Systemic and Gene Modified Mesenchymal Stem Cell Therapy for Metastatic Prostate Cancer

DTIC Science & Technology

2009-05-01

downregulate the expression of growth factors , receptor tyrosine kinases, proteases, and AR both in vitro and in vivo only when the cells express high... growth , and apoptosis as shown in Figure 1A. Downregulation of growth factors , FGF, Mdk, PDGF, Ptn, TGFb1 and TGFb3, tyrosine kinase receptors Ffgr3 and... growth factors and receptor tyrosine kinases mainly in andro- gen-sensitive and AR-overexpressing cells. The effect was more pronounced in Erk, Ras, and

Theileria parva infection induces autocrine growth of bovine lymphocytes.

PubMed Central

Dobbelaere, D A; Coquerelle, T M; Roditi, I J; Eichhorn, M; Williams, R O

1988-01-01

Bovine lymphocytes infected with the parasite Theileria parva continuously secrete a growth factor that is essential for their proliferation in vitro and also constitutively express interleukin 2 receptors on their surface. Dilution of the secreted growth factor, caused by culturing cells at low density, results in retardation of culture growth. Human recombinant interleukin 2, however, effectively substitutes for the diluted growth factor by restoring normal growth rates and also allows Theileria-infected cells to be grown at low density without the use of feeder layers. Secretion of the growth factor and expression of the interleukin 2 receptor depend on the presence of the parasite in the cytoplasm of the host cell. Elimination of the parasite from the cell cytoplasm by the specific antitheilerial drug BW 720c results in the arrest of growth factor secretion and the disappearance of interleukin 2 receptors from the cell surface. This is accompanied by growth arrest and reversion of the infected cells to the morphology of resting lymphocytes. We propose that the continuous proliferation of infected cells in vitro is mediated by autocrine receptor activation. Images PMID:3133661

Niclosamide inhibits epithelial-mesenchymal transition and tumor growth in lapatinib-resistant human epidermal growth factor receptor 2-positive breast cancer.

PubMed

Liu, Junjun; Chen, Xiaosong; Ward, Toby; Mao, Yan; Bockhorn, Jessica; Liu, Xiaofei; Wang, Gen; Pegram, Mark; Shen, Kunwei

2016-02-01

Acquired resistance to lapatinib, a human epidermal growth factor receptor 2 kinase inhibitor, remains a clinical problem for women with human epidermal growth factor receptor 2-positive advanced breast cancer, as metastasis is commonly observed in these patients. Niclosamide, an anti-helminthic agent, has recently been shown to exhibit cytotoxicity to tumor cells with stem-like characteristics. This study was designed to identify the mechanisms underlying lapatinib resistance and to determine whether niclosamide inhibits lapatinib resistance by reversing epithelial-mesenchymal transition. Here, two human epidermal growth factor receptor 2-positive breast cancer cell lines, SKBR3 and BT474, were exposed to increasing concentrations of lapatinib to establish lapatinib-resistant cultures. Lapatinib-resistant SKBR3 and BT474 cells exhibited up-regulation of the phenotypic epithelial-mesenchymal transition markers Snail, vimentin and α-smooth muscle actin, accompanied by activation of nuclear factor-кB and Src and a concomitant increase in stem cell marker expression (CD44(high)/CD24(low)), compared to naive lapatinib-sensitive SKBR3 and BT474 cells, respectively. Interestingly, niclosamide reversed epithelial-mesenchymal transition, induced apoptosis and inhibited cell growth by perturbing aberrant signaling pathway activation in lapatinib-resistant human epidermal growth factor receptor 2-positive cells. The ability of niclosamide to alleviate stem-like phenotype development and invasion was confirmed. Collectively, our results demonstrate that lapatinib resistance correlates with epithelial-mesenchymal transition and that niclosamide inhibits lapatinib-resistant cell viability and epithelial-mesenchymal transition. These findings suggest a role of niclosamide or derivatives optimized for more favorable bioavailability not only in reversing lapatinib resistance but also in reducing metastatic potential during the treatment of human epidermal growth factor receptor 2-positive breast cancer. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of vitamin D(3)-binding protein-derived macrophage activating factor (GcMAF) on angiogenesis.

PubMed

Kanda, Shigeru; Mochizuki, Yasushi; Miyata, Yasuyoshi; Kanetake, Hiroshi; Yamamoto, Nobuto

2002-09-04

The vitamin D(3)-binding protein (Gc protein)-derived macrophage activating factor (GcMAF) activates tumoricidal macrophages against a variety of cancers indiscriminately. We investigated whether GcMAF also acts as an antiangiogenic factor on endothelial cells. The effects of GcMAF on angiogenic growth factor-induced cell proliferation, chemotaxis, and tube formation were examined in vitro by using cultured endothelial cells (murine IBE cells, porcine PAE cells, and human umbilical vein endothelial cells [HUVECs]) and in vivo by using a mouse cornea micropocket assay. Blocking monoclonal antibodies to CD36, a receptor for the antiangiogenic factor thrombospondin-1, which is also a possible receptor for GcMAF, were used to investigate the mechanism of GcMAF action. GcMAF inhibited the endothelial cell proliferation, chemotaxis, and tube formation that were all stimulated by fibroblast growth factor-2 (FGF-2), vascular endothelial growth factor-A, or angiopoietin 2. FGF-2-induced neovascularization in murine cornea was also inhibited by GcMAF. Monoclonal antibodies against murine and human CD36 receptor blocked the antiangiogenic action of GcMAF on the angiogenic factor stimulation of endothelial cell chemotaxis. In addition to its ability to activate tumoricidal macrophages, GcMAF has direct antiangiogenic effects on endothelial cells independent of tissue origin. The antiangiogenic effects of GcMAF may be mediated through the CD36 receptor.

Macropinocytosis of the PDGF β-receptor promotes fibroblast transformation by H-RasG12V

PubMed Central

Schmees, C.; Villaseñor, R.; Zheng, W.; Ma, H.; Zerial, M.; Heldin, C.-H.; Hellberg, C.

2012-01-01

Receptor tyrosine kinase (RTK) signaling is frequently increased in tumor cells, sometimes as a result of decreased receptor down-regulation. The extent to which the endocytic trafficking routes can contribute to such RTK hyperactivation is unclear. Here, we show for the first time that fibroblast transformation by H-RasG12V induces the internalization of platelet-derived growth factor β-receptor (PDGFRβ) by macropinocytosis, enhancing its signaling activity and increasing anchorage-independent proliferation. H-RasG12V transformation and PDGFRβ activation were synergistic in stimulating phosphatidylinositol (PI) 3-kinase activity, leading to receptor macropinocytosis. PDGFRβ macropinocytosis was both necessary and sufficient for enhanced receptor activation. Blocking macropinocytosis by inhibition of PI 3-kinase prevented the increase in receptor activity in transformed cells. Conversely, increasing macropinocytosis by Rabankyrin-5 overexpression was sufficient to enhance PDGFRβ activation in nontransformed cells. Simultaneous stimulation with PDGF-BB and epidermal growth factor promoted macropinocytosis of both receptors and increased their activation in nontransformed cells. We propose that H-Ras transformation promotes tumor progression by enhancing growth factor receptor signaling as a result of increased receptor macropinocytosis. PMID:22573884

Inhibition of Epidermal Growth Factor Receptor and Vascular Endothelial Growth Factor Receptor Phosphorylation on Tumor-Associated Endothelial Cells Leads to Treatment of Orthotopic Human Colon Cancer in Nude Mice1

PubMed Central

Sasaki, Takamitsu; Kitadai, Yasuhiko; Nakamura, Toru; Kim, Jang-Seong; Tsan, Rachel Z; Kuwai, Toshio; Langley, Robert R; Fan, Dominic; Kim, Sun-Jin; Fidler, Isaiah J

2007-01-01

The purpose of our study was to determine whether the dual inhibition of epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor (VEGFR) signaling pathways in tumor-associated endothelial cells can inhibit the progressive growth of human colon carcinoma in the cecum of nude mice. SW620CE2 human colon cancer cells growing in culture and orthotopically in the cecum of nude mice expressed a high level of transforming growth factor alpha (TGF-α) and vascular endothelial growth factor (VEGF) but were negative for EGFR, human epidermal growth factor receptor 2 (HER2), and VEGFR. Double immunofluorescence staining revealed that tumor-associated endothelial cells expressed EGFR, VEGFR2, phosphorylated EGFR (pEGFR), and phosphorylated VEGFR (pVEGFR). Treatment of mice with either 7H-pyrrolo [2,3-d]-pyrimidine lead scaffold (AEE788; an inhibitor of EGFR and VEGFR tyrosine kinase) or CPT-11 as single agents significantly inhibited the growth of cecal tumors (P < .01); this decrease was even more pronounced with AEE788 combined with CPT-11 (P < .001). AEE788 alone or combined with CPT-11 also inhibited the expression of pEGFR and pVEGFR on tumor-associated endothelial cells, significantly decreased vascularization and tumor cell proliferation, and increased the level of apoptosis in both tumor-associated endothelial cells and tumor cells. These data demonstrate that targeting EGFR and VEGFR signaling on tumor-associated endothelial cells provides a viable approach for the treatment of colon cancer. PMID:18084614

Toll-like receptor 4 promotes proliferation and apoptosis resistance in human papillomavirus-related cervical cancer cells through the Toll-like receptor 4/nuclear factor-κB pathway.

PubMed

Jiang, Ninghong; Xie, Feng; Guo, Qisang; Li, Ming-Qing; Xiao, Jingjing; Sui, Long

2017-06-01

Toll-like receptor 4 is overexpressed in various tumors, including cervical carcinoma. However, the role of Toll-like receptor 4 in cervical cancer remains controversial, and the underlying mechanisms are largely elusive. Therefore, Toll-like receptor 4 in cervical cancer and related mechanisms were investigated in this study. Quantitative reverse transcription polymerase chain reaction and western blot analyses were used to detect messenger RNA and protein levels in HeLa, Caski, and C33A cells with different treatments. Proliferation was quantified using Cell Counting Kit-8. Cell cycle distribution and apoptosis were assessed by flow cytometry. Higher levels of Toll-like receptor 4 expression were found in human papillomavirus-positive cells compared to human papillomavirus-negative cells. Proliferation of HeLa and Caski cells was promoted in lipopolysaccharide-stimulated groups but suppressed in short hairpin RNA-transfected groups. Apoptosis rates were lower in lipopolysaccharide-stimulated groups relative to short hairpin RNA-transfected groups. In addition, G2-phase distribution was enhanced when Toll-like receptor 4 was downregulated. Moreover, the pNF-κBp65 level was positively correlated with the Toll-like receptor 4 level in HeLa and Caski cells, though when an nuclear factor-κB inhibitor was applied to lipopolysaccharide-stimulated groups, the patterns of proliferation and apoptosis were opposite to those of the lipopolysaccharide-stimulated groups without inhibitor treatment. In conclusion, these data suggest that Toll-like receptor 4 promotes proliferation and apoptosis resistance in human papillomavirus-related cervical cancer cells at least in part through the Toll-like receptor 4/nuclear factor-κB pathway, which may be correlated with the occurrence and development of cervical carcinoma.

Regulation of cell growth by redox-mediated extracellular proteolysis of platelet-derived growth factor receptor beta.

PubMed

Okuyama, H; Shimahara, Y; Kawada, N; Seki, S; Kristensen, D B; Yoshizato, K; Uyama, N; Yamaoka, Y

2001-07-27

Redox-regulated processes are important elements in various cellular functions. Reducing agents, such as N-acetyl-l-cysteine (NAC), are known to regulate signal transduction and cell growth through their radical scavenging action. However, recent studies have shown that reactive oxygen species are not always involved in ligand-stimulated intracellular signaling. Here, we report a novel mechanism by which NAC blocks platelet-derived growth factor (PDGF)-induced signaling pathways in hepatic stellate cells, a fibrogenic player in the liver. Unlike in vascular smooth muscle cells, we found that reducing agents, including NAC, triggered extracellular proteolysis of PDGF receptor-beta, leading to desensitization of hepatic stellate cells toward PDGF-BB. This effect was mediated by secreted mature cathepsin B. In addition, type II transforming growth factor-beta receptor was also down-regulated. Furthermore, these events seemed to cause a dramatic improvement of rat liver fibrosis. These results indicated that redox processes impact the cell's response to growth factors by regulating the turnover of growth factor receptors and that "redox therapy" is promising for fibrosis-related disease.

Fibroblast growth factor receptor signaling crosstalk in skeletogenesis.

PubMed

Miraoui, Hichem; Marie, Pierre J

2010-11-02

Fibroblast growth factors (FGFs) play important roles in the control of embryonic and postnatal skeletal development by activating signaling through FGF receptors (FGFRs). Germline gain-of-function mutations in FGFR constitutively activate FGFR signaling, causing chondrocyte and osteoblast dysfunctions that result in skeletal dysplasias. Crosstalk between the FGFR pathway and other signaling cascades controls skeletal precursor cell differentiation. Genetic analyses revealed that the interplay of WNT and FGFR1 determines the fate and differentiation of mesenchymal stem cells during mouse craniofacial skeletogenesis. Additionally, interactions between FGFR signaling and other receptor tyrosine kinase networks, such as those mediated by the epidermal growth factor receptor and platelet-derived growth factor receptor α, were associated with excessive osteoblast differentiation and bone formation in the human skeletal dysplasia called craniosynostosis, which is a disorder of skull development. We review the roles of FGFR signaling and its crosstalk with other pathways in controlling skeletal cell fate and discuss how this crosstalk could be pharmacologically targeted to correct the abnormal cell phenotype in skeletal dysplasias caused by aberrant FGFR signaling.

Hypoxia-inducing factors as master regulators of stemness properties and altered metabolism of cancer- and metastasis-initiating cells

PubMed Central

Mimeault, Murielle; Batra, Surinder K

2013-01-01

Accumulating lines of experimental evidence have revealed that hypoxia-inducible factors, HIF-1α and HIF-2α, are key regulators of the adaptation of cancer- and metastasis-initiating cells and their differentiated progenies to oxygen and nutrient deprivation during cancer progression under normoxic and hypoxic conditions. Particularly, the sustained stimulation of epidermal growth factor receptor (EGFR), insulin-like growth factor-1 receptor (IGF-1R), stem cell factor (SCF) receptor KIT, transforming growth factor-β receptors (TGF-βRs) and Notch and their downstream signalling elements such as phosphatidylinositol 3′-kinase (PI3K)/Akt/molecular target of rapamycin (mTOR) may lead to an enhanced activity of HIFs. Moreover, the up-regulation of HIFs in cancer cells may also occur in the hypoxic intratumoral regions formed within primary and secondary neoplasms as well as in leukaemic cells and metastatic prostate and breast cancer cells homing in the hypoxic endosteal niche of bone marrow. The activated HIFs may induce the expression of numerous gene products such as induced pluripotency-associated transcription factors (Oct-3/4, Nanog and Sox-2), glycolysis- and epithelial-mesenchymal transition (EMT) programme-associated molecules, including CXC chemokine receptor 4 (CXCR4), snail and twist, microRNAs and angiogenic factors such as vascular endothelial growth factor (VEGF). These gene products in turn can play critical roles for high self-renewal ability, survival, altered energy metabolism, invasion and metastases of cancer cells, angiogenic switch and treatment resistance. Consequently, the targeting of HIF signalling network and altered metabolic pathways represents new promising strategies to eradicate the total mass of cancer cells and improve the efficacy of current therapies against aggressive and metastatic cancers and prevent disease relapse. PMID:23301832

Tumor necrosis factor-alpha inhibits stem cell factor-induced proliferation of human bone marrow progenitor cells in vitro. Role of p55 and p75 tumor necrosis factor receptors.

PubMed Central

Rusten, L S; Smeland, E B; Jacobsen, F W; Lien, E; Lesslauer, W; Loetscher, H; Dubois, C M; Jacobsen, S E

1994-01-01

Stem cell factor (SCF), a key regulator of hematopoiesis, potently synergizes with a number of hematopoietic growth factors. However, little is known about growth factors capable of inhibiting the actions of SCF. TNF-alpha has been shown to act as a bidirectional regulator of myeloid cell proliferation and differentiation. This study was designed to examine interactions between TNF-alpha and SCF. Here, we demonstrate that TNF-alpha potently and directly inhibits SCF-stimulated proliferation of CD34+ hematopoietic progenitor cells. Furthermore, TNF-alpha blocked all colony formation stimulated by SCF in combination with granulocyte colony-stimulating factor (CSF) or CSF-1. The synergistic effect of SCF observed in combination with GM-CSF or IL-3 was also inhibited by TNF-alpha, resulting in colony numbers similar to those obtained in the absence of SCF. These effects of TNF-alpha were mediated through the p55 TNF receptor, whereas little or no inhibition was signaled through the p75 TNF receptor. Finally, TNF-alpha downregulated c-kit cell-surface expression on CD34+ bone marrow cells, and this was predominantly a p55 TNF receptor-mediated event as well. Images PMID:7518828

TNF Receptor 2 Makes Tumor Necrosis Factor a Friend of Tumors

PubMed Central

Sheng, Yuqiao; Li, Feng; Qin, Zhihai

2018-01-01

Tumor necrosis factor (TNF) is widely accepted as a tumor-suppressive cytokine via its ubiquitous receptor TNF receptor 1 (TNFR1). The other receptor, TNFR2, is not only expressed on some tumor cells but also on suppressive immune cells, including regulatory T cells and myeloid-derived suppressor cells. In contrast to TNFR1, TNFR2 diverts the tumor-inhibiting TNF into a tumor-advocating factor. TNFR2 directly promotes the proliferation of some kinds of tumor cells. Also activating immunosuppressive cells, it supports immune escape and tumor development. Hence, TNFR2 may represent a potential target of cancer therapy. Here, we focus on expression and role of TNFR2 in the tumor microenvironment. We summarize the recent progress in understanding how TNFR2-dependent mechanisms promote carcinogenesis and tumor growth and discuss the potential value of TNFR2 in cancer treatment. PMID:29892300

TRAF molecules in cell signaling and in human diseases

PubMed Central

2013-01-01

The tumor necrosis factor receptor (TNF-R)-associated factor (TRAF) family of intracellular proteins were originally identified as signaling adaptors that bind directly to the cytoplasmic regions of receptors of the TNF-R superfamily. The past decade has witnessed rapid expansion of receptor families identified to employ TRAFs for signaling. These include Toll-like receptors (TLRs), NOD-like receptors (NLRs), RIG-I-like receptors (RLRs), T cell receptor, IL-1 receptor family, IL-17 receptors, IFN receptors and TGFβ receptors. In addition to their role as adaptor proteins, most TRAFs also act as E3 ubiquitin ligases to activate downstream signaling events. TRAF-dependent signaling pathways typically lead to the activation of nuclear factor-κBs (NF-κBs), mitogen-activated protein kinases (MAPKs), or interferon-regulatory factors (IRFs). Compelling evidence obtained from germ-line and cell-specific TRAF-deficient mice demonstrates that each TRAF plays indispensable and non-redundant physiological roles, regulating innate and adaptive immunity, embryonic development, tissue homeostasis, stress response, and bone metabolism. Notably, mounting evidence implicates TRAFs in the pathogenesis of human diseases such as cancers and autoimmune diseases, which has sparked new appreciation and interest in TRAF research. This review presents an overview of the current knowledge of TRAFs, with an emphasis on recent findings concerning TRAF molecules in signaling and in human diseases. PMID:23758787

Epidermal Growth Factor-Dependent Transformation by a Human EGF Receptor Proto-Oncogene

NASA Astrophysics Data System (ADS)

Velu, Thierry J.; Beguinot, Laura; Vass, William C.; Willingham, Mark C.; Merlino, Glenn T.; Pastan, Ira; Lowy, Douglas R.

1987-12-01

The epidermal growth factor (EGF) receptor gene EGFR has been placed in a retrovirus vector to examine the growth properties of cells that experimentally overproduce a full-length EGF receptor. NIH 3T3 cells transfected with the viral DNA or infected with the corresponding rescued retrovirus developed a fully transformed phenotype in vitro that required both functional EGFR expression and the presence of EGF in the growth medium. Cells expressing 4 × 105 EGF receptors formed tumors in nude mice, while control cells did not. Therefore, the EGFR retrovirus, which had a titer on NIH 3T3 cells that was greater than 107 focus-forming units per milliliter, can efficiently transfer and express this gene, and increased numbers of EGF receptors can contribute to the transformed phenotype.

Human Herpesvirus-8-Transformed Endothelial Cells Have Functionally Activated Vascular Endothelial Growth Factor/Vascular Endothelial Growth Factor Receptor

PubMed Central

Masood, Rizwan; Cesarman, Ethel; Smith, D. Lynne; Gill, Parkash S.; Flore, Ornella

2002-01-01

Kaposi’s sarcoma is a vascular tumor commonly associated with human immunodeficiency virus (HIV)-1 and human herpesvirus (HHV-8) also known as Kaposi’s sarcoma-associated herpesvirus. The principal features of this tumor are abnormal proliferation of vascular structures lined with spindle-shaped endothelial cells. HHV-8 may transform a subpopulation of endothelial cells in vitro via viral and cellular gene expression. We hypothesized that among the cellular genes, vascular endothelial growth factors (VEGFs) and their cognate receptors may be involved in viral-mediated transformation. We have shown that HHV-8-transformed endothelial cells (EC-HHV-8) express higher levels of VEGF, VEGF-C, VEGF-D, and PlGF in addition to VEGF receptors-1, -2, and -3. Furthermore, antibodies to VEGF receptor-2 inhibited cell proliferation and viability. Similarly, inhibition of VEGF gene expression with antisense oligonucleotides inhibited EC-HHV-8 cell proliferation/viability. The growth and viability of primary endothelial cells and a fibroblast cell line however were unaffected by either the VEGF receptor-2 antibody or the VEGF antisense oligodeoxynucleotides. VEGF and VEGF receptors are thus induced in EC-HHV-8 and participate in the transformation. Inhibitors of VEGF may thus modulate the disease process during development and progression. PMID:11786394

Kruppel-like Factor 9 is a Negative Regulator of Ligand-dependent Estrogen Receptor Alpha Signaling in Ishikawa Endometrial Adenocarcinoma Cells

USDA-ARS?s Scientific Manuscript database

Estrogen (E) and progesterone (P), acting through their respective receptors and other nuclear proteins, exhibit opposing activities in target cells. We previously reported that Krüppel-like factor 9 (KLF9) cooperates with progesterone receptor (PR) to facilitate P-dependent gene transcription in ut...

Screening anti-tumor compounds from Ligusticum wallichii using cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry.

PubMed

Zhang, Tao; Ding, Yuanyuan; An, Hongli; Feng, Liuxin; Wang, Sicen

2015-07-14

Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry was developed. Tyrosine 367 Cysteine-HEK293 cells were used as cell membrane stationary phase. Specificity and reproducibility of the cell membrane chromatography was evaluated using 1-tert-butyl-3-{2-[4-(diethylamino)butylamino]-6-(3,5-dimethoxyphenyl)pyrido[2,3-d]pyrimidin-7-yl}urea, Nimodipine and dexamethasone acetate. Then, anti-tumor components acting on Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 were screened and identified from extracts of Ligusticum wallichii. Components from the extract were retained on the cell membrane chromatographic column. The retained fraction was directly eluted into high-performance liquid chromatography with mass spectrometry system for separation and identification. Finally, Levistolide A was identified as an active component from Ligusticum wallichii extracts. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide-formazan colorimetric assay revealed that Levistolide A inhibits proliferation of overexpressing the mutated receptor cells with dose-dependent manner. Phosphorylation of fibroblast growth factor receptor 4 was also decrease under Levistolide A treatment. Flex dock simulation verified that Levistolide A could bind with the tyrosine kinase domain of fibroblast growth factor receptor 4. Therefore, Levistolide A screened by the cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry can arrest cell growth. In conclusion, the two-dimensional high-performance liquid chromatography method can screen and identify potential anti-tumor ingredients which specifically act on the tyrosine kinase domain of the mutated fibroblast growth factor receptor 4. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Cell-free synthesis of functional human epidermal growth factor receptor: Investigation of ligand-independent dimerization in Sf21 microsomal membranes using non-canonical amino acids

PubMed Central

Quast, Robert B.; Ballion, Biljana; Stech, Marlitt; Sonnabend, Andrei; Varga, Balázs R.; Wüstenhagen, Doreen A.; Kele, Péter; Schiller, Stefan M.; Kubick, Stefan

2016-01-01

Cell-free protein synthesis systems represent versatile tools for the synthesis and modification of human membrane proteins. In particular, eukaryotic cell-free systems provide a promising platform for their structural and functional characterization. Here, we present the cell-free synthesis of functional human epidermal growth factor receptor and its vIII deletion mutant in a microsome-containing system derived from cultured Sf21 cells. We provide evidence for embedment of cell-free synthesized receptors into microsomal membranes and asparagine-linked glycosylation. Using the cricket paralysis virus internal ribosome entry site and a repetitive synthesis approach enrichment of receptors inside the microsomal fractions was facilitated thereby providing analytical amounts of functional protein. Receptor tyrosine kinase activation was demonstrated by monitoring receptor phosphorylation. Furthermore, an orthogonal cell-free translation system that provides the site-directed incorporation of p-azido-L-phenylalanine is characterized and applied to investigate receptor dimerization in the absence of a ligand by photo-affinity cross-linking. Finally, incorporated azides are used to generate stable covalently linked receptor dimers by strain-promoted cycloaddition using a novel linker system. PMID:27670253

Neurotrophin Signaling and Stem Cells-Implications for Neurodegenerative Diseases and Stem Cell Therapy.

PubMed

Pramanik, Subrata; Sulistio, Yanuar Alan; Heese, Klaus

2017-11-01

Neurotrophins (NTs) are members of a neuronal growth factor protein family whose action is mediated by the tropomyosin receptor kinase (TRK) receptor family receptors and the p75 NT receptor (p75NTR), a member of the tumor necrosis factor (TNF) receptor family. Although NTs were first discovered in neurons, recent studies have suggested that NTs and their receptors are expressed in various types of stem cells mediating pivotal signaling events in stem cell biology. The concept of stem cell therapy has already attracted much attention as a potential strategy for the treatment of neurodegenerative diseases (NDs). Strikingly, NTs, proNTs, and their receptors are gaining interest as key regulators of stem cells differentiation, survival, self-renewal, plasticity, and migration. In this review, we elaborate the recent progress in understanding of NTs and their action on various stem cells. First, we provide current knowledge of NTs, proNTs, and their receptor isoforms and signaling pathways. Subsequently, we describe recent advances in the understanding of NT activities in various stem cells and their role in NDs, particularly Alzheimer's disease (AD) and Parkinson's disease (PD). Finally, we compile the implications of NTs and stem cells from a clinical perspective and discuss the challenges with regard to transplantation therapy for treatment of AD and PD.

A feedback mechanism controlling SCRAMBLED receptor accumulation and cell-type pattern in Arabidopsis.

PubMed

Kwak, Su-Hwan; Schiefelbein, John

2008-12-23

Cellular pattern formation in the root epidermis of Arabidopsis occurs in a position-dependent manner, generating root-hair (H) cells contacting two underlying cortical cells and nonhair (N) cells contacting one cortical cell. SCRAMBLED (SCM), a leucine-rich repeat receptor-like kinase (LRR-RLK), mediates this process through its effect on a downstream transcription factor regulatory network. After perception of a positional cue, the SCM signaling pathway is proposed to preferentially repress WEREWOLF (WER) transcription factor expression in H cells and thereby bias the outcome of mutual lateral inhibition acting between H and N cells. However, the molecular mechanism responsible for this preferential SCM signaling is unknown. Here, we analyze the distribution of the SCM receptor and the biological effect of altering its accumulation pattern. We find that SCM expression and accumulation in the epidermal cell layer is necessary and sufficient to direct the cell-type pattern. Further, SCM preferentially accumulates in H cells, and this accumulation pattern is dependent on the downstream transcription factors. Thus, SCM participates in an autoregulatory feedback loop, enabling cells engaged in SCM signaling to maintain high levels of SCM receptor, which provides a simple mechanism for reinforcing a bias in receptor-mediated signaling to ensure robust pattern formation.

Neurotensin-induced Erk1/2 phosphorylation and growth of human colonic cancer cells are independent from growth factors receptors activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Massa, Fabienne; Tormo, Aurelie; Beraud-Dufour, Sophie

2011-10-14

Highlights: {yields} We compare intracellular pathways of NT and EGF in HT29 cells. {yields} NT does not transactivate EGFR. {yields} Transactivation of EGFR is not a general rule in cancer cell growth. -- Abstract: Neurotensin (NT) promotes the proliferation of human colonic cancer cells by undefined mechanisms. We already demonstrated that, in the human colon adenocarcinoma cell line HT29, the effects of NT were mediated by a complex formed between the NT receptor-1 (NTSR1) and-3 (NTSR3). Here we examined cellular mechanisms that led to NT-induced MAP kinase phosphorylation and growth factors receptors transactivation in colonic cancer cells and proliferation inmore » HT29 cells. With the aim to identify upstream signaling involved in NT-elicited MAP kinase activation, we found that the stimulatory effects of the peptide were totally independent from the activation of the epidermal growth factor receptor (EGFR) both in the HT29 and the HCT116 cells. NT was unable to promote phosphorylation of EGFR and to compete with EGF for its binding to the receptor. Pharmacological approaches allowed us to differentiate EGF and NT signaling in HT29 cells since only NT activation of Erk1/2 was shown to be sensitive to PKC inhibitors and since only NT increased the intracellular level of calcium. We also observed that NT was not able to transactivate Insulin-like growth factor receptor. Our findings indicate that, in the HT29 and HCT116 cell lines, NT stimulates MAP kinase phosphorylation and cell growth by a pathway which does not involve EGF system but rather NT receptors which transduce their own intracellular effectors. These results indicate that depending on the cell line used, blocking EGFR is not the general rule to inhibit NT-induced cancer cell proliferation.« less

F-prostanoid receptor regulation of fibroblast growth factor 2 signaling in endometrial adenocarcinoma cells.

PubMed

Sales, Kurt J; Boddy, Sheila C; Williams, Alistair R W; Anderson, Richard A; Jabbour, Henry N

2007-08-01

Prostaglandin (PG) F(2alpha) is a potent bioactive lipid in the female reproductive tract, and exerts its function after coupling with its heptahelical G-protein-coupled receptor [F-series-prostanoid (FP) receptor] to initiate cell signaling and target gene transcription. In the present study, we found elevated expression of fibroblast growth factor (FGF) 2, FGF receptor 1 (FGFR1), and FP receptor, colocalized within the neoplastic epithelial cells of endometrial adenocarcinomas. We investigated a role for PGF(2alpha)-FP receptor interaction in modulating FGF2 expression and signaling using an endometrial adenocarcinoma cell line stably expressing the FP receptor to the levels detected in endometrial adenocarcinomas (FPS cells) and endometrial adenocarcinoma tissue explants. PGF(2alpha)-FP receptor activation rapidly induced FGF2 mRNA expression, and elevated FGF2 protein expression and secretion into the culture medium in FPS cells and endometrial adenocarcinoma explants. The effect of PGF(2alpha) on the expression and secretion of FGF2 could be abolished by treatment of FPS cells and endometrial tissues with an FP receptor antagonist (AL8810) and inhibitor of ERK (PD98059). Furthermore, we have shown that FGF2 can promote the expression of FGF2 and cyclooxygenase-2, and enhance proliferation of endometrial adenocarcinoma cells via the FGFR1 and ERK pathways, thereby establishing a positive feedback loop to regulate neoplastic epithelial cell function in endometrial adenocarcinomas.

Receptor for macrophage colony-stimulating factor transduces a signal decreasing erythroid potential in the multipotent hematopoietic EML cell line.

PubMed

Pawlak, G; Grasset, M F; Arnaud, S; Blanchet, J P; Mouchiroud, G

2000-10-01

To test the hypothesis that hematopoietic growth factors may influence lineage choice in pluripotent progenitor cells, we investigated the effects of macrophage colony-stimulating factor (M-CSF) on erythroid and myeloid potentials of multipotent EML cells ectopically expressing M-CSF receptor (M-CSFR). EML cells are stem cell factor (SCF)-dependent murine cells that give rise spontaneously to pre-B cells, burst-forming unit erythroid (BFU-E), and colony-forming unit granulocyte macrophage (CFU-GM). We determined BFU-E and CFU-GM frequencies among EML cells transduced with murine M-CSFR, human M-CSFR, or chimeric receptors, and cultivated in the presence of SCF, M-CSF, or both growth factors. Effects of specific inhibitors of signaling molecules were investigated. EML cells transduced with murine M-CSFR proliferated in response to M-CSF but also exhibited a sharp and rapid decrease in BFU-E frequency associated with an increase in CFU-GM frequency. In contrast, EML cells expressing human M-CSFR proliferated in response to M-CSF without any changes in erythroid or myeloid potential. Using chimeric receptors between human and murine M-CSFR, we showed that the effects of M-CSF on EML cell differentiation potential are mediated by a large region in the intracellular domain of murine M-CSFR. Furthermore, phospholipase C (PLC) inhibitor U73122 interfered with the negative effects of ligand-activated murine M-CSFR on EML cell erythroid potential. We propose that signaling pathways activated by tyrosine kinase receptors may regulate erythroid potential and commitment decisions in multipotent progenitor cells and that PLC may play a key role in this process.

The role of the Fas/FasL signaling pathway in environmental toxicant-induced testicular cell apoptosis: An update.

PubMed

Wang, Mei; Su, Ping

2018-04-01

The Fas/FasL signaling pathway is one of the major pathways that regulate apoptosis. Increasing studies have shown that the activation of the Fas/FasL signaling pathway is closely associated with testicular cell apoptosis. However, the mechanism involved is still unclear. We discuss recent findings regarding the molecular mechanisms by which environmental toxicants induce testicular pathology via Fas/FasL signaling. These findings suggest that Fas/FasL signaling is employed to impact the sensitivity (a response to external factors) of germ cells, disrupt steroidogenic hormone and cytokine metabolism mediated by Sertoli cells, and elicit the activation of NFAT (nuclear factor of activated T-cells) in Leydig cell apoptosis. Consequently, degeneration of testicular somatic (Sertoli and Leydig) and spermatogenic cells, leads to decreased numbers of mature sperm and subsequently translates into infertility issues. Collectively, these findings illustrate that it is beneficial to develop potential targets for a new generation of new pharmaceutical therapies that would alleviate testicular dysfunctions. BTB: blood-testis barrier; DD: death domains; DR3: death receptor 3; DR4: death receptor 4; DR5: death receptor 5; DED: death effector domain; DISC: death-inducing signaling complex; ERα: estrogen receptor alpha; FADD: Fas-associated death domain; FSH: follicle- stimulating hormone; IL-1β: interleukin 1 beta; LH: luteinizing hormone; LPS: lipopolysaccharide; mFas: membrane Fas; MMP2: matrix metalloproteinase-2; MTA1: metastasis-associated protein 1; NAC: N-acetylcysteine; NCCD: the Nomenclature Committee on Cell Death; NFAT: nuclear factor of activated T-cells; NF-kB: nuclear transcription factor-kappaB; NO: nitric oxide; NP: 4-nonylphenol; PCD: programmed cell death; PP1/PP2A: protein phosphatase 1 and 2A; ROS: reactive oxygen species; sFas: soluble Fas; T: testosterone; TGF-β: transforming growth factor-beta; THD: TNF homology domain; TIMP-2: tissue inhibitor of metalloproteinase-2; TNF: tumor necrosis factor; TNF-α: tumor necrosis factor-alpha; TNF-R1: Tumor necrosis factor receptor 1; TNFRSF1A: TNF receptor superfamily member 1A.

Two signaling molecules share a phosphotyrosine-containing binding site in the platelet-derived growth factor receptor.

PubMed

Nishimura, R; Li, W; Kashishian, A; Mondino, A; Zhou, M; Cooper, J; Schlessinger, J

1993-11-01

Autophosphorylation sites of growth factor receptors with tyrosine kinase activity function as specific binding sites for Src homology 2 (SH2) domains of signaling molecules. This interaction appears to be a crucial step in a mechanism by which receptor tyrosine kinases relay signals to downstream signaling pathways. Nck is a widely expressed protein consisting exclusively of SH2 and SH3 domains, the overexpression of which causes cell transformation. It has been shown that various growth factors stimulate the phosphorylation of Nck and its association with autophosphorylated growth factor receptors. A panel of platelet-derived growth factor (PDGF) receptor mutations at tyrosine residues has been used to identify the Nck binding site. Here we show that mutation at Tyr-751 of the PDGF beta-receptor eliminates Nck binding both in vitro and in living cells. Moreover, the Y751F PDGF receptor mutant failed to mediate PDGF-stimulated phosphorylation of Nck in intact cells. A phosphorylated Tyr-751 is also required for binding of phosphatidylinositol-3 kinase to the PDGF receptor. Hence, the SH2 domains of p85 and Nck share a binding site in the PDGF receptor. Competition experiments with different phosphopeptides derived from the PDGF receptor suggest that binding of Nck and p85 is influenced by different residues around Tyr-751. Thus, a single tyrosine autophosphorylation site is able to link the PDGF receptor to two distinct SH2 domain-containing signaling molecules.

Peroxisome proliferator-activated receptor (PPAR)-gamma expression in human vascular smooth muscle cells: inhibition of growth, migration, and c-fos expression by the peroxisome proliferator-activated receptor (PPAR)-gamma activator troglitazone.

PubMed

Benson, S; Wu, J; Padmanabhan, S; Kurtz, T W; Pershadsingh, H A

2000-01-01

This study was conducted to determine whether cultured human coronary artery and aorta vascular smooth muscle (VSM) cells express the nuclear transcription factor peroxisome proliferator-activated receptor-gamma (PPARgamma); whether the thiazolidinedione troglitazone, a ligand for PPARgamma, would inhibit c-fos expression by these cells; and whether troglitazone would inhibit proliferation and migration induced in these cells by mitogenic growth factors. Using immunoblotting and reverse-transcriptase polymerase chain reaction (RT-PCR) techniques, we show that both human aorta and coronary artery VSM cell lines expressed PPARgamma protein and mRNA for both PPARgamma isoforms, PPARgamma1 and PPARgamma2. Immunocytochemical staining localized the PPARgamma protein primarily within the nucleus. Troglitazone inhibited basic fibroblast growth factor and platelet-derived growth factor-BB induced DNA synthesis in a dose-dependent manner and downregulated the growth-factor-induced expression of c-fos. Troglitazone also inhibited the migration of coronary artery VSM cells along a platelet-derived growth factor-BB concentration gradient. These findings demonstrate for the first time the expression and nuclear localization of PPARgamma in human coronary artery and aorta VSM cells. The data also suggest that the downregulation of c-fos expression, growth-factor-induced proliferation, and migration by VSM may, in part, be mediated by activation of the PPARgamma receptor.

Membrane receptor location defines receptor interaction with signaling proteins in a polarized epithelium.

PubMed

Amsler, K; Kuwada, S K

1999-01-01

Signal transduction from receptors is mediated by the interaction of activated receptors with proximate downstream signaling proteins. In polarized epithelial cells, the membrane is divided into subdomains: the apical and basolateral membranes. Membrane receptors may be present in one or both subdomains. Using a combination of immunoprecipitation and Western blot analyses, we tested the hypothesis that a tyrosine kinase growth factor receptor, epidermal growth factor receptor (EGFR), interacts with distinct signaling proteins when present at the apical vs. basolateral membrane of a polarized renal epithelial cell. We report here that tyrosine phosphorylation of phospholipase C-gamma (PLC-gamma) was induced only when basolateral EGFR was activated. In contrast, tyrosine phosphorylation of several other signaling proteins was increased by activation of receptor at either surface. All signaling proteins were distributed diffusely throughout the cytoplasm; however, PLC-gamma protein also displayed a concentration at lateral cell borders. These results demonstrate that in polarized epithelial cells the array of signaling pathways initiated by activation of a membrane receptor is defined, at least in part, by the membrane location of the receptor.

Bradykinin-induced growth inhibition of normal rat kidney (NRK) cells is paralleled by a decrease in epidermal-growth-factor receptor expression.

PubMed Central

Van Zoelen, E J; Peters, P H; Afink, G B; Van Genesen, S; De Roos, D G; Van Rotterdam, W; Theuvenet, A P

1994-01-01

Normal rat kidney fibroblasts, grown to density arrest in the presence of epidermal growth factor (EGF), can be induced to undergo phenotypic transformation by treatment with transforming growth factor beta or retinoic acid. Here we show that bradykinin blocks this growth-stimulus-induced loss of density-dependent growth arrest by a specific receptor-mediated mechanism. The effects of bradykinin are specific, and are not mimicked by other phosphoinositide-mobilizing agents such as prostaglandin F2 alpha. Northern-blot analysis and receptor-binding studies demonstrate that bradykinin also inhibits the retinoic acid-induced increase in EGF receptor levels in these cells. These studies provide additional evidence that EGF receptor levels modulate EGF-induced expression of the transformed phenotype in these cells. Images Figure 5 PMID:8135739

Mouse glucocorticoid-induced tumor necrosis factor receptor ligand is costimulatory for T cells

PubMed Central

Tone, Masahide; Tone, Yukiko; Adams, Elizabeth; Yates, Stephen F.; Frewin, Mark R.; Cobbold, Stephen P.; Waldmann, Herman

2003-01-01

Recently, agonist antibodies to glucocorticoid-induced tumor necrosis factor receptor (GITR) (tumor necrosis factor receptor superfamily 18) have been shown to neutralize the suppressive activity of CD4+CD25+ regulatory T cells. It was anticipated that this would be the role of the physiological ligand. We have identified and expressed the gene for mouse GITR ligand and have confirmed that its interaction with GITR reverses suppression by CD4+CD25+ T cells. It also, however, provides a costimulatory signal for the antigen-driven proliferation of naïve T cells and polarized T helper 1 and T helper 2 clones. RT-PCR and mAb staining revealed mouse GITR ligand expression in dendritic cells, macrophages, and B cells. Expression was controlled by the transcription factor NF-1 and potentially by alternative splicing of mRNA destabilization sequences. PMID:14608036

Activation of BAD by therapeutic inhibition of epidermal growth factor receptor and transactivation by insulin-like growth factor receptor.

PubMed

Gilmore, Andrew P; Valentijn, Anthony J; Wang, Pengbo; Ranger, Ann M; Bundred, Nigel; O'Hare, Michael J; Wakeling, Alan; Korsmeyer, Stanley J; Streuli, Charles H

2002-08-02

Novel cancer chemotherapeutics are required to induce apoptosis by activating pro-apoptotic proteins. Both epidermal growth factor (EGF) and insulin-like growth factor (IGF) provide potent survival stimuli in many epithelia, and activation of their receptors is commonly observed in solid human tumors. Here we demonstrate that blockade of the EGF receptor by a new drug in phase III clinical trails for cancer, ZD1839, potently induces apoptosis in mammary epithelial cell lines and primary cultures, as well as in a primary pleural effusion from a breast cancer patient. We identified the mechanism of apoptosis induction by ZD1839. We showed that it prevents cell survival by activating the pro-apoptotic protein BAD. Moreover, we demonstrate that IGF transactivates the EGF receptor and that ZD1839 blocks IGF-mediated phosphorylation of MAPK and BAD. Many cancer therapies kill tumor cells by inducing apoptosis as a consequence of targeting DNA; however, the threshold at which apoptosis can be triggered through DNA damage is often different from that in normal cells. Our results indicate that by targeting a growth factor-mediated survival signaling pathway, BAD phosphorylation can be manipulated therapeutically to induce apoptosis.

NMDA receptor mediates proliferation and CREB phosphorylation in postnatal Müller glia-derived retinal progenitors

PubMed Central

Ramírez, Mónica

2009-01-01

Purpose Postnatal retinal Müller glia are considered to be retinal progenitors as they retain the ability to dedifferentiate, proliferate, and differentiate to new retinal glia and neurons after injury. The proliferation and differentiation processes are coordinated by several extrinsic factors and neurotransmitters, including glutamate. Thus, the appropriate numbers and proportions of the different cell types are generated to form a functional retina during development and during injury repair. Here we analyze the changes in the proliferation of postnatal Müller glia-derived progenitors after activation of the N-methyl-D-aspartate (NMDA) glutamate receptors. Methods Müller glia-derived progenitor cell cultures were characterized by immunocytochemistry with antibodies against the NR1 subunit of the NMDA receptor and the progenitor cell marker nestin. The effect of glutamate receptor agonists and antagonists on cell proliferation was analyzed by BrdU incorporation or Ki67 immunostaining, cell counting, and by immunolabeling of phosphorylated cAMP response element binding protein (P-CREB) transcription factor. The effect of NMDA receptor activation was analyzed in vivo by P-CREB immunohistochemistry in retinal sections of Long-Evans NMDA injected rats. Results We show that NMDA receptor activation significantly increases the proliferation rate of Müller-glia derived progenitor cells and that this increase can be blocked by NMDA receptor antagonists. Furthermore, we show that CREB phosphorylation is induced in NMDA-treated Müller-glia derived progenitor cells in culture and that specific pharmacological inhibition of CREB phosphorylation results in a decreased number of proliferating cells. We confirmed the relevance of these observations by the analysis of retinal sections after NMDA injection in vivo where immunoreactivity to phosphorylated CREB is also increased after treatment. Conclusions In the present study we show that NMDA receptor activation induces postnatal Müller glia-derived retinal cell progenitor proliferation and transcription factor CREB phosphorylation both in culture and in vivo. The identification of the molecular determinants of mature retinal progenitors such as transcription factor CREB and NMDA receptor-induced players should facilitate the control of growth and manipulation of progenitor cell cultures and the possible identification of the molecular mechanisms involved in progenitor self-renewal. PMID:19365572

Combination therapy of potential gene to enhance oral cancer therapeutic effect

NASA Astrophysics Data System (ADS)

Yeh, Chia-Hsien; Hsu, Yih-Chih

2015-03-01

The epidermal growth factor receptor (EGFR) over-regulation related to uncontrolled cell division and promotes progression in tumor. Over-expression of human epidermal growth factor receptor (EGFR) has been detected in oral cancer cells. EGFR-targeting agents are potential therapeutic modalities for treating oral cancer based on our in vitro study. Liposome nanotechnology is used to encapsulate siRNA and were modified with target ligand to receptors on the surface of tumor cells. We used EGFR siRNA to treat oral cancer in vitro.

Decoupling the Functional Pleiotropy of Stem Cell Factor by Tuning c-Kit Signaling

PubMed Central

Ho, Chia Chi M.; Chhabra, Akanksha; Starkl, Philipp; Schnorr, Peter-John; Wilmes, Stephan; Moraga, Ignacio; Kwon, Hye-Sook; Gaudenzio, Nicolas; Sibilano, Riccardo; Wehrman, Tom S.; Gakovic, Milica; Sockolosky, Jonathan T.; Tiffany, Matthew R.; Ring, Aaron M.; Piehler, Jacob; Weissman, Irving L.; Galli, Stephen J.; Shizuru, Judith A.; Garcia, K. Christopher

2017-01-01

SUMMARY Most secreted growth factors and cytokines are functionally pleiotropic because their receptors are expressed on diverse cell types. While important for normal mammalian physiology, pleiotropy limits the efficacy of cytokines and growth factors as therapeutics. Stem cell factor (SCF) is a growth factor that acts through the c-Kit receptor tyrosine kinase to elicit hematopoietic progenitor expansion, but can be toxic when administered in vivo because it concurrently activates mast cells. We engineered a mechanism-based SCF partial agonist that impaired c-Kit dimerization, truncating downstream signaling amplitude. This SCF variant elicited biased activation of hematopoietic progenitors over mast cells in vitro and in vivo. Mouse models of SCF-mediated anaphylaxis, radioprotection, and hematopoietic expansion revealed that this SCF partial agonist retained therapeutic efficacy while exhibiting virtually no anaphylactic off-target effects. The approach of biasing cell activation by tuning signaling thresholds and outputs has applications to many dimeric receptor-ligand systems. PMID:28283060

Peptide hormones and lung cancer.

PubMed

Moody, T W

2006-03-01

Several peptide hormones have been identified which alter the proliferation of lung cancer. Small cell lung cancer (SCLC), which is a neuroendocrine cancer, produces and secretes gastrin releasing peptide (GRP), neurotensin (NT) and adrenomedullin (AM) as autocrine growth factors. GRP, NT and AM bind to G-protein coupled receptors causing phosphatidylinositol turnover or elevated cAMP in SCLC cells. Addition of GRP, NT or AM to SCLC cells causes altered expression of nuclear oncogenes, such as c-fos, and stimulation of growth. Antagonists have been developed for GRP, NT and AM receptors which function as cytostatic agents and inhibit SCLC growth. Growth factor antagonists, such as the NT1 receptor antagonist SR48692, facilitate the ability of chemotherapeutic drugs to kill lung cancer cells. It remains to be determined if GRP, NT and AM receptors will served as molecular targets, for development of new therapies for the treatment of SCLC patients. Non-small cell lung cancer (NSCLC) cells also have a high density of GRP, NT, AM and epidermal growth factor (EGF) receptors. Several NSCLC patients with EGF receptor mutations respond to gefitinib, a tyrosine kinase inhibitor. Gefitinib relieves NSCLC symptoms, maintaining stable disease in patients who are not eligible for systemic chemotherapy. It is important to develop new therapeutic approaches using translational research techniques for the treatment of lung cancer patients.

STK-1, the human homolog of Flk-2/Flt-3, is selectively expressed in CD34+ human bone marrow cells and is involved in the proliferation of early progenitor/stem cells.

PubMed Central

Small, D; Levenstein, M; Kim, E; Carow, C; Amin, S; Rockwell, P; Witte, L; Burrow, C; Ratajczak, M Z; Gewirtz, A M

1994-01-01

We cloned the cDNA for stem cell tyrosine kinase 1 (STK-1), the human homolog of murine Flk-2/Flt-3, from a CD34+ hematopoietic stem cell-enriched library and investigated its expression in subsets of normal human bone marrow. The cDNA encodes a protein of 993 aa with 85% identity and 92% similarity to Flk-2/Flt-3. STK-1 is a member of the type III receptor tyrosine kinase family that includes KIT (steel factor receptor), FMS (colony-stimulating factor 1R), and platelet-derived growth factor receptor. STK-1 expression in human blood and marrow is restricted to CD34+ cells, a population greatly enriched for stem/progenitor cells. Anti-STK-1 antiserum recognizes polypeptides of 160 and 130 kDa in several STK-1-expressing cell lines and in 3T3 cells transfected with a STK-1 expression vector. Antisense oligonucleotides directed against STK-1 sequences inhibited hematopoietic colony formation, most strongly in long-term bone marrow cultures. These data suggest that STK-1 may function as a growth factor receptor on hematopoietic stem and/or progenitor cells. Images Fig. 2 Fig. 3 Fig. 4 PMID:7507245

N-Cadherin and Fibroblast Growth Factor Receptors crosstalk in the control of developmental and cancer cell migrations.

PubMed

Nguyen, Thao; Mège, René Marc

2016-11-01

Cell migrations are diverse. They constitutemajor morphogenetic driving forces during embryogenesis, but they contribute also to the loss of tissue homeostasis and cancer growth. Capabilities of cells to migrate as single cells or as collectives are controlled by internal and external signalling, leading to the reorganisation of their cytoskeleton as well as by the rebalancing of cell-matrix and cell-cell adhesions. Among the genes altered in numerous cancers, cadherins and growth factor receptors are of particular interest for cell migration regulation. In particular, cadherins such as N-cadherin and a class of growth factor receptors, namely FGFRs cooperate to regulate embryonic and cancer cell behaviours. In this review, we discuss on reciprocal crosstalk between N-cadherin and FGFRs during cell migration. Finally, we aim at clarifying the synergy between N-cadherin and FGFR signalling that ensure cellular reorganization during cell movements, mainly during cancer cell migration and metastasis but also during developmental processes. Copyright © 2016 Elsevier GmbH. All rights reserved.

Identification of a nonsense mutation in the granulocyte-colony-stimulating factor receptor in severe congenital neutropenia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, F.; Loewenberg, B.; Hoefsloot, L.H.

Severe congenital neutropenia (Kostmann syndrome) is characterized by profound absolute neutropenia and a maturation arrest of marrow progenitor cells at the promyelocyte-myelocyte stage. Marrow cells from such patients frequently display a reduced responsiveness to granulocyte-colony-stimulating factor (G-CSF). G-CSF binds to and activates a specific receptor which transduces signals critical for the proliferation and maturation of granulocytic progenitor cells. Here the authors report the identification of a somatic point mutation in one allele of the G-CSF receptor gene in a patient with severe congenital neutropenia. The mutation results in a cytoplasmic truncation of the receptor. When expressed in murine myeloid cells,more » the mutant receptor transduced a strong growth signal but, in contrast to the wild-type G-CSF receptor, was defective in maturation induction. This mutant receptor chain may act in a dominant negative manner to block granulocytic maturation. 40 refs., figs., 2 tabs.« less

Phosphorylation of hepatocyte growth factor receptor and epidermal growth factor receptor of human hepatocytes can be maintained in a (3D) collagen sandwich culture system.

PubMed

Engl, Tobias; Boost, Kim A; Leckel, Kerstin; Beecken, Wolf-Dietrich; Jonas, Dietger; Oppermann, Elsie; Auth, Marcus K H; Schaudt, André; Bechstein, Wolf-Otto; Blaheta, Roman A

2004-08-01

In vitro culture models that employ human liver cells could be potent tools for predictive studies on drug toxicity and metabolism in the pharmaceutical industry. However, an adequate receptor responsiveness is necessary to allow intracellular signalling and metabolic activity. We tested the ability of three-dimensionally arranged human hepatocytes to respond to the growth factors hepatocyte growth factor (HGF) or epidermal growth factor (EGF). Isolated adult human hepatocytes were cultivated within a three-dimensional collagen gel (sandwich) or on a two-dimensional collagen matrix. Cells were treated with HGF or EGF and expression and phosphorylative activity of HGF receptors (HGFr, c-met) or EGF receptors (EGFr) were measured by flow cytometry and Western blot. Increasing HGFr and EGFr levels were detected in hepatocytes growing two-dimensionally. However, both receptors were not activated in presence of growth factors. In contrast, when hepatocytes were plated within a three-dimensional matrix, HGFr and EGFr levels remained constantly low. However, both receptors became strongly phosphorylated by soluble HGF or EGF. We conclude that cultivation of human hepatocytes in a three-dimensionally arranged in vitro system allows the maintenance of specific functional activities. The necessity of cell dimensionality for HGFr and EGFr function should be considered when an adequate in vitro system has to be introduced for drug testing.

Expression of a functional epidermal growth factor receptor on human adipose-derived mesenchymal stem cells and its signaling mechanism.

PubMed

Baer, Patrick C; Schubert, Ralf; Bereiter-Hahn, Jürgen; Plösser, Michaela; Geiger, Helmut

2009-05-01

Adult stem cells act as a pluripotent source of regenerative cells during tissue injury. Despite expanded research in stem cell biology, understanding how growth and migration of adipose-derived adult mesenchymal stem cells (ASC) are governed by interactions with growth factors is very limited. One important property of ASC is the presence of the epidermal growth factor (EGF) receptor and the cellular response to soluble EGF. Expression of the EGF receptor was proven by PCR and Western blotting. Signal transduction was analyzed by Western blotting and PhosFlow assay. EGF caused robust phosphorylation of SHC and ERK1/2, which could be inhibited by EGF receptor antagonist AG1478 and MEK inhibitor PD98059. ASC proliferation was determined by MTT assay. Stem cell migration was analyzed in a modified Boyden chamber. Incubation with EGF led to cell proliferation and induced cell migration, but did not change the undifferentiated state of the cells. In the kidney, injured renal tubular cells express high amounts of EGF. Therefore, our results may highlight a mechanism underlying renal regeneration. Thus, future in vivo studies that focus on the effects of EGF on recruitment of ASC to sites of injury are necessary.

Recent Advances in Molecular Mechanisms of Taste Signaling and Modifying.

PubMed

Shigemura, Noriatsu; Ninomiya, Yuzo

2016-01-01

The sense of taste conveys crucial information about the quality and nutritional value of foods before it is ingested. Taste signaling begins with taste cells via taste receptors in oral cavity. Activation of these receptors drives the transduction systems in taste receptor cells. Then particular transmitters are released from the taste cells and activate corresponding afferent gustatory nerve fibers. Recent studies have revealed that taste sensitivities are defined by distinct taste receptors and modulated by endogenous humoral factors in a specific group of taste cells. Such peripheral taste generations and modifications would directly influence intake of nutritive substances. This review will highlight current understanding of molecular mechanisms for taste reception, signal transduction in taste bud cells, transmission between taste cells and nerves, regeneration from taste stem cells, and modification by humoral factors at peripheral taste organs. Copyright © 2016 Elsevier Inc. All rights reserved.

Gene Transfer and Molecular Cloning of the Human NGF Receptor

NASA Astrophysics Data System (ADS)

Chao, Moses V.; Bothwell, Mark A.; Ross, Alonzo H.; Koprowski, Hilary; Lanahan, Anthony A.; Buck, C. Randall; Sehgal, Amita

1986-04-01

Nerve growth factor (NGF) and its receptor are important in the development of cells derived from the neural crest. Mouse L cell transformants have been generated that stably express the human NGF receptor gene transfer with total human DNA. Affinity cross-linking, metabolic labeling and immunoprecipitation, and equilibrium binding with 125I-labeled NGF revealed that this NGF receptor had the same size and binding characteristics as the receptor from human melanoma cells and rat PC12 cells. The sequences encoding the NGF receptor were molecularly cloned using the human Alu repetitive sequence as a probe. A cosmid clone that contained the human NGF receptor gene allowed efficient transfection and expression of the receptor.

Specific growth stimulation of cultured smooth muscle cells from spontaneously hypertensive rats by platelet-derived growth factor A-chain homodimer.

PubMed Central

Resink, T J; Scott-Burden, T; Hahn, A W; Rouge, M; Hosang, M; Powell, J S; Bühler, F R

1990-01-01

Cultured vascular smooth muscle cells (VSMC)1 from spontaneously hypertensive rats (SHR) possess specific cell surface receptors for both homodimeric forms of platelet-derived growth factor (PDGF-AA and PDGF-BB), in contrast to cells from normotensive Wistar Kyoto (WKY) animals, which express receptors only for the B-chain form of PDGF. Stimulation of quiescent VSMC from SHR with PDGF-AA resulted in activation of S6-kinase and induction of phosphoinositide catabolism, as well as cellular proliferation when cultures were maintained for prolonged periods with daily supplementation of the growth factor. WKY-derived VSMC showed no response to PDGF-AA, which was consistent with their lack of specific receptors for this homodimer. The responsiveness of quiescent cells from SHR and WKY to the B-chain homodimer was similar. The enhanced growth responsiveness of SHR-derived cells to fetal calf serum, as compared with cells from their normotensive counterparts, may be accounted for in part by their expression of receptors for the AA homodimer of PDGF. PMID:1965150

Sch proteins are localized on endoplasmic reticulum membranes and are redistributed after tyrosine kinase receptor activation.

PubMed Central

Lotti, L V; Lanfrancone, L; Migliaccio, E; Zompetta, C; Pelicci, G; Salcini, A E; Falini, B; Pelicci, P G; Torrisi, M R

1996-01-01

The intracellular localization of Shc proteins was analyzed by immunofluorescence and immunoelectron microscopy in normal cells and cells expressing the epidermal growth factor receptor or the EGFR/erbB2 chimera. In unstimulated cells, the immunolabeling was localized in the central perinuclear area of the cell and mostly associated with the cytosolic side of rough endoplasmic reticulum membranes. Upon epidermal growth factor treatment and receptor tyrosine kinase activation, the immunolabeling became peripheral and was found to be associated with the cytosolic surface of the plasma membrane and endocytic structures, such as coated pits and endosomes, and with the peripheral cytosol. Receptor activation in cells expressing phosphorylation-defective mutants of Shc and erbB-2 kinase showed that receptor autophosphorylation, but not Shc phosphorylation, is required for redistribution of Shc proteins. The rough endoplasmic reticulum localization of Shc proteins in unstimulated cells and their massive recruitment to the plasma membrane, endocytic structures, and peripheral cytosol following receptor tyrosine kinase activation could account for multiple putative functions of the adaptor protein. PMID:8628261

T-cell receptor signaling activates an ITK/NF-κB/GATA-3 axis in T-cell lymphomas facilitating resistance to chemotherapy

PubMed Central

Wang, Tianjiao; Lu, Ye; Polk, Avery; Chowdhury, Pinki; Zamalloa, Carlos Murga; Fujiwara, Hiroshi; Suemori, Koichiro; Beyersdorf, Niklas; Hristov, Alexandra C.; Lim, Megan S.; Bailey, Nathanael G.; Wilcox, Ryan A.

2016-01-01

Purpose T-cell lymphomas are a molecularly heterogeneous group of non-Hodgkin lymphomas (NHL) that account for a disproportionate number of NHL disease-related deaths due to their inherent and acquired resistance to standard multiagent chemotherapy regimens. Despite their molecular heterogeneity and frequent loss of various T-cell specific receptors, the T-cell antigen receptor is retained in the majority of these lymphomas. As T-cell receptor (TCR) engagement activates a number of signaling pathways and transcription factors that regulate T-cell growth and survival, we examined the TCR’s role in mediating resistance to chemotherapy. Experimental Design Genetic and pharmacologic strategies were utilized to determine the contribution of tyrosine kinases and transcription factors activated in conventional T cells following T-cell receptor (TCR) engagement in acquired chemotherapy resistance in primary T-cell lymphoma cells and patient-derived cell lines. Results Here we report that TCR signaling activates a signaling axis that includes ITK, NF-κB, and GATA-3, and promotes chemotherapy resistance. Conclusions These observations have significant therapeutic implications, as pharmacologic inhibition of ITK prevented activation of this signaling axis and overcame chemotherapy resistance. PMID:27780854

Phenytoin enhances the phosphorylation of epidermal growth factor receptor and fibroblast growth factor receptor in the subventricular zone and promotes the proliferation of neural precursor cells and oligodendrocyte differentiation.

PubMed

Galvez-Contreras, Alma Y; Gonzalez-Castaneda, Rocio E; Campos-Ordonez, Tania; Luquin, Sonia; Gonzalez-Perez, Oscar

2016-01-01

Phenytoin is a widely used antiepileptic drug that induces cell proliferation in several tissues, such as heart, bone, skin, oral mucosa and neural precursors. Some of these effects are mediated via fibroblast growth factor receptor (FGFR) and epidermal growth factor receptor (EGFR). These receptors are strongly expressed in the adult ventricular-subventricular zone (V-SVZ), the main neurogenic niche in the adult brain. The aim of this study was to determine the cell lineage and cell fate of V-SVZ neural progenitors expanded by phenytoin, as well as the effects of this drug on EGFR/FGFR phosphorylation. Male BALB/C mice received 10 mg/kg phenytoin by oral cannula for 30 days. We analysed the proliferation of V-SVZ neural progenitors by immunohistochemistry and western blot. Our findings indicate that phenytoin enhanced twofold the phosphorylation of EGFR and FGFR in the V-SVZ, increased the number of bromodeoxyuridine (BrdU)+/Sox2+ and BrdU+/doublecortin+ cells in the V-SVZ, and expanded the population of Olig2-expressing cells around the lateral ventricles. After phenytoin removal, a large number of BrdU+/Receptor interacting protein (RIP)+ cells were observed in the olfactory bulb. In conclusion, phenytoin enhanced the phosphorylation of FGFR and EGFR, and promoted the expression of neural precursor markers in the V-SVZ. In parallel, the number of oligodendrocytes increased significantly after phenytoin removal. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Correlation between erythropoietin receptor(s) and estrogen and progesterone receptor expression in different breast cancer cell lines.

PubMed

Trošt, Nina; Hevir, Neli; Rižner, Tea Lanišnik; Debeljak, Nataša

2013-03-01

Erythropoietin (EPO) receptor (EPOR) expression in breast cancer has been shown to correlate with the expression of estrogen receptor (ESR) and progesterone receptor (PGR) and to be associated with the response to tamoxifen in ESR+/PGR+ tumors but not in ESR- tumors. In addition, the correlation between EPOR and G protein-coupled estrogen receptor 1 [GPER; also known as G protein-coupled receptor 30 (GPR30)] has been reported, suggesting the prognostic potential of EPOR expression. Moreover, the involvement of colony stimulating factor 2 receptor, β, low‑affinity (CSF2RB) and ephrin type-B receptor 4 (EPHB4) as EPOR potential receptor partners in cancer has been indicated. This study analyzed the correlation between the expression of genes for EPO, EPOR, CSF2RB, EPHB4, ESR, PGR and GPER in the MCF-7, MDA-MB-361, T-47D, MDA-MB-231, Hs578Bst, SKBR3, MCF-10A and Hs578T cell lines. The cell lines were also treated with recombinant human EPO (rHuEPO) in order to determine its ability to activate the Jak/STAT5, MAPK and PI3K signaling pathways and modify cell growth characteristics. Expression analysis stratified the cell lines in 2 main clusters, hormone-dependent cell lines expressing ESR and PGR and a hormone-independent cluster. A significant correlation was observed between the expression levels of ESR and PGR and their expression was also associated with that of GPER. Furthermore, the expression of GPER was associated with that of EPOR, suggesting the connection between this orphan G protein and EPO signaling. A negative correlation between EPOR and CSF2RB expression was observed, questioning the involvement of these two receptors in the hetero-receptor formation. rHuEPO treatment only influenced the hormone-independent cell lines, since only the MDA-MB-231, SKBR3 and Hs578T cells responded to the treatment. The correlation between the expression of the analyzed receptors suggests that the receptors may interact in order to activate signaling pathways or to evade their inhibition. Therefore, breast cancer classification upon ESR, PGR and human epidermal growth factor receptor 2 (HER2) may not be sufficient for the selection of suitable treatment protocol. The expression of EPOR, GPER and EPHB4 may be considered as additional classification factors.

Chimeric antigen receptor T cells: a novel therapy for solid tumors.

PubMed

Yu, Shengnan; Li, Anping; Liu, Qian; Li, Tengfei; Yuan, Xun; Han, Xinwei; Wu, Kongming

2017-03-29

The chimeric antigen receptor T (CAR-T) cell therapy is a newly developed adoptive antitumor treatment. Theoretically, CAR-T cells can specifically localize and eliminate tumor cells by interacting with the tumor-associated antigens (TAAs) expressing on tumor cell surface. Current studies demonstrated that various TAAs could act as target antigens for CAR-T cells, for instance, the type III variant epidermal growth factor receptor (EGFRvIII) was considered as an ideal target for its aberrant expression on the cell surface of several tumor types. CAR-T cell therapy has achieved gratifying breakthrough in hematological malignancies and promising outcome in solid tumor as showed in various clinical trials. The third generation of CAR-T demonstrates increased antitumor cytotoxicity and persistence through modification of CAR structure. In this review, we summarized the preclinical and clinical progress of CAR-T cells targeting EGFR, human epidermal growth factor receptor 2 (HER2), and mesothelin (MSLN), as well as the challenges for CAR-T cell therapy.

Impact of morphine on the expression of insulin receptor and protein levels of insulin/IGFs in rat neural stem cells.

PubMed

Salarinasab, Sadegh; Nourazarian, AliReza; Nikanfar, Masoud; Abdyazdani, Nima; Kazemi, Masoumeh; Feizy, Navid; Rahbarghazi, Reza

2017-11-01

Alzheimer's disease is correlated with neuronal degeneration and loss of neuronal precursors in different parts of the brain. It has been found disturbance in the homeostasis neural stem cells (NSCs) can cause neurodegeneration. Morphine, an analgesic agent, can disrupt the dynamic and normal state of NSCs. However, more investigations are required to clearly address underlying mechanisms. The current experiment aimed to investigate the effects of morphine on the cell distribution of insulin factor and receptor and insulin-like growth factors (IGF1, IGF2) in NSCs. NSCs were isolated from rats and stemness feature confirmed by antibodies against nestin and Sox2. The cells were exposed to 100μM morphine, 50μM naloxone and combination of these two drugs for 72h. The neural cell growth, changes in levels of insulin and insulin-like growth factors secreted by NSCs as well as the insulin-receptor-gene expression were assessed by flow cytometry, ELlSA, and real-time PCR, respectively. Cell cycle assay revealed the exposure of cells to morphine for 72h increased cell apoptosis and decreased neural stem cell growth. The biosynthesis of insulin, insulin-like growth factors, and insulin receptor were reduced (p<0.05) after NSCs exposure to morphine at the concentration of 100μM for 24, 48 and 72h. Naloxone is a competitive antagonist which binds MOR where morphine (and endogenous opioids) bind, and reversed the detrimental effects of morphine. It can be concluded that morphine initiated irregularity in NSCs kinetics and activity by reducing the secretion of insulin and insulin-like growth factors and down-regulation of insulin receptor. Copyright © 2017 Elsevier B.V. All rights reserved.

Posttraumatic Propofol Neurotoxicity Is Mediated via the Pro-Brain-Derived Neurotrophic Factor-p75 Neurotrophin Receptor Pathway in Adult Mice.

PubMed

Sebastiani, Anne; Granold, Matthias; Ditter, Anja; Sebastiani, Philipp; Gölz, Christina; Pöttker, Bruno; Luh, Clara; Schaible, Eva-Verena; Radyushkin, Konstantin; Timaru-Kast, Ralph; Werner, Christian; Schäfer, Michael K; Engelhard, Kristin; Moosmann, Bernd; Thal, Serge C

2016-02-01

The gamma-aminobutyric acid modulator propofol induces neuronal cell death in healthy immature brains by unbalancing neurotrophin homeostasis via p75 neurotrophin receptor signaling. In adulthood, p75 neurotrophin receptor becomes down-regulated and propofol loses its neurotoxic effect. However, acute brain lesions, such as traumatic brain injury, reactivate developmental-like programs and increase p75 neurotrophin receptor expression, probably to foster reparative processes, which in turn could render the brain sensitive to propofol-mediated neurotoxicity. This study investigates the influence of delayed single-bolus propofol applications at the peak of p75 neurotrophin receptor expression after experimental traumatic brain injury in adult mice. Randomized laboratory animal study. University research laboratory. Adult C57BL/6N and nerve growth factor receptor-deficient mice. Sedation by IV propofol bolus application delayed after controlled cortical impact injury. Propofol sedation at 24 hours after traumatic brain injury increased lesion volume, enhanced calpain-induced αII-spectrin cleavage, and increased cell death in perilesional tissue. Thirty-day postinjury motor function determined by CatWalk (Noldus Information Technology, Wageningen, The Netherlands) gait analysis was significantly impaired in propofol-sedated animals. Propofol enhanced pro-brain-derived neurotrophic factor/brain-derived neurotrophic factor ratio, which aggravates p75 neurotrophin receptor-mediated cell death. Propofol toxicity was abolished both by pharmacologic inhibition of the cell death domain of the p75 neurotrophin receptor (TAT-Pep5) and in mice lacking the extracellular neurotrophin binding site of p75 neurotrophin receptor. This study provides first evidence that propofol sedation after acute brain lesions can have a deleterious impact and implicates a role for the pro-brain-derived neurotrophic factor-p75 neurotrophin receptor pathway. This observation is important as sedation with propofol and other compounds with GABA receptor activity are frequently used in patients with acute brain pathologies to facilitate sedation or surgical and interventional procedures.

Roles of cell-cell adhesion-dependent tyrosine phosphorylation of Gab-1.

PubMed

Shinohara, M; Kodama, A; Matozaki, T; Fukuhara, A; Tachibana, K; Nakanishi, H; Takai, Y

2001-06-01

Gab-1 is a multiple docking protein that is tyrosine phosphorylated by receptor tyrosine kinases such as c-Met, hepatocyte growth factor/scatter factor receptor, and epidermal growth factor receptor. We have now demonstrated that cell-cell adhesion also induces marked tyrosine phosphorylation of Gab-1 and that disruption of cell-cell adhesion results in its dephosphorylation. An anti-E-cadherin antibody decreased cell-cell adhesion-dependent tyrosine phosphorylation of Gab-1, whereas the expression of E-cadherin specifically induced tyrosine phosphorylation of Gab-1. A relatively selective inhibitor of Src family kinases reduced cell-cell adhesion-dependent tyrosine phosphorylation of Gab-1, whereas expression of a dominant-negative mutant of Csk increased it. Disruption of cell-cell adhesion, which reduced tyrosine phosphorylation of Gab-1, also reduced the activation of mitogen-activated protein kinase and Akt in response to cell-cell adhesion. These results indicate that E-cadherin-mediated cell-cell adhesion induces tyrosine phosphorylation by a Src family kinase of Gab-1, thereby regulating the activation of Ras/MAP kinase and phosphatidylinositol 3-kinase/Akt cascades.

Cell surface control of the multiubiquitination and deubiquitination of high-affinity immunoglobulin E receptors.

PubMed Central

Paolini, R; Kinet, J P

1993-01-01

Multiubiquitination of proteins is a critical step leading to selective degradation for many polypeptides. Therefore, activation-induced multiubiquitination of cell surface receptors, such as the platelet-derived growth factor (PDGF) receptor and the T cell antigen (TCR) receptor, may correspond to a degradation pathway for ligand-receptor complexes. Here we show that the antigen-induced engagement of high-affinity immunoglobulin E receptors (Fc epsilon RI) results in the immediate multiubiquitination of Fc epsilon RI beta and gamma chains. This ubiquitination is independent of receptor phosphorylation and is restricted to activated receptors. Surprisingly, receptor multiubiquitination is immediately reversible when receptors are disengaged. Therefore, multiubiquitination and deubiquitination of Fc epsilon RI receptors is controlled at the cell surface by receptor engagement and disengagement. The rapidity, specificity and, most importantly, the reversibility of the activation-induced receptor multiubiquitination suggest that this process may turn on/off a cell surface receptor signaling function thus far unsuspected. Images PMID:8382611

Regulation of gonadotropin receptors on cultured porcine Leydig and Sertoli cells: effect of potassium depletion.

PubMed

Bernier, M; Laferrere, B; Jaillard, C; Clerget, M; Saez, J M

1986-06-01

We have examined the role of the NaK-ATPase pump activity on the ligand-induced down-regulation of gonadotropin receptors in cultured porcine Leydig and Sertoli cells. In both cells, inhibition of the NaK pump by ouabain produced a depletion of intracellular K+ levels (ID50, 10(-7) M) after a lag period of about 8 h. In the absence of ligand, the number of FSH receptors in ouabain-treated Sertoli cells was unaffected or slightly reduced, whereas a 2-fold increase in the number of human CG (hCG)/LH receptors with small changes in the binding affinity was observed in Leydig cells treated by ouabain. The effect of ouabain was dose dependent. Differences were also observed in the down-regulation process of gonadotropin receptors in ouabain-treated cells. The hCG-induced receptor loss in Leydig cells was completely reversed by ouabain whereas the drug had no effect on ligand-induced loss of FSH receptors in Sertoli cells. Similar results were observed when the cells were incubated in K+-free medium. Kinetics studies with labeled hCG have shown that ouabain treatment slows down significantly the rate of [125I]iodo-hCG internalization (t 1/2, 18 h; control cells, t 1/2, 6 h), but had no effect on the degradation of internalized hormone. The internalization of receptor-bound [125I]iodo-hCG was also reduced when Leydig cells were incubated in K+-free medium, but was restored when this medium was supplemented with rubidium. The influence of the NaK pump on the receptor regulation of a ligand common to both types of cells, such as epidermal growth factor, was studied under the same experimental conditions. Neither ouabain nor K+-free medium were able to prevent the epidermal growth factor-induced reduction of receptor levels in Leydig and Sertoli cells. Thus, it appears that modulation of ligand-induced receptor loss by depletion of cellular K+ levels is not dependent on the cell type, but on the ligand-receptor complex. The data also show a striking difference in the dynamics of gonadotropin-receptor interaction of two structurally related hormones.

Prostaglandin E₂ regulates cellular migration via induction of vascular endothelial growth factor receptor-1 in HCA-7 human colon cancer cells.

PubMed

Fujino, Hiromichi; Toyomura, Kaori; Chen, Xiao-bo; Regan, John W; Murayama, Toshihiko

2011-02-01

An important event in the development of tumors is angiogenesis, or the formation of new blood vessels. Angiogenesis is also known to be involved in tumor cell metastasis and is dependent upon the activity of the vascular endothelial growth factor (VEGF) signaling pathway. Studies of mice in which the EP3 prostanoid receptors have been genetically deleted have shown a role for these receptors in cancer growth and angiogenesis. In the present study, human colon cancer HCA-7 cells were used as a model system to understand the potential role of EP3 receptors in tumor cell migration. We now show that stimulation of HCA-7 cells with PGE₂ enhanced the up-regulation of VEGF receptor-1 (VEGFR-1) expression by a mechanism involving EP3 receptor-mediated activation of phosphatidylinositol 3-kinase and the extracellular signal-regulated kinases. Moreover, the PGE₂ stimulated increase in VEGFR-1 expression was accompanied by an increase in the cellular migration of HCA-7 cells. Given the known involvement of VEGFR-1 in cellular migration, our results suggest that EP3 receptors may contribute to tumor cell metastasis by increasing cellular migration through the up-regulation of VEGFR-1 signaling. Copyright © 2010 Elsevier Inc. All rights reserved.

The overexpressed human 46-kDa mannose 6-phosphate receptor mediates endocytosis and sorting of. beta. -glucuronidase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watanabe, H.; Grubb, J.H.; Sly, W.S.

1990-10-01

The authors studied the function of the human small (46-kDa) mannose 6-phosphate receptor (SMPR) in transfected mouse L cells that do not express the larger insulin-like growth factor II/mannose 6-phosphate receptor. Cells overexpressing human SMPR were studied for enzyme binding to cell surface receptors, for binding to intracellular receptors in permeabilized cells, and for receptor-mediated endocytosis of recombinant human {beta}-glucuronidase. Specific binding to human SMPR in permeabilized cells showed a pH optimum between pH 6.0 and pH 6.5. Binding was significant in the present of EDTA but was enhanced by added divalent cations. Up to 2.3{percent} of the total functionalmore » receptor could be detected on the cell surface by enzyme binding. They present experiments showing that at very high levels of overexpression, and at pH 6.5, human SMPR mediated the endocytosis of {beta}-glucuronidase. At pH 7.5, the rate of endocytosis was only 14{percent} the rate seen at pH 6.5. Cells overexpressing human SMPR also showed reduced secretion of newly synthesized {beta}-glucuronidase when compared to cells transfected with vector only, suggesting that overexpressed human SMPR can participate in sorting of newly synthesized {beta}-glucuronidase and partially correct the sorting defect in mouse L cells that do not express the insulin-like growth factor II/mannose 6-phosphate receptor.« less

Significance of increased expression of decoy receptor 3 in chronic liver disease.

PubMed

Kim, S; Kotoula, V; Hytiroglou, P; Zardavas, D; Zhang, L

2009-08-01

Considerable evidence has indicated that apoptosis plays an important role in hepatocyte death in chronic liver disease. However, the cellular and molecular mechanisms underlying liver regeneration in these diseases are largely unknown. Plausibly, certain molecules expressed to counteract apoptosis might provide survival advantage of certain liver cells. Therefore, we investigated a possible expression of decoy receptor 3 of the tumour necrosis factor receptor family in chronic liver diseases since decoy receptor 3 is known to inhibit apoptosis mediated by pro-apoptotic tumour necrosis factor family ligands including Fas ligand. A series of liver biopsies from patients with different stages of fibrosis were subjected to immunohistochemistry and in situ hybridization. Both decoy receptor 3 protein and mRNA were mainly expressed in biliary epithelial cells and infiltrating lymphocytes in the diseased livers. Most noticeably, intense decoy receptor 3 expression was observed in newly developing biliary ductules in regenerative nodules as well as dysplastic nodules of cirrhotic livers. In addition, decoy receptor 3 secretion in hepatocellular carcinoma cells in culture was via the activation of mitogen-activated protein kinases. Decoy receptor 3 was specifically expressed in chronic liver diseases and hepatocellular carcinoma cells, and decoy receptor 3 might facilitate the survival of liver cells by exerting its anti-apoptotic activity during the progression of liver cirrhosis and hepatocarcinogenesis.

Effects of heparin-binding epidermal growth factor-like growth factor on cell repopulation and signal transduction in periodontal ligament cells after scratch wounding in vitro.

PubMed

Lee, J S; Kim, J M; Hong, E K; Kim, S-O; Yoo, Y-J; Cha, J-H

2009-02-01

A growing amount of attention has been placed on periodontal regeneration and wound healing for periodontal therapy. This study was conducted in an effort to determine the effects of heparin-binding epidermal growth factor-like growth factor on cell repopulation and signal transduction in periodontal ligament cells after scratch wounding in vitro. Human periodontal ligament cells were acquired from explant tissue of human healthy periodontal ligament. After the wounding of periodontal ligament cells, the change in expression of heparin-binding epidermal growth factor-like growth factor and epidermal growth factor receptors 1-4 mRNA was assessed. The effects of heparin-binding epidermal growth factor-like growth factor on periodontal ligament cell proliferation and repopulation were assessed in vitro via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and by photographing the injuries, respectively. Extracellular signal-regulated kinase (Erk)1/2, p38 and Akt phosphorylation was characterized via western blotting. Scratch wounding resulted in a significant up-regulation of heparin-binding epidermal growth factor-like growth factor mRNA expression, whereas wounding had no effect on the expression levels of epidermal growth factor receptors 1-4. Interestingly, no expression of epidermal growth factor receptors 2 and 4 was detectable prior to or after wounding. Heparin-binding epidermal growth factor-like growth factor treatment promoted the proliferation and repopulation of periodontal ligament cells. The scratch wounding also stimulated the phosphorylation of Erk1/2 and p38, but not of Akt, in periodontal ligament cells, and heparin-binding epidermal growth factor-like growth factor treatment applied after wounding amplified and extended the activations of Erk1/2 and p38, but not of Akt. Furthermore, Erk1/2 inhibition blocked the process of cell repopulation induced by heparin-binding epidermal growth factor-like growth factor, whereas the inhibition of p38 delayed the process. These results indicate that heparin-binding epidermal growth factor-like growth factor may constitute a critical factor in the wound healing of human periodontal ligament cells by a mechanism that requires the activation of Erk1/2 via specific interaction with epidermal growth factor receptor 1.

ErbB2 and EGFR are downmodulated during the differentiation of 3T3-L1 preadipocytes.

PubMed

Pagano, Eleonora; Calvo, Juan Carlos

2003-10-15

The expression of receptors belonging to the epidermal growth factor receptor subfamily has been largely studied these last years in epithelial cells mainly as involved in cell proliferation and malignant progression. Although much work has focused on the role of these growth factor receptors in the differentiation of a variety of tissues, there is little information in regards to normal stromal cells. We investigated erbB2 expression in the murine fibroblast cell line Swiss 3T3L1, which naturally or hormonally induced undergoes adipocyte differentiation. We found that the Swiss 3T3-L1 fibroblasts express erbB2, in addition to EGFR, and in a quantity comparable to or even greater than the breast cancer cell line T47D. Proliferating cells increased erbB2 and EGFR levels when reaching confluence up to 4- and 10-fold, respectively. This expression showed a significant decrease when growth-arrested cells were stimulated to differentiate with dexamethasone and isobutyl-methylxanthine. Differentiated cells presented a decreased expression of both erbB2 and EGFR regardless of whether the cells were hormonally or spontaneously differentiated. EGF stimulation of serum-starved cells increased erbB2 tyrosine phosphorylation and retarded erbB2 migration in SDS-PAGE, suggesting receptor association and activation. Heregulin-alpha1 and -beta1, two EGF related factors, had no effect on erbB2 or EGFR phosphorylation. Although 3T3-L1 cells expressed heregulin, its specific receptors, erbB3 and erbB4, were not found. This is the first time in which erbB2 is reported to be expressed in an adipocytic cell line which does not depend on non EGF family growth factors (thyroid hormone, growth hormone, etc.) to accomplish adipose differentiation. Since erbB2 and EGFR expression were downmodulated as differentiation progressed it is conceivable that a mechanism of switching from a mitogenic to a differentiating signaling pathway may be involved, through regulation of the expression of these growth factor receptors. Copyright 2003 Wiley-Liss, Inc.

Role of Stat3 and ErbB2 in Breast Cancer

DTIC Science & Technology

2012-10-01

also activated by receptor tyrosine kinases, such as the epidermal growth factor receptor (EGFR) or platelet -derived growth factor receptor (PDGFR...cells were grown to different densities, up to 5 days post-confluence, as indicated. Detergent cell lysates were probed for Stat3-ptyr705, active Rac...and lysates probed for total cav1, cadherin 11 or tubulin as a loading control. 15 C Figure 7: Cadherin 11 and Rac1 downregulation

Expression of receptors for putative anabolic growth factors in human intervertebral disc: implications for repair and regeneration of the disc.

PubMed

Le Maitre, Christine L; Richardson, Stephen M A; Baird, Pauline; Freemont, Anthony J; Hoyland, Judith A

2005-12-01

Low back pain (LBP) is a common, debilitating and economically important disorder. Current evidence implicates loss of intervertebral disc (IVD) matrix consequent upon 'degeneration' as a major cause of LBP. Degeneration of the IVD involves increases in degradative enzymes and decreases in the extracellular matrix (ECM) component in a process that is controlled by a range of cytokines and growth factors. Studies have suggested using anabolic growth factors to regenerate the normal matrix of the IVD, hence restoring disc height and reversing degenerative disc disease. However, for such therapies to be successful it is vital that the target cells (i.e. the disc cells) express the appropriate receptors. This immunohistochemical study has for the first time investigated the expression and localization of four potentially beneficial growth factor receptors (i.e. TGFbetaRII, BMPRII, FGFR3 and IGFRI) in non-degenerate and degenerate human IVDs. Receptor expression was quantified across regions of the normal and degenerate disc and showed that cells of the nucleus pulposus (NP) and inner annulus fibrosus (IAF) expressed significantly higher levels of the four growth factor receptors investigated. There were no significant differences between the four growth factor expression in non-degenerate and degenerate biopsies. However, expression of TGFbetaRII, FGFR3 and IGFRI, but not BMP RII, were observed in the ingrowing blood vessels that characterize part of the disease aetiology. In conclusion, this study has demonstrated the expression of the four growth factor receptors at similar levels in the chondrocyte-like cells of the NP and IAF in both non-degenerate and degenerate discs, implicating a role in normal disc homeostasis and suggesting that the application of these growth factors to the degenerate human IVD would stimulate matrix production. However, the expression of some of the growth factor receptors on ingrowing blood vessels might be problematic in a therapeutic approach. Copyright 2005 Pathological Society of Great Britain and Ireland.

Transforming Growth Factor-B Receptors in Human Breast Cancer.

DTIC Science & Technology

1998-05-01

I., Polyak, K., Iavarone, A., and Massagud, J. Kip/ Cip and Ink4 cdk inhibitors cooperate to induce cell cycle arrest in response to TGF-ß. Genes Dev...specimens. Thirdly, we have developped transient transfection assays to determine how specific TßR mutations affect affect receptor function. Using...Growth Factor-ß (TGFß) is the most potent known inhibitor of cell cycle progression of normal mammary epithelial cells; in addition, it causes cells

Factor X/Xa elicits protective signaling responses in endothelial cells directly via PAR-2 and indirectly via endothelial protein C receptor-dependent recruitment of PAR-1.

PubMed

Bae, Jong-Sup; Yang, Likui; Rezaie, Alireza R

2010-11-05

We recently demonstrated that the Gla domain-dependent interaction of protein C with endothelial protein C receptor (EPCR) leads to dissociation of the receptor from caveolin-1 and recruitment of PAR-1 to a protective signaling pathway. Thus, the activation of PAR-1 by either thrombin or PAR-1 agonist peptide elicited a barrier-protective response if endothelial cells were preincubated with protein C. In this study, we examined whether other vitamin K-dependent coagulation protease zymogens can modulate PAR-dependent signaling responses in endothelial cells. We discovered that the activation of both PAR-1 and PAR-2 in endothelial cells pretreated with factor FX (FX)-S195A, but not other procoagulant protease zymogens, also results in initiation of protective intracellular responses. Interestingly, similar to protein C, FX interaction with endothelial cells leads to dissociation of EPCR from caveolin-1 and recruitment of PAR-1 to a protective pathway. Further studies revealed that, FX activated by factor VIIa on tissue factor bearing endothelial cells also initiates protective signaling responses through the activation of PAR-2 independent of EPCR mobilization. All results could be recapitulated by the receptor agonist peptides to both PAR-1 and PAR-2. These results suggest that a cross-talk between EPCR and an unknown FX/FXa receptor, which does not require interaction with the Gla domain of FX, recruits PAR-1 to protective signaling pathways in endothelial cells.

The TAM-family receptor Mer mediates production of HGF through the RhoA-dependent pathway in response to apoptotic cells.

PubMed

Park, Hyun-Jung; Baen, Ji-Yeon; Lee, Ye-Ji; Choi, Youn-Hee; Kang, Jihee Lee

2012-08-01

The TAM receptor protein tyrosine kinases Tyro3, Axl, and Mer play important roles in macrophage function. We investigated the roles of the TAM receptors in mediating the induction of hepatocyte growth factor (HGF) during the interaction of macrophages with apoptotic cells. Mer-specific neutralizing antibody, small interfering RNA (siRNA), and a recombinant Mer protein (Mer/Fc) inhibited HGF mRNA and protein expression, as well as activation of RhoA, Akt, and specific mitogen-activated protein (MAP) kinases in response to apoptotic cells. Inhibition of Axl or Tyro3 with specific antibodies, siRNA, or Fc-fusion proteins did not prevent apoptotic cell-induced HGF mRNA and protein expression and did not inhibit activation of the postreceptor signaling molecules RhoA and certain MAP kinases, including extracellular signal-regulated protein kinase and c-Jun NH(2)-terminal kinase. However, Axl- and Tyro3-specific blockers did inhibit the activation of Akt and p38 MAP kinase in response to apoptotic cells. In addition, none of the TAM receptors mediated the effects of apoptotic cells on transforming growth factor-β or epidermal growth factor mRNA expression. However, they were involved in the induction of vascular endothelial growth factor mRNA expression. Our data provide evidence that when macrophages interact with apoptotic cells, only Mer of the TAM-family receptors is responsible for mediating transcriptional HGF production through a RhoA-dependent pathway.

Autologous Bone Marrow Stromal Cells Genetically Engineered to Secrete an IGF-I Receptor Decoy Prevent the Growth of Liver Metastases

PubMed Central

Wang, Ni; Fallavollita, Lucia; Nguyen, Long; Burnier, Julia; Rafei, Moutih; Galipeau, Jacques; Yakar, Shoshana; Brodt, Pnina

2009-01-01

Liver metastases respond poorly to current therapy and remain a frequent cause of cancer-related mortality. We reported previously that tumor cells expressing a soluble form of the insulin-like growth factor-I receptor (sIGFIR) lost the ability to metastasize to the liver. Here, we sought to develop a novel therapeutic approach for prevention of hepatic metastasis based on sustained in vivo delivery of the soluble receptor by genetically engineered autologous bone marrow stromal cells. We found that when implanted into mice, these cells secreted high plasma levels of sIGFIR and inhibited experimental hepatic metastases of colon and lung carcinoma cells. In hepatic micrometastases, a reduction in intralesional angiogenesis and increased tumor cell apoptosis were observed. The results show that the soluble receptor acted as a decoy to abort insulin-like growth factor-I receptor (IGF-IR) functions during the early stages of metastasis and identify sustained sIGFIR delivery by cell-based vehicles as a potential approach for prevention of hepatic metastasis. PMID:19367255

The opposing roles of laminin-binding integrins in cancer.

PubMed

Ramovs, Veronika; Te Molder, Lisa; Sonnenberg, Arnoud

2017-01-01

Integrins play an important role in cell adhesion by linking the cytoskeleton of cells to components in the extracellular matrix. In this capacity, integrins cooperate with different cell surface receptors, including growth factor receptors and G-protein coupled receptors, to regulate intracellular signaling pathways that control cell polarization, spreading, migration, survival, and gene expression. A distinct subfamily of molecules in the integrin family of adhesion receptors is formed by receptors that mediate cell adhesion to laminins, major components of the basement membrane that lie under clusters of cells or surround them, separating them from other cells and/or adjacent connective tissue. During the past decades, many studies have provided evidence for a role of laminin-binding integrins in tumorigenesis, and both tumor-promoting and suppressive activities have been identified. In this review we discuss the dual role of the laminin-binding integrins α3β1 and α6β4 in tumor development and progression, and examine the factors and mechanisms involved in these opposing effects. Copyright © 2016 Elsevier B.V. All rights reserved.

Muscarinic receptor agonists stimulate human colon cancer cell migration and invasion.

PubMed

Belo, Angelica; Cheng, Kunrong; Chahdi, Ahmed; Shant, Jasleen; Xie, Guofeng; Khurana, Sandeep; Raufman, Jean-Pierre

2011-05-01

Muscarinic receptors (CHRM) are overexpressed in colon cancer. To explore a role for muscarinic receptor signaling in colon cancer metastasis, we used human H508 and HT29 colon cancer cells that coexpress epidermal growth factor (ERBB) and CHRM3 receptors. In a wound closure model, following 8-h incubation of H508 cells with 100 μM ACh we observed a threefold increase in cell migration indistinguishable from the actions of epidermal growth factor (EGF). Atropine blocked the actions of ACh but not of EGF. In SNU-C4 colon cancer cells that express ERBB but not CHRM, EGF caused a threefold increase in migration; ACh had no effect. ACh-induced cell migration was attenuated by chemical inhibitors of ERBB1 activation, by anti-ERBB1 antibody, and by inhibitors of ERK and phosphatidylinositol 3-kinase (PI3K) signaling. Consistent with matrix metalloproteinase-7 (MMP7)-mediated release of an ERBB1 ligand, heparin binding epidermal growth factor-like growth factor (HBEGF), ACh-induced migration was inhibited by an MMP inhibitor and by anti-MMP7 and -HBEGF antibodies. ACh-induced cell migration was blocked by inhibiting RhoA and ROCK, key proteins that interact with the actin cytoskeleton. ACh-induced RhoA activation was attenuated by agents that inhibit ERBB1, ERK, and PI3K activation. Collectively, these findings indicate that ACh-induced cell migration is mediated by MMP7-mediated release of HBEGF, an ERBB ligand that activates ERBB1 and downstream ERK and PI3K signaling. In a cell invasion model, ACh-induced HT29 cell invasion was blocked by atropine. In concert with previous observations, these findings indicate that muscarinic receptor signaling plays a key role in colon cancer cell proliferation, survival, migration, and invasion.

Muscarinic receptor agonists stimulate human colon cancer cell migration and invasion

PubMed Central

Belo, Angelica; Cheng, Kunrong; Chahdi, Ahmed; Shant, Jasleen; Xie, Guofeng; Khurana, Sandeep

2011-01-01

Muscarinic receptors (CHRM) are overexpressed in colon cancer. To explore a role for muscarinic receptor signaling in colon cancer metastasis, we used human H508 and HT29 colon cancer cells that coexpress epidermal growth factor (ERBB) and CHRM3 receptors. In a wound closure model, following 8-h incubation of H508 cells with 100 μM ACh we observed a threefold increase in cell migration indistinguishable from the actions of epidermal growth factor (EGF). Atropine blocked the actions of ACh but not of EGF. In SNU-C4 colon cancer cells that express ERBB but not CHRM, EGF caused a threefold increase in migration; ACh had no effect. ACh-induced cell migration was attenuated by chemical inhibitors of ERBB1 activation, by anti-ERBB1 antibody, and by inhibitors of ERK and phosphatidylinositol 3-kinase (PI3K) signaling. Consistent with matrix metalloproteinase-7 (MMP7)-mediated release of an ERBB1 ligand, heparin binding epidermal growth factor-like growth factor (HBEGF), ACh-induced migration was inhibited by an MMP inhibitor and by anti-MMP7 and -HBEGF antibodies. ACh-induced cell migration was blocked by inhibiting RhoA and ROCK, key proteins that interact with the actin cytoskeleton. ACh-induced RhoA activation was attenuated by agents that inhibit ERBB1, ERK, and PI3K activation. Collectively, these findings indicate that ACh-induced cell migration is mediated by MMP7-mediated release of HBEGF, an ERBB ligand that activates ERBB1 and downstream ERK and PI3K signaling. In a cell invasion model, ACh-induced HT29 cell invasion was blocked by atropine. In concert with previous observations, these findings indicate that muscarinic receptor signaling plays a key role in colon cancer cell proliferation, survival, migration, and invasion. PMID:21273532

Filamin A Modulates Kinase Activation and Intracellular Trafficking of Epidermal Growth Factor Receptors in Human Melanoma Cells

PubMed Central

Fiori, Jennifer L.; Zhu, Tie-Nian; O'Connell, Michael P.; Hoek, Keith S.; Indig, Fred E.; Frank, Brittany P.; Morris, Christa; Kole, Sutapa; Hasskamp, Joanne; Elias, George; Weeraratna, Ashani T.; Bernier, Michel

2009-01-01

The actin-binding protein filamin A (FLNa) affects the intracellular trafficking of various classes of receptors and has a potential role in oncogenesis. However, it is unclear whether FLNa regulates the signaling capacity and/or down-regulation of the activated epidermal growth factor receptor (EGFR). Here it is shown that partial knockdown of FLNa gene expression blocked ligand-induced EGFR responses in metastatic human melanomas. To gain greater insights into the role of FLNa in EGFR activation and intracellular sorting, we used M2 melanoma cells that lack endogenous FLNa and a subclone in which human FLNa cDNA has been stably reintroduced (M2A7 cells). Both tyrosine phosphorylation and ubiquitination of EGFR were significantly lower in epidermal growth factor (EGF)-stimulated M2 cells when compared with M2A7 cells. Moreover, the lack of FLNa interfered with EGFR interaction with the ubiquitin ligase c-Cbl. M2 cells exhibited marked resistance to EGF-induced receptor degradation, which was very active in M2A7 cells. Despite comparable rates of EGF-mediated receptor endocytosis, internalized EGFR colocalized with the lysosomal marker lysosome-associated membrane protein-1 in M2A7 cells but not M2 cells, in which EGFR was found to be sequestered in large vesicles and subsequently accumulated in punctated perinuclear structures after EGF stimulation. These results suggest the requirement of FLNa for efficient EGFR kinase activation and the sorting of endocytosed receptors into the degradation pathway. PMID:19213840

Interleukin 6 inhibits proliferation and, in cooperation with an epidermal growth factor receptor autocrine loop, increases migration of T47D breast cancer cells.

PubMed

Badache, A; Hynes, N E

2001-01-01

Interleukin (IL)-6, a multifunctional regulator of immune response, hematopoiesis, and acute phase reactions, has also been shown to regulate cancer cell proliferation. We have investigated IL-6 signaling pathways and cellular responses in the T47D breast carcinoma cell line. The IL-6-type cytokines, IL-6 and oncostatin M, simultaneously inhibited cell proliferation and increased cell migration. In T47D cells, IL-6 stimulated the activation of Janus-activated kinase 1 tyrosine kinase and signal transducers and activators of transcription (STAT) 1 and STAT3 transcription factors. Expression of dominant negative STAT3 in the cells strongly reduced IL-6-mediated growth inhibition but did not prevent IL-6-induced cell migration. IL-6 treatment led to activation of the mitogen-activated protein kinase (MAPK) and the phosphatidylinositol 3'-kinase (PI3K) pathways. Inhibition of MAPK or PI3K activity reversed IL-6- and oncostatin M-stimulated migration. Because cross-talk between cytokine receptors and members of the ErbB family of receptor tyrosine kinases has been described previously, we have examined their interaction in T47D cells. Down-regulation of ErbB receptor activity, through the use of specific pharmacological inhibitors or dominant negative receptor constructs, revealed that IL-6-induced MAPK activation was largely dependent on epidermal growth factor (EGF) receptor activity, but not on ErbB-2 activity. Using a monoclonal antibody that interferes with EGF receptor-ligand interaction, we have shown that in T47D cells, IL-6 cooperates with an EGF receptor autocrine activity loop for signaling through the MAPK and PI3K pathways and for cell migration. Both the tyrosine phosphatase SHP-2 and the multisubstrate docking molecule Gab1, which are potential links between IL-6 and the MAPK/PI3K pathways, were constitutively associated with the active EGF receptor. On IL-6 stimulation, SHP-2 and Gab1 were recruited to the gp130 subunit of the IL-6 receptor and tyrosine phosphorylated, allowing downstream signaling to the MAPK and PI3K pathways. Thus, in T47D breast carcinoma cells, IL-6 acts in synergy with EGF receptor autocrine activity to signal through the MAPK/PI3K pathways. Cooperation between IL-6 and the EGF receptor in T47D breast carcinoma cells illustrates how a combination of multiple stimuli, either exogenous or endogenous, may result in synergistic cellular responses.

Self-renewal of human embryonic stem cells requires insulin-like growth factor-1 receptor and ERBB2 receptor signaling

PubMed Central

Wang, Linlin; Schulz, Thomas C.; Sherrer, Eric S.; Dauphin, Derek S.; Shin, Soojung; Nelson, Angelique M.; Ware, Carol B.; Zhan, Mei; Song, Chao-Zhong; Chen, Xiaoji; Brimble, Sandii N.; McLean, Amanda; Galeano, Maria J.; Uhl, Elizabeth W.; D'Amour, Kevin A.; Chesnut, Jonathan D.; Rao, Mahendra S.

2007-01-01

Despite progress in developing defined conditions for human embryonic stem cell (hESC) cultures, little is known about the cell-surface receptors that are activated under conditions supportive of hESC self-renewal. A simultaneous interrogation of 42 receptor tyrosine kinases (RTKs) in hESCs following stimulation with mouse embryonic fibroblast (MEF) conditioned medium (CM) revealed rapid and prominent tyrosine phosphorylation of insulin receptor (IR) and insulin-like growth factor-1 receptor (IGF1R); less prominent tyrosine phosphorylation of epidermal growth factor receptor (EGFR) family members, including ERBB2 and ERBB3; and trace phosphorylation of fibroblast growth factor receptors. Intense IGF1R and IR phosphorylation occurred in the absence of MEF conditioning (NCM) and was attributable to high concentrations of insulin in the proprietary KnockOut Serum Replacer (KSR). Inhibition of IGF1R using a blocking antibody or lentivirus-delivered shRNA reduced hESC self-renewal and promoted differentiation, while disruption of ERBB2 signaling with the selective inhibitor AG825 severely inhibited hESC proliferation and promoted apoptosis. A simple defined medium containing an IGF1 analog, heregulin-1β (a ligand for ERBB2/ERBB3), fibroblast growth factor-2 (FGF2), and activin A supported long-term growth of multiple hESC lines. These studies identify previously unappreciated RTKs that support hESC proliferation and self-renewal, and provide a rationally designed medium for the growth and maintenance of pluripotent hESCs. PMID:17761519

The cannabinoid receptor CB1 modulates the signaling properties of the lysophosphatidylinositol receptor GPR55.

PubMed

Kargl, Julia; Balenga, Nariman; Parzmair, Gerald P; Brown, Andrew J; Heinemann, Akos; Waldhoer, Maria

2012-12-28

The G protein-coupled receptor (GPCR) 55 (GPR55) and the cannabinoid receptor 1 (CB1R) are co-expressed in many tissues, predominantly in the central nervous system. Seven transmembrane spanning (7TM) receptors/GPCRs can form homo- and heteromers and initiate distinct signaling pathways. Recently, several synthetic CB1 receptor inverse agonists/antagonists, such as SR141716A, AM251, and AM281, were reported to activate GPR55. Of these, SR141716A was marketed as a promising anti-obesity drug, but was withdrawn from the market because of severe side effects. Here, we tested whether GPR55 and CB1 receptors are capable of (i) forming heteromers and (ii) whether such heteromers could exhibit novel signaling patterns. We show that GPR55 and CB1 receptors alter each others signaling properties in human embryonic kidney (HEK293) cells. We demonstrate that the co-expression of FLAG-CB1 receptors in cells stably expressing HA-GPR55 specifically inhibits GPR55-mediated transcription factor activation, such as nuclear factor of activated T-cells and serum response element, as well as extracellular signal-regulated kinases (ERK1/2) activation. GPR55 and CB1 receptors can form heteromers, but the internalization of both receptors is not affected. In addition, we observe that the presence of GPR55 enhances CB1R-mediated ERK1/2 and nuclear factor of activated T-cell activation. Our data provide the first evidence that GPR55 can form heteromers with another 7TM/GPCR and that this interaction with the CB1 receptor has functional consequences in vitro. The GPR55-CB1R heteromer may play an important physiological and/or pathophysiological role in tissues endogenously co-expressing both receptors.

The Cannabinoid Receptor CB1 Modulates the Signaling Properties of the Lysophosphatidylinositol Receptor GPR55*

PubMed Central

Kargl, Julia; Balenga, Nariman; Parzmair, Gerald P.; Brown, Andrew J.; Heinemann, Akos; Waldhoer, Maria

2012-01-01

The G protein-coupled receptor (GPCR) 55 (GPR55) and the cannabinoid receptor 1 (CB1R) are co-expressed in many tissues, predominantly in the central nervous system. Seven transmembrane spanning (7TM) receptors/GPCRs can form homo- and heteromers and initiate distinct signaling pathways. Recently, several synthetic CB1 receptor inverse agonists/antagonists, such as SR141716A, AM251, and AM281, were reported to activate GPR55. Of these, SR141716A was marketed as a promising anti-obesity drug, but was withdrawn from the market because of severe side effects. Here, we tested whether GPR55 and CB1 receptors are capable of (i) forming heteromers and (ii) whether such heteromers could exhibit novel signaling patterns. We show that GPR55 and CB1 receptors alter each others signaling properties in human embryonic kidney (HEK293) cells. We demonstrate that the co-expression of FLAG-CB1 receptors in cells stably expressing HA-GPR55 specifically inhibits GPR55-mediated transcription factor activation, such as nuclear factor of activated T-cells and serum response element, as well as extracellular signal-regulated kinases (ERK1/2) activation. GPR55 and CB1 receptors can form heteromers, but the internalization of both receptors is not affected. In addition, we observe that the presence of GPR55 enhances CB1R-mediated ERK1/2 and nuclear factor of activated T-cell activation. Our data provide the first evidence that GPR55 can form heteromers with another 7TM/GPCR and that this interaction with the CB1 receptor has functional consequences in vitro. The GPR55-CB1R heteromer may play an important physiological and/or pathophysiological role in tissues endogenously co-expressing both receptors. PMID:23161546

Fibroblast growth factor receptor signaling is essential for lens fiber cell differentiation.

PubMed

Zhao, Haotian; Yang, Tianyu; Madakashira, Bhavani P; Thiels, Cornelius A; Bechtle, Chad A; Garcia, Claudia M; Zhang, Huiming; Yu, Kai; Ornitz, David M; Beebe, David C; Robinson, Michael L

2008-06-15

The vertebrate lens provides an excellent model to study the mechanisms that regulate terminal differentiation. Although fibroblast growth factors (FGFs) are thought to be important for lens cell differentiation, it is unclear which FGF receptors mediate these processes during different stages of lens development. Deletion of three FGF receptors (Fgfr1-3) early in lens development demonstrated that expression of only a single allele of Fgfr2 or Fgfr3 was sufficient for grossly normal lens development, while mice possessing only a single Fgfr1 allele developed cataracts and microphthalmia. Profound defects were observed in lenses lacking all three Fgfrs. These included lack of fiber cell elongation, abnormal proliferation in prospective lens fiber cells, reduced expression of the cell cycle inhibitors p27(kip1) and p57(kip2), increased apoptosis and aberrant or reduced expression of Prox1, Pax6, c-Maf, E-cadherin and alpha-, beta- and gamma-crystallins. Therefore, while signaling by FGF receptors is essential for lens fiber differentiation, different FGF receptors function redundantly.

Expression of a transmembrane phosphotyrosine phosphatase inhibits cellular response to platelet-derived growth factor and insulin-like growth factor-1.

PubMed

Mooney, R A; Freund, G G; Way, B A; Bordwell, K L

1992-11-25

Tyrosine phosphorylation is a mechanism of signal transduction shared by many growth factor receptors and oncogene products. Phosphotyrosine phosphatases (PTPases) potentially modulate or counter-regulate these signaling pathways. To test this hypothesis, the transmembrane PTPase CD45 (leukocyte common antigen) was expressed in the murine cell line C127. Hormone-dependent autophosphorylation of the platelet-derived growth factor (PDGF) and insulin-like growth factor-1 (IGF-1) receptors was markedly reduced in cells expressing the transmembrane PTPase. Tyrosine phosphorylation of other PDGF-dependent phosphoproteins (160, 140, and 55 kDa) and IGF-1-dependent phosphoproteins (145 kDa) was similarly decreased. Interestingly, the pattern of growth factor-independent tyrosine phosphorylations was comparable in cells expressing the PTPase and control cells. This suggests a selectivity or accessibility of the PTPase limited to a subset of cellular phosphotyrosyl proteins. The maximum mitogenic response to PDGF and IGF-1 in cells expressing the PTPase was decreased by 67 and 71%, respectively. These results demonstrate that a transmembrane PTPase can both affect the tyrosine phosphorylation state of growth factor receptors and modulate proximal and distal cellular responses to the growth factors.

The C Terminus of the Saccharomyces cerevisiae α-Factor Receptor Contributes to the Formation of Preactivation Complexes with Its Cognate G Protein

PubMed Central

Dosil, Mercedes; Schandel, Kimberly A.; Gupta, Ekta; Jenness, Duane D.; Konopka, James B.

2000-01-01

Binding of the α-factor pheromone to its G-protein-coupled receptor (encoded by STE2) activates the mating pathway in MATa yeast cells. To investigate whether specific interactions between the receptor and the G protein occur prior to ligand binding, we analyzed dominant-negative mutant receptors that compete with wild-type receptors for G proteins, and we analyzed the ability of receptors to suppress the constitutive signaling activity of mutant Gα subunits in an α-factor-independent manner. Although the amino acid substitution L236H in the third intracellular loop of the receptor impairs G-protein activation, this substitution had no influence on the ability of the dominant-negative receptors to sequester G proteins or on the ability of receptors to suppress the GPA1-A345T mutant Gα subunit. In contrast, removal of the cytoplasmic C-terminal domain of the receptor eliminated both of these activities even though the C-terminal domain is unnecessary for G-protein activation. Moreover, the α-factor-independent signaling activity of ste2-P258L mutant receptors was inhibited by the coexpression of wild-type receptors but not by coexpression of truncated receptors lacking the C-terminal domain. Deletion analysis suggested that the distal half of the C-terminal domain is critical for sequestration of G proteins. The C-terminal domain was also found to influence the affinity of the receptor for α-factor in cells lacking G proteins. These results suggest that the C-terminal cytoplasmic domain of the α-factor receptor, in addition to its role in receptor downregulation, promotes the formation of receptor–G-protein preactivation complexes. PMID:10866688

An Antagonistic Vascular Endothelial Growth Factor (VEGF) Variant Inhibits VEGF-Stimulated Receptor Autophosphorylation and Proliferation of Human Endothelial Cells

NASA Astrophysics Data System (ADS)

Siemeister, Gerhard; Schirner, Michael; Reusch, Petra; Barleon, Bernhard; Marme, Dieter; Martiny-Baron, Georg

1998-04-01

Vascular endothelial growth factor (VEGF) is a potent mitogen with a unique specificity for endothelial cells and a key mediator of aberrant endothelial cell proliferation and vascular permeability in a variety of human pathological situations, such as tumor angiogenesis, diabetic retinopathy, rheumatoid arthritis, or psoriasis. VEGF is a symmetric homodimeric molecule with two receptor binding interfaces lying on each pole of the molecule. Herein we report on the construction and recombinant expression of an asymmetric heterodimeric VEGF variant with an intact receptor binding interface at one pole and a mutant receptor binding interface at the second pole of the dimer. This VEGF variant binds to VEGF receptors but fails to induce receptor activation. In competition experiments, the heterodimeric VEGF variant antagonizes VEGF-stimulated receptor autophosphorylation and proliferation of endothelial cells. A 15-fold excess of the heterodimer was sufficient to inhibit VEGF-stimulated endothelial cell proliferation by 50%, and a 100-fold excess resulted in an almost complete inhibition. By using a rational approach that is based on the structure of VEGF, we have shown the feasibility to construct a VEGF variant that acts as an VEGF antagonist.

Taci Is a Traf-Interacting Receptor for Tall-1, a Tumor Necrosis Factor Family Member Involved in B Cell Regulation

PubMed Central

Xia, Xing-Zhong; Treanor, James; Senaldi, Giorgio; Khare, Sanjay D.; Boone, Tom; Kelley, Michael; Theill, Lars E.; Colombero, Anne; Solovyev, Irina; Lee, Frances; McCabe, Susan; Elliott, Robin; Miner, Kent; Hawkins, Nessa; Guo, Jane; Stolina, Marina; Yu, Gang; Wang, Judy; Delaney, John; Meng, Shi-Yuan; Boyle, William J.; Hsu, Hailing

2000-01-01

We and others recently reported tumor necrosis factor (TNF) and apoptosis ligand–related leukocyte-expressed ligand 1 (TALL-1) as a novel member of the TNF ligand family that is functionally involved in B cell proliferation. Transgenic mice overexpressing TALL-1 have severe B cell hyperplasia and lupus-like autoimmune disease. Here, we describe expression cloning of a cell surface receptor for TALL-1 from a human Burkitt's lymphoma RAJI cell library. The cloned receptor is identical to the previously reported TNF receptor (TNFR) homologue transmembrane activator and calcium modulator and cyclophilin ligand (CAML) interactor (TACI). Murine TACI was subsequently isolated from the mouse B lymphoma A20 cells. Human and murine TACI share 54% identity overall. Human TACI exhibits high binding affinities to both human and murine TALL-1. Soluble TACI extracellular domain protein specifically blocks TALL-1–mediated B cell proliferation without affecting CD40- or lipopolysaccharide-mediated B cell proliferation in vitro. In addition, when injected into mice, soluble TACI inhibits antibody production to both T cell–dependent and –independent antigens. By yeast two-hybrid screening of a B cell library with TACI intracellular domain, we identified that, like many other TNFR family members, TACI intracellular domain interacts with TNFR-associated factor (TRAF)2, 5, and 6. Correspondingly, TACI activation in a B cell line results in nuclear factor κB and c-Jun NH2-terminal kinase activation. The identification and characterization of the receptor for TALL-1 provides useful information for the development of a treatment for B cell–mediated autoimmune diseases such as systemic lupus erythematosus. PMID:10880535

Angiotensin II type 1 receptor blockers prevent tumor necrosis factor-alpha-mediated endothelial nitric oxide synthase reduction and superoxide production in human umbilical vein endothelial cells.

PubMed

Kataoka, Hiroki; Murakami, Ryuichiro; Numaguchi, Yasushi; Okumura, Kenji; Murohara, Toyoaki

2010-06-25

Decrease in endothelial nitric oxide synthase (eNOS) expression is one of the adverse outcomes of endothelial dysfunction. Tumor necrosis factor-alpha (TNF-alpha) is known to decrease eNOS expression and is an important mediator of endothelial dysfunction. We hypothesized that an angiotensin II type 1 (AT1) receptor blocker would improve endothelial function via not only inhibition of the angiotensin II signaling but also inhibition of the TNF-alpha-mediated signaling. Therefore we investigated whether an AT1 receptor blocker would restore the TNF-alpha-induced decrease in eNOS expression in cultured human umbilical vein endothelial cells (HUVEC). Pretreatment of HUVEC with an antioxidant (superoxide dismutase, alpha-tocopherol) or AT1 receptor blockers (olmesartan or candesartan) restored the TNF-alpha-dependent reduction of eNOS. The AT1 receptor blocker decreased the TNF-alpha-dependent increase of 8-isoprostane. The superoxide dismutase activities in HUVEC were stable during AT1 receptor blocker treatment, and the AT1 receptor blocker did not scavenge superoxide directly. The AT1 receptor blocker also decreased TNF-alpha-induced phosphorylation of I kappaB alpha and cell death. These results suggest that AT1 receptor blockers are able to ameliorate TNF-alpha-dependent eNOS reduction or cell injury by inhibiting superoxide production or nuclear factor-kappaB activation. (c) 2010 Elsevier B.V. All rights reserved.

Mutant with diphtheria toxin receptor and acidification function but defective in entry of toxin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kohno, Kenji; Hayes, H.; Mekada, Eisuke

1987-09-01

A mutant of Chinese hamster ovary cells, GE1, that is highly resistant to diphtheria toxin was isolated. The mutant contains 50% ADP-ribosylatable elongation factor 2, but its protein synthesis was not inhibited by the toxin even at concentrations above 100 {mu}g/ml. {sup 125}I-labeled diphtheria toxin was associated with GE1 cells as well as with the parent cells but did not block protein synthesis of GE1 cells even when the cells were exposed to low pH in the presence or absence of NH{sub 4}Cl. The infections of GE1 cells and the parent cells by vesicular stomatitis virus were similar. GE1 cellsmore » were cross-resistant to Pseudomonas aeruginosa exotoxin A and so were about 1,000 times more resistant to this toxin than the parent cells. Hybrids of GE1 cells and the parent cells or mutant cells lacking a functional receptor were more sensitive to diphtheria toxin than GE1 cells. These results suggest that entry of diphtheria toxin into cells requires a cellular factor(s) in addition to those involved in receptor function and acidification of endosomes and that GE1 cells do not express this cellular factor. This character is recessive in GE1 cells.« less

Expression of Inapproptriate Cadherins in Human Breast Carcinomas

DTIC Science & Technology

2000-08-01

fibroblast growth factor receptor signaling. * We showed that cadherin 11 acts in a manner... fibroblast growth factor receptor signaling; and that cadherin 11 promotes epithelial cell motility in a manner similar to N-cadherin. 28 N-Cadherin...levels of E-cadherin; and that N- cadherin-dependent motility may be mediated by fibroblast growth factor receptor signaling. 14. SUBJECT TERMS

Nicotinic receptor-dependent and -independent effects of galantamine, an acetylcholinesterase inhibitor, on the non-neuronal acetylcholine system in C2C12 cells.

PubMed

Oikawa, Shino; Mano, Asuka; Iketani, Mitsue; Kakinuma, Yoshihiko

2015-11-01

We previously reported that satellite cells possess the ability to produce angiogenic factors, including fibroblast growth factor (FGF)-2 and vascular endothelial growth factor (VEGF) in vivo. However, whether C2C12 cells possess a non-neuronal cholinergic system (NNCS) or non-neuronal ACh (NNA) remains to be studied; therefore, we investigated the system using C2C12 cells and its regulatory mechanisms. C2C12 cells synthesized ACh, the level of which was comparable with that of cardiomyocytes, and the synthesis was augmented by the acetylcholinesterase inhibitor galantamine. The ChAT promoter activity was upregulated by nicotine or galantamine, partly through nicotinic receptors for both agents as well as through a non-nicotinic receptor pathway for galantamine. Further, VEGF secretion by C2C12 cells was also increased by nicotine or galantamine through nicotinic receptors as well as partly through non-nicotinic pathways in the case of galantamine. These results suggest that C2C12 cells are equipped with NNCS or NNA, which is positively regulated through nicotinic or non-nicotinic pathways, particularly in the case of galantamine. These results provide a novel concept that myogenic cells expressing NNA can be a therapeutic target for regulating angiogenic factor synthesis. Copyright © 2015 Elsevier B.V. All rights reserved.

Differential roles of vascular endothelial growth factor receptors 1 and 2 in dendritic cell differentiation.

PubMed

Dikov, Mikhail M; Ohm, Joyce E; Ray, Neelanjan; Tchekneva, Elena E; Burlison, Jared; Moghanaki, Drew; Nadaf, Sorena; Carbone, David P

2005-01-01

Impaired Ag-presenting function in dendritic cells (DCs) due to abnormal differentiation is an important mechanism of tumor escape from immune control. A major role for vascular endothelial growth factor (VEGF) and its receptors, VEGFR1/Flt-1 and VEGFR2/KDR/Flk-1, has been documented in hemopoietic development. To study the roles of each of these receptors in DC differentiation, we used an in vitro system of myeloid DC differentiation from murine embryonic stem cells. Exposure of wild-type, VEGFR1(-/-), or VEGFR2(-/-) embryonic stem cells to exogenous VEGF or the VEGFR1-specific ligand, placental growth factor, revealed distinct roles of VEGF receptors. VEGFR1 is the primary mediator of the VEGF inhibition of DC maturation, whereas VEGFR2 tyrosine kinase signaling is essential for early hemopoietic differentiation, but only marginally affects final DC maturation. SU5416, a VEGF receptor tyrosine kinase inhibitor, only partially rescued the mature DC phenotype in the presence of VEGF, suggesting the involvement of both tyrosine kinase-dependent and independent inhibitory mechanisms. VEGFR1 signaling was sufficient for blocking NF-kappaB activation in bone marrow hemopoietic progenitor cells. VEGF and placental growth factor affect the early stages of myeloid/DC differentiation. The data suggest that therapeutic strategies attempting to reverse the immunosuppressive effects of VEGF in cancer patients might be more effective if they specifically targeted VEGFR1.

Interplay between TGF-β signaling and receptor tyrosine kinases in tumor development.

PubMed

Shi, Qiaoni; Chen, Ye-Guang

2017-10-01

Transforming growth factor-β (TGF-β) signaling regulates cell proliferation, differentiation, migration and death, and plays a critical role in embryogenesis and tissue homeostasis. Its deregulation results in various diseases including tumor formation. Receptor tyrosine kinases (RTKs), such as epidermal growth factor receptor (EGFR), fibroblast growth factor receptor (FGFR), vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR), also play key roles in the development and progression of many types of tumors. It has been realized that TGF-β signaling and RTK pathways interact with each other and their interplay is important for cancer development. They are mutually regulated and cooperatively modulate cell survival and migration, epithelial-mesenchymal transition, and tumor microenvironment to accelerate tumorigenesis and tumor metastasis. RTKs can modulate Smad-dependent transcription or cooperate with TGF-β to potentiate its oncogenic activity, while TGF-β signaling can in turn control RTK signaling by regulating their activities or expression. This review summarizes current understandings of the interplay between TGF-β signaling and RTKs and its influence on tumor development.

Affinity of antigen encounter and other early B-cell signals determine B-cell fate

PubMed Central

Benson, Micah J; Erickson, Loren D; Gleeson, Michael W; Noelle, Randolph J

2010-01-01

Three possible effector fates await the naïve follicular B cell following antigen stimulation in thymus-dependent reactions. Short-lived plasma cells produce an initial burst of germline-encoded protective antibodies, and long-lived plasma cells and memory B cells arise from the germinal center and function to enhance and sustain the humoral immune response. The inherent B-cell receptor affinity of naïve follicular B cells and the contribution of other early B-cell signals pre-determines the pattern of transcription factor expression and the differentiation path taken by these cells. High initial B-cell receptor affinity shunts naïve follicular B-cell clones towards the short-lived plasma cell fate, whereas modest-affinity clones are skewed towards a plasma cell fate and low-affinity clones are recruited into the germinal center and are selected for both long-lived plasma cells and memory B cell pathways. In the germinal center reaction, increased levels of the transcription factor interferon regulatory factor-4 drive the molecular program that dictates differentiation into the long-lived plasma cell phenotype but has no impact on the memory B cell compartment. We hypothesize that graded interferon regulatory factor-4 levels driven by signals to B cells, including B-cell receptor signal strength, are responsible for this branch point in the B-cell terminal differentiation pathway. PMID:17433651

Epidermal Growth Factor Receptor Transactivation by the Cannabinoid Receptor (CB1) and Transient Receptor Potential Vanilloid 1 (TRPV1) Induces Differential Responses in Corneal Epithelial Cells

DTIC Science & Technology

2010-01-01

induced Ca2þ signaling as well as phospholipase D (PLD)-mediated phosphatidic acid formation (Islam and Akhtar, 2000; Kang et al., 2000, 2001; Mazie et...Epithelial cell motility is triggered by activation of the EGF receptor through phosphatidic acid signaling. J. Cell Sci. 119, 1645e1654. McIntosh, B.T...buffer. Cell lysates were centrifuged and supernatants were collected for measuring proteins with a bichinchoninic acid assay (BCA) protein assay kit

IRS-1: essential for insulin- and IL-4-stimulated mitogenesis in hematopoietic cells.

PubMed

Wang, L M; Myers, M G; Sun, X J; Aaronson, S A; White, M; Pierce, J H

1993-09-17

Although several interleukin-3 (IL-3)-dependent cell lines proliferate in response to IL-4 or insulin, the 32D line does not. Insulin and IL-4 sensitivity was restored to 32D cells by expression of IRS-1, the principal substrate of the insulin receptor. Although 32D cells possessed receptors for both factors, they lacked the IRS-1--related protein, 4PS, which becomes phosphorylated by tyrosine in insulin- or IL-4--responsive lines after stimulation. These results indicate that factors that bind unrelated receptors can use similar mitogenic signaling pathways in hematopoietic cells and that 4PS and IRS-1 are functionally similar proteins that are essential for insulin- and IL-4--induced proliferation.

Inhibition of insulin-like growth factor receptor-1 reduces necroptosis-related markers and attenuates LPS-induced lung injury in mice.

PubMed

Lee, Su Hwan; Shin, Ju Hye; Song, Joo Han; Leem, Ah Young; Park, Moo Suk; Kim, Young Sam; Chang, Joon; Chung, Kyung Soo

2018-04-15

Insulin-like growth factor-1 (IGF-1) levels are known to increase in the bronchoalveolar lavage fluid (BALF) of patients with acute respiratory distress syndrome. Herein, we investigated the role of IGF-1 in lipopolysaccharide (LPS)-induced lung injury. In LPS-treated cells, expressions of receptor-interacting protein 3 (RIP3) and phosphorylated mixed lineage kinase domain-like protein (MLKL) were decreased in IGF-1 receptor small interfering RNA (siRNA)-treated cells compared to control cells. The levels of pro-inflammatory cytokines including interleukin (IL)-1β, IL-6, IL-10, tumour necrosis factor-α, and macrophage inflammatory protein 2/C-X-C motif chemokine ligand 2 in the supernatant were significantly reduced in IGF-1 receptor siRNA-treated cells compared to control cells. In LPS-induced murine lung injury model, total cell counts, polymorphonuclear leukocytes counts, and pro-inflammatory cytokine levels in the BALF were significantly lower and histologically detected lung injury was less common in the group treated with IGF-1 receptor monoclonal antibody compared to the non-treated group. On western blotting, RIP3 and phosphorylated MLKL expressions were relatively decreased in the IGF-1 receptor monoclonal antibody group compared to the non-treated group. IGF-1 may be associated with RIP3-mediated necroptosis in vitro, while blocking of the IGF-1 pathway may reduce LPS-induced lung injuries in vivo. Copyright © 2018 Elsevier Inc. All rights reserved.

MATRIX METALLOPROTEINS (MMP)-MEDIATED PHOSPHORYLATION OF THE EPIDERMAL GROWTH FACTOR RECEPTOR (EGFR) IN HUMAN AIRWAY EPITHELIAL CELLS (HAEC) EXPOSED TO ZINC (ZN)

EPA Science Inventory

Matrix Metalloproteinase (MMP)-Mediated Phosphorylation of The Epidermal Growth Factor Receptor (EGFR) in Human Airway Epithelial Cells (HAEC) Exposed to Zinc (Zn)
Weidong Wu, James M. Samet, Robert Silbajoris, Lisa A. Dailey, Lee M. Graves, and Philip A. Bromberg
Center fo...

An essential role for IL-2 receptor in regulatory T cell function

PubMed Central

Levine, Andrew G; Fan, Xiying; Klein, Ulf; Zheng, Ye; Gasteiger, Georg; Feng, Yongqiang; Fontenot, Jason D.; Rudensky, Alexander Y.

2016-01-01

Regulatory T (Treg) cells, expressing abundant amounts of the IL-2 receptor (IL-2R), are reliant on IL-2 produced by activated T cells. This feature implied a key role for a simple network based on IL-2 consumption by Treg cells in their suppressor function. However, congenital deficiency in IL-2R results in reduced expression of the Treg cell lineage specification factor Foxp3, confounding experimental efforts to understand the role of IL-2R expression and signaling in Treg suppressor function. Using genetic gain and loss of function approaches, we demonstrate that IL-2 capture is dispensable for control of CD4+ T cells, but is important for limiting CD8+ T cell activation, and that IL-2R dependent STAT5 transcription factor activation plays an essential role in Treg cell suppressor function separable from T cell receptor signaling. PMID:27595233

Productive interaction between transmembrane mutants of the bovine papillomavirus E5 protein and the platelet-derived growth factor beta receptor.

PubMed

Lai, Char-Chang; Edwards, Anne P B; DiMaio, Daniel

2005-02-01

The bovine papillomavirus E5 protein is a 44-amino-acid transmembrane protein that transforms cells by binding to the transmembrane region of the cellular platelet-derived growth factor (PDGF) beta receptor, resulting in sustained receptor signaling. However, there are published reports that certain mutants with amino acid substitutions in the membrane-spanning segment of the E5 protein transform cells without activating the PDGF beta receptor. We re-examined several of these transmembrane mutants, and here we present five lines of evidence that these mutants do in fact activate the PDGF beta receptor, resulting in cellular signaling and transformation.

Regulation of fibroblast growth factor receptor signalling and trafficking by Src and Eps8.

PubMed

Auciello, Giulio; Cunningham, Debbie L; Tatar, Tulin; Heath, John K; Rappoport, Joshua Z

2013-01-15

Fibroblast growth factor receptors (FGFRs) mediate a wide spectrum of cellular responses that are crucial for development and wound healing. However, aberrant FGFR activity leads to cancer. Activated growth factor receptors undergo stimulated endocytosis, but can continue to signal along the endocytic pathway. Endocytic trafficking controls the duration and intensity of signalling, and growth factor receptor signalling can lead to modifications of trafficking pathways. We have developed live-cell imaging methods for studying FGFR dynamics to investigate mechanisms that coordinate the interplay between receptor trafficking and signal transduction. Activated FGFR enters the cell following recruitment to pre-formed clathrin-coated pits (CCPs). However, FGFR activation stimulates clathrin-mediated endocytosis; FGF treatment increases the number of CCPs, including those undergoing endocytosis, and this effect is mediated by Src and its phosphorylation target Eps8. Eps8 interacts with the clathrin-mediated endocytosis machinery and depletion of Eps8 inhibits FGFR trafficking and immediate Erk signalling. Once internalized, FGFR passes through peripheral early endosomes en route to recycling and degredative compartments, through an Src- and Eps8-dependent mechanism. Thus Eps8 functions as a key coordinator in the interplay between FGFR signalling and trafficking. This work provides the first detailed mechanistic analysis of growth factor receptor clustering at the cell surface through signal transduction and endocytic trafficking. As we have characterised the Src target Eps8 as a key regulator of FGFR signalling and trafficking, and identified the early endocytic system as the site of Eps8-mediated effects, this work provides novel mechanistic insight into the reciprocal regulation of growth factor receptor signalling and trafficking.

GRB2 Interaction with the Ecotropic Murine Leukemia Virus Receptor, mCAT-1, Controls Virus Entry and Is Stimulated by Virus Binding

PubMed Central

Chen, Zeming; Kolokoltsov, Andrey A.; Wang, Jia; Adhikary, Shramika; Lorinczi, Marta; Elferink, Lisa A.

2012-01-01

For retroviruses such as HIV-1 and murine leukemia virus (MLV), active receptor recruitment and trafficking occur during viral entry. However, the underlying mechanisms and cellular factors involved in the process are largely uncharacterized. The viral receptor for ecotropic MLV (eMLV), a classical model for retrovirus infection mechanisms and pathogenesis, is mouse cationic amino acid transporter 1 (mCAT-1). Growth factor receptor-bound protein 2 (GRB2) is an adaptor protein that has been shown to couple cell surface receptors, such as epidermal growth factor receptor (EGFR) and hepatocyte growth factor receptor, to intracellular signaling events. Here we examined if GRB2 could also play a role in controlling infection by retroviruses by affecting receptor function. The GRB2 RNA interference (RNAi)-mediated suppression of endogenous GRB2 resulted in a consistent and significant reduction of virus binding and membrane fusion. The binding between eMLV and cells promoted increased GRB2–mCAT-1 interactions, as detected by immunoprecipitation. Consistently, the increased colocalization of GRB2 and mCAT-1 signals was detected by confocal microscopy. This association was time dependent and paralleled the kinetics of cell-virus membrane fusion. Interestingly, unlike the canonical binding pattern seen for GRB2 and growth factor receptors, GRB2–mCAT-1 binding does not depend on the GRB2-SH2 domain-mediated recognition of tyrosine phosphorylation on the receptor. The inhibition of endogenous GRB2 led to a reduction in surface levels of mCAT-1, which was detected by immunoprecipitation and by a direct binding assay using a recombinant MLV envelope protein receptor binding domain (RBD). Consistent with this observation, the expression of a dominant negative GRB2 mutant (R86K) resulted in the sequestration of mCAT-1 from the cell surface into intracellular vesicles. Taken together, these findings suggest a novel role for GRB2 in ecotropic MLV entry and infection by facilitating mCAT-1 trafficking. PMID:22090132

GRB2 interaction with the ecotropic murine leukemia virus receptor, mCAT-1, controls virus entry and is stimulated by virus binding.

PubMed

Chen, Zeming; Kolokoltsov, Andrey A; Wang, Jia; Adhikary, Shramika; Lorinczi, Marta; Elferink, Lisa A; Davey, Robert A

2012-02-01

For retroviruses such as HIV-1 and murine leukemia virus (MLV), active receptor recruitment and trafficking occur during viral entry. However, the underlying mechanisms and cellular factors involved in the process are largely uncharacterized. The viral receptor for ecotropic MLV (eMLV), a classical model for retrovirus infection mechanisms and pathogenesis, is mouse cationic amino acid transporter 1 (mCAT-1). Growth factor receptor-bound protein 2 (GRB2) is an adaptor protein that has been shown to couple cell surface receptors, such as epidermal growth factor receptor (EGFR) and hepatocyte growth factor receptor, to intracellular signaling events. Here we examined if GRB2 could also play a role in controlling infection by retroviruses by affecting receptor function. The GRB2 RNA interference (RNAi)-mediated suppression of endogenous GRB2 resulted in a consistent and significant reduction of virus binding and membrane fusion. The binding between eMLV and cells promoted increased GRB2-mCAT-1 interactions, as detected by immunoprecipitation. Consistently, the increased colocalization of GRB2 and mCAT-1 signals was detected by confocal microscopy. This association was time dependent and paralleled the kinetics of cell-virus membrane fusion. Interestingly, unlike the canonical binding pattern seen for GRB2 and growth factor receptors, GRB2-mCAT-1 binding does not depend on the GRB2-SH2 domain-mediated recognition of tyrosine phosphorylation on the receptor. The inhibition of endogenous GRB2 led to a reduction in surface levels of mCAT-1, which was detected by immunoprecipitation and by a direct binding assay using a recombinant MLV envelope protein receptor binding domain (RBD). Consistent with this observation, the expression of a dominant negative GRB2 mutant (R86K) resulted in the sequestration of mCAT-1 from the cell surface into intracellular vesicles. Taken together, these findings suggest a novel role for GRB2 in ecotropic MLV entry and infection by facilitating mCAT-1 trafficking.

Effects of icotinib, a novel epidermal growth factor receptor tyrosine kinase inhibitor, in EGFR-mutated non-small cell lung cancer.

PubMed

Yang, Guangdie; Yao, Yinan; Zhou, Jianya; Zhao, Qiong

2012-06-01

Epidermal growth factor receptor (EGFR) is one of the most promising targets for non-small cell lung cancer (NSCLC). Our study demonstrated the antitumor effects of icotinib hydrochloride, a highly selective epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI), in two EGFR-mutated lung cancer cell lines compared to A549, a cell line without EGFR mutations. We incubated PC-9 and HCC827 human lung cancer cell lines both with (E746-A750) mutations with various concentrations of icotinib and gefitinib for 48 h. Cell proliferation and migration were determined using a real-time cell invasion and migration assay and cytotoxicity assay. Apoptosis was assessed by measuring Annexin V staining using flow cytometry. The antitumor effects of icotinib compared to gefitinib were similar and were most effective in reducing the proliferation of EGFR-mutated cells compared to non-mutated controls. Our results suggest the possibility of icotinib as a new therapeutic agent of EGFR-mutated cancer cells, which has the potential to be used in the first-line treatment of EGFR-mutated NSCLC.

Efficacy of chemotherapy after first-line gefitinib therapy in EGFR mutation-positive advanced non-small cell lung cancer-data from a randomized Phase III study comparing gefitinib with carboplatin plus paclitaxel (NEJ002).

PubMed

Miyauchi, Eisaku; Inoue, Akira; Kobayashi, Kunihiko; Maemondo, Makoto; Sugawara, Shunichi; Oizumi, Satoshi; Isobe, Hiroshi; Gemma, Akihiko; Saijo, Yasuo; Yoshizawa, Hirohisa; Hagiwara, Koichi; Nukiwa, Toshihiro

2015-07-01

Epidermal growth factor receptor tyrosine kinase inhibitors are effective as first-line therapy for advanced non-small cell lung cancer patients harboring epidermal growth factor receptor mutations. However, it is unknown whether second-line platinum-based chemotherapy after epidermal growth factor receptor tyrosine kinase inhibitor therapy could lead to better outcomes. We evaluated the efficacy of second-line platinum-based chemotherapy after gefitinib for advanced non-small cell lung cancers harboring epidermal growth factor receptor mutations (the NEJ002 study). Seventy-one non-small cell lung cancers, treated with gefitinib as first-line therapy and then receiving platinum-based chemotherapy as second-line therapy were evaluated in NEJ002. Patients were evaluated for antitumor response to second-line chemotherapy by computed tomography according to the criteria of the Response Evaluation Criteria in Solid Tumors group (version 1.0). Of the 71 patients receiving platinum-based chemotherapy after first-line gefitinib, a partial response was documented in 25.4% (18/71), stable disease in 43.7% (31/71) and progression of disease in 21.1% (15/71). The objective response and disease control rates were 25.4% (18/71) and 69% (49/71), respectively. There was no significant difference between first- and second-line chemotherapy in objective response and disease control rates for advanced non-small cell lung cancer harboring activating epidermal growth factor receptor mutations. In the analysis of epidermal growth factor receptor mutation types, the objective responses of deletions in exon 19 and a point mutation in exon 21 (L858R) were 27.3% (9/33) and 28.1% (9/32), respectively, but these differences between objective response rates were not significant. The efficacy of second-line platinum-based chemotherapy followed at progression by gefitinib was similar to first-line platinum-based chemotherapy, and epidermal growth factor receptor mutation types did not influence the efficacy of second-line platinum-based chemotherapy. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Hepatitis C virus utilizes VLDLR as a novel entry pathway.

PubMed

Ujino, Saneyuki; Nishitsuji, Hironori; Hishiki, Takayuki; Sugiyama, Kazuo; Takaku, Hiroshi; Shimotohno, Kunitada

2016-01-05

Various host factors are involved in the cellular entry of hepatitis C virus (HCV). In addition to the factors previously reported, we discovered that the very-low-density lipoprotein receptor (VLDLR) mediates HCV entry independent of CD81. Culturing Huh7.5 cells under hypoxic conditions significantly increased HCV entry as a result of the expression of VLDLR, which was not expressed under normoxic conditions in this cell line. Ectopic VLDLR expression conferred susceptibility to HCV entry of CD81-deficient Huh7.5 cells. Additionally, VLDLR-mediated HCV entry was not affected by the knockdown of cellular factors known to act as HCV receptors or HCV entry factors. Because VLDLR is expressed in primary human hepatocytes, our results suggest that VLDLR functions in vivo as an HCV receptor independent of canonical CD81-mediated HCV entry.

Receptor-mediated cytotoxicity of alpha-MSH fragments containing melphalan in a human melanoma cell line.

PubMed

Morandini, R; Süli-Vargha, H; Libert, A; Loir, B; Botyánszki, J; Medzihradszky, K; Ghanem, G

1994-01-02

Four alpha-MSH drug conjugates have been synthesized, 2 C-terminal (Pep 3 and 4) and 2 central fragments (Pep 1 and 2), the latter being the 4-10 sequence known to be the main alpha-MSH-receptor-recognition site. Melphalan was introduced into each sequence at different locations. Their ability to recognize alpha-MSH receptors as well as their cytotoxic effects were compared in 3 cell lines: melanoma, carcinoma and fibroblast cells. Pep 1 and 2 were able to specifically bind to MSH receptors on melanoma cells by displacing labelled alpha-MSH from its binding sites at concentrations similar to the 4-10 heptapeptide sequence known to contain the main receptor-recognition site. They subsequently penetrate the cell, most probably by a receptor internalization mechanism, since about half of their effect could be inhibited by competition at the receptor level. Significant and selective cytotoxic effects to melanoma cells could be observed after only 2 hr exposure to the drug conjugates. Interestingly, these 2 conjugates, differing only in melphalan position, showed completely different cytotoxicity in terms of IC50 values, Pep 1 being 24 times more toxic to all cells; but the 2 were equally specific to melanoma cells. However, they both were less toxic to all cells than melphalan itself. Furthermore, Pep 1 and 2 were able to block the receptor and, unlike Pep 3 and 4, their cytotoxic effect could be significantly inhibited by an alpha-MSH agonist. Pep 3 and 4 were 5 to 10 times less toxic than melphalan to melanoma and carcinoma cells and 50 times less to fibroblast cells, and did not show any cell-type selectivity. They were less toxic than Pep 1 to melanoma and carcinoma cells by a factor of 2, but equally toxic to fibroblasts. In contrast, they were more toxic than Pep 2 to fibroblasts, melanoma and carcinoma by a factor of 3, 10 and 24 respectively. Our data strongly suggest a receptor-mediated cytotoxicity mechanism occurring with alpha-MSH central fragments in human melanoma cells due to the presence of alpha-MSH-specific receptors. This mechanism appeared to be both peptide- and cell-type-specific.

Regulation of steroid hormone receptors and coregulators during the cell cycle highlights potential novel function in addition to roles as transcription factors

PubMed Central

Zheng, Yingfeng; Murphy, Leigh C.

2016-01-01

Cell cycle progression is tightly controlled by several kinase families including Cyclin-Dependent Kinases, Polo-Like Kinases, and Aurora Kinases. A large amount of data show that steroid hormone receptors and various components of the cell cycle, including cell cycle regulated kinases, interact, and this often results in altered transcriptional activity of the receptor. Furthermore, steroid hormones, through their receptors, can also regulate the transcriptional expression of genes that are required for cell cycle regulation. However, emerging data suggest that steroid hormone receptors may have roles in cell cycle progression independent of their transcriptional activity. The following is a review of how steroid receptors and their coregulators can regulate or be regulated by the cell cycle machinery, with a particular focus on roles independent of transcription in G2/M. PMID:26778927

Dual agonist Surrobody™ simultaneously activates death receptors DR4 and DR5 to induce cancer cell death

PubMed Central

Milutinovic, Snezana; Kashyap, Arun K.; Yanagi, Teruki; Wimer, Carina; Zhou, Sihong; O' Neil, Ryann; Kurtzman, Aaron L.; Faynboym, Alexsandr; Xu, Li; Hannum, Charles H.; Diaz, Paul W.; Matsuzawa, Shu-ichi; Horowitz, Michael; Horowitz, Lawrence; Bhatt, Ramesh R.; Reed, John C.

2015-01-01

Death receptors of the Tumor Necrosis Factor (TNF) family are found on surface of most cancer cells and their activation typically kills cancer cells through the stimulation of the extrinsic apoptotic pathway. The endogenous ligand for death receptors-4 and -5 (DR4 and DR5) is Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand, TRAIL (Apo2L). Since most untransformed cells are not susceptible to TRAIL-induced apoptosis, death receptor activators have emerged as promising cancer therapeutic agents. One strategy to stimulate death receptors in cancer patients is to use soluble human recombinant TRAIL protein, but this agent has limitations of a short half-life and decoy receptor sequestration. Another strategy that attempted to evade decoy receptor sequestration and to provide improved pharmacokinetic properties was to generate DR4 or DR5 agonist antibodies. The resulting monoclonal agonist antibodies overcame the limitations of short half-life and avoided decoy receptor sequestration, but are limited by activating only one of the two death receptors. Here, we describe a DR4 and DR5 dual agonist produced using Surrobody™ technology that activates both DR4 and DR5 to induce apoptotic death of cancer cells in vitro and in vivo and also avoids decoy receptor sequestration. This fully human anti-DR4/DR5 Surrobody displays superior potency to DR4- and DR5-specific antibodies, even when combined with TRAIL-sensitizing pro-apoptotic agents. Moreover, cancer cells were less likely to acquire resistance to Surrobody than either anti-DR4 or anti-DR5 mono-specific antibodies. Taken together, Surrobody shows promising preclinical pro-apoptotic activity against cancer cells, meriting further exploration of its potential as a novel cancer therapeutic agent. PMID:26516157

A Nasal Epithelial Receptor for Staphylococcus aureus WTA Governs Adhesion to Epithelial Cells and Modulates Nasal Colonization

PubMed Central

Faulstich, Manuela; Grau, Timo; Severin, Yannik; Unger, Clemens; Hoffmann, Wolfgang H.; Rudel, Thomas; Autenrieth, Ingo B.; Weidenmaier, Christopher

2014-01-01

Nasal colonization is a major risk factor for S. aureus infections. The mechanisms responsible for colonization are still not well understood and involve several factors on the host and the bacterial side. One key factor is the cell wall teichoic acid (WTA) of S. aureus, which governs direct interactions with nasal epithelial surfaces. We report here the first receptor for the cell wall glycopolymer WTA on nasal epithelial cells. In several assay systems this type F-scavenger receptor, termed SREC-I, bound WTA in a charge dependent manner and mediated adhesion to nasal epithelial cells in vitro. The impact of WTA and SREC-I interaction on epithelial adhesion was especially pronounced under shear stress, which resembles the conditions found in the nasal cavity. Most importantly, we demonstrate here a key role of the WTA-receptor interaction in a cotton rat model of nasal colonization. When we inhibited WTA mediated adhesion with a SREC-I antibody, nasal colonization in the animal model was strongly reduced at the early onset of colonization. More importantly, colonization stayed low over an extended period of 6 days. Therefore we propose targeting of this glycopolymer-receptor interaction as a novel strategy to prevent or control S. aureus nasal colonization. PMID:24788600

Blockade of vascular endothelial growth factor receptor and epidermal growth factor receptor signaling for therapy of metastatic human pancreatic cancer.

PubMed

Baker, Cheryl H; Solorzano, Carmen C; Fidler, Isaiah J

2002-04-01

We determined whether concurrent blockage of vascular endothelial growth factor (VEGF) receptor and epidermal growth factor (EGF) receptor signaling by two novel tyrosine kinase inhibitors, PTK 787 and PKI 166, respectively, can inhibit angiogenesis and, hence, the growth and metastasis of human pancreatic carcinoma in nude mice. Highly metastatic human pancreatic carcinoma L3.6pl cells were injected into the pancreas of nude mice. Seven days later, groups of mice began receiving oral doses of PTK 787 and PKI 166 three times weekly. Some groups of mice also received i.p. injections of gemcitabine twice a week. The mice were necropsied when the control mice became moribund. Treatment with PTK 787 and PKI 166, with gemcitabine alone, or with the combination of PTK 787, PKI 166, and gemcitabine produced 69, 50, and 97% reduction in the volume of pancreatic tumors, respectively. Administration of protein tyrosine kinase inhibitors and gemcitabine also significantly decreased the incidence of lymph node and liver metastasis. The therapeutic efficacy directly correlated with a decrease in circulating proangiogenic molecules (VEGF, interleukin-8), a decrease in microvessel density, a decrease in proliferating cell nuclear antigen staining, and an increase in apoptosis of tumor cells and endothelial cells. Therapies produced by combining gemcitabine with either PKI 166 or PTK 787 were similar to those produced by combining gemcitabine with both PKI 166 and PTK 787. These results suggest that blockade of either epidermal growth factor receptor or VEGF receptor signaling combined with chemotherapy provides an effective approach to the therapy of pancreatic cancer.

Nuclear receptor co-regulator Kruppel-like factor 9 and prohibitin 2 expression in estrogen-induced epithelial cell proliferation in the mouse uterus

USDA-ARS?s Scientific Manuscript database

Estrogen, acting through its cognate receptor estrogen receptor-' (ESR1), is a critical regulator of uterine endometrial epithelial proliferation. Although the dynamic communication between endometrial stromal (ST) and epithelial cells is considered to be an important component in this process, key ...

Novel synergistic mechanism for sst2 somatostatin and TNFalpha receptors to induce apoptosis: crosstalk between NF-kappaB and JNK pathways.

PubMed

Guillermet-Guibert, J; Saint-Laurent, N; Davenne, L; Rochaix, P; Cuvillier, O; Culler, M D; Pradayrol, L; Buscail, L; Susini, C; Bousquet, C

2007-02-01

Somatostatin is a multifunctional hormone that modulates cell proliferation, differentiation and apoptosis. Mechanisms for somatostatin-induced apoptosis are at present mostly unsolved. Therefore, we investigated whether somatostatin receptor subtype 2 (sst2) induces apoptosis in the nontransformed murine fibroblastic NIH3T3 cells. Somatostatin receptor subtype 2 expression induced an executioner caspase-mediated apoptosis through a tyrosine phosphatase SHP-1 (Src homology domain phosphatase-1)-dependent stimulation of nuclear factor kappa B (NF-kappaB) activity and subsequent inhibition of the mitogen-activated protein kinase JNK. Tumor necrosis factor alpha (TNFalpha) stimulated both NF-kappaB and c-Jun NH2-terminal kinase (JNK) activities, which had opposite action on cell survival. Importantly, sst2 sensitized NIH3T3 cells to TNFalpha-induced apoptosis by (1) upregulating TNFalpha receptor protein expression, and sensitizing to TNFalpha-induced caspase-8 activation; (2) enhancing TNFalpha-mediated activation of NF-kappaB, resulting in JNK inhibition and subsequent executioner caspase activation and cell death. We have here unraveled a novel signaling mechanism for a G protein-coupled receptor, which directly triggers apoptosis and crosstalks with a death receptor to enhance death ligand-induced apoptosis.

Low-dose naltrexone targets the opioid growth factor-opioid growth factor receptor pathway to inhibit cell proliferation: mechanistic evidence from a tissue culture model.

PubMed

Donahue, Renee N; McLaughlin, Patricia J; Zagon, Ian S

2011-09-01

Naltrexone (NTX) is an opioid antagonist that inhibits or accelerates cell proliferation in vivo when utilized in a low (LDN) or high (HDN) dose, respectively. The mechanism of opioid antagonist action on growth is not well understood. We established a tissue culture model of LDN and HDN using short-term and continuous opioid receptor blockade, respectively, in human ovarian cancer cells, and found that the duration of opioid receptor blockade determines cell proliferative response. The alteration of growth by NTX also was detected in cells representative of pancreatic, colorectal and squamous cell carcinomas. The opioid growth factor (OGF; [Met(5)]-enkephalin) and its receptor (OGFr) were responsible for mediating the action of NTX on cell proliferation. NTX upregulated OGF and OGFr at the translational but not at the transcriptional level. The mechanism of inhibition by short-term NTX required p16 and/or p21 cyclin-dependent inhibitory kinases, but was not dependent on cell survival (necrosis, apoptosis). Sequential administration of short-term NTX and OGF had a greater inhibitory effect on cell proliferation than either agent alone. Given the parallels between short-term NTX in vitro and LDN in vivo, we now demonstrate at the molecular level that the OGF-OGFr axis is a common pathway that is essential for the regulation of cell proliferation by NTX.

Recent insights into the implications of metabolism in plasmacytoid dendritic cell innate functions: Potential ways to control these functions.

PubMed

Saas, Philippe; Varin, Alexis; Perruche, Sylvain; Ceroi, Adam

2017-01-01

There are more and more data concerning the role of cellular metabolism in innate immune cells, such as macrophages or conventional dendritic cells. However, few data are available currently concerning plasmacytoid dendritic cells (PDC), another type of innate immune cells. These cells are the main type I interferon (IFN) producing cells, but they also secrete other pro-inflammatory cytokines (e.g., tumor necrosis factor or interleukin [IL]-6) or immunomodulatory factors (e.g., IL-10 or transforming growth factor-β). Through these functions, PDC participate in antimicrobial responses or maintenance of immune tolerance, and have been implicated in the pathophysiology of several autoimmune diseases, as well as in tumor immune escape mechanisms. Recent data support the idea that the glycolytic pathway (or glycolysis), as well as lipid metabolism (including both cholesterol and fatty acid metabolism) may impact some innate immune functions of PDC or may be involved in these functions after Toll-like receptor (TLR) 7/9 triggering. The kinetics of glycolysis after TLR7/9 triggering may differ between human and murine PDC. In mouse PDC, metabolism changes promoted by TLR7/9 activation may depend on an autocrine/paracrine loop, implicating type I IFN and its receptor IFNAR. This could explain a delayed glycolysis in mouse PDC. Moreover, PDC functions can be modulated by the metabolism of cholesterol and fatty acids. This may occur via the production of lipid ligands that activate nuclear receptors (e.g., liver X receptor [LXR]) in PDC or through limiting intracellular cholesterol pool size (by statin or LXR agonist treatment) in these cells. Finally, lipid-activated nuclear receptors (i.e., LXR or peroxisome proliferator activated receptor) may also directly interact with pro-inflammatory transcription factors, such as NF-κB. Here, we discuss how glycolysis and lipid metabolism may modulate PDC functions and how this may be harnessed in pathological situations where PDC play a detrimental role.

Recent insights into the implications of metabolism in plasmacytoid dendritic cell innate functions: Potential ways to control these functions

PubMed Central

Saas, Philippe; Varin, Alexis; Perruche, Sylvain; Ceroi, Adam

2017-01-01

There are more and more data concerning the role of cellular metabolism in innate immune cells, such as macrophages or conventional dendritic cells. However, few data are available currently concerning plasmacytoid dendritic cells (PDC), another type of innate immune cells. These cells are the main type I interferon (IFN) producing cells, but they also secrete other pro-inflammatory cytokines (e.g., tumor necrosis factor or interleukin [IL]-6) or immunomodulatory factors (e.g., IL-10 or transforming growth factor-β). Through these functions, PDC participate in antimicrobial responses or maintenance of immune tolerance, and have been implicated in the pathophysiology of several autoimmune diseases, as well as in tumor immune escape mechanisms. Recent data support the idea that the glycolytic pathway (or glycolysis), as well as lipid metabolism (including both cholesterol and fatty acid metabolism) may impact some innate immune functions of PDC or may be involved in these functions after Toll-like receptor (TLR) 7/9 triggering. The kinetics of glycolysis after TLR7/9 triggering may differ between human and murine PDC. In mouse PDC, metabolism changes promoted by TLR7/9 activation may depend on an autocrine/paracrine loop, implicating type I IFN and its receptor IFNAR. This could explain a delayed glycolysis in mouse PDC. Moreover, PDC functions can be modulated by the metabolism of cholesterol and fatty acids. This may occur via the production of lipid ligands that activate nuclear receptors (e.g., liver X receptor [LXR]) in PDC or through limiting intracellular cholesterol pool size (by statin or LXR agonist treatment) in these cells. Finally, lipid-activated nuclear receptors (i.e., LXR or peroxisome proliferator activated receptor) may also directly interact with pro-inflammatory transcription factors, such as NF-κB. Here, we discuss how glycolysis and lipid metabolism may modulate PDC functions and how this may be harnessed in pathological situations where PDC play a detrimental role. PMID:28580131

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.

Glucose Deprivation Induces ATF4-Mediated Apoptosis through TRAIL Death Receptors

PubMed Central

Iurlaro, Raffaella; Püschel, Franziska; León-Annicchiarico, Clara Lucía; O'Connor, Hazel; Martin, Seamus J.; Palou-Gramón, Daniel; Lucendo, Estefanía

2017-01-01

ABSTRACT Metabolic stress occurs frequently in tumors and in normal tissues undergoing transient ischemia. Nutrient deprivation triggers, among many potential cell death-inducing pathways, an endoplasmic reticulum (ER) stress response with the induction of the integrated stress response transcription factor ATF4. However, how this results in cell death remains unknown. Here we show that glucose deprivation triggered ER stress and induced the unfolded protein response transcription factors ATF4 and CHOP. This was associated with the nontranscriptional accumulation of TRAIL receptor 1 (TRAIL-R1) (DR4) and with the ATF4-mediated, CHOP-independent induction of TRAIL-R2 (DR5), suggesting that cell death in this context may involve death receptor signaling. Consistent with this, the ablation of TRAIL-R1, TRAIL-R2, FADD, Bid, and caspase-8 attenuated cell death, although the downregulation of TRAIL did not, suggesting ligand-independent activation of TRAIL receptors. These data indicate that stress triggered by glucose deprivation promotes the ATF4-dependent upregulation of TRAIL-R2/DR5 and TRAIL receptor-mediated cell death. PMID:28242652

Transcription Factor IRF4 Promotes CD8+ T Cell Exhaustion and Limits the Development of Memory-like T Cells during Chronic Infection.

PubMed

Man, Kevin; Gabriel, Sarah S; Liao, Yang; Gloury, Renee; Preston, Simon; Henstridge, Darren C; Pellegrini, Marc; Zehn, Dietmar; Berberich-Siebelt, Friederike; Febbraio, Mark A; Shi, Wei; Kallies, Axel

2017-12-19

During chronic stimulation, CD8 + T cells acquire an exhausted phenotype characterized by expression of inhibitory receptors, down-modulation of effector function, and metabolic impairments. T cell exhaustion protects from excessive immunopathology but limits clearance of virus-infected or tumor cells. We transcriptionally profiled antigen-specific T cells from mice infected with lymphocytic choriomeningitis virus strains that cause acute or chronic disease. T cell exhaustion during chronic infection was driven by high amounts of T cell receptor (TCR)-induced transcription factors IRF4, BATF, and NFATc1. These regulators promoted expression of inhibitory receptors, including PD-1, and mediated impaired cellular metabolism. Furthermore, they repressed the expression of TCF1, a transcription factor required for memory T cell differentiation. Reducing IRF4 expression restored the functional and metabolic properties of antigen-specific T cells and promoted memory-like T cell development. These findings indicate that IRF4 functions as a central node in a TCR-responsive transcriptional circuit that establishes and sustains T cell exhaustion during chronic infection. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Cellular localization of the activated EGFR determines its effect on cell growth in MDA-MB-468 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hyatt, Dustin C.; Ceresa, Brian P.

2008-11-01

The epidermal growth factor (EGF) receptor (EGFR) is a ubiquitously expressed receptor tyrosine kinase that regulates diverse cell functions that are dependent upon cell type, the presence of downstream effectors, and receptor density. In addition to activating biochemical pathways, ligand stimulation causes the EGFR to enter the cell via clathrin-coated pits. Endocytic trafficking influences receptor signaling by controlling the duration of EGFR phosphorylation and coordinating the receptor's association with downstream effectors. To better understand the individual contributions of cell surface and cytosolic EGFRs on cell physiology, we used EGF that was conjugated to 900 nm polystyrene beads (EGF-beads). EGF-beads canmore » stimulate the EGFR and retain the activated receptor at the plasma membrane. In MDA-MB-468 cells, a breast cancer cell line that over-expresses the EGFR, only internalized, activated EGFRs stimulate caspase-3 and induce cell death. Conversely, signaling cascades triggered from activated EGFR retained at the cell surface inhibit caspase-3 and promote cell proliferation. Thus, through endocytosis, the activated EGFR can differentially regulate cell growth in MDA-MB-468 cells.« less

Allelic exchange of pheromones and their receptors reprograms sexual identity in Cryptococcus neoformans.

PubMed

Stanton, Brynne C; Giles, Steven S; Staudt, Mark W; Kruzel, Emilia K; Hull, Christina M

2010-02-26

Cell type specification is a fundamental process that all cells must carry out to ensure appropriate behaviors in response to environmental stimuli. In fungi, cell identity is critical for defining "sexes" known as mating types and is controlled by components of mating type (MAT) loci. MAT-encoded genes function to define sexes via two distinct paradigms: 1) by controlling transcription of components common to both sexes, or 2) by expressing specially encoded factors (pheromones and their receptors) that differ between mating types. The human fungal pathogen Cryptococcus neoformans has two mating types (a and alpha) that are specified by an extremely unusual MAT locus. The complex architecture of this locus makes it impossible to predict which paradigm governs mating type. To identify the mechanism by which the C. neoformans sexes are determined, we created strains in which the pheromone and pheromone receptor from one mating type (a) replaced the pheromone and pheromone receptor of the other (alpha). We discovered that these "alpha(a)" cells effectively adopt a new mating type (that of a cells); they sense and respond to alpha factor, they elicit a mating response from alpha cells, and they fuse with alpha cells. In addition, alpha(a) cells lose the alpha cell type-specific response to pheromone and do not form germ tubes, instead remaining spherical like a cells. Finally, we discovered that exogenous expression of the diploid/dikaryon-specific transcription factor Sxi2a could then promote complete sexual development in crosses between alpha and alpha(a) strains. These data reveal that cell identity in C. neoformans is controlled fully by three kinds of MAT-encoded proteins: pheromones, pheromone receptors, and homeodomain proteins. Our findings establish the mechanisms for maintenance of distinct cell types and subsequent developmental behaviors in this unusual human fungal pathogen.

Effects of Secreted Mast Cell Mediators on Retinal Pigment Epithelial Cells: Focus on Mast Cell Tryptase.

PubMed

Arai, Rei; Usui-Ouchi, Ayumi; Ito, Yosuke; Mashimo, Keitaro; Murakami, Akira; Ebihara, Nobuyuki

2017-01-01

Numerous mast cells are present in the choroid, but the effects of mast cell mediators on retinal pigment epithelial (RPE) cells are not well understood. We investigated the influence of mast cell mediators on RPE cells in vitro, focusing on tryptase. Expression of receptors was examined by the reverse transcription polymerase chain reaction. We also assessed production of interleukin 8 and vascular endothelial growth factor (VEGF) after RPE cells were stimulated with mast cell mediators by using an antibody array and enzyme-linked immunosorbent assay. Furthermore, we investigated the influence of tryptase on RPE cell migration and integrity by the scratch assay and the transepithelial resistance. RPE cells expressed protease-activated receptor 2 (PAR2), histamine receptor 1, tumor necrosis factor- α (TNF- α ) receptor 1, and CCR 1, 3, 4, 8, and 11. Tryptase, PAR2 agonists, histamine, and TNF- α all enhanced interleukin 8 production by RPE cells, while only tryptase enhanced VEGF production. Tryptase also enhanced expression of phosphorylated extracellular signal-regulated kinases 1/2, resulting in increased migration of RPE cells. However, tryptase did not alter epithelial integrity or the expression of zonula occludens-1 and junctional adhesion molecule-A by RPE cells. Mast cell mediators, especially tryptase, may influence RPE cell inflammation.

New targeted therapies in pancreatic cancer.

PubMed

Seicean, Andrada; Petrusel, Livia; Seicean, Radu

2015-05-28

Patients with pancreatic cancer have a poor prognosis with a median survival of 4-6 mo and a 5-year survival of less than 5%. Despite therapy with gemcitabine, patient survival does not exceed 6 mo, likely due to natural resistance to gemcitabine. Therefore, it is hoped that more favorable results can be obtained by using guided immunotherapy against molecular targets. This review summarizes the new leading targeted therapies in pancreatic cancers, focusing on passive and specific immunotherapies. Passive immunotherapy may have a role for treatment in combination with radiochemotherapy, which otherwise destroys the immune system along with tumor cells. It includes mainly therapies targeting against kinases, including epidermal growth factor receptor, Ras/Raf/mitogen-activated protein kinase cascade, human epidermal growth factor receptor 2, insulin growth factor-1 receptor, phosphoinositide 3-kinase/Akt/mTOR and hepatocyte growth factor receptor. Therapies against DNA repair genes, histone deacetylases, microRNA, and pancreatic tumor tissue stromal elements (stromal extracellular matric and stromal pathways) are also discussed. Specific immunotherapies, such as vaccines (whole cell recombinant, peptide, and dendritic cell vaccines), adoptive cell therapy and immunotherapy targeting tumor stem cells, have the role of activating antitumor immune responses. In the future, treatments will likely include personalized medicine, tailored for numerous molecular therapeutic targets of multiple pathogenetic pathways.

Localization of brain-derived neurotrophic factor, neurotrophin-4, tropomyosin-related kinase b receptor, and p75 NTR receptor by high-resolution immunohistochemistry on the adult mouse neuromuscular junction.

PubMed

Garcia, Neus; Tomàs, Marta; Santafe, Manel M; Lanuza, M Angel; Besalduch, Nuria; Tomàs, Josep

2010-03-01

Neurotrophins and their receptors, the trk receptor tyrosine kinases (trks) and p75(NTR), are differentially expressed among the cell types that make up synapses. It is important to determine the precise location of these molecules involved in neurotransmission. Here we use immunostaining and Western blotting to study the localization and expression of neurotrophin brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT-4) and the receptors tropomyosin-related kinase b (trkB) and p75(NTR) at the adult neuromuscular junction. Our confocal immunofluorescence results on the whole mounts of the mouse Levator auris longus muscle and on semithin cross-sections showed that BDNF, NT-4, trkB, and p75(NTR) were localized on the three cells in the neuromuscular synapse (motor axons, post-synaptic muscle and Schwann cells).

Altered receptor trafficking in Huntingtin Interacting Protein 1-transformed cells.

PubMed

Rao, Dinesh S; Bradley, Sarah V; Kumar, Priti D; Hyun, Teresa S; Saint-Dic, Djenann; Oravecz-Wilson, Katherine; Kleer, Celina G; Ross, Theodora S

2003-05-01

The clathrin-associated protein, Huntingtin Interacting Protein 1 (HIP1), is overexpressed in multiple human epithelial tumors. Here, we report that HIP1 is a novel oncoprotein that transforms cells. HIP1-transformed cells, in contrast to RasV12-transformed cells, have dysregulation of multiple receptors involved in clathrin trafficking. Examples include upregulation of the epidermal growth factor receptor (EGFR) and the transferrin receptor. Furthermore, accumulation of transferrin and EGF in the HIP1-transformed cells was increased, and breast tumors that had EGFR expressed also had HIP1 upregulated. Thus, HIP1 overexpression promotes tumor formation and is associated with a general alteration in receptor trafficking. HIP1 is the first endocytic protein to be directly implicated in tumor formation.

Age-related changes in expression of transforming growth factor-beta and receptors in cells of intervertebral discs.

PubMed

Matsunaga, Shunji; Nagano, Satoshi; Onishi, Toshiyuki; Morimoto, Norio; Suzuki, Shusaku; Komiya, Setsuro

2003-01-01

The authors conducted a study to determine age-related changes in expression of transforming growth factor (TGF)-beta1, -beta2, -beta3, and Type I and Type II receptors in various cells in the nucleus pulposus and anulus fibrosus. Immunolocalization of TGFbetas and Type I and II receptors was examined during the aging process of cervical intervertebral discs in senescence-accelerated mice (SAM). The TGFbeta family has important roles for cellular function of various tissues. Its role in disc aging, however, is unknown. Detailed information on the temporal and spatial localization of TGFbetas and their receptors in discs is required before discussing introduction of them clinically into the intervertebral disc. Three groups of five SAM each were used. The groups of SAM were age 8, 24, and 50 weeks, respectively. Hematoxylin and eosin staining and immunohistochemical study involving specific antibodies for TGFbeta1, -beta2, -beta3, and Types I and II TGF receptors were performed. Intervertebral discs exhibited degenerative change with advancing age. The TGFbetas and their receptors were present in the fibrocartilaginous cells within the anulus fibrosus and notochord-like cells within the nucleus pulposus of young mice. Expression of TGFbetas and Type I and Type II receptors changed markedly in the cells within the anulus fibrosus during the aging process. The TGFbetas and their receptors were present in cells within the nucleus pulposus and the anulus fibrosus of young mice, and their expression decreased with age.

Nuclear Receptor Co-Regulator Krüppel-like Factor 9 in Human Endometrial Stromal Cell Differentiation

USDA-ARS?s Scientific Manuscript database

The biological actions of ligand-bound estrogen (E) and progesterone (P) receptors are dependent on coregulator partner proteins. We have identified Krüppel-like Factor 9 (KLF9) as important for E and P actions in endometrial cells. Ablation of KLF9 in mice resulted in subfertility due partly to alt...

Integrated Experimental and Model-based Analysis Reveals the Spatial Aspects of EGFR Activation Dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shankaran, Harish; Zhang, Yi; Chrisler, William B.

2012-10-02

The epidermal growth factor receptor (EGFR) belongs to the ErbB family of receptor tyrosine kinases, and controls a diverse set of cellular responses relevant to development and tumorigenesis. ErbB activation is a complex process involving receptor-ligand binding, receptor dimerization, phosphorylation, and trafficking (internalization, recycling and degradation), which together dictate the spatio-temporal distribution of active receptors within the cell. The ability to predict this distribution, and elucidation of the factors regulating it, would help to establish a mechanistic link between ErbB expression levels and the cellular response. Towards this end, we constructed mathematical models for deconvolving the contributions of receptor dimerizationmore » and phosphorylation to EGFR activation, and to examine the dependence of these processes on sub-cellular location. We collected experimental datasets for EGFR activation dynamics in human mammary epithelial cells, with the specific goal of model parameterization, and used the data to estimate parameters for several alternate models. Model-based analysis indicated that: 1) signal termination via receptor dephosphorylation in late endosomes, prior to degradation, is an important component of the response, 2) less than 40% of the receptors in the cell are phosphorylated at any given time, even at saturating ligand doses, and 3) receptor dephosphorylation rates at the cell surface and early endosomes are comparable. We validated the last finding by measuring EGFR dephosphorylation rates at various times following ligand addition both in whole cells, and in endosomes using ELISAs and fluorescent imaging. Overall, our results provide important information on how EGFR phosphorylation levels are regulated within cells. Further, the mathematical model described here can be extended to determine receptor dimer abundances in cells co-expressing various levels of ErbB receptors. This study demonstrates that an iterative cycle of experiments and modeling can be used to gain mechanistic insight regarding complex cell signaling networks.« less

Antimuscle atrophy effect of nicotine targets muscle satellite cells partly through an α7 nicotinic receptor in a murine hindlimb ischemia model.

PubMed

Kakinuma, Yoshihiko; Noguchi, Tatsuya; Okazaki, Kayo; Oikawa, Shino; Iketani, Mitsue; Kurabayashi, Atsushi; Kurabayashi, Mutsumi; Furihata, Mutsuo; Sato, Takayuki

2014-07-01

We have recently identified that donepezil, an anti-Alzheimer drug, accelerates angiogenesis in a murine hindlimb ischemia (HLI) model. However, the precise mechanisms are yet to be fully elucidated, particularly whether the effects are derived from endothelial cells alone or from other nonvascular cells. Further investigation of the HLI model revealed that nicotine accelerated angiogenesis by activation of vascular endothelial cell growth factor (VEGF) synthesis through nicotinic receptors in myogenic cells, that is, satellite cells, in vivo and upregulated the expression of angiogenic factors, for example, VEGF and fibroblast growth factor 2, in vitro. As a result, nicotine prevented skeletal muscle from ischemia-induced muscle atrophy and upregulated myosin heavy chain expression in vitro. The in vivo anti-atrophy effect of nicotine on muscle was also observed in galantamine, another anti-Alzheimer drug, playing as an allosteric potentiating ligand. Such effects of nicotine were attenuated in α7 nicotinic receptor knockout mice. In contrast, PNU282987, an α7 nicotinic receptor agonist, comparably salvaged skeletal muscle, which was affected by HLI. These results suggest that cholinergic signals also target myogenic cells and have inhibiting roles in muscle loss by ischemia-induced muscle atrophy. Copyright © 2014 Mosby, Inc. All rights reserved.

Retinal vasculopathy is reduced by dietary salt restriction: involvement of Glia, ENaCα, and the renin-angiotensin-aldosterone system.

PubMed

Deliyanti, Devy; Armani, Roksana; Casely, David; Figgett, William A; Agrotis, Alex; Wilkinson-Berka, Jennifer L

2014-09-01

Neovascularization and vaso-obliteration are vision-threatening events that develop by interactions between retinal vascular and glial cells. A high-salt diet is causal in cardiovascular and renal disease, which is linked to modulation of the renin-angiotensin-aldosterone system. However, it is not known whether dietary salt influences retinal vasculopathy and if the renin-angiotensin-aldosterone system is involved. We examined whether a low-salt (LS) diet influenced vascular and glial cell injury and the renin-angiotensin-aldosterone system in ischemic retinopathy. Pregnant Sprague Dawley rats were fed LS (0.03% NaCl) or normal salt (0.3% NaCl) diets, and ischemic retinopathy was induced in the offspring. An LS diet reduced retinal neovascularization and vaso-obliteration, the mRNA and protein levels of the angiogenic factors, vascular endothelial growth factor, and erythropoietin. Microglia, which influence vascular remodeling in ischemic retinopathy, were reduced by LS as was tumor necrosis factor-α. Macroglial Müller cells maintain the integrity of the blood-retinal barrier, and in ischemic retinopathy, LS reduced their gliosis and also vascular leakage. In retina, LS reduced mineralocorticoid receptor, angiotensin type 1 receptor, and renin mRNA levels, whereas, as expected, plasma levels of aldosterone and renin were increased. The aldosterone/mineralocorticoid receptor-sensitive epithelial sodium channel alpha (ENaCα), which is expressed in Müller cells, was increased in ischemic retinopathy and reduced by LS. In cultured Müller cells, high salt increased ENaCα, which was prevented by mineralocorticoid receptor and angiotensin type 1 receptor blockade. Conversely, LS reduced ENaCα, angiotensin type 1 receptor, and mineralocorticoid receptor expression. An LS diet reduced retinal vasculopathy, by modulating glial cell function and the retinal renin-angiotensin-aldosterone system. © 2014 American Heart Association, Inc.

Changes in expression and secretion patterns of fibroblast growth factor 8 and Sonic Hedgehog signaling pathway molecules during murine neural stem/progenitor cell differentiation in vitro☆

PubMed Central

Lu, Jiang; Lu, Kehuan; Li, Dongsheng

2012-01-01

In the present study, we investigated the dynamic expression of fibroblast growth factor 8 and Sonic Hedgehog signaling pathway related factors in the process of in vitro hippocampal neural stem/progenitor cell differentiation from embryonic Sprague-Dawley rats or embryonic Kunming species mice, using fluorescent quantitative reverse transcription-PCR and western blot analyses. Results demonstrated that the dynamic expression of fibroblast growth factor 8 was similar to fibroblast growth factor receptor 1 expression but not to other fibroblast growth factor receptors. Enzyme-linked immunosorbent assay demonstrated that fibroblast growth factor 8 and Sonic Hedgehog signaling pathway protein factors were secreted by neural cells into the intercellular niche. Our experimental findings indicate that fibroblast growth factor 8 and Sonic Hedgehog expression may be related to the differentiation of neural stem/progenitor cells. PMID:25624789

The DNA replication licensing factor miniature chromosome maintenance 7 is essential for RNA splicing of epidermal growth factor receptor, c-Met, and platelet-derived growth factor receptor.

PubMed

Chen, Zhang-Hui; Yu, Yan P; Michalopoulos, George; Nelson, Joel; Luo, Jian-Hua

2015-01-16

Miniature chromosome maintenance 7 (MCM7) is an essential component of DNA replication licensing complex. Recent studies indicate that MCM7 is amplified and overexpressed in a variety of human malignancies. In this report, we show that MCM7 binds SF3B3. The binding motif is located in the N terminus (amino acids 221-248) of MCM7. Knockdown of MCM7 or SF3B3 significantly increased unspliced RNA of epidermal growth factor receptor, platelet-derived growth factor receptor, and c-Met. A dramatic drop of reporter gene expression of the oxytocin exon 1-intron-exon 2-EGFP construct was also identified in SF3B3 and MCM7 knockdown PC3 and DU145 cells. The MCM7 or SF3B3 depleted cell extract failed to splice reporter RNA in in vitro RNA splicing analyses. Knockdown of SF3B3 and MCM7 leads to an increase of cell death of both PC3 and DU145 cells. Such cell death induction is partially rescued by expressing spliced c-Met. To our knowledge, this is the first report suggesting that MCM7 is a critical RNA splicing factor, thus giving significant new insight into the oncogenic activity of this protein. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Inhibiting the Epidermal Growth Factor Receptor | Center for Cancer Research

Cancer.gov

The Epidermal Growth Factor Receptor (EGFR) is a widely distributed cell surface receptor that responds to several extracellular signaling molecules through an intracellular tyrosine kinase, which phosphorylates target enzymes to trigger a downstream molecular cascade. Since the discovery that EGFR mutations and amplifications are critical in a number of cancers, efforts have

The epidermal growth factor receptor (EGFR) promotes uptake of influenza A viruses (IAV) into host cells.

PubMed

Eierhoff, Thorsten; Hrincius, Eike R; Rescher, Ursula; Ludwig, Stephan; Ehrhardt, Christina

2010-09-09

Influenza A viruses (IAV) bind to sialic-acids at cellular surfaces and enter cells by using endocytotic routes. There is evidence that this process does not occur constitutively but requires induction of specific cellular signals, including activation of PI3K that promotes virus internalization. This implies engagement of cellular signaling receptors during viral entry. Here, we present first indications for an interplay of IAV with receptor tyrosine kinases (RTKs). As representative RTK family-members the epidermal growth factor receptor (EGFR) and the c-Met receptor were studied. Modulation of expression or activity of both RTKs resulted in altered uptake of IAV, showing that these receptors transmit entry relevant signals upon virus binding. More detailed studies on EGFR function revealed that virus binding lead to clustering of lipid-rafts, suggesting that multivalent binding of IAV to cells induces a signaling platform leading to activation of EGFR and other RTKs that in turn facilitates IAV uptake.

The Epidermal Growth Factor Receptor (EGFR) Promotes Uptake of Influenza A Viruses (IAV) into Host Cells

PubMed Central

Eierhoff, Thorsten; Hrincius, Eike R.; Rescher, Ursula; Ludwig, Stephan; Ehrhardt, Christina

2010-01-01

Influenza A viruses (IAV) bind to sialic-acids at cellular surfaces and enter cells by using endocytotic routes. There is evidence that this process does not occur constitutively but requires induction of specific cellular signals, including activation of PI3K that promotes virus internalization. This implies engagement of cellular signaling receptors during viral entry. Here, we present first indications for an interplay of IAV with receptor tyrosine kinases (RTKs). As representative RTK family-members the epidermal growth factor receptor (EGFR) and the c-Met receptor were studied. Modulation of expression or activity of both RTKs resulted in altered uptake of IAV, showing that these receptors transmit entry relevant signals upon virus binding. More detailed studies on EGFR function revealed that virus binding lead to clustering of lipid-rafts, suggesting that multivalent binding of IAV to cells induces a signaling platform leading to activation of EGFR and other RTKs that in turn facilitates IAV uptake. PMID:20844577

Hepatocyte growth factor induces proliferation and differentiation of multipotent and erythroid hemopoietic progenitors.

PubMed

Galimi, F; Bagnara, G P; Bonsi, L; Cottone, E; Follenzi, A; Simeone, A; Comoglio, P M

1994-12-01

Hepatocyte growth factor (HGF) is a mesenchymal derived growth factor known to induce proliferation and "scattering" of epithelial and endothelial cells. Its receptor is the tyrosine kinase encoded by the c-MET protooncogene. Here we show that highly purified recombinant HGF stimulates hemopoietic progenitors to form colonies in vitro. In the presence of erythropoietin, picomolar concentrations of HGF induced the formation of erythroid burst-forming unit colonies from CD34-positive cells purified from human bone marrow, peripheral blood, or umbilical cord blood. The growth stimulatory activity was restricted to the erythroid lineage. HGF also stimulated the formation of multipotent CFU-GEMM colonies. This effect is synergized by stem cell factor, the ligand of the tyrosine kinase receptor encoded by the c-KIT protooncogene, which is active on early hemopoietic progenitors. By flow cytometry analysis, the receptor for HGF was found to be expressed on the cell surface in a fraction of CD34+ progenitors. Moreover, in situ hybridization experiments showed that HGF receptor mRNA is highly expressed in embryonic erythroid cells (megaloblasts). HGF mRNA was also found to be produced in the embryonal liver. These data show that HGF plays a direct role in the control of proliferation and differentiation of erythroid progenitors, and they suggest that it may be one of the long-sought mediators of paracrine interactions between stromal and hemopoietic cells within the hemopoietic microenvironment.

Signaling by Kit protein-tyrosine kinase--the stem cell factor receptor.

PubMed

Roskoski, Robert

2005-11-11

Signaling by stem cell factor and Kit, its receptor, plays important roles in gametogenesis, hematopoiesis, mast cell development and function, and melanogenesis. Moreover, human and mouse embryonic stem cells express Kit transcripts. Stem cell factor exists as both a soluble and a membrane-bound glycoprotein while Kit is a receptor protein-tyrosine kinase. The complete absence of stem cell factor or Kit is lethal. Deficiencies of either produce defects in red and white blood cell production, hypopigmentation, and sterility. Gain-of-function mutations of Kit are associated with several human neoplasms including acute myelogenous leukemia, gastrointestinal stromal tumors, and mastocytomas. Kit consists of an extracellular domain, a transmembrane segment, a juxtamembrane segment, and a protein kinase domain that contains an insert of about 80 amino acid residues. Binding of stem cell factor to Kit results in receptor dimerization and activation of protein kinase activity. The activated receptor becomes autophosphorylated at tyrosine residues that serve as docking sites for signal transduction molecules containing SH2 domains. The adaptor protein APS, Src family kinases, and Shp2 tyrosyl phosphatase bind to phosphotyrosine 568. Shp1 tyrosyl phosphatase and the adaptor protein Shc bind to phosphotyrosine 570. C-terminal Src kinase homologous kinase and the adaptor Shc bind to both phosphotyrosines 568 and 570. These residues occur in the juxtamembrane segment of Kit. Three residues in the kinase insert domain are phosphorylated and attract the adaptor protein Grb2 (Tyr703), phosphatidylinositol 3-kinase (Tyr721), and phospholipase Cgamma (Tyr730). Phosphotyrosine 900 in the distal kinase domain binds phosphatidylinositol 3-kinase which in turn binds the adaptor protein Crk. Phosphotyrosine 936, also in the distal kinase domain, binds the adaptor proteins APS, Grb2, and Grb7. Kit has the potential to participate in multiple signal transduction pathways as a result of interaction with several enzymes and adaptor proteins.

The biologic role of ganglioside in neuronal differentiation--effects of GM1 ganglioside on human neuroblastoma SH-SY5Y cells.

PubMed Central

Lee, M. C.; Lee, W. S.; Park, C. S.; Juhng, S. W.

1994-01-01

Human neuroblastoma SH-SY5Y cell is a cloned cell line which has many attractive features for the study of neuronal proliferation and neurite outgrowth, because it has receptors for insulin, IGF-I and PDGF. Gangliosides are sialic acid containing glycosphingolipids which form an integral part of the plasma membrane of many mammalian cells. They inhibit cell growth mediated by tyrosine kinase receptors and ligand-stimulated tyrosine kinase activity, and autophosphorylation of EGF(epidermal growth factor) and PDGF receptors. The experiment was designed to study the effects of GM1 ganglioside on growth of human neuroblastoma SH-SY5Y cells stimulated with trophic factor in vitro. The cells were plated in Eagle's minimum essential medium without serum. The number and morphologic change of SH-SY5Y cells were evaluated in the serum free medium added GM1 ganglioside with insulin or PDGF. SH-SY5Y cells were maintained for six days in serum-free medium, and then cultured for over two weeks in serum-free medium containing either insulin or PDGF. The effect of insulin on cell proliferation developed earlier and was more potent than that of PDGF. These proliferative effects were inhibited by GM1 ganglioside, and the cells showed prominent neurites outgrowth. These findings suggest that GM1 ganglioside inhibits the cell proliferation mediated by tyrosine kinase receptors and directly induces neuritogenesis as one of the neurotrophic factors. PMID:7986393

Environmental sensing by mature B cells is controlled by the transcription factors PU.1 and SpiB.

PubMed

Willis, Simon N; Tellier, Julie; Liao, Yang; Trezise, Stephanie; Light, Amanda; O'Donnell, Kristy; Garrett-Sinha, Lee Ann; Shi, Wei; Tarlinton, David M; Nutt, Stephen L

2017-11-10

Humoral immunity requires B cells to respond to multiple stimuli, including antigen, membrane and soluble ligands, and microbial products. Ets family transcription factors regulate many aspects of haematopoiesis, although their functions in humoral immunity are difficult to decipher as a result of redundancy between the family members. Here we show that mice lacking both PU.1 and SpiB in mature B cells do not generate germinal centers and high-affinity antibody after protein immunization. PU.1 and SpiB double-deficient B cells have a survival defect after engagement of CD40 or Toll-like receptors (TLR), despite paradoxically enhanced plasma cell differentiation. PU.1 and SpiB regulate the expression of many components of the B cell receptor signaling pathway and the receptors for CD40L, BAFF and TLR ligands. Thus, PU.1 and SpiB enable B cells to appropriately respond to environmental cues.

Transcriptional activation of human mu-opioid receptor gene by insulin-like growth factor-I in neuronal cells is modulated by the transcription factor REST.

PubMed

Bedini, Andrea; Baiula, Monica; Spampinato, Santi

2008-06-01

The human mu-opioid receptor gene (OPRM1) promoter contains a DNA sequence binding the repressor element 1 silencing transcription factor (REST) that is implicated in transcriptional repression. We investigated whether insulin-like growth factor I (IGF-I), which affects various aspects of neuronal induction and maturation, regulates OPRM1 transcription in neuronal cells in the context of the potential influence of REST. A series of OPRM1-luciferase promoter/reporter constructs were transfected into two neuronal cell models, neuroblastoma-derived SH-SY5Y cells and PC12 cells. In the former, endogenous levels of human mu-opioid receptor (hMOPr) mRNA were evaluated by real-time PCR. IGF-I up-regulated OPRM1 transcription in: PC12 cells lacking REST, in SH-SY5Y cells transfected with constructs deficient in the REST DNA binding element, or when REST was down-regulated in retinoic acid-differentiated cells. IGF-I activates the signal transducer and activator of transcription-3 signaling pathway and this transcription factor, binding to the signal transducer and activator of transcription-1/3 DNA element located in the promoter, increases OPRM1 transcription. We propose that a reduction in REST is a critical switch enabling IGF-I to up-regulate hMOPr. These findings help clarify how hMOPr expression is regulated in neuronal cells.

Intermittent hypoxia induces the proliferation of rat vascular smooth muscle cell with the increases in epidermal growth factor family and erbB2 receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kyotani, Yoji, E-mail: cd147@naramed-u.ac.jp; Department of Pharmacy, Nara Medical University Hospital, Kashihara 634-8522; Ota, Hiroyo

Obstructive sleep apnea is characterized by intermittent hypoxia (IH), and associated with cardiovascular diseases, such as stroke and heart failure. These cardiovascular diseases have a relation to atherosclerosis marked by the proliferation of vascular smooth muscle cells (VSMCs). In this study, we investigated the influence of IH on cultured rat aortic smooth muscle cell (RASMC). The proliferation of RASMC was significantly increased by IH without changing the level of apoptosis. In order to see what induces RASMC proliferation, we investigated the influence of normoxia (N)-, IH- and sustained hypoxia (SH)-treated cell conditioned media on RASMC proliferation. IH-treated cell conditioned mediummore » significantly increased RASMC proliferation compared with N-treated cell conditioned medium, but SH-treated cell conditioned medium did not. We next investigated the epidermal growth factor (EGF) family as autocrine growth factors. Among the EGF family, we found significant increases in mRNAs for epiregulin (ER), amphiregulin (AR) and neuregulin-1 (NRG1) in IH-treated cells and mature ER in IH-treated cell conditioned medium. We next investigated the changes in erbB family receptors that are receptors for ER, AR and NRG1, and found that erbB2 receptor mRNA and protein expressions were increased by IH, but not by SH. Phosphorylation of erbB2 receptor at Tyr-1248 that mediates intracellular signaling for several physiological effects including cell proliferation was increased by IH, but not by SH. In addition, inhibitor for erbB2 receptor suppressed IH-induced cell proliferation. These results provide the first demonstration that IH induces VSMC proliferation, and suggest that EGF family, such as ER, AR and NRG1, and erbB2 receptor could be involved in the IH-induced VSMC proliferation. - Highlights: ●In vitro system for intermittent hypoxia (IH) and sustained hypoxia (SH). ●IH, but not SH, induces the proliferation of rat vascular smooth muscle cell. ●Epiregulin mRNA and protein are up-regulated in IH, but not in SH. ●IH-induced erbB2 phosphorylation is attenuated by erbB2 inhibitor. ●EGF family and erbB2 receptor may be involved in IH-induced cell proliferation.« less

Blockage of angiotensin II type I receptor decreases the synthesis of growth factors and induces apoptosis in C6 cultured cells and C6 rat glioma

PubMed Central

Arrieta, O; Guevara, P; Escobar, E; García-Navarrete, R; Pineda, B; Sotelo, J

2005-01-01

Angiotensin II (Ang II) is a main effector peptide in the renin–angiotensin system and participates in the regulation of vascular tone. It also has a role in the expression of growth factors that induce neovascularisation which is closely associated to the growth of malignant gliomas. We have shown that the selective blockage of the AT1 receptor of angiotensin inhibites tumour growth, cell proliferation and angiogenesis of C6 rat glioma. The aim of this study was to study the effects of the blockage of AT1 receptor on the synthesis of growth factors, and in the genesis of apoptosis in cultured C6 glioma cells and in rats with C6 glioma. Administration of losartan at doses of 40 or 80 mg kg−1 to rats with C6 glioma significantly decreased tumoral volume and production of platelet-derived growth factor, vascular endothelial growth factor and basic fibroblast growth factor. It also induced apoptosis in a dose-dependent manner. Administration of Ang II increased cell proliferation of cultured C6 cells which decreased by the administration of losartan. Our results suggest that the selective blockage of AT1 diminishes tumoral growth through inhibition of growth factors and promotion of apoptosis. PMID:15785746

Integrated experimental and model-based analysis reveals the spatial aspects of EGFR activation dynamics

PubMed Central

Shankaran, Harish; Zhang, Yi; Chrisler, William B.; Ewald, Jonathan A.; Wiley, H. Steven; Resat, Haluk

2012-01-01

The epidermal growth factor receptor (EGFR) belongs to the ErbB family of receptor tyrosine kinases, and controls a diverse set of cellular responses relevant to development and tumorigenesis. ErbB activation is a complex process involving receptor-ligand binding, receptor dimerization, phosphorylation, and trafficking (internalization, recycling and degradation), which together dictate the spatio-temporal distribution of active receptors within the cell. The ability to predict this distribution, and elucidation of the factors regulating it, would help to establish a mechanistic link between ErbB expression levels and the cellular response. Towards this end, we constructed mathematical models to determine the contributions of receptor dimerization and phosphorylation to EGFR activation, and to examine the dependence of these processes on sub-cellular location. We collected experimental datasets for EGFR activation dynamics in human mammary epithelial cells, with the specific goal of model parameterization, and used the data to estimate parameters for several alternate models. Model-based analysis indicated that: 1) signal termination via receptor dephosphorylation in late endosomes, prior to degradation, is an important component of the response, 2) less than 40% of the receptors in the cell are phosphorylated at any given time, even at saturating ligand doses, and 3) receptor phosphorylation kinetics at the cell surface and early endosomes are comparable. We validated the last finding by measuring the EGFR dephosphorylation rates at various times following ligand addition both in whole cells and in endosomes using ELISAs and fluorescent imaging. Overall, our results provide important information on how EGFR phosphorylation levels are regulated within cells. This study demonstrates that an iterative cycle of experiments and modeling can be used to gain mechanistic insight regarding complex cell signaling networks. PMID:22952062

A critical role for transcription factor Smad4 in T cell function independent of transforming growth factor beta receptor signaling

PubMed Central

Gu, Ai-Di; Zhang, Song; Wang, Yunqi; Xiong, Hui; Curtis, Thomas A.; Wan, Yisong Y.

2014-01-01

Summary Transforming growth factor-beta (TGF-β) suppresses T cell function to maintain self-tolerance and to promote tumor immune evasion. Yet how Smad4, a transcription factor component of TGF-β signaling, regulates T cell function remains unclear. Here we have demonstrated an essential role for Smad4 in promoting T cell function during autoimmunity and anti-tumor immunity. Smad4 deletion rescued the lethal autoimmunity resulting from transforming growth factor-beta receptor (TGF-βR) deletion and compromised T-cell-mediated tumor rejection. While Smad4 was dispensable for T cell generation, homeostasis and effector function, it was essential for T cell proliferation following activation in vitro and in vivo. The transcription factor Myc was identified to mediate Smad4-controlled T cell proliferation. This study thus reveals a requirement of Smad4 for T-cell-mediated autoimmunity and tumor rejection, which is beyond the current paradigm. It highlights a TGF-βR-independent role for Smad4 in promoting T cell function, autoimmunity and anti-tumor immunity. PMID:25577439

A critical role for transcription factor Smad4 in T cell function that is independent of transforming growth factor β receptor signaling.

PubMed

Gu, Ai-Di; Zhang, Song; Wang, Yunqi; Xiong, Hui; Curtis, Thomas A; Wan, Yisong Y

2015-01-20

Transforming growth factor-beta (TGF-β) suppresses T cell function to maintain self-tolerance and to promote tumor immune evasion. Yet how Smad4, a transcription factor component of TGF-β signaling, regulates T cell function remains unclear. Here we have demonstrated an essential role for Smad4 in promoting T cell function during autoimmunity and anti-tumor immunity. Smad4 deletion rescued the lethal autoimmunity resulting from transforming growth factor-beta receptor (TGF-βR) deletion and compromised T-cell-mediated tumor rejection. Although Smad4 was dispensable for T cell generation, homeostasis, and effector function, it was essential for T cell proliferation after activation in vitro and in vivo. The transcription factor Myc was identified to mediate Smad4-controlled T cell proliferation. This study thus reveals a requirement of Smad4 for T-cell-mediated autoimmunity and tumor rejection, which is beyond the current paradigm. It highlights a TGF-βR-independent role for Smad4 in promoting T cell function, autoimmunity, and anti-tumor immunity. Copyright © 2015 Elsevier Inc. All rights reserved.

Insulin-Like Growth Factor Receptor Signaling is Necessary for Epidermal Growth Factor Mediated Proliferation of SVZ Neural Precursors in vitro Following Neonatal Hypoxia–Ischemia

PubMed Central

Alagappan, Dhivyaa; Ziegler, Amber N.; Chidambaram, Shravanthi; Min, Jungsoo; Wood, Teresa L.; Levison, Steven W.

2014-01-01

In this study, we assessed the importance of insulin-like growth factor (IGF) and epidermal growth factor (EGF) receptor co-signaling for rat neural precursor (NP) cell proliferation and self-renewal in the context of a developmental brain injury that is associated with cerebral palsy. Consistent with previous studies, we found that there is an increase in the in vitro growth of subventricular zone NPs isolated acutely after cerebral hypoxia–ischemia; however, when cultured in medium that is insufficient to stimulate the IGF type 1 receptor, neurosphere formation and the proliferative capacity of those NPs was severely curtailed. This reduced growth capacity could not be attributed simply to failure to survive. The growth and self-renewal of the NPs could be restored by addition of both IGF-I and IGF-II. Since the size of the neurosphere is predominantly due to cell proliferation we hypothesized that the IGFs were regulating progression through the cell cycle. Analyses of cell cycle progression revealed that IGF-1R activation together with EGFR co-signaling decreased the percentage of cells in G1 and enhanced cell progression into S and G2. This was accompanied by increases in expression of cyclin D1, phosphorylated histone 3, and phosphorylated Rb. Based on these data, we conclude that coordinate signaling between the EGF receptor and the IGF type 1 receptor is necessary for the normal proliferation of NPs as well as for their reactive expansion after injury. These data indicate that manipulations that maintain or amplify IGF signaling in the brain during recovery from developmental brain injuries will enhance the production of new brain cells to improve neurological function in children who are at risk for developing cerebral palsy. PMID:24904523

Poly(ADP-ribose) polymerase inhibitors sensitize cancer cells to death receptor-mediated apoptosis by enhancing death receptor expression.

PubMed

Meng, X Wei; Koh, Brian D; Zhang, Jin-San; Flatten, Karen S; Schneider, Paula A; Billadeau, Daniel D; Hess, Allan D; Smith, B Douglas; Karp, Judith E; Kaufmann, Scott H

2014-07-25

Recombinant human tumor necrosis factor-α-related apoptosis inducing ligand (TRAIL), agonistic monoclonal antibodies to TRAIL receptors, and small molecule TRAIL receptor agonists are in various stages of preclinical and early phase clinical testing as potential anticancer drugs. Accordingly, there is substantial interest in understanding factors that affect sensitivity to these agents. In the present study we observed that the poly(ADP-ribose) polymerase (PARP) inhibitors olaparib and veliparib sensitize the myeloid leukemia cell lines ML-1 and K562, the ovarian cancer line PEO1, non-small cell lung cancer line A549, and a majority of clinical AML isolates, but not normal marrow, to TRAIL. Further analysis demonstrated that PARP inhibitor treatment results in activation of the FAS and TNFRSF10B (death receptor 5 (DR5)) promoters, increased Fas and DR5 mRNA, and elevated cell surface expression of these receptors in sensitized cells. Chromatin immunoprecipitation demonstrated enhanced binding of the transcription factor Sp1 to the TNFRSF10B promoter in the presence of PARP inhibitor. Knockdown of PARP1 or PARP2 (but not PARP3 and PARP4) not only increased expression of Fas and DR5 at the mRNA and protein level, but also recapitulated the sensitizing effects of the PARP inhibition. Conversely, Sp1 knockdown diminished the PARP inhibitor effects. In view of the fact that TRAIL is part of the armamentarium of natural killer cells, these observations identify a new facet of PARP inhibitor action while simultaneously providing the mechanistic underpinnings of a novel therapeutic combination that warrants further investigation.

Mast cells and mastocytosis

PubMed Central

2008-01-01

Mast cells have been recognized for well over 100 years. With time, human mast cells have been documented to originate from CD34+ cells, and have been implicated in host responses in both innate and acquired immunity. In clinical immunology, they are recognized for their central role in IgE-mediated degranulation and allergic inflammation by virtue of their expression of the high-affinity receptor for IgE and release of potent proinflammatory mediators. In hematology, the clinical disease of mastocytosis is characterized by a pathologic increase of mast cells in tissues, often associated with mutations in KIT, the receptor for stem cell factor. More recently, and with increased understanding of how human mast cells are activated through receptors including the high-affinity receptor for IgE and KIT, specific tyrosine kinase inhibitors have been identified with the potential to interrupt signaling pathways and thus limit the proliferation of mast cells as well as their activation through immunoglobulin receptors. PMID:18684881

Site-Selective Regulation of Platelet-Derived Growth Factor β Receptor Tyrosine Phosphorylation by T-Cell Protein Tyrosine Phosphatase

PubMed Central

Persson, Camilla; Sävenhed, Catrine; Bourdeau, Annie; Tremblay, Michel L.; Markova, Boyka; Böhmer, Frank D.; Haj, Fawaz G.; Neel, Benjamin G.; Elson, Ari; Heldin, Carl-Henrik; Rönnstrand, Lars; Östman, Arne; Hellberg, Carina

2004-01-01

The platelet-derived growth factor (PDGF) β receptor mediates mitogenic and chemotactic signals. Like other tyrosine kinase receptors, the PDGF β receptor is negatively regulated by protein tyrosine phosphatases (PTPs). To explore whether T-cell PTP (TC-PTP) negatively regulates the PDGF β receptor, we compared PDGF β receptor tyrosine phosphorylation in wild-type and TC-PTP knockout (ko) mouse embryos. PDGF β receptors were hyperphosphorylated in TC-PTP ko embryos. Fivefold-higher ligand-induced receptor phosphorylation was observed in TC-PTP ko mouse embryo fibroblasts (MEFs) as well. Reexpression of TC-PTP partly abolished this difference. As determined with site-specific phosphotyrosine antibodies, the extent of hyperphosphorylation varied among different autophosphorylation sites. The phospholipase Cγ1 binding site Y1021, previously implicated in chemotaxis, displayed the largest increase in phosphorylation. The increase in Y1021 phosphorylation was accompanied by increased phospholipase Cγ1 activity and migratory hyperresponsiveness to PDGF. PDGF β receptor tyrosine phosphorylation in PTP-1B ko MEFs but not in PTPɛ ko MEFs was also higher than that in control cells. This increase occurred with a site distribution different from that seen after TC-PTP depletion. PDGF-induced migration was not increased in PTP-1B ko cells. In summary, our findings identify TC-PTP as a previously unrecognized negative regulator of PDGF β receptor signaling and support the general notion that PTPs display site selectivity in their action on tyrosine kinase receptors. PMID:14966296

Role of Glutamine 17 of the Bovine Papillomavirus E5 Protein in Platelet-Derived Growth Factor β Receptor Activation and Cell Transformation

PubMed Central

Klein, Ophir; Polack, Glenda W.; Surti, Toral; Kegler-Ebo, Deena; Smith, Steven O.; DiMaio, Daniel

1998-01-01

The bovine papillomavirus E5 protein is a small, homodimeric transmembrane protein that forms a stable complex with the cellular platelet-derived growth factor (PDGF) β receptor through transmembrane and juxtamembrane interactions, resulting in receptor activation and cell transformation. Glutamine 17 in the transmembrane domain of the 44-amino-acid E5 protein is critical for complex formation and receptor activation, and we previously proposed that glutamine 17 forms a hydrogen bond with threonine 513 of the PDGF β receptor. We have constructed and analyzed mutant E5 proteins containing all possible amino acids at position 17 and examined the ability of these proteins to transform C127 fibroblasts, which express endogenous PDGF β receptor. Although several position 17 mutants were able to transform cells, mutants containing amino acids with side groups that were unable to participate in hydrogen bonding interactions did not form a stable complex with the PDGF β receptor or transform cells, in agreement with the proposed interaction between position 17 of the E5 protein and threonine 513 of the receptor. The nature of the residue at position 17 also affected the ability of the E5 proteins to dimerize. Overall, there was an excellent correlation between the ability of the various E5 mutant proteins to bind the PDGF β receptor, lead to receptor tyrosine phosphorylation, and transform cells. Similar results were obtained in Ba/F3 hematopoietic cells expressing exogenous PDGF β receptor. In addition, treatment of E5-transformed cells with a specific inhibitor of the PDGF receptor tyrosine kinase reversed the transformed phenotype. These results confirm the central importance of the PDGF β receptor in mediating E5 transformation and highlight the critical role of the residue at position 17 of the E5 protein in the productive interaction with the PDGF β receptor. On the basis of molecular modeling analysis and the known chemical properties of the amino acids, we suggest a structural basis for the role of the residue at position 17 in E5 dimerization and in complex formation between the E5 protein and the PDGF β receptor. PMID:9765437

Role of glutamine 17 of the bovine papillomavirus E5 protein in platelet-derived growth factor beta receptor activation and cell transformation.

PubMed

Klein, O; Polack, G W; Surti, T; Kegler-Ebo, D; Smith, S O; DiMaio, D

1998-11-01

The bovine papillomavirus E5 protein is a small, homodimeric transmembrane protein that forms a stable complex with the cellular platelet-derived growth factor (PDGF) beta receptor through transmembrane and juxtamembrane interactions, resulting in receptor activation and cell transformation. Glutamine 17 in the transmembrane domain of the 44-amino-acid E5 protein is critical for complex formation and receptor activation, and we previously proposed that glutamine 17 forms a hydrogen bond with threonine 513 of the PDGF beta receptor. We have constructed and analyzed mutant E5 proteins containing all possible amino acids at position 17 and examined the ability of these proteins to transform C127 fibroblasts, which express endogenous PDGF beta receptor. Although several position 17 mutants were able to transform cells, mutants containing amino acids with side groups that were unable to participate in hydrogen bonding interactions did not form a stable complex with the PDGF beta receptor or transform cells, in agreement with the proposed interaction between position 17 of the E5 protein and threonine 513 of the receptor. The nature of the residue at position 17 also affected the ability of the E5 proteins to dimerize. Overall, there was an excellent correlation between the ability of the various E5 mutant proteins to bind the PDGF beta receptor, lead to receptor tyrosine phosphorylation, and transform cells. Similar results were obtained in Ba/F3 hematopoietic cells expressing exogenous PDGF beta receptor. In addition, treatment of E5-transformed cells with a specific inhibitor of the PDGF receptor tyrosine kinase reversed the transformed phenotype. These results confirm the central importance of the PDGF beta receptor in mediating E5 transformation and highlight the critical role of the residue at position 17 of the E5 protein in the productive interaction with the PDGF beta receptor. On the basis of molecular modeling analysis and the known chemical properties of the amino acids, we suggest a structural basis for the role of the residue at position 17 in E5 dimerization and in complex formation between the E5 protein and the PDGF beta receptor.

Targeting cancer stem cell plasticity through modulation of epidermal growth factor and insulin-like growth factor receptor signaling in head and neck squamous cell cancer.

PubMed

Leong, Hui Sun; Chong, Fui Teen; Sew, Pui Hoon; Lau, Dawn P; Wong, Bernice H; Teh, Bin-Tean; Tan, Daniel S W; Iyer, N Gopalakrishna

2014-09-01

Emerging data suggest that cancer stem cells (CSCs) exist in equilibrium with differentiated cells and that stochastic transitions between these states can account for tumor heterogeneity and drug resistance. The aim of this study was to establish an in vitro system that recapitulates stem cell plasticity in head and neck squamous cell cancers (HNSCCs) and identify the factors that play a role in the maintenance and repopulation of CSCs. Tumor spheres were established using patient-derived cell lines via anchorage-independent cell culture techniques. These tumor spheres were found to have higher aldehyde dehydrogenase (ALD) cell fractions and increased expression of Kruppel-like factor 4, SRY (sex determining region Y)-box 2, and Nanog and were resistant to γ-radiation, 5-fluorouracil, cisplatin, and etoposide treatment compared with monolayer culture cells. Monolayer cultures were subject to single cell cloning to generate clones with high and low ALD fractions. ALDHigh clones showed higher expression of stem cell and epithelial-mesenchymal transition markers compared with ALDLow clones. ALD fractions, representing stem cell fractions, fluctuated with serial passaging, equilibrating at a level specific to each cell line, and could be augmented by the addition of epidermal growth factor (EGF) and/or insulin. ALDHigh clones showed increased EGF receptor (EGFR) and insulin-like growth factor-1 receptor (IGF-1R) phosphorylation, with increased activation of downstream pathways compared with ALDLow clones. Importantly, blocking these pathways using specific inhibitors against EGFR and IGF-1R reduced stem cell fractions drastically. Taken together, these results show that HNSCC CSCs exhibit plasticity, with the maintenance of the stem cell fraction dependent on the EGFR and IGF-1R pathways and potentially amenable to targeted therapeutics. ©AlphaMed Press.

Isotretinoin and FoxO1

PubMed Central

2011-01-01

Oral isotretinoin (13-cis retinoic acid) is the most effective drug in the treatment of acne and restores all major pathogenetic factors of acne vulgaris. isotretinoin is regarded as a prodrug which after isomerizisation to all-trans-retinoic acid (ATRA) induces apoptosis in cells cultured from human sebaceous glands, meibomian glands, neuroblastoma cells, hypothalamic cells, hippocampus cells, Dalton's lymphoma ascites cells, B16F-10 melanoma cells, and neuronal crest cells and others. By means of translational research this paper provides substantial indirect evidence for isotretinoin's mode of action by upregulation of forkhead box class O (FoxO) transcription factors. FoxOs play a pivotal role in the regulation of androgen receptor transactivation, insulin/insulin like growth factor-1 (IGF-1)-signaling, peroxisome proliferator-activated receptor-γ (PPArγ)- and liver X receptor-α (LXrα)-mediated lipogenesis, β-catenin signaling, cell proliferation, apoptosis, reactive oxygene homeostasis, innate and acquired immunity, stem cell homeostasis, as well as anti-cancer effects. An accumulating body of evidence suggests that the therapeutic, adverse, teratogenic and chemopreventive effecs of isotretinoin are all mediated by upregulation of FoxO-mediated gene transcription. These FoxO-driven transcriptional changes of the second response of retinoic acid receptor (RAR)-mediated signaling counterbalance gene expression of acne due to increased growth factor signaling with downregulated nuclear FoxO proteins. The proposed isotretinoin→ATRA→RAR→FoxO interaction offers intriguing new insights into the mode of isotretinoin action and explains most therapeutic, adverse and teratogenic effects of isotretinoin in the treatment of acne by a common mode of FoxO-mediated transcriptional regulation. PMID:22110774

Transcription control and neuronal differentiation by agents that activate the LXR nuclear receptor family.

PubMed

Schmidt, A; Vogel, R; Holloway, M K; Rutledge, S J; Friedman, O; Yang, Z; Rodan, G A; Friedman, E

1999-09-10

LXR and PPAR receptors belong to the nuclear receptor superfamily of transcriptional activating factors. Using ligand-dependent transcription assays, we found that 5-tetradecyloxy-2-furancarboxylic acid (TOFA) transactivates chimeric receptors composed of the glucocorticoid receptor DNA binding domain and the ligand binding regions of PPARalpha, PPARbeta (NUC-1) and LXRbeta (NER) receptors. In the same assays, ligands for PPARs (oleic acid, WY-14643 and L-631,033) and LXRs (hydroxycholesterols) maintain their respective receptor selectivity. TOFA and hydroxycholesterols also stimulate transcription from a minimal fibrinogen promoter that is under the control of AP-1 or NF-kappaB transcription factor binding sites. In addition to their effects on transcription, these LXRbeta activators induce neuronal differentiation in rat pheochromocytoma cells. TOFA and the natural LXR agonist, 22 (R)-hydroxycholesterol, stimulate neurite outgrowth in 55 and 28% of cells, respectively. No neurite outgrowth was induced by the related 22(S)-hydroxycholesterol, which does not activate the LXR family. These results suggest that the hydroxycholesterol signaling pathway has a complex effect on transcription that mediates the activity of TOFA and hydroxycholesterol on neuronal differentiation in pheochromocytoma cells.

Identification of human somatostatin receptor 2 domains involved in internalization and signaling in QGP-1 pancreatic neuroendocrine tumor cell line.

PubMed

Cambiaghi, Valeria; Vitali, Eleonora; Morone, Diego; Peverelli, Erika; Spada, Anna; Mantovani, Giovanna; Lania, Andrea Gerardo

2017-04-01

Somatostatin exerts inhibitory effects on hormone secretion and cell proliferation via five receptor subtypes (SST1-SST5), whose internalization is regulated by β-arrestins. The receptor domains involved in these effects have been only partially elucidated. The aim of the study is to characterize the molecular mechanism and determinants responsible for somatostatin receptor 2 internalization and signaling in pancreatic neuroendocrine QGP-1 cell line, focusing on the third intracellular loop and carboxyl terminal domains. We demonstrated that in cells transfected with somatostatin receptor 2 third intracellular loop mutant, no differences in β-arrestins recruitment and receptor internalization were observed after somatostatin receptor 2 activation in comparison with cells bearing wild-type somatostatin receptor 2. Conversely, the truncated somatostatin receptor 2 failed to recruit β-arrestins and to internalize after somatostatin receptor 2 agonist (BIM23120) incubation. Moreover, the inhibitory effect of BIM23120 on cell proliferation, cyclin D1 expression, P-ERK1/2 levels, apoptosis and vascular endothelial growth factor secretion was completely lost in cells transfected with either third intracellular loop or carboxyl terminal mutants. In conclusion, we demonstrated that somatostatin receptor 2 internalization requires intact carboxyl terminal while the effects of SS on cell proliferation, angiogenesis and apoptosis mediated by somatostatin receptor 2 need the integrity of both third intracellular loop and carboxyl terminal.

Peroxisome Proliferator Activated Receptor-α/Hypoxia Inducible Factor-1α Interplay Sustains Carbonic Anhydrase IX and Apoliprotein E Expression in Breast Cancer Stem Cells

PubMed Central

Papi, Alessio; Storci, Gianluca; Guarnieri, Tiziana; De Carolis, Sabrina; Bertoni, Sara; Avenia, Nicola; Sanguinetti, Alessandro; Sidoni, Angelo; Santini, Donatella; Ceccarelli, Claudio; Taffurelli, Mario; Orlandi, Marina; Bonafé, Massimiliano

2013-01-01

Aims Cancer stem cell biology is tightly connected to the regulation of the pro-inflammatory cytokine network. The concept of cancer stem cells “inflammatory addiction” leads to envisage the potential role of anti-inflammatory molecules as new anti-cancer targets. Here we report on the relationship between nuclear receptors activity and the modulation of the pro-inflammatory phenotype in breast cancer stem cells. Methods Breast cancer stem cells were expanded as mammospheres from normal and tumor human breast tissues and from tumorigenic (MCF7) and non tumorigenic (MCF10) human breast cell lines. Mammospheres were exposed to the supernatant of breast tumor and normal mammary gland tissue fibroblasts. Results In mammospheres exposed to the breast tumor fibroblasts supernatant, autocrine tumor necrosis factor-α signalling engenders the functional interplay between peroxisome proliferator activated receptor-α and hypoxia inducible factor-1α (PPARα/HIF1α). The two proteins promote mammospheres formation and enhance each other expression via miRNA130b/miRNA17-5p-dependent mechanism which is antagonized by PPARγ. Further, the PPARα/HIF1α interplay regulates the expression of the pro-inflammatory cytokine interleukin-6, the hypoxia survival factor carbonic anhydrase IX and the plasma lipid carrier apolipoprotein E. Conclusion Our data demonstrate the importance of exploring the role of nuclear receptors (PPARα/PPARγ) in the regulation of pro-inflammatory pathways, with the aim to thwart breast cancer stem cells functioning. PMID:23372804

Activation of phosphatidylinositol-3-kinase by platelet-derived growth factor and insulin-like growth factor-1 is inhibited by a transmembrane phosphotyrosine phosphatase.

PubMed

Way, B A; Mooney, R A

1993-12-15

Expression of the transmembrane phosphotyrosine phosphatase (PTPase) CD45 has been shown to inhibit hormone-dependent tyrosine phosphorylation and mitogenesis (Mooney, R. A., Freund, G. G., Way, B. A., and Bordwell, K. L. (1992) J. Biol. Chem. 267, 23443-23446). Here the impact of PTPase expression on insulin-like growth factor-1 (IGF-1) and platelet-derived growth factor- (PDGF) dependent activation of PI-3-K was investigated. In PTPase+ cells, IGF-1 and PDGF-dependent PI-3-K activity in antiphosphotyrosine immunoprecipitates was decreased by 62 +/- 13 and 46 +/- 17%, respectively, compared to control cells. Similar decreases in PI-3-K activity associated with anti-PDGF receptor and anti-insulin receptor substrate-1 (IRS-1) immunoprecipitates were also observed. Association of PI-3-K with the hormone-activated PDGF receptor decreased approximately 55%, paralleling its loss of activation in PTPase+ cells. Tyrosine phosphorylation of the 85-kDa subunit of PI-3-K was also inhibited. Similarly, IGF-1 dependent tyrosine phosphorylation of IRS-1 was decreased by 45%, and its association with PI-3-K was decreased by 65% in PTPase+ cells. Finally, PDGF-dependent tyrosine phosphorylation of phospholipase C-gamma 1 and GTPase-activating protein was reduced by 60-70% in the PTPase+ cells as was tyrosine phosphorylation of the PDGF receptor associated with these proteins. In summary, expression of a transmembrane PTPase decreased hormone-dependent PI-3-K activation, tyrosine phosphorylation of receptor substrates, and their association with signaling complexes. These data support a role for transmembrane PTPases in the regulation of receptor signal transduction pathways.

F-spondin inhibits migration and differentiation of osteoclastic precursors.

PubMed

Oka, Hiroko; Mori, Maya; Kihara, Hisae

2011-12-01

Clinically, severe cemental resorption is a rare consequence of periodontitis, although alveolar bone resorption by osteoclasts is one of the main pathologic changes. F-spondin is a secreted neuronal glycoprotein that localizes to the cementum. F-spondin is among the cementum-specific factors in periodontal tissue that have been reported. However, the effects of F-spondin on osteoclastogenesis have not yet been established. We examined the effects of F-spondin on stages of osteoclastogenesis, migration, and differentiation in a mouse osteoclastic precursor model, RAW 264 cells. RAW 264 cells were treated with recombinant F-spondin. Macrophage colony stimulating factor (M-CSF)-induced cell migration was examined by migration assay performed with cell culture inserts. Osteoclastic differentiation was measured by counting tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells. In a transmigration assay, F-spondin significantly downregulated M-CSF-induced cell migration. Further, F-spondin significantly reduced the number of receptor activator of nuclear factor-kappa B ligand-induced TRAP-positive multinucleated cells. The receptor-associated protein, an antagonist of the low-density lipoprotein (LDL) receptor family, blocked the effects of F-spondin on M-CSF-induced migration. The suppressive effect of F-spondin on M-CSF-induced cell migration was blocked by knockdown of LDL receptor-related protein 8 (LRP8), a member of the LDL receptor family. Our findings suggest that F-spondin downregulates recruitment to the root side of periodontal tissue via LRP8 and inhibits differentiation of osteoclastic precursors. It is suggested that F-spondin is essential to protect the root surface from resorption.

Aptamer-Mediated Codelivery of Doxorubicin and NF-κB Decoy Enhances Chemosensitivity of Pancreatic Tumor Cells

PubMed Central

Porciani, David; Tedeschi, Lorena; Marchetti, Laura; Citti, Lorenzo; Piazza, Vincenzo; Beltram, Fabio; Signore, Giovanni

2015-01-01

Aptamers able to bind efficiently cell-surface receptors differentially expressed in tumor and in healthy cells are emerging as powerful tools to perform targeted anticancer therapy. Here, we present a novel oligonucleotide chimera, composed by an RNA aptamer and a DNA decoy. Our assembly is able to (i) target tumor cells via an antitransferrin receptor RNA aptamer and (ii) perform selective codelivery of a chemotherapeutic drug (Doxorubicin) and of an inhibitor of a cell-survival factor, the nuclear factor κB decoy oligonucleotide. Both payloads are released under conditions found in endolysosomal compartments (low pH and reductive environment). Targeting and cytotoxicity of the oligonucleotidic chimera were assessed by confocal microscopy, cell viability, and Western blot analysis. These data indicated that the nuclear factor κB decoy does inhibit nuclear factor κB activity and ultimately leads to an increased therapeutic efficacy of Doxorubicin selectively in tumor cells. PMID:25919089

Human Umbilical Cord Perivascular Cells Exhibited Enhanced Migration Capacity towards Hepatocellular Carcinoma in Comparison with Bone Marrow Mesenchymal Stromal Cells: A Role for Autocrine Motility Factor Receptor

PubMed Central

Aquino, Jorge B.; Malvicini, Mariana; Bolontrade, Marcela; Podhajcer, Osvaldo; Garcia, Mariana G.; Mazzolini, Guillermo

2014-01-01

Hepatocellular carcinoma (HCC) is the third cause of cancer-related death worldwide. Unfortunately, the incidence and mortality associated with HCC are increasing. Therefore, new therapeutic strategies are urgently needed and the use of mesenchymal stromal cells (MSCs) as carrier of therapeutic genes is emerging as a promising option. Different sources of MSCs are being studied for cell therapy and bone marrow-derived cells are the most extensively explored; however, birth associated-tissues represent a very promising source. The aim of this work was to compare the in vitro and in vivo migration capacity between bone marrow MSCs (BM-MSCs) and human umbilical cord perivascular cells (HUCPVCs) towards HCC. We observed that HUCPVCs presented higher in vitro and in vivo migration towards factors released by HCC. The expression of autocrine motility factor (AMF) receptor, genes related with the availability of the receptor on the cell surface (caveolin-1 and -2) and metalloproteinase 3, induced by the receptor activation and important for cell migration, was increased in HUCPVCs. The chemotactic response towards recombinant AMF was increased in HUCPVCs compared to BM-MSCs, and its inhibition in the conditioned medium from HCC induced higher decrease in HUCPVC migration than in BM-MSC. Our results indicate that HUCPVCs could be a useful cellular source to deliver therapeutic genes to HCC. PMID:25147818

Human umbilical cord perivascular cells exhibited enhanced migration capacity towards hepatocellular carcinoma in comparison with bone marrow mesenchymal stromal cells: a role for autocrine motility factor receptor.

PubMed

Bayo, Juan; Fiore, Esteban; Aquino, Jorge B; Malvicini, Mariana; Rizzo, Manglio; Peixoto, Estanislao; Alaniz, Laura; Piccioni, Flavia; Bolontrade, Marcela; Podhajcer, Osvaldo; Garcia, Mariana G; Mazzolini, Guillermo

2014-01-01

Hepatocellular carcinoma (HCC) is the third cause of cancer-related death worldwide. Unfortunately, the incidence and mortality associated with HCC are increasing. Therefore, new therapeutic strategies are urgently needed and the use of mesenchymal stromal cells (MSCs) as carrier of therapeutic genes is emerging as a promising option. Different sources of MSCs are being studied for cell therapy and bone marrow-derived cells are the most extensively explored; however, birth associated-tissues represent a very promising source. The aim of this work was to compare the in vitro and in vivo migration capacity between bone marrow MSCs (BM-MSCs) and human umbilical cord perivascular cells (HUCPVCs) towards HCC. We observed that HUCPVCs presented higher in vitro and in vivo migration towards factors released by HCC. The expression of autocrine motility factor (AMF) receptor, genes related with the availability of the receptor on the cell surface (caveolin-1 and -2) and metalloproteinase 3, induced by the receptor activation and important for cell migration, was increased in HUCPVCs. The chemotactic response towards recombinant AMF was increased in HUCPVCs compared to BM-MSCs, and its inhibition in the conditioned medium from HCC induced higher decrease in HUCPVC migration than in BM-MSC. Our results indicate that HUCPVCs could be a useful cellular source to deliver therapeutic genes to HCC.

Vascular Endothelial Growth Factor and Angiopoietin are Required for Prostate Regeneration.

PubMed Central

Wang, Gui-min; Kovalenko, Bruce; Huang, Yili; Moscatelli, David

2007-01-01

BACKGROUND The regulation of the prostate size by androgens may be partly the result of androgen effects on the prostatic vasculature. We examined the effect of changes in androgen levels on the expression of a variety of angiogenic factors in the mouse prostate and determined if vascular endothelial growth factor (VEGF)-A and the angiopoietins are involved in the vascular response to androgens. METHODS Expression of angiogenic factors in prostate was quantitated using real-time PCR at different times after castration and after administration of testosterone to castrated mice. Angiopoietins were localized in prostate by immunohistochemistry and in situ hybridization. The roles of VEGF and the angiopoietins in regeneration of the prostate were examined in mice inoculated with cells expressing soluble VEGF receptor-2 or soluble Tie-2. RESULTS Castration resulted in a decrease in VEGF-A, VEGF-B, VEGF-C, placenta growth factor, FGF-2, and FGF-8 expression after one day. In contrast, VEGF-D mRNA levels increased. No changes in angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), hepatocyte growth factor, VEGF receptor-1, VEGF receptor-2 or tie-2 mRNA levels were observed. Administration of testosterone to castrated mice had the opposite effect on expression of these angiogenic factors. Ang-2 was expressed predominately in prostate epithelial cells whereas Ang-1 was expressed in epithelium and smooth muscle. Inoculation of mice with cells expressing soluble VEGF receptor-2 or Tie-2 blocked the increase in vascular density normally observed after administration of testosterone to castrated mice. The soluble receptors also blocked the increase in prostate weight and proliferation of prostatic epithelial cells. CONCLUSION VEGF-A and angiopoietins are required for the vascular response to androgens and for the ability of the prostate to regenerate in response to androgens. PMID:17221843

Coordinate regulation of estrogen-mediated fibronectin matrix assembly and epidermal growth factor receptor transactivation by the G protein-coupled receptor, GPR30.

PubMed

Quinn, Jeffrey A; Graeber, C Thomas; Frackelton, A Raymond; Kim, Minsoo; Schwarzbauer, Jean E; Filardo, Edward J

2009-07-01

Estrogen promotes changes in cytoskeletal architecture not easily attributed to the biological action of estrogen receptors, ERalpha and ERbeta. The Gs protein-coupled transmembrane receptor, GPR30, is linked to specific estrogen binding and rapid estrogen-mediated release of heparin-bound epidermal growth factor. Using marker rescue and dominant interfering mutant strategies, we show that estrogen action via GPR30 promotes fibronectin (FN) matrix assembly by human breast cancer cells. Stimulation with 17beta-estradiol or the ER antagonist, ICI 182, 780, results in the recruitment of FN-engaged integrin alpha5beta1 conformers to fibrillar adhesions and the synthesis of FN fibrils. Concurrent with this cellular response, GPR30 promotes the formation of Src-dependent, Shc-integrin alpha5beta1 complexes. Function-blocking antibodies directed against integrin alpha5beta1 or soluble Arg-Gly-Asp peptide fragments derived from FN specifically inhibited GPR30-mediated epidermal growth factor receptor transactivation. Estrogen-mediated FN matrix assembly and epidermal growth factor receptor transactivation were similarly disrupted in integrin beta1-deficient GE11 cells, whereas reintroduction of integrin beta1 into GE11 cells restored these responses. Mutant Shc (317Y/F) blocked GPR30-induced FN matrix assembly and tyrosyl phosphorylation of erbB1. Interestingly, relative to recombinant wild-type Shc, 317Y/F Shc was more readily retained in GPR30-induced integrin alpha5beta1 complexes, yet this mutant did not prevent endogenous Shc-integrin alpha5beta1 complex formation. Our results suggest that GPR30 coordinates estrogen-mediated FN matrix assembly and growth factor release in human breast cancer cells via a Shc-dependent signaling mechanism that activates integrin alpha5beta1.

Isolated dorsal root ganglion neurones inhibit receptor-dependent adenylyl cyclase activity in associated glial cells

PubMed Central

Ng, KY; Yeung, BHS; Wong, YH; Wise, H

2013-01-01

Background and Purpose Hyper-nociceptive PGE2 EP4 receptors and prostacyclin (IP) receptors are present in adult rat dorsal root ganglion (DRG) neurones and glial cells in culture. The present study has investigated the cell-specific expression of two other Gs-protein coupled hyper-nociceptive receptor systems: β-adrenoceptors and calcitonin gene-related peptide (CGRP) receptors in isolated DRG cells and has examined the influence of neurone–glial cell interactions in regulating adenylyl cyclase (AC) activity. Experimental Approach Agonist-stimulated AC activity was determined in mixed DRG cell cultures from adult rats and compared with activity in DRG neurone-enriched cell cultures and pure DRG glial cell cultures. Key Results Pharmacological analysis showed the presence of Gs-coupled β2-adrenoceptors and CGRP receptors, but not β1-adrenoceptors, in all three DRG cell preparations. Agonist-stimulated AC activity was weakest in DRG neurone-enriched cell cultures. DRG neurones inhibited IP receptor-stimulated glial cell AC activity by a process dependent on both cell–cell contact and neurone-derived soluble factors, but this is unlikely to involve purine or glutamine receptor activation. Conclusions and Implications Gs-coupled hyper-nociceptive receptors are readily expressed on DRG glial cells in isolated cell cultures and the activity of CGRP, EP4 and IP receptors, but not β2-adrenoceptors, in glial cells is inhibited by DRG neurones. Studies using isolated DRG cells should be aware that hyper-nociceptive ligands may stimulate receptors on glial cells in addition to neurones, and that variable numbers of neurones and glial cells will influence absolute measures of AC activity and affect downstream functional responses. PMID:22924655

Dissecting Bacterial Cell Wall Entry and Signaling in Eukaryotic Cells: an Actin-Dependent Pathway Parallels Platelet-Activating Factor Receptor-Mediated Endocytosis.

PubMed

Loh, Lip Nam; Gao, Geli; Tuomanen, Elaine I

2017-01-03

The Gram-positive bacterial cell wall (CW) peptidoglycan-teichoic acid complex is released into the host environment during bacterial metabolism or death. It is a highly inflammatory Toll-like receptor 2 (TLR2) ligand, and previous in vivo studies have demonstrated its ability to recapitulate pathological features of pneumonia and meningitis. We report that an actin-dependent pathway is involved in the internalization of the CW by epithelial and endothelial cells, in addition to the previously described platelet-activating factor receptor (PAFr)-dependent uptake pathway. Unlike the PAFr-dependent pathway, which is mediated by clathrin and dynamin and does not lead to signaling, the alternative pathway is sensitive to 5-(N-ethyl-N-isopropyl) amiloride (EIPA) and engenders Rac1, Cdc42, and phosphatidylinositol 3-kinase (PI3K) signaling. Upon internalization by this macropinocytosis-like pathway, CW is trafficked to lysosomes. Intracellular CW trafficking is more complex than previously recognized and suggests multiple points of interaction with and without innate immune signaling. Streptococcus pneumoniae is a major human pathogen infecting the respiratory tract and brain. It is an established model organism for understanding how infection injures the host. During infection or bacterial growth, bacteria shed their cell wall (CW) into the host environment and trigger inflammation. A previous study has shown that CW enters and crosses cell barriers by interacting with a receptor on the surfaces of host cells, termed platelet-activating factor receptor (PAFr). In the present study, by using cells that are depleted of PAFr, we identified a second pathway with features of macropinocytosis, which is a receptor-independent fluid uptake mechanism by cells. Each pathway contributes approximately the same amount of cell wall trafficking, but the PAFr pathway is silent, while the new pathway appears to contribute to the host inflammatory response to CW insult. Copyright © 2017 Loh et al.

Neomycin is a platelet-derived growth factor (PDGF) antagonist that allows discrimination of PDGF alpha- and beta-receptor signals in cells expressing both receptor types.

PubMed

Vassbotn, F S; Ostman, A; Siegbahn, A; Holmsen, H; Heldin, C H

1992-08-05

The aminoglycoside neomycin has recently been found to affect certain platelet-derived growth factor (PDGF) responses in C3H/10T1/2 C18 fibroblasts. Using porcine aortic endothelial cells transfected with PDGF alpha- or beta-receptors, we explored the possibility that neomycin interferes with the interaction between the different PDGF isoforms and their receptors. We found that neomycin (5 mM) inhibited the binding of 125I-PDGF-BB to the alpha-receptor with only partial effect on the binding of 125I-PDGF-AA; in contrast, the binding of 125I-PDGF-BB to the beta-receptor was not affected by the aminoglycoside. Scatchard analyses showed that neomycin (5 mM) decreased the number of binding sites for PDGF-BB on alpha-receptor-expressing cells by 87%. Together with cross-competition studies with 125I-labeled PDGF homodimers, the effect of neomycin indicates that PDGF-AA and PDGF-BB bind to both common and unique structures on the PDGF alpha-receptor. Neomycin specifically inhibited the autophosphorylation of the alpha-receptor by PDGF-BB, with less effect on the phosphorylation induced by PDGF-AA and no effect on the phosphorylation of the beta-receptor by PDGF-BB. Thus, neomycin is a PDGF isoform- and receptor-specific antagonist that provides a possibility to compare the signal transduction pathways of alpha- and beta-receptors in cells expressing both receptor types. This approach was used to show that activation of PDGF beta-receptors by PDGF-BB mediated a chemotactic response in human fibroblasts, whereas activation of alpha-receptors by the same ligand inhibited chemotaxis.

Developmentally Regulated Expression of the Nerve Growth Factor Receptor Gene in the Periphery and Brain

NASA Astrophysics Data System (ADS)

Buck, C. R.; Martinez, Humberto J.; Black, Ira B.; Chao, Moses V.

1987-05-01

Nerve growth factor (NGF) regulates development and maintenance of function of peripheral sympathetic and sensory neurons. A potential role for the trophic factor in brain has been detected only recently. The ability of a cell to respond to NGF is due, in part, to expression of specific receptors on the cell surface. To study tissue-specific expression of the NGF receptor gene, we have used sensitive cRNA probes for detection of NGF receptor mRNA. Our studies indicate that the receptor gene is selectively and specifically expressed in sympathetic (superior cervical) and sensory (dorsal root) ganglia in the periphery, and by the septum-basal forebrain centrally, in the neonatal rat in vivo. Moreover, examination of tissues from neonatal and adult rats reveals a marked reduction in steady-state NGF receptor mRNA levels in sensory ganglia. In contrast, a 2- to 4-fold increase was observed in the basal forebrain and in the sympathetic ganglia over the same time period. Our observations suggest that NGF receptor mRNA expression is developmentally regulated in specific areas of the nervous system in a differential fashion.

Role of Epidermal Growth Factor Receptors and Their Ligands in Normal Mammary Epithelial and Breast Cancer Cells

DTIC Science & Technology

1997-07-01

have an estrogen receptor and progesterone receptor negative phenotype, high proliferation rates, poor response to endocrine therapy, and reduced...mitogenic effects of estrogen, progesterone and prolactin in breast cancer cell lines (3), and part of the growth promoting effects of an activated ras...of the cases (51,52), and an inverse relationship with estrogen and progesterone receptors; in such tumors, a poor response to endocrine therapy

CXCR-4 expression by circulating endothelial progenitor cells and SDF-1 serum levels are elevated in septic patients.

PubMed

Patry, Christian; Stamm, Daniela; Betzen, Christian; Tönshoff, Burkhard; Yard, Benito A; Beck, Grietje Ch; Rafat, Neysan

2018-01-01

Endothelial progenitor cell (EPC) numbers are increased in septic patients and correlate with survival. In this study, we investigated, whether surface expression of chemokine receptors and other receptors important for EPC homing is upregulated by EPC from septic patients and if this is associated with clinical outcome. Peripheral blood mononuclear cells from septic patients ( n  = 30), ICU control patients ( n  = 11) and healthy volunteers ( n  = 15) were isolated by Ficoll density gradient centrifugation. FACS-analysis was used to measure the expression of the CXC motif chemokine receptors (CXCR)-2 and - 4, the receptor for advanced glycation endproducts (RAGE) and the stem cell factor receptor c-Kit. Disease severity was assessed via the Simplified Acute Physiology Score (SAPS) II. The serum concentrations of vascular endothelial growth factor (VEGF), stromal cell-derived factor (SDF)-1α and angiopoietin (Ang)-2 were determined with Enzyme linked Immunosorbent Assays. EPC from septic patients expressed significantly more CXCR-4, c-Kit and RAGE compared to controls and were associated with survival-probability. Significantly higher serum concentrations of VEGF, SDF-1α and Ang-2 were found in septic patients. SDF-1α showed a significant association with survival. Our data suggest that SDF-1α and CXCR-4 signaling could play a crucial role in EPC homing in the course of sepsis.

Chimeras of the native form or achondroplasia mutant (G375C) of human fibroblast growth factor receptor 3 induce ligand-dependent differentiation of PC12 cells.

PubMed Central

Thompson, L M; Raffioni, S; Wasmuth, J J; Bradshaw, R A

1997-01-01

Mutations in the gene for human fibroblast growth factor receptor 3 (hFGFR3) cause a variety of skeletal dysplasias, including the most common genetic form of dwarfism, achondroplasia (ACH). Evidence indicates that these phenotypes are not due to simple haploinsufficiency of FGFR3 but are more likely related to a role in negatively regulating skeletal growth. The effects of one of these mutations on FGFR3 signaling were examined by constructing chimeric receptors composed of the extracellular domain of human platelet-derived growth factor receptor beta (hPDGFR beta) and the transmembrane and intracellular domains of hFGFR3 or of an ACH (G375C) mutant. Following stable transfection in PC12 cells, which lack platelet-derived growth factor (PDGF) receptors, all clonal cell lines, with either type of chimera, showed strong neurite outgrowth in the presence of PDGF but not in its absence. Antiphosphotyrosine immunoblots showed ligand-dependent autophosphorylation, and both receptor types stimulated strong phosphorylation of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase, an event associated with the differentiative response of these cells. In addition, ligand-dependent phosphorylation of phospholipase Cgamma and Shc was also observed. All of these responses were comparable to those observed from ligand activation, such as by nerve growth factor, of the native PC12 cells used to prepare the stable transfectants. The cells with the chimera bearing the ACH mutation were more rapidly responsive to ligand with less sustained MAPK activation, indicative of a preactivated or primed condition and consistent with the view that these mutations weaken ligand control of FGFR3 function. However, the full effect of the mutation likely depends in part on structural features of the extracellular domain. Although FGFR3 has been suggested to act as a negative regulator of long-bone growth in chrondrocytes, it produces differentiative signals similar to those of FGFR1, to which only positive effects have been ascribed, in PC12 cells. Therefore, its regulatory effects on bone growth likely result from cellular contexts and not the induction of a unique FGFR3 signaling pathway. PMID:9199352

RNA Expression Profiling Reveals Differentially Regulated Growth Factor and Receptor Expression in Redirected Cancer Cells.

PubMed

Schmucker, Hannah S; Park, Jang Pyo; Coissieux, Marie-May; Bentires-Alj, Mohamed; Feltus, F Alex; Booth, Brian W

2017-05-01

Tumorigenic cells can be redirected to adopt a normal phenotype when transplanted into cleared mammary fat pads of juvenile female mice in specific ratios with normal epithelial cells. The redirected tumorigenic cells enter stem cell niches and provide progeny that differentiate into all mammary epithelial subtypes. We have developed an in vitro model that mimics the in vivo phenomenon. The shift in phenotype to redirection should be accomplished through a return to a normal gene expression state. To measure this shift, we interrogated the transcriptome of various in vitro model states in search for casual genes. For this study, expression of growth factors, cytokines, and their associated receptors was examined. In all, we queried 251 growth factor and cytokine-related genes. We found numerous growth factor and cytokine genes whose expression levels switched from expression levels seen in cancer cells to expression levels observed in normal cells. The comparisons of gene expression between normal mammary epithelial cells, tumor-derived cells, and redirected cancer cells have revealed insight into active and inactive growth factors and cytokines in cancer cell redirection.

Carboxyl‐terminal Heparin‐binding Fragments of Platelet Factor 4 Retain the Blocking Effect on the Receptor Binding of Basic Fibroblast Growth Factor

PubMed Central

Waki, Michinori; Ohno, Motonori; Kuwano, Michihiko; Sakata, Toshiie

1993-01-01

Platelet factor 4 (PF‐4) blocks the binding of basic fibroblast growth factor (bFGF) to its receptor. In the present study, we constructed carboxyl‐terminal fragments, which represent the heparin‐binding region of the PF‐4 molecule, and examined whether these synthetic peptides retain the blocking effects on the receptor binding of bFGF. Synthetic peptides inhibited the receptor binding of bFGF. Furthermore, they inhibited the migration and tube formation of bovine capillary endothelial cells in culture (these phenomena are dependent on endogenous bFGF). PMID:8320164

Modification of cytokine-induced killer cells with chimeric antigen receptors (CARs) enhances antitumor immunity to epidermal growth factor receptor (EGFR)-positive malignancies.

PubMed

Ren, Xuequn; Ma, Wanli; Lu, Hong; Yuan, Lei; An, Lei; Wang, Xicai; Cheng, Guanchang; Zuo, Shuguang

2015-12-01

Epidermal growth factor receptor (EGFR, ErbB1, Her-1) is a cell surface molecule overexpressing in a variety of human malignancies and, thus, is an excellent target for immunotherapy. Immunotherapy targeting EGFR-overexpressing malignancies using genetically modified immune effector cells is a novel and promising approach. In the present study, we have developed an adoptive cellular immunotherapy strategy based on the chimeric antigen receptor (CAR)-modified cytokine-induced killer (CAR-CIK) cells specific for the tumor cells expressing EGFR. To generate CAR-CIK cells, a lentiviral vector coding the EGFR-specific CAR was constructed and transduced into the CIK cells. The CAR-CIK cells showed significantly enhanced cytotoxicity and increased production of cytokines IFN-γ and IL-2 when co-cultured with EGFR-positive cancer cells. In tumor xenografts, adoptive immunotherapy of CAR-CIK cells could inhibit tumor growth and prolong the survival of EGFR-overexpressing human tumor xenografts. Moreover, tumor growth inhibition and prolonged survival in mice with EGFR(+) human cancer were associated with the increased persistence of CAR-CIK cells in vivo. Our study indicates that modification with EGFR-specific CAR strongly enhances the antitumor activity of the CIK cells against EGFR-positive malignancies.

The C-type Lectin Langerin Functions as a Receptor for Attachment and Infectious Entry of Influenza A Virus

PubMed Central

Ng, Wy Ching; Londrigan, Sarah L.; Nasr, Najla; Cunningham, Anthony L.; Turville, Stuart; Brooks, Andrew G.

2015-01-01

ABSTRACT It is well established that influenza A virus (IAV) attachment to and infection of epithelial cells is dependent on sialic acid (SIA) at the cell surface, although the specific receptors that mediate IAV entry have not been defined and multiple receptors may exist. Lec2 Chinese hamster ovary (CHO) cells are SIA deficient and resistant to IAV infection. Here we demonstrate that the expression of the C-type lectin receptor langerin in Lec2 cells (Lec2-Lg) rendered them permissive to IAV infection, as measured by replication of the viral genome, transcription of viral mRNA, and synthesis of viral proteins. Unlike SIA-dependent infection of parental CHO cells, IAV attachment and infection of Lec2-Lg cells was mediated via lectin-mediated recognition of mannose-rich glycans expressed by the viral hemagglutinin glycoprotein. Lec2 cells expressing endocytosis-defective langerin bound IAV efficiently but remained resistant to IAV infection, confirming that internalization via langerin was essential for infectious entry. Langerin-mediated infection of Lec2-Lg cells was pH and dynamin dependent, occurred via clathrin- and caveolin-mediated endocytic pathways, and utilized early (Rab5+) but not late (Rab7+) endosomes. This study is the first to demonstrate that langerin represents an authentic receptor that binds and internalizes IAV to facilitate infection. Moreover, it describes a unique experimental system to probe specific pathways and compartments involved in infectious entry following recognition of IAV by a single cell surface receptor. IMPORTANCE On the surface of host cells, sialic acid (SIA) functions as the major attachment factor for influenza A viruses (IAV). However, few studies have identified specific transmembrane receptors that bind and internalize IAV to facilitate infection. Here we identify human langerin as a transmembrane glycoprotein that can act as an attachment factor and a bone fide endocytic receptor for IAV infection. Expression of langerin by an SIA-deficient cell line resistant to IAV rendered cells permissive to infection. As langerin represented the sole receptor for IAV infection in this system, we have defined the pathways and compartments involved in infectious entry of IAV into cells following recognition by langerin. PMID:26468543

A c-fms tyrosine kinase inhibitor, Ki20227, suppresses osteoclast differentiation and osteolytic bone destruction in a bone metastasis model.

PubMed

Ohno, Hiroaki; Kubo, Kazuo; Murooka, Hideko; Kobayashi, Yoshiko; Nishitoba, Tsuyoshi; Shibuya, Masabumi; Yoneda, Toshiyuki; Isoe, Toshiyuki

2006-11-01

In bone metastatic lesions, osteoclasts play a key role in the development of osteolysis. Previous studies have shown that macrophage colony-stimulating factor (M-CSF) is important for the differentiation of osteoclasts. In this study, we investigated whether an inhibitor of M-CSF receptor (c-Fms) suppresses osteoclast-dependent osteolysis in bone metastatic lesions. We developed small molecule inhibitors against ligand-dependent phosphorylation of c-Fms and examined the effects of these compounds on osteolytic bone destruction in a bone metastasis model. We discovered a novel quinoline-urea derivative, Ki20227 (N-{4-[(6,7-dimethoxy-4-quinolyl)oxy]-2-methoxyphenyl}-N'-[1-(1,3-thiazole-2-yl)ethyl]urea), which is a c-Fms tyrosine kinase inhibitor. The IC(50)s of Ki20227 to inhibit c-Fms, vascular endothelial growth factor receptor-2 (KDR), stem cell factor receptor (c-Kit), and platelet-derived growth factor receptor beta were found to be 2, 12, 451, and 217 nmol/L, respectively. Ki20227 did not inhibit other kinases tested, such as fms-like tyrosine kinase-3, epidermal growth factor receptor, or c-Src (c-src proto-oncogene product). Ki20227 was also found to inhibit the M-CSF-dependent growth of M-NFS-60 cells but not the M-CSF-independent growth of A375 human melanoma cells in vitro. Furthermore, in an osteoclast-like cell formation assay using mouse bone marrow cells, Ki20227 inhibited the development of tartrate-resistant acid phosphatase-positive osteoclast-like cells in a dose-dependent manner. In in vivo studies, oral administration of Ki20227 suppressed osteoclast-like cell accumulation and bone resorption induced by metastatic tumor cells in nude rats following intracardiac injection of A375 cells. Moreover, Ki20227 decreased the number of tartrate-resistant acid phosphatase-positive osteoclast-like cells on bone surfaces in ovariectomized (ovx) rats. These findings suggest that Ki20227 inhibits osteolytic bone destruction through the suppression of M-CSF-induced osteoclast accumulation in vivo. Therefore, Ki20227 may be a useful therapeutic agent for osteolytic disease associated with bone metastasis and other bone diseases.

Steroid hormone receptor status defines the MMTV promoter chromatin structure in vivo.

PubMed

Archer, T K; Fryer, C J; Lee, H L; Zaniewski, E; Liang, T; Mymryk, J S

1995-06-01

The ability to respond to small signalling molecules such as steroid hormones is important for many physiological processes. Steroid hormones act through a group of high affinity receptors that regulate transcription by binding to hormone response elements (HREs) located within the promoters of target genes, which themselves are organized with nuclear proteins to form chromatin. To dissect the mechanisms(s) of steroid hormone action we have used the steroid inducible mouse mammary tumor virus (MMTV) promoter as a model system. The MMTV promoter is assembled into a phased array of nucleosomes that are specifically positioned in rodent cells. Induction of transcription by glucocorticoids is accompanied by the appearance of a hypersensitive region in the proximal promoter which allows the hormone dependent assembly of a preinitiation complex including transcription factors such as nuclear factor 1 (NF1) and the octamer transcription factor (OTF). Surprisingly, when introduced by transient transfection, the progesterone receptor (PR) is unable to activate this promoter in vivo, a finding that may result from its inability to alter MMTV promoter chromatin. In an attempt to investigate the failure of the PR to activate the promoter, we have stably introduced the MMTV promoter into human T47D breast cancer cells that express high levels of the PR. In contrast to what has been observed previously in rodent cells, the MMTV templates resident in human breast cancer cells adopt a novel and constitutively open chromatin structure. The constitutively open chromatin structure is accompanied by the hormone independent loading of transcription factors including the PR and NF1. In T47D cells that stably express the glucocorticoid receptor, the MMTV promoter responds to glucocorticoids, but not progestins, and displays glucocorticoid induced restriction enzyme hypersensitivity and transcription factor loading. These findings suggest that the organization of the MMTV chromatin structure is dependent upon the cell type and receptor status of the recipient cell into which the MMTV promoter is stably introduced.

Soluble TL1A is sufficient for activation of death receptor 3.

PubMed

Bittner, Sebastian; Knoll, Gertrud; Füllsack, Simone; Kurz, Maria; Wajant, Harald; Ehrenschwender, Martin

2016-01-01

Death receptor 3 (DR3) is a typical member of the tumor necrosis factor receptor family, and was initially identified as a T-cell co-stimulatory molecule. However, further studies revealed a more complex and partly dichotomous role for DR3 and its ligand TL1A under (patho)physiological conditions. TL1A and DR3 are not only a driving force in the development of autoimmune and inflammatory diseases, but also play an important role in counteracting these processes through an increase in the number of regulatory T cells. Ligands of the tumor necrosis factor family typically occur in two forms, membrane-bound and soluble, that can differ strikingly with respect to their efficacy in activating their corresponding receptor(s). Ligand-based approaches to activate the TL1A-DR3 pathway therefore require understanding of the molecular prerequisites of TL1A-based DR3 activation. To date, this has not been addressed. Here, we show that recombinant soluble trimeric TL1A is fully sufficient to strongly activate DR3-associated pro- and anti-apoptotic signaling pathways. In contrast to the TRAIL death receptors, which are much better activated by soluble TRAIL upon secondary ligand oligomerization, but similarly to the death receptor tumor necrosis factor receptor 1, DR3 is efficiently activated by soluble TL1A trimers. Additionally, we have measured the affinity of TL1A-DR3 interaction in a cell-based system, and demonstrated TL1A-induced DR3 internalization. Identification of DR3 as a tumor necrosis factor receptor that responds to soluble ligand trimers without further oligomerization provides a basis for therapeutic exploitation of the TL1A-DR3 pathway. © 2015 FEBS.

Src family kinase expression and subcellular localization in macrophages: implications for their role in CSF-1-induced macrophage migration.

PubMed

Dwyer, Amy R; Mouchemore, Kellie A; Steer, James H; Sunderland, Andrew J; Sampaio, Natalia G; Greenland, Eloise L; Joyce, David A; Pixley, Fiona J

2016-07-01

A major role of colony-stimulating factor-1 is to stimulate the differentiation of mononuclear phagocytic lineage cells into adherent, motile, mature macrophages. The colony-stimulating factor-1 receptor transduces colony-stimulating factor-1 signaling, and we have shown previously that phosphatidylinositol 3-kinase p110δ is a critical mediator of colony-stimulating factor-1-stimulated motility through the colony-stimulating factor-1 receptor pY721 motif. Src family kinases are also implicated in the regulation of macrophage motility and in colony-stimulating factor-1 receptor signaling, although functional redundancy of the multiple SFKs expressed in macrophages makes it challenging to delineate their specific functions. We report a comprehensive analysis of individual Src family kinase expression in macrophage cell lines and primary macrophages and demonstrate colony-stimulating factor-1-induced changes in Src family kinase subcellular localization, which provides clues to their distinct and redundant functions in macrophages. Moreover, expression of individual Src family kinases is both species specific and dependent on colony-stimulating factor-1-induced macrophage differentiation. Hck associated with the activated colony-stimulating factor-1 receptor, whereas Lyn associated with the receptor in a constitutive manner. Consistent with this, inhibitor studies revealed that Src family kinases were important for both colony-stimulating factor-1 receptor activation and colony-stimulating factor-1-induced macrophage spreading, motility, and invasion. Distinct colony-stimulating factor-1-induced changes in the subcellular localization of individual SFKs suggest specific roles for these Src family kinases in the macrophage response to colony-stimulating factor-1. © Society for Leukocyte Biology.

Decreased numbers of chemotactic factor receptors in chronic neutropenia with defective chemotaxis: spontaneous recovery from the neutrophil abnormalities during early childhood

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yasui, K.; Yamazaki, M.; Miyagawa, Y.

Childhood chronic neutropenia with decreased numbers of chemotactic factor receptors as well as defective chemotaxis was first demonstrated in an 8-month-old girl. Chemotactic factor receptors on neutrophils were assayed using tritiated N-formyl-methionyl-leucyl-phenylalanine (/sup 3/H-FMLP). The patient's neutrophils had decreased numbers of the receptors: numbers of the receptors were 20,000 (less than 3 SD) as compared with those of control cells of 52,000 +/- 6000 (mean +/- SD) (n = 10). The neutropenia disappeared spontaneously by 28 months of age parallel with the improvement of chemotaxis and increase in numbers of chemotactic factor receptors. These results demonstrate a transient decrease ofmore » neutrophil chemotactic factor receptors as one of the pathophysiological bases of a transient defect of neutrophil chemotaxis in this disorder.« less

Functional characterization of an alpha-factor-like Sordaria macrospora peptide pheromone and analysis of its interaction with its cognate receptor in Saccharomyces cerevisiae.

PubMed

Mayrhofer, Severine; Pöggeler, Stefanie

2005-04-01

The homothallic filamentous ascomycete Sordaria macrospora possesses genes which are thought to encode two pheromone precursors and two seven-transmembrane pheromone receptors. The pheromone precursor genes are termed ppg1 and ppg2. The putative products derived from the gene sequence show structural similarity to the alpha-factor precursors and a-factor precursors of the yeast Saccharomyces cerevisiae. Likewise, sequence similarity has been found between the putative products of the pheromone receptor genes pre2 and pre1 and the S. cerevisiae Ste2p alpha-factor receptor and Ste3p a-factor receptor, respectively. To investigate whether the alpha-factor-like pheromone-receptor pair of S. macrospora is functional, a heterologous yeast assay was used. Our results show that the S. macrospora alpha-factor-like pheromone precursor PPG1 is processed into an active pheromone by yeast MATalpha cells. The S. macrospora PRE2 protein was demonstrated to be a peptide pheromone receptor. In yeast MATa cells lacking the endogenous Ste2p receptor, the S. macrospora PRE2 receptor facilitated all aspects of the pheromone response. Using a synthetic peptide, we can now predict the sequence of one active form of the S. macrospora peptide pheromone. We proved that S. macrospora wild-type strains secrete an active pheromone into the culture medium and that disruption of the ppg1 gene in S. macrospora prevents pheromone production. However, loss of the ppg1 gene does not affect vegetative growth or fertility. Finally, we established the yeast assay as an easy and useful system for analyzing pheromone production in developmental mutants of S. macrospora.

In vitro long-term culture of human primitive hematopoietic cells supported by murine stromal cell line MS-5.

PubMed

Nishi, N; Ishikawa, R; Inoue, H; Nishikawa, M; Yoneya, T; Kakeda, M; Tsumura, H; Ohashi, H; Mori, K J

1997-04-01

When Lin-CD34+CD38- cells from normal human cord blood were cocultured with MS-5, colony forming cells were maintained for over 8 weeks. Prevention of contact between MS-5 and Lin-CD34+CD38- cells by using a membrane filter was negligible for this activity, indicating that the activity of MS-5 on human primitive hematopoietic cells may be due to soluble factor(s) secreted from MS-5. We tried to purify this activity by a [3H]TdR incorporation assay. The activity was found in 150 kD fraction and was neutralized with anti-mSCF (stem cell factor) antibody. Another 20-30 kD fraction synergized with mSCF to stimulate the growth of Lin-CD34+CD38- cells but failed alone. This fraction supported the growth of the G-CSF (granulocyte-colony stimulating factor)-dependent cell line FD/GR3, FDC-P2 transfected with mG-CSF receptor cDNA. This synergy was canceled in the presence of soluble mG-CSF receptor. Addition of anti-mSCF antibody and soluble mG-CSF receptor to the culture completely abrogated the activity of MS-5-culture supernatant. These results indicate the activity of MS-5 on Lin-CD34+CD38- cells is due to synergistic effect of mSCF and mG-CSF.

Near Infrared Optical Visualization of Epidermal Growth Factor Receptors Levels in COLO205 Colorectal Cell Line, Orthotopic Tumor in Mice and Human Biopsies

PubMed Central

Cohen, Gadi; Lecht, Shimon; Oron-Herman, Mor; Momic, Tatjana; Nissan, Aviram; Lazarovici, Philip

2013-01-01

In this study, we present the applicability of imaging epidermal growth factor (EGF) receptor levels in preclinical models of COLO205 carcinoma cells in vitro, mice with orthotopic tumors and ex vivo colorectal tumor biopsies, using EGF-labeled with IRDye800CW (EGF-NIR). The near infrared (NIR) bio-imaging of COLO205 cultures indicated specific and selective binding, reflecting EGF receptors levels. In vivo imaging of tumors in mice showed that the highest signal/background ratio between tumor and adjacent tissue was achieved 48 hours post-injection. Dissected colorectal cancer tissues from different patients demonstrated ex vivo specific imaging using the NIR bio-imaging platform of the heterogeneous distributed EGF receptors. Moreover, in the adjacent gastrointestinal tissue of the same patients, which by Western blotting was demonstrated as EGF receptor negative, no labeling with EGF-NIR probe was detected. Present results support the concept of tumor imaging by measuring EGF receptor levels using EGF-NIR probe. This platform is advantageous for EGF receptor bio-imaging of the NCI-60 recommended panel of tumor cell lines including 6–9 colorectal cell lines, since it avoids radioactive probes and is appropriate for use in the clinical setting using NIR technologies in a real-time manner. PMID:23857061

Near infrared optical visualization of epidermal growth factor receptors levels in COLO205 colorectal cell line, orthotopic tumor in mice and human biopsies.

PubMed

Cohen, Gadi; Lecht, Shimon; Oron-Herman, Mor; Momic, Tatjana; Nissan, Aviram; Lazarovici, Philip

2013-07-12

In this study, we present the applicability of imaging epidermal growth factor (EGF) receptor levels in preclinical models of COLO205 carcinoma cells in vitro, mice with orthotopic tumors and ex vivo colorectal tumor biopsies, using EGF-labeled with IRDye800CW (EGF-NIR). The near infrared (NIR) bio-imaging of COLO205 cultures indicated specific and selective binding, reflecting EGF receptors levels. In vivo imaging of tumors in mice showed that the highest signal/background ratio between tumor and adjacent tissue was achieved 48 hours post-injection. Dissected colorectal cancer tissues from different patients demonstrated ex vivo specific imaging using the NIR bio-imaging platform of the heterogeneous distributed EGF receptors. Moreover, in the adjacent gastrointestinal tissue of the same patients, which by Western blotting was demonstrated as EGF receptor negative, no labeling with EGF-NIR probe was detected. Present results support the concept of tumor imaging by measuring EGF receptor levels using EGF-NIR probe. This platform is advantageous for EGF receptor bio-imaging of the NCI-60 recommended panel of tumor cell lines including 6-9 colorectal cell lines, since it avoids radioactive probes and is appropriate for use in the clinical setting using NIR technologies in a real-time manner.

Epidermal growth factor receptors destined for the nucleus are internalized via a clathrin-dependent pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

De Angelis Campos, Ana Carolina; Rodrigues, Michele Angela; Andrade, Carolina de

2011-08-26

Highlights: {yields} EGF and its receptor translocates to the nucleus in liver cells. {yields} Real time imaging shows that EGF moves to the nucleus. {yields} EGF moves with its receptor to the nucleus. {yields} Dynamin and clathrin are necessary for EGFR nuclear translocation. -- Abstract: The epidermal growth factor (EGF) transduces its actions via the EGF receptor (EGFR), which can traffic from the plasma membrane to either the cytoplasm or the nucleus. However, the mechanism by which EGFR reaches the nucleus is unclear. To investigate these questions, liver cells were analyzed by immunoblot of cell fractions, confocal immunofluorescence and realmore » time confocal imaging. Cell fractionation studies showed that EGFR was detectable in the nucleus after EGF stimulation with a peak in nuclear receptor after 10 min. Movement of EGFR to the nucleus was confirmed by confocal immunofluorescence and labeled EGF moved with the receptor to the nucleus. Small interference RNA (siRNA) was used to knockdown clathrin in order to assess the first endocytic steps of EGFR nuclear translocation in liver cells. A mutant dynamin (dynamin K44A) was also used to determine the pathways for this traffic. Movement of labeled EGF or EGFR to the nucleus depended upon dynamin and clathrin. This identifies the pathway that mediates the first steps for EGFR nuclear translocation in liver cells.« less

Up-regulation of proproliferative genes and the ligand/receptor pair placental growth factor and vascular endothelial growth factor receptor 1 in hepatitis C cirrhosis.

PubMed

Huang, Xiao X; McCaughan, Geoffrey W; Shackel, Nicholas A; Gorrell, Mark D

2007-09-01

Cirrhosis can lead to hepatocellular carcinoma (HCC). Non-diseased liver and hepatitis C virus (HCV)-associated cirrhosis with or without HCC were compared. Proliferation pathway genes, immune response genes and oncogenes were analysed by a quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and immunostaining. Real-time RT-PCR showed up-regulation of genes in HCV cirrhosis including the proliferation-associated genes bone morphogenetic protein 3 (BMP3), placental growth factor 3 (PGF3), vascular endothelial growth factor receptor 1 (VEGFR1) and soluble VEGFR1, the oncogene FYN, and the immune response-associated genes toll-like receptor 9 (TLR9) and natural killer cell transcript 4 (NK4). Expressions of TLR2 and the oncogenes B-cell CLL/lymphoma 9 (BCL9) and PIM2 were decreased in HCV cirrhosis. In addition, PIM2 and TLR2 were increased in HCV cirrhosis with HCC compared with HCV cirrhosis. The ligand/receptor pair PGF and VEGFR1 was intensely expressed by the portal tract vascular endothelium. VEGFR1 was expressed in reactive biliary epithelial structures in fibrotic septum and in some stellate cells and macrophages. PGF and VEGFR1 may have an important role in the pathogenesis of the neovascular response in cirrhosis.

T-cell Receptor Signaling Activates an ITK/NF-κB/GATA-3 axis in T-cell Lymphomas Facilitating Resistance to Chemotherapy.

PubMed

Wang, Tianjiao; Lu, Ye; Polk, Avery; Chowdhury, Pinki; Zamalloa, Carlos Murga; Fujiwara, Hiroshi; Suemori, Koichiro; Beyersdorf, Niklas; Hristov, Alexandra C; Lim, Megan S; Bailey, Nathanael G; Wilcox, Ryan A

2017-05-15

Purpose: T-cell lymphomas are a molecularly heterogeneous group of non-Hodgkin lymphomas (NHL) that account for a disproportionate number of NHL disease-related deaths due to their inherent and acquired resistance to standard multiagent chemotherapy regimens. Despite their molecular heterogeneity and frequent loss of various T cell-specific receptors, the T-cell antigen receptor is retained in the majority of these lymphomas. As T-cell receptor (TCR) engagement activates a number of signaling pathways and transcription factors that regulate T-cell growth and survival, we examined the TCR's role in mediating resistance to chemotherapy. Experimental Design: Genetic and pharmacologic strategies were utilized to determine the contribution of tyrosine kinases and transcription factors activated in conventional T cells following TCR engagement in acquired chemotherapy resistance in primary T-cell lymphoma cells and patient-derived cell lines. Results: Here, we report that TCR signaling activates a signaling axis that includes ITK, NF-κB, and GATA-3 and promotes chemotherapy resistance. Conclusions: These observations have significant therapeutic implications, as pharmacologic inhibition of ITK prevented the activation of this signaling axis and overcame chemotherapy resistance. Clin Cancer Res; 23(10); 2506-15. ©2016 AACR . ©2016 American Association for Cancer Research.

A Transcriptional Regulatory Network Containing Nuclear Receptors and Long Noncoding RNAs Controls Basal and Drug-Induced Expression of Cytochrome P450s in HepaRG Cells.

PubMed

Chen, Liming; Bao, Yifan; Piekos, Stephanie C; Zhu, Kexin; Zhang, Lirong; Zhong, Xiao-Bo

2018-07-01

Cytochrome P450 (P450) enzymes are responsible for metabolizing drugs. Expression of P450s can directly affect drug metabolism, resulting in various outcomes in therapeutic efficacy and adverse effects. Several nuclear receptors are transcription factors that can regulate expression of P450s at both basal and drug-induced levels. Some long noncoding RNAs (lncRNAs) near a transcription factor are found to participate in the regulatory functions of the transcription factors. The aim of this study is to determine whether there is a transcriptional regulatory network containing nuclear receptors and lncRNAs controlling both basal and drug-induced expression of P450s in HepaRG cells. Small interfering RNAs or small hairpin RNAs were applied to knock down four nuclear receptors [hepatocyte nuclear factor 1 α (HNF1 α ), hepatocyte nuclear factor 4 α (HNF4 α ), pregnane X receptor (PXR), and constitutive androstane receptor (CAR)] as well as two lncRNAs [HNF1 α antisense RNA 1 (HNF1 α -AS1) and HNF4 α antisense RNA 1 (HNF4 α -AS1)] in HepaRG cells with or without treatment of phenobarbital or rifampicin. Expression of eight P450 enzymes was examined in both basal and drug-induced levels. CAR and PXR mainly regulated expression of specific P450s. HNF1 α and HNF4 α affected expression of a wide range of P450s as well as other transcription factors. HNF1 α and HNF4 α controlled the expression of their neighborhood lncRNAs, HNF1 α -AS1 and HNF4 α -AS1, respectively. HNF1 α -AS1 and HNF4 α -AS1 was also involved in the regulation of P450s and transcription factors in diverse manners. Altogether, our study concludes that a transcription regulatory network containing the nuclear receptors and lncRNAs controls both basal and drug-induced expression of P450s in HepaRG cells. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

Augmented macrophage differentiation and polarization of tumor-associated macrophages towards M1 subtype in listeria-administered tumor-bearing host.

PubMed

Rai, Rakesh K; Vishvakarma, Naveen K; Mohapatra, Tribhuban M; Singh, Sukh Mahendra

2012-09-01

This study investigates the effect of Listeria administration on differentiation of macrophages from precursor bone marrow cells and functional status of tumor-associated macrophages (TAM). Listeria administration not only resulted in an augmented infiltration of tumor by F4/80 macrophages but also repolarized the functional status of TAM displaying features of some M1 macrophage subtype with upregulated phagocytosis and tumoricidal activity accompanied by altered expression of monocarboxylate transporter-1, toll-like receptor-2, surface markers: CD11c, interleukin-2 receptor, CD62L, and secreted molecules: nitric oxide, interleukin (IL)-1, IL-6, tumor necrosis factor-α, and vascular endothelial growth factor. Declined tumor cell survival and modulated repertoire of cytokines: interferon-γ, IL-6, IL-10, and transforming growth factor-β in tumor microenvironment indicated their role in polarization of TAM towards proinflammatory state. Bone marrow cell of Listeria-administered tumor-bearing mice showed augmented survival, declined expression of p53 upregulated modulator of apoptosis with an upregulated differentiation into activation responsive bone marrow-derived macrophages along with altered expression of macrophage-colony stimulating factor, macrophage-colony stimulating factor receptor, and granulocyte macrophage-colony stimulating factor receptor. These findings indicate that Listeria infection is associated with an augmented differentiation of macrophages accompanied by tumoricidal activation of TAM.

Involvement of the nuclear factor-κB signaling pathway in the regulation of CXC chemokine receptor-4 expression in neuroblastoma cells induced by tumor necrosis factor-α.

PubMed

Zhi, Yunlai; Lu, Hongting; Duan, Yuhe; Sun, Weisheng; Guan, Ge; Dong, Qian; Yang, Chuanmin

2015-02-01

Metastasis is a hallmark of malignant neuroblastoma and is the main reason for therapeutic failure and recurrence of the tumor. The CXC chemokine receptor-4 (CXCR4), a Gi protein-coupled receptor for the ligand CXCL12/stromal cell-derived factor-1α (SDF-1α), is expressed in various types of tumor. This receptor mediates the homing of tumor cells to specific organs that express the ligand, CXCL12, for this receptor and plays an important role in tumor growth, invasion, metastasis and angiogenesis. In the present study, the inflammatory cytokine, tumor necrosis factor‑α (TNF‑α) upregulated CXCR4 expression in neuroblastoma cells and increased migration to the CXCR4 ligand SDF‑1α. In addition, this effect was dependent upon NF-κB transcriptional activity, as blocking the NF-κB pathway with pyrrolidinedithiocarbamic acid ammonium salt suppressed TNF-α‑induced upregulation of CXCR4 expression and reduced the migration towards the CXCR4 ligand, SDF-1α. Treating neuroblastoma cells with TNF-α resulted in the activation of nuclear factor-kappa B (NF-κB) and subsequently, the translocation of NF-κB from the cytoplasm to the nucleus. Using immunohistochemistry, NF‑κB and CXCR4 were significantly correlated with each other (P=0.0052, Fisher's exact test) in a cohort of neuroblastoma samples (n=80). The present study indicates that the inflammatory cytokine, TNF-α, partially functions through the NF‑κB signaling pathway to upregulate CXCR4 expression to foster neuroblastoma cell metastasis. These findings indicate that effective inhibition of neuroblastoma metastasis should be directed against the inflammatory cytokine-induced NF‑κB/CXCR4/SDF‑1α signaling pathway.

Insulin-like growth factor-I receptor activity is essential for Kaposi's sarcoma growth and survival.

PubMed

Catrina, S-B; Lewitt, M; Massambu, C; Dricu, A; Grünler, J; Axelson, M; Biberfeld, P; Brismar, K

2005-04-25

Kaposi's sarcoma (KS) is a highly vascular tumour and is the most common neoplasm associated with human immunodeficiency virus (HIV-1) infection. Growth factors, in particular vascular endothelial growth factor (VEGF), have been shown to play an important role in its development. The role of insulin-like growth factors (IGFs) in the pathophysiology of different tumours led us to evaluate the role of IGF system in KS. The IGF-I receptors (IGF-IR) were identified by immunohistochemistry in biopsies taken from patients with different AIDS/HIV-related KS stages and on KSIMM cells (an established KS-derived cell line). Insulin-like growth factor-I is a growth factor for KSIMM cells with a maximum increase of 3H-thymidine incorporation of 130 +/- 27.6% (P < 0.05) similar to that induced by VEGF and with which it is additive (281 +/- 13%) (P < 0.05). Moreover, specific blockade of the receptor (either by alpha IR3 antibody or by picropodophyllin, a recently described selective IGF-IR tyrosine phosphorylation inhibitor) induced KSIMM apoptosis, suggesting that IGF-IR agonists (IGF-I and -II) mediate antiapoptotic signals for these cells. We were able to identify an autocrine loop essential for KSIMM cell survival in which IGF-II is the IGF-IR agonist secreted by the cells. In conclusion, IGF-I pathway inhibition is a promising therapeutical approach for KS tumours.

Antitumor activity of a novel anti-vascular endothelial growth factor receptor-1 monoclonal antibody that does not interfere with ligand binding

PubMed Central

Tentori, Lucio; Scimeca, Manuel; Dorio, Annalisa S.; Atzori, Maria Grazia; Failla, Cristina M.; Morea, Veronica; Bonanno, Elena; D'Atri, Stefania; Lacal, Pedro M.

2016-01-01

Vascular endothelial growth factor receptor-1 (VEGFR-1) is a tyrosine kinase transmembrane receptor that has also a soluble isoform containing most of the extracellular ligand binding domain (sVEGFR-1). VEGF-A binds to both VEGFR-2 and VEGFR-1, whereas placenta growth factor (PlGF) interacts exclusively with VEGFR-1. In this study we generated an anti-VEGFR-1 mAb (D16F7) by immunizing BALB/C mice with a peptide that we had previously reported to inhibit angiogenesis and endothelial cell migration induced by PlGF. D16F7 did not affect binding of VEGF-A or PlGF to VEGFR-1, thus allowing sVEGFR-1 to act as decoy receptor for these growth factors, but it hampered receptor homodimerization and activation. D16F7 inhibited both the chemotactic response of human endothelial, myelomonocytic and melanoma cells to VEGFR-1 ligands and vasculogenic mimicry by tumor cells. Moreover, D16F7 exerted in vivo antiangiogenic effects in a matrigel plug assay. Importantly, D16F7 inhibited tumor growth and was well tolerated by B6D2F1 mice injected with syngeneic B16F10 melanoma cells. The antitumor effect was associated with melanoma cell apoptosis, vascular abnormalities and decrease of both monocyte/macrophage infiltration and myeloid progenitor mobilization. For all the above, D16F7 may be exploited in the therapy of metastatic melanoma and other tumors or pathological conditions involving VEGFR-1 activation. PMID:27655684

Novel liposomal combination treatments using dual genes knockdown in oral cancer treatment

NASA Astrophysics Data System (ADS)

Wu, Jyun-Sian; Yeh, Chia-Hsien; Huang, Leaf; Hsu, Yih-Chih

2018-02-01

Small interfering RNA (siRNA) can be used to treat tumor because it can effectively knockdown target oncoprotein expression and it leads to cancer cell death and apoptosis. Hypoxia-inducible factors-1 (HIF-1) is a transcription factor gene. Its high expression of tumor hypoxia cells, activation of transcription factor HIF-1α and angiogenesis found in most cancerous tissues. HIF-1α protein in cancer cells are critical to cell survival, tumor growth and proliferation. Epidermal growth factor receptor (EGFR) gene is another common head and neck oncogene. The dual self-designed siRNA sequences were encapsulated in the lipid-calcium-phosphate (LCP) and targeted to sigma receptors on the surface of cancer cells via binding to amino ethyl anisamide (AEAA). We used human oral cancer cells to establish the xenograft animal model to study the combination therapy for therapeutic results.

Cargo binding promotes KDEL receptor clustering at the mammalian cell surface

PubMed Central

Becker, Björn; Shaebani, M. Reza; Rammo, Domenik; Bubel, Tobias; Santen, Ludger; Schmitt, Manfred J.

2016-01-01

Transmembrane receptor clustering is a ubiquitous phenomenon in pro- and eukaryotic cells to physically sense receptor/ligand interactions and subsequently translate an exogenous signal into a cellular response. Despite that receptor cluster formation has been described for a wide variety of receptors, ranging from chemotactic receptors in bacteria to growth factor and neurotransmitter receptors in mammalian cells, a mechanistic understanding of the underlying molecular processes is still puzzling. In an attempt to fill this gap we followed a combined experimental and theoretical approach by dissecting and modulating cargo binding, internalization and cellular response mediated by KDEL receptors (KDELRs) at the mammalian cell surface after interaction with a model cargo/ligand. Using a fluorescent variant of ricin toxin A chain as KDELR-ligand (eGFP-RTAH/KDEL), we demonstrate that cargo binding induces dose-dependent receptor cluster formation at and subsequent internalization from the membrane which is associated and counteracted by anterograde and microtubule-assisted receptor transport to preferred docking sites at the plasma membrane. By means of analytical arguments and extensive numerical simulations we show that cargo-synchronized receptor transport from and to the membrane is causative for KDELR/cargo cluster formation at the mammalian cell surface. PMID:27353000

Cargo binding promotes KDEL receptor clustering at the mammalian cell surface

NASA Astrophysics Data System (ADS)

Becker, Björn; Shaebani, M. Reza; Rammo, Domenik; Bubel, Tobias; Santen, Ludger; Schmitt, Manfred J.

2016-06-01

Transmembrane receptor clustering is a ubiquitous phenomenon in pro- and eukaryotic cells to physically sense receptor/ligand interactions and subsequently translate an exogenous signal into a cellular response. Despite that receptor cluster formation has been described for a wide variety of receptors, ranging from chemotactic receptors in bacteria to growth factor and neurotransmitter receptors in mammalian cells, a mechanistic understanding of the underlying molecular processes is still puzzling. In an attempt to fill this gap we followed a combined experimental and theoretical approach by dissecting and modulating cargo binding, internalization and cellular response mediated by KDEL receptors (KDELRs) at the mammalian cell surface after interaction with a model cargo/ligand. Using a fluorescent variant of ricin toxin A chain as KDELR-ligand (eGFP-RTAH/KDEL), we demonstrate that cargo binding induces dose-dependent receptor cluster formation at and subsequent internalization from the membrane which is associated and counteracted by anterograde and microtubule-assisted receptor transport to preferred docking sites at the plasma membrane. By means of analytical arguments and extensive numerical simulations we show that cargo-synchronized receptor transport from and to the membrane is causative for KDELR/cargo cluster formation at the mammalian cell surface.

A single tyrosine of the interleukin-9 (IL-9) receptor is required for STAT activation, antiapoptotic activity, and growth regulation by IL-9.

PubMed

Demoulin, J B; Uyttenhove, C; Van Roost, E; DeLestré, B; Donckers, D; Van Snick, J; Renauld, J C

1996-09-01

Interleukin-9 (IL-9), a T-cell-derived cytokine, interacts with a specific receptor associated with the IL-2 receptor gamma chain. In this report, we analyze the functional domains of the human IL-9 receptor transfected into mouse lymphoid cell lines. Three different functions were examined: growth stimulation in factor-dependent pro-B Ba/F3 cells, protection against dexamethasone-induced apoptosis, and Ly-6A2 induction in BW5147 lymphoma cells. The results indicated that a single tyrosine, at position 116 in the cytoplasmic domain, was required for all three activities. In addition, we observed that human IL-9 reduced the proliferation rate of transfected BW5147 cells, an effect also dependent on the same tyrosine. This amino acid was necessary for IL-9-mediated tyrosine phosphorylation of the receptor and for STAT activation but not for IRS-2/4PS activation or for JAK1 phosphorylation, which depended on a domain closer to the plasma membrane. We also showed that JAK1 was constitutively associated with the IL-9 receptor. Activated STAT complexes induced by IL-9 were found to contain STAT1, STAT3, and STAT5 transcription factors. Moreover, sequence homologies between human IL-9 receptor tyrosine 116 and tyrosines (of other receptors activating STAT3 and STAT5 were observed. Taken together, these data indicate that a single tyrosine of the IL-9 receptor, required for activation of three different STAT proteins, is necessary for distinct activities of this cytokine, including proliferative responses.

Expression of insulin-like growth factor-1 and insulin-like growth factor-1 receptors in EL4 lymphoma cells overexpressing growth hormone.

PubMed

Weigent, Douglas A; Arnold, Robyn E

2005-03-01

Almost all of the previous studies with growth hormone (GH) have been done with exogenously supplied GH and, therefore, involve actions of the hormone through its receptor. However, the actions of endogenous or lymphocyte GH are still unclear. In a previous study, we showed that overexpression of GH (GHo) in a lymphoid cell line resulted in protection of the cells to apoptosis mediated by nitric oxide (NO). In the present study, we show that the protection from apoptosis could be transferred to control cells with culture fluids obtained from GHo cells and blocked by antibodies to the insulin-like growth factor-1 (IGF-1) or antibodies to the IGF-1-receptor (IGF-1R). Northern and Western blot analysis detected significantly higher levels of IGF-1 in cells overexpressing GH. An increase in the expression of the IGF-1R in GHo cells was also detected by Western blot analysis, (125)I-IGF-1 binding and analysis of IGF-1R promoter luciferase constructs. Transfection of GHo cells with a dominant negative IGF-1R mutant construct blocked the generation of NO and activation of Akt seen in GHo cells compared to vector alone control EL4 cells. The results suggest that one of the consequences of the overexpression of GH, in cells lacking the GH receptor, is an increase in the expression of IGF-1 and the IGF-1R which mediate the protection of EL4 lymphoma cells from apoptosis.

Insulin-like growth factor 1 enhances the migratory capacity of mesenchymal stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yangxin; Yu, XiYong; Lin, ShuGuang

2007-05-11

Mesenchymal stem cells (MSCs) are attractive candidates for cell based therapies. However, the mechanisms responsible for stem cell migration and homing after transplantation remain unknown. It has been shown that insulin-like growth factor-1 (IGF-1) induces proliferation and migration of some cell types, but its effects on stem cells have not been investigated. We isolated and cultured MSC from rat bone marrow, and found that IGF-1 increased the expression levels of the chemokine receptor CXCR4 (receptor for stromal cell-derived factor-1, SDF-1). Moreover, IGF-1 markedly increased the migratory response of MSC to SDF-1. The IGF-1-induced increase in MSC migration in response tomore » SDF-1 was attenuated by PI3 kinase inhibitor (LY294002 and wortmannin) but not by mitogen-activated protein/ERK kinase inhibitor PD98059. Our data indicate that IGF-1 increases MSC migratory responses via CXCR4 chemokine receptor signaling which is PI3/Akt dependent. These findings provide a new paradigm for biological effects of IGF-1 on MSC and have implications for the development of novel stem cell therapeutic strategies.« less

Hyperprolactinemia following chronic alcohol administration.

PubMed

Sarkar, Dipak K

2010-01-01

There are several reports showing evidence for the existence of high levels of prolactin (PRL) in alcoholic men and women. Alcohol-induced hyperprolactinemia has also been demonstrated in nonhuman primates and laboratory animals. Therefore, the clinical data as well as animal data suggest that ethanol consumption is a positive risk factor for hyperprolactinemia. In animal studies, it was found that chronic ethanol administration not only elevates plasma levels of PRL but also increases proliferation of pituitary lactotropes. Ethanol action on lactotropes involves crosstalk with estradiol-responsive signaling cascade or estradiol-regulated cell-cell communication. Additionally, it involves suppression of dopamine D2 receptors inhibition of G proteins and intracellular cyclic adenosine monophosphate (cAMP), modulation of transforming growth factor-beta (TGF-beta) isoforms and their receptors (TbetaRII), as well as factors secondary to TGF-beta actions, including production of beta-fibroblast growth factor (bFGF) from follicular-stellate cells. The downstream signaling that governs b-FGF production and secretion involves activation of the MAP kinase p44/42-dependent pathway. A coordinated suppression of D2 receptor- and TbetaRII receptor-mediated signaling as well as enhancement of bFGF activity might be critical for ethanol action on PRL production and cell proliferation in lactotropes. Copyright (c) 2010 S. Karger AG, Basel.

Establishment of primary mixed cell cultures from spontaneous canine mammary tumors: Characterization of classic and new cancer-associated molecules

PubMed Central

Gentile, Luciana B.; Nagamine, Marcia K.; Biondi, Luiz R.; Sanches, Daniel S.; Toyota, Fábio; Giovani, Tatiane M.; de Jesus, Isis P.; da Fonseca, Ivone I. M.; Queiroz-Hazarbassanov, Nicolle; Diaz, Bruno L.; Salles Gomes, Cristina de O. Massoco

2017-01-01

There are many factors which make canine cancer like cancer in humans. The occurrence of spontaneous mammary tumors in pet dogs, tumor genetics, molecular targets and exposure to the same environmental risk factors are among these factors. Therefore, the study of canine cancer can provide useful information to the oncology field. This study aimed to establish and characterize a panel of primary mixed cell cultures obtained from spontaneous canine mammary tumors. Eight established cell cultures obtained from one normal mammary gland, one complex adenoma, one mixed adenoma, two complex carcinomas and two mixed carcinomas were analyzed. The gene expression levels of classic molecular cancer players such as fibroblast growth factor receptor (FGFR) 2, breast cancer (BRCA) 1, BRCA2 and estrogen receptor (ESR) 1 were evaluated. For the first time, three orphan nuclear receptors, estrogen-related receptors (ERRs) α, β and γ were studied in canine mammary cancer. The highest expression level of ERRα was observed in complex carcinoma-derived cell culture, while the highest levels of ERRβ and γ were observed in cells derived from a mixed carcinoma. Meanwhile, complex carcinomas presented the highest levels of expression of ESR1, BRCA1 and FGFR2 among all samples. BRCA2 was found exclusively in complex adenoma. The transcription factor GATA3 had its highest levels in mixed carcinoma samples and its lowest levels in complex adenoma. Proliferation assays were also performed to evaluate the mixed cell cultures response to ER ligands, genistein and DES, both in normoxia and hypoxic conditions. Our results demonstrate that morphological and functional studies of primary mixed cell cultures derived from spontaneous canine mammary tumors are possible and provide valuable tool for the study of various stages of mammary cancer development. PMID:28945747

Oxygen Modulates Human Decidual Natural Killer Cell Surface Receptor Expression and Interactions with Trophoblasts1

PubMed Central

Wallace, Alison E.; Goulwara, Sonu S.; Whitley, Guy S.; Cartwright, Judith E.

2014-01-01

Decidual natural killer (dNK) cells have been shown to both promote and inhibit trophoblast behavior important for decidual remodeling in pregnancy and have a distinct phenotype compared to peripheral blood NK cells. We investigated whether different levels of oxygen tension, mimicking the physiological conditions of the decidua in early pregnancy, altered cell surface receptor expression and activity of dNK cells and their interactions with trophoblast. dNK cells were isolated from terminated first-trimester pregnancies and cultured in oxygen tensions of 3%, 10%, and 21% for 24 h. Cell surface receptor expression was examined by flow cytometry, and the effects of secreted factors in conditioned medium (CM) on the trophoblast cell line SGHPL-4 were assessed in vitro. SGHPL-4 cells treated with dNK cell CM incubated in oxygen tensions of 10% were significantly more invasive (P < 0.05) and formed endothelial-like networks to a greater extent (P < 0.05) than SGHPL-4 cells treated with dNK cell CM incubated in oxygen tensions of 3% or 21%. After 24 h, a lower percentage of dNK cells expressed CD56 at 21% oxygen (P < 0.05), and an increased percentage of dNK cells expressed NKG2D at 10% oxygen (P < 0.05) compared to other oxygen tensions, with large patient variation. This study demonstrates dNK cell phenotype and secreted factors are modulated by oxygen tension, which induces changes in trophoblast invasion and endovascular-like differentiation. Alterations in dNK cell surface receptor expression and secreted factors at different oxygen tensions may represent regulation of function within the decidua during the first trimester of pregnancy. PMID:25232021

Poly(ADP-ribose) Polymerase Inhibitors Sensitize Cancer Cells to Death Receptor-mediated Apoptosis by Enhancing Death Receptor Expression*

PubMed Central

Meng, X. Wei; Koh, Brian D.; Zhang, Jin-San; Flatten, Karen S.; Schneider, Paula A.; Billadeau, Daniel D.; Hess, Allan D.; Smith, B. Douglas; Karp, Judith E.; Kaufmann, Scott H.

2014-01-01

Recombinant human tumor necrosis factor-α-related apoptosis inducing ligand (TRAIL), agonistic monoclonal antibodies to TRAIL receptors, and small molecule TRAIL receptor agonists are in various stages of preclinical and early phase clinical testing as potential anticancer drugs. Accordingly, there is substantial interest in understanding factors that affect sensitivity to these agents. In the present study we observed that the poly(ADP-ribose) polymerase (PARP) inhibitors olaparib and veliparib sensitize the myeloid leukemia cell lines ML-1 and K562, the ovarian cancer line PEO1, non-small cell lung cancer line A549, and a majority of clinical AML isolates, but not normal marrow, to TRAIL. Further analysis demonstrated that PARP inhibitor treatment results in activation of the FAS and TNFRSF10B (death receptor 5 (DR5)) promoters, increased Fas and DR5 mRNA, and elevated cell surface expression of these receptors in sensitized cells. Chromatin immunoprecipitation demonstrated enhanced binding of the transcription factor Sp1 to the TNFRSF10B promoter in the presence of PARP inhibitor. Knockdown of PARP1 or PARP2 (but not PARP3 and PARP4) not only increased expression of Fas and DR5 at the mRNA and protein level, but also recapitulated the sensitizing effects of the PARP inhibition. Conversely, Sp1 knockdown diminished the PARP inhibitor effects. In view of the fact that TRAIL is part of the armamentarium of natural killer cells, these observations identify a new facet of PARP inhibitor action while simultaneously providing the mechanistic underpinnings of a novel therapeutic combination that warrants further investigation. PMID:24895135

The mannose 6-phosphate-binding sites of M6P/IGF2R determine its capacity to suppress matrix invasion by squamous cell carcinoma cells

PubMed Central

Probst, Olivia C.; Karayel, Evren; Schida, Nicole; Nimmerfall, Elisabeth; Hehenberger, Elisabeth; Puxbaum, Verena; Mach, Lukas

2013-01-01

The M6P (mannose 6-phosphate)/IGF2R (insulin-like growth factor II receptor) interacts with a variety of factors that impinge on tumour invasion and metastasis. It has been shown that expression of wild-type M6P/IGF2R reduces the tumorigenic and invasive properties of receptor-deficient SCC-VII squamous cell carcinoma cells. We have now used mutant forms of M6P/IGF2R to assess the relevance of the different ligand-binding sites of the receptor for its biological activities in this cellular system. The results of the present study demonstrate that M6P/IGF2R does not require a functional binding site for insulin-like growth factor II for inhibition of anchorage-independent growth and matrix invasion by SCC-VII cells. In contrast, the simultaneous mutation of both M6P-binding sites is sufficient to impair all cellular functions of the receptor tested. These findings highlight that the interaction between M6P/IGF2R and M6P-modified ligands is not only important for intracellular accumulation of lysosomal enzymes and formation of dense lysosomes, but is also crucial for the ability of the receptor to suppress SCC-VII growth and invasion. The present study also shows that some of the biological activities of M6P/IGF2R in SCC-VII cells strongly depend on a functional M6P-binding site within domain 3, thus providing further evidence for the non-redundant cellular functions of the individual carbohydrate-binding domains of the receptor. PMID:23347038

DNA binding triggers tetramerization of the glucocorticoid receptor in live cells

PubMed Central

Presman, Diego M.; Ganguly, Sourav; Schiltz, R. Louis; Johnson, Thomas A.; Karpova, Tatiana S.; Hager, Gordon L.

2016-01-01

Transcription factors dynamically bind to chromatin and are essential for the regulation of genes. Although a large percentage of these proteins appear to self-associate to form dimers or higher order oligomers, the stoichiometry of DNA-bound transcription factors has been poorly characterized in vivo. The glucocorticoid receptor (GR) is a ligand-regulated transcription factor widely believed to act as a dimer or a monomer. Using a unique set of imaging techniques coupled with a cell line containing an array of DNA binding elements, we show that GR is predominantly a tetramer when bound to its target DNA. We find that DNA binding triggers an interdomain allosteric regulation within the GR, leading to tetramerization. We therefore propose that dynamic changes in GR stoichiometry represent a previously unidentified level of regulation in steroid receptor activation. Quaternary structure analysis of other members of the steroid receptor family (estrogen, androgen, and progesterone receptors) reveals variation in oligomerization states among this family of transcription factors. Because GR’s oligomerization state has been implicated in therapy outcome, our findings open new doors to the rational design of novel GR ligands and redefine the quaternary structure of steroid receptors. PMID:27382178

Cytoskeleton in Mast Cell Signaling

PubMed Central

Dráber, Pavel; Sulimenko, Vadym; Dráberová, Eduarda

2012-01-01

Mast cell activation mediated by the high affinity receptor for IgE (FcεRI) is a key event in allergic response and inflammation. Other receptors on mast cells, as c-Kit for stem cell factor and G protein-coupled receptors (GPCRs) synergistically enhance the FcεRI-mediated release of inflammatory mediators. Activation of various signaling pathways in mast cells results in changes in cell morphology, adhesion to substrate, exocytosis, and migration. Reorganization of cytoskeleton is pivotal in all these processes. Cytoskeletal proteins also play an important role in initial stages of FcεRI and other surface receptors induced triggering. Highly dynamic microtubules formed by αβ-tubulin dimers as well as microfilaments build up from polymerized actin are affected in activated cells by kinases/phosphatases, Rho GTPases and changes in concentration of cytosolic Ca2+. Also important are nucleation proteins; the γ-tubulin complexes in case of microtubules or Arp 2/3 complex with its nucleation promoting factors and formins in case of microfilaments. The dynamic nature of microtubules and microfilaments in activated cells depends on many associated/regulatory proteins. Changes in rigidity of activated mast cells reflect changes in intermediate filaments build up from vimentin. This review offers a critical appraisal of current knowledge on the role of cytoskeleton in mast cells signaling. PMID:22654883

Perspectives on the Trypanosoma cruzi–host cell receptor interactions

PubMed Central

Villalta, Fernando; Scharfstein, Julio; Ashton, Anthony W.; Tyler, Kevin M.; Guan, Fangxia; Mukherjee, Shankar; Lima, Maria F.; Alvarez, Sandra; Weiss, Louis M.; Huang, Huan; Machado, Fabiana S.

2009-01-01

Chagas disease is caused by the parasite Trypanosoma cruzi. The critical initial event is the interaction of the trypomastigote form of the parasite with host receptors. This review highlights recent observations concerning these interactions. Some of the key receptors considered are those for thromboxane, bradykinin, and for the nerve growth factor TrKA. Other important receptors such as galectin-3, thrombospondin, and laminin are also discussed. Investigation into the molecular biology and cell biology of host receptors for T. cruzi may provide novel therapeutic targets. PMID:19283409

Opiate antagonist prevents μ- and δ-opiate receptor dimerization to facilitate ability of agonist to control ethanol-altered natural killer cell functions and mammary tumor growth.

PubMed

Sarkar, Dipak K; Sengupta, Amitabha; Zhang, Changqing; Boyadjieva, Nadka; Murugan, Sengottuvelan

2012-05-11

In the natural killer (NK) cells, δ-opiate receptor (DOR) and μ-opioid receptor (MOR) interact in a feedback manner to regulate cytolytic function with an unknown mechanism. Using RNK16 cells, a rat NK cell line, we show that MOR and DOR monomer and dimer proteins existed in these cells and that chronic treatment with a receptor antagonist reduced protein levels of the targeted receptor but increased levels of opposing receptor monomer and homodimer. The opposing receptor-enhancing effects of MOR and DOR antagonists were abolished following receptor gene knockdown by siRNA. Ethanol treatment increased MOR and DOR heterodimers while it decreased the cellular levels of MOR and DOR monomers and homodimers. The opioid receptor homodimerization was associated with an increased receptor binding, and heterodimerization was associated with a decreased receptor binding and the production of cytotoxic factors. Similarly, in vivo, opioid receptor dimerization, ligand binding of receptors, and cell function in immune cells were promoted by chronic treatment with an opiate antagonist but suppressed by chronic ethanol feeding. Additionally, a combined treatment of an MOR antagonist and a DOR agonist was able to reverse the immune suppressive effect of ethanol and reduce the growth and progression of mammary tumors in rats. These data identify a role of receptor dimerization in the mechanism of DOR and MOR feedback interaction in NK cells, and they further elucidate the potential for the use of a combined opioid antagonist and agonist therapy for the treatment of immune incompetence and cancer and alcohol-related diseases.

Epidermal growth factor receptor (EGFR) transactivation by estrogen via the G-protein-coupled receptor, GPR30: a novel signaling pathway with potential significance for breast cancer.

PubMed

Filardo, Edward J

2002-02-01

The biological and biochemical effects of estrogen have been ascribed to its known receptors, which function as ligand-inducible transcription factors. However, estrogen also triggers rapid activation of classical second messengers (cAMP, calcium, and inositol triphosphate) and stimulation of intracellular signaling cascades mitogen-activated protein kinase (MAP K), PI3K and eNOS. These latter events are commonly activated by membrane receptors that either possess intrinsic tyrosine kinase activity or couple to heterotrimeric G-proteins. We have shown that estrogen transactivates the epidermal growth factor receptor (EGFR) to MAP K signaling axis via the G-protein-coupled receptor (GPCR), GPR30, through the release of surface-bound proHB-EGF from estrogen receptor (ER)-negative human breast cancer cells [Molecular Endocrinology 14 (2000) 1649]. This finding is consistent with a growing body of evidence suggesting that transactivation of EGFRs by GPCRs is a recurrent theme in cell signaling. GPCR-mediated transactivation of EGFRs by estrogen provides a previously unappreciated mechanism of cross-talk between estrogen and serum growth factors, and explains prior data reporting the EGF-like effects of estrogen. This novel mechanism by which estrogen activates growth factor-dependent signaling and its implications for breast cancer biology are discussed further in this review.

Effect of The Receptor Activator of Nuclear Factor кB and RANK Ligand on In Vitro Differentiation of Cord Blood CD133(+) Hematopoietic Stem Cells to Osteoclasts.

PubMed

Kalantari, Nasim; Abroun, Saeid; Soleimani, Masoud; Kaviani, Saeid; Azad, Mehdi; Eskandari, Fatemeh; Habibi, Hossein

2016-01-01

Receptor activator of nuclear factor-kappa B ligand (RANKL) appears to be an osteoclast-activating factor, bearing an important role in the pathogenesis of multiple myeloma. Some studies demonstrated that U-266 myeloma cell line and primary myeloma cells expressed RANK and RANKL. It had been reported that the expression of myeloid and monocytoid markers was increased by co-culturing myeloma cells with hematopoietic stem cells (HSCs). This study also attempted to show the molecular mechanism of RANK and RANKL on differentiation capability of human cord blood HSC to osteoclast, as well as expression of calcitonin receptor (CTR) on cord blood HSC surface. In this experimental study, CD133(+) hematopoietic stem cells were isolated from umbilical cord blood and cultured in the presence of macrophage colony-stimulating factor (M-CSF) and RANKL. Osteoclast differentiation was characterized by using tartrate-resistant acid phosphatase (TRAP) staining, giemsa staining, immunophenotyping, and reverse transcription-polymerase chain reaction (RT-PCR) assay for specific genes. Hematopoietic stem cells expressed RANK before and after differentiation into osteoclast. Compared to control group, flow cytometric results showed an increased expression of RANK after differentiation. Expression of CTR mRNA showed TRAP reaction was positive in some differentiated cells, including osteoclast cells. Presence of RANKL and M-CSF in bone marrow could induce HSCs differentiation into osteoclast.

Antitumor activity of cytotoxic T lymphocytes engineered to target vascular endothelial growth factor receptors

NASA Astrophysics Data System (ADS)

Niederman, Thomas M. J.; Ghogawala, Zoher; Carter, Bob S.; Tompkins, Hillary S.; Russell, Margaret M.; Mulligan, Richard C.

2002-05-01

The demonstration that angiogenesis is required for the growth of solid tumors has fueled an intense interest in the development of new therapeutic strategies that target the tumor vasculature. Here we report the development of an immune-based antiangiogenic strategy that is based on the generation of T lymphocytes that possess a killing specificity for cells expressing vascular endothelial growth factor receptors (VEGFRs). To target VEGFR-expressing cells, recombinant retroviral vectors were generated that encoded a chimeric T cell receptor comprised of VEGF sequences linked to intracellular signaling sequences derived from the chain of the T cell receptor. After transduction of primary murine CD8 lymphocytes by such vectors, the transduced cells were shown to possess an efficient killing specificity for cells expressing the VEGF receptor, Flk-1, as measured by in vitro cytotoxicity assays. After adoptive transfer into tumor-bearing mice, the genetically modified cytotoxic T lymphocytes strongly inhibited the growth of a variety of syngeneic murine tumors and human tumor xenografts. An increased effect on in vivo tumor growth inhibition was seen when this therapy was combined with the systemic administration of TNP-470, a conventional angiogenesis inhibitor. The utilization of the immune system to target angiogenic markers expressed on tumor vasculature may prove to be a powerful means for controlling tumor growth.

Structural Basis for Activation of the Receptor Tyrosine Kinase KIT by Stem Cell Factor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuzawa,S.; Opatowsky, Y.; Zhang, Z.

2007-01-01

Stem Cell Factor (SCF) initiates its multiple cellular responses by binding to the ectodomain of KIT, resulting in tyrosine kinase activation. We describe the crystal structure of the entire ectodomain of KIT before and after SCF stimulation. The structures show that KIT dimerization is driven by SCF binding whose sole role is to bring two KIT molecules together. Receptor dimerization is followed by conformational changes that enable lateral interactions between membrane proximal Ig-like domains D4 and D5 of two KIT molecules. Experiments with cultured cells show that KIT activation is compromised by point mutations in amino acids critical for D4-D4more » interaction. Moreover, a variety of oncogenic mutations are mapped to the D5-D5 interface. Since key hallmarks of KIT structures, ligand-induced receptor dimerization, and the critical residues in the D4-D4 interface, are conserved in other receptors, the mechanism of KIT stimulation unveiled in this report may apply for other receptor activation.« less

Virus Infection and Death Receptor-Mediated Apoptosis.

PubMed

Zhou, Xingchen; Jiang, Wenbo; Liu, Zhongshun; Liu, Shuai; Liang, Xiaozhen

2017-10-27

Virus infection can trigger extrinsic apoptosis. Cell-surface death receptors of the tumor necrosis factor family mediate this process. They either assist persistent viral infection or elicit the elimination of infected cells by the host. Death receptor-mediated apoptosis plays an important role in viral pathogenesis and the host antiviral response. Many viruses have acquired the capability to subvert death receptor-mediated apoptosis and evade the host immune response, mainly by virally encoded gene products that suppress death receptor-mediated apoptosis. In this review, we summarize the current information on virus infection and death receptor-mediated apoptosis, particularly focusing on the viral proteins that modulate death receptor-mediated apoptosis.

Virus Infection and Death Receptor-Mediated Apoptosis

PubMed Central

Zhou, Xingchen; Jiang, Wenbo; Liu, Zhongshun; Liu, Shuai; Liang, Xiaozhen

2017-01-01

Virus infection can trigger extrinsic apoptosis. Cell-surface death receptors of the tumor necrosis factor family mediate this process. They either assist persistent viral infection or elicit the elimination of infected cells by the host. Death receptor-mediated apoptosis plays an important role in viral pathogenesis and the host antiviral response. Many viruses have acquired the capability to subvert death receptor-mediated apoptosis and evade the host immune response, mainly by virally encoded gene products that suppress death receptor-mediated apoptosis. In this review, we summarize the current information on virus infection and death receptor-mediated apoptosis, particularly focusing on the viral proteins that modulate death receptor-mediated apoptosis. PMID:29077026

Secretion imbalance between tumour necrosis factor and its inhibitor in inflammatory bowel disease

PubMed Central

Noguchi, M; Hiwatashi, N; Liu, Z; Toyota, T

1998-01-01

Background—Tumour necrosis factor (TNF) α and TNF-β are soluble ligands binding to TNF receptors with similar activities; soluble TNF receptors neutralise TNF activity by acting as inhibitors. Little is known about the cytokine/soluble receptor role in inflammatory bowel disease (IBD). 
Aims—To test the hypothesis that an imbalance in secretion between TNF and TNF inhibitors plays a role in gut inflammation in patients with IBD. 
Methods—The secretion of TNF-α, TNF-β, and soluble TNF receptors was compared in the culture supernatants of colonic biopsy specimens and isolated lamina propria mononuclear cells from patients with active colonic IBD. 
Results—Spontaneous secretion of TNF-α in involved IBD mucosa was higher than in normal control and self limited colitis mucosa. Secretion of TNF-β was higher in patients with Crohn's disease than in those with ulcerative colitis. Soluble TNF receptor in IBD mucosa inhibited TNF activity. Type 2 soluble receptor release from IBD mucosa was increased in active inflammation; release from lamina propria cells was not increased. Mucosal TNF-α production correlated with severity of disease. 
Conclusions—Results showed enhanced secretion of TNF-α but failure to release enhanced amounts of soluble TNF receptor in lamina propria mononuclear cells of patients with IBD. An imbalance in secretion between TNF and TNF inhibitor may be implicated in the pathogenesis of IBD. 

 Keywords: Crohn's disease; inflammation; mucosal immunology; soluble TNF receptor; tumour necrosis factor; ulcerative colitis PMID:10189845

Single-domain antibodies that compete with the natural ligand fibroblast growth factor block the internalization of the fibroblast growth factor receptor 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Veggiani, Gianluca; Ossolengo, Giuseppe; Aliprandi, Marisa

2011-05-20

Highlights: {yields} Recombinant antibodies for FGFR1 were isolated from a llama naive library in VHH format. {yields} These antibodies compete with the natural ligand FGF-2 for the same epitope on FGFR1. {yields} The antibody competition inhibits the FGF-2-dependent internalization of FGFR1. -- Abstract: Single-domain antibodies in VHH format specific for fibroblast growth factor receptor 1 (FGFR1) were isolated from a phage-display llama naive library. In particular, phage elution in the presence of the natural receptor ligand fibroblast growth factor (FGF) allowed for the identification of recombinant antibodies that compete with FGF for the same region on the receptor surface. Thesemore » antibodies posses a relatively low affinity for FGFR1 and were never identified when unspecific elution conditions favoring highly affine binders were applied to panning procedures. Two populations of competitive antibodies were identified that labeled specifically the receptor-expressing cells in immunofluorescence and recognize distinct epitopes. Antibodies from both populations effectively prevented FGF-dependent internalization and nuclear accumulation of the receptor in cultured cells. This achievement indicates that these antibodies have a capacity to modulate the receptor physiology and, therefore, constitute powerful reagents for basic research and a potential lead for therapeutic applications.« less

Role of tissue factor and protease-activated receptors in a mouse model of endotoxemia.

PubMed

Pawlinski, Rafal; Pedersen, Brian; Schabbauer, Gernot; Tencati, Michael; Holscher, Todd; Boisvert, William; Andrade-Gordon, Patricia; Frank, Rolf Dario; Mackman, Nigel

2004-02-15

Sepsis is associated with a systemic activation of coagulation and an excessive inflammatory response. Anticoagulants have been shown to inhibit both coagulation and inflammation in sepsis. In this study, we used both genetic and pharmacologic approaches to analyze the role of tissue factor and protease-activated receptors in coagulation and inflammation in a mouse endotoxemia model. We used mice expressing low levels of the procoagulant molecule, tissue factor (TF), to analyze the effects of TF deficiency either in all tissues or selectively in hematopoietic cells. Low TF mice had reduced coagulation, inflammation, and mortality compared with control mice. Similarly, a deficiency of TF expression by hematopoietic cells reduced lipopolysaccharide (LPS)-induced coagulation, inflammation, and mortality. Inhibition of the down-stream coagulation protease, thrombin, reduced fibrin deposition and prolonged survival without affecting inflammation. Deficiency of either protease activated receptor-1 (PAR-1) or protease activated receptor-2 (PAR-2) alone did not affect inflammation or survival. However, a combination of thrombin inhibition and PAR-2 deficiency reduced inflammation and mortality. These data demonstrate that hematopoietic cells are the major pathologic site of TF expression during endotoxemia and suggest that multiple protease-activated receptors mediate crosstalk between coagulation and inflammation.

HER-3 peptide vaccines/mimics: Combined therapy with IGF-1R, HER-2, and HER-1 peptides induces synergistic antitumor effects against breast and pancreatic cancer cells.

PubMed

Miller, Megan Jo; Foy, Kevin C; Overholser, Jay P; Nahta, Rita; Kaumaya, Pravin Tp

2014-11-01

The human epidermal growth factor receptor 3 (HER-3/ErbB3) is a unique member of the human epidermal growth factor family of receptors, because it lacks intrinsic kinase activity and ability to heterodimerize with other members. HER-3 is frequently upregulated in cancers with epidermal growth factor receptor (EGFR/HER-1/ErbB1) or human epidermal growth factor receptor 2 (HER-2/ErBB2) overexpression, and targeting HER-3 may provide a route for overcoming resistance to agents that target EGFR or HER-2. We have previously developed vaccines and peptide mimics for HER-1, HER-2 and vascular endothelial growth factor (VEGF). In this study, we extend our studies by identifying and evaluating novel HER-3 peptide epitopes encompassing residues 99-122, 140-162, 237-269 and 461-479 of the HER-3 extracellular domain as putative B-cell epitopes for active immunotherapy against HER-3 positive cancers. We show that the HER-3 vaccine antibodies and HER-3 peptide mimics induced antitumor responses: inhibition of cancer cell proliferation, inhibition of receptor phosphorylation, induction of apoptosis and antibody dependent cellular cytotoxicity (ADCC). Two of the HER-3 epitopes 237-269 (domain II) and 461-479 (domain III) significantly inhibited growth of xenografts originating from both pancreatic (BxPC3) and breast (JIMT-1) cancers. Combined therapy of HER-3 (461-471) epitope with HER-2 (266-296), HER-2 (597-626), HER-1 (418-435) and insulin-like growth factor receptor type I (IGF-1R) (56-81) vaccine antibodies and peptide mimics show enhanced antitumor effects in breast and pancreatic cancer cells. This study establishes the hypothesis that combination immunotherapy targeting different signal transduction pathways can provide effective antitumor immunity and long-term control of HER-1 and HER-2 overexpressing cancers.

Effects of inhibitors of vascular endothelial growth factor receptor 2 and downstream pathways of receptor tyrosine kinases involving phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin or mitogen-activated protein kinase in canine hemangiosarcoma cell lines.

PubMed

Adachi, Mami; Hoshino, Yuki; Izumi, Yusuke; Sakai, Hiroki; Takagi, Satoshi

2016-07-01

Canine hemangiosarcoma (HSA) is a progressive malignant neoplasm with no current effective treatment. Previous studies showed that receptor tyrosine kinases and molecules within their downstream pathways involving phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (m-TOR) or mitogen-activated protein kinase (MAPK) were overexpressed in canine, human, and murine tumors, including HSA. The present study investigated the effects of inhibitors of these pathways in canine splenic and hepatic HSA cell lines using assays of cell viability and apoptosis. Inhibitors of the MAPK pathway did not affect canine HSA cell viability. However, cell viability was significantly reduced by exposure to inhibitors of vascular endothelial growth factor receptor 2 and the PI3K/Akt/m-TOR pathway; these inhibitors also induced apoptosis in these cell lines. These results suggest that these inhibitors reduce the proliferation of canine HSA cells by inducing apoptosis. Further study of these inhibitors, using xenograft mouse models of canine HSA, are warranted to explore their potential for clinical application.

Effects of inhibitors of vascular endothelial growth factor receptor 2 and downstream pathways of receptor tyrosine kinases involving phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin or mitogen-activated protein kinase in canine hemangiosarcoma cell lines

PubMed Central

Adachi, Mami; Hoshino, Yuki; Izumi, Yusuke; Sakai, Hiroki; Takagi, Satoshi

2016-01-01

Canine hemangiosarcoma (HSA) is a progressive malignant neoplasm with no current effective treatment. Previous studies showed that receptor tyrosine kinases and molecules within their downstream pathways involving phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (m-TOR) or mitogen-activated protein kinase (MAPK) were overexpressed in canine, human, and murine tumors, including HSA. The present study investigated the effects of inhibitors of these pathways in canine splenic and hepatic HSA cell lines using assays of cell viability and apoptosis. Inhibitors of the MAPK pathway did not affect canine HSA cell viability. However, cell viability was significantly reduced by exposure to inhibitors of vascular endothelial growth factor receptor 2 and the PI3K/Akt/m-TOR pathway; these inhibitors also induced apoptosis in these cell lines. These results suggest that these inhibitors reduce the proliferation of canine HSA cells by inducing apoptosis. Further study of these inhibitors, using xenograft mouse models of canine HSA, are warranted to explore their potential for clinical application. PMID:27408334

Synergic effects of mycoplasmal lipopeptides and extracellular ATP on activation of macrophages.

PubMed

Into, Takeshi; Fujita, Mari; Okusawa, Tsugumi; Hasebe, Akira; Morita, Manabu; Shibata, Ken-Ichiro

2002-07-01

Mycoplasmal lipopeptides S-(2,3-bispalmitoyloxypropyl)-CGDPKHSPKSF and S-(2,3-bispalmitoyloxypropyl)-CGNNDESNISFKEK activated a monocytic cell line, THP-1 cells, to produce tumor necrosis factor alpha. The activity of the lipopeptides was augmented by ATP in a dose-dependent manner. In addition, the level of expression of mRNAs for tumor necrosis factor alpha and interleukin-1 beta, -6, and -8 was also upregulated by the lipopeptides and/or extracellular ATP, but that of interleukin-10 was not. The P2X purinergic receptor antagonists pyridoxal phosphate 6-azophenyl 2',4'-disulfonic acid and periodate-oxidized ATP suppressed the activity of ATP to augment the activation of THP-1 cells by the lipopeptides, suggesting that P2X receptors play important roles in the activity of ATP. The nuclear factor kappa B inhibitor dexamethasone also suppressed the activity, suggesting that the activity of ATP is dependent upon the nuclear factor kappa B. Thus, these results suggest that the interaction of extracellular ATP with the P2X receptors is attributed to the activity of ATP to augment the activation of THP-1 cells by mycoplasmal lipopeptides.

Enforced expression of KDR receptor promotes proliferation, survival and megakaryocytic differentiation of TF1 progenitor cell line.

PubMed

Coppola, S; Narciso, L; Feccia, T; Bonci, D; Calabrò, L; Morsilli, O; Gabbianelli, M; De Maria, R; Testa, U; Peschle, C

2006-01-01

Vascular endothelial growth factor (VEGF) receptor-2/kinase insert domain-containing receptor (KDR) is expressed in primitive hematopoietic cells, in megakaryocytes and platelets. In primitive hematopoiesis KDR mediates cell survival via autocrine VEGF, while its effect on cell growth and differentiation has not been elucidated. We induced enforced KDR expression in the granulocyte macrophage-colony-stimulating factor (GM-CSF)-dependent TF1 progenitor cell line (TF1-KDR), treated the cells with VEGF and analyzed their response. In GM-CSF-deprived cells, VEGF induces cell proliferation and protection against apoptosis, followed by enhanced expression of megakaryocytic (MK) markers. Combined with GM-CSF, VEGF induces a mild proliferative stimulus, followed by cell adherence, accumulation in G0/G1, massive MK differentiation and Fas-mediated apoptosis. Accordingly, we observed that MK-differentiating cells, derived from hematopoietic progenitors, produce VEGF, express KDR, inhibition of which reduces MK differentiation, indicating a key role of KDR in megakaryopoiesis. In conclusion, TF1-KDR cells provide a reliable model to investigate the biochemical and molecular mechanisms underlying hematopoietic progenitor proliferation, survival and MK differentiation.

Studying the Stoichiometry of Epidermal Growth Factor Receptor in Intact Cells using Correlative Microscopy.

PubMed

Peckys, Diana B; de Jonge, Niels

2015-09-11

This protocol describes the labeling of epidermal growth factor receptor (EGFR) on COS7 fibroblast cells, and subsequent correlative fluorescence microscopy and environmental scanning electron microscopy (ESEM) of whole cells in hydrated state. Fluorescent quantum dots (QDs) were coupled to EGFR via a two-step labeling protocol, providing an efficient and specific protein labeling, while avoiding label-induced clustering of the receptor. Fluorescence microscopy provided overview images of the cellular locations of the EGFR. The scanning transmission electron microscopy (STEM) detector was used to detect the QD labels with nanoscale resolution. The resulting correlative images provide data of the cellular EGFR distribution, and the stoichiometry at the single molecular level in the natural context of the hydrated intact cell. ESEM-STEM images revealed the receptor to be present as monomer, as homodimer, and in small clusters. Labeling with two different QDs, i.e., one emitting at 655 nm and at 800 revealed similar characteristic results.

Quantification of growth factor signaling and pathway cross talk by live-cell imaging.

PubMed

Gross, Sean M; Rotwein, Peter

2017-03-01

Peptide growth factors stimulate cellular responses through activation of their transmembrane receptors. Multiple intracellular signaling cascades are engaged following growth factor-receptor binding, leading to short- and long-term biological effects. Each receptor-activated signaling pathway does not act in isolation but rather interacts at different levels with other pathways to shape signaling networks that are distinctive for each growth factor. To gain insights into the specifics of growth factor-regulated interactions among different signaling cascades, we developed a HeLa cell line stably expressing fluorescent live-cell imaging reporters that are readouts for two major growth factor-stimulated pathways, Ras-Raf-Mek-ERK and phosphatidylinositol (PI) 3-kinase-Akt. Incubation of cells with epidermal growth factor (EGF) resulted in rapid, robust, and sustained ERK signaling but shorter-term activation of Akt. In contrast, hepatocyte growth factor induced sustained Akt signaling but weak and short-lived ERK activity, and insulin-like growth factor-I stimulated strong long-term Akt responses but negligible ERK signaling. To address potential interactions between signaling pathways, we employed specific small-molecule inhibitors. In cells incubated with EGF or platelet-derived growth factor-AA, Raf activation and the subsequent stimulation of ERK reduced Akt signaling, whereas Mek inhibition, which blocked ERK activation, enhanced Akt and turned transient effects into sustained responses. Our results reveal that individual growth factors initiate signaling cascades that vary markedly in strength and duration and demonstrate in living cells the dramatic effects of cross talk from Raf and Mek to PI 3-kinase and Akt. Our data further indicate how specific growth factors can encode distinct cellular behaviors by promoting complex interactions among signaling pathways. Copyright © 2017 the American Physiological Society.

The CXCR4/SDF-1 chemokine receptor axis: a new target therapeutic for non-small cell lung cancer.

PubMed

Otsuka, Shannon; Bebb, Gwyn

2008-12-01

Chemokines are proinflammatory chemoattractant cytokines that regulate cell trafficking and adhesion. The CXCR4 chemokine receptor and its ligand, stromal cell derived factor (SDF-1), constitute a chemokine/receptor axis that has attracted great interest because of an increasing understanding of its role in cancer, including lung cancer. The CXCR4/SDF-1 complex activates several pathways that mediate chemotaxis, migration and secretion of angiopoietic factors. Neutralization of SDF-1 by anti-SDF-1 or anti-CXCR4 monoclonal antibody in preclinical in vivo studies results in a significant decrease of non-small cell lung cancer metastases. Since anti-SDF-1/CXCR4 strategies have already been developed for use in combating human immunodeficiency virus infections, it is likely that these approaches will be used in clinical trials in non-small cell lung cancer in the very near future.

Redox-dependent regulation of epidermal growth factor receptor signaling.

PubMed

Heppner, David E; van der Vliet, Albert

2016-08-01

Tyrosine phosphorylation-dependent cell signaling represents a unique feature of multicellular organisms, and is important in regulation of cell differentiation and specialized cell functions. Multicellular organisms also contain a diverse family of NADPH oxidases (NOXs) that have been closely linked with tyrosine kinase-based cell signaling and regulate tyrosine phosphorylation via reversible oxidation of cysteine residues that are highly conserved within many proteins involved in this signaling pathway. An example of redox-regulated tyrosine kinase signaling involves the epidermal growth factor receptor (EGFR), a widely studied receptor system with diverse functions in normal cell biology as well as pathologies associated with oxidative stress such as cancer. The purpose of this Graphical Redox Review is to highlight recently emerged concepts with respect to NOX-dependent regulation of this important signaling pathway. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Human Neural Cell-Based Biosensor

DTIC Science & Technology

2010-04-26

SNAP25 (SNAP25), GluR1 (GRIA1) glutamate receptor , ionotropic , AMPA1, Nav1.2 (SCN2A), Nav1.6 (SCN8A), CaV 2.1 (CACNA1A), HERG (KCNH2), and KCC2...transitions to mesenchymal progenitor cells." Tissue Eng Part A 15(8): 1897-907. Haltiwanger, R. S. and P. Stanley (2002). "Modulation of receptor ...cytometry studies previously conducted by the Stice lab identified ciliary neurotrophic factor receptor alpha (CNTFRα) as a novel cell surface marker to

P2X1 receptor-mediated inhibition of the proliferation of human coronary smooth muscle cells involving the transcription factor NR4A1.

PubMed

Hinze, Annette Viktoria; Mayer, Peter; Harst, Anja; von Kügelgen, Ivar

2013-12-01

Adenine nucleotides acting at P2X1 receptors are potent vasoconstrictors. Recently, we demonstrated that activation of adenosine A2B receptors on human coronary smooth muscle cells inhibits cell proliferation by the induction of the nuclear receptor subfamily 4, group A, member 1 (NR4A1; alternative notation Nur77). In the present study, we searched for long-term effects mediated by P2X1 receptors by analyzing receptor-mediated changes in cell proliferation and in the expression of NR4A1. Cultured human coronary smooth muscle cells were treated with selective receptor ligands. Effects on proliferation were determined by counting cells and measuring changes in impedance. The induction of transcription factors was assessed by qPCR. The P2X receptor agonist α,β-methylene-ATP and its analog β,γ-methylene-ATP inhibited cell proliferation by about 50 % after 5 days in culture with half-maximal concentrations of 0.3 and 0.08 μM, respectively. The effects were abolished or markedly attenuated by the P2X1 receptor antagonist NF449 (carbonylbis-imino-benzene-triylbis-(carbonylimino)tetrakis-benzene-1,3-disulfonic acid; 100 nM and 1 μM). α,β-methylene-ATP and β,γ-methylene-ATP applied for 30 min to 4 h increased the expression of NR4A1; NF449 blocked or attenuated this effect. Small interfering RNA directed against NR4A1 diminished the antiproliferative effects of α,β-methylene-ATP and β,γ-methylene-ATP. α,β-methylene-ATP (0.1 to 30 μM) decreased migration of cultured human coronary smooth muscle cells in a chamber measuring changes in impedance; NF449 blocked the effect. In conclusion, our results demonstrate for the first time that adenine nucleotides acting at P2X1 receptors inhibit the proliferation of human coronary smooth muscle cells via the induction of the early gene NR4A1.

Neuropeptides activate human mast cell degranulation and chemokine production

PubMed Central

Kulka, Marianna; Sheen, Cecilia H; Tancowny, Brian P; Grammer, Leslie C; Schleimer, Robert P

2008-01-01

During neuronal-induced inflammation, mast cells may respond to stimuli such as neuropeptides in an FcεRI-independent manner. In this study, we characterized human mast cell responses to substance P (SP), nerve growth factor (NGF), calcitonin gene-related peptide (CGRP) and vasoactive intestinal polypeptide (VIP) and compared these responses to human mast cell responses to immunoglobulin E (IgE)/anti-IgE and compound 48/80. Primary cultured mast cells, generated from CD34+ progenitors in the presence of stem cell factor and interleukin-6 (IL-6), and human cultured mast cells (LAD2) were stimulated with these and other stimuli (gastrin, concanavalin A, radiocontrast media, and mannitol) and their degranulation and chemokine production was assessed. VIP and SP stimulated primary human mast cells and LAD cells to degranulate; gastrin, concanavalin A, radiocontrast media, mannitol, CGRP and NGF did not activate degranulation. While anti-IgE stimulation did not induce significant production of chemokines, stimulation with VIP, SP or compound 48/80 potently induced production of monocyte chemoattractant protein-1, inducible protein-10, monokine induced by interferon-γ (MIG), RANTES (regulated on activation, normal, T-cell expressed, and secreted) and IL-8. VIP, SP and compound 48/80 also activated release of tumour necrosis factor, IL-3 and granulocyte–macrophage colony-stimulating factor, but not IL-4, interferon-γ or eotaxin. Human mast cells expressed surface neurokinin 1 receptor (NK1R), NK2R, NK3R and VIP receptor type 2 (VPAC2) but not VPAC1 and activation of human mast cells by IgE/anti-IgE up-regulated expression of VPAC2, NK2R, and NK3R. These studies demonstrate the pattern of receptor expression and activation of mast cell by a host of G-protein coupled receptor ligands and suggest that SP and VIP activate a unique signalling pathway in human mast cells. These results are likely to have direct relevance to neuronally induced inflammatory diseases. PMID:17922833

Brain-derived neurotrophic factor and its receptors in Bergmann glia cells.

PubMed

Poblete-Naredo, Irais; Guillem, Alain M; Juárez, Claudia; Zepeda, Rossana C; Ramírez, Leticia; Caba, Mario; Hernández-Kelly, Luisa C; Aguilera, José; López-Bayghen, Esther; Ortega, Arturo

2011-12-01

Brain-derived neurotrophic factor is an abundant and widely distributed neurotrophin expressed in the Central Nervous System. It is critically involved in neuronal differentiation and survival. The expression of brain-derived neurotrophic factor and that of its catalytic active cognate receptor (TrkB) has been extensively studied in neuronal cells but their expression and function in glial cells is still controversial. Despite of this fact, brain-derived neurotrophic factor is released from astrocytes upon glutamate stimulation. A suitable model to study glia/neuronal interactions, in the context of glutamatergic synapses, is the well-characterized culture of chick cerebellar Bergmann glia cells. Using, this system, we show here that BDNF and its functional receptor are present in Bergmann glia and that BDNF stimulation is linked to the activation of the phosphatidyl-inositol 3 kinase/protein kinase C/mitogen-activated protein kinase/Activator Protein-1 signaling pathway. Accordingly, reverse transcription-polymerase chain reaction (RT-PCR) experiments predicted the expression of full-length and truncated TrkB isoforms. Our results suggest that Bergmann glia cells are able to express and respond to BDNF stimulation favoring the notion of their pivotal role in neuroprotection. Copyright © 2011 Elsevier B.V. All rights reserved.

Identification of the cellular receptor for anthrax toxin

NASA Astrophysics Data System (ADS)

Bradley, Kenneth A.; Mogridge, Jeremy; Mourez, Michael; Collier, R. John; Young, John A. T.

2001-11-01

The tripartite toxin secreted by Bacillus anthracis, the causative agent of anthrax, helps the bacterium evade the immune system and can kill the host during a systemic infection. Two components of the toxin enzymatically modify substrates within the cytosol of mammalian cells: oedema factor (OF) is an adenylate cyclase that impairs host defences through a variety of mechanisms including inhibiting phagocytosis; lethal factor (LF) is a zinc-dependent protease that cleaves mitogen-activated protein kinase kinase and causes lysis of macrophages. Protective antigen (PA), the third component, binds to a cellular receptor and mediates delivery of the enzymatic components to the cytosol. Here we describe the cloning of the human PA receptor using a genetic complementation approach. The receptor, termed ATR (anthrax toxin receptor), is a type I membrane protein with an extracellular von Willebrand factor A domain that binds directly to PA. In addition, a soluble version of this domain can protect cells from the action of the toxin.

Receptor-like Molecules on Human Intestinal Epithelial Cells Interact with an Adhesion Factor from Lactobacillus reuteri.

PubMed

Matsuo, Yosuke; Miyoshi, Yukihiro; Okada, Sanae; Satoh, Eiichi

2012-01-01

A surface protein of Lactobacillus reuteri, mucus adhesion-promoting protein (MapA), is considered to be an adhesion factor. MapA is expressed in L. reuteri strains and adheres to piglet gastric mucus, collagen type I, and human intestinal epithelial cells such as Caco-2. The aim of this study was to identify molecules that mediate the attachment of MapA from L. reuteri to the intestinal epithelial cell surface by investigating the adhesion of MapA to receptor-like molecules on Caco-2 cells. MapA-binding receptor-like molecules were detected in Caco-2 cell lysates by 2D-PAGE. Two proteins, annexin A13 (ANXA13) and paralemmin (PALM), were identified by MALDI TOF-MS. The results of a pull-down assay showed that MapA bound directly to ANXA13 and PALM. Fluorescence microscopy studies confirmed that MapA binding to ANXA13 and PALM was colocalized on the Caco-2 cell membrane. To evaluate whether ANXA13 and PALM are important for MapA adhesion, ANXA13 and PALM knockdown cell lines were established. The adhesion of MapA to the abovementioned cell lines was reduced compared with that to wild-type Caco-2 cells. These knockdown experiments established the importance of these receptor-like molecules in MapA adhesion.

Serum amyloid A stimulates macrophage foam cell formation via lectin-like oxidized low-density lipoprotein receptor 1 upregulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ha Young, E-mail: hayoung@skku.edu; Mitochondria Hub Regulation Center, Dong-A University, Busan 602-714; Kim, Sang Doo

2013-03-29

Highlights: ► SAA induced macrophage foam cell formation. ► SAA stimulated upregulation of lectin-like oxidized low-density lipoprotein receptor 1 (LOX1). ► SAA-induced LOX1 expression and foam cell formation is mediated by JNK/NF-κB signaling. ► HDL-conjugated SAA also stimulates foam cell formation via LOX1 upregulation. ► The finding reveals a novel mechanism of action of SAA in the pathogenesis of atherosclerosis. -- Abstract: Elevated levels of serum amyloid A (SAA) is a risk factor for cardiovascular diseases, however, the role of SAA in the pathophysiology of atherosclerosis remains unclear. Here we show that SAA induced macrophage foam cell formation. SAA-stimulated foammore » cell formation was mediated by c-jun N-terminal kinase (JNK) signaling. Moreover, both SAA and SAA-conjugated high density lipoprotein stimulated the expression of the important scavenger receptor lectin-like oxidized low-density lipoprotein receptor 1 (LOX1) via nuclear factor-κB (NF-κB). A LOX1 antagonist carrageenan significantly blocked SAA-induced foam cell formation, indicating that SAA promotes foam cell formation via LOX1 expression. Our findings therefore suggest that SAA stimulates foam cell formation via LOX1 induction, and thus likely contributes to atherogenesis.« less

New Chimeric Antigen Receptor Design for Solid Tumors

PubMed Central

Wang, Yuedi; Luo, Feifei; Yang, Jiao; Zhao, Chujun; Chu, Yiwei

2017-01-01

In recent years, chimeric antigen receptor (CAR) T-cell therapy has become popular in immunotherapy, particularly after its tremendous success in the treatment of lineage-restricted hematologic cancers. However, the application of CAR T-cell therapy for solid tumors has not reached its full potential because of the lack of specific tumor antigens and inhibitory factors in suppressive tumor microenvironment (TME) (e.g., programmed death ligand-1, myeloid-derived suppressor cells, and transforming growth factor-β). In this review, we include some limitations in CAR design, such as tumor heterogeneity, indefinite spatial distance between CAR T-cell and its target cell, and suppressive TME. We also summarize some new approaches to overcome these hurdles, including targeting neoantigens and/or multiple antigens at once and depleting some inhibitory factors. PMID:29312360

The anti-apoptotic activity associated with phosphatidylinositol transfer protein alpha activates the MAPK and Akt/PKB pathway.

PubMed

Schenning, Martijn; Goedhart, Joachim; Gadella, Theodorus W J; Avram, Diana; Wirtz, Karel W A; Snoek, Gerry T

2008-10-01

The conditioned medium (CM) from mouse NIH3T3 fibroblast cells overexpressing phosphatidylinositol transfer protein alpha (PI-TPalpha; SPIalpha cells) demonstrates an increased anti-apoptotic activity compared with CM from wild type NIH3T3 (wtNIH3T3) cells. As previously shown, the anti-apoptotic activity acts by activating a G protein-coupled receptor, most probably a cannabinoid 1 (CB1)-like receptor as the activity was blocked by both pertussis toxin and rimonabant [M. Schenning, C.M. van Tiel, D. Van Manen, J.C. Stam, B.M. Gadella, K.W. Wirtz and G.T. Snoek, Phosphatidylinositol transfer protein alpha regulates growth and apoptosis of NIH3T3 cells: involvement of a cannabinoid 1-like receptor, J. Lipid Res. 45 (2004) 1555-1564]. The CB1 receptor appears to be expressed in mouse fibroblast cells, at levels in the order SPIalpha>wtNIH3T3>SPIbeta cells (i.e. wild type cells overexpressing PI-TPbeta). Upon incubation of SPIbeta cells with the PI-TPalpha-dependent anti-apoptotic factors, both the ERK/MAP kinase and the Akt/PKB pathway are activated in a CB1 receptor dependent manner as shown by Western blotting. In addition, activation of ERK2 was also shown by EYFP-ERK2 translocation to the nucleus, as visualized by confocal laser scanning microscopy. The subsequent activation of the anti-apoptotic transcription factor NF-kappaB is in line with the increased resistance towards UV-induced apoptosis. On the other hand, receptor activation by CM from SPIalpha cells was not linked to phospholipase C activation as the YFP-labelled C2-domain of protein kinase C was not translocated to the plasma membrane of SPIbeta cells as visualized by confocal laser scanning microscopy.

Molecular targeting of growth factor receptor-bound 2 (Grb2) as an anti-cancer strategy.

PubMed

Dharmawardana, Pathirage G; Peruzzi, Benedetta; Giubellino, Alessio; Burke, Terrence R; Bottaro, Donald P

2006-01-01

Growth factor receptor-bound 2 (Grb2) is a ubiquitously expressed adapter protein that provides a critical link between cell surface growth factor receptors and the Ras signaling pathway. As such, it has been implicated in the oncogenesis of several important human malignancies. In addition to this function, research over the last decade has revealed other fundamental roles for Grb2 in cell motility and angiogenesis--processes that also contribute to tumor growth, invasiveness and metastasis. This functional profile makes Grb2 a high priority target for anti-cancer drug development. Knowledge of Grb2 protein structure, its component Src homology domains and their respective structure-function relationships has facilitated the rapid development of sophisticated drug candidates that can penetrate cells, bind Grb2 with high affinity and potently antagonize Grb2 signaling. These novel compounds offer considerable promise in our growing arsenal of rationally designed anti-cancer therapeutics.

c-MPL provides tumor-targeted T-cell receptor-transgenic T cells with costimulation and cytokine signals.

PubMed

Nishimura, Christopher D; Brenner, Daniel A; Mukherjee, Malini; Hirsch, Rachel A; Ott, Leah; Wu, Meng-Fen; Liu, Hao; Dakhova, Olga; Orange, Jordan S; Brenner, Malcolm K; Lin, Charles Y; Arber, Caroline

2017-12-21

Adoptively transferred T-cell receptor (TCR)-engineered T cells depend on host-derived costimulation and cytokine signals for their full and sustained activation. However, in patients with cancer, both signals are frequently impaired. Hence, we developed a novel strategy that combines both essential signals in 1 transgene by expressing the nonlymphoid hematopoietic growth factor receptor c-MPL (myeloproliferative leukemia), the receptor for thrombopoietin (TPO), in T cells. c-MPL signaling activates pathways shared with conventional costimulatory and cytokine receptor signaling. Thus, we hypothesized that host-derived TPO, present in the tumor microenvironment, or pharmacological c-MPL agonists approved by the US Food and Drug Administration could deliver both signals to c-MPL-engineered TCR-transgenic T cells. We found that c-MPL + polyclonal T cells expand and proliferate in response to TPO, and persist longer after adoptive transfer in immunodeficient human TPO-transgenic mice. In TCR-transgenic T cells, c-MPL activation enhances antitumor function, T-cell expansion, and cytokine production and preserves a central memory phenotype. c-MPL signaling also enables sequential tumor cell killing, enhances the formation of effective immune synapses, and improves antileukemic activity in vivo in a leukemia xenograft model. We identify the type 1 interferon pathway as a molecular mechanism by which c-MPL mediates immune stimulation in T cells. In conclusion, we present a novel immunotherapeutic strategy using c-MPL-enhanced transgenic T cells responding to either endogenously produced TPO (a microenvironment factor in hematologic malignancies) or c-MPL-targeted pharmacological agents. © 2017 by The American Society of Hematology.

Rational Design of Potent Antagonists to the Human Growth Hormone Receptor

NASA Astrophysics Data System (ADS)

Fuh, Germaine; Cunningham, Brian C.; Fukunaga, Rikiro; Nagata, Shigekazu; Goeddel, David V.; Wells, James A.

1992-06-01

A hybrid receptor was constructed that contained the extracellular binding domain of the human growth hormone (hGH) receptor linked to the transmembrane and intracellular domains of the murine granulocyte colony-stimulating factor receptor. Addition of hGH to a myeloid leukemia cell line (FDC-P1) that expressed the hybrid receptor caused proliferation of these cells. The mechanism for signal transduction of the hybrid receptor required dimerization because monoclonal antibodies to the hGH receptor were agonists whereas their monovalent fragments were not. Receptor dimerization occurs sequentially-a receptor binds to site 1 on hGH, and then a second receptor molecule binds to site 2 on hGH. On the basis of this sequential mechanism, which may occur in many other cytokine receptors, inactive hGH analogs were designed that were potent antagonists to hGH-induced cell proliferation. Such antagonists could be useful for treating clinical conditions of hGH excess, such as acromegaly.

Quantification of growth factor signaling and pathway cross talk by live-cell imaging

PubMed Central

Gross, Sean M.

2017-01-01

Peptide growth factors stimulate cellular responses through activation of their transmembrane receptors. Multiple intracellular signaling cascades are engaged following growth factor–receptor binding, leading to short- and long-term biological effects. Each receptor-activated signaling pathway does not act in isolation but rather interacts at different levels with other pathways to shape signaling networks that are distinctive for each growth factor. To gain insights into the specifics of growth factor-regulated interactions among different signaling cascades, we developed a HeLa cell line stably expressing fluorescent live-cell imaging reporters that are readouts for two major growth factor-stimulated pathways, Ras–Raf–Mek–ERK and phosphatidylinositol (PI) 3-kinase–Akt. Incubation of cells with epidermal growth factor (EGF) resulted in rapid, robust, and sustained ERK signaling but shorter-term activation of Akt. In contrast, hepatocyte growth factor induced sustained Akt signaling but weak and short-lived ERK activity, and insulin-like growth factor-I stimulated strong long-term Akt responses but negligible ERK signaling. To address potential interactions between signaling pathways, we employed specific small-molecule inhibitors. In cells incubated with EGF or platelet-derived growth factor-AA, Raf activation and the subsequent stimulation of ERK reduced Akt signaling, whereas Mek inhibition, which blocked ERK activation, enhanced Akt and turned transient effects into sustained responses. Our results reveal that individual growth factors initiate signaling cascades that vary markedly in strength and duration and demonstrate in living cells the dramatic effects of cross talk from Raf and Mek to PI 3-kinase and Akt. Our data further indicate how specific growth factors can encode distinct cellular behaviors by promoting complex interactions among signaling pathways. PMID:28100485

A selective antagonist reveals a potential role of G protein-coupled receptor 55 in platelet and endothelial cell function.

PubMed

Kargl, Julia; Brown, Andrew J; Andersen, Liisa; Dorn, Georg; Schicho, Rudolf; Waldhoer, Maria; Heinemann, Akos

2013-07-01

The G protein-coupled receptor 55 (GPR55) is a lysophosphatidylinositol (LPI) receptor that is also responsive to certain cannabinoids. Although GPR55 has been implicated in several (patho)physiologic functions, its role remains enigmatic owing mainly to the lack of selective GPR55 antagonists. Here we show that the compound CID16020046 ((4-[4-(3-hydroxyphenyl)-3-(4-methylphenyl)-6-oxo-1H,4H,5H,6H-pyrrolo[3,4-c]pyrazol-5-yl] benzoic acid) is a selective GPR55 antagonist. In yeast cells expressing human GPR55, CID16020046 antagonized agonist-induced receptor activation. In human embryonic kidney (HEK293) cells stably expressing human GPR55, the compound behaved as an antagonist on LPI-mediated Ca²⁺ release and extracellular signal-regulated kinases activation, but not in HEK293 cells expressing cannabinoid receptor 1 or 2 (CB₁ or CB₂). CID16020046 concentration dependently inhibited LPI-induced activation of nuclear factor of activated T-cells (NFAT), nuclear factor κ of activated B cells (NF-κB) and serum response element, translocation of NFAT and NF-κB, and GPR55 internalization. It reduced LPI-induced wound healing in primary human lung microvascular endothelial cells and reversed LPI-inhibited platelet aggregation, suggesting a novel role for GPR55 in platelet and endothelial cell function. CID16020046 is therefore a valuable tool to study GPR55-mediated mechanisms in primary cells and tissues.

Granulocyte-colony stimulating factor and stem cell factor are the crucial factors in long-term culture of human primitive hematopoietic cells supported by a murine stromal cell line.

PubMed

Nishi, N; Ishikawa, R; Inoue, H; Nishikawa, M; Kakeda, M; Yoneya, T; Tsumura, H; Ohashi, H; Yamaguchi, Y; Motoki, K; Sudo, T; Mori, K J

1996-09-01

The findings that murine marrow stromal cell line MS-5 supported the proliferation of human lineage-negative (Lin-) CD34+CD38- bone marrow cells in long-term culture have been reported. In this study, we analyzed this proliferating activity of MS-5-conditioned medium (CM) on human primitive hematopoietic cells. When Lin-CD34+CD38- cells of normal human cord blood cells were co-cultured with MS-5, colony forming cells (CFCs) were maintained over 7 weeks in vitro. Prevention of contact between MS-5 and Lin-CD34+CD38- cells by using membrane filter (0.45 micron) was negligible for this activity. This indicated that the activity of MS-5 on human primitive hematopoietic cells is a soluble factor(s) secreted from MS-5, which is not induced by the contact between MS-5 and Lin-CD34+CD38- cells. We tried to purify this soluble activity. An active material with a molecular weight of about 150 kDa, determined by gel filtration chromatography, solely supported the growth of Lin-CD34+CD38- cells and Mo7e, a human megakaryocytic cell line. This activity not only reacted with anti-mouse stem cell factor (mSCF) antibody on Western blots, but it was also neutralized in the presence of anti-mSCF antibody. Another active material with a molecular weight of about 20-30 kDa synergized with mSCF to stimulate the growth of Lin-CD34+CD38- cells but failed to do so alone, although this synergy was inhibited in the presence of soluble mouse granulocyte-colony stimulating factor (mG-CSF) receptor, which is a chimeric protein consisting of the extracellular domain of mG-CSF receptor and the Fe region of human IgG1. In addition, the latter molecule supported the growth of the G-CSF dependent cell line FD/GR3, which is a murine myeloid leukemia cell line, FDC-P2, transfected with mG-CSF receptor cDNA. Adding of anti-mSCF antibody and soluble mG-CSF receptor to the culture completely abrogated the activity of MS-5-CM. Recombinant (r) mSCF and rmG-CSF had synergistic activity on the growth of Lin-CD34+CD38- cells. These results indicated that the activity on Lin-CD34+CD38- cells included in MS-5-CM is based upon the synergistic effects of mSCF and mG-CSF.

Expression and regulation of CNTF receptor-alpha in the in situ and in oculo grafted adult rat adrenal medulla.

PubMed

Förander, P; Brené, S; Strömberg, I

2000-02-28

Cultured and transplanted adrenal medullary cells respond to ciliary neurotrophic factor (CNTF) with neurite formation and improved cell survival although the presence of the CNTF receptor-alpha (CNTFRalpha) has been unclear. This study show that CNTFRalpha mRNA was expressed in the postnatal day 1 as well as in the adult rat adrenal medulla. The highest CNTFRalpha mRNA signal was found in the ganglion cells of the adrenal medulla. After transplantation of adrenal medullary tissue the CNTFRalpha mRNA levels were down-regulated in the chromaffin cells. CNTF treatment of grafts did not normalize the receptor levels, but treatment with nerve growth factor (NGF) did. Thus, we demonstrate that CNTFRalpha mRNA is expressed in adrenal medulla, the levels becomes down-regulated after transplantation, but normalized after treatment with NGF.

Epidermal growth factor receptor expression in primary cultured human colorectal carcinoma cells.

PubMed Central

Tong, W. M.; Ellinger, A.; Sheinin, Y.; Cross, H. S.

1998-01-01

In situ hybridization on human colon tissue demonstrates that epidermal growth factor receptor (EGFR) mRNA expression is strongly increased during tumour progression. To obtain test systems to evaluate the relevance of growth factor action during carcinogenesis, primary cultures from human colorectal carcinomas were established. EGFR distribution was determined in 2 of the 27 primary cultures and was compared with that in well-defined subclones derived from the Caco-2 cell line, which has the unique property to differentiate spontaneously in vitro in a manner similar to normal enterocytes. The primary carcinoma-derived cells had up to three-fold higher total EGFR levels than the Caco-2 subclones and a basal mitotic rate at least fourfold higher. The EGFR affinity constant is 0.26 nmol l(-1), which is similar to that reported in Caco-2 cells. The proliferation rate of Caco-2 cells is mainly induced by EGF from the basolateral cell surface where the majority of receptors are located, whereas primary cultures are strongly stimulated from the apical side also. This corresponds to a three- to fivefold higher level of EGFR at the apical cell surface. This redistribution of EGFR to apical plasma membranes in advanced colon carcinoma cells suggests that autocrine growth factors in the colon lumen may play a significant role during tumour progression. Images Figure 1 Figure 2 PMID:9667648

The Industrial Chemical Bisphenol A (BPA) Interferes with Proliferative Activity and Development of Steroidogenic Capacity in Rat Leydig Cells1

PubMed Central

Nanjappa, Manjunatha K.; Simon, Liz; Akingbemi, Benson T.

2012-01-01

ABSTRACT The presence of bisphenol A (BPA) in consumer products has raised concerns about potential adverse effects on reproductive health. Testicular Leydig cells are the predominant source of the male sex steroid hormone testosterone, which supports the male phenotype. The present report describes the effects of developmental exposure of male rats to BPA by gavage of pregnant and lactating Long-Evans dams at 2.5 and 25 μg/kg body weight from Gestational Day 12 to Day 21 postpartum. This exposure paradigm stimulated Leydig cell division in the prepubertal period and increased Leydig cell numbers in the testes of adult male rats at 90 days. Observations from in vitro experiments confirmed that BPA acts directly as a mitogen in Leydig cells. However, BPA-induced proliferative activity in vivo is possibly mediated by several factors, such as 1) protein kinases (e.g., mitogen-activated protein kinases or MAPK), 2) growth factor receptors (e.g., insulin-like growth factor 1 receptor-beta and epidermal growth factor receptors), and 3) the Sertoli cell-secreted anti-Mullerian hormone (also called Mullerian inhibiting substance). On the other hand, BPA suppressed protein expression of the luteinizing hormone receptor (LHCGR) and the 17beta-hydroxysteroid dehydrogenase enzyme (HSD17B3), thereby decreasing androgen secretion by Leydig cells. We interpret these findings to mean that the likely impact of deficits in androgen secretion on serum androgen levels following developmental exposure to BPA is alleviated by increased Leydig cell numbers. Nevertheless, the present results reinforce the view that BPA causes biological effects at environmentally relevant exposure levels and its presence in consumer products potentially has implication for public health. PMID:22302688

Effect of propofol on androgen receptor activity in prostate cancer cells.

PubMed

Tatsumi, Kenichiro; Hirotsu, Akiko; Daijo, Hiroki; Matsuyama, Tomonori; Terada, Naoki; Tanaka, Tomoharu

2017-08-15

Androgen receptor is a nuclear receptor and transcription factor activated by androgenic hormones. Androgen receptor activity plays a pivotal role in the development and progression of prostate cancer. Although accumulating evidence suggests that general anesthetics, including opioids, affect cancer cell growth and impact patient prognosis, the effect of those drugs on androgen receptor in prostate cancer is not clear. The purpose of this study was to investigate the effect of the general anesthetic propofol on androgen receptor activity in prostate cancer cells. An androgen-dependent human prostate cancer cell line (LNCaP) was stimulated with dihydrotestosterone (DHT) and exposed to propofol. The induction of androgen receptor target genes was investigated using real-time reverse transcription polymerase chain reaction, and androgen receptor protein levels and localization patterns were analyzed using immunoblotting and immunofluorescence assays. The effect of propofol on the proliferation of LNCaP cells was analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Propofol significantly inhibited DHT-induced expression of androgen receptor target genes in a dose- and time-dependent manner, and immunoblotting and immunofluorescence assays indicated that propofol suppressed nuclear levels of androgen receptor proteins. Exposure to propofol for 24h suppressed the proliferation of LNCaP cells, whereas 4h of exposure did not exert significant effects. Together, our results indicate that propofol suppresses nuclear androgen receptor protein levels, and inhibits androgen receptor transcriptional activity and proliferation in LNCaP cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Insights into GABA receptor signalling in TM3 Leydig cells.

PubMed

Doepner, Richard F G; Geigerseder, Christof; Frungieri, Monica B; Gonzalez-Calvar, Silvia I; Calandra, Ricardo S; Raemsch, Romi; Fohr, Karl; Kunz, Lars; Mayerhofer, Artur

2005-01-01

Gamma-aminobutyric acid (GABA) is an emerging signalling molecule in endocrine organs, since it is produced by endocrine cells and acts via GABA(A) receptors in a paracrine/autocrine fashion. Testicular Leydig cells are producers and targets for GABA. These cells express GABA(A) receptor subunits and in the murine Leydig cell line TM3 pharmacological activation leads to increased proliferation. The signalling pathway of GABA in these cells is not known in this study. We therefore attempted to elucidate details of GABA(A) signalling in TM3 and adult mouse Leydig cells using several experimental approaches. TM3 cells not only express GABA(A )receptor subunits, but also bind the GABA agonist [(3)H]muscimol with a binding affinity in the range reported for other endocrine cells (K(d) = 2.740 +/- 0.721 nM). However, they exhibit a low B(max) value of 28.08 fmol/mg protein. Typical GABA(A) receptor-associated events, including Cl(-) currents, changes in resting membrane potential, intracellular Ca(2+) or cAMP, were not measurable with the methods employed in TM3 cells, or, as studied in part, in primary mouse Leydig cells. GABA or GABA(A) agonist isoguvacine treatment resulted in increased or decreased levels of several mRNAs, including transcription factors (c-fos, hsf-1, egr-1) and cell cycle-associated genes (Cdk2, cyclin D1). In an attempt to verify the cDNA array results and because egr-1 was recently implied in Leydig cell development, we further studied this factor. RT-PCR and Western blotting confirmed a time-dependent regulation of egr-1 in TM3. In the postnatal testis egr-1 was seen in cytoplasmic and nuclear locations of developing Leydig cells, which bear GABA(A) receptors and correspond well to TM3 cells. Thus, GABA acts via an atypical novel signalling pathway in TM3 cells. Further details of this pathway remain to be elucidated. Copyright (c) 2005 S. Karger AG, Basel.

Characterization of the growth of murine fibroblasts that express human insulin receptors. II. Interaction of insulin with other growth factors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Randazzo, P.A.; Jarett, L.

1990-09-01

The effects of insulin-like growth factor-1 (IGF-1), epidermal growth factor (EGF), platelet-derived growth factor (PDGF), and insulin on DNA synthesis were studied in murine fibroblasts transfected with an expression vector containing human insulin receptor cDNA (NIH 3T3/HIR) and the parental NIH 3T3 cells. In NIH 3T3/HIR cells, individual growth factors in serum-free medium stimulated DNA synthesis with the following relative efficacies: insulin greater than or equal to 10% fetal calf serum greater than PDGF greater than IGF-1 much greater than EGF. In comparison, the relative efficacies of these factors in stimulating DNA synthesis by NIH 3T3 cells were 10% fetalmore » calf serum greater than PDGF greater than EGF much greater than IGF-1 = insulin. In NIH 3T3/HIR cells, EGF was synergistic with 1-10 ng/ml insulin but not with 100 ng/ml insulin or more. Synergy of PDGF or IGF-1 with insulin was not detected. In the parental NIH 3T3 cells, insulin and IGF-1 were found to be synergistic with EGF (1 ng/ml), PDGF (100 ng/ml), and PDGF plus EGF. In NIH 3T3/HIR cells, the lack of interaction of insulin with other growth factors was also observed when the percentage of cells synthesizing DNA was examined. Despite insulin's inducing only 60% of NIH 3T3/HIR cells to incorporate thymidine, addition of PDGF, EGF, or PDGF plus EGF had no further effect. In contrast, combinations of growth factors resulted in 95% of the parental NIH 3T3 cells synthesizing DNA. The independence of insulin-stimulated DNA synthesis from other mitogens in the NIH 3T3/HIR cells is atypical for progression factor-stimulated DNA synthesis and is thought to be partly the result of insulin receptor expression in an inappropriate context or quantity.« less

Macrophages control vascular stem/progenitor cell plasticity through tumor necrosis factor-α-mediated nuclear factor-κB activation.

PubMed

Wong, Mei Mei; Chen, Yikuan; Margariti, Andriani; Winkler, Bernhard; Campagnolo, Paola; Potter, Claire; Hu, Yanhua; Xu, Qingbo

2014-03-01

Vascular lineage differentiation of stem/progenitor cells can contribute to both tissue repair and exacerbation of vascular diseases such as in vein grafts. The role of macrophages in controlling vascular progenitor differentiation is largely unknown and may play an important role in graft development. This study aims to identify the role of macrophages in vascular stem/progenitor cell differentiation and thereafter elucidate the mechanisms that are involved in the macrophage- mediated process. We provide in vitro evidence that macrophages can induce endothelial cell (EC) differentiation of the stem/progenitor cells while simultaneously inhibiting their smooth muscle cell differentiation. Mechanistically, both effects were mediated by macrophage-derived tumor necrosis factor-α (TNF-α) via TNF-α receptor 1 and canonical nuclear factor-κB activation. Although the overexpression of p65 enhanced EC (or attenuated smooth muscle cell) differentiation, p65 or TNF-α receptor 1 knockdown using lentiviral short hairpin RNA inhibited EC (or rescued smooth muscle cell) differentiation in response to TNF-α. Furthermore, TNF-α-mediated EC differentiation was driven by direct binding of nuclear factor-κB (p65) to specific VE-cadherin promoter sequences. Subsequent experiments using an ex vivo decellularized vessel scaffold confirmed an increase in the number of ECs and reduction in smooth muscle cell marker expression in the presence of TNF-α. The lack of TNF-α in a knockout mouse model of vein graft decreased endothelialization and significantly increased thrombosis formation. Our study highlights the role of macrophages in directing vascular stem/progenitor cell lineage commitment through TNF-α-mediated TNF-α receptor 1 and nuclear factor-κB activation that is likely required for endothelial repair in vascular diseases such as vein graft.

Congestive Heart Failure During Osimertinib Treatment for Epidermal Growth Factor Receptor (EGFR)-mutant Non-small Cell Lung Cancer (NSCLC).

PubMed

Watanabe, Hiromi; Ichihara, Eiki; Kano, Hirohisa; Ninomiya, Kiichiro; Tanimoto, Mitsune; Kiura, Katsuyuki

2017-08-15

We herein report a case of congestive heart failure which developed during osimertinib treatment. A 78-year-old woman presented with mild exertional dyspnea three weeks after starting osimertinib for the treatment of epidermal growth factor receptor (EGFR) T790M-positive non-small cell lung cancer. She was diagnosed with congestive heart failure caused by the osimertinib. In contrast to trastuzumab, a human epidermal growth factor receptor 2 (HER2) monoclonal antibody that often causes cardiac dysfunction, the causal relationship between osimertinib and cardiotoxicity has so far received little attention and thus remains unclear. However, it inhibits HER2 in addition to mutant EGFR, thereby potentially causing cardiotoxicity.

Congestive Heart Failure During Osimertinib Treatment for Epidermal Growth Factor Receptor (EGFR)-mutant Non-small Cell Lung Cancer (NSCLC)

PubMed Central

Watanabe, Hiromi; Ichihara, Eiki; Kano, Hirohisa; Ninomiya, Kiichiro; Tanimoto, Mitsune; Kiura, Katsuyuki

2017-01-01

We herein report a case of congestive heart failure which developed during osimertinib treatment. A 78-year-old woman presented with mild exertional dyspnea three weeks after starting osimertinib for the treatment of epidermal growth factor receptor (EGFR) T790M-positive non-small cell lung cancer. She was diagnosed with congestive heart failure caused by the osimertinib. In contrast to trastuzumab, a human epidermal growth factor receptor 2 (HER2) monoclonal antibody that often causes cardiac dysfunction, the causal relationship between osimertinib and cardiotoxicity has so far received little attention and thus remains unclear. However, it inhibits HER2 in addition to mutant EGFR, thereby potentially causing cardiotoxicity. PMID:28781309

NEU3 Sialidase Is Activated under Hypoxia and Protects Skeletal Muscle Cells from Apoptosis through the Activation of the Epidermal Growth Factor Receptor Signaling Pathway and the Hypoxia-inducible Factor (HIF)-1α

PubMed Central

Scaringi, Raffaella; Piccoli, Marco; Papini, Nadia; Cirillo, Federica; Conforti, Erika; Bergante, Sonia; Tringali, Cristina; Garatti, Andrea; Gelfi, Cecilia; Venerando, Bruno; Menicanti, Lorenzo; Tettamanti, Guido; Anastasia, Luigi

2013-01-01

NEU3 sialidase, a key enzyme in ganglioside metabolism, is activated under hypoxic conditions in cultured skeletal muscle cells (C2C12). NEU3 up-regulation stimulates the EGF receptor signaling pathway, which in turn activates the hypoxia-inducible factor (HIF-1α), resulting in a final increase of cell survival and proliferation. In the same cells, stable overexpression of sialidase NEU3 significantly enhances cell resistance to hypoxia, whereas stable silencing of the enzyme renders cells more susceptible to apoptosis. These data support the working hypothesis of a physiological role played by NEU3 sialidase in protecting cells from hypoxic stress and may suggest new directions in the development of therapeutic strategies against ischemic diseases, particularly of the cerebro-cardiovascular system. PMID:23209287

NEU3 sialidase is activated under hypoxia and protects skeletal muscle cells from apoptosis through the activation of the epidermal growth factor receptor signaling pathway and the hypoxia-inducible factor (HIF)-1α.

PubMed

Scaringi, Raffaella; Piccoli, Marco; Papini, Nadia; Cirillo, Federica; Conforti, Erika; Bergante, Sonia; Tringali, Cristina; Garatti, Andrea; Gelfi, Cecilia; Venerando, Bruno; Menicanti, Lorenzo; Tettamanti, Guido; Anastasia, Luigi

2013-02-01

NEU3 sialidase, a key enzyme in ganglioside metabolism, is activated under hypoxic conditions in cultured skeletal muscle cells (C2C12). NEU3 up-regulation stimulates the EGF receptor signaling pathway, which in turn activates the hypoxia-inducible factor (HIF-1α), resulting in a final increase of cell survival and proliferation. In the same cells, stable overexpression of sialidase NEU3 significantly enhances cell resistance to hypoxia, whereas stable silencing of the enzyme renders cells more susceptible to apoptosis. These data support the working hypothesis of a physiological role played by NEU3 sialidase in protecting cells from hypoxic stress and may suggest new directions in the development of therapeutic strategies against ischemic diseases, particularly of the cerebro-cardiovascular system.

Biophysically inspired model for functionalized nanocarrier adhesion to cell surface: roles of protein expression and mechanical factors

NASA Astrophysics Data System (ADS)

Ramakrishnan, N.; Tourdot, Richard W.; Eckmann, David M.; Ayyaswamy, Portonovo S.; Muzykantov, Vladimir R.; Radhakrishnan, Ravi

2016-06-01

In order to achieve selective targeting of affinity-ligand coated nanoparticles to the target tissue, it is essential to understand the key mechanisms that govern their capture by the target cell. Next-generation pharmacokinetic (PK) models that systematically account for proteomic and mechanical factors can accelerate the design, validation and translation of targeted nanocarriers (NCs) in the clinic. Towards this objective, we have developed a computational model to delineate the roles played by target protein expression and mechanical factors of the target cell membrane in determining the avidity of functionalized NCs to live cells. Model results show quantitative agreement with in vivo experiments when specific and non-specific contributions to NC binding are taken into account. The specific contributions are accounted for through extensive simulations of multivalent receptor-ligand interactions, membrane mechanics and entropic factors such as membrane undulations and receptor translation. The computed NC avidity is strongly dependent on ligand density, receptor expression, bending mechanics of the target cell membrane, as well as entropic factors associated with the membrane and the receptor motion. Our computational model can predict the in vivo targeting levels of the intracellular adhesion molecule-1 (ICAM1)-coated NCs targeted to the lung, heart, kidney, liver and spleen of mouse, when the contributions due to endothelial capture are accounted for. The effect of other cells (such as monocytes, etc.) do not improve the model predictions at steady state. We demonstrate the predictive utility of our model by predicting partitioning coefficients of functionalized NCs in mice and human tissues and report the statistical accuracy of our model predictions under different scenarios.

Defects in subventricular zone pigmented epithelium-derived factor niche signaling in the senescence-accelerated mouse prone-8.

PubMed

Castro-Garcia, Paola; Díaz-Moreno, María; Gil-Gas, Carmen; Fernández-Gómez, Francisco J; Honrubia-Gómez, Paloma; Álvarez-Simón, Carmen Belén; Sánchez-Sánchez, Francisco; Cano, Juan Carlos Castillo; Almeida, Francisco; Blanco, Vicente; Jordán, Joaquín; Mira, Helena; Ramírez-Castillejo, Carmen

2015-04-01

We studied potential changes in the subventricular zone (SVZ) stem cell niche of the senescence-accelerated mouse prone-8 (SAM-P8) aging model. Bromodeoxyuridine (BrdU) assays with longtime survival revealed a lower number of label-retaining stem cells in the SAM-P8 SVZ compared with the SAM-Resistant 1 (SAM-R1) control strain. We also found that in SAM-P8 niche signaling is attenuated and the stem cell pool is less responsive to the self-renewal niche factor pigmented epithelium-derived factor (PEDF). Protein analysis demonstrated stable amounts of the PEDF ligand in the SAM-P8 SVZ niche; however, SAM-P8 stem cells present a significant expression decrease of patatin-like phospholipase domain containing 2, a receptor for PEDF (PNPLA2-PEDF) receptor, but not of laminin receptor (LR), a receptor for PEDF (LR-PEDF) receptor. We observed changes in self-renewal related genes (hairy and enhancer of split 1 (Hes1), hairy and enhancer of split 1 (Hes5), Sox2] and report that although these genes are down-regulated in SAM-P8, differentiation genes (Pax6) are up-regulated and neurogenesis is increased. Finally, sheltering mammalian telomere complexes might be also involved given a down-regulation of telomeric repeat binding factor 1 (Terf1) expression was observed in SAM-P8 at young age periods. Differences between these 2 models, SAM-P8 and SAM-R1 controls, have been previously detected at more advanced ages. We now describe alterations in the PEDF signaling pathway and stem cell self-renewal at a very young age, which could be involved in the premature senescence observed in the SAM-P8 model. © FASEB.

Antiangiogenic drugs synergize with a membrane macrophage colony-stimulating factor-based tumor vaccine to therapeutically treat rats with an established malignant intracranial glioma.

PubMed

Jeffes, Edward W B; Zhang, Jian Gang; Hoa, Neil; Petkar, Animesh; Delgado, Christina; Chong, Samuel; Obenaus, Andre; Sanchez, Ramon; Khalaghizadeh, Sakineh; Khomenko, Tetyana; Knight, Brandon A; Alipanah, Reza; Nguyen, Tuong-Vi; Shah, Chirag; Vohra, Seema; Zhuang, Jing-Li; Liu, Jessie; Wepsic, H Terry; Jadus, Martin R

2005-03-01

Combining a T9/9L glioma vaccine, expressing the membrane form of M-CSF, with a systemic antiangiogenic drug-based therapy theoretically targeted toward growth factor receptors within the tumor's vasculature successfully treated >90% of the rats bearing 7-day-old intracranial T9/9L gliomas. The antiangiogenic drugs included (Z)-3-[4-(dimethylamino)benzylidenyl]indolin-2-one (a platelet-derived growth factor receptor beta and a fibroblast growth factor receptor 1 kinase inhibitor) and oxindole (a vascular endothelial growth factor receptor 2 kinase inhibitor). A total of 20-40% of the animals treated with the antiangiogenic drugs alone survived, while all nontreated controls and tumor vaccine-treated rats died within 40 days. In vitro, these drugs inhibited endothelial cells from proliferating in response to the angiogenic factors produced by T9/9L glioma cells and prevented endothelial cell tubulogenesis. FITC-labeled tomato lectin staining demonstrated fewer and constricted blood vessels within the intracranial tumor after drug therapy. Magnetic resonance imaging demonstrated that the intracranial T9 glioma grew much slower in the presence of these antiangiogenic drugs. These drugs did not affect in vitro glioma cell growth nor T cell mitogenesis. Histological analysis revealed that the tumor destruction occurred at the margins of the tumor, where there was a heavy lymphocytic infiltrate. Real-time PCR showed more IL-2-specific mRNA was present within the gliomas in the vaccinated rats treated with the drugs. Animals that rejected the established T9/9L glioma by the combination therapy proved immune against an intracranial rechallenge by T9/9L glioma, but showed no resistance to an unrelated MADB106 breast cancer.

Gab-family adapter proteins act downstream of cytokine and growth factor receptors and T- and B-cell antigen receptors.

PubMed

Nishida, K; Yoshida, Y; Itoh, M; Fukada, T; Ohtani, T; Shirogane, T; Atsumi, T; Takahashi-Tezuka, M; Ishihara, K; Hibi, M; Hirano, T

1999-03-15

We previously found that the adapter protein Gab1 (110 kD) is tyrosine-phosphorylated and forms a complex with SHP-2 and PI-3 kinase upon stimulation through either the interleukin-3 receptor (IL-3R) or gp130, the common receptor subunit of IL-6-family cytokines. In this report, we identified another adapter molecule (100 kD) interacting with SHP-2 and PI-3 kinase in response to various stimuli. The molecule displays striking homology to Gab1 at the amino acid level; thus, we named it Gab2. It contains a PH domain, proline-rich sequences, and tyrosine residues that bind to SH2 domains when they are phosphorylated. Gab1 is phosphorylated on tyrosine upon stimulation through the thrombopoietin receptor (TPOR), stem cell factor receptor (SCFR), and T-cell and B-cell antigen receptors (TCR and BCR, respectively), in addition to IL-3R and gp130. Tyrosine phosphorylation of Gab2 was induced by stimulation through gp130, IL-2R, IL-3R, TPOR, SCFR, and TCR. Gab1 and Gab2 were shown to be substrates for SHP-2 in vitro. Overexpression of Gab2 enhanced the gp130 or Src-related kinases-mediated ERK2 activation as that of Gab1 did. These data indicate that Gab-family molecules act as adapters for transmitting various signals.

Modeling the Effects of HER/ErbB1-3 Coexpression on Receptor Dimerization and Biological Response

PubMed Central

Shankaran, Harish; Wiley, H. Steven; Resat, Haluk

2006-01-01

The human epidermal growth factor receptor (HER/ErbB) system comprises the epidermal growth factor receptor (EGFR/HER1) and three other homologs, namely HERs 2–4. This receptor system plays a critical role in cell proliferation and differentiation and receptor overexpression has been associated with poor prognosis in cancers of the epithelium. Here, we examine the effect of coexpressing varying levels of HERs 1–3 on the receptor dimerization patterns using a detailed kinetic model for HER/ErbB dimerization and trafficking. Our results indicate that coexpression of EGFR with HER2 or HER3 biases signaling to the cell surface and retards signal downregulation. In addition, simultaneous coexpression of HERs 1–3 leads to an abundance of HER2-HER3 heterodimers, which are known to be potent inducers of cell growth and transformation. Our new approach to use parameter dependence analysis in experimental design reveals that measurements of HER3 phosphorylation and HER2 internalization ratio may prove to be especially useful for the estimation of critical model parameters. Further, we examine the effect of receptor dimerization patterns on biological response using a simple phenomenological model. Results indicate that coexpression of EGFR with HER2 and HER3 at low to moderate levels may enable cells to match the response of a high HER2 expresser. PMID:16533841

Evidence That Graves' Ophthalmopathy Immunoglobulins Do Not Directly Activate IGF-1 Receptors.

PubMed

Marcus-Samuels, Bernice; Krieger, Christine C; Boutin, Alisa; Kahaly, George J; Neumann, Susanne; Gershengorn, Marvin C

2018-05-01

Graves' ophthalmopathy (GO) pathogenesis involves thyrotropin (TSH) receptor (TSHR)-stimulating autoantibodies. Whether there are autoantibodies that directly stimulate insulin-like growth factor 1 receptors (IGF-1Rs), stimulating insulin-like growth factor receptor antibodies (IGFRAbs), remains controversial. This study attempted to determine whether there are stimulating IGFRAbs in patients with GO. Immunoglobulins (Igs) were purified from normal volunteers (NV-Igs) and patients with GO (GO-Igs). The effects of TSH, IGF-1, NV-Igs, and GO-Igs on pAKT and pERK1/2, members of pathways used by IGF-1R and TSHR, were compared in orbital fibroblasts from GO patients (GOFs) and U2OS-TSHR cells overexpressing TSHRs, and U2OS cells that express TSHRs at very low endogenous levels. U2OS-TSHR and U2OS cells were used because GOFs are not easily manipulated using molecular techniques such as transfection, and U2OS cells because they express TSHRs at levels that do not measurably stimulate signaling. Thus, comparing U2OS-TSHR and U2OS cells permits specifically distinguishing signaling mediated by the TSHR and IGF-1R. In GOFs, all GO-Igs stimulated pERK1/2 formation and 69% stimulated pAKT. In U2OS-TSHR cells, 15% of NV-IGs and 83% of GO-Igs stimulated increases in pERK1/2, whereas all NV-Igs and GO-Igs stimulated increases in pAKT. In U2OS cells, 70% of GO-Igs stimulated small increases in pAKT. Knockdown of IGF-1R caused a 65 ± 6.3% decrease in IGF-1-stimulated pAKT but had no effect on GO-Igs stimulation of pAKT. Thus, GO-Igs contain factor(s) that stimulate pAKT formation. However, this factor(s) does not directly activate IGF-1R. Based on the findings analyzing these two signaling pathways, it is concluded there is no evidence of stimulating IGFRAbs in GO patients.

Cytotoxic-T-lymphocyte antigen 4 receptor signaling for lymphocyte adhesion is mediated by C3G and Rap1.

PubMed

Kloog, Yoel; Mor, Adam

2014-03-01

T-lymphocyte adhesion plays a critical role in both inflammatory and autoimmune responses. The small GTPase Rap1 is the key coordinator mediating T-cell adhesion to endothelial cells, antigen-presenting cells, and virus-infected cells. We describe a signaling pathway, downstream of the cytotoxic T-lymphocyte antigen 4 (CTLA-4) receptor, leading to Rap1-mediated adhesion. We identified a role for the Rap1 guanine nucleotide exchange factor C3G in the regulation of T-cell adhesion and showed that this factor is required for both T-cell receptor (TCR)-mediated and CTLA-4-mediated T-cell adhesion. Our data indicated that C3G translocates to the plasma membrane downstream of TCR signaling, where it regulates activation of Rap1. We also showed that CTLA-4 receptor signaling mediates tyrosine phosphorylation in the C3G protein, and that this is required for augmented activation of Rap1 and increased adhesion mediated by leukocyte function-associated antigen type 1 (LFA-1). Zap70 is required for C3G translocation to the plasma membrane, whereas the Src family member Hck facilitates C3G phosphorylation. These findings point to C3G and Hck as promising potential therapeutic targets for the treatment of T-cell-dependent autoimmune disorders.

Cell signaling molecules as drug targets in lung cancer: an overview.

PubMed

Mukherjee, Tapan K; Paul, Karan; Mukhopadhyay, Srirupa

2011-07-01

Lung being one of the vital and essential organs in the body, lung cancer is a major cause of mortality in the modern human society. Lung cancer can be broadly subdivided into nonsmall cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Although NSCLC is sometimes treated with surgery, the advanced and metastatic NSCLC and SCLC usually respond better to chemotherapy and radiation. The most important targets of these chemotherapeutic agents are various intracellular signaling molecules. The primary focus of this review article is to summarize the description of various cell signaling molecules involved in lung cancer development and their regulation by chemotherapeutic agents. Extensive research work in recent years has identified several cellular signaling molecules that may be intricately involved in the complexity of lung cancer. Some of these cell signaling molecules are epidermal growth factor receptors, vascular endothelial growth factor receptors, mammalian target of rapamycin, mitogen-activated protein kinase phosphatase-1, peroxisome proliferator-activated receptor-gamma, matrix metalloproteinases and receptor for advanced glycation end-products. The present review will strengthen our current knowledge regarding the efficacy of the above-mentioned cell signaling molecules as potential beneficial drug targets against lung cancer.

Protein C receptor stimulates multiple signaling pathways in breast cancer cells.

PubMed

Wang, Daisong; Liu, Chunye; Wang, Jingqiang; Jia, Yingying; Hu, Xin; Jiang, Hai; Shao, Zhi-Ming; Zeng, Yi Arial

2018-01-26

The protein C receptor (PROCR) has emerged as a stem cell marker in several normal tissues and has also been implicated in tumor progression. However, the functional role of PROCR and the signaling mechanisms downstream of PROCR remain poorly understood. Here, we dissected the PROCR signaling pathways in breast cancer cells. Combining protein array, knockdown, and overexpression methods, we found that PROCR concomitantly activates multiple pathways. We also noted that PROCR-dependent ERK and PI3k-Akt-mTOR signaling pathways proceed through Src kinase and transactivation of insulin-like growth factor 1 receptor (IGF-1R). These pathway activities led to the accumulation of c-Myc and cyclin D1. On the other hand, PROCR-dependent RhoA-ROCK-p38 signaling relied on coagulation factor II thrombin receptor (F2R). We confirmed these findings in primary cells isolated from triple-negative breast cancer-derived xenografts (PDX) that have high expression of PROCR. To the best our knowledge, this is the first comprehensive study of PROCR signaling in breast cancer cells, and its findings also shed light on the molecular mechanisms of PROCR in stem cells in normal tissue. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

Downstream-of-FGFR Is a Fibroblast Growth Factor-Specific Scaffolding Protein and Recruits Corkscrew upon Receptor Activation

PubMed Central

Petit, Valérie; Nussbaumer, Ute; Dossenbach, Caroline; Affolter, Markus

2004-01-01

Fibroblast growth factor (FGF) receptor (FGFR) signaling controls the migration of glial, mesodermal, and tracheal cells in Drosophila melanogaster. Little is known about the molecular events linking receptor activation to cytoskeletal rearrangements during cell migration. We have performed a functional characterization of Downstream-of-FGFR (Dof), a putative adapter protein that acts specifically in FGFR signal transduction in Drosophila. By combining reverse genetic, cell culture, and biochemical approaches, we demonstrate that Dof is a specific substrate for the two Drosophila FGFRs. After defining a minimal Dof rescue protein, we identify two regions important for Dof function in mesodermal and tracheal cell migration. The N-terminal 484 amino acids are strictly required for the interaction of Dof with the FGFRs. Upon receptor activation, tyrosine residue 515 becomes phosphorylated and recruits the phosphatase Corkscrew (Csw). Csw recruitment represents an essential step in FGF-induced cell migration and in the activation of the Ras/MAPK pathway. However, our results also indicate that the activation of Ras is not sufficient to activate the migration machinery in tracheal and mesodermal cells. Additional proteins binding either to the FGFRs, to Dof, or to Csw appear to be crucial for a chemotactic response. PMID:15082772

Downstream-of-FGFR is a fibroblast growth factor-specific scaffolding protein and recruits Corkscrew upon receptor activation.

PubMed

Petit, Valérie; Nussbaumer, Ute; Dossenbach, Caroline; Affolter, Markus

2004-05-01

Fibroblast growth factor (FGF) receptor (FGFR) signaling controls the migration of glial, mesodermal, and tracheal cells in Drosophila melanogaster. Little is known about the molecular events linking receptor activation to cytoskeletal rearrangements during cell migration. We have performed a functional characterization of Downstream-of-FGFR (Dof), a putative adapter protein that acts specifically in FGFR signal transduction in Drosophila. By combining reverse genetic, cell culture, and biochemical approaches, we demonstrate that Dof is a specific substrate for the two Drosophila FGFRs. After defining a minimal Dof rescue protein, we identify two regions important for Dof function in mesodermal and tracheal cell migration. The N-terminal 484 amino acids are strictly required for the interaction of Dof with the FGFRs. Upon receptor activation, tyrosine residue 515 becomes phosphorylated and recruits the phosphatase Corkscrew (Csw). Csw recruitment represents an essential step in FGF-induced cell migration and in the activation of the Ras/MAPK pathway. However, our results also indicate that the activation of Ras is not sufficient to activate the migration machinery in tracheal and mesodermal cells. Additional proteins binding either to the FGFRs, to Dof, or to Csw appear to be crucial for a chemotactic response.

Direct Melanoma Cell Contact Induces Stromal Cell Autocrine Prostaglandin E2-EP4 Receptor Signaling That Drives Tumor Growth, Angiogenesis, and Metastasis.

PubMed

Inada, Masaki; Takita, Morichika; Yokoyama, Satoshi; Watanabe, Kenta; Tominari, Tsukasa; Matsumoto, Chiho; Hirata, Michiko; Maru, Yoshiro; Maruyama, Takayuki; Sugimoto, Yukihiko; Narumiya, Shuh; Uematsu, Satoshi; Akira, Shizuo; Murphy, Gillian; Nagase, Hideaki; Miyaura, Chisato

2015-12-11

The stromal cells associated with tumors such as melanoma are significant determinants of tumor growth and metastasis. Using membrane-bound prostaglandin E synthase 1 (mPges1(-/-)) mice, we show that prostaglandin E2 (PGE2) production by host tissues is critical for B16 melanoma growth, angiogenesis, and metastasis to both bone and soft tissues. Concomitant studies in vitro showed that PGE2 production by fibroblasts is regulated by direct interaction with B16 cells. Autocrine activity of PGE2 further regulates the production of angiogenic factors by fibroblasts, which are key to the vascularization of both primary and metastatic tumor growth. Similarly, cell-cell interactions between B16 cells and host osteoblasts modulate mPGES-1 activity and PGE2 production by the osteoblasts. PGE2, in turn, acts to stimulate receptor activator of NF-κB ligand expression, leading to osteoclast differentiation and bone erosion. Using eicosanoid receptor antagonists, we show that PGE2 acts on osteoblasts and fibroblasts in the tumor microenvironment through the EP4 receptor. Metastatic tumor growth and vascularization in soft tissues was abrogated by an EP4 receptor antagonist. EP4-null Ptger4(-/-) mice do not support B16 melanoma growth. In vitro, an EP4 receptor antagonist modulated PGE2 effects on fibroblast production of angiogenic factors. Our data show that B16 melanoma cells directly influence host stromal cells to generate PGE2 signals governing neoangiogenesis and metastatic growth in bone via osteoclast erosive activity as well as angiogenesis in soft tissue tumors. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Direct Melanoma Cell Contact Induces Stromal Cell Autocrine Prostaglandin E2-EP4 Receptor Signaling That Drives Tumor Growth, Angiogenesis, and Metastasis*

PubMed Central

Inada, Masaki; Takita, Morichika; Yokoyama, Satoshi; Watanabe, Kenta; Tominari, Tsukasa; Matsumoto, Chiho; Hirata, Michiko; Maru, Yoshiro; Maruyama, Takayuki; Sugimoto, Yukihiko; Narumiya, Shuh; Uematsu, Satoshi; Akira, Shizuo; Murphy, Gillian; Nagase, Hideaki; Miyaura, Chisato

2015-01-01

The stromal cells associated with tumors such as melanoma are significant determinants of tumor growth and metastasis. Using membrane-bound prostaglandin E synthase 1 (mPges1−/−) mice, we show that prostaglandin E2 (PGE2) production by host tissues is critical for B16 melanoma growth, angiogenesis, and metastasis to both bone and soft tissues. Concomitant studies in vitro showed that PGE2 production by fibroblasts is regulated by direct interaction with B16 cells. Autocrine activity of PGE2 further regulates the production of angiogenic factors by fibroblasts, which are key to the vascularization of both primary and metastatic tumor growth. Similarly, cell-cell interactions between B16 cells and host osteoblasts modulate mPGES-1 activity and PGE2 production by the osteoblasts. PGE2, in turn, acts to stimulate receptor activator of NF-κB ligand expression, leading to osteoclast differentiation and bone erosion. Using eicosanoid receptor antagonists, we show that PGE2 acts on osteoblasts and fibroblasts in the tumor microenvironment through the EP4 receptor. Metastatic tumor growth and vascularization in soft tissues was abrogated by an EP4 receptor antagonist. EP4-null Ptger4−/− mice do not support B16 melanoma growth. In vitro, an EP4 receptor antagonist modulated PGE2 effects on fibroblast production of angiogenic factors. Our data show that B16 melanoma cells directly influence host stromal cells to generate PGE2 signals governing neoangiogenesis and metastatic growth in bone via osteoclast erosive activity as well as angiogenesis in soft tissue tumors. PMID:26475855

The C-type Lectin Langerin Functions as a Receptor for Attachment and Infectious Entry of Influenza A Virus.

PubMed

Ng, Wy Ching; Londrigan, Sarah L; Nasr, Najla; Cunningham, Anthony L; Turville, Stuart; Brooks, Andrew G; Reading, Patrick C

2016-01-01

It is well established that influenza A virus (IAV) attachment to and infection of epithelial cells is dependent on sialic acid (SIA) at the cell surface, although the specific receptors that mediate IAV entry have not been defined and multiple receptors may exist. Lec2 Chinese hamster ovary (CHO) cells are SIA deficient and resistant to IAV infection. Here we demonstrate that the expression of the C-type lectin receptor langerin in Lec2 cells (Lec2-Lg) rendered them permissive to IAV infection, as measured by replication of the viral genome, transcription of viral mRNA, and synthesis of viral proteins. Unlike SIA-dependent infection of parental CHO cells, IAV attachment and infection of Lec2-Lg cells was mediated via lectin-mediated recognition of mannose-rich glycans expressed by the viral hemagglutinin glycoprotein. Lec2 cells expressing endocytosis-defective langerin bound IAV efficiently but remained resistant to IAV infection, confirming that internalization via langerin was essential for infectious entry. Langerin-mediated infection of Lec2-Lg cells was pH and dynamin dependent, occurred via clathrin- and caveolin-mediated endocytic pathways, and utilized early (Rab5(+)) but not late (Rab7(+)) endosomes. This study is the first to demonstrate that langerin represents an authentic receptor that binds and internalizes IAV to facilitate infection. Moreover, it describes a unique experimental system to probe specific pathways and compartments involved in infectious entry following recognition of IAV by a single cell surface receptor. On the surface of host cells, sialic acid (SIA) functions as the major attachment factor for influenza A viruses (IAV). However, few studies have identified specific transmembrane receptors that bind and internalize IAV to facilitate infection. Here we identify human langerin as a transmembrane glycoprotein that can act as an attachment factor and a bone fide endocytic receptor for IAV infection. Expression of langerin by an SIA-deficient cell line resistant to IAV rendered cells permissive to infection. As langerin represented the sole receptor for IAV infection in this system, we have defined the pathways and compartments involved in infectious entry of IAV into cells following recognition by langerin. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Toll-like Receptors and B-cell Receptors Synergize to Induce Immunoglobulin Class Switch DNA Recombination: Relevance to Microbial Antibody Responses

PubMed Central

Pone, Egest J.; Zan, Hong; Zhang, Jinsong; Al-Qahtani, Ahmed; Xu, Zhenming; Casali, Paolo

2011-01-01

Differentiation of naïve B cells, including immunoglobulin (Ig) class switch DNA recombination (CSR), is critical for the immune response and depends on the extensive integration of signals from the B cell receptor (BCR), tumor necrosis factor (TNF) receptor family members, Toll-like receptors (TLRs) and cytokine receptors. TLRs and BCR synergize to induce CSR in T cell-dependent and T cell-independent antibody responses to microbial pathogens. BCR triggering together with simultaneous endosomal TLR engagement leads to enhanced B cell differentiation and antibody responses. The requirement of both BCR and TLR engagement would ensure appropriate antigen-specific activation in an infection. Co-stimulation of TLRs and BCR likely plays a significant role in anti-microbial antibody responses to contain pathogen loads until the T cell-dependent antibody responses peak. Furthermore, the temporal sequence of different signals is also critical for optimal B cell responses, as exemplified by the activation of B cells by initial TLR engagement, leading to the upregulation of co-stimulatory CD80 and MHC-II receptors, which, in turn, result in more efficient interactions with T cells, thereby enhancing the germinal center (GC) reaction and antibody affinity maturation. Overall, BCR and TLR stimulation and the integration with signals from the pathogen or immune cells and their products, determine the ensuing B cell antibody response. PMID:20370617

The Wnt receptor Ryk controls specification of GABAergic neurons versus oligodendrocytes during telencephalon development

PubMed Central

Zhong, Jingyang; Kim, Hyoung-Tai; Lyu, Jungmook; Yoshikawa, Kazuaki; Nakafuku, Masato; Lu, Wange

2011-01-01

GABAergic neurons and oligodendrocytes originate from progenitors within the ventral telencephalon. However, the molecular mechanisms that control neuron-glial cell-fate segregation, especially how extrinsic factors regulate cell-fate changes, are poorly understood. We have discovered that the Wnt receptor Ryk promotes GABAergic neuron production while repressing oligodendrocyte formation in the ventral telencephalon. We demonstrate that Ryk controls the cell-fate switch by negatively regulating expression of the intrinsic oligodendrogenic factor Olig2 while inducing expression of the interneuron fate determinant Dlx2. In addition, we demonstrate that Ryk is required for GABAergic neuron induction and oligodendrogenesis inhibition caused by Wnt3a stimulation. Furthermore, we showed that the cleaved intracellular domain of Ryk is sufficient to regulate the cell-fate switch by regulating the expression of intrinsic cell-fate determinants. These results identify Ryk as a multi-functional receptor that is able to transduce extrinsic cues into progenitor cells, promote GABAergic neuron formation, and inhibit oligodendrogenesis during ventral embryonic brain development. PMID:21205786

Epidermal growth factor receptor subunit locations determined in hydrated cells with environmental scanning electron microscopy.

PubMed

Peckys, Diana B; Baudoin, Jean-Pierre; Eder, Magdalena; Werner, Ulf; de Jonge, Niels

2013-01-01

Imaging single epidermal growth factor receptors (EGFR) in intact cells is presently limited by the available microscopy methods. Environmental scanning electron microscopy (ESEM) of whole cells in hydrated state in combination with specific labeling with gold nanoparticles was used to localize activated EGFRs in the plasma membranes of COS7 and A549 cells. The use of a scanning transmission electron microscopy (STEM) detector yielded a spatial resolution of 3 nm, sufficient to identify the locations of individual EGFR dimer subunits. The sizes and distribution of dimers and higher order clusters of EGFRs were determined. The distance between labels bound to dimers amounted to 19 nm, consistent with a molecular model. A fraction of the EGFRs was found in higher order clusters with sizes ranging from 32-56 nm. ESEM can be used for quantitative whole cell screening studies of membrane receptors, and for the study of nanoparticle-cell interactions in general.

Epidermal growth factor receptor subunit locations determined in hydrated cells with environmental scanning electron microscopy

PubMed Central

Peckys, Diana B.; Baudoin, Jean-Pierre; Eder, Magdalena; Werner, Ulf; de Jonge, Niels

2013-01-01

Imaging single epidermal growth factor receptors (EGFR) in intact cells is presently limited by the available microscopy methods. Environmental scanning electron microscopy (ESEM) of whole cells in hydrated state in combination with specific labeling with gold nanoparticles was used to localize activated EGFRs in the plasma membranes of COS7 and A549 cells. The use of a scanning transmission electron microscopy (STEM) detector yielded a spatial resolution of 3 nm, sufficient to identify the locations of individual EGFR dimer subunits. The sizes and distribution of dimers and higher order clusters of EGFRs were determined. The distance between labels bound to dimers amounted to 19 nm, consistent with a molecular model. A fraction of the EGFRs was found in higher order clusters with sizes ranging from 32–56 nm. ESEM can be used for quantitative whole cell screening studies of membrane receptors, and for the study of nanoparticle-cell interactions in general. PMID:24022088

The mapping of yeast's G-protein coupled receptor with an atomic force microscope

NASA Astrophysics Data System (ADS)

Takenaka, Musashi; Miyachi, Yusuke; Ishii, Jun; Ogino, Chiaki; Kondo, Akihiko

2015-03-01

An atomic force microscope (AFM) can measure the adhesion force between a sample and a cantilever while simultaneously applying a rupture force during the imaging of a sample. An AFM should be useful in targeting specific proteins on a cell surface. The present study proposes the use of an AFM to measure the adhesion force between targeting receptors and their ligands, and to map the targeting receptors. In this study, Ste2p, one of the G protein-coupled receptors (GPCRs), was chosen as the target receptor. The specific force between Ste2p on a yeast cell surface and a cantilever modified with its ligand, α-factor, was measured and found to be approximately 250 pN. In addition, through continuous measuring of the cell surface, a mapping of the receptors on the cell surface could be performed, which indicated the differences in the Ste2p expression levels. Therefore, the proposed AFM system is accurate for cell diagnosis.

Activated HGF-c-Met Axis in Head and Neck Cancer

PubMed Central

Arnold, Levi; Enders, Jonathan; Thomas, Sufi Mary

2017-01-01

Head and neck squamous cell carcinoma (HNSCC) is a highly morbid disease. Recent developments including Food and Drug Administration (FDA) approved molecular targeted agent’s pembrolizumab and cetuximab show promise but did not improve the five-year survival which is currently less than 40%. The hepatocyte growth factor receptor; also known as mesenchymal–epithelial transition factor (c-Met) and its ligand hepatocyte growth factor (HGF) are overexpressed in head and neck squamous cell carcinoma (HNSCC); and regulates tumor progression and response to therapy. The c-Met pathway has been shown to regulate many cellular processes such as cell proliferation, invasion, and angiogenesis. The c-Met pathway is involved in cross-talk, activation, and perpetuation of other signaling pathways, curbing the cogency of a blockade molecule on a single pathway. The receptor and its ligand act on several downstream effectors including phospholipase C gamma (PLCγ), cellular Src kinase (c-Src), phosphotidylinsitol-3-OH kinase (PI3K) alpha serine/threonine-protein kinase (Akt), mitogen activate protein kinase (MAPK), and wingless-related integration site (Wnt) pathways. They are also known to cross-talk with other receptors; namely epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor (VEGFR) and specifically contribute to treatment resistance. Clinical trials targeting the c-Met axis in HNSCC have been undertaken because of significant preclinical work demonstrating a relationship between HGF/c-Met signaling and cancer cell survival. Here we focus on HGF/c-Met impact on cellular signaling in HNSCC to potentiate tumor growth and disrupt therapeutic efficacy. Herein we summarize the current understanding of HGF/c-Met signaling and its effects on HNSCC. The intertwining of c-Met signaling with other signaling pathways provides opportunities for more robust and specific therapies, leading to better clinical outcomes. PMID:29231907

Activation-Induced Killer Cell Immunoglobulin-like Receptor 3DL2 Binding to HLA-B27 Licenses Pathogenic T Cell Differentiation in Spondyloarthritis.

PubMed

Ridley, Anna; Hatano, Hiroko; Wong-Baeza, Isabel; Shaw, Jacqueline; Matthews, Katherine K; Al-Mossawi, Hussein; Ladell, Kristin; Price, David A; Bowness, Paul; Kollnberger, Simon

2016-04-01

In the spondyloarthritides (SpA), increased numbers of CD4+ T cells express killer cell immunoglobulin-like receptor 3DL2 (KIR-3DL2). The aim of this study was to determine the factors that induce KIR-3DL2 expression, and to characterize the relationship between HLA-B27 and the phenotype and function of KIR-3DL2-expressing CD4+ T cells in SpA. In total, 34 B27+ patients with SpA, 28 age- and sex-matched healthy controls (20 B27- and 8 B27+), and 9 patients with rheumatoid arthritis were studied. KIR-3DL2 expression and other phenotypic characteristics of peripheral blood and synovial fluid CD4+ T cells were studied by flow cytometry, quantitative polymerase chain reaction, and Western blotting. T cell receptor clonality was determined by template-switch anchored reverse transcription-polymerase chain reaction and sequencing analysis. Cytokines were measured by enzyme-linked immunosorbent assay. Cellular activation induced KIR-3DL2 expression on both naive and effector CD4+ T cells. KIR-3DL2 binding to B27+ cells promoted expression of KIR-3DL2, the Th17-specific transcription factor retinoic acid receptor-related orphan nuclear receptor γt, and the antiapoptotic factor B cell lymphoma 2. KIR-3DL2+CD4+ T cells in patients with ankylosing spondylitis were oligoclonal and enriched for markers of T cell activation and for the gut homing receptor CCR9. In the presence of B27+ antigen-presenting cells, KIR-3DL2+CD4+ T cells produced less interleukin-2 (IL-2) but more IL-17. This effect was blocked by HC10, an antibody that inhibits the binding of KIR-3DL2 to B27 heavy chains. KIR-3DL2 binding to HLA-B27 licenses Th17 cell differentiation in SpA. These findings raise the therapeutic potential of targeting HLA-B27-KIR-3DL2 interactions for the treatment of B27+ patients with SpA. © 2016 The Authors. Arthritis & Rheumatology published by Wiley Periodicals, Inc. on behalf of the American College of Rheumatology.

Resveratrol inhibits proteinase-activated receptor-2-induced release of soluble vascular endothelial growth factor receptor-1 from human endothelial cells

PubMed Central

Al-Ani, Bahjat

2013-01-01

We recently reported that (i) activation of the proinflammatory receptor, proteinase-activated receptor-2 (PAR-2) caused the release of an important biomarker in preeclampsia, soluble vascular endothelial growth factor receptor-1 (sVEGFR-1, also known as sFlt-1) from human umbilical vein endothelial cells (HUVECs), and (ii) that the anti-oxidant and anti-inflammatory agent, resveratrol, is capable of inhibiting the proinflammatory cytokine-induced sVEGFR-1 release from human placenta. Based on these findings and because PAR-2 is upregulated by proinflammatory cytokines, we sought to determine whether resveratrol can inhibit PAR-2-induced sVEGFR-1 release. PAR-2 expressing cells, HUVECs and human embryonic kidney cells (HEK-293) transfected with a human VEGFR-1 promoter-luciferase reporter construct were incubated with PAR-2-activating peptide and/or resveratrol. Cell supernatants were assayed for sVEGFR-1 by enzyme-linked immunosorbent assay (ELISA), and VEGFR-1 promoter-luciferase assay was performed on the harvested cell lysates. Preincubation of HEK-293 cells with resveratrol significantly inhibited PAR-2-induced VEGFR-1 promoter activity without affecting cell viability as assessed by MTT assay. The addition of resveratrol also blocked PAR-2-mediated sVEGFR-1 release from HUVECs. The present study demonstrates that resveratrol suppressed both VEGFR-1 promoter activity and sVEGFR-1 protein release induced by PAR-2 activation, which further endorses our recent findings of a potential therapeutic role for resveratrol in preeclampsia. PMID:26933402

Ubiquitination of basal VEGFR2 regulates signal transduction and endothelial function

PubMed Central

Smith, Gina A.; Fearnley, Gareth W.; Abdul-Zani, Izma; Wheatcroft, Stephen B.; Tomlinson, Darren C.; Harrison, Michael A.

2017-01-01

ABSTRACT Cell surface receptors can undergo recycling or proteolysis but the cellular decision-making events that sort between these pathways remain poorly defined. Vascular endothelial growth factor A (VEGF-A) and vascular endothelial growth factor receptor 2 (VEGFR2) regulate signal transduction and angiogenesis, but how signaling and proteolysis is regulated is not well understood. Here, we provide evidence that a pathway requiring the E1 ubiquitin-activating enzyme UBA1 controls basal VEGFR2 levels, hence metering plasma membrane receptor availability for the VEGF-A-regulated endothelial cell response. VEGFR2 undergoes VEGF-A-independent constitutive degradation via a UBA1-dependent ubiquitin-linked pathway. Depletion of UBA1 increased VEGFR2 recycling from endosome-to-plasma membrane and decreased proteolysis. Increased membrane receptor availability after UBA1 depletion elevated VEGF-A-stimulated activation of key signaling enzymes such as PLCγ1 and ERK1/2. Although UBA1 depletion caused an overall decrease in endothelial cell proliferation, surviving cells showed greater VEGF-A-stimulated responses such as cell migration and tubulogenesis. Our study now suggests that a ubiquitin-linked pathway regulates the balance between receptor recycling and degradation which in turn impacts on the intensity and duration of VEGF-A-stimulated signal transduction and the endothelial response. PMID:28798148

Involvement of lipid rafts in adhesion-induced activation of Met and EGFR.

PubMed

Lu, Ying-Che; Chen, Hong-Chen

2011-10-27

Cell adhesion has been shown to induce activation of certain growth factor receptors in a ligand-independent manner. However, the mechanism for such activation remains obscure. Human epidermal carcinoma A431 cells were used as a model to examine the mechanism for adhesion-induced activation of hepatocyte growth factor receptor Met and epidermal growth factor receptor (EGFR). The cells were suspended and replated on culture dishes under various conditions. The phosphorylation of Met at Y1234/1235 and EGFR at Y1173 were used as indicators for their activation. The distribution of the receptors and lipid rafts on the plasma membrane were visualized by confocal fluorescent microscopy and total internal reflection microscopy. We demonstrate that Met and EGFR are constitutively activated in A431 cells, which confers proliferative and invasive potentials to the cells. The ligand-independent activation of Met and EGFR in A431 cells relies on cell adhesion to a substratum, but is independent of cell spreading, extracellular matrix proteins, and substratum stiffness. This adhesion-induced activation of Met and EGFR cannot be attributed to Src activation, production of reactive oxygen species, and the integrity of the cytoskeleton. In addition, we demonstrate that Met and EGFR are independently activated upon cell adhesion. However, partial depletion of Met and EGFR prevents their activation upon cell adhesion, suggesting that overexpression of the receptors is a prerequisite for their self-activation upon cell adhesion. Although Met and EGFR are largely distributed in 0.04% Triton-insoluble fractions (i.e. raft fraction), their activated forms are detected mainly in 0.04% Triton-soluble fractions (i.e. non-raft fraction). Upon cell adhesion, lipid rafts are accumulated at the cell surface close to the cell-substratum interface, while Met and EGFR are mostly excluded from the membrane enriched by lipid rafts. Our results suggest for the first time that cell adhesion to a substratum may induce a polarized distribution of lipid rafts to the cell-substratum interface, which may allow Met and EGFR to be released from lipid rafts, thus leading to their activation in a ligand-independent manner.

Studying Nuclear Receptor Complexes in the Cellular Environment.

PubMed

Schaufele, Fred

2016-01-01

The ligand-regulated structure and biochemistry of nuclear receptor complexes are commonly determined by in vitro studies of isolated receptors, cofactors, and their fragments. However, in the living cell, the complexes that form are governed not just by the relative affinities of isolated cofactors for the receptor but also by the cell-specific sequestration or concentration of subsets of competing or cooperating cofactors, receptors, and other effectors into distinct subcellular domains and/or their temporary diversion into other cellular activities. Most methods developed to understand nuclear receptor function in the cellular environment involve the direct tagging of the nuclear receptor or its cofactors with fluorescent proteins (FPs) and the tracking of those FP-tagged factors by fluorescence microscopy. One of those approaches, Förster resonance energy transfer (FRET) microscopy, quantifies the transfer of energy from a higher energy "donor" FP to a lower energy "acceptor" FP attached to a single protein or to interacting proteins. The amount of FRET is influenced by the ligand-induced changes in the proximities and orientations of the FPs within the tagged nuclear receptor complexes, which is an indicator of the structure of the complexes, and by the kinetics of the interaction between FP-tagged factors. Here, we provide a guide for parsing information about the structure and biochemistry of nuclear receptor complexes from FRET measurements in living cells.

Eukaryotic Translation Initiation Factor 4E Is a Feed-Forward Translational Coactivator of Transforming Growth Factor β Early Protransforming Events in Breast Epithelial Cells

PubMed Central

Decarlo, Lindsey; Mestel, Celine; Barcellos-Hoff, Mary-Helen

2015-01-01

Eukaryotic translation initiation factor 4E (eIF4E) is overexpressed early in breast cancers in association with disease progression and reduced survival. Much remains to be understood regarding the role of eIF4E in human cancer. We determined, using immortalized human breast epithelial cells, that elevated expression of eIF4E translationally activates the transforming growth factor β (TGF-β) pathway, promoting cell invasion, a loss of cell polarity, increased cell survival, and other hallmarks of early neoplasia. Overexpression of eIF4E is shown to facilitate the selective translation of integrin β1 mRNA, which drives the translationally controlled assembly of a TGF-β receptor signaling complex containing α3β1 integrins, β-catenin, TGF-β receptor I, E-cadherin, and phosphorylated Smad2/3. This receptor complex acutely sensitizes nonmalignant breast epithelial cells to activation by typically substimulatory levels of activated TGF-β. TGF-β can promote cellular differentiation or invasion and transformation. As a translational coactivator of TGF-β, eIF4E confers selective mRNA translation, reprogramming nonmalignant cells to an invasive phenotype by reducing the set point for stimulation by activated TGF-β. Overexpression of eIF4E may be a proinvasive facilitator of TGF-β activity. PMID:25986608

Differential expression of FGF receptors and of myogenic regulatory factors in primary cultures of satellite cells originating from fast (EDL) and slow (Soleus) twitch rat muscles.

PubMed

Martelly, I; Soulet, L; Bonnavaud, S; Cebrian, J; Gautron, J; Barritault, D

2000-11-01

In the rat, the fast and slow twitch muscles respectively Extensor digitorum longus (EDL) and Soleus present differential characteristics during regeneration. This suggests that their satellite cells responsible for muscle growth and repair represent distinct cellular populations. We have previously shown that satellite cells dissociated from Soleus and grown in vitro proliferate more readily than those isolated from EDL muscle. Fibroblast growth factors (FGFs) are known as regulators of myoblast proliferation and several studies have revealed a relationship between the response of myoblasts to FGF and the expression of myogenic regulatory factors (MRF) of the MyoD family by myoblasts. Therefore, we presently examined the possibility that the satellite cells isolated from EDL and Soleus muscles differ in the expression of FGF receptors (FGF-R) and of MRF expression. FGF-R1 and -R4 were strongly expressed in proliferating cultures whereas FGF-R2 and R3 were not detected in these cultures. In differentiating cultures, only -R1 was present in EDL satellite cells while FGF-R4 was also still expressed in Soleus cells. Interestingly, the unconventional receptor for FGF called cystein rich FGF receptor (CFR), of yet unknown function, was mainly detected in EDL satellite cell cultures. Soleus and EDL satellite cell cultures also differed in the expression MRFs. These results are consistent with the notion that satellite cells from fast and slow twitch muscles belong to different types of myogenic cells and suggest that satellite cells might play distinct roles in the formation and diversification of fast and slow fibres.

Intracrine prostaglandin E2 pro-tumoral actions in prostate epithelial cells originate from non-canonical pathways.

PubMed

Madrigal-Martínez, Antonio; Fernández-Martínez, Ana B; Lucio Cazaña, Francisco J

2018-04-01

Prostaglandin E 2 (PGE 2 ) increases cell proliferation and stimulates migratory and angiogenic abilities in prostate cancer cells. However, the effects of PGE 2 on non-transformed prostate epithelial cells are unknown, despite the fact that PGE 2 overproduction has been found in benign hyperplastic prostates. In the present work we studied the effects of PGE 2 in immortalized, non-malignant prostate epithelial RWPE-1 cells and found that PGE 2 increased cell proliferation, cell migration, and production of vascular endothelial growth factor-A, and activated in vitro angiogenesis. These actions involved a non-canonic intracrine mechanism in which the actual effector was intracellular PGE 2 (iPGE 2 ) instead of extracellular PGE 2 : inhibition of the prostaglandin uptake transporter (PGT) or antagonism of EP receptors prevented the effects of PGE 2 , which indicated that PGE 2 activity depended on its carrier-mediated translocation from the outside to the inside of cells and that EP receptors located intracellularly (iEP) mediated the effects of PGE 2 . iPGE 2 acted through transactivation of epidermal growth factor-receptor (EGFR) by iEP, leading to increased expression and activity of hypoxia-inducible factor-1α (HIF-1α). Interestingly, iPGE 2 also mediates the effects of PGE 2 on prostate cancer PC3 cells through the axis iPGE 2 -iEP receptors-EGFR-HIF-1α. Thus, this axis might be responsible for the growth-stimulating effects of PGE 2 on prostate epithelial cells, thereby contributing to prostate proliferative diseases associated with chronic inflammation. Since this PGT-dependent non-canonic intracrine mechanism of PGE 2 action operates in both benign and malignant prostate epithelial cells, PGT inhibitors should be tested as a novel therapeutic modality to treat prostate proliferative disease. © 2017 Wiley Periodicals, Inc.

Insulin-Like Growth Factors Are Expressed in the Taste System, but Do Not Maintain Adult Taste Buds.

PubMed

Biggs, Bradley T; Tang, Tao; Krimm, Robin F

2016-01-01

Growth factors regulate cell growth and differentiation in many tissues. In the taste system, as yet unknown growth factors are produced by neurons to maintain taste buds. A number of growth factor receptors are expressed at greater levels in taste buds than in the surrounding epithelium and may be receptors for candidate factors involved in taste bud maintenance. We determined that the ligands of eight of these receptors were expressed in the E14.5 geniculate ganglion and that four of these ligands were expressed in the adult geniculate ganglion. Of these, the insulin-like growth factors (IGF1, IGF2) were expressed in the ganglion and their receptor, insulin-like growth factor receptor 1 (IGF1R), were expressed at the highest levels in taste buds. To determine whether IGF1R regulates taste bud number or structure, we conditionally eliminated IGF1R from the lingual epithelium of mice using the keratin 14 (K14) promoter (K14-Cre::Igf1rlox/lox). While K14-Cre::Igf1rlox/lox mice had significantly fewer taste buds at P30 compared with control mice (Igf1rlox/lox), this difference was not observed by P80. IGF1R removal did not affect taste bud size or cell number, and the number of phospholipase C β2- (PLCβ2) and carbonic anhydrase 4- (Car4) positive taste receptor cells did not differ between genotypes. Taste buds at the back of the tongue fungiform taste field were larger and contained more cells than those at the tongue tip, and these differences were diminished in K14-Cre::Igf1rlox/lox mice. The epithelium was thicker at the back versus the tip of the tongue, and this difference was also attenuated in K14-Cre::Igf1rlox/lox mice. We conclude that, although IGFs are expressed at high levels in the taste system, they likely play little or no role in maintaining adult taste bud structure. IGFs have a potential role in establishing the initial number of taste buds, and there may be limits on epithelial thickness in the absence of IGF1R signaling.

Macrophage interleukin-6 and tumour necrosis factor-α are induced by coronavirus fixation to Toll-like receptor 2/heparan sulphate receptors but not carcinoembryonic cell adhesion antigen 1a

PubMed Central

Jacques, Alexandre; Bleau, Christian; Turbide, Claire; Beauchemin, Nicole; Lamontagne, Lucie

2009-01-01

A rapid antiviral immune response may be related to viral interaction with the host cell leading to activation of macrophages via pattern recognition receptors (PPRs) or specific viral receptors. Carcinoembryonic cell adhesion antigen 1a (CEACAM1a) is the specific receptor for the mouse hepatitis virus (MHV), a coronavirus known to induce acute viral hepatitis in mice. The objective of this study was to understand the mechanisms responsible for the secretion of high-pathogenic MHV3-induced inflammatory cytokines. We report that the induction of the pro-inflammatory cytokines interleukin (IL)-6 and tumour necrosis factor (TNF)-α in peritoneal macrophages does not depend on CEACAM1a, as demonstrated in cells isolated from Ceacam1a−/− mice. The induction of IL-6 and TNF-α production was related rather to the fixation of the spike (S) protein of MHV3 on Toll-like receptor 2 (TLR2) in regions enriched in heparan sulphate and did not rely on viral replication, as demonstrated with denatured S protein and UV-inactivated virus. High levels of IL-6 and TNF-α were produced in livers from infected C57BL/6 mice but not in livers from Tlr2−/− mice. The histopathological observations were correlated with the levels of those inflammatory cytokines. Depending on mouse strain, the viral fixation to heparan sulfate/TLR2 stimulated differently the p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB in the induction of IL-6 and TNF-α. These results suggest that TLR2 and heparan sulphate receptors can act as new viral PPRs involved in inflammatory responses. PMID:19740307

Cell-based capacitance sensor for analysis of EGFR expression on cell membrane

NASA Astrophysics Data System (ADS)

Shin, Dong-Myeong; Shin, Yong-Cheol; Ha, Ji Hye; Lee, Jong-Ho; Han, Dong-Wook; Kim, Jong-Man; Kim, Hyung Kook; Hwang, Yoon-Hwae

2013-02-01

Cancer cells have many kinds of cancer biomarkers. Among them, the epidermal growth factor (EGF) receptors can show a possibility for a cancer marker because the over-expression of EGF receptor is related with fibrous, colorectal, cervical and gastric tumorigenesis. We fabricated the capacitance sensor with a gap area of 50 μm × 200 μm by using photolithography and lift-off method. Using the capacitance sensor, we investigated the time dependent capacitance changes of different kinds of fibrous cells, such as HT1080 fibrosarcoma, L-929 fibroblast cell line and nHDF dermal fibroblast primary cell. We found that when we put the EGF, the capacitance decreased due to the immobilization of EGF to EGF receptor on the cell membrane. The quantitative determination of EGF receptor level for various fibrous cells was carried out and the results showed good correlation with conventional method. Based on our results, we suggest that the capacitance sensor can measure the expression level of the EGF receptor on cell membrane and be a good candidate as a cancer diagnosis.

17β-estradiol-induced regulation of the novel 5-HT1A-related transcription factors NUDR and Freud-1 in SH SY5Y cells.

PubMed

Adeosun, Samuel O; Albert, Paul R; Austin, Mark C; Iyo, Abiye H

2012-05-01

Nuclear deformed epidermal autoregulatory factor-1 (NUDR/Deaf-1) and five prime repressor element under dual repression (Freud-1) are novel transcriptional regulators of the 5-HT(1A) receptor, a receptor that has been implicated in the pathophysiology of various psychiatric illnesses. The antidepressant effect of 17β-Estradiol (17βE(2)) is purported to involve the downregulation of this receptor. We investigated the possible role of NUDR and Freud-1 in 17βE(2)-induced downregulation of the 5-HT(1A) receptor in the neuroblastoma cell line SH SY5Y. Cells were treated with 10 nM of 17βE(2) for 3 or 48 h, followed by a 24-h withdrawal period. Proteins were isolated and analyzed by western blotting. 17βE(2) treatment increased NUDR immunoreactivity while Freud-1 and the 5-HT(1A) receptor showed significant decreases. Upon withdrawal of 17βE(2), protein expression returned to control levels, except for NUDR, which remained significantly elevated in the 3-h treatment. Taken together, these data support a non-genomic downregulation of 5-HT(1A) receptor protein by 17βE(2), which does not involve NUDR and Freud-1. Rather, changes in both transcription factors seem to be compensatory/homeostatic responses to changes in 5-HT(1A) receptor induced by 17βE(2). These observations further highlight the importance of NUDR and Freud-1 in regulating 5-HT(1A) receptor expression.

Role of gonadotropin-releasing hormone (GnRH) in ovarian cancer

PubMed Central

Gründker, Carsten; Emons, Günter

2003-01-01

The expression of GnRH (GnRH-I, LHRH) and its receptor as a part of an autocrine regulatory system of cell proliferation has been demonstrated in a number of human malignant tumors, including cancers of the ovary. The proliferation of human ovarian cancer cell lines is time- and dose-dependently reduced by GnRH and its superagonistic analogs. The classical GnRH receptor signal-transduction mechanisms, known to operate in the pituitary, are not involved in the mediation of antiproliferative effects of GnRH analogs in these cancer cells. The GnRH receptor rather interacts with the mitogenic signal transduction of growth-factor receptors and related oncogene products associated with tyrosine kinase activity via activation of a phosphotyrosine phosphatase resulting in downregulation of cancer cell proliferation. In addition GnRH activates nucleus factor κB (NFκB) and protects the cancer cells from apoptosis. Furthermore GnRH induces activation of the c-Jun N-terminal kinase/activator protein-1 (JNK/AP-1) pathway independent of the known AP-1 activators, protein kinase (PKC) or mitogen activated protein kinase (MAPK/ERK). Recently it was shown that human ovarian cancer cells express a putative second GnRH receptor specific for GnRH type II (GnRH-II). The proliferation of these cells is dose- and time-dependently reduced by GnRH-II in a greater extent than by GnRH-I (GnRH, LHRH) superagonists. In previous studies we have demonstrated that in ovarian cancer cell lines except for the EFO-27 cell line GnRH-I antagonist Cetrorelix has comparable antiproliferative effects as GnRH-I agonists indicating that the dichotomy of GnRH-I agonists and antagonists might not apply to the GnRH-I system in cancer cells. After GnRH-I receptor knock down the antiproliferative effects of GnRH-I agonist Triptorelin were abrogated while the effects of GnRH-I antagonist Cetrorelix and GnRH-II were still existing. In addition, in the ovarian cancer cell line EFO-27 GnRH-I receptor but not putative GnRH-II receptor expression was found. These data suggest that in ovarian cancer cells the antiproliferative effects of GnRH-I antagonist Cetrorelix and GnRH-II are not mediated through the GnRH-I receptor. PMID:14594454

Regulatory T cells protect mice against coxsackievirus-induced myocarditis through the transforming growth factor beta-coxsackie-adenovirus receptor pathway.

PubMed

Shi, Yu; Fukuoka, Masahiro; Li, Guohua; Liu, Youan; Chen, Manyin; Konviser, Michael; Chen, Xin; Opavsky, Mary Anne; Liu, Peter P

2010-06-22

Coxsackievirus B3 infection is an excellent model of human myocarditis and dilated cardiomyopathy. Cardiac injury is caused either by a direct cytopathic effect of the virus or through immune-mediated mechanisms. Regulatory T cells (Tregs) play an important role in the negative modulation of host immune responses and set the threshold of autoimmune activation. This study was designed to test the protective effects of Tregs and to determine the underlying mechanisms. Carboxyfluorescein diacetate succinimidyl ester-labeled Tregs or naïve CD4(+) T cells were injected intravenously once every 2 weeks 3 times into mice. The mice were then challenged with intraperitoneal coxsackievirus B3 immediately after the last cell transfer. Transfer of Tregs showed higher survival rates than transfer of CD4(+) T cells (P=0.0136) but not compared with the PBS injection group (P=0.0589). Interestingly, Tregs also significantly decreased virus titers and inflammatory scores in the heart. Transforming growth factor-beta and phosphorylated AKT were upregulated in Tregs-transferred mice and coxsackie-adenovirus receptor expression was decreased in the heart compared with control groups. Transforming growth factor-beta decreased coxsackie-adenovirus receptor expression and inhibited coxsackievirus B3 infection in HL-1 cells and neonatal cardiac myocytes. Splenocytes collected from Treg-, CD4(+) T-cell-, and PBS-treated mice proliferated equally when stimulated with heat-inactivated virus, whereas in the Treg group, the proliferation rate was reduced significantly when stimulated with noninfected heart tissue homogenate. Adoptive transfer of Tregs protected mice from coxsackievirus B3-induced myocarditis through the transforming growth factor beta-coxsackie-adenovirus receptor pathway and thus suppresses the immune response to cardiac tissue, maintaining the antiviral immune response.

TAM receptors support neural stem cell survival, proliferation and neuronal differentiation.

PubMed

Ji, Rui; Meng, Lingbin; Jiang, Xin; Cvm, Naresh Kumar; Ding, Jixiang; Li, Qiutang; Lu, Qingxian

2014-01-01

Tyro3, Axl and Mertk (TAM) receptor tyrosine kinases play multiple functional roles by either providing intrinsic trophic support for cell growth or regulating the expression of target genes that are important in the homeostatic regulation of immune responses. TAM receptors have been shown to regulate adult hippocampal neurogenesis by negatively regulation of glial cell activation in central nervous system (CNS). In the present study, we further demonstrated that all three TAM receptors were expressed by cultured primary neural stem cells (NSCs) and played a direct growth trophic role in NSCs proliferation, neuronal differentiation and survival. The cultured primary NSCs lacking TAM receptors exhibited slower growth, reduced proliferation and increased apoptosis as shown by decreased BrdU incorporation and increased TUNEL labeling, than those from the WT NSCs. In addition, the neuronal differentiation and maturation of the mutant NSCs were impeded, as characterized by less neuronal differentiation (β-tubulin III+) and neurite outgrowth than their WT counterparts. To elucidate the underlying mechanism that the TAM receptors play on the differentiating NSCs, we examined the expression profile of neurotrophins and their receptors by real-time qPCR on the total RNAs from hippocampus and primary NSCs; and found that the TKO NSC showed a significant reduction in the expression of both nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), but accompanied by compensational increases in the expression of the TrkA, TrkB, TrkC and p75 receptors. These results suggest that TAM receptors support NSCs survival, proliferation and differentiation by regulating expression of neurotrophins, especially the NGF.

Toll-Like Receptor 2 and Mincle Cooperatively Sense Corynebacterial Cell Wall Glycolipids.

PubMed

Schick, Judith; Etschel, Philipp; Bailo, Rebeca; Ott, Lisa; Bhatt, Apoorva; Lepenies, Bernd; Kirschning, Carsten; Burkovski, Andreas; Lang, Roland

2017-07-01

Nontoxigenic Corynebacterium diphtheriae and Corynebacterium ulcerans cause invasive disease in humans and animals. Host sensing of corynebacteria is largely uncharacterized, albeit the recognition of lipoglycans by Toll-like receptor 2 (TLR2) appears to be important for macrophage activation by corynebacteria. The members of the order Corynebacterineae (e.g., mycobacteria, nocardia, and rhodococci) share a glycolipid-rich cell wall dominated by mycolic acids (termed corynomycolic acids in corynebacteria). The mycolic acid-containing cord factor of mycobacteria, trehalose dimycolate, activates the C-type lectin receptor (CLR) Mincle. Here, we show that glycolipid extracts from the cell walls of several pathogenic and nonpathogenic Corynebacterium strains directly bound to recombinant Mincle in vitro Macrophages deficient in Mincle or its adapter protein Fc receptor gamma chain (FcRγ) produced severely reduced amounts of granulocyte colony-stimulating factor (G-CSF) and of nitric oxide (NO) upon challenge with corynebacterial glycolipids. Consistently, cell wall extracts of a particular C. diphtheriae strain (DSM43989) lacking mycolic acid esters neither bound Mincle nor activated macrophages. Furthermore, TLR2 but not TLR4 was critical for sensing of cell wall extracts and whole corynebacteria. The upregulation of Mincle expression upon encountering corynebacteria required TLR2. Thus, macrophage activation by the corynebacterial cell wall relies on TLR2-driven robust Mincle expression and the cooperative action of both receptors. Copyright © 2017 American Society for Microbiology.

Toll-Like Receptor 2 and Mincle Cooperatively Sense Corynebacterial Cell Wall Glycolipids

PubMed Central

Schick, Judith; Etschel, Philipp; Bailo, Rebeca; Ott, Lisa; Bhatt, Apoorva; Lepenies, Bernd; Kirschning, Carsten

2017-01-01

ABSTRACT Nontoxigenic Corynebacterium diphtheriae and Corynebacterium ulcerans cause invasive disease in humans and animals. Host sensing of corynebacteria is largely uncharacterized, albeit the recognition of lipoglycans by Toll-like receptor 2 (TLR2) appears to be important for macrophage activation by corynebacteria. The members of the order Corynebacterineae (e.g., mycobacteria, nocardia, and rhodococci) share a glycolipid-rich cell wall dominated by mycolic acids (termed corynomycolic acids in corynebacteria). The mycolic acid-containing cord factor of mycobacteria, trehalose dimycolate, activates the C-type lectin receptor (CLR) Mincle. Here, we show that glycolipid extracts from the cell walls of several pathogenic and nonpathogenic Corynebacterium strains directly bound to recombinant Mincle in vitro. Macrophages deficient in Mincle or its adapter protein Fc receptor gamma chain (FcRγ) produced severely reduced amounts of granulocyte colony-stimulating factor (G-CSF) and of nitric oxide (NO) upon challenge with corynebacterial glycolipids. Consistently, cell wall extracts of a particular C. diphtheriae strain (DSM43989) lacking mycolic acid esters neither bound Mincle nor activated macrophages. Furthermore, TLR2 but not TLR4 was critical for sensing of cell wall extracts and whole corynebacteria. The upregulation of Mincle expression upon encountering corynebacteria required TLR2. Thus, macrophage activation by the corynebacterial cell wall relies on TLR2-driven robust Mincle expression and the cooperative action of both receptors. PMID:28483856

Smad2-dependent glycosaminoglycan elongation in aortic valve interstitial cells enhances binding of LDL to proteoglycans.

PubMed

Osman, Narin; Grande-Allen, K Jane; Ballinger, Mandy L; Getachew, Robel; Marasco, Silvana; O'Brien, Kevin D; Little, Peter J

2013-01-01

Calcific aortic valve disease is a progressive condition that shares some common pathogenic features with atherosclerosis. Transforming growth factor-β1 is a recognized mediator of atherosclerosis and is expressed in aortic valve lesions. Transforming growth factorβ1 stimulates glycosaminoglycan elongation of proteoglycans that is associated with increased lipid binding. We investigated the presence of transforming growth factor-β1 and downstream signaling intermediates in diseased human aortic valves and the effects of activated transforming growth factor-β1 receptor signaling on aortic valve interstitial cell proteoglycan synthesis and lipid binding as a possible mechanism for the initiation of the early lesion of calcific aortic valve disease. Diseased human aortic valve leaflets demonstrated strong immunohistochemical staining for transforming growth factor-β1 and phosphorylated Smad2/3. In primary porcine aortic valve interstitial cells, Western blots showed that transforming growth factor-β1 stimulated phosphorylation in both the carboxy and linker regions of Smad2/3, which was inhibited by the transforming growth factor-β1 receptor inhibitor SB431542. Gel electrophoresis and size exclusion chromatography demonstrated that SB431542 decreased transforming growth factor-β1-mediated [(35)S]-sulfate incorporation into proteoglycans in a dose-dependent manner. Further, in proteoglycans derived from transforming growth factor-β1-treated valve interstitial cells, gel mobility shift assays demonstrated that inhibition of transforming growth factor-β1 receptor signaling resulted in decreased lipid binding. Classic transforming growth factor-β1 signaling is present in human aortic valves in vivo and contributes to the modification of proteoglycans expressed by valve interstitial cells in vitro. These findings suggest that transforming growth factor-β1 may promote increased low-density lipoprotein binding in the early phases of calcific aortic valve disease. Copyright © 2013 Elsevier Inc. All rights reserved.

Induction of cyclooxygenase-2 expression by prostaglandin E2 stimulation of the prostanoid EP4 receptor via coupling to Gαi and transactivation of the epidermal growth factor receptor in HCA-7 human colon cancer cells.

PubMed

Yoshida, Kenji; Fujino, Hiromichi; Otake, Sho; Seira, Naofumi; Regan, John W; Murayama, Toshihiko

2013-10-15

Increased expressions of cyclooxygenase-2 (COX-2) and its downstream metabolite, prostaglandin E2 (PGE2), are well documented events in the development of colorectal cancer. Interestingly, PGE2 itself can induce the expression of COX-2 thereby creating the potential for positive feedback. Although evidence for such a positive feedback has been previously described, the specific E-type prostanoid (EP) receptor subtype that mediates this response, as well as the relevant signaling pathways, remain unclear. We now report that the PGE2 stimulated induction of COX-2 expression in human colon cancer HCA-7 cells is mediated by activation of the prostanoid EP4 receptor subtype and is followed by coupling of the receptor to Gαi and the activation of phosphatidylinositol 3-kinase. Subsequent activation of metalloproteinases releases membrane bound heparin-binding epidermal growth factor-like growth factor resulting in the transactivation of epidermal growth factor receptors and the activation of the extracellular signal-regulated kinases and induction of COX-2 expression. This induction of COX-2 expression by PGE2 stimulation of the prostanoid EP4 receptor may underlie the upregulation of COX-2 during colorectal cancer and appears to be an early event in the process of tumorigenesis. © 2013 Elsevier B.V. All rights reserved.

Activation‐Induced Killer Cell Immunoglobulin‐like Receptor 3DL2 Binding to HLA–B27 Licenses Pathogenic T Cell Differentiation in Spondyloarthritis

PubMed Central

Ridley, Anna; Hatano, Hiroko; Wong‐Baeza, Isabel; Shaw, Jacqueline; Matthews, Katherine K.; Al‐Mossawi, Hussein; Ladell, Kristin; Price, David A.; Bowness, Paul

2016-01-01

Objective In the spondyloarthritides (SpA), increased numbers of CD4+ T cells express killer cell immunoglobulin‐like receptor 3DL2 (KIR‐3DL2). The aim of this study was to determine the factors that induce KIR‐3DL2 expression, and to characterize the relationship between HLA–B27 and the phenotype and function of KIR‐3DL2–expressing CD4+ T cells in SpA. Methods In total, 34 B27+ patients with SpA, 28 age‐ and sex‐matched healthy controls (20 B27− and 8 B27+), and 9 patients with rheumatoid arthritis were studied. KIR-3DL2 expression and other phenotypic characteristics of peripheral blood and synovial fluid CD4+ T cells were studied by flow cytometry, quantitative polymerase chain reaction, and Western blotting. T cell receptor clonality was determined by template‐switch anchored reverse transcription–polymerase chain reaction and sequencing analysis. Cytokines were measured by enzyme‐linked immunosorbent assay. Results Cellular activation induced KIR‐3DL2 expression on both naive and effector CD4+ T cells. KIR‐3DL2 binding to B27+ cells promoted expression of KIR‐3DL2, the Th17‐specific transcription factor retinoic acid receptor–related orphan nuclear receptor γt, and the antiapoptotic factor B cell lymphoma 2. KIR‐3DL2+CD4+ T cells in patients with ankylosing spondylitis were oligoclonal and enriched for markers of T cell activation and for the gut homing receptor CCR9. In the presence of B27+ antigen‐presenting cells, KIR‐3DL2+CD4+ T cells produced less interleukin‐2 (IL‐2) but more IL‐17. This effect was blocked by HC10, an antibody that inhibits the binding of KIR‐3DL2 to B27 heavy chains. Conclusion KIR‐3DL2 binding to HLA–B27 licenses Th17 cell differentiation in SpA. These findings raise the therapeutic potential of targeting HLA–B27–KIR‐3DL2 interactions for the treatment of B27+ patients with SpA. PMID:26841353

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagata, Yosuke, E-mail: cynagata@mail.ecc.u-tokyo.ac.jp; Ohashi, Kazuya; Wada, Eiji

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 epidermalmore » 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 receptor.« less

IL-3 specifically inhibits GM-CSF binding to the higher affinity receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taketazu, F.; Chiba, S.; Shibuya, K.

1991-02-01

The inhibition of binding between human granulocyte-macrophage colony-stimulating factor (GM-CSF) and its receptor by human interleukin-3 (IL-3) was observed in myelogenous leukemia cell line KG-1 which bore the receptors both for GM-CSF and IL-3. In contrast, this phenomenon was not observed in histiocytic lymphoma cell line U-937 or in gastric carcinoma cell line KATO III, both of which have apparent GM-CSF receptor but an undetectable IL-3 receptor. In KG-1 cells, the cross-inhibition was preferentially observed when the binding of GM-CSF was performed under the high-affinity binding condition; i.e., a low concentration of 125I-GM-CSF was incubated. Scatchard analysis of 125I-GM-CSF bindingmore » to KG-1 cells in the absence and in the presence of unlabeled IL-3 demonstrated that IL-3 inhibited GM-CSF binding to the higher-affinity component of GM-CSF receptor on KG-1 cells. Moreover, a chemical cross-linking study has revealed that the cross-inhibition of the GM-CSF binding observed in KG-1 cells is specific for the beta-chain, Mr 135,000 binding protein which has been identified as a component forming the high-affinity GM-CSF receptor existing specifically on hemopoietic cells.« less

Activation of Estrogen Receptor Transfected into a Receptor-Negative Brest Cancer Cell Line Decreases the Metastatic and Invasive Potential of the Cells

NASA Astrophysics Data System (ADS)

Garcia, Marcel; Derocq, Danielle; Freiss, Gilles; Rochefort, Henri

1992-12-01

Breast cancers containing estrogen receptors are responsive to antiestrogen treatment and have a better prognosis than estrogen receptor-negative tumors. The loss of estrogen and progesterone receptors appears to be associated with a progression to less-differentiated tumors. We transfected the human estrogen receptor into the estrogen receptor-negative metastatic breast cancer cell line MDA-MB-231 in an attempt to restore their sensitivity to antiestrogens. Two stable sublines of MDA-MB-231 cells (HC1 and HE5) expressing functional estrogen receptors were studied for their ability to grow and invade in vitro and to metastasize in athymic nude mice. The number and size of lung metastases developed by these two sublines in ovariectomized nude mice was not markedly altered by tamoxifen but was inhibited 3-fold by estradiol. Estradiol also significantly inhibited in vitro cell proliferation of these sublines and their invasiveness in Matrigel, a reconstituted basement membrane, whereas the antiestrogens 4-hydroxytamoxifen and ICI 164,384 reversed these effects. These results show that estradiol inhibits the metastatic ability of estrogen receptornegative breast cancer cells following transfection with the estrogen receptor, whereas estrogen receptor-positive breast cancers are stimulated by estrogen, indicating that factors other than the estrogen receptor are involved in progression toward hormone independence. Reactivation or transfer of the estrogen receptor gene can therefore be considered as therapeutic approaches to hormone-independent cancers

Pathophysiological roles of P2 receptors in glial cells.

PubMed

Abbracchio, Maria P; Verderio, Claudia

2006-01-01

Extracellular nucleotides act through specific receptors on target cells: the seven ionotropic P2X and the eight G protein-coupled P2Y receptors. All these receptors are expressed by brain astroglia and microglia. In astrocytes, P2 receptors have been implicated in short-term calcium-dependent cell-cell communication. Upon mechanical stimulation or activation by other transmitters, astrocytes release ATP and respond to ATP with a propagating wave of intracellular calcium increases, allowing a homotypic astrocyte-astrocyte communication, as well as an heterotypic signalling which also involves neurons, oligodendrocytes and microglia. Astrocytic P2 receptors also mediate reactive astrogliosis, a reaction contributing to neuronal death in neurodegenerative diseases. Signalling leading to inflammatory astrogliosis involves induction of cyclo-oxygenase 2 through stimulation of ERK1,2 and of the transcriptional factors AP-1 and NF-kappaB. Microglia also express several P2 receptors linked to intracellular calcium increases. P2 receptor subtypes are differentially regulated by typical proinflammatory signals for these cells (e.g. lipopolysaccharide), suggesting specific roles in brain immune responses. Globally, these findings highlight the roles of P2 receptors in glial cell pathophysiology suggesting a contribution to neurodegenerative diseases characterized by excessive gliosis and neuro-inflammation. They also open up the possibility of modulating brain damage by ligands selectively targeting the specific P2 receptor subtypes involved in the gliotic response.

Dependence of Relative Expression of NTR1 and EGFR on Cell Density and Extracellular pH in Human Pancreatic Cancer Cell Lines

PubMed Central

Olszewski-Hamilton, Ulrike; Hamilton, Gerhard

2011-01-01

Pancreatic adenocarcinoma is a devastating disease characterized by early dissemination and poor prognosis. These solid tumors express receptors for neuropeptides like neurotensin (NT) or epidermal growth factor (EGF) and exhibit acidic regions when grown beyond a certain size. We previously demonstrated increases in intracellular Ca2+ levels, intracellular pH and interleukin-8 (IL-8) secretion in BxPC-3 and PANC-1 pancreatic cancer cells in response to a stable NT analog. The present study aimed at investigation of the dependence of the relative expression of NT receptor 1 (NTR1) and EGFR in BxPC-3 and MIA PaCa-2 cells on cell density and extracellular pH (pHe). MTT assays revealed the NTR1 inhibitor SR 142948-sensitive Lys8-ψ-Lys9NT (8–13)-induced proliferation in BxPC-3 and PANC-1 cells. Confluent cultures of BxPC3 and HT-29 lines exhibited highest expression of NTR1 and lowest of EGFR and expression of NTR1 was maximal at slightly acidic pHe. IL-8 production was stimulated by Lys8-ψ-Lys9NT (8–13) and even enhanced at both acidic and alkaline pHe in BxPC-3 and PANC-1 cells. In conclusion, our in vitro study suggests that one contributing factor to the minor responses obtained with EGFR-directed therapy may be downregulation of this receptor in tumor cell aggregates, possibly resulting in acquisition of a more aggressive phenotype via other growth factor receptors like NTR1. PMID:24212612

Spared pre-irradiated area in pustular lesions induced by icotinib showing decreased expressions of CD1a+ langerhans cells and FGFR2.

PubMed

Zhao, Qiong; Wang, Yi Na; Wang, Bo

2013-02-01

Icotinib hydrochloride, a novel inhibitor of epidermal growth factor receptor tyrosine kinase, has been approved by the State Food and Drug Administration for the treatment of advanced non-small-cell lung cancer. Up to date, cutaneous response to icotinib is largely unknown. Here we report an uncommon lesional phenomenon in a 56-year-old Chinese male with non-small-cell lung cancer, who received icotinib as a second-line treatment. Characteristic papulopustular rash on the chest and back was observed 4 days later. Interestingly, the rash completely spares a pre-irradiated area. The immunohistochemical study in the lesional skin area and spared skin area revealed a significant decrease in CD1a(+) Langerhans cells, Ki-67 as well as FGFR2 in the spared area than in the lesional area. Thus, the present case indicated that loss of the basal layer of proliferative cells and antigen-presenting cells (Langerhans cell), as well as the down-regulation of FGFR2 signaling in the pre-irradiated skin area, may join forces in inhibiting icotinib-associated cutaneous reactions. To our knowledge, this is the first report of both lesional area and lesion-spared area in a Chinese male receiving treatment with a new epidermal growth factor receptor-tyrosine kinase inhibitor (icotinib). The immunohistochemical reactions described here also provide new insight into the pathogenesis of epidermal growth factor receptor-tyrosine kinase inhibitor-related skin toxicities, and the role that other tyrosine kinase receptors (including FGFR) played in non-small-cell lung cancer.

U.S. Army Aeromedical Research Laboratory Annual Progress Report Fiscal Year 2010

DTIC Science & Technology

2011-03-01

S. (2010). Epidermal growth factor receptor transactivation by the cannabinoid receptor (CB1) and transient receptor potential vanilloid 1 ( TRPV1 ...induced by TRPV1 in human corneal epithelial cells. Proceedings of the Association for Research in Vision and Ophthalmology Annual Meeting, 5899/A94...presented “Novel TRPV1 -linked cell signaling pathways mediating inflammatory responses and wound healing in human corneal epithelial cells” at the Fouth

Novel Drugs that Target ErbB2

DTIC Science & Technology

2011-05-01

Fig. 3C). 3. Role of cannabinoid receptors BA-induced downregulation of Sp transcription factors was proteasome-independent (Fig. 2) and...cancer cell lines show that cannabinoids (CBs) decrease Sp proteins (data not shown), the effects of CB1 and CB2 receptor antagonists AM251 and AM630...were observed in MDA-MB-453 cells confirming a role for the cannabinoid receptors in mediating the effects of BA on Sp and Sp-regulated genes

Development of regulatory T cells requires IL-7Rα stimulation by IL-7 or TSLP

PubMed Central

Mazzucchelli, Renata; Hixon, Julie A.; Spolski, Rosanne; Chen, Xin; Li, Wen Qing; Hall, Veronica L.; Willette-Brown, Jami; Hurwitz, Arthur A.; Leonard, Warren J.

2008-01-01

Interleukin-7 (IL-7), a cytokine produced by stromal cells, is required for thymic development and peripheral homeostasis of most major subsets of T cells. We examined whether regulatory T (Treg) cells also required the IL-7 pathway by analyzing IL-7Rα−/− mice. We observed a striking reduction in cells with the Treg surface phenotype (CD4, CD25, GITR (glucocorticoid-induced tumor necrosis factor [TNF]-like receptor), CD45RB, CD62L, CD103) or intracellular markers (cytotoxic T-lymphocyte–associated antigen-4, CTLA-4, and forkhead box transcription factor 3, Foxp3). Foxp3 transcripts were virtually absent in IL-7Rα−/− lymphoid tissues, and no Treg cell suppressive activity could be detected. There are 2 known ligands for IL-7Rα: IL-7 itself and thymic stromal lymphopoietin (TSLP). Surprisingly, mice deficient in IL-7 or the other chain of the TSLP receptor (TSLPR) developed relatively normal numbers of Treg cells. Combined deletion of IL-7 and TSLP receptor greatly reduced Treg cell development in the thymus but was not required for survival of mature peripheral Treg cells. We conclude that Treg cells, like other T cells, require signals from the IL-7 receptor, but unlike other T cells, do not require IL-7 itself because of at least partially overlapping actions of IL-7 and TSLP for development of Treg cells. PMID:18664628

The multiple roles of the innate immune system in the regulation of apoptosis and inflammation in the brain.

PubMed

Griffiths, Mark R; Gasque, Philippe; Neal, James W

2009-03-01

Central nervous system (CNS) tissues contain cells (i.e. glia and neurons) that have innate immune functions. These cells express a range of receptors that are capable of detecting and clearing apoptotic cells and regulating inflammatory responses. Phagocytosis of apoptotic cells is a nonphlogistic (i.e. noninflammatory) process that provides immune regulation through anti-inflammatory cytokines andregulatory T cells. Neurons and glia express cellular death signals, including CD95Fas/CD95L, FasL, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and tumor necrosis factor receptor 1 (TNFR), through which they can trigger apoptosis in T cells and other infiltrating cells. Microglia, astrocytes, ependymal cells, and neurons express defense collagens and scavenger and phagocytic receptors that recognize apoptotic cells displaying apoptotic cell-associated molecular patterns, which serve as markers of "altered self." Glia also express pentraxins and complement proteins (C1q, C3b, and iC3b) that opsonize apoptotic cells, making them targets for the phagocytic receptors CR3 and CR4. Immunoregulatory molecules such as the complement regulator CD46 are lost from apoptotic cells and stimulate phagocytosis, whereas the expression of CD47 and CD200 is upregulated during apoptosis; this inhibits proinflammatory microglial cytokine expression, thereby reducing the severity of inflammation. This review outlines the cellular pathways used for the detection and phagocytosis of apoptotic cells in vitro and in experimental models of CNS inflammation.

Mitogenic signals and transforming potential of Nyk, a newly identified neural cell adhesion molecule-related receptor tyrosine kinase.

PubMed Central

Ling, L; Kung, H J

1995-01-01

Nyk/Mer is a recently identified receptor tyrosine kinase with neural cell adhesion molecule-like structure (two immunoglobulin G-like domains and two fibronectin III-like domains) in its extracellular region and belongs to the Ufo/Axl family of receptors. The ligand for Nyk/Mer is presently unknown, as are the signal transduction pathways mediated by this receptor. We constructed and expressed a chimeric receptor (Fms-Nyk) composed of the extracellular domain of the human colony-stimulating factor 1 receptor (Fms) and the transmembrane and cytoplasmic domains of human Nyk/Mer in NIH 3T3 fibroblasts in order to investigate the mitogenic signaling and biochemical properties of Nyk/Mer. Colony-stimulating factor 1 stimulation of the Fms-Nyk chimeric receptor in transfected NIH 3T3 fibroblasts leads to a transformed phenotype and generates a proliferative response in the absence of other growth factors. We show that phospholipase C gamma, phosphatidylinositol 3-kinase/p70 S6 kinase, Shc, Grb2, Raf-1, and mitogen-activated protein kinase are downstream components of the Nyk/Mer signal transduction pathways. In addition, Nyk/Mer weakly activates p90rsk, while stress-activated protein kinase, Ras GTPase-activating protein (GAP), and GAP-associated p62 and p190 proteins are not activated or tyrosine phosphorylated by Nyk/Mer. An analysis comparing the Nyk/Mer signal cascade with that of the epidermal growth factor receptor indicates substrate preferences by these two receptors. Our results provide a detailed description of the Nyk/Mer signaling pathways. Given the structural similarity between the Ufo/Axl family receptors, some of the information may also be applied to other members of this receptor tyrosine kinase family. PMID:8524223

The BAFF receptor TACI controls IL-10 production by regulatory B cells and CLL B cells.

PubMed

Saulep-Easton, D; Vincent, F B; Quah, P S; Wei, A; Ting, S B; Croce, C M; Tam, C; Mackay, F

2016-01-01

Interleukin (IL)-10-producing B cells (B10 cells) have emerged as important regulatory elements with immunosuppressive roles. Chronic lymphocytic leukemia (CLL) B cells also secrete IL-10 and share features of B10 cells, suggesting a possible contribution of CLL B cells to immunosuppression in CLL patients. Factors controlling the emergence of B10 cells are not known. B-cell-activating factor of the tumor necrosis factor (TNF) family (BAFF) is critical for B-cell maturation and survival, and is implicated in the development and progression of CLL. We sought to investigate the role of BAFF in the emergence of IL-10-producing regulatory B cells in healthy donors and CLL patients. Here, we report that BAFF signaling promotes IL-10 production by CLL B cells in a mouse model of CLL and in CLL patients. Moreover, BAFF-mediated IL-10 production by normal and CLL B cells is mediated via its receptor transmembrane activator and cyclophilin ligand interactor. Our work uncovered a major targetable pathway important for the generation of regulatory B cells that is detrimental to immunity in CLL.

Special Education.

PubMed

Kozutsumi

1996-01-01

HEMOPOIETIC FACTORS AND BLOOD CELL PROLIFERATION AND DIFFERENTIATION: Blood cells are generally classified into three cell lineages: erythrocytes, granulocytes and megakaryocytes. In the bone marrow, pluripotent stem cells differentiate into either the lymphoid stem cell line, where they are further induced to differentiate into B- or T-derived lymphocytes, or the myeloid stem cell (CFU-GEMM) line, where they are further induced to become erythrocytes, granulocytes (neutrophils, eosinophils or basophils), macrophages or megakaryocytes (platelets). Proliferation and differentiation of blood cells in the bone marrow are regulated by hemopoietic factors. Hemopoietic factors include those that are continuously produced, such as EPO, G-CSF and thrombopoietin (TPO), and those that are produced on demand in response to inflammation and infection, such as IL-3, IL-11 and GM-CSF. In recent years the genes for hemopoietic factors which regulate erythrocytes and granulocytes have been cloned using the techniques of genetic engineering. In 1994 the gene for TPO was cloned. TPO acts specifically on megakaryocytes. PROLIFERATION AND DIFFERENTIATION OF ERYTHROCYTIC CELLS: The earliest cells destined to become erythrocytes which differentiate from the myeloid stem cells (CFU-GEMM) are early phase erythroblast progenitor cells called BFU-E cells. After the BFU-E cells have undergone several divisions, they differentiate into late phase erythroblast progenitor cells called CFU-E cells. After passing through the proerythroblast stage, the CFU-E cells become erythroblasts. Erythroblasts can be confirmed by light microscope as belonging to the erythroid cell line. Erythroblasts mature and become enucleated reticulocytes, which are then released from the bone marrow into the blood, thus becoming mature erythrocytes. Proliferation and differentiation of the erythroid progenitor cells are regulated by erythropoietin (EPO), which is primarily produced by the kidneys. In 1985 genomic DNA and cDNA for human EPO were cloned, and it was learned that the mature protein is a glycoprotein consisting of 165 amino acids and having a molecular weight of about 30,000. There is powerful evidence to suggest that EPO is produced by peritubular cells of the renal cortex. When the hematocrit drops for some reason and hypoxia occurs, the number of EPO-producing cells increases and EPO production rises in the kidneys. CFU-E cells are the main target cells for EPO. EPO receptors are expressed along the lineage from BFU-E cells to proerythroblasts, with peak expression found in CFU-E cells. The EPO receptor, which was cloned in 1989, belongs to the cytokine receptor family, transduces the EPO signal to the interior of the cell, and brings about the proliferation and differentiation of CFU-E cells. PROLIFERATION AND DIFFERENTIATION OF GRANULOCYTIC CELLS: The earliest cells destined to become neutrophils and macrophages which differentiate from the pluripotent stem cells are called granulocyte-macrophage progenitor (CFU-GM) cells. The CFU-GM cells are affected by colony-stimulating factors and become either CFU-G or CFU-M cells. Ultimately, they differentiate into mature neutrophils or macrophages. The main factor stimulating the proliferation and differentiation of neutrophils is the granulocyte colony-stimulating factor (G-CSF). CFU-GM cells are stimulated by G-CSF in the bone marrow, pass through the CFU-G stage, and become myeloblasts, which are the most primitive neutrophils that can be morphologically distinguished. Myeloblasts continue to divide and differentiate, and they mature into neutrophils, which then lose their ability to divide. Mature neutrophils are not immediately released into the blood, but rather are stored within the bone marrow. Neutrophils that have been released into the blood reside in the marginal granulocyte pool or the circulating granulocyte pool, and they later egress into tissues. G-CSF is produced by cells such as monocytes, macrophages and bone marrow stromal cells, and its action is almost entirely selective for the proliferation of neutrophils. The cDNA for G-CSF was cloned in 1986, and it was learned that the mature protein is a glycoprotein consisting of 174 amino acids and having a molecular weight of about 20,000. When G-CSF is administered to a patient it causes the release of mature neutrophils from the marrow into the peripheral blood. G-CSF also enhances neutrophil function in the presence of bacterial products, and it acts on mature neutrophils to enhance cellular motility, the production of bioactive oxygen, and microbicidal activity. The cDNA for the G-CSF receptor was cloned in 1990, and its receptor belongs to the cytokine receptor family. The human G-CSF receptor consists of 813 amino acids and has an approximate molecular weight of 100,000 to 130,000. The G-CSF receptor signal is mediated by the JAK-1 and JAK-2 tyrosine kinases.

Synergic Effects of Mycoplasmal Lipopeptides and Extracellular ATP on Activation of Macrophages

PubMed Central

Into, Takeshi; Fujita, Mari; Okusawa, Tsugumi; Hasebe, Akira; Morita, Manabu; Shibata, Ken-Ichiro

2002-01-01

Mycoplasmal lipopeptides S-(2,3-bispalmitoyloxypropyl)-CGDPKHSPKSF and S-(2,3-bispalmitoyloxypropyl)-CGNNDESNISFKEK activated a monocytic cell line, THP-1 cells, to produce tumor necrosis factor alpha. The activity of the lipopeptides was augmented by ATP in a dose-dependent manner. In addition, the level of expression of mRNAs for tumor necrosis factor alpha and interleukin-1β, -6, and -8 was also upregulated by the lipopeptides and/or extracellular ATP, but that of interleukin-10 was not. The P2X purinergic receptor antagonists pyridoxal phosphate 6-azophenyl 2′,4′-disulfonic acid and periodate-oxidized ATP suppressed the activity of ATP to augment the activation of THP-1 cells by the lipopeptides, suggesting that P2X receptors play important roles in the activity of ATP. The nuclear factor κB inhibitor dexamethasone also suppressed the activity, suggesting that the activity of ATP is dependent upon the nuclear factor κB. Thus, these results suggest that the interaction of extracellular ATP with the P2X receptors is attributed to the activity of ATP to augment the activation of THP-1 cells by mycoplasmal lipopeptides. PMID:12065499

Expression of inhibitory receptors and polyfunctional responses of T cells are linked to the risk of congenital transmission of T. cruzi

PubMed Central

Thomas, María Carmen; Carrilero, Bartolomé; González, John Mario; Cuéllar, Adriana; Segovia, Manuel; Puerta, Concepción Judith

2017-01-01

Congenital T. cruzi infections involve multiple factors in which complex interactions between the parasite and the immune system of pregnant women play important roles. In this study, we used an experimental murine model of chronic infection with T. cruzi to evaluate the changes in the expression of inhibitory receptors and the polyfunctionality of T cells during gestation and their association with congenital transmission rate of T. cruzi infection. The results showed that pregnant naïve mice had a higher percentage of CD4+ and CD8+ T cells that expressed inhibitory receptors than cells from non-pregnant naïve mice. However, in mice chronically infected with T. cruzi, gestation induced a significant decrease in the frequency of T cells that expressed or co-expressed inhibitory receptors, as well as an increase in the frequency of polyfunctional CD4+ and CD8+ T cells. This different behavior may be due to the breakdown in the infected mice of the gestation-induced immune homeostasis, probably to control the parasite load. Remarkably, it was observed that the mothers that transmitted the parasite had a higher frequency of T cells that expressed and co-expressed inhibitory receptors as well as a lower frequency of polyfunctional parasite-specific T cells than those that did not transmit it, even though the parasitemia load was similar in both groups. All together these data suggest that the maternal immune profile of the CD4+ and CD8+ T cells could be a determining factor in the congenital transmission of T. cruzi. PMID:28598971

Neuropilin 1 Receptor Is Up-Regulated in Dysplastic Epithelium and Oral Squamous Cell Carcinoma.

PubMed

Shahrabi-Farahani, Shokoufeh; Gallottini, Marina; Martins, Fabiana; Li, Erik; Mudge, Dayna R; Nakayama, Hironao; Hida, Kyoko; Panigrahy, Dipak; D'Amore, Patricia A; Bielenberg, Diane R

2016-04-01

Neuropilins are receptors for disparate ligands, including proangiogenic factors such as vascular endothelial growth factor and inhibitory class 3 semaphorin (SEMA3) family members. Differentiated cells in skin epithelium and cutaneous squamous cell carcinoma highly express the neuropilin-1 (NRP1) receptor. We examined the expression of NRP1 in human and mouse oral mucosa. NRP1 was significantly up-regulated in oral epithelial dysplasia and oral squamous cell carcinoma (OSCC). NRP1 receptor localized to the outer suprabasal epithelial layers in normal tongue, an expression pattern similar to the normal skin epidermis. However, dysplastic tongue epithelium and OSCC up-regulated NRP1 in basal and proliferating epithelial layers, a profile unseen in cutaneous squamous cell carcinoma. NRP1 up-regulation is observed in a mouse carcinogen-induced OSCC model and in human tongue OSCC biopsies. Human OSCC cell lines express NRP1 protein in vitro and in mouse tongue xenografts. Sites of capillary infiltration into orthotopic OSCC tumors correlate with high NRP1 expression. HSC3 xenografts, which express the highest NRP1 levels of the cell lines examined, showed massive intratumoral lymphangiogenesis. SEMA3A inhibited OSCC cell migration, suggesting that the NRP1 receptor was bioactive in OSCC. In conclusion, NRP1 is regulated in the oral epithelium and is selectively up-regulated during epithelial dysplasia. NRP1 may function as a reservoir to sequester proangiogenic ligands within the neoplastic compartment, thereby recruiting neovessels toward tumor cells. Copyright © 2016 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Receptor-like Molecules on Human Intestinal Epithelial Cells Interact with an Adhesion Factor from Lactobacillus reuteri

PubMed Central

MATSUO, Yosuke; MIYOSHI, Yukihiro; OKADA, Sanae; SATOH, Eiichi

2012-01-01

A surface protein of Lactobacillus reuteri, mucus adhesion-promoting protein (MapA), is considered to be an adhesion factor. MapA is expressed in L. reuteri strains and adheres to piglet gastric mucus, collagen type I, and human intestinal epithelial cells such as Caco-2. The aim of this study was to identify molecules that mediate the attachment of MapA from L. reuteri to the intestinal epithelial cell surface by investigating the adhesion of MapA to receptor-like molecules on Caco-2 cells. MapA-binding receptor-like molecules were detected in Caco-2 cell lysates by 2D-PAGE. Two proteins, annexin A13 (ANXA13) and paralemmin (PALM), were identified by MALDI TOF-MS. The results of a pull-down assay showed that MapA bound directly to ANXA13 and PALM. Fluorescence microscopy studies confirmed that MapA binding to ANXA13 and PALM was colocalized on the Caco-2 cell membrane. To evaluate whether ANXA13 and PALM are important for MapA adhesion, ANXA13 and PALM knockdown cell lines were established. The adhesion of MapA to the abovementioned cell lines was reduced compared with that to wild-type Caco-2 cells. These knockdown experiments established the importance of these receptor-like molecules in MapA adhesion. PMID:24936355

Resveratrol prevents angiotensin II-induced hypertrophy of vascular smooth muscle cells through the transactivation of growth factor receptors.

PubMed

Hossain, Ekhtear; Anand-Srivastava, Madhu B

2017-08-01

We previously showed that augmented levels of endogenous angiotensin II (AngII) contribute to vascular smooth muscle cell (VSMC) hypertrophy through the transactivation of growth factor receptors in spontaneously hypertensive rats. Resveratrol (RV), a polyphenolic component of red wine, has also been shown to attenuate AngII-evoked VSMC hypertrophy; however, the molecular mechanism mediating this response is obscure. The present study was therefore undertaken to examine whether RV could prevent AngII-induced VSMC hypertrophy through the transactivation of growth factor receptor and associated signaling pathways. AngII treatment of VSMC enhanced the protein synthesis that was attenuated towards control levels by RV pretreatment as well as by the inhibitors of NADPH oxidase, c-Src, and growth factor receptors. Furthermore, RV pretreatment also inhibited enhanced levels of superoxide anion, NADPH oxidase activity, increased expression of NADPH oxidase subunits, and phosphorylation of c-Src, EGF-R, PDGE-R, ERK1/2, and AKT1/2. In conclusion, these results indicate that RV attenuates AngII-induced VSMC hypertrophy through the inhibition of enhanced oxidative stress and activation of c-Src, growth factor receptors, and MAPK/AKT signaling. We suggest that RV could be used as a therapeutic agent in the treatment of vascular complications associated with hypertension and hypertrophy.

The Fn14 cytoplasmic tail binds tumour-necrosis-factor-receptor-associated factors 1, 2, 3 and 5 and mediates nuclear factor-kappaB activation.

PubMed Central

Brown, Sharron A N; Richards, Christine M; Hanscom, Heather N; Feng, Sheau-Line Y; Winkles, Jeffrey A

2003-01-01

Fn14 is a growth-factor-inducible immediate-early-response gene encoding a 102-amino-acid type I transmembrane protein. The human Fn14 protein was recently identified as a cell-surface receptor for the tumour necrosis factor (TNF) superfamily member named TWEAK (TNF-like weak inducer of apoptosis). In the present paper, we report that the human TWEAK extracellular domain can also bind the murine Fn14 protein. Furthermore, site-specific mutagenesis and directed yeast two-hybrid interaction assays revealed that the TNFR-associated factor (TRAF) 1, 2, 3 and 5 adaptor molecules bind the murine Fn14 cytoplasmic tail at an overlapping, but non-identical, amino acid sequence motif. We also found that TWEAK treatment of quiescent NIH 3T3 cells stimulates inhibitory kappaBalpha phosphorylation and transcriptional activation of a nuclear factor-kappaB (NF-kappaB) enhancer/luciferase reporter construct. Fn14 overexpression in transiently transfected NIH 3T3 cells also promotes NF-kappaB activation, and this cellular response requires an intact TRAF binding site. These results indicate that Fn14 is a functional TWEAK receptor that can associate with four distinct TRAF family members and stimulate the NF-kappaB transcription factor signalling pathway. PMID:12529173

Crystallization of a 2:2 complex of granulocyte-colony stimulating factor (GCSF) with the ligand-binding region of the GCSF receptor

PubMed Central

Honjo, Eijiro; Tamada, Taro; Maeda, Yoshitake; Koshiba, Takumi; Matsukura, Yasuko; Okamoto, Tomoyuki; Ishibashi, Matsujiro; Tokunaga, Masao; Kuroki, Ryota

2005-01-01

The granulocyte-colony stimulating factor (GCSF) receptor receives signals for regulating the maturation, proliferation and differentiation of the precursor cells of neutrophilic granulocytes. The signalling complex composed of two GCSFs (GCSF, 19 kDa) and two GCSF receptors (GCSFR, 34 kDa) consisting of an Ig-like domain and a cytokine-receptor homologous (CRH) domain was crystallized. A crystal of the complex was grown in 1.0 M sodium formate and 0.1 M sodium acetate pH 4.6 and belongs to space group P41212 (or its enantiomorph P43212), with unit-cell parameters a = b = 110.1, c = 331.8 Å. Unfortunately, this crystal form did not diffract beyond 5 Å resolution. Since the heterogeneity of GCSF receptor appeared to prevent the growth of good-quality crystals, the GCSF receptor was fractionated by anion-exchange chromatography. Crystals of the GCSF–fractionated GCSF receptor complex were grown as a new crystal form in 0.2 M ammonium phosphate. This new crystal form diffracted to beyond 3.0 Å resolution and belonged to space group P3121 (or its enantiomorph P3221), with unit-cell parameters a = b = 134.8, c = 105.7 Å. PMID:16511159

Cell-line-specific stimulation of tumor cell aggressiveness by wound healing factors - a central role for STAT3.

PubMed

Ekblad, Lars; Lindgren, Gustaf; Persson, Emma; Kjellén, Elisabeth; Wennerberg, Johan

2013-01-25

Local recurrence is a major factor affecting survival after treatment for head and neck squamous cell carcinoma (HNSCC). It is possible that the normal processes involved in wound healing after surgical removal of a primary tumor can boost the regrowth of residual cancer cells, thereby contributing to the recurrent growth. In this work, we collected human wound fluids and used them to investigate the effect of wound healing factors on HNSCC cell lines in vitro. Wound fluids were collected from thyroidectomized patients diagnosed with benign disease and were included in assays of cell proliferation, migration, cell scattering, and invasion. The involvement of intracellular signaling pathways and membrane receptors were investigated by western blotting and the inclusion of specific inhibitors. One out of four cell lines was greatly stimulated in proliferation, migration, cell scattering, and invasion by the addition of wound fluid as compared with addition of fetal bovine or human serum. These effects were accompanied by a sharp increase in activation of signal transducer and activator of transcription 3 (STAT3). Inhibition of STAT3 activation abolished the wound fluid response, showing that STAT3 plays an important role in the wound healing response. Several of the observed phenotypic changes were epithelial-to-mesenchymal transition (EMT)-like, but the appropriate changes were not seen in any of the EMT markers investigated. The involvement of c-Met or epidermal growth factor receptor family members was excluded, while the interleukin-6 receptor was found to be partly responsible for the activation of STAT3. In conclusion, we found cell-line-specific effects of wound healing factors on HNSCC, setting the stage for therapy development and predictive opportunities.

Regulation of atrial natriuretic peptide clearance receptors in mesangial cells by growth factors.

PubMed

Paul, R V; Wackym, P S; Budisavljevic, M; Everett, E; Norris, J S

1993-08-25

Rat mesangial cells can express both 130-kDa guanylyl cyclase-coupled and 66-kDa non-coupled atrial natriuretic peptide (ANP) receptors (ANPR-A and ANPR-C, respectively). Exposure of mesangial cells, grown in 20% fetal calf serum, to 0.1% serum for 24 h increased total ANP receptor density more than 2-fold (Bmax = 87 versus 37 fmol/mg of cell protein) without changing binding affinity (Kd = 94 versus 88 pM). Radioligand binding and cross-linking studies demonstrated that up-regulation of ANP binding after serum deprivation was entirely due to an increase in ANPR-C, with little or no change in ANPR-A. Inhibition of protein synthesis with cycloheximide blocked up-regulation after serum deprivation. Steady-state ANPR-C mRNA level was increased 15-fold by serum deprivation, as judged by Northern blotting. There was no change in ANPR-A mRNA. Platelet-derived growth factor and phorbol myristate acetate, when added to low serum medium, blocked or reversed the effect of serum deprivation on ANPR-C. We conclude that synthesis and expression of ANPR-C but not ANPR-A is suppressed by serum, platelet-derived growth factor, and phorbol myristate acetate. Suppression of ANPR-C in vivo could contribute to mesangial cell proliferative responses to growth factors.

Neurotrophins Acting Via TRKB Receptors Activate the JAGGED1-NOTCH2 Cell-Cell Communication Pathway to Facilitate Early Ovarian Development

PubMed Central

Dorfman, Mauricio D.; Kerr, Bredford; Garcia-Rudaz, Cecilia; Paredes, Alfonso H.; Dissen, Gregory A.

2011-01-01

Tropomyosin-related kinase (TRK) receptor B (TRKB) mediates the supportive actions of neurotrophin 4/5 and brain-derived neurotrophic factor on early ovarian follicle development. Absence of TRKB receptors reduces granulosa cell (GC) proliferation and delays follicle growth. In the present study, we offer mechanistic insights into this phenomenon. DNA array and quantitative PCR analysis of ovaries from TrkB-null mice revealed that by the end of the first week of postnatal life, Jagged1, Hes1, and Hey2 mRNA abundance is reduced in the absence of TRKB receptors. Although Jagged1 encodes a NOTCH receptor ligand, Hes1 and Hey2 are downstream targets of the JAGGED1-NOTCH2 signaling system. Jagged1 is predominantly expressed in oocytes, and the abundance of JAGGED1 is decreased in TrkB−/− oocytes. Lack of TRKB receptors also resulted in reduced expression of c-Myc, a NOTCH target gene that promotes entry into the cell cycle, but did not alter the expression of genes encoding core regulators of cell-cycle progression. Selective restoration of JAGGED1 synthesis in oocytes of TrkB−/− ovaries via lentiviral-mediated transfer of the Jagged1 gene under the control of the growth differentiation factor 9 (Gdf9) promoter rescued c-Myc expression, GC proliferation, and follicle growth. These results suggest that neurotrophins acting via TRKB receptors facilitate early follicle growth by supporting a JAGGED1-NOTCH2 oocyte-to-GC communication pathway, which promotes GC proliferation via a c-MYC-dependent mechanism. PMID:22028443

Tamoxifen resistance: from cell culture experiments towards novel biomarkers.

PubMed

Nass, Norbert; Kalinski, Thomas

2015-03-01

Tamoxifen is still the most frequently used antiestrogen for the treatment of patients with premenopausal, estrogen receptor positive breast cancer. However, in 20-30% of these cases, tamoxifen therapy fails due to an existing or developing resistance. The prediction of tamoxifen resistance by appropriate biomarker analysis and the development of novel therapies for tamoxifen resistance in premenopausal breast cancer is, therefore, an important goal of ongoing research. Tamoxifen resistance is associated with altered estrogen receptor expression especially on the plasma membrane, including the alternative G-protein coupled receptor GPR-30 (GPER) and estrogen receptor splice products, such as ERα36. Tamoxifen resistant cells often use alternative pathways to promote proliferation in the absence of genomic estrogen signaling. These pathways involve the epidermal growth factor EGF, the inflammation associated transcription factor NF-κB- and the IGF-1 pathway. Tamoxifen resistant mamma carcinoma cell lines are useful models to understand tamoxifen resistance in-vitro and to search for prognostic or predictive biomarkers. Furthermore, such cell lines can be used to identify potential targets for therapy. Copyright © 2015 Elsevier GmbH. All rights reserved.

The human luteinizing hormone receptor gene promoter: activation by Sp1 and Sp3 and inhibitory regulation.

PubMed

Geng, Y; Tsai-Morris, C H; Zhang, Y; Dufau, M L

1999-09-24

To understand the transcriptional mechanism(s) of human LH receptor (LHR) gene expression, we have identified the dominant functional cis-elements that regulate the activity of the promoter domain (-1 to -176 bp from ATG). Mutagenesis demonstrated that the promoter activity was dependent on two Sp1 domains (-79 bp, -120 bp) in a transformed normal placental cell (PLC) and the choriocarcinoma JAR cell. Both elements interacted with endogenous Sp1 and Sp3 factors but not with Sp2 or Sp4. In Drosophila SL2 cells, the promoter was activated by either Sp1 or Sp3. An ERE half-site (EREhs) at -174 bp was inhibitory (by 100%), but was unresponsive to estradiol and did not bind the estrogen receptor or orphan receptors ERR1 and SF-1. The 5' upstream sequence (-177 to -2056 bp) inhibited promoter activity in PLC by 60%, but only minimally in JAR cells. Activation of the human LHR promoter through Sp1/3 factors is negatively regulated through EREhs and upstream sequences to exert control of gene expression. Copyright 1999 Academic Press.

Supplementation of conventional freezing medium with a combination of catalase and trehalose results in better protection of surface molecules and functionality of hematopoietic cells.

PubMed

Sasnoor, Lalita M; Kale, Vaijayanti P; Limaye, Lalita S

2003-10-01

Our previous studies had shown that a combination of the bio-antioxidant catalase and the membrane stabilizer trehalose in the conventional freezing mixture affords better cryoprotection to hematopoietic cells as judged by clonogenic assays. In the present investigation, we extended these studies using several parameters like responsiveness to growth factors, expression of growth factor receptors, adhesion assays, adhesion molecule expression, and long-term culture-forming ability. Cells were frozen with (test cells) or without additives (control cells) in the conventional medium containing 10% dimethylsulfoxide (DMSO). Experiments were done on mononuclear cells (MNC) from cord blood/fetal liver hematopoietic cells (CB/FL) and CD34(+) cells isolated from frozen MNC. Our results showed that the responsiveness of test cells to the two early-acting cytokines, viz. interleukin-3 (IL-3) and stem cell factor (SCF) in CFU assays was better than control cells as seen by higher colony formation at limiting concentrations of these cytokines. We, therefore, analyzed the expression of these two growth factor receptors by flow cytometry. We found that in cryopreserved test MNC, as well as CD34(+) cells isolated from them, the expression of both cytokine receptors was two- to three-fold higher than control MNC and CD34(+) cells isolated from them. Adhesion assays carried out with CB/FL-derived CD34(+) cells and KG1a cells showed significantly higher adherence of test cells to M210B4 than respective control cells. Cryopreserved test MNC as well as CD34(+) cells isolated from them showed increased expression of adhesion molecules like CD43, CD44, CD49d, and CD49e. On isolated CD34(+) cells and KG1a cells, there was a two- to three-fold increase in a double-positive population expressing CD34/L-selectin in test cells as compared to control cells. Long-term cultures (LTC) were set up with frozen MNC as well as with CD34(+) cells. Clonogenic cells from LTC were enumerated at the end of the fifth week. There was a significantly increased formation of CFU from test cells than from control cells, indicating better preservation of early progenitors in test cells. Our results suggest that use of a combination of catalase and trehalose as a supplement in the conventional freezing medium results in better protection of growth factor receptors, adhesion molecules, and functionality of hematopoietic cells, yielding a better graft quality.

Emodin suppresses maintenance of stemness by augmenting proteosomal degradation of epidermal growth factor receptor/epidermal growth factor receptor variant III in glioma stem cells.

PubMed

Kim, Jeongyub; Lee, Jong-Seon; Jung, Jieun; Lim, Inhye; Lee, Ji-Yun; Park, Myung-Jin

2015-02-01

There is a growing body of evidence that small subpopulations of cells with stem cell-like characteristics within most solid tumors are responsible for the malignancy of aggressive cancer cells and that targeting these cells might be a good therapeutic strategy to reduce the risk of tumor relapse after therapy. Here, we examined the effects of emodin (1,3,8-trihydroxy-6-methylanthraquinone), an active component of the root and rhizome of Rheum palmatum that has several biological activities, including antitumor effects, on primary cultured glioma stem cells (GSCs). Emodin inhibited the self-renewal activity of GSCs in vitro as evidenced by neurosphere formation, limiting dilution, and soft agar clonogenic assays. Emodin inhibited the maintenance of stemness by suppressing the expression of Notch intracellular domain, nonphosphorylated β-catenin, and phosphorylated STAT3 proteins. In addition, treatment with emodin partially induced apoptosis, reduced cell invasiveness, and sensitized GSCs to ionizing radiation. Intriguingly, emodin induced proteosomal degradation of epidermal growth factor receptor (EGFR)/EGFR variant III (EGFRvIII) by interfering with the association of EGFR/EGFRvIII with heat shock protein 90, resulting in the suppression of stemness pathways. Based on these data, we propose that emodin could be considered as a potent therapeutic adjuvant that targets GSCs.

Role of G protein-coupled estrogen receptor-1, matrix metalloproteinases 2 and 9, and heparin binding epidermal growth factor-like growth factor in estradiol-17β-stimulated bovine satellite cell proliferation.

PubMed

Kamanga-Sollo, E; Thornton, K J; White, M E; Dayton, W R

2014-10-01

In feedlot steers, estradiol-17β (E2) and combined E2 and trenbolone acetate (a testosterone analog) implants enhance rate and efficiency of muscle growth; and, consequently, these compounds are widely used as growth promoters. Although the positive effects of E2 on rate and efficiency of bovine muscle growth are well established, the mechanisms involved in these effects are not well understood. Combined E2 and trenbolone acetate implants result in significantly increased muscle satellite cell number in feedlot steers. Additionally, E2 treatment stimulates proliferation of cultured bovine satellite cells (BSC). Studies in nonmuscle cells have shown that binding of E2 to G protein-coupled estrogen receptor (GPER)-1 results in activation of matrix metalloproteinases 2 and 9 (MMP2/9) resulting in proteolytic release of heparin binding epidermal growth factor-like growth factor (hbEGF) from the cell surface. Released hbEGF binds to and activates the epidermal growth factor receptor resulting in increased proliferation. To assess if GPER-1, MMP2/9, and/or hbEGF are involved in the mechanism of E2-stimulated BSC proliferation, we have examined the effects of G36 (a specific inhibitor of GPER-1), CRM197 (a specific inhibitor of hbEGF), and MMP-2/MMP-9 Inhibitor II (an inhibitor of MMP2/9 activity) on E2-stimulated BSC proliferation. Inhibition of GPER-1, MMP2/9, or hbEGF suppresses E2-stimulated BSC proliferation (P < 0.001) suggesting that all these are required in order for E2 to stimulate BSC proliferation. These results strongly suggest that E2 may stimulate BSC proliferation by binding to GPER-1 resulting in MMP2/9-catalyzed release of cell membrane-bound hbEGF and subsequent activation of epidermal growth factor receptor by binding of released hbEGF. Copyright © 2014 Elsevier Inc. All rights reserved.

Neer Award 2018: Platelet-derived growth factor receptor α co-expression typifies a subset of platelet-derived growth factor receptor β-positive progenitor cells that contribute to fatty degeneration and fibrosis of the murine rotator cuff.

PubMed

Jensen, Andrew R; Kelley, Benjamin V; Mosich, Gina M; Ariniello, Allison; Eliasberg, Claire D; Vu, Brandon; Shah, Paras; Devana, Sai K; Murray, Iain R; Péault, Bruno; Dar, Ayelet; Petrigliano, Frank A

2018-04-10

After massive tears, rotator cuff muscle often undergoes atrophy, fibrosis, and fatty degeneration. These changes can lead to high surgical failure rates and poor patient outcomes. The identity of the progenitor cells involved in these processes has not been fully elucidated. Platelet-derived growth factor receptor β (PDGFRβ) and platelet-derived growth factor receptor α (PDGFRα) have previously been recognized as markers of cells involved in muscle fibroadipogenesis. We hypothesized that PDGFRα expression identifies a fibroadipogenic subset of PDGFRβ + progenitor cells that contribute to fibroadipogenesis of the rotator cuff. We created massive rotator cuff tears in a transgenic strain of mice that allows PDGFRβ + cells to be tracked via green fluorescent protein (GFP) fluorescence. We then harvested rotator cuff muscle tissues at multiple time points postoperatively and analyzed them for the presence and localization of GFP + PDGFRβ + PDGFRα + cells. We cultured, induced, and treated these cells with the molecular inhibitor CWHM-12 to assess fibrosis inhibition. GFP + PDGFRβ + PDGFRα + cells were present in rotator cuff muscle tissue and, after massive tears, localized to fibrotic and adipogenic tissues. The frequency of PDGFRβ + PDGFRα + cells increased at 5 days after massive cuff tears and decreased to basal levels within 2 weeks. PDGFRβ + PDGFRα + cells were highly adipogenic and significantly more fibrogenic than PDGFRβ + PDGFRα - cells in vitro and localized to adipogenic and fibrotic tissues in vivo. Treatment with CWHM-12 significantly decreased fibrogenesis from PDGFRβ + PDGFRα + cells. PDGFRβ + PDGFRα + cells directly contribute to fibrosis and fatty degeneration after massive rotator cuff tears in the mouse model. In addition, CWHM-12 treatment inhibits fibrogenesis from PDGFRβ + PDGFRα + cells in vitro. Clinically, perioperative PDGFRβ + PDGFRα + cell inhibition may limit rotator cuff tissue degeneration and, ultimately, improve surgical outcomes for massive rotator cuff tears. Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Suppression of transient receptor potential melastatin 4 expression promotes conversion of endothelial cells into fibroblasts via transforming growth factor/activin receptor-like kinase 5 pathway.

PubMed

Echeverría, Cesar; Montorfano, Ignacio; Cabello-Verrugio, Claudio; Armisén, Ricardo; Varela, Diego; Simon, Felipe

2015-05-01

To study whether transient receptor potential melastatin 4 (TRPM4) participates in endothelial fibrosis and to investigate the underlying mechanism. Primary human endothelial cells were used and pharmacological and short interfering RNA-based approaches were used to test the transforming growth factor beta (TGF-β)/activin receptor-like kinase 5 (ALK5) pathway participation and contribution of TRPM7 ion channel. Suppression of TRPM4 expression leads to decreased endothelial protein expression and increased expression of fibrotic and extracellular matrix markers. Furthermore, TRPM4 downregulation increases intracellular Ca levels as a potential condition for fibrosis. The underlying mechanism of endothelial fibrosis shows that inhibition of TRPM4 expression induces TGF-β1 and TGF-β2 expression, which act through their receptor, ALK5, and the nuclear translocation of the profibrotic transcription factor smad4. TRPM4 acts to maintain endothelial features and its loss promotes fibrotic conversion via TGF-β production. The regulation of TRPM4 levels could be a target for preserving endothelial function during inflammatory diseases.

An introduction to the molecular basics of aryl hydrocarbon receptor biology.

PubMed

Abel, Josef; Haarmann-Stemmann, Thomas

2010-11-01

Depending on their chemical structure and properties, environmental chemicals and other xenobiotics that enter the cell can affect cellular function by either nonselective binding to cellular macromolecules or by interference with cellular receptors, which would initiate a more defined cell biological response. One of these intracellular chemosensor molecules is the aryl hydrocarbon receptor (AhR), a transcription factor of the bHLH/PAS family that is known to mediate the biochemical and toxic effects of dioxins, polyaromatic hydrocarbons and related compounds. Numerous investigations have revealed that the AhR is not only a master regulator of drug metabolism activated by anthropogenic chemicals, but is also triggered by natural and endogenous ligands and can influence cell biological endpoints such as growth and differentiation. Cutting-edge research has identified new intriguing functions of the AhR, such as during proteasomal degradation of steroid hormone receptors, the cellular UVB stress response and the differentiation of certain T-cell subsets. In this review we provide both a survey of the fundamental basics of AhR biology and an insight into new functional aspects of AhR signaling to further stimulate research on this intriguing transcription factor at the interface between toxicology, cell biology and immunology.

CSF-1 Receptor Signaling in Myeloid Cells

PubMed Central

Stanley, E. Richard; Chitu, Violeta

2014-01-01

The CSF-1 receptor (CSF-1R) is activated by the homodimeric growth factors colony-stimulating factor-1 (CSF-1) and interleukin-34 (IL-34). It plays important roles in development and in innate immunity by regulating the development of most tissue macrophages and osteoclasts, of Langerhans cells of the skin, of Paneth cells of the small intestine, and of brain microglia. It also regulates the differentiation of neural progenitor cells and controls functions of oocytes and trophoblastic cells in the female reproductive tract. Owing to this broad tissue expression pattern, it plays a central role in neoplastic, inflammatory, and neurological diseases. In this review we summarize the evolution, structure, and regulation of expression of the CSF-1R gene. We review, the structures of CSF-1, IL-34, and the CSF-1R and the mechanism of ligand binding to and activation of the receptor. We further describe the pathways regulating macrophage survival, proliferation, differentiation, and chemotaxis downstream from the CSF-1R. PMID:24890514

The Plasma Concentration of the B Cell Activating Factor Is Increased in Children With Acute Malaria

PubMed Central

Nduati, Eunice; Gwela, Agnes; Karanja, Henry; Mugyenyi, Cleopatra; Langhorne, Jean; Marsh, Kevin

2011-01-01

Malaria-specific antibody responses in children often appear to be short-lived but the mechanisms underlying this phenomenon are not well understood. In this study, we investigated the relationship between the B-cell activating factor (BAFF) and its receptors expressed on B cells with antibody responses during and after acute malaria in children. Our results demonstrate that BAFF plasma levels increased during acute malarial disease and reflected disease severity. The expression profiles for BAFF receptors on B cells agreed with rapid activation and differentiation of a proportion of B cells to plasma cells. However, BAFF receptor (BAFF-R) expression was reduced on all peripheral blood B cells during acute infection, but those children with the highest level of BAFF-R expression on B cells maintained schizont-specific immunoglobin G (IgG) over a period of 4 months, indicating that dysregulation of BAFF-R expression on B cells may contribute to short-lived antibody responses to malarial antigens in children. In summary, this study suggests a potential role for BAFF during malaria disease, both as a marker for disease severity and in shaping the differentiation pattern of antigen-specific B cells. PMID:21849293

Involvement of the orphan nuclear estrogen receptor-related receptor α in osteoclast adhesion and transmigration

PubMed Central

Bonnelye, Edith; Saltel, Frédéric; Chabadel, Anne; Zirngibl, Ralph A; Aubin, Jane E; Jurdic, Pierre

2010-01-01

The orphan nuclear receptor, estrogen receptor-related receptor α (ERRα) is expressed in osteoblasts and osteoclasts (OCs) and has been proposed to be a modulator of estrogen signaling. To determine the role of ERRα in OC biology, we knocked down ERRα activity by transient transfection of an siRNA directed against ERRα in the RAW264.7 monocyte–macrophage cell line that differentiates into OCs in the presence of receptor activator of nuclear factor κB-ligands and macrophage colony-stimulating factor. In parallel, stable RAW cell lines expressing a dominant-negative form of ERRα and green fluorescent protein (RAW-GFP-ERRαΔAF2) were used. Expression of OC markers was assessed by real-time PCR, and adhesion and transmigration tests were performed. Actin cytoskeletal organization was visualized using confocal microscopy. We found that RAW264.7 cells expressing siRNA directed against ERRα and RAW-GFP-ERRαΔAF2 OCs displayed abnormal spreading, and decreased osteopontin and β3 integrin subunit expression compared with the corresponding control cells. Decreased adhesion and the absence of podosome belts concomitant with abnormal localization of c-src were also observed in RAW-GFP-ERRαΔAF2-derived OCs. In addition, RAW-GFP-ERRαΔAF2-derived OCs failed to transmigrate through osteoblast cell layers. Our data show that the impairment of ERRα function does not alter OC precursor proliferation and differentiation but does alter the adhesion/spreading and migration capacities of mature OCs. PMID:20841427

Variable Dependence of Signaling Output on Agonist Occupancy of Ste2p, a G Protein-coupled Receptor in Yeast.

PubMed

Sridharan, Rajashri; Connelly, Sara M; Naider, Fred; Dumont, Mark E

2016-11-11

We report here on the relationship between ligand binding and signaling responses in the yeast pheromone response pathway, a well characterized G protein-coupled receptor system. Responses to agonist (α-factor) by cells expressing widely varying numbers of receptors depend primarily on fractional occupancy, not the absolute number of agonist-bound receptors. Furthermore, the concentration of competitive antagonist required to inhibit α-factor-dependent signaling is more than 10-fold higher than predicted based on the known ligand affinities. Thus, responses to a particular number of agonist-bound receptors can vary greatly, depending on whether there are unoccupied or antagonist-bound receptors present on the same cell surface. This behavior does not appear to be due to pre-coupling of receptors to G protein or to the Sst2p regulator of G protein signaling. The results are consistent with a signaling response that is determined by the integration of positive signals from agonist-occupied receptors and inhibitory signals from unoccupied receptors, where the inhibitory signals can be diminished by antagonist binding. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Aeromonas salmonicida Infection Only Moderately Regulates Expression of Factors Contributing to Toll-Like Receptor Signaling but Massively Activates the Cellular and Humoral Branches of Innate Immunity in Rainbow Trout (Oncorhynchus mykiss)

PubMed Central

Brietzke, Andreas; Korytář, Tomáš; Jaros, Joanna; Köllner, Bernd; Goldammer, Tom; Seyfert, Hans-Martin; Rebl, Alexander

2015-01-01

Toll-like receptors (TLRs) are known to detect a defined spectrum of microbial structures. However, the knowledge about the specificity of teleost Tlr factors for distinct pathogens is limited so far. We measured baseline expression profiles of 18 tlr genes and associated signaling factors in four immune-relevant tissues of rainbow trout Oncorhynchus mykiss. Intraperitoneal injection of a lethal dose of Aeromonas salmonicida subsp. salmonicida induced highly increased levels of cytokine mRNAs during a 72-hour postinfection (hpi) period. In contrast, only the fish-specific tlr22a2 and the downstream factor irak1 featured clearly increased transcript levels, while the mRNA concentrations of many other tlr genes decreased. Flow cytometry quantified cell trafficking after infection indicating a dramatic influx of myeloid cells into the peritoneum and a belated low level immigration of lymphoid cells. T and B lymphocytes were differentiated with RT-qPCR revealing that B lymphocytes emigrated from and T lymphocytes immigrated into head kidney. In conclusion, no specific TLR can be singled out as a dominant receptor for A. salmonicida. The recruitment of cellular factors of innate immunity rather than induced expression of pathogen receptors is hence of key importance for mounting a first immune defense against invading A. salmonicida. PMID:26266270

Smad7 Regulates the Adult Neural Stem/Progenitor Cell Pool in a Transforming Growth Factor β- and Bone Morphogenetic Protein-Independent Manner▿

PubMed Central

Krampert, Monika; Chirasani, Sridhar Reddy; Wachs, Frank-Peter; Aigner, Robert; Bogdahn, Ulrich; Yingling, Jonathan M.; Heldin, Carl-Henrik; Aigner, Ludwig; Heuchel, Rainer

2010-01-01

Members of the transforming growth factor β (TGF-β) family of proteins modulate the proliferation, differentiation, and survival of many different cell types. Neural stem and progenitor cells (NPCs) in the adult brain are inhibited in their proliferation by TGF-β and by bone morphogenetic proteins (BMPs). Here, we investigated neurogenesis in a hypomorphic mouse model for the TGF-β and BMP inhibitor Smad7, with the hypothesis that NPC proliferation might be reduced due to increased TGF-β and BMP signaling. Unexpectedly, we found enhanced NPC proliferation as well as an increased number of label-retaining cells in vivo. The enhanced proliferation potential of mutant cells was retained in vitro in neurosphere cultures. We observed a higher sphere-forming capacity as well as faster growth and cell cycle progression. Use of specific inhibitors revealed that these effects were independent of TGF-β and BMP signaling. The enhanced proliferation might be at least partially mediated by elevated signaling via epidermal growth factor (EGF) receptor, as mutant cells showed higher expression and activation levels of the EGF receptor. Conversely, an EGF receptor inhibitor reduced the proliferation of these cells. Our data indicate that endogenous Smad7 regulates neural stem/progenitor cell proliferation in a TGF-β- and BMP-independent manner. PMID:20479122

Chronic hypoxia up-regulates expression of adenosine A1 receptors in DDT1-MF2 cells.

PubMed

Hammond, Lucy C; Bonnet, Claire; Kemp, Paul J; Yates, Michael S; Bowmer, Christopher J

2004-02-01

As the first step to understand how chronic hypoxia might regulate smooth muscle function in health and disease, we have employed an established immortalised cell model of smooth muscle, DDT1-MF2 cells, to address the hypothesis that adenosine A1 receptor density is modulated by O2 availability. Maximal specific binding (Bmax) of the selective adenosine A1 receptor antagonist, [3H]-DPCPX, to cell membranes increased 3.5-fold from 0.48 +/- 0.02 pmol/mg to 1.7 +/- 0.5 pmol/mg protein after 16 hr of hypoxia and this effect was not accompanied by any statistically significant changes in either binding affinity (0.84 +/- 0.2 nM vs. 1.2 +/- 0.3 nM) or Hill coefficient (1.1 +/- 0.1 vs. 0.99 +/- 0.03). Hypoxia-evoked increases in membrane receptor density were paralleled in intact DDT1-MF2 cells. In addition, the increase in [3H]-DPCPX binding to intact cells was inhibited by co-incubation during hypoxia with the translational inhibitor cycloheximide, the transcriptional blocker actinomycin D and the NFkappaB inhibitor sulphasalazine. Together, these data show that adenosine A1 receptor density is modulated, at least in part, by O2-dependent activation of the transcription factor NFkappaB and adds to the list of processes dynamically regulated by ambient oxygen availability. Since hypoxia is an initiating factor in acute renal failure, similar changes in transcription may account for up-regulation of adenosine A1 receptors noted previously in the renal vasculature of rats with acute renal failure.

New Strategies in Engineering T-cell Receptor Gene-Modified T cells to More Effectively Target Malignancies.

PubMed

Schmitt, Thomas M; Stromnes, Ingunn M; Chapuis, Aude G; Greenberg, Philip D

2015-12-01

The immune system, T cells in particular, have the ability to target and destroy malignant cells. However, antitumor immune responses induced from the endogenous T-cell repertoire are often insufficient for the eradication of established tumors, as illustrated by the failure of cancer vaccination strategies or checkpoint blockade for most tumors. Genetic modification of T cells to express a defined T-cell receptor (TCR) can provide the means to rapidly generate large numbers of tumor-reactive T cells capable of targeting tumor cells in vivo. However, cell-intrinsic factors as well as immunosuppressive factors in the tumor microenvironment can limit the function of such gene-modified T cells. New strategies currently being developed are refining and enhancing this approach, resulting in cellular therapies that more effectively target tumors and that are less susceptible to tumor immune evasion. ©2015 American Association for Cancer Research.

Transforming growth factor-{alpha} enhances corneal epithelial cell migration by promoting EGFR recycling.

PubMed

McClintock, Jennifer L; Ceresa, Brian P

2010-07-01

PURPOSE. The goal of this study was to determine the molecular mechanism by which transforming growth factor-alpha (TGF-alpha) is a more potent activator of epidermal growth factor receptor (EGFR)-mediated corneal wound healing than epidermal growth factor (EGF). METHODS. Telomerase immortalized human corneal epithelial (hTCEpi) cells and primary human corneal epithelial cells were tested for their ability to migrate in response to EGF and TGF-alpha. In parallel, the endocytic trafficking of the EGFR in response to these same ligands was examined using indirect immunofluorescence, immunoblots, and radioligand binding. RESULTS. TGF-alpha, compared with EGF, is a more potent activator of corneal epithelial cell migration. Although both TGF-alpha and EGF were able to induce EGFR internalization and phosphorylation, only those receptors that were stimulated with EGF progressed to lysosomal degradation. EGFRs stimulated with TGF-alpha recycled back to the plasma membrane, where they could be reactivated with ligand. CONCLUSIONS. This study reveals that EGFR-mediated cell migration is limited by ligand-stimulated downregulation of the EGFR. This limitation can be overcome by treating cells with TGF-alpha because TGF-alpha stimulates EGFR endocytosis, but not degradation. After internalization of the TGF-alpha/EGFR complex, EGFR recycles back to the plasma membrane, where it can be restimulated. This sequence of events provides the receptor multiple opportunities for stimulation. Thus, stimulation with TGF-alpha prolongs EGFR signaling compared with EGF.

Thalidomide inhibits lipopolysaccharide-induced tumor necrosis factor-alpha production via down-regulation of MyD88 expression.

PubMed

Noman, Abu Shadat M; Koide, Naoki; Hassan, Ferdaus; I-E-Khuda, Imtiaz; Dagvadorj, Jargalsaikhan; Tumurkhuu, Gantsetseg; Islam, Shamima; Naiki, Yoshikazu; Yoshida, Tomoaki; Yokochi, Takashi

2009-02-01

The effect of thalidomide on lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-alpha production was studied by using RAW 264.7 murine macrophage-like cells. Thalidomide significantly inhibited LPS-induced TNF-alpha production. Thalidomide prevented the activation of nuclear factor (NF)-KB by down-regulating phosphorylation of inhibitory KB factor (IKB), and IKB kinase (IKK)-alpha and IKK-beta Moreover, thalidomide inhibited LPS-induced phosphorylation of AKT, p38 and stress-activated protein kinase (SAPK)/JNK. The expression of myeloid differentiation factor 88 (MyD88) protein and mRNA was markedly reduced in thalidomide-treated RAW 264.7 cells but there was no significant alteration in the expression of interleukin-1 receptor-associated kinase (IRAK) 1 and TNF receptor-associated factor (TRAF) 6 in the cells. Thalidomide did not affect the cell surface expression of Toll-like receptor (TLR) 4 and CD14, suggesting the impairment of intracellular LPS signalling in thalidomide-treated RAW 264.7 cells. Thalidomide significantly inhibited the TNF-alpha production in response to palmitoyl-Cys(RS)-2,3-di(palmitoyloxy) propyl)-Ala-Gly-OH (Pam(3)Cys) as a MyD88-dependent TLR2 ligand. Therefore, it is suggested that thalidomide might impair LPS signalling via down-regulation of MyD88 protein and mRNA and inhibit LPS-induced TNF-alpha production. The putative mechanism of thalidomide-induced MyD88 down-regulation is discussed.

Interactions of phosphatidylinositol kinase, GTPase-activating protein (GAP), and GAP-associated proteins with the colony-stimulating factor 1 receptor.

PubMed Central

Reedijk, M; Liu, X Q; Pawson, T

1990-01-01

The interactions of the macrophage colony-stimulating factor 1 (CSF-1) receptor with potential targets were investigated after ligand stimulation either of mouse macrophages or of fibroblasts that ectopically express mouse CSF-1 receptors. In Rat-2 cells expressing the mouse CSF-1 receptor, full activation of the receptor and cellular transformation require exogenous CSF-1, whereas NIH 3T3 cells expressing mouse c-fms are transformed by autocrine stimulation. Activated CSF-1 receptors physically associate with a phosphatidylinositol (PI) 3'-kinase. A mutant CSF-1 receptor with a deletion of the kinase insert region was deficient in its ability to bind functional PI 3'-kinase and to induce PI 3'-kinase activity precipitable with antiphosphotyrosine antibodies. In fibroblasts, CSF-1 stimulation also induced the phosphorylation of the GTPase-activating protein (GAP)-associated protein p62 on tyrosine, although GAP itself was a relatively poor substrate. In contrast to PI 3'-kinase association, phosphorylation of p62 and GAP was not markedly affected by deletion of the kinase insert region. These results indicate that the kinase insert region selectively enhances the CSF-1-dependent association of the CSF-1 receptor with active PI 3'-kinase. The insert deletion mutant retains considerable transforming activity in NIH 3T3 cells (G. Taylor, M. Reedijk, V. Rothwell, L. Rohrschneider, and T. Pawson, EMBO J. 8:2029-2037, 1989). This mutant was more seriously impaired in Rat-2 cell transformation, although mutant-expressing Rat-2 cells still formed small colonies in soft agar in the presence of CSF-1. Therefore, phosphorylation of GAP and p62 through activation of the CSF-1 receptor does not result in full fibroblast transformation. The interaction between the CSF-1 receptor and PI 3'-kinase may contribute to c-fms fibroblast transformation and play a role in CSF-1-stimulated macrophages. Images PMID:2172781

G protein-coupled receptor 30 down-regulates cofactor expression and interferes with the transcriptional activity of glucocorticoid.

PubMed

Ylikomi, Timo; Vienonen, Annika; Ahola, Tytti M

2004-11-01

G protein-coupled receptor 30 (GPR30) has previously been described to be important in steroid-mediated growth and to inhibit cell proliferation. Here we investigated whether the effect of GPR30 on cell growth is dependent on steroid hormone receptors. We stably introduced GPR30 in immortalized normal mammary epithelial (HME) cells using retroviruses for gene delivery. GPR30 inhibited the growth and proliferation of the cells. They expressed glucocorticoid receptor, but not estrogen or progesterone receptor. GPR30 down-regulated the expression of cofactor transcription intermediary factor 2 (TIF2) analyzed using quantitative RT-PCR analysis, and also diminished the expression of TIF2 at protein level analyzed by Western blotting using nuclear extracts from mammary epithelial cells. When HME cells were transiently transfected with the glucocorticoid response element MMTV-luc reporter plasmid, stable expression of GPR30 resulted in the abolition of ligand-induced transactivation of the promoter. In COS cells, transient transfection of GPR30 with glucocorticoid receptor alpha resulted in an abrogation of the MMTV-luc and GRE-luc reporter activities induced by dexamethasone. The results suggest a novel mechanism by which membrane-initiated signaling interferes with steroid signaling.

Cellular density-dependent down-regulation of EP4 prostanoid receptors via the up-regulation of hypoxia-inducible factor-1α in HCA-7 human colon cancer cells.

PubMed

Otake, Sho; Yoshida, Kenji; Seira, Naofumi; Sanchez, Christopher M; Regan, John W; Fujino, Hiromichi; Murayama, Toshihiko

2015-02-01

Increases in prostaglandin E2 (PGE2) and cyclooxygenase-2 (COX-2) levels are features of colon cancer. Among the different E-type prostanoid receptor subtypes, EP4 receptors are considered to play a crucial role in carcinogenesis by, for example, inducing COX-2 when stimulated with PGE2. However, EP4 receptor levels and PGE2-induced cellular responses are inconsistent among the cellular conditions. Therefore, the connections responsible for the expression of EP4 receptors were investigated in the present study by focusing on cell density-induced hypoxia-inducible factor-1α (HIF-1α). The expression of EP4 receptors was examined using immunoblot analysis, quantitative polymerase chain reaction, and reporter gene assays in HCA-7 human colon cancer cells with different cellular densities. The involvement of HIF-1α and its signaling pathways were also examined by immunoblot analysis, reporter gene assays, and with siRNA. We here demonstrated that EP4 receptors as well as EP4 receptor-mediated COX-2 expression levels decreased with an increase in cellular density. In contrast, HIF-1α levels increased in a cellular density-dependent manner. The knockdown of HIF-1α by siRNA restored the expression of EP4 receptors and EP4 receptor-mediated COX-2 in cells at a high density. Thus, the cellular density-dependent increase observed in HIF-1α expression levels reduced the expression of COX-2 by decreasing EP4 receptor levels. This novel regulation mechanism for the expression of EP4 receptors by HIF-1α may provide an explanation for the inconsistent actions of PGE2. The expression levels of EP4 receptors may vary depending on cellular density, which may lead to the differential activation of their signaling pathways by PGE2. Thus, cellular density-dependent PGE2-mediated signaling may determine the fate/stage of cancer cells, i.e., the surrounding environments could define the fate/stage of malignancies associated with colon cancer.

Cellular density-dependent down-regulation of EP4 prostanoid receptors via the up-regulation of hypoxia-inducible factor-1α in HCA-7 human colon cancer cells

PubMed Central

Otake, Sho; Yoshida, Kenji; Seira, Naofumi; Sanchez, Christopher M; Regan, John W; Fujino, Hiromichi; Murayama, Toshihiko

2015-01-01

Increases in prostaglandin E2 (PGE2) and cyclooxygenase-2 (COX-2) levels are features of colon cancer. Among the different E-type prostanoid receptor subtypes, EP4 receptors are considered to play a crucial role in carcinogenesis by, for example, inducing COX-2 when stimulated with PGE2. However, EP4 receptor levels and PGE2-induced cellular responses are inconsistent among the cellular conditions. Therefore, the connections responsible for the expression of EP4 receptors were investigated in the present study by focusing on cell density-induced hypoxia-inducible factor-1α (HIF-1α). The expression of EP4 receptors was examined using immunoblot analysis, quantitative polymerase chain reaction, and reporter gene assays in HCA-7 human colon cancer cells with different cellular densities. The involvement of HIF-1α and its signaling pathways were also examined by immunoblot analysis, reporter gene assays, and with siRNA. We here demonstrated that EP4 receptors as well as EP4 receptor-mediated COX-2 expression levels decreased with an increase in cellular density. In contrast, HIF-1α levels increased in a cellular density-dependent manner. The knockdown of HIF-1α by siRNA restored the expression of EP4 receptors and EP4 receptor-mediated COX-2 in cells at a high density. Thus, the cellular density-dependent increase observed in HIF-1α expression levels reduced the expression of COX-2 by decreasing EP4 receptor levels. This novel regulation mechanism for the expression of EP4 receptors by HIF-1α may provide an explanation for the inconsistent actions of PGE2. The expression levels of EP4 receptors may vary depending on cellular density, which may lead to the differential activation of their signaling pathways by PGE2. Thus, cellular density-dependent PGE2-mediated signaling may determine the fate/stage of cancer cells, i.e., the surrounding environments could define the fate/stage of malignancies associated with colon cancer. PMID:25692008

A high speed multifocal multiphoton fluorescence lifetime imaging microscope for live-cell FRET imaging

PubMed Central

Poland, Simon P.; Krstajić, Nikola; Monypenny, James; Coelho, Simao; Tyndall, David; Walker, Richard J.; Devauges, Viviane; Richardson, Justin; Dutton, Neale; Barber, Paul; Li, David Day-Uei; Suhling, Klaus; Ng, Tony; Henderson, Robert K.; Ameer-Beg, Simon M.

2015-01-01

We demonstrate diffraction limited multiphoton imaging in a massively parallel, fully addressable time-resolved multi-beam multiphoton microscope capable of producing fluorescence lifetime images with sub-50ps temporal resolution. This imaging platform offers a significant improvement in acquisition speed over single-beam laser scanning FLIM by a factor of 64 without compromising in either the temporal or spatial resolutions of the system. We demonstrate FLIM acquisition at 500 ms with live cells expressing green fluorescent protein. The applicability of the technique to imaging protein-protein interactions in live cells is exemplified by observation of time-dependent FRET between the epidermal growth factor receptor (EGFR) and the adapter protein Grb2 following stimulation with the receptor ligand. Furthermore, ligand-dependent association of HER2-HER3 receptor tyrosine kinases was observed on a similar timescale and involved the internalisation and accumulation or receptor heterodimers within endosomes. These data demonstrate the broad applicability of this novel FLIM technique to the spatio-temporal dynamics of protein-protein interaction. PMID:25780724

An endogenous 55 kDa TNF receptor mediates cell death in a neural cell line.

PubMed

Sipe, K J; Srisawasdi, D; Dantzer, R; Kelley, K W; Weyhenmeyer, J A

1996-06-01

Tumor necrosis factor-alpha (TNF) is associated with developmental and injury-related events in the central nervous system (CNS). In the present study, we have examined the role of TNF on neurons using the clonal murine neuroblastoma line, N1E-115 (N1E). N1E cells represent a well-defined model for studying neuronal development since they can be maintained as either undifferentiated, mitotically active neuroblasts or as differentiated, mature neurons. Northern and reverse transcription-polymerase chain reaction (RT-PCR) analyses revealed that both undifferentiated and differentiated N1Es express transcripts for the 55 kDa TNF receptor (TNFR), but not the 75 kDa TNFR. The biological activity of the expressed TNF receptor was demonstrated by a dose dependent cytotoxicity to either recombinant murine or human TNF when the cells were incubated with the transcriptional inhibitor actinomycin D. The lack of the 75 kDa receptor mRNA expression and the dose dependent response to rHuTNF, an agonist specific for the murine 55 kDa receptor, suggest that the TNF induced cytotoxicity is mediated through the 55 kDa receptor in both the undifferentiated and differentiated N1Es. Light microscopic observations, flow cytometric analysis of hypodiploid DNA, and electrophoretic analysis of nucleosomal DNA fragmentation of N1Es treated with actinomycin D and TNF revealed features characteristic of both necrotic and apoptotic cell death. These findings demonstrate that blast and mature N1E cells express the 55 kDa TNF receptor which is responsible for inducing both necrotic and apoptotic death in these cells. The observation that actinomycin D renders N1E cells susceptible to the cytotoxic effects of TNF indicates that a sensitization step, such as removal of an endogenous protective factor or viral-mediated inhibition of transcription, may be necessary for TNF cytotoxicity in neurons.

Role of T-cell-specific nuclear factor κB in islet allograft rejection.

PubMed

Porras, Delia Lozano; Wang, Ying; Zhou, Ping; Molinero, Luciana L; Alegre, Maria-Luisa

2012-05-27

Pancreatic islet transplantation has the potential to cure type 1 diabetes, a chronic lifelong disease, but its clinical applicability is limited by allograft rejection. Nuclear factor κB (NF-κB) is a transcription factor important for survival and differentiation of T cells. In this study, we tested whether NF-κB in T cells is required for the rejection of islet allografts. Mice expressing a superrepressor form of NF-κB selectively in T cells (IκBαΔN-Tg mice) with or without the antiapoptotic factor Bcl-xL, or mice with impaired T-cell receptor (TCR)- and B cell receptor-driven NF-κB activity (CARMA1-KO mice) were rendered diabetic and transplanted with islet allografts. Secondary skin transplantation in long-term acceptors of islet allografts was used to test for the development of donor-specific tolerance. Immune infiltration of the transplanted islets was examined by immunofluorescence. TCR-transgenic CD4 T cells were used to follow T-cell priming and differentiation. Islet allograft survival was prolonged in IκBαΔN-Tg mice, although the animals did not develop donor-specific tolerance. Reduced NF-κB activity did not prevent T-cell priming or differentiation but reduced survival of activated T cells, as transgenic expression of Bcl-xL restored islet allograft rejection in IκBαΔN-Tg mice. Abolishing TCR- and B cell receptor-driven activation of NF-κB selectively by CARMA1 deficiency prevented T-cell priming and islet allograft rejection. Our data suggest that T cell-NF-κB plays an important role in the rejection of islet allografts. Targeting NF-κB selectively in lymphocytes seems a promising approach to facilitate acceptance of transplanted islets.

Targeting the fibroblast growth factor receptors for the treatment of cancer.

PubMed

Lemieux, Steven M; Hadden, M Kyle

2013-06-01

Receptor tyrosine kinases (RTKs) are transmembrane proteins that play a critical role in stimulating signal transduction cascades to influence cell proliferation, growth, and differentiation and they have also been shown to promote angiogenesis when they are up-regulated or mutated. For this reason, their dysfunction has been implicated in the development of human cancer. Over the past decade, much attention has been devoted to developing inhibitors and antibodies against several classes of RTKs, including vascular endothelial growth factor receptors (VEGFRs), epidermal growth factor receptors (EGFRs), and platelet-derived growth factor receptors (PDGFRs). More recently, interest in the fibroblast growth factor receptor (FGFR) class of RTKs as a drug target for the treatment of cancer has emerged. Signaling through FGFRs is critical for normal cellular function and their dysregulation has been linked to various malignancies such as breast and prostate cancer. This review will focus on the current state of both small molecules and antibodies as FGFR inhibitors to provide insight into their development and future potential as anti-cancer agents.

Human corpus luteum: presence of epidermal growth factor receptors and binding characteristics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ayyagari, R.R.; Khan-Dawood, F.S.

Epidermal growth factor receptors are present in many reproductive tissues but have not been demonstrated in the human corpus luteum. To determine the presence of epidermal growth factor receptors and its binding characteristics, we carried out studies on the plasma cell membrane fraction of seven human corpora lutea (days 16 to 25) of the menstrual cycle. Specific epidermal growth factor receptors were present in human corpus luteum. Insulin, nerve growth factor, and human chorionic gonadotropin did not competitively displace epidermal growth factor binding. The optimal conditions for corpus luteum-epidermal growth factor receptor binding were found to be incubation for 2more » hours at 4 degrees C with 500 micrograms plasma membrane protein and 140 femtomol /sup 125/I-epidermal growth factor per incubate. The number (mean +/- SEM) of epidermal growth factor binding sites was 12.34 +/- 2.99 X 10(-19) mol/micrograms protein; the dissociation constant was 2.26 +/- 0.56 X 10(-9) mol/L; the association constant was 0.59 +/- 0.12 X 10(9) L/mol. In two regressing corpora lutea obtained on days 2 and 3 of the menstrual cycle, there was no detectable specific epidermal growth factor receptor binding activity. Similarly no epidermal growth factor receptor binding activity could be detected in ovarian stromal tissue. Our findings demonstrate that specific receptors for epidermal growth factor are present in the human corpus luteum. The physiologic significance of epidermal growth factor receptors in human corpus luteum is unknown, but epidermal growth factor may be involved in intragonadal regulation of luteal function.« less

Expression of Epidermal Growth Factor Receptor and Transforming Growth Factor Alpha in Cancer Bladder: Schistosomal and Non-Schistosomal

PubMed Central

Badawy, Afkar A.; El-Hindawi, Ali; Hammam, Olfat; Moussa, Mona; Helal, Noha S.; Kamel, Amira

2017-01-01

Introduction Overexpression of epidermal growth factor receptor (EGFR) has been described in several solid tumors including bladder cancer. Transforming growth factor alpha (TGFα) is frequently deregulated in neoplastic cells and plays a role in the development of bladder cancer. TGFα-EGFR ligand-receptor combination constitutes an important event in multistep tumorigenesis. Methods This study was done on 30 bladder biopsies from patients with urothelial carcinoma, 15 with squamous cell carcinoma, 10 with cystitis and 5 normal control bladder specimens. All were immuohistochemically stained with EGFR and TGFα antibodies. Results EGFR and TGFα were over-expressed in higher grades and late stages of bladder cancer. Moreover, they show higher expression in squamous cell carcinoma compared to urothelial carcinoma and in schistosomal associated lesions than in non-schistosomal associated lesions. Conclusion EGFR and TGFα could be used as prognostic predictors in early stage and grade of bladder cancer cases, especially those with schistosomal association. In addition they can help in selecting patients who can get benefit from anti-EGFR molecular targeted therapy. PMID:28413380

Synergistic apoptosis in head and neck squamous cell carcinoma cells by co-inhibition of insulin-like growth factor-1 receptor signaling and compensatory signaling pathways.

PubMed

Axelrod, Mark J; Mendez, Rolando E; Khalil, Ashraf; Leimgruber, Stephanie S; Sharlow, Elizabeth R; Capaldo, Brian; Conaway, Mark; Gioeli, Daniel G; Weber, Michael J; Jameson, Mark J

2015-12-01

In head and neck squamous cell carcinoma (HNSCC), resistance to single-agent targeted therapy may be overcome by co-targeting of compensatory signaling pathways. A targeted drug screen with 120 combinations was used on 9 HNSCC cell lines. Multiple novel drug combinations demonstrated synergistic growth inhibition. Combining the insulin-like growth factor-1 receptor (IGF-1R) inhibitor, BMS754807, with either the human epidermal growth factor receptor (HER)-family inhibitor, BMS599626, or the Src-family kinase inhibitor, dasatinib, resulted in substantial synergy and growth inhibition. Depending on the cell line, these combinations induced synergistic or additive apoptosis; when synergistic apoptosis was observed, AKT phosphorylation was inhibited to a greater extent than either drug alone. Conversely, when additive apoptosis occurred, AKT phosphorylation was not reduced by the drug combination. Combined IGF-1R/HER family and IGF-1R/Src family inhibition may have therapeutic potential in HNSCC. AKT may be a node of convergence between IGF-1R signaling and pathways that compensate for IGF-1R inhibition. © 2015 Wiley Periodicals, Inc.

EFFECT OF GROWTH FACTOR-FIBRONECTIN MATRIX INTERACTION ON RAT TYPE II CELL ADHESION AND DNA SYTHESIS

EPA Science Inventory

ABSTRACT

Type II cells attach, migrate and proliferate on a provisional fibronectin-rich matrix during alveolar wall repair after lung injury. The combination of cell-substratum interactions via integrin receptors and exposure to local growth factors are likely to initiat...

Altered gene products involved in the malignant reprogramming of cancer stem/progenitor cells and multitargeted therapies

PubMed Central

Mimeault, Murielle; Batra, Surinder K.

2013-01-01

Recent studies in the field of cancer stem cells have revealed that the alterations in key gene products involved in the epithelial-mesenchymal transition (EMT) program, altered metabolic pathways such as enhanced glycolysis, lipogenesis and/or autophagy and treatment resistance may occur in cancer stem/progenitor cells and their progenies during cancer progression. Particularly, the sustained activation of diverse developmental cascades such as hedgehog, epidermal growth factor receptor (EGFR), Wnt/β-catenin, Notch, transforming growth factor-β (TGF-β)/TGF-βR receptors and/or stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor 4 (CXCR4) can play critical functions for high self-renewal potential, survival, invasion and metastases of cancer stem/progenitor cells and their progenies. It has also been observed that cancer cells may be reprogrammed to re-express different pluripotency-associated stem cell-like markers such as Myc, Oct-3/4, Nanog and Sox-2 along the EMT process and under stressful and hypoxic conditions. Moreover, the enhanced expression and/or activities of some drug resistance-associated molecules such as Bcl-2, Akt/molecular target of rapamycin (mTOR), nuclear factor-kappaB (NF-κB), hypoxia-inducible factors (HIFs), macrophage inhibitory cytokine-1 (MIC-1) and ATP-binding cassette (ABC) multidrug transporters frequently occur in cancer cells during cancer progression and metastases. These molecular events may cooperate for the survival and acquisition of a more aggressive and migratory behavior by cancer stem/progenitor cells and their progenies during cancer transition to metastatic and recurrent disease states. Of therapeutic interest, these altered gene products may also be exploited as molecular biomarkers and therapeutic targets to develop novel multitargeted strategies for improving current cancer therapies and preventing disease relapse. PMID:23994756

Synergistic interaction of the cannabinoid and death receptor systems - a potential target for future cancer therapies?

PubMed

Keresztes, Attila; Streicher, John M

2017-10-01

Cannabinoid receptors have been shown to interact with other receptors, including tumor necrosis factor receptor superfamily (TNFRS) members, to induce cancer cell death. When cannabinoids and death-inducing ligands (including TNF-related apoptosis-inducing ligand) are administered together, they have been shown to synergize and demonstrate enhanced antitumor activity in vitro. Certain cannabinoid ligands have been shown to sensitize cancer cells and synergistically interact with members of the TNFRS, thus suggesting that the combination of cannabinoids with death receptor (DR) ligands induces additive or synergistic tumor cell death. This review summarizes recent findings on the interaction of the cannabinoid and DR systems and suggests possible clinical co-application of cannabinoids and DR ligands in the treatment of various malignancies. © 2017 Federation of European Biochemical Societies.

Receptor-selective retinoids implicate retinoic acid receptor alpha and gamma in the regulation of bmp-2 and bmp-4 in F9 embryonal carcinoma cells.

PubMed

Rogers, M B

1996-01-01

The effect of retinoids on malignant cells and embryos indicates that retinoids influence the expression of growth factors or alter the response of cells to growth factors. The bone morphogenetic proteins, Bmp-2 and Bmp-4, are candidates for such growth factors because retinoic acid (RA) treatment of F9 embryonal carcinoma cells induced Bmp-2 mRNA, while simultaneously repressing Bmp-4 levels. Also, recombinant Bmp-2 affected the growth and differentiation of these cells. Regulation of each gene was concentration dependent and required continuous RA treatment. The short half-lives of the Bmp-2 (75 +/- 11 min) and Bmp-4 (70 +/- 4 min) mRNAs suggest that their abundance is primarily controlled at the transcriptional level. To determine which RA receptor (RAR) controls bmp-2 and bmp-4 expression, F9 cells were exposed to various receptor-selective retinoids. RAR alpha- and gamma-selective retinoids induced Bmp-2 and repressed Bmp-4 equally as well as all-trans RA. In contrast, a RAR beta-selective retinoid had little effect on Bmp-2 induction but repressed Bmp-4. A RAR alpha-selective antagonist inhibited all-trans RA stimulation of Bmp-2, although not as dramatically as a RAR beta gamma-selective antagonist. No differences were observed between Bmp levels in all-trans RA and 9-cis RA-treated cells, indicating that the RXRs play little part in controlling these genes. The results are consistent with RAR alpha and gamma-controlled Bmp-2 and Bmp-4 regulation.

Cytotoxic-T-Lymphocyte Antigen 4 Receptor Signaling for Lymphocyte Adhesion Is Mediated by C3G and Rap1

PubMed Central

Kloog, Yoel

2014-01-01

T-lymphocyte adhesion plays a critical role in both inflammatory and autoimmune responses. The small GTPase Rap1 is the key coordinator mediating T-cell adhesion to endothelial cells, antigen-presenting cells, and virus-infected cells. We describe a signaling pathway, downstream of the cytotoxic T-lymphocyte antigen 4 (CTLA-4) receptor, leading to Rap1-mediated adhesion. We identified a role for the Rap1 guanine nucleotide exchange factor C3G in the regulation of T-cell adhesion and showed that this factor is required for both T-cell receptor (TCR)-mediated and CTLA-4-mediated T-cell adhesion. Our data indicated that C3G translocates to the plasma membrane downstream of TCR signaling, where it regulates activation of Rap1. We also showed that CTLA-4 receptor signaling mediates tyrosine phosphorylation in the C3G protein, and that this is required for augmented activation of Rap1 and increased adhesion mediated by leukocyte function-associated antigen type 1 (LFA-1). Zap70 is required for C3G translocation to the plasma membrane, whereas the Src family member Hck facilitates C3G phosphorylation. These findings point to C3G and Hck as promising potential therapeutic targets for the treatment of T-cell-dependent autoimmune disorders. PMID:24396067

3D Tracking of individual growth factor receptors on polarized cells

NASA Astrophysics Data System (ADS)

Werner, James; Stich, Dominik; Cleyrat, Cedric; Phipps, Mary; Wadinger-Ness, Angela; Wilson, Bridget

We have been developing methods for following 3D motion of selected biomolecular species throughout mammalian cells. Our approach exploits a custom designed confocal microscope that uses a unique spatial filter geometry and active feedback 200 times/second to follow fast 3D motion. By exploiting new non-blinking quantum dots as fluorescence labels, individual molecular trajectories can be observed for several minutes. We also will discuss recent instrument upgrades, including the ability to perform spinning disk fluorescence microscopy on the whole mammalian cell performed simultaneously with 3D molecular tracking experiments. These instrument upgrades were used to quantify 3D heterogeneous transport of individual growth factor receptors (EGFR) on live human renal cortical epithelial cells.

Hepatic Stellate Cells Express Functional CXCR4: Role in Stromal Cell–Derived Factor-1α–Mediated Stellate Cell Activation

PubMed Central

Hong, Feng; Tuyama, Ana; Lee, Ting Fang; Loke, Johnny; Agarwal, Ritu; Cheng, Xin; Garg, Anita; Fiel, M. Isabel; Schwartz, Myron; Walewski, Jose; Branch, Andrea; Schecter, Alison D.; Bansal, Meena B.

2010-01-01

Chemokine interactions with their receptors have been implicated in hepatic stellate cell (HSC) activation. The hepatic expression of CXCR4 messenger RNA is increased in hepatitis C cirrhotic livers and plasma levels of its endogenous ligand, stromal cell–derived factor-1α (SDF-1α), correlate with increased fibrosis in these patients. The expression of CXCR4 by HSCs has not been reported. We therefore examined whether HSCs express CXCR4 in vivo and in vitro and explored whether SDF-1α/CXCR4 receptor engagement promotes HSC activation, fibrogenesis, and proliferation. The hepatic protein expression of both CXCR4 and SDF-1α is increased in hepatitis C cirrhotic livers and immunoflourescent and immunohistochemical staining confirms that HSCs express CXCR4 in vivo. Immortalized human stellate cells as well as primary human HSCs express CXCR4, and cell surface receptor expression increases with progressive culture-induced activation. Treatment of stellate cells with recombinant SDF-1α increases expression of α-smooth muscle actin and collagen I and stimulates a dose-dependent increase in HSC proliferation. Inhibitor studies suggest that SDF-1α/CXCR4-dependent extracellular signal-regulated kinase 1/2 and Akt phosphorylation mediate effects on collagen I expression and stellate cell proliferation. Conclusion HSCs express CXCR4 receptor in vivo and in vitro. CXCR4 receptor activation by SDF-1α is profibrogenic through its effects on HSC activation, fibrogenesis, and proliferation. Extracellular signal-regulated kinase 1/2 and phosphoinositide 3-kinase pathways mediate SDF-1α–induced effects on HSC expression of collagen I and proliferation. The availability of small molecule inhibitors of CXCR4 make this receptor an appealing target for antifibrotic approaches. PMID:19434726

Kinin and Purine Signaling Contributes to Neuroblastoma Metastasis.

PubMed

Ulrich, Henning; Ratajczak, Mariusz Z; Schneider, Gabriela; Adinolfi, Elena; Orioli, Elisa; Ferrazoli, Enéas G; Glaser, Talita; Corrêa-Velloso, Juliana; Martins, Poliana C M; Coutinho, Fernanda; Santos, Ana P J; Pillat, Micheli M; Sack, Ulrich; Lameu, Claudiana

2018-01-01

Bone marrow metastasis occurs in approximately 350,000 patients that annually die in the U.S. alone. In view of the importance of tumor cell migration into the bone marrow, we have here investigated effects of various concentrations of stromal cell-derived factor-1 (SDF-1), bradykinin- and ATP on bone marrow metastasis. We show for first time that bradykinin augmented chemotactic responsiveness of neuroblastoma cells to SDF-1 and ATP concentrations, encountered under physiological conditions. Bradykinin upregulated VEGF expression, increased metalloproteinase activity and induced adhesion of neuroblastoma cells. Bradykinin augmented SDF-1-induced intracellular Ca 2+ mobilization as well as resensitization and expression of ATP-sensing P2X7 receptors. Bradykinin treatment resulted in higher gene expression levels of the truncated P2X7B receptor compared to those of the P2X7A full-length isoform. Bradykinin as pro-metastatic factor induced tumor proliferation that was significantly decreased by P2X7 receptor antagonists; however, the peptide did not enhance cell death nor P2X7A receptor-related pore activity, promoting neuroblastoma growth. Furthermore, immunodeficient nude/nude mice transplanted with bradykinin-pretreated neuroblastoma cells revealed significantly higher metastasis rates compared to animals injected with untreated cells. In contrast, animals receiving Brilliant Blue G, a P2X7 receptor antagonist, did not show any specific dissemination of neuroblastoma cells to the bone marrow and liver, and metastasis rates were drastically reduced. Our data suggests correlated actions of kinins and purines in neuroblastoma dissemination, providing novel avenues for clinic research in preventing metastasis.

Expression of receptors for atrial natriuretic peptide on the murine bone marrow-derived stromal cells.

PubMed

Agui, T; Yamada, T; Legros, G; Nakajima, T; Clark, M; Peschel, C; Matsumoto, K

1992-05-01

Atrial natriuretic peptide (ANP) receptors were identified on both murine bone marrow-derived stromal cell lines A-3 and ALC and primary cultured cells using [125I]ANP binding assays and Northern blot analyses. The binding of [125I] ANP to the stromal cells was rapid, saturable, and of high affinity. The dissociation constants between ANP and its receptors on these cells showed no difference among cell types, while maximal binding capacity values were different among cell types. Competitive inhibition of [125I]ANP binding with C-atrial natriuretic factor, specific for ANP clearance receptor (ANPR-C), revealed that most of [125I]ANP-binding sites corresponded to ANPR-C. Northern blotting data corroborated that bone marrow-derived stromal cells expressed ANPR-C. However, in ALC cells, ANP biological receptors (either ANPR-A or ANPR-B), the mol wt of which is approximately 130K, were detected, and cGMP was accumulated after stimulation with ANP. On the other hand, in another stromal cell clone, A-3 cells, the expression of biological receptor was not detected in the affinity cross-linking and competitive inhibition experiments using [125I]ANP. However, A-3 cells accumulated cGMP by responding to ANPR-B-specific ligand, C-type natriuretic peptide. These results suggest that ALC cells equally express ANPR-A and ANPR-B, while A-3 cells express ANPR-B dominantly. Although the physiological roles of these receptors in the bone marrow is still not resolved, ANP is expected to play a role in the regulation of stromal cell functions in bone marrow.

Growth factor pleiotropy is controlled by a receptor Tyr/Ser motif that acts as a binary switch

PubMed Central

Guthridge, Mark A; Powell, Jason A; Barry, Emma F; Stomski, Frank C; McClure, Barbara J; Ramshaw, Hayley; Felquer, Fernando A; Dottore, Mara; Thomas, Daniel T; To, Bik; Begley, C Glenn; Lopez, Angel F

2006-01-01

Pleiotropism is a hallmark of cytokines and growth factors; yet, the underlying mechanisms are not clearly understood. We have identified a motif in the granulocyte macrophage-colony-stimulating factor receptor composed of a tyrosine and a serine residue that functions as a binary switch for the independent regulation of multiple biological activities. Signalling occurs either through Ser585 at lower cytokine concentrations, leading to cell survival only, or through Tyr577 at higher cytokine concentrations, leading to cell survival as well as proliferation, differentiation or functional activation. The phosphorylation of Ser585 and Tyr577 is mutually exclusive and occurs via a unidirectional mechanism that involves protein kinase A and tyrosine kinases, respectively, and is deregulated in at least some leukemias. We have identified similar Tyr/Ser motifs in other cell surface receptors, suggesting that such signalling switches may play important roles in generating specificity and pleiotropy in other biological systems. PMID:16437163

Structural basis for signal recognition and transduction by platelet-activating-factor receptor.

PubMed

Cao, Can; Tan, Qiuxiang; Xu, Chanjuan; He, Lingli; Yang, Linlin; Zhou, Ye; Zhou, Yiwei; Qiao, Anna; Lu, Minmin; Yi, Cuiying; Han, Gye Won; Wang, Xianping; Li, Xuemei; Yang, Huaiyu; Rao, Zihe; Jiang, Hualiang; Zhao, Yongfang; Liu, Jianfeng; Stevens, Raymond C; Zhao, Qiang; Zhang, Xuejun C; Wu, Beili

2018-06-01

Platelet-activating-factor receptor (PAFR) responds to platelet-activating factor (PAF), a phospholipid mediator of cell-to-cell communication that exhibits diverse physiological effects. PAFR is considered an important drug target for treating asthma, inflammation and cardiovascular diseases. Here we report crystal structures of human PAFR in complex with the antagonist SR 27417 and the inverse agonist ABT-491 at 2.8-Å and 2.9-Å resolution, respectively. The structures, supported by molecular docking of PAF, provide insights into the signal-recognition mechanisms of PAFR. The PAFR-SR 27417 structure reveals an unusual conformation showing that the intracellular tips of helices II and IV shift outward by 13 Å and 4 Å, respectively, and helix VIII adopts an inward conformation. The PAFR structures, combined with single-molecule FRET and cell-based functional assays, suggest that the conformational change in the helical bundle is ligand dependent and plays a critical role in PAFR activation, thus greatly extending knowledge about signaling by G-protein-coupled receptors.

Yersinia pestis targets neutrophils via complement receptor 3

PubMed Central

Merritt, Peter M.; Nero, Thomas; Bohman, Lesley; Felek, Suleyman; Krukonis, Eric S.; Marketon, Melanie M.

2015-01-01

Yersinia species display a tropism for lymphoid tissues during infection, and the bacteria select innate immune cells for delivery of cytotoxic effectors by the type III secretion system. Yet the mechanism for target cell selection remains a mystery. Here we investigate the interaction of Yersinia pestis with murine splenocytes to identify factors that participate in the targeting process. We find that interactions with primary immune cells rely on multiple factors. First, the bacterial adhesin Ail is required for efficient targeting of neutrophils in vivo. However, Ail does not appear to directly mediate binding to a specific cell type. Instead, we find that host serum factors direct Y. pestis to specific innate immune cells, particularly neutrophils. Importantly, specificity towards neutrophils was increased in the absence of bacterial adhesins due to reduced targeting of other cell types, but this phenotype was only visible in the presence of mouse serum. Addition of antibodies against complement receptor 3 and CD14 blocked target cell selection, suggesting that a combination of host factors participate in steering bacteria toward neutrophils during plague infection. PMID:25359083

Emerging intracellular receptors for hemorrhagic fever viruses.

PubMed

Jae, Lucas T; Brummelkamp, Thijn R

2015-07-01

Ebola virus and Lassa virus belong to different virus families that can cause viral hemorrhagic fever, a life-threatening disease in humans with limited treatment options. To infect a target cell, Ebola and Lassa viruses engage receptors at the cell surface and are subsequently shuttled into the endosomal compartment. Upon arrival in late endosomes/lysosomes, the viruses trigger membrane fusion to release their genome into the cytoplasm. Although contact sites at the cell surface were recognized for Ebola virus and Lassa virus, it was postulated that Ebola virus requires a critical receptor inside the cell. Recent screens for host factors identified such internal receptors for both viruses: Niemann-Pick disease type C1 protein (NPC1) for Ebola virus and lysosome-associated membrane protein 1 (LAMP1) for Lassa virus. A cellular trigger is needed to permit binding of the viral envelope protein to these intracellular receptors. This 'receptor switch' represents a previously unnoticed step in virus entry with implications for host-pathogen interactions and viral tropism. Copyright © 2015 Elsevier Ltd. All rights reserved.

Signal transduction of Helicobacter pylori during interaction with host cell protein receptors of epithelial and immune cells

PubMed Central

Pachathundikandi, Suneesh Kumar; Tegtmeyer, Nicole; Backert, Steffen

2013-01-01

Helicobacter pylori infections can induce pathologies ranging from chronic gastritis, peptic ulceration to gastric cancer. Bacterial isolates harbor numerous well-known adhesins, vacuolating cytotoxin VacA, protease HtrA, urease, peptidoglycan, and type IV secretion systems (T4SS). It appears that H. pylori targets more than 40 known host protein receptors on epithelial or immune cells. A series of T4SS components such as CagL, CagI, CagY, and CagA can bind to the integrin α5β1 receptor. Other targeted membrane-based receptors include the integrins αvβ3, αvβ5, and β2 (CD18), RPTP-α/β, GP130, E-cadherin, fibronectin, laminin, CD46, CD74, ICAM1/LFA1, T-cell receptor, Toll-like receptors, and receptor tyrosine kinases EGFR, ErbB2, ErbB3, and c-Met. In addition, H. pylori is able to activate the intracellular receptors NOD1, NOD2, and NLRP3 with important roles in innate immunity. Here we review the interplay of various bacterial factors with host protein receptors. The contribution of these interactions to signal transduction and pathogenesis is discussed. PMID:24280762

Epidermal Growth Factor (EGF) Receptor Intron 1 CA Repeat Polymorphisms in African-American and Caucasian Males: Influence on Prostate Cancer Risk or Disease Progression and Interaction with Androgen Receptor CAG Repeat Polymorphisms

DTIC Science & Technology

2003-09-01

Adipose Stromal Cells from Tumescent Liposuction Procedures. American Society for Dermatologic Surgery, $15,000 direct, 11/01/01 -10/31/02. 1999...stromal cells from tumescent liposuction procedures" ASDS Annual Meeting, Chicago, IL, November 1,2002."Adult Multipotent Stem Cells", Coriell

Identification of a G protein coupled receptor induced in activated T cells.

PubMed

Kaplan, M H; Smith, D I; Sundick, R S

1993-07-15

Many genes are induced after T cell activation to make a cell competent for proliferation and ultimately, function. Many of these genes encode surface receptors for growth factors that signal a cell to proliferate. We have cloned a novel gene (clone 6H1) that codes for a member of the G protein-coupled receptor superfamily. This gene was isolated from a chicken activated T cell cDNA library by low level hybridization to mammalian IL-2 cDNA probes. The 308 amino acid open reading frame has seven hydrophobic, presumably transmembrane domains and a consensus site for interaction with G proteins. Tissue distribution studies suggest that gene expression is restricted to activated T cells. The message appears by 1 h after activation and is maintained for at least 45 h. Transcription of 6H1 is induced by a number of T cell stimuli and is inhibited by cyclosporin A, but not by cycloheximide. This is the first description of a member of this superfamily expressed specifically in activated T cells. The gene product may provide a link between T cell growth factors and G protein activation.

The tyrosine kinase inhibitor ZD6474 blocks proliferation of RET mutant medullary thyroid carcinoma cells.

PubMed

Vitagliano, Donata; De Falco, Valentina; Tamburrino, Anna; Coluzzi, Sabrina; Troncone, Giancarlo; Chiappetta, Gennaro; Ciardiello, Fortunato; Tortora, Giampaolo; Fagin, James A; Ryan, Anderson J; Carlomagno, Francesca; Santoro, Massimo

2011-02-01

Oncogenic conversion of the RET tyrosine kinase is a frequent feature of medullary thyroid carcinoma (MTC). ZD6474 (vandetanib) is an ATP-competitive inhibitor of RET, epidermal growth factor receptor (EGFR), and vascular endothelial growth factor receptors kinases. In this study, we have studied ZD6474 mechanism of action in TT and MZ-CRC-1 human MTC cell lines, carrying cysteine 634 to tryptophan (C634W) and methionine 918 to threonine (M918T) RET mutation respectively. ZD6474 blunted MTC cell proliferation and RET, Shc and p44/p42 mitogen-activated protein kinase (MAPK) phosphorylation. Single receptor knockdown by RNA interference showed that MTC cells depended on RET for proliferation. Adoptive expression of the ZD6474-resistant V804M RET mutant rescued proliferation of TT cells under ZD6474 treatment, showing that RET is a key ZD6474 target in these MTC cells. Upon RET inhibition, adoptive stimulation of EGFR partially rescued TT cell proliferation, MAPK signaling, and expression of cell-cycle-related genes. This suggests that simultaneous inhibition of RET and EGFR by ZD6474 may overcome the risk of MTC cells to escape from RET blockade through compensatory over-activation of EGFR.

Regulation of cytokine receptors by Golgi N-glycan processing and endocytosis.

PubMed

Partridge, Emily A; Le Roy, Christine; Di Guglielmo, Gianni M; Pawling, Judy; Cheung, Pam; Granovsky, Maria; Nabi, Ivan R; Wrana, Jeffrey L; Dennis, James W

2004-10-01

The Golgi enzyme beta1,6 N-acetylglucosaminyltransferase V (Mgat5) is up-regulated in carcinomas and promotes the substitution of N-glycan with poly N-acetyllactosamine, the preferred ligand for galectin-3 (Gal-3). Here, we report that expression of Mgat5 sensitized mouse cells to multiple cytokines. Gal-3 cross-linked Mgat5-modified N-glycans on epidermal growth factor and transforming growth factor-beta receptors at the cell surface and delayed their removal by constitutive endocytosis. Mgat5 expression in mammary carcinoma was rate limiting for cytokine signaling and consequently for epithelial-mesenchymal transition, cell motility, and tumor metastasis. Mgat5 also promoted cytokine-mediated leukocyte signaling, phagocytosis, and extravasation in vivo. Thus, conditional regulation of N-glycan processing drives synchronous modification of cytokine receptors, which balances their surface retention against loss via endocytosis.

Integrating Novel Therapeutic Monoclonal Antibodies into the Management of Head and Neck Cancer

PubMed Central

Bauman, Julie E.; Ferris, Robert L.

2014-01-01

Head and neck squamous cell carcinoma (HNSCC) is an immunosuppressive malignancy. Interest in developing novel immunotherapies in HNSCC has been reawakened by the success of cetuximab, a therapeutic monoclonal antibody (mAb) against the epidermal growth factor receptor which likely relies on immune as well as anti-signaling mechanisms. We focus on novel therapeutic mAb in current clinical development against established mechanisms of immune evasion in HNSCC, targeting: tumor antigens (TA), with resultant potential to induce antibody-dependent cell-mediated cytotoxicity and T cell activation; immunosuppressive cytokines; co-stimulatory Tumor Necrosis Factor (TNF)-family receptors; and co-inhibitory immune checkpoint receptors. Clinical trials of immunotherapeutic mAb as monotherapy, in combination with cytolytic standard therapies exposing TA or in combination with other immunomodulatory mAb, are urgently needed in HNSCC. PMID:24222079

Regulation and signaling of human bombesin receptors and their biological effects.

PubMed

Weber, H Christian

2009-02-01

This review will highlight recent advances in the understanding of molecular mechanisms by which mammalian bombesin receptors are regulated and which intracellular signaling pathways have been characterized to mediate agonist-dependent receptor biological effects. Mammalian bombesin receptors have been demonstrated to be involved in a larger array of physiological and pathophysiological conditions than previously reported. Pharmacological experiments in vitro and in vivo as well as utilization of animals genetically deficient of the gastrin-releasing peptide receptor demonstrated roles in memory and fear behavior, lung development and injury, small intestinal cell repair, autocrine tumor growth, and mediating signals for pruritus and penile reflexes. Intracellular signaling studies predominantly of the gastrin-releasing peptide receptor owing to its frequent overexpression in some human malignancies showed that PI3 kinase activation is an important mechanism of cell proliferation. Tumor cell treatment including gastrin-releasing peptide receptor antagonists combined with inhibition of epidermal growth factor receptor resulted in an additive effect on blocking cell proliferation. Novel molecular mechanisms of the orphan bombesin receptor subtype-3 and gastrin-releasing peptide receptor gene regulation have been elucidated. Inhibition of gastrin-releasing peptide receptor signaling in human malignancies represents an attractive target for pharmacological treatment. Novel functions of bombesin related peptides have been identified including processes in the central nervous system, lung and intestinal tract.

Development of EMab-51, a Sensitive and Specific Anti-Epidermal Growth Factor Receptor Monoclonal Antibody in Flow Cytometry, Western Blot, and Immunohistochemistry.

PubMed

Itai, Shunsuke; Kaneko, Mika K; Fujii, Yuki; Yamada, Shinji; Nakamura, Takuro; Yanaka, Miyuki; Saidoh, Noriko; Handa, Saori; Chang, Yao-Wen; Suzuki, Hiroyoshi; Harada, Hiroyuki; Kato, Yukinari

2017-10-01

The epidermal growth factor receptor (EGFR) is a member of the human epidermal growth factor receptor (HER) family of receptor tyrosine kinases and is involved in cell growth and differentiation. EGFR homodimers or heterodimers with other HER members, such as HER2 and HER3, activate downstream signaling cascades in many cancers. In this study, we developed novel anti-EGFR monoclonal antibodies (mAbs) and characterized their efficacy in flow cytometry, Western blot, and immunohistochemical analyses. First, we expressed the full-length or ectodomain of EGFR in LN229 glioblastoma cells and then immunized mice with LN229/EGFR or ectodomain of EGFR, and performed the first screening using enzyme-linked immunosorbent assays. Subsequently, we selected mAbs according to their efficacy in flow cytometry (second screening), Western blot (third screening), and immunohistochemical (fourth screening) analyses. Among 100 mAbs, only one clone EMab-51 (IgG 1 , kappa) reacted with EGFR in Western blot analysis. Finally, immunohistochemical analyses with EMab-51 showed sensitive and specific reactions against oral cancer cells, warranting the use of EMab-51 to detect EGFR in pathological analyses of EGFR-expressing cancers.

Gene therapy of murine teratocarcinoma: separate functions for insulin-like growth factors I and II in immunogenicity and differentiation.

PubMed Central

Trojan, J; Johnson, T R; Rudin, S D; Blossey, B K; Kelley, K M; Shevelev, A; Abdul-Karim, F W; Anthony, D D; Tykocinski, M L; Ilan, J

1994-01-01

Teratocarcinoma is a germ-line carcinoma giving rise to an embryoid tumor with structures derived from the three embryonic layers: mesoderm, endoderm, and ectoderm. Teratocarcinoma is widely used as an in vitro model system to study regulation of cell determination and differentiation during mammalian embryogenesis. Murine embryonic carcinoma (EC) PCC3 cells express insulin-like growth factor I(IGF-I) and its receptor, while all derivative tumor structures express IGF-I and IGF-II and their receptors. Therefore the system lends itself to dissect the role of these two growth factors during EC differentiation. With an episomal antisense strategy, we define a role for IGF-I in tumorigenicity and evasion of immune surveillance. Antisense IGF-I EC transfectants are shown to elicit a curative anti-tumor immune response with tumor regression at distal sites. In contrast, IGF-II is shown to drive determination and differentiation in EC cells. Since IGF-I and IGF-II bind to type I receptor and antisense sequence used for IGF-II cannot form duplex with endogenous IGF-I transcripts, it follows that this receptor is not involved in determination and differentiation. Images PMID:8016120

Diminished survival of human cytotrophoblast cells exposed to hypoxia/reoxygenation injury and associated reduction of heparin-binding epidermal growth factor-like growth factor.

PubMed

Leach, Richard E; Kilburn, Brian A; Petkova, Anelia; Romero, Roberto; Armant, D Randall

2008-04-01

The antiapoptotic action of heparin-binding epidermal growth factor (HBEGF)-like growth factor and its regulation by O(2) constitutes a key factor for trophoblast survival. The hypothesis that cytotrophoblast survival is compromised by exposure to hypoxia-reoxygenation (H/R) injury, which may contribute to preeclampsia and some missed abortions, prompted us to investigate HBEGF regulation and its role as a survival factor during H/R in cytotrophoblast cells. A transformed human first-trimester cytotrophoblast cell line HTR-8/SVneo was exposed to H/R (2% O(2) followed by 20% O(2)) and assessed for HBEGF expression and cell death. Cellular HBEGF declined significantly within 30 minutes of reoxygenation after culture at 2% O(2). H/R significantly reduced proliferation and increased cell death when compared with trophoblast cells cultured continuously at 2% or 20% O(2). Restoration of cell survival also was achieved by adding recombinant HBEGF during reoxygenation. HBEGF inhibited apoptosis through its binding to either human epidermal receptor (HER)-1 or HER4, its cognate receptors. These results provide evidence that cytotrophoblast exposure to H/R induces apoptosis and decreased cell proliferation. HBEGF accumulation is diminished under these conditions, whereas restoration of HBEGF signaling improves trophoblast survival.

Effects of selective type I and II adrenal steroid agonists on immune cell distribution.

PubMed

Miller, A H; Spencer, R L; hassett, J; Kim, C; Rhee, R; Ciurea, D; Dhabhar, F; McEwen, B; Stein, M

1994-11-01

Adrenal steroids exert their effects through two distinct adrenal steroid receptor subtypes; the high affinity type I, or mineralocorticoid, receptor and the lower affinity type II, or glucocorticoid, receptor. Adrenal steroids have well known effects on immune cell distribution, and although both type I and II receptors are expressed in immune cells and tissues, few data exist on the relative effects mediated through these two receptor subtypes. Accordingly, we administered selective type I and II adrenal steroid receptor agonists to young adult male Sprague-Dawley rats for 7 days and then measured immune cell distribution in the peripheral blood and spleen. Results were compared with those of similar studies using the naturally occurring glucocorticoid of the rat, corticosterone, which binds both type I and II receptors. The majority of the well characterized effects of adrenal steroids on peripheral blood immune cells (increased neutrophils and decreased lymphocytes and monocytes) were reproduced by the type II receptor agonist, RU28362. RU28362 decreased the numbers of all lymphocyte subsets [T-cells, B-cells, and natural killer (NK) cells] to very low absolute levels. The largest relative decrease (i.e. in percentage) was seen in B-cells, whereas NK cells exhibited the least relative decrease and actually showed a 2-fold increase in relative percentage during RU28362 treatment. Similar to RU28362, the type I receptor agonist, aldosterone, significantly reduced the number of lymphocytes and monocytes. In contrast to RU28362, however, aldosterone significantly decreased the number of neutrophils. Moreover, aldosterone decreased the number of T-helper cells and NK cells, while having no effect on the number of B-cells or T-suppressor/cytotoxic cells. Corticosterone at physiologically relevant concentrations had potent effects on immune cell distribution, which were indistinguishable from those of the type II receptor agonist, RU28362. Taken together, these results indicate that effects of adrenal steroids on immune cell distribution are dependent on the receptor subtype involved as well as the specific cell type targeted. These factors allow for varied and complex effects of adrenal steroids on the immune system under physiological conditions.

The insulin receptor.

PubMed

Kaplan, S A

1984-03-01

Cells are endowed with specific cognitive molecules that function as receptors for hormones, neurotransmitters, and other intercellular messengers. The receptor molecules may be present in the plasma membrane, cytoplasm, or nucleus. When occupied by the messenger, the receptor is coupled to the cellular machinery that responds to the message-bearing molecules. For some hormones the events following attachment of the messenger to the receptor are well known. An example is the generation of cAMP after combination of glucagon with its receptor and the series of steps culminating in activation of phosphorylase. In the case of many other messengers, including insulin, the nature of these coupling steps is not known. Receptors are subject to the regulatory processes of synthesis, degradation, and conformational change; alterations in receptor properties may have significant effects on the qualitative and quantitative responses of the cell to the extracellular messenger. The insulin receptor is located in the plasma membrane, is composed of two pairs of subunits, and has a molecular weight of about 350,000. It is located in cells such as adipocytes, hepatocytes, and skeletal muscle cells as well as in cells not considered to be typical target organ cells. Insulin receptors in nonfetal cells are downregulated by exposure of the cells to high concentrations of insulin. Other factors that regulate insulin binding include muscular exercise, diet, thyroid hormones, glucocorticoids, androgens, estrogens, and cyclic nucleotides. The fetus has high concentrations of insulin receptors in several tissues. These begin to appear early in fetal life and may outnumber those found in adult tissues. Fetal insulin receptors are unusual in that they may not undergo downregulation but may experience the opposite when exposed to insulin in high concentrations. Thus the offspring of a mother with poorly controlled diabetes may be placed in double jeopardy by fetal hyperinsulinemia and augmented insulin binding by the receptors. Many disorders in children and adults are associated with changes in the properties of the insulin receptor. In general, the alterations have been measured in receptor-bearing cells that are readily accessible, such as circulating monocytes and erythrocytes. The receptors on these cells generally reflect the status of receptors on the major target organs of insulin, although exceptions are known, and conclusions drawn from studies of receptors on circulating cells must be made with caution.(ABSTRACT TRUNCATED AT 400 WORDS)

Differential CLE peptide perception by plant receptors implicated from structural and functional analyses of TDIF-TDR interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Zhijie; Chakraborty, Sayan; Xu, Guozhou

Tracheary Element Differentiation Inhibitory Factor (TDIF) belongs to the family of post-translationally modified CLE (CLAVATA3/embryo surrounding region (ESR)-related) peptide hormones that control root growth and define the delicate balance between stem cell proliferation and differentiation in SAM (shoot apical meristem) or RAM (root apical meristem). In Arabidopsis, Tracheary Element Differentiation Inhibitory Factor Receptor (TDR) and its ligand TDIF signaling pathway is involved in the regulation of procambial cell proliferation and inhibiting its differentiation into xylem cells. Here we present the crystal structures of the extracellular domains (ECD) of TDR alone and in complex with its ligand TDIF resolved at 2.65more » Åand 2.75 Å respectively. These structures provide insights about the ligand perception and specific interactions between the CLE peptides and their cognate receptors. Our in vitro biochemical studies indicate that the interactions between the ligands and the receptors at the C-terminal anchoring site provide conserved binding. While the binding interactions occurring at the N-terminal anchoring site dictate differential binding specificities between different ligands and receptors. Our studies will open different unknown avenues of TDR-TDIF signaling pathways that will enhance our knowledge in this field highlighting the receptor ligand interaction, receptor activation, signaling network, modes of action and will serve as a structure function relationship model between the ligand and the receptor for various similar leucine-rich repeat receptor-like kinases (LRR-RLKs).« less

Regulation of Oligomeric Organization of the Serotonin 5-Hydroxytryptamine 2C (5-HT2C) Receptor Observed by Spatial Intensity Distribution Analysis*

PubMed Central

Ward, Richard J.; Pediani, John D.; Godin, Antoine G.; Milligan, Graeme

2015-01-01

The questions of whether G protein-coupled receptors exist as monomers, dimers, and/or oligomers and if these species interconvert in a ligand-dependent manner are among the most contentious current issues in biology. When employing spatial intensity distribution analysis to laser scanning confocal microscope images of cells stably expressing either a plasma membrane-associated form of monomeric enhanced green fluorescent protein (eGFP) or a tandem version of this fluorophore, the eGFP tandem was identified as a dimer. Similar studies on cells stably expressing an eGFP-tagged form of the epidermal growth factor receptor demonstrated that, although largely a monomer in the basal state, this receptor rapidly became predominantly dimeric upon the addition of its ligand epidermal growth factor. In cells induced to express an eGFP-tagged form of the serotonin 5-hydroxytryptamine 2C (5-HT2C) receptor, global analysis of construct quantal brightness was consistent with the predominant form of the receptor being dimeric. However, detailed spatial intensity distribution analysis demonstrated the presence of multiple forms ranging from monomers to higher-order oligomers. Furthermore, treatment with chemically distinct 5-HT2C receptor antagonists resulted in a time-dependent change in the quaternary organization to one in which there was a preponderance of receptor monomers. This antagonist-mediated effect was reversible, because washout of the ligand resulted in the regeneration of many of the oligomeric forms of the receptor. PMID:25825490

Nuclear actions of insulin-like growth factor binding protein-3.

PubMed

Baxter, Robert C

2015-09-10

In addition to its actions outside the cell, cellular uptake and nuclear import of insulin-like growth factor binding protein-3 (IGFBP-3) has been recognized for almost two decades, but knowledge of its nuclear actions has been slow to emerge. IGFBP-3 has a functional nuclear localization signal and interacts with the nuclear transport protein importin-β. Within the nucleus IGFBP-3 appears to have a role in transcriptional regulation. It can bind to the nuclear receptor, retinoid X receptor-α and several of its dimerization partners, including retinoic acid receptor, vitamin D receptor (VDR), and peroxisome proliferator-activated receptor-γ (PPARγ). These interactions modulate the functions of these receptors, for example inhibiting VDR-dependent transcription in osteoblasts and PPARγ-dependent transcription in adipocytes. Nuclear IGFBP-3 can be detected by immunohistochemistry in cancer and other tissues, and its presence in the nucleus has been shown in many cell culture studies to be necessary for its pro-apoptotic effect, which may also involve interaction with the nuclear receptor Nur77, and export from the nucleus. IGFBP-3 is p53-inducible and in response to DNA damage, forms a complex with the epidermal growth factor receptor (EGFR), translocating to the nucleus to interact with DNA-dependent protein kinase. Inhibition of EGFR kinase activity or downregulation of IGFBP-3 can inhibit DNA double strand-break repair by nonhomologous end joining. IGFBP-3 thus has the ability to influence many cell functions through its interactions with intranuclear pathways, but the importance of these interactions in vivo, and their potential to be targeted for therapeutic benefit, require further investigation. Copyright © 2015 Elsevier B.V. All rights reserved.

CXCL4/Platelet Factor 4 is an agonist of CCR1 and drives human monocyte migration.

PubMed

Fox, James M; Kausar, Fahima; Day, Amy; Osborne, Michael; Hussain, Khansa; Mueller, Anja; Lin, Jessica; Tsuchiya, Tomoko; Kanegasaki, Shiro; Pease, James E

2018-06-21

Activated platelets release micromolar concentrations of the chemokine CXCL4/Platelet Factor-4. Deposition of CXCL4 onto the vascular endothelium is involved in atherosclerosis, facilitating monocyte arrest and recruitment by an as yet, unidentified receptor. Here, we demonstrate that CXCL4 drives chemotaxis of the monocytic cell line THP-1. Migration and intracellular calcium responses induced by CXCL4 were pertussis toxin-sensitive, implicating a GPCR in signal transduction. Cell treatment with chondroitinase ABC ablated migration, suggesting that cis presentation of CXCL4 by cell surface glycosaminoglycans to a GPCR is required. Although CXCR3 has been previously described as a CXCL4 receptor, THP-1 cells were unresponsive to CXCR3 ligands and CXCL4-induced migration was insensitive to a CXCR3 antagonist, suggesting that an alternative receptor is involved. Interrogating CC-class chemokine receptor transfectants, we unexpectedly found that CXCL4 could induce the migration of CCR1-expressing cells and also induce CCR1 endocytosis. Extending our findings to primary human monocytes, we observed that CXCL4 induced CCR1 endocytosis and could induce monocyte chemotaxis in a CCR1 antagonist-sensitive manner. Collectively, our data identify CCR1 as a previously elusive monocyte CXCL4 receptor and suggest that CCR1 may play a role in inflammation where the release of CXCL4 is implicated.

Soluble VEGF receptor 1 (sFLT1) induces non-apoptotic death in ovarian and colorectal cancer cells

PubMed Central

Miyake, Tatsuya; Kumasawa, Keiichi; Sato, Noriko; Takiuchi, Tsuyoshi; Nakamura, Hitomi; Kimura, Tadashi

2016-01-01

Soluble Vascular Endothelial Growth Factor Receptor 1 (sVEGFR1/sFLT1) is an angiogenesis inhibitor that competes with angiogenic factors such as VEGF and Placental Growth Factor (PlGF). Imbalances of VEGF and sFLT1 levels can cause pathological conditions such as tumour growth or preeclampsia. We observed direct damage caused by sFLT1 in tumour cells. We exposed several kinds of cells derived from ovarian and colorectal cancers as well as HEK293T cells to sFLT1 in two ways, transfection and exogenous application. The cell morphology and an LDH assay revealed cytotoxicity. Additional experiments were performed to clarify how sFLT1 injured cells. In this study, non-apoptotic cell damage was found to be induced by sFLT1. Moreover, sFLT1 showed an anti-tumour effect in a mouse model of ovarian cancer. Our results suggest that sFLT1 has potential as a cancer therapeutic candidate. PMID:27103202

Role of Insulin-Like Growth Factor-1 Signaling Pathway in Cisplatin-Resistant Lung Cancer Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun Yunguang; Zheng Siyuan; Torossian, Artour

2012-03-01

Purpose: The development of drug-resistant phenotypes has been a major obstacle to cisplatin use in non-small-cell lung cancer. We aimed to identify some of the molecular mechanisms that underlie cisplatin resistance using microarray expression analysis. Methods and Materials: H460 cells were treated with cisplatin. The differences between cisplatin-resistant lung cancer cells and parental H460 cells were studied using Western blot, MTS, and clonogenic assays, in vivo tumor implantation, and microarray analysis. The cisplatin-R cells were treated with human recombinant insulin-like growth factor (IGF) binding protein-3 and siRNA targeting IGF-1 receptor. Results: Cisplatin-R cells illustrated greater expression of the markers CD133more » and aldehyde dehydrogenase, more rapid in vivo tumor growth, more resistance to cisplatin- and etoposide-induced apoptosis, and greater survival after treatment with cisplatin or radiation than the parental H460 cells. Also, cisplatin-R demonstrated decreased expression of insulin-like growth factor binding protein-3 and increased activation of IGF-1 receptor signaling compared with parental H460 cells in the presence of IGF-1. Human recombinant IGF binding protein-3 reversed cisplatin resistance in cisplatin-R cells and targeting of IGF-1 receptor using siRNA resulted in sensitization of cisplatin-R-cells to cisplatin and radiation. Conclusions: The IGF-1 signaling pathway contributes to cisplatin-R to cisplatin and radiation. Thus, this pathway represents a potential target for improved lung cancer response to treatment.« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinez-Garcia, Eva; Irigoyen, Marta; Anso, Elena

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 emittedmore » 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.« less

Receptor Signaling Directs Global Recruitment of Pre-existing Transcription Factors to Inducible Elements.

PubMed

Cockerill, Peter N

2016-12-01

Gene expression programs are largely regulated by the tissue-specific expression of lineage-defining transcription factors or by the inducible expression of transcription factors in response to specific stimuli. Here I will review our own work over the last 20 years to show how specific activation signals also lead to the wide-spread re-distribution of pre-existing constitutive transcription factors to sites undergoing chromatin reorganization. I will summarize studies showing that activation of kinase signaling pathways creates open chromatin regions that recruit pre-existing factors which were previously unable to bind to closed chromatin. As models I will draw upon genes activated or primed by receptor signaling in memory T cells, and genes activated by cytokine receptor mutations in acute myeloid leukemia. I also summarize a hit-and-run model of stable epigenetic reprograming in memory T cells, mediated by transient Activator Protein 1 (AP-1) binding, which enables the accelerated activation of inducible enhancers.

Thrombin-induced p38 mitogen-activated protein kinase activation is mediated by epidermal growth factor receptor transactivation pathway

PubMed Central

Kanda, Yasunari; Mizuno, Katsushige; Kuroki, Yasutomi; Watanabe, Yasuhiro

2001-01-01

Thrombin is a potent mitogen for vascular smooth muscle cells (VSMC) and has been implicated its pathogenic role in vascular remodelling. However, the signalling pathways by which thrombin mediates its mitogenic response are not fully understood.We have previously reported that thrombin activates p38 mitogen-activated protein kinase (p38 MAPK) by a tyrosine kinase-dependent mechanism, and that p38 MAPK has a role in thrombin-induced mitogenic response in rat VSMC.In the present study, we examine the involvement of epidermal growth factor (EGF) receptor in thrombin-induced p38 MAPK activation. We found that thrombin induced EGF receptor tyrosine phosphorylation (transactivation) in A10 cells, a clonal VSMC cell line. A selective inhibitor of EGF receptor kinase (AG1478) inhibited the p38 MAPK activation in a dose-dependent manner, whereas it had no effect on the response to platelet-derived growth factor (PDGF). EGF receptor phosphorylation induced by thrombin was inhibited by BAPTA-AM and GF109203X, which suggest a requirement for intracellular Ca2+ increase and protein kinase C.We next examined the effect of AG1478 on thrombin-induced DNA synthesis. AG1478 inhibited thrombin-induced DNA synthesis in a dose-dependent manner. In contrast, PDGF-induced DNA synthesis was not affected by AG1478.In conclusion, these data suggest that the EGF receptor transactivation and subsequent p38 MAPK activation is required for thrombin-induced proliferation of VSMC. PMID:11309236

Growth Factors and COX2 Expression in Canine Perivascular Wall Tumors.

PubMed

Avallone, G; Stefanello, D; Boracchi, P; Ferrari, R; Gelain, M E; Turin, L; Tresoldi, E; Roccabianca, P

2015-11-01

Canine perivascular wall tumors (PWTs) are a group of subcutaneous soft tissue sarcomas developing from vascular mural cells. Mural cells are involved in angiogenesis through a complex crosstalk with endothelial cells mediated by several growth factors and their receptors. The evaluation of their expression may have relevance since they may represent a therapeutic target in the control of canine PWTs. The expression of vascular endothelial growth factor (VEGF) and receptors VEGFR-I/II, basic fibroblast growth factor (bFGF) and receptor Flg, platelet-derived growth factor B (PDGFB) and receptor PDGFRβ, transforming growth factor β1 (TGFβ1) and receptors TGFβR-I/II, and cyclooxygenase 2 (COX2) was evaluated on frozen sections of 40 PWTs by immunohistochemistry and semiquantitatively scored to identify their potential role in PWT development. Statistical analysis was performed to analyze possible correlations between Ki67 labeling index and the expression of each molecule. Proteins of the VEGF-, PDGFB-, and bFGF-mediated pathways were highly expressed in 27 (67.5%), 30 (75%), and 19 (47.5%) of 40 PWTs, respectively. Proteins of the TGFβ1- and COX2-mediated pathways were highly expressed in 4 (10%) and 14 (35%) of 40 cases. Statistical analysis identified an association between VEGF and VEGFR-I/II (P = .015 and .003, respectively), bFGF and Flg (P = .038), bFGF and PDGFRβ (P = .003), and between TGFβ1 and COX2 (P = .006). These findings were consistent with the mechanisms that have been reported to play a role in angiogenesis and in tumor development. No association with Ki67 labeling index was found. VEGF-, PDGFB-, and bFGF-mediated pathways seem to have a key role in PWT development and growth. Blockade of tyrosine kinase receptors after surgery could represent a promising therapy with the aim to reduce the PWT relapse rate and prolong the time to relapse. © The Author(s) 2015.

Multiple elements of the allergic arm of the immune response modulate autoimmune demyelination

PubMed Central

Pedotti, Rosetta; DeVoss, Jason J.; Youssef, Sawsan; Mitchell, Dennis; Wedemeyer, Jochen; Madanat, Rami; Garren, Hideki; Fontoura, Paulo; Tsai, Mindy; Galli, Stephen J.; Sobel, Raymond A.; Steinman, Lawrence

2003-01-01

Analysis of mRNA from multiple sclerosis lesions revealed increased amounts of transcripts for several genes encoding molecules traditionally associated with allergic responses, including prostaglandin D synthase, histamine receptor type 1 (H1R), platelet activating factor receptor, Ig Fc ɛ receptor 1 (FcɛRI), and tryptase. We now demonstrate that, in the animal model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE), mediated by T helper 1 (Th1) T cells, histamine receptor 1 and 2 (H1R and H2R) are present on inflammatory cells in brain lesions. Th1 cells reactive to myelin proteolipid protein expressed more H1R and less H2R than Th2 cells. Pyrilamine, an H1R antagonist, blocked EAE, and the platelet activating factor receptor antagonist CV6209 reduced the severity of EAE. EAE severity was also decreased in mice with disruption of the genes encoding Ig FcγRIII or both FcγRIII and FcɛRI. Prostaglandin D synthase and tryptase transcripts were elevated in EAE brain. Taken together, these data reveal extensive involvement of elements of the immune response associated with allergy in autoimmune demyelination. The pathogenesis of demyelination must now be viewed as encompassing elements of both Th1 responses and “allergic” responses. PMID:12576552

Neurotrophin Receptor p75NTR Regulates Immune Function of Plasmacytoid Dendritic Cells.

PubMed

Bandoła, Joanna; Richter, Cornelia; Ryser, Martin; Jamal, Arshad; Ashton, Michelle P; von Bonin, Malte; Kuhn, Matthias; Dorschner, Benjamin; Alexopoulou, Dimitra; Navratiel, Katrin; Roeder, Ingo; Dahl, Andreas; Hedrich, Christian M; Bonifacio, Ezio; Brenner, Sebastian; Thieme, Sebastian

2017-01-01

Plasmacytoid dendritic cells (pDCs) regulate innate and adaptive immunity. Neurotrophins and their receptors control the function of neuronal tissue. In addition, they have been demonstrated to be part of the immune response but little is known about the effector immune cells involved. We report, for the first time, the expression and immune-regulatory function of the low affinity neurotrophin receptor p75 neurotrophin receptor (p75NTR) by the antigen-presenting pDCs, mediated by toll-like receptor (TLR) 9 activation and differential phosphorylation of interferon regulatory factor 3 and 7. The modulation of p75NTR on pDCs significantly influences disease progression of asthma in an ovalbumin-induced mouse model mediated by the TLR9 signaling pathway. p75NTR activation of pDCs from patients with asthma increased allergen-specific T cell proliferation and cytokine secretion in nerve growth factor concentration-dependent manner. Further, p75NTR activation of pDCs delayed the onset of autoimmune diabetes in RIP-CD80GP mice and aggravated graft-versus-host disease in a xenotransplantation model. Thus, p75NTR signaling on pDCs constitutes a new and critical mechanism connecting neurotrophin signaling and immune response regulation with great therapeutic potential for a variety of immune disorders.

Neurotrophin Receptor p75NTR Regulates Immune Function of Plasmacytoid Dendritic Cells

PubMed Central

Bandoła, Joanna; Richter, Cornelia; Ryser, Martin; Jamal, Arshad; Ashton, Michelle P.; von Bonin, Malte; Kuhn, Matthias; Dorschner, Benjamin; Alexopoulou, Dimitra; Navratiel, Katrin; Roeder, Ingo; Dahl, Andreas; Hedrich, Christian M.; Bonifacio, Ezio; Brenner, Sebastian; Thieme, Sebastian

2017-01-01

Plasmacytoid dendritic cells (pDCs) regulate innate and adaptive immunity. Neurotrophins and their receptors control the function of neuronal tissue. In addition, they have been demonstrated to be part of the immune response but little is known about the effector immune cells involved. We report, for the first time, the expression and immune-regulatory function of the low affinity neurotrophin receptor p75 neurotrophin receptor (p75NTR) by the antigen-presenting pDCs, mediated by toll-like receptor (TLR) 9 activation and differential phosphorylation of interferon regulatory factor 3 and 7. The modulation of p75NTR on pDCs significantly influences disease progression of asthma in an ovalbumin-induced mouse model mediated by the TLR9 signaling pathway. p75NTR activation of pDCs from patients with asthma increased allergen-specific T cell proliferation and cytokine secretion in nerve growth factor concentration-dependent manner. Further, p75NTR activation of pDCs delayed the onset of autoimmune diabetes in RIP-CD80GP mice and aggravated graft-versus-host disease in a xenotransplantation model. Thus, p75NTR signaling on pDCs constitutes a new and critical mechanism connecting neurotrophin signaling and immune response regulation with great therapeutic potential for a variety of immune disorders. PMID:28861085

Emerging growth factor receptor antagonists for the treatment of renal cell carcinoma.

PubMed

Zahoor, Haris; Rini, Brian I

2016-12-01

The landscape of systemic treatment for metastatic renal cell carcinoma (RCC) has dramatically changed with the introduction of targeted agents including vascular endothelial growth factor (VEGF) inhibitors. Recently, multiple new agents including growth factor receptor antagonists and a checkpoint inhibitor were approved for the treatment of refractory metastatic RCC based on encouraging benefit shown in clinical trials. Areas covered: The background and biological rationale of existing treatment options including a brief discussion of clinical trials which led to their approval, is presented. This is followed by reviewing the limitations of these therapeutic options, medical need to develop new treatments and major goals of ongoing research. We then discuss two recently approved growth factor receptor antagonists i.e. cabozantinib and lenvatinib, and a recently approved checkpoint inhibitor, nivolumab, and issues pertaining to drug development, and future directions in treatment of metastatic RCC. Expert opinion: Recently approved growth factor receptor antagonists have shown encouraging survival benefit but associated drug toxicity is a major issue. Nivolumab, a programmed death 1 (PD-1) checkpoint inhibitor, has similarly shown survival benefit and is well tolerated. With multiple options now available in this patient population, the right sequence of these agents remains to be determined.

An increase in circulating B cell-activating factor in childhood-onset ocular myasthenia gravis.

PubMed

Motobayashi, Mitsuo; Inaba, Yuji; Nishimura, Takafumi; Kobayashi, Norimoto; Nakazawa, Yozo; Koike, Kenichi

2015-04-01

Myasthenia gravis is a B cell-mediated autoimmune disorder. The pathophysiology of childhood-onset ocular myasthenia gravis remains unclear. We investigated serum B cell-activating factor levels and other immunological parameters in child patients with ocular myasthenia gravis. Blood samples were obtained from 9 children with ocular myasthenia gravis and 20 age-matched controls. We assayed serum concentrations of B cell-activating factor, anti-acetylcholine receptor antibody titers, 7 types of cytokines (interleukins-2, -4, -6, -10, and -17A; interferon-γ; tumor necrosis factor-α) as well as the percentages of peripheral blood CD4+, CD8+, and CD19+ cells. Serum B cell-activating factor levels were significantly higher before immunosuppressive therapy in patients with childhood-onset ocular myasthenia gravis than in controls and decreased after immunosuppressive therapy. A significant positive correlation was observed between serum B cell-activating factor levels and anti-acetylcholine receptor antibody titers in patients with myasthenia gravis. Serum B cell-activating factor concentrations did not correlate with the percentages of CD4+, CD8+, and CD19+ cells or the CD4+/CD8+ ratio. No significant differences were observed in the levels of the 7 different types of cytokines examined, including interleukin-17A, between preimmunosuppressive therapy myasthenia gravis patients and controls. Circulating B cell-activating factor may play a key role in the pathophysiology of childhood-onset ocular myasthenia gravis. Copyright © 2015 Elsevier Inc. All rights reserved.

The Macrophage Galactose-Type Lectin Can Function as an Attachment and Entry Receptor for Influenza Virus

PubMed Central

Ng, Wy Ching; Liong, Stella; Tate, Michelle D.; Irimura, Tatsuro; Denda-Nagai, Kaori; Brooks, Andrew G.; Londrigan, Sarah L.

2014-01-01

Specific protein receptors that mediate internalization and entry of influenza A virus (IAV) have not been identified for any cell type. Sialic acid (SIA), the primary attachment factor for IAV hemagglutinin, is expressed by numerous cell surface glycoproteins and glycolipids, confounding efforts to identify specific receptors involved in virus infection. Lec1 Chinese hamster ovary (CHO) epithelial cells express cell surface SIA and bind IAV yet are largely resistant to infection. Here, we demonstrate that expression of the murine macrophage galactose-type lectin 1 (MGL1) by Lec1 cells enhanced Ca2+-dependent IAV binding and restored permissivity to infection. Lec1 cells expressing MGL1 were infected in the presence or absence of cell surface SIA, indicating that MGL1 can act as a primary receptor or as a coreceptor with SIA. Lec1 cells expressing endocytosis-deficient MGL1 mediated Ca2+-dependent IAV binding but were less sensitive to IAV infection, indicating that direct internalization via MGL1 can result in cellular infection. Together, these studies identify MGL1 as a cell surface glycoprotein that can act as an authentic receptor for both attachment and infectious entry of IAV. PMID:24257596

SC-12CD133 SURFACE EXPRESSION INDICATES ASYMMETRIC INHERITANCE OF SIGNALING RECEPTORS DURING GLIOBLASTOMA CANCER STEM CELL MITOSIS

PubMed Central

Hitomi, Masahiro; Jarvis, Stephanie; Yogeswaran, Vid; Pfaff, Kayla; Lathia, Justin

2014-01-01

Asymmetric cell division, the mechanism by which stem cells generate progeny undergoing tissue specific differentiation and a self-renewing stem cell population, enables organogenesis, maintenance of tissue homeostasis, and tissue regeneration without depleting stem cell pools. Cancer stem cells (CSCs) have been identified in malignant cancers including glioblastoma (GBM) by virtue of their enhanced self-renewal capacity and ability to reconstitute an entire tumor with all types of cells found in the original tumor. CSCs also play pivotal roles in therapeutic resistance and are the focus of recent therapeutic development efforts. CSC maintenance is regulated by intrinsic stem cell transcription factors, as well as by multiple extrinsic factors in the tumor microenvironment. In addition to these factors, the mode of cell division plays a critical role in CSC maintenance as exemplified by normal stem cells. Previously, we demonstrated that asymmetric segregation of a CSC marker, CD133, at the time of mitosis correlated with fate determination of CSCs derived from clinical GBM patient samples. Utilizing quantitative immunofluorecsence, we detected that receptors for key signaling molecules critical for CSC maintenance were co-segregated with CD133. Inhibition of downstream signaling induced asymmetric cell death in one of the daughter cells. These data indicate that CD133 marks daughter cells with higher inheritance of molecules that facilitate self-renewal and that asymmetric cell division may benefit CSC survival by concentrating essential receptors to one daughter cell in addition to its potential role in increasing cellular heterogeneity of the tumor.

Potential influences of complement factor H in autoimmune inflammatory and thrombotic disorders.

PubMed

Ferluga, Janez; Kouser, Lubna; Murugaiah, Valarmathy; Sim, Robert B; Kishore, Uday

2017-04-01

Complement system homeostasis is important for host self-protection and anti-microbial immune surveillance, and recent research indicates roles in tissue development and remodelling. Complement also appears to have several points of interaction with the blood coagulation system. Deficiency and altered function due to gene mutations and polymorphisms in complement effectors and regulators, including Factor H, have been associated with familial and sporadic autoimmune inflammatory - thrombotic disorders, in which autoantibodies play a part. These include systemic lupus erythematosus, rheumatoid arthritis, atypical haemolytic uremic syndrome, anti-phospholipid syndrome and age-related macular degeneration. Such diseases are generally complex - multigenic and heterogeneous in their symptoms and predisposition/susceptibility. They usually need to be triggered by vascular trauma, drugs or infection and non-complement genetic factors also play a part. Underlying events seem to include decline in peripheral regulatory T cells, dendritic cell, and B cell tolerance, associated with alterations in lymphoid organ microenvironment. Factor H is an abundant protein, synthesised in many cell types, and its reported binding to many different ligands, even if not of high affinity, may influence a large number of molecular interactions, together with the accepted role of Factor H within the complement system. Factor H is involved in mesenchymal stem cell mediated tolerance and also contributes to self-tolerance by augmenting iC3b production and opsonisation of apoptotic cells for their silent dendritic cell engulfment via complement receptor CR3, which mediates anti-inflammatory-tolerogenic effects in the apoptotic cell context. There may be co-operation with other phagocytic receptors, such as complement C1q receptors, and the Tim glycoprotein family, which specifically bind phosphatidylserine expressed on the apoptotic cell surface. Factor H is able to discriminate between self and nonself surfaces for self-protection and anti-microbe defence. Factor H, particularly as an abundant platelet protein, may also modulate blood coagulation, having an anti-thrombotic role. Here, we review a number of interaction pathways in coagulation and in immunity, together with associated diseases, and indicate where Factor H may be expected to exert an influence, based on reports of the diversity of ligands for Factor H. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ternary complex factor SAP-1 is required for Erk-mediated thymocyte positive selection.

PubMed

Costello, Patrick S; Nicolas, Robert H; Watanabe, Yasuyuki; Rosewell, Ian; Treisman, Richard

2004-03-01

Thymocyte selection and differentiation requires extracellular signal-regulated kinase (Erk) signaling, but transcription factor substrates of Erk in thymocytes are unknown. We have characterized the function of SAP-1 (Elk4), an Erk-regulated transcription factor, in thymocyte development. Early thymocyte development was normal, but single-positive thymocyte and peripheral T cell numbers were reduced, reflecting a T cell-autonomous defect. T cell receptor-induced activation of SAP-1 target genes such as Egr1 was substantially impaired in double-positive thymocytes, although Erk activation was normal. Analysis of T cell receptor transgenes showed that positive selection was reduced by 80-90% in SAP-1-deficient mice; heterozygous mice showed a moderate defect. Negative selection was unimpaired. SAP-1 thus directly links Erk signaling to the transcriptional events required for thymocyte positive selection.

Gefitinib enhances human colon cancer cells to TRAIL-induced apoptosis of via autophagy- and JNK-mediated death receptors upregulation.

PubMed

Chen, Lei; Meng, Yue; Guo, Xiaoqing; Sheng, Xiaotong; Tai, Guihua; Zhang, Fenglei; Cheng, Hairong; Zhou, Yifa

2016-11-01

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a potent cancer cell-specific apoptosis-inducing cytokine with little toxicity to most normal cells. Here, we report that gefitinib and TRAIL in combination produce a potent synergistic effect on TRAIL-sensitive human colon cancer HCT116 cells and an additive effect on TRAIL-resistant HT-29 cells. Interestingly, gefitinib increases the expression of cell surface receptors DR4 and DR5, possibly explaining the synergistic effect. Knockdown of DR4 and DR5 by siRNA significantly decreases gefitinib- and TRAIL-mediated cell apoptosis, supporting this idea. Because the inhibition of gefitinib-induced autophagy by 3-MA significantly decreases DR4 and DR5 upregulation, as well as reduces gefitinib- and TRAIL-induced apoptosis, we conclude that death receptor upregulation is autophagy mediated. Furthermore, our results indicate that death receptor expression may also be regulated by JNK activation, because pre-treatment of cells with JNK inhibitor SP600125 significantly decreases gefitinib-induced death receptor upregulation. Interestingly, SP600125 also inhibits the expression CHOP, yet CHOP has no impact on death receptor expressions. We also find here that phosphorylation of Akt and ERK might also be required for TRAIL sensitization. In summary, our results indicate that gefitinib effectively enhances TRAIL-induced apoptosis, likely via autophagy and JNK- mediated death receptor expression and phosphorylation of Akt and ERK.

B61 is a ligand for the ECK receptor protein-tyrosine kinase.

PubMed

Bartley, T D; Hunt, R W; Welcher, A A; Boyle, W J; Parker, V P; Lindberg, R A; Lu, H S; Colombero, A M; Elliott, R L; Guthrie, B A

1994-04-07

A protein ligand for the ECK receptor protein-tyrosine kinase has been isolated by using the extracellular domain (ECK-X) of the receptor as an affinity reagent. Initially, concentrated cell culture supernatants were screened for receptor binding activity using immobilized ECK-X in a surface plasmon resonance detection system. Subsequently, supernatants from selected cell lines were fractionated directly by receptor affinity chromatography, resulting in the single-step purification of B61, a protein previously identified as the product of an early response gene induced by tumour necrosis factor-alpha. We report here that recombinant B61 induces autophosphorylation of ECK in intact cells, consistent with B61 being an authentic ligand for ECK. ECK is a member of a large orphan receptor protein-tyrosine kinase family headed by EPH, and we suggest that ligands for other members of this family will be related to B61, and can be isolated in the same way.

DIRECT MODULATION OF THE PROTEIN KINASE A CATALYTIC SUBUNIT α BY GROWTH FACTOR RECEPTOR TYROSINE KINASES

PubMed Central

Caldwell, George B.; Howe, Alan K.; Nickl, Christian K.; Dostmann, Wolfgang R.; Ballif, Bryan A.; Deming, Paula B.

2011-01-01

The cyclic-AMP-dependent protein kinase A (PKA) regulates processes such as cell proliferation and migration following activation of growth factor receptor tyrosine kinases (RTKs), yet the signaling mechanisms that link PKA with growth factor receptors remain largely undefined. Here we report that RTKs can directly modulate the function of the catalytic subunit of PKA (PKA-C) through post-translational modification. In vitro kinase assays revealed that both the epidermal growth factor and platelet derived growth factor receptors (EGFR and PDGFR, respectively) tyrosine phosphorylate PKA-C. Mass spectrometry identified tyrosine 330 (Y330) as a receptor-mediated phosphorylation site and mutation of Y330 to phenylalanine (Y330F) all but abolished the RTK-mediated phosphorylation of PKA-C in vitro. Y330 resides within a conserved region at the C-terminal tail of PKA-C that allosterically regulates enzymatic activity. Therefore, the effect of phosphorylation at Y330 on the activity of PKA-C was investigated. The Km for a peptide substrate was markedly decreased when PKA-C subunits were tyrosine phosphorylated by the receptors as compared to un-phosphorylated controls. Importantly, tyrosine-phosphorylated PKA-C subunits were detected in cells stimulated with EGF, PDGF and FGF2 and in fibroblasts undergoing PDGF-mediated chemotaxis. These results demonstrate a direct, functional interaction between RTKs and PKA-C and identify tyrosine phosphorylation as a novel mechansim for regulating PKA activity. PMID:21866565

The signalling receptor MCAM coordinates apical-basal polarity and planar cell polarity during morphogenesis

PubMed Central

Gao, Qian; Zhang, Junfeng; Wang, Xiumei; Liu, Ying; He, Rongqiao; Liu, Xingfeng; Wang, Fei; Feng, Jing; Yang, Dongling; Wang, Zhaoqing; Meng, Anming; Yan, Xiyun

2017-01-01

The apical–basal (AB) polarity and planar cell polarity (PCP) provide an animal cell population with different phenotypes during morphogenesis. However, how cells couple these two patterning systems remains unclear. Here we provide in vivo evidence that melanoma cell adhesion molecule (MCAM) coordinates AB polarity-driven lumenogenesis and c-Jun N-terminal kinase (JNK)/PCP-dependent ciliogenesis. We identify that MCAM is an independent receptor of fibroblast growth factor 4 (FGF4), a membrane anchor of phospholipase C-γ (PLC-γ), an immediate upstream receptor of nuclear factor of activated T-cells (NFAT) and a constitutive activator of JNK. We find that MCAM-mediated vesicular trafficking towards FGF4, while generating a priority-grade transcriptional response of NFAT determines lumenogenesis. We demonstrate that MCAM plays indispensable roles in ciliogenesis through activating JNK independently of FGF signals. Furthermore, mcam-deficient zebrafish and Xenopus exhibit a global defect in left-right (LR) asymmetric establishment as a result of morphogenetic failure of their LR organizers. Therefore, MCAM coordination of AB polarity and PCP provides insight into the general mechanisms of morphogenesis. PMID:28589943

Expression of chemokine CXCL12 and its receptor CXCR4 in folliculostellate (FS) cells of the rat anterior pituitary gland: the CXCL12/CXCR4 axis induces interconnection of FS cells.

PubMed

Horiguchi, Kotaro; Ilmiawati, Cimi; Fujiwara, Ken; Tsukada, Takehiro; Kikuchi, Motoshi; Yashiro, Takashi

2012-04-01

The anterior pituitary gland is composed of five types of hormone-producing cells plus folliculostellate (FS) cells, which do not produce classical anterior pituitary hormones. FS cells are interconnected by cytoplasmic processes and encircle hormone-producing cells or aggregate homophilically. Using living-cell imaging of primary culture, we recently reported that some FS cells precisely extend their cytoplasmic processes toward other FS cells and form interconnections with them. These phenomena suggest the presence of a chemoattractant factor that facilitates the interconnection. In this study, we attempted to discover the factor that induces interconnection of FS cells and succeeded in identifying chemokine (CXC)-L12 and its receptor CXCR4 as potential candidate molecules. CXCL12 is a chemokine of the CXC subfamily. It exerts its effects via CXCR4, a G protein-coupled receptor. The CXCL12/CXCR4 axis is a potent chemoattractant for many types of neural cells. First, we revealed that CXCL12 and CXCR4 are expressed by FS cells in rat anterior pituitary gland. Next, to clarify the function of the CXCL12/CXCR4 axis in FS cells, we observed living anterior pituitary cells in primary culture with specific CXCL12 inhibitor or CXCR4 antagonist and noted that extension of cytoplasmic processes and interconnection of FS cells were inhibited. Finally, we examined FS cell migration and invasion by using Matrigel matrix assays. CXCL12 treatment resulted in markedly increased FS cell migration and invasion. These data suggest that FS cells express chemokine CXCL12 and its receptor CXCR4 and that the CXCL12/CXCR4 axis evokes interconnection of FS cells.

Expression profiling of G-protein-coupled receptors in human urothelium and related cell lines.

PubMed

Ochodnický, Peter; Humphreys, Sian; Eccles, Rachel; Poljakovic, Mirjana; Wiklund, Peter; Michel, Martin C

2012-09-01

What's known on the subject? and What does the study add? Urothelium emerged as a crucial integrator of sensory inputs and outputs in the bladder wall, and urothelial G-protein-coupled receptors (GPCRs) may represent plausible targets for treatment of various bladder pathologies. Urothelial cell lines provide a useful tool to study urothelial receptor function, but their validity as models for native human urothelium remains unclear. We characterize the mRNA expression of genes coding for GPCRs in human freshly isolated urothelium and compare the expression pattern with those in human urothelial cell lines. To characterize the mRNA expression pattern of genes coding for G-protein-coupled receptors (GPCRs) in human freshly isolated urothelium. To compare GPCR expression in human urothelium-derived cell lines to explore the suitability of these cell lines as model systems to study urothelial function. Native human urothelium (commercially sourced) and human urothelium-derived non-cancer (UROtsa and TERT-NHUC) and cancer (J82) cell lines were used. For mRNA expression profiling we used custom-designed real-time polymerase chain reaction array for 40 receptors and several related genes. Native urothelium expressed a wide variety of GPCRs, including α(1A), α(1D) and all subtypes of α(2) and β adrenoceptors. In addition, M(2) and M(3) cholinergic muscarinic receptors, angiotensin II AT(1) receptor, serotonin 5-HT(2A) receptor and all subtypes of bradykinin, endothelin, cannabinoid, tachykinin and sphingosine-1-phosphate receptors were detected. Nerve growth factor and both its low- and high-affinity receptors were also expressed in urothelium. In all cell lines expression of most GPCRs was markedly downregulated, with few exceptions. In UROtsa cells, but much less in other cell lines, the expression of β(2) adrenoceptors, M(3) muscarinic receptors, B(1) and B(2) bradykinin receptors, ET(B) endothelin receptors and several subtypes of sphingosine-1-phosphate receptors was largely retained. Human urothelium expresses a wide range of receptors which enables sensing and integration of various extracellular signals. Human urothelium-derived cell lines, especially UROtsa cells, show comparable mRNA expression to native tissue for several physiologically relevant GPCRs, but lose expression of many other receptors. The use of cell lines as model systems of human urothelium requires careful validation of suitability for the genes of interest. © 2012 BJU INTERNATIONAL.

Interactions between insulin-like growth factor-I, estrogen receptor-α (ERα) and ERβ in regulating growth/apoptosis of MCF-7 human breast cancer cells

PubMed Central

Mendoza, Rhone A.; Enriquez, Marlene I; Mejia, Sylvia M; Moody, Emily E; Thordarson, Gudmundur

2011-01-01

Understanding of the interactions between estradiol (E2) and insulin-like growth factor-I (IGF-I) is still incomplete. Cell lines derived from the MCF-7 breast cancer cells were generated with suppressed expression of the IGF-I receptor (IGF-IR), termed IGF-IR.low cells, by stable transfection using small interfering RNA (siRNA) expression vector. Vector for control cells carried sequence generating non-interfering RNA. Concomitant with reduction in the IGF-IR levels, the IGF-IR.low cells also showed a reduction in estrogen receptor α (ERα) and progesterone receptor expressions and an elevation in the expression of ERβ. The number of the IGF-IR.low cells was reduced in response to IGF-I and human growth hormone plus epidermal growth factor, but E2 did not cause increase in the number of the IGF-IR.low cells compared to controls. Proliferation rate of IGF-IR.low cells was only reduced in response to E2 compared to controls, whereas their basal and hormone stimulated apoptosis rate was increased. Phosphorylation of p38 mitogen activated protein kinase (p38 MAPK) was increased in the IGF-IR.low cells after treatment with E2, without affecting control cells. Further, phosphorylation of the tumor suppressor protein p53 was elevated in the IGF-IR.low cells compared to the controls. Summary, suppressing the IGF-IR expression decreased the level of ERα but increased the level of ERβ. Overall growth rate of the IGF-IR.low cells was reduced mostly through an increase in apoptosis without affecting proliferation substantially. We hypothesize that a decreased ERα:ERβ ratio triggered a rapid phosphorylation of p38 MAPK which in turn phosphorylated the p53 tumor suppressor and accelerated apoptosis rate. PMID:20974640

In Vitro Killing of Colorectal Carcinoma Cells by Autologous Activated NK Cells is Boosted by Anti-Epidermal Growth Factor Receptor-induced ADCC Regardless of RAS Mutation Status.

PubMed

Turin, Ilaria; Delfanti, Sara; Ferulli, Federica; Brugnatelli, Silvia; Tanzi, Matteo; Maestri, Marcello; Cobianchi, Lorenzo; Lisini, Daniela; Luinetti, Ombretta; Paulli, Marco; Perotti, Cesare; Todisco, Elisabetta; Pedrazzoli, Paolo; Montagna, Daniela

2018-05-01

Treatment of advanced metastatic colorectal cancer (mCRC) patients is associated with a poor prognosis and significant morbidity. Moreover, targeted therapies such as anti-epidermal growth factor receptor (EGFR) have no effect in metastatic patients with tumors harboring a mutation in the RAS gene. The failure of conventional treatment to improve outcomes in mCRC patients has prompted the development of adoptive immunotherapy approaches including natural killer (NK)-based therapies. In this study, after confirmation that patients' NK cells were not impaired in their cytotoxic activity, evaluated against long-term tumor cell lines, we evaluated their interactions with autologous mCRC cells. Molecular and phenotypical evaluation of mCRC cells, expanded in vitro from liver metastasis, showed that they expressed high levels of polio virus receptor and Nectin-2, whereas UL16-binding proteins were less expressed in all tumor samples evaluated. Two different patterns of MICA/B and HLA class I expression on the membrane of mCRC were documented; approximately half of mCRC patients expressed high levels of these molecules on the membrane surface, whereas, in the remaining, very low levels were documented. Resting NK cells were unable to display sizeable levels of cytotoxic activity against mCRC cells, whereas their cytotoxic activity was enhanced after overnight or 5-day incubation with IL-2 or IL-15. The susceptibility of NK-mediated mCRC lysis was further significantly enhanced after coating with cetuximab, irrespective of their RAS mutation and HLA class I expression. These data open perspectives for combined NK-based immunotherapy with anti-epidermal growth factor receptor antibodies in a cohort of mCRC patients with a poor prognosis refractory to conventional therapies.

Immunolocalization of Substance P and NK-1 Receptor in ADIPOSE Stem Cells.

PubMed

Muñoz, Miguel; Muñoz, Mario F; Ayala, Antonio

2017-12-01

Substance P (SP) is a neuropeptide belonging to the thachykinin peptide family. SP, after binding to its receptor, the neurokinin 1 receptor (NK1R), controls several transcription factors such as NF-κB, hypoxia inducible factor (HIF-1α), c-myc, c-fos, c-jun, and AP-1. SP and NK1R have a widespread distribution in both the central and peripheral nervous systems. They are also present in cells not belonging to the nervous system (immune cells, placenta, etc.). SP is located in all body fluids, that is, blood, cerebrospinal fluid, etc., making it ubiquitous throughout the human body. SP and NK1R genes are expressed in the stem cell line TF-1 and in primary stem cells derived from human placental cord blood. However, to our knowledge, the presence of SP and the NK1R receptor in adipose stem cells (ADSC) is unknown. We demonstrated by immunofluorescence the localization of SP and NK1R in human and rat ADSC. SP and NK1R are located in both the cytoplasm and the nucleus of these cells. The NK1R is higher in the nucleus than in the cytoplasm of ADSCs. By Western blot we demonstrated the presence of different isoforms of NK1R that have different subcellular locations in the ADSC. SP induces proliferation and mitogenesis through NK1R in ADSCs. These findings reported here for the first time suggest an important role for a SP/NK1R system, either as genetic and/or epigenetic factor, in both the cytoplasm and nucleus functions of the ADSCs. J. Cell. Biochem. 118: 4686-4696, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Vascular Consequences of Aldosterone Excess and Mineralocorticoid Receptor Antagonism.

PubMed

Chrissobolis, Sophocles

2017-01-01

Aldosterone binds to mineralocorticoid receptors (MRs) on renal epithelial cells to regulate sodium and water reabsorption, and therefore blood pressure. Recently, the actions of aldosterone outside the kidney have been extensively investigated, with numerous reports of aldosterone having detrimental actions, including in the vasculature. Notably, elevated aldosterone levels are an independent cardiovascular risk factor, and in addition to causing an increase in blood pressure, aldosterone can have blood pressure-dependent and -independent effects commonly manifested in the vasculature in cardiovascular diseases, including oxidative stress, endothelial dysfunction, inflammation, remodeling, stiffening, and plaque formation. Receptor-dependent mechanisms mediating these actions include the MR expressed on vascular endothelial and smooth muscle cells, but also include the angiotensin II type 1 receptor, epidermal growth factor receptor and vascular endothelial growth factor receptor 1, with downstream mechanisms including NADPH oxidase, cyclooxygenase, glucose-6-phosphate dehydrogenase, poly-(ADP ribose) polymerase and placental growth factor. The beneficial actions of MR antagonism in experimental hypertension include improved endothelial function, reduced hypertrophy and remodeling, and in atherosclerosis beneficial actions include reduced plaque area, inflammation, oxidative stress and endothelial dysfunction. Aldosterone excess is detrimental and MR antagonism is beneficial in humans also. The emerging concept of the contribution of aldosterone/MR-induced immunity to vascular pathology will also be discussed. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

The IL-6 receptor super-antagonist Sant7 enhances antiproliferative and apoptotic effects induced by dexamethasone and zoledronic acid on multiple myeloma cells.

PubMed

Tassone, Pierfrancesco; Galea, Eulalia; Forciniti, Samantha; Tagliaferri, Pierosandro; Venuta, Salvatore

2002-10-01

Interleukin-6 (IL-6) is the major growth and survival factor for multiple myeloma (MM), and has been shown to protect MM cells from apoptosis induced by a variety of agents. IL-6 receptor antagonists, which prevent the assembly of functional IL-6 receptor complexes, inhibit cell proliferation and induce apoptosis in MM cells. We have investigated whether the IL-6 receptor super-antagonist Sant7 might enhance the antiproliferative and apoptotic effects induced by the combination of dexamethasone (Dex) and zoledronic acid (Zln) on human MM cell lines and primary cells from MM patients. Here we show that each of these compounds individually induced detectable antiproliferative effects on MM cells. Sant7 significantly enhanced growth inhibition and apoptosis induced by Dex and Zln on both MM cell lines and primary MM cells. These results indicate that overcoming IL-6 mediated cell resistance by Sant7 potentiates the effect of glucocorticoides and bisphosphonates on MM cell growth and survival, providing a rationale for therapies including IL-6 antagonists in MM.

Activation of PPARbeta/delta induces endothelial cell proliferation and angiogenesis.

PubMed

Piqueras, Laura; Reynolds, Andrew R; Hodivala-Dilke, Kairbaan M; Alfranca, Arántzazu; Redondo, Juan M; Hatae, Toshihisa; Tanabe, Tadashi; Warner, Timothy D; Bishop-Bailey, David

2007-01-01

The role of the nuclear receptor peroxisome-proliferator activated receptor (PPAR)-beta/delta in endothelial cells remains unclear. Interestingly, the selective PPARbeta/delta ligand GW501516 is in phase II clinical trials for dyslipidemia. Here, using GW501516, we have assessed the involvement of PPARbeta/delta in endothelial cell proliferation and angiogenesis. Western blot analysis indicated PPARbeta/delta was expressed in primary human umbilical and aortic endothelial cells, and in the endothelial cell line, EAHy926. Treatment with GW501516 increased human endothelial cell proliferation and morphogenesis in cultures in vitro, endothelial cell outgrowth from murine aortic vessels in vitro, and angiogenesis in a murine matrigel plug assay in vivo. GW501516 induced vascular endothelial cell growth factor mRNA and peptide release, as well as adipose differentiation-related protein (ADRP), a PPARbeta/delta target gene. GW501516-induced proliferation, morphogenesis, vascular endothelial growth factor (VEGF), and ADRP were absent in endothelial cells transfected with dominant-negative PPARbeta/delta. Furthermore, treatment of cells with cyclo-VEGFI, a VEGF receptor1/2 antagonist, abolished GW501516-induced endothelial cell proliferation and tube formation. PPARbeta/delta is a novel regulator of endothelial cell proliferation and angiogenesis through VEGF. The use of GW501516 to treat dyslipidemia may need to be carefully monitored in patients susceptible to angiogenic disorders.

Fibroblast Growth Factor 2: An Epithelial Ductal Cell Growth Inhibitor That Drops Out in Breast Cancer

DTIC Science & Technology

2011-10-01

fibroblast   growth   factor   receptors  and  their  prognostic...AD_________________ Award Number: W81XWH-08-1-0708 TITLE: Fibroblast Growth Factor 2: an...September 2008 – 14 September 2011 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Fibroblast Growth Factor 2: an Epithelial Ductal Cell Growth

Epidermal growth factor receptor expression is related to post-mitotic events in cerebellar development: regulation by thyroid hormone.

PubMed

Carrasco, Emilce; Blum, Mariann; Weickert, Cynthia Shannon; Casper, Diana

2003-01-10

It has been established that thyroid hormone and neurotrophic factors both orchestrate developmental events in the brain. However, it is not clear how these two influences are related. In this study, we investigated the effects of thyroid hormone on cerebellar development and the coincident expression of transforming growth factor-alpha (TGF-alpha), a ligand in the epidermal growth factor (EGF) family, and the epidermal growth factor receptor (EGFR). Profiles of thyroid hormone expression were measured in postnatal animals and were found to peak at postnatal day 15 (P15). These levels dropped below detectable levels when mice were made hypothyroid with propylthiouracil (PTU). TGF-alpha and EGFR expression, as determined by RNAse protection assay, was maximal at P6 in normal animals, but remained low in hypothyroid animals, suggesting that thyroid hormone was responsible for their induction. In situ hybridization and immunohistochemical analysis of EGFR expression revealed that this receptor was present on granule cells within the inner zone of the external granule cell layer (EGL), suggesting that EGFR-ligands were not inducing granule cell proliferation. The persistence of EGFR expression on migrating granule cells and subsequent down-regulation of expression in the internal granule cell layer (IGL) implicates a role for EGFR-ligands in differentiation and/or migration. In hypothyroid animals, we observed a delayed progression of granule cell migration, consistent with the persistence of EGFR labeling in the EGL, and in the 'pile-up' of labeled cells at the interface between the molecular layer and the Purkinje cell layer. Taken together, these results implicate thyroid hormone in the coordinated expression of TGF-alpha and EGFR, which are positioned to play a role in post-mitotic developmental events in the cerebellum.

Microenvironment interactions and B-cell receptor signaling in Chronic Lymphocytic Leukemia: implications for disease pathogenesis and treatment

PubMed Central

ten Hacken, Elisa; Burger, Jan A.

2015-01-01

Chronic Lymphocytic Leukemia (CLL) is a malignancy of mature B lymphocytes which are highly dependent on interactions with the tissue microenvironment for their survival and proliferation. Critical components of the microenvironment are monocyte-derived nurselike cells (NLCs), mesenchymal stromal cells, T cells and NK cells, which communicate with CLL cells through a complex network of adhesion molecules, chemokine receptors, tumor necrosis factor (TNF) family members, and soluble factors. (Auto-) antigens and/or autonomous mechanisms activate the B-cell receptor (BCR) and its downstream signaling cascade in secondary lymphatic tissues, playing a central pathogenetic role in CLL. Novel small molecule inhibitors, including the Bruton’s tyrosine kinase (BTK) inhibitor ibrutinib and the phosphoinositide-3-kinase delta (PI3Kδ) inhibitor idelalisib, target BCR signaling and have become the most successful new therapeutics in this disease. We here review the cellular and molecular characteristics of CLL cells, and discuss the cellular components and key pathways involved in the cross-talk with their microenvironment. We also highlight the relevant novel treatment strategies, focusing on immunomodulatory agents and BCR signaling inhibitors and how these treatments disrupt CLL-microenvironment interactions. PMID:26193078

Tissue kallikrein induces SH-SY5Y cell proliferation via epidermal growth factor receptor and extracellular signal-regulated kinase1/2 pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Zhengyu; Department of Neurology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200437; Yang, Qi

2014-03-28

Highlights: • TK promotes EGFR phosphorylation in SH-SY5Y cells. • TK activates ERK1/2 and p38 phosphorylation in SH-SY5Y cells. • TK mediates SH-SY5Y cell proliferation via EGFR and ERK1/2 pathway. - Abstract: Tissue kallikrein (TK) is well known to take most of its biological functions through bradykinin receptors. In the present study, we found a novel signaling pathway mediated by TK through epidermal growth factor receptor (EGFR) in human SH-SY5Y cells. We discovered that TK facilitated the activation of EGFR, extracellular signal-regulated kinase (ERK) 1/2 and p38 cascade. Interestingly, not p38 but ERK1/2 phosphorylation was severely compromised in cells depletedmore » of EGFR. Nevertheless, impairment of signaling of ERK1/2 seemed not to be restricted to EGFR phosphorylation. We also observed that TK stimulation could induce SH-SY5Y cell proliferation, which was reduced by EGFR down-regulation or ERK1/2 inhibitor. Overall, our findings provided convincing evidence that TK could mediate cell proliferation via EGFR and ERK1/2 pathway in vitro.« less

Cooperation of neurotrophin receptor TrkB and Her2 in breast cancer cells facilitates brain metastases.

PubMed

Choy, Cecilia; Ansari, Khairul I; Neman, Josh; Hsu, Sarah; Duenas, Matthew J; Li, Hubert; Vaidehi, Nagarajan; Jandial, Rahul

2017-04-26

Patients with primary breast cancer that is positive for human epidermal growth factor receptor 2 (Her2+) have a high risk of developing metastases in the brain. Despite gains with systemic control of Her2+ disease using molecular therapies, brain metastases remain recalcitrant to therapeutic discovery. The clinical predilection of Her2+ breast cancer cells to colonize the brain likely relies on paracrine mechanisms. The neural niche poses unique selection pressures, and neoplastic cells that utilize the brain microenvironment may have a survival advantage. Tropomyosin-related kinase B (TrkB), Her2, and downstream targets were analyzed in primary breast cancer, breast-to-brain metastasis (BBM) tissues, and tumor-derived cell lines using quantitative real-time PCR, western blot, and immunohistochemical assessment. TrkB function on BBM was confirmed with intracranial, intracardiac, or mammary fat pad xenografts in non-obese diabetic/severe combined immunodeficiency mice. The function of brain-derived neurotrophic factor (BDNF) on cell proliferation and TrkB/Her2 signaling and interactions were confirmed using selective shRNA knockdown and selective inhibitors. The physical interaction of Her2-TrkB was analyzed using electron microscopy, co-immunoprecipitation, and in silico analysis. Dual targeting of Her2 and TrkB was analyzed using clinically utilized treatments. We observed that patient tissues and cell lines derived from Her2+ human BBM displayed increased activation of TrkB, a neurotrophin receptor. BDNF, an extracellular neurotrophin, with roles in neuronal maturation and homeostasis, specifically binds to TrkB. TrkB knockdown in breast cancer cells led to decreased frequency and growth of brain metastasis in animal models, suggesting that circulating breast cancer cells entering the brain may take advantage of paracrine BDNF-TrkB signaling for colonization. In addition, we investigated a possible interaction between TrkB and Her2 receptors on brain metastatic breast cancer cells, and found that BDNF phosphorylated both its cognate TrkB receptor and the Her2 receptor in brain metastatic breast cancer cells. Collectively, our findings suggest that heterodimerization of Her2 and TrkB receptors gives breast cancer cells a survival advantage in the brain and that dual inhibition of these receptors may hold therapeutic potential.

Insulin receptor-related receptor as an extracellular pH sensor involved in the regulation of acid-base balance.

PubMed

Petrenko, Alexander G; Zozulya, Sergey A; Deyev, Igor E; Eladari, Dominique

2013-10-01

Recent studies of insulin receptor-related receptor (IRR) revealed its unusual property to activate upon extracellular application of mildly alkaline media, pH>7.9. The activation of IRR with hydroxyl anion has typical features of ligand-receptor interaction; it is specific, dose-dependent, involves the IRR extracellular domain and is accompanied by a major conformational change. IRR is a member of the insulin receptor minifamily and has been long viewed as an orphan receptor tyrosine kinase since no peptide or protein agonist of IRR was found. In the evolution, IRR is highly conserved since its divergence from the insulin and insulin-like growth factor receptors in amphibia. The latter two cannot be activated by alkali. Another major difference between them is that unlike ubiquitously expressed insulin and insulin-like growth factor receptors, IRR is found in specific sets of cells of only some tissues, most of them being exposed to extracorporeal liquids of extreme pH. In particular, largest concentrations of IRR are in beta-intercalated cells of the kidneys. The primary physiological function of these cells is to excrete excessive alkali as bicarbonate into urine. When IRR is removed genetically, animals loose the property to excrete bicarbonate upon experimentally induced alkalosis. In this review, we will discuss the available in vitro and in vivo data that support the hypothesis of IRR role as a physiological alkali sensor that regulates acid-base balance. This article is part of a Special Issue entitled: Emerging recognition and activation mechanisms of receptor tyrosine kinases. Copyright © 2012 Elsevier B.V. All rights reserved.

Generation of herpesvirus entry mediator (HVEM)-restricted herpes simplex virus type 1 mutant viruses: resistance of HVEM-expressing cells and identification of mutations that rescue nectin-1 recognition.

PubMed

Uchida, Hiroaki; Shah, Waris A; Ozuer, Ali; Frampton, Arthur R; Goins, William F; Grandi, Paola; Cohen, Justus B; Glorioso, Joseph C

2009-04-01

Both initial infection and cell-to-cell spread by herpes simplex virus type 1 (HSV-1) require the interaction of the viral glycoprotein D (gD) with an entry receptor on the cell surface. The two major HSV entry receptors, herpesvirus entry mediator (HVEM) and nectin-1, mediate infection independently but are coexpressed on a variety of cells. To determine if both receptors are active in these instances, we have established mutant viruses that are selectively impaired for recognition of one or the other receptor. In plaque assays, these viruses showed approximately 1,000-fold selectivity for the matched receptor over the mismatched receptor. Separate assays showed that each virus is impaired for both infection and spread through the mismatched receptor. We tested several human tumor cell lines for susceptibility to these viruses and observed that HT29 colon carcinoma cells are susceptible to infection by nectin-1-restricted virus but are highly resistant to HVEM-restricted virus infection, despite readily detectable HVEM expression on the cell surface. HVEM cDNA isolated from HT29 cells rendered HSV-resistant cells permissive for infection by the HVEM-restricted virus, suggesting that HT29 cells lack a cofactor for HVEM-mediated infection or express an HVEM-specific inhibitory factor. Passaging of HVEM-restricted virus on nectin-1-expressing cells yielded a set of gD missense mutations that each restored functional recognition of nectin-1. These mutations identify residues that likely play a role in shaping the nectin-1 binding site of gD. Our findings illustrate the utility of these receptor-restricted viruses in studying the early events in HSV infection.

Roles of purinergic P2X7 receptor in glioma and microglia in brain tumors.

PubMed

McLarnon, James G

2017-08-28

This review considers evidence suggesting that activation of the ionotropic purinergic receptor P2X 7 (P2X 7 R) is a contributing factor in the growth of brain tumors. Importantly, expression of P2X 7 R may be upregulated in both glioma cells and in immune responding microglial cells with possible differential effects on tumor progression. The recruitment of immune cells into tumor regions may not only be involved in supporting an immunosuppressive environment aiding tumor growth but activated microglia could secrete inflammatory factors promoting neoangiogenesis in expanding tumors. The subtype P2X 7 R exhibits a number of unique properties including activation of the receptor in pathological conditions associated with developing brain tumors. In particular, the tumor microenvironment includes elevated levels of ATP required for activation of P2X 7 R and the sustained tumor and immune cell P2X 7 R-mediated responses which in total contribute to overall tumor growth and viability. Studies on cultured rat and human glioma show marked increases in expression of P2X 7 R and enhanced cell mobility relative to control. Glioma cell animal models demonstrate enhanced expression of P2X 7 R in both glioma and microglia with antagonism of receptor showing differential effects on tumor growth. Overall, P2X 7 R activation is associated with a complexity of modulatory actions on tumor growth in part due to ubiquitous expression of the receptor in glioma and immune responsive cells. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Neuron-to-glia signaling mediated by excitatory amino acid receptors regulates ErbB receptor function in astroglial cells of the neuroendocrine brain.

PubMed

Dziedzic, Barbara; Prevot, Vincent; Lomniczi, Alejandro; Jung, Heike; Cornea, Anda; Ojeda, Sergio R

2003-02-01

Hypothalamic astroglial erbB tyrosine kinase receptors are required for the timely initiation of mammalian puberty. Ligand-dependent activation of these receptors sets in motion a glia-to-neuron signaling pathway that prompts the secretion of luteinizing hormone-releasing hormone (LHRH), the neuropeptide controlling sexual development, from hypothalamic neuroendocrine neurons. The neuronal systems that may regulate this growth factor-mediated back signaling to neuroendocrine neurons have not been identified. Here we demonstrate that hypothalamic astrocytes contain metabotropic receptors of the metabotropic glutamate receptor 5 subtype and the AMPA receptor subunits glutamate receptor 2 (GluR2) and GluR3. As in excitatory synapses, these receptors are in physical association with their respective interacting/clustering proteins Homer and PICK1. In addition, they are associated with erbB-1 and erbB-4 receptors. Concomitant activation of astroglial metabotropic and AMPA receptors results in the recruitment of erbB tyrosine kinase receptors and their respective ligands to the glial cell membrane, transactivation of erbB receptors via a mechanism requiring metalloproteinase activity, and increased erbB receptor gene expression. By facilitating erbB-dependent signaling and promoting erbB receptor gene expression in astrocytes, a neuron-to-glia glutamatergic pathway may represent a basic cell-cell communication mechanism used by the neuroendocrine brain to coordinate the facilitatory transsynaptic and astroglial input to LHRH neurons during sexual development.

Angiogenesis and Vascular Architecture in Pheochromocytomas

PubMed Central

Favier, Judith; Plouin, Pierre-François; Corvol, Pierre; Gasc, Jean-Marie

2002-01-01

Angiogenesis is a critical step in tumor growth and metastatic invasion. We here report the study of the vascular status of 10 benign and 9 malignant pheochromocytomas. We examined the vascular architecture after immunostaining endothelial cells (CD34) and vascular smooth muscle cells (α-actin) and identified a vascular pattern characteristic of malignant lesions. To define a gene expression profile indicative of the invasive phenotype, we studied by in situ hybridization the expression of genes encoding several pro- and anti-angiogenic factors [hypoxia-inducible factor (HIF-1α), EPAS1, vascular endothelial growth factor (VEGF), VEGF receptors, angiopoietins and their receptor Tie2, five genes of the endothelin system, and thrombospondin 1]. A semiquantitative evaluation of the labeling revealed an induction of genes encoding EPAS1, VEGF, VEGFR-1, VEGFR-2, endothelin receptor, type B (ETB) and endothelin receptor, type A (ETA) in malignant pheochromocytomas as compared to benign tumors. These differences were observed in tumor cells, in endothelial cells, or in both. Quantification by real-time reverse-transcriptase polymerase chain reaction showed an increase of EPAS1, VEGF, and ETB transcripts of 4.5-, 3.5-, and 10-fold, respectively, in malignant versus benign tumors. Furthermore, we observed a strong correlation between the expression of EPAS1 and VEGF in tumoral tissue and between EPAS1 and ETB in endothelial cells. Altogether, our observations show that analysis of angiogenesis provides promising new criteria for the diagnosis of malignant pheochromocytomas. PMID:12368197

Mature brain-derived neurotrophic factor and its receptor TrkB are upregulated in human glioma tissues.

PubMed

Xiong, Jing; Zhou, L I; Lim, Yoon; Yang, Miao; Zhu, Yu-Hong; Li, Zhi-Wei; Fu, Deng-Li; Zhou, Xin-Fu

2015-07-01

There are two forms of brain-derived neurotrophic factor (BDNF), precursor of BDNF (proBDNF) and mature BDNF, which each exert opposing effects through two different transmembrane receptor signaling systems, consisting of p75 neurotrophin receptor (p75NTR) and tyrosine receptor kinase B (TrkB). Previous studies have demonstrated that proBDNF promotes cell death and inhibits the growth and migration of C6 glioma cells through p75NTR in vitro , while mature BDNF has opposite effects on C6 glioma cells. It is hypothesized that mature BDNF is essential in the development of malignancy in gliomas. However, histological data obtained in previous studies were unable distinguish mature BDNF from proBDNF due to the lack of specific antibodies. The present study investigated the expression of mature BDNF using a specific sheep monoclonal anti-mature BDNF antibody in 42 human glioma tissues of different grades and 10 control tissues. The correlation between mature BDNF and TrkB was analyzed. Mature BDNF expression was significantly increased in high-grade gliomas, and was positively correlated with the malignancy of the tumor and TrkB receptor expression. The present data have demonstrated that increased levels of mature BDNF contribute markedly to the development of malignancy of human gliomas through the primary BDNF receptor TrkB.

Expression dynamics of self-renewal factors for spermatogonial stem cells in the mouse testis.

PubMed

Sakai, Mizuki; Masaki, Kaito; Aiba, Shota; Tone, Masaaki; Takashima, Seiji

2018-04-16

Glial cell line-derived neurotrophic factor (GDNF) and fibroblast growth factor 2 (FGF2) are bona fide self-renewal factors for spermatogonial stem cells (SSCs). Although GDNF is indispensable for the maintenance of SSCs, the role of FGF2 in the testis remains to be elucidated. To clarify this, the expression dynamics and regulatory mechanisms of Fgf2 and Gdnf in the mouse testes were analyzed. It is well known that Sertoli cells express Gdnf, and its receptor is expressed in a subset of undifferentiated spermatogonia, including SSCs. However, we found that Fgf2 was mainly expressed in the germ cells and its receptors were expressed not only in the cultured spermatogonial cell line, but also in testicular somatic cells. Aging, hypophysectomy, retinoic acid treatment, and testicular injury induced distinct Fgf2 and Gdnf expression dynamics, suggesting a difference in the expression mechanism of Fgf2 and Gdnf in the testis. Such differences might cause a dynamic fluctuation of Gdnf/Fgf2 ratio depending on the intrinsic/extrinsic cues. Considering that FGF2-cultured spermatogonia exhibit more differentiated phenotype than those cultured with GDNF, FGF2 might play a role distinct from that of GDNF in the testis, despite the fact that both factors are self-renewal factor for SSC in vitro.

Sorting receptor Rer1 controls surface expression of muscle acetylcholine receptors by ER retention of unassembled alpha-subunits.

PubMed

Valkova, Christina; Albrizio, Marina; Röder, Ira V; Schwake, Michael; Betto, Romeo; Rudolf, Rüdiger; Kaether, Christoph

2011-01-11

The nicotinic acetylcholine receptor of skeletal muscle is composed of five subunits that are assembled in a stepwise manner. Quality control mechanisms ensure that only fully assembled receptors reach the cell surface. Here, we show that Rer1, a putative Golgi-ER retrieval receptor, is involved in the biogenesis of acetylcholine receptors. Rer1 is expressed in the early secretory pathway in the myoblast line C2C12 and in mouse skeletal muscle, and up-regulated during myogenesis. Upon down-regulation of Rer1 in C2C12 cells, unassembled acetylcholine receptor α-subunits escape from the ER and are transported to the plasma membrane and lysosomes, where they are degraded. As a result, the amount of fully assembled receptor at the cell surface is reduced. In vivo Rer1 knockdown and genetic inactivation of one Rer1 allele lead to significantly smaller neuromuscular junctions in mice. Our data show that Rer1 is a functionally important unique factor that controls surface expression of muscle acetylcholine receptors by localizing unassembled α-subunits to the early secretory pathway.

Prox1 and fibroblast growth factor receptors form a novel regulatory loop controlling lens fiber differentiation and gene expression

PubMed Central

Audette, Dylan S.; Anand, Deepti; So, Tammy; Rubenstein, Troy B.; Lachke, Salil A.; Lovicu, Frank J.; Duncan, Melinda K.

2016-01-01

Lens epithelial cells differentiate into lens fibers (LFs) in response to a fibroblast growth factor (FGF) gradient. This cell fate decision requires the transcription factor Prox1, which has been hypothesized to promote cell cycle exit in differentiating LF cells. However, we find that conditional deletion of Prox1 from mouse lenses results in a failure in LF differentiation despite maintenance of normal cell cycle exit. Instead, RNA-seq demonstrated that Prox1 functions as a global regulator of LF cell gene expression. Intriguingly, Prox1 also controls the expression of fibroblast growth factor receptors (FGFRs) and can bind to their promoters, correlating with decreased downstream signaling through MAPK and AKT in Prox1 mutant lenses. Further, culturing rat lens explants in FGF increased their expression of Prox1, and this was attenuated by the addition of inhibitors of MAPK. Together, these results describe a novel feedback loop required for lens differentiation and morphogenesis, whereby Prox1 and FGFR signaling interact to mediate LF differentiation in response to FGF. PMID:26657765

Fibroblast growth factor 5-short (FGF5s) inhibits the activity of FGF5 in primary and secondary hair follicle dermal papilla cells of cashmere goats.

PubMed

He, Xiaolin; Chao, Yuan; Zhou, Guangxian; Chen, Yulin

2016-01-10

To determine the relationship between fibroblast growth factor 5 (FGF5) and FGF5-short (FGF5s) in dermal papilla cells of cashmere goat primary and secondary hair follicles. We isolated dermal papilla cells from primary hair follicle (PHF) and secondary hair follicle (SHF) of cashmere goat, and found that the FGF5 receptor, fibroblast growth factor receptor 1 (FGFR1), was expressed in these two types of dermal papilla cells. Moreover, adenovirus-mediated overexpression of FGF5 could upregulate the mRNA expression of insulin-like growth factor-1 (IGF-1), versican and noggin that were important for follicle growth maintenance, whereas downregulate the expression of anagen chalone bone morphogenetic protein 4 (BMP4) in dermal papilla cells. However, these alterations were partly reversed by FGF5s overexpression. In conclusion, our results demonstrated that FGF5s acted as an inhibitor of FGF5 in the regulation of anagen-catagen transition of cashmere goat dermal papilla cells. Copyright © 2015 Elsevier B.V. All rights reserved.

Prox1 and fibroblast growth factor receptors form a novel regulatory loop controlling lens fiber differentiation and gene expression.

PubMed

Audette, Dylan S; Anand, Deepti; So, Tammy; Rubenstein, Troy B; Lachke, Salil A; Lovicu, Frank J; Duncan, Melinda K

2016-01-15

Lens epithelial cells differentiate into lens fibers (LFs) in response to a fibroblast growth factor (FGF) gradient. This cell fate decision requires the transcription factor Prox1, which has been hypothesized to promote cell cycle exit in differentiating LF cells. However, we find that conditional deletion of Prox1 from mouse lenses results in a failure in LF differentiation despite maintenance of normal cell cycle exit. Instead, RNA-seq demonstrated that Prox1 functions as a global regulator of LF cell gene expression. Intriguingly, Prox1 also controls the expression of fibroblast growth factor receptors (FGFRs) and can bind to their promoters, correlating with decreased downstream signaling through MAPK and AKT in Prox1 mutant lenses. Further, culturing rat lens explants in FGF increased their expression of Prox1, and this was attenuated by the addition of inhibitors of MAPK. Together, these results describe a novel feedback loop required for lens differentiation and morphogenesis, whereby Prox1 and FGFR signaling interact to mediate LF differentiation in response to FGF. © 2016. Published by The Company of Biologists Ltd.

Molecular pathways mediating differential responses to lipopolysaccharide between human and baboon arterial endothelial cells.

PubMed

Shi, Qiang; Cox, Laura A; Glenn, Jeremy; Tejero, Maria E; Hondara, Vida; Vandeberg, John L; Wang, Xing Li

2010-02-01

1. Vascular inflammation plays a critical role in atherogenesis. Previously, we showed that baboon arterial endothelial cells (BAEC) were hyporesponsive to lipopolysaccharide (LPS) compared with human arterial endothelial cells (HAEC). 2. In the present study, we investigated mechanisms underlying differential responses between HAEC and BAEC to tumour necrosis factor (TNF)-alpha and LPS. 3. Both HAEC and BAEC responded similarly to TNF-alpha. However, BAEC showed retarded responses to LPS in expression of E-selectin, intercellular adhesion molecule-1, monocyte chemotactic protein-1 and interleukin-8 (P < 0.05). These changes were confirmed at the mRNA level. Tumour necrosis factor-alpha activated nuclear factor-kappaB members such as p50, p52, p65, c-rel and RelB in both HAEC and BAEC. In contrast, LPS activated p50 and p65 only in HAEC. Using microarray assays, we found that TNF receptor-associated factor 2 (TRAF-2), TNF receptor superfamily, member 1A-associated via death domain (TRADD) and nuclear factors such as nuclear factor of kappa in B-cells inhibitor, alpha (NFKBIA) and nuclear factor of kappa in B-cells inhibitor, beta (NFKBIB) were upregulated by LPS only in HAEC. Although the baseline expression of Toll-like receptor (TLR) 4 was low in both HAEC and BAEC, TNF-alpha activated TLR4 expression in both cell types. Although LPS increased TLR4 expression only in HAEC, human and baboon peripheral blood mononuclear cells exhibited similar TLR4 expression and response to LPS. Transfecting BAEC with TLR4/myeloid differentiation protein-2 overexpression vector conferred BAEC responsiveness to LPS. 4. The findings of the present study indicate that an altered TLR4 system may be responsible for the resistance of baboon endothelial cells to LPS. Given the importance of TLR4 in human immune responses and vascular diseases, the natural resistance of baboons to LPS/TLR4-initiated inflammation could make the baboon a valuable animal model in which to study how inflammation affects atherogenesis.

Cell Proliferation and Epidermal Growth Factor Signaling in Non-small Cell Lung Adenocarcinoma Cell Lines Are Dependent on Rin1

PubMed Central

Tomshine, Jin C.; Severson, Sandra R.; Wigle, Dennis A.; Sun, Zhifu; Beleford, Daniah A. T.; Shridhar, Vijayalakshmi; Horazdovsky, Bruce F.

2009-01-01

Rin1 is a Rab5 guanine nucleotide exchange factor that plays an important role in Ras-activated endocytosis and growth factor receptor trafficking in fibroblasts. In this study, we show that Rin1 is expressed at high levels in a large number of non-small cell lung adenocarcinoma cell lines, including Hop62, H650, HCC4006, HCC827, EKVX, HCC2935, and A549. Rin1 depletion from A549 cells resulted in a decrease in cell proliferation that was correlated to a decrease in epidermal growth factor receptor (EGFR) signaling. Expression of wild type Rin1 but not the Rab5 guanine nucleotide exchange factor-deficient Rin1 (Rin1Δ) complemented the Rin1 depletion effects, and overexpression of Rin1Δ had a dominant negative effect on cell proliferation. Rin1 depletion stabilized the cell surface levels of EGFR, suggesting that internalization was necessary for robust signaling in A549 cells. In support of this conclusion, introduction of either dominant negative Rab5 or dominant negative dynamin decreased A549 proliferation and EGFR signaling. These data demonstrate that proper internalization and endocytic trafficking are critical for EGFR-mediated signaling in A549 cells and suggest that up-regulation of Rin1 in A549 cell lines may contribute to their proliferative nature. PMID:19570984

Targeting NK-1 Receptors to Prevent and Treat Pancreatic Cancer: A New Therapeutic Approach

PubMed Central

Muñoz, Miguel; Coveñas, Rafael

2015-01-01

Pancreatic cancer (PC) is the fourth leading cause of cancer related-deaths in both men and women, and the 1- and 5-year relative survival rates are 25% and 6%, respectively. It is known that smoking, alcoholism and psychological stress are risk factors that can promote PC and increase PC progression. To date, the prevention of PC is crucial because there is no curative treatment. After binding to the neurokinin-1 (NK-1) receptor (a receptor coupled to the stimulatory G-protein Gαs that activates adenylate cyclase), the peptide substance P (SP)—at high concentrations—is involved in many pathophysiological functions, such as depression, smoking, alcoholism, chronic inflammation and cancer. It is known that PC cells and samples express NK-1 receptors; that the NK-1 receptor is overexpressed in PC cells in comparison with non-tumor cells, and that nanomolar concentrations of SP induce PC cell proliferation. By contrast, NK-1 receptor antagonists exert antidepressive, anxiolytic and anti-inflammatory effects and anti-alcohol addiction. These antagonists also exert an antitumor action since in vitro they inhibit PC cell proliferation (PC cells death by apoptosis), and in a xenograft PC mouse model they exert both antitumor and anti-angiogenic actions. NK-1 receptor antagonists could be used for the treatment of PC and hence the NK-1 receptor could be a new promising therapeutic target in PC. PMID:26154566

Identification of the functional interleukin-22 (IL-22) receptor complex: the IL-10R2 chain (IL-10Rbeta ) is a common chain of both the IL-10 and IL-22 (IL-10-related T cell-derived inducible factor, IL-TIF) receptor complexes.

PubMed

Kotenko, S V; Izotova, L S; Mirochnitchenko, O V; Esterova, E; Dickensheets, H; Donnelly, R P; Pestka, S

2001-01-26

Interleukin-10 (IL-10)-related T cell-derived inducible factor (IL-TIF; provisionally designated IL-22) is a cytokine with limited homology to IL-10. We report here the identification of a functional IL-TIF receptor complex that consists of two receptor chains, the orphan CRF2-9 and IL-10R2, the second chain of the IL-10 receptor complex. Expression of the CRF2-9 chain in monkey COS cells renders them sensitive to IL-TIF. However, in hamster cells both chains, CRF2-9 and IL-10R2, must be expressed to assemble the functional IL-TIF receptor complex. The CRF2-9 chain (or the IL-TIF-R1 chain) is responsible for Stat recruitment. Substitution of the CRF2-9 intracellular domain with the IFN-gammaR1 intracellular domain changes the pattern of IL-TIF-induced Stat activation. The CRF2-9 gene is expressed in normal liver and kidney, suggesting a possible role for IL-TIF in regulating gene expression in these tissues. Each chain, CRF2-9 and IL-10R2, is capable of binding IL-TIF independently and can be cross-linked to the radiolabeled IL-TIF. However, binding of IL-TIF to the receptor complex is greater than binding to either receptor chain alone. Sharing of the common IL-10R2 chain between the IL-10 and IL-TIF receptor complexes is the first such case for receptor complexes with chains belonging to the class II cytokine receptor family, establishing a novel paradigm for IL-10-related ligands similar to the shared use of the gamma common chain (gamma(c)) by several cytokines, including IL-2, IL-4, IL-7, IL-9, and IL-15.

Pleiotrophin regulates lung epithelial cell proliferation and differentiation during fetal lung development via beta-catenin and Dlk1.

PubMed

Weng, Tingting; Gao, Li; Bhaskaran, Manoj; Guo, Yujie; Gou, Deming; Narayanaperumal, Jeyaparthasarathy; Chintagari, Narendranath Reddy; Zhang, Kexiong; Liu, Lin

2009-10-09

The role of pleiotrophin in fetal lung development was investigated. We found that pleiotrophin and its receptor, protein-tyrosine phosphatase receptor beta/zeta, were highly expressed in mesenchymal and epithelial cells of the fetal lungs, respectively. Using isolated fetal alveolar epithelial type II cells, we demonstrated that pleiotrophin promoted fetal type II cell proliferation and arrested type II cell trans-differentiation into alveolar epithelial type I cells. Pleiotrophin also increased wound healing of injured type II cell monolayer. Knockdown of pleiotrophin influenced lung branching morphogenesis in a fetal lung organ culture model. Pleiotrophin increased the tyrosine phosphorylation of beta-catenin, promoted beta-catenin translocation into the nucleus, and activated T cell factor/lymphoid enhancer factor transcription factors. Dlk1, a membrane ligand that initiates the Notch signaling pathway, was identified as a downstream target of the pleiotrophin/beta-catenin pathway by endogenous dlk1 expression, promoter assay, and chromatin immunoprecipitation. These results provide evidence that pleiotrophin regulates fetal type II cell proliferation and differentiation via integration of multiple signaling pathways including pleiotrophin, beta-catenin, and Notch pathways.

Peptide receptor targeting in cancer: the somatostatin paradigm.

PubMed

Barbieri, Federica; Bajetto, Adriana; Pattarozzi, Alessandra; Gatti, Monica; Würth, Roberto; Thellung, Stefano; Corsaro, Alessandro; Villa, Valentina; Nizzari, Mario; Florio, Tullio

2013-01-01

Peptide receptors involved in pathophysiological processes represent promising therapeutic targets. Neuropeptide somatostatin (SST) is produced by specialized cells in a large number of human organs and tissues. SST primarily acts as inhibitor of endocrine and exocrine secretion via the activation of five G-protein-coupled receptors, named sst1-5, while in central nervous system, SST acts as a neurotransmitter/neuromodulator, regulating locomotory and cognitive functions. Critical points of SST/SST receptor biology, such as signaling pathways of individual receptor subtypes, homo- and heterodimerization, trafficking, and cross-talk with growth factor receptors, have been extensively studied, although functions associated with several pathological conditions, including cancer, are still not completely unraveled. Importantly, SST exerts antiproliferative and antiangiogenic effects on cancer cells in vitro, and on experimental tumors in vivo. Moreover, SST agonists are clinically effective as antitumor agents for pituitary adenomas and gastro-pancreatic neuroendocrine tumors. However, SST receptors being expressed by tumor cells of various tumor histotypes, their pharmacological use is potentially extendible to other cancer types, although to date no significant results have been obtained. In this paper the most recent findings on the expression and functional roles of SST and SST receptors in tumor cells are discussed.

Inhibiting host-pathogen interactions using membrane-based nanostructures.

PubMed

Bricarello, Daniel A; Patel, Mira A; Parikh, Atul N

2012-06-01

Virulent strains of bacteria and viruses recognize host cells by their plasma membrane receptors and often exploit the native translocation machinery to invade the cell. A promising therapeutic concept for early interruption of pathogen infection is to subvert this pathogenic trickery using exogenously introduced decoys that present high-affinity mimics of cellular receptors. This review highlights emerging applications of molecularly engineered lipid-bilayer-based nanostructures, namely (i) functionalized liposomes, (ii) supported colloidal bilayers or protocells and (iii) reconstituted lipoproteins, which display functional cellular receptors in optimized conformational and aggregative states. These decoys outcompete host cell receptors by preferentially binding to and neutralizing virulence factors of both bacteria and viruses, thereby promising a new approach to antipathogenic therapy. Copyright © 2012 Elsevier Ltd. All rights reserved.

Insulin-Like Growth Factors Are Expressed in the Taste System, but Do Not Maintain Adult Taste Buds

PubMed Central

Biggs, Bradley T.; Tang, Tao; Krimm, Robin F.

2016-01-01

Growth factors regulate cell growth and differentiation in many tissues. In the taste system, as yet unknown growth factors are produced by neurons to maintain taste buds. A number of growth factor receptors are expressed at greater levels in taste buds than in the surrounding epithelium and may be receptors for candidate factors involved in taste bud maintenance. We determined that the ligands of eight of these receptors were expressed in the E14.5 geniculate ganglion and that four of these ligands were expressed in the adult geniculate ganglion. Of these, the insulin-like growth factors (IGF1, IGF2) were expressed in the ganglion and their receptor, insulin-like growth factor receptor 1 (IGF1R), were expressed at the highest levels in taste buds. To determine whether IGF1R regulates taste bud number or structure, we conditionally eliminated IGF1R from the lingual epithelium of mice using the keratin 14 (K14) promoter (K14-Cre::Igf1rlox/lox). While K14-Cre::Igf1rlox/lox mice had significantly fewer taste buds at P30 compared with control mice (Igf1rlox/lox), this difference was not observed by P80. IGF1R removal did not affect taste bud size or cell number, and the number of phospholipase C β2- (PLCβ2) and carbonic anhydrase 4- (Car4) positive taste receptor cells did not differ between genotypes. Taste buds at the back of the tongue fungiform taste field were larger and contained more cells than those at the tongue tip, and these differences were diminished in K14-Cre::Igf1rlox/lox mice. The epithelium was thicker at the back versus the tip of the tongue, and this difference was also attenuated in K14-Cre::Igf1rlox/lox mice. We conclude that, although IGFs are expressed at high levels in the taste system, they likely play little or no role in maintaining adult taste bud structure. IGFs have a potential role in establishing the initial number of taste buds, and there may be limits on epithelial thickness in the absence of IGF1R signaling. PMID:26901525

Genetically Encoded Chemical Probes In Cells Reveal the Binding Path of Urocortin-I to CRF Class B GPCR

PubMed Central

Coin, Irene; Katritch, Vsevolod; Sun, Tingting; Xiang, Zheng; Siu, Fai Yiu; Beyermann, Michael; Stevens, Raymond C.; Wang, Lei

2014-01-01

SUMMARY Molecular determinants regulating the activation of class B G-protein coupled receptors (GPCRs) by native peptide agonists are largely unknown. We have investigated here the interaction between the corticotropin releasing factor receptor type 1 (CRF1R) and its native 40-mer peptide ligand Urocortin-I directly in mammalian cells. By incorporating unnatural amino acid photo-chemical and new click-chemical probes into the receptor, 44 inter-molecular spatial constraints have been derived for the ligand-receptor interaction. The data were analyzed in the context of the recently resolved crystal structure of CRF1R transmembrane domain and existing extracellular domain structures, yielding a complete conformational model for the peptide-receptor complex. Structural features of the receptor-ligand complex yield molecular insights on the mechanism of receptor activation. The experimental strategy provides unique information on full-length post-translationally modified GPCRs in the native membrane of the live cell, complementing in vitro biophysical reductionist approaches. PMID:24290358

Expression of the Human Epidermal Growth Factor Receptor in a Murine T- Cell Hybridoma: A Transmembrane Protein Tyrosine Kinase Can Synergize with the T-Cell Antigen Receptor

DTIC Science & Technology

1992-01-01

protein kirases suchmembrane P17K. nln T ts ebaepoenkr sssc as the EGFR or platelet-derived growth factor re,,,ptor. For instance, the EGFR and TCR...stimulated with EGF (100 ng/mi, in PBS containing phosphatase inhibitors , lysed, and immunoprecip. 5 min, B) anti Thy- I antibody (07 1:50 dilution or...washed in PBS containing phosphatase inhibitors and lysed. Total cellular MX1- lysate was subjected to SDS.PAGE. Western-transferred, and im- Mxi

Azadirachtin interacts with the tumor necrosis factor (TNF) binding domain of its receptors and inhibits TNF-induced biological responses.

PubMed

Thoh, Maikho; Kumar, Pankaj; Nagarajaram, Hampathalu A; Manna, Sunil K

2010-02-19

The role of azadirachtin, an active component of a medicinal plant Neem (Azadirachta indica), on TNF-induced cell signaling in human cell lines was investigated. Azadirachtin blocks TNF-induced activation of nuclear factor kappaB (NF-kappaB) and also expression of NF-kappaB-dependent genes such as adhesion molecules and cyclooxygenase 2. Azadirachtin inhibits the inhibitory subunit of NF-kappaB (IkappaB alpha) phosphorylation and thereby its degradation and RelA (p65) nuclear translocation. It blocks IkappaB alpha kinase (IKK) activity ex vivo, but not in vitro. Surprisingly, azadirachtin blocks NF-kappaB DNA binding activity in transfected cells with TNF receptor-associated factor (TRAF)2, TNF receptor-associated death domain (TRADD), IKK, or p65, but not with TNFR, suggesting its effect is at the TNFR level. Azadirachtin blocks binding of TNF, but not IL-1, IL-4, IL-8, or TNF-related apoptosis-inducing ligand (TRAIL) with its respective receptors. Anti-TNFR antibody or TNF protects azadirachtin-mediated down-regulation of TNFRs. Further, in silico data suggest that azadirachtin strongly binds in the TNF binding site of TNFR. Overall, our data suggest that azadirachtin modulates cell surface TNFRs thereby decreasing TNF-induced biological responses. Thus, azadirachtin exerts an anti-inflammatory response by a novel pathway, which may be beneficial for anti-inflammatory therapy.

Azadirachtin Interacts with the Tumor Necrosis Factor (TNF) Binding Domain of Its Receptors and Inhibits TNF-induced Biological Responses*

PubMed Central

Thoh, Maikho; Kumar, Pankaj; Nagarajaram, Hampathalu A.; Manna, Sunil K.

2010-01-01

The role of azadirachtin, an active component of a medicinal plant Neem (Azadirachta indica), on TNF-induced cell signaling in human cell lines was investigated. Azadirachtin blocks TNF-induced activation of nuclear factor κB (NF-κB) and also expression of NF-κB-dependent genes such as adhesion molecules and cyclooxygenase 2. Azadirachtin inhibits the inhibitory subunit of NF-κB (IκBα) phosphorylation and thereby its degradation and RelA (p65) nuclear translocation. It blocks IκBα kinase (IKK) activity ex vivo, but not in vitro. Surprisingly, azadirachtin blocks NF-κB DNA binding activity in transfected cells with TNF receptor-associated factor (TRAF)2, TNF receptor-associated death domain (TRADD), IKK, or p65, but not with TNFR, suggesting its effect is at the TNFR level. Azadirachtin blocks binding of TNF, but not IL-1, IL-4, IL-8, or TNF-related apoptosis-inducing ligand (TRAIL) with its respective receptors. Anti-TNFR antibody or TNF protects azadirachtin-mediated down-regulation of TNFRs. Further, in silico data suggest that azadirachtin strongly binds in the TNF binding site of TNFR. Overall, our data suggest that azadirachtin modulates cell surface TNFRs thereby decreasing TNF-induced biological responses. Thus, azadirachtin exerts an anti-inflammatory response by a novel pathway, which may be beneficial for anti-inflammatory therapy. PMID:20018848

Insights into the TOR-S6K signaling pathway in maize (Zea mays L.). pathway activation by effector-receptor interaction.

PubMed

Garrocho-Villegas, Verónica; Aguilar C, Raúl; Sánchez de Jiménez, Estela

2013-12-23

The primordial TOR pathway, known to control growth and cell proliferation, has still not been fully described for plants. Nevertheless, in maize, an insulin-like growth factor (ZmIGF) peptide has been reported to stimulate this pathway. This research provides further insight into the TOR pathway in maize, using a biochemical approach in cultures of fast-growing (FG) and slow-growing (SG) calli, as a model system. Our results revealed that addition of either ZmIGF or insulin to SG calli stimulated DNA synthesis and increased the growth rate through cell proliferation and increased the rate of ribosomal protein (RP) synthesis by the selective mobilization of RP mRNAs into polysomes. Furthermore, analysis of the phosphorylation status of the main TOR and S6K kinases from the TOR pathway revealed stimulation by ZmIGF or insulin, whereas rapamycin inhibited its activation. Remarkably, a putative maize insulin-like receptor was recognized by a human insulin receptor antibody, as demonstrated by immunoprecipitation from membrane protein extracts of maize callus. Furthermore, competition experiments between ZmIGF and insulin for the receptor site on maize protoplasts suggested structural recognition of the putative receptor by either effector. These data were confirmed by confocal immunolocalization within the cell membrane of callus cells. Taken together, these data indicate that cell growth and cell proliferation in maize depend on the activation of the TOR-S6K pathway through the interaction of an insulin-like growth factor and its receptor. This evidence suggests that higher plants as well as metazoans have conserved this biochemical pathway to regulate their growth, supporting the conclusion that it is a highly evolved conserved pathway.

The insulin response integrates increased TGF-β signaling through Akt-induced enhancement of cell surface delivery of TGF-β receptors

PubMed Central

Budi, Erine H.; Muthusamy, Baby Periyanayaki; Derynck, Rik

2015-01-01

Increased activity of transforming growth factor β (TGF-β), which binds to and stimulates cell surface receptors, contributes to cancer progression and fibrosis by driving epithelial cells toward a migratory mesenchymal phenotype and increasing the abundance of extracellular matrix proteins. The abundance of TGF-β receptors at the cell surface determines cellular responsiveness to TGF-β, which is often produced by the same cells that have the receptors, and thus serves as an autocrine signal. We found that Akt-mediated phosphorylation of AS160, a RabGAP [guanosine triphosphatase (GTPase)-activating protein] promoted the translocation of TGF-β receptors from intracellular stores to the plasma membrane of mouse embryonic fibroblasts (MEFs) and NMuMG epithelial cells. Consequently, insulin, which is commonly used to treat hyperglycemia and activates Akt signaling, increased the amount of TGF-β receptors at the cell surface, thereby enhancing TGF-β responsiveness. This insulin-induced increase in autocrine TGF-β signaling contributed to insulin-induced gene expression responses, attenuated the epithelial phenotype, and promoted the migration of NMuMG cells. Furthermore, the enhanced delivery of TGF-β receptors at the cell surface enabled insulin to increase TGF-β-induced gene responses. The enhancement of TGF-β responsiveness in response to Akt activation may help to explain the biological effects of insulin, the progression of cancers in which Akt is activated, and the increased incidence of fibroses in diabetes. PMID:26420907

Single-molecule photobleaching reveals increased MET receptor dimerization upon ligand binding in intact cells

PubMed Central

2013-01-01

Background The human receptor tyrosine kinase MET and its ligand hepatocyte growth factor/scatter factor are essential during embryonic development and play an important role during cancer metastasis and tissue regeneration. In addition, it was found that MET is also relevant for infectious diseases and is the target of different bacteria, amongst them Listeria monocytogenes that induces bacterial uptake through the surface protein internalin B. Binding of ligand to the MET receptor is proposed to lead to receptor dimerization. However, it is also discussed whether preformed MET dimers exist on the cell membrane. Results To address these issues we used single-molecule fluorescence microscopy techniques. Our photobleaching experiments show that MET exists in dimers on the membrane of cells in the absence of ligand and that the proportion of MET dimers increases significantly upon ligand binding. Conclusions Our results indicate that partially preformed MET dimers may play a role in ligand binding or MET signaling. The addition of the bacterial ligand internalin B leads to an increase of MET dimers which is in agreement with the model of ligand-induced dimerization of receptor tyrosine kinases. PMID:23731667

Emodin Suppresses Maintenance of Stemness by Augmenting Proteosomal Degradation of Epidermal Growth Factor Receptor/Epidermal Growth Factor Receptor Variant III in Glioma Stem Cells

PubMed Central

Kim, Jeongyub; Lee, Jong-Seon; Jung, Jieun; Lim, Inhye; Lee, Ji-Yun

2015-01-01

There is a growing body of evidence that small subpopulations of cells with stem cell-like characteristics within most solid tumors are responsible for the malignancy of aggressive cancer cells and that targeting these cells might be a good therapeutic strategy to reduce the risk of tumor relapse after therapy. Here, we examined the effects of emodin (1,3,8-trihydroxy-6-methylanthraquinone), an active component of the root and rhizome of Rheum palmatum that has several biological activities, including antitumor effects, on primary cultured glioma stem cells (GSCs). Emodin inhibited the self-renewal activity of GSCs in vitro as evidenced by neurosphere formation, limiting dilution, and soft agar clonogenic assays. Emodin inhibited the maintenance of stemness by suppressing the expression of Notch intracellular domain, nonphosphorylated β-catenin, and phosphorylated STAT3 proteins. In addition, treatment with emodin partially induced apoptosis, reduced cell invasiveness, and sensitized GSCs to ionizing radiation. Intriguingly, emodin induced proteosomal degradation of epidermal growth factor receptor (EGFR)/EGFR variant III (EGFRvIII) by interfering with the association of EGFR/EGFRvIII with heat shock protein 90, resulting in the suppression of stemness pathways. Based on these data, we propose that emodin could be considered as a potent therapeutic adjuvant that targets GSCs. PMID:25229646

Paracrine-Mediated Neuroprotection and Neuritogenesis of Axotomised Retinal Ganglion Cells by Human Dental Pulp Stem Cells: Comparison with Human Bone Marrow and Adipose-Derived Mesenchymal Stem Cells

PubMed Central

Mead, Ben; Logan, Ann; Berry, Martin

2014-01-01

We have investigated and compared the neurotrophic activity of human dental pulp stem cells (hDPSC), human bone marrow-derived mesenchymal stem cells (hBMSC) and human adipose-derived stem cells (hAMSC) on axotomised adult rat retinal ganglion cells (RGC) in vitro in order to evaluate their therapeutic potential for neurodegenerative conditions of RGC. Using the transwell system, RGC survival and length/number of neurites were quantified in coculture with stem cells in the presence or absence of specific Fc-receptor inhibitors to determine the role of NGF, BDNF, NT-3, VEGF, GDNF, PDGF-AA and PDGF-AB/BB in stem cell-mediated RGC neuroprotection and neuritogenesis. Conditioned media, collected from cultured hDPSC/hBMSC/hAMSC, were assayed for the secreted growth factors detailed above using ELISA. PCR array determined the hDPSC, hBMSC and hAMSC expression of genes encoding 84 growth factors and receptors. The results demonstrated that hDPSC promoted significantly more neuroprotection and neuritogenesis of axotomised RGC than either hBMSC or hAMSC, an effect that was neutralized after the addition of specific Fc-receptor inhibitors. hDPSC secreted greater levels of various growth factors including NGF, BDNF and VEGF compared with hBMSC/hAMSC. The PCR array confirmed these findings and identified VGF as a novel potentially therapeutic hDPSC-derived neurotrophic factor (NTF) with significant RGC neuroprotective properties after coculture with axotomised RGC. In conclusion, hDPSC promoted significant multi-factorial paracrine-mediated RGC survival and neurite outgrowth and may be considered a potent and advantageous cell therapy for retinal nerve repair. PMID:25290916

Melanocyte development: with a message of encouragement to young women scientists.

PubMed

Mizoguchi, Masako

2004-10-01

This is a semi-biographical review describing my research on melanocyte development and related personal experiences. Having been educated and trained as a dermatologist, I have been involved in many clinically-oriented studies, however, what has always interested me the most is pigment cell biology. Since I started working at St Marianna University in 1991, I have been undertaking research on melanocyte development and relevant growth factors using mice as models. My research in this field was inspired by my collaborations with various scientists, mostly from the field of biology. Many of these specialists I have met at meetings of the Societies of Pigment Cell Research (PCR). Stem cell factor (SCF, Kitl) and endothelin 3 (EDN3) have been identified as indispensable factors regulating the development of melanocytes. Mice mutant at loci encoding those factors (or their receptors) such as Sl/Sl (receptors W/W) and ls/ls (receptors s/s) have white coat colors and white patches, respectively. Our murine neural crest cell (NCC) primary cultures derived from Sl/Sl embryos showed that EDN3 cannot develop melanocyte precursors without SCF and that EDN3 can elicit proliferation and differentiation in the presence of SCF. These results suggest that without EDN3 and the endothelin type B receptor (EDNRB), melanocytes can not fully increase in number, which could well be the cause of the partial white coat color of ls/ls and s/s mice. Contamination with factors derived from the serum in medium or in feeder cells sometimes causes experimental errors, and therefore we established three immortal cell lines derived from NCC in different developmental stages and designated them as NCCmelb4, NCCmelb4M5 and NCCmelan5, all of which can survive without feeder cells. Using these cell lines and NCC primary cultures, we studied the effect of many factors related to melanocyte development. From the results, it has become evident that Vitamin D3 induces EDNRB expression by NCCmelb4 cells. In addition to the International Pigment Cell Conference (IPCC), I have also taken part in many annual meetings of the Japanese Society for Pigment Cell Research (JSPCR), Pan American Society for Pigment Cell Research (PASPCR) and European Society for Pigment Cell Research (ESPCR). Not only have I learned a great deal, I have enjoyed myself immensely at those meetings. Moreover, I have made many good friends there, some of whom I have collaborated with in my research. To conclude, I would like to give my message 'be ambitious' to young scientists, especially young women.

17beta-estradiol promotes breast cancer cell proliferation-inducing stromal cell-derived factor-1-mediated epidermal growth factor receptor transactivation: reversal by gefitinib pretreatment.

PubMed

Pattarozzi, Alessandra; Gatti, Monica; Barbieri, Federica; Würth, Roberto; Porcile, Carola; Lunardi, Gianluigi; Ratto, Alessandra; Favoni, Roberto; Bajetto, Adriana; Ferrari, Angelo; Florio, Tullio

2008-01-01

The coordinated activity of estrogens and epidermal growth factor receptor (EGFR) family agonists represents the main determinant of breast cancer cell proliferation. Stromal cell-derived factor-1 (SDF-1) enhances extracellular signal-regulated kinases 1 and 2 (ERK1/2) activity via the transactivation of EGFR and 17beta-estradiol (E2) induces SDF-1 production to exert autocrine proliferative effects. On this basis, we evaluated whether the inhibition of the tyrosine kinase (TK) activity of EGFR may control different mitogenic stimuli in breast tumors using the EGFR-TK inhibitor gefitinib to antagonize the proliferation induced by E2 in T47D human breast cancer cells. EGF, E2, and SDF-1 induced a dose-dependent T47D cell proliferation, that being nonadditive suggested the activation of common intracellular pathways. Gefitinib treatment inhibited not only the EGF-dependent proliferation and ERK1/2 activation but also the effects of SDF-1 and E2, suggesting that these activities were mediated by EGFR transactivation. Indeed, both SDF-1 and E2 caused EGFR tyrosine phosphorylation. The molecular link between E2 and SDF-1 proliferative effects was identified because 1,1'-(1,4-phenylenebis(methylene))-bis-1,4,8,11-tetraazacyclotetradecane octahydrochloride (AMD3100), a CXCR4 antagonist, inhibited SDF-1- and E2-dependent proliferation and EGFR and ERK1/2 phosphorylation. EGFR transactivation was dependent on c-Src activation. E2 treatment caused a powerful SDF-1 release from T47D cells. Finally, in SKBR3, E2-resistant cells, EGFR was constitutively activated, and AMD3100 reduced EGFR phosphorylation and cell proliferation, whereas HER2-neu was transactivated by SDF-1 in SKBR3 but not in T47D cells. In conclusion, we show that activation of CXCR4 transduces proliferative signals from the E2 receptor to EGFR, whose inhibition is able to revert breast cancer cell proliferation induced by multiple receptor activation.

Regulation of EGF receptor signaling by the MARVEL domain-containing protein CKLFSF8.

PubMed

Jin, Caining; Ding, Peiguo; Wang, Ying; Ma, Dalong

2005-11-21

It is known that chemokine-like factor superfamily 8 (CKLFSF8), a member of the CKLF superfamily, has four putative transmembrane regions and a MARVEL domain. Its structure is similar to TM4SF11 (plasmolipin) and widely distributed in normal tissue. However, its function is not yet known. We show here that CKLFSF8 is associated with the epidermal growth factor receptor (EGFR) and that ectopic expression of CKLFSF8 in several cell lines suppresses EGF-induced cell proliferation, whereas knockdown of CKLFSF8 by siRNA promotes cell proliferation. In cells overexpressing CKLFSF8, the initial activation of EGFR was not affected, but subsequent desensitization of EGF-induced signaling occurred rapidly. This attenuation was correlated with an increased rate of receptor endocytosis. In contrast, knockdown of CKLFSF8 by siCKLFSF8 delayed EGFR endocytosis. These results identify CKLFSF8 as a novel regulator of EGF-induced signaling and indicate that the association of EGFR with four transmembrane proteins is critical for EGFR desensitization.

p75 neurotrophin receptor and pro-BDNF promote cell survival and migration in clear cell renal cell carcinoma

PubMed Central

Sánchez-Prieto, Ricardo; Saada, Sofiane; Naves, Thomas; Guillaudeau, Angélique; Perraud, Aurélie; Sindou, Philippe; Lacroix, Aurélie; Descazeaud, Aurélien; Lalloué, Fabrice; Jauberteau, Marie-Odile

2016-01-01

p75NTR, a member of TNF receptor family, is the low affinity receptor common to several mature neurotrophins and the high affinity receptor for pro-neurotrophins. Brain-Derived Neurotrophic Factor (BDNF), a member of neurotrophin family has been described to play an important role in development and progression of several cancers, through its binding to a high affinity tyrosine kinase receptor B (TrkB) and/or p75NTR. However, the functions of these two receptors in renal cell carcinoma (RCC) have never been investigated. An overexpression of p75NTR, pro-BDNF, and to a lesser extent for TrkB and sortilin, was detected by immunohistochemistry in a cohort of 83 clear cell RCC tumors. p75NTR, mainly expressed in tumor tissues, was significantly associated with higher Fuhrman grade in multivariate analysis. In two derived-RCC lines, 786-O and ACHN cells, we demonstrated that pro-BDNF induced cell survival and migration, through p75NTR as provided by p75NTR RNA silencing or blocking anti-p75NTR antibody. This mechanism is independent of TrkB activation as demonstrated by k252a, a tyrosine kinase inhibitor for Trk neurotrophin receptors. Taken together, these data highlight for the first time an important role for p75NTR in renal cancer and indicate a putative novel target therapy in RCC. PMID:27120782

Trefoil factor 3 (TFF3) from human breast milk activates PAR-2 receptors, of the intestinal epithelial cells HT-29, regulating cytokines and defensins.

PubMed

Barrera, G J; Tortolero, G Sanchez

2016-01-01

Trefoil factors are effector molecules in gastrointestinal tract physiology. Each one improves healing of the gastrointestinal tract. Trefoil factors may be grouped into three classes: the gastric peptides (TFF1), spasmolytic peptide (TFF2) and intestinal trefoil factor (TFF3). Significant amounts of TFF3 are present in human breast milk. Previously, we have reported that trefoil factor 3 isolated from human breast milk produces down regulation of cytokines and promotes human beta defensins expression in intestinal epithelial cells. This study aimed to determine the molecular mechanism involved. Here we showed that the presence of TFF3 strongly correlated with protease activated receptors 2 (PAR-2) activation in human intestinal cells. Intracellular calcium ((Ca2+)i)mobilization was induced by the treatment with: 1) TFF3, 2) synthetic PAR-2 agonist peptide. The co-treatment with a synthetic PAR-2 antagonist peptide and TFF3 eliminates the latter's effect. Additionally, we demonstrated the existence of interactions among TFF3 and PAR-2 receptors through far Western blot and co-precipitation. Finally, down regulation of PAR-2 by siRNA resulted in a decrease of TFF3 induced intracellular (Ca2+)i mobilization, cytokine regulation and defensins expression. These findings suggest that TFF3 activates intestinal cells through PAR-2 (Fig. 4, Ref. 19).

Non-conventional Frizzled ligands and Wnt receptors.

PubMed

Hendrickx, Marijke; Leyns, Luc

2008-05-01

The Wnt family of secreted signaling factors plays numerous roles in embryonic development and in stem cell biology. In the adult, Wnt signaling is involved in tissue homeostasis and mutations that lead to the overexpression of Wnt can be linked to cancer. Wnt signaling is transduced intracellularly by the Frizzled (Fzd) family of receptors. In the canonical pathway, accumulation of beta-catenin and the subsequent formation of a complex with T cell factors (TCF) or lymphoid enhancing factors (Lef) lead to target gene activation. The identification of Ryk as an alternative Wnt receptor and the discovery of the novel Fzd ligands Norrie disease protein (NDP) and R-Spondin, changed the traditional view of Wnts binding to Fzd receptors. Mouse R-Spondin cooperates with Wnt signaling and Low density lipoprotein (LDL) receptor related protein (LRP) to activate beta-catenin dependent gene expression and is involved in processes such as limb and placental development in the mouse. NDP is the product of the Norrie disease gene and controls vascular development in the retina, inner ear and in the female reproductive system during pregnancy. In this review a functional overview of the interactions of the different Wnt and non-Wnt ligands with the Fzd receptors is given as well as a survey of Wnts binding to Ryk and we discuss the biological significance of these interactions.

Fibroblast growth factor receptors, developmental corruption and malignant disease.

PubMed

Kelleher, Fergal C; O'Sullivan, Hazel; Smyth, Elizabeth; McDermott, Ray; Viterbo, Antonella

2013-10-01

Fibroblast growth factors (FGF) are a family of ligands that bind to four different types of cell surface receptor entitled, FGFR1, FGFR2, FGFR3 and FGFR4. These receptors differ in their ligand binding affinity and tissue distribution. The prototypical receptor structure is that of an extracellular region comprising three immunoglobulin (Ig)-like domains, a hydrophobic transmembrane segment and a split intracellular tyrosine kinase domain. Alternative gene splicing affecting the extracellular third Ig loop also creates different receptor isoforms entitled FGFRIIIb and FGFRIIIc. Somatic fibroblast growth factor receptor (FGFR) mutations are implicated in different types of cancer and germline FGFR mutations occur in developmental syndromes particularly those in which craniosynostosis is a feature. The mutations found in both conditions are often identical. Many somatic FGFR mutations in cancer are gain-of-function mutations of established preclinical oncogenic potential. Gene amplification can also occur with 19-22% of squamous cell lung cancers for example having amplification of FGFR1. Ontologic comparators can be informative such as aberrant spermatogenesis being implicated in both spermatocytic seminomas and Apert syndrome. The former arises from somatic FGFR3 mutations and Apert syndrome arises from germline FGFR2 mutations. Finally, therapeutics directed at inhibiting the FGF/FGFR interaction are a promising subject for clinical trials.

N-methyl-N'-nitro-N-nitrosoguanidine interferes with the epidermal growth factor receptor-mediated signaling pathway.

PubMed

Gao, Zhihua; Yang, Jun; Huang, Yun; Yu, Yingnian

2005-03-01

Many environmental factors, such as ultraviolet (UV) and arsenic, can induce the clustering of cell surface receptors, including epidermal growth factor receptor (EGFR). This is accompanied by the phosphorylation of the receptors and the activation of ensuing cellular signal transduction pathways, which are implicated in the various cellular responses caused by the exposure to these factors. In this study, we have shown that N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), an alkylating agent, also induced the clustering of EGFR in human amnion FL cells, which was similar in morphology to that of epidermal growth factor treatment. However, MNNG treatment did not activate Ras, the downstream mediator in EGFR signaling pathway, as compared to EGF treatment. The autophosphorylation of tyrosine residues Y1068 and Y1173 at the intracellular domain of EGFR, which is related to Ras activation under EGF treatment, was also not observed by MNNG exposure. Interestingly, although MNNG did not affect the binding of EGF to EGFR, MNNG can interfere with EGF function. For instance, pre-incubating FL cells with MNNG inhibited the autophosphorylation of EGFR by EGF treatment, as well as the activation of Ras. In addition, the phosphorylation of Y845 on EGFR by EGF, which is mediated through c-Src or related kinases but not autophosphorylation, was also affected by MNNG. Therefore, MNNG may influence the tyrosine kinase activity as well as the phosphorylation of EGFR through its interaction with EGFR.

CSF1R mutations in hereditary diffuse leukoencephalopathy with spheroids are loss of function

NASA Astrophysics Data System (ADS)

Pridans, Clare; Sauter, Kristin A.; Baer, Kristin; Kissel, Holger; Hume, David A.

2013-10-01

Hereditary diffuse leukoencephalopathy with spheroids (HDLS) in humans is a rare autosomal dominant disease characterized by giant neuroaxonal swellings (spheroids) within the CNS white matter. Symptoms are variable and can include personality and behavioural changes. Patients with this disease have mutations in the protein kinase domain of the colony-stimulating factor 1 receptor (CSF1R) which is a tyrosine kinase receptor essential for microglia development. We investigated the effects of these mutations on Csf1r signalling using a factor dependent cell line. Corresponding mutant forms of murine Csf1r were expressed on the cell surface at normal levels, and bound CSF1, but were not able to sustain cell proliferation. Since Csf1r signaling requires receptor dimerization initiated by CSF1 binding, the data suggest a mechanism for phenotypic dominance of the mutant allele in HDLS.

Potential upstream regulators of cannabinoid receptor 1 signaling in prostate cancer: a Bayesian network analysis of data from a tissue microarray.

PubMed

Häggström, Jenny; Cipriano, Mariateresa; Forshell, Linus Plym; Persson, Emma; Hammarsten, Peter; Stella, Nephi; Fowler, Christopher J

2014-08-01

The endocannabinoid system regulates cancer cell proliferation, and in prostate cancer a high cannabinoid CB1 receptor expression is associated with a poor prognosis. Down-stream mediators of CB1 receptor signaling in prostate cancer are known, but information on potential upstream regulators is lacking. Data from a well-characterized tumor tissue microarray were used for a Bayesian network analysis using the max-min hill-climbing method. In non-malignant tissue samples, a directionality of pEGFR (the phosphorylated form of the epidermal growth factor receptor) → CB1 receptors were found regardless as to whether the endocannabinoid metabolizing enzyme fatty acid amide hydrolase (FAAH) was included as a parameter. A similar result was found in the tumor tissue, but only when FAAH was included in the analysis. A second regulatory pathway, from the growth factor receptor ErbB2 → FAAH was also identified in the tumor samples. Transfection of AT1 prostate cancer cells with CB1 receptors induced a sensitivity to the growth-inhibiting effects of the CB receptor agonist CP55,940. The sensitivity was not dependent upon the level of receptor expression. Thus a high CB1 receptor expression alone does not drive the cells towards a survival phenotype in the presence of a CB receptor agonist. The data identify two potential regulators of the endocannabinoid system in prostate cancer and allow the construction of a model of a dysregulated endocannabinoid signaling network in this tumor. Further studies should be designed to test the veracity of the predictions of the network analysis in prostate cancer and other solid tumors. © 2014 The Authors. The Prostate published by Wiley Periodicals, Inc.

Gab-family adapter molecules in signal transduction of cytokine and growth factor receptors, and T and B cell antigen receptors.

PubMed

Hibi, M; Hirano, T

2000-04-01

Gab1 and Gab2 (Grb2 associated binder 1 and 2) are scaffolding adapter molecules that display sequence similarity with Drosophila DOS (daughter of sevenless), which is a potential substrate for the protein tyrosine phosphatase, Corkscrew, Both Gab1 and Gab2, like DOS, have a pleckstrin homology domain and potential binding sites for SH2 and SH3 domains. Gab1 and Gab2 are phosphorylated on tyrosine upon the stimulation of various cytokines, growth factors, and antigen receptors, and interact with signaling molecules, such as Grb2, SHP-2, and PI-3 kinase. Overexpression of Gab1 or Gab2 mimics or enhances growth factor or cytokine-mediated biological processes and activates ERK MAP kinase. These data imply that Gab1 and Gab2 act downstream of a broad range of cytokine and growth factor receptors, as well as T and B antigen receptors, and link these receptors to ERK MAP kinase and biological actions.

A lactobacillus rhamnosus GG-derived soluble protein, p40, stimulates ligand release from intestinal epithelial cells to transactivate epidermal growth factor receptor

USDA-ARS?s Scientific Manuscript database

Protein p40, a Lactobacillus rhamnosus GG (LGG)-derived soluble protein, ameliorates intestinal injury and colitis, reduces apoptosis and preserves barrier function by activation of EGF receptor (EGFR) in intestinal epithelial cells. The aim of this study was to determine the mechanisms by which p40...

L1CAM stimulates glioma cell motility and proliferation through the fibroblast growth factor receptor.

PubMed

Mohanan, Vishnu; Temburni, Murali K; Kappes, John C; Galileo, Deni S

2013-04-01

The L1CAM cell adhesion/recognition molecule (L1, CD171) and fibroblast growth factor receptor (FGFR) both are expressed by human high-grade glioma cells, but their potential actions in controlling cell behavior have not been linked. L1 actions in cancer cells have been attributed mainly to integrin receptors, and we demonstrated previously that L1-stimulated glioma cell migration correlates with integrin expression, increased focal adhesion kinase activation and focal complex turnover. Our analyses of datasets revealed FGFR is overexpressed in glioma regardless of grade, while ADAM10 metalloprotease expression increases with glioma grade. Here, we used dominant-negative and short hairpin RNA approaches to inhibit the activation of FGFR1 and expression of L1, respectively. An L1 peptide that inhibits L1-FGFR interaction and PD173074, a chemical inhibitor of FGFR1 activity, also were used to elucidate the involvement of L1-FGFR interactions on glioma cell behavior. Time-lapse cell motility studies and flow cytometry cell cycle analyses showed that L1 operates to increase glioma cell motility and proliferation through FGFR activation. Shutdown of both L1 expression and FGFR activity in glioma cells resulted in a complete termination of cell migration in vitro. These studies show for the first time that soluble L1 ectodomain (L1LE) acts on glioma cells through FGFRs, and that FGFRs are used by glioma cells for increasing motility as well as proliferation in response to activation by L1LE ligand. Thus, effective treatment of high-grade glioma may require simultaneous targeting of L1, FGFRs, and integrin receptors, which would reduce glioma cell motility as well as proliferation.

Transcriptional response to muscarinic acetylcholine receptor stimulation: regulation of Egr-1 biosynthesis by ERK, Elk-1, MKP-1, and calcineurin in carbachol-stimulated human neuroblastoma cells.

PubMed

Rössler, Oliver G; Henss, Isabell; Thiel, Gerald

2008-02-01

Carbachol-mediated activation of type M(3) muscarinic acetylcholine receptors induces the biosynthesis of the transcription factor Egr-1 in human SH-SY5Y neuroblastoma cells involving an activation of extracellular signal-regulated protein kinase. Carbachol triggered the phosphorylation of the ternary complex factor Elk-1, a key transcriptional regulator of serum response element-driven gene transcription, and strikingly enhanced the transcriptional activation potential of Elk-1. Chromatin immunoprecipitation experiments revealed that Elk-1 binds in vivo to the 5'-upstream region of the Egr-1 gene in carbachol-stimulated neuroblastoma cells. Together, these data indicate that Elk-1 connects the intracellular signaling cascade elicited by activation of M(3) muscarinic acetylcholine receptors with the transcription of the Egr-1 gene. Lentiviral-mediated expression of either MAP kinase phosphatase-1 (MKP-1) or a constitutively active mutant of calcineurin A inhibited Egr-1 biosynthesis following carbachol stimulation, indicating that these phosphatases function as shut-off devices of muscarinic acetylcholine receptor signaling. Additionally, carbachol stimulation increased transcription of a chromatin-embedded collagenase promoter/reporter gene, showing that AP-1 activity is enhanced in carbachol-stimulated neuroblastoma. Expression experiments revealed that both MKP-1 and a constitutively active mutant of calcineurin A impaired carbachol-induced upregulation of AP-1 activity. The fact that carbachol stimulation of neuroblastoma cells activates the transcription factors Egr-1 and AP-1 suggests that changes in the gene expression pattern are an integral part of muscarinic acetylcholine receptor signaling.

Thymic self-reactivity selects natural interleukin 17-producing T cells that can regulate peripheral inflammation

PubMed Central

Marks, Benjamin R.; Nowyhed, Heba N.; Choi, Jin-Young; Poholek, Amanda C.; Odegard, Jared M.; Flavell, Richard A.; Craft, Joe

2009-01-01

Interleukin 17 (IL-17)-producing CD4+ T (TH-17) cells share a developmental relationship with FoxP3+ regulatory T (Treg) cells. Here we show that a TH-17 population differentiates within the thymus in a manner influenced by self-antigen recognition, and by the cytokines IL-6 and transforming growth factor (TGF)-β. Like previously described TH-17 cells, TH-17 cells that develop in the thymus expressed the orphan nuclear receptor RORγt and the IL-23 receptor. These cells also expressed α4β1 integrins and the chemokine receptor CCR6, and were recruited to the lung, gut, and liver. In the liver these cells secreted IL-22 in response to self-antigen and mediated host protection during inflammation. Thus, TH-17 cells, like Treg cells, can be selected by self-antigens in the thymus. PMID:19734905

Rac-mediated Stimulation of Phospholipase Cγ2 Amplifies B Cell Receptor-induced Calcium Signaling*♦

PubMed Central

Walliser, Claudia; Tron, Kyrylo; Clauss, Karen; Gutman, Orit; Kobitski, Andrei Yu.; Retlich, Michael; Schade, Anja; Röcker, Carlheinz; Henis, Yoav I.; Nienhaus, G. Ulrich; Gierschik, Peter

2015-01-01

The Rho GTPase Rac is crucially involved in controlling multiple B cell functions, including those regulated by the B cell receptor (BCR) through increased cytosolic Ca2+. The underlying molecular mechanisms and their relevance to the functions of intact B cells have thus far remained unknown. We have previously shown that the activity of phospholipase Cγ2 (PLCγ2), a key constituent of the BCR signalosome, is stimulated by activated Rac through direct protein-protein interaction. Here, we use a Rac-resistant mutant of PLCγ2 to functionally reconstitute cultured PLCγ2-deficient DT40 B cells and to examine the effects of the Rac-PLCγ2 interaction on BCR-mediated changes of intracellular Ca2+ and regulation of Ca2+-regulated and nuclear-factor-of-activated-T-cell-regulated gene transcription at the level of single, intact B cells. The results show that the functional Rac-PLCγ2 interaction causes marked increases in the following: (i) sensitivity of B cells to BCR ligation; (ii) BCR-mediated Ca2+ release from intracellular stores; (iii) Ca2+ entry from the extracellular compartment; and (iv) nuclear translocation of the Ca2+-regulated nuclear factor of activated T cells. Hence, Rac-mediated stimulation of PLCγ2 activity serves to amplify B cell receptor-induced Ca2+ signaling. PMID:25903139

An interaction between hepatocyte growth factor and its receptor (c-MET) prolongs the survival of chronic lymphocytic leukemic cells through STAT3 phosphorylation: a potential role of mesenchymal cells in the disease.

PubMed

Giannoni, Paolo; Scaglione, Silvia; Quarto, Rodolfo; Narcisi, Roberto; Parodi, Manuela; Balleari, Enrico; Barbieri, Federica; Pattarozzi, Alessandra; Florio, Tullio; Ferrini, Silvano; Corte, Giorgio; de Totero, Daniela

2011-07-01

Chronic lymphocytic leukemia cells are characterized by an apparent longevity in vivo which is lost when they are cultured in vitro. Cellular interactions and factors provided by the microenvironment appear essential to cell survival and may protect leukemic cells from the cytotoxicity of conventional therapies. Understanding the cross-talk between leukemic cells and stroma is of interest for identifying signals supporting disease progression and for developing novel therapeutic strategies. Different cell types, sharing a common mesenchymal origin and representative of various bone marrow components, were used to challenge the viability of leukemic cells in co-cultures and in contact-free culture systems. Using a bioinformatic approach we searched for genes shared by lineages prolonging leukemic cell survival and further analyzed their biological role in signal transduction experiments. Human bone marrow stromal cells, fibroblasts, trabecular bone-derived cells and an osteoblast-like cell line strongly enhanced survival of leukemic cells, while endothelial cells and chondrocytes did not. Gene expression profile analysis indicated two soluble factors, hepatocyte growth factor and CXCL12, as potentially involved. We demonstrated that hepatocyte growth factor and CXCL12 are produced only by mesenchymal lineages that sustain the survival of leukemic cells. Indeed chronic lymphocytic leukemic cells express a functional hepatocyte growth factor receptor (c-MET) and hepatocyte growth factor enhanced the viability of these cells through STAT3 phosphorylation, which was blocked by a c-MET tyrosine kinase inhibitor. The role of hepatocyte growth factor was confirmed by its short interfering RNA-mediated knock-down in mesenchymal cells. The finding that hepatocyte growth factor prolongs the survival of chronic lymphocytic leukemic cells is novel and we suggest that the interaction between hepatocyte growth factor-producing mesenchymal and neoplastic cells contributes to maintenance of the leukemic clone.

An interaction between hepatocyte growth factor and its receptor (c-MET) prolongs the survival of chronic lymphocytic leukemic cells through STAT3 phosphorylation: a potential role of mesenchymal cells in the disease

PubMed Central

Giannoni, Paolo; Scaglione, Silvia; Quarto, Rodolfo; Narcisi, Roberto; Parodi, Manuela; Balleari, Enrico; Barbieri, Federica; Pattarozzi, Alessandra; Florio, Tullio; Ferrini, Silvano; Corte, Giorgio; de Totero, Daniela

2011-01-01

Background Chronic lymphocytic leukemia cells are characterized by an apparent longevity in vivo which is lost when they are cultured in vitro. Cellular interactions and factors provided by the microenvironment appear essential to cell survival and may protect leukemic cells from the cytotoxicity of conventional therapies. Understanding the cross-talk between leukemic cells and stroma is of interest for identifying signals supporting disease progression and for developing novel therapeutic strategies. Design and Methods Different cell types, sharing a common mesenchymal origin and representative of various bone marrow components, were used to challenge the viability of leukemic cells in co-cultures and in contact-free culture systems. Using a bioinformatic approach we searched for genes shared by lineages prolonging leukemic cell survival and further analyzed their biological role in signal transduction experiments. Results Human bone marrow stromal cells, fibroblasts, trabecular bone-derived cells and an osteoblast-like cell line strongly enhanced survival of leukemic cells, while endothelial cells and chondrocytes did not. Gene expression profile analysis indicated two soluble factors, hepatocyte growth factor and CXCL12, as potentially involved. We demonstrated that hepatocyte growth factor and CXCL12 are produced only by mesenchymal lineages that sustain the survival of leukemic cells. Indeed chronic lymphocytic leukemic cells express a functional hepatocyte growth factor receptor (c-MET) and hepatocyte growth factor enhanced the viability of these cells through STAT3 phosphorylation, which was blocked by a c-MET tyrosine kinase inhibitor. The role of hepatocyte growth factor was confirmed by its short interfering RNA-mediated knock-down in mesenchymal cells. Conclusions The finding that hepatocyte growth factor prolongs the survival of chronic lymphocytic leukemic cells is novel and we suggest that the interaction between hepatocyte growth factor-producing mesenchymal and neoplastic cells contributes to maintenance of the leukemic clone. PMID:21486864

High molecular weight FGF2: the biology of a nuclear growth factor

PubMed Central

Chlebova, K.; Bryja, V.; Dvorak, P.; Kozubik, A.; Wilcox, W. R.

2011-01-01

Fibroblast growth factor 2 (FGF2) is one of the most studied growth factors to date. Most attention has been dedicated to the smallest, 18kDa FGF2 variant that is released by cells and acts through activation of cell-surface FGF-receptor tyrosine kinases. There are, however, several higher molecular weight (HMW) variants of FGF2 that rarely leave their producing cells, are retained in the nucleus and act independently of FGF-receptors (FGFR). Despite significant evidence documenting the expression and intracellular trafficking of HMW FGF2, many important questions remain about the physiological roles and mechanisms of action of HMW FGF2. In this review, we summarize the current knowledge about the biology of HMW FGF2, its role in disease and areas for future investigation. PMID:18850066

K-sam, an amplified gene in stomach cancer, is a member of the heparin-binding growth factor receptor genes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hattori, Yutaka; Odagiri, Hiroki; Nakatani, Hiroshi

1990-08-01

DNA fragments amplified in a stomach cancer-derived cell line, KATO-III, were previously identified by the in-gel DNA renaturation method, and a 0.2-kilobase-pair fragment of the amplified sequence was subsequently cloned. By genomic walking, a portion of the exon of the gene flanking this 0.2-kilobase-pair fragment was cloned, and the gene was designated as K-sam ({und K}ATO-III cell-derived {und s}tomach cancer {und am}plified gene). The K-sam cDNAs, corresponding to the 3.5-kilobase K-sam mRNA, were cloned from the KATO-III cells. Sequence analysis revealed that this gene coded for 682 amino acid residues that satisfied the characteristics of the receptor tyrosine kinase. Themore » K-sam gene had significant homologies with bek, FLG, and chicken basic fibroblast growth factor receptor gene. The K-sam gene was amplified in KATO-III cells with the major transcript of 3.5-kilobases in size. This gene was also expressed in some other stomach cancer cells, a small cell lung cancer, and germ cell tumors.« less

The Role of Mammalian Target of Rapamycin (mTOR) in Insulin Signaling.

PubMed

Yoon, Mee-Sup

2017-10-27

The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that controls a wide spectrum of cellular processes, including cell growth, differentiation, and metabolism. mTOR forms two distinct multiprotein complexes known as mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2), which are characterized by the presence of raptor and rictor, respectively. mTOR controls insulin signaling by regulating several downstream components such as growth factor receptor-bound protein 10 (Grb10), insulin receptor substrate (IRS-1), F-box/WD repeat-containing protein 8 (Fbw8), and insulin like growth factor 1 receptor/insulin receptor (IGF-IR/IR). In addition, mTORC1 and mTORC2 regulate each other through a feedback loop to control cell growth. This review outlines the current understanding of mTOR regulation in insulin signaling in the context of whole body metabolism.

Tyrosine kinase inhibitor induced growth factor receptor upregulation enhances the efficacy of near-infrared targeted photodynamic therapy in esophageal adenocarcinoma cell lines.

PubMed

Hartmans, Elmire; Linssen, Matthijs D; Sikkens, Claire; Levens, Afra; Witjes, Max J H; van Dam, Gooitzen M; Nagengast, Wouter B

2017-05-02

Esophageal carcinoma (EC) is a global health problem, with disappointing 5-year survival rates of only 15-25%. Near-infrared targeted photodynamic therapy (NIR-tPDT) is a novel strategy in which cancer-targeted phototoxicity is able to selectively treat malignant cells. In this in vitro report we demonstrate the applicability of antibody-based NIR-tPDT in esophageal adenocarcinoma (EAC), using the phototoxic compounds cetuximab-IRDye700DX and trastuzumab-IRDye700DX, targeting respectively epidermal growth factor receptor 1 (EGFR) and 2 (HER2). Furthermore, we demonstrate that NIR-tPDT can be made more effective by tyrosine kinase inhibitor (TKI) induced growth receptor upregulation. Together, these results unveil a novel strategy for non-invasive EAC treatment, and by pretreatment-induced receptor upregulation its future clinical application may be optimized.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amagai, Yosuke; Tanaka, Akane; Ohmori, Keitaro

Much is known regarding participations of mast cells with innate and acquired immunity by secreting various cytokines and chemical mediators. However, details of mast cell biology still remain unclear. In this study, we successfully established a novel growth factor-independent mast cell line (MPT-1) derived from canine mast cell tumor. MPT-1 cells manifested factor-independent proliferation as floating cells containing a large amount of histamine, as well as chymase-like dog mast cell protease 3, in cytosolic granules. Particularly, MPT-1 cells expressed high-affinity IgE receptors (Fc{epsilon}RI) and wild-type c-kit receptors. Degranulation of MPT-1 cells was induced not only by stimulation with calcium ionophoremore » but also by cross-linkage of the surface IgE. Given that MPT-1 is the first mast cell line with Fc{epsilon}RI which has no c-kit mutations, MPT-1 cells may provide great contribution for investigation of IgE-mediated activation mechanisms of mast cells, leading to development of effective treatment for allergic disorders.« less

Neurotrophins, their receptors and KI-67 in human GH-secreting pituitary adenomas: an immunohistochemical analysis.

PubMed

Artico, M; Bianchi, E; Magliulo, G; De Vincentiis, M; De Santis, E; Orlandi, A; Santoro, A; Pastore, F S; Giangaspero, F; Caruso, R; Re, M; Fumagalli, L

2012-01-01

Pituitary adenomas are a diverse group of tumors arising from the pituitary gland. Typically, they are small, slow-growing, hormonally inactive lesions that come to light as incidental findings on radiologic or postmortem examinations, although some small, slow-growing lesions with excessive hormonal activity may manifest with a clinical syndrome. The family of neurotrophins plays a key role in the development and maintenance of the pituitary endocrine cell function and in the regulation of hypothalamo-pituitary-adrenocortical axis activity. The objective of our experimental study is to investigate the localization of the neurotrophins, their relative receptors and to detect the expression level of Ki-67 to determine whether all these factors participate in the transformation and development of human pituitary adenomas. A very strong expression of Neurotrophin-3 (NT-3) and its receptor TrKC was observed in the extracellular matrix (ECM) and vessel endothelium, together with a clear/marked presence of Brain-derived neurotrophic factor (BDNF), and its receptor TrKB, thus confirming their direct involvement in the progression of pituitary adenomas. On the contrary, NGF (Nerve growth factor) and its receptor TrKA and p75NTR were weakly expressed in the epithelial gland cells and the ECM.

Platelet-derived growth factor receptor mediates activation of ras through different signaling pathways in different cell types.

PubMed Central

Satoh, T; Fantl, W J; Escobedo, J A; Williams, L T; Kaziro, Y

1993-01-01

A series of pieces of evidence have shown that Ras protein acts as a transducer of the platelet-derived growth factor (PDGF) receptor-mediated signaling pathway: (i) formation of Ras.GTP is detected immediately on PDGF stimulation, and (ii) a dominant inhibitory mutant Ras, as well as a neutralizing anti-Ras antibody, can interfere with PDGF-induced responses. On the other hand, several signal transducing molecules including phosphatidylinositol 3-kinase (PI3-K), GTPase-activating protein (GAP), and phospholipase C gamma (PLC gamma) bind directly to the PDGF receptor and become tyrosine phosphorylated. Recently, it was shown that specific phosphorylated tyrosines of the PDGF receptor are responsible for interaction between the receptor and each signaling molecule. However, the roles of these signaling molecules have not been elucidated, and it remains unclear which molecules are implicated in the Ras pathway. In this study, we measured Ras activation in cell lines expressing mutant PDGF receptors that are deficient in coupling with specific molecules. In fibroblast CHO cells, a mutant receptor (Y708F/Y719F [PI3-K-binding sites]) was unable to stimulate Ras, whereas another mutant (Y739F [the GAP-binding site]) could do so, suggesting an indispensable role of PI3-K or a protein that binds to the same sites as PI3-K for PDGF-stimulated Ras activation. By contrast, both of the above mutants were capable of stimulating Ras protein in a pro-B-cell line, BaF3. Furthermore, a mutant receptor (Y977F/Y989F [PLC gamma-binding sites]) could fully activate Ras, and the direct activation of protein kinase C and calcium mobilization had almost no effect on the GDP/GTP state of Ras in this cell line. These results suggest that, in the pro-B-cell transfectants, each of the above pathways (PI3-K, GAP, and PLC gamma) can be eliminated without a loss of Ras activation. It remains unclear whether another unknown essential pathway which regulates Ras protein exists within BaF3 cells. Therefore, it is likely that several different PDGF receptor-mediated signaling pathways function upstream of Ras, and the extent of the contribution of each pathway for the regulation of Ras may differ among different cell types. Images PMID:8388543

The 150 most important questions in cancer research and clinical oncology series: questions 50-56.

PubMed

2017-08-29

Since the beginning of 2017, Chinese Journal of Cancer has published a series of important questions in cancer research and clinical oncology, which sparkle diverse thoughts, interesting communications, and potential collaborations among researchers all over the world. In this article, seven more questions are presented as followed. Question 50. When tumor cells spread from primary site to distant sites, are they required to be "trained" or "armed" in the bone marrow niche prior to colonizing soft tissues? Question 51. Are there tipping points during cancer progression which can be identified for manipulation? Question 52. Can we replace molecular biomarkers by network biomarkers? Question 53. Are conventional inhibitors of key cellular processes such as cell proliferation and differentiation more effective than targeted chemotherapeutics that antagonize the downstream cell signaling network via cell-surface receptors such as epidermal growth factor receptor (EGFR), vascular endothelial growth factor receptor (VEGFR) and c-Met, or intracellular receptors such as androgen receptor (AR) and estrogen receptor (ER), by drugs like erlotinib, sunitinib and cabozantinib, or enzalutamide and tomoxifen? Question 54. How can we robustly identify the candidate causal event of somatic genome alteration (SGA) by using computational approach? Question 55. How can we systematically reveal the immune evasion mechanism exploited by each tumor and utilize such information to guide targeted therapy to restore immune sensitivity? Question 56. Can the nasopharyngeal carcinoma (NPC) patients with sarcomatoid carcinoma (SC) subtype benefit from more specific targeted therapy?

Phosphatidylserine Sensing by TAM Receptors Regulates AKT-Dependent Chemoresistance and PD-L1 Expression.

PubMed

Kasikara, Canan; Kumar, Sushil; Kimani, Stanley; Tsou, Wen-I; Geng, Ke; Davra, Viralkumar; Sriram, Ganapathy; Devoe, Connor; Nguyen, Khanh-Quynh N; Antes, Anita; Krantz, Allen; Rymarczyk, Grzegorz; Wilczynski, Andrzej; Empig, Cyril; Freimark, Bruce; Gray, Michael; Schlunegger, Kyle; Hutchins, Jeff; Kotenko, Sergei V; Birge, Raymond B

2017-06-01

Tyro3, Axl, and Mertk (collectively TAM receptors) are three homologous receptor tyrosine kinases that bind vitamin K-dependent endogenous ligands, Protein S (ProS), and growth arrest-specific factor 6 (Gas6), and act as bridging molecules to promote phosphatidylserine (PS)-mediated clearance of apoptotic cells (efferocytosis). TAM receptors are overexpressed in a vast array of tumor types, whereby the level of expression correlates with the tumor grade and the emergence of chemo- and radioresistance to targeted therapeutics, but also have been implicated as inhibitory receptors on infiltrating myeloid-derived cells in the tumor microenvironment that can suppress host antitumor immunity. In the present study, we utilized TAM-IFNγR1 reporter lines and expressed TAM receptors in a variety of epithelial cell model systems to show that each TAM receptor has a unique pattern of activation by Gas6 or ProS, as well as unique dependency for PS on apoptotic cells and PS liposomes for activity. In addition, we leveraged this system to engineer epithelial cells that express wild-type TAM receptors and show that although each receptor can promote PS-mediated efferocytosis, AKT-mediated chemoresistance, as well as upregulate the immune checkpoint molecule PD-L1 on tumor cells, Mertk is most dominant in the aforementioned pathways. Functionally, TAM receptor-mediated efferocytosis could be partially blocked by PS-targeting antibody 11.31 and Annexin V, demonstrating the existence of a PS/PS receptor (i.e., TAM receptor)/PD-L1 axis that operates in epithelial cells to foster immune escape. These data provide a rationale that PS-targeting, anti-TAM receptor, and anti-PD-L1-based therapeutics will have merit as combinatorial checkpoint inhibitors. Implications: Many tumor cells are known to upregulate the immune checkpoint inhibitor PD-L1. This study demonstrates a role for PS and TAM receptors in the regulation of PD-L1 on cancer cells. Mol Cancer Res; 15(6); 753-64. ©2017 AACR . ©2017 American Association for Cancer Research.

Combined inhibition of EMMPRIN and epidermal growth factor receptor prevents the growth and migration of head and neck squamous cell carcinoma cells.

PubMed

Suzuki, Shinsuke; Ishikawa, Kazuo

2014-03-01

It has been reported that the epidermal growth factor receptor (EGFR) expression is associated with the extracellular matrix metalloproteinase inducer (EMMPRIN) in some solid tumors; however, the relationship of EMMPRIN with EGFR in head and neck cancers is not fully understood. To determine the relationship between EMMPRIN and EGFR in head and neck squamous cell carcinoma (HNSCC), HNSCC cells were stimulated with epidermal growth factor (EGF), a ligand of EGFR. EMMPRIN expression in HNSCC cells was upregulated by EGF. In addition, EGF stimulation induced HNSCC cell invasion and MMP-9 expression. This increase in invasion and MMP-9 expression was abrogated by downmodulation of EMMPRIN. Furthermore, to determine the effects of combined EMMPRIN and EGFR targeting in HNSCC, HNSCC cells were treated with an EMMPRIN function-blocking antibody and the EGFR inhibitor AG1478. This combined treatment resulted in greater inhibition of HNSCC cell proliferation and migration compared with the individual agents alone. These results suggest that EMMPRIN mediates EGFR-induced tumorigenicity and that combined targeting of EMMPRIN and EGFR may be an efficacious treatment approach.

Engineering growth factors for regenerative medicine applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitchell, Aaron C.; Briquez, Priscilla S.; Hubbell, Jeffrey A.

Growth factors are important morphogenetic proteins that instruct cell behavior and guide tissue repair and renewal. Although their therapeutic potential holds great promise in regenerative medicine applications, translation of growth factors into clinical treatments has been hindered by limitations including poor protein stability, low recombinant expression yield, and suboptimal efficacy. This review highlights current tools, technologies, and approaches to design integrated and effective growth factor-based therapies for regenerative medicine applications. The first section describes rational and combinatorial protein engineering approaches that have been utilized to improve growth factor stability, expression yield, biodistribution, and serum half-life, or alter their cell traffickingmore » behavior or receptor binding affinity. The second section highlights elegant biomaterial-based systems, inspired by the natural extracellular matrix milieu, that have been developed for effective spatial and temporal delivery of growth factors to cell surface receptors. Although appearing distinct, these two approaches are highly complementary and involve principles of molecular design and engineering to be considered in parallel when developing optimal materials for clinical applications.« less

Leiomyoma-derived transforming growth factor-β impairs bone morphogenetic protein-2-mediated endometrial receptivity.

PubMed

Doherty, Leo F; Taylor, Hugh S

2015-03-01

To determine whether transforming growth factor (TGF)-β3 is a paracrine signal secreted by leiomyoma that inhibits bone morphogenetic protein (BMP)-mediated endometrial receptivity and decidualization. Experimental. Laboratory. Women with symptomatic leiomyomas. Endometrial stromal cells (ESCs) and leiomyoma cells were isolated from surgical specimens. Leiomyoma-conditioned media (LCM) was applied to cultured ESC. The TGF-β was blocked by two approaches: TGF-β pan-specific antibody or transfection with a mutant TGF-β receptor type II. Cells were then treated with recombinant human BMP-2 to assess BMP responsiveness. Expression of BMP receptor types 1A, 1B, 2, as well as endometrial receptivity mediators HOXA10 and leukemia inhibitory factor (LIF). Enzyme-linked immunosorbent assay showed elevated TGF-β levels in LCM. LCM treatment of ESC reduced expression of BMP receptor types 1B and 2 to approximately 60% of pretreatment levels. Preincubation of LCM with TGF-β neutralizing antibody or mutant TGF receptor, but not respective controls, prevented repression of BMP receptors. HOXA10 and LIF expression was repressed in recombinant human BMP-2 treated, LCM exposed ESC. Pretreatment of LCM with TGF-β antibody or transfection with mutant TGF receptor prevented HOXA10 and LIF repression. Leiomyoma-derived TGF-β was necessary and sufficient to alter endometrial BMP-2 responsiveness. Blockade of TGF-β prevents repression of BMP-2 receptors and restores BMP-2-stimulated expression of HOXA10 and LIF. Blockade of TGF signaling is a potential strategy to improve infertility and pregnancy loss associated with uterine leiomyoma. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

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

2014-03-05

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. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

The transcriptional co-factor RIP140 regulates mammary gland development by promoting the generation of key mitogenic signals.

PubMed

Nautiyal, Jaya; Steel, Jennifer H; Mane, Meritxell Rosell; Oduwole, Olayiwola; Poliandri, Ariel; Alexi, Xanthippi; Wood, Nicholas; Poutanen, Matti; Zwart, Wilbert; Stingl, John; Parker, Malcolm G

2013-03-01

Nuclear receptor interacting protein (Nrip1), also known as RIP140, is a co-regulator for nuclear receptors that plays an essential role in ovulation by regulating the expression of the epidermal growth factor-like family of growth factors. Although several studies indicate a role for RIP140 in breast cancer, its role in the development of the mammary gland is unclear. By using RIP140-null and RIP140 transgenic mice, we demonstrate that RIP140 is an essential factor for normal mammary gland development and that it functions by mediating oestrogen signalling. RIP140-null mice exhibit minimal ductal elongation with no side-branching, whereas RIP140-overexpressing mice show increased cell proliferation and ductal branching with age. Tissue recombination experiments demonstrate that RIP140 expression is required in both the mammary epithelial and stromal compartments for ductal elongation during puberty and that loss of RIP140 leads to a catastrophic loss of the mammary epithelium, whereas RIP140 overexpression augments the mammary basal cell population and shifts the progenitor/differentiated cell balance within the luminal cell compartment towards the progenitors. For the first time, we present a genome-wide global view of oestrogen receptor-α (ERα) binding events in the developing mammary gland, which unravels 881 ERα binding sites. Unbiased evaluation of several ERα binding sites for RIP140 co-occupancy reveals selectivity and demonstrates that RIP140 acts as a co-regulator with ERα to regulate directly the expression of amphiregulin (Areg), the progesterone receptor (Pgr) and signal transducer and activator of transcription 5a (Stat5a), factors that influence key mitogenic pathways that regulate normal mammary gland development.

Flipped script for gefitinib: A reapproved tyrosine kinase inhibitor for first-line treatment of epidermal growth factor receptor mutation positive metastatic nonsmall cell lung cancer.

PubMed

Bogdanowicz, Brian S; Hoch, Matthew A; Hartranft, Megan E

2017-04-01

Purpose The approval history, pharmacology, pharmacokinetics, clinical trials, efficacy, dosing recommendations, drug interactions, safety, place in therapy, and economic considerations of gefitinib are reviewed. Summary Lung cancer is one of the most commonly diagnosed cancers and is the leading cause of cancer death. Platinum-based chemotherapy and tyrosine kinase inhibitors, such as erlotinib and afatinib, are recommended therapies for nonsmall cell lung cancer. The European Medicines Association based their approval of gefitinib on the randomized, multicenter Iressa Pan-Asia Study (IPASS, NCT00322452) and a single-arm study showing effectiveness in Caucasians (IFUM, NCT01203917). Both studies were recently referenced by the United States Food & Drug Administration to reapprove gefitinib for the first-line treatment of advanced nonsmall cell lung cancer with epidermal growth factor receptor exon 19 deletions or exon 21 substitution. Diarrhea, acneiform rash, and interstitial lung disease are known side effects of gefitinib. Conclusion Use of gefitinib for the first-line therapy of metastatic nonsmall cell lung cancer with epidermal growth factor receptor exon 19 deletions (residues 747-750) or exon 21 substitution mutation (L858R) is well-documented and supported.

Nuclear translocation of IGF1R by intracellular amphiregulin contributes to the resistance of lung tumour cells to EGFR-TKI.

PubMed

Guerard, Marie; Robin, Thomas; Perron, Pascal; Hatat, Anne-Sophie; David-Boudet, Laurence; Vanwonterghem, Laetitia; Busser, Benoit; Coll, Jean-Luc; Lantuejoul, Sylvie; Eymin, Beatrice; Hurbin, Amandine; Gazzeri, Sylvie

2018-04-28

Many Receptor Tyrosine Kinases translocate from the cell surface to the nucleus in normal and pathological conditions, including cancer. Here we report the nuclear expression of insulin-like growth factor-1 receptor (IGF1R) in primary human lung tumours. Using lung cancer cell lines and lung tumour xenografts, we demonstrate that the epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) gefitinib induces the nuclear accumulation of IGF1R in mucinous lung adenocarcinoma by a mechanism involving the intracellular re-localization of the growth factor amphiregulin. Amphiregulin allows the binding of IGF1R to importin-β1 and promotes its nuclear transport. The nuclear accumulation of IGF1R by amphiregulin induces cell cycle arrest through p21 WAF1/CIP1 upregulation, and prevents the induction of apoptosis in response to gefitinib. These results identify amphiregulin as the first nuclear localization signal-containing protein that interacts with IGF1R and allows its nuclear translocation. Furthermore they indicate that nuclear expression of IGF1R contributes to EGFR-TKI resistance in lung cancer. Copyright © 2018 Elsevier B.V. All rights reserved.

Plant GSK3 proteins regulate xylem cell differentiation downstream of TDIF-TDR signalling

NASA Astrophysics Data System (ADS)

Kondo, Yuki; Ito, Tasuku; Nakagami, Hirofumi; Hirakawa, Yuki; Saito, Masato; Tamaki, Takayuki; Shirasu, Ken; Fukuda, Hiroo

2014-03-01

During plant radial growth typically seen in trees, procambial and cambial cells act as meristematic cells in the vascular system to self-proliferate and differentiate into xylem cells. These two processes are regulated by a signalling pathway composed of a peptide ligand and its receptor; tracheary element differentiation inhibitory factor (TDIF) and TDIF RECEPTOR (TDR). Here we show that glycogen synthase kinase 3 proteins (GSK3s) are crucial downstream components of the TDIF signalling pathway suppressing xylem differentiation from procambial cells. TDR interacts with GSK3s at the plasma membrane and activates GSK3s in a TDIF-dependent fashion. Consistently, a specific inhibitor of plant GSK3s strongly induces xylem cell differentiation through BRI1-EMS SUPPRESSOR 1 (BES1), a well-known target transcription factor of GSK3s. Our findings provide insight into the regulation of cell fate determination in meristem maintenance.

Vascular Repair After Menstruation Involves Regulation of Vascular Endothelial Growth Factor-Receptor Phosphorylation by sFLT-1

PubMed Central

Graubert, Michael D.; Asuncion Ortega, Maria; Kessel, Bruce; Mortola, Joseph F.; Iruela-Arispe, M. Luisa

2001-01-01

Regeneration of the endometrium after menstruation requires a rapid and highly organized vascular response. Potential regulators of this process include members of the vascular endothelial growth factor (VEGF) family of proteins and their receptors. Although VEGF expression has been detected in the endometrium, the relationship between VEGF production, receptor activation, and endothelial cell proliferation during the endometrial cycle is poorly understood. To better ascertain the relevance of VEGF family members during postmenstrual repair, we have evaluated ligands, receptors, and activity by receptor phosphorylation in human endometrium throughout the menstrual cycle. We found that VEGF is significantly increased at the onset of menstruation, a result of the additive effects of hypoxia, transforming growth factor-α, and interleukin-1β. Both VEGF receptors, FLT-1 and KDR, followed a similar pattern. However, functional activity of KDR, as determined by phosphorylation studies, revealed activation in the late menstrual and early proliferative phases. The degree of KDR phosphorylation was inversely correlated with the presence of sFLT-1. Endothelial cell proliferation analysis in endometrium showed a peak during the late menstrual and early proliferative phases in concert with the presence of VEGF, VEGF receptor phosphorylation, and decrease of sFLT-1. Together, these results suggest that VEGF receptor activation and the subsequent modulation of sFLT-1 in the late menstrual phase likely contributes to the onset of angiogenesis and endothelial repair in the human endometrium. PMID:11290558

Anti-cancer stemness and anti-invasive activity of bitter taste receptors, TAS2R8 and TAS2R10, in human neuroblastoma cells.

PubMed

Seo, Yoona; Kim, Yoo-Sun; Lee, Kyung Eun; Park, Tai Hyun; Kim, Yuri

2017-01-01

Neuroblastoma (NB) originates from immature neuronal cells and currently has a poor clinical outcome. NB cells possess cancer stem cells (CSCs) characteristics that facilitate the initiation of a tumor, as well as its metastasis. Human bitter taste receptors, referred to as TAS2Rs, are one of five types of basic taste receptors and they belong to a family of G-protein coupled receptors. The recent finding that taste receptors are expressed in non-gustatory tissues suggest that they mediate additional functions distinct from taste perception. While it is generally admitted that the recognition of bitter tastes may be associated with a self-defense system to prevent the ingestion of poisonous food compounds, this recognition may also serve as a disease-related function in the human body. In particular, the anti-cancer stemness and invasion effects of TAS2Rs on NB cells remain poorly understood. In the present study, endogenous expression of TAS2R8 and TAS2R10 in SK-N-BE(2)C and SH-SY5Y cells was examined. In addition, higher levels of TAS2R8 and TAS2R10 expression were investigated in more differentiated SY5Y cells. Both TAS2Rs were up-regulated following the induction of neuronal cell differentiation by retinoic acid. In addition, ectopic transfection of the two TAS2Rs induced neurite elongation in the BE(2)C cells, and down-regulated CSCs markers (including DLK1, CD133, Notch1, and Sox2), and suppressed self-renewal characteristics. In particular, TAS2RS inhibited tumorigenicity. Furthermore, when TAS2Rs was over-expressed, cell migration, cell invasion, and matrix metalloproteinases activity were inhibited. Expression levels of hypoxia-inducible factor-1α, a well-known regulator of tumor metastasis, as well as its downstream targets, vascular endothelial growth factor and glucose transporter-1, were also suppressed by TAS2Rs. Taken together, these novel findings suggest that TAS2Rs targets CSCs by suppressing cancer stemness characteristics and NB cell invasion, thereby highlighting the chemotherapeutic potential of bitter taste receptors.

Anti-cancer stemness and anti-invasive activity of bitter taste receptors, TAS2R8 and TAS2R10, in human neuroblastoma cells

PubMed Central

Seo, Yoona; Kim, Yoo-Sun; Lee, Kyung Eun; Park, Tai Hyun; Kim, Yuri

2017-01-01

Neuroblastoma (NB) originates from immature neuronal cells and currently has a poor clinical outcome. NB cells possess cancer stem cells (CSCs) characteristics that facilitate the initiation of a tumor, as well as its metastasis. Human bitter taste receptors, referred to as TAS2Rs, are one of five types of basic taste receptors and they belong to a family of G-protein coupled receptors. The recent finding that taste receptors are expressed in non-gustatory tissues suggest that they mediate additional functions distinct from taste perception. While it is generally admitted that the recognition of bitter tastes may be associated with a self-defense system to prevent the ingestion of poisonous food compounds, this recognition may also serve as a disease-related function in the human body. In particular, the anti-cancer stemness and invasion effects of TAS2Rs on NB cells remain poorly understood. In the present study, endogenous expression of TAS2R8 and TAS2R10 in SK-N-BE(2)C and SH-SY5Y cells was examined. In addition, higher levels of TAS2R8 and TAS2R10 expression were investigated in more differentiated SY5Y cells. Both TAS2Rs were up-regulated following the induction of neuronal cell differentiation by retinoic acid. In addition, ectopic transfection of the two TAS2Rs induced neurite elongation in the BE(2)C cells, and down-regulated CSCs markers (including DLK1, CD133, Notch1, and Sox2), and suppressed self-renewal characteristics. In particular, TAS2RS inhibited tumorigenicity. Furthermore, when TAS2Rs was over-expressed, cell migration, cell invasion, and matrix metalloproteinases activity were inhibited. Expression levels of hypoxia-inducible factor-1α, a well-known regulator of tumor metastasis, as well as its downstream targets, vascular endothelial growth factor and glucose transporter-1, were also suppressed by TAS2Rs. Taken together, these novel findings suggest that TAS2Rs targets CSCs by suppressing cancer stemness characteristics and NB cell invasion, thereby highlighting the chemotherapeutic potential of bitter taste receptors. PMID:28467517

Dexmedetomidine Prevents Excessive γ-Aminobutyric Acid Type A Receptor Function after Anesthesia.

PubMed

Wang, Dian-Shi; Kaneshwaran, Kirusanthy; Lei, Gang; Mostafa, Fariya; Wang, Junhui; Lecker, Irene; Avramescu, Sinziana; Xie, Yu-Feng; Chan, Nathan K; Fernandez-Escobar, Alejandro; Woo, Junsung; Chan, Darren; Ramsey, Amy J; Sivak, Jeremy M; Lee, C Justin; Bonin, Robert P; Orser, Beverley A

2018-06-08

Postoperative delirium is associated with poor long-term outcomes and increased mortality. General anesthetic drugs may contribute to delirium because they increase cell-surface expression and function of α5 subunit-containing γ-aminobutyric acid type A receptors, an effect that persists long after the drugs have been eliminated. Dexmedetomidine, an α2 adrenergic receptor agonist, prevents delirium in patients and reduces cognitive deficits in animals. Thus, it was postulated that dexmedetomidine prevents excessive function of α5 γ-aminobutyric acid type A receptors. Injectable (etomidate) and inhaled (sevoflurane) anesthetic drugs were studied using cultured murine hippocampal neurons, cultured murine and human cortical astrocytes, and ex vivo murine hippocampal slices. γ-Aminobutyric acid type A receptor function and cell-signaling pathways were studied using electrophysiologic and biochemical methods. Memory and problem-solving behaviors were also studied. The etomidate-induced sustained increase in α5 γ-aminobutyric acid type A receptor cell-surface expression was reduced by dexmedetomidine (mean ± SD, etomidate: 146.4 ± 51.6% vs. etomidate + dexmedetomidine: 118.4 ± 39.1% of control, n = 8 each). Dexmedetomidine also reduced the persistent increase in tonic inhibitory current in hippocampal neurons (etomidate: 1.44 ± 0.33 pA/pF, n = 10; etomidate + dexmedetomidine: 1.01 ± 0.45 pA/pF, n = 9). Similarly, dexmedetomidine prevented a sevoflurane-induced increase in the tonic current. Dexmedetomidine stimulated astrocytes to release brain-derived neurotrophic factor, which acted as a paracrine factor to reduce excessive α5 γ-aminobutyric acid type A receptor function in neurons. Finally, dexmedetomidine attenuated memory and problem-solving deficits after anesthesia. Dexmedetomidine prevented excessive α5 γ-aminobutyric acid type A receptor function after anesthesia. This novel α2 adrenergic receptor- and brain-derived neurotrophic factor-dependent pathway may be targeted to prevent delirium.

Design and characteristics of cytotoxic fibroblast growth factor 1 conjugate for fibroblast growth factor receptor-targeted cancer therapy.

PubMed

Szlachcic, Anna; Zakrzewska, Malgorzata; Lobocki, Michal; Jakimowicz, Piotr; Otlewski, Jacek

2016-01-01

Fibroblast growth factor receptors (FGFRs) are attractive candidate cancer therapy targets as they are overexpressed in multiple types of tumors, such as breast, prostate, bladder, and lung cancer. In this study, a natural ligand of FGFR, an engineered variant of fibroblast growth factor 1 (FGF1V), was conjugated to a potent cytotoxic drug, monomethyl auristatin E (MMAE), and used as a targeting agent for cancer cells overexpressing FGFRs, similar to antibodies in antibody-drug conjugates. The FGF1V-valine-citrulline-MMAE conjugate showed a favorable stability profile, bound FGFRs on the cell surface specifically, and efficiently released the drug (MMAE) upon cleavage by the lysosomal protease cathepsin B. Importantly, the conjugate showed a prominent cytotoxic effect toward cell lines expressing FGFR. FGF1V-vcMMAE was highly cytotoxic at concentrations even an order of magnitude lower than those found for free MMAE. This effect was FGFR-specific as cells lacking FGFR did not show any increased mortality.

Design and characteristics of cytotoxic fibroblast growth factor 1 conjugate for fibroblast growth factor receptor-targeted cancer therapy

PubMed Central

Szlachcic, Anna; Zakrzewska, Malgorzata; Lobocki, Michal; Jakimowicz, Piotr; Otlewski, Jacek

2016-01-01

Fibroblast growth factor receptors (FGFRs) are attractive candidate cancer therapy targets as they are overexpressed in multiple types of tumors, such as breast, prostate, bladder, and lung cancer. In this study, a natural ligand of FGFR, an engineered variant of fibroblast growth factor 1 (FGF1V), was conjugated to a potent cytotoxic drug, monomethyl auristatin E (MMAE), and used as a targeting agent for cancer cells overexpressing FGFRs, similar to antibodies in antibody–drug conjugates. The FGF1V–valine–citrulline–MMAE conjugate showed a favorable stability profile, bound FGFRs on the cell surface specifically, and efficiently released the drug (MMAE) upon cleavage by the lysosomal protease cathepsin B. Importantly, the conjugate showed a prominent cytotoxic effect toward cell lines expressing FGFR. FGF1V–vcMMAE was highly cytotoxic at concentrations even an order of magnitude lower than those found for free MMAE. This effect was FGFR-specific as cells lacking FGFR did not show any increased mortality. PMID:27563235

Mechanical stretch augments insulin-induced vascular smooth muscle cell proliferation by insulin-like growth factor-1 receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Gang; Department of Anesthesiology, First Affiliated Hospital of China Medical University, Shenyang; Hitomi, Hirofumi, E-mail: hitomi@kms.ac.jp

Insulin resistance and hypertension have been implicated in the pathogenesis of cardiovascular disease; however, little is known about the roles of insulin and mechanical force in vascular smooth muscle cell (VSMC) remodeling. We investigated the contribution of mechanical stretch to insulin-induced VSMC proliferation. Thymidine incorporation was stimulated by insulin in stretched VSMCs, but not in un-stretched VSMCs. Insulin increased 2-deoxy-glucose incorporation in both stretched and un-stretched VSMCs. Mechanical stretch augmented insulin-induced extracellular signal-regulated kinase (ERK) and Akt phosphorylation. Inhibitors of epidermal growth factor (EGF) receptor tyrosine kinase and Src attenuated insulin-induced ERK and Akt phosphorylation, as well as thymidine incorporation,more » whereas 2-deoxy-glucose incorporation was not affected by these inhibitors. Moreover, stretch augmented insulin-like growth factor (IGF)-1 receptor expression, although it did not alter the expression of insulin receptor and insulin receptor substrate-1. Insulin-induced ERK and Akt activation, and thymidine incorporation were inhibited by siRNA for the IGF-1 receptor. Mechanical stretch augments insulin-induced VSMC proliferation via upregulation of IGF-1 receptor, and downstream Src/EGF receptor-mediated ERK and Akt activation. Similar to in vitro experiment, IGF-1 receptor expression was also augmented in hypertensive rats. These results provide a basis for clarifying the molecular mechanisms of vascular remodeling in hypertensive patients with hyperinsulinemia. -- Highlights: {yields} Mechanical stretch augments insulin-induced VSMC proliferation via IGF-1 receptor. {yields} Src/EGFR-mediated ERK and Akt phosphorylation are augmented in stretched VSMCs. {yields} Similar to in vitro experiment, IGF-1 receptor is increased in hypertensive rats. {yields} Results provide possible mechanisms of vascular remodeling in hypertension with DM.« less

Aldosterone interaction with epidermal growth factor receptor signaling in MDCK cells.

PubMed

Gekle, Michael; Freudinger, Ruth; Mildenberger, Sigrid; Silbernagl, Stefan

2002-04-01

Epidermal growth factor (EGF) regulates cell proliferation, differentiation, and ion transport by using extracellular signal-regulated kinase (ERK)1/2 as a downstream signal. Furthermore, the EGF-receptor (EGF-R) is involved in signaling by G protein-coupled receptors, growth hormone, and cytokines by means of transactivation. It has been suggested that steroids interact with peptide hormones, in part, by rapid, potentially nongenomic, mechanisms. Previously, we have shown that aldosterone modulates Na(+)/H(+) exchange in Madin-Darby canine kidney (MDCK) cells by means of ERK1/2 in a way similar to growth factors. Here, we tested the hypothesis that aldosterone uses the EGF-R as a heterologous signal transducer in MDCK cells. Nanomolar concentrations of aldosterone induce a rapid increase in ERK1/2 phosphorylation, cellular Ca(2+) concentration, and Na(+)/H(+) exchange activity similar to increases induced by EGF. Furthermore, aldosterone induced a rapid increase in EGF-R-Tyr phosphorylation, and inhibition of EGF-R kinase abolished aldosterone-induced signaling. Inhibition of ERK1/2 phosphorylation reduced the Ca(2+) response, whereas prevention of Ca(2+) influx did not abolish ERK1/2 phosphorylation. Our data show that aldosterone uses the EGF-R-ERK1/2 signaling cascade to elicit its rapid effects in MDCK cells.

Cell surface retention sequence binding protein-1 interacts with the v-sis gene product and platelet-derived growth factor beta-type receptor in simian sarcoma virus-transformed cells.

PubMed

Boensch, C; Huang, S S; Connolly, D T; Huang, J S

1999-04-09

The cell surface retention sequence (CRS) binding protein-1 (CRSBP-1) is a newly identified membrane glycoprotein which is hypothesized to be responsible for cell surface retention of the oncogene v-sis and c-sis gene products and other secretory proteins containing CRSs. In simian sarcoma virus-transformed NIH 3T3 cells (SSV-NIH 3T3 cells), a fraction of CRSBP-1 was demonstrated at the cell surface and underwent internalization/recycling as revealed by cell surface 125I labeling and its resistance/sensitivity to trypsin digestion. However, the majority of CRSBP-1 was localized in intracellular compartments as evidenced by the resistance of most of the 35S-metabolically labeled CRSBP-1 to trypsin digestion, and by indirect immunofluorescent staining. CRSBP-1 appeared to form complexes with proteolytically processed forms (generated at and/or after the trans-Golgi network) of the v-sis gene product and with a approximately 140-kDa proteolytically cleaved form of the platelet-derived growth factor (PDGF) beta-type receptor, as demonstrated by metabolic labeling and co-immunoprecipitation. CRSBP-1, like the v-sis gene product and PDGF beta-type receptor, underwent rapid turnover which was blocked in the presence of 100 microM suramin. In normal and other transformed NIH 3T3 cells, CRSBP-1 was relatively stable and did not undergo rapid turnover and internalization/recycling at the cell surface. These results suggest that in SSV-NIH 3T3 cells, CRSBP-1 interacts with and forms ternary and binary complexes with the newly synthesized v-sis gene product and PDGF beta-type receptor at the trans-Golgi network and that the stable binary (CRSBP-1.v-sis gene product) complex is transported to the cell surface where it presents the v-sis gene product to unoccupied PDGF beta-type receptors during internalization/recycling.

A potential oncogenic activity of platelet-derived growth factor d in prostate cancer progression.

PubMed

Ustach, Carolyn V; Taube, Marcus E; Hurst, Newton J; Bhagat, Sunita; Bonfil, R Daniel; Cher, Michael L; Schuger, Lucia; Kim, Hyeong-Reh Choi

2004-03-01

The platelet-derived growth factor (PDGF) proteins are potent stimulators of cell proliferation/transformation and play a major role in cell-cell communication. For over two decades, PDGFs were thought to exist as three dimeric polypeptides (the homodimers AA and BB and the heterodimer AB). Recently, however, the PDGF C and D chains were discovered in a BLAST search of the expressed sequence tag databases. The PDGF CC and DD dimers have a unique two-domain structure with an NH(2)-terminal CUB (compliment subcomponents C1r/C1s, Uegf, and Bmp1) domain and a COOH-terminal PDGF/vascular endothelial growth factor domain. Whereas secreted PDGF AA, BB, and AB readily activate their cell surface receptors, it was suggested that extracellular proteolytic removal of the CUB domain is required for the PDGF/vascular endothelial growth factor domain of PDGF CC and DD to activate PDGF receptors. In the present study, we examined the processing of latent PDGF D into its active form and the effects of PDGF D expression on prostate cancer progression. We show that LNCaP cells auto-activate latent PDGF DD into the active PDGF domain, which can induce phosphorylation of the beta-PDGF receptor and stimulates LNCaP cell proliferation in an autocrine manner. Additionally, LNCaP-PDGF D-conditioned medium induces migration of the prostate fibroblast cell line 1532-FTX, indicating LNCaP-processed PDGF DD is active in a paracrine manner as well. In a severe combined immunodeficient mouse model, PDGF DD expression accelerates early onset of prostate tumor growth and drastically enhances prostate carcinoma cell interaction with surrounding stromal cells. These demonstrate a potential oncogenic activity of PDGF DD in the development and/or progression of prostate cancer.

A Potential Oncogenic Activity of Platelet-Derived Growth Factor D in Prostate Cancer Progression

PubMed Central

Ustach, Carolyn V.; Taube, Marcus E.; Hurst, Newton J.; Bhagat, Sunita; Bonfil, R. Daniel; Cher, Michael L.; Schuger, Lucia; Kim, Hyeong-Reh Choi

2014-01-01

The platelet-derived growth factor (PDGF) proteins are potent stimulators of cell proliferation/transformation and play a major role in cell-cell communication. For over two decades, PDGFs were thought to exist as three dimeric polypeptides (the homodimers AA and BB and the heterodimer AB). Recently, however, the PDGF C and D chains were discovered in a BLAST search of the expressed sequence tag databases. The PDGF CC and DD dimers have a unique two-domain structure with an NH2-terminal CUB (compliment subcomponents C1r/C1s, Uegf, and Bmp1) domain and a COOH-terminal PDGF/vascular endothelial growth factor domain. Whereas secreted PDGF AA, BB, and AB readily activate their cell surface receptors, it was suggested that extracellular proteolytic removal of the CUB domain is required for the PDGF/vascular endothelial growth factor domain of PDGF CC and DD to activate PDGF receptors. In the present study, we examined the processing of latent PDGF D into its active form and the effects of PDGF D expression on prostate cancer progression. We show that LNCaP cells auto-activate latent PDGF DD into the active PDGF domain, which can induce phosphorylation of the β-PDGF receptor and stimulates LNCaP cell proliferation in an autocrine manner. Additionally, LNCaP-PDGF D-conditioned medium induces migration of the prostate fibroblast cell line 1532-FTX, indicating LNCaP-processed PDGF DD is active in a paracrine manner as well. In a severe combined immunodeficient mouse model, PDGF DD expression accelerates early onset of prostate tumor growth and drastically enhances prostate carcinoma cell interaction with surrounding stromal cells. These demonstrate a potential oncogenic activity of PDGF DD in the development and/or progression of prostate cancer. PMID:14996732

Decoy receptors block TRAIL sensitivity at a supracellular level: the role of stromal cells in controlling tumour TRAIL sensitivity.

PubMed

O'Leary, L; van der Sloot, A M; Reis, C R; Deegan, S; Ryan, A E; Dhami, S P S; Murillo, L S; Cool, R H; Correa de Sampaio, P; Thompson, K; Murphy, G; Quax, W J; Serrano, L; Samali, A; Szegezdi, E

2016-03-10

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a death ligand cytokine known for its cytotoxic activity against malignantly transformed cells. TRAIL induces cell death through binding to death receptors DR4 and DR5. The inhibitory decoy receptors (DcR1 and DcR2) co-expressed with death receptor 4 (DR4)/DR5 on the same cell can block the transmission of the apoptotic signal. Here, we show that DcRs also regulate TRAIL sensitivity at a supracellular level and thus represent a mechanism by which the microenvironment can diminish tumour TRAIL sensitivity. Mathematical modelling and layered or spheroid stroma-extracellular matrix-tumour cultures were used to model the tumour microenvironment. By engineering TRAIL to escape binding by DcRs, we found that DcRs do not only act in a cell-autonomous or cis-regulatory manner, but also exert trans-cellular regulation originating from stromal cells and affect tumour cells, highlighting the potent inhibitory effect of DcRs in the tumour tissue and the necessity of selective targeting of the two death-inducing TRAIL receptors to maximise efficacy.

Tumor microenvironment: Modulation by decorin and related molecules harboring leucine-rich tandem motifs.

PubMed

Goldoni, Silvia; Iozzo, Renato V

2008-12-01

Decorin, the prototype member of the small leucine-rich proteoglycans, resides in the tumor microenvironment and affects the biology of various types of cancer by downregulating the activity of several receptors involved in cell growth and survival. Decorin binds to and modulates the signaling of the epidermal growth factor receptor and other members of the ErbB family of receptor tyrosine kinases. It exerts its antitumor activity by a dual mechanism: via inhibition of these key receptors through their physical downregulation coupled with attenuation of their signaling, and by binding to and sequestering TGFbeta. Decorin also modulates the insulin-like growth factor receptor and the low-density lipoprotein receptor-related protein 1, which indirectly affects the TGFbeta receptor pathway. When expressed in tumor xenograft-bearing mice or injected systemically, decorin inhibits both primary tumor growth and metastatic spreading. In this review, we summarize the latest reports on decorin and related molecules that are relevant to cancer and bring forward the idea of decorin as an anticancer therapeutic and possible prognostic marker for patients affected by various types of tumors. We also discuss the role of lumican and LRIG1, a novel cell growth inhibitor homologous to decorin. (c) 2008 Wiley-Liss, Inc.

Opposite Role of Tumor Necrosis Factor Receptors in Dextran Sulfate Sodium-Induced Colitis in Mice

PubMed Central

Wang, Yi; Liu, Guijun; Wang, Renxi; Xiao, He; Li, Xinying; Hou, Chunmei; Shen, Beifen; Guo, Renfeng; Li, Yan; Shi, Yanchun; Chen, Guojiang

2012-01-01

Tumor necrosis factor-α (TNF-α) is a key factor for the pathogenesis of inflammatory bowel diseases (IBD), whose function is known to be mediated by TNF receptor 1 (TNFR1) or 2. However, the precise role of the two receptors in IBD remains poorly understood. Herein, acute colitis was induced by dextran sulfate sodium (DSS) instillation in TNFR1 or 2−/− mice. TNFR1 ablation led to exacerbation of signs of colitis, including more weight loss, increased mortality, colon shortening and oedema, severe intestinal damage, and higher levels of myeloperoxidase compared to wild-type counterparts. While, TNFR2 deficiency had opposite effects. This discrepancy was reflected by alteration of proinflammatory cytokine and chemokine production in the colons. Importantly, TNFR1 ablation rendered enhanced apoptosis of colonic epithelial cells and TNFR2 deficiency conferred pro-apoptotic effects of lamina propria (LP)-immune cells, as shown by the decreased ratio of Bcl-2/Bax and enhanced nuclear factor (NF)-κB activity. PMID:23285227

Differential regulation of insulin-like growth factor-I receptor gene expression by wild type and mutant androgen receptor in prostate cancer cells.

PubMed

Schayek, Hagit; Seti, Hila; Greenberg, Norman M; Sun, Shihua; Werner, Haim; Plymate, Stephen R

2010-07-29

The progression of prostate cancer from an organ-confined, androgen-sensitive disease to a metastatic one is associated with dysregulation of androgen receptor (AR)-regulated target genes and with a decrease in insulin-like growth factor-I receptor (IGF-IR) expression. To investigate the differential effects of wild type (wt) and mutant AR on IGF-IR levels we employed a series of isogenic prostate-derived cell lines and human xenografts. We show that basal and phosphorylated IGF-IR levels progressively decreased as prostate cancer cells became more tumorigenic and metastatic. In addition, we show that wt, but not mutant, AR along with dihydrotestosterone treatment increased IGF-IR promoter activity and endogenous IGF-IR levels. ChIP analysis show enhanced AR binding to the IGF-IR promoter in AR-overexpressing cells. Finally, wt AR-overexpressing cells display an enhanced proliferation rate. In summary, we provide evidence that activated wt AR enhances IGF-IR transcription in prostate cancer cells via a mechanism that involves AR binding to the IGF-IR promoter. AR mutations alter the ability of the mutated protein to regulate IGF-IR expression. Our results suggest that prostate cancer progression is associated with a decrease in IGF-IR expression that could be the result of impaired ability of AR to stimulate IGF-IR gene expression. 2010 Elsevier Ireland Ltd. All rights reserved.

Differential regulation of insulin-like growth factor-I receptor gene expression by wild type and mutant androgen receptor in prostate cancer cells

PubMed Central

Schayek, Hagit; Seti, Hila; Greenberg, Norman M.; Sun, Shihua; Werner, Haim; Plymate, Stephen R.

2010-01-01

The progression of prostate cancer from an organ-confined, androgen-sensitive disease to a metastatic one is associated with dysregulation of androgen receptor (AR)-regulated target genes and with a decrease in insulin-like growth factor-I receptor (IGF-IR) expression. To investigate the differential effects of wild type (wt) and mutant AR on IGF-IR levels we employed a series of isogenic prostate-derived cell lines and human xenografts. We show that basal and phosphorylated IGF-IR levels progressively decreased as prostate cancer cells became more tumorigenic and metastatic. In addition, we show that wt, but not mutant, AR along with dihydrotestosterone treatment increased IGF-IR promoter activity and endogenous IGF-IR levels. ChIP analysis show enhanced AR binding to the IGF-IR promoter in AR-overexpressing cells. Finally, wt AR-overexpressing cells display an enhanced proliferation rate. In summary, we provide evidence that activated wt AR enhances IGF-IR transcription in prostate cancer cells via a mechanism that involves AR binding to the IGF-IR promoter. AR mutations alter the ability of the mutated protein to regulate IGF-IR expression. Our results suggest that prostate cancer progression is associated with a decrease in IGF-IR expression that could be the result of impaired ability of AR to stimulate IGF-IR gene expression. PMID:20417685

Lenalidomide enhances the function of chimeric antigen receptor T cells against the epidermal growth factor receptor variant III by enhancing immune synapses.

PubMed

Kuramitsu, S; Ohno, M; Ohka, F; Shiina, S; Yamamichi, A; Kato, A; Tanahashi, K; Motomura, K; Kondo, G; Kurimoto, M; Senga, T; Wakabayashi, T; Natsume, A

2015-10-01

The epidermal growth factor receptor variant III (EGFRvIII) is exclusively expressed on the cell surface in ~50% of glioblastoma multiforme (GBM). This variant strongly and persistently activates the phosphatidylinositol 3-kinase-Akt signaling pathway in a ligand-independent manner resulting in enhanced tumorigenicity, cellular motility and resistance to chemoradiotherapy. Our group generated a recombinant single-chain variable fragment (scFv) antibody specific to the EGFRvIII, referred to as 3C10-scFv. In the current study, we constructed a lentiviral vector transducing the chimeric antigen receptor (CAR) that consisted of 3C10-scFv, CD3ζ, CD28 and 4-1BB (3C10-CAR). The 3C10-CAR-transduced peripheral blood mononuclear cells (PBMCs) and CD3(+) T cells specifically lysed the glioma cells that express EGFRvIII. Moreover, we demonstrated that CAR CD3(+) T cells migrated to the intracranial xenograft of GBM in the mice treated with 3C10-CAR PBMCs. An important and novel finding of our study was that a thalidomide derivative lenalidomide induced 3C10-CAR PBMC proliferation and enhanced the persistent antitumor effect of the cells in vivo. Lenalidomide also exhibited enhanced immunological synapses between the effector cells and the target cells as determined by CD11a and F-actin polymerization. Collectively, lentiviral-mediated transduction of CAR effectors targeting the EGFRvIII showed specific efficacy, and lenalidomide even intensified CAR cell therapy by enhanced formation of immunological synapses.

Imbalance of tumor necrosis factor receptors during progression in bovine leukemia virus infection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Konnai, Satoru; Usui, Tatsufumi; Ikeda, Manabu

2005-09-01

Previously, we found an up-regulation of tumor necrosis factor alpha (TNF)-{alpha} and an imbalance of TNF receptors in sheep experimentally infected with bovine leukemia virus (BLV). In order to investigate the different TNF-{alpha}-induced responses, in this study we examined the TNF-{alpha}-induced proliferative response and the expression levels of two distinct TNF receptors on peripheral blood mononuclear cells (PBMC) derived from BLV-uninfected cattle and BLV-infected cattle that were aleukemic (AL) or had persistent lymphocytosis (PL). The proliferative response of PBMC isolated from those cattle with PL in the presence of recombinant bovine TNF-{alpha} (rTNF-{alpha}) was significantly higher than those from ALmore » cattle and uninfected cattle and the cells from PL cattle expressed significantly higher mRNA levels of TNF receptor type II (TNF-RII) than those from AL and BLV-uninfected cattle. No difference was found in TNF-RI mRNA levels. Most cells expressing TNF-RII in PL cattle were CD5{sup +} or sIgM{sup +} cells and these cells showed resistance to TNF-{alpha}-induced apoptosis. Additionally, there were significant positive correlations between the changes in provirus load and TNF-RII mRNA levels, and TNF-{alpha}-induced proliferation and TNF-RII mRNA levels. These data suggest that imbalance in the expression of TNF receptors could at least in part contribute to the progression of lymphocytosis in BLV infection.« less

Amadori products promote cellular senescence activating insulin-like growth factor-1 receptor and down-regulating the antioxidant enzyme catalase.

PubMed

Del Nogal-Ávila, María; Troyano-Suárez, Nuria; Román-García, Pablo; Cannata-Andía, Jorge B; Rodriguez-Puyol, Manuel; Rodriguez-Puyol, Diego; Kuro-O, Makoto; Ruiz-Torres, María P

2013-07-01

Activation of the insulin growth factor receptor-1 signaling pathways has been largely related to the aging process. Amadori products are produced in pathological conditions such as diabetes and aging, and are potentially involved in diabetic nephropathy or age-associated decline of renal function. We hypothesize that Amadori products induce senescence in primary human mesangial cells through the activation of IGF-1 receptor and investigate, in the present work, the intracellular mechanism involved after this activation. We treated cultured human mesangial cells with glycated albumin, one of the most abundant Amadori product, and senescence was assessed by determining the senescence associated β-galactosidase activity and the expression of the cell cycle regulators p53 and p21. We demonstrated that prolonged exposition (more than 24h) to glycated albumin induced senescence and, in parallel, incremented the release of IGF-1 and the activation of the IGF-1 receptor. Inhibition of the IGF-1 activation prevented the GA induced senescence. Activation of IGF-1R, after GA addition, promoted a reduction in the catalase content through the constitutive activation of Ras and erk1/2 proteins which were, in turn, responsible of the observed GA-induced senescence. In conclusion, we propose that the Amadori product, glycated albumin, promotes premature cell senescence in mesangial cells through the activation of the IGF-1 receptor and the subsequent reduction in the antioxidant enzyme catalase. Copyright © 2013 Elsevier Ltd. All rights reserved.

A chimeric antigen receptor for TRAIL-receptor 1 induces apoptosis in various types of tumor cells.

PubMed

Kobayashi, Eiji; Kishi, Hiroyuki; Ozawa, Tatsuhiko; Hamana, Hiroshi; Nakagawa, Hidetoshi; Jin, Aishun; Lin, Zhezhu; Muraguchi, Atsushi

2014-10-31

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and its associated receptors (TRAIL-R/TR) are attractive targets for cancer therapy because TRAIL induces apoptosis in tumor cells through TR while having little cytotoxicity on normal cells. Therefore, many agonistic monoclonal antibodies (mAbs) specific for TR have been produced, and these induce apoptosis in multiple tumor cell types. However, some TR-expressing tumor cells are resistant to TR-specific mAb-induced apoptosis. In this study, we constructed a chimeric antigen receptor (CAR) of a TRAIL-receptor 1 (TR1)-specific single chain variable fragment (scFv) antibody (TR1-scFv-CAR) and expressed it on a Jurkat T cell line, the KHYG-1 NK cell line, and human peripheral blood lymphocytes (PBLs). We found that the TR1-scFv-CAR-expressing Jurkat cells killed target cells via TR1-mediated apoptosis, whereas TR1-scFv-CAR-expressing KHYG-1 cells and PBLs killed target cells not only via TR1-mediated apoptosis but also via CAR signal-induced cytolysis, resulting in cytotoxicity on a broader range if target cells than with TR1-scFv-CAR-expressing Jurkat cells. The results suggest that TR1-scFv-CAR could be a new candidate for cancer gene therapy. Copyright © 2014 Elsevier Inc. All rights reserved.

Identification of embryonic precursor cells that differentiate into thymic epithelial cells expressing autoimmune regulator

PubMed Central

Takizawa, Nobukazu; Miyauchi, Maki; Yanai, Hiromi; Tateishi, Ryosuke; Shinzawa, Miho; Yoshinaga, Riko; Kurihara, Masaaki; Yasuda, Hisataka; Sakamoto, Reiko; Yoshida, Nobuaki

2016-01-01

Medullary thymic epithelial cells (mTECs) expressing autoimmune regulator (Aire) are critical for preventing the onset of autoimmunity. However, the differentiation program of Aire-expressing mTECs (Aire+ mTECs) is unclear. Here, we describe novel embryonic precursors of Aire+ mTECs. We found the candidate precursors of Aire+ mTECs (pMECs) by monitoring the expression of receptor activator of nuclear factor-κB (RANK), which is required for Aire+ mTEC differentiation. pMECs unexpectedly expressed cortical TEC molecules in addition to the mTEC markers UEA-1 ligand and RANK and differentiated into mTECs in reaggregation thymic organ culture. Introduction of pMECs in the embryonic thymus permitted long-term maintenance of Aire+ mTECs and efficiently suppressed the onset of autoimmunity induced by Aire+ mTEC deficiency. Mechanistically, pMECs differentiated into Aire+ mTECs by tumor necrosis factor receptor-associated factor 6-dependent RANK signaling. Moreover, nonclassical nuclear factor-κB activation triggered by RANK and lymphotoxin-β receptor signaling promoted pMEC induction from progenitors exhibiting lower RANK expression and higher CD24 expression. Thus, our findings identified two novel stages in the differentiation program of Aire+ mTECs. PMID:27401343

Adoptive Cell Therapy for Metastatic Melanoma.

PubMed

Merhavi-Shoham, Efrat; Itzhaki, Orit; Markel, Gal; Schachter, Jacob; Besser, Michal J

Adoptive cell therapy (ACT) of tumor-infiltrating lymphocytes (TILs) is a powerful form of immunotherapy by inducing durable complete responses that significantly extend the survival of melanoma patients. Mutation-derived neoantigens were recently identified as key factors for tumor recognition and rejection by TILs. The isolation of T-cell receptor (TCR) genes directed against neoantigens and their retransduction into peripheral T cells may provide a new form of ACT.Genetic modifications of T cells with chimeric antigen receptors (CARs) have demonstrated remarkable clinical results in hematologic malignancies, but are so far less effective in solid tumors. Only very limited reports exist in melanoma. Progress in CAR T-cell engineering, including neutralization of inhibitory signals or additional safety switches, may open opportunities also in melanoma.We review clinical results and latest developments of adoptive therapies with TILs, T-cell receptor, and CAR-modified T cells and discuss future directions for the treatment of melanoma.

The TIM and TAM families of phosphatidylserine receptors mediate dengue virus entry.

PubMed

Meertens, Laurent; Carnec, Xavier; Lecoin, Manuel Perera; Ramdasi, Rasika; Guivel-Benhassine, Florence; Lew, Erin; Lemke, Greg; Schwartz, Olivier; Amara, Ali

2012-10-18

Dengue viruses (DVs) are responsible for the most medically relevant arboviral diseases. However, the molecular interactions mediating DV entry are poorly understood. We determined that TIM and TAM proteins, two receptor families that mediate the phosphatidylserine (PtdSer)-dependent phagocytic removal of apoptotic cells, serve as DV entry factors. Cells poorly susceptible to DV are robustly infected after ectopic expression of TIM or TAM receptors. Conversely, DV infection of susceptible cells is inhibited by anti-TIM or anti-TAM antibodies or knockdown of TIM and TAM expression. TIM receptors facilitate DV entry by directly interacting with virion-associated PtdSer. TAM-mediated infection relies on indirect DV recognition, in which the TAM ligand Gas6 acts as a bridging molecule by binding to PtdSer within the virion. This dual mode of virus recognition by TIM and TAM receptors reveals how DVs usurp the apoptotic cell clearance pathway for infectious entry. Copyright © 2012 Elsevier Inc. All rights reserved.

Endocytic function is critical for influenza A virus infection via DC-SIGN and L-SIGN

PubMed Central

Gillespie, Leah; Roosendahl, Paula; Ng, Wy Ching; Brooks, Andrew G.; Reading, Patrick C.; Londrigan, Sarah L.

2016-01-01

The ubiquitous presence of cell-surface sialic acid (SIA) has complicated efforts to identify specific transmembrane glycoproteins that function as bone fide entry receptors for influenza A virus (IAV) infection. The C-type lectin receptors (CLRs) DC-SIGN (CD209) and L-SIGN (CD209L) enhance IAV infection however it is not known if they act as attachment factors, passing virions to other unknown receptors for virus entry, or as authentic entry receptors for CLR-mediated virus uptake and infection. Sialic acid-deficient Lec2 Chinese Hamster Ovary (CHO) cell lines were resistant to IAV infection whereas expression of DC-SIGN/L-SIGN restored susceptibility of Lec2 cells to pH- and dynamin-dependent infection. Moreover, Lec2 cells expressing endocytosis-defective DC-SIGN/L-SIGN retained capacity to bind IAV but showed reduced susceptibility to infection. These studies confirm that DC-SIGN and L-SIGN are authentic endocytic receptors for IAV entry and infection. PMID:26763587

Role of tumour necrosis factor receptor-1 and nuclear factor-κB in production of TNF-α-induced pro-inflammatory microparticles in endothelial cells.

PubMed

Lee, S K; Yang, S-H; Kwon, I; Lee, O-H; Heo, J H

2014-09-02

Tumour necrosis factor-α (TNF-α) is upregulated in many inflammatory diseases and is also a potent agent for microparticle (MP) generation. Here, we describe an essential role of TNF-α in the production of endothelial cell-derived microparticles (EMPs) in vivo and the function of TNF-α-induced EMPs in endothelial cells. We found that TNF-α rapidly increased blood levels of EMPs in mice. Treatment of human umbilical vein endothelial cells (HUVECs) with TNF-α also induced EMP formation in a time-dependent manner. Silencing of TNF receptor (TNFR)-1 or inhibition of the nuclear factor-κB (NF-κB) in HUVECs impaired the production of TNF-α-induced EMP. Incubation of HUVECs with PKH-67-stained EMPs showed that endothelial cells readily engulfed EMPs, and the engulfed TNF-α-induced EMPs promoted the expression of pro-apoptotic molecules and upregulated intercellular adhesion molecule-1 level on the cell surface, which led to monocyte adhesion. Collectively, our findings indicate that the generation of TNF-α-induced EMPs was mediated by TNFR1 or NF-κB and that EMPs can contribute to apoptosis and inflammation of endothelial cells.