in acquired immune responses. However, very little information is available about its role and underlying mechanism in innate immunity. The role of innate immunity in autoimmune diseases is becoming increasingly important. In this study, we explored the contribution of pleiotropic NGF in the innate immune response along with its underlying molecular mechanism with respect to IL-1β secretion. Methods Human monocytes, null and NLRP3 deficient THP-1 cell lines were used for this purpose. We determined the effect of NGF on secretion of IL-1β at the protein and mRNA levels. To determine the underlying molecular mechanism, the effect of NGF on NLRP1/NLRP3 inflammasomes and its downstream key protein, activated caspase-1, were evaluated by ELISA, immunoflorescence, flow cytometry, and real-time PCR. Results In human monocytes and null THP-1 cell line, NGF significantly upregulates IL-1β at protein and mRNA levels in a caspase-1 dependent manner through its receptor, TrkA. Furthermore, we observed that NGF induces caspase-1 activation through NLRP1/NLRP3 inflammasomes, and it is dependent on the master transcription factor, NF-κB. Conclusions To best of our knowledge, this is the first report shedding light on the mechanistic aspect of a neuroregulatory molecule, NGF, in innate immune response, and thus enriches our understanding regarding its pathogenic role in inflammation. These observations add further evidence in favor of anti-NGF therapy in autoimmune diseases and also unlock a new area of research about the role of NGF in IL-1β mediated diseases. PMID:25876154

  20. Autocrine activities of basic fibroblast growth factor: regulation of endothelial cell movement, plasminogen activator synthesis, and DNA synthesis

    PubMed Central

    1988-01-01

    We have found that the spontaneous migration of bovine aortic endothelial cells from the edge of a denuded area in a confluent monolayer is dependent upon the release of endogenous basic fibroblast growth factor (bFGF). Cell movement is blocked by purified polyclonal rabbit IgG to bFGF as well as affinity purified anti-bFGF IgG and anti- bFGF F(ab')2 fragments. The inhibitory effect of the immunoglobulins is dependent upon antibody concentration, is reversible, is overcome by the addition of recombinant bFGF, and is removed by affinity chromatography of the antiserum through a column of bFGF-Sepharose. Cell movement is also reversibly inhibited by the addition of protamine sulfate and suramin; two agents reported to block bFGF binding to its receptor. The addition of recombinant bFGF to wounded monolayers accelerates the movement of cells into the denuded area. Transforming growth factor beta which has been shown to antagonize several other effects of bFGF also inhibits cell movement. The anti-bFGF IgG prevents the movement of bovine capillary endothelial cells, BHK-21, NIH 3T3, and human skin fibroblasts into a denuded area. Antibodies to bFGF, as well as suramin and protamine sulfate also suppress the basal levels of plasminogen activator and DNA synthesis in bovine aortic endothelial cells. PMID:3417781

  1. FGF growth factor analogs

    DOEpatents

    Zamora, Paul O.; Pena, Louis A.; Lin, Xinhua; Takahashi, Kazuyuki

    2012-07-24

    The present invention provides a fibroblast growth factor heparin-binding analog of the formula: ##STR00001## where R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, X, Y and Z are as defined, pharmaceutical compositions, coating compositions and medical devices including the fibroblast growth factor heparin-binding analog of the foregoing formula, and methods and uses thereof.

  2. The recombinant proregion of transforming growth factor beta1 (latency-associated peptide) inhibits active transforming growth factor beta1 in transgenic mice.

    PubMed

    Böttinger, E P; Factor, V M; Tsang, M L; Weatherbee, J A; Kopp, J B; Qian, S W; Wakefield, L M; Roberts, A B; Thorgeirsson, S S; Sporn, M B

    1996-06-11

    All three isoforms of transforming growth factors beta (TGF-betal, TGF-beta2, and TGF-beta3) are secreted as latent complexes and activated extracellularly, leading to the release of the mature cytokines from their noncovalently associated proregions, also known as latency-associated peptides (LAPs). The LAP region of TGF-beta1 was expressed in a baculovirus expression system and purified to homogeneity. In vitro assays of growth inhibition and gene induction mediated by TGF-beta3 demonstrate that recombinant TGF-beta1 LAP is a potent inhibitor of the activities of TGF-betal, -beta2, and -beta3. Effective dosages of LAP for 50% neutralization of TGF-beta activities range from 4.7- to 80-fold molar excess depending on the TGF-beta isoform and activity examined. Using 125I-labeled LAP, we show that the intraperitoneal application route is effective for systemic administration of LAP. Comparison of concentrations of LAP in tissues shows a homogenous pattern in most organs with the exception of heart and muscle, in which levels of LAP are 4- to 8-fold lower. In transgenic mice with elevated hepatic levels of bioactive TGF-betal, treatment with recombinant LAP completely reverses suppression of the early proliferative response induced by TGF-beta1 in remnant livers after partial hepatectomy. The results suggest that recombinant LAP is a potent inhibitor of bioactive TGF-beta both in vitro and in vivo, after intraperitoneal administration. Recombinant LAP should be a useful tool for novel approaches to study and therapeutically modulate pathophysiological processes mediated by TGF-beta3.

  3. Nerve growth factor in the hippocamposeptal system: evidence for activity-dependent anterograde delivery and modulation of synaptic activity.

    PubMed

    Guo, Lan; Yeh, Mason L; Cuzon Carlson, Verginia C; Johnson-Venkatesh, Erin M; Yeh, Hermes H

    2012-05-30

    Neurotrophins have been implicated in regulating neuronal differentiation, promoting neuronal survival, and modulating synaptic efficacy and plasticity. The prevailing view is that, depending on the target and mode of action, most neurotrophins can be trafficked and released either anterogradely or retrogradely in an activity-dependent manner. However, the prototypic neurotrophin, nerve growth factor (NGF), is not thought to be anterogradely delivered. Here we provide the neuroanatomical substrate for an anterograde hippocamposeptal transport of NGF by demonstrating its presence in mouse hippocampal GABAergic neurons and in their hippocamposeptal axons that ramify densely and abut neurons in the medial septum/diagonal band of Broca (MS/DB). We also demonstrate an activity-dependent increase in septal NGF levels that is dependent on the pattern of intrahippocampal stimulation. In addition, we show that acute exposure to NGF, via activation of TrkA, attenuates GABA(A) receptor-mediated inhibitory synaptic currents and reduces sensitivity to exogenously applied GABA. These acute actions of NGF display cell type and functional selectivity insofar as (1) they were found in cholinergic, but not GABAergic, MS/DB neurons, and (2) glutamate-mediated excitatory synaptic activity as well as AMPA-activated current responses were unaffected. Our results advocate a novel anterograde, TrkA-mediated NGF signaling in the CNS. PMID:22649248

  4. Negative feedback regulation and desensitization of insulin- and epidermal growth factor-stimulated p21ras activation.

    PubMed

    Langlois, W J; Sasaoka, T; Saltiel, A R; Olefsky, J M

    1995-10-27

    Insulin and epidermal growth factor receptors transmit signals for cell proliferation and gene regulation through formation of active GTP-bound p21ras mediated by the guanine nucleotide exchange factor Sos. Sos is constitutively bound to the adaptor protein Grb2 and growth factor stimulation induces association of the Grb2/Sos complex with Shc and movement of Sos to the plasma membrane location of p21ras. Insulin or epidermal growth factor stimulation induces a rapid increase in p21ras levels, but after several minutes levels decline toward basal despite ongoing hormone stimulation. Here we show that deactivation of p21ras correlates closely with phosphorylation of Sos and dissociation of Sos from Grb2, and that inhibition of mitogen-activated protein (MAP) kinase kinase (also known as extracellular signal-related kinase (ERK) kinase, or MEK) blocks both events, resulting in prolonged p21ras activation. These data suggest that a negative feedback loop exists whereby activation of the Raf/MEK/MAP kinase cascade by p21ras causes Sos phosphorylation and, therefore, Sos/Grb2 dissociation, limiting the duration of p21ras activation by growth factors. A serine/threonine kinase downstream of MEK (probably MAP kinase) mediates this desensitization feedback pathway.

  5. Recombinant insulin-like growth factor-1 activates satellite cells in the mouse urethral rhabdosphincter

    PubMed Central

    2013-01-01

    Background The goal of this study is to demonstrate the efficacy of a new method for the treatment of urinary incontinence by stimulation of urethral rhabdosphincter satellite cells. We show that satellite cells do exist in the sphincter muscle of retired male mice breeders by staining for c-Met, a satellite cell specific protein. Once activated by recombinant mouse Insulin-like Growth Factor-1(rIgf-1), the satellite cells develop into muscle cells within the rhabdosphincter thereby potentially strengthening it. Methods 20 μl (1 μg/μl) of rIgf-1 was surgically injected directly into the urethral wall of retired male mouse breeders. Mice injected with phosphate buffered saline (PBS) were used as controls. 4 weeks later, urethras were harvested and serially-sectioned through the sphincter for routine hematoxylin-eosin staining as well as immunohistochemical staining with satellite cell specific anti-c-Met antibody and proliferation specific anti-Ki-67 antibody. Results Anti-c-Met antibody positive cells (c-Met+) were identified in the rhabdosphincter. c-Met+ cells increased by 161.8% relative to controls four weeks after rIGF-1 injection. Anti- Ki-67 antibody positive cells were identified and characterized as cells with centrally located nuclei in striated muscle bundles of rIGF-1 treated animals. Conclusions Satellite cells in the mouse rhabdosphincter can be activated by rIGF-1 treatment, which subsequently are incorporated into existing skeletal muscle bundles. Using this approach, the rhabdosphincter can be induced to regenerate and potentially strengthen via satellite cell activation and likely improve urinary continence. PMID:24279352

  6. Rapidly activated epidermal growth factor receptor mediates lipopolysaccharide-triggered migration of microglia.

    PubMed

    Qu, Wen-Sheng; Liu, Jun-Li; Li, Chun-Yu; Li, Xiao; Xie, Min-Jie; Wang, Wei; Tian, Dai-Shi

    2015-11-01

    Previous reports have suggested that epidermal growth factor receptor (EGFR) is involved in microglia activation characterized by cell morphology changes, cytokine production and cell migration; and the biochemical regulation of the microglia migration is a potential therapeutic target following CNS inflammatory damages. However, the role of EGFR in microglia motility after inflammatory stimulation remains unknown. In the present study, lipopolysaccharide (LPS) was found to trigger rapid EGFR phosphorylation within 10 min, which was sustained during long-term stimulation in both primary microglial cells and the cultured BV2 microglial cells, furthermore, blocking EGFR phosphorylation by AG1478 significantly attenuated the LPS-induced chemotactic and chemokinetic migration of microglia. In addition, LPS could initiate calcium oscillation in microglia during live-cell recording, however, an intracellular calcium chelator and a selective inhibitor of calcium/calmodulin-dependent protein kinase II, but not an extracellular calcium chelator, remarkably suppressed the LPS-induced EGFR phosphorylation in BV2 microglia cells. As EGFR is not a traditional receptor for LPS, these findings suggest that the rapid phosphorylation of EGFR is attributed to the LPS-triggered intracellular calcium mobilization. By examining the downstream signals of EGFR, we further proved that extracellular signal-regulated kinase (ERK) is essential for EGFR-mediated microglia migration, because ERK inhibition attenuated the chemotactic and chemokinetic migration of microglia that had been induced by either LPS or EGF. Collectively, these results suggest that LPS could trigger the rapid phosphorylation of EGFR and subsequent ERK activation through mobilizing calcium activity, which underlies the microglia migration in an inflammatory condition.

  7. Production of Gastrointestinal Tumors in Mice by Modulating Latent Transforming Growth Factor Beta 1 Activation

    PubMed Central

    Shibahara, Kotaro; Ota, Mitsuhiko; Horiguchi, Masahito; Yoshinaga, Keiji; Melamed, Jonathan; Rifkin, Daniel B

    2012-01-01

    Transforming growth factor-β (TGF-β) and its signaling pathways are important mediators in the suppression of cancers of the gastrointestinal (GI) tract. TGF-β is released from cells in a latent complex consisting of TGF-β, the TGF-β propeptide (LAP) and a latent TGF-β binding protein (LTBP). We previously generated mice in which the LTBP-binding cysteine residues in LAP TGF-β1 were mutated to serine precluding covalent interactions with LTBP. These Tgfb1C33S/C33S mice develop multiorgan inflammation and tumors consistent with reduced TGF-β1 activity. To test whether further reduction in active TGF-β levels would yield additional tumors and a phenotype more similar to Tgfb1-/- mice, we generated mice that express TGF-β1C33S and are deficient in either integrin β8 or TSP-1, known activators of latent TGF-β1. In addition we generated mice that have one mutant allele and one null allele at the Tgfb1 locus, reasoning that these mice should synthesize half the total amount of TGF-β1 as Tgfb1C33S/C33S mice and the amount of active TGF-β1 would be correspondingly decreased compared to Tgfb1C33S/C33S mice. These compound mutant mice displayed more severe inflammation and higher tumor numbers than the parental Tgfb1C33S/C33S animals. The level of active TGF-β1 in compound mutant mice appeared to be decreased compared to Tgfb1C33S/C33S mice as determined from analyses of surrogate markers of active TGF-β, such as P-Smad2, C-Myc, KI-67, and markers of cell cycle traverse. We conclude that these mutant mice provide a useful system for modulating TGF-β levels in a manner that determines tumor number and inflammation within the GI tract. PMID:23117884

  8. Growth factors for nanobacteria

    NASA Astrophysics Data System (ADS)

    Ciftcioglu, Neva; Kajander, E. Olavi

    1999-12-01

    Nanobacteria are novel microorganisms recently isolated from fetal bovine serum and blood of cows and humans. These coccoid, gram negative bacteria in alpha-2 subgroup of Proteobacteria grow slowly under mammalian cell culture conditions but not in common media for microbes. Now we have found two different kinds of culture supplement preparations that improve their growth and make them culturable in the classical sense. These are supernatant fractions of conditioned media obtained from 1 - 3 months old nanobacteria cultures and from about a 2 weeks old Bacillus species culture. Both improved multiplication and particle yields and the latter increased their resistance to gentamicin. Nanobacteria cultured with any of the methods shared similar immunological property, structure and protein pattern. The growth supporting factors were heat-stabile and nondialyzable, and dialysis improved the growth promoting action. Nanobacteria formed stony colonies in a bacteriological medium supplemented with the growth factors. This is an implication that nanobacterial growth is influenced by pre-existing bacterial flora.

  9. Oncogenic Human Papillomaviruses Activate the Tumor-Associated Lens Epithelial-Derived Growth Factor (LEDGF) Gene

    PubMed Central

    Leitz, Jenny; Reuschenbach, Miriam; Lohrey, Claudia; Honegger, Anja; Accardi, Rosita; Tommasino, Massimo; Llano, Manuel; von Knebel Doeberitz, Magnus; Hoppe-Seyler, Karin; Hoppe-Seyler, Felix

    2014-01-01

    The expression of the human papillomavirus (HPV) E6/E7 oncogenes is crucial for HPV-induced malignant cell transformation. The identification of cellular targets attacked by the HPV oncogenes is critical for our understanding of the molecular mechanisms of HPV-associated carcinogenesis and may open novel therapeutic opportunities. Here, we identify the Lens Epithelial-Derived Growth Factor (LEDGF) gene as a novel cellular target gene for the HPV oncogenes. Elevated LEDGF expression has been recently linked to human carcinogenesis and can protect tumor cells towards different forms of cellular stress. We show that intracellular LEDGF mRNA and protein levels in HPV-positive cancer cells are critically dependent on the maintenance of viral oncogene expression. Ectopic E6/E7 expression stimulates LEDGF transcription in primary keratinocytes, at least in part via activation of the LEDGF promoter. Repression of endogenous LEDGF expression by RNA interference results in an increased sensitivity of HPV-positive cancer cells towards genotoxic agents. Immunohistochemical analyses of cervical tissue specimens reveal a highly significant increase of LEDGF protein levels in HPV-positive lesions compared to histologically normal cervical epithelium. Taken together, these results indicate that the E6/E7-dependent maintenance of intracellular LEDGF expression is critical for protecting HPV-positive cancer cells against various forms of cellular stress, including DNA damage. This could support tumor cell survival and contribute to the therapeutic resistance of cervical cancers towards genotoxic treatment strategies in the clinic. PMID:24604027

  10. Oncogenic human papillomaviruses activate the tumor-associated lens epithelial-derived growth factor (LEDGF) gene.

    PubMed

    Leitz, Jenny; Reuschenbach, Miriam; Lohrey, Claudia; Honegger, Anja; Accardi, Rosita; Tommasino, Massimo; Llano, Manuel; von Knebel Doeberitz, Magnus; Hoppe-Seyler, Karin; Hoppe-Seyler, Felix

    2014-03-01

    The expression of the human papillomavirus (HPV) E6/E7 oncogenes is crucial for HPV-induced malignant cell transformation. The identification of cellular targets attacked by the HPV oncogenes is critical for our understanding of the molecular mechanisms of HPV-associated carcinogenesis and may open novel therapeutic opportunities. Here, we identify the Lens Epithelial-Derived Growth Factor (LEDGF) gene as a novel cellular target gene for the HPV oncogenes. Elevated LEDGF expression has been recently linked to human carcinogenesis and can protect tumor cells towards different forms of cellular stress. We show that intracellular LEDGF mRNA and protein levels in HPV-positive cancer cells are critically dependent on the maintenance of viral oncogene expression. Ectopic E6/E7 expression stimulates LEDGF transcription in primary keratinocytes, at least in part via activation of the LEDGF promoter. Repression of endogenous LEDGF expression by RNA interference results in an increased sensitivity of HPV-positive cancer cells towards genotoxic agents. Immunohistochemical analyses of cervical tissue specimens reveal a highly significant increase of LEDGF protein levels in HPV-positive lesions compared to histologically normal cervical epithelium. Taken together, these results indicate that the E6/E7-dependent maintenance of intracellular LEDGF expression is critical for protecting HPV-positive cancer cells against various forms of cellular stress, including DNA damage. This could support tumor cell survival and contribute to the therapeutic resistance of cervical cancers towards genotoxic treatment strategies in the clinic.

  11. The activation of fibroblast growth factors by heparin: synthesis, structure, and biological activity of heparin-like oligosaccharides.

    PubMed

    de Paz, J L; Angulo, J; Lassaletta, J M; Nieto, P M; Redondo-Horcajo, M; Lozano, R M; Giménez-Gallego, G; Martín-Lomas, M

    2001-09-01

    An effective strategy has been designed for the synthesis of oligosaccharides of different sizes structurally related to the regular region of heparin; this is illustrated by the preparation of hexasaccharide 1 and octasaccharide 2. This synthetic strategy provides the oligosaccharide sequence containing a D-glucosamine unit at the nonreducing end that is not available either by enzymatic or chemical degradation of heparin. It may permit, after slight modifications, the preparation of oligosaccharide fragments with different charge distribution as well. NMR spectroscopy and molecular dynamics simulations have shown that the overall structure of 1 in solution is a stable right-hand helix with four residues per turn. Hexasaccharide 1 and, most likely, octasaccharide 2 are, therefore, chemically well-defined structural models of naturally occurring heparin-like oligosaccharides for use in binding and biological activity studies. Both compounds 1 and 2 induce the mitogenic activity of acid fibroblast growth factor (FGF1), with the half-maximum activating concentration of 2 being equivalent to that of heparin. Sedimentation equilibrium analysis with compound 2 suggests that heparin-induced FGF1 dimerization is not an absolute requirement for biological activity. PMID:11828504

  12. Nerve growth factor enhances the CRE-dependent transcriptional activity activated by nobiletin in PC12 cells.

    PubMed

    Takito, Jiro; Kimura, Junko; Kajima, Koji; Uozumi, Nobuyuki; Watanabe, Makoto; Yokosuka, Akihito; Mimaki, Yoshihiro; Nakamura, Masanori; Ohizumi, Yasushi

    2016-07-01

    Prevention and treatment of Alzheimer disease are urgent problems for elderly people in developed countries. We previously reported that nobiletin, a poly-methoxylated flavone from the citrus peel, improved the symptoms in various types of animal models of memory loss and activated the cAMP responsive element (CRE)-dependent transcription in PC12 cells. Nobiletin activated the cAMP/PKA/MEK/Erk/MAPK signaling pathway without using the TrkA signaling activated by nerve growth factor (NGF). Here, we examined the effect of combination of nobiletin and NGF on the CRE-dependent transcription in PC12 cells. Although NGF alone had little effect on the CRE-dependent transcription, NGF markedly enhanced the CRE-dependent transcription induced by nobiletin. The NGF-induced enhancement was neutralized by a TrkA antagonist, K252a. This effect of NGF was effective on the early signaling event elicited by nobiletin. These results suggested that there was crosstalk between NGF and nobiletin signaling in activating the CRE-dependent transcription in PC12 cells.

  13. The activation of fibroblast growth factors by heparin: synthesis, structure, and biological activity of heparin-like oligosaccharides.

    PubMed

    de Paz, J L; Angulo, J; Lassaletta, J M; Nieto, P M; Redondo-Horcajo, M; Lozano, R M; Giménez-Gallego, G; Martín-Lomas, M

    2001-09-01

    An effective strategy has been designed for the synthesis of oligosaccharides of different sizes structurally related to the regular region of heparin; this is illustrated by the preparation of hexasaccharide 1 and octasaccharide 2. This synthetic strategy provides the oligosaccharide sequence containing a D-glucosamine unit at the nonreducing end that is not available either by enzymatic or chemical degradation of heparin. It may permit, after slight modifications, the preparation of oligosaccharide fragments with different charge distribution as well. NMR spectroscopy and molecular dynamics simulations have shown that the overall structure of 1 in solution is a stable right-hand helix with four residues per turn. Hexasaccharide 1 and, most likely, octasaccharide 2 are, therefore, chemically well-defined structural models of naturally occurring heparin-like oligosaccharides for use in binding and biological activity studies. Both compounds 1 and 2 induce the mitogenic activity of acid fibroblast growth factor (FGF1), with the half-maximum activating concentration of 2 being equivalent to that of heparin. Sedimentation equilibrium analysis with compound 2 suggests that heparin-induced FGF1 dimerization is not an absolute requirement for biological activity.

  14. Nerve growth factor alters the sensitivity of rat masseter muscle mechanoreceptors to NMDA receptor activation.

    PubMed

    Wong, Hayes; Dong, Xu-Dong; Cairns, Brian E

    2014-11-01

    Intramuscular injection of nerve growth factor (NGF) into rat masseter muscle induces a local mechanical sensitization that is greater in female than in male rats. The duration of NGF-induced sensitization in male and female rats was associated with an increase in peripheral N-methyl-d-aspartate (NMDA) receptor expression by masseter muscle afferent fibers that began 3 days postinjection. Here, we investigated the functional consequences of increased NMDA expression on the response properties of masseter muscle mechanoreceptors. In vivo extracellular single-unit electrophysiological recordings of trigeminal ganglion neurons innervating the masseter muscle were performed in anesthetized rats 3 days after NGF injection (25 μg/ml, 10 μl) into the masseter muscle. Mechanical activation threshold was assessed before and after intramuscular injection of NMDA. NMDA injection induced mechanical sensitization in both sexes that was increased significantly following NGF injection in the male rats but not in the female rats. However, in female but not male rats, further examination found that preadministration of NGF induced a greater sensitization in slow Aδ-fibers (2-7 m/s) than fast Aδ-fibers (7-12 m/s). This suggests that preadministration of NGF had a different effect on slowly conducting mechanoreceptors in the female rats compared with the male rats. Although previous studies have found an association between estrogenic tone and NMDA activity, no correlation was observed between NMDA-evoked mechanical sensitization and plasma estrogen level. This study suggests NGF alters NMDA-induced mechanical sensitization in the peripheral endings of masseter mechanoreceptors in a sexually dimorphic manner.

  15. Invasive candidiasis stimulates hepatocyte and monocyte production of active transforming growth factor beta.

    PubMed

    Letterio, J J; Lehrnbecher, T; Pollack, G; Walsh, T J; Chanock, S J

    2001-08-01

    Candida albicans is an opportunistic fungal pathogen and a major cause of morbidity and mortality in patients with compromised immune function. The cytokine response to tissue invasion by C. albicans can influence the differentiation and function of lymphocytes and other mononuclear cells that are critical components of the host response. While the production of transforming growth factor beta (TGF-beta) has been documented in mice infected with C. albicans and is known to suppress phagocyte function, the cellular source and role of this cytokine in the pathogenesis of systemic candidiasis are not well understood. We have investigated the source of production of TGF-beta by immunohistochemical studies in tissue samples from patients with an uncommon complication of lymphoreticular malignancy, chronic disseminated candidiasis (CDC), and from a neutropenic-rabbit model of CDC. Liver biopsy specimens from patients with documented CDC demonstrated intense staining for extracellular matrix-associated TGF-beta1 within inflammatory granulomas, as well as staining for TGF-beta1 and TGF-beta3 within adjacent hepatocytes. These results correlate with the immunolocalization of TGF-beta observed in livers of infected neutropenic rabbits, using a neutralizing antibody that recognizes the mature TGF-beta protein. Human peripheral blood monocytes incubated with C. albicans in vitro release large amounts of biologically active TGF-beta1. The data demonstrate that local production of active TGF-betas by hepatocytes and by infected mononuclear cells is a component of the response to C. albicans infection that most probably contributes to disease progression in the immunocompromised host.

  16. Transforming growth factor β signaling upregulates the expression of human GDP-fucose transporter by activating transcription factor Sp1.

    PubMed

    Xu, Yu-Xin; Ma, Anna; Liu, Li

    2013-01-01

    GDP-fucose transporter plays a crucial role in fucosylation of glycoproteins by providing activated fucose donor, GDP-fucose, for fucosyltransferases in the lumen of the Golgi apparatus. Fucose-containing glycans are involved in many biological processes, which are essential for growth and development. Mutations in the GDP-fucose transporter gene cause leukocyte adhesion deficiency syndrome II, a disease characterized by slow growth, mental retardation and immunodeficiency. However, no information is available regarding its transcriptional regulation. Here, by using human cells, we show that TGF-β1 specifically induces the GDP-fucose transporter expression, but not other transporters tested such as CMP-sialic acid transporter, suggesting a diversity of regulatory pathways for the expression of these transporters. The regulatory elements that are responsive to the TGF-β1 stimulation are present in the region between bp -330 and -268 in the GDP-fucose transporter promoter. We found that this region contains two identical octamer GC-rich motifs (GGGGCGTG) that were demonstrated to be essential for the transporter expression. We also show that the transcription factor Sp1 specifically binds to the GC-rich motifs in vitro and Sp1 coupled with phospho-Smad2 is associated with the promoter region covering the Sp1-binding motifs in vivo using chromatin immunoprecipitation (ChIP) assays. In addition, we further confirmed that Sp1 is essential for the GDP-fucose transporter expression stimulated by TGF-β1 using a luciferase reporter system. These results highlight the role of TGF-β signaling in regulation of the GDP-fucose transporter expression via activating Sp1. This is the first transcriptional study for any nucleotide sugar transporters that have been identified so far. Notably, TGF-β1 receptor itself is known to be modified by fucosylation. Given the essential role of GDP-fucose transporter in fucosylation, the finding that TGF-β1 stimulates the expression of

  17. Epidermal growth factor-like repeats of tenascin-C-induced constriction of cerebral arteries via activation of epidermal growth factor receptors in rats.

    PubMed

    Fujimoto, Masashi; Shiba, Masato; Kawakita, Fumihiro; Liu, Lei; Nakasaki, Asuka; Shimojo, Naoshi; Imanaka-Yoshida, Kyoko; Yoshida, Toshimichi; Suzuki, Hidenori

    2016-07-01

    Tenascin-C (TNC), one of matricellular proteins, has been suggested to be involved in cerebral vasospasm after aneurysmal subarachnoid hemorrhage. However, the mechanisms of how TNC constricts cerebral arteries remain unclear. The aim of this study was to examine if epidermal growth factor (EGF)-like repeats of TNC is involved in TNC-induced constriction of cerebral arteries in rats via EGF receptor (EGFR) activation. Two dosages of recombinant TNC (r-TNC) consisting of the EGF-like repeats was administered intracisternally to healthy rats, and its vasoconstrictor effects were evaluated by neurobehavioral tests and India-ink angiography at 24, 48, and 72 hours after the administration. Western blotting and immunohistochemistry were performed to explore the underlying mechanisms on constricted cerebral arteries after 24 hours. The effects of a selective EGFR tyrosine kinase inhibitor (AG1478) on r-TNC-induced vasoconstriction were evaluated by neurobehavioral tests, India-ink angiography and immunohistochemistry at 24 hours after the administration. A higher dosage of r-TNC induced cerebral arterial constriction more severely, which continued for 48 hours. The effects were associated with the activation of EGFR and extracellular signal-regulated kinase (ERK)1/2 in the smooth muscle cell layer of the constricted cerebral artery, while c-Jun N-terminal kinase and p38 were not activated. AG1478 blocked r-TNC-induced vasoconstrictive effects, as well as activation of EGFR and ERK1/2. These findings demonstrate that TNC induces constriction of cerebral arteries via activation of EGFR and ERK1/2.

  18. Urinary active transforming growth factor β in feline chronic kidney disease.

    PubMed

    Lawson, J S; Syme, H M; Wheeler-Jones, C P D; Elliott, J

    2016-08-01

    The cytokine transforming growth factor beta 1 (TGF-β1) has been widely implicated in the development and progression of renal fibrosis in chronic kidney disease (CKD) in humans and in experimental models. The aims of this study were to assess the association between urinary active TGF-β1 and (a) development of CKD in a cross-sectional study, (b) deterioration of renal function over 1 year in a longitudinal study, and (c) renal histopathological parameters in cats. A human active TGF-β1 ELISA was validated for use in feline urine. Cross-sectional analysis revealed no significant difference in urinary active TGF-β1:creatinine ratio (aTGF-β1:UCr) between groups with differing renal function. Longitudinally, non-azotaemic cats that developed CKD demonstrated a significant (P = 0.028) increase in aTGF-β1:UCr approximately 6 months before the development of azotaemia, which remained elevated (P = 0.046) at diagnosis (approximately 12 months prior, 8.4 pg/mg; approximately 6 months prior, 22.2 pg/mg; at CKD diagnosis, 24.6 pg/mg). In the histopathology study, aTGF-β1:UCr was significantly higher in cats with moderate (P = 0.02) and diffuse (P = 0.005) renal fibrosis than in cats without fibrosis. Cats with moderate renal inflammation had significantly higher urinary active aTGF-β1 concentrations than cats with mild (P = 0.035) or no inflammatory change (P = 0.004). The parameter aTGF-β1:UCr was independently associated with Log urine protein:creatinine ratio in a multivariable analysis of clinicopathological parameters and interstitial fibrosis score in a multivariable analysis of histopathological features. These results suggest that urinary aTGF-β1 reflects the severity of renal pathology. Increases in urinary aTGF-β1 followed longitudinally in individual cats may indicate the development of CKD. PMID:27387717

  19. Chronic nerve growth factor administration increases the peripheral exocytotic activity of capsaicin-sensitive cutaneous neurons.

    PubMed

    Bowles, Walter R; Sabino, Ma'lou; Harding-Rose, Catherine; Hargreaves, Kenneth M

    2006-08-01

    Nerve growth factor (NGF) plays an important role in inflammation and pain and has been suggested to regulate the responsiveness and sensitivity of nociceptive fibers. However, no study has evaluated whether chronic NGF alters the exocytotic capacity of peripheral terminals of peptidergic fibers. To test this hypothesis, rats were injected subcutaneously every other day with either murine recombinant NGF (mNGF; 1.0 mg/kg) or vehicle for 7 days; or mNGF (0.1 mg/kg), mNGF (1 mg/kg) or vehicle every other day for 13 days. Treatment of rats with NGF over a 13-day period produced a significant increase in capsaicin-evoked iCGRP release from isolated biopsies of hindpaw skin, as assessed by in vitro superfusion and RIA. This effect was dose-dependent and exhibited a temporal requirement, because the enhancement was only observed after 13 days of treatment and was not evident after 7 days of treatment. This NGF enhancement of capsaicin-evoked iCGRP release was not due solely to increases in peripheral iCGRP content since only the 1mg/kg dose of NGF elevated cutaneous pools of iCGRP, whereas both doses significantly increased capsaicin-evoked peptide release. Moreover, NGF also enhanced capsaicin-evoked thermal hyperalgesia under similar dose- and time-related conditions. Collectively, the chronic administration of NGF not only increases capsaicin-evoked hyperalgesia, but also significantly primes peripheral fibers to enhanced peptidergic exocytosis following activation of the capsaicin receptor. Collectively, these data are consistent with the hypothesis that persistently elevated NGF levels may contribute to enhanced neurogenic regulation of inflammatory and wound healing processes in injured tissue.

  20. Effects of cell heterogeneity on production of polypeptide growth factors and mesoderm-inducing activity by Xenopus laevis XTC cells.

    PubMed

    Snoek, G T; Koster, C H; de Laat, S W; Heideveld, M; Durston, A J; van Zoelen, E J

    1990-04-01

    The Xenopus laevis XTC cell line has been analyzed for the production of polypeptide growth factors and mesoderm-inducing activity. By the use of specific biological assays, it is shown that XTC cells produce a growth factor functionally related to the platelet-derived growth factor (PDGF) and two transforming growth factor (TGF) beta-like activities. Mesoderm-inducing activity, as measured on X. laevis ectodermal explants from stage 10 embryos, was found to coelute on a Bio-Gel P-100 column with one of the TGF beta-like activities at an apparent molecular weight of 6-10 kDa. Analysis of the DNA content from XTC cells by flow cytometry demonstrated that the cell line is heterogeneous and consists of both tetraploid and diploid cells. Cloning of the XTC cells and selecting single-cell colonies on the basis of their ability to grow in soft agar resulted in the isolation of several homogeneous, morphologically different clonal derivatives. Analysis of conditioned medium from these clonal derivatives showed that only one of them, the only diploid line among six investigated, produced a strong heat- and acid-stable mesoderm-inducing activity that induced notochord and muscle formation in stage 10 X. laevis ectodermal explants. The relation between this activity and a recently described TGF beta-like mesoderm-inducing factor obtained from XTC-conditioned medium will be discussed. In conclusion, a clonal cell line derived from X. laevis XTC cells which provides a good source for further characterization of mesoderm-inducing factors has been established.

  1. The product of a novel growth factor activated gene, fos B, interacts with JUN proteins enhancing their DNA binding activity.

    PubMed Central

    Zerial, M; Toschi, L; Ryseck, R P; Schuermann, M; Müller, R; Bravo, R

    1989-01-01

    We have identified a gene, fos B, encoding a nuclear protein of 338 amino acids presenting a 70% homology with c-fos, whose expression is activated during G0/G1 transition. Growth factor stimulation of quiescent cells leads to a rapid and transient accumulation of fos B mRNA, with kinetics similar to those of c-fos. The induction of fos B mRNA levels is in part due to a dramatic increase in the transcription of the gene. The half-life of fos B mRNA is in the order of 10-15 min. Both transcriptional activation and mRNA stability are substantially increased in the presence of protein synthesis inhibitors. Immunoprecipitation studies showed that fos B as c-fos protein, forms a complex in vitro with c-jun and jun B proteins in the absence of a target binding sequence. Gel retardation assays demonstrated that fos B protein positively influences the binding of c-jun and jun B proteins to an AP-1 binding consensus sequence, suggesting that fos B protein plays a role in control of gene expression. Images PMID:2498083

  2. Platelet and growth factor concentrations in activated platelet-rich plasma: a comparison of seven commercial separation systems.

    PubMed

    Kushida, Satoshi; Kakudo, Natsuko; Morimoto, Naoki; Hara, Tomoya; Ogawa, Takeshi; Mitsui, Toshihito; Kusumoto, Kenji

    2014-06-01

    Platelet-rich plasma (PRP) is blood plasma that has been enriched with platelets. It holds promise for clinical use in areas such as wound healing and regenerative medicine, including bone regeneration. This study characterized the composition of PRP produced by seven commercially available separation systems (JP200, GLO PRP, Magellan Autologous Platelet Separator System, KYOCERA Medical PRP Kit, SELPHYL, MyCells, and Dr. Shin's System THROMBO KIT) to evaluate the platelet, white blood cell, red blood cell, and growth factor concentrations, as well as platelet-derived growth factor-AB (PDGF-AB), transforming growth factor beta-1 (TGF-β1), and vascular endothelial growth factor (VEGF) concentrations. PRP prepared using the Magellan Autologous Platelet Separator System and the KYOCERA Medical PRP Kit contained the highest platelet concentrations. The mean PDGF-AB concentration of activated PRP was the highest from JP200, followed by the KYOCERA Medical PRP Kit, Magellan Autologous Platelet Separator System, MyCells, and GLO PRP. TGF-β1 and VEGF concentrations varied greatly among individual samples, and there was almost no significant difference among the different systems, unlike for PDGF. The SELPHYL system produced PRP with low concentrations of both platelets and growth factors. Commercial PRP separation systems vary widely, and familiarity with their individual advantages is important to extend their clinical application to a wide variety of conditions.

  3. Hepatocyte growth factor/cMET pathway activation enhances cancer hallmarks in adrenocortical carcinoma

    PubMed Central

    Phan, Liem M.; Fuentes-Mattei, Enrique; Wu, Weixin; Velazquez-Torres, Guermarie; Sircar, Kanishka; Wood, Christopher G.; Hai, Tao; Jimenez, Camilo; Cote, Gilbert J.; Ozsari, Levent; Hofmann, Marie-Claude; Zheng, Siyuan; Verhaak, Roeland; Pagliaro, Lance; Cortez, Maria Angelica; Lee, Mong-Hong; Yeung, Sai-Ching J.; Habra, Mouhammed Amir

    2015-01-01

    Adrenocortical carcinoma (ACC) is a rare malignancy with poor prognosis and limited response to chemotherapy. Hepatocyte growth factor (HGF) and its receptor cMET augment cancer growth and resistance to chemotherapy, but their role in ACC has not been examined. In this study, we investigated the association between HGF/cMET expression and cancer hallmarks of ACC. Transcriptomic and immunohistochemical analyses indicated that increased HGF/cMET expression in human ACC samples was positively associated with cancer-related biological processes including proliferation and angiogenesis, and negatively correlated with apoptosis. Accordingly, treatment of ACC cells with exogenous HCG resulted in increased cell proliferation in vitro and in vivo while short hairpin RNA-mediated knockdown or pharmacological inhibition of cMET suppressed cell proliferation and tumor growth. Moreover, exposure of cells to mitotane, cisplatin, or radiation rapidly induced pro-cMET expression and was associated with an enrichment of genes (e.g., CYP450 family) related to therapy resistance further implicating cMET in the anticancer drug response. Together, these data suggest an important role for HGF/cMET signaling in ACC growth and resistance to commonly used treatments. Targeting cMET, alone or in combination with other drugs, could provide a breakthrough in the management of this aggressive cancer. PMID:26282167

  4. Activation of Epidermal Growth Factor Receptor in Macrophages Mediates Feedback Inhibition of M2 Polarization and Gastrointestinal Tumor Cell Growth.

    PubMed

    Zhao, Gang; Liu, Liping; Peek, Richard M; Hao, Xishan; Polk, D Brent; Li, Hui; Yan, Fang

    2016-09-23

    EGF receptor (EGFR) in tumor cells serves as a tumor promoter. However, information about EGFR activation in macrophages in regulating M2 polarization and tumor development is limited. This study aimed to investigate the effects of EGFR activation in macrophages on M2 polarization and development of gastrointestinal tumors. IL-4, a cytokine to elicit M2 polarization, stimulated release of an EGFR ligand, HB-EGF, and transactivation and down-regulation of EGFR in Raw 264.7 cells and peritoneal macrophages from WT mice. Knockdown of HB-EGF in macrophages inhibited EGFR transactivation by IL-4. IL-4-stimulated STAT6 activation, Arg1 and YM1 gene expression, and HB-EGF production were further enhanced by inhibition of EGFR activity in Raw 264.7 cells using an EGFR kinase inhibitor and in peritoneal macrophages from Egfr(wa5) mice with kinase inactive EGFR and by knockdown of EGFR in peritoneal macrophages from Egfr(fl/fl) LysM-Cre mice with myeloid cell-specific EGFR deletion. Chitin induced a higher level of M2 polarization in peritoneal macrophages in Egfr(fl/fl) LysM-Cre mice than that in Egfr(fl/fl) mice. Accordingly, IL-4-conditioned medium stimulated growth and epithelial-to-mesenchymal transition in gastric epithelial and colonic tumor cells, which were suppressed by that from Raw 264.7 cells with HB-EGF knockdown but promoted by that from Egfr(wa5) and Egfr(fl/fl) LysM-Cre peritoneal macrophages. Clinical assessment revealed that the number of macrophages with EGFR expression became less, indicating decreased inhibitory effects on M2 polarization, in late stage of human gastric cancers. Thus, IL-4-stimulated HB-EGF-dependent transactivation of EGFR in macrophages may mediate inhibitory feedback for M2 polarization and HB-EGF production, thereby inhibiting gastrointestinal tumor growth.

  5. Presence of urokinase in serum-free primary rat hepatocyte cultures and its role in activating hepatocyte growth factor.

    PubMed

    Mars, W M; Kim, T H; Stolz, D B; Liu, M L; Michalopoulos, G K

    1996-06-15

    Serum-free rat hepatocyte cultures can be stimulated to divide by the inactive, single-chain form of hepatocyte growth factor (scHGF), suggesting that hepatocytes contain a protein that can cleave scHGF to its biologically active, two-chain (tcHGF) form. We added radiolabeled scHGF to serum-free cultures and confirmed that tcHGF was being generated. Because scHGF can be cleaved to tcHGF by plasminogen activators (PAs), we next tested the cultures for active PA. Although little PA activity was initially present, the majority was of the urokinase type (u-PA) as determined by neutralization studies using either a polyclonal antibody against u-PA or, since u-PA functions in the context of its receptor (u-PAR), a monoclonal antibody against u-PAR. Considerable PA activity developed within 24 h, which was also neutralizable with antibody. To test whether the active, receptor-bound u-PA from the cell cultures was cleaving scHGF, iodinated scHGF was added to intact cells in the presence of the antibody against u-PAR. Comparison to control cultures determined that the antibody prevented scHGF cleavage. Analysis of cultures treated with HGF, epidermal growth factor, and transforming growth factor alpha (TGF-alpha) alpha showed these growth factors increased the hepatocyte PA activity in parallel with the mRNA for u-PA. TGF-beta had the opposite effect, and when TGF-beta was added to the culture system, conversion of scHGF to tcHGF was prevented in concert with the production of the type 1 PA inhibitor. When liver remnants from hepatectomized animals were assayed for active TGF-beta, elevated protein was found just prior to the appearance of PA inhibitor 1 message and protein. Collectively, our data show that in culture, active u-PA is present and cleaves scHGF to tcHGF in the context of its receptor. It also suggests that modulation of u-PA activity by various growth factors is relevant for regulating cleavage of scHGF to tcHGF both in vitro and in vivo.

  6. Allicin inhibits lymphangiogenesis through suppressing activation of vascular endothelial growth factor (VEGF) receptor.

    PubMed

    Wang, Weicang; Du, Zheyuan; Nimiya, Yoshiki; Sukamtoh, Elvira; Kim, Daeyoung; Zhang, Guodong

    2016-03-01

    Allicin, the most abundant organosulfur compound in freshly crushed garlic tissues, has been shown to have various health-promoting effects, including anticancer actions. A better understanding of the effects and mechanisms of allicin on tumorigenesis could facilitate development of allicin or garlic products for cancer prevention. Here we found that allicin inhibited lymphangiogenesis, which is a critical cellular process implicated in tumor metastasis. In primary human lymphatic endothelial cells, allicin at 10 μM inhibited capillary-like tube formation and cell migration, and it suppressed phosphorylation of vascular endothelial growth factor receptor 2 and focal adhesion kinase. Using a Matrigel plug assay in mice, addition of 10 μg allicin in Matrigel plug inhibited 40-50% of vascular endothelial growth factor-C-induced infiltration of lymphatic endothelial cells and leukocytes. S-Allylmercaptoglutathione, a major cellular metabolite of allicin, had no effect on lymphangiogenic responses in lymphatic endothelial cells. Together, these results demonstrate the antilymphangiogenic effect of allicin in vitro and in vivo, suggesting a novel mechanism for the health-promoting effects of garlic compounds. PMID:26895668

  7. Implications of Insulin-like Growth Factor 1 Receptor Activation in Lung Cancer

    PubMed Central

    Nurwidya, Fariz; Andarini, Sita; Takahashi, Fumiyuki; Syahruddin, Elisna; Takahashi, Kazuhisa

    2016-01-01

    Insulin-like growth factor 1 receptor (IGF1R) has been intensively investigated in many preclinical studies using cell lines and animal models, and the results have provided important knowledge to help improve the understanding of cancer biology. IGF1R is highly expressed in patients with lung cancer, and high levels of circulating insulin-like growth factor 1 (IGF1), the main ligand for IGF1R, increases the risk of developing lung malignancy in the future. Several phase I clinical trials have supported the potential use of an IGF1R-targeted strategy for cancer, including lung cancer. However, the negative results from phase III studies need further attention, especially in selecting patients with specific molecular signatures, who will gain benefits from IGF1R inhibitors with minimal side effects. This review will discuss the basic concept of IGF1R in lung cancer biology, such as epithelial-mesenchymal transition (EMT) induction and cancer stem cell (CSC) maintenance, and also the clinical implications of IGF1R for lung cancer patients, such as prognostic value and cancer therapy resistance. PMID:27418865

  8. Nuclear factor kappaB/p49 is a negative regulatory factor in nerve growth factor-induced choline acetyltransferase promoter activity in PC12 cells.

    PubMed

    Toliver-Kinsky, T; Wood, T; Perez-Polo, J R

    2000-12-01

    Anovel nuclear factor kappaB (NF-kappaB) binding site has been identified within the promoter region of the mouse gene encoding choline acetyltransferase (ChAT), the enzyme that synthesizes acetylcholine and has been implicated in the cognitive deficits associated with aging and Alzheimer's disease. This binding site, which is located within the nerve growth factor (NGF)-responsive enhancer element, was recognized by the NF-kappaB protein p49 but not p65 or p50. p49 from both basal forebrain and PC12 nuclear extracts interacted with this specific sequence in electrophoretic mobility shift assays. Mutation of the NF-kappaB site caused an increase in NGF-induced promoter activation, whereas overexpression of p49 in NGF-differentiated PC12 cells caused a decrease in endogenous ChAT enzyme activity and a decrease in promoter activity that was specifically mediated through this NF-kappaB binding site. Treatment of PC12 cells with NGF resulted in a drastic reduction in nuclear p49 binding to the ChAT NF-kappaB site after 24 h, but nuclear p49 levels were not altered, suggesting that late NGF-mediated events prevent binding of p49 to the ChAT promoter by an unknown mechanism other than nuclear translocation. Decreased ChAT expression and increased NF-kappaB activity in the brain are associated with aging and Alzheimer's disease. These data indicate that p49 is a negative regulator of ChAT expression and suggest a possible mechanism for aging-associated declines in cholinergic function.

  9. Factors Limiting Microbial Growth and Activity at a Proposed High-Level Nuclear Repository, Yucca Mountain, Nevada

    PubMed Central

    Kieft, T. L.; Kovacik, W. P.; Ringelberg, D. B.; White, D. C.; Haldeman, D. L.; Amy, P. S.; Hersman, L. E.

    1997-01-01

    As part of the characterization of Yucca Mountain, Nev., as a potential repository for high-level nuclear waste, volcanic tuff was analyzed for microbial abundance and activity. Tuff was collected aseptically from nine sites along a tunnel in Yucca Mountain. Microbial abundance was generally low: direct microscopic cell counts were near detection limits at all sites (3.2 x 10(sup4) to 2.0 x 10(sup5) cells g(sup-1) [dry weight]); plate counts of aerobic heterotrophs ranged from 1.0 x 10(sup1) to 3.2 x 10(sup3) CFU g(sup-1) (dry weight). Phospholipid fatty acid concentrations (0.1 to 3.7 pmol g(sup-1)) also indicated low microbial biomasses; diglyceride fatty acid concentrations, indicative of dead cells, were in a similar range (0.2 to 2.3 pmol g(sup-1)). Potential microbial activity was quantified as (sup14)CO(inf2) production in microcosms containing radiolabeled substrates (glucose, acetate, and glutamic acid); amendments with water and nutrient solutions (N and P) were used to test factors potentially limiting this activity. Similarly, the potential for microbial growth and the factors limiting growth were determined by performing plate counts before and after incubating volcanic tuff samples for 24 h under various conditions: ambient moisture, water-amended, and amended with various nutrient solutions (N, P, and organic C). A high potential for microbial activity was demonstrated by high rates of substrate mineralization (as much as 70% of added organic C in 3 weeks). Water was the major limiting factor to growth and microbial activity, while amendments with N and P resulted in little further stimulation. Organic C amendments stimulated growth more than water alone. PMID:16535670

  10. A novel transcriptional factor with Ser/Thr kinase activity involved in the transforming growth factor (TGF)-beta signalling pathway.

    PubMed Central

    Ohta, S; Takeuchi, M; Deguchi, M; Tsuji, T; Gahara, Y; Nagata, K

    2000-01-01

    Transforming growth factor-beta (TGF-beta) shows a variety of biological activities in various organs or cells. Recently some factors such as Smads (Sma and Mad proteins) and TGF-beta activating kinase 1 ('TAK1') have been characterized as signalling molecules downstream of TGF-beta. Several TGF-beta response elements have been identified such as cAMP response element, Smad binding element, and recognition sites for activating protein-1 and stimulating protein-1 in various gene promoters. We also reported a TGF-beta response element in the human C-type natriuretic peptide (CNP) gene promoter. In this paper, we report on a novel factor which regulates the TGF-beta response promoter. This factor, named TSF1 (TGF-beta stimulated factor 1), possessed DNA-binding ability and activated the TGF-beta responsive CNP promoter or vascular endothelial growth factor gene promoter which possesses a sequence element analogous to the TGF-beta responsive GC-rich element of the CNP promoter. TSF1 did not directly activate a Smads-dependent promoter from plasminogen activator inhibitor 1 gene, but it showed enhancement in co-operation with Smad3 and Smad4. Interestingly, this factor had the structural features of a Ser/Thr kinase and actually exhibited protein kinase activity. TSF1 mRNA as well as its protein level were stimulated by TGF-beta treatment. Thus, TSF1 is an unique factor with two biological functions, transcriptional regulation and protein phosphorylation, that may be involved in TGF-beta signals. PMID:10947953

  11. Cytokine and Growth Factor Activation In Vivo and In Vitro after Spinal Cord Injury.

    PubMed

    Garcia, Elisa; Aguilar-Cevallos, Jorge; Silva-Garcia, Raul; Ibarra, Antonio

    2016-01-01

    Spinal cord injury results in a life-disrupting series of deleterious interconnected mechanisms encompassed by the primary and secondary injury. These events are mediated by the upregulation of genes with roles in inflammation, transcription, and signaling proteins. In particular, cytokines and growth factors are signaling proteins that have important roles in the pathophysiology of SCI. The balance between the proinflammatory and anti-inflammatory effects of these molecules plays a critical role in the progression and outcome of the lesion. The excessive inflammatory Th1 and Th17 phenotypes observed after SCI tilt the scale towards a proinflammatory environment, which exacerbates the deleterious mechanisms present after the injury. These mechanisms include the disruption of the spinal cord blood barrier, edema and ion imbalance, in particular intracellular calcium and sodium concentrations, glutamate excitotoxicity, free radicals, and the inflammatory response contributing to the neurodegenerative process which is characterized by demyelination and apoptosis of neuronal tissue. PMID:27418745

  12. Gefitinib in the treatment of nonsmall cell lung cancer with activating epidermal growth factor receptor mutation

    PubMed Central

    Nurwidya, Fariz; Takahashi, Fumiyuki; Takahashi, Kazuhisa

    2016-01-01

    Lung cancer is still the main cause of cancer-related deaths worldwide, with most patients present with advanced disease and poor long-term prognosis. The aim of lung cancer treatment is to slow down the progression of the disease, to relieve the patients from the lung cancer symptoms and whenever possible, to increase the overall survival. The discovery of small molecule targeting tyrosine kinase of epidermal growth factor receptor opens a new way in the management of advanced nonsmall cell lung cancer (NSCLC). This review will discuss several Phase II and III trials evaluated the clinical efficacy of gefitinib as monotherapy in pretreated patients with advanced NSCLC, as well as both monotherapy and combined with chemotherapy in chemotherapy-naive patients. PMID:27433059

  13. Cytokine and Growth Factor Activation In Vivo and In Vitro after Spinal Cord Injury

    PubMed Central

    Aguilar-Cevallos, Jorge; Silva-Garcia, Raul; Ibarra, Antonio

    2016-01-01

    Spinal cord injury results in a life-disrupting series of deleterious interconnected mechanisms encompassed by the primary and secondary injury. These events are mediated by the upregulation of genes with roles in inflammation, transcription, and signaling proteins. In particular, cytokines and growth factors are signaling proteins that have important roles in the pathophysiology of SCI. The balance between the proinflammatory and anti-inflammatory effects of these molecules plays a critical role in the progression and outcome of the lesion. The excessive inflammatory Th1 and Th17 phenotypes observed after SCI tilt the scale towards a proinflammatory environment, which exacerbates the deleterious mechanisms present after the injury. These mechanisms include the disruption of the spinal cord blood barrier, edema and ion imbalance, in particular intracellular calcium and sodium concentrations, glutamate excitotoxicity, free radicals, and the inflammatory response contributing to the neurodegenerative process which is characterized by demyelination and apoptosis of neuronal tissue. PMID:27418745

  14. Directed random walks and constraint programming reveal active pathways in hepatocyte growth factor signaling.

    PubMed

    Kittas, Aristotelis; Delobelle, Aurélien; Schmitt, Sabrina; Breuhahn, Kai; Guziolowski, Carito; Grabe, Niels

    2016-01-01

    An effective means to analyze mRNA expression data is to take advantage of established knowledge from pathway databases, using methods such as pathway-enrichment analyses. However, pathway databases are not case-specific and expression data could be used to infer gene-regulation patterns in the context of specific pathways. In addition, canonical pathways may not always describe the signaling mechanisms properly, because interactions can frequently occur between genes in different pathways. Relatively few methods have been proposed to date for generating and analyzing such networks, preserving the causality between gene interactions and reasoning over the qualitative logic of regulatory effects. We present an algorithm (MCWalk) integrated with a logic programming approach, to discover subgraphs in large-scale signaling networks by random walks in a fully automated pipeline. As an exemplary application, we uncover the signal transduction mechanisms in a gene interaction network describing hepatocyte growth factor-stimulated cell migration and proliferation from gene-expression measured with microarray and RT-qPCR using in-house perturbation experiments in a keratinocyte-fibroblast co-culture. The resulting subgraphs illustrate possible associations of hepatocyte growth factor receptor c-Met nodes, differentially expressed genes and cellular states. Using perturbation experiments and Answer Set programming, we are able to select those which are more consistent with the experimental data. We discover key regulator nodes by measuring the frequency with which they are traversed when connecting signaling between receptors and significantly regulated genes and predict their expression-shift consistently with the measured data. The Java implementation of MCWalk is publicly available under the MIT license at: https://bitbucket.org/akittas/biosubg.

  15. AZD-4547 exerts potent cytostatic and cytotoxic activities against fibroblast growth factor receptor (FGFR)-expressing colorectal cancer cells.

    PubMed

    Yao, Ting-Jing; Zhu, Jin-Hai; Peng, De-Feng; Cui, Zhen; Zhang, Chao; Lu, Pei-hua

    2015-07-01

    Colorectal cancer (CRC) causes significant mortalities worldwide. Fibroblast growth factor (FGF) receptor (FGFR) signaling is frequently dysregulated and/or constitutively activated in CRCs, contributing to cancer carcinogenesis and progression. Here, we studied the activity of AZD-4547, a novel and potent FGFR kinase inhibitor, on CRC cells. AZD-4547 inhibited CRC cell growth in vitro, and its activity correlated with the FGFR-1/2 expression level. AZD-4547 was cytotoxic and pro-apoptotic in FGFR-1/2-expressed CRC cell lines (NCI-H716 and HCT-116), but not in FGFR-1/2 null HT-29 cells. Further, AZD-4547 inhibited cell cycle progression and attenuated the activation of FGFR1-FGFR substrate 2 (FRS-2), ERK/mitogen-activated protein kinase (MAPK), and AKT/mammalian target of rapamycin (AKT/mTOR) signalings in NCI-H716 and HCT-116 cells. In vivo, AZD-4547 oral administration at effective doses inhibited NCI-H716 (high FGFR-1/2 expression) xenograft growth in nude mice. Phosphorylation of FGFR-1, AKT, and ERK1/2 in xenograft specimens was also inhibited by AZD-4547 administration. Thus, our preclinical studies strongly support possible clinical investigations of AZD-4547 for the treatment of CRCs harboring deregulated FGFR signalings. PMID:25691251

  16. Midkine and pleiotrophin have bactericidal properties: preserved antibacterial activity in a family of heparin-binding growth factors during evolution.

    PubMed

    Svensson, Sara L; Pasupuleti, Mukesh; Walse, Björn; Malmsten, Martin; Mörgelin, Matthias; Sjögren, Camilla; Olin, Anders I; Collin, Mattias; Schmidtchen, Artur; Palmer, Ruth; Egesten, Arne

    2010-05-21

    Antibacterial peptides of the innate immune system combat pathogenic microbes, but often have additional roles in promoting inflammation and as growth factors during tissue repair. Midkine (MK) and pleiotrophin (PTN) are the only two members of a family of heparin-binding growth factors. They show restricted expression during embryogenesis and are up-regulated in neoplasia. In addition, MK shows constitutive and inflammation-dependent expression in some non-transformed tissues of the adult. In the present study, we show that both MK and PTN display strong antibacterial activity, present at physiological salt concentrations. Electron microscopy of bacteria and experiments using artificial lipid bilayers suggest that MK and PTN exert their antibacterial action via a membrane disruption mechanism. The predicted structure of PTN, employing the previously solved MK structure as a template, indicates that both molecules consist of two domains, each containing three antiparallel beta-sheets. The antibacterial activity was mapped to the unordered C-terminal tails of both molecules and the last beta-sheets of the N-terminals. Analysis of the highly conserved MK and PTN orthologues from the amphibian Xenopus laevis and the fish Danio rerio suggests that they also harbor antibacterial activity in the corresponding domains. In support of an evolutionary conserved function it was found that the more distant orthologue, insect Miple2 from Drosophila melanogaster, also displays strong antibacterial activity. Taken together, the findings suggest that MK and PTN, in addition to their earlier described activities, may have previously unrealized important roles as innate antibiotics.

  17. Design and biological activity of epidermal growth factor receptor-targeted peptide doxorubicin conjugate.

    PubMed

    Fan, Mingliang; Yang, Danbo; Liang, Xiaofei; Ao, Junping; Li, Zonghai; Wang, Hongyang; Shi, Bizhi

    2015-03-01

    The nonspecific toxicity of anticancer drug doxorubicin (DOX) toward both tumor and normal cells can result in serious side effects, thereby limiting its clinical applications. In this wok, epidermal growth factor receptor (EGFR) antagonist peptide GE11 was introduced into DOX structure via a disulfide bond which can be cleaved by reduced glutathione (GSH). We have investigated the intracellular delivery and in vitro cytotoxicity of GE11-DOX conjugate and free DOX in high (SMMC-7721) and low (MCF-7) EGFR expressing cancer cell models. GE11-DOX accumulated at higher levels in SMMC-7721 cells than in MCF-7 cells, while the cellular uptake of free DOX was almost the same in both cells. Furthermore, pretreating with anti-EGFR monoclonal antibody reduced intracellular accumulation of GE11-DOX in SMMC-7721, indicating the involvement of EGFR pathway in the transport of conjugate. Our results suggest that GE11-DOX conjugate has the potential to be a therapeutic agent for treating EGFR overexpressing tumor.

  18. Hepatocyte growth factor triggers distinct mechanisms of Asef and Tiam1 activation to induce endothelial barrier enhancement.

    PubMed

    Higginbotham, Katherine; Tian, Yufeng; Gawlak, Grzegorz; Moldobaeva, Nurgul; Shah, Alok; Birukova, Anna A

    2014-11-01

    Previous reports described an important role of hepatocyte growth factor (HGF) in mitigation of pulmonary endothelial barrier dysfunction and cell injury induced by pathologic agonists and mechanical forces. HGF protective effects have been associated with Rac-GTPase signaling pathway activated by Rac-specific guanine nucleotide exchange factor Tiam1 and leading to enhancement of intercellular adherens junctions. This study tested involvement of a novel Rac-specific activator, Asef, in endothelial barrier enhancement by HGF and investigated a mechanism of HGF-induced Asef activation. Si-RNA-based knockdown of Tiam1 and Asef had an additive effect on attenuation of HGF-induced Rac activation and endothelial cell (EC) barrier enhancement. Tiam1 and Asef activation was abolished by pharmacologic inhibitors of HGF receptor and PI3-kinase. In contrast to Tiam1, Asef interacted with APC and associated with microtubule fraction upon HGF stimulation. EC treatment by low dose nocodazole to inhibit peripheral microtubule dynamics partially attenuated HGF-induced Asef peripheral translocation, but had negligible effect on Tiam1 translocation. These effects were associated with attenuation of HGF-induced barrier enhancement in EC pretreated with low ND dose and activation of Rac and its cytoskeletal effectors PAK1 and cortactin. These data demonstrate, that in addition to microtubule-independent Tiam1 activation, HGF engages additional microtubule- and APC-dependent pathway of Asef activation. These mechanisms may complement each other to provide the fine tuning of Rac signaling and endothelial barrier enhancement in response to various agonists.

  19. Role of diacylglycerol-regulated protein kinase C isotypes in growth factor activation of the Raf-1 protein kinase.

    PubMed

    Cai, H; Smola, U; Wixler, V; Eisenmann-Tappe, I; Diaz-Meco, M T; Moscat, J; Rapp, U; Cooper, G M

    1997-02-01

    The Raf protein kinases function downstream of Ras guanine nucleotide-binding proteins to transduce intracellular signals from growth factor receptors. Interaction with Ras recruits Raf to the plasma membrane, but the subsequent mechanism of Raf activation has not been established. Previous studies implicated hydrolysis of phosphatidylcholine (PC) in Raf activation; therefore, we investigated the role of the epsilon isotype of protein kinase C (PKC), which is stimulated by PC-derived diacylglycerol, as a Raf activator. A dominant negative mutant of PKC epsilon inhibited both proliferation of NIH 3T3 cells and activation of Raf in COS cells. Conversely, overexpression of active PKC epsilon stimulated Raf kinase activity in COS cells and overcame the inhibitory effects of dominant negative Ras in NIH 3T3 cells. PKC epsilon also stimulated Raf kinase in baculovirus-infected Spodoptera frugiperda Sf9 cells and was able to directly activate Raf in vitro. Consistent with its previously reported activity as a Raf activator in vitro, PKC alpha functioned similarly to PKC epsilon in both NIH 3T3 and COS cell assays. In addition, constitutively active mutants of both PKC alpha and PKC epsilon overcame the inhibitory effects of dominant negative mutants of the other PKC isotype, indicating that these diacylglycerol-regulated PKCs function as redundant activators of Raf-1 in vivo.

  20. Activity-sensitive signaling by muscle-derived insulin-like growth factors in the developing and regenerating neuromuscular system.

    PubMed

    Caroni, P

    1993-08-27

    In the nervous system, activity-sensitive retrograde signaling pathways couple the status of postsynaptic activation to elimination of collaterals during development and collateral sprouting in the adult. This article presents evidence supporting the hypothesis that in the neuromuscular system, skeletal muscle fiber derived insulin-like growth factors play a central role in such signaling. This evidence includes (1) timing and activity-sensitive expression of IGFs in skeletal muscle fibers, (2) identification of an IGF- and activity-sensitive retrograde signaling pathway from developing muscle to motoneurons in the spinal cord, (3) demonstration that IGFs in the muscle are both sufficient and necessary to induce interstitial cell proliferation and intramuscular nerve sprouting in adult muscle.

  1. Prediction of Inhibitory Activity of Epidermal Growth Factor Receptor Inhibitors Using Grid Search-Projection Pursuit Regression Method

    PubMed Central

    Du, Hongying; Hu, Zhide; Bazzoli, Andrea; Zhang, Yang

    2011-01-01

    The epidermal growth factor receptor (EGFR) protein tyrosine kinase (PTK) is an important protein target for anti-tumor drug discovery. To identify potential EGFR inhibitors, we conducted a quantitative structure–activity relationship (QSAR) study on the inhibitory activity of a series of quinazoline derivatives against EGFR tyrosine kinase. Two 2D-QSAR models were developed based on the best multi-linear regression (BMLR) and grid-search assisted projection pursuit regression (GS-PPR) methods. The results demonstrate that the inhibitory activity of quinazoline derivatives is strongly correlated with their polarizability, activation energy, mass distribution, connectivity, and branching information. Although the present investigation focused on EGFR, the approach provides a general avenue in the structure-based drug development of different protein receptor inhibitors. PMID:21811593

  2. Epidermal growth factor induces biphasic activation of ornithine decarboxylase in human stomach-derived KATO-III cells.

    PubMed

    Ishikawa, T; Mitsuhashi, M; Ichikawa, Y; Tarnawski, A

    1994-01-01

    Effect of epidermal growth factor (EGF) on ornithine decarboxylase (ODC) was examined in human gastric cancer-derived KATO-III cells, because 125I-EGF binding studies indicated a presence of specific binding sites for EGF on these cells. Upon stimulation with EGF, both ODC mRNA expression and ODC enzyme activity were significantly increased in KATO-III cells. However, unlike in other cellular systems, both EGF-induced ODC mRNA expression and ODC enzyme activation were biphasic with the peaks at 15 +/- 10 min and 2.1 +/- 1.5 hrs (mean +/- SE) for mRNA, and 3.1 +/- 1.5 and 7.7 +/- 1.8 hrs (mean +/- SE) for enzyme activity, respectively. Therefore, KATO-III cell line may provide a unique model for the biochemical analysis of EGF action on ODC activation. PMID:8190004

  3. Activation of JNK signaling mediates connective tissue growth factor expression and scar formation in corneal wound healing.

    PubMed

    Shi, Long; Chang, Yuan; Yang, Yongmei; Zhang, Ying; Yu, Fu-Shin X; Wu, Xinyi

    2012-01-01

    Connective Tissue Growth Factor (CTGF) and Transforming growth factor-β1 (TGF-β1) are key growth factors in regulating corneal scarring. Although CTGF was induced by TGF-β1 and mediated many of fibroproliferative effects of TGF-β1, the signaling pathway for CTGF production in corneal scarring remains to be clarified. In the present study, we firstly investigated the effects of c-Jun N-terminal kinase (JNK) on CTGF expression induce by TGF-β1 in Telomerase-immortalized human cornea stroma fibroblasts (THSF). Then, we created penetrating corneal wound model and determined the effect of JNK in the pathogenesis of corneal scarring. TGF-β1 activated MAPK pathways in THSF cells. JNK inhibitor significantly inhibited CTGF, fibronectin and collagen I expression induced by TGF-β1 in THSF. In corneal wound healing, the JNK inhibitor significantly inhibited CTGF expression, markedly improved the architecture of corneal stroma and reduced corneal scar formation, but did not have a measurable impact on corneal wound healing in vivo. Our results indicate that JNK mediates the expression of CTGF and corneal scarring in corneal wound healing, and might be considered as specific targets of drug therapy for corneal scarring.

  4. Growth factors in orthopedic surgery

    PubMed Central

    Zaharia, C; Despa, N; Simionescu, M; Jinga, V; Fleseriu, I

    2010-01-01

    Growth factors have represented an essential issue of interest for the researchers and clinicians in orthopedics and trauma over the last 40 years. In the last 10 to 15 years, the advances registered in this field have permitted the identification of the most active cellular and humoral factors as well as the improvement of their use in the orthopedic and trauma surgery. Their domain of application has been continuously enlarged and the results have been visible from the beginning. The authors present their appreciation on the actual state of this subject as well as their experience with results and related conclusions. PMID:20302195

  5. Wounding Sheets of Epithelial Cells Activates the Epidermal Growth Factor Receptor through Distinct Short- and Long-Range Mechanisms

    PubMed Central

    Block, Ethan R.

    2008-01-01

    Wounding epithelia induces activation of the epidermal growth factor receptor (EGFR), which is absolutely required for induction of motility. ATP is released from cells after wounding; it binds to purinergic receptors on the cell surface, and the EGFR is subsequently activated. Exogenous ATP activates phospholipase D, and we show here that ATP activates the EGFR through the phospholipase D2 isoform. The EGFR is activated in cells far (>0.3 cm) from wounds, which is mediated by diffusion of extracellular ATP because activation at a distance from wounds is abrogated by eliminating ATP in the medium with apyrase. In sharp contrast, activation of the EGFR near wounds is not sensitive to apyrase. Time-lapse microscopy revealed that cells exhibit increased motilities near edges of wounds; this increase in motility is not sensitive to apyrase, and apyrase does not detectably inhibit healing of wounds in epithelial sheets. This novel ATP/PLD2-independent pathway activates the EGFR by a transactivation process through ligand release, and it involves signaling by a member of the Src family of kinases. We conclude that wounding activates two distinct signaling pathways that induce EGFR activation and promote healing of wounds in epithelial cells. One pathway signals at a distance from wounds through release of ATP, and another pathway acts locally and is independent on ATP signaling. PMID:18799627

  6. Osteostatin improves the osteogenic activity of fibroblast growth factor-2 immobilized in Si-doped hydroxyapatite in osteoblastic cells.

    PubMed

    Lozano, Daniel; Feito, María José; Portal-Núñez, Sergio; Lozano, Rosa María; Matesanz, María Concepción; Serrano, María Concepción; Vallet-Regí, María; Portolés, María Teresa; Esbrit, Pedro

    2012-07-01

    Si-doped hydroxyapatite (Si-HA) is a suitable ceramic for the controlled release of agents to improve bone repair. We recently showed that parathyroid hormone-related protein (PTHrP) (107-111) (osteostatin) has remarkable osteogenic features in various in vitro and in vivo systems. Fibroblast growth factor (FGF)-2 modulates osteoblastic function and induces angiogenesis, and can promote osteoblast adhesion and proliferation after immobilization on Si-HA. In the present study we examined whether osteostatin might improve the biological efficacy of FGF-2-coated Si-HA in osteoblastic MC3T3-E1 cells in vitro. We found that Si-HA/FGF-2 in the presence or absence of osteostatin (100 nM) similarly increased cell growth (by about 50%). However, addition of the latter peptide to Si-HA/FGF-2 significantly enhanced gene expression of Runx2, osteocalcin, vascular endothelial growth factor (VEGF) and the VEGF receptors 1 and 2, without significantly affecting that of FGF receptors in these cells. Moreover, secreted VEGF in the MC3T3-E1 cell conditioned medium, which induced the proliferation of pig endothelial-like cells, was also enhanced by these combined factors. The synergistic action of osteostatin and Si-HA/FGF-2 on the VEGF system was abrogated by a mitogen-activated protein kinase inhibitor (U0126) and by the calcium antagonist verapamil. This action was related to an enhancement of alkaline phosphatase activity and matrix mineralization in MC3T3-E1 cells, and also in primary human osteoblastic cells. These in vitro data show that osteostatin increases the osteogenic efficacy of a Si-HA/FGF-2 biomaterial by a mechanism involving mitogen-activated protein kinases and intracellular Ca(2+). These findings provide an attractive strategy for bone tissue engineering.

  7. Interleukin-8 increases vascular endothelial growth factor and neuropilin expression and stimulates ERK activation in human pancreatic cancer.

    PubMed

    Li, Min; Zhang, Yuqing; Feurino, Louis W; Wang, Hao; Fisher, William E; Brunicardi, F Charles; Chen, Changyi; Yao, Qizhi

    2008-04-01

    Interleukin-8 (IL-8) is associated with tumorigenesis by promoting angiogenesis and metastasis. Although up-regulation of IL-8 is indicated in many cancers, its function in pancreatic cancer has not been well characterized. In this study we examined the expression of IL-8 on pancreatic cancer cells and clinical tissue specimens, and investigated the effect of exogenous IL-8 on gene expression, and signaling in human pancreatic cancer cells. We found that pancreatic cancer cells expressed higher amount of IL-8 mRNA than normal human pancreatic ductal epithelium cells. IL-8 mRNA was also substantially overexpressed in 11 of 14 (79%) clinical pancreatic-adenocarcinoma samples compared with that in their surrounding normal tissues. Exogenous IL-8 up-regulated the expression of vascular endothelial growth factor(165), and neuropilin (NRP)-2 in BxPC-3 cells, one of human pancreatic cancer cell lines. IL-8 expression was inducible by hypoxia mimicking reagent cobalt chloride. In addition, IL-8 activated extracellular signal-regulated kinase (ERK)1/2 signaling pathway in BxPC-3 cells. Our studies suggest that IL-8 might be a malignant factor in human pancreatic cancer by induction of vascular endothelial growth factor and NRP-2 expression and ERK activation. Targeting IL-8 along with other antiangiogenesis therapy could be an effective treatment for this malignancy.

  8. Hepatocyte growth factor activator is a potential target proteinase for Kazal-type inhibitor in turkey (Meleagris gallopavo) seminal plasma.

    PubMed

    Słowińska, Mariola; Bukowska, Joanna; Hejmej, Anna; Bilińska, Barbara; Kozłowski, Krzysztof; Jankowski, Jan; Ciereszko, Andrzej

    2015-08-01

    A peculiar characteristic of turkey seminal plasma is the increased activity of serine proteinases. It is of interest if the single-domain Kazal-type inhibitor controls the activity of turkey seminal plasma proteinases. Pure preparations of the Kazal-type inhibitor and anti-Kazal-type inhibitor monospecific immunoglobulin Gs were used as ligands in affinity chromatography for proteinase isolation from turkey seminal plasma. Gene expression and the immunohistochemical detection of the single-domain Kazal-type inhibitor in the reproductive tract of turkey toms are described. The hepatocyte growth factor activator (HGFA) was identified in the binding fraction in affinity chromatography. Hepatocyte growth factor activator activity was inhibited by the Kazal-type inhibitor in a dose-dependent manner. This protease was a primary physiological target for the single-domain Kazal-type inhibitor. Numerous proteoforms of HGFA were present in turkey seminal plasma, and phosphorylation was the primary posttranslational modification of HGFA. In addition to HGFA, acrosin was a target proteinase for the single-domain Kazal-type inhibitor. In seminal plasma, acrosin was present only in complexes with the Kazal-type inhibitor and was not present as a free enzyme. The single-domain Kazal-type inhibitor was specific for the reproductive tract. The germ cell-specific expression of Kazal-type inhibitors in the testis indicated an important function in spermatogenesis; secretion by the epithelial cells of the epididymis and the ductus deferens indicated that the Kazal-type inhibitor was an important factor involved in the changes in sperm membranes during maturation and in the maintenance of the microenvironment in which sperm maturation occurred and sperm was stored. The role of HGFA in these processes remains to be established.

  9. Spatiotemporal Control of Vascular Endothelial Growth Factor Expression Using a Heat-Shock-Activated, Rapamycin-Dependent Gene Switch

    PubMed Central

    Martín-Saavedra, Francisco M.; Wilson, Christopher G.; Voellmy, Richard; Vilaboa, Nuria

    2013-01-01

    Abstract A major challenge in regenerative medicine is to develop methods for delivering growth and differentiation factors in specific spatial and temporal patterns, thereby mimicking the natural processes of development and tissue repair. Heat shock (HS)-inducible gene expression systems can respond to spatial information provided by localized heating, but are by themselves incapable of sustained expression. Conversely, gene switches activated by small molecules provide tight temporal control and sustained expression, but lack mechanisms for spatial targeting. Here we combine the advantages of HS and ligand-activated systems by developing a novel rapamycin-regulated, HS-inducible gene switch that provides spatial and temporal control and sustained expression of transgenes such as firefly luciferase and vascular endothelial growth factor (VEGF). This gene circuit exhibits very low background in the uninduced state and can be repeatedly activated up to 1 month. Furthermore, dual regulation of VEGF induction in vivo is shown to stimulate localized vascularization, thereby providing a route for temporal and spatial control of angiogenesis. PMID:23527589

  10. Transforming growth factor-alpha-induced transcriptional activation of the vascular permeability factor (VPF/VEGF) gene requires AP-2-dependent DNA binding and transactivation.

    PubMed Central

    Gille, J; Swerlick, R A; Caughman, S W

    1997-01-01

    The endothelial cell-specific mitogen vascular permeability factor/vascular endothelial growth factor (VPF/VEGF) represents a central regulator of cutaneous angiogenesis. Increased VPF/VEGF expression has recently been reported in psoriatic skin and healing wounds, both conditions in which transforming growth factor-alpha (TGF alpha) and its ligand, the epidermal growth factor receptor, are markedly up-regulated. Since TGF alpha strongly induces VPF/VEGF synthesis in keratinocytes, TGF alpha-mediated VPF/VEGF expression is likely to play a significant role in the initiation and maintenance of increased vascular hyperpermeability and hyperproliferation in skin biology. The objectives of the present studies were to determine the molecular mechanisms responsible for TGF alpha-induced transcriptional activation of the VPF/VEGF gene. We have identified a GC-rich TGF alpha-responsive region between -88 bp and -65 bp of the VPF/VEGF promoter that is necessary for constitutive and TGF alpha-inducible transcriptional activation. In electrophoretic mobility shift assays, this region binds Sp1-dependent protein complexes constitutively and an additional TGF alpha-inducible protein complex that is distinct from Sp1 protein. Both AP-2 and Egr-1 transcription factors were detected as components of the TGF alpha-inducible protein complex in supershift EMSA studies. In co-transfection studies, an AP-2 but not an Egr-1 expression vector activated VPF/VEGF transcription, thus indicating that AP-2 protein is functionally important in TGF alpha-induced VPF/VEGF gene expression. By clarifying regulatory mechanisms that are critical for angiogenic processes in the skin, these studies may form the basis for new therapeutic strategies to modulate VPF/VEGF expression in cutaneous inflammation and wound healing. PMID:9049304

  11. Plasminogen activator inhibitor 1--insulin-like growth factor binding protein 3 cascade regulates stress-induced senescence.

    PubMed

    Elzi, David J; Lai, Yanlai; Song, Meihua; Hakala, Kevin; Weintraub, Susan T; Shiio, Yuzuru

    2012-07-24

    Cellular senescence is widely believed to play a key role in tumor suppression, but the molecular pathways that regulate senescence are only incompletely understood. By using a secretome proteomics approach, we identified insulin-like growth factor binding protein 3 (IGFBP3) as a secreted mediator of breast cancer senescence upon chemotherapeutic drug treatment. The senescence-inducing activity of IGFBP3 is inhibited by tissue-type plasminogen activator-mediated proteolysis, which is counteracted by plasminogen activator inhibitor 1 (PAI-1), another secreted mediator of senescence. We demonstrate that IGFBP3 is a critical downstream target of PAI-1-induced senescence. These results suggest a role for an extracellular cascade of secreted proteins in the regulation of cellular senescence.

  12. Dexamethasone effects on creatine kinase activity and insulin-like growth factor receptors in cultured muscle cells

    NASA Technical Reports Server (NTRS)

    Whitson, Peggy A.; Stuart, Charles A.; Huls, M. H.; Sams, Clarence F.; Cintron, Nitza M.

    1989-01-01

    The effect of dexamethasone on the activity of creatine kinase (CK) and the insulin-like growth factor I (IGF-I) binding were investigated using skeletal- and cardiac-muscle-derived cultured cell lines (mouse, C2C12; rat, L6 and H9c2). It was found that, in skeletal muscle cells, dexamethasone treatment during differentiation of skeletal-muscle cells caused dose-dependent increases in CK activity and increases in the degree of myotube formation, whereas cardiac cells (H9c2) exhibited very low CK activity during culture or dexamethasone treatment. Results for IGF-I binding were similar in all three cell lines. The IGF-I binding to dexamethasone-treated cells (50 nM for 24 hr on the day prior to confluence) resulted in an increased number of available binding sites, with no effect on the binding affinities.

  13. Linking γ-aminobutyric acid A receptor to epidermal growth factor receptor pathways activation in human prostate cancer.

    PubMed

    Wu, Weijuan; Yang, Qing; Fung, Kar-Ming; Humphreys, Mitchell R; Brame, Lacy S; Cao, Amy; Fang, Yu-Ting; Shih, Pin-Tsen; Kropp, Bradley P; Lin, Hsueh-Kung

    2014-03-01

    Neuroendocrine (NE) differentiation has been attributed to the progression of castration-resistant prostate cancer (CRPC). Growth factor pathways including the epidermal growth factor receptor (EGFR) signaling have been implicated in the development of NE features and progression to a castration-resistant phenotype. However, upstream molecules that regulate the growth factor pathway remain largely unknown. Using androgen-insensitive bone metastasis PC-3 cells and androgen-sensitive lymph node metastasis LNCaP cells derived from human prostate cancer (PCa) patients, we demonstrated that γ-aminobutyric acid A receptor (GABA(A)R) ligand (GABA) and agonist (isoguvacine) stimulate cell proliferation, enhance EGF family members expression, and activate EGFR and a downstream signaling molecule, Src, in both PC-3 and LNCaP cells. Inclusion of a GABA(A)R antagonist, picrotoxin, or an EGFR tyrosine kinase inhibitor, Gefitinib (ZD1839 or Iressa), blocked isoguvacine and GABA-stimulated cell growth, trans-phospohorylation of EGFR, and tyrosyl phosphorylation of Src in both PCa cell lines. Spatial distributions of GABAAR α₁ and phosphorylated Src (Tyr416) were studied in human prostate tissues by immunohistochemistry. In contrast to extremely low or absence of GABA(A)R α₁-positive immunoreactivity in normal prostate epithelium, elevated GABA(A)R α₁ immunoreactivity was detected in prostate carcinomatous glands. Similarly, immunoreactivity of phospho-Src (Tyr416) was specifically localized and limited to the nucleoli of all invasive prostate carcinoma cells, but negative in normal tissues. Strong GABAAR α₁ immunoreactivity was spatially adjacent to the neoplastic glands where strong phospho-Src (Tyr416)-positive immunoreactivity was demonstrated, but not in adjacent to normal glands. These results suggest that the GABA signaling is linked to the EGFR pathway and may work through autocrine or paracine mechanism to promote CRPC progression.

  14. 37 years of scientific activity in a Biochemistry Department in Brazil: patterns of growth and factors leading to increased productivity.

    PubMed

    Gomes, Urubatã E; Oliveira, Diogo L de; Berti, Luciana C; Amaral, Olavo; Souza, Diogo O; Wofchuk, Susana T

    2011-09-01

    Scientific activity in Brazil has experienced an accelerated growth in the past decades, with an increase in productivity that greatly surpasses the international average. This growth has occurred mostly at the expense of centers of excellence in public universities, which account for the vast majority of the country's scientific output. The aim of this study was to evaluate the production of the Department of Biochemistry of a large public university in southern Brazil (Universidade Federal do Rio Grande do Sul), as well as to identify internal and external policies that have influenced this growing production profile. We have performed a historical analysis of the scientific output of this Department of Biochemistry, which accounts for a considerable share of the indexed scientific production at this university. By focusing on the temporal course of its growth and drawing correlations between scientific output and important events in the history of the Department of Biochemistry and of the Brazilian science policies, we concluded that internal factors (as the creation of a postgraduation program, collaboration among researchers, experienced abroad researchers, qualification of faculty members) and external factors (as investments in the postgraduate education, the establishment of national scientific policies, such as financial stimuli for productive researchers and evaluation systems) influence scientific productivity in Brazil.

  15. Structural basis for activation of trimeric Gi proteins by multiple growth factor receptors via GIV/Girdin

    PubMed Central

    Lin, Changsheng; Ear, Jason; Midde, Krishna; Lopez-Sanchez, Inmaculada; Aznar, Nicolas; Garcia-Marcos, Mikel; Kufareva, Irina; Abagyan, Ruben; Ghosh, Pradipta

    2014-01-01

    A long-standing issue in the field of signal transduction is to understand the cross-talk between receptor tyrosine kinases (RTKs) and heterotrimeric G proteins, two major and distinct signaling hubs that control eukaryotic cell behavior. Although stimulation of many RTKs leads to activation of trimeric G proteins, the molecular mechanisms behind this phenomenon remain elusive. We discovered a unifying mechanism that allows GIV/Girdin, a bona fide metastasis-related protein and a guanine-nucleotide exchange factor (GEF) for Gαi, to serve as a direct platform for multiple RTKs to activate Gαi proteins. Using a combination of homology modeling, protein–protein interaction, and kinase assays, we demonstrate that a stretch of ∼110 amino acids within GIV C-terminus displays structural plasticity that allows folding into a SH2-like domain in the presence of phosphotyrosine ligands. Using protein–protein interaction assays, we demonstrated that both SH2 and GEF domains of GIV are required for the formation of a ligand-activated ternary complex between GIV, Gαi, and growth factor receptors and for activation of Gαi after growth factor stimulation. Expression of a SH2-deficient GIV mutant (Arg 1745→Leu) that cannot bind RTKs impaired all previously demonstrated functions of GIV—Akt enhancement, actin remodeling, and cell migration. The mechanistic and structural insights gained here shed light on the long-standing questions surrounding RTK/G protein cross-talk, set a novel paradigm, and characterize a unique pharmacological target for uncoupling GIV-dependent signaling downstream of multiple oncogenic RTKs. PMID:25187647

  16. A novel cysteine-rich neurotrophic factor in Aplysia facilitates growth, MAPK activation, and long-term synaptic facilitation.

    PubMed

    Pu, Lu; Kopec, Ashley M; Boyle, Heather D; Carew, Thomas J

    2014-04-01

    Neurotrophins are critically involved in developmental processes such as neuronal cell survival, growth, and differentiation, as well as in adult synaptic plasticity contributing to learning and memory. Our previous studies examining neurotrophins and memory formation in Aplysia showed that a TrkB ligand is required for MAPK activation, long-term synaptic facilitation (LTF), and long-term memory (LTM) for sensitization. These studies indicate that neurotrophin-like molecules in Aplysia can act as key elements in a functionally conserved TrkB signaling pathway. Here we report that we have cloned and characterized a novel neurotrophic factor, Aplysia cysteine-rich neurotrophic factor (apCRNF), which shares classical structural and functional characteristics with mammalian neurotrophins. We show that apCRNF (1) is highly enriched in the CNS, (2) enhances neurite elongation and branching, (3) interacts with mammalian TrkB and p75(NTR), (4) is released from Aplysia CNS in an activity-dependent fashion, (5) facilitates MAPK activation in a tyrosine kinase dependent manner in response to sensitizing stimuli, and (6) facilitates the induction of LTF. These results show that apCRNF is a native neurotrophic factor in Aplysia that can engage the molecular and synaptic mechanisms underlying memory formation.

  17. FRAG1, a gene that potently activates fibroblast growth factor receptor by C-terminal fusion through chromosomal rearrangement.

    PubMed Central

    Lorenzi, M V; Horii, Y; Yamanaka, R; Sakaguchi, K; Miki, T

    1996-01-01

    A constitutively active form of fibroblast growth factor 2 (FGFR2) was identified in rat osteosarcoma (ROS) cells by an expression cloning strategy. Unlike other tyrosine kinase receptors activated by N-terminal truncation in tumors, this receptor, FGFR2-ROS, contains an altered C terminus generated from chromosomal rearrangement with a novel gene, designated FGFR activating gene 1 (FRAG1). While the removal of the C terminus slightly activates FGFR2, the presence of the FRAG1 sequence drastically stimulates the transforming activity and autophosphorylation of the receptor. FGFR2-ROS is expressed as a unusually large protein and is highly phosphorylated in NIH 3T3 transfectants. FRAG1 is ubiquitously expressed and encodes a predicted protein of 28 kDa lacking significant structural similarity to known proteins. Epitope-tagged FRAG1 protein showed a perinuclear localization by immunofluorescence staining. The highly activated state of FGFR2-ROS appears to be attributed to constitutive dimer formation and higher phosphorylation level as well as possibly altered subcellular localization. These results indicate a unique mechanism of receptor activation by a C terminus alteration through a chromosomal fusion with FRAG1. Images Fig. 1 Fig. 2 Fig. 3 Fig. 5 Fig. 6 PMID:8799135

  18. Epidermal growth factor activates telomerase activity by direct binding of Ets-2 to hTERT promoter in lung cancer cells.

    PubMed

    Hsu, Chung-Ping; Lee, Li-Wen; Tang, Sheau-Chung; Hsin, I-Lun; Lin, Yu-Wen; Ko, Jiunn-Liang

    2015-07-01

    Growth signals are directly or indirectly involved in telomerase regulation. In this study, we investigated molecular mechanisms of the effect of EGF (epidermal growth factor) on regulating hTERT (human telomerase reverse transcriptase) expression. To elucidate specific transcription factors involved in EGF-stimulated hTERT transcription in A549 and H1299 lung cancer cells, transcription factors drives hTERT promoter activity, such as Myc, Mad, and Ets-2, was evaluated on luciferase reporter assay. The upregulation of hTERT promoter by Ets-2 and Myc were abolished by Mad. Using DAPA (DNA affinity precipitation assay), Ets-2 binding to SNP (T) was stronger than Ets-2 binding to SNP (C) at -245 bp upstream of the transcription start site within the core promoter of hTERT. Ets-2 silence by siRNA decreased hTERT expression at mRNA and protein levels. The regulation of hTERT promoter by EGF/Ets-2 was diminished via the EGFR kinase signal pathway-specific inhibitors AG1478 and Iressa. Inhibitors of Erk and Akt inhibited Ets-2-activated hTERT promoter activity. These data suggested that Ets-2, a genuine cancer-specific transcription factor, is actively involved in EGFR kinase-induced hTERT overexpression pathway in lung cancer cells. Blockage of this pathway may contribute to targeted gene therapy in lung cancer.

  19. Heparanase Plays a Dual Role in Driving Hepatocyte Growth Factor (HGF) Signaling by Enhancing HGF Expression and Activity*♦

    PubMed Central

    Ramani, Vishnu C.; Yang, Yang; Ren, Yongsheng; Nan, Li; Sanderson, Ralph D.

    2011-01-01

    Hepatocyte growth factor (HGF) is a heparin-binding cytokine that enhances growth, motility, and angiogenesis of many tumor types, including multiple myeloma where it is often highly expressed. However, little is known regarding what controls HGF level and activity in these tumors. Evaluation of bone marrow biopsies from myeloma patients revealed a strong positive correlation between the levels of HGF and heparanase, an endoglucuronidase known to promote aggressive tumor behavior. In vitro, addition of recombinant heparanase to myeloma cells or transfection of myeloma cell lines with the cDNA for heparanase significantly increased tumor cell expression and secretion of biologically active HGF. Shed syndecan-1, whose levels in myeloma are also enhanced by heparanase expression, binds to secreted HGF. This syndecan-1-HGF complex is active as shown by its ability to stimulate paracrine signaling via c-Met, the cell surface receptor for HGF. Surprisingly, heparanase enzyme activity was not required for up-regulation of HGF expression by the tumor cells. This is in contrast to the heparanase-mediated enhanced syndecan-1 shedding, which does require activity of the enzyme. This suggests that two different functional domains within the heparanase enzyme (the enzyme active site and a separate site) contribute to events leading to enhanced HGF signaling. These findings demonstrate a novel mechanism driving the HGF pathway whereby heparanase stimulates an increase in both HGF expression and syndecan-1 shedding to enhance HGF signaling. This work also provides further mechanistic insight into the dynamic role of heparanase in driving aggressive tumor progression. PMID:21131364

  20. PLATELET-DERIVED GROWTH FACTOR-C (PDGF-C) ACTIVATION BY SERINE PROTEASES: IMPLICATIONS FOR BREAST CANCER PROGRESSION

    PubMed Central

    Hurst, Newton J.; Najy, Abdo J.; Ustach, Carolyn V.; Movilla, Lisa; Kim, Hyeong-Reh Choi

    2012-01-01

    The PDGF family members are potent mitogens for cells of mesenchymal origin and serve as important regulators of cell migration, survival, apoptosis, and transformation. Tumor-derived PDGF ligands are thought to function in both autocrine and paracrine manners, activating receptors on tumor and surrounding stromal cells. PDGF-C and -D are secreted as latent dimers, unlike PDGF-A and -B. Cleavage of the CUB domain from the PDGF-C and -D dimers is required for their biological activity. At present, little is known about the proteolytic processing of PDGF-C, the rate-limiting step in the regulation of PDGF-C activity. Here we show that the breast carcinoma cell line, MCF7, engineered to overexpress PDGF-C, produces proteases capable of cleaving PDGF-C to its active form. Increased PDGF-C expression enhances cell proliferation, anchorage independent cell growth, and tumor cell motility by autocrine signaling. In addition, MCF7-produced PDGF-C induces fibroblast cell migration in a paracrine manner. Interestingly, PDGF-C enhances tumor cell invasion in the presence of fibroblast, suggesting a role of tumor-derived PDGF-C in tumor-stromal interactions. In the present study, we identify tissue plasminogen activator (tPA) and matriptase as major proteases for processing of PDGF-C in MCF7 cells. In in vitro studies, we also show that urokinase plasminogen activator (uPA) is able to process PDGF-C. Furthermore, by site-directed mutagenesis, we identify the cleavage site for these proteases in PDGF-C. Lastly, we provide evidence suggesting a 2-step proteolytic processing of PDGF-C involving creation of a hemidimer, followed by growth factor domain dimer (GFD-D) generation. PMID:22035541

  1. Transforming growth factor-beta activation in irradiated murine mammary gland.

    PubMed Central

    Barcellos-Hoff, M H; Derynck, R; Tsang, M L; Weatherbee, J A

    1994-01-01

    The biological activity of TGF-beta, an important modulator of cell proliferation and extracellular matrix formation, is governed by dissociation of mature TGF-beta from an inactive, latent TGF-beta complex in a process that is critical to its role in vivo. So far, it has not been possible to monitor activation in vivo since conventional immunohistochemical detection does not accurately discriminate latent versus active TGF-beta, nor have events associated with activation been defined well enough to serve as in situ markers of this process. We describe here a modified immunodetection method using differential antibody staining that allows the specific detection of active versus latent TGF-beta. Under these conditions, we report that an antibody raised to latency-associated peptide detects latent TGF-beta, and we demonstrate that LC(1-30) antibodies specifically recognize active TGF-beta 1 in tumor xenografts overproducing active TGF-beta 1, without cross-reactivity in tumors expressing similar levels of latent TGF-beta 1. We previously reported that TGF-beta immunoreactivity increases in murine mammary gland after whole-body 60Co-gamma radiation exposure. Using differential antibody staining we now show that radiation exposure specifically generates active TGF-beta 1. While latent TGF-beta 1 was widely distributed in unirradiated tissue, active TGF-beta 1 distribution was restricted. Active TGF-beta 1 increased significantly within 1 h of irradiation concomitant with decreased latent TGF-beta immunoreactivity. This rapid shift in immunoreactivity provides the first evidence for activation of TGF-beta in situ. This reciprocal pattern of expression persisted for 3 d and was accompanied by decreased recovery of latent TGF-beta 1 from irradiated tissue. Radiation-induced activation of TGF-beta may have profound implications for understanding tissue effects caused by radiation therapy. Images PMID:8113421

  2. High glucose increases Cdk5 activity in podocytes via transforming growth factor-β1 signaling pathway

    SciTech Connect

    Zhang, Yue; Li, Hongbo; Hao, Jun; Zhou, Yi; Liu, Wei

    2014-08-15

    Podocytes are highly specialized and terminally differentiated glomerular cells that play a vital role in the development and progression of diabetic nephropathy (DN). Cyclin-dependent kinase 5 (Cdk5), who is an atypical but essential member of the Cdk family of proline-directed serine/threonine kinases, has been shown as a key regulator of podocyte differentiation, proliferation and morphology. Our previous studies demonstrated that the expression of Cdk5 was significantly increased in podocytes of diabetic rats, and was closely related with podocyte injury of DN. However, the mechanisms of how expression and activity of Cdk5 are regulated under the high glucose environment have not yet been fully elucidated. In this study, we showed that high glucose up-regulated the expression of Cdk5 and its co-activator p35 with a concomitant increase in Cdk5 kinase activity in conditionally immortalized mouse podocytes in vitro. When exposed to 30 mM glucose, transforming growth factor-β1 (TGF-β1) was activated. Most importantly, we found that SB431542, the Tgfbr1 inhibitor, significantly decreased the expression of Cdk5 and p35 and Cdk5 kinase activity in high glucose-treated podocytes. Moreover, high glucose increased the expression of early growth response-1 (Egr-1) via TGF-β1-ERK1/2 pathway in podocytes and inhibition of Egr-1 by siRNA decreased p35 expression and Cdk5 kinase activity. Furthermore, inhibition of Cdk5 kinase activity effectively alleviated podocyte apoptosis induced by high glucose or TGF-β1. Thus, the TGF-β1-ERK1/2-Egr-1 signaling pathway may regulate the p35 expression and Cdk5 kinase activity in high glucose-treated podocytes, which contributes to podocyte injury of DN. - Highlights: • HG up-regulated the expression of Cdk5 and p35, and Cdk5 activity in podocytes. • HG activated TGF-β1 pathway and SB431542 inhibited Cdk5 expression and activity. • HG increased the expression of Egr-1 via TGF-β1-ERK1/2 pathway. • Inhibition of Egr-1

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

    SciTech Connect

    Tal, Tamara L.; Bromberg, Philip A.; Kim, Yumee; Samet, James M.

    2008-12-15

    Exposure to particulate matter (PM) is associated with increased cardiopulmonary morbidity and mortality. Diesel exhaust particles (DEP) are a major component of ambient PM and may contribute to PM-induced pulmonary inflammation. Proinflammatory signaling is mediated by phosphorylation-dependent signaling pathways whose activation is opposed by the activity of protein tyrosine phosphatases (PTPases) which thereby function to maintain signaling quiescence. PTPases contain an invariant catalytic cysteine that is susceptible to electrophilic attack. DEP contain electrophilic oxy-organic compounds that may contribute to the oxidant effects of PM. Therefore, we hypothesized that exposure to DEP impairs PTPase activity allowing for unopposed basal kinase activity. Here we report that exposure to 30 {mu}g/cm{sup 2} DEP for 4 h induces differential activation of signaling in primary cultures of human airway epithelial cells (HAEC), a primary target cell in PM inhalation. In-gel kinase activity assay of HAEC exposed to DEPs of low (L-DEP), intermediate (I-DEP) or high (H-DEP) organic content showed differential activation of intracellular kinases. Exposure to these DEP also induced varying levels of phosphorylation of the receptor tyrosine kinase EGFR in a manner that requires EGFR kinase activity but does not involve receptor dimerization. We demonstrate that treatment with DEP results in an impairment of total and EGFR-directed PTPase activity in HAEC with a potency that is independent of the organic content of these particles. These data show that DEP-induced EGFR phosphorylation in HAEC is the result of a loss of PTPase activities which normally function to dephosphorylate EGFR in opposition to baseline EGFR kinase activity.

  4. Neuroprotective Activity of Peripherally Administered Liver Growth Factor in a Rat Model of Parkinson’s Disease

    PubMed Central

    Gonzalo-Gobernado, Rafael; Calatrava-Ferreras, Lucía; Reimers, Diana; Herranz, Antonio Sánchez; Rodríguez-Serrano, Macarena; Miranda, Cristina; Jiménez-Escrig, Adriano; Díaz-Gil, Juan José; Bazán, Eulalia

    2013-01-01

    Liver growth factor (LGF) is a hepatic mitogen purified some years ago that promotes proliferation of different cell types and the regeneration of damaged tissues, including brain tissue. Considering the possibility that LGF could be used as a therapeutic agent in Parkinson’s disease, we analyzed its potential neuroregenerative and/or neuroprotective activity when peripherally administered to unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rats. For these studies, rats subjected to nigrostriatal lesions were treated intraperitoneally twice a week with LGF (5 microg/rat) for 3 weeks. Animals were sacrificed 4 weeks after the last LGF treatment. The results show that LGF stimulates sprouting of tyrosine hydroxylase-positive terminals and increases tyrosine hydroxylase and dopamine transporter expression, as well as dopamine levels in the denervated striatum of 6-OHDA-lesioned rats. In this structure, LGF activates microglia and raises tumor necrosis factor-alpha protein levels, which have been reported to have a role in neuroregeneration and neuroprotection. Besides, LGF stimulates the phosphorylation of MAPK/ERK1/2 and CREB, and regulates the expression of proteins which are critical for cell survival such as Bcl2 and Akt. Because LGF partially protects dopamine neurons from 6-OHDA neurotoxicity in the substantia nigra, and reduces motor deficits in these animals, we propose LGF as a novel factor that may be useful in the treatment of Parkinson’s disease. PMID:23861803

  5. Pathological Signaling via Platelet-Derived Growth Factor Receptor α Involves Chronic Activation of Akt and Suppression of p53 ▿

    PubMed Central

    Lei, Hetian; Velez, Gisela; Kazlauskas, Andrius

    2011-01-01

    In contrast to direct activation of platelet-derived growth factor (PDGF) receptor α (PDGFRα) via PDGF, indirect activation via growth factors outside the PDGF family failed to induce dimerization, internalization, and degradation of PDGFRα. Chronically activated, monomeric PDGFRα induced prolonged activation of Akt and suppressed the level of p53. These events were sufficient to promote both cellular responses (proliferation, survival, and contraction) that are intrinsic to proliferative vitreoretinopathy (PVR) and induce the disease itself. This signature signaling pathway appeared to extend beyond PVR since deregulating PDGFRα in ways that promote solid tumors also resulted in chronic activation of Akt and a decline in the level of p53. PMID:21357737

  6. Fibroblast growth factor-2 induces osteogenic differentiation through a Runx2 activation in vascular smooth muscle cells

    SciTech Connect

    Nakahara, Takehiro; Sato, Hiroko; Shimizu, Takehisa; Tanaka, Toru; Matsui, Hiroki; Kawai-Kowase, Keiko; Sato, Mahito; Iso, Tatsuya; Arai, Masashi; Kurabayashi, Masahiko

    2010-04-02

    Expression of bone-associated proteins and osteoblastic transcription factor Runx2 in arterial cells has been implicated in the development of vascular calcification. However, the signaling upstream of the Runx2-mediated activation of osteoblastic program in vascular smooth muscle cells (VSMC) is poorly understood. We examined the effects of fibroblast growth factor-2 (FGF-2), an important regulator of bone formation, on osteoblastic differentiation of VSMC. Stimulation of cultured rat aortic SMC (RASMC) with FGF-2 induced the expression of the osteoblastic markers osteopontin (OPN) and osteocalcin. Luciferase assays showed that FGF-2 induced osteocyte-specific element (OSE)-dependent transcription. Downregulation of Runx2 by siRNA repressed the basal and FGF-2-stimulated expression of the OPN gene in RASMC. FGF-2 produced hydrogen peroxide in RASMC, as evaluated by fluorescent probe. Induction of OPN expression by FGF-2 was inhibited not only by PD98059 (MEK1 inhibitor) and PP1 (c-Src inhibitor), but also by an antioxidant, N-acetyl cysteine. Nuclear extracts from FGF-2-treated RASMC exhibited increased DNA-binding of Runx2 to its target sequence. Immunohistochemistry of human coronary atherectomy specimens and calcified aortic tissues showed that expression of FGF receptor-1 and Runx2 was colocalized. In conclusion, these results suggest that FGF-2 plays a role in inducing osteoblastic differentiation of VSMC by activating Runx2 through mitogen-activated protein kinase (MAPK)-dependent- and oxidative stress-sensitive-signaling pathways.

  7. The effect of anisotropic collagen-GAG scaffolds and growth factor supplementation on tendon cell recruitment, alignment, and metabolic activity

    PubMed Central

    Caliari, Steven R.; Harley, Brendan A.C.

    2014-01-01

    Current surgical and tissue engineering approaches for treating tendon injuries have shown limited success, suggesting the need for new biomaterial strategies. Here we describe the development of an anisotropic collagen-glycosaminoglycan (CG) scaffold and use of growth factor supplementation strategies to create a 3D platform for tendon tissue engineering. We fabricated cylindrical CG scaffolds with aligned tracks of ellipsoidal pores that mimic the native physiology of tendon by incorporating a directional solidification step into a conventional lyophilization strategy. By modifying the freezing temperature, we created a homologous series of aligned CG scaffolds with constant relative density and degree of anisotropy but a range of pore sizes (55–243 μm). Equine tendon cells showed greater levels of attachment, metabolic activity, and alignment as well as less cell-mediated scaffold contraction, when cultured in anisotropic scaffolds compared to an isotropic CG scaffold control. The anisotropic CG scaffolds also provided critical contact guidance cues for cell alignment. While tendon cells were randomly oriented in the isotropic control scaffold and the transverse (unaligned) plane of the anisotropic scaffolds, significant cell alignment was observed in the direction of the contact guidance cues in the longitudinal plane of the anisotropic scaffolds. Scaffold pore size was found to significantly influence tendon cell viability, proliferation, penetration into the scaffold, and metabolic activity in a manner predicted by cellular solids arguments. Finally, the addition of the growth factors PDGF-BB and IGF-1 to aligned CG scaffolds was found to enhance tendon cell motility, viability, and metabolic activity in dose-dependent manners. This work suggests a composite strategy for developing bioactive, 3D material systems for tendon tissue engineering. PMID:21550653

  8. NF-κB Activation Limits Airway Branching through Inhibition of Sp1-Mediated Fibroblast Growth Factor-10 Expression

    PubMed Central

    Benjamin, John T.; Carver, Billy J.; Plosa, Erin J.; Yamamoto, Yasutoshi; Miller, J. Davin; Liu, Jin-Hua; van der Meer, Riet; Blackwell, Timothy S.; Prince, Lawrence S.

    2015-01-01

    Bronchopulmonary dysplasia (BPD) is a frequent complication of preterm birth. This chronic lung disease results from arrested saccular airway development and is most common in infants exposed to inflammatory stimuli. In experimental models, inflammation inhibits expression of fibroblast growth factor-10 (FGF-10) and impairs epithelial–mesenchymal interactions during lung development; however, the mechanisms connecting inflammatory signaling with reduced growth factor expression are not yet understood. In this study we found that soluble inflammatory mediators present in tracheal fluid from preterm infants can prevent saccular airway branching. In addition, LPS treatment led to local production of mediators that inhibited airway branching and FGF-10 expression in LPS-resistant C.C3-Tlr4Lpsd/J fetal mouse lung explants. Both direct NF-κB activation and inflammatory cytokines (IL-1β and TNF-α) that activate NF-κB reduced FGF-10 expression, whereas chemokines that signal via other inflammatory pathways had no effect. Mutational analysis of the FGF-10 promoter failed to identify genetic elements required for direct NF-κB–mediated FGF-10 inhibition. Instead, NF-κB activation appeared to interfere with the normal stimulation of FGF-10 expression by Sp1. Chromatin immunoprecipitation and nuclear coimmunoprecipitation studies demonstrated that the RelA subunit of NF-κB and Sp1 physically interact at the FGF-10 promoter. These findings indicate that inflammatory signaling through NF-κB disrupts the normal expression of FGF-10 in fetal lung mesenchyme by interfering with the transcriptional machinery critical for lung morphogenesis. PMID:20861353

  9. Satellite cell activation in stretched skeletal muscle and the role of nitric oxide and hepatocyte growth factor.

    PubMed

    Tatsumi, Ryuichi; Liu, Xiaosong; Pulido, Antonio; Morales, Mark; Sakata, Tomowa; Dial, Sharon; Hattori, Akihito; Ikeuchi, Yoshihide; Allen, Ronald E

    2006-06-01

    In the present study, we examined the roles of hepatocyte growth factor (HGF) and nitric oxide (NO) in the activation of satellite cells in passively stretched rat skeletal muscle. A hindlimb suspension model was developed in which the vastus, adductor, and gracilis muscles were subjected to stretch for 1 h. Satellite cells were activated by stretch determined on the basis of 5-bromo-2'-deoxyuridine (BrdU) incorporation in vivo. Extracts from stretched muscles stimulated BrdU incorporation in freshly isolated control rat satellite cells in a concentration-dependent manner. Extracts from stretched muscles contained the active form of HGF, and the satellite cell-activating activity could be neutralized by incubation with anti-HGF antibody. The involvement of NO was investigated by administering nitro-L-arginine methyl ester (L-NAME) or the inactive enantiomer N(G)-nitro-D-arginine methyl ester HCl (D-NAME) before stretch treatment. In vivo activation of satellite cells in stretched muscle was not inhibited by D-NAME but was inhibited by L-NAME. The activity of stretched muscle extract was abolished by L-NAME treatment but could be restored by the addition of HGF, indicating that the extract was not inhibitory. Finally, NO synthase activity in stretched and unstretched muscles was assayed in muscle extracts immediately after 2-h stretch treatment and was found to be elevated in stretched muscle but not in stretched muscle from L-NAME-treated rats. The results of these experiments demonstrate that stretching muscle liberates HGF in a NO-dependent manner, which can activate satellite cells.

  10. Adenovector-mediated gene transfer of active transforming growth factor-beta1 induces prolonged severe fibrosis in rat lung.

    PubMed Central

    Sime, P J; Xing, Z; Graham, F L; Csaky, K G; Gauldie, J

    1997-01-01

    Transforming growth factor (TGF)-beta1 has been implicated in the pathogenesis of fibrosis based upon its matrix-inducing effects on stromal cells in vitro, and studies demonstrating increased expression of total TGF-beta1 in fibrotic tissues from a variety of organs. The precise role in vivo of this cytokine in both its latent and active forms, however, remains unclear. Using replication-deficient adenovirus vectors to transfer the cDNA of porcine TGF-beta1 to rat lung, we have been able to study the effect of TGF-beta1 protein in the respiratory tract directly. We have demonstrated that transient overexpression of active, but not latent, TGF-beta1 resulted in prolonged and severe interstitial and pleural fibrosis characterized by extensive deposition of the extracellular matrix (ECM) proteins collagen, fibronectin, and elastin, and by emergence of cells with the myofibroblast phenotype. These results illustrate the role of TGF-beta1 and the importance of its activation in the pulmonary fibrotic process, and suggest that targeting active TGF-beta1 and steps involved in TGF-beta1 activation are likely to be valuable antifibrogenic therapeutic strategies. This new and versatile model of pulmonary fibrosis can be used to study such therapies. PMID:9259574

  11. Lipopolysaccharide (LPS)-Induced Biliary Epithelial Cell NRas Activation Requires Epidermal Growth Factor Receptor (EGFR).

    PubMed

    Trussoni, Christy E; Tabibian, James H; Splinter, Patrick L; O'Hara, Steven P

    2015-01-01

    Cholangiocytes (biliary epithelial cells) actively participate in microbe-induced proinflammatory responses in the liver and contribute to inflammatory and infectious cholangiopathies. We previously demonstrated that cholangiocyte TLR-dependent NRas activation contributes to proinflammatory/ proliferative responses. We test the hypothesis that LPS-induced activation of NRas requires the EGFR. SV40-transformed human cholangiocytes (H69 cells), or low passage normal human cholangiocytes (NHC), were treated with LPS in the presence or absence of EGFR or ADAM metallopeptidase domain 17 (TACE) inhibitors. Ras activation assays, quantitative RT-PCR, and proliferation assays were performed in cells cultured with or without inhibitors or an siRNA to Grb2. Immunofluorescence for phospho-EGFR was performed on LPS-treated mouse samples and specimens from patients with primary sclerosing cholangitis, primary biliary cirrhosis, hepatitis C, and normal livers. LPS-treatment induced an association between the TLR/MyD88 and EGFR/Grb2 signaling apparatus, NRas activation, and EGFR phosphorylation. NRas activation was sensitive to EGFR and TACE inhibitors and correlated with EGFR phosphorylation. The TACE inhibitor and Grb2 depletion prevented LPS-induced IL6 expression (p<0.05) and proliferation (p<0.01). Additionally, cholangiocytes from LPS-treated mouse livers and human primary sclerosing cholangitis (PSC) livers exhibited increased phospho-EGFR (p<0.01). Moreover, LPS-induced mouse cholangiocyte proliferation was inhibited by concurrent treatment with the EGFR inhibitor, Erlotinib. Our results suggest that EGFR is essential for LPS-induced, TLR4/MyD88-mediated NRas activation and induction of a robust proinflammatory cholangiocyte response. These findings have implications not only for revealing the signaling potential of TLRs, but also implicate EGFR as an integral component of cholangiocyte TLR-induced proinflammatory processes.

  12. Autocrine growth factors and solid tumor malignancy.

    PubMed Central

    Walsh, J. H.; Karnes, W. E.; Cuttitta, F.; Walker, A.

    1991-01-01

    The ability of malignant cells to escape the constraint that normally regulate cell growth and differentiation has been a primary focus of attention for investigators of cancer cell biology. An outcome of this attention has been the discovery that the protein products of oncogenes play a role in the activation of growth signal pathways. A second outcome, possibly related to abnormal oncogene expression, has been the discovery that malignant cells frequently show an ability to regulate their own growth by the release of autocrine growth modulatory substances. Most important, the growth of certain malignant cell types has been shown to depend on autocrine growth circuits. A malignant tumor whose continued growth depends on the release of an autocrine growth factor may be vulnerable to treatment with specific receptor antagonists or immunoneutralizing antibodies designed to break the autocrine circuit. Information is rapidly emerging concerning autocrine growth factors in selected human solid tissue malignancy. Images PMID:1926844

  13. Transforming Growth Factor-β: Activation by Neuraminidase and Role in Highly Pathogenic H5N1 Influenza Pathogenesis

    PubMed Central

    Moser, Lindsey A.; O'Brien, Kevin B.; Cline, Troy D.; Jones, Jeremy C.; Tumpey, Terrence M.; Katz, Jacqueline M.; Kelley, Laura A.; Gauldie, Jack; Schultz-Cherry, Stacey

    2010-01-01

    Transforming growth factor-beta (TGF-β), a multifunctional cytokine regulating several immunologic processes, is expressed by virtually all cells as a biologically inactive molecule termed latent TGF-β (LTGF-β). We have previously shown that TGF-β activity increases during influenza virus infection in mice and suggested that the neuraminidase (NA) protein mediates this activation. In the current study, we determined the mechanism of activation of LTGF-β by NA from the influenza virus A/Gray Teal/Australia/2/1979 by mobility shift and enzyme inhibition assays. We also investigated whether exogenous TGF-β administered via a replication-deficient adenovirus vector provides protection from H5N1 influenza pathogenesis and whether depletion of TGF-β during virus infection increases morbidity in mice. We found that both the influenza and bacterial NA activate LTGF-β by removing sialic acid motifs from LTGF-β, each NA being specific for the sialic acid linkages cleaved. Further, NA likely activates LTGF-β primarily via its enzymatic activity, but proteases might also play a role in this process. Several influenza A virus subtypes (H1N1, H1N2, H3N2, H5N9, H6N1, and H7N3) except the highly pathogenic H5N1 strains activated LTGF-β in vitro and in vivo. Addition of exogenous TGF-β to H5N1 influenza virus–infected mice delayed mortality and reduced viral titers whereas neutralization of TGF-β during H5N1 and pandemic 2009 H1N1 infection increased morbidity. Together, these data show that microbe-associated NAs can directly activate LTGF-β and that TGF-β plays a pivotal role protecting the host from influenza pathogenesis. PMID:20949074

  14. Oncogenes, genes, and growth factors

    SciTech Connect

    Guroff, G.

    1989-01-01

    This book contains 12 chapters. Some of the chapter titles are: The Epidermal Growth Factor Receptor Gene; Structure and Expression of the Nerve Growth Factor Gene; The Erythropoietin Gene; The Interleukin-2 Gene; The Transferrin Gene; and The Transferrin Receptor Gene.

  15. Extended Synaptotagmin Interaction with the Fibroblast Growth Factor Receptor Depends on Receptor Conformation, Not Catalytic Activity.

    PubMed

    Tremblay, Michel G; Herdman, Chelsea; Guillou, François; Mishra, Prakash K; Baril, Joëlle; Bellenfant, Sabrina; Moss, Tom

    2015-06-26

    We previously demonstrated that ESyt2 interacts specifically with the activated FGF receptor and is required for a rapid phase of receptor internalization and for functional signaling via the ERK pathway in early Xenopus embryos. ESyt2 is one of the three-member family of Extended Synaptotagmins that were recently shown to be implicated in the formation of endoplasmic reticulum (ER)-plasma membrane (PM) junctions and in the Ca(2+) dependent regulation of these junctions. Here we show that ESyt2 is directed to the ER by its putative transmembrane domain, that the ESyts hetero- and homodimerize, and that ESyt2 homodimerization in vivo requires a TM adjacent sequence but not the SMP domain. ESyt2 and ESyt3, but not ESyt1, selectively interact in vivo with activated FGFR1. In the case of ESyt2, this interaction requires a short TM adjacent sequence and is independent of receptor autophosphorylation, but dependent on receptor conformation. The data show that ESyt2 recognizes a site in the upper kinase lobe of FGFR1 that is revealed by displacement of the kinase domain activation loop during receptor activation.

  16. Growth factor involvement in tension-induced skeletal muscle growth

    NASA Technical Reports Server (NTRS)

    Vandenburgh, Herman H.

    1993-01-01

    Long-term manned space travel will require a better understanding of skeletal muscle atrophy which results from microgravity. Astronaut strength and dexterity must be maintained for normal mission operations and for emergency situations. Although exercise in space slows the rate of muscle loss, it does not prevent it. A biochemical understanding of how gravity/tension/exercise help to maintain muscle size by altering protein synthesis and/or degradation rate should ultimately allow pharmacological intervention to prevent muscle atrophy in microgravity. The overall objective is to examine some of the basic biochemical processes involved in tension-induced muscle growth. With an experimental in vitro system, the role of exogenous and endogenous muscle growth factors in mechanically stimulated muscle growth are examined. Differentiated avian skeletal myofibers can be 'exercised' in tissue culture using a newly developed dynamic mechanical cell stimulator device which simulates different muscle activity patterns. Patterns of mechanical activity which significantly affect muscle growth and metabolic characteristics were found. Both exogenous and endogenous growth factors are essential for tension-induced muscle growth. Exogenous growth factors found in serum, such as insulin, insulin-like growth factors, and steroids, are important regulators of muscle protein turnover rates and mechanically-induced muscle growth. Endogenous growth factors are synthesized and released into the culture medium when muscle cells are mechanically stimulated. At least one family of mechanically induced endogenous factors, the prostaglandins, help to regulate the rates of protein turnover in muscle cells. Endogenously synthesized IGF-1 is another. The interaction of muscle mechanical activity and these growth factors in the regulation of muscle protein turnover rates with our in vitro model system is studied.

  17. Transforming growth factor β-activated kinase 1 negatively regulates interleukin-1α-induced stromal-derived factor-1 expression in vascular smooth muscle cells

    SciTech Connect

    Yang, Bin; Li, Wei; Zheng, Qichang; Qin, Tao; Wang, Kun; Li, Jinjin; Guo, Bing; Yu, Qihong; Wu, Yuzhe; Gao, Yang; Cheng, Xiang; Hu, Shaobo; Kumar, Stanley Naveen; Liu, Sanguang; Song, Zifang

    2015-07-17

    Stromal-derived Factor-1 (SDF-1) derived from vascular smooth muscle cells (VSMCs) contributes to vascular repair and remodeling in various vascular diseases. In this study, the mechanism underlying regulation of SDF-1 expression by interleukin-1α (IL-1α) was investigated in primary rat VSMCs. We found IL-1α promotes SDF-1 expression by up-regulating CCAAT-enhancer-binding protein β (C/EBPβ) in an IκB kinase β (IKKβ) signaling-dependent manner. Moreover, IL-1α-induced expression of C/EBPβ and SDF-1 was significantly potentiated by knockdown of transforming growth factor β-activated kinase 1 (TAK1), an upstream activator of IKKβ signaling. In addition, we also demonstrated that TAK1/p38 mitogen-activated protein kinase (p38 MAPK) signaling exerted negative effect on IL-1α-induced expression of C/EBPβ and SDF-1 through counteracting ROS-dependent up-regulation of nuclear factor erythroid 2-related factor 2 (NRF2). In conclusion, TAK1 acts as an important regulator of IL-1α-induced SDF-1 expression in VSMCs, and modulating activity of TAK1 may serve as a potential strategy for modulating vascular repair and remodeling. - Highlights: • IL-1α induces IKKβ signaling-dependent SDF-1 expression by up-regulating C/EBPβ. • Activation of TAK1 by IL-1α negatively regulates C/EBPβ-dependent SDF-1 expression. • IL-1α-induced TAK1/p38 MAPK signaling counteracts ROS-dependent SDF-1 expression. • TAK1 counteracts IL-1α-induced SDF-1 expression by attenuating NRF2 up-regulation.

  18. Epiderstatin, a new inhibitor of the mitogenic activity induced by epidermal growth factor. I. Taxonomy, fermentation, isolation and characterization.

    PubMed

    Osada, H; Sonoda, T; Kusakabe, H; Isono, K

    1989-11-01

    Inhibitors of mitogenic activity induced by epidermal growth factor (EGF) were screened from culture broths of soil microorganisms. A strain of actinomycetes has been found to produce a new glutarimide antibiotic named epiderstatin which inhibits the incorporation of [3H]thymidine into quiescent animal cells stimulated by EGF. Taxonomic studies have revealed that the producing strain belongs to a subspecies of Streptomyces pulveraceus, thus the name, Streptomyces pulveraceus subsp. epiderstagenes was given to this strain. The molecular formula (C15H20N2O4) and UV profile (lambda max 295 nm) of the antibiotic are distinct from other known antibiotics. It inhibited the incorporation of [3H]thymidine into quiescent cells stronger than into growing cells. PMID:2584144

  19. Insulin-like growth factor I enhances proenkephalin synthesis and dopamine. beta. -hydroxylase activity in adrenal chromaffin cells

    SciTech Connect

    Wilson, S.P. )

    1991-01-01

    Insulin-like growth factor I (IGF-I) increased both the contents of proenkephalin derived enkephalin-containing peptides and the activity of dopamine {beta}-hydroxylase in bovine adrenal chromaffin cells. These increases in dopamine {beta}-hydroxylase and enkephalin-containing peptides continued for at least 8 days. The half-maximal IGF-I concentration for these effects was {approximately} 1 nM, with maximal effects observed at 10-30 nM. In contrast, insulin was 1,000-fold less potent. Pretreatment of chromaffin cells with IGF-I increased the rate of ({sup 35}S)proenkephalin synthesis 4-fold compared to untreated cells. Total protein synthesis increased only 1.5-fold under these conditions. These results suggest that IGF-I may be a normal regulator of chromaffin cell function.

  20. Constitutive activation of transforming growth factor Beta receptor 1 in the mouse uterus impairs uterine morphology and function.

    PubMed

    Gao, Yang; Duran, Samantha; Lydon, John P; DeMayo, Francesco J; Burghardt, Robert C; Bayless, Kayla J; Bartholin, Laurent; Li, Qinglei

    2015-02-01

    Despite increasing evidence pointing to the essential involvement of the transforming growth factor beta (TGFB) superfamily in reproduction, a definitive role of TGFB signaling in the uterus remains to be unveiled. In this study, we generated a gain-of-function mouse model harboring a constitutively active (CA) TGFB receptor 1 (TGFBR1), the expression of which was conditionally induced by the progesterone receptor (Pgr)-Cre recombinase. Overactivation of TGFB signaling was verified by enhanced phosphorylation of SMAD2 and increased expression of TGFB target genes in the uterus. TGFBR1 Pgr-Cre CA mice were sterile. Histological, cellular, and molecular analyses demonstrated that constitutive activation of TGFBR1 in the mouse uterus promoted formation of hypermuscled uteri. Accompanying this phenotype was the upregulation of a battery of smooth muscle genes in the uterus. Furthermore, TGFB ligands activated SMAD2/3 and stimulated the expression of a smooth muscle maker gene, alpha smooth muscle actin (ACTA2), in human uterine smooth muscle cells. Immunofluorescence microscopy identified a marked reduction of uterine glands in TGFBR1 Pgr-Cre CA mice within the endometrial compartment that contained myofibroblast-like cells. Thus, constitutive activation of TGFBR1 in the mouse uterus caused defects in uterine morphology and function, as evidenced by abnormal myometrial structure, dramatically reduced uterine glands, and impaired uterine decidualization. These results underscore the importance of a precisely controlled TGFB signaling system in establishing a uterine microenvironment conducive to normal development and function.

  1. Constitutive Activation of Transforming Growth Factor Beta Receptor 1 in the Mouse Uterus Impairs Uterine Morphology and Function1

    PubMed Central

    Gao, Yang; Duran, Samantha; Lydon, John P.; DeMayo, Francesco J.; Burghardt, Robert C.; Bayless, Kayla J.; Bartholin, Laurent; Li, Qinglei

    2014-01-01

    ABSTRACT Despite increasing evidence pointing to the essential involvement of the transforming growth factor beta (TGFB) superfamily in reproduction, a definitive role of TGFB signaling in the uterus remains to be unveiled. In this study, we generated a gain-of-function mouse model harboring a constitutively active (CA) TGFB receptor 1 (TGFBR1), the expression of which was conditionally induced by the progesterone receptor (Pgr)-Cre recombinase. Overactivation of TGFB signaling was verified by enhanced phosphorylation of SMAD2 and increased expression of TGFB target genes in the uterus. TGFBR1 Pgr-Cre CA mice were sterile. Histological, cellular, and molecular analyses demonstrated that constitutive activation of TGFBR1 in the mouse uterus promoted formation of hypermuscled uteri. Accompanying this phenotype was the upregulation of a battery of smooth muscle genes in the uterus. Furthermore, TGFB ligands activated SMAD2/3 and stimulated the expression of a smooth muscle maker gene, alpha smooth muscle actin (ACTA2), in human uterine smooth muscle cells. Immunofluorescence microscopy identified a marked reduction of uterine glands in TGFBR1 Pgr-Cre CA mice within the endometrial compartment that contained myofibroblast-like cells. Thus, constitutive activation of TGFBR1 in the mouse uterus caused defects in uterine morphology and function, as evidenced by abnormal myometrial structure, dramatically reduced uterine glands, and impaired uterine decidualization. These results underscore the importance of a precisely controlled TGFB signaling system in establishing a uterine microenvironment conducive to normal development and function. PMID:25505200

  2. Intracellular protein delivery activity of peptides derived from insulin-like growth factor binding proteins 3 and 5

    SciTech Connect

    Goda, Natsuko; Tenno, Takeshi; Inomata, Kosuke; Shirakawa, Masahiro; Tanaka, Toshiki; Hiroaki, Hidekazu

    2008-08-01

    Insulin-like growth factor binding proteins (IGFBPs) have various IGF-independent cellular activities, including receptor-independent cellular uptake followed by transcriptional regulation, although mechanisms of cellular entry remain unclear. Herein, we focused on their receptor-independent cellular entry mechanism in terms of protein transduction domain (PTD) activity, which is an emerging technique useful for clinical applications. The peptides of 18 amino acid residues derived from IGFBP-3 and IGFBP-5, which involve heparin-binding regions, mediated cellular delivery of an exogenous protein into NIH3T3 and HeLa cells. Relative protein delivery activities of IGFBP-3/5-derived peptides were approximately 20-150% compared to that of the HIV-Tat peptide, a potent PTD. Heparin inhibited the uptake of the fusion proteins with IGFBP-3 and IGFBP-5, indicating that the delivery pathway is heparin-dependent endocytosis, similar to that of HIV-Tat. The delivery of GST fused to HIV-Tat was competed by either IGFBP-3 or IGFBP-5-derived synthetic peptides. Therefore, the entry pathways of the three PTDs are shared. Our data has shown a new approach for designing protein delivery systems using IGFBP-3/5 derived peptides based on the molecular mechanisms of IGF-independent activities of IGFBPs.

  3. Osmotic Stress, not Aldose Reductase Activity, Directly induces Growth Factors and MAPK Signaling changes during Sugar Cataract Formation

    PubMed Central

    Zhang, Peng; Xing, Kuiyi; Randazzo, James; Blessing, Karen; Lou, Marjorie F.; Kador, Peter F.

    2012-01-01

    In sugar cataract formation in rats, aldose reductase (AR) actitvity is not only linked to lenticular sorbitol (diabetic) or galactitol (galactosemic) formation but also to signal transduction changes, cytotoxic signals and activation of apoptosis. Using both in vitro and in vivo techniques, the interrelationship between AR activity, polyol (sorbitol and galactitol) formation, osmotic stress, growth factor induction, and cell signaling changes have been investigated. For in vitro studies, lenses from Sprague Dawley rats were cultured for up to 48 hrs in TC-199-bicarbonate media containing either 30 mM fructose (control), or 30 mM glucose or galctose with/without the aldose reductase inhibitors AL1576 or tolrestat, the sorbitol dehydrogenase inhibitor (SDI) CP-470,711, or 15 mM mannitol (osmotic-compensated media). For in vivo studies, lenses were obtained from streptozotocin-induced diabetic Sprague Dawley rats fed diet with/without the ARIs AL1576 or tolrestat for 10 weeks. As expected, lenses cultured in high glucose / galactose media or from untreated diabetic rats all showed a decrease in the GSH pool that was lessened by ARI treatment. Lenses either from diabetic rats or from glucose/galactose culture conditions showed increased expression of basic-FGF, TGF-β, and increased signaling through P-Akt, P-ERK1/2 and P-SAPK/JNK which were also normalized by ARIs to the expression levels observed in non-diabetic controls. Culturing rat lenses in osomotically compensated media containing 30 mM glucose or galactose did not lead to increased growth factor expression or altered signaling. These studies indicate that it is the biophysical response of the lens to osmotic stress that results in an increased intralenticular production of basic-FGF and TGF-β and the altered cytotoxic signaling that is observed during sugar cataract formation. PMID:22710095

  4. Brain-derived neurotrophic factor inhibits osmotic swelling of rat retinal glial (Müller) and bipolar cells by activation of basic fibroblast growth factor signaling.

    PubMed

    Berk, B-A; Vogler, S; Pannicke, T; Kuhrt, H; Garcia, T B; Wiedemann, P; Reichenbach, A; Seeger, J; Bringmann, A

    2015-06-01

    Water accumulation in retinal glial (Müller) and neuronal cells resulting in cellular swelling contributes to the development of retinal edema and neurodegeneration. Intravitreal administration of neurotrophins such as brain-derived neurotrophic factor (BDNF) is known to promote survival of retinal neurons. Here, we show that exogenous BDNF inhibits the osmotic swelling of Müller cell somata induced by superfusion of rat retinal slices or freshly isolated cells with a hypoosmotic solution containing barium ions. BDNF also inhibited the osmotic swelling of bipolar cell somata in retinal slices, but failed to inhibit the osmotic soma swelling of freshly isolated bipolar cells. The inhibitory effect of BDNF on Müller cell swelling was mediated by activation of tropomyosin-related kinase B (TrkB) and transactivation of fibroblast growth factor receptors. Exogenous basic fibroblast growth factor (bFGF) fully inhibited the osmotic swelling of Müller cell somata while it partially inhibited the osmotic swelling of bipolar cell somata. Isolated Müller cells displayed immunoreactivity of truncated TrkB, but not full-length TrkB. Isolated rod bipolar cells displayed immunoreactivities of both TrkB isoforms. Data suggest that the neuroprotective effect of exogenous BDNF in the retina is in part mediated by prevention of the cytotoxic swelling of retinal glial and bipolar cells. While BDNF directly acts on Müller cells by activation of TrkB, BDNF indirectly acts on bipolar cells by inducing glial release of factors like bFGF that inhibit bipolar cell swelling.

  5. In vivo transformation of factor-dependent hemopoietic cells: role of intracisternal A-particle transposition for growth factor gene activation.

    PubMed Central

    Dührsen, U; Stahl, J; Gough, N M

    1990-01-01

    Cells of the granulocyte-macrophage colony stimulating factor (GM-CSF) or multi-lineage colony stimulating factor (Multi-CSF) dependent line FDC-P1 undergo leukemic transformation after injection into irradiated DBA/2 mice. About one third of factor-independent FDC-P1 variants isolated from leukemic animals express GM-CSF or Multi-CSF, assessed either by bioassay or by sensitive RNA detection using the polymerase chain reaction. All of the GM-CSF-secreting lines studied had a rearrangement in one allele of the GM-CSF gene, three of four Multi-CSF-secreting lines had Multi-CSF gene rearrangements, while factor-independent lines lacking evidence of growth factor production had no demonstrable CSF gene alterations. All rearrangements were characterized by insertions of novel DNA in the 5'-flanking regions of the CSF genes. The inserted segments of DNA varied in size between 0.35 and 6.5 kb and displayed restriction enzyme cleavage maps reminiscent of intracisternal A-particle (IAP) genomes. This was confirmed in two cases by molecular cloning and nucleotide sequence analysis. In these instances, the insertion consisted of solitary IAP long terminal repeats. The transformation system described provides a model for the study of IAP transpositions and their effects on gene activation. Images Fig. 2. Fig. 3. Fig. 4. Fig. 6. Fig. 9. PMID:2108861

  6. Circulating Fibroblast Growth Factor-2, HIV-Tat, and Vascular Endothelial Cell Growth Factor-A in HIV-Infected Children with Renal Disease Activate Rho-A and Src in Cultured Renal Endothelial Cells

    PubMed Central

    Das, Jharna R; Gutkind, J. Silvio; Ray, Patricio E

    2016-01-01

    Renal endothelial cells (REc) are the first target of HIV-1 in the kidney. The integrity of REc is maintained at least partially by heparin binding growth factors that bind to heparan sulfate proteoglycans located on their cell surface. However, previous studies showed that the accumulation of two heparin-binding growth factors, Vascular Endothelial Cell Growth Factor-A (VEGF-A) and Fibroblast Growth Factor-2 (FGF-2), in combination with the viral protein Tat, can precipitate the progression of HIV-renal diseases. Nonetheless, very little is known about how these factors affect the behavior of REc in HIV+ children. We carried out this study to determine how VEGF-A, FGF-2, and HIV-Tat, modulate the cytoskeletal structure and permeability of cultured REc, identify key signaling pathways involved in this process, and develop a functional REc assay to detect HIV+ children affected by these changes. We found that VEGF-A and FGF-2, acting in synergy with HIV-Tat and heparin, affected the cytoskeletal structure and permeability of REc through changes in Rho-A, Src, and Rac-1 activity. Furthermore, urine samples from HIV+ children with renal diseases, showed high levels of VEGF-A and FGF-2, and induced similar changes in cultured REc and podocytes. These findings suggest that FGF-2, VEGF-A, and HIV-Tat, may affect the glomerular filtration barrier in HIV+ children through the induction of synergistic changes in Rho-A and Src activity. Further studies are needed to define the clinical value of the REc assay described in this study to identify HIV+ children exposed to circulating factors that may induce glomerular injury through similar mechanisms. PMID:27097314

  7. Circulating Fibroblast Growth Factor-2, HIV-Tat, and Vascular Endothelial Cell Growth Factor-A in HIV-Infected Children with Renal Disease Activate Rho-A and Src in Cultured Renal Endothelial Cells.

    PubMed

    Das, Jharna R; Gutkind, J Silvio; Ray, Patricio E

    2016-01-01

    Renal endothelial cells (REc) are the first target of HIV-1 in the kidney. The integrity of REc is maintained at least partially by heparin binding growth factors that bind to heparan sulfate proteoglycans located on their cell surface. However, previous studies showed that the accumulation of two heparin-binding growth factors, Vascular Endothelial Cell Growth Factor-A (VEGF-A) and Fibroblast Growth Factor-2 (FGF-2), in combination with the viral protein Tat, can precipitate the progression of HIV-renal diseases. Nonetheless, very little is known about how these factors affect the behavior of REc in HIV+ children. We carried out this study to determine how VEGF-A, FGF-2, and HIV-Tat, modulate the cytoskeletal structure and permeability of cultured REc, identify key signaling pathways involved in this process, and develop a functional REc assay to detect HIV+ children affected by these changes. We found that VEGF-A and FGF-2, acting in synergy with HIV-Tat and heparin, affected the cytoskeletal structure and permeability of REc through changes in Rho-A, Src, and Rac-1 activity. Furthermore, urine samples from HIV+ children with renal diseases, showed high levels of VEGF-A and FGF-2, and induced similar changes in cultured REc and podocytes. These findings suggest that FGF-2, VEGF-A, and HIV-Tat, may affect the glomerular filtration barrier in HIV+ children through the induction of synergistic changes in Rho-A and Src activity. Further studies are needed to define the clinical value of the REc assay described in this study to identify HIV+ children exposed to circulating factors that may induce glomerular injury through similar mechanisms.

  8. Circulating Fibroblast Growth Factor-2, HIV-Tat, and Vascular Endothelial Cell Growth Factor-A in HIV-Infected Children with Renal Disease Activate Rho-A and Src in Cultured Renal Endothelial Cells.

    PubMed

    Das, Jharna R; Gutkind, J Silvio; Ray, Patricio E

    2016-01-01

    Renal endothelial cells (REc) are the first target of HIV-1 in the kidney. The integrity of REc is maintained at least partially by heparin binding growth factors that bind to heparan sulfate proteoglycans located on their cell surface. However, previous studies showed that the accumulation of two heparin-binding growth factors, Vascular Endothelial Cell Growth Factor-A (VEGF-A) and Fibroblast Growth Factor-2 (FGF-2), in combination with the viral protein Tat, can precipitate the progression of HIV-renal diseases. Nonetheless, very little is known about how these factors affect the behavior of REc in HIV+ children. We carried out this study to determine how VEGF-A, FGF-2, and HIV-Tat, modulate the cytoskeletal structure and permeability of cultured REc, identify key signaling pathways involved in this process, and develop a functional REc assay to detect HIV+ children affected by these changes. We found that VEGF-A and FGF-2, acting in synergy with HIV-Tat and heparin, affected the cytoskeletal structure and permeability of REc through changes in Rho-A, Src, and Rac-1 activity. Furthermore, urine samples from HIV+ children with renal diseases, showed high levels of VEGF-A and FGF-2, and induced similar changes in cultured REc and podocytes. These findings suggest that FGF-2, VEGF-A, and HIV-Tat, may affect the glomerular filtration barrier in HIV+ children through the induction of synergistic changes in Rho-A and Src activity. Further studies are needed to define the clinical value of the REc assay described in this study to identify HIV+ children exposed to circulating factors that may induce glomerular injury through similar mechanisms. PMID:27097314

  9. Ultraviolet B-induced activated protein-1 activation does not require epidermal growth factor receptor but is blocked by a dominant negative PKClambda/iota.

    PubMed

    Huang, C; Ma, W y; Bowden, G T; Dong, Z

    1996-12-01

    The exposure of mammalian cells to UV irradiation leads to the activation of transcription factors such as activated protein-1 (AP-1) and NFkappaB. It is postulated that epidermal growth factor (EGF) receptor, but not protein kinase C (PKC), is the major membrane mediator in UV-induced signal transduction. Since UVB is responsible for most of the carcinogenic effects of sun exposure, we investigated the role of EGF receptors and PKC in UVB-induced AP-1 activation. Our results indicated that while the down-regulation of novel PKC (nPKC) and conventional PKC (cPKC) by pretreatment of cells with 12-O-tetradecanoyl phorbol-13-acetate cannot block UVB-induced AP-1 activity, it can block 12-O-tetradecanoyl phorbol-13-acetate-induced AP-1 activity. Further, the dominant negative mutant PKClambda/iota blocked UVB-induced AP-1 activity in all doses and time courses studied. In contrast, UVB-induced AP-1 activity from cells devoid of EGF receptor (B82) was not significantly different from that of the stable transfectants with a kinase-deficient EGF receptor (B82M721) or those with a wild-type EGF receptor (B82L) at all UVB irradiation doses and time courses studied. All of this evidence indicated that aPKC, but not EGF receptor, is involved in UVB-induced AP-1 activation. PMID:8940130

  10. Growth factor transgenes interactively regulate articular chondrocytes.

    PubMed

    Shi, Shuiliang; Mercer, Scott; Eckert, George J; Trippel, Stephen B

    2013-04-01

    Adult articular chondrocytes lack an effective repair response to correct damage from injury or osteoarthritis. Polypeptide growth factors that stimulate articular chondrocyte proliferation and cartilage matrix synthesis may augment this response. Gene transfer is a promising approach to delivering such factors. Multiple growth factor genes regulate these cell functions, but multiple growth factor gene transfer remains unexplored. We tested the hypothesis that multiple growth factor gene transfer selectively modulates articular chondrocyte proliferation and matrix synthesis. We tested the hypothesis by delivering combinations of the transgenes encoding insulin-like growth factor I (IGF-I), fibroblast growth factor-2 (FGF-2), transforming growth factor beta1 (TGF-β1), bone morphogenetic protein-2 (BMP-2), and bone morphogenetic protien-7 (BMP-7) to articular chondrocytes and measured changes in the production of DNA, glycosaminoglycan, and collagen. The transgenes differentially regulated all these chondrocyte activities. In concert, the transgenes interacted to generate widely divergent responses from the cells. These interactions ranged from inhibitory to synergistic. The transgene pair encoding IGF-I and FGF-2 maximized cell proliferation. The three-transgene group encoding IGF-I, BMP-2, and BMP-7 maximized matrix production and also optimized the balance between cell proliferation and matrix production. These data demonstrate an approach to articular chondrocyte regulation that may be tailored to stimulate specific cell functions, and suggest that certain growth factor gene combinations have potential value for cell-based articular cartilage repair.

  11. Multiple biological activities for two peptides derived from the nerve growth factor precursor

    SciTech Connect

    Dicou, Eleni . E-mail: dicou@ipmc.cnrs.fr

    2006-09-01

    ProNGF can be cleaved proteolytically at dibasic residues and liberates two other peptides beside NGF, LIP1 a 29 amino acid (aa) peptide and LIP2 a 38 aa peptide. These peptides were found present in the rat intestine and shown to induce rapid phosphorylation of the Trk receptor in cell lines. The present study describes several novel biological properties for these peptides. They exert an anti-proliferative effect on the mitogenic activity of estrogen and IGF in MCF-7 cells. They protect against in vivo induction of excitotoxic lesions by the glutamatergic analogue ibotenate injected into the developing mouse brain and against in vitro NMDA-induced cell death in primary neuronal cultures. They bind to murine microglial cells and induce phosphorylation of Akt. These results suggest a role for LIP1 and LIP2 in cell survival.

  12. Plasminogen activator inhibitor 1: Mechanisms of its synergistic regulation by growth factors

    SciTech Connect

    Song, Xiaoling

    2010-01-01

    My research is on the synergistic regulation of PAI-1 by EGF and TGF-β. The mechanism of synergistic regulation of PAI-1 by EGF and TGF-β are addressed. Methods are described for effective identification of RNA accessible sites for antisense oligodexoxynucleotides (ODNs) and siRNA. In this study effective AS-ODN sequences for both Lcn2 and Bcl2 were identified by in vitro tiled microarray studies. Our results suggest that hybridization of ODN arrays to a target mRNA under physiological conditions might be used as a rapid and reliable in vitro method to accurately identify targets on mRNA molecules for effective antisense and potential siRNA activity in vivo.

  13. The mitogen-activated protein kinase cascade is activated by B-Raf in response to nerve growth factor through interaction with p21ras.

    PubMed Central

    Jaiswal, R K; Moodie, S A; Wolfman, A; Landreth, G E

    1994-01-01

    Nerve growth factor (NGF) activates the mitogen-activated protein (MAP) kinase cascade through a p21ras-dependent signal transduction pathway in PC12 cells. The linkage between p21ras and MEK1 was investigated to identify those elements which participate in the regulation of MEK1 activity. We have screened for MEK activators using a coupled assay in which the MAP kinase cascade has been reconstituted in vitro. We report that we have detected a single NGF-stimulated MEK-activating activity which has been identified as B-Raf. PC12 cells express both B-Raf and c-Raf1; however, the MEK-activating activity was found only in fractions containing B-Raf. c-Raf1-containing fractions did not exhibit a MEK-activating activity. Gel filtration analysis revealed that the B-Raf eluted with an apparent M(r) of 250,000 to 300,000, indicating that it is present within a stable complex with other unidentified proteins. Immunoprecipitation with B-Raf-specific antisera quantitatively precipitated all MEK activator activity from these fractions. We also demonstrate that B-Raf, as well as c-Raf1, directly interacted with activated p21ras immobilized on silica beads. NGF treatment of the cells had no effect on the ability of B-Raf or c-Raf1 to bind to activated p21ras. These data indicate that this interaction was not dependent upon the activation state of these enzymes; however, MEK kinase activity was found to be associated with p21ras following incubation with NGF-treated samples at levels higher than those obtained from unstimulated cells. These data provide direct evidence that NGF-stimulated B-Raf is responsible for the activation of the MAP kinase cascade in PC12 cells, whereas c-Raf1 activity was not found to function within this pathway. Images PMID:7935411

  14. RhoD activated by fibroblast growth factor induces cytoneme-like cellular protrusions through mDia3C

    PubMed Central

    Koizumi, Kazuhisa; Takano, Kazunori; Kaneyasu, Akiko; Watanabe-Takano, Haruko; Tokuda, Emi; Abe, Tomoyuki; Watanabe, Naoki; Takenawa, Tadaomi; Endo, Takeshi

    2012-01-01

    The small GTPase RhoD regulates actin cytoskeleton to collapse actin stress fibers and focal adhesions, resulting in suppression of cell migration and cytokinesis. It also induces alignment of early endosomes along actin filaments and reduces their motility. We show here that a constitutively activated RhoD generated two types of actin-containing thin peripheral cellular protrusions distinct from Cdc42-induced filopodia. One was longer, almost straight, immotile, and sensitive to fixation, whereas the other was shorter, undulating, motile, and resistant to fixation. Moreover, cells expressing wild-type RhoD extended protrusions toward fibroblast growth factor (FGF) 2/4/8–coated beads. Stimulation of wild-type RhoD-expressing cells with these FGFs also caused formation of cellular protrusions. Nodules moved through the RhoD-induced longer protrusions, mainly toward the cell body. Exogenously expressed FGF receptor was associated with these moving nodules containing endosome-like vesicles. These results suggest that the protrusions are responsible for intercellular communication mediated by FGF and its receptor. Accordingly, the protrusions are morphologically and functionally equivalent to cytonemes. RhoD was activated by FGF2/4/8. Knockdown of RhoD interfered with FGF-induced protrusion formation. Activated RhoD specifically bound to mDia3C and facilitated actin polymerization together with mDia3C. mDia3C was localized to the tips or stems of the protrusions. In addition, constitutively activated mDia3C formed protrusions without RhoD or FGF stimulation. Knockdown of mDia3 obstructed RhoD-induced protrusion formation. These results imply that RhoD activated by FGF signaling forms cytoneme-like protrusions through activation of mDia3C, which induces actin filament formation. PMID:23034183

  15. Novel diphenylamine 2,4'-dicarboxamide based azoles as potential epidermal growth factor receptor inhibitors: synthesis and biological activity.

    PubMed

    Abou-Seri, Sahar Mahmoud; Farag, Nahla Ahmed; Hassan, Ghaneya Sayed

    2011-01-01

    Several hybrid molecules of diphenylamine-2,4'-dicarboxamide with various azolidinones and related heterocyclic rings have been synthesized and explored as epidermal growth factor receptor (EGFR) kinase inhibitors. Most of them displayed promising in vitro tyrosine kinase inhibition as well as potent cellular antiproliferative activity in the EGFR over-expressing breast cancer cell line (MCF-7). Compounds 12b and 13b that exhibited the highest inhibition in the kinase assay (89, 81% inhibition at 10 μM, respectively), showed potent antiproliferative effect against MCF-7 tumor cell line (IC(50) 1.04, 0.91 μM respectively). Molecular docking studies revealed that these compounds can bind to ATP binding site of the EGFR kinase domain and were involved in H-bonding with Met 793, in analogy to the known EGFR tyrosine kinase inhibitors. Moreover, compounds 15a-c possessed profound antitumor activity (IC(50) 0.59-0.73 μM) and significant EGFR-TK inhibition, making them of particular interest. In summary, the newly synthesized compounds provide promising new lead for the future design and development of anticancer agents of potential EGFR-TK inhibitory activity.

  16. Fibroblast Growth Factor-9 Activates c-Kit Progenitor Cells and Enhances Angiogenesis in the Infarcted Diabetic Heart

    PubMed Central

    Singla, Dinender; Wang, Jing

    2016-01-01

    We hypothesized that fibroblast growth factor-9 (FGF-9) would enhance angiogenesis via activating c-kit positive stem cells in the infarcted nondiabetic and diabetic heart. In brief, animals were divided into three groups: Sham, MI, and MI+FGF-9. Two weeks following MI or sham surgery, our data suggest that treatment with FGF-9 significantly diminished vascular apoptosis compared to the MI group in both C57BL/6 and db/db mice (p < 0.05). Additionally, the number of c-kit+ve/SM α-actin+ve cells and c-kit+ve/CD31+ve cells were greatly enhanced in the MI+FGF-9 groups relative to the MI suggesting FGF-9 enhances c-Kit cell activation and their differentiation into vascular smooth muscle cells and endothelial cells, respectively (p < 0.05). Histology shows that the total number of vessels were quantified for all groups and our data suggest that the FGF-9 treated groups had significantly more vessels than their MI counterparts (p < 0.05). Finally, echocardiographic data suggests a significant improvement in left ventricular output, as indicated by fractional shortening and ejection fraction in both nondiabetic and diabetic animals treated with FGF-9 (p < 0.05). Overall, our data suggests FGF-9 has the potential to attenuate vascular cell apoptosis, activate c-Kit progenitor cells, and enhance angiogenesis and neovascularization in C57BL/6 and db/db mice leading to improved cardiac function. PMID:26682010

  17. Two Peptides Derived from the Nerve Growth Factor Precursor Are Biologically Active

    PubMed Central

    Dicou, Eleni; Pflug, Beth; Magazin, Marilyn; Lehy, Thérèse; Djakiew, Daniel; Ferrara, Pascual; Nerrière, Véronique; Harvie, Douglas

    1997-01-01

    This report provides evidence that the proregion of the NGF precursor protein contains two novel bioactive peptides. The presence of pairs of basic amino acid (aa) residues in the NGF proregion suggests that two or three peptides other than NGF may be generated by proteolytic cleavage. Synthetic peptides of 29 aa (LIP1) and 38aa (LIP2) corresponding to the sequences −71 to −43 and −40 to −3 of the proNGF, respectively, were used in this study. ELISA specific for these two peptides revealed their presence in the rat intestine. LIP1 was localized by immunohistochemistry in endocrine cells of the intestinal epithelium, and LIP2 was immunoprecipitated from an intestinal extract. We also provide evidence for the presence of specific receptors for LIP2 in several cell lines. Scatchard analysis indicated the presence of a low affinity binding site with a Kd of ∼10−7 M and a high affinity binding site of 10−9 M. Cross-linking studies revealed receptor forms of about 140 kD and 93 kD in a prostatic adenocarcinoma cell line. LIP1 and LIP2 induced rapid F-actin redistribution in PC12 cells within 2 min of incubation, which suggests a role of LIP1 and LIP2 in the process of neurite outgrowth. Furthermore, both propeptides induced rapid tyrosine phosphorylation of the Trk protein in both prostatic adenocarcinoma cells and PC12 cells, thus implicating trk in their mechanism of action. These results support our hypothesis that two peptides within the NGF precursor protein are biologically active. PMID:9015309

  18. Fluorogen activating protein-affibody probes: modular, no-wash measurement of epidermal growth factor receptors.

    PubMed

    Wang, Yi; Telmer, Cheryl A; Schmidt, Brigitte F; Franke, Josef D; Ort, Stephan; Arndt-Jovin, Donna J; Bruchez, Marcel P

    2015-01-21

    Fluorescence is essential for dynamic live cell imaging, and affinity reagents are required for quantification of endogenous proteins. Various fluorescent dyes can report on different aspects of biological trafficking, but must be independently conjugated to affinity reagents and characterized for specific biological readouts. Here we present the characterization of a new modular platform for small anti-EGFR affinity probes for studying rapid changes in receptor pools. A protein domain (FAP dL5**) that binds to malachite-green (MG) derivatives for fluorescence activation was expressed as a recombinant fusion to one or two copies of the compact EGFR binding affibody ZEGFR:1907. This is a recombinant and fluorogenic labeling reagent for native EGFR molecules. In vitro fluorescence assays demonstrated that the binding of these dyes to the FAP-affibody fusions produced thousand-fold fluorescence enhancements, with high binding affinity and fast association rates. Flow cytometry assays and fluorescence microscopy demonstrated that these probes label endogenous EGFR on A431 cells without disruption of EGFR function, and low nanomolar surface Kd values were observed with the double-ZEGFR:1907 constructs. The application of light-harvesting fluorogens (dyedrons) significantly improved the detected fluorescence signal. Altering the order of addition of the ligand, probe, and dyes allowed differentiation between surface and endocytotic pools of receptors to reveal the rapid dynamics of endocytic trafficking. Therefore, FAP/affibody coupling provides a new approach to construct compact and modular affinity probes that label endogenous proteins on living cells and can be used for studying rapid changes in receptor pools involved in trafficking. PMID:25490520

  19. Fluorogen Activating Protein–Affibody Probes: Modular, No-Wash Measurement of Epidermal Growth Factor Receptors

    PubMed Central

    2015-01-01

    Fluorescence is essential for dynamic live cell imaging, and affinity reagents are required for quantification of endogenous proteins. Various fluorescent dyes can report on different aspects of biological trafficking, but must be independently conjugated to affinity reagents and characterized for specific biological readouts. Here we present the characterization of a new modular platform for small anti-EGFR affinity probes for studying rapid changes in receptor pools. A protein domain (FAP dL5**) that binds to malachite-green (MG) derivatives for fluorescence activation was expressed as a recombinant fusion to one or two copies of the compact EGFR binding affibody ZEGFR:1907. This is a recombinant and fluorogenic labeling reagent for native EGFR molecules. In vitro fluorescence assays demonstrated that the binding of these dyes to the FAP–affibody fusions produced thousand-fold fluorescence enhancements, with high binding affinity and fast association rates. Flow cytometry assays and fluorescence microscopy demonstrated that these probes label endogenous EGFR on A431 cells without disruption of EGFR function, and low nanomolar surface Kd values were observed with the double-ZEGFR:1907 constructs. The application of light-harvesting fluorogens (dyedrons) significantly improved the detected fluorescence signal. Altering the order of addition of the ligand, probe, and dyes allowed differentiation between surface and endocytotic pools of receptors to reveal the rapid dynamics of endocytic trafficking. Therefore, FAP/affibody coupling provides a new approach to construct compact and modular affinity probes that label endogenous proteins on living cells and can be used for studying rapid changes in receptor pools involved in trafficking. PMID:25490520

  20. Growth factors from genes to clinical application

    SciTech Connect

    Sara, V.R. ); Hall, K.; Low, H. )

    1990-01-01

    The last decade has witnessed an explosion in the identification of growth factors and their receptors. This has been greatly facilitated by recombinant DNA technology, which has provided the tools not only to identify these proteins at the gene level but also to produce recombinant proteins for evaluating their biological activities. With the help of such techniques, we are moving toward an understanding of the biosynthesis of growth factors and their receptors, structure-function relationships, as well as mechanisms for intracellular signal transmission. The possibility of modifying these factors has opened new fields of clinical application. In this paper, four major areas of growth factor research are presented: the characterization of growth factor genes and their protein products, growth factor receptors and signal transduction by the receptors to mediate biological action, the biological actions of the various growth factors, and the role of growth factors in health and disease and their possible clinical application. Some of the topics covered include: structure of the IGFs and their variants; isoforms of PDGF receptor types; tyrosine kinase activation; structure of G-proteins in biological membranes; possible therapeutic application of NGF in the treatment of Parkinson's and Alzheimer's diseases; PDGF's possible role in the development of several fibroproliferative diseases and its therapeutic application in wound healing; and the possible use of angiogenic inhibitors in tumor treatment.

  1. The use of growth factors to modulate the activities of antigen–specific CD8+ T cells in vitro

    PubMed Central

    Alenzi, FQ; Alenazi, FA; Al-Kaabi, Y; Salem, ML

    2011-01-01

    Rationale: Adoptive T cell therapy depends on the harvesting of the cells from the host, their activation in vitro, and their infusion back to the same host. The way of activating the T cells in vitro is a critical factor for their homing, survival and function in vivo. Sustaining T cell homing molecules, particularly CD62L, is benefic for the trafficking of the adoptive transferred cells. Objective: The aim of the present study is to test whether insulin–like growth factor–1 (IGF–1), thymosin– α1 (T–α1) as well as all–trans retinoid acid (ATRA) alone or in combination with IL–2, IL–12, IL–15 can enhance the activation and survival phenotypes of antigen-activated T cells in vitro. Methods & Results: To this end, OT–1 transgenic T cells were used as a model. These CD8+ T cells recognize OVA peptide presented by MHC class–I. The results showed that antigen stimulation of OT1 cells resulted in their activation as evidenced by the decrease in surface expression of CD62L, analyzed for 3 days after antigen stimulation and was more pronounced on day 5. The addition of IL–12 or IGF–1 alone but not of IL–2, IL–15 augmented OT–1 cell activation measured on day 5. Interestingly, the combination of IL–12 with IGF–1 sustained the expression of CD62L on OT1 cells. Although the addition of ATRA alone or in combination with IL–12 resulted in decreases in CD62L expression on day 3, they showed a dose–dependent effect on the restoration of CD62L expression on day 5. The analysis of the activation–induced cell death (apoptosis) of OT1 cells showed an increased rate of death on day 5 than on day 3–post antigen stimulation. The addition of only IL–12 or IGF–1 alone, but not of IL–2, IL–15 or T– α1, decreased OT1 cell apoptosis on day 3. These anti–apoptotic effects of IL–12 and IGF– 1, however, were recovered on day 5–post stimulation. Discussion: In conclusion, these results indicate that the activation phenotype and the

  2. Effect of exogenous insulin on plasma and follicular insulin-like growth factor I, insulin-like growth factor binding protein activity, follicular oestradiol and progesterone, and follicular growth in superovulated Angus and Brahman cows.

    PubMed

    Simpson, R B; Chase, C C; Spicer, L J; Vernon, R K; Hammond, A C; Rae, D O

    1994-11-01

    Angus (n = 14) and Brahman (n = 14) cows were used to evaluate the effects of insulin administered concomitantly with FSH in a superovulation regimen. Cows were allotted to four pen replicates by treatment and breed, and received FSH (i.m.) twice a day for 5 consecutive days (first day of injections = day 0 of study) plus concomitant administration of either saline (control) or long-acting bovine insulin (0.25 iu kg-1 body mass; s.c.). Blood samples were collected at intervals of 6 h during the injection period and analysed for plasma insulin, glucose, insulin-like growth factor I (IGF-I) and IGF-I binding protein (IGFBP) activity. Cows were ovariectomized on day 5. The number and diameter of follicles were recorded. Follicular fluid was aspirated for determination of IGF-I, IGFBP activity, oestradiol and progesterone. Mean plasma concentration of glucose was lower in insulin-treated than in control cows averaged over days 1-5 (56 +/- 3 versus 82 +/- 3 mg dl-1; P < 0.01). Plasma concentration of IGF-I and IGFBP activity were not affected (P > 0.10) by treatment, but were higher in Brahman than in Angus cows (IGF-I: 41 +/- 6 versus 19 +/- 6 ng ml-1, P < 0.05; IGFBP activity: 17.5 +/- 0.4 versus 15.8 +/- 0.04% (10 microliters)-1; P < 0.03). Insulin treatment did not affect the number of small (1.0-3.9 mm), medium (4.0-7.9 mm) or large (> or = 8.0 mm) follicles. Brahman cows had a greater (P < 0.01) number of medium and total follicles (19.4 +/- 2.5 and 60.5 +/- 5.5, respectively) than did Angus cows (7.5 +/- 2.6 and 30.5 +/- 5.6, respectively). Diameter of large follicles was greater in insulin-treated than in control cows (11.4 +/- 0.2 versus 10.6 +/- 0.1 mm; P < 0.05). Follicular fluid IGF-I concentration in large follicles was higher in insulin-treated Brahman cows (60 +/- 2 ng ml-1) than in control Brahman cows (37 +/- 2 ng ml-1), but was lower in insulin-treated Angus cows (31 +/- 3 ng ml-1) than in control Angus cows (38 +/- 2 ng ml-1; treatment x breed

  3. Vascular smooth muscle cells from injured rat aortas display elevated matrix production associated with transforming growth factor-beta activity.

    PubMed Central

    Rasmussen, L. M.; Wolf, Y. G.; Ruoslahti, E.

    1995-01-01

    The arterial response to injury is characterized by a short period of increased proliferation and migration of vascular smooth muscle cells, followed by an extended period of extracellular matrix accumulation in the intima. Transforming growth factor-beta (TGF-beta) has been implicated as a causative factor in the formation of extracellular matrix in this process, which leads to progressive thickening of the intima, known as intimal hyperplasia. In vitro analysis of vascular smooth muscle cells harvested from normal rat aortas and from aortas injured 14 days earlier showed that both types of cells attached equally well to culture dishes but that the initial spreading of the cells was increased in cells derived from injured vessels. Cells from the injured arteries produced more fibronectin and proteoglycans into the culture medium than the cells from normal arteries and contained more TGF-beta 1 mRNA. TGF-beta 1 increased proteoglycan synthesis by normal smooth muscle cells, and the presence of a neutralizing anti-TGF-beta 1 antibody reduced proteoglycan synthesis by the cells from injured arteries in culture. Fibronectin synthesis was not altered by these treatments. These results indicate that the accumulation of extracellular matrix components in neointimal lesions is at least partially caused by autocrine TGF-beta activity in vascular smooth muscle cells. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 PMID:7573349

  4. Main factors controlling microbial community structure, growth and activity after reclamation of a tailing pond with aided phytostabilization

    NASA Astrophysics Data System (ADS)

    Zornoza, Raúl; Acosta, José A.; Martínez-Martínez, Silvia; Faz, Ángel; Bååth, Erland

    2015-04-01

    Reclamation on bare tailing ponds has the potential to represent soil genesis in Technosols favoring the understanding of the changes of microbial communities and function. In this study we used phytostabilization aided with calcium carbonate and pig slurry/manure to reclaim an acidic bare tailing pond with the aim of investigating the effect of amending and different species on microbial community structure and function. We sampled after two years of amending and planting: unamended tailing soil (UTS), non-rhizospheric amended tailing soil (ATS), rhizospheric soil from four species, and non-rhizospheric native forest soil (NS), which acted as reference. The application of amendments increased pH up to neutrality, organic carbon (Corg), C/N and aggregate stability, while decreased salinity and heavy metals availability. No effect of rhizosphere was observed on physicochemical properties, metals immobilization and microbial community structure and function. To account for confounding effects due to soil organic matter, microbial properties were expressed per Corg. The high increments in pH and Corg have been the main factors driving changes in microbial community structure and function. Bacterial biomass was higher in UTS, without significant differences among the rest of soils. Fungal biomass followed the trend UTS < ATS = rhizospheric soils < NS. Bacterial growth increased and fungal growth decreased with increasing pH, despite the high availability of metals at low pH. Enzyme activities were lower in UTS, being β-glucosidase and β-glucosaminidase activities highly correlated with bacterial growth. Microbial activities were not correlated with the exchangeable fraction of heavy metals, indicating that microbial function is not strongly affected by these metals, likely due to the efficiency of the reclamation procedure to reduce metals toxicity. Changes in microbial community composition were largely explained by changes in pH, heavy metals availability and Corg

  5. Transforming growth factor-beta1-induced activation of the Raf-MEK-MAPK signaling pathway in rat lung fibroblasts via a PKC-dependent mechanism.

    PubMed

    Axmann, A; Seidel, D; Reimann, T; Hempel, U; Wenzel, K W

    1998-08-19

    In fibroblasts transforming growth factor-beta1 (TGF-beta1) regulates cell proliferation and turnover of macromolecular components of the extracellular matrix. Here, intracellular signaling events in growth-inhibited embryonic rat lung fibroblasts (RFL-6) upon stimulation with TGF-beta1 were investigated. TGF-beta1 rapidly induced the activation of c-Raf-1, MEK-1, and MAPK p42 and p44. The activation of this pathway by TGF-beta1 did not depend on autocrine platelet-derived growth factor (PDGF) or basic fibroblast growth factor (bFGF). Inhibition of the binding of growth factors to their tyrosine kinase receptors did not affect MAPK activation by TGF-beta1. Ras activation by TGF-beta1 was significantly lower compared to the activation by PDGF or bFGF. The intracellular transduction of the TGF-beta1 signal was completely suppressed by depletion or inhibition of protein kinase C (PKC). It is shown that calcium-dependent isoforms of PKC are required for MAPK activation by TGF-beta1. PMID:9712718

  6. Neuroligin-1 induces neurite outgrowth through interaction with neurexin-1β and activation of fibroblast growth factor receptor-1.

    PubMed

    Gjørlund, Michelle D; Nielsen, Janne; Pankratova, Stanislava; Li, Shizhong; Korshunova, Irina; Bock, Elisabeth; Berezin, Vladimir

    2012-10-01

    Neurexin-1 (NRXN1) and neuroligin-1 (NLGN1) are synaptic cell adhesion molecules that connect pre- and postsynaptic neurons at synapses and mediate signaling across the synapse, which modulates synaptic activity and determines the properties of neuronal networks. Defects in the genes encoding NLGN1 have been linked to cognitive diseases such as autism. The roles of both NRXN1 and NLGN1 during synaptogenesis have been studied extensively, but little is known about the role of these molecules in neuritogenesis, which eventually results in neuronal circuitry formation. The present study investigated the neuritogenic effect of NLGN1 in cultures of hippocampal neurons. Our results show that NLGN1, both in soluble and membrane-bound forms, induces neurite outgrowth that depends on the interaction with NRXN1β and on activation of fibroblast growth factor receptor-1. In addition, we demonstrate that a synthetic peptide, termed neurolide, which is modeled after a part of the binding interface of NLGN1 for NRXN1β, can bind to NRXN1β and mimic the biological properties of NLGN1 in vitro.

  7. Sensitivity and kinase activity of epidermal growth factor receptor (EGFR) exon 19 and others to EGFR-tyrosine kinase inhibitors.

    PubMed

    Furuyama, Kazuto; Harada, Taishi; Iwama, Eiji; Shiraishi, Yoshimasa; Okamura, Kyoko; Ijichi, Kayo; Fujii, Akiko; Ota, Keiichi; Wang, Shuo; Li, Heyan; Takayama, Koichi; Giaccone, Giuseppe; Nakanishi, Yoichi

    2013-05-01

    The presence of epidermal growth factor receptor (EGFR) somatic mutations in non-small-cell lung cancer patients is associated with response to treatment with EGFR-tyrosine kinase inhibitors, such as gefitinib and erlotinib. More than 100 mutations in the kinase domain of EGFR have been identified. In particular there are many variations of deletion mutations in exon 19. In this study, using yellow fluorescent protein-tagged fragments of the EGFR intracellular domain, we examined the differences in sensitivity to gefitinib, erlotinib and afatinib between several exon 19 mutants and other common EGFR mutations. We also used serum of patients undergoing treatment with EGFR-tyrosine kinase inhibitors in this system. In addition, we examined the relative kinase activity of these mutants by measuring relative fluorescent intensity after immunofluorescence staining. We found that both sensitivity to EGFR-tyrosine kinase inhibitors and relative kinase activity differed among several EGFR mutations found in the same region of the kinase domain. This study underscores the importance of reporting the clinical outcome of treatment in relation to different EGFR mutations.

  8. Active macropinocytosis induction by stimulation of epidermal growth factor receptor and oncogenic Ras expression potentiates cellular uptake efficacy of exosomes

    PubMed Central

    Nakase, Ikuhiko; Kobayashi, Nahoko Bailey; Takatani-Nakase, Tomoka; Yoshida, Tetsuhiko

    2015-01-01

    Exosomes are approximately 100-nm vesicles that consist of a lipid bilayer of cellular membranes secreted in large quantities from various types of normal and disease-related cells. Endocytosis has been reported as a major pathway for the cellular uptake of exosomes; however, the detailed mechanisms of their cellular uptake are still unknown. Here, we demonstrate the active induction of macropinocytosis (accompanied by actin reorganisation, ruffling of plasma membrane, and engulfment of large volumes of extracellular fluid) by stimulation of cancer-related receptors and show that the epidermal growth factor (EGF) receptor significantly enhances the cellular uptake of exosomes. We also demonstrate that oncogenic K-Ras-expressing MIA PaCa-2 cells exhibit intensive macropinocytosis that actively transports extracellular exosomes into the cells compared with wild-type K-Ras-expressing BxPC-3 cells. Furthermore, encapsulation of the ribosome-inactivating protein saporin with EGF in exosomes using our simple electroporation method produces superior cytotoxicity via the enhanced cellular uptake of exosomes. Our findings contribute to the biological, pharmaceutical, and medical research fields in terms of understanding the macropinocytosis-mediated cellular uptake of exosomes with applications for exosomal delivery systems. PMID:26036864

  9. Active macropinocytosis induction by stimulation of epidermal growth factor receptor and oncogenic Ras expression potentiates cellular uptake efficacy of exosomes.

    PubMed

    Nakase, Ikuhiko; Kobayashi, Nahoko Bailey; Takatani-Nakase, Tomoka; Yoshida, Tetsuhiko

    2015-06-03

    Exosomes are approximately 100-nm vesicles that consist of a lipid bilayer of cellular membranes secreted in large quantities from various types of normal and disease-related cells. Endocytosis has been reported as a major pathway for the cellular uptake of exosomes; however, the detailed mechanisms of their cellular uptake are still unknown. Here, we demonstrate the active induction of macropinocytosis (accompanied by actin reorganisation, ruffling of plasma membrane, and engulfment of large volumes of extracellular fluid) by stimulation of cancer-related receptors and show that the epidermal growth factor (EGF) receptor significantly enhances the cellular uptake of exosomes. We also demonstrate that oncogenic K-Ras-expressing MIA PaCa-2 cells exhibit intensive macropinocytosis that actively transports extracellular exosomes into the cells compared with wild-type K-Ras-expressing BxPC-3 cells. Furthermore, encapsulation of the ribosome-inactivating protein saporin with EGF in exosomes using our simple electroporation method produces superior cytotoxicity via the enhanced cellular uptake of exosomes. Our findings contribute to the biological, pharmaceutical, and medical research fields in terms of understanding the macropinocytosis-mediated cellular uptake of exosomes with applications for exosomal delivery systems.

  10. Helicobacter pylori culture supernatant interferes with epidermal growth factor-activated signal transduction in human gastric KATO III cells.

    PubMed Central

    Pai, R.; Wyle, F. A.; Cover, T. L.; Itani, R. M.; Domek, M. J.; Tarnawski, A. S.

    1998-01-01

    The mechanisms by which Helicobacter pylori infection leads to gastroduodenal ulceration remain poorly understood. Previous studies have shown that H. pylori vacuolating cytotoxin (VacA) inhibits proliferation of gastric epithelial cells, which suggests that H pylori may interfere with gastric mucosal repair mechanisms. In this study, we investigated the effects of H. pylori broth culture supernatants on epidermal growth factor (EGF)-mediated signal transduction pathways in a gastric carcinoma cell line (KATO III). Exposure of these cells to EGF resulted in increased expression and phosphorylation of the EGF receptor (EGF-R), increased ERK2 activity and phosphorylation, and increased c-fos protein levels. Preincubation of cells with broth culture supernatant from VacA (+) H. pylori strain 60190 inhibited the capacity of EGF to induce each of these effects. In contrast, preincubation of cells with broth culture supernatant from an isogenic VacA-mutant strain (H. pylori 60190-v1) failed to inhibit the effects of EGF. These results suggest that the H. pylori vacuolating cytotoxin interferes with EGF-activated signal transduction pathways, which are known to be essential for cell proliferation and ulcer healing. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:9626065

  11. Helicobacter pylori culture supernatant interferes with epidermal growth factor-activated signal transduction in human gastric KATO III cells.

    PubMed

    Pai, R; Wyle, F A; Cover, T L; Itani, R M; Domek, M J; Tarnawski, A S

    1998-06-01

    The mechanisms by which Helicobacter pylori infection leads to gastroduodenal ulceration remain poorly understood. Previous studies have shown that H. pylori vacuolating cytotoxin (VacA) inhibits proliferation of gastric epithelial cells, which suggests that H pylori may interfere with gastric mucosal repair mechanisms. In this study, we investigated the effects of H. pylori broth culture supernatants on epidermal growth factor (EGF)-mediated signal transduction pathways in a gastric carcinoma cell line (KATO III). Exposure of these cells to EGF resulted in increased expression and phosphorylation of the EGF receptor (EGF-R), increased ERK2 activity and phosphorylation, and increased c-fos protein levels. Preincubation of cells with broth culture supernatant from VacA (+) H. pylori strain 60190 inhibited the capacity of EGF to induce each of these effects. In contrast, preincubation of cells with broth culture supernatant from an isogenic VacA-mutant strain (H. pylori 60190-v1) failed to inhibit the effects of EGF. These results suggest that the H. pylori vacuolating cytotoxin interferes with EGF-activated signal transduction pathways, which are known to be essential for cell proliferation and ulcer healing. PMID:9626065

  12. Upregulation of early growth response factor-1 by bile acids requires mitogen-activated protein kinase signaling

    SciTech Connect

    Allen, Katryn; Kim, Nam Deuk; Moon, Jeon-OK; Copple, Bryan L.

    2010-02-15

    Cholestasis results when excretion of bile acids from the liver is interrupted. Liver injury occurs during cholestasis, and recent studies showed that inflammation is required for injury. Our previous studies demonstrated that early growth response factor-1 (Egr-1) is required for development of inflammation in liver during cholestasis, and that bile acids upregulate Egr-1 in hepatocytes. What remains unclear is the mechanism by which bile acids upregulate Egr-1. Bile acids modulate gene expression in hepatocytes by activating the farnesoid X receptor (FXR) and through activation of mitogen-activated protein kinase (MAPK) signaling. Accordingly, the hypothesis was tested that bile acids upregulate Egr-1 in hepatocytes by FXR and/or MAPK-dependent mechanisms. Deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA) stimulated upregulation of Egr-1 to the same extent in hepatocytes isolated from wild-type mice and FXR knockout mice. Similarly, upregulation of Egr-1 in the livers of bile duct-ligated (BDL) wild-type and FXR knockout mice was not different. Upregulation of Egr-1 in hepatocytes by DCA and CDCA was prevented by the MEK inhibitors U0126 and SL-327. Furthermore, pretreatment of mice with U0126 prevented upregulation of Egr-1 in the liver after BDL. Results from these studies demonstrate that activation of MAPK signaling is required for upregulation of Egr-1 by bile acids in hepatocytes and for upregulation of Egr-1 in the liver during cholestasis. These studies suggest that inhibition of MAPK signaling may be a novel therapy to prevent upregulation of Egr-1 in liver during cholestasis.

  13. Vascular endothelial growth factor signaling regulates the segregation of artery and vein via ERK activity during vascular development

    SciTech Connect

    Kim, Se-Hee; Schmitt, Christopher E.; Woolls, Melissa J.; Holland, Melinda B.; Kim, Jun-Dae; Jin, Suk-Won

    2013-01-25

    Highlights: ► VEGF-A signaling regulates the segregation of axial vessels. ► VEGF-A signaling is mediated by PKC and ERK in this process. ► Ectopic activation of ERK is sufficient to rescue defects in vessel segregation. -- Abstract: Segregation of two axial vessels, the dorsal aorta and caudal vein, is one of the earliest patterning events occur during development of vasculature. Despite the importance of this process and recent advances in our understanding on vascular patterning during development, molecular mechanisms that coordinate the segregation of axial vessels remain largely elusive. In this report, we find that vascular endothelial growth factor-A (Vegf-A) signaling regulates the segregation of dorsal aorta and axial vein during development. Inhibition of Vegf-A pathway components including ligand Vegf-A and its cognate receptor Kdrl, caused failure in segregation of axial vessels in zebrafish embryos. Similarly, chemical inhibition of Mitogen-activated protein kinase kinase (Map2k1)/Extracellular-signal-regulated kinases (Erk) and phosphatidylinositol 3-kinases (PI3 K), which are downstream effectors of Vegf-A signaling pathway, led to the fusion of two axial vessels. Moreover, we find that restoring Erk activity by over-expression of constitutively active MEK in embryos with a reduced level of Vegf-A signaling can rescue the defects in axial vessel segregation. Taken together, our data show that segregation of axial vessels requires the function of Vegf-A signaling, and Erk may function as the major downstream effector in this process.

  14. Specific activation of insulin-like growth factor-1 receptor by ginsenoside Rg5 promotes angiogenesis and vasorelaxation.

    PubMed

    Cho, Young-Lai; Hur, Sung-Mo; Kim, Ji-Yoon; Kim, Ji-Hee; Lee, Dong-Keon; Choe, Jongeon; Won, Moo-Ho; Ha, Kwon-Soo; Jeoung, Dooil; Han, Sanghwa; Ryoo, Sungwoo; Lee, Hansoo; Min, Jeong-Ki; Kwon, Young-Guen; Kim, Dong-Hyun; Kim, Young-Myeong

    2015-01-01

    Ginsenoside Rg5 is a compound newly synthesized during the steaming process of ginseng; however, its biological activity has not been elucidated with regard to endothelial function. We found that Rg5 stimulated in vitro angiogenesis of human endothelial cells, consistent with increased neovascularization and blood perfusion in a mouse hind limb ischemia model. Rg5 also evoked vasorelaxation in aortic rings isolated from wild type and high cholesterol-fed ApoE(-/-) mice but not from endothelial nitric-oxide synthase (eNOS) knock-out mice. Angiogenic activity of Rg5 was highly associated with a specific increase in insulin-like growth factor-1 receptor (IGF-1R) phosphorylation and subsequent activation of multiple angiogenic signals, including ERK, FAK, Akt/eNOS/NO, and Gi-mediated phospholipase C/Ca(2+)/eNOS dimerization pathways. The vasodilative activity of Rg5 was mediated by the eNOS/NO/cGMP axis. IGF-1R knockdown suppressed Rg5-induced angiogenesis and vasorelaxation by inhibiting key angiogenic signaling and NO/cGMP pathways. In silico docking analysis showed that Rg5 bound with high affinity to IGF-1R at the same binding site of IGF. Rg5 blocked binding of IGF-1 to its receptor with an IC50 of ∼90 nmol/liter. However, Rg5 did not induce vascular inflammation and permeability. These data suggest that Rg5 plays a novel role as an IGF-1R agonist, promoting therapeutic angiogenesis and improving hypertension without adverse effects in the vasculature. PMID:25391655

  15. Fibroblast growth factor 2 dimer with superagonist in vitro activity improves granulation tissue formation during wound healing.

    PubMed

    Decker, Caitlin G; Wang, Yu; Paluck, Samantha J; Shen, Lu; Loo, Joseph A; Levine, Alex J; Miller, Lloyd S; Maynard, Heather D

    2016-03-01

    Site-specific chemical dimerization of fibroblast growth factor 2 (FGF2) with the optimal linker length resulted in a FGF2 homodimer with improved granulation tissue formation and blood vessel formation at exceptionally low concentrations. Homodimers of FGF2 were synthesized through site-specific linkages to both ends of different molecular weight poly(ethylene glycols) (PEGs). The optimal linker length was determined by screening dimer-induced metabolic activity of human dermal fibroblasts and found to be that closest to the inter-cysteine distance, 70 Å, corresponding to 2 kDa PEG. A straightforward analysis of the kinetics of second ligand binding as a function of tether length showed that, as the polymerization index (the number of monomer repeat units in the polymer, N) of the tether decreases, the mean time for second ligand capture decreases as ∼N(3/2), leading to an enhancement of the number of doubly bound ligands in steady-state for a given (tethered) ligand concentration. FGF2-PEG2k-FGF2 induced greater fibroblast metabolic activity than FGF2 alone, all other dimers, and all monoconjugates, at each concentration tested, with the greatest difference observed at low (0.1 ng/mL) concentration. FGF2-PEG2k-FGF2 further exhibited superior activity compared to FGF2 for both metabolic activity and migration in human umbilical vein endothelial cells, as well as improved angiogenesis in a coculture model in vitro. Efficacy in an in vivo wound healing model was assessed in diabetic mice. FGF2-PEG2k-FGF2 increased granulation tissue and blood vessel density in the wound bed compared to FGF2. The results suggest that this rationally designed construct may be useful for improving the fibroblast matrix formation and angiogenesis in chronic wound healing.

  16. Specific Activation of Insulin-like Growth Factor-1 Receptor by Ginsenoside Rg5 Promotes Angiogenesis and Vasorelaxation*

    PubMed Central

    Cho, Young-Lai; Hur, Sung-Mo; Kim, Ji-Yoon; Kim, Ji-Hee; Lee, Dong-Keon; Choe, Jongeon; Won, Moo-Ho; Ha, Kwon-Soo; Jeoung, Dooil; Han, Sanghwa; Ryoo, Sungwoo; Lee, Hansoo; Min, Jeong-Ki; Kwon, Young-Guen; Kim, Dong-Hyun; Kim, Young-Myeong

    2015-01-01

    Ginsenoside Rg5 is a compound newly synthesized during the steaming process of ginseng; however, its biological activity has not been elucidated with regard to endothelial function. We found that Rg5 stimulated in vitro angiogenesis of human endothelial cells, consistent with increased neovascularization and blood perfusion in a mouse hind limb ischemia model. Rg5 also evoked vasorelaxation in aortic rings isolated from wild type and high cholesterol-fed ApoE−/− mice but not from endothelial nitric-oxide synthase (eNOS) knock-out mice. Angiogenic activity of Rg5 was highly associated with a specific increase in insulin-like growth factor-1 receptor (IGF-1R) phosphorylation and subsequent activation of multiple angiogenic signals, including ERK, FAK, Akt/eNOS/NO, and Gi-mediated phospholipase C/Ca2+/eNOS dimerization pathways. The vasodilative activity of Rg5 was mediated by the eNOS/NO/cGMP axis. IGF-1R knockdown suppressed Rg5-induced angiogenesis and vasorelaxation by inhibiting key angiogenic signaling and NO/cGMP pathways. In silico docking analysis showed that Rg5 bound with high affinity to IGF-1R at the same binding site of IGF. Rg5 blocked binding of IGF-1 to its receptor with an IC50 of ∼90 nmol/liter. However, Rg5 did not induce vascular inflammation and permeability. These data suggest that Rg5 plays a novel role as an IGF-1R agonist, promoting therapeutic angiogenesis and improving hypertension without adverse effects in the vasculature. PMID:25391655

  17. Latent transforming growth factor beta1 activation in situ: quantitative and functional evidence after low-dose gamma-irradiation

    NASA Technical Reports Server (NTRS)

    Ehrhart, E. J.; Segarini, P.; Tsang, M. L.; Carroll, A. G.; Barcellos-Hoff, M. H.; Chatterjee, A. (Principal Investigator)

    1997-01-01

    The biological activity of transforming growth factor beta1 (TGF-beta) is controlled by its secretion as a latent complex in which it is noncovalently associated with latency-associated peptide (LAP). Activation is the extracellular process in which TGF-beta is released from LAP, and is considered to be a primary regulatory control. We recently reported rapid and persistent changes in TGF-beta immunoreactivity in conjunction with extracellular matrix remodeling in gamma-irradiated mouse mammary gland. Our hypothesis is that these specific changes in immunoreactivity are indicative of latent TGF-beta activation. In the present study, we determined the radiation dose response and tested whether a functional relationship exists between radiation-induced TGF-beta and collagen type III remodeling. After radiation exposures as low as 0.1 Gy, we detected increased TGF-beta immunoreactivity in the mammary epithelium concomitant with decreased LAP immunostaining, which are events consistent with activation. Quantitative image analysis demonstrated a significant (P=0.0005) response at 0.1 Gy without an apparent threshold and a linear dose response to 5 Gy. However, in the adipose stroma, loss of LAP demonstrated a qualitative threshold at 0.5 Gy. Loss of LAP paralleled induction of collagen III immunoreactivity in this tissue compartment. We tested whether TGF-beta mediates collagen III expression by treating animals with TGF-beta panspecific monoclonal antibody, 1D11.16, administered i.p. shortly before irradiation. Radiation-induced collagen III staining in the adipose stroma was blocked in an antibody dose-dependent manner, which persisted through 7 days postirradiation. RNase protection assay revealed that radiation-induced elevation of total gland collagen III mRNA was also blocked by neutralizing antibody treatment. These data provide functional confirmation of the hypothesis that radiation exposure leads to latent TGF-beta activation, support our interpretation of the

  18. Functional and structural characterization of P40, a mouse glycoprotein with T-cell growth factor activity.

    PubMed Central

    Uyttenhove, C; Simpson, R J; Van Snick, J

    1988-01-01

    Antigen-independent cell lines were derived from mouse helper T-cell clones by culture in autologous supernatant obtained after stimulation with concanavalin A. A factor, termed P40, supporting the growth of these lines was purified and characterized as a basic 32- to 39-kDa single-chain glycoprotein functionally distinct from previously identified T-cell growth factors and apparently unrelated structurally to any known protein. Of a number of cell lines, only helper T cells responded to P40, and this response was not mediated by either interleukin 2 or interleukin 4. Images PMID:3137580

  19. Activated Protein C Enhances Human Keratinocyte Barrier Integrity via Sequential Activation of Epidermal Growth Factor Receptor and Tie2*

    PubMed Central

    Xue, Meilang; Chow, Shu-Oi; Dervish, Suat; Chan, Yee-Ka Agnes; Julovi, Sohel M.; Jackson, Christopher J.

    2011-01-01

    Keratinocytes play a critical role in maintaining epidermal barrier function. Activated protein C (APC), a natural anticoagulant with anti-inflammatory and endothelial barrier protective properties, significantly increased the barrier impedance of keratinocyte monolayers, measured by electric cell substrate impedance sensing and FITC-dextran flux. In response to APC, Tie2, a tyrosine kinase receptor, was rapidly activated within 30 min, and relocated to cell-cell contacts. APC also increased junction proteins zona occludens, claudin-1 and VE-cadherin. Inhibition of Tie2 by its peptide inhibitor or small interfering RNA abolished the barrier protective effect of APC. Interestingly, APC did not activate Tie2 through its major ligand, angiopoietin-1, but instead acted by binding to endothelial protein C receptor, cleaving protease-activated receptor-1 and transactivating EGF receptor. Furthermore, when activation of Akt, but not ERK, was inhibited, the barrier protective effect of APC on keratinocytes was abolished. Thus, APC activates Tie2, via a mechanism requiring, in sequential order, the receptors, endothelial protein C receptor, protease-activated receptor-1, and EGF receptor, which selectively enhances the PI3K/Akt signaling to enhance junctional complexes and reduce keratinocyte permeability. PMID:21173154

  20. Nerve growth factor-mediated inhibition of apoptosis post-caspase activation is due to removal of active caspase-3 in a lysosome-dependent manner

    PubMed Central

    Mnich, K; Carleton, L A; Kavanagh, E T; Doyle, K M; Samali, A; Gorman, A M

    2014-01-01

    Nerve growth factor (NGF) is well characterised as an important pro-survival factor in neuronal cells that can inhibit apoptotic cell death upstream of mitochondrial outer membrane permeabilisation. Here we addressed the question of whether NGF can also protect against apoptosis downstream of caspase activation. NGF treatment promoted a rapid reduction in the level of the p17 subunit of active caspase-3 in PC12 cells that had been induced to undergo apoptosis by various cytotoxins. The mechanism involved TrkA-dependent activation of extracellular signal-regulated kinase (ERK1/2) but not phosphatidylinositol 3-kinase (PI3K)/Akt, and de novo protein synthesis. Involvement of inhibitor of apoptosis proteins (IAPs) and proteasomal degradation were ruled out. In contrast, inhibition of lysosome function using chloroquine and concanamycin A reversed NGF-induced removal of p17. Moreover, in NGF-treated cells, active caspases were found to be localised to lysosomes. The involvement of macroautophagy and chaperone-mediated autophagy were ruled out. Taken together, these findings suggest an anti-apoptotic mechanism by which NGF induces removal of active caspase-3 in a lysosome-dependent manner. PMID:24787014

  1. Suppression of growth factor-mediated MAP kinase activation by v-raf in macrophages: a putative role for the MKP-1 phosphatase.

    PubMed

    Krautwald, S; Büscher, D; Dent, P; Ruthenberg, K; Baccarini, M

    1995-03-16

    Many tyrosine kinase growth factor receptors activate the MAP Kinase (MAPK) pathway by stimulating the activity of the RAF kinase. In some, but not all cell types, the expression of activated RAF is sufficient to induce constitutive MAPK activation. In BAC-1.2F5 macrophages the expression of virally activated RAF does not correlate with constitutive MAPK activation; on the contrary, growth factor-mediated stimulation of MAPK activity is suppressed in these cells. Suppression correlates with v-RAF expression, as MAPK activation is normal in a revertant cell line that stopped expressing v-RAF. Inhibition of MAPK activation is associated with lack of ERK-2 tyrosine phosphorylation, and is not due to the suppression of CSF-1-mediated MEK activation. Pretreatment with vanadate restores growth factor-stimulated activation and tyrosine phosphorylation of MAPK in v-RAF-expressing macrophages, indicating the involvement of a tyrosine phosphatase. Interestingly, v-RAF-expressing macrophages contain low constitutive levels of MKP-1 mRNA, an immediate early gene that encodes a MAPK-specific phosphatase and is induced in the parental cell line by CSF-1 treatment. The restoration of MAPK activation by vanadate pretreatment and the presence of MKP-1 mRNA in v-RAF-expressing macrophages raise the intriguing possibility that in macrophages RAF may be feeding back on the MAPK pathway by participating in the control of MKP-1 expression. PMID:7700643

  2. Mycobacterium tuberculosis RNA Expression Patterns in Sputum Bacteria Indicate Secreted Esx Factors Contributing to Growth are Highly Expressed in Active Disease

    PubMed Central

    Bukka, Archana; Price, Christopher T. D.; Kernodle, Douglas S.; Graham, James E.

    2012-01-01

    To identify factors contributing to the ability of tubercle bacilli to grow in the lung during active infection, we analyzed RNA expression patterns in bacteria present in patient sputum. Prominent among bacterial transcripts identified were those encoding secreted peptides of the Esat-6 subfamily that includes EsxK and EsxL (Rv1197 and Rv1198). H37Rv esxKL and esxJI transcripts were differentially expressed under different growth conditions, and disruption of these genes altered growth phase kinetics in typical laboratory batch broth cultures. These growth defects, including the reduced intracellular growth of an ΔesxKL mutant in primary human macrophages, were reversed by either low multiplicity co-infection or co-culture with wild-type bacteria, demonstrating the ability of the secreted factors to rescue isogenic mutants. Complementing either only esxL or esxI alone (Rv1198 or Rv1037c) also reduced observed growth defects, indicating these genes encode factors capable of contributing to growth. Our studies indicate that the Mycobacterium tuberculosis Mtb9.9 family secreted factors EsxL and EsxI can act in trans to modulate growth of intracellular bacteria, and are highly expressed during active human lung infection. PMID:22291682

  3. In Vivo Regulation of Brain-Derived Neurotrophic Factor in Dorsal Root Ganglia Is Mediated by Nerve Growth Factor-Triggered Akt Activation during Cystitis

    PubMed Central

    Qiao, Li-Ya; Yu, Sharon J.; Kay, Jarren C.; Xia, Chun-Mei

    2013-01-01

    The role of brain-derived neurotrophic factor (BDNF) in sensory hypersensitivity has been suggested; however the molecular mechanisms and signal transduction that regulate BDNF expression in primary afferent neurons during visceral inflammation are not clear. Here we used a rat model of cystitis and found that the mRNA and protein levels of BDNF were increased in the L6 dorsal root ganglia (DRG) in response to bladder inflammation. BDNF up-regulation in the L6 DRG was triggered by endogenous nerve growth factor (NGF) because neutralization of NGF with a specific NGF antibody reduced BDNF levels during cystitis. The neutralizing NGF antibody also subsequently reduced cystitis-induced up-regulation of the serine/threonine kinase Akt activity in L6 DRG. To examine whether the NGF-induced Akt activation led to BDNF up-regulation in DRG in cystitis, we found that in cystitis the phospho-Akt immunoreactivity was co-localized with BDNF in L6 DRG, and prevention of the endogenous Akt activity in the L6 DRG by inhibition of phosphoinositide 3-kinase (PI3K) with a potent inhibitor LY294002 reversed cystitis-induced BDNF up-regulation. Further study showed that application of NGF to the nerve terminals of the ganglion-nerve two-compartmented preparation enhanced BDNF expression in the DRG neuronal soma; which was reduced by pre-treatment of the ganglia with the PI3K inhibitor LY294002 and wortmannin. These in vivo and in vitro experiments indicated that NGF played an important role in the activation of Akt and subsequent up-regulation of BDNF in the sensory neurons in visceral inflammation such as cystitis. PMID:24303055

  4. Growth factor involvement in tension-induced skeletal muscle growth

    NASA Technical Reports Server (NTRS)

    Vandenburgh, H. H.

    1987-01-01

    Muscle tissue culture techniques were developed to grow skeletal myofibers which differentiate into more adult-like myofibers. Mechanical simulation studies of these muscle cells in a newly developed mechanical cell simulator can now be performed to study growth processes in skeletal muscle. Conditions in the mechanical cell simulator were defined where mechanical activity can either prevent muscle wasting or stimulate muscle growth. The role of endogenous and exogenous growth factors in tension-induced muscle growth is being investigated under the defined conditions of tissue culture.

  5. Feedlot performance, carcass characteristics, hormones, and metabolites in steers actively immunized against growth hormone-releasing factor.

    PubMed

    Harvey, R W; Armstrong, J D; Heimer, E P; Campbell, R M

    1993-11-01

    Large-framed Simmental and Charolais steers were actively immunized against growth hormone-releasing factor (GRF) to evaluate the effect on growth, carcass characteristics (especially intramuscular fat deposition), and concentrations of somatotropin (ST) and IGF-I. Primary immunizations of 1.5 mg of GRF-(1-29)-Gly-Gly-Cys-NH2 conjugated to 1.5 mg of human serum albumin (GRFi, n = 12) or 1.5 mg of human serum albumin (HSAi, n = 12) were given at approximately 10 mo of age. Booster immunizations of .5 mg of the appropriate antigen were given at d 49 and 125. Weights of steers administered GRFi were less (P < .05) than those given HSAi at 126 d (34.6 kg) or at 262 d (48.2 kg) after treatment. Carcass weights were 28.2 kg less (P < .01) for GRFi than for HSAi steers. Dry matter intake was not affected by immunization treatment, whereas feed efficiency was reduced in GRFi steers. Marbling scores were higher (P < .05) for HSAi than for GRFi steers but similar percentages (83.3) of both treatments graded Low Choice or higher. Rib sections of GRFi steers contained more fat (31.2 vs 25.0%) and less lean (63.3 vs 68.4%) than those of HSAi steers (P < .05). A breed x treatment interaction was observed for percentage of fat within the trimmed longissimus muscle (P < .05); percentage of fat was similar for Charolais and Simmental steers when immunized against HSAi but was higher for Simmental than for Charolais when immunized against GRFi.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Expression and characterization of biologically active human hepatocyte growth factor (HGF) by insect cells infected with HGF-recombinant baculovirus.

    PubMed

    Yee, C J; DeFrances, M C; Bell, A; Bowen, W; Petersen, B; Michalopoulos, G K; Zarnegar, R

    1993-08-10

    A cDNA containing the entire coding sequence of human hepatocyte growth factor (HGF) [also known as scatter factor (SF)] was inserted into the genome of Autographa california nuclear polyhedrosis virus (baculovirus) adjacent to the polyhedrin promoter by homologous recombination. Insect cells (Spodoptera frugiperda) infected with the recombinant virus secrete relatively high levels (3-8 mg/L) of biologically active HGF into the culture medium. The recombinant HGF induces pronounced morphological changes and scattering of primary cultures of rat, mouse, and human hepatocytes within 24 h after plating and stimulates DNA synthesis in these cells with the same magnitude as native HGF derived from human placenta or rabbit serum. The human recombinant HGF produced by the insect cells is N-glycosylated, binds to heparin like native HGF, and is recognized by polyclonal antiserums raised against human or rabbit HGF as assessed by immunoblot, ELISA, and immunoneutralization experiments. Metabolic radiolabeling with L-[35S]methionine (pulse-chase experiments) as well as Western blot analysis indicates that the recombinant HGF is synthesized and secreted by the infected insect cells as the unprocessed single-chain form (pro-HGF) when the cells are cultured in serum-free medium. However, when the infected insect cells are cultured in insect culture medium (Grace's medium) containing fetal bovine serum, the secreted HGF is present mainly in the mature heterodimeric form. Addition of serum to the baculovirus-expressed single-chain [125I]HGF in a cell-free system results in conversion to the heterodimeric two-chain form, and the activation is prevented by the serine protease inhibitor PMSF. Incubation of 125I-labeled pro-HGF with rat liver or spleen extracts resulted in conversion of pro-HGF to the heterodimeric two-chain form. A truncated form of HGF containing the N-terminal portion of HGF (kringles 1-3) was also produced in the same expression system. This deleted HGF, by

  7. Peroxisome proliferator-activated receptor γ agonist efatutazone impairs transforming growth factor β2-induced motility of epidermal growth factor receptor tyrosine kinase inhibitor-resistant lung cancer cells.

    PubMed

    Serizawa, Masakuni; Murakami, Haruyasu; Watanabe, Masaru; Takahashi, Toshiaki; Yamamoto, Nobuyuki; Koh, Yasuhiro

    2014-06-01

    Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) are effective for non-small cell lung cancers (NSCLC) with EGFR-activating mutations. However, most responders develop resistance. Efatutazone, a novel peroxisome proliferator-activated receptor gamma (PPARγ) agonist, is currently under clinical evaluation; it has antiproliferative effects and induces cellular morphological changes and differentiation. The present study investigated the effects of efatutazone in EGFR-TKI-resistant NSCLC cells, while focusing on cell motility. The PC-9-derived NSCLC cell lines PC-9ER and PC-9ZD, resistant to EGFR-TKI due to v-crk avian sarcoma virus CT10 oncogene homolog-like (CRKL) amplification-induced phosphatidylinositol 3-kinase (PI3K)/v-akt murine thymoma viral oncogene homolog (AKT) activation and an EGFR T790M mutation, respectively, were used. These cells exhibit enhanced cell motility due to transforming growth factor β (TGF-β)/Smad2 family member 2 (Smad2) pathway activation. Efatutazone had no growth-inhibitory effect on the tested cells but inhibited the motility of EGFR-TKI-resistant cells in wound closure and transwell assays. Efatutazone plus erlotinib treatment provided greater inhibition of PC-9ER cell migration than efatutazone or erlotinib alone. Efatutazone suppressed increased TGF-β2 secretion from both cell lines (shown by ELISA) and downregulation of TGF-β2 transcription (observed by quantitative RT-PCR). Immunoblot analysis and luciferase assays revealed that efatutazone suppressed Smad2 phosphorylation and its transcriptional activity. These results suggest that efatutazone inhibits cell motility by antagonizing the TGF-β/Smad2 pathway and effectively prevents metastasis in NSCLC patients with acquired resistance to EGFR-TKI regardless of the resistance mechanism.

  8. A Natural Hepatocyte Growth Factor/Scatter Factor Autocrine Loop in Myoblast Cells and the Effect of the Constitutive Met Kinase Activation on Myogenic Differentiation

    PubMed Central

    Anastasi, Sergio; Giordano, Silvia; Sthandier, Olga; Gambarotta, Giovanna; Maione, Rossella; Comoglio, Paolo; Amati, Paolo

    1997-01-01

    As a rule, hepatocyte growth factor/scatter factor (HGF/SF) is produced by mesenchymal cells, while its receptor, the tyrosine kinase encoded by the met proto-oncogene, is expressed by the neighboring epithelial cells in a canonical paracrine fashion. In the present work we show that both HGF/SF and met are coexpressed by undifferentiated C2 mouse myoblasts. In growing cells, the autocrine loop is active as the receptor exhibits a constitutive phosphorylation on tyrosine that can be abrogated by exogenously added anti-HGF/SF neutralizing antibodies. The transcription of HGF/SF and met genes is downregulated when myoblasts stop proliferating and differentiate. The coexpression of HGF/SF and met genes is not exclusive to C2 cells since it has been assessed also in other myogenic cell lines and in mouse primary satellite cells, suggesting that HGF/SF could play a role in muscle development through an autocrine way. To analyze the biological effects of HGF/SF receptor activation, we stably expressed the constitutively activated receptor catalytic domain (p65tpr-met) in C2 cells. This active kinase determined profound changes in cell shape and inhibited myogenesis at both morphological and biochemical levels. Notably, a complete absence of muscle regulatory markers such as MyoD and myogenin was observed in p65tpr-met highly expressing C2 clones. We also studied the effects of the ectopic expression of human isoforms of met receptor (h-met) and of HGF/SF (h-HGF/SF) in stable transfected C2 cells. Single constitutive expression of h-met or h-HGF/SF does not alter substantially the growth and differentiation properties of the myoblast cells, probably because of a species-specific ligand–receptor interaction. A C2 clone expressing simultaneously both h-met and h-HGF/SF is able to grow in soft agar and shows a decrease in myogenic potential comparable to that promoted by p65tpr-met kinase. These data indicate that a met kinase signal released from differentiation

  9. Interstitial fibrosis and growth factors.

    PubMed Central

    Lasky, J A; Brody, A R

    2000-01-01

    Interstitial pulmonary fibrosis (IPF) is scarring of the lung caused by a variety of inhaled agents including mineral particles, organic dusts, and oxidant gases. The disease afflicts millions of individuals worldwide, and there are no effective therapeutic approaches. A major reason for this lack of useful treatments is that few of the molecular mechanisms of disease have been defined sufficiently to design appropriate targets for therapy. Our laboratory has focused on the molecular mechanisms through which three selected peptide growth factors could play a role in the development of IPF. Hundreds of growth factors and cytokines could be involved in the complex disease process. We are studying platelet-derived growth factor because it is the most potent mesenchymal cell mitogen yet described, transforming growth factor beta because it is a powerful inducer of extracellular matrix (scar tissue) components by mesenchymal cells, and tumor necrosis factor alpha because it is a pleiotropic cytokine that we and others have shown is essential for the development of IPF in animal models. This review describes some of the evidence from studies in humans, in animal models, and in vitro, that supports the growth factor hypothesis. The use of modern molecular and transgenic technologies could elucidate those targets that will allow effective therapeutic approaches. Images Figure 1 Figure 2 PMID:10931794

  10. Evidence for nerve growth factor-potentiating activities of the nonpeptidic compound SR 57746A in PC12 cells.

    PubMed

    Pradines, A; Magazin, M; Schiltz, P; Le Fur, G; Caput, D; Ferrara, P

    1995-05-01

    SR 57746A (1-[2-(naphth-2-yl)ethyl]-4-(3-trifluoromethylphenyl)-1,2,5,6- tetrahydropyridine hydrochloride) exhibits neurotrophic activities in vivo and in vitro. We used the rat pheochromocytoma PC12 cell line to investigate in vitro cellular changes induced by SR 57746A. A significant increase in the percentage of cells bearing neurite-like processes was obtained in cells treated by SR 57746A and nerve growth factor (NGF) compared with NGF treatment alone. SR 57746A added alone, however, had no effect on morphogenesis or on survival of cells in serum-free medium. In contrast, SR 57746A induced a "priming" effect on PC12 cells for neurite outgrowth within 6 h of addition of the protein tyrosine kinase inhibitor genistein. An increase in alpha-actinin content resulted from treatment with SR 57746A. Expression of NGF-mediated acetylcholinesterase and choline acetyltransferase was enhanced within 5 days by SR 57746A. The molecule also induced rapid F-actin redistribution. Within 2 min of incubation, outgrowth of F-actin-containing filopodia was clearly visible at the cell periphery, as previously shown with NGF. It is interesting that this effect of SR 57746A could be mimicked by protein tyrosine kinase inhibitors and abolished by preincubation with sodium orthovanadate, a protein tyrosine phosphatase inhibitor. PMID:7722483

  11. Modulation of the binding of basic fibroblast growth factor and heparanase activity by purified λ-carrageenan oligosaccharides.

    PubMed

    Niu, Ting-Ting; Zhang, Dong-Sheng; Chen, Hai-Min; Yan, Xiao-Jun

    2015-07-10

    Inhibitors of angiogenesis and tumor metastasis are increasingly emerging as promising agents for cancer therapy. Here, we report λ-carrageenan oligosaccharides (λ-COs), highly-sulfated oligosaccharides acting as a basic fibroblast growth factor (bFGF) antagonist and heparanase inhibitor. λ-COs with degree of polymerization (DP) from 2 to 8 degraded by λ-carrageenase were separated and purified. The structures were identified by mass spectrometry. The activities of λ-COs are closely related with DP. λ-COs showed no cytotoxicity, but inactivated bFGF-induced cell proliferation; among them, λ-carraheptaose showed highest capability. Only λ-carraheptaose can effectively bind to bFGF. Binding kinetics showed that λ-carraheptaose and suramin had different binding modes, i.e., suramin displayed a fast association and fast dissociation, but λ-carraheptaose exhibited a slow association and slow dissociation. In addition, λ-COs showed the highest heparanase inhibitory ability and abolished the endothelial cell invasion. Thus, λ-COs may provide a tool to develop of new carbohydrate-based therapeutics against cancer and angiogenesis.

  12. Vascular endothelial growth factor-related protein: a ligand and specific activator of the tyrosine kinase receptor Flt4.

    PubMed Central

    Lee, J; Gray, A; Yuan, J; Luoh, S M; Avraham, H; Wood, W I

    1996-01-01

    The tyrosine kinases Flt4, Flt1, and Flk1 (or KDR) constitute a family of endothelial cell-specific receptors with seven immunoglobulin-like domains and a split kinase domain. Flt1 and Flk1 have been shown to play key roles in vascular development; these two receptors bind and are activated by vascular endothelial growth factor (VEGF). No ligand has been identified for Flt4, whose expression becomes restricted during development to the lymphatic endothelium. We have identified cDNA clones from a human glioma cell line that encode a secreted protein with 32% amino acid identity to VEGF. This protein, designated VEGF-related protein (VRP), specifically binds to the extracellular domain of Flt4, stimulates the tyrosine phosphorylation of Flt4 expressed in mammalian cells, and promotes the mitogenesis of human lung endothelial cells. VRP fails to bind appreciably to the extracellular domain of Flt1 or Flk1. The protein contains a C-terminal, cysteine-rich region of about 180 amino acids that is not found in VEGF. A 2.4-kb VRP mRNA is found in several human tissues including adult heart, placenta, ovary, and small intestine and in fetal lung and kidney. Images Fig. 1 Fig. 2 Fig. 3 Fig. 6 PMID:8700872

  13. A novel signaling pathway of tissue kallikrein in promoting keratinocyte migration: Activation of proteinase-activated receptor 1 and epidermal growth factor receptor

    SciTech Connect

    Gao, Lin; Chao, Lee; Chao, Julie

    2010-02-01

    Biological functions of tissue kallikrein (TK, KLK1) are mainly mediated by kinin generation and subsequent kinin B2 receptor activation. In this study, we investigated the potential role of TK and its signaling pathways in cultured human keratinocyte migration and in a rat skin wound healing model. Herein, we show that TK promoted cell migration and proliferation in a concentration- and time-dependent manner. Inactive TK or kinin had no significant effect on cell migration. Interestingly, cell migration induced by active TK was not blocked by icatibant or L-NAME, indicating an event independent of kinin B2 receptor and nitric oxide formation. TK's stimulatory effect on cell migration was inhibited by small interfering RNA for proteinase-activated receptor 1 (PAR{sub 1}), and by PAR{sub 1} inhibitor. TK-induced migration was associated with increased phosphorylation of epidermal growth factor receptor (EGFR) and extracellular signal-regulated kinase (ERK), which was blocked by inhibition of protein kinase C (PKC), Src, EGFR and ERK. TK-induced cell migration and EGFR phosphorylation were blocked by metalloproteinase (MMP) inhibitor, heparin, and antibodies against EGFR external domain, heparin-binding EGF-like growth factor (HB-EGF) and amphiregulin (AR). Local application of TK promoted skin wound healing in rats, whereas icatibant and EGFR inhibitor blocked TK's effect. Skin wound healing was further delayed by aprotinin and neutralizing TK antibody. This study demonstrates a novel role of TK in skin wound healing and uncovers new signaling pathways mediated by TK in promoting keratinocyte migration through activation of the PAR{sub 1}-PKC-Src-MMP pathway and HB-EGF/AR shedding-dependent EGFR transactivation.

  14. Kaiso depletion attenuates transforming growth factor-β signaling and metastatic activity of triple-negative breast cancer cells

    PubMed Central

    Bassey-Archibong, B I; Kwiecien, J M; Milosavljevic, S B; Hallett, R M; Rayner, L G A; Erb, M J; Crawford-Brown, C J; Stephenson, K B; Bédard, P-A; Hassell, J A; Daniel, J M

    2016-01-01

    Triple-negative breast cancers (TNBCs) represent a subset of breast tumors that are highly aggressive and metastatic, and are responsible for a disproportionate number of breast cancer-related deaths. Several studies have postulated a role for the epithelial-to-mesenchymal transition (EMT) program in the increased aggressiveness and metastatic propensity of TNBCs. Although EMT is essential for early vertebrate development and wound healing, it is frequently co-opted by cancer cells during tumorigenesis. One prominent signaling pathway involved in EMT is the transforming growth factor-β (TGFβ) pathway. In this study, we report that the novel POZ-ZF transcription factor Kaiso is highly expressed in TNBCs and correlates with a shorter metastasis-free survival. Notably, Kaiso expression is induced by the TGFβ pathway and silencing Kaiso expression in the highly invasive breast cancer cell lines, MDA-MB-231 (hereafter MDA-231) and Hs578T, attenuated the expression of several EMT-associated proteins (Vimentin, Slug and ZEB1), abrogated TGFβ signaling and TGFβ-dependent EMT. Moreover, Kaiso depletion attenuated the metastasis of TNBC cells (MDA-231 and Hs578T) in a mouse model. Although high Kaiso and high TGFβR1 expression is associated with poor overall survival in breast cancer patients, overexpression of a kinase-active TGFβR1 in the Kaiso-depleted cells was insufficient to restore the metastatic potential of these cells, suggesting that Kaiso is a key downstream component of TGFβ-mediated pro-metastatic responses. Collectively, these findings suggest a critical role for Kaiso in TGFβ signaling and the metastasis of TNBCs. PMID:26999717

  15. Kaiso depletion attenuates transforming growth factor-β signaling and metastatic activity of triple-negative breast cancer cells.

    PubMed

    Bassey-Archibong, B I; Kwiecien, J M; Milosavljevic, S B; Hallett, R M; Rayner, L G A; Erb, M J; Crawford-Brown, C J; Stephenson, K B; Bédard, P-A; Hassell, J A; Daniel, J M

    2016-01-01

    Triple-negative breast cancers (TNBCs) represent a subset of breast tumors that are highly aggressive and metastatic, and are responsible for a disproportionate number of breast cancer-related deaths. Several studies have postulated a role for the epithelial-to-mesenchymal transition (EMT) program in the increased aggressiveness and metastatic propensity of TNBCs. Although EMT is essential for early vertebrate development and wound healing, it is frequently co-opted by cancer cells during tumorigenesis. One prominent signaling pathway involved in EMT is the transforming growth factor-β (TGFβ) pathway. In this study, we report that the novel POZ-ZF transcription factor Kaiso is highly expressed in TNBCs and correlates with a shorter metastasis-free survival. Notably, Kaiso expression is induced by the TGFβ pathway and silencing Kaiso expression in the highly invasive breast cancer cell lines, MDA-MB-231 (hereafter MDA-231) and Hs578T, attenuated the expression of several EMT-associated proteins (Vimentin, Slug and ZEB1), abrogated TGFβ signaling and TGFβ-dependent EMT. Moreover, Kaiso depletion attenuated the metastasis of TNBC cells (MDA-231 and Hs578T) in a mouse model. Although high Kaiso and high TGFβR1 expression is associated with poor overall survival in breast cancer patients, overexpression of a kinase-active TGFβR1 in the Kaiso-depleted cells was insufficient to restore the metastatic potential of these cells, suggesting that Kaiso is a key downstream component of TGFβ-mediated pro-metastatic responses. Collectively, these findings suggest a critical role for Kaiso in TGFβ signaling and the metastasis of TNBCs.

  16. Importance of osteoprotegrin and receptor activator of nuclear factor κB in breast cancer response to hepatocyte growth factor and the bone microenvironment in vitro.

    PubMed

    Owen, Sioned; Sanders, Andrew J; Mason, Malcolm D; Jiang, Wen G

    2016-03-01

    Osteoprotegrin (OPG), receptor activator of nuclear factor κB (RANK) and RANK ligand (RANKL) are signal transducers which have pleiotropic actions. Each tumour necrosis factor receptor superfamily member has unique structural attributes which directly couples them to signalling pathways involved in cell proliferation, differentiation and survival. Previous studies have clinically linked OPG, RANK and RANKL to increasing tumour burden, metastatic bone involvement and estrogen status. This study aimed to establish the potential implications of targeting endogenously produced OPG and RANK in the osteotropic breast cancer cell line MDA-MB‑231 in vitro. Subsequently this study also aimed to explore the potential links between these molecules with regards to hepatocyte growth factor (HGF) signalling and extracted bone proteins (BME). OPG and RANK expression was successfully suppressed using hammerhead ribozyme technology. Subsequently effects were explored in MDA-MB‑231 cell proliferation, matrix adhesion, migration and invasion in vitro function assays. Reduced OPG expression resulted in increased breast cancer cell migration and invasion. These increases, particularly invasion, appeared to however be reduced under the influence of the exogenous stimuli (HGF and BME). In contrast, suppression of RANK in MDA-MB‑231 breast cancer cells resulted in decreased cancer cell proliferation, matrix-adhesion, motility and invasion with little cumulative effect being noted after the addition of exogenous stimuli. The complexity of the bone environment underpins the vast number of soluble factors and signalling pathways which can influence osteotropic cancer behaviour and progression. Further work into elucidating all the pathways affected could potentially lead to better identification of those patients most at risk. PMID:26781475

  17. Epidermal Growth Factor Receptor Transactivation Is Required for Mitogen-Activated Protein Kinase Activation by Muscarinic Acetylcholine Receptors in HaCaT Keratinocytes

    PubMed Central

    Ockenga, Wymke; Kühne, Sina; Bocksberger, Simone; Banning, Antje; Tikkanen, Ritva

    2014-01-01

    Non-neuronal acetylcholine plays a substantial role in the human skin by influencing adhesion, migration, proliferation and differentiation of keratinocytes. These processes are regulated by the Mitogen-Activated Protein (MAP) kinase cascade. Here we show that in HaCaT keratinocytes all five muscarinic receptor subtypes are expressed, but M1 and M3 are the subtypes involved in mitogenic signaling. Stimulation with the cholinergic agonist carbachol leads to activation of the MAP kinase extracellular signal regulated kinase, together with the protein kinase Akt. The activation is fully dependent on the transactivation of the epidermal growth factor receptor (EGFR), which even appears to be the sole pathway for the muscarinic receptors to facilitate MAP kinase activation in HaCaT cells. The transactivation pathway involves a triple-membrane-passing process, based on activation of matrix metalloproteases, and extracellular ligand release; whereas phosphatidylinositol 3-kinase, Src family kinases or protein kinase C do not appear to be involved in MAP kinase activation. Furthermore, phosphorylation, ubiquitination and endocytosis of the EGF receptor after cholinergic transactivation are different from that induced by a direct stimulation with EGF, suggesting that ligands other than EGF itself mediate the cholinergic transactivation. PMID:25421240

  18. Blockade of Ca2+-activated K+ channels inhibits proliferation of human endothelial cells induced by basic fibroblast growth factor.

    PubMed

    Wiecha, J; Münz, B; Wu, Y; Noll, T; Tillmanns, H; Waldecker, B

    1998-01-01

    Basic fibroblast growth factor (bFGF) exerts angiogenic and mitogenic properties in human tissue. Since changes in ion currents modulate essential Ca2+-dependent intracellular pathways in endothelial cells, we have investigated a possible contribution of Ca2+-activated K+ channels (BKCa) on bFGF-induced endothelial cell proliferation. The patch-clamp technique was used to identify BKCa and to study their modulation by bFGF in cultured endothelial cells of human umbilical cord veins (HUVEC). Cell counts of HUVEC were carried out on different days to analyze bFGF-induced cell proliferation and its influence by the specific BKCa blocker iberiotoxin (IBX). Using single-channel recordings, we found characteristic BKCa with a single-channel slope conductance of 170.3 +/- 2.1 pS (n = 7), half-maximal activation at internal pCa = 5.7 (n = 5; test potential: 80 mV), and dose-dependent block by IBX (25-100 nmol/l). In cell-attached patches bFGF (50 ng/ml) caused a significant increase in the open-state probability (NPo) after 6 min at test potentials of 80 and 100 mV (n = 28; p < 0.001), respectively, which lasted up to 30 min. After preincubation with pertussis toxin (100 ng/ml; 4 h) bFGF superfusion did not cause a significant increase in BKCa activity until 25 min had passed (n = 20; p < 0.01). Addition of 100 nmol/l IBX to the pipette solution caused a total block of BKCa within 2 min in cell-attached patches, whereas bFGF (50 ng/ml) was not able to activate BKCa. When incubated with IBX (25-100 nmol/l) every 2 days, bFGF-induced proliferation of HUVEC was significantly decreased by 50 (-41%) and 100 nmol/l (-50%) IBX (n = 5; p < 0.001) after 7 days. We conclude that activation of BKCa by bFGF may play an important role in bFGF-induced proliferation of human endothelial cells and thus might be important in the process of angiogenesis and vascular remodelling.

  19. Expression of platelet-derived growth factor and its receptors in normal human liver and during active hepatic fibrogenesis.

    PubMed Central

    Pinzani, M.; Milani, S.; Herbst, H.; DeFranco, R.; Grappone, C.; Gentilini, A.; Caligiuri, A.; Pellegrini, G.; Ngo, D. V.; Romanelli, R. G.; Gentilini, P.

    1996-01-01

    Expression of platelet-derived growth factor (PDGF) and its receptor (R) subunits was evaluated in normal human liver and in cirrhotic liver tissue by in situ hybridization and immunohistochemistry. In normal liver, PDGF and PDGF-R subunit expression was limited to a few mesenchymal cells of the portal tract stroma and vessels. In cirrhotic liver, PDGF-A and -B chain mRNA expression was markedly increased and was co-distributed with immunoreactivity for PDGF-AA and -BB in infiltrating inflammatory cells and along vascular structures within fibrous septa. These aspects were paralleled by a marked overexpression of PDGF-R alpha- and beta-subunit mRNAs and of the relative immunoreactivities in a wide range of mesenchymal cells in fibrous septa and in perisinusoidal alpha-smooth-muscle-actin-positive cells. In general expression and distribution of PDGF-R subunits appeared to be related to the activation of different mesenchymal cell types involved in the fibroproliferative process. Therefore, we evaluated the expression of PDGF-R subunits in liver tissue specimens with increasing degrees of necroinflammatory activity. The results of this additional study confirmed that expression of PDGF-R subunits is highly correlated with the severity of histological lesions and collagen deposition. Our results, providing evidence for a functional involvement of PDGF/PDGF-R in liver fibrogenesis, greatly support the results of previous in vitro studies and direct attention toward pharmacological strategies able to affect the series of signaling events arising from the autophosphorylation of PDGF-R subunits. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 PMID:8774134

  20. Intercalated chemotherapy and erlotinib for non-small cell lung cancer (NSCLC) with activating epidermal growth factor receptor (EGFR) mutations

    PubMed Central

    Zwitter, Matjaz; Rajer, Mirjana; Stanic, Karmen; Vrankar, Martina; Doma, Andrej; Cuderman, Anka; Grmek, Marko; Kern, Izidor; Kovac, Viljem

    2016-01-01

    ABSTRACT Among attempts to delay development of resistance to tyrosine kinase inhibitors (TKIs) in patients with advanced non-small cell lung cancer (NSCLC) with activating mutations of epidermal growth factor receptor (EGFR), intercalated therapy has not been properly evaluated. In a phase II trial, 38 patients with EGFR mutated NSCLC in advanced stage were treated with 4 to 6 3-weekly cycles of intercalated schedule with gemcitabine (1250 mg/m2, days 1 and 4), cisplatin (75 mg/m2, day 2) and erlotinib (150 mg, days 5 – 15), followed by continuous erlotinib as maintenance. In addition to standard radiologic evaluation according to RECIST, PET/CT was done prior to treatment and at 6 months, using PERCIST as a method for assessment of response. The primary endpoint was progression-free survival (PFS). In general, tolerance to treatment was good, even among 8 patients with performance status 2–3 and 13 patients with brain metastases; grade 4 toxicity included 2 cases of neutropenia and 4 thrombo-embolic events. Complete response (CR) or partial response (PR) were seen in 15 (39.5%) and 17 (44.7%) cases, respectively. All cases of CR were confirmed also by PET/CT. Median PFS was 23.4 months and median overall survival (OS) was 38.3  months. After a median follow-up of 35 months, 8 patients are still in CR and on maintenance erlotinib. In conclusion, intercalated treatment for treatment-naive patients with EGFR activating mutations leads to excellent response rate and prolonged PFS and survival. Comparison of the intercalated schedule to monotherapy with TKIs in a randomized trial is warranted. PMID:27261103

  1. Mechano-growth factor induces migration of rat mesenchymal stem cells by altering its mechanical properties and activating ERK pathway

    SciTech Connect

    Wu, Jiamin; Wu, Kewen; Lin, Feng; Luo, Qing; Yang, Li; Shi, Yisong; Song, Guanbin; Sung, Kuo-Li Paul

    2013-11-08

    Highlights: •MGF induced the migration of rat MSC in a concentration-dependent manner. •MGF enhanced the mechanical properties of rMSC in inducing its migration. •MGF activated the ERK 1/2 signaling pathway of rMSC in inducing its migration. •rMSC mechanics may synergy with ERK 1/2 pathway in MGF-induced rMSC migration. -- Abstract: Mechano-growth factor (MGF) generated by cells in response to mechanical stimulation has been identified as a mechano effector molecule, playing a key role in regulating mesenchymal stem cell (MSC) function, including proliferation and migration. However, the mechanism(s) underlying how MGF-induced MSC migration occurs is still unclear. In the present study, MGF motivated migration of rat MSCs (rMSCs) in a concentration-dependent manner and optimal concentration of MGF at 50 ng/mL (defined as MGF treatment in this paper) was demonstrated. Notably, enhancement of mechanical properties that is pertinent to cell migration, such as cell traction force and cell stiffness were found to respond to MGF treatment. Furthermore, MGF increased phosphorylation of extracellular signal-regulated kinase (ERK), ERK inhibitor (i.e., PD98059) suppressed ERK phosphorylation, and abolished MGF-induced rMSC migration were found, demonstrating that ERK is involved molecule for MGF-induced rMSC migration. These in vitro evidences of MGF-induced rMSC migration and its direct link to altering rMSC mechanics and activating the ERK pathway, uncover the underlying biomechanical and biological mechanisms of MGF-induced rMSC migration, which may help find MGF-based application of MSC in clinical therapeutics.

  2. A Heparin-Mimicking Block Copolymer Both Stabilizes and Increases the Activity of Fibroblast Growth Factor 2 (FGF2)

    PubMed Central

    2016-01-01

    Fibroblast growth factor 2 (FGF2) is a protein involved in cellular functions in applications such as wound healing and tissue regeneration. Stabilization of this protein is important for its use as a therapeutic since the native protein is unstable during storage and delivery. Additionally, the ability to increase the activity of FGF2 is important for its application, particularly in chronic wound healing and the treatment of various ischemic conditions. Here we report a heparin mimicking block copolymer, poly(styrenesulfonate-co-poly(ethylene glycol) methyl ether methacrylate)-b-vinyl sulfonate) (p(SS-co-PEGMA)-b-VS, that contains a segment that enhances the stability of FGF2 and one that binds to the FGF2 receptor. The FGF2 conjugate retained activity after exposure to refrigeration (4 °C) and room temperature (23 °C) for 7 days, while unmodified FGF2 was inactive after these standard storage conditions. A cell study performed with a cell line lacking native heparan sulfate proteoglycans indicated that the conjugated block copolymer facilitated binding of FGF2 to its receptor similar to the addition of heparin to FGF2. A receptor-based enzyme-linked immunosorbant assay (ELISA) confirmed the results. The conjugate also increased the migration of endothelial cells by 80% compared to FGF2 alone. Additionally, the FGF2-p(SS-co-PEGMA)-b-VS stimulated endothelial cell sprouting 250% better than FGF2 at low concentration. These data verify that this rationally designed protein-block copolymer conjugate enhances receptor binding, cellular processes such as migration and tube-like formation, and stability, and suggest that it may be useful for applications in biomaterials, tissue regeneration, and wound healing. PMID:27580376

  3. Preparation and antitumor effect of a toxin-linked conjugate targeting vascular endothelial growth factor receptor and urokinase plasminogen activator

    PubMed Central

    Xiang, Ying; Li, Qiying; Huang, Dehong; Tang, Xianjun; Wang, Li; Shi, Yang; Zhang, Wenjun; Yang, Tao; Xiao, Chunyan

    2015-01-01

    The aberrant signaling activation of vascular endothelial growth factor receptor (VEGFR) and urokinase plasminogen activator (uPA) is a common characteristic of many tumors, including lung cancer. Accordingly, VEGFR and uPA have emerged as attractive targets for tumor. KDR (Flk-1/VEGFR-2), a member of the VEGFR family, has been recognized as an important target for antiangiogenesis in tumor. In this study, a recombinant immunotoxin was produced to specifically target KDR-expressing tumor vascular endothelial cells and uPA-expressing tumor cells and mediate antitumor angiogenesis and antitumor effect. Based on its potent inhibitory effect on protein synthesis, Luffin-beta (Lβ) ribosome-inactivating protein was selected as part of a recombinant fusion protein, a single-chain variable fragment against KDR (KDRscFv)-uPA cleavage site (uPAcs)-Lβ-KDEL (named as KPLK). The KDRscFv-uPAcs-Lβ-KDEL (KPLK) contained a single-chain variable fragment (scFv) against KDR, uPAcs, Lβ, and the retention signal for endoplasmic reticulum proteins KDEL (Lys-Asp-Glu-Leu). The KPLK-expressing vector was expressed in Escherichia coli, and the KPLK protein was isolated with nickel affinity chromatography and gel filtration chromatography. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis test demonstrated KPLK was effectively expressed. Result of in vitro cell viability assay on non-small cell lung cancer (NSCLC) H460 cell line (uPA-positive cell) revealed that KPLK significantly inhibited cell proliferation, induced apoptosis, and accumulated cells in S and G2/M phases, but the normal cell line (human submandibular gland cell) was unaffected. These effects were enhanced when uPA was added to digest KPLK to release Lβ. For in vivo assay of KPLK, subcutaneous xenograft tumor model of nude mice were established with H460 cells. Growth of solid tumors was significantly inhibited in animals treated with KPLK up to 21 days, tumor weights were decreased, and the expression of

  4. Tricyclic antidepressant amitriptyline activates fibroblast growth factor receptor signaling in glial cells: involvement in glial cell line-derived neurotrophic factor production.

    PubMed

    Hisaoka, Kazue; Tsuchioka, Mami; Yano, Ryoya; Maeda, Natsuko; Kajitani, Naoto; Morioka, Norimitsu; Nakata, Yoshihiro; Takebayashi, Minoru

    2011-06-17

    Recently, both clinical and animal studies demonstrated neuronal and glial plasticity to be important for the therapeutic action of antidepressants. Antidepressants increase glial cell line-derived neurotrophic factor (GDNF) production through monoamine-independent protein-tyrosine kinase, extracellular signal-regulated kinase (ERK), and cAMP responsive element-binding protein (CREB) activation in glial cells (Hisaoka, K., Takebayashi, M., Tsuchioka, M., Maeda, N., Nakata, Y., and Yamawaki, S. (2007) J. Pharmacol. Exp. Ther. 321, 148-157; Hisaoka, K., Maeda, N., Tsuchioka, M., and Takebayashi, M. (2008) Brain Res. 1196, 53-58). This study clarifies the type of tyrosine kinase and mechanism of antidepressant-induced GDNF production in C6 glioma cells and normal human astrocytes. The amitriptyline (a tricyclic antidepressant)-induced ERK activation was specifically and completely inhibited by fibroblast growth factor receptor (FGFR) tyrosine kinase inhibitors and siRNA for FGFR1 and -2. Treatment with amitriptyline or several different classes of antidepressants, but not non-antidepressants, acutely increased the phosphorylation of FGFRs and FGFR substrate 2α (FRS2α). Amitriptyline-induced CREB phosphorylation and GDNF production were blocked by FGFR-tyrosine kinase inhibitors. Therefore, antidepressants activate the FGFR/FRS2α/ERK/CREB signaling cascade, thus resulting in GDNF production. Furthermore, we attempted to elucidate how antidepressants activate FGFR signaling. The effect of amitriptyline was inhibited by heparin, non-permeant FGF-2 neutralizing antibodies, and matrix metalloproteinase (MMP) inhibitors. Serotonin (5-HT) also increased GDNF production through FGFR2 (Tsuchioka, M., Takebayashi, M., Hisaoka, K., Maeda, N., and Nakata, Y. (2008) J. Neurochem. 106, 244-257); however, the effect of 5-HT was not inhibited by heparin and MMP inhibitors. These results suggest that amitriptyline-induced FGFR activation might occur through an extracellular pathway

  5. Resveratrol-induced Apoptosis is mediated by Early Growth Response-1, Krüppel-like Factor 4, and Activating Transcription Factor 3

    PubMed Central

    Whitlock, Nichelle C.; Bahn, Jae Hoon; Lee, Seong-Ho; Eling, Thomas E.; Baek, Seung Joon

    2010-01-01

    Resveratrol, a dietary phytoalexin readily available in the diet, is reported to possess anti-tumorigenic properties in several cancers, including colorectal. However, the underlying mechanism(s) involved is not completely understood. In the present study, we investigated the effect of resveratrol treatment on gene modulation in human colorectal cancer cells and identified activating transcription factor 3 (ATF3) as the most highly induced gene after treatment. We confirmed that resveratrol up-regulates ATF3 expression, both at the mRNA and protein level, and showed resveratrol involvement in ATF3 transcriptional regulation. Analysis of the ATF3 promoter revealed the importance of early growth response-1 (Egr-1; located at −245 to −236) and Krüppel-like factor 4 (KLF4; located at −178 to −174) putative binding sites in resveratrol-mediated ATF3 transactivation. Specificity of these sites to the Egr-1 and KLF4 protein was confirmed by electrophoretic mobility shift and chromatin immunoprecipitation assays. Resveratrol increased Egr-1 and KLF4 expression, which preceded ATF3 expression, and further suggests Egr-1 and KLF4 involvement in resveratrol-mediated activity. We provide evidence for Egr-1 and KLF4 interaction in the presence of resveratrol, which may facilitate ATF3 transcriptional regulation by this compound. Furthermore, we demonstrate induction of apoptosis by resveratrol is mediated, in part, by increased ATF3 expression. Taken together, these results provide a novel mechanism by which resveratrol induces ATF3 expression and represent an additional explanation of how resveratrol exerts its anti-tumorigenic effects in human colorectal cancer cells. PMID:21205742

  6. Integrin α5/β1 Mediates Fibronectin-dependent Epithelial Cell Proliferation through Epidermal Growth Factor Receptor Activation

    PubMed Central

    Kuwada, Scott K.; Li, Xiufen

    2000-01-01

    Human integrin α5 was transfected into the integrin α5/β1–negative intestinal epithelial cell line Caco-2 to study EGF receptor (EGFR) and integrin α5/β1 signaling interactions involved in epithelial cell proliferation. On uncoated or fibronectin-coated plastic, the integrin α5 and control (vector only) transfectants grew at similar rates. In the presence of the EGFR antagonistic mAb 225, the integrin α5 transfectants and controls were significantly growth inhibited on plastic. However, when cultured on fibronectin, the integrin α5 transfectants were not growth inhibited by mAb 225. The reversal of mAb 225–mediated growth inhibition on fibronectin for the integrin α5 transfectants correlated with activation of the EGFR, activation of MAPK, and expression of proliferating cell nuclear antigen. EGFR kinase activity was necessary for both MAPK activation and integrin α5/β1–mediated cell proliferation. Although EGFR activation occurred when either the integrin α5–transfected or control cells were cultured on fibronectin, coprecipitation of the EGFR with SHC could be demonstrated only in the integrin α5–transfected cells. These results suggest that integrin α5/β1 mediates fibronectin-induced epithelial cell proliferation through activation of the EGFR. PMID:10888683

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

    EPA Science Inventory

    Src-dependent Phosphorylation of the Epidermal Growth Factor Receptor on Tyrosine 845 Is Required for Zinc-induced Ras Activation
    Weidong Wu 1 , Lee M. Graves 2 , Gordon N. Gill 3 , Sarah J. Parsons 4 , and James M. Samet 5
    1 Center for Environmental Medicine and Lung Biolo...

  8. Matriptase is required for the active form of hepatocyte growth factor induced Met, focal adhesion kinase and protein kinase B activation on neural stem/progenitor cell motility.

    PubMed

    Fang, Jung-Da; Lee, Sheau-Ling

    2014-07-01

    Hepatocyte growth factor (HGF) is a chemoattractant and inducer for neural stem/progenitor (NS/P) cell migration. Although the type II transmembrane serine protease, matriptase (MTP) is an activator of the latent HGF, MTP is indispensable on NS/P cell motility induced by the active form of HGF. This suggests that MTP's action on NS/P cell motility involves mechanisms other than proteolytic activation of HGF. In the present study, we investigate the role of MTP in HGF-stimulated signaling events. Using specific inhibitors of phosphatidylinositol-3-kinase (PI3K), protein kinase B (Akt) or focal adhesion kinase (FAK), we demonstrated that in NS/P cells HGF-activated c-Met induces PI3k-Akt signaling which then leads to FAK activation. This signaling pathway ultimately induces MMP2 expression and NS/P cell motility. Knocking down of MTP in NS/P cells with specific siRNA impaired HGF-stimulation of c-Met, Akt and FAK activation, blocked HGF-induced production of MMP2 and inhibited HGF-stimulated NS/P cell motility. MTP-knockdown NS/P cells cultured in the presence of recombinant protein of MTP protease domain or transfected with the full-length wild-type but not the protease-defected MTP restored HGF-responsive events in NS/P cells. In addition to functioning as HGF activator, our data revealed novel function of MTP on HGF-stimulated c-Met signaling activation.

  9. Active post-marketing surveillance of the intralesional administration of human recombinant epidermal growth factor in diabetic foot ulcers

    PubMed Central

    2013-01-01

    Background After several exploratory and confirmatory clinical trials, the intralesional administration of human recombinant epidermal growth factor (hrEGF) has been approved for the treatment of advanced diabetic foot ulcers (DFU). The aim of this work was to evaluate the effectiveness and safety of this procedure in medical practice. Methods A prospective, post-marketing active pharmacosurveillance was conducted in 41 hospitals and 19 primary care polyclinics. Patients with DFU received hrEGF, 25 or 75 μg, intralesionally 3 times per week until complete granulation of the ulcer or 8 weeks maximum, adjuvant to standard wound care. Outcomes measured were complete granulation, amputations, and adverse events (AE) during treatment; complete lesion re-epithelization and relapses in follow-up (median: 1.2; maximum 4.2 years). Results The study included 1788 patients with 1835 DFU (81% Wagner’s grades 3 or 4; 43% ischemic) treated from May 2007 to April 2010. Complete granulation was observed in 76% of the ulcers in 5 weeks (median). Ulcer non-ischemic etiology (OR: 3.6; 95% CI: 2.8-4.7) and age (1.02; 1.01-1.03, for each younger year) were the main variables with influence on this outcome. During treatment, 220 (12%) amputations (171 major) were required in 214 patients, mostly in ischemic or Wagner’s grade 3 to 5 ulcers. Re-epithelization was documented in 61% of the 1659 followed-up cases; 5% relapsed per year. AE (4171) were reported in 47% of the subjects. Mild or moderate local pain and burning sensation, shivering and chills, were 87% of the events. Serious events, not related to treatment, occurred in 1.7% of the patients. Conclusions The favorable benefit/risk balance, confirms the beneficial clinical profile of intralesional hrEGF in the treatment of DFUs. PMID:24004460

  10. Dissecting the role of transforming growth factor-β1 in topmouth culter immunobiological activity: a fundamental functional analysis

    PubMed Central

    Qi, Pengzhi; Xie, Congxin; Guo, Baoying; Wu, Changwen

    2016-01-01

    Transforming growth factor-β1 (TGF-β1) has been proven to function primarily in mammalian immunobiological activity, but information regarding the immune role of TGF-β1 in teleosts is limited. In the present study, we describe the cDNA cloning and characterization of the TGF-β1 molecule in the topmouth culter. TGF-β1 is highly expressed in immune-related tissues of the culter, including the thymus, head kidney, and spleen. The recombinant culter TGF-β1 (cTGF-β1) was successfully expressed and purified in vitro, and the effects of cTGF-β1 on the mRNA expression of pro-inflammatory cytokines, such as TNF-α and IL-1β, in the absence or presence of LPS was determined in culter peripheral blood leukocytes. cTGF-β1 was found to have bipolar properties in inflammatory reactions. Additionally, to assess the immune role of teleost TGF-β1 in vivo, the expression of TGF-β1 in the culter thymus and spleen tissues induced by poly I:C were also examined. The expression of TGF-β1 was obviously up-regulated, as shown in the cell lines. However, the peak time of cTGF-β1 expression in the cell lines occurred significantly earlier than in the organic tissues under the same inducer, suggesting that the response of the teleost TGF-β1 molecule to exogenous infection depends on a more complicated signalling pathway in vivo than in vitro. PMID:27251472

  11. Insulin-like growth factor-1 potentiates platelet activation via the IRS/PI3Kalpha pathway.

    PubMed

    Hers, Ingeborg

    2007-12-15

    As insulin-like growth factor-1 (IGF-1) is present in the alpha granules of platelets and its receptor is expressed on the platelet surface, it may contribute to the amplification of platelet responses and pathogenesis of cardiovascular disease. The functional and signaling pathways that are involved in IGF-1 modulation of platelet function, however, are presently unknown. Here, I report that IGF-1 stimulation of platelets results in dose-dependent phosphorylation of the IGF receptor in the range of 1 to 100 nM. Phosphorylation of the IGF receptor is rapid and sustained, with maximal phosphorylation reached within 1 minute. Furthermore, IGF-1 stimulates tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) and IRS-2 and their association with the p85 subunit of phosphoinositide-3 kinase (PI3K). IGF-1-stimulated tyrosine phosphorylation of IRS-1 and IRS-2 and subsequent p85 binding is transient and precedes phosphorylation of protein kinase B (PKB) on Ser473. PAR-1-mediated platelet aggregation is potentiated by IGF-1 and this potentiation, together with PKB phosphorylation, is abolished by the PI3Kalpha inhibitors PI-103 and PIK-75. Importantly, the IGF receptor inhibitor NVP-AEW541 and the neutralization antibody alphaIR3 inhibit SFLLRN-stimulated aggregation, implicating IGF-1 in autocrine regulation of platelet function. These results demonstrate that IGF-1 activates the IGF receptor/IRS/PI3K/PKB pathway, and that PI3Kalpha is essential for the potentiatory effect of IGF-1 on platelet responses. PMID:17827393

  12. Dissecting the role of transforming growth factor-β1 in topmouth culter immunobiological activity: a fundamental functional analysis.

    PubMed

    Qi, Pengzhi; Xie, Congxin; Guo, Baoying; Wu, Changwen

    2016-06-02

    Transforming growth factor-β1 (TGF-β1) has been proven to function primarily in mammalian immunobiological activity, but information regarding the immune role of TGF-β1 in teleosts is limited. In the present study, we describe the cDNA cloning and characterization of the TGF-β1 molecule in the topmouth culter. TGF-β1 is highly expressed in immune-related tissues of the culter, including the thymus, head kidney, and spleen. The recombinant culter TGF-β1 (cTGF-β1) was successfully expressed and purified in vitro, and the effects of cTGF-β1 on the mRNA expression of pro-inflammatory cytokines, such as TNF-α and IL-1β, in the absence or presence of LPS was determined in culter peripheral blood leukocytes. cTGF-β1 was found to have bipolar properties in inflammatory reactions. Additionally, to assess the immune role of teleost TGF-β1 in vivo, the expression of TGF-β1 in the culter thymus and spleen tissues induced by poly I:C were also examined. The expression of TGF-β1 was obviously up-regulated, as shown in the cell lines. However, the peak time of cTGF-β1 expression in the cell lines occurred significantly earlier than in the organic tissues under the same inducer, suggesting that the response of the teleost TGF-β1 molecule to exogenous infection depends on a more complicated signalling pathway in vivo than in vitro.

  13. Glutathione levels discriminate between oxidative stress and transforming growth factor-beta signaling in activated rat hepatic stellate cells.

    PubMed

    De Bleser, P J; Xu, G; Rombouts, K; Rogiers, V; Geerts, A

    1999-11-26

    Reactive oxygen species are implicated in the pathogenesis of several diseases, including Alzheimer's disease, multiple sclerosis, human immunodeficiency virus, and liver fibrosis. With respect to liver fibrosis, we have investigated differences in antioxidant enzymes expression in stellate cells (SCs) and parenchymal cells from normal and CCl(4)-treated rat livers. We observed an increase in the expression of catalase in activated SCs. Treatment with transforming growth factor-beta (TGF-beta) increased the production of H(2)O(2). Treatment with catalase decreased TGF-beta expression. Addition of H(2)O(2) resulted in increased TGF-beta production. 3-Amino-1,2,4-triazole abolished the capacity of SCs to remove H(2)O(2). A paradoxical increase in capacity was observed when the cells were pretreated with diethyl maleate. Treatment with 3-amino-1, 2,4-triazole increased TGF-beta production. A paradoxical decrease of TGF-beta production was observed with diethyl maleate. Treatment of the cells with N-acetylcysteine resulted in increased TGF-beta production. TGF-beta decreased the capacity of the SCs to remove H(2)O(2.) An increase in the capacity to remove H(2)O(2) was observed when TGF-beta was removed by neutralizing antibodies. In conclusion, our results suggest: 1) a link between cellular GSH levels and TGF-beta production and 2) that cellular GSH levels discriminate whether H(2)O(2) is the result of oxidative stress or acts as second messenger in the TGF-beta signal transduction pathway.

  14. Insulin-like growth factor-1 potentiates platelet activation via the IRS/PI3Kalpha pathway.

    PubMed

    Hers, Ingeborg

    2007-12-15

    As insulin-like growth factor-1 (IGF-1) is present in the alpha granules of platelets and its receptor is expressed on the platelet surface, it may contribute to the amplification of platelet responses and pathogenesis of cardiovascular disease. The functional and signaling pathways that are involved in IGF-1 modulation of platelet function, however, are presently unknown. Here, I report that IGF-1 stimulation of platelets results in dose-dependent phosphorylation of the IGF receptor in the range of 1 to 100 nM. Phosphorylation of the IGF receptor is rapid and sustained, with maximal phosphorylation reached within 1 minute. Furthermore, IGF-1 stimulates tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) and IRS-2 and their association with the p85 subunit of phosphoinositide-3 kinase (PI3K). IGF-1-stimulated tyrosine phosphorylation of IRS-1 and IRS-2 and subsequent p85 binding is transient and precedes phosphorylation of protein kinase B (PKB) on Ser473. PAR-1-mediated platelet aggregation is potentiated by IGF-1 and this potentiation, together with PKB phosphorylation, is abolished by the PI3Kalpha inhibitors PI-103 and PIK-75. Importantly, the IGF receptor inhibitor NVP-AEW541 and the neutralization antibody alphaIR3 inhibit SFLLRN-stimulated aggregation, implicating IGF-1 in autocrine regulation of platelet function. These results demonstrate that IGF-1 activates the IGF receptor/IRS/PI3K/PKB pathway, and that PI3Kalpha is essential for the potentiatory effect of IGF-1 on platelet responses.

  15. Angiotensin II-induced Akt activation through the epidermal growth factor receptor in vascular smooth muscle cells is mediated by phospholipid metabolites derived by activation of phospholipase D.

    PubMed

    Li, Fang; Malik, Kafait U

    2005-03-01

    Angiotensin II (Ang II) activates cytosolic Ca(2+)-dependent phospholipase A(2) (cPLA(2)), phospholipase D (PLD), p38 mitogen-activated protein kinase (MAPK), epidermal growth factor receptor (EGFR) and Akt in vascular smooth muscle cells (VSMC). This study was conducted to investigate the relationship between Akt activation by Ang II and other signaling molecules in rat VSMC. Ang II-induced Akt phosphorylation was significantly reduced by the PLD inhibitor 1-butanol, but not by its inactive analog 2-butanol, and by brefeldin A, an inhibitor of the PLD cofactor ADP-ribosylation factor, and in cells infected with retrovirus containing PLD(2) siRNA or transfected with PLD(2) antisense but not control LacZ or sense oligonucleotide. Diacylglycerol kinase inhibitor II diminished Ang II-induced and diC8-phosphatidic acid (PA)-increased Akt phosphorylation, suggesting that PLD-dependent Akt activation is mediated by PA. Ang II-induced EGFR phosphorylation was inhibited by 1-butanol and PLD(2) siRNA and also by cPLA(2) siRNA. In addition, the inhibitor of arachidonic acid (AA) metabolism 5,8,11,14-eicosatetraynoic acid (ETYA) reduced both Ang II- and AA-induced EGFR transactivation. Furthermore, ETYA, cPLA(2) antisense, and cPLA(2) siRNA attenuated Ang II-elicited PLD activation. p38 MAPK inhibitor SB202190 [4-(4-flurophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)1H-imidazole] reduced PLD activity and EGFR and Akt phosphorylation elicited by Ang II. Pyrrolidine-1, a cPLA(2) inhibitor, and cPLA(2) siRNA decreased p38 MAPK activity. These data indicate that Ang II-stimulated Akt activity is mediated by cPLA(2)-dependent, p38 MAPK regulated PLD(2) activation and EGFR transactivation. We propose the following scheme of the sequence of events leading to activation of Akt in VSMC by Ang II: Ang II-->cPLA(2)-->AA-->p38 MAPK-->PLD(2)-->PA-->EGFR-->Akt. PMID:15525798

  16. Angiotensin II-induced Akt activation through the epidermal growth factor receptor in vascular smooth muscle cells is mediated by phospholipid metabolites derived by activation of phospholipase D.

    PubMed

    Li, Fang; Malik, Kafait U

    2005-03-01

    Angiotensin II (Ang II) activates cytosolic Ca(2+)-dependent phospholipase A(2) (cPLA(2)), phospholipase D (PLD), p38 mitogen-activated protein kinase (MAPK), epidermal growth factor receptor (EGFR) and Akt in vascular smooth muscle cells (VSMC). This study was conducted to investigate the relationship between Akt activation by Ang II and other signaling molecules in rat VSMC. Ang II-induced Akt phosphorylation was significantly reduced by the PLD inhibitor 1-butanol, but not by its inactive analog 2-butanol, and by brefeldin A, an inhibitor of the PLD cofactor ADP-ribosylation factor, and in cells infected with retrovirus containing PLD(2) siRNA or transfected with PLD(2) antisense but not control LacZ or sense oligonucleotide. Diacylglycerol kinase inhibitor II diminished Ang II-induced and diC8-phosphatidic acid (PA)-increased Akt phosphorylation, suggesting that PLD-dependent Akt activation is mediated by PA. Ang II-induced EGFR phosphorylation was inhibited by 1-butanol and PLD(2) siRNA and also by cPLA(2) siRNA. In addition, the inhibitor of arachidonic acid (AA) metabolism 5,8,11,14-eicosatetraynoic acid (ETYA) reduced both Ang II- and AA-induced EGFR transactivation. Furthermore, ETYA, cPLA(2) antisense, and cPLA(2) siRNA attenuated Ang II-elicited PLD activation. p38 MAPK inhibitor SB202190 [4-(4-flurophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)1H-imidazole] reduced PLD activity and EGFR and Akt phosphorylation elicited by Ang II. Pyrrolidine-1, a cPLA(2) inhibitor, and cPLA(2) siRNA decreased p38 MAPK activity. These data indicate that Ang II-stimulated Akt activity is mediated by cPLA(2)-dependent, p38 MAPK regulated PLD(2) activation and EGFR transactivation. We propose the following scheme of the sequence of events leading to activation of Akt in VSMC by Ang II: Ang II-->cPLA(2)-->AA-->p38 MAPK-->PLD(2)-->PA-->EGFR-->Akt.

  17. Activation of the Ras/Mitogen-Activated Protein Kinase Pathway by Kinase-Defective Epidermal Growth Factor Receptors Results in Cell Survival but Not Proliferation

    PubMed Central

    Walker, Francesca; Kato, Akiko; Gonez, L. Jorge; Hibbs, Margaret L.; Pouliot, Normand; Levitzki, Alexander; Burgess, Antony W.

    1998-01-01

    Signalling by the epidermal growth factor (EGF) receptor (EGFR) has been studied intensively, but for most cell types the analysis is complicated by the fact that EGFR not only homodimerizes but can also form heterodimers with other EGFR family members. Heterodimerization is a particular problem in the study of EGFR mutants, where the true phenotype of the mutants is confounded by the contribution of the heterodimer partner to signal transduction. We have made use of the murine hemopoietic cell line BaF/3, which does not express EGFR family members, to express wild-type (WT) EGFR, three kinase-defective EGFR mutants (V741G, Y740F, and K721R), or a C-terminally truncated EGFR (CT957) and have measured their responses to EGF. We found that under the appropriate conditions EGF can stimulate cell proliferation of BaF/3 cells expressing WT or CT957 EGFRs but not that of cells expressing the kinase-defective mutants. However, EGF promotes the survival of BaF/3 cells expressing either of the kinase-defective receptors (V741G and Y740F), indicating that these receptors can still transmit a survival signal. Analysis of the early signalling events by the WT, V741G, and Y740F mutant EGF receptors indicated that EGF stimulates comparable levels of Shc phosphorylation, Shc–GRB-2 association, and activation of Ras, B-Raf, and Erk-1. Blocking the mitogen-activated protein kinase (MAPK) signalling pathway with the specific inhibitor PD98059 abrogates completely the EGF-dependent survival of cells expressing the kinase-defective EGFR mutants but has no effect on the EGF-dependent proliferation mediated by WT and CT957 EGFRs. Similarly, the Src family kinase inhibitor PP1 abrogates EGF-dependent survival without affecting proliferation. However blocking phosphatidylinositol-3-kinase or JAK-2 kinase with specific inhibitors does arrest growth factor-dependent cell proliferation. Thus, EGFR-mediated mitogenic signalling in BaF/3 cells requires an intact EGFR tyrosine kinase activity

  18. Amelioration of Diabetic Mouse Nephropathy by Catalpol Correlates with Down-Regulation of Grb10 Expression and Activation of Insulin-Like Growth Factor 1 / Insulin-Like Growth Factor 1 Receptor Signaling

    PubMed Central

    Yang, Shasha; Deng, Huacong; Zhang, Qunzhou; Xie, Jing; Zeng, Hui; Jin, Xiaolong; Ling, Zixi; Shan, Qiaoyun; Liu, Momo; Ma, Yuefei; Tang, Juan; Wei, Qianping

    2016-01-01

    Growth factor receptor-bound protein 10 (Grb10) is an adaptor protein that can negatively regulate the insulin-like growth factor 1 receptor (IGF-1R). The IGF1-1R pathway is critical for cell growth and apoptosis and has been implicated in kidney diseases; however, it is still unknown whether Grb10 expression is up-regulated and plays a role in diabetic nephropathy. Catalpol, a major active ingredient of a traditional Chinese medicine, Rehmannia, has been reported to possess anti-inflammatory and anti-aging activities and then used to treat diabetes. Herein, we aimed to assess the therapeutic effect of catalpol on a mouse model diabetic nephropathy and the potential role of Grb10 in the pathogenesis of this diabetes-associated complication. Our results showed that catalpol treatment improved diabetes-associated impaired renal functions and ameliorated pathological changes in kidneys of diabetic mice. We also found that Grb10 expression was significantly elevated in kidneys of diabetic mice as compared with that in non-diabetic mice, while treatment with catalpol significantly abrogated the elevated Grb10 expression in diabetic kidneys. On the contrary, IGF-1 mRNA levels and IGF-1R phosphorylation were significantly higher in kidneys of catalpol-treated diabetic mice than those in non-treated diabetic mice. Our results suggest that elevated Grb10 expression may play an important role in the pathogenesis of diabetic nephropathy through suppressing IGF-1/IGF-1R signaling pathway, which might be a potential molecular target of catalpol for the treatment of this diabetic complication. PMID:26986757

  19. Role of the 6-20 disulfide bridge in the structure and activity of epidermal growth factor.

    PubMed Central

    Barnham, K. J.; Torres, A. M.; Alewood, D.; Alewood, P. F.; Domagala, T.; Nice, E. C.; Norton, R. S.

    1998-01-01

    Two synthetic analogues of murine epidermal growth factor, [Abu6, 20] mEGF4-48 (where Abu denotes amino-butyric acid) and [G1, M3, K21, H40] mEGF1-48, have been investigated by NMR spectroscopy. [Abu6, 20] mEGF4-48 was designed to determine the contribution of the 6-20 disulfide bridge to the structure and function of mEGF. The overall structure of this analogue was similar to that of native mEGF, indicating that the loss of the 6-20 disulfide bridge did not affect the global fold of the molecule. Significant structural differences were observed near the N-terminus, however, with the direction of the polypeptide chain between residues four and nine being altered such that these residues were now located on the opposite face of the main beta-sheet from their position in native mEGF. Thermal denaturation experiments also showed that the structure of [Abu6, 20] mEGF4-48 was less stable than that of mEGF. Removal of this disulfide bridge resulted in a significant loss of both mitogenic activity in Balb/c 3T3 cells and receptor binding on A431 cells compared with native mEGF and mEGF4-48, implying that the structural changes in [Abu6, 20] mEGF4-48, although limited to the N-terminus, were sufficient to interfere with receptor binding. The loss of binding affinity probably arose mainly from steric interactions of the dislocated N-terminal region with part of the receptor binding surface of EGF. [G1, M3, K21, H40] mEGF1-48 was also synthesized in order to compare the synthetic polypeptide with the corresponding product of recombinant expression. Its mitogenic activity in Balb/c 3T3 cells was similar to that of native mEGF and analysis of its 1H chemical shifts suggested that its structure was also very similar to native. PMID:10082370

  20. The activation of fibroblast growth factors (FGFs) by glycosaminoglycans: influence of the sulfation pattern on the biological activity of FGF-1.

    PubMed

    Angulo, Jesús; Ojeda, Rafael; de Paz, José-Luis; Lucas, Ricardo; Nieto, Pedro M; Lozano, Rosa M; Redondo-Horcajo, Mariano; Giménez-Gallego, Guillermo; Martín-Lomas, Manuel

    2004-01-01

    Six synthetic heparin-like oligosaccharides have been used to investigate the effect of the oligosaccharide sulfation pattern on the stimulation of acidic fibroblast growth factor (FGF-1) induced mitogenesis signaling and the biological significance of FGF-1 trans dimerization in the FGF-1 activation process. It has been found that some molecules with a sulfation pattern that does not contain the internal trisaccharide motif, which has been proposed for high affinity for FGF-1, stimulate FGF-1 more efficiently than those with the structure of the regular region of heparin. In contrast to regular region oligosaccharides, in which the sulfate groups are distributed on both sides of their helical three-dimensional structures, the molecules containing this particular sulfation pattern display the sulfate groups only on one side of the helix. These results and the fact that these oligosaccharides do not promote FGF-1 dimerization according to sedimentation-equilibrium analysis, confirm the importance of negative-charge distribution in the activation process and strongly suggest that FGF dimerization is not a general and absolute requirement for biological activity. PMID:14695513

  1. The activation of fibroblast growth factors (FGFs) by glycosaminoglycans: influence of the sulfation pattern on the biological activity of FGF-1.

    PubMed

    Angulo, Jesús; Ojeda, Rafael; de Paz, José-Luis; Lucas, Ricardo; Nieto, Pedro M; Lozano, Rosa M; Redondo-Horcajo, Mariano; Giménez-Gallego, Guillermo; Martín-Lomas, Manuel

    2004-01-01

    Six synthetic heparin-like oligosaccharides have been used to investigate the effect of the oligosaccharide sulfation pattern on the stimulation of acidic fibroblast growth factor (FGF-1) induced mitogenesis signaling and the biological significance of FGF-1 trans dimerization in the FGF-1 activation process. It has been found that some molecules with a sulfation pattern that does not contain the internal trisaccharide motif, which has been proposed for high affinity for FGF-1, stimulate FGF-1 more efficiently than those with the structure of the regular region of heparin. In contrast to regular region oligosaccharides, in which the sulfate groups are distributed on both sides of their helical three-dimensional structures, the molecules containing this particular sulfation pattern display the sulfate groups only on one side of the helix. These results and the fact that these oligosaccharides do not promote FGF-1 dimerization according to sedimentation-equilibrium analysis, confirm the importance of negative-charge distribution in the activation process and strongly suggest that FGF dimerization is not a general and absolute requirement for biological activity.

  2. Measles virus C protein suppresses gamma-activated factor formation and virus-induced cell growth arrest

    SciTech Connect

    Yokota, Shin-ichi; Okabayashi, Tamaki; Fujii, Nobuhiro

    2011-05-25

    Measles virus (MeV) produces two accessory proteins, V and C, from the P gene. These accessory proteins have been reported to contribute to efficient virus proliferation through the modulation of host cell events. Our previous paper described that Vero cell-adapted strains of MeV led host cells to growth arrest through the upregulation of interferon regulatory factor 1 (IRF-1), and wild strains did not. In the present study, we found that C protein expression levels varied among MeV strains in infected SiHa cells. C protein levels were inversely correlated with IRF-1 expression levels and with cell growth arrest. Forced expression of C protein released cells from growth arrest. C-deficient recombinant virus efficiently upregulated IRF-1 and caused growth arrest more efficiently than the wild-type virus. C protein preferentially bound to phosphorylated STAT1 and suppressed STAT1 dimer formation. We conclude that MeV C protein suppresses IFN-{gamma} signaling pathway via inhibition of phosphorylated STAT1 dimerization.

  3. Hepatocyte growth factor (HGF) enhances cardiac commitment of differentiating embryonic stem cells by activating PI3 kinase

    SciTech Connect

    Roggia, Cristiana; Ukena, Christian; Boehm, Michael; Kilter, Heiko . E-mail: kilter@med-in.uni-saarland.de

    2007-03-10

    Hepatocyte growth factor (HGF) is a pleiotropic cytokine promoting proliferation, migration and survival in several cell types. HGF and its cognate receptor c-Met are expressed in cardiac cells during early cardiogenesis, but data concerning its role in cardiac differentiation of embryonic stem cells (ESCs) and the underlying molecular mechanisms involved are limited. In the present study we show that HGF significantly increases the number of beating embryoid bodies of differentiating ESCs without affecting beating frequency. Furthermore, HGF up-regulates the expression of the cardiac-specific transcription factors Nkx 2.5 and GATA-4 and of markers of differentiated cardiomyocytes, i.e. {alpha}-MHC, {beta}-MHC, ANF, MLC2v and Troponin T. The HGF-induced increase in Nkx 2.5 expression was inhibited by co-treatment with the PI3 kinase inhibitors Wortmannin and LY294002, but not by its inactive homolog LY303511, suggesting an involvement of the PI3 kinase/Akt pathway in this effect. We conclude that HGF is an important growth factor involved in cardiac differentiation and/or proliferation of ESCs and may therefore be critical for the in vitro generation of pre- or fully differentiated cardiomyocytes as required for clinical use of embryonic stem cells in cardiac diseases.

  4. Transforming growth factor beta 1-responsive element: closely associated binding sites for USF and CCAAT-binding transcription factor-nuclear factor I in the type 1 plasminogen activator inhibitor gene.

    PubMed Central

    Riccio, A; Pedone, P V; Lund, L R; Olesen, T; Olsen, H S; Andreasen, P A

    1992-01-01

    Transforming growth factor beta (TGF-beta) is the name of a group of closely related polypeptides characterized by a multiplicity of effects, including regulation of extracellular proteolysis and turnover of the extracellular matrix. Its cellular mechanism of action is largely unknown. TGF-beta 1 is a strong and fast inducer of type 1 plasminogen activator inhibitor gene transcription. We have identified a TGF-beta 1-responsive element in the 5'-flanking region of the human type 1 plasminogen activator inhibitor gene and shown that it is functional both in its natural context and when fused to a heterologous nonresponsive promoter. Footprinting and gel retardation experiments showed that two different nuclear factors, present in extracts from both TGF-beta 1-treated and nontreated cells, bind to adjacent sequences contained in the responsive unit. A palindromic sequence binds a trans-acting factor(s) of the CCAAT-binding transcription factor-nuclear factor I family. A partially overlapping dyad symmetry interacts with a second protein that much evidence indicates to be USF. USF is a transactivator belonging to the basic helix-loop-helix family of transcription factors. Mutations which abolish the binding of either CCAAT-binding transcription factor-nuclear factor I or USF result in reduction of transcriptional activation upon exposure to TGF-beta 1, thus showing that both elements of the unit are necessary for the TGF-beta 1 response. We discuss the possible relationship of these findings to the complexity of the TGF-beta action. Images PMID:1549130

  5. Insulin-like growth factor 1 and hair growth.

    PubMed

    Su, H Y; Hickford, J G; Bickerstaffe, R; Palmer, B R

    1999-11-01

    Insulin-like growth factor 1 (IGF-1) has been identified as an important growth factor in many biological systems.[1] It shares considerable structural homology with insulin and exerts insulin-like effects on food intake and glucose metabolism. Recently it has been suggested to play a role in regulating cellular proliferation and migration during the development of hair follicles. [2,3] To exert its biological effects, the IGF-1 is required to activate cells by binding to specific cell-surface receptors. The type I IGF receptor (IGF-1R) is the only IGF receptor to have IGF-mediated signaling functions.[1] In circulation, this growth factor mediates endocrine action of growth hormone (GH) on somatic growth and is bound to specific binding proteins (BPs). The latter control IGF transport, efflux from vascular compartments and association with cell surface receptors.[4] In tissues, IGF-1 is produced by mesenchymal type cells and acts in a paracrine and autocrine fashion by binding to the IGF-1R. This binding activates the receptor tyrosine kinase (RTK) that triggers the downstream responses and finally stimulates cell division.[5] IGF-1 may therefore be able to stimulate the proliferation of hair follicle cells through cellular signaling pathways of its receptors. Local infusion of IGF-1 into sheep has been reported to be capable of stimulating protein synthesis in the skin.[6] It may also increase the production of wool keratin. Recently, transgenic mice overexpressing IGF-1 in the skin have been shown to have earlier hair follicle development than controls.[7] In addition, this growth factor plays an important role in many cell types as a survival factor to prevent cell death.[8] This anti-apoptotic function of IGF-1 may be important to the development of follicle cells as follicles undergo a growth cycle where the regressive, catagen phase is apoptosis driven. In this review, the effects of IGF-1 on follicle cell proliferation and differentiation are discussed. In

  6. ZIP4 Regulates Pancreatic Cancer Cell Growth by Activating IL-6/STAT3 Pathway via Zinc Finger Transcription Factor CREB

    PubMed Central

    Zhang, Yuqing; Bharadwaj, Uddalak; Logsdon, Craig D.; Chen, Changyi; Yao, Qizhi; Li, Min

    2010-01-01

    Purpose Recent studies indicate a strong correlation of zinc transporter ZIP4 and pancreatic cancer progression; however, the underlying mechanisms are unclear. We have recently found that ZIP4 is overexpressed in pancreatic cancer. In this study, we investigated the signaling pathway through which ZIP4 regulates pancreatic cancer growth. Experimental Design The expression of cyclin D1, IL-6, and STAT3 in pancreatic cancer xenografts and cells were examined by real time PCR, Bio-Plex cytokine assay, and Western blot, respectively. The activity of CREB is examined by a promoter activity assay. Results Cyclin D1 was significantly increased in the ZIP4 overexpressing MIA PaCa-2 cells (MIA-ZIP4)-injected orthotopic xenografts and was downregulated in the ZIP4 silenced ASPC-1 (ASPC-shZIP4) group. The phosphorylation of signal transducer and activator of transcription 3 (STAT3), an upstream activator of cyclin D1, was increased in MIA-ZIP4 cells, and decreased in ASPC-shZIP4 cells. IL-6, a known upstream activator for STAT3, was also found to be significantly increased in the MIA-ZIP4 cells and xenografts, and decreased in the ASPC-shZIP4 group. Overexpression of ZIP4 led to a 75% increase of IL-6 promoter activity, and caused increased phosphorylation of cAMP response element binding protein (CREB). Conclusions Our study suggest that ZIP4 overexpression causes increased IL-6 transcription via CREB, which in turn activates STAT3, and leads to increased cyclin D1 expression, resulting in increased cell proliferation and tumor progression in pancreatic cancer. These results elucidated a novel pathway in ZIP4-mediated pancreatic cancer growth, and suggest new therapeutic targets including ZIP4, IL-6, and STAT3 in pancreatic cancer treatment. PMID:20160059

  7. Differential effects of retinoic acid and growth factors on osteoblastic markers and CD10/NEP activity in stromal-derived osteoblasts.

    PubMed

    Benayahu, D; Fried, A; Shamay, A; Cunningham, N; Blumberg, S; Wientroub, S

    1994-09-01

    The effects of retinoic acid (RA) on the expression of osteoblastic-related cell markers was examined. A marrow stromal osteogenic cell line, MBA-15, was analyzed by Northern blotting for the expression of bone matrix proteins. These cells constitutively express mRNA encoding for procollagen alpha 2 (I), osteonectin, osteopontin, biglycan, and alkaline phosphatase (ALK-P). Gene expression was unchanged in response to RA triggering for 24 hr. Furthermore, cell growth and enzymatic activities of ALK-P and neutral endopeptidase (CD10/NEP) were studied. These parameters were examined in MBA-15 and clonal populations representing different stages of differentiation. The cell's growth rate was unchanged, while ALK-P activity was greatly increased during the culture period under RA treatment in MBA-15 and in the clonal cell lines examined while CD10/NEP activity displayed a different pattern. MBA-15.4, a preosteoblast cell line, exhibited an inhibition in CD10/NEP activity at the beginning of the culture period, reaching basal level with time. This activity was greatly increased over control level in MBA-15.6, a mature stage of osteoblasts. Furthermore, the response of cell lines to various growth factors was tested subsequent to priming the cultures with RA. A synergistic effect was monitored for ALK-P activity in MBA-15.4 and MBA-15.6 cells under rh-bone morphogenic protein (BMP-2) and purified osteogenin (BMP-3), and an antagonist effect was measured when cells were exposed to transforming growth factor beta (TGF beta). Contrarily, BMP-2 and BMP-3 inhibited the CD10/NEP activity that had remained unchanged following priming of the cell with RA. Insulin-like growth factor I (IGF-I) and basic fibroblast growth factors (bFGF) did not affect either ALK-P nor CD10/NEP activities in both cloned cells. Cellular response to bone-seeking hormone, parathyroid hormone (PTH), and prostaglandin E2 (PGE2) was monitored by activation of intracellular cAMP. Treatment with RA caused a

  8. Collagen regulates transforming growth factor-β receptors of HL-1 cardiomyocytes through activation of stretch and integrin signaling.

    PubMed

    Lu, Yen-Yu; Lin, Yung-Kuo; Kao, Yu-Hsun; Chung, Cheng-Chih; Yeh, Yung-Hsin; Chen, Shih-Ann; Chen, Yi-Jen

    2016-10-01

    The extracellular matrix (ECM) and transforming growth factor-β (TGF)-β are important in cardiac fibrosis, however, the effects of the ECM on TGF‑β signaling remain to be fully elucidated. The aims of the present study were to evaluate the role of collagen in TGF‑β signaling and examine the underlying mechanisms. In the present study, western blot analysis was used to examine TGF‑β signaling in HL‑1 cells treated with and without (control) type I collagen (10 µg/ml), which was co‑administered with either an anti‑β1 integrin antibody (10 µg/ml) or a stretch‑activated channel inhibitor (gadolinium; 50 µM). Cell proliferation and adhesion assays were used to investigate the roles of integrin, mechanical stretch and mitogen‑activated protein kinases (MAPKs) on cell proliferation and adhesion. The type I collagen (10 µg/ml)‑treated HL‑1 cells were incubated with or without anti‑β1 integrin antibody (10 µg/ml), gadolinium (50 µM) or inhibitors of p38 (SB203580; 3 µM), extracellular signal‑regulated kinase (ERK; PD98059; 50 µM) and c‑Jun N‑terminal kinase (JNK; SP600125; 50 µM). Compared with the control cells, the collagen‑treated HL‑1 cells had lower expression levels of type I and type II TGF‑β receptors (TGFβRI and TGFβRII), with an increase in phosphorylated focal adhesion kinase (FAK), p38 and ERK1/2, and a decrease in JNK. Incubation with the anti‑β1 integrin antibody reversed the collagen‑induced downregulation of the expression of TGFβRII and phosphorylated FAK. Gadolinium downregulated the expression levels of TGFβRI and small mothers against decapentaplegic (Smad)2/3, and decreased the levels of phosphorylated p38, ERK1/2 and JNK. In addition, gadolinium reversed the collagen‑induced activation of p38 and ERK1/2. In the presence of gadolinium and anti‑β1 integrin antibody, collagen regulated the expression levels of TGFβRI, TGFβRII and Smad2/3, but did not alter the phosphorylation

  9. Purification and NH2-terminal amino acid sequence of a T-cell-derived lymphokine with growth factor activity for B-cell hybridomas.

    PubMed Central

    Van Snick, J; Cayphas, S; Vink, A; Uyttenhove, C; Coulie, P G; Rubira, M R; Simpson, R J

    1986-01-01

    A T-cell-derived lymphokine was identified by its ability to support the growth of a subset of B-cell hybridomas. Hybrids that failed to survive in the absence of this molecule represented a major proportion of rat-mouse hybridomas but were very rare among mouse-mouse B-cell hybrids. Stable factor-dependent B-cell hybridomas were used to monitor the purification of the growth factor from the supernatant of a clonotypically stimulated mouse helper T-cell clone. Sequential fractionation using gel filtration, anion-exchange chromatography, and reversed-phase HPLC resolved the factor from other B-cell growth factors and yielded a single-chain protein characterized by a major charge (pI = 5-7) and molecular mass (22- to 29-kDa) heterogeneity, probably due to variations in glycosylation. The NH2-terminal amino acid sequence of this protein, which is active on B-cell hybridomas in the 0.1 pM range, showed no significant homology with that of known lymphokines. Because the purified factor also supported the growth and survival in vitro of murine plasmacytomas (to be published elsewhere), it was provisionally designated interleukin-HP1 (where H stands for hybridoma and P stands for plasmacytoma). Images PMID:2948184

  10. Id-1 expression induces androgen-independent prostate cancer cell growth through activation of epidermal growth factor receptor (EGF-R).

    PubMed

    Ling, Ming-Tat; Wang, Xianghong; Lee, Davy T; Tam, P C; Tsao, Sai-Wah; Wong, Yong-Chuan

    2004-04-01

    The failure of prostate cancer treatment is largely due to the development of androgen independence, since the androgen depletion therapy remains the front-line option for this cancer. Previously, we reported that over-expression of the helix-loop-helix protein Id-1 was associated with progression of prostate cancer and ectopic expression of Id-1 induced serum-independent proliferation in prostate cancer cells. In the present study, we investigated if exogenous Id-1 expression in the androgen sensitive LNCaP cells had any effect on androgen-dependent cell growth and studied the molecular mechanisms involved. Using stable Id-1 transfectants, we found that expression of Id-1 was able to reduce androgen-stimulated growth and S phase fraction of the cell cycle in LNCaP cells, indicating that Id-1 may be involved in the development of androgen independence in these cells. The Id-1-induced androgen-independent prostate cancer cell growth was correlated with up-regulation of EGF-R (epidermal growth factor-receptor) and PSA (prostate specific antigen) expression, as confirmed by western blotting analysis and luciferase assays. In contrast, down-regulation of Id-1 in androgen-independent DU145 cells by its antisense oligonucleotides resulted in suppression of EGF-R expression at both transcriptional and protein levels. In addition, the results from immunohistochemistry study showed that Id-1 expression was significantly elevated in hormone refractory prostate cancer tissues when compared with the hormone-dependent tumours. Our results suggest that up-regulation of Id-1 in prostate cancer cells may be one of the mechanisms responsible for developing androgen independence and this process may be regulated through induction of EGF-R expression. Inactivation of Id-1 may provide a potential therapeutic strategy leading to inhibition of androgen-independent prostate cancer cell growth.

  11. The cell-penetrating peptide domain from human heparin-binding epidermal growth factor-like growth factor (HB-EGF) has anti-inflammatory activity in vitro and in vivo

    SciTech Connect

    Lee, Jue-Yeon; Seo, Yoo-Na; Park, Hyun-Jung; Park, Yoon-Jeong; Chung, Chong-Pyoung

    2012-03-23

    Highlights: Black-Right-Pointing-Pointer HBP sequence identified from HB-EGF has cell penetration activity. Black-Right-Pointing-Pointer HBP inhibits the NF-{kappa}B dependent inflammatory responses. Black-Right-Pointing-Pointer HBP directly blocks phosphorylation and degradation of I{kappa}B{alpha}. Black-Right-Pointing-Pointer HBP inhibits nuclear translocation of NF-{kappa}B p65 subunit. -- Abstract: A heparin-binding peptide (HBP) sequence from human heparin-binding epidermal growth factor-like growth factor (HB-EGF) was identified and was shown to exhibit cell penetration activity. This cell penetration induced an anti-inflammatory reaction in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages. HBP penetrated the cell membrane during the 10 min treatment and reduced the LPS-induced production of nitric oxide (NO), inducible nitric oxide synthase (iNOS), and cytokines (TNF-{alpha} and IL-6) in a concentration-dependent manner. Additionally, HBP inhibited the LPS-induced upregulation of cytokines, including TNF-{alpha} and IL-6, and decreased the interstitial infiltration of polymorphonuclear leukocytes in a lung inflammation model. HBP inhibited NF-{kappa}B-dependent inflammatory responses by directly blocking the phosphorylation and degradation of I{kappa}B{alpha} and by subsequently inhibiting the nuclear translocation of the p65 subunit of NF-{kappa}B. Taken together, this novel HBP may be potentially useful candidate for anti-inflammatory treatments and can be combined with other drugs of interest to transport attached molecules into cells.

  12. Inhibition of transforming growth factor-β-activated kinase-1 blocks cancer cell adhesion, invasion, and metastasis

    PubMed Central

    Ray, D M; Myers, P H; Painter, J T; Hoenerhoff, M J; Olden, K; Roberts, J D

    2012-01-01

    Background: Tumour cell metastasis involves cell adhesion and invasion, processes that depend on signal transduction, which can be influenced by the tumour microenvironment. N-6 polyunsaturated fatty acids, found both in the diet and in response to inflammatory responses, are important components of this microenvironment. Methods: We used short hairpin RNA (shRNA) knockdown of TGF-β-activated kinase-1 (TAK1) in human tumour cells to examine its involvement in fatty acid-stimulated cell adhesion and invasion in vitro. An in vivo model of metastasis was developed in which cells, stably expressing firefly luciferase and either a control shRNA or a TAK1-specific shRNA, were injected into the mammary fat pads of mice fed diets, rich in n-6 polyunsaturated fatty acids. Tumour growth and spontaneous metastasis were monitored with in vivo and in situ imaging of bioluminescence. Results: Arachidonic acid activated TAK1 and downstream kinases in MDA-MB-435 breast cancer cells and led to increased adhesion and invasion. Knockdown of TAK1 blocked this activation and inhibited both cell adhesion and invasion in vitro. Tumour growth at the site of injection was not affected by TAK1 knockdown, but both the incidence and extent of metastasis to the lung were significantly reduced in mice injected with TAK1 knockdown cells compared with mice carrying control tumour cells. Conclusion: These data demonstrate the importance of TAK1 signalling in tumour metastasis in vivo and suggest an opportunity for antimetastatic therapies. PMID:22644295

  13. Placenta Growth Factor in Diabetic Wound Healing

    PubMed Central

    Cianfarani, Francesca; Zambruno, Giovanna; Brogelli, Laura; Sera, Francesco; Lacal, Pedro Miguel; Pesce, Maurizio; Capogrossi, Maurizio C.; Failla, Cristina Maria; Napolitano, Monica; Odorisio, Teresa

    2006-01-01

    Reduced microcirculation and diminished expression of growth factors contribute to wound healing impairment in diabetes. Placenta growth factor (PlGF), an angiogenic mediator promoting pathophysiological neovascularization, is expressed during cutaneous wound healing and improves wound closure by enhancing angiogenesis. By using streptozotocin-induced diabetic mice, we here demonstrate that PlGF induction is strongly reduced in diabetic wounds. Diabetic transgenic mice overexpressing PlGF in the skin displayed accelerated wound closure compared with diabetic wild-type littermates. Moreover, diabetic wound treatment with an adenovirus vector expressing the human PlGF gene (AdCMV.PlGF) significantly accelerated the healing process compared with wounds treated with a control vector. The analysis of treated wounds showed that PlGF gene transfer improved granulation tissue formation, maturation, and vascularization, as well as monocytes/macrophages local recruitment. Platelet-derived growth factor, fibroblast growth factor-2, and vascular endothelial growth factor mRNA levels were increased in AdCMV.PlGF-treated wounds, possibly enhancing PlGF-mediated effects. Finally, PlGF treatment stimulated cultured dermal fibroblast migration, pointing to a direct role of PlGF in accelerating granulation tissue maturation. In conclusion, our data indicate that reduced PlGF expression contributes to impaired wound healing in diabetes and that PlGF gene transfer to diabetic wounds exerts therapeutic activity by promoting different aspects of the repair process. PMID:17003476

  14. Acidic fibroblast growth factor and keratinocyte growth factor stimulate fetal rat pulmonary epithelial growth.

    PubMed

    Deterding, R R; Jacoby, C R; Shannon, J M

    1996-10-01

    We have shown that pulmonary epithelial growth and differentiation can occur if pulmonary mesenchyme is replaced with a mixture of growth factors [total growth medium (TGM)] that consists of adult rat bronchoalveolar lavage fluid, insulin, epidermal growth factor (EGF), cholera toxin (CT), acidic fibroblast growth factor (aFGF), and fetal bovine serum. In the present study, we have defined the importance of specific components of TGM. Day 14 fetal rat distal lung epithelium, devoid of mesenchyme, was enrobed in growth factor-depleted Matrigel and cultured for 5 days in various soluble factors. We found that deleting aFGF or CT from TGM significantly reduced DNA synthesis. Epithelial proliferation was not significantly different when keratinocyte growth factor (KGF) replaced aFGF in TGM. KGF, however, required the presence of a basal medium containing CT, insulin, and serum for optimal proliferation. We then added specific growth factors to the basal medium and showed that aFGF and KGF were more potent mitogens than EGF, transforming growth factor-alpha, and hepatocyte growth factor. Additionally, basal medium + KGF also allowed progression to a distal alveolar phenotype. We conclude that aFGF and KGF may be important mediators in epithelial-mesenchymal interactions. PMID:8897895

  15. Salinomycin exerts anti-angiogenic and anti-tumorigenic activities by inhibiting vascular endothelial growth factor receptor 2-mediated angiogenesis.

    PubMed

    Li, Tao; Liu, Xiaoxia; Shen, Qin; Yang, Wenjun; Huo, Zhenghao; Liu, Qilun; Jiao, Haiyan; Chen, Jing

    2016-05-01

    Anti-angiogenesis targeting VEGFR2 has been an attractive strategy for cancer therapy for its role in promoting cancer growth and metastasis. However, the currently available drugs have unexpected side effects. Therefore, development of novel VEGFR2 inhibitors with less toxicity would be of great value. In this study, we describe a novel and safely VEGFR2 inhibitor, Salinomycin (Sal), which was screened from the drug libraries of Food and Drug Administration (FDA) and prohibited the binding of the ATP at its binding pocket of VEGFR2 using molecular docking model. Sal could interfere a series of VEGF-induced angiogenesis processes including proliferation, migration, and tube formation in HUVECS in vitro. Matrigel plug model demonstrated Sal strongly inhibited angiogenesis in vivo. We found that Sal significantly decreased VEGF-induced phosphorylation of VEGFR2 and its downstream STAT3 in dose- and time-dependent manner in HUVECs. Besides, Sal could directly reduce the cell viability and induce apoptosis in SGC-7901 cancer cells in vitro. Sal inhibited constitutive STAT3 activation by blocking its DNA binding and reduced various gene products including Bcl-2, Bcl-xL and VEGF both at mRNA and protein levels. Intra-peritoneal injection of Sal at doses of 3 and 5 mg/kg/day markedly suppressed human gastric cancer xenografts angiogenesis and growth without causing obvious toxicities. Taken together, Sal inhibits tumor angiogenesis and growth of gastric cancer; our results reveal unique characteristics of Sal as a promising anticancer drug candidate. PMID:27058891

  16. Salinomycin exerts anti-angiogenic and anti-tumorigenic activities by inhibiting vascular endothelial growth factor receptor 2-mediated angiogenesis

    PubMed Central

    Shen, Qin; Yang, Wenjun; Huo, Zhenghao; Liu, Qilun; Jiao, Haiyan; Chen, Jing

    2016-01-01

    Anti-angiogenesis targeting VEGFR2 has been an attractive strategy for cancer therapy for its role in promoting cancer growth and metastasis. However, the currently available drugs have unexpected side effects. Therefore, development of novel VEGFR2 inhibitors with less toxicity would be of great value. In this study, we describe a novel and safely VEGFR2 inhibitor, Salinomycin (Sal), which was screened from the drug libraries of Food and Drug Administration (FDA) and prohibited the binding of the ATP at its binding pocket of VEGFR2 using molecular docking model. Sal could interfere a series of VEGF-induced angiogenesis processes including proliferation, migration, and tube formation in HUVECS in vitro. Matrigel plug model demonstrated Sal strongly inhibited angiogenesis in vivo. We found that Sal significantly decreased VEGF-induced phosphorylation of VEGFR2 and its downstream STAT3 in dose- and time-dependent manner in HUVECs. Besides, Sal could directly reduce the cell viability and induce apoptosis in SGC-7901 cancer cells in vitro. Sal inhibited constitutive STAT3 activation by blocking its DNA binding and reduced various gene products including Bcl-2, Bcl-xL and VEGF both at mRNA and protein levels. Intra-peritoneal injection of Sal at doses of 3 and 5 mg/kg/day markedly suppressed human gastric cancer xenografts angiogenesis and growth without causing obvious toxicities. Taken together, Sal inhibits tumor angiogenesis and growth of gastric cancer; our results reveal unique characteristics of Sal as a promising anticancer drug candidate. PMID:27058891

  17. Growth hormone activation of human monocytes for superoxide production but not tumor necrosis factor production, cell adherence, or action against Mycobacterium tuberculosis.

    PubMed Central

    Warwick-Davies, J; Lowrie, D B; Cole, P J

    1995-01-01

    We have previously demonstrated that growth hormone (GH) is a human macrophage-activating factor which primes monocytes for enhanced production of H2O2 in vitro. This report extends our observations to other monocyte functions relevant to infection. We find that GH also primes monocytes for O2- production, to a degree similar to the effect of gamma interferon. Neither macrophage-activating factor alone stimulates monocytes to release bioactive tumor necrosis factor. However, GH, unlike gamma interferon, does not synergize with endotoxin for enhanced tumor necrosis factor production. In further contrast, GH does not alter monocyte adherence or morphology, while phagocytosis and killing of Mycobacterium tuberculosis by GH-treated monocytes are also unaffected. Therefore, despite the multiplicity of the effects of GH on the immune system in vivo, its effects on human monocytes in vitro appear to be limited to priming for the release of reactive oxygen intermediates. PMID:7591064

  18. Transforming growth factor-beta 1 and fibroblast growth factors in rat growth plate.

    PubMed

    Jingushi, S; Scully, S P; Joyce, M E; Sugioka, Y; Bolander, M E

    1995-09-01

    Chondrocytes in the growth plate progress in an orderly fashion from resting through proliferating to hypertrophic cells. In the region of hypertrophic chondrocytes, the cartilage is invaded by capillary loops and endochondral ossification is initiated. It is currently believed that growth factors may regulate the proliferation and maturation of chondrocytes and the synthesis of extracellular matrix in the growth plate. The ordered sequence of proliferation and differentiation observed in the growth plate provides a unique opportunity to study the role of acidic fibroblast growth factor, basic fibroblast growth factor, and transforming growth factor-beta 1 in the regulation of these processes. In this study, expression of the mRNA of these growth factors was examined using total RNA extracted from the physis and epiphysis of rat tibias. Transforming growth factor-beta 1 mRNA was detected by Northern hybridization. Expression of the genes encoding acidic and basic fibroblast growth factors was demonstrated by polymerase chain reaction amplification. In addition, using polyclonal antibodies against these growth factors, we localized them by immunohistochemical analysis. Strong intracellular staining with a predominantly nuclear pattern was observed in chondrocytes from the proliferating and upper hypertrophic zones. In contrast, chondrocytes in the resting zone stained only faintly for the presence of these growth factors. Some chondrocytes in the resting zone adjacent to the proliferating zone stained with these antibodies, and the antibodies also stained cells in the zone of Ranvier, which regulates latitudinal bone growth. Lastly, the location of transforming growth factor-beta 1 was examined further with use of a polyclonal antipeptide antibody specific for its extracellular epitope.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7472755

  19. Tyrosine dephosphorylation enhances the therapeutic target activity of epidermal growth factor receptor (EGFR) by disrupting its interaction with estrogen receptor (ER).

    PubMed

    Ma, Shao; Yin, Ning; Qi, Xiaomei; Pfister, Sandra L; Zhang, Mei-Jie; Ma, Rong; Chen, Guan

    2015-05-30

    Protein-protein interactions can increase or decrease its therapeutic target activity and the determining factors involved, however, are largely unknown. Here, we report that tyrosine-dephosphorylation of epidermal growth factor receptor (EGFR) increases its therapeutic target activity by disrupting its interaction with estrogen receptor (ER). Protein tyrosine phosphatase H1 (PTPH1) dephosphorylates the tyrosine kinase EGFR, disrupts its interaction with the nuclear receptor ER, and increases breast cancer sensitivity to small molecule tyrosine kinase inhibitors (TKIs). These effects require PTPH1 catalytic activity and its interaction with EGFR, suggesting that the phosphatase may increase the sensitivity by dephosphorylating EGFR leading to its dissociation with ER. Consistent with this notion, a nuclear-localization defective ER has a higher EGFR-binding activity and confers the resistance to TKI-induced growth inhibition. Additional analysis show that PTPH1 stabilizes EGFR, stimulates the membranous EGFR accumulation, and enhances the growth-inhibitory activity of a combination therapy of TKIs with an anti-estrogen. Since EGFR and ER both are substrates for PTPH1 in vitro and in intact cells, these results indicate that an inhibitory EGFR-ER protein complex can be switched off through a competitive enzyme-substrate binding. Our results would have important implications for the treatment of breast cancer with targeted therapeutics.

  20. Tyrosine dephosphorylation enhances the therapeutic target activity of epidermal growth factor receptor (EGFR) by disrupting its interaction with estrogen receptor (ER)

    PubMed Central

    Ma, Shao; Yin, Ning; Qi, Xiaomei; Pfister, Sandra L.; Zhang, Mei-Jie; Ma, Rong; Chen, Guan

    2015-01-01

    Protein-protein interactions can increase or decrease its therapeutic target activity and the determining factors involved, however, are largely unknown. Here, we report that tyrosine-dephosphorylation of epidermal growth factor receptor (EGFR) increases its therapeutic target activity by disrupting its interaction with estrogen receptor (ER). Protein tyrosine phosphatase H1 (PTPH1) dephosphorylates the tyrosine kinase EGFR, disrupts its interaction with the nuclear receptor ER, and increases breast cancer sensitivity to small molecule tyrosine kinase inhibitors (TKIs). These effects require PTPH1 catalytic activity and its interaction with EGFR, suggesting that the phosphatase may increase the sensitivity by dephosphorylating EGFR leading to its dissociation with ER. Consistent with this notion, a nuclear-localization defective ER has a higher EGFR-binding activity and confers the resistance to TKI-induced growth inhibition. Additional analysis show that PTPH1 stabilizes EGFR, stimulates the membranous EGFR accumulation, and enhances the growth-inhibitory activity of a combination therapy of TKIs with an anti-estrogen. Since EGFR and ER both are substrates for PTPH1 in vitro and in intact cells, these results indicate that an inhibitory EGFR-ER protein complex can be switched off through a competitive enzyme-substrate binding. Our results would have important implications for the treatment of breast cancer with targeted therapeutics. PMID:26079946

  1. Fermented milk containing Lactobacillus GG alleviated DSS-induced colitis in mice and activated epidermal growth factor receptor and Akt signaling in intestinal epithelial cells.

    PubMed

    Yoda, Kazutoyo; He, Fang; Miyazawa, Kenji; Hiramatsu, Masaru; Yan, Fang

    2012-01-01

    Lactobacillus rhamnosus GG was assessed for its ability to alleviate DSS-induced colitis in mice and activate epidermal growth factor receptor and Akt signaling in intestinal epithelial cells. In this study mice were treated with DSS to induce colitis and they were given Lactobacillus GG fermented milk to assess the effect of probiotic on colitis. Lactobacillus GG fermented milk significantly reduced the colitis associated changes suggesting a protective effect against DSS induced colitis.

  2. Production of biologically active IgG hinge-tag soluble epidermal growth factor receptors (ErbB).

    PubMed

    Otani, Takayuki; Hashizume, Toshihiro; Nagaoka, Tadahiro; Fukuda, Tomoko; Tang, Careen K; Salomon, David S; Seno, Masaharu

    2010-03-01

    The extracellular domains (ECD) of epidermal growth factor receptors, ErbB1, 2, 3 and 4, were designed as soluble dimeric forms. Each ECD was fused to a short hinge region derived from IgG, such that the stable dimer could be formed with disulfide bridges. This hinge-tagged design minimized the molecular weight to approximately 50% of the conventional Fc-fusion design without an Fc domain of IgG. The refolded dimers could be easily analyzed and characterized by SDS-PAGE. Hinge-tagged soluble ErbBs demonstrated significant affinity for betacellulin and heregulin. The IgG hinge-tag should be a simple method to design soluble dimers that would be useful for high throughput screening of ligands, antagonists or derivatives.

  3. Regulation of connective tissue growth factor activity in cultured rat mesangial cells and its expression in experimental diabetic glomerulosclerosis.

    PubMed

    Riser, B L; Denichilo, M; Cortes, P; Baker, C; Grondin, J M; Yee, J; Narins, R G

    2000-01-01

    Connective tissue growth factor (CTGF) is a peptide secreted by cultured endothelial cells and fibroblasts when stimulated by transforming growth factor-beta (TGF-beta), and is overexpressed during fibrotic processes in coronary arteries and in skin. To determine whether CTGF is implicated in the pathogenesis of diabetic glomerulosclerosis, cultured rat mesangial cells (MC) as well as kidney cortex and microdissected glomeruli were examined from obese, diabetic db/db mice and their normal counterparts. Exposure of MC to recombinant human CTGF significantly increased fibronectin and collagen type I production. Furthermore, unstimulated MC expressed low levels of CTGF message and secreted minimal amounts of CTGF protein (36 to 38 kD) into the media. However, sodium heparin treatment resulted in a greater than fourfold increase in media-associated CTGF, suggesting that the majority of CTGF produced was cell- or matrix-bound. Exposure of MC to TGF-beta, increased glucose concentrations, or cyclic mechanical strain, all causal factors in diabetic glomerulosclerosis, markedly induced the expression of CTGF transcripts, while recombinant human CTGF was able to autoinduce its own expression. TGF-, and high glucose, but not mechanical strain, stimulated the concomitant secretion of CTGF protein, the former also inducing abundant quantities of a small molecular weight form of CTGF (18 kD) containing the heparin-binding domain. The induction of CTGF protein by a high glucose concentration was mediated by TGF-beta, since a TGF-beta-neutralizing antibody blocked this stimulation. In vivo studies using quantitative reverse transcription-PCR demonstrated that although CTGF transcripts were low in the glomeruli of control mice, expression was increased 28-fold after approximately 3.5 mo of diabetes. This change occurred early in the course of diabetic nephropathy when mesangial expansion was mild, and interstitial disease and proteinuria were absent. A substantially reduced

  4. Epidermal growth factor and growth in vivo

    SciTech Connect

    Rhodes, J.A.

    1986-01-01

    Epidermal growth factor (EGF) causes a dose-dependent thickening of the epidermis in suckling mice. The cellular mechanisms underlying this thickening were analyzed by measuring the effect of EGF on the cell-cycle. Neonatal mice were given daily injections of either 2ug EGF/g body weight/day or an equivalent volume of saline, and on the seventh day received a single injection of /sup 3/H-thymidine. At various times the mice were perfused with fixative; 1um sections of skin were stained with a modification of Harris' hematoxylin and were autoradiographed. The sections were analyzed using three methods based on the dependence on time after injection of /sup 3/H-thymidine of: frequency of labelled mitoses, labelling index, and reciprocal grains/nucleus. It was found that EGF caused a two-fold increase in the cell production rate. The effect of exogenous EGF on the morphology of gastric mucosa and incisors of suckling mice was also studied. The gastric mucosa appeared thicker in EGF-treated animals, but the effect was not statistically significant. In contrast to its effect on epidermis and gastric mucosa, EGF caused a significant, dose-dependent decrease in the size of the incisors. Because the mouse submandibular salivary gland is the major source of EGF the effect of sialoadenectomy on female reproductive functions was examined. Ablation of the submandibular gland had no effect on: length of estrus cycle, ability of the female to produce litters, length of the gestation period, litter size, and weight of the litter at birth. There was also no effect on survival of the offspring or on age at which the eyelids separated.

  5. EGCG inhibits activation of the insulin-like growth factor-1 receptor in human colon cancer cells

    SciTech Connect

    Shimizu, Masahito; Deguchi, Atsuko; Hara, Yukihiko; Moriwaki, Hisataka; Weinstein, I. Bernard . E-mail: ibw1@columbia.edu

    2005-09-02

    The IGF/IGF-1R system, which includes the IGF, IGF-1R, and IGFBPs proteins, plays an important role in the development and growth of colorectal cancer. We previously reported that in the HT29 human colon cancer cell line EGCG, the major biologically active component of green tea, inhibits activation of the RTKs EGFR, HER2, and HER3, and that this is associated with inhibition of multiple downstream signaling pathways. Since IGF-1R is also a RTK, in this study we examined the effects of EGCG on the activity of IGF/IGF-1R system in human colon cancer cells. We found that the colon cancer cell lines Caco2, HT29, SW837, and SW480 express high levels of the IGF-1R receptor, and that both SW837 and SW480 cells display constitutive activation of this receptor. Treatment of SW837 cells with 20 {mu}g/ml of EGCG (the IC{sub 50} concentration for growth inhibition) caused within 6 h a decrease in the phosphorylated (i.e., activated) form of the IGF-1R protein. At 12 h, there was a decrease in the levels of both IGF-1 protein and mRNA and within 3-6 h there was an increase in the levels of both IGFBP-3 protein and mRNA. The increased expression of the latter protein was sustained for at least 48 h. When SW837 cells were treated with EGCG for a longer time, i.e., 96 h, a very low concentration (1.0 {mu}g/ml) of EGCG also caused inhibition of activation of IGF-1R, a decrease in the IGF-1 protein, and an increase in the IGFBP-3 protein. EGCG also caused a decrease in the levels of mRNAs that encode MMPs-7 and -9, proteins that proteolyze IGFBP-3. In addition, treatment with EGCG caused a transient increase in the expression of TGF-{beta}2, an inducer of IGFBP-3 expression. These findings expand the roles of EGCG as an inhibitor of critical RTKs involved in cell proliferation, providing further evidence that EGCG and related compounds may be useful in the chemoprevention or treatment of colorectal cancer.

  6. The cAMP Response Element Binding protein (CREB) is activated by Insulin-like Growth Factor-1 (IGF-1) and regulates myostatin gene expression in skeletal myoblast

    SciTech Connect

    Zuloaga, R.; Fuentes, E.N.; Molina, A.; Valdés, J.A.

    2013-10-18

    Highlights: •IGF-1 induces the activation of CREB via IGF-1R/PI3K/PLC signaling pathway. •Calcium dependent signaling pathways regulate myostatin gene expression. •IGF-1 regulates myostatin gene expression via CREB transcription in skeletal myoblast. -- Abstract: Myostatin, a member of the Transforming Growth Factor beta (TGF-β) superfamily, plays an important role as a negative regulator of skeletal muscle growth and differentiation. We have previously reported that IGF-1 induces a transient myostatin mRNA expression, through the activation of the Nuclear Factor of Activated T cells (NFAT) in an IP{sub 3}/calcium-dependent manner. Here we examined the activation of CREB transcription factor as downstream targets of IGF-1 during myoblast differentiation and its role as a regulator of myostatin gene expression. In cultured skeletal myoblast, IGF-1 induced the phosphorylation and transcriptional activation of CREB via IGF-1 Receptor/Phosphatidylinositol 3-Kinase (PI3K)/Phospholipase C gamma (PLC γ), signaling pathways. Also, IGF-1 induced calcium-dependent molecules such as Calmodulin Kinase II (CaMK II), Extracellular signal-regulated Kinases (ERK), Protein Kinase C (PKC). Additionally, we examined myostatin mRNA levels and myostatin promoter activity in differentiated myoblasts stimulated with IGF-1. We found a significant increase in mRNA contents of myostatin and its reporter activity after treatment with IGF-1. The expression of myostatin in differentiated myoblast was downregulated by the transfection of siRNA–CREB and by pharmacological inhibitors of the signaling pathways involved in CREB activation. By using pharmacological and genetic approaches together these data demonstrate that IGF-1 regulates the myostatin gene expression via CREB transcription factor during muscle cell differentiation.

  7. Relationships Between RNA Polymerase II Activity and Spt Elongation Factors to Spt- Phenotype and Growth in Saccharomyces cerevisiae

    PubMed Central

    Cui, Ping; Jin, Huiyan; Vutukuru, Manjula Ramya; Kaplan, Craig D.

    2016-01-01

    The interplay between adjacent transcription units can result in transcription-dependent alterations in chromatin structure or recruitment of factors that determine transcription outcomes, including the generation of intragenic or other cryptic transcripts derived from cryptic promoters. Mutations in a number of genes in Saccharomyces cerevisiae confer both cryptic intragenic transcription and the Suppressor of Ty (Spt-) phenotype for the lys2-128∂ allele of the LYS2 gene. Mutants that suppress lys2-128∂ allow transcription from a normally inactive Ty1 ∂ promoter, conferring a LYS+ phenotype. The arrangement of transcription units at lys2-128∂ is reminiscent of genes containing cryptic promoters within their open reading frames. We set out to examine the relationship between RNA Polymerase II (Pol II) activity, functions of Spt elongation factors, and cryptic transcription because of the previous observation that increased-activity Pol II alleles confer an Spt- phenotype. We identify both cooperating and antagonistic genetic interactions between Pol II alleles and alleles of elongation factors SPT4, SPT5, and SPT6. We find that cryptic transcription at FLO8 and STE11 is distinct from that at lys2-128∂, though all show sensitivity to reduction in Pol II activity, especially the expression of lys2-128∂ found in Spt- mutants. We determine that the lys2-128∂ Spt- phenotypes for spt6-1004 and increased activity rpo21/rpb1 alleles each require transcription from the LYS2 promoter. Furthermore, we identify the Ty1 transcription start site (TSS) within the ∂ element as the position of Spt- transcription in tested Spt- mutants. PMID:27261007

  8. Relationships Between RNA Polymerase II Activity and Spt Elongation Factors to Spt- Phenotype and Growth in Saccharomyces cerevisiae.

    PubMed

    Cui, Ping; Jin, Huiyan; Vutukuru, Manjula Ramya; Kaplan, Craig D

    2016-08-09

    The interplay between adjacent transcription units can result in transcription-dependent alterations in chromatin structure or recruitment of factors that determine transcription outcomes, including the generation of intragenic or other cryptic transcripts derived from cryptic promoters. Mutations in a number of genes in Saccharomyces cerevisiae confer both cryptic intragenic transcription and the Suppressor of Ty (Spt(-)) phenotype for the lys2-128∂ allele of the LYS2 gene. Mutants that suppress lys2-128∂ allow transcription from a normally inactive Ty1 ∂ promoter, conferring a LYS(+) phenotype. The arrangement of transcription units at lys2-128∂ is reminiscent of genes containing cryptic promoters within their open reading frames. We set out to examine the relationship between RNA Polymerase II (Pol II) activity, functions of Spt elongation factors, and cryptic transcription because of the previous observation that increased-activity Pol II alleles confer an Spt(-) phenotype. We identify both cooperating and antagonistic genetic interactions between Pol II alleles and alleles of elongation factors SPT4, SPT5, and SPT6 We find that cryptic transcription at FLO8 and STE11 is distinct from that at lys2-128∂, though all show sensitivity to reduction in Pol II activity, especially the expression of lys2-128∂ found in Spt(-) mutants. We determine that the lys2-128∂ Spt(-) phenotypes for spt6-1004 and increased activity rpo21/rpb1 alleles each require transcription from the LYS2 promoter. Furthermore, we identify the Ty1 transcription start site (TSS) within the ∂ element as the position of Spt(-) transcription in tested Spt(-) mutants.

  9. Epidermal Growth Factor and Intestinal Barrier Function.

    PubMed

    Tang, Xiaopeng; Liu, Hu; Yang, Shufen; Li, Zuohua; Zhong, Jinfeng; Fang, Rejun

    2016-01-01

    Epidermal growth factor (EGF) is a 53-amino acid peptide that plays an important role in regulating cell growth, survival, migration, apoptosis, proliferation, and differentiation. In addition, EGF has been established to be an effective intestinal regulator helping to protect intestinal barrier integrity, which was essential for the absorption of nutrients and health in humans and animals. Several researches have demonstrated that EGF via binding to the EGF receptor and subsequent activation of Ras/MAPK, PI3K/AKT, PLC-γ/PKC, and STATS signal pathways regulates intestinal barrier function. In this review, the relationship between epidermal growth factor and intestinal development and intestinal barrier is described, to provide a better understanding of the effects of EGF on intestine development and health. PMID:27524860

  10. Epidermal Growth Factor and Intestinal Barrier Function

    PubMed Central

    Liu, Hu; Yang, Shufen; Li, Zuohua; Zhong, Jinfeng

    2016-01-01

    Epidermal growth factor (EGF) is a 53-amino acid peptide that plays an important role in regulating cell growth, survival, migration, apoptosis, proliferation, and differentiation. In addition, EGF has been established to be an effective intestinal regulator helping to protect intestinal barrier integrity, which was essential for the absorption of nutrients and health in humans and animals. Several researches have demonstrated that EGF via binding to the EGF receptor and subsequent activation of Ras/MAPK, PI3K/AKT, PLC-γ/PKC, and STATS signal pathways regulates intestinal barrier function. In this review, the relationship between epidermal growth factor and intestinal development and intestinal barrier is described, to provide a better understanding of the effects of EGF on intestine development and health. PMID:27524860

  11. A comparison of the effects of unfractionated heparin, dalteparin and danaparoid on vascular endothelial growth factor-induced tumour angiogenesis and heparanase activity.

    PubMed

    Takahashi, Hidenori; Ebihara, Satoru; Okazaki, Tatsuma; Asada, Masanori; Sasaki, Hidetada; Yamaya, Mutsuo

    2005-10-01

    Disseminated intravascular coagulation (DIC) is the most common complication of solid tumours. In this study, the effectiveness of three polysaccharide anticoagulants (PSAs), at therapeutic doses, at inhibiting solid tumour growth was investigated. Mice with tumour xenografts were subcutaneously injected with either unfractionated heparin (UFH; 200 units kg(-1) day(-1)), dalteparin (75 units kg(-1) day(-1)) or danaparoid (50 units kg(-1) day(-1)). At these concentrations, these PSAs are equieffective at inhibiting blood coagulation activated factor X. In mice with Lewis lung carcinoma (LLC) tumours dalteparin and, to a lesser extent, UFH inhibited both tumour growth and angiogenesis, whereas danaparoid did not. In contrast, in mice with KLN205 tumours, all the PSAs inhibited tumour growth and angiogenesis. All the PSAs significantly inhibited proliferation, migration of endothelial cells and vessel formation in matrigel plugs containing vascular endothelial growth factor (VEGF) and there were no significant differences between these effects of the PSAs. The PSAs had no effect on endothelial cell tubular formation in vitro. Although all the PSAs inhibited VEGF production in KLN205 tumours in vivo and cells in vitro, in LLC tumours and cells only UFH and dalteparin inhibited VEGF production, whereas danaparoid did not. In both LLC and KLN205 tumours in vivo, heparanase activity was inhibited by UFH and dalteparin, but not by danaparoid. Hence, UFH and dalteparin may be more effective than danaparoid at inhibiting cancer progression in DIC patients with solid tumours, due at least in part to their ability to suppress VEGF and heparanase in tumours.

  12. Heparin-binding growth factor, pleiotrophin, mediates neuritogenic activity of embryonic pig brain-derived chondroitin sulfate/dermatan sulfate hybrid chains.

    PubMed

    Bao, Xingfeng; Mikami, Tadahisa; Yamada, Shuhei; Faissner, Andreas; Muramatsu, Takashi; Sugahara, Kazuyuki

    2005-03-11

    Chondroitin sulfate (CS) and dermatan sulfate (DS) chains play roles in the central nervous system. Most notably, CS/DS hybrid chains (E-CS/DS) purified from embryonic pig brains bind growth factors and promote neurite outgrowth toward embryonic mouse hippocampal neurons in culture. However, the neuritogenic mechanism is not well understood. Here we showed that pleiotrophin (PTN), a heparin-binding growth factor, produced mainly by glia cells, was the predominant binding partner for E-CS/DS in the membrane-associated protein fraction of neonatal rat brain. The CS/DS chains were separated on a PTN column into unbound, low affinity, and high affinity fractions. The latter two fractions promoted outgrowth of dendrite- and axon-like neurites, respectively, whereas the unbound fraction showed no such activity. The activity of the low affinity fraction was abolished by an anti-PTN antibody or when glia cells were removed from the culture. In contrast, the high affinity fraction displayed activity under both these conditions. Hence, PTN mainly from glia cells mediated the activity of the low affinity but not the high affinity fraction. The anti-CS antibody 473HD neutralized the neuritogenic activities of both fractions. Interaction analysis indicated that the 473HD epitope and PTN-binding domains in the E-CS/DS chains largely overlap. The three affinity subfractions differed in disaccharide composition and the distribution of l-iduronic acid-containing disaccharides along the chains. Oversulfated disaccharides and nonconsecutive iduronic acid-containing units were the requirements for the E-CS/DS chains to bind PTN and to exhibit the neuritogenic activities. Thus, CS subpopulations with distinct structures in the mammalian brain play different roles in neuritogenesis through distinct molecular mechanisms, at least in part by regulating the functions of growth factors.

  13. Fluence Rate Differences in Photodynamic Therapy Efficacy and Activation of Epidermal Growth Factor Receptor after Treatment of the Tumor-Involved Murine Thoracic Cavity

    PubMed Central

    Grossman, Craig E.; Carter, Shirron L.; Czupryna, Julie; Wang, Le; Putt, Mary E.; Busch, Theresa M.

    2016-01-01

    Photodynamic therapy (PDT) of the thoracic cavity can be performed in conjunction with surgery to treat cancers of the lung and its pleura. However, illumination of the cavity results in tissue exposure to a broad range of fluence rates. In a murine model of intrathoracic PDT, we studied the efficacy of 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH; Photochlor®)-mediated PDT in reducing the burden of non-small cell lung cancer for treatments performed at different incident fluence rates (75 versus 150 mW/cm). To better understand a role for growth factor signaling in disease progression after intrathoracic PDT, the expression and activation of epidermal growth factor receptor (EGFR) was evaluated in areas of post-treatment proliferation. The low fluence rate of 75 mW/cm produced the largest reductions in tumor burden. Bioluminescent imaging and histological staining for cell proliferation (anti-Ki-67) identified areas of disease progression at both fluence rates after PDT. However, increased EGFR activation in proliferative areas was detected only after treatment at the higher fluence rate of 150 mW/cm. These data suggest that fluence rate may affect the activation of survival factors, such as EGFR, and weaker activation at lower fluence rate could contribute to a smaller tumor burden after PDT at 75 mW/cm. PMID:26784170

  14. Urokinase-type Plasminogen Activator-like Proteases in Teleosts Lack Genuine Receptor-binding Epidermal Growth Factor-like Domains*

    PubMed Central

    Bager, René; Kristensen, Thomas K.; Jensen, Jan K.; Szczur, Agnieszka; Christensen, Anni; Andersen, Lisbeth M.; Johansen, Jesper S.; Larsen, Niels; Baatrup, Erik; Huang, Mingdong; Ploug, Michael; Andreasen, Peter A.

    2012-01-01

    Plasminogen activation catalyzed by urokinase-type plasminogen activator (uPA) plays an important role in normal and pathological tissue remodeling processes. Since its discovery in the mid-1980s, the cell membrane-anchored urokinase-type plasminogen activator receptor (uPAR) has been believed to be central to the functions of uPA, as uPA-catalyzed plasminogen activation activity appeared to be confined to cell surfaces through the binding of uPA to uPAR. However, a functional uPAR has so far only been identified in mammals. We have now cloned, recombinantly produced, and characterized two zebrafish proteases, zfuPA-a and zfuPA-b, which by several criteria are the fish orthologs of mammalian uPA. Thus, both proteases catalyze the activation of fish plasminogen efficiently and both proteases are inhibited rapidly by plasminogen activator inhibitor-1 (PAI-1). But zfuPA-a differs from mammalian uPA by lacking the exon encoding the uPAR-binding epidermal growth factor-like domain; zfuPA-b differs from mammalian uPA by lacking two cysteines of the epidermal growth factor-like domain and a uPAR-binding sequence comparable with that found in mammalian uPA. Accordingly, no zfuPA-b binding activity could be found in fish white blood cells or fish cell lines. We therefore propose that the current consensus of uPA-catalyzed plasminogen activation taking place on cell surfaces, derived from observations with mammals, is too narrow. Fish uPAs appear incapable of receptor binding in the manner known from mammals and uPA-catalyzed plasminogen activation in fish may occur mainly in solution. Studies with nonmammalian vertebrate species are needed to obtain a comprehensive understanding of the mechanism of plasminogen activation. PMID:22733817

  15. Selective inhibition of responses to nerve growth factor and of microtubule-associated protein phosphorylation by activators of adenylate cyclase.

    PubMed

    Greene, L A; Drexler, S A; Connolly, J L; Rukenstein, A; Green, S H

    1986-11-01

    To study the influence of cAMP on cellular responses to nerve growth factor (NGF) and to use elevation of intracellular cAMP to probe the NGF mechanism, cultured PC12 pheochromocytoma cells were exposed to forskolin and cholera toxin. As in other cell types, the latter agents greatly increased PC12 cell cAMP levels. Such treatment also brought about a reversible, dose-dependent suppression of NGF-promoted regeneration of neurites. In support of the role of cAMP in this effect, regeneration blockage by forskolin was potentiated by phosphodiesterase inhibitors. When tested on NGF-stimulated initiation of process outgrowth, cholera toxin and forskolin exerted a dual effect. As in previous studies, these drugs, when applied along with NGF, significantly enhanced the initial formation of short cytoplasmic extensions. However, after approximately 3 d of NGF exposure, at which time such extensions begin to acquire the morphological and ultrastructural features of neurites, these agents suppressed process outgrowth. That is, the neurites were fewer in number, significantly less branched, and much shorter than in control cultures. Such changes also occurred when these drugs were added to cultures that had been pretreated with NGF alone. Whereas forskolin and cholera toxin affect the formation and regeneration of neurites, these drugs did not interfere with the short-latency, transient changes in surface morphology that are triggered by NGF, nor did they inhibit transcription-dependent priming. In contrast, the rapidly occurring NGF-induced phosphorylation of tyrosine hydroxylase was suppressed. Moreover, forskolin and cholera toxin rapidly and selectively blocked the NGF-promoted phosphorylation of a set of microtubule-associated proteins known as chartins. Previous observations have suggested a causal relationship between NGF-induced chartin microtubule-associated protein phosphorylation and the formation and outgrowth of neurites. This is supported by the present data and

  16. Nerve growth factor promotes human hemopoietic colony growth and differentiation

    SciTech Connect

    Matsuda, H.; Coughlin, M.D.; Bienenstock, J.; Denburg, J.A. )

    1988-09-01

    Nerve growth factor (NGF) is a neurotropic polypeptide necessary for the survival and growth of some central neurons, as well as sensory afferent and sympathetic neurons. Much is now known of the structural and functional characteristics of NGF, whose gene has recently been clones. Since it is synthesized in largest amounts by the male mouse submandibular gland, its role exclusively in nerve growth is questionable. These experiments indicate that NGF causes a significant stimulation of granulocyte colonies grown from human peripheral blood in standard hemopoietic methylcellulose assays. Further, NGF appears to act in a relatively selective fashion to induce the differentiation of eosinophils and basophils/mast cells. Depletion experiments show that the NGF effect may be T-cell dependent and that NGF augments the colony-stimulating effect of supernatants from the leukemic T-cell (Mo) line. The hemopoietic activity of NGF is blocked by {sup 125}I-polyclonal and monoclonal antibodies to NGF. The authors conclude that NGF may indirectly act as a local growth factor in tissues other than those of the nervous system by causing T cells to synthesize or secrete molecules with colony-stimulating activity. In view of the synthesis of NGF in tissue injury, the involvement of basophils/mast cells and eosinophils in allergic and other inflammatory processes, and the association of mast cells with fibrosis and tissue repair, they postulate that NGF plays an important biological role in a variety of repair processes.

  17. Preparation and functional characterization of human vascular endothelial growth factor-melittin fusion protein with analysis of the antitumor activity in vitro and in vivo.

    PubMed

    Wang, Dingding; Hu, Lili; Su, Manman; Wang, Ju; Xu, Tianmin

    2015-09-01

    Vascular endothelial growth factor and its tyrosine kinase receptors have been identified as key mediators of the regulation of pathologic blood vessel growth and maintenance in the promotion of angiogenesis and tumor growth. Therefore, an alternative approach to destroying tumor endothelium would be to make this tissue particularly sensitive to VEGF-mediated drug delivery. To verify this hypothesis, we generated a protein containing VEGF165 fused to melittin. Melittin is a small linear peptide composed of 26 amino acid residues that can exert toxic or inhibitory effects on many types of tumor cells. This protein is a cytolytic peptide that attacks lipid membranes, leading to significant toxicity. In the present study, the Pichia pastoris expression system was used to express the fusion protein. Under optimal conditions, stable VEGF165-melittin production was achieved using a series of purification steps. The activity of VEGF165-melittin fusion protein was compared with melittin for its ability to suppress the growth of tumor cell line in vitro. The fusion toxin selectively inhibited growth of human hepatocellular carcinoma HepG-2 cell line with high expression of VEGFR-2. We found that sensitivity of VEGFR-2 transfected 293 cells to VEGF165-melittin enhanced as the cellular VEGFR-2 density increased. In an in vivo initial experiment, the fusion protein inhibited tumor growth in xenografts assays. Furthermore, successful expression and characterization of the fusion protein demonstrated its efficacy for use as a novel treatment strategy for cancer. PMID:26166416

  18. Preparation and functional characterization of human vascular endothelial growth factor-melittin fusion protein with analysis of the antitumor activity in vitro and in vivo.

    PubMed

    Wang, Dingding; Hu, Lili; Su, Manman; Wang, Ju; Xu, Tianmin

    2015-09-01

    Vascular endothelial growth factor and its tyrosine kinase receptors have been identified as key mediators of the regulation of pathologic blood vessel growth and maintenance in the promotion of angiogenesis and tumor growth. Therefore, an alternative approach to destroying tumor endothelium would be to make this tissue particularly sensitive to VEGF-mediated drug delivery. To verify this hypothesis, we generated a protein containing VEGF165 fused to melittin. Melittin is a small linear peptide composed of 26 amino acid residues that can exert toxic or inhibitory effects on many types of tumor cells. This protein is a cytolytic peptide that attacks lipid membranes, leading to significant toxicity. In the present study, the Pichia pastoris expression system was used to express the fusion protein. Under optimal conditions, stable VEGF165-melittin production was achieved using a series of purification steps. The activity of VEGF165-melittin fusion protein was compared with melittin for its ability to suppress the growth of tumor cell line in vitro. The fusion toxin selectively inhibited growth of human hepatocellular carcinoma HepG-2 cell line with high expression of VEGFR-2. We found that sensitivity of VEGFR-2 transfected 293 cells to VEGF165-melittin enhanced as the cellular VEGFR-2 density increased. In an in vivo initial experiment, the fusion protein inhibited tumor growth in xenografts assays. Furthermore, successful expression and characterization of the fusion protein demonstrated its efficacy for use as a novel treatment strategy for cancer.

  19. Thrombospondin-1 (TSP-1) Analogs ABT-510 and ABT-898 Inhibit Prolactinoma Growth and Recover Active Pituitary Transforming Growth Factor-β1 (TGF-β1)

    PubMed Central

    Recouvreux, M. Victoria; Camilletti, M. Andrea; Rifkin, Daniel B.; Becu-Villalobos, Damasia

    2012-01-01

    Prolactinomas are the most prevalent type of secreting pituitary tumors in humans and generally respond well to a medical therapy with dopamine agonists. However, for patients exhibiting resistance to dopaminergic drugs, alternative treatments are desired. Antiangiogenic strategies might represent a potential therapy for these tumors. Thrombospondin 1 (TSP-1) is a large multifunctional glycoprotein involved in multiple biological processes including angiogenesis, apoptosis, and activation of TGF-β1. Because tumors that overexpress TSP-1 grow more slowly, have fewer metastases, and have decreased angiogenesis, TSP-1 provides a novel target for cancer treatment. ABT-510 and ABT-898 are TSP-1 synthetic analogs that mimic its antiangiogenic action. In the present study, we explored the potential effect of ABT-510 and ABT-898 on experimental prolactinomas induced by chronic diethylstilbestrol (DES) treatment in female rats. We demonstrated that a 2-wk treatment with ABT-510 and ABT-898 counteracted the increase in pituitary size and serum prolactin levels as well as the pituitary proliferation rate induced by DES. These inhibitory effects on tumor growth could be mediated by the antiangiogenic properties of the drugs. We also demonstrated that ABT-510 and ABT-898, in addition to their described antiangiogenic effects, increased active TGF-β1 level in the tumors. We postulate that the recovery of the local cytokine activation participates in the inhibition of lactotrope function. These results place these synthetic TSP-1 analogs as potential alternative or complementary treatments in dopamine agonist-resistant prolactinomas. PMID:22700773

  20. The Enzymatic Activity of Apoptosis-inducing Factor Supports Energy Metabolism Benefiting the Growth and Invasiveness of Advanced Prostate Cancer Cells*

    PubMed Central

    Lewis, Eric M.; Wilkinson, Amanda S.; Jackson, Jacqueline S.; Mehra, Rohit; Varambally, Sooryanarayana; Chinnaiyan, Arul M.; Wilkinson, John C.

    2012-01-01

    Apoptosis-inducing factor (AIF) promotes cell death yet also controls mitochondrial homeostasis and energy metabolism. It is unclear how these activities are coordinated, and the impact of AIF upon human disease, in particular cancer, is not well documented. In this study we have explored the contribution of AIF to the progression of prostate cancer. Analysis of archival gene expression data demonstrated that AIF transcript levels are elevated in human prostate cancer, and we found that AIF protein is increased in prostate tumors. Suppression of AIF expression in the prostate cancer cell lines LNCaP, DU145, and PC3 demonstrated that AIF does not contribute to cell toxicity via a variety of chemical death triggers, and growth under nutrient-rich conditions is largely unaffected by AIF ablation. However, under growth stress conditions, AIF depletion from DU145 and PC3 cell lines led to significant reductions in cell survival and growth that were not observed in LNCaP cells. Moreover AIF-deficient PC3 cells exhibited substantial reduction of tumorigenic growth in vivo. This reduced survival correlated with decreased expression of mitochondrial complex I protein subunits and concomitant changes in glucose metabolism. Finally, restoration of AIF-deficient PC3 cells with AIF variants demonstrated that the enzymatic activity of AIF is required for aggressive growth. Overall these studies show that AIF is an important factor for advanced prostate cancer cells and that through control of energy metabolism and redox balance, the enzymatic activity of AIF is critical for this support. PMID:23118229

  1. Hypoxia-induced cell death and changes in hypoxia-inducible factor-1 activity in PC12 cells upon exposure to nerve growth factor.

    PubMed

    Charlier, Nico; Leclere, Norbert; Felderhoff, Ursula; Heldt, Julia; Kietzmann, Thomas; Obladen, Michael; Gross, Johann

    2002-07-15

    The transcription factor hypoxia-inducible factor-1 (HIF-1) strongly contributes to the expression of adaptive genes under hypoxic conditions. In addition, HIF-1 has been implicated in the regulation of delayed neuronal cell death. Suspension-grown and adherent PC12 cells treated with NGF were used as an experimental model for studying the relationship between hypoxia-induced cell death and activation of HIF-1. Cell damage was assessed by flow cytometry of double-stained (Annexin V and propidiumiodide) cells, and by analysis of the overall death parameters LDH and mitochondrial dehydrogenase. In parallel, cells were transfected with a control and a three-hypoxia-responsive-elements (HRE)-containing vector and HIF-1-driven luciferase activity was determined. Exposure of NGF-treated PC12 cells to hypoxia resulted in a higher cell death rate when compared to untreated controls. PC12 cells exposed for 2 days to NGF exhibited a decrease of HIF-1 activity up to a factor of ten. This decrease may contribute to the enhanced hypoxia-induced cell death via reduced expression of HIF-1alpha-regulated genes responsible for adaptation to hypoxia, like those for glucose transport proteins and enzymes of the glycolytic chain. The decrease in HIF-1 activity and the increase in hypoxia sensitivity may suggest that NGF act as an hierarchically organized signaling molecule.

  2. Peroxisome proliferator-activated receptor γ regulates genes involved in insulin/insulin-like growth factor signaling and lipid metabolism during adipogenesis through functionally distinct enhancer classes.

    PubMed

    Oger, Frédérik; Dubois-Chevalier, Julie; Gheeraert, Céline; Avner, Stéphane; Durand, Emmanuelle; Froguel, Philippe; Salbert, Gilles; Staels, Bart; Lefebvre, Philippe; Eeckhoute, Jérôme

    2014-01-10

    The nuclear receptor peroxisome proliferator-activated receptor (PPAR) is a transcription factor whose expression is induced during adipogenesis and that is required for the acquisition and control of mature adipocyte functions. Indeed, PPAR induces the expression of genes involved in lipid synthesis and storage through enhancers activated during adipocyte differentiation. Here, we show that PPAR also binds to enhancers already active in preadipocytes as evidenced by an active chromatin state including lower DNA methylation levels despite higher CpG content. These constitutive enhancers are linked to genes involved in the insulin/insulin-like growth factor signaling pathway that are transcriptionally induced during adipogenesis but to a lower extent than lipid metabolism genes, because of stronger basal expression levels in preadipocytes. This is consistent with the sequential involvement of hormonal sensitivity and lipid handling during adipocyte maturation and correlates with the chromatin structure dynamics at constitutive and activated enhancers. Interestingly, constitutive enhancers are evolutionary conserved and can be activated in other tissues, in contrast to enhancers controlling lipid handling genes whose activation is more restricted to adipocytes. Thus, PPAR utilizes both broadly active and cell type-specific enhancers to modulate the dynamic range of activation of genes involved in the adipogenic process.

  3. Peroxisome Proliferator-activated Receptor γ Regulates Genes Involved in Insulin/Insulin-like Growth Factor Signaling and Lipid Metabolism during Adipogenesis through Functionally Distinct Enhancer Classes*

    PubMed Central

    Oger, Frédérik; Dubois-Chevalier, Julie; Gheeraert, Céline; Avner, Stéphane; Durand, Emmanuelle; Froguel, Philippe; Salbert, Gilles; Staels, Bart; Lefebvre, Philippe; Eeckhoute, Jérôme

    2014-01-01

    The nuclear receptor peroxisome proliferator-activated receptor (PPAR) γ is a transcription factor whose expression is induced during adipogenesis and that is required for the acquisition and control of mature adipocyte functions. Indeed, PPARγ induces the expression of genes involved in lipid synthesis and storage through enhancers activated during adipocyte differentiation. Here, we show that PPARγ also binds to enhancers already active in preadipocytes as evidenced by an active chromatin state including lower DNA methylation levels despite higher CpG content. These constitutive enhancers are linked to genes involved in the insulin/insulin-like growth factor signaling pathway that are transcriptionally induced during adipogenesis but to a lower extent than lipid metabolism genes, because of stronger basal expression levels in preadipocytes. This is consistent with the sequential involvement of hormonal sensitivity and lipid handling during adipocyte maturation and correlates with the chromatin structure dynamics at constitutive and activated enhancers. Interestingly, constitutive enhancers are evolutionary conserved and can be activated in other tissues, in contrast to enhancers controlling lipid handling genes whose activation is more restricted to adipocytes. Thus, PPARγ utilizes both broadly active and cell type-specific enhancers to modulate the dynamic range of activation of genes involved in the adipogenic process. PMID:24288131

  4. Placental-Specific sFLT-1 e15a Protein Is Increased in Preeclampsia, Antagonizes Vascular Endothelial Growth Factor Signaling, and Has Antiangiogenic Activity.

    PubMed

    Palmer, Kirsten R; Kaitu'u-Lino, Tu'uhevaha J; Hastie, Roxanne; Hannan, Natalie J; Ye, Louie; Binder, Natalie; Cannon, Ping; Tuohey, Laura; Johns, Terrance G; Shub, Alexis; Tong, Stephen

    2015-12-01

    In preeclampsia, the antiangiogenic factor soluble fms-like tyrosine kinase-1 (sFLT-1) is released from placenta into the maternal circulation, causing endothelial dysfunction and organ injury. A recently described splice variant, sFLT-1 e15a, is primate specific and the most abundant placentally derived sFLT-1. Therefore, it may be the major sFLT-1 isoform contributing to the pathophysiology of preeclampsia. sFLT-1 e15a protein remains poorly characterized: its bioactivity has not been comprehensively examined, and serum levels in normal and preeclamptic pregnancy have not been reported. We generated and validated an sFLT-1 e15a-specific ELISA to further characterize serum levels during pregnancy, and in the presence of preeclampsia. Furthermore, we performed assays to examine the bioactivity and antiangiogenic properties of sFLT-1 e15a protein. sFLT-1 e15a was expressed in the syncytiotrophoblast, and serum levels rose across pregnancy. Strikingly, serum levels were increased 10-fold in preterm preeclampsia compared with normotensive controls. We confirmed sFLT-1 e15a is bioactive and is able to inhibit vascular endothelial growth factor signaling of vascular endothelial growth factor receptor 2 and block downstream Akt phosphorylation. Furthermore, sFLT-1 e15a has antiangiogenic properties. sFLT-1 e15a decreased endothelial cell migration, invasion, and inhibited endothelial cell tube formation. Administering sFLT-1 e15a blocked vascular endothelial growth factor induced sprouts from mouse aortic rings ex vivo. We have demonstrated that sFLT-1 e15a is increased in preeclampsia, antagonizes vascular endothelial growth factor signaling, and has antiangiogenic activity. Future development of diagnostics and therapeutics for preeclampsia should consider targeting placentally derived sFLT-1 e15a.

  5. Growth factor-induced activation of a kinase activity which causes regulatory phosphorylation of p42/microtubule-associated protein kinase.

    PubMed Central

    L'Allemain, G; Her, J H; Wu, J; Sturgill, T W; Weber, M J

    1992-01-01

    p42/microtubule-associated protein kinase (p42mapk) is activated by tyrosine and threonine phosphorylation, and its regulatory phosphorylation is likely to be important in signalling pathways involved in growth control, secretion, and differentiation. Here we show that treatment of quiescent 3T3 cells with diverse agonists results in the appearance of an activity capable of causing the in vitro phosphorylation of p42mapk on the regulatory tyrosine and to a lesser extent on the regulatory threonine, resulting in enzymatic activation of the p42mapk. This p42mapk-activating activity is capable of phosphorylating a kinase-defective p42mapk mutant, thus confirming its activity as a kinase. Images PMID:1314951

  6. Wingless-type family member 3A triggers neuronal polarization via cross-activation of the insulin-like growth factor-1 receptor pathway

    PubMed Central

    Bernis, María E.; Oksdath, Mariana; Dupraz, Sebastián; Nieto Guil, Alvaro; Fernández, Marisa M.; Malchiodi, Emilio L.; Rosso, Silvana B.; Quiroga, Santiago

    2013-01-01

    Initial axonal elongation is essential for neuronal polarization and requires polarized activation of IGF-1 receptors (IGF-1r) and the phosphatidylinositol 3 kinase (PI3k) pathway. Wingless-type family growth factors (Wnts) have also been implied in the regulation of axonal development. It is not known, however, if Wnts have any participation in the regulation of initial axonal outgrowth and the establishment of neuronal polarity. We used cultured hippocampal neurons and growth cone particles (GCPs) isolated from fetal rat brain to show that stimulation with the wingless family factor 3A (Wnt3a) was sufficient to promote neuronal polarization in the absence of IGF-1 or high insulin. We also show that Wnt3a triggered a strong activation of IGF-1r, PI3k, and Akt in developmental Stage 2 neurons and that the presence of activatable IGF-1r and PI3k activation were necessary for Wnt3a polarizing effects. Surface plasmon resonance (SPR) experiments show that Wnt3a did not bind specifically to the IGF-1r. Using crosslinking and immuno-precipitation experiments, we show that stimulation with Wnt3a triggered the formation of a complex including IGF-1r-Wnt3a-Frizzled-7. We conclude that Wnt3a triggers polarization of neurons via cross-activation of the IGF-1r/PI3k pathway upon binding to Fz7. PMID:24298236

  7. Disconnecting the Yin and Yang Relation of Epidermal Growth Factor Receptor (EGFR)-Mediated Delivery: A Fully Synthetic, EGFR-Targeted Gene Transfer System Avoiding Receptor Activation

    PubMed Central

    Schäfer, A.; Pahnke, A.; Schaffert, D.; van Weerden, W.M.; de Ridder, C.M.A.; Rödl, W.; Vetter, A.; Spitzweg, C.; Kraaij, R.; Wagner, E.

    2011-01-01

    Abstract The epidermal growth factor receptor (EGFR) is upregulated within a high percentage of solid tumors and hence is an attractive target for tumor-targeted therapies including gene therapy. The natural EGFR ligand epidermal growth factor (EGF) has been used for this purpose, despite the risk of mitogenic effects due to EGFR activation. We have developed a fully synthetic, EGFR-targeted gene delivery system based on PEGylated linear polyethylenimine (LPEI), allowing evaluation of different EGFR-binding peptides in terms of transfection efficiency and EGFR activation. Peptide sequences directly derived from the human EGF molecule enhanced transfection efficiency with concomitant EGFR activation. Only the EGFR-binding peptide GE11, which has been identified by phage display technique, showed specific enhancement of transfection on EGFR-overexpressing tumor cells including glioblastoma and hepatoma, but without EGFR activation. EGFR targeting led to high levels of cell association of fluorescently labeled polyplexes after only 30 min of incubation. EGF pretreatment of cells induced enhanced cellular internalization of all polyplex types tested, pointing at generally enhanced macropinocytosis. EGF polyplexes diminished cell surface expression of EGFR for up to 4 hr, whereas GE11 polyplexes did not. In a clinically relevant orthotopic prostate cancer model, intratumorally injected GE11 polyplexes were superior in inducing transgene expression when compared with untargeted polyplexes. PMID:21644815

  8. ERas protein is overexpressed and binds to the activated platelet-derived growth factor β receptor in bovine urothelial tumour cells associated with papillomavirus infection.

    PubMed

    Russo, Valeria; Roperto, Franco; Esposito, Iolanda; Ceccarelli, Dora Maria; Zizzo, Nicola; Leonardi, Leonardo; Capparelli, Rosanna; Borzacchiello, Giuseppe; Roperto, Sante

    2016-06-01

    Embryonic stem cell-expressed Ras (ERas) encodes a constitutively active form of guanosine triphosphatase (GTPase) that binds to and activates phosphatidylinositol 3 kinase (PI3K), which in turn phosphorylates and activates downstream targets such as Akt. The current study evaluated ERas regulation and expression in papillomavirus-associated urothelial tumours in cattle grazing on lands rich in bracken fern. ERas was found upregulated and overexpressed by PCR, real time PCR and Western blot. Furthermore, protein overexpression was also confirmed by immunohistochemistry. ERas was found to interact physically and colocalise with the activated platelet derived growth factor β receptor (PDGFβR) by coimmunoprecipitation and laser scanning confocal investigations. Phosphorylation of Akt, a downstream effector both of ERas and PDGFβR, appeared to be increased in urothelial tumour cells. Altogether, these data indicate that ERas/PDGFβR complex could play a role in the pathogenesis of bovine papillomavirus-associated bladder neoplasia. PMID:27256024

  9. Active G protein-coupled receptors (GPCR), matrix metalloproteinases 2/9 (MMP2/9), heparin-binding epidermal growth factor (hbEGF), epidermal growth factor receptor (EGFR), erbB2, and insulin-like growth factor 1 receptor (IGF-1R) are necessary for trenbolone acetate-induced alterations in protein turnover rate of fused bovine satellite cell cultures.

    PubMed

    Thornton, K J; Kamanga-Sollo, E; White, M E; Dayton, W R

    2016-06-01

    Trenbolone acetate (TBA), a testosterone analog, increases protein synthesis and decreases protein degradation in fused bovine satellite cell (BSC) cultures. However, the mechanism through which TBA alters these processes remains unknown. Recent studies indicate that androgens improve rate and extent of muscle growth through a nongenomic mechanism involving G protein-coupled receptors (GPCR), matrix metalloproteinases (MMP), heparin-binding epidermal growth factor (hbEGF), the epidermal growth factor receptor (EGFR), erbB2, and the insulin-like growth factor-1 receptor (IGF-1R). We hypothesized that TBA activates GPCR, resulting in activation of MMP2/9 that releases hbEGF, which activates the EGFR and/or erbB2. To determine whether the proposed nongenomic pathway is involved in TBA-mediated alterations in protein turnover, fused BSC cultures were treated with TBA in the presence or absence of inhibitors for GPCR, MMP2/9, hbEGF, EGFR, erbB2, or IGF-1R, and resultant protein synthesis and degradation rates were analyzed. Assays were replicated at least 9 times for each inhibitor experiment utilizing BSC cultures obtained from at least 3 different steers that had no previous exposure to steroid compounds. As expected, fused BSC cultures treated with 10 n TBA exhibited increased ( < 0.05) protein synthesis rates and decreased ( < 0.05) protein degradation rates when compared to control cultures. Treatment of fused BSC cultures with 10 n TBA in the presence of inhibitors for GPCR, MMP2/9, hbEGF, EGFR, erbB2, or IGF-1R suppressed ( < 0.05) TBA-mediated increases in protein synthesis rate. Alternatively, inhibition of GPCR, MMP2/9, hbEGF, EGFR, erbB2, or IGF-1R in the presence of 10 n TBA each had no ( > 0.05) effect on TBA-mediated decreases in protein degradation. However, inhibition of both EGFR and erbB2 in the presence of 10 n TBA resulted in decreased ( < 0.05) ability of TBA to decrease protein degradation rate. Additionally, fused BSC cultures treated with 10 n

  10. Active G protein-coupled receptors (GPCR), matrix metalloproteinases 2/9 (MMP2/9), heparin-binding epidermal growth factor (hbEGF), epidermal growth factor receptor (EGFR), erbB2, and insulin-like growth factor 1 receptor (IGF-1R) are necessary for trenbolone acetate-induced alterations in protein turnover rate of fused bovine satellite cell cultures.

    PubMed

    Thornton, K J; Kamanga-Sollo, E; White, M E; Dayton, W R

    2016-06-01

    Trenbolone acetate (TBA), a testosterone analog, increases protein synthesis and decreases protein degradation in fused bovine satellite cell (BSC) cultures. However, the mechanism through which TBA alters these processes remains unknown. Recent studies indicate that androgens improve rate and extent of muscle growth through a nongenomic mechanism involving G protein-coupled receptors (GPCR), matrix metalloproteinases (MMP), heparin-binding epidermal growth factor (hbEGF), the epidermal growth factor receptor (EGFR), erbB2, and the insulin-like growth factor-1 receptor (IGF-1R). We hypothesized that TBA activates GPCR, resulting in activation of MMP2/9 that releases hbEGF, which activates the EGFR and/or erbB2. To determine whether the proposed nongenomic pathway is involved in TBA-mediated alterations in protein turnover, fused BSC cultures were treated with TBA in the presence or absence of inhibitors for GPCR, MMP2/9, hbEGF, EGFR, erbB2, or IGF-1R, and resultant protein synthesis and degradation rates were analyzed. Assays were replicated at least 9 times for each inhibitor experiment utilizing BSC cultures obtained from at least 3 different steers that had no previous exposure to steroid compounds. As expected, fused BSC cultures treated with 10 n TBA exhibited increased ( < 0.05) protein synthesis rates and decreased ( < 0.05) protein degradation rates when compared to control cultures. Treatment of fused BSC cultures with 10 n TBA in the presence of inhibitors for GPCR, MMP2/9, hbEGF, EGFR, erbB2, or IGF-1R suppressed ( < 0.05) TBA-mediated increases in protein synthesis rate. Alternatively, inhibition of GPCR, MMP2/9, hbEGF, EGFR, erbB2, or IGF-1R in the presence of 10 n TBA each had no ( > 0.05) effect on TBA-mediated decreases in protein degradation. However, inhibition of both EGFR and erbB2 in the presence of 10 n TBA resulted in decreased ( < 0.05) ability of TBA to decrease protein degradation rate. Additionally, fused BSC cultures treated with 10 n

  11. Anti-cancer activity of an osthole derivative, NBM-T-BMX-OS01: targeting vascular endothelial growth factor receptor signaling and angiogenesis.

    PubMed

    Yang, Hung-Yu; Hsu, Ya-Fen; Chiu, Pei-Ting; Ho, Shiau-Jing; Wang, Chi-Han; Chi, Chih-Chin; Huang, Yu-Han; Lee, Cheng-Feng; Li, Ying-Shiuan; Ou, George; Hsu, Ming-Jen

    2013-01-01

    Angiogenesis occurs during tissue growth, development and wound healing. It is also required for tumor progression and represents a rational target for therapeutic intervention. NBM-T-BMX-OS01 (BMX), derived from the semisynthesis of osthole, an active ingredient isolated from Chinese herb Cnidium monnieri (L.) Cuss., was recently shown to enhance learning and memory in rats. In this study, we characterized the anti-angiogenic activities of NBM-T-BMX-OS01 (BMX) in an effort to develop novel inhibitors to suppress angiogenesis and tumor growth. BMX inhibited vascular endothelial growth factor (VEGF)-induced proliferation, migration and endothelial tube formation in human umbilical endothelial cells (HUVECs). BMX also attenuated VEGF-induced microvessel sprouting from aortic rings ex vivo and reduced HCT116 colorectal cancer cells-induced angiogenesis in vivo. Moreover, BMX inhibited the phosphorylation of VEGFR2, FAK, Akt and ERK in HUVECs exposed to VEGF. BMX was also shown to inhibit HCT116 cell proliferation and to suppress the growth of subcutaneous xenografts of HCT116 cells in vivo. Taken together, this study provides evidence that BMX modulates vascular endothelial cell remodeling and leads to the inhibition of tumor angiogenesis. These results also support the role of BMX as a potential drug candidate and warrant the clinical development in the treatment of cancer. PMID:24312323

  12. Nerve growth factor (NGF) regulates activity of nuclear factor of activated T-cells (NFAT) in neurons via the phosphatidylinositol 3-kinase (PI3K)-Akt-glycogen synthase kinase 3β (GSK3β) pathway.

    PubMed

    Kim, Man-Su; Shutov, Leonid P; Gnanasekaran, Aswini; Lin, Zhihong; Rysted, Jacob E; Ulrich, Jason D; Usachev, Yuriy M

    2014-11-01

    The Ca(2+)/calcineurin-dependent transcription factor nuclear factor of activated T-cells (NFAT) plays an important role in regulating many neuronal functions, including excitability, axonal growth, synaptogenesis, and neuronal survival. NFAT can be activated by action potential firing or depolarization that leads to Ca(2+)/calcineurin-dependent dephosphorylation of NFAT and its translocation to the nucleus. Recent data suggest that NFAT and NFAT-dependent functions in neurons can also be potently regulated by NGF and other neurotrophins. However, the mechanisms of NFAT regulation by neurotrophins are not well understood. Here, we show that in dorsal root ganglion sensory neurons, NGF markedly facilitates NFAT-mediated gene expression induced by mild depolarization. The effects of NGF were not associated with changes in [Ca(2+)]i and were independent of phospholipase C activity. Instead, the facilitatory effect of NGF depended on activation of the PI3K/Akt pathway downstream of the TrkA receptor and on inhibition of glycogen synthase kinase 3β (GSK3β), a protein kinase known to phosphorylate NFAT and promote its nuclear export. Knockdown or knockout of NFATc3 eliminated this facilitatory effect. Simultaneous monitoring of EGFP-NFATc3 nuclear translocation and [Ca(2+)]i changes in dorsal root ganglion neurons indicated that NGF slowed the rate of NFATc3 nuclear export but did not affect its nuclear import rate. Collectively, our data suggest that NGF facilitates depolarization-induced NFAT activation by stimulating PI3K/Akt signaling, inactivating GSK3β, and thereby slowing NFATc3 export from the nucleus. We propose that NFAT serves as an integrator of neurotrophin action and depolarization-driven calcium signaling to regulate neuronal gene expression.

  13. Newly synthesized proteoglycans secreted by sequentially derived populations of cells from new-born rat calvaria: effects of transforming growth factor-beta and matrigenin activity.

    PubMed

    Chopra, R K; Li, Z M; Vickery, S; Anastassiades, T

    1990-10-01

    Three populations (1, 3 and 6) of bone cells, derived from rat calvaria by sequential enzymatic digestion, were cultured with [3H]glucosamine and [35S]sulfate, in the presence or absence of transforming growth factor-beta (TGF-beta) or bone-derived matrigenin activity. Population 6 synthesized a chondroitin sulfate proteoglycan (PG) and responded to the addition of the factors by increased rates of synthesis of hyaluronic acid (HA) and PG and an increase in the size of the HA. Comparisons of populations 1, 3 and 6 showed an ordered, spontaneous increase in HA and PG synthesis. However, the addition of matrigenin activity resulted in a much greater stimulation of PG, but not HA, synthesis in population 1 compared to population 6, suggesting a cellular organization in the calvarium whose net effect would be to direct PG synthesis towards the periphery of the tissue.

  14. Recombinant human nerve growth factor is biologically active and labels novel high-affinity binding sites in rat brain

    SciTech Connect

    Altar, C.A.; Burton, L.E.; Bennett, G.L.; Dugich-Djordjevic, M. )

    1991-01-01

    Iodinated recombinant human nerve growth factor (125I-rhNGF) stimulated neurite formation in PC12 cell cultures with a half-maximal potency of 35-49 pg/ml, compared with 39-52 pg/ml for rhNGF. In quantitative ligand autoradiography, the in vitro equilibrium binding of 125I-rhNGF to brain sections showed a 10-fold regional variation in density and was saturable, reversible, and specifically displaced by up to 74% with rhNGF or murine NGF (muNGF). At equilibrium, 125I-rhNGF bound to these sites with high affinity and low capacity (Bmax less than or equal to 13.2 fmol/mg of protein). Calculation of 125I-rhNGF binding affinity by kinetic methods gave average Kd values of 24 and 31 pM. Computer-generated maps revealed binding in brain regions not identified previously with 125I-muNGF, including hippocampus; dentate gyrus; amygdala; paraventricular thalamus; frontal, parietal, occipital, and cingulate cortices; nucleus accumbens; olfactory tubercle; subiculum; pineal gland; and medial geniculate nucleus. NGF binding sites were distributed in a 2-fold increasing medial-lateral gradient in the caudate-putamen and a 2-fold lateral-medial gradient in the nucleus accumbens. 125I-rhNGF binding sites were also found in most areas labeled by 125I-muNGF, including the interpedunucular nucleus, cerebellum, forebrain cholinergic nuclei, caudoventral caudate-putamen, and trigeminal nerve nucleus. 125I-rhNGF binding sites were absent from areas replete with low-affinity NGF binding sites, including circumventricular organs, myelinated fiber bundles, and choroid plexus. The present analysis provides an anatomical differentiation of high-affinity 125I-rhNGF binding sites and greatly expands the number of brain structures that may respond to endogenous NGF or exogenously administered rhNGF.

  15. [Stem cells and growth factors in wound healing].

    PubMed

    Pikuła, Michał; Langa, Paulina; Kosikowska, Paulina; Trzonkowski, Piotr

    2015-01-02

    Wound healing is a complex process which depends on the presence of various types of cells, growth factors, cytokines and the elements of extracellular matrix. A wound is a portal of entry for numerous pathogens, therefore during the evolution wound healing process has formed very early, being critical for the survival of every individual. Stem cells, which give rise to their early descendants progenitor cells and subsequently differentiated cells, play a specific role in the process of wound healing. Among the most important cells which take part in wound healing the following cells need to be distinguished: epidermal stem cells, dermal precursor of fibroblasts, adipose-derived stem cells as well as bone marrow cells. The activity of these cells is strictly regulated by various growth factors, inter alia epidermal growth factor (EGF), fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), transforming growth factor (TGF), vascular endothelial growth factor (VEGF). Any disorders in functioning of stem cells and biological activity of growth factors may lead to the defects in wound healing, for instance delayed wound healing or creation of hypertrophic scars. Therefore, knowledge concerning the mechanisms of wound healing is extremely essential from clinical point of view. In this review the current state of the knowledge of the role of stem cells and growth factors in the process of wound healing has been presented. Moreover, some clinical aspects of wound healing as well as the possibility of the therapy based on stem cells and growth factors have included.

  16. Cumulin, an Oocyte-secreted Heterodimer of the Transforming Growth Factor-β Family, Is a Potent Activator of Granulosa Cells and Improves Oocyte Quality.

    PubMed

    Mottershead, David G; Sugimura, Satoshi; Al-Musawi, Sara L; Li, Jing-Jie; Richani, Dulama; White, Melissa A; Martin, Georgia A; Trotta, Andrew P; Ritter, Lesley J; Shi, Junyan; Mueller, Thomas D; Harrison, Craig A; Gilchrist, Robert B

    2015-09-25

    Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are oocyte-specific growth factors with central roles in mammalian reproduction, regulating species-specific fecundity, ovarian follicular somatic cell differentiation, and oocyte quality. In the human, GDF9 is produced in a latent form, the mechanism of activation being an open question. Here, we produced a range of recombinant GDF9 and BMP15 variants, examined their in silico and physical interactions and their effects on ovarian granulosa cells (GC) and oocytes. We found that the potent synergistic actions of GDF9 and BMP15 on GC can be attributed to the formation of a heterodimer, which we have termed cumulin. Structural modeling of cumulin revealed a dimerization interface identical to homodimeric GDF9 and BMP15, indicating likely formation of a stable complex. This was confirmed by generation of recombinant heterodimeric complexes of pro/mature domains (pro-cumulin) and covalent mature domains (cumulin). Both pro-cumulin and cumulin exhibited highly potent bioactivity on GC, activating both SMAD2/3 and SMAD1/5/8 signaling pathways and promoting proliferation and expression of a set of genes associated with oocyte-regulated GC differentiation. Cumulin was more potent than pro-cumulin, pro-GDF9, pro-BMP15, or the two combined on GC. However, on cumulus-oocyte complexes, pro-cumulin was more effective than all other growth factors at notably improving oocyte quality as assessed by subsequent day 7 embryo development. Our results support a model of activation for human GDF9 dependent on cumulin formation through heterodimerization with BMP15. Oocyte-secreted cumulin is likely to be a central regulator of fertility in mono-ovular mammals.

  17. Cumulin, an Oocyte-secreted Heterodimer of the Transforming Growth Factor-β Family, Is a Potent Activator of Granulosa Cells and Improves Oocyte Quality*

    PubMed Central

    Mottershead, David G.; Sugimura, Satoshi; Al-Musawi, Sara L.; Li, Jing-Jie; Richani, Dulama; White, Melissa A.; Martin, Georgia A.; Trotta, Andrew P.; Ritter, Lesley J.; Shi, Junyan; Mueller, Thomas D.; Harrison, Craig A.; Gilchrist, Robert B.

    2015-01-01

    Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are oocyte-specific growth factors with central roles in mammalian reproduction, regulating species-specific fecundity, ovarian follicular somatic cell differentiation, and oocyte quality. In the human, GDF9 is produced in a latent form, the mechanism of activation being an open question. Here, we produced a range of recombinant GDF9 and BMP15 variants, examined their in silico and physical interactions and their effects on ovarian granulosa cells (GC) and oocytes. We found that the potent synergistic actions of GDF9 and BMP15 on GC can be attributed to the formation of a heterodimer, which we have termed cumulin. Structural modeling of cumulin revealed a dimerization interface identical to homodimeric GDF9 and BMP15, indicating likely formation of a stable complex. This was confirmed by generation of recombinant heterodimeric complexes of pro/mature domains (pro-cumulin) and covalent mature domains (cumulin). Both pro-cumulin and cumulin exhibited highly potent bioactivity on GC, activating both SMAD2/3 and SMAD1/5/8 signaling pathways and promoting proliferation and expression of a set of genes associated with oocyte-regulated GC differentiation. Cumulin was more potent than pro-cumulin, pro-GDF9, pro-BMP15, or the two combined on GC. However, on cumulus-oocyte complexes, pro-cumulin was more effective than all other growth factors at notably improving oocyte quality as assessed by subsequent day 7 embryo development. Our results support a model of activation for human GDF9 dependent on cumulin formation through heterodimerization with BMP15. Oocyte-secreted cumulin is likely to be a central regulator of fertility in mono-ovular mammals. PMID:26254468

  18. Inhibition of mitogen-activated protein kinase kinase, DNA methyltransferase, and transforming growth factor-β promotes differentiation of human induced pluripotent stem cells into enterocytes.

    PubMed

    Kodama, Nao; Iwao, Takahiro; Kabeya, Tomoki; Horikawa, Takashi; Niwa, Takuro; Kondo, Yuki; Nakamura, Katsunori; Matsunaga, Tamihide

    2016-06-01

    We previously reported that small-molecule compounds were effective in generating pharmacokinetically functional enterocytes from human induced pluripotent stem (iPS) cells. In this study, to determine whether the compounds promote the differentiation of human iPS cells into enterocytes, we investigated the effects of a combination of mitogen-activated protein kinase kinase (MEK), DNA methyltransferase (DNMT), and transforming growth factor (TGF)-β inhibitors on intestinal differentiation. Human iPS cells cultured on feeder cells were differentiated into endodermal cells by activin A. These endodermal-like cells were then differentiated into intestinal stem cells by fibroblast growth factor 2. Finally, the cells were differentiated into enterocyte cells by epidermal growth factor and small-molecule compounds. After differentiation, mRNA expression levels and drug-metabolizing enzyme activities were measured. The mRNA expression levels of the enterocyte marker sucrase-isomaltase and the major drug-metabolizing enzyme cytochrome P450 (CYP) 3A4 were increased by a combination of MEK, DNMT, and TGF-β inhibitors. The mRNA expression of CYP3A4 was markedly induced by 1α,25-dihydroxyvitamin D3. Metabolic activities of CYP1A1/2, CYP2B6, CYP2C9, CYP2C19, CYP3A4/5, UDP-glucuronosyltransferase, and sulfotransferase were also observed in the differentiated cells. In conclusion, MEK, DNMT, and TGF-β inhibitors can be used to promote the differentiation of human iPS cells into pharmacokinetically functional enterocytes.

  19. Activation of adenosine A2A receptors by polydeoxyribonucleotide increases vascular endothelial growth factor and protects against testicular damage induced by experimental varicocele in rats.

    PubMed

    Minutoli, Letteria; Arena, Salvatore; Bonvissuto, Giulio; Bitto, Alessandra; Polito, Francesca; Irrera, Natasha; Arena, Francesco; Fragalà, Eugenia; Romeo, Carmelo; Nicotina, Piero Antonio; Fazzari, Carmine; Marini, Herbert; Implatini, Alessandra; Grimaldi, Silvia; Cantone, Noemi; Di Benedetto, Vincenzo; Squadrito, Francesco; Altavilla, Domenica; Morgia, Giuseppe

    2011-03-15

    In rat experimental varicocele, polydeoxyribonucleotide (PDRN) induces vascular endothelial growth factor (VEGF) production, thereby enhancing testicular function. This may point to a new therapeutic approach in human varicocele.

  20. Rapid evaluation of tyrosine kinase activity of membrane-integrated human epidermal growth factor receptor using the yeast Gγ recruitment system.

    PubMed

    Fukuda, Nobuo; Honda, Shinya

    2015-04-17

    Epidermal growth factor receptor (EGFR) is a member of the receptor tyrosine kinase family and plays key roles in the regulation of fundamental cellular processes, including cell proliferation, migration, differentiation, and survival. Deregulation of EGFR tyrosine kinase activity is involved in the development and progression of human cancers. In the present study, we attempted to develop a method to evaluate the tyrosine kinase activity of human EGFR using the yeast Gγ recruitment system. Autophosphorylation of tyrosine residues on the cytoplasmic tail of EGFR induces recruitment of Grb2-fused Gγ subunits to the inner leaflet of the plasma membrane in yeast cells, which leads to G-protein signal transduction and activation of downstream signaling events, including mating and diploid cell growth. We demonstrate that our system is applicable for the evaluation of tyrosine kinase inhibitors, which are regarded as promising drug candidates to prevent the growth of tumor cells. This approach provides a rapid and easy-to-use tool to select EGFR-targeting tyrosine kinase inhibitors that are able to permeate eukaryotic membranes and function in intracellular environments.

  1. Epidermal growth factor receptor signaling in tissue

    SciTech Connect

    Shvartsman, Stanislav; Wiley, H. S.; Lauffenburger, Douglas A.

    2004-08-01

    Abstract: A peptide purified from the salivary gland of a mouse was shown few years ago to accelerate incisor eruption and eyelid opening in newborn mice, and was named epidermal growth factor (EGF). The members of this family of peptide growth factors had been identified in numerous physiological and pathological contexts. EGF binds to a cell surface EGF receptor, which induces a biochemical modification (phosphorylation) of the receptor's cytoplasmic tail. There is a growing consensus in the research community that, in addition to cellular and molecular studies, the dynamics of the EGFR network and its operation must be examined in tissues. A key challenge is to integrate the existing molecular and cellular information into a system-level description of the EGFR network at the tissue and organism level. In this paper, the two examples of EGFR signaling in tissues are described, and the recent efforts to model EGFR autocrine loops, which is a predominant mode of EGFR activation in vivo, are summarized.

  2. GDF11 forms a bone morphogenetic protein 1-activated latent complex that can modulate nerve growth factor-induced differentiation of PC12 cells.

    PubMed

    Ge, Gaoxiang; Hopkins, Delana R; Ho, Wen-Bin; Greenspan, Daniel S

    2005-07-01

    All transforming growth factor beta (TGF-beta) superfamily members are synthesized as precursors with prodomain sequences that are proteolytically removed by subtilisin-like proprotein convertases (SPCs). For most superfamily members, this is believed sufficient for activation. Exceptions are TGF-betas 1 to 3 and growth differentiation factor 8 (GDF8), also known as myostatin, which form noncovalent, latent complexes with their SPC-cleaved prodomains. Sequence similarities between TGF-betas 1 to 3, myostatin, and superfamily member GDF11, also known as bone morphogenetic protein 11 (BMP11), prompted us to examine whether GDF11 might be capable of forming a latent complex with its cleaved prodomain. Here we demonstrate that GDF11 forms a noncovalent latent complex with its SPC-cleaved prodomain and that this latent complex is activated via cleavage at a single specific site by members of the developmentally important BMP1/Tolloid family of metalloproteinases. Evidence is provided for a molecular model whereby formation and activation of this complex may play a general role in modulating neural differentiation. In particular, mutant GDF11 prodomains impervious to cleavage by BMP1/Tolloid proteinases are shown to be potent stimulators of neurodifferentiation, with potential for therapeutic applications.

  3. GDF11 Forms a Bone Morphogenetic Protein 1-Activated Latent Complex That Can Modulate Nerve Growth Factor-Induced Differentiation of PC12 Cells

    PubMed Central

    Ge, Gaoxiang; Hopkins, Delana R.; Ho, Wen-Bin; Greenspan, Daniel S.

    2005-01-01

    All transforming growth factor β (TGF-β) superfamily members are synthesized as precursors with prodomain sequences that are proteolytically removed by subtilisin-like proprotein convertases (SPCs). For most superfamily members, this is believed sufficient for activation. Exceptions are TGF-βs 1 to 3 and growth differentiation factor 8 (GDF8), also known as myostatin, which form noncovalent, latent complexes with their SPC-cleaved prodomains. Sequence similarities between TGF-βs 1 to 3, myostatin, and superfamily member GDF11, also known as bone morphogenetic protein 11 (BMP11), prompted us to examine whether GDF11 might be capable of forming a latent complex with its cleaved prodomain. Here we demonstrate that GDF11 forms a noncovalent latent complex with its SPC-cleaved prodomain and that this latent complex is activated via cleavage at a single specific site by members of the developmentally important BMP1/Tolloid family of metalloproteinases. Evidence is provided for a molecular model whereby formation and activation of this complex may play a general role in modulating neural differentiation. In particular, mutant GDF11 prodomains impervious to cleavage by BMP1/Tolloid proteinases are shown to be potent stimulators of neurodifferentiation, with potential for therapeutic applications. PMID:15988002

  4. XRP44X, an Inhibitor of Ras/Erk Activation of the Transcription Factor Elk3, Inhibits Tumour Growth and Metastasis in Mice

    PubMed Central

    Cheung, Henry; Tourrette, Yves; Maas, Peter; Schalken, Jack A; van der Pluijm, Gabri

    2016-01-01

    Transcription factors have an important role in cancer but are difficult targets for the development of tumour therapies. These factors include the Ets family, and in this study Elk3 that is activated by Ras oncogene /Erk signalling, and is involved in angiogenesis, malignant progression and epithelial-mesenchymal type processes. We previously described the identification and in-vitro characterisation of an inhibitor of Ras / Erk activation of Elk3 that also affects microtubules, XRP44X. We now report an initial characterisation of the effects of XRP44X in-vivo on tumour growth and metastasis in three preclinical models mouse models, subcutaneous xenografts, intra-cardiac injection-bone metastasis and the TRAMP transgenic mouse model of prostate cancer progression. XRP44X inhibits tumour growth and metastasis, with limited toxicity. Tumours from XRP44X-treated animals have decreased expression of genes containing Elk3-like binding motifs in their promoters, Elk3 protein and phosphorylated Elk3, suggesting that perhaps XRP44X acts in part by inhibiting the activity of Elk3. Further studies are now warranted to develop XRP44X for tumour therapy. PMID:27427904

  5. Identification of the cAMP response element that controls transcriptional activation of the insulin-like growth factor-I gene by prostaglandin E2 in osteoblasts

    NASA Technical Reports Server (NTRS)

    Thomas, M. J.; Umayahara, Y.; Shu, H.; Centrella, M.; Rotwein, P.; McCarthy, T. L.

    1996-01-01

    Insulin-like growth factor-I (IGF-I), a multifunctional growth factor, plays a key role in skeletal growth and can enhance bone cell replication and differentiation. We previously showed that prostaglandin E2 (PGE2) and other agents that increase cAMP activated IGF-I gene transcription in primary rat osteoblast cultures through promoter 1 (P1), the major IGF-I promoter, and found that transcriptional induction was mediated by protein kinase A. We now have identified a short segment of P1 that is essential for full hormonal regulation and have characterized inducible DNA-protein interactions involving this site. Transient transfections of IGF-I P1 reporter genes into primary rat osteoblasts showed that the 328-base pair untranslated region of exon 1 was required for a full 5.3-fold response to PGE2; mutation in a previously footprinted site, HS3D (base pairs +193 to +215), reduced induction by 65%. PGE2 stimulated nuclear protein binding to HS3D. Binding, as determined by gel mobility shift assay, was not seen in nuclear extracts from untreated osteoblast cultures, was detected within 2 h of PGE2 treatment, and was maximal by 4 h. This DNA-protein interaction was not observed in cytoplasmic extracts from PGE2-treated cultures, indicating nuclear localization of the protein kinase A-activated factor(s). Activation of this factor was not blocked by cycloheximide (Chx), and Chx did not impair stimulation of IGF-I gene expression by PGE2. In contrast, binding to a consensus cAMP response element (CRE; 5'-TGACGTCA-3') from the rat somatostatin gene was not modulated by PGE2 or Chx. Competition gel mobility shift analysis using mutated DNA probes identified 5'-CGCAATCG-3' as the minimal sequence needed for inducible binding. All modified IGF-I P1 promoterreporter genes with mutations within this CRE sequence also showed a diminished functional response to PGE2. These results identify the CRE within the 5'-untranslated region of IGF-I exon 1 that is required for hormonal

  6. A comparison of the effects of unfractionated heparin, dalteparin and danaparoid on vascular endothelial growth factor-induced tumour angiogenesis and heparanase activity

    PubMed Central

    Takahashi, Hidenori; Ebihara, Satoru; Okazaki, Tatsuma; Asada, Masanori; Sasaki, Hidetada; Yamaya, Mutsuo

    2005-01-01

    Disseminated intravascular coagulation (DIC) is the most common complication of solid tumours. In this study, the effectiveness of three polysaccharide anticoagulants (PSAs), at therapeutic doses, at inhibiting solid tumour growth was investigated. Mice with tumour xenografts were subcutaneously injected with either unfractionated heparin (UFH; 200 units kg−1 day−1), dalteparin (75 units kg−1 day−1) or danaparoid (50 units kg−1 day−1). At these concentrations, these PSAs are equieffective at inhibiting blood coagulation activated factor X. In mice with Lewis lung carcinoma (LLC) tumours dalteparin and, to a lesser extent, UFH inhibited both tumour growth and angiogenesis, whereas danaparoid did not. In contrast, in mice with KLN205 tumours, all the PSAs inhibited tumour growth and angiogenesis. All the PSAs significantly inhibited proliferation, migration of endothelial cells and vessel formation in matrigel plugs containing vascular endothelial growth factor (VEGF) and there were no significant differences between these effects of the PSAs. The PSAs had no effect on endothelial cell tubular formation in vitro. Although all the PSAs inhibited VEGF production in KLN205 tumours in vivo and cells in vitro, in LLC tumours and cells only UFH and dalteparin inhibited VEGF production, whereas danaparoid did not. In both LLC and KLN205 tumours in vivo, heparanase activity was inhibited by UFH and dalteparin, but not by danaparoid. Hence, UFH and dalteparin may be more effective than danaparoid at inhibiting cancer progression in DIC patients with solid tumours, due at least in part to their ability to suppress VEGF and heparanase in tumours. PMID:16041398

  7. A comparison of the effects of unfractionated heparin, dalteparin and danaparoid on vascular endothelial growth factor-induced tumour angiogenesis and heparanase activity.

    PubMed

    Takahashi, Hidenori; Ebihara, Satoru; Okazaki, Tatsuma; Asada, Masanori; Sasaki, Hidetada; Yamaya, Mutsuo

    2005-10-01

    Disseminated intravascular coagulation (DIC) is the most common complication of solid tumours. In this study, the effectiveness of three polysaccharide anticoagulants (PSAs), at therapeutic doses, at inhibiting solid tumour growth was investigated. Mice with tumour xenografts were subcutaneously injected with either unfractionated heparin (UFH; 200 units kg(-1) day(-1)), dalteparin (75 units kg(-1) day(-1)) or danaparoid (50 units kg(-1) day(-1)). At these concentrations, these PSAs are equieffective at inhibiting blood coagulation activated factor X. In mice with Lewis lung carcinoma (LLC) tumours dalteparin and, to a lesser extent, UFH inhibited both tumour growth and angiogenesis, whereas danaparoid did not. In contrast, in mice with KLN205 tumours, all the PSAs inhibited tumour growth and angiogenesis. All the PSAs significantly inhibited proliferation, migration of endothelial cells and vessel formation in matrigel plugs containing vascular endothelial growth factor (VEGF) and there were no significant differences between these effects of the PSAs. The PSAs had no effect on endothelial cell tubular formation in vitro. Although all the PSAs inhibited VEGF production in KLN205 tumours in vivo and cells in vitro, in LLC tumours and cells only UFH and dalteparin inhibited VEGF production, whereas danaparoid did not. In both LLC and KLN205 tumours in vivo, heparanase activity was inhibited by UFH and dalteparin, but not by danaparoid. Hence, UFH and dalteparin may be more effective than danaparoid at inhibiting cancer progression in DIC patients with solid tumours, due at least in part to their ability to suppress VEGF and heparanase in tumours. PMID:16041398

  8. Vascular endothelial growth factor regulates myeloid cell leukemia-1 expression through neuropilin-1-dependent activation of c-MET signaling in human prostate cancer cells

    PubMed Central

    2010-01-01

    Background Myeloid cell leukemia-1 (Mcl-1) is a member of the Bcl-2 family, which inhibits cell apoptosis by sequestering pro-apoptotic proteins Bim and Bid. Mcl-1 overexpression has been associated with progression in leukemia and some solid tumors including prostate cancer (PCa). However, the regulatory mechanism for Mcl-1 expression in PCa cells remains elusive. Results Immunohistochemical analyses revealed that Mcl-1 expression was elevated in PCa specimens with high Gleason grades and further significantly increased in bone metastasis, suggesting a pivotal role of Mcl-1 in PCa metastasis. We further found that vascular endothelial growth factor (VEGF) is a novel regulator of Mcl-1 expression in PCa cells. Inhibition of endogenous Mcl-1 induced apoptosis, indicating that Mcl-1 is an important survival factor in PCa cells. Neuropilin-1 (NRP1), the "co-receptor" for VEGF165 isoform, was found to be highly expressed in PCa cells, and indispensible in the regulation of Mcl-1. Intriguingly, VEGF165 promoted physical interaction between NRP1 and hepatocyte growth factor (HGF) receptor c-MET, and facilitated c-MET phosphorylation via a NRP1-dependent mechanism. VEGF165 induction of Mcl-1 may involve rapid activation of Src kinases and signal transducers and activators of transcription 3 (Stat3). Importantly, NRP1 overexpression and c-MET activation were positively associated with progression and bone metastasis in human PCa specimens and xenograft tissues. Conclusions This study demonstrated that Mcl-1 overexpression is associated with PCa bone metastasis. Activation of VEGF165-NRP1-c-MET signaling could confer PCa cells survival advantages by up-regulating Mcl-1, contributing to PCa progression. PMID:20085644

  9. Growth Factors in Proliferative Diabetic Retinopathy

    PubMed Central

    Khan, Zia Ali

    2003-01-01

    Many growth factors are implicated in the pathogenesis of proliferative diabetic retinopathy. Alteration of growth factors and their receptors in diabetes has been shown in both experimental and clinical studies. Sustained hyperglycemia resulting from long-standing diabetes leads to several biochemical abnormalities that consequently result in retinal hypoxia. Retinal oxygenation state regulates various growth factors that promote angiogenesis in order to meet the oxygen demands of the tissue. However, unregulated expression of these growth factors and induction of complex cascades leading to augmentation of other proangiogenic factors, which may not be regulated by tissue oxygenation, leads to uncontrolled retinal neovascularization and blindness in diabetic patients. PMID:14668050

  10. First report of the pituitary adenylate cyclase activating polypeptide (PACAP) in crustaceans: conservation of its functions as growth promoting factor and immunomodulator in the white shrimp Litopenaeus vannamei.

    PubMed

    Lugo, Juana María; Carpio, Yamila; Morales, Reynold; Rodríguez-Ramos, Tania; Ramos, Laida; Estrada, Mario Pablo

    2013-12-01

    The high conservation of the pituitary adenylate cyclase activating polypeptide (PACAP) sequence indicates that this peptide fulfills important biological functions in a broad spectrum of organisms. However, in invertebrates, little is known about its presence and its functions remain unclear. Up to now, in non-mammalian vertebrates, the majority of studies on PACAP have focused mainly on the localization, cloning and structural evolution of this peptide. As yet, little is known about its biological functions as growth factor and immunomodulator in lower vertebrates. Recently, we have shown that PACAP, apart from its neuroendocrine role, influences immune functions in larval and juvenile fish. In this work, we isolated for the first time the cDNA encoding the mature PACAP from a crustacean species, the white shrimp Litopenaeus vannamei, corroborating its high degree of sequence conservation, when compared to sequences reported from tunicates to mammalian vertebrates. Based on this, we have evaluated the effects of purified recombinant Clarias gariepinus PACAP administrated by immersion baths on white shrimp growth and immunity. We demonstrated that PACAP improves hemocyte count, superoxide dismutase, lectins and nitric oxide synthase derived metabolites in treated shrimp related with an increase in total protein concentration and growth performance. From our results, PACAP acts as a regulator of shrimp growth and immunity, suggesting that in crustaceans, as in vertebrate organisms, PACAP is an important molecule shared by both the endocrine and the immune systems.

  11. Insulin-like growth factor 1 receptor and p38 mitogen-activated protein kinase signals inversely regulate signal transducer and activator of transcription 3 activity to control human dental pulp stem cell quiescence, propagation, and differentiation.

    PubMed

    Vandomme, Jerome; Touil, Yasmine; Ostyn, Pauline; Olejnik, Cecile; Flamenco, Pilar; El Machhour, Raja; Segard, Pascaline; Masselot, Bernadette; Bailliez, Yves; Formstecher, Pierre; Polakowska, Renata

    2014-04-15

    Dental pulp stem cells (DPSCs) remain quiescent until activated in response to severe dental pulp damage. Once activated, they exit quiescence and enter regenerative odontogenesis, producing reparative dentin. The factors and signaling molecules that control the quiescence/activation and commitment to differentiation of human DPSCs are not known. In this study, we determined that the inhibition of insulin-like growth factor 1 receptor (IGF-1R) and p38 mitogen-activated protein kinase (p38 MAPK) signaling commonly activates DPSCs and promotes their exit from the G0 phase of the cell cycle as well as from the pyronin Y(low) stem cell compartment. The inhibition of these two pathways, however, inversely determines DPSC fate. In contrast to p38 MAPK inhibitors, IGF-1R inhibitors enhance dental pulp cell sphere-forming capacity and reduce the cells' colony-forming capacity without inducing cell death. The inverse cellular changes initiated by IGF-1R and p38 MAPK inhibitors were accompanied by inverse changes in the levels of active signal transducer and activator of transcription 3 (STAT3) factor, inactive glycogen synthase kinase 3, and matrix extracellular phosphoglycoprotein, a marker of early odontoblast differentiation. Our data suggest that there is cross talk between the IGF-1R and p38 MAPK signaling pathways in DPSCs and that the signals provided by these pathways converge at STAT3 and inversely regulate its activity to maintain quiescence or to promote self-renewal and differentiation of the cells. We propose a working model that explains the possible interactions between IGF-1R and p38 MAPK at the molecular level and describes the cellular consequences of these interactions. This model may inspire further fundamental study and stimulate research on the clinical applications of DPSC in cellular therapy and tissue regeneration. PMID:24266654

  12. The transcription factor paired-related homeobox 1 (Prrx1) inhibits adipogenesis by activating transforming growth factor-β (TGFβ) signaling.

    PubMed

    Du, Baowen; Cawthorn, William P; Su, Alison; Doucette, Casey R; Yao, Yao; Hemati, Nahid; Kampert, Sarah; McCoin, Colin; Broome, David T; Rosen, Clifford J; Yang, Gongshe; MacDougald, Ormond A

    2013-02-01

    Differentiation of adipocytes from preadipocytes contributes to adipose tissue expansion in obesity. Impaired adipogenesis may underlie the development of metabolic diseases such as insulin resistance and type 2 diabetes. Mechanistically, a well defined transcriptional network coordinates adipocyte differentiation. The family of paired-related homeobox transcription factors, which includes Prrx1a, Prrx1b, and Prrx2, is implicated with regulation of mesenchymal cell fate, including myogenesis and skeletogenesis; however, whether these proteins impact adipogenesis remains to be addressed. In this study, we identify Prrx1a and Prrx1b as negative regulators of adipogenesis. We show that Prrx1a and Prrx1b are down-regulated during adipogenesis in vitro and in vivo. Stable knockdown of Prrx1a/b enhances adipogenesis, with increased expression of peroxisome proliferator-activated receptor-γ, CCAAT/enhancer-binding protein-α and FABP4 and increased secretion of the adipokines adiponectin and chemerin. Although stable low-level expression of Prrx1a, Prrx1b, or Prrx2 does not affect 3T3-L1 adipogenesis, transient overexpression of Prrx1a or Prrx1b inhibits peroxisome proliferator-activated receptor-γ activity. Prrx1 knockdown decreases expression of Tgfb2 and Tgfb3, and inhibition of TGFβ signaling during adipogenesis mimics the effects of Prrx1 knockdown. These data support the hypothesis that endogenous Prrx1 restrains adipogenesis by regulating expression of TGFβ ligands and thereby activating TGFβ signaling. Finally, we find that expression of Prrx1a or Prrx1b in adipose tissue increases during obesity and strongly correlates with Tgfb3 expression in BL6 mice. These observations suggest that increased Prrx1 expression may promote TGFβ activity in adipose tissue and thereby contribute to aberrant adipocyte function during obesity.

  13. Elevated SP-1 transcription factor expression and activity drives basal and hypoxia-induced vascular endothelial growth factor (VEGF) expression in non-small cell lung cancer.

    PubMed

    Deacon, Karl; Onion, David; Kumari, Rajendra; Watson, Susan A; Knox, Alan J

    2012-11-16

    VEGF plays a central role in angiogenesis in cancer. Non-small cell lung cancer (NSCLC) tumors have increased microvascular density, localized hypoxia, and high VEGF expression levels; however, there is a lack of understanding of how oncogenic and tumor microenvironment changes such as hypoxia lead to greater VEGF expression in lung and other cancers. We show that NSCLC cells secreted higher levels of VEGF than normal airway epithelial cells. Actinomycin D inhibited all NSCLC VEGF secretion, and VEGF minimal promoter-luciferase reporter constructs were constitutively active until the last 85 base pairs before the transcription start site containing three SP-1 transcription factor-binding sites; mutation of these VEGF promoter SP-1-binding sites eliminated VEGF promoter activity. Furthermore, dominant negative SP-1, mithramycin A, and SP-1 shRNA decreased VEGF promoter activity, whereas overexpression of SP-1 increased VEGF promoter activity. Chromatin immunoprecipitation assays demonstrated SP-1, p300, and PCA/F histone acetyltransferase binding and histone H4 hyperacetylation at the VEGF promoter in NSCLC cells. Cultured NSCLC cells expressed higher levels of SP-1 protein than normal airway epithelial cells, and double-fluorescence immunohistochemistry showed a strong correlation between SP-1 and VEGF in human NSCLC tumors. In addition, hypoxia-driven VEGF expression in NSCLC cells was SP-1-dependent, with hypoxia increasing SP-1 activity and binding to the VEGF promoter. These studies are the first to demonstrate that overexpression of SP-1 plays a central role in hypoxia-induced VEGF secretion. PMID:22992725

  14. A benzoxazine derivative induces vascular endothelial cell apoptosis in the presence of fibroblast growth factor-2 by elevating NADPH oxidase activity and reactive oxygen species levels.

    PubMed

    Zhao, Jing; He, Qiuxia; Cheng, Yizhe; Zhao, Baoxiang; Zhang, Yun; Zhang, Shangli; Miao, Junying

    2009-09-01

    Previously, we found that 6,8-dichloro-2,3-dihydro-3-hydroxymethyl-1,4-benzoxazine (DBO) promoted apoptosis of human umbilical vascular endothelial cells (HUVECs) deprived of growth factors. In this study, we aimed to investigate the effect of DBO and its mechanism of action on angiogenesis and apoptosis of HUVECs in the presence of fibroblast growth factor-2 (FGF-2), which promotes angiogenesis and inhibits apoptosis in vivo and in vitro. DBO significantly inhibited capillary-like tube formation by promoting apoptosis of HUVECs in the presence of FGF-2 in vitro. Furthermore, DBO elevated the levels of reactive oxygen species (ROS) and nitric oxide (NO) and increased the activity of NADPH oxidase and inducible nitric oxide synthase (iNOS) in promoting apoptosis under this condition. Moreover, when NADPH oxidase was inhibited by its specific inhibitor, dibenziodolium chloride (DPI), DBO could not elevate ROS and NO levels in HUVECs. The data suggest that DBO is a new modulator of apoptosis in vitro, and it might function by increasing the activity of NADPH oxidase and iNOS, subsequently elevating the levels of ROS and NO in HUVECs. The findings of this study provide a new small molecule for investigating the FGF-2/NADPH oxidase/iNOS signaling pathway in apoptosis.

  15. Keratinocyte growth factor and hepatocyte growth factor/scatter factor are heparin-binding growth factors for alveolar type II cells in fibroblast-conditioned medium.

    PubMed Central

    Panos, R J; Rubin, J S; Csaky, K G; Aaronson, S A; Mason, R J

    1993-01-01

    Epithelial-mesenchymal interactions mediate aspects of normal lung growth and development and are important in the restoration of normal alveolar architecture after lung injury. To determine if fibroblasts are a source of soluble growth factors for alveolar type II cells, we investigated the effect of fibroblast-conditioned medium (CM) on alveolar type II cell DNA synthesis. Serum-free CM from confluent adult human lung fibroblasts was concentrated fivefold by lyophilization. Type II cells were isolated from adult rats by elastase dissociation and incubated with [3H]thymidine and varying dilutions of concentrated CM and serum from day 1 to 3 of culture. Stimulation of type II cell DNA synthesis by fibroblast-CM was maximal after 48 h of conditioning and required the presence of serum. The activity of the CM was eliminated by boiling and by treatment with trypsin, pepsin, or dithiothreitol and was additive with saturating concentrations of acidic fibroblast growth factor, epidermal growth factor, and insulin. The growth factor activity bound to heparin-Sepharose and was eluted with 0.6 and 1.0 M NaCl. Neutralizing antibody studies demonstrated that the primary mitogens isolated in the 0.6 and 1.0 M NaCl fractions were keratinocyte growth factor (KGF, fibroblast growth factor 7) and hepatocyte growth factor/scatter factor (HGF/SF), respectively. HGF/SF was demonstrated in the crude CM and KGF was detected in the 0.6 M NaCl eluent by immunoblotting. Northern blot analysis confirmed that the lung fibroblasts expressed both KGF and HGF/SF transcripts. Human recombinant KGF and HGF/SF induced a concentration- and serum-dependent increase in rat alveolar type II cell DNA synthesis. We conclude that adult human lung fibroblasts produce at least two soluble heparin-binding growth factors, KGF and HGF/SF, which promote DNA synthesis and proliferation of rat alveolar type II cells in primary culture. KGF and HGF/SF may be important stimuli for alveolar type II cell

  16. Irradiation-Induced Regulation of Plasminogen Activator Inhibitor Type-1 and Vascular Endothelial Growth Factor in Six Human Squamous Cell Carcinoma Lines of the Head and Neck

    SciTech Connect

    Artman, Tuuli; Schilling, Daniela; Multhoff, Gabriele

    2010-02-01

    Purpose: It has been shown that plasminogen activator inhibitor type-1 (PAI-1) and vascular endothelial growth factor (VEGF) are involved in neo-angiogenesis. The aim of this study was to investigate the irradiation-induced regulation of PAI-1 and VEGF in squamous cell carcinomas of the head and neck (SCCHN) cell lines of varying radiation sensitivity. Methods and Materials: Six cell lines derived from SCCHN were investigated in vitro. The colorimetric AlamarBlue assay was used to detect metabolic activity of cell lines during irradiation as a surrogate marker for radiation sensitivity. PAI-1 and VEGF secretion levels were measured by enzyme-linked immunosorbent assay 24, 48, and 72 h after irradiation with 0, 2, 6, and 10 Gy. The direct radioprotective effect of exogenous PAI-1 was measured using the clonogenic assay. For regulation studies, transforming growth factor-beta1 (TGF-beta1), hypoxia-inducible factor-1alpha (HIF-1alpha), hypoxia-inducible factor-2alpha (HIF-2alpha), or both HIF-1alpha and HIF-2alpha were downregulated using siRNA. Results: Although baseline levels varied greatly, irradiation led to a comparable dose-dependent increase in PAI-1 and VEGF secretion in all six cell lines. Addition of exogenous stable PAI-1 to the low PAI-1-expressing cell lines, XF354 and FaDu, did not lead to a radioprotective effect. Downregulation of TGF-beta1 significantly decreased VEGF secretion in radiation-sensitive XF354 cells, and downregulation of HIF-1alpha and HIF-2alpha reduced PAI-1 and VEGF secretion in radiation-resistant SAS cells. Conclusions: Irradiation dose-dependently increased PAI-1 and VEGF secretion in all SCCHN cell lines tested regardless of their basal levels and radiation sensitivity. In addition, TGF-beta1 and HIF-1alpha could be partly responsible for VEGF and PAI-1 upregulation after irradiation.

  17. A Novel Cysteine-Rich Neurotrophic Factor in "Aplysia" Facilitates Growth, MAPK Activation, and Long-Term Synaptic Facilitation

    ERIC Educational Resources Information Center

    Pu, Lu; Kopec, Ashley M.; Boyle, Heather D.; Carew, Thomas J.

    2014-01-01

    Neurotrophins are critically involved in developmental processes such as neuronal cell survival, growth, and differentiation, as well as in adult synaptic plasticity contributing to learning and memory. Our previous studies examining neurotrophins and memory formation in "Aplysia" showed that a TrkB ligand is required for MAPK…

  18. Synthetic heparin-binding growth factor analogs

    DOEpatents

    Pena, Louis A.; Zamora, Paul; Lin, Xinhua; Glass, John D.

    2007-01-23

    The invention provides synthetic heparin-binding growth factor analogs having at least one peptide chain that binds a heparin-binding growth factor receptor, covalently bound to a hydrophobic linker, which is in turn covalently bound to a non-signaling peptide that includes a heparin-binding domain. The synthetic heparin-binding growth factor analogs are useful as soluble biologics or as surface coatings for medical devices.

  19. Epstein-Barr virus LMP1 induction of the epidermal growth factor receptor is mediated through a TRAF signaling pathway distinct from NF-kappaB activation.

    PubMed Central

    Miller, W E; Mosialos, G; Kieff, E; Raab-Traub, N

    1997-01-01

    The Epstein-Barr virus (EBV)-encoded LMP1 protein induces several cellular changes including induction of epidermal growth factor receptor (EGFR) expression and activation of the NF-kappaB transcription factor. Two domains within the carboxy terminus have been identified that activate NF-kappaB. In this study, mutational analysis of the LMP1 protein indicated that the proximal NF-kappaB activation domain, which is identical to the TRAF interaction domain (amino acids 187 to 231), is essential for induction of the EGFR. The distal NF-kappaB activation domain (amino acids 352 to 386) did not induce expression of the EGFR. In contrast, the two domains both independently activated a kappaB-CAT reporter gene and induced expression of the NF-kappaB-regulated A20 gene in C33A epithelial cells. These results indicate that induction of the EGFR by LMP1 involves the TRAF interaction domain and that activation of NF-kappaB alone is not sufficient. Northern blot analysis revealed that induction of EGFR and A20 expression is likely to be at the transcriptional level. Interestingly expression of CD40 in the C33A cells also induced expression of the EGFR. Overexpression of either TRAF3 or an amino-terminal-truncated form of TRAF3 (TRAF3-C) inhibited signaling from the LMP1 TRAF interaction domain but did not affect signaling from the distal NF-kappaB activation domain. These data further define the mechanism by which LMP1 induces expression of the EGFR and indicate that TRAF signaling from LMP1 and CD40 activates a downstream transcription pathway distinct from NF-kappaB that induces expression of the EGFR. PMID:8985387

  20. Date syrup-derived polyphenols attenuate angiogenic responses and exhibits anti-inflammatory activity mediated by vascular endothelial growth factor and cyclooxygenase-2 expression in endothelial cells.

    PubMed

    Taleb, Hajer; Morris, R Keith; Withycombe, Cathryn E; Maddocks, Sarah E; Kanekanian, Ara D

    2016-07-01

    Bioactive components such as polyphenols, present in many plants, are purported to have anti-inflammatory and antiangiogenic properties. Date syrup, produced from date fruit of the date palm tree, has traditionally been used to treat a wide range of diseases with etiologies involving angiogenesis and inflammation. It was hypothesized that polyphenols in date syrup reduce angiogenic responses such as cell migration, tube formation, and matrix metalloproteinase activity in an inflammatory model by exhibiting anti-inflammatory activity mediated by vascular endothelial growth factor (VEGF) and the prostaglandin enzyme cyclooxygenase-2 (COX-2) in endothelial cells. Date syrup polyphenols at 60 and 600μg/mL reduced inflammation and suppressed several stages of angiogenesis, including endothelial cell migration, invasion, matrix metalloproteinase activity, and tube formation, without evidence of cytotoxicity. VEGF and COX-2 expression induced by tumor necrosis factor-alpha at both gene expression and protein level was significantly reduced by date syrup polyphenols in comparison to untreated cells. In conclusion, polyphenols in date syrup attenuated angiogenic responses and exhibited anti-inflammatory activity mediated by VEGF and COX-2 expression in endothelial cells. PMID:27333954

  1. A novel, selective inhibitor of fibroblast growth factor receptors that shows a potent broad spectrum of antitumor activity in several tumor xenograft models.

    PubMed

    Zhao, Genshi; Li, Wei-Ying; Chen, Daohong; Henry, James R; Li, Hong-Yu; Chen, Zhaogen; Zia-Ebrahimi, Mohammad; Bloem, Laura; Zhai, Yan; Huss, Karen; Peng, Sheng-Bin; McCann, Denis J

    2011-11-01

    The fibroblast growth factor receptors (FGFR) are tyrosine kinases that are present in many types of endothelial and tumor cells and play an important role in tumor cell growth, survival, and migration as well as in maintaining tumor angiogenesis. Overexpression of FGFRs or aberrant regulation of their activities has been implicated in many forms of human malignancies. Therefore, targeting FGFRs represents an attractive strategy for development of cancer treatment options by simultaneously inhibiting tumor cell growth, survival, and migration as well as tumor angiogenesis. Here, we describe a potent, selective, small-molecule FGFR inhibitor, (R)-(E)-2-(4-(2-(5-(1-(3,5-Dichloropyridin-4-yl)ethoxy)-1H-indazol-3yl)vinyl)-1H-pyrazol-1-yl)ethanol, designated as LY2874455. This molecule is active against all 4 FGFRs, with a similar potency in biochemical assays. It exhibits a potent activity against FGF/FGFR-mediated signaling in several cancer cell lines and shows an excellent broad spectrum of antitumor activity in several tumor xenograft models representing the major FGF/FGFR relevant tumor histologies including lung, gastric, and bladder cancers and multiple myeloma, and with a well-defined pharmacokinetic/pharmacodynamic relationship. LY2874455 also exhibits a 6- to 9-fold in vitro and in vivo selectivity on inhibition of FGF- over VEGF-mediated target signaling in mice. Furthermore, LY2874455 did not show VEGF receptor 2-mediated toxicities such as hypertension at efficacious doses. Currently, this molecule is being evaluated for its potential use in the clinic.

  2. Activation of H-Ras and Rac1 correlates with epidermal growth factor-induced invasion in Hs578T and MDA-MB-231 breast carcinoma cells.

    PubMed

    Koh, Min-Soo; Moon, Aree

    2011-03-01

    There is considerable experimental evidence that hyperactive Ras proteins promote breast cancer growth and development including invasiveness, despite the low frequency of mutated forms of Ras in breast cancer. We have previously shown that H-Ras, but not N-Ras, induces an invasive phenotype mediated by small GTPase Rac1 in MCF10A human breast epithelial cells. Epidermal growth factor (EGF) plays an important role in aberrant growth and metastasis formation of many tumor types including breast cancer. The present study aims to investigate the correlation between EGF-induced invasiveness and Ras activation in four widely used breast cancer cell lines. Upon EGF stimulation, invasive abilities and H-Ras activation were significantly increased in Hs578T and MDA-MB-231 cell lines, but not in MDA-MB-453 and T47D cell lines. Using small interfering RNA (siRNA) to target H-Ras, we showed a crucial role of H-Ras in the invasive phenotype induced by EGF in Hs578T and MDA-MB-231 cells. Moreover, siRNA-knockdown of Rac1 significantly inhibited the EGF-induced invasiveness in these cells. Taken together, this study characterized human breast cancer cell lines with regard to the relationship between H-Ras activation and the invasive phenotype induced by EGF. Our data demonstrate that the activation of H-Ras and the downstream molecule Rac1 correlates with EGF-induced breast cancer cell invasion, providing important information on the regulation of malignant progression in mammary carcinoma cells.

  3. Epidermal growth factor receptor not equal to nerve growth factor.

    PubMed

    Williams, L R

    1989-01-01

    I am perplexed by the authors' complete lack of definition of neurotrophic factors. The agents Butcher and Woolf want to blame are neurite promoting factors, not neurotrophic factors. Treatment of Alzheimer's disease with NGF antagonists might instead exacerbate the death of both basal forebrain neurons and their cortical target neurons, accelerating the progress of dementia.

  4. Identification of Follistatin-Like 1 by Expression Cloning as an Activator of the Growth Differentiation Factor 15 Gene and a Prognostic Biomarker in Acute Coronary Syndrome

    PubMed Central

    Widera, Christian; Giannitsis, Evangelos; Kempf, Tibor; Korf-Klingebiel, Mortimer; Fiedler, Beate; Sharma, Sarita; Katus, Hugo A.; Asaumi, Yasuhide; Shimano, Masayuki; Walsh, Kenneth; Wollert, Kai C.

    2012-01-01

    BACKGROUND Growth differentiation factor 15 (GDF15) is a stress-responsive cytokine and biomarker that is produced after myocardial infarction and that is related to prognosis in acute coronary syndrome (ACS). We hypothesized that secreted proteins that activate GDF15 production may represent new ACS biomarkers. METHODS We expressed clones from an infarcted mouse heart cDNA library in COS1 cells and assayed for activation of a luciferase reporter gene controlled by a 642-bp fragment of the mouse growth differentiation factor 15 (GDF15) gene promoter. We measured the circulating concentrations of follistatin-like 1 (FSTL1) and GDF15 in 1369 patients with ACS. RESULTS One cDNA clone that activated the GDF15 promoter–luciferase reporter encoded the secreted protein FSTL1. Treatment with FSTL1 activated GDF15 production in cultured cardiomyocytes. Transgenic production of FSTL1 stimulated GDF15 production in the murine heart, whereas cardiomyocyte-selective deletion of FSTL1 decreased production of GDF15 in cardiomyocytes, indicating that FSTL1 is sufficient and required for GDF15 production. In ACS, FSTL1 emerged as the strongest independent correlate of GDF15 (partial R2 = 0.26). A total of 106 patients died of a cardiovascular cause during a median follow-up of 252 days. Patients with an FSTL1 concentration in the top quartile had a 3.7-fold higher risk of cardiovascular death compared with patients in the first 3 quartiles (P < 0.001). FSTL1 remained associated with cardiovascular death after adjustment for clinical, angiographic, and biochemical variables. CONCLUSIONS Our study is the first to use expression cloning for biomarker discovery upstream of a gene of interest and to identify FSTL1 as an independent prognostic biomarker in ACS. PMID:22675198

  5. Adenoviral delivery of an antisense RNA complementary to the 3' coding sequence of transforming growth factor-beta1 inhibits fibrogenic activities of hepatic stellate cells.

    PubMed

    Arias, Monica; Lahme, Birgit; Van de Leur, Eddy; Gressner, Axel M; Weiskirchen, Ralf

    2002-06-01

    Liver fibrosis occurs as a consequence of the transdifferentiationof hepatic stellate cells into myofibroblasts and is associated with an increased expression and activation of transforming growth factor (TGF)-beta1. This pluripotent, profibrogenic cytokine stimulates matrix synthesis and decreases matrix degradation, resulting in fibrosis. Thus, blockade of synthesis or sequestering of mature TGF-beta1 is a primary target for the development of antifibrotic approaches. The purpose of this study was to investigate whether the administration of adenoviruses constitutively expressing an antisense mRNA complementary to the 3' coding sequence of TGF-beta1 is able to suppress the synthesis of TGF-beta1 in culture-activated hepatic stellate cells. We demonstrate that the adenoviral vehicle directs high-level expression of the transgene and proved that the transduced antisense is biologically active by immunoprecipitation, Western blot, quantitative TGF-beta1 ELISA, and cell proliferation assays. Additionally, the biological function of the transgene was confirmed by analysis of differential activity of TGF-beta1-responsive genes using cell ELISA, Northern blotting, and by microarray technology, respectively. Furthermore, we examined the effects of that transgene on the expression of TGF-beta2, TGF-beta3, collagen type alpha1(I), latent transforming growth factor binding protein 1, types I and II TGF-beta receptors, and alpha-smooth muscle actin. Our results indicate that the administration of antisense mRNA offers a feasible approach to block autocrine TGF-beta1 signaling in hepatic stellate cells and may be useful and applicable in future to the treatment of fibrosis in chronic liver diseases.

  6. Inhibition of Transforming Growth Factor-Beta1 SignalingAttenuates Ataxia Telangiectasia Mutated Activity in Response toGenotoxic Stress

    SciTech Connect

    Kirshner, Julia; Jobling, Michael F.; Pajares, Maria Jose; Ravani, Shraddha A.; Glick, Adam; Lavin, Martin F.; Koslov, Sergei; Shiloh, Yosef; Barcellos-Hoff, Mary Helen

    2006-01-01

    Ionizing radiation causes DNA damage that elicits a cellular program of damage control coordinated by the kinase activity of ataxia telangiectasia mutated protein (ATM). Transforming growth factor {beta} (TGF{beta})-1, which is activated by radiation, is a potent and pleiotropic mediator of physiologic and pathologic processes. Here we show that TGF{beta} inhibition impedes the canonical cellular DNA damage stress response. Irradiated Tgf{beta}I null murine epithelial cells or human epithelial cells treated with a small-molecule inhibitor of TGF{beta} type I receptor kinase exhibit decreased phosphorylation of Chk2, Rad17, and p53; reduced H2AX radiation-induced foci; and increased radiosensitivity compared with TGF{beta} competent cells. We determined that loss of TGF{beta} signaling in epithelial cells truncated ATM autophosphorylation and significantly reduced its kinase activity, without affecting protein abundance. Addition of TGF{beta} restored functional ATM and downstream DNA damage responses. These data reveal a heretofore undetected critical link between the microenvironment and ATM, which directs epithelial cell stress responses, cell fate, and tissue integrity. Thus, Tgf{beta}I, in addition to its role in homoeostatic growth control, plays a complex role in regulating responses to genotoxic stress, the failure of which would contribute to the development of cancer; conversely, inhibiting TGF{beta} may be used to advantage in cancer therapy.

  7. Multiple receptor tyrosine kinase activation attenuates therapeutic efficacy of the fibroblast growth factor receptor 2 inhibitor AZD4547 in FGFR2 amplified gastric cancer

    PubMed Central

    Zhang, Zhe; Liu, Xinyang; Wu, Zheng; Geng, Ruixuan; Ge, Xiaoxiao; Dai, Congqi; Liu, Rujiao; Zhang, Qunling; Li, Wenhua; Li, Jin

    2015-01-01

    Fibroblast growth factor receptor 2 (FGFR2)-targeted therapy has attracted considerable attention as novel anticancer agents in gastric cancer (GC). However, intrinsic or acquired drug resistance has emerged as a major challenge to their clinical use. In this study, we demonstrated that several receptor tyrosine kinase (RTK), including EGFR, HER3 and MET, activations contributed to AZD4547 (a selective FGFR2 inhibitor) hyposensitivity in FGFR2 amplified GC cells. The rescue effect was abrogated by inhibiting these RTKs with their targeted tyrosine kinase inhibitors (TKIs). In addition, synergy in growth inhibition was observed when the GC cells were treated with a combination of AZD4547 and cetuximab (an EGFR monoclonal antibody) both in vitro and in vivo. More importantly, tissue microarray analysis revealed that these resistance-conferring RTKs were highly expressed in FGFR2 positive GC patients. Taken together, these observations demonstrated RTKs including EGFR, HER3 and MET activations as novel mechanisms of hyposensitivity to AZD4547. It will be clinically valuable to investigate the involvement of RTK-mediated signaling in intrinsicor acquired resistance to FGFR2 TKIs in GC. A combination targeted therapeutic strategy may be recommended for treating FGFR2 amplified GC patients with these RTK activations. PMID:25576915

  8. The catalytic domain of endogenous urokinase-type plasminogen activator is required for the mitogenic activity of platelet-derived and basic fibroblast growth factors in human vascular smooth muscle cells.

    PubMed

    Padró, Teresa; Mesters, Rolf M; Dankbar, Berno; Hintelmann, Heike; Bieker, Ralf; Kiehl, Michael; Berdel, Wolfgang E; Kienast, Joachim

    2002-05-01

    Emerging data suggest that urokinase-type plasminogen activator (UPA), beyond its role in pericellular proteolysis, may also act as a mitogen. We investigated the function of endogenous UPA in mediating the mitogenic effects of platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) on human vascular smooth muscle cells (SMC). Growth-arrested SMC constitutively expressed UPA, but UPA expression and secretion increased several times upon stimulation with either PDGF or bFGF. Inhibition of endogenous UPA with a polyclonal antibody significantly reduced DNA synthesis and proliferation of PDGF or bFGF stimulated SMC, this effect already being evident when the cells entered S-phase. The proliferative activity of endogenous UPA was dependent on a functional catalytic domain as demonstrated by inhibition experiments with a specific monoclonal antibody (394OA) and p-aminobenzamidine, respectively. In contrast, neither plasmin generation nor binding of UPA to its receptor (CD87) were required for UPA-mediated mitogenic effects. The results demonstrate that endogenous UPA is not only overexpressed in SMC upon stimulation with PDGF/bFGF, but also mediates the mitogenic activity of the growth factors in a catalytic-domain-dependent manner. Specific inhibition of this UPA domain may represent an attractive target for pharmacological interventions in atherogenesis and restenosis after angioplasty. PMID:11956327

  9. Time-dependent release of growth factors from implant surfaces treated with plasma rich in growth factors.

    PubMed

    Sánchez-Ilárduya, María Belén; Trouche, Elodie; Tejero, Ricardo; Orive, Gorka; Reviakine, Ilya; Anitua, Eduardo

    2013-05-01

    Plasma rich in growth factors (PRGFs) technology is an autologous platelet-rich plasma approach that provides a pool of growth factors and cytokines that have been shown to increase tissue regeneration and accelerate dental implant osseointegration. In this framework, the spatiotemporal release of growth factors and the establishment of a provisional fibrin matrix are likely to be key aspects governing the stimulation of the early phases of tissue regeneration around implants. We investigated the kinetics of growth factor release at implant surfaces functionalized either with PRGFs or platelet-poor plasma and correlated the results obtained with the morphology of the resulting interfaces. Our main finding is that activation and clot formation favors longer residence times of the growth factors at the interfaces studied, probably due to their retention in the adsorbed fibrin matrix. The concentration of the platelet-derived growth factors above the interfaces becomes negligible after 2-4 days and is significantly higher in the case of activated interfaces than in the case of nonactivated ones, whereas that of the plasmatic hepatocyte growth factor is independent of platelet concentration and activation, and remains significant for up to 9 days. Platelet-rich plasma preparations should be activated to permit growth factor release and thereby facilitate implant surface osseointegration.

  10. Oxidative inhibition of receptor-type protein-tyrosine phosphatase kappa by ultraviolet irradiation activates epidermal growth factor receptor in human keratinocytes.

    PubMed

    Xu, Yiru; Shao, Yuan; Voorhees, John J; Fisher, Gary J

    2006-09-15

    Ultraviolet (UV) irradiation rapidly increases tyrosine phosphorylation (i.e. activates) of epidermal growth factor receptors (EGFR) in human skin. EGFR-dependent signaling pathways drive increased expression of matrix metalloproteinases, whose actions fragment collagen and elastin fibers, the primary structural protein components in skin connective tissue. Connective tissue fragmentation, which results from chronic exposure to solar UV irradiation, is a major determinant of premature skin aging (photoaging). UV irradiation generates reactive oxygen species, which readily react with conserved cysteine residues in the active site of protein-tyrosine phosphatases (PTP). We report here that EGFR activation by UV irradiation results from oxidative inhibition of receptor type PTP-kappa (RPTP-kappa). RPTP-kappa directly counters intrinsic EGFR tyrosine kinase activity, thereby maintaining EGFR in an inactive state. Reversible, oxidative inactivation of RPTP-kappa activity by UV irradiation shifts the kinase-phosphatase balance in favor of EGFR activation. These data delineate a novel mechanism of EGFR regulation and identify RPTP-kappa as a key molecular target for antioxidant protection against skin aging.

  11. Enhanced antitumor activity of anti-epidermal growth factor receptor monoclonal antibody IMC-C225 in combination with irinotecan (CPT-11) against human colorectal tumor xenografts.

    PubMed

    Prewett, Marie C; Hooper, Andrea T; Bassi, Rajiv; Ellis, Lee M; Waksal, Harlan W; Hicklin, Daniel J

    2002-05-01

    Colon carcinomas frequently express the epidermal growth factor receptor (EGFR), and this expression correlates with more aggressive disease and poor prognosis. Previous studies have shown that EGFR blockade by monoclonal antibody IMC-C225 can inhibit the growth of human colon carcinoma tumor cells in vitro and xenografts of these tumors in athymic mice. In this report, we have studied the in vivo activity of IMC-C225 combined with the topoisomerase I inhibitor irinotecan (CPT-11) using two models of human colorectal carcinoma in nude mice. IMC-C225 was tested at a dose of 1 or 0.5 mg administered q3d. CPT-11 was administered at a dose of 100 mg/kg/week or a maximum tolerated dose of 150 mg/kg/week. Treatment with the combination of IMC-C225 (1 and 0.5 mg) and CPT-11 (100 mg/kg) significantly inhibited the growth of established DLD-1 and HT-29 tumors compared with either CPT-11 or IMC-C225 monotherapy (P < 0.05). Combination therapy with IMC-C225 (1 mg) and the MTD of CPT-11 (150 mg/kg) resulted in a regression rate of 100 and 60% of established DLD-1 and HT-29 tumors, respectively. In a refractory tumor model, combined treatment with IMC-C225 and CPT-11 significantly inhibited the growth of CPT-11 refractory DLD-1 and HT-29 tumors, whereas either agent alone did not control tumor growth. Histological examination of treated tumors showed extensive tumor necrosis, decreased tumor cell proliferation, increased tumor cell apoptosis, and a marked decrease in tumor vasculature. These results suggest that EGFR blockade by IMC-C225 combined with topoisomerase I inhibitors may be an effective therapy against chemorefractory colorectal carcinoma tumors.

  12. Inhibitors of Growth 1b Suppresses Peroxisome Proliferator-Activated Receptor-β/δ Expression Through Downregulation of Hypoxia-Inducible Factor 1α in Osteoblast Differentiation.

    PubMed

    Qu, Bo; Hong, Zhen; Gong, Kai; Sheng, Jun; Wu, Hong-Hua; Deng, Shao-Lin; Huang, Gang; Ma, Ze-Hui; Pan, Xian-Ming

    2016-04-01

    Bone formation, a highly regulated developmental process, involves osteoblast differentiation, which is controlled by different important transcription factors. Recent evidence has suggested possible negative regulation of inhibitors of growth (ING) 1b on the osteoblast marker expression. The aim of this study is to examine the detailed mechanism by which the activity of ING1b inhibits osteoblast differentiation. In the current study, we investigated the function and mechanism by which ING1b inhibits osteoblast differentiation using C3H10T1/2 mesenchymal stem cells and MC3T3-E1 preosteoblasts. Real-time polymerase chain reaction and Western blotting showed that ING1b was decreased during osteoblast differentiation and ING1b overexpression markedly decreased alkaline phosphatase (ALP) activity, runt-related transcription factor 2 (Runx2) expression, and collagen type 1 synthesis, whereas ING1b silencing significantly upregulated ALP activity, Runx2 expression, and collagen type 1 synthesis. Further studies indicated that ING1b suppressed the expression of peroxisome proliferator-activated receptor (PPAR)-β/δ in a hypoxia-inducible factor (HIF) 1α-dependent manner, while ING1b silencing significantly increased the expression of PPAR-β/δ and HIF1α. Moreover, PPAR-β/δ or HIF1α silencing significantly inhibited ALP activity, Runx2 expression, and collagen type 1 synthesis. These results demonstrated that ING1b is an important regulator of osteoblast differentiation and suppresses PPAR-β/δ. Our study may provide additional insight into osteoblast differentiation and offer a potential new molecular target for osteoporosis. PMID:26849833

  13. The immunomodulatory activity of human amniotic fluid can be correlated with transforming growth factor-beta 1 (TGF-beta 1) and beta 2 activity.

    PubMed Central

    Lang, A K; Searle, R F

    1994-01-01

    The role of alphafetoprotein (AFP) in the immunomodulatory activity of amniotic fluids (AF) from normally progressing human pregnancy (weeks 14-16) was investigated. A panel of 42 AF (25% v/v) reduced significantly phytohaemagglutinin (PHA)-induced peripheral blood mononuclear cell (PBMC) proliferation in serum-free cultures with a mean per cent inhibition of 68.4 +/- 5.5%. In contrast, AFP preparations, with one exception (U.AFP), failed to display inhibitory activity. Pretreatment of AF with anti-TGF-beta 1 and beta 2 antibodies used alone resulted in the mean per cent loss of inhibition of 33.1 +/- 3.9% and 52.3 +/- 7.5%, respectively. A summative loss of AF-mediated inhibition was detected when anti-TGF-beta 1 and beta 2 antibodies were used in combination, but immunomodulation was rarely abolished 100% by this treatment. Anti-TGF-beta 2 antibody treatment, unlike anti-TGF-beta 1 antibody treatment, reversed the inhibitory activity of U.AFP. The amount of TGF-beta 1 and beta 2 contained in human AF was studied by growth inhibition of Mv1 Lu cells. The mean levels of TGF-beta 1 and beta 2 in AF were 11 +/- 0.9 U/ml and 2.3 +/- 0.4 U/ml, respectively, which corresponds with a mean per cent inhibition of 49 +/- 4.7%. U.AFP also significantly inhibited Mv1 Lu cell growth. To investigate the mechanism of AF-mediated inhibition, the effect of AF and AFP on IL-2 production by concanavalin A (Con A)-stimulated PBMC blasts was determined by the CTLL-2 cell bioassay. IL-2 production was reduced 55.5% in AF-treated blasts and 61% in U.AFP-treated blasts compared with controls. Our findings indicate that the immunomodulatory activity of human AF can be correlated with TGF-beta 1 and beta 2 and not with AFP, the inhibitory activity of U.AFP preparation reflecting copurifying TGF-beta 2 activity. PMID:7518368

  14. Breast milk protects against the development of necrotizing enterocolitis through inhibition of Toll Like Receptor 4 in the intestinal epithelium via activation of the epidermal growth factor receptor

    PubMed Central

    Good, Misty; Sodhi, Chhinder P.; Egan, Charlotte E.; Afrazi, Amin; Jia, Hongpeng; Yamaguchi, Yukihiro; Lu, Peng; Branca, Maria F.; Ma, Congrong; Prindle, Thomas; Mielo, Samantha; Pompa, Anthony; Hodzic, Zerina; Ozolek, John A.; Hackam, David J.

    2015-01-01

    Breast milk is the most effective strategy to protect infants against necrotizing enterocolitis (NEC), a devastating disease which is characterized by severe intestinal necrosis. Previous studies have demonstrated that the lipopolysaccharide receptor toll-like receptor 4 (TLR4) plays a critical role in NEC development via deleterious effects on mucosal injury and repair. We now hypothesize that breast milk protects against NEC by inhibiting TLR4 within the intestinal epithelium, and sought to determine the mechanisms involved. Breast milk protected against NEC and reduced TLR4 signaling in wild-type neonatal mice, but not in mice lacking the epidermal growth factor receptor (EGFR), while selective removal of EGF from breast milk reduced its protective properties, indicating that breast milk inhibits NEC and attenuates TLR4 signaling via EGF/EGFR activation. Over-expression of TLR4 in the intestinal epithelium reversed the protective effects of breast milk. The protective effects of breast milk occurred via inhibition of enterocyte apoptosis and restoration of enterocyte proliferation. Importantly, in IEC-6 enterocytes, breast milk inhibited TLR4 signaling via inhibition of GSK3β. Taken together, these findings offer mechanistic insights into the protective role for breast milk in NEC, and support a link between growth factor and innate immune receptors in NEC pathogenesis. PMID:25899687

  15. Angiotensin II-induced pro-fibrotic effects require p38MAPK activity and transforming growth factor beta 1 expression in skeletal muscle cells.

    PubMed

    Morales, María Gabriela; Vazquez, Yaneisi; Acuña, María José; Rivera, Juan Carlos; Simon, Felipe; Salas, José Diego; Alvarez Ruf, Joel; Brandan, Enrique; Cabello-Verrugio, Claudio

    2012-11-01

    Fibrotic disorders are typically characterised by excessive connective tissue and extracellular matrix (ECM) deposition that preclude the normal healing of different tissues. Several skeletal muscle dystrophies are characterised by extensive fibrosis. Among the factors involved in skeletal muscle fibrosis is angiotensin II (Ang-II), a key protein of the renin-angiotensin system (RAS). We previously demonstrated that myoblasts responded to Ang-II by increasing the ECM protein levels mediated by AT-1 receptors, implicating an Ang-II-induced reactive oxygen species (ROS) by a NAD(P)H oxidase-dependent mechanism. In this paper, we show that in myoblasts, Ang-II induced the increase of transforming growth factor beta 1 (TGF-β1) and connective tissue growth factor (CTGF) expression through its AT-1 receptor. This effect is dependent of the NAD(P)H oxidase (NOX)-induced ROS, as indicated by a decrease of the expression of both pro-fibrotic factors when the ROS production was inhibited via the NOX inhibitor apocynin. The increase in pro-fibrotic factors levels was paralleled by enhanced p38MAPK and ERK1/2 phosphorylation in response to Ang-II. However, only the p38MAPK activity was critical for the Ang-II-induced fibrotic effects, as indicated by the decrease in the Ang-II-induced TGF-β1 and CTGF expression and fibronectin levels by SB-203580, an inhibitor of the p38MAPK, but not by U0126, an inhibitor of ERK1/2 phosphorylation. Furthermore, we showed that the Ang-II-dependent p38MAPK activation, but not the ERK1/2 phosphorylation, was necessary for the NOX-derived ROS. In addition, we demonstrated that TGF-β1 expression was required for the Ang-II-induced pro-fibrotic effects evaluated by using SB-431542, an inhibitor of TGF-βRI kinase activity, and by knocking down TGF-β1 levels by shRNA technique. These results strongly suggest that the fibrotic response to Ang-II is mediated by the AT-1 receptor and requires the p38MAPK phosphorylation, NOX-induced ROS, and TGF

  16. Transforming growth factor-beta1 induces activation of Ras, Raf-1, MEK and MAPK in rat hepatic stellate cells.

    PubMed

    Reimann, T; Hempel, U; Krautwald, S; Axmann, A; Scheibe, R; Seidel, D; Wenzel, K W

    1997-02-10

    The transdifferentiation of hepatic stellate cells into myofibroblast-like cells and the proliferation of the transdifferentiated cells are controlled by TGF-beta1. Little is known about the intracellular signal transducers of TGF-beta1. In this paper we show that in cultured hepatic stellate cells TGF-beta1 induces activation of Ras, Raf-1, MEK and MAPK p42 and p44. The activation of MAPK depends on the activation of MEK. Our data exclude that the observed effects are mediated by a bFGF or PDGF autocrine loop. PMID:9038360

  17. Role of LncRNA-activated by transforming growth factor beta in the progression of hepatitis C virus-related liver fibrosis.

    PubMed

    Fu, Na; Niu, Xuemin; Wang, Yang; Du, Huijuan; Wang, Baoyu; Du, Jinghua; Li, Ya; Wang, Rongqi; Zhang, Yuguo; Zhao, Suxian; Sun, Dianxing; Qiao, Liang; Nan, Yuemin

    2016-08-01

    Long non-coding RNA (LncRNA)-activated by transforming growth factor-beta (LncRNA-ATB) is a key regulator of transforming growth factor-beta (TGF-β) signaling pathway, and is positively correlated with the development of liver cirrhosis and vascular invasion of hepatocellular carcinoma (HCC). However, the role of LncRNA-ATB in hepatitis C virus (HCV)-related liver fibrosis remains largely unknown. In the present study, we confirmed a high expression level of LncRNA-ATB in the liver tissues and plasma samples of patients with HCV-related hepatic fibrosis, and the plasma level of LncRNA-ATB was significantly correlated with liver fibrosis stages. Furthermore, increased expression level of LncRNA-ATB was also present in activated hepatic stellate cells (HSCs), and knockdown of LncRNA-ATB inhibited the expression of alpha-smooth muscle actin (α-SMA) and alpha-1 type I collagen (Col1A1). LncRNA-ATB was found to share the common miRNA responsive element of miR-425-5p with TGF-β type II receptor (TGF-βRII) and SMAD2. Ectopic expression of LncRNA-ATB in HSCs could upregulate the protein expression of TGF-βRII and SMAD2 by inhibiting the endogenous miR-425-5p. Moreover, overexpression of miR-425-5p could partly abrogate the expression of TGF-βRII and SMAD2 induced by LncRNA-ATB. Hence, we conclude that LncRNA-ATB promotes HCV-induced liver fibrogenesis by activating HSCs and increasing collagen I production through competitively binding to miR-425-5p. LncRNA-ATB may be a novel diagnostic biomarker and a potential therapeutic target for HCV-related hepatic fibrosis. PMID:27585228

  18. Basic fibroblast growth factor promotes melanocyte migration via activating PI3K/Akt-Rac1-FAK-JNK and ERK signaling pathways.

    PubMed

    Shi, Hongxue; Lin, Beibei; Huang, Yan; Wu, Jiang; Zhang, Hongyu; Lin, Cai; Wang, Zhouguang; Zhu, Jingjing; Zhao, Yingzhen; Fu, Xiaobing; Lou, Zhencai; Li, Xiaokun; Xiao, Jian

    2016-09-01

    Vitiligo is a depigmentation disorder characterized by loss of functional melanocytes of the skin epidermis. The pathogenesis of vitiligo remains elusive. The purpose of this study is to investigate the effects of basic fibroblast growth factor (bFGF) on melanocyte migration, including its biochemical mechanism using transwell assay in vitro. We found that melanocyte treated with bFGF showed a significant increase in migration and cytoskeletal rearrangement. These changes were associated with increased activation of PI3K/Akt, Rac1, FAK, JNK, and ERK. Likewise, reduction of PI3K/Akt, Rac1, FAK, JNK, and ERK activity using selective inhibitors or siRNA was associated with impediment of bFGF-induced melanocyte migration. In addition, activity of Rac1, FAK, and JNK was reduced in cells in which PI3K/Akt was inhibited, activity of FAK and JNK was reduced in cells in which the Rac1 was inhibited, and activity of JNK was reduced in cells in which the FAK was inhibited. Collectively, these data demonstrate that bFGF facilitated melanocyte migration via PI3K/Akt-Rac1-FAK-JNK and ERK signaling pathways. © 2016 IUBMB Life, 68(9):735-747, 2016. PMID:27350596

  19. Graphene Nanoribbons Elicit Cell Specific Uptake and Delivery Via Activation of Epidermal Growth Factor Receptor Enhanced by Human PapillomaVirus E5 Protein

    PubMed Central

    Chowdhury, Sayan Mullick; Mannepalli, Prady; Sitharaman, Balaji

    2014-01-01

    Ligands such as peptides, antibodies or other epitopes bind and activate specific cell receptors, and are employed for targeted cellular delivery of pharmaceuticals such as drugs, genes and imaging agents. Herein, we show that oxidized graphene nanoribbons, non-covalently functionalized with PEG-DSPE (1, 2-distearoyl-sn-glycero-3-phosphoethanolamine-N[amino(polyethyleneglycol)]) (O-GNR-PEG-DSPE) activate epidermal growth factor receptors (EGFRs). This activation generates predominantly dynamin-dependent macropinocytosis-like response, and results in significant O-GNR-PEG-DSPE uptake into cells with high EGFR expression. Cells with an integrated human papillomavirus (HPV) genome also show increased uptake due to the modulation of the activated EFGR by the viral protein E5. We demonstrate that this cell specific uptake of O-GNR-PEG-DSPE can be exploited to achieve significantly enhanced drug efficacies even in drug resistant cells. These results have implications towards the development of active targeting and delivery agents without ligand functionalization for use in the diagnosis and treatment of pathologies that overexpress EGFR or mediated by HPV. PMID:24980059

  20. 3BP-1, an SH3 domain binding protein, has GAP activity for Rac and inhibits growth factor-induced membrane ruffling in fibroblasts.

    PubMed Central

    Cicchetti, P; Ridley, A J; Zheng, Y; Cerione, R A; Baltimore, D

    1995-01-01

    The SH3 binding protein, 3BP-1, was originally cloned as a partial cDNA from an expression library using the Abl SH3 domain as a probe. In addition to an SH3 binding domain, 3BP-1 displayed homology to a class of GTPase activating proteins (GAPs) active against Rac and Rho proteins. We report here a full length cDNA of 3BP-1 which extends the homology to GAP proteins previously noted. 3BP-1 functions in vitro as a GAP with a specificity for Rac-related G proteins. Microinjection of the 3BP-1 protein into serum-starved fibroblasts produces an inhibition of platelet-derived growth factor (PDGF)-induced membrane ruffling mediated by Rac. Co-injection of 3BP-1 with an activated Rac mutant that is unresponsive to GAPs, counter-acts this inhibition. 3BP-1 does not show in vitro activity towards Rho and, in agreement with this finding, microinjection of 3BP-1 into fibroblasts has no effect on lysophosphatidic acid (LPA)-induced stress fiber assembly mediated by Rho. Thus 3BP-1 is a new and specific Rac GAP that can act in cells to counter Rac-mediated membrane ruffling. How its SH3 binding site interacts with its GAP activity remains to be understood. Images PMID:7621827

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

    EPA Science Inventory

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

  2. E3B1, a human homologue of the mouse gene product Abi-1, sensitizes activation of Rap1 in response to epidermal growth factor

    SciTech Connect

    Jenei, Veronika; Andersson, Tommy; Jakus, Judit; Dib, Karim . E-mail: k.dib@qub.ac.uk

    2005-11-01

    E3B1, a human homologue of the mouse gene product Abi-1, has been implicated in growth-factor-mediated regulation of the small GTPases p21{sup Ras} and Rac. E3b1 is a regulator of Rac because it can form a complex with Sos-1 and eps8, and such a Sos-1-e3B1-eps8 complex serves as a guanine nucleotide exchange factor for Rac. In the present study, we found that overexpression of e3B1 in NIH3T3/EGFR cells sensitized EGF-induced activation of Rac1, whereas it had no impact on EGF-induced activation of p21{sup Ras}. Remarkably, we found that EGF-induced activation of the p21{sup Ras}-related GTPase Rap1 was also sensitized in NIH3T3/EGFR-e3B1 cells. Thus, in NIH3T3/EGFR-e3B1 cells, maximal EGF-induced activation of Rap1 occurs with a dose of EGF much lower than in NIH3T3/EGFR cells. We also report that overexpression of e3B1 in NIH3T3/EGFR cells renders EGF-induced activation of Rap1 completely dependent on Src tyrosine kinases but not on c-Abl. However, EGF-induced tyrosine phosphorylation of the Rap GEF C3G occurred regardless of whether e3B1 was overexpressed or not, and this did not involve Src tyrosine kinases. Accordingly, we propose that overexpression of e3B1 in NIH3T3/EGFR cells leads to mobilization of Src tyrosine kinases that participate in EGF-induced activation of Rap1 and inhibition of cell proliferation.

  3. P-REX1 creates a positive feedback loop to activate growth factor receptor, PI3K/AKT, and MEK/ERK signaling in breast cancer

    PubMed Central

    Dillon, Lloye M.; Bean, Jennifer R.; Yang, Wei; Shee, Kevin; Symonds, Lynn K.; Balko, Justin M.; McDonald, W. Hayes; Liu, Shuying; Gonzalez-Angulo, Ana M.; Mills, Gordon B.; Arteaga, Carlos L.; Miller, Todd W.

    2014-01-01

    Phosphatidylinositol 3-kinase (PI3K) promotes cancer cell survival, migration, growth, and proliferation by generating phosphatidylinositol 3,4,5-trisphosphate (PIP3) in the inner leaflet of the plasma membrane. PIP3 recruits pleckstrin homology (PH) domain-containing proteins to the membrane to activate oncogenic signaling cascades. Anti-cancer therapeutics targeting the PI3K/AKT/mTOR pathway are in clinical development. In a mass spectrometric screen to identify PIP3-regulated proteins in breast cancer cells, levels of the Rac activator PIP3-dependent Rac exchange factor 1 (P-REX1) increased in response to PI3K inhibition, and decreased upon loss of the PI3K antagonist PTEN. P-REX1 mRNA and protein levels were positively correlated with ER expression, and inversely correlated with PI3K pathway activation in breast tumors as assessed by gene expression and phosphoproteomic analyses. P-REX1 increased activation of Rac1, PI3K/AKT, and MEK/ERK signaling in a PTEN-independent manner, and promoted cell and tumor viability. Loss of P-REX1 or inhibition of Rac suppressed PI3K/AKT and MEK/ERK, and decreased viability. P-REX1 also promoted insulin-like growth factor-1 receptor (IGF-1R) activation, suggesting that P-REX1 provides positive feedback to activators upstream of PI3K. In support of a model where PIP3-driven P-REX1 promotes both PI3K/AKT and MEK/ERK signaling, high levels of P-REX1 mRNA (but not phospho-AKT or a transcriptomic signature of PI3K activation) were predictive of sensitivity to PI3K inhibitors among breast cancer cell lines. P-REX1 expression was highest in ER+ breast tumors compared to many other cancer subtypes, suggesting that neutralizing the P-REX1/Rac axis may provide a novel therapeutic approach to selectively abrogate oncogenic signaling in breast cancer cells. PMID:25284585

  4. Transforming Growth Factor-β-Activated Kinase 1 Is Required for Human FcγRIIIb-Induced Neutrophil Extracellular Trap Formation.

    PubMed

    Alemán, Omar Rafael; Mora, Nancy; Cortes-Vieyra, Ricarda; Uribe-Querol, Eileen; Rosales, Carlos

    2016-01-01

    Neutrophils (PMNs) are the most abundant leukocytes in the blood. PMN migrates from the circulation to sites of infection where they are responsible for antimicrobial functions. PMN uses phagocytosis, degranulation, and formation of neutrophil extracellular traps (NETs) to kill microbes. Several stimuli, including bacteria, fungi, and parasites, and some pharmacological compounds, such as Phorbol 12-myristate 13-acetate (PMA), are efficient inducers of NETs. Antigen-antibody complexes are also capable of inducing NET formation. Recently, it was reported that FcγRIIIb cross-linking induced NET formation similarly to PMA stimulation. Direct cross-linking of FcγRIIA or integrins did not promote NET formation. FcγRIIIb-induced NET formation presented different kinetics from PMA-induced NET formation, suggesting differences in signaling. Because FcγRIIIb also induces a strong activation of extracellular signal-regulated kinase (ERK) and nuclear factor Elk-1, and the transforming growth factor-β-activated kinase 1 (TAK1) has recently been implicated in ERK signaling, in the present report, we explored the role of TAK1 in the signaling pathway activated by FcγRIIIb leading to NET formation. FcγRIIIb was stimulated by specific monoclonal antibodies, and NET formation was evaluated in the presence or absence of pharmacological inhibitors. The antibiotic LL Z1640-2, a selective inhibitor of TAK1 prevented FcγRIIIb-induced, but not PMA-induced NET formation. Both PMA and FcγRIIIb cross-linking induced phosphorylation of ERK. But, LL Z1640-2 only inhibited the FcγRIIIb-mediated activation of ERK. Also, only FcγRIIIb, similarly to transforming growth factor-β-induced TAK1 phosphorylation. A MEK (ERK kinase)-specific inhibitor was able to prevent ERK phosphorylation induced by both PMA and FcγRIIIb. These data show for the first time that FcγRIIIb cross-linking activates TAK1, and that this kinase is required for triggering the MEK/ERK signaling pathway to NETosis

  5. Transforming Growth Factor-β-Activated Kinase 1 Is Required for Human FcγRIIIb-Induced Neutrophil Extracellular Trap Formation

    PubMed Central

    Alemán, Omar Rafael; Mora, Nancy; Cortes-Vieyra, Ricarda; Uribe-Querol, Eileen; Rosales, Carlos

    2016-01-01

    Neutrophils (PMNs) are the most abundant leukocytes in the blood. PMN migrates from the circulation to sites of infection where they are responsible for antimicrobial functions. PMN uses phagocytosis, degranulation, and formation of neutrophil extracellular traps (NETs) to kill microbes. Several stimuli, including bacteria, fungi, and parasites, and some pharmacological compounds, such as Phorbol 12-myristate 13-acetate (PMA), are efficient inducers of NETs. Antigen–antibody complexes are also capable of inducing NET formation. Recently, it was reported that FcγRIIIb cross-linking induced NET formation similarly to PMA stimulation. Direct cross-linking of FcγRIIA or integrins did not promote NET formation. FcγRIIIb-induced NET formation presented different kinetics from PMA-induced NET formation, suggesting differences in signaling. Because FcγRIIIb also induces a strong activation of extracellular signal-regulated kinase (ERK) and nuclear factor Elk-1, and the transforming growth factor-β-activated kinase 1 (TAK1) has recently been implicated in ERK signaling, in the present report, we explored the role of TAK1 in the signaling pathway activated by FcγRIIIb leading to NET formation. FcγRIIIb was stimulated by specific monoclonal antibodies, and NET formation was evaluated in the presence or absence of pharmacological inhibitors. The antibiotic LL Z1640-2, a selective inhibitor of TAK1 prevented FcγRIIIb-induced, but not PMA-induced NET formation. Both PMA and FcγRIIIb cross-linking induced phosphorylation of ERK. But, LL Z1640-2 only inhibited the FcγRIIIb-mediated activation of ERK. Also, only FcγRIIIb, similarly to transforming growth factor-β-induced TAK1 phosphorylation. A MEK (ERK kinase)-specific inhibitor was able to prevent ERK phosphorylation induced by both PMA and FcγRIIIb. These data show for the first time that FcγRIIIb cross-linking activates TAK1, and that this kinase is required for triggering the MEK/ERK signaling pathway to

  6. Improved biological activity of a single chain antibody fragment against human epidermal growth factor receptor 2 (HER2) expressed in the periplasm of Escherichia coli.

    PubMed

    Akbari, Vajihe; Sadeghi, Hamid Mir Mohammad; Jafarian-Dehkordi, Abbas; Abedi, Daryoush; Chou, C Perry

    2015-12-01

    A novel monoclonal antibody against human epidermal growth factor receptor 2 (HER2), i.e., pertuzumab (Perjeta®) developed by Genentech, has been verified to be effective in treating metastatic HER2-overexpressing breast cancer. The fact that the presence of the Fc region of the anti-HER2 is uncritical for growth inhibition of tumor cells suggests the potential biological activity of the associated antibody fragments. In the present study, we report functional expression of anti-HER2his-scFv, a single-chain variable fragment (scFv) derived from pertuzumab, in the periplasm of Escherichia coli and its purification. Biological activity of the soluble scFv produced in this manner was characterized using immunofluorescent staining, immunocytochemistry, flow cytometry and cytotoxicity assay. The effect of anti-HER2his-scFv on HER2 dimerization was also assessed by tyrosine kinase assay. It was observed that the purified scFv had a high specificity and affinity to HER2 receptors expressed on the surface of tumor cells with a selective cytotoxic effect on HER2-overexpressing SK-OV-3 cells. In addition, anti-HER2his-scFv was able to suppress phosphorylation of HER2 in the presence of heregulin. The results suggest that anti-HER2his-scFv can be a potential candidate for various therapeutic and diagnosis applications.

  7. [Growth factors in proliferative diabetic retinopathy].

    PubMed

    Ioniţă, M

    1997-01-01

    This work presents the possible implications of the angiogenic growth factors and some cell mediators in the initiation and development of the neovascular proliferation in diabetic retinopathy. According to the physiopathologic theories stated above, that are implied in the generation of proliferative diabetic retinopathy, here are some therapeutic experiments based on the action of the angiogenic growth factors. PMID:9409959

  8. Vitamin D binding protein-macrophage activating factor (DBP-maf) inhibits angiogenesis and tumor growth in mice.

    PubMed

    Kisker, Oliver; Onizuka, Shinya; Becker, Christian M; Fannon, Michael; Flynn, Evelyn; D'Amato, Robert; Zetter, Bruce; Folkman, Judah; Ray, Rahul; Swamy, Narasimha; Pirie-Shepherd, Steven

    2003-01-01

    We have isolated a selectively deglycosylated form of vitamin D binding protein (DBP-maf) generated from systemically available DBP by a human pancreatic cancer cell line. DBP-maf is antiproliferative for endothelial cells and antiangiogenic in the chorioallantoic membrane assay. DBP-maf administered daily was able to potently inhibit the growth of human pancreatic cancer in immune compromised mice (T/C=0.09). At higher doses, DBP-maf caused tumor regression. Histological examination revealed that treated tumors had a higher number of infiltrating macrophages as well as reduced microvessel density, and increased levels of apoptosis relative to untreated tumors. Taken together, these data suggest that DBP-maf is an antiangiogenic molecule that can act directly on endothelium as well as stimulate macrophages to attack both the endothelial and tumor cell compartment of a growing malignancy. PMID:12659668

  9. Vitamin D Binding Protein-Macrophage Activating Factor (DBP-maf) Inhibits Angiogenesis and Tumor Growth in Mice1

    PubMed Central

    Kisker, Oliver; Onizuka, Shinya; Becker, Christian M; Fannon, Michael; Flynn, Evelyn; D'Amato, Robert; Zetter, Bruce; Folkman, Judah; Ray, Rahul; Swamy, Narasimha; Pirie-Shepherd, Steven

    2003-01-01

    Abstract We have isolated a selectively deglycosylated form of vitamin D binding protein (DBP-maf) generated from systemically available DBP by a human pancreatic cancer cell line. DBP-maf is antiproliferative for endothelial cells and antiangiogenic in the chorioallantoic membrane assay. DBP-maf administered daily was able to potently inhibit the growth of human pancreatic cancer in immune compromised mice (T/C=0.09). At higher doses, DBP-maf caused tumor regression. Histological examination revealed that treated tumors had a higher number of infiltrating macrophages as well as reduced microvessel density, and increased levels of apoptosis relative to untreated tumors. Taken together, these data suggest that DBP-maf is an antiangiogenic molecule that can act directly on endothelium as well as stimulate macrophages to attack both the endothelial and tumor cell compartment of a growing malignancy. PMID:12659668

  10. A composite demineralized bone matrix--self assembling peptide scaffold for enhancing cell and growth factor activity in bone marrow.

    PubMed

    Hou, Tianyong; Li, Zhiqiang; Luo, Fei; Xie, Zhao; Wu, Xuehui; Xing, Junchao; Dong, Shiwu; Xu, Jianzhong

    2014-07-01

    The need for suitable bone grafts is high; however, there are limitations to all current graft sources, such as limited availability, the invasive harvest procedure, insufficient osteoinductive properties, poor biocompatibility, ethical problems, and degradation properties. The lack of osteoinductive properties is a common problem. As an allogenic bone graft, demineralized bone matrix (DBM) can overcome issues such as limited sources and comorbidities caused by invasive harvest; however, DBM is not sufficiently osteoinductive. Bone marrow has been known to magnify osteoinductive components for bone reconstruction because it contains osteogenic cells and factors. Mesenchymal stem cells (MSCs) derived from bone marrow are the gold standard for cell seeding in tissue-engineered biomaterials for bone repair, and these cells have demonstrated beneficial effects. However, the associated high cost and the complicated procedures limit the use of tissue-engineered bone constructs. To easily enrich more osteogenic cells and factors to DBM by selective cell retention technology, DBM is modified by a nanoscale self-assembling peptide (SAP) to form a composite DBM/SAP scaffold. By decreasing the pore size and increasing the charge interaction, DBM/SAP scaffolds possess a much higher enriching yield for osteogenic cells and factors compared with DBM alone scaffolds. At the same time, SAP can build a cellular microenvironment for cell adhesion, proliferation, and differentiation that promotes bone reconstruction. As a result, a suitable bone graft fabricated by DBM/SAP scaffolds and bone marrow represents a new strategy and product for bone transplantation in the clinic.

  11. Role of transiently altered sarcolemmal membrane permeability and basic fibroblast growth factor release in the hypertrophic response of adult rat ventricular myocytes to increased mechanical activity in vitro.

    PubMed Central

    Kaye, D; Pimental, D; Prasad, S; Mäki, T; Berger, H J; McNeil, P L; Smith, T W; Kelly, R A

    1996-01-01

    One of the trophic factors that has been implicated in initiating or facilitating growth in response to increased mechanical stress in several tissues and cell types is basic fibroblast growth factor (bFGF; FGF-2). Although mammalian cardiac muscle cells express bFGF, it is not known whether it plays a role in mediating cardiac adaptation to increased load, nor how release of the cytosolic 18-kD isoform of bFGF would be regulated in response to increased mechanical stress. To test the hypothesis that increased mechanical activity induces transient alterations in sarcolemmal permeability that allow cytosolic bFGF to be released and subsequently to act as an autocrine and paracrine growth stimulus, we examined primary isolates of adult rat ventricular myocytes maintained in serum-free, defined medium that were continually paced at 3 Hz for up to 5 d. Paced myocytes, but not nonpaced control cells, exhibited a "hypertrophic" response, which was characterized by increases in the rate of phenylalanine incorporation, total cellular protein content, and cell size. These changes could be mimicked in control cells by exogenous recombinant bFGF and could be blocked in continually paced cells by a specific neutralizing anti-bFGF antibody. In addition, medium conditioned by continually paced myocytes contained significantly more bFGF measured by ELISA and more mitogenic activity for 3T3 cells, activity that could be reduced by a neutralizing anti-bFGF antibody. The hypothesis that transient membrane disruptions sufficient to allow release of cytosolic bFGF occur in paced myocytes was examined by monitoring the rate of uptake into myocytes from the medium of 10-kD dextran linked to fluorescein. Paced myocytes exhibited a significantly higher rate of fluoresceinlabeled dextran uptake. These data are consistent with the hypothesis that nonlethal, transient alterations in sarcolemmal membrane permeability with release of cytosolic bFGF is one mechanism by which increased

  12. Mitogenic hormone-induced intracellular message: assay and partial characterization of an activator of DNA replication induced by epidermal growth factor.

    PubMed Central

    Das, M

    1980-01-01

    This paper explores the pathway from nuclear quiescence to mitogenesis. It describes an in vitro assay for an activator of DNA replication induced by epidermal growth factor (EGF) in responsive cells. Cytoplasmic extracts from EGF-treated 3T3 cells were found to contain substances that can stimulate DNA synthesis in isolated nuclei from spleen cells of adult frogs. Extracts from untreated resting 3T3 cells lack this activity, and EGF itself is incapable of stimulating DNA synthesis in these cell-free systems. The extract-induced stimulation of incorporation of [3H]dTTP into nuclear DNA is ATP dependent and requires the presence of the four deoxyribonucleoside triphosphates, suggesting the occurrence of replication rather than repair synthesis. This cell-free assay has been used to obtain some initial insights into the mechanism of induction and biochemical characterization of the intermediate in EGF action. Half-maximal induction of the active intracellular substance is achieved at about 0.08 nM EGF, a concentration that correlates well with the concentration required for half-maximal mitogenesis. Studies on the biochemical characteristics of this active substance strongly suggest that the activity is associated with a protein. The activity is nondialyzable and sensitive to trypsin and heat. Sucrose gradient centrifugation of the extract revealed three peaks of activity with molecular weights of 46,000, 110,000, and 270,000 (sedimentation coefficients: 3.7 S, 6.6 S, and 12 S, respectively). These results indicate that receptor-EGF interaction at the cell surface leads to the intracellular generation of protein that are capable of stimulating quiescent nuclei into activity. PMID:6965791

  13. Activation of epidermal growth factor receptor mediates mucin production stimulated by p40, a Lactobacillus rhamnosus GG-derived protein.

    PubMed

    Wang, Lihong; Cao, Hailong; Liu, Liping; Wang, Bangmao; Walker, W Allan; Acra, Sari A; Yan, Fang

    2014-07-18

    The mucus layer coating the gastrointestinal tract serves as the first line of intestinal defense against infection and injury. Probiotics promote mucin production by goblet cells in the intestine. p40, a Lactobacillus rhamnosus GG-derived soluble protein, has been shown to transactivate the EGF receptor (EGFR) in intestinal epithelial cells, which is required for inhibition of apoptosis and preservation of barrier function in the colon, thereby ameliorating intestinal injury and colitis. Because activation of EGFR has been shown to up-regulate mucin production in goblet cells, the purpose of this study was to investigate the effects and mechanisms of p40 regulation of mucin production. p40 activated EGFR and its downstream target, Akt, in a concentration-dependent manner in LS174T cells. p40 stimulated Muc2 gene expression and mucin production in LS174T cells, which were abolished by inhibition of EGFR kinase activity, down-regulation of EGFR expression by EGFR siRNA transfection, or suppression of Akt activation. Treatment with p40 increased mucin production in the colonic epithelium, thus thickening the mucus layer in the colon of wild type, but not of Egfr(wa5) mice, which have a dominant negative mutation in the EGFR kinase domain. Furthermore, inhibition of mucin-type O-linked glycosylation suppressed the effect of p40 on increasing mucin production and protecting intestinal epithelial cells from TNF-induced apoptosis in colon organ culture. Thus, these results suggest that p40-stimulated activation of EGFR mediates up-regulation of mucin production, which may contribute to the mechanisms by which p40 protects the intestinal epithelium from injury.

  14. CCAAT/enhancer-binding protein delta activates insulin-like growth factor-I gene transcription in osteoblasts. Identification of a novel cyclic AMP signaling pathway in bone

    NASA Technical Reports Server (NTRS)

    Umayahara, Y.; Ji, C.; Centrella, M.; Rotwein, P.; McCarthy, T. L.

    1997-01-01

    Insulin-like growth factor-I (IGF-I) plays a key role in skeletal growth by stimulating bone cell replication and differentiation. We previously showed that prostaglandin E2 (PGE2) and other cAMP-activating agents enhanced IGF-I gene transcription in cultured primary rat osteoblasts through promoter 1, the major IGF-I promoter, and identified a short segment of the promoter, termed HS3D, that was essential for hormonal regulation of IGF-I gene expression. We now demonstrate that CCAAT/enhancer-binding protein (C/EBP) delta is a major component of a PGE2-stimulated DNA-protein complex involving HS3D and find that C/EBPdelta transactivates IGF-I promoter 1 through this site. Competition gel shift studies first indicated that a core C/EBP half-site (GCAAT) was required for binding of a labeled HS3D oligomer to osteoblast nuclear proteins. Southwestern blotting and UV-cross-linking studies showed that the HS3D probe recognized a approximately 35-kDa nuclear protein, and antibody supershift assays indicated that C/EBPdelta comprised most of the PGE2-activated gel-shifted complex. C/EBPdelta was detected by Western immunoblotting in osteoblast nuclear extracts after treatment of cells with PGE2. An HS3D oligonucleotide competed effectively with a high affinity C/EBP site from the rat albumin gene for binding to osteoblast nuclear proteins. Co-transfection of osteoblast cell cultures with a C/EBPdelta expression plasmid enhanced basal and PGE2-activated IGF-I promoter 1-luciferase activity but did not stimulate a reporter gene lacking an HS3D site. By contrast, an expression plasmid for the related protein, C/EBPbeta, did not alter basal IGF-I gene activity but did increase the response to PGE2. In osteoblasts and in COS-7 cells, C/EBPdelta, but not C/EBPbeta, transactivated a reporter gene containing four tandem copies of HS3D fused to a minimal promoter; neither transcription factor stimulated a gene with four copies of an HS3D mutant that was unable to bind osteoblast

  15. Epidermal growth factor upregulates motility of Mat-LyLu rat prostate cancer cells partially via voltage-gated Na+ channel activity

    PubMed Central

    Ding, Yanning; Brackenbury, William J.; Onganer, Pinar U.; Montano, Ximena; Porter, Louise M.; Bates, Lucy F.; Djamgoz, Mustafa B. A.

    2014-01-01

    The main aim of this investigation was to determine whether a functional relationship existed between epidermal growth factor (EGF) and voltage-gated sodium channel (VGSC) upregulation, both associated with strongly metastatic prostate cancer cells. Incubation with EGF for 24 h more than doubled VGSC current density. Similar treatment with EGF significantly and dose-dependently enhanced the cells’ migration through Transwell filters. Both the patch clamp recordings and the migration assay suggested that endogenous EGF played a similar role. Importantly, co-application of EGF and tetrodotoxin, a highly selective VGSC blocker, abolished 65% of the potentiating effect of EGF. It is suggested that a significant portion of the EGF-induced enhancement of migration occurred via VGSC activity. PMID:17960590

  16. The matrix-binding domain of microfibril-associated glycoprotein-1 targets active connective tissue growth factor to a fibroblast-produced extracellular matrix.

    PubMed

    Weinbaum, Justin S; Tranquillo, Robert T; Mecham, Robert P

    2010-11-10

    It is advantageous to use biomaterials in tissue engineering that stimulate extracellular matrix (ECM) production by the cellular component. Connective tissue growth factor (CTGF) stimulates type I collagen (COL1A1) transcription, but is functionally limited as a free molecule. Using a matrix-binding domain (MBD) from microfibril-associated glycoprotein-1, the fusion protein MBD-CTGF was targeted to the ECM and tested for COL1A1 transcriptional activation. MBD-CTGF produced by the ECM-synthesizing fibroblasts, or provided exogenously, localized to the elastic fiber ECM. MBD-CTGF, but not CTGF alone, led to a two-fold enhancement of COL1A1 expression. This study introduces a targeting technology that can be used to elevate collagen transcription in engineered tissues and thereby improve tissue mechanics.

  17. Discovery and Evaluation of Clinical Candidate AZD3759, a Potent, Oral Active, Central Nervous System-Penetrant, Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor.

    PubMed

    Zeng, Qingbei; Wang, Jiabing; Cheng, Ziqiang; Chen, Kan; Johnström, Peter; Varnäs, Katarina; Li, David Yunzhi; Yang, Zhen Fan; Zhang, Xiaolin

    2015-10-22

    Recent reports suggest that an increasing number of patients with lung cancer, especially those with activating mutations of the epidermal growth factor receptor (EGFR), also present with brain metastases and leptomeningeal metastases. These patients have poor prognosis as there are no approved drugs for these indications. Available agents have poor efficacy for these patients even at well above their standard dose. Herein, we report the discovery of (4-[(3-chloro-2-fluorophenyl)amino]-7-methoxyquinazolin-6-yl (2R)-2,4-dimethylpiperazine-1-carboxylate 1m (AZD3759), an investigational drug currently in Phase 1 clinical trial, which has excellent central nervous system penetration and which induces profound regression of brain metastases in a mouse model. PMID:26313252

  18. Histone Deacetylase Inhibitors Enhance the Apoptotic Activity of Insulin-Like Growth Factor Binding Protein-3 by Blocking PKC-Induced IGFBP-3 Degradation

    PubMed Central

    Oh, Seung Hyun; Whang, Young Mi; Min, Hye-Young; Han, Seung Ho; Kang, Ju-Hee; Song, Ki-Hoon; Glisson, Bonnie S.; Kim, Yeul Hong; Lee, Ho-Young

    2012-01-01

    Overexpression of insulin-like growth factor binding protein (IGFBP)-3 induces apoptosis of cancer cells. However, preexisting resistance to IGFBP-3 could limit its antitumor activities. This study characterizes the efficacy and mechanism of the combination of recombinant IGFBP-3 (rIGFBP-3) and HDAC inhibitors to overcome IGFBP-3 resistance in a subset of non-small cell lung cancer (NSCLC) and head and neck squamous cell carcinoma (HNSCC) cells. The effects of the combination of rIGFBP-3 and a number of HDAC inhibitors on cell proliferation and apoptosis were assessed in vitro and in vivo by using the MTT assay, a flow cytometry-based TUNEL assay, western blot analyses, and the NSCLC xenograft tumor model. Combined treatment with HDAC inhibitors and rIGFBP-3 had synergistic antiproliferative effects accompanied by increased apoptosis rates in a subset of NSCLC and HNSCC cell lines in vitro. Moreover, combined treatment with depsipeptide and rIGFBP-3 completely suppressed tumor growth and increased the apoptosis rate in vivo in H1299 NSCLC xenografts. Evidence suggests that HDAC inhibitors increased the half-life of rIGFBP-3 protein by blocking protein kinase C (PKC)-mediated phosphorylation and degradation of rIGFBP-3. In addition, combined treatment of IGFBP-3 with an HDAC inhibitor facilitates apoptosis through up-regulation of rIGFBP-3 stability and Akt signaling inhibition. The ability of HDAC inhibitors to decrease PKC activation may enhance apoptotic activities of rIGFBP-3 in NSCLC cells in vitro and in vivo. These results indicated that combined treatment with HDAC inhibitor and rIGFBP-3 could be an effective treatment strategy for NSCLC and HNSCC with highly activated PKC. PMID:22362554

  19. Suppressing Akt phosphorylation and activating Fas by safrole oxide inhibited angiogenesis and induced vascular endothelial cell apoptosis in the presence of fibroblast growth factor-2 and serum.

    PubMed

    Zhao, Jing; Miao, Junying; Zhao, Baoxiang; Zhang, Shangli; Yin, Deling

    2006-01-01

    At present, vascular endothelial cell (VEC) apoptosis induced by deprivation of fibroblast growth factor-2 (FGF-2) and serum has been well studied. But how to trigger VEC apoptosis in the presence of FGF-2 and serum is not well known. To address this question, in this study, the effects of safrole oxide on angiogenesis and VEC growth stimulated by FGF-2 were investigated. The results showed that safrole oxide inhibited angiogenesis and induced VEC apoptosis in the presence of FGF-2 and serum. To understand the possible mechanism of safrole oxide acting, we first examined the phosphorylation of Akt and the activity of nitric oxide synthase (NOS); secondly, we analyzed the expressions and distributions of Fas and P53; then we measured the activity of phosphatidylcholine specific phospholipase C (PC-PLC) in the VECs treated with and without safrole oxide. The results showed that this small molecule obviously suppressed Akt phosphorylation and the activity of NOS, and promoted the expressions of Fas and P53 markedly. Simultaneously, Fas protein clumped on cell membrane, instead of homogenously distributed. The activity of PC-PLC was not changed obviously. The data suggested that safrole oxide effectively inhibited angiogenesis and triggered VEC apoptosis in the presence of FGF-2 and serum, and it might perform its functions by suppressing Akt/NOS signal pathway, upregulating the expressions of Fas and P53 and modifying the distributing pattern of Fas in VEC. This finding provided a powerful chemical probe for promoting VEC apoptosis during angiogenesis stimulated by FGF-2.

  20. Effects of Comb Tooth Cap Medicinal Mushroom, Hericium ramosum (Higher Basidiomycetes) Mycelia on DPPH Radical Scavenging Activity and Nerve Growth Factor Synthesis.

    PubMed

    Suruga, Kohei; Kadokura, Kazunari; Sekino, Yoshihiro; Nakano, Takafumi; Matsuo, Koichi; Irie, Keiichi; Mishima, Kenichi; Yoneyama, Makoto; Komatsu, Yasuhiro

    2015-01-01

    The goal of this study was to evaluate the antioxidant effects of and nerve growth factor (NGF) synthesis caused by Hericium ramosum mycelia. Wild mushroom fruiting bodies were collected from nature to isolate their mycelia. Pieces of H. ramosum fruiting bodies were plated onto 90-mm Petri dishes with potato dextrose agar medium to isolate their mycelia. Antioxidant activity was measured using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging activity in vitro; the ethanol extract from H. ramosum mycelia (63.11 µmol Trolox/g) was more potent than that of other mushroom mycelia extracts. There was a proportional relationship (R2 = 0.7929) between DPPH radical scavenging activity and total phenolic content in extracts of different mushroom mycelia. We investigated the ability of H. ramosum mycelia to inducing NGF synthesis in vivo. Oral administration of H. ramosum mycelia significantly increased concentrations of NGF in the hippocampus of intact mice. These results are the first concerning antioxidant activity and NGF synthesis of H. ramosum mycelia. These mushroom mycelia could be useful as food and/or nutritional supplements because of certain biological functions.

  1. Hinokitiol inhibits vasculogenic mimicry activity of breast cancer stem/progenitor cells through proteasome-mediated degradation of epidermal growth factor receptor

    PubMed Central

    TU, DOM-GENE; YU, YUN; LEE, CHE-HSIN; KUO, YU-LIANG; LU, YIN-CHE; TU, CHI-WEN; CHANG, WEN-WEI

    2016-01-01

    Hinokitiol, alternatively known as β-thujaplicin, is a tropolone-associated natural compound with antimicrobial, anti-inflammatory and antitumor activity. Breast cancer stem/progenitor cells (BCSCs) are a subpopulation of breast cancer cells associated with tumor initiation, chemoresistance and metastatic behavior, and may be enriched by mammosphere cultivation. Previous studies have demonstrated that BCSCs exhibit vasculogenic mimicry (VM) activity via the epidermal growth factor receptor (EGFR) signaling pathway. The present study investigated the anti-VM activity of hinokitiol in BCSCs. At a concentration below the half maximal inhibitory concentration, hinokitiol inhibited VM formation of mammosphere cells derived from two human breast cancer cell lines. Hinokitiol was additionally indicated to downregulate EGFR protein expression in mammosphere-forming BCSCs without affecting the expression of messenger RNA. The protein stability of EGFR in BCSCs was also decreased by hinokitiol. The EGFR protein expression and VM formation capability of hinokitiol-treated BCSCs were restored by co-treatment with MG132, a proteasome inhibitor. In conclusion, the present study indicated that hinokitiol may inhibit the VM activity of BCSCs through stimulating proteasome-mediated EGFR degradation. Hinokitiol may act as an anti-VM agent, and may be useful for the development of novel breast cancer therapeutic agents. PMID:27073579

  2. Stimulation of casein kinase II by epidermal growth factor: Relationship between the physiological activity of the kinase and the phosphorylation state of its beta subunit

    SciTech Connect

    Ackerman, P.; Osheroff, N. ); Glover, C.V.C. )

    1990-01-01

    To determine relationships between the hormonal activation of casein kinase II and its phosphorylation state, epidermal growth factor (EGF)-treated and EGF-naive human A-431 carcinoma cells were cultured in the presence of ({sup 32}P)orthophosphate. Immunoprecipitation experiments indicated that casein kinase II in the cytosol of EGF-treated cells contained approximately 3-fold more incorporated ({sup 32}P)phosphate than did its counterpart in untreated cells. Levels of kinase phosphorylation paralleled levels of kinase activity over a wide range of EGF concentrations as well as over a time course of hormone action. Approximately 97% of the incorporated ({sup 32}P)phosphate was found in the {beta} subunit of casein kinase II. Both activated and hormone-naive kinase contained radioactive phosphoserine and phosphothreonine but no phosphotyronsine. On the basis of proteolytic mapping experiments, EGF treatment of A-431 cells led to an increase in the average ({sup 32}P)phosphate content (i.e., hyperphosphorylation) of casein kinase II {beta} subunit peptides which were modified prior to hormone treatment. Finally, the effect of alkaline phosphatase on the reaction kinetics of activated casein kinase II indicated that hormonal stimulation of the kinase resulted from the increase in its phosphorylation state.

  3. The mechanism and significance of synergistic induction of the expression of plasminogen activator inhibitor-1 by glucocorticoid and transforming growth factor beta in human ovarian cancer cells.

    PubMed

    Pan, Xiao-yu; Wang, Yan; Su, Jie; Huang, Gao-xiang; Cao, Dong-mei; Qu, Shen; Lu, Jian

    2015-05-15

    Plasminogen activator inhibitor-1 (PAI-1) plays a key role in tissue remodeling and tumor development by suppression of plasminogen activator function. Glucocorticoids (GCs) and transforming growth factor beta (TGF-β) signal pathways cross-talk to regulate gene expression, but the mechanism is poorly understood. Here we investigated the mechanism and significance of co-regulation of PAI-1 by TGF-β and dexamethasone (DEX), a synthetic glucocorticoid in ovarian cancer cells. We found that TGF-β and DEX showed rapidly synergistic induction of PAI-1 expression, which contributed to the early pro-adhesion effects. The synergistic induction effect was accomplished by several signal pathways, including GC receptor (GR) pathway and TGF-β-activated p38MAPK, ERK and Smad3 pathways. TGF-β-activated p38MAPK and ERK pathways cross-talked with GR pathway to augment the expression of PAI-1 through enhancing DEX-induced GR phosphorylation at Ser211 in ovarian cancer cells. These findings reveal possible novel mechanisms by which TGF-β pathways cooperatively cross-talk with GR pathway to regulate gene expression.

  4. A cluster region of AP-1 responsive elements is required for transcriptional activity of mouse ODC gene by hepatocyte growth factor.

    PubMed

    Bianchi, Laura; Tacchini, Lorenza; Matteucci, Emanuela; Desiderio, Maria Alfonsina

    2002-05-01

    Ornithine decarboxylase (ODC) activity is regulated by a variety of mechanisms including transcription, translation, and RNA and protein half-life. Since in mouse B16-F1 melanoma cells an early and remarkable (about 6-fold) increase in steady state mRNA levels was observed after hepatocyte growth factor (HGF) treatment, we investigated the transcriptional regulation of mouse ODC promoter. Transient transfection of various ODC-luciferase promoter constructs into the B16-Fl cells in combination with electrophoretic mobility shift assays identified the HGF-responsive element as a cluster of three AP-1 binding sites (-1660 to -1572). Even if each site differs from the canonical TPA responsive element for one nucleotide, only the first two AP-1 consensus sequences seemed to be functional since allowed DNA-binding activity of nuclear proteins after HGF treatment. Comparison of the results of transfection assays with the pOD2.5-luc (2.5 kb gene fragment) and with the construct deprived of the AP-1 cluster pOD-B-luc showed that this 50 bp region was required for ODC transactivating activity in response to HGF. Since in B16-F1 cells HGF increased AP-1 activity and the mRNA expression of various AP-1 subunits, we may conclude that HGF-induced transcription of mouse ODC was largely due to triggering of AP-1 pathway. PMID:12054494

  5. Differential responsiveness of luteinized human granulosa cells to gonadotropins and insulin-like growth factor I for induction of aromatase activity

    SciTech Connect

    Christman, G.M.; Randolph, J.F. Jr.; Peegel, H.; Menon, K.M. )

    1991-06-01

    The objective of this study was to examine the in vitro responsiveness of cultured luteinized human granulosa cells over time to insulin-like growth factor 1 (IGF-1), human follicle-stimulating hormone (FSH), and human chorionic gonadotropin (hCG) for the induction of aromatase activity. Granulosa cells were retrieved from preovulatory follicles in patients undergoing in vitro fertilization. Cells were cultured for a period of 72 hours or 10 days. The ability of hCG, human FSH, and/or IGF-I to induce aromatase activity was assayed by the stereospecific release of tritium from (1B-3H)androstenedione. Short-term cultures (72 hours) demonstrated a marked rise in aromatase activity in response to human FSH and IGF-I, whereas a smaller response to hCG was observed. In contrast, 10-day cultures demonstrated responsiveness predominantly to hCG rather than human FSH for the induction of aromatase activity with no remarkable effect of IGF-I. Luteinized human granulosa cells undergo a transformation from an initial human FSH and IGF-I responsive state to an hCG responsive state in long-term cultures.

  6. Requirement for active glycogen synthase kinase-3β in TGF-β1 upregulation of connective tissue growth factor (CCN2/CTGF) levels in human gingival fibroblasts

    PubMed Central

    Bahammam, Maha; Black, Samuel A.; Sume, Siddika Selva; Assaggaf, Mohammad A.; Faibish, Michael

    2013-01-01

    Connective tissue growth factor (CCN2/CTGF) mediates transforming growth factor-β (TGF-β)-induced fibrosis. Drug-induced gingival overgrowth is tissue specific. Here the role of the phosphoinositol 3-kinase (PI3K) pathway in mediating TGF-β1-stimulated CCN2/CTGF expression in primary human adult gingival fibroblasts and human adult lung fibroblasts was compared. Data indicate that PI3K inhibitors attenuate upregulation of TGF-β1-induced CCN2/CTGF expression in human gingival fibroblasts independent of reducing JNK MAP kinase activation. Pharmacologic inhibitors and small interfering (si)RNA-mediated knockdown studies indicate that calcium-dependent isoforms and an atypical isoform of protein kinase C (PKC-δ) do not mediate TGF-β1-stimulated CCN2/CTGF expression in gingival fibroblasts. As glycogen synthase kinase-3β (GSK-3β) can undergo phosphorylation by the PI3K/pathway, the effects of GSK-3β inhibitor kenpaullone and siRNA knockdown were investigated. Data in gingival fibroblasts indicate that kenpaullone attenuates TGF-β1-mediated CCN2/CTGF expression. Activation of the Wnt canonical pathways with Wnt3a, which inhibits GSK-3β, similarly inhibits TGF-β1-stimulated CCN2/CTGF expression. In contrast, inhibition of GSK-3β by Wnt3a does not inhibit, but modestly stimulates, CCN2/CTGF levels in primary human adult lung fibroblasts and is β-catenin dependent, consistent with previous studies performed in other cell models. These data identify a novel pathway in gingival fibroblasts in which inhibition of GSK-3β attenuates CCN2/CTGF expression. In adult lung fibroblasts inhibition of GSK-3β modestly stimulates TGF-β1-regulated CCN2/CTGF expression. These studies have potential clinical relevance to the tissue specificity of drug-induced gingival overgrowth. PMID:23824844

  7. Parsing ERK Activation Reveals Quantitatively Equivalent Contributions From Epidermal Growth Factor Receptor and HER2 In Human Mammary Epithelial Cells

    SciTech Connect

    Hendriks, Bart S.; Orr, Galya; Wells, Alan H.; Wiley, H. S.; Lauffenburger, Douglas A.

    2005-02-18

    HER2, a member of the EGFR tyrosine kinase family, functions as an accessory EGFR signaling component and alters EGFR trafficking by heterodimerization. HER2 overexpression leads to aberrant cell behavior including enhanced proliferation and motility. Here we apply a combination of computational modeling and quantitative experimental studies of the dynamic interactions between EGFR and HER2, and their downstream activation of extracellular signal-related kinase (ERK) to understand this complex signaling system. Using cells expressing different levels of HER2 relative to the EGFR, we can separate relative contributions of EGFR and HER2 to signaling amplitude and duration. Based on our model calculations, we demonstrate that, in contrast with previous suggestions in the literature, the intrinsic capabilities of EGFR and HER2 to activated ERK are quantitatively equivalent . We find that HER2-mediated effects on EGFR dimerization and trafficking are sufficient to explain the detected HER2-mediated amplification of EGF-induced ERK signaling. Our model suggests that transient amplification of ERK activity by HER2 arises predominantly from the 2-to-1 stoichiometry of receptor kinase to bound ligand in EGFR/HER2 heterodimers compared to the 1-to-1 stoichiometry of the EGFR homodimer, but alterations in receptor trafficking, with resultant EGFR sparing, cause the sustained HER2-mediated enhancement of ERK signaling.

  8. Activation of A(1) adenosine or mGlu3 metabotropic glutamate receptors enhances the release of nerve growth factor and S-100beta protein from cultured astrocytes.

    PubMed

    Ciccarelli, R; Di Iorio, P; Bruno, V; Battaglia, G; D'Alimonte, I; D'Onofrio, M; Nicoletti, F; Caciagli, F

    1999-09-01

    Pharmacological activation of A(1) adenosine receptor with 2-chloro-N6-cyclopentyladenosine (CCPA) or mGlu3 metabotropic glutamate receptors with (2S,2'R,3'R)-2-(2', 3'-dicarboxycyclopropyl)glycine (DCG-IV) or aminopyrrolidine-2R, 4R-dicarboxylate (2R,4R-APDC) enhanced the release of nerve growth factor (NGF) or S-100beta protein from rat cultured astrocytes. Stimulation of release by CCPA and DCG-IV or 2R,4R-APDC was inhibited by the A(1) adenosine receptor antagonist 8-cyclopentyl-1, 3-dipropylxanthine and by the mGlu2/3 receptor antagonist (2S,1'S, 2'S,3'R)-2-(2'-carboxy-3'-phenylcyclopropyl)glycine (PCCG-4), respectively. Time-course studies revealed a profound difference between the release of S-100beta protein and the release of NGF in response to extracellular signals. Stimulation of S-100beta protein exhibited rapid kinetics, peaking after 1 h of drug treatment, whereas the enhancement of NGF release was much slower, requiring at least 6 h of A(1) adenosine or mGlu3 receptor activation. In addition, stimulation of NGF but not S-100beta release was substantially reduced in cultures treated with the protein synthesis inhibitor cycloheximide. In addition, a 6-8 h treatment of cultured astrocytes with A(1) or mGlu3 receptor agonists increased the levels of both NGF mRNA and NGF-like immunoreactive proteins, including NGF prohormone. We conclude that activation of A(1) adenosine or mGlu3 receptors produces pleiotropic effects in astrocytes, stimulating the synthesis and/or the release of protein factors. Astrocytes may therefore become targets for drugs that stimulate the local production of neurotrophic factors in the CNS, and this may provide the basis for a novel therapeutic strategy in chronic neurodegenerative disorders. PMID:10457374

  9. Increase in transforming growth factor-beta in the brain during infection is related to fever, not depression of spontaneous motor activity.

    PubMed

    Matsumura, S; Shibakusa, T; Fujikawa, T; Yamada, H; Inoue, K; Fushiki, T

    2007-02-01

    When viral infection occurs, this information is transmitted to the brain, and symptoms such as fever and tiredness are induced. One of the causes of these symptoms is the secretion of proinflammatory cytokines in blood and the brain. In this study, the i.p. administration of polyinosinic:polycytidylic acid (poly I:C), a synthetic double-stranded RNA, to rats was used as an infection model. Poly I:C decreased spontaneous motor activity (SMA) 2 h after i.p. administration, and this decrease was maintained thereafter. The concentration of active transforming growth factor-beta (TGF-beta) in cerebrospinal fluid (CSF) increased 1 h after the administration. This increase occurred earlier than those in the concentrations of other proinflammatory cytokines, such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), in serum. The intracisternal administration of an anti-TGF-beta antibody partially inhibited fever induced by poly I:C administration; however, this treatment did not affect the decrease in SMA. Furthermore, intracisternal administration of TGF-beta raised the body temperature. These results indicate that TGF-beta in the brain, which was increased by poly I:C administration, is associated with fever but not with a decrease in SMA.

  10. The Procognitive and Synaptogenic Effects of Angiotensin IV–Derived Peptides Are Dependent on Activation of the Hepatocyte Growth Factor/c-Met System

    PubMed Central

    Benoist, Caroline C.; Kawas, Leen H.; Zhu, Mingyan; Tyson, Katherine A.; Stillmaker, Lori; Appleyard, Suzanne M.; Wright, John W.

    2014-01-01

    A subset of angiotensin IV (AngIV)–related molecules are known to possess procognitive/antidementia properties and have been considered as templates for potential therapeutics. However, this potential has not been realized because of two factors: 1) a lack of blood-brain barrier–penetrant analogs, and 2) the absence of a validated mechanism of action. The pharmacokinetic barrier has recently been overcome with the synthesis of the orally active, blood-brain barrier–permeable analog N-hexanoic-tyrosine-isoleucine-(6) aminohexanoic amide (dihexa). Therefore, the goal of this study was to elucidate the mechanism that underlies dihexa’s procognitive activity. Here, we demonstrate that dihexa binds with high affinity to hepatocyte growth factor (HGF) and both dihexa and its parent compound Norleucine 1-AngIV (Nle1-AngIV) induce c-Met phosphorylation in the presence of subthreshold concentrations of HGF and augment HGF-dependent cell scattering. Further, dihexa and Nle1-AngIV induce hippocampal spinogenesis and synaptogenesis similar to HGF itself. These actions were inhibited by an HGF antagonist and a short hairpin RNA directed at c-Met. Most importantly, the procognitive/antidementia capacity of orally delivered dihexa was blocked by an HGF antagonist delivered intracerebroventricularly as measured using the Morris water maze task of spatial learning. PMID:25187433

  11. Heterogeneous nuclear ribonucleoprotein K and nucleolin as transcriptional activators of the vascular endothelial growth factor promoter through interaction with secondary DNA structures

    PubMed Central

    Uribe, Diana J.; Guo, Kexiao; Shin, Yoon-Joo; Sun, Daekyu

    2011-01-01

    The human vascular endothelial growth factor (VEGF) promoter contains a polypurine/polypyrimidine (pPu/pPy) tract that is known to play a critical role in its transcriptional regulation. This pPu/pPy tract undergoes a conformational transition between B-DNA, single stranded DNA and atypical secondary DNA structures such as G-quadruplexes and i-motifs. We studied the interaction of the cytosine-rich (C-rich) and guanine-rich (G-rich) strands of this tract with transcription factors heterogeneous nuclear ribonucleoprotein (hnRNP) K and nucleolin, respectively, both in vitro and in vivo and their potential role in the transcriptional control of VEGF. Using chromatin immunoprecipitation (ChIP) assay for our in vivo studies and electrophoretic mobility shift assay (EMSA) for our in vitro studies, we demonstrated that both nucleolin and hnRNP K bind selectively to the G- and C-rich sequences, respectively, in the pPu/pPy tract of the VEGF promoter. The small interfering RNA (siRNA)-mediated silencing of either nucleolin or hnRNP K resulted in the down-regulation of basal VEGF gene, suggesting that they act as activators of VEGF transcription. Taken together, the identification of transcription factors that can recognize and bind to atypical DNA structures within the pPu/pPy tract will provide new insight into mechanisms of transcriptional regulation of the VEGF gene. PMID:21466159

  12. growl: Growth factor and growth rate of expanding universes

    NASA Astrophysics Data System (ADS)

    Hamilton, Andrew J. S.

    2015-12-01

    Growl calculates the linear growth factor Da and its logarithmic derivative dln D/dln a in expanding Friedmann-Robertson-Walker universes with arbitrary matter and vacuum densities. It permits rapid and stable numerical evaluation.

  13. Cross-talk between human mast cells and bronchial epithelial cells in plasminogen activator inhibitor-1 production via transforming growth factor-β1.

    PubMed

    Cho, Seong H; Lee, Sun H; Kato, Atsushi; Takabayashi, Tetsuji; Kulka, Marianna; Shin, Soon C; Schleimer, Robert P

    2015-01-01

    Previous reports suggest that plasminogen activator inhibitor-1 (PAI-1) promotes airway remodeling and that human and mouse mast cells (MCs) are an important source of PAI-1. In the present study we investigated MC-epithelial cell (EC) interactions in the production of PAI-1. We stimulated the human MC line LAD2 with IgE-receptor cross-linking and collected the supernatants. We incubated the human bronchial EC line BEAS-2B with the LAD2 supernatants and measured the level of PAI-1. When the supernatants from IgE-stimulated LAD2 were added to BEAS-2B, there was a significant enhancement of PAI-1 production by BEAS-2B. When we treated the MC supernatants with a transforming growth factor (TGF)-β1 neutralizing antibody, the MC-derived induction of PAI-1 from BEAS-2B was completely abrogated. Although TGF-β1 mRNA was constitutively expressed in resting LAD2, it was not highly induced by IgE-mediated stimulation. Nonetheless, active TGF-β1 protein was significantly increased in LAD2 after IgE-mediated stimulation. Active TGF-β1 produced by primary cultured human MCs was significantly reduced in the presence of a chymase inhibitor, suggesting a role of MC chymase as an activator of latent TGF-β1. This study indicates that stimulation of human MCs by IgE receptor cross-linking triggers activation of TGF-β1, at least in part via chymase, which in turn induces the production of PAI-1 by bronchial ECs. Our data suggest that human MCs may play an important role in airway remodeling in asthma as a direct source of PAI-1 and by activating bronchial ECs to produce further PAI-1 via a TGF-β1-mediated activation pathway.

  14. From pure compounds to complex exposure: Effects of dietary cadmium and lignans on estrogen, epidermal growth factor receptor, and mitogen activated protein kinase signaling in vivo.

    PubMed

    Ali, Imran; Hurmerinta, Teija; Nurmi, Tarja; Berglund, Marika; Rüegg, Joelle; Poutanen, Matti; Halldin, Krister; Mäkelä, Sari; Damdimopoulou, Pauliina

    2016-06-24

    Exposure to environmental endocrine active compounds correlates with altered susceptibility to disease in human populations. Chemical risk assessment is single compound based, although exposure often takes place as heterogeneous mixtures of man-made and natural substances within complex matrices like diet. Here we studied whether the effects of cadmium and enterolactone on endocrine endpoints in dietary exposure can be predicted based on pure compound effects. Ovariectomized estrogen reporter ERE-luciferase (ERE-luc) mice were maintained on diets that intrinsically contain increasing concentrations of cadmium and enterolactone precursors for three and 21 days. The activation of the ERE-luc, epidermal growth factor receptor (EGFR), mitogen activated protein kinase (MAPK)-ERK1/2, and classical estrogen responses were measured. Interactions between the diets and endogenous hormone were evaluated by challenging the animals with 17β-estradiol. Compared to animals on basal purified diet, mice consuming experimental diets were exposed to significantly higher levels of cadmium and enterolactone, yet the exposure remained comparable to typical human dietary intake. Surprisingly, we could not detect effects on endpoints regulated by pure enterolactone, such as ERE-luc activation. However, cadmium accumulation in the liver was accompanied with activation of EGFR and MAPK-ERK1/2 in line with our earlier CdCl2 studies. Further, attenuation of 17β-estradiol-induced ERE-luc response in liver by experimental diets was observed. Our findings indicate that the exposure context can have substantial effects on the activity of endocrine active compounds in vivo. Thus, whenever possible, a context that mimics human exposure should be tested along with pure compounds. PMID:27108949

  15. Integrin αvβ3 mediates the synergetic regulation of core-binding factor α1 transcriptional activity by gravity and insulin-like growth factor-1 through phosphoinositide 3-kinase signaling.

    PubMed

    Dai, Zhongquan; Guo, Feima; Wu, Feng; Xu, Hongjie; Yang, Chao; Li, Jinqiao; Liang, Peilong; Zhang, Hongyu; Qu, Lina; Tan, Yingjun; Wan, Yumin; Li, Yinghui

    2014-12-01

    Mechanical stimulation and biological factors coordinately regulate bone development and regeneration; however, the underlying mechanisms are poorly understood. Microgravity induces bone loss, which may be partly related to the development of resistance to local cytokines, including insulin-like growth factor 1 (IGF-1). Here, we report the involvement of integrin αvβ3 in microgravity-associated bone loss. An established OSE-3T3 cell model was stably transfected with a 6OSE2 (Osteoblast-Specific Element 2)-luciferase reporter and cultured under simulated microgravity (SMG) and hypergravity (HG) conditions in the presence or absence of IGF-1, the disintegrin echistatin, the phosphoinositide 3-kinase (PI3K) inhibitor LY294002, or combinations of these agents. Activity of core-binding factor α1 (Cbfa1), an essential transcription factor for osteoblastic differentiation and osteogenesis, was reflected by luciferase activity. Different gravity conditions affected the induction of IGF-1 and subsequent effects on Cbfa1 transcription activity. SMG and HG influenced the expression and activity of integrin αvβ3 and phosphorylation level of p85. LY294002 inhibited the effects of HG or IGF-1 on Cbfa1 activity, indicating that HG and IGF-1 could increase Cbfa1 activity via PI3K signaling. Inhibition of integrin αvβ3 by echistatin attenuated the induction of IGF-1 and thus its effect on Cbfa1 activity under normal and HG conditions. Co-immunoprecipitation demonstrated that integrin β3 interacted with insulin receptor substrate 1, and that this interaction was decreased under SMG and increased under HG conditions. These results suggest that integrin αvβ3 mediates the synergetic regulation of Cbfa1 transcription activity by gravity and IGF-1 via PI3K signaling.

  16. Oxidatively modified LDL contains phospholipids with platelet-activating factor-like activity and stimulates the growth of smooth muscle cells.

    PubMed Central

    Heery, J M; Kozak, M; Stafforini, D M; Jones, D A; Zimmerman, G A; McIntyre, T M; Prescott, S M

    1995-01-01

    Oxidative modification of lipoproteins is believed to be important in the genesis of atherosclerosis. We established cultures of smooth muscle cells (SMC) and exposed them to native LDL or oxidized LDL. Oxidized LDL, but not native LDL, was mitogenic as measured by incorporation of [3H]-thymidine into DNA. This effect was concentration dependent, averaged 288% of control, and was blocked by a platelet-activating factor (PAF) receptor antagonist. We hypothesized that phospholipids with PAF-like activity were generated during the oxidation of LDL. To test this hypothesis we extracted phospholipids from copper-oxidized LDL and assayed for PAF-like activity. Phospholipids extracted from oxidized LDL and purified by HPLC induced neutrophil adhesion equivalent to PAF (10 nM) and were mitogenic for smooth muscle cells. These effects were not seen with phospholipids extracted from native LDL and were blocked by two structurally different, competitive antagonists of the PAF receptor. The effects of these lipids were also abolished by pretreating them with PAF acetylhydrolase. Finally, we used Chinese hamster ovary cells that had seen stably transfected with a cDNA for the PAF receptor to confirm that phospholipids from oxidized LDL act via this receptor. We found that PAF (control) and the oxidized phospholipids each induced release of arachidonic acid from the transfected cells, but had no effect on wildtype Chinese hamster ovary cells, which lack the PAF receptor. This effect was also blocked by a PAF receptor antagonist. Thus, phospholipids generated during oxidative modification of LDL may participate in atherosclerosis by stimulating SMC proliferation and leukocyte activation. Images PMID:7593619

  17. Human prostatic tumor cells in culture produce growth and differentiation factors active on osteoblasts: a new biological and clinical parameter for prostatic carcinoma.

    PubMed

    Festuccia, C; Teti, A; Bianco, P; Guerra, F; Vicentini, C; Tennina, R; Villanova, I; Sciortino, G; Bologna, M

    1997-01-01

    Prostate cancer (PRCA) cells metastasize to bone with high frequency, inducing typical osteosclerotic lesions. To establish if local stimuli on the bone tissue may derive from metastatic colonies of prostatic origin, we evaluated the biologic activities secreted by human prostatic epithelium and effective on osteoblast-like cells in vitro. Supernatant from short-term tissue cultures of human prostatic tissue samples obtained from PRCA (35 cases) and benign prostatic hyperplasia (BPH, 12 cases) patients were applied to three models of cells with osteoblastic phenotype: two normal [rabbit osteoblasts (OB) and rat periosteal cells (PO)] and one transformed (human osteosarcoma cell line, MG63). Proliferative activity was monitored through enzymatic reduction of tetrazolium salts and expressed as relative mitogenic activities (RMA). Analysis of proliferation and alkaline phosphatase (ALP) activity, a marker of osteoblast function, demonstrates that conditioned media (CM) from PRCA cultures stimulate both growth and activity of osteoblast-like cells to a greater extent compared to CM from BPH. Furthermore, cell growth and activity of osteoblast-like cells are progressively increased by CM derived from patients with stage B (tumor confined within the prostate capsule), stage C (locally invasive tumor), and stage D (invasive tumor with distant metastasis) disease. One of the mechanisms potentially underlying the CM-stimulated effects on bone cells is associated with the urokinase (uPA) enzyme route, whose release progressively increases with the stage of disease. However, antibodies against uPA and p-aminobenzamidine (a low molecular weight urokinase inhibitor) treatment, which both inhibit the proliferative and differentiative effects induced by exogenous urokinase, partially slow down the effects of CM from PRCA tissue cultures, suggesting that additional factors are secreted by prostatic tumor cells in vitro. In conclusion, we show that the mitogenic and differentiative

  18. Reduced growth factor requirement of keloid-derived fibroblasts may account for tumor growth

    SciTech Connect

    Russell, S.B.; Trupin, K.M.; Rodriguez-Eaton, S.; Russell, J.D.; Trupin, J.S.

    1988-01-01

    Keloids are benign dermal tumors that form during an abnormal wound-healing process is genetically susceptible individuals. Although growth of normal and keloid cells did not differ in medium containing 10% (vol/vol) fetal bovine serum, keloid culture grew to significantly higher densities than normal cells in medium containing 5% (vol/vol) fetal bovine serum, keloid cultures grew to significantly higher densities than normal cells in medium containing 5% (vol/vol) plasma or 1% fetal bovine serum. Conditioned medium from keloid cultures did not stimulate growth of normal cells in plasma nor did it contain detectable platelet-derived growth factor or epidermal growth factor. Keloid fibroblasts responded differently than normal adult fibroblasts to transforming growth factor ..beta... Whereas transforming growth factor ..beta.. reduced growth stimulation by epidermal growth factor in cells from normal adult skin or scars, it enhanced the activity of epidermal growth factor in cells from normal adult skin or scars, it enhanced the activity of epidermal growth factor in cells from keloids. Normal and keloid fibroblasts also responded differently to hydrocortisone: growth was stimulated in normal adult cells and unaffected or inhibited in keloid cells. Fetal fibroblasts resembled keloid cells in their ability to grow in plasma and in their response to hydrocortisone. The ability of keloid fibroblasts to grow to higher cell densities in low-serum medium than cells from normal adult skin or from normal early or mature scars suggests that a reduced dependence on serum growth factors may account for their prolonged growth in vivo. Similarities between keloid and fetal cells suggest that keloids may result from the untimely expression of growth-control mechanism that is developmentally regulated.

  19. Relationships between insulin-like growth factor-I, milk yield, body condition score, and postpartum luteal activity in high-producing dairy cows.

    PubMed

    Tamadon, Amin; Kafi, Mojtaba; Saeb, Mehdi; Mirzaei, Abdolah; Saeb, Saedeh

    2011-01-01

    The relations between body condition score (BCS), milk yield, serum insulin-like growth factor-I (IGF-I) profile, and luteal activity were investigated in postpartum dairy cows. Seventy-one healthy high-producing multiparous Holstein cows were subjected to transrectal ultrasound scanning twice weekly from the first to the eighth week postpartum. Blood samples were collected twice weekly to measure serum progesterone (P4) and every 2 weeks to detect serum IGF-I concentrations. BCS was monitored weekly after calving. Cows with serum P4 concentrations ≥1 ng/ml on at least two consecutive samplings were considered to have commenced luteal activity. Commencement of luteal activity (C-LA) was observed earlier than 45 days postpartum in 71.8% of cows while 28.2% showed C-LA later than 45 days. Prolonged luteal phase was the most common abnormal pattern of luteal activity observed. Cows with a C-LA earlier than 45 days postpartum had higher (P ≤ 0.05) mean serum concentrations of IGF-I than those with later C-LA. In addition, cows which showed C-LA earlier than 45 days postpartum had more optimal productive indices including shorter calving to conception interval and calving to first service interval (P ≤ 0.05), and fewer services per conception (P = 0.07). C-LA was significantly later in cows that lost more than 0.5 BCS units within 3 weeks postpartum than in those that lost less than 0.5 units BCS during the same interval (P = 0.02). We conclude that high-producing dairy cows with higher postpartum serum IGF-I concentrations have earlier commencement and normal luteal activity, and better reproductive performance. Severity and duration of BCS loss adversely affect commencement of luteal activity.

  20. Antitumor activity of the insulin-like growth factor-I receptor kinase inhibitor NVP-AEW541 in musculoskeletal tumors.

    PubMed

    Scotlandi, Katia; Manara, Maria Cristina; Nicoletti, Giordano; Lollini, Pier-Luigi; Lukas, Stella; Benini, Stefania; Croci, Stefania; Perdichizzi, Stefania; Zambelli, Diana; Serra, Massimo; García-Echeverría, Carlos; Hofmann, Francesco; Picci, Piero

    2005-05-01

    Identification of new drugs is strongly needed for sarcomas. Insulin-like growth factor-I receptor (IGF-IR) was found to provide a major contribution to the malignant behavior of these tumors, therefore representing a very promising therapeutic target. In this study, we analyzed the therapeutic potential of a novel kinase inhibitor of IGF-IR, NVP-AEW541, in Ewing's sarcoma, osteosarcoma, and rhabdomyosarcoma, the three most frequent solid tumors in children and adolescents. NVP-AEW541 inhibits IGF-I-mediated receptor activation and downstream signaling. Ewing's sarcoma cells were generally found to be more sensitive to the effects of this drug compared with rhabdomyosarcoma and osteosarcoma, in agreement with the high dependency of this neoplasm to IGF-IR signaling. NVP-AEW541 induced a G1 cell cycle block in all cells tested, whereas apoptosis was observed only in those cells that show a high level of sensitivity. Concurrent exposure of cells to NVP-AEW541 and other chemotherapeutic agents resulted in positive interactions with vincristine, actinomycin D, and ifosfamide and subadditive effects with doxorubicin and cisplatin. Accordingly, combined treatment with NVP-AEW541 and vincristine significantly inhibited tumor growth of Ewing's sarcoma xenografts in nude mice. Therefore, results encourage inclusion of this drug especially in the treatment of patients with Ewing's sarcoma. For the broadest applicability and best efficacy in sarcomas, NVP-AEW541 may be combined with vincristine, actinomycin D, and ifosfamide, three major drugs in the treatment of sarcomas.

  1. Inhibition of transforming growth factor-beta-induced liver fibrosis by a retinoic acid derivative via the suppression of Col 1A2 promoter activity.

    PubMed

    Yang, Kun-Lin; Chang, Wen-Teng; Hung, Kuo-Chen; Li, Eric I C; Chuang, Chia-Chang

    2008-08-22

    Transforming growth factor-beta1 (TGF-beta1) mediates expression of collagen 1A2 (Col 1A2) gene via a synergistic cooperation between Smad2/Smad3 and Sp1, both act on the Col 1A2 gene promoter. In our previous study, we reported that a retinoic acid derivative obtained from Phellinus linteus (designated PL) antagonizes TGF-beta-induced liver fibrosis through regulation of ROS and calcium influx. In this continuing study we seek further the effect of PL on the Smad signaling pathway. We used a Col 1A2 promoter-luciferase construct to study the action of PL on Smad through TGF-beta. We found that PL decreases the promoter activity of Col 1A2, hinders the translocalization of phosphorylated Smad2/3-Smad 4 complex from cytosol into nucleus and inhibits Sp1 binding activity. These results suggest that PL inhibits TGF-beta1-induced Col 1A2 promoter activity through blocking ROS and calcium influx as well as impeding Sp1 binding and translocalization of pSmad 2/3-Smad4 complex into nucleus.

  2. Role of NF-κB activation in matrix metalloproteinase 9, vascular endothelial growth factor and interleukin 8 expression and secretion in human breast cancer cells.

    PubMed

    Li, Caijuan; Guo, Sufen; Shi, Tiemei

    2013-04-01

    The aims of this study were to assess the effects and potential mechanisms of parthenolide on the expression of vascular endothelial growth factor (VEGF), interleukin 8 (IL-8) and matrix metalloproteinase 9 (MMP-9) in human breast cancer cell line MDA-MB-231. After incubation with different concentrations of parthenolide for 24 h, MDA-MB-231 cells were collected, and the expressions of VEGF, IL-8 and MMP-9 were measured by real-time PCR and Western blot. The secretions of VEGF, IL-8 and MMP-9 in culture supernatant of MDA-MB-231 cells were then measured with ELISA assays. The NF-κB DNA-binding activity of breast cancer cells treated with parthenolide was analyzed using electrophoretic mobility assays. The real-time PCR and Western blot data showed that the expressions of VEGF, IL-8 and MMP-9 were significantly inhibited by parthenolide at both transcription level and protein level in MDA-MB-231 cells. ELISA results also confirmed these effects at a secretion level. The electrophoretic mobility assay results demonstrated that parthenolide can inhibit NF-κB DNA-binding activity of the breast cancer cells. Hence, the expression of VEGF, IL-8 and MMP-9 may be suppressed by parthenolide through the inhibition of NF-κB DNA-binding activity in MDA-MB-231 cells.

  3. Inhibition of transforming growth factor β-activated kinase 1 prevents inflammation-related cartilage degradation in osteoarthritis

    PubMed Central

    Cheng, Jin; Hu, Xiaoqing; Dai, Linghui; Zhang, Xin; Ren, Bo; Shi, Weili; Liu, Zhenlong; Duan, Xiaoning; Zhang, Jiying; Fu, Xin; Chen, Wenqing; Ao, Yingfang

    2016-01-01

    Osteoarthritis (OA) is a common debilitating joint disorder, there’s still no available disease-modifying drug for OA currently. This study aims to explore the role of TAK1 in OA pathogenesis and therapeutic efficiency of TAK1 inhibition for OA. The contribution of TAK1 to OA pathogenesis was investigated by intra-articular injection of TAK1-encoding adenovirus in rats. TAK1 inhibitor 5Z-7-induced expression changes of extracellular matrix (ECM)-related genes were detected by real-time PCR. The protective effect of 5Z-7 against OA progression was evaluated in a post-traumatic OA rat model. Our results showed that intra-articular injection of Ad-Tak1 induced cartilage destruction and OA-related cytokine secretion in rat joints. TAK1 inhibition by 5Z-7 efficiently blocked NF-κB, JNK and p38 pathways activation in OA chondrocytes and synoviocytes, Meanwhile, 5Z-7 significantly decreased the expression of matrix-degrading enzymes and pro-inflammatory cytokine, while increased ECM protein expression, which are all crucial components in OA. 5Z-7 also ameliorated ECM loss in OA cartilage explants. More importantly, 5Z-7 significantly protected against cartilage destruction in a rat model of OA. In conclusion, our findings provide the first in vivo evidence that TAK1 contributes to OA by disrupting cartilage homeostasis, thus represents an ideal target for OA treatment, with 5Z-7 as a candidate therapeutic. PMID:27682596

  4. Platelet-derived growth factor-D modulates extracellular matrix homeostasis and remodeling through TIMP-1 induction and attenuation of MMP-2 and MMP-9 gelatinase activities

    SciTech Connect

    Borkham-Kamphorst, Erawan Alexi, Pascal; Tihaa, Lidia; Haas, Ute; Weiskirchen, Ralf

    2015-02-13

    Platelet-derived growth factor-D (PDGF-D) is a more recent recognized growth factor involved in the regulation of several cellular processes, including cell proliferation, transformation, invasion, and angiogenesis by binding to and activating its cognate receptor PDGFR-β. After bile duct ligation or in the carbon tetrachloride-induced hepatic fibrosis model{sub ,} PDGF-D showed upregulation comparable to PDGF-B. Moreover, adenoviral PDGF-D gene transfer induced hepatic stellate cell proliferation and liver fibrosis. We here investigated the molecular mechanism of PDGF-D involvement in liver fibrogenesis. Therefore, the GRX mouse cell line was stimulated with PDGF-D and evaluated for fibrotic markers and PDGF-D signaling pathways in comparison to the other PDGF isoforms. We found that PDGF-D failed to enhance Col I and α-smooth muscle actin (α-SMA) production but has capacity to upregulate expression of the tissue inhibitor of metalloprotease 1 (TIMP-1) resulting in attenuation of MMP-2 and MMP-9 gelatinase activity as indicated by gelatinase zymography. This phenomenon was restored through application of a PDGF-D neutralizing antibody. Unexpectedly, PDGF-D incubation decreased both PDGFR-α and -β in mRNA and protein levels, and PDGF-D phosphorylated typrosines specific for PDGFR-α and -β. We conclude that PDGF-D intensifies fibrogenesis by interfering with the fibrolytic activity of the TIMP-1/MMP system and that PDGF-D signaling is mediated through both PDGF-α and -β receptors. - Highlights: • PDGF-D signals through PDGF receptor type α and β. • PDGF-D modulates extracellular matrix homeostasis and remodeling. • Like PDGF-B, PDGF-D triggers phosphorylation of PLC-γ, Akt/PKB, JNK, ERK1/2, and p38. • PDGF-D induces TIMP-1 expression through ERK and p38 MAPK. • PDGF-D attenuates MMP-2 and MMP-9 gelatinase activities.

  5. Transforming Growth Factor β1 (TGF-β1) Activates Hepcidin mRNA Expression in Hepatocytes.

    PubMed

    Chen, Simeng; Feng, Teng; Vujić Spasić, Maja; Altamura, Sandro; Breitkopf-Heinlein, Katja; Altenöder, Jutta; Weiss, Thomas S; Dooley, Steven; Muckenthaler, Martina U

    2016-06-17

    The hepatic hormone hepcidin is the master regulator of systemic iron homeostasis. Its expression level is adjusted to alterations in iron levels, inflammatory cues, and iron requirements for erythropoiesis. Bone morphogenetic protein 6 (BMP6) contributes to the iron-dependent control of hepcidin. In addition, TGF-β1 may stimulate hepcidin mRNA expression in murine hepatocytes and human leukocytes. However, receptors and downstream signaling proteins involved in TGF-β1-induced hepcidin expression are still unclear. Here we show that TGF-β1 treatment of mouse and human hepatocytes, as well as ectopic expression of TGF-β1 in mice, increases hepcidin mRNA levels. The hepcidin response to TGF-β1 depends on functional TGF-β1 type I receptor (ALK5) and TGF-β1 type II receptor (TβRII) and is mediated by a noncanonical mechanism that involves Smad1/5/8 phosphorylation. Interestingly, increasing availability of canonical Smad2/3 decreases TGF-β1-induced hepcidin regulation, whereas the BMP6-hepcidin signal was enhanced, indicating a signaling component stoichiometry-dependent cross-talk between the two pathways. Although ALK2/3-dependent hepcidin activation by BMP6 can be modulated by each of the three hemochromatosis-associated proteins: HJV (hemojuvelin), HFE (hemochromatosis protein), and TfR2 (transferrin receptor 2), these proteins do not control the ALK5-mediated hepcidin response to TGF-β1. TGF-β1 mRNA levels are increased in mouse models of iron overload, indicating that TGF-β1 may contribute to hepcidin synthesis under these conditions. In conclusion, these data demonstrate that a complex regulatory network involving TGF-β1 and BMP6 may control the sensing of systemic and/or hepatic iron levels.

  6. Environmental factors influencing growth and pubertal development.

    PubMed Central

    Delemarre-van de Waal, H A

    1993-01-01

    Postnatal growth is based on hereditary signals and environmental factors in a complex regulatory network. Each factor must be in an optimal state for normal growth of the child. Fetal conditions may also have consequences on postnatal height. Intrauterine growth retardation can be recovered postnatally, although postnatal growth remains depressed in about one-third of cases. After birth, the environment may exert either a positive or negative effect on growth. In underdeveloped countries, malnutrition plays a major role in inhibiting the growth process. Children from families of higher socioeconomic classes are taller than their coevals in the lower socioeconomic groups. Urbanization also has a positive effect on growth. Better child care is supported by sufficient food supply, appropriate health and sanitation services, and a higher level of education. Over the last century, these factors have induced a taller stature and a more rapid maturity in Europe, North America, and Australia; a phenomenon which has been referred to as "the secular trend" in growth. Recently, a secular trend has also been reported in some developing countries. Although urbanization in general appears to be associated with better conditions of living, this is not the case in the slums of South America or in Africa where rural children are better off than children living in the poor cities. This paper describes in more detail the different hereditary and environmental factors that act during the fetal period and postnatally, and which play a role in human growth and pubertal development. PMID:8243404

  7. Activation of the Yeast UBI4 Polyubiquitin Gene by Zap1 Transcription Factor via an Intragenic Promoter Is Critical for Zinc-deficient Growth.

    PubMed

    MacDiarmid, Colin W; Taggart, Janet; Jeong, Jeeyon; Kerdsomboon, Kittikhun; Eide, David J

    2016-09-01

    Stability of many proteins requires zinc. Zinc deficiency disrupts their folding, and the ubiquitin-proteasome system may help manage this stress. In Saccharomyces cerevisiae, UBI4 encodes five tandem ubiquitin monomers and is essential for growth in zinc-deficient conditions. Although UBI4 is only one of four ubiquitin-encoding genes in the genome, a dramatic decrease in ubiquitin was observed in zinc-deficient ubi4Δ cells. The three other ubiquitin genes were strongly repressed under these conditions, contributing to the decline in ubiquitin. In a screen for ubi4Δ suppressors, a hypomorphic allele of the RPT2 proteasome regulatory subunit gene (rpt2(E301K)) suppressed the ubi4Δ growth defect. The rpt2(E301K) mutation also increased ubiquitin accumulation in zinc-deficient cells, and by using a ubiquitin-independent proteasome substrate we found that proteasome activity was reduced. These results suggested that increased ubiquitin supply in suppressed ubi4Δ cells was a consequence of more efficient ubiquitin release and recycling during proteasome degradation. Degradation of a ubiquitin-dependent substrate was restored by the rpt2(E301K) mutation, indicating that ubiquitination is rate-limiting in this process. The UBI4 gene was induced ∼5-fold in low zinc and is regulated by the zinc-responsive Zap1 transcription factor. Surprisingly, Zap1 controls UBI4 by inducing transcription from an intragenic promoter, and the resulting truncated mRNA encodes only two of the five ubiquitin repeats. Expression of a short transcript alone complemented the ubi4Δ mutation, indicating that it is efficiently translated. Loss of Zap1-dependent UBI4 expression caused a growth defect in zinc-deficient conditions. Thus, the intragenic UBI4 promoter is critical to preventing ubiquitin deficiency in zinc-deficient cells. PMID:27432887

  8. Vascular growth factors in neuropsychiatry

    PubMed Central

    Newton, Samuel S.; Fournier, Neil M.; Duman, Ronald S.

    2014-01-01

    Recent advances in understanding the cellular and molecular basis of psychiatric illnesses have shed light on the important role played by trophic factors in modulating functional parameters associated with disease causality and drug action. Disease mechanisms are now thought to involve multiple cell types, including neurons and endothelial cells. These functionally distinct but interactively coupled cell types engage in cellular cross talk via shared and common signaling molecules. Dysregulation in their cellular signaling pathways influences brain function and alters behavioral performance. Multifunctional trophic factors such as VEGF and EPO that possess both neurotrophic and angiogenic actions are of particular interest due to their ability to rescue structural and plasticity deficits in neurons and vasculature. Obtaining insight into the behavioral, cellular and molecular actions of multi-functional trophic factors has the potential to open new and transformative therapeutic approaches. PMID:23475069

  9. Decorin: A Growth Factor Antagonist for Tumor Growth Inhibition

    PubMed Central

    Järvinen, Tero A. H.; Prince, Stuart

    2015-01-01

    Decorin (DCN) is the best characterized member of the extracellular small leucine-rich proteoglycan family present in connective tissues, typically in association with or “decorating” collagen fibrils. It has substantial interest to clinical medicine owing to its antifibrotic, anti-inflammatory, and anticancer effects. Studies on DCN knockout mice have established that a lack of DCN is permissive for tumor development and it is regarded as a tumor suppressor gene. A reduced expression or a total disappearance of DCN has been reported to take place in various forms of human cancers during tumor progression. Furthermore, when used as a therapeutic molecule, DCN has been shown to inhibit tumor progression and metastases in experimental cancer models. DCN affects the biology of various types of cancer by targeting a number of crucial signaling molecules involved in cell growth, survival, metastasis, and angiogenesis. The active sites for the neutralization of different growth factors all reside in different parts of the DCN molecule. An emerging concept that multiple proteases, especially those produced by inflammatory cells, are capable of cleaving DCN suggests that native DCN could be inactivated in a number of pathological inflammatory conditions. In this paper, we review the role of DCN in cancer. PMID:26697491

  10. Protein Disulfide Isomerase Is Required for Platelet-derived Growth Factor-induced Vascular Smooth Muscle Cell Migration, Nox1 NADPH Oxidase Expression, and RhoGTPase Activation

    PubMed Central

    Pescatore, Luciana A.; Bonatto, Diego; Forti, Fábio L.; Sadok, Amine; Kovacic, Hervé; Laurindo, Francisco R. M.

    2012-01-01

    Vascular Smooth Muscle Cell (VSMC) migration into vessel neointima is a therapeutic target for atherosclerosis and postinjury restenosis. Nox1 NADPH oxidase-derived oxidants synergize with growth factors to support VSMC migration. We previously described the interaction between NADPH oxidases and the endoplasmic reticulum redox chaperone protein disulfide isomerase (PDI) in many cell types. However, physiological implications, as well as mechanisms of such association, are yet unclear. We show here that platelet-derived growth factor (PDGF) promoted subcellular redistribution of PDI concomitant to Nox1-dependent reactive oxygen species production and that siRNA-mediated PDI silencing inhibited such reactive oxygen species production, while nearly totally suppressing the increase in Nox1 expression, with no change in Nox4. Furthermore, PDI silencing inhibited PDGF-induced VSMC migration assessed by distinct methods, whereas PDI overexpression increased spontaneous basal VSMC migration. To address possible mechanisms of PDI effects, we searched for PDI interactome by systems biology analysis of physical protein-protein interaction networks, which indicated convergence with small GTPases and their regulator RhoGDI. PDI silencing decreased PDGF-induced Rac1 and RhoA activities, without changing their expression. PDI co-immunoprecipitated with RhoGDI at base line, whereas such association was decreased after PDGF. Also, PDI co-immunoprecipitated with Rac1 and RhoA in a PDGF-independent way and displayed detectable spots of perinuclear co-localization with Rac1 and RhoGDI. Moreover, PDI silencing promoted strong cytoskeletal changes: disorganization of stress fibers, decreased number of focal adhesions, and reduced number of RhoGDI-containing vesicular recycling adhesion structures. Overall, these data suggest that PDI is required to support Nox1/redox and GTPase-dependent VSMC migration. PMID:22773830

  11. Hepatocyte growth factor inhibits hypoxia/reoxygenation-induced activation of xanthine oxidase in endothelial cells through the JAK2 signaling pathway

    PubMed Central

    Zhang, Ying Qian; Hu, Shun Ying; Chen, Yun Dai; Guo, Ming Zhou; Wang, Shan

    2016-01-01

    Vascular endothelial cells (ECs) appear to be one of the primary targets of hypoxia/reoxygenation (H/R) injury. In our previous study, we demonstrated that hepatocyte growth factor (HGF) exhibited a protective effect in cardiac microvascular endothelial cells (CMECs) subjected to H/R by inhibiting xanthine oxidase (XO) by reducing the cytosolic Ca2+ concentration increased in response to H/R. The precise mechanisms through which HGF inhibits XO activation remain to be determined. In the present study, we examined the signaling pathway through which HGF regulates Ca2+ concentrations and the activation of XO during H/R in primary cultured rat CMECs. CMECs were exposed to 4 h of hypoxia and 1 h of reoxygenation. The protein expression of XO and the activation of the phosphoinositide 3-kinase (PI3K), janus kinase 2 (JAK2) and p38 mitogen-activated protein kinase (p38 MAPK) signaling pathways were detected by western blot analysis. Cytosolic calcium (Ca2+) concentrations and reactive oxygen species (ROS) levels were measured by flow cytometry. The small interfering RNA (siRNA)-mediated knockdown of XO inhibited the increase in ROS production induced by H/R. LY294002 and AG490 inhibited the H/R-induced increase in the production and activation of XO. The PI3K and JAK2 signaling pathways were activated by H/R. The siRNA-mediated knockdown of PI3K and JAK2 also inhibited the increase in the production of XO protein. HGF inhibited JAK2 activation whereas it had no effect on PI3K activation. The siRNA-mediated knockdown of JAK2 prevented the increase in cytosolic Ca2+ induced by H/R. Taken together, these findings suggest that H/R induces the production and activation of XO through the JAK2 and PI3K signaling pathways. Furthermore, HGF prevents XO activation following H/R primarily by inhibiting the JAK2 signaling pathway and in turn, inhibiting the increase in cytosolic Ca2+. PMID:27573711

  12. Transforming growth factor-{beta} inhibits CCAAT/enhancer-binding protein expression and PPAR{gamma} activity in unloaded bone marrow stromal cells

    SciTech Connect

    Ahdjoudj, S.; Kaabeche, K.; Holy, X.; Fromigue, O.; Modrowski, D.; Zerath, E.; Marie, P.J. . E-mail: pierre.marie@larib.inserm.fr

    2005-02-01

    The molecular mechanisms regulating the adipogenic differentiation of bone marrow stromal cells in vivo remain largely unknown. In this study, we investigated the regulatory effects of transforming growth factor beta-2 (TGF-{beta}2) on transcription factors involved in adipogenic differentiation induced by hind limb suspension in rat bone marrow stromal cells in vivo. Time course real-time quantitative reverse-transcription polymerase chain reaction (RT-PCR) analysis of gene expression showed that skeletal unloading progressively increases the expression of CCAAT/enhancer-binding protein (C/EBP){alpha} and C/EBP{beta} {alpha} at 5 days in bone marrow stromal cells resulting in increased peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}2) transcripts at 7 days. TGF-{beta}2 administration in unloaded rats corrected the rise in C/EBP{alpha} and C/EBP{beta} transcripts induced by unloading in bone marrow stromal cells. This resulted in inhibition of PPAR{gamma}2 expression that was associated with increased Runx2 expression. Additionally, the inhibition of C/EBP{alpha} and C/EBP{beta} expression by TGF-{beta}2 was associated with increased PPAR{gamma} serine phosphorylation in bone marrow stromal cells, a mechanism that inhibits PPAR{gamma} transactivating activity. The sequential inhibitory effect of TGF-{beta}2 on C/EBP{alpha}, C/EBP{beta}, and PPAR{gamma}2 resulted in reduced LPL expression and abolition of bone marrow stromal cell adipogenic differentiation, which contributed to prevent bone loss induced by skeletal unloading. We conclude that TGF-{beta}2 inhibits the excessive adipogenic differentiation of bone marrow stromal cells induced by skeletal unloading by inhibiting C/EBP{alpha}, C/EBP{beta}, and PPAR{gamma} expression and activity, which provides a sequential mechanism by which TGF-{beta}2 regulates adipogenic differentiation of bone marrow stromal cells in vivo.

  13. Enhanced Mitogenic Activity of Recombinant Human Vascular Endothelial Growth Factor VEGF121 Expressed in E. coli Origami B (DE3) with Molecular Chaperones

    PubMed Central

    Kaplan, Ondřej; Zárubová, Jana; Mikulová, Barbora; Filová, Elena; Bártová, Jiřina; Bačáková, Lucie; Brynda, Eduard

    2016-01-01

    We describe the production of a highly-active mutant VEGF variant, α2-PI1-8-VEGF121, which contains a substrate sequence for factor XIIIa at the aminoterminus designed for incorporation into a fibrin gel. The α2-PI1-8-VEGF121 gene was synthesized, cloned into a pET-32a(+) vector and expressed in Escherichia coli Origami B (DE3) host cells. To increase the protein folding and the solubility, the resulting thioredoxin-α2-PI1-8-VEGF121 fusion protein was co-expressed with recombinant molecular chaperones GroES/EL encoded by independent plasmid pGro7. The fusion protein was purified from the soluble fraction of cytoplasmic proteins using affinity chromatography. After cleavage of the thioredoxin fusion part with thrombin, the target protein was purified by a second round of affinity chromatography. The yield of purified α2-PI1-8-VEGF121 was 1.4 mg per liter of the cell culture. The α2-PI1-8-VEGF121 expressed in this work increased the proliferation of endothelial cells 3.9–8.7 times in comparison with commercially-available recombinant VEGF121. This very high mitogenic activity may be caused by co-expression of the growth factor with molecular chaperones not previously used in VEGF production. At the same time, α2-PI1-8-VEGF121 did not elicit considerable inflammatory activation of human endothelial HUVEC cells and human monocyte-like THP-1 cells. PMID:27716773

  14. Lactic Acid is Elevated in Idiopathic Pulmonary Fibrosis and Induces Myofibroblast Differentiation Via pH-Dependent Activation of Transforming Growth Factor

    SciTech Connect

    Kottman, R. M.; Kulkarni, Ajit A.; Smolnycki, Katie A.; Lyda, Elizabeth; Dahanayake, Thinesh; Salibi, Rami; Honnons, Sylvie; Jones, Carolyn; Isern, Nancy G.; Hu, Jian Z.; Nathan, Steven D.; Grant, Geraldine; Phipps, Richard P.; Sime, Patricia J.

    2012-10-15

    Rationale: Idiopathic pulmonary fibrosis (IPF) is a complex disease for which the pathogenesis is poorly understood. In this study, we identified lactic acid as a metabolite that is elevated in the lung tissue of patients with IPF. Objectives: This study examines the effect of lactic acid on myofibroblast differentiation and pulmonary fibrosis. Methods:We used metabolomic analysis to examine cellular metabolism in lung tissuefrom patients with IPFanddeterminedthe effects of lactic acid and lactate dehydrogenase-5 (LDH5) overexpression on myofibroblast differentiation and transforming growth factor (TGF)-b activation in vitro. Measurements and Main Results: Lactic acid concentrations from healthy and IPF lung tissue were determined by nuclear magnetic resonance spectroscopy; a-smooth muscle actin, calponin, and LDH5 expression were assessed by Western blot of cell culture lysates. Lactic acid and LDH5 were significantly elevated in IPF lung tissue compared with controls. Physiologic concentrations of lactic acid induced myofibroblast differentiation via activation of TGF-b. TGF-b induced expression of LDH5 via hypoxia-inducible factor 1a (HIF1a). Importantly, overexpression of both HIF1a and LDH5 in human lung fibroblasts induced myofibroblast differentiation and synergized with low dose TGF-b to induce differentiation. Furthermore, inhibition of both HIF1a and LDH5 inhibited TGF-b–induced myofibroblast differentiation. Conclusions: We have identified the metabolite lactic acid as an important mediator of myofibroblast differentiation via a pHdependent activation of TGF-b. We propose that the metabolic milieu of the lung, and potentially other tissues, is an important driving force behind myofibroblast differentiation and potentially the initiation and progression of fibrotic disorders.

  15. Direct binding of hepatocyte growth factor and vascular endothelial growth factor to CD44v6

    PubMed Central

    Volz, Yvonne; Koschut, David; Matzke-Ogi, Alexandra; Dietz, Marina S.; Karathanasis, Christos; Richert, Ludovic; Wagner, Moritz G.; Mély, Yves; Heilemann, Mike; Niemann, Hartmut H.; Orian-Rousseau, Véronique

    2015-01-01

    CD44v6, a member of the CD44 family of transmembrane glycoproteins is a co-receptor for two receptor tyrosine kinases (RTKs), Met and VEGFR-2 (vascular endothelial growth factor receptor 2). CD44v6 is not only required for the activation of these RTKs but also for signalling. In order to understand the role of CD44v6 in Met and VEGFR-2 activation and signalling we tested whether CD44v6 binds to their ligands, HGF (hepatocyte growth factor) and VEGF (vascular endothelial growth factor), respectively. FACS analysis and cellular ELISA showed binding of HGF and VEGF only to cells expressing CD44v6. Direct binding of CD44v6 to HGF and VEGF was demonstrated in pull-down assays and the binding affinities were determined using MicroScale Thermophoresis, fluorescence correlation spectroscopy and fluorescence anisotropy. The binding affinity of CD44v6 to HGF is in the micromolar range in contrast with the high-affinity binding measured in the case of VEGF and CD44v6, which is in the nanomolar range. These data reveal a heparan sulfate-independent direct binding of CD44v6 to the ligands of Met and VEGFR-2 and suggest different roles of CD44v6 for these RTKs. PMID:26181364

  16. The Fibroblast Growth Factor signaling pathway

    PubMed Central

    Ornitz, David M; Itoh, Nobuyuki

    2015-01-01

    The signaling component of the mammalian Fibroblast Growth Factor (FGF) family is comprised of eighteen secreted proteins that interact with four signaling tyrosine kinase FGF receptors (FGFRs). Interaction of FGF ligands with their signaling receptors is regulated by protein or proteoglycan cofactors and by extracellular binding proteins. Activated FGFRs phosphorylate specific tyrosine residues that mediate interaction with cytosolic adaptor proteins and the RAS-MAPK, PI3K-AKT, PLCγ, and STAT intracellular signaling pathways. Four structurally related intracellular non-signaling FGFs interact with and regulate the family of voltage gated sodium channels. Members of the FGF family function in the earliest stages of embryonic development and during organogenesis to maintain progenitor cells and mediate their growth, differentiation, survival, and patterning. FGFs also have roles in adult tissues where they mediate metabolic functions, tissue repair, and regeneration, often by reactivating developmental signaling pathways. Consistent with the presence of FGFs in almost all tissues and organs, aberrant activity of the pathway is associated with developmental defects that disrupt organogenesis, impair the response to injury, and result in metabolic disorders, and cancer. © 2015 Wiley Periodicals, Inc. PMID:25772309

  17. PI3K/Akt is involved in brown adipogenesis mediated by growth differentiation factor-5 in association with activation of the Smad pathway

    SciTech Connect

    Hinoi, Eiichi; Iezaki, Takashi; Fujita, Hiroyuki; Watanabe, Takumi; Odaka, Yoshiaki; Ozaki, Kakeru; Yoneda, Yukio

    2014-07-18

    Highlights: • Akt is preferentially phosphorylated in BAT and sWAT of aP2-GDF5 mice. • PI3K/Akt signaling is involved in GDF5-induced brown adipogenesis. • PI3K/Akt signaling regulates GDF5-induced Smad5 phosphorylation. - Abstract: We have previously demonstrated promotion by growth differentiation factor-5 (GDF5) of brown adipogenesis for systemic energy expenditure through a mechanism relevant to activating the bone morphological protein (BMP) receptor/mothers against decapentaplegic homolog (Smad)/peroxisome proliferator-activated receptor gamma co-activator 1α (PGC-1α) pathway. Here, we show the involvement of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in brown adipogenesis mediated by GDF5. Overexpression of GDF5 in cells expressing adipocyte protein-2 markedly accelerated the phosphorylation of Smad1/5/8 and Akt in white and brown adipose tissues. In brown adipose tissue from heterozygous GDF5{sup Rgsc451} mutant mice expressing a dominant-negative (DN) GDF5 under obesogenic conditions, the basal phosphorylation of Smad1/5/8 and Akt was significantly attenuated. Exposure to GDF5 not only promoted the phosphorylation of both Smad1/5/8 and Akt in cultured brown pre-adipocytes, but also up-regulated Pgc1a and uncoupling protein-1 expression in a manner sensitive to the PI3K/Akt inhibitor Ly294002 as well as retroviral infection with DN-Akt. GDF5 drastically promoted BMP-responsive luciferase reporter activity in a Ly294002-sensitive fashion. Both Ly294002 and DN-Akt markedly inhibited phosphorylation of Smad5 in the nuclei of brown pre-adipocytes. These results suggest that PI3K/Akt signals play a role in the GDF5-mediated brown adipogenesis through a mechanism related to activation of the Smad pathway.

  18. Identification and characterization of transforming growth factor β-activated kinase 1 from Litopenaeus vannamei involved in anti-bacterial host defense.

    PubMed

    Wang, Sheng; Li, Haoyang; Lǚ, Kai; Qian, Zhe; Weng, Shaoping; He, Jianguo; Li, Chaozheng

    2016-05-01

    LvTAK1, a member of transforming growth factor β-activated kinase 1 (TAK1) families, has been identified from Litopenaeus vannamei in this study. The full length of LvTAK1 is 2670 bp, including a 2277 bp open reading frame (ORF) that encoded a putative protein of 758 amino acids with a calculated molecular weight of ∼83.4 kDa LvTAK1 expression was most abundant in muscles and was up-regulated in gills after LPS, Vibrio parahaemolyticus, Staphylococcus aureus, Poly (I:C) and WSSV challenge. Both in vivo and in vitro experiments indicated that LvTAK1 could activate the expression of several antimicrobial peptide genes (AMPs). In addition, the dsRNA-mediated knockdown of LvTAK1 enhanced the susceptibility of shrimps to Vibrio parahaemolyticus, a kind of Gram-negative bacteria. These results suggested LvTAK1 played important roles in anti-bacterial infection. CoIP and subcellular localization assay demonstrated that LvTAK1 could interact with its binding protein LvTAB2, a key component of IMD pathway. Moreover, over-expression of LvTAK1 in Drosophila S2 cell could strongly induce the promoter activity of Diptericin (Dpt), a typical AMP which is used to read out of the activation of IMD pathway. These findings suggested that LvTAK1 could function as a component of IMD pathway. Interestingly, with the over-expression of LvTAK1 in S2 cell, the promoter activity of Metchnikowin (Mtk), a main target gene of Toll/Dif pathway, was up-regulated over 30 times, suggesting that LvTAK1 may also take part in signal transduction of the Toll pathway. In conclusion, we provided some evidences that the involvement of LvTAK1 in the regulation of both Toll and IMD pathways, as well as innate immune against bacterial infection in shrimp.

  19. Lnk is an important modulator of insulin-like growth factor-1/Akt/peroxisome proliferator-activated receptor-gamma axis during adipogenesis of mesenchymal stem cells

    PubMed Central

    Lee, Jun Hee; Lee, Sang Hun; Lee, Hyang Seon; Ji, Seung Taek; Jung, Seok Yun; Kim, Jae Ho; Bae, Sun Sik

    2016-01-01

    Adipogenic differentiation of mesenchymal stem cells (MSCs) is critical for metabolic homeosta