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Src
Kinds of Src Terms modified by Src Selected AbstractsOestradiol and SERM treatments influence oestrogen receptor coregulator gene expression in human skeletal muscle cellsACTA PHYSIOLOGICA, Issue 3 2009C. M. Dieli-Conwright Abstract Aim:, Oestrogen receptors (ER) are present in human skeletal muscle (hSkM) cells; however, the function of the receptor is currently unknown. We investigated the influence of oestradiol and selective ER modulators [tamoxifen (TAM), raloxifene (RAL)] on ER coregulator mRNA expression in hSkM. Methods:, Human skeletal muscle cells were treated with 10 nm oestradiol, 5 ,m TAM and 10 ,m RAL over a 24-h period. Following the treatment period, mRNA expression was quantified using real-time PCR to detect changes in ER-,, ER-,, steroid receptor coactivator (SRC), silencing mediator for retinoid and thyroid hormone receptors (SMRT), MyoD, GLUT4 and c-fos. Results:, ER-, mRNA expression increased with all three drug treatments (P < 0.05) while there was no change in mRNA expression of ER-, in hSkM cells. mRNA expression of SRC increased and SMRT decreased with oestradiol, TAM and RAL in hSkM cells (P < 0.05). Importantly, mRNA expression of MyoD increased with oestradiol and decreased with TAM and RAL in hSkM cells (P < 0.05). mRNA expression of GLUT4 increased with oestradiol and RAL and decreased with TAM in hSkM cells (P < 0.05). Conclusions:, These findings are novel in that they provide the first evidence that oestradiol and selective ER modulators influence ER-, function in hSkM cells. This demonstrates the importance of the ER and alterations in its coregulators, to potentially prevent sarcopenia and promote muscle growth in postmenopausal women using these forms of hormone replacement therapy. [source] Improving substance abuse treatment enrollment in community syringe exchangersADDICTION, Issue 5 2009Michael Kidorf ABSTRACT Aims The present study evaluated the effectiveness of an intervention combining motivational enhancement and treatment readiness groups, with and without monetary incentives for attendance and treatment enrollment, on enhancing rates of substance abuse treatment entry among new registrants at the Baltimore Needle Exchange Program (BNEP). Design Opioid-dependent study participants (n = 281) referred by the BNEP were assigned randomly to one of three referral interventions: (i) eight individual motivational enhancement sessions and 16 treatment readiness group sessions (motivated referral condition,MRC); (ii) the MRC intervention with monetary incentives for attending sessions and enrolling in treatment,MRC+I); or (iii) a standard referral condition which directed participants back to the BNEP for referral (standard referral,SRC). Participants were followed for 4 months. Findings MRC+I participants were more likely to enroll in any type of treatment than MRC or SRC participants (52.1% versus 31.9% versus 35.5%; ,2 = 9.12, P = 0.01), and more likely to enroll in treatment including methadone than MRC or SRC participants (40.4% versus 20.2% versus 16.1%; ,2 = 16.65, P < 0.001). MRC+I participants also reported less heroin and injection use than MRC and SRC participants. Conclusions Syringe exchange sites can be effective platforms to motivate opioid users to enroll in substance abuse treatment and ultimately reduce drug use and number of drug injections. [source] Performance comparison of square root raised-cosine and lerner filters for the MDFT-TMUX filter bankEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 6 2002A. Sudana Madhu Rao This paper deals with prototype filters, namely, square root raised , cosine (SRC) and Lerner filters in the modified discrete Fourier transform (MDFT) transmultiplexer (TMUX) filter bank. The error obtained in the reconstruction of the original signal is compared for various filter orders. These filters can be employed in multicarrier modulation system- overlapped discrete multitone (overlapped DMT) or discrete wavelet multitone (DWMT) system. However, with the SRC filter, a large number of computations are required. By employing Lerner filter, we can reduce this by atleast 3- folds. We have carried out simulation studies for an 8-channel MDFT- TMUX filter bank and the results obtained are presented. [source] Greenhouse gas emissions from four bioenergy crops in England and Wales: Integrating spatial estimates of yield and soil carbon balance in life cycle analysesGCB BIOENERGY, Issue 4 2009JONATHAN HILLIER Abstract Accurate estimation of the greenhouse gas (GHG) mitigation potential of bioenergy crops requires the integration of a significant component of spatially varying information. In particular, crop yield and soil carbon (C) stocks are variables which are generally soil type and climate dependent. Since gaseous emissions from soil C depend on current C stocks, which in turn are related to previous land management it is important to consider both previous and proposed future land use in any C accounting assessment. We have conducted a spatially explicit study for England and Wales, coupling empirical yield maps with the RothC soil C turnover model to simulate soil C dynamics. We estimate soil C changes under proposed planting of four bioenergy crops, Miscanthus (Miscanthus×giganteus), short rotation coppice (SRC) poplar (Populus trichocarpa Torr. & Gray ×P. trichocarpa, var. Trichobel), winter wheat, and oilseed rape. This is then related to the former land use , arable, pasture, or forest/seminatural, and the outputs are then assessed in the context of a life cycle analysis (LCA) for each crop. By offsetting emissions from management under the previous land use, and considering fossil fuel C displaced, the GHG balance is estimated for each of the 12 land use change transitions associated with replacing arable, grassland, or forest/seminatural land, with each of the four bioenergy crops. Miscanthus and SRC are likely to have a mostly beneficial impact in reducing GHG emissions, while oilseed rape and winter wheat have either a net GHG cost, or only a marginal benefit. Previous land use is important and can make the difference between the bioenergy crop being beneficial or worse than the existing land use in terms of GHG balance. [source] The persistence of bifidobacteria populations in a river measured by molecular and culture techniquesJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2009X. Bonjoch Abstract Aims:, To determine relative to faecal coliforms (FC) and sulfite-reducing clostridia (SRC), the environmental persistence of natural populations of Bifidobacterium spp. enumerated by culturing and quantitative polymerase chain reaction (q-PCR). Methods and Results:, Dialysis tubing containing river supplemented with overnight cultures of Bifidobacterium adolescentis (BA) and Bifidobacterium dentium (BD) or urban wastewater were suspended in a river for up to 10 days. At intervals, the contents of each dialysis tube were assayed using q-PCR assays for BA and BD, and selective culture media for FC, SRC, total bifidobacteria (TB), sorbitol-fermenting bifidobacteria (SFB) and cultivable BA. Mean summer T90 values were 251 h for SRC, 92 h for FC, 48 h for BA and BD by q-PCR, and 9 h for TB. Conclusions:,Bifidobacterium spp. was the population with the lowest persistence, showing seasonal differences in T90 when measured by culture techniques or by q-PCR. This difference in relative persistence is because of a longer persistence of molecular targets than cultivable cells. Significance and Impact of the Study:, The persistence of a viable bifidobacteria cells is shorter, but the longest persistence of molecular targets. This factor could be used for origin the faecal pollution in water for the development of microbial source tracking (MST). [source] Integration of colour and textural information in multivariate image analysis: defect detection and classification issuesJOURNAL OF CHEMOMETRICS, Issue 1-2 2007J. M. Prats-Montalbán Abstract In industrial processes, the detection and visualisation of defects and the development of efficient automated classification tools are strategic issues, especially when dealing with random colour textures (RCTs). This paper discusses the benefits of integrating colour and spatial (i.e. textural) information of digital RGB colour images in multivariate image analysis (MIA) to deal with these topics. Regarding the first one, a simple and computational cost-effective monitoring procedure based on colour-textural MIA merged with multivariate statistical process control (MSPC) ideas is outlined. Two novel computed images: T2 and RSS Images are proposed. The procedure is applied on digital RGB colour images from artificial stone plates. With respect to the second issue, when colour-textural MIA is used for image classification a lot of factors (e.g. pre-processing, modelling,,,) likely affecting the success rate in the classification (SRC) show up. This paper presents a methodology based on the combination of experimental design and logistic regression for choosing the best combination of factors to maximise the SRC of different types of images. Digital RGB colour images from ceramic tiles and orange fruits are used to illustrate the potential of the proposed methodology. Copyright © 2007 John Wiley & Sons, Ltd. [source] CHARACTERIZATION OF FOOD SURFACES USING SCALE-SENSITIVE FRACTAL ANALYSISJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2000FRANCO PEDRESCHI ABSTRACT Length-scale and area-scale analyses, two of the scale-sensitive fractal analyses performed by the software Surfraxhttp://www.surfract.com, were used to study food surfaces measured with a scanning laser microscope (SLM). The SLM measures surfaces, or textures (i.e., acquires topographical data as a collection of heights as a function of position), at a spatial and vertical resolution of 25 ,m. The measured textures are analyzed by using linear and areal tiling (length-scale and area-scale analysis) and by conventional statistical analyses. Area-scale and length-scale fractal complexities (Lsfc and Asfc) and the smooth-rough crossover (SRC) are derived from the scale-sensitive fractal analyses. Both measures proved adequate to quantify and differentiate surfaces of foods (e.g., chocolate and a slice of bread), which were smooth or porous to the naked eye. Surfaces generated after frying of potato products (e.g., potato chips and French fries) had similar values of Asfc and SRC, and larger (implying more complex and rougher surfaces) than those of the raw potato. Variability of surface texture characterization parameters as a function of the size of the measured region was used in selecting the size of the measured regions for further analysis. The length-scale method of profile analysis (also called the Richardson or compass method) was useful in determining the directionality or lay of the anisotropic texture on food surfaces. [source] First results from the Canadian SGM beamline at SRCJOURNAL OF SYNCHROTRON RADIATION, Issue 5 2000B. W. Yates The first experimental results obtained from the Canadian SGM beamline at SRC (Synchrotron Radiation Centre, University of Wisconsin-Madison, USA) are reported. The beamline is based on the Dragon-type design, with a constant deviation angle, using photons from a second-generation bending-magnet light source. The medium-energy grating on this beamline covers a photon energy range from 240 to 700,eV, with a ruling density of 600,lines,mm,1. A maximum resolving power of ,10000 is achieved at a photon energy of ,400,eV. Gas-phase absorption spectra collected at the N, O and C K -edges are presented to demonstrate the excellent performance of this beamline. High-resolution absorption spectra of some C- and Ti-containing solid-state samples are also reported. [source] Half-metallic ferromagnetism in wurtzite SrCPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 1 2008Chang-wen Zhang Abstract The first-principles full potential linearized augmented plane-wave method within density-functional theory is used to investigate electronic structure and magnetism of wurtzite (WZ) crystal structure SrC. It is shown that the WZ SrC is a true half-metallic ferromagnet with a magnetic moment of 2,B per formula unit. The large HM gaps (0.72 eV) and robustness of half-metallicity with respect to the lattice change make it possible candidate grown epitaxially on appropriate substrates in the form of films thick enough, and therefore should be useful in spintronics and other related applications. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A FAK/Src chimera with gain-of-function properties promotes formation of large peripheral adhesions associated with dynamic actin assemblyCYTOSKELETON, Issue 1 2008Priscila M. F. Siesser Abstract Formation of a complex between the tyrosine kinases FAK and Src is a key integrin-mediated signaling event implicated in cell motility, survival, and proliferation. Past studies indicate that FAK functions in the complex primarily as a "scaffold," acting to recruit and activate Src within cell/matrix adhesions. To study the cellular impact of FAK-associated Src signaling we developed a novel gain-of-function approach that involves expressing a chimeric protein with the FAK kinase domain replaced by the Src kinase domain. This FAK/Src chimera is subject to adhesion-dependent activation and promotes tyrosine phosphorylation of p130Cas and paxillin to higher steady-state levels than is achieved by wild-type FAK. When expressed in FAK ,/, mouse embryo fibroblasts, the FAK/Src chimera resulted in a striking cellular phenotype characterized by unusual large peripheral adhesions, enhanced adhesive strength, and greatly reduced motility. Live cell imaging of the chimera-expressing FAK ,/, cells provided evidence that the large peripheral adhesions are associated with a dynamic actin assembly process that is sensitive to a Src-selective inhibitor. These findings suggest that FAK-associated Src kinase activity has the capacity to promote adhesion integrity and actin assembly. Cell Motil. Cytoskeleton 2008. © 2007 Wiley-Liss, Inc. [source] Src-dependent phosphorylation of Scar1 promotes its association with the Arp2/3 complexCYTOSKELETON, Issue 1 2006Hazel Ardern Abstract The WAVE/Scar proteins regulate actin polymerisation at the leading edge of motile cells via activation of the Arp2/3 complex in response to extracellular cues. Within cells they form part of a pentameric complex that is thought to regulate their ability to interact and activate the Arp2/3 complex. However, the exact mechanism for this is not known. We set out to assess whether phosphorylation of Scar1 by the non-receptor tyrosine kinase Src may influence the function of Scar1 and its ability to regulate Arp2/3-mediated actin polymerisation. We show that Scar1 is phosphorylated by Src in vitro and in vivo and identify tyrosine 125 as the major site in Scar1 to be phosphorylated in cells. Src-dependent phosphorylation of Scar1 on tyrosine 125 enhances its ability to bind to the Arp2/3 complex and regulates its ability to control actin polymerisation in cells. Thus, Src may act as an intermediary to regulate the activity of the Arp2/3 complex in response to external stimuli, via modulation of its interaction with WAVE/Scar proteins. Cell Motil. Cytoskeleton, 2006. © 2005 Wiley-Liss, Inc. [source] LAR protein tyrosine phosphatase receptor associates with TrkB and modulates neurotrophic signaling pathwaysDEVELOPMENTAL NEUROBIOLOGY, Issue 13 2006Tao Yang Abstract The identities of receptor protein tyrosine phosphatases (PTPs) that associate with Trk protein tyrosine kinase (PTK) receptors and modulate neurotrophic signaling are unknown. The leukocyte common antigen-related (LAR) receptor PTP is present in neurons expressing TrkB, and like TrkB is associated with caveolae and regulates survival and neurite outgrowth. We tested the hypothesis that LAR associates with TrkB and regulates neurotrophic signaling in embryonic hippocampal neurons. Coimmunoprecipitation and coimmunostaining demonstrated LAR interaction with TrkB that is increased by BDNF exposure. BDNF neurotrophic activity was reduced in LAR,/, and LAR siRNA-treated LAR+/+ neurons and was augmented in LAR-transfected neurons. In LAR,/, neurons, BDNF-induced activation of TrkB, Shc, AKT, ERK, and CREB was significantly decreased; while in LAR-transfected neurons, BDNF-induced CREB activation was augmented. Similarly, LAR+/+ neurons treated with LAR siRNA demonstrated decreased activation of Trk and AKT. LAR is known to activate the Src PTK by dephosphorylation of its negative regulatory domain and Src transactivates Trk. In LAR,/, neurons, or neurons treated with LAR siRNA, phosphorylation of the Src regulatory domain was increased (indicating Src inactivation), consistent with a role for Src in mediating LAR's ability to up-regulate neurotrophic signaling. Interactions between LAR, TrkB, and Src were further confirmed by the findings that Src coimmunoprecipitated with LAR, that the Src inhibitor PP2 blocked the ability of LAR to augment TrkB signaling, and that siRNA-induced depletion of Src decreased LAR interaction with TrkB. These studies demonstrate that receptor PTPs can associate with Trk complexes and promote neurotrophic signaling and point to receptor PTP-based strategies as a novel approach for modulating neurotrophin function. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source] Contribution of the Reelin signaling pathways to nociceptive processingEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2008Alin L. Akopians Abstract The reeler gene encodes Reelin, a secreted glycoprotein that binds to the very-low-density lipoprotein receptor (Vldlr) and apolipoprotein E receptor 2 (Apoer,2), and induces Src- and Fyn-mediated tyrosine phosphorylation of the intracellular adaptor protein Disabled-1 (Dab1). This Reelin,Dab1 signaling pathway regulates neuronal positioning during development. A second Reelin pathway acts through Apoer,2,exon 19 to modulate synaptic plasticity in adult mice. We recently reported positioning errors in reeler dorsal horn laminae I,II and V, and the lateral spinal nucleus. Behavioral correlates of these positioning errors include a decreased mechanical and increased thermal sensitivity in reeler mice. Here we examined mice with deletions or modifications of both the Reelin,Dab1 signaling pathway and the Reelin,Apoer,2,exon 19 pathway on a Vldlr-deficient background. We detected reeler -like dorsal horn positioning errors only in Dab1 mutant and Apoer,2/Vldlr double mutant mice. Although Dab1 mutants, like reeler, showed decreased mechanical and increased thermal sensitivity, neither the single Vldlr or Apoer,2 knockouts, nor the Apoer,2,exon 19 mutants differed in their acute pain sensitivity from controls. However, despite the dramatic alterations in acute ,pain' processing in reeler and Dab1 mutants, the exacerbation of pain processing after tissue injury (hindpaw carrageenan injection) was preserved. Finally, we recapitulated the reeler dorsal horn positioning errors by inhibiting Dab1 phosphorylation in organotypic cultures. We conclude that the Reelin,Dab1 pathway differentially contributes to acute and persistent pain, and that the plasticity associated with the Reelin,Apoer,2,exon 19 pathway is distinct from that which contributes to injury-induced enhancement of ,pain' processing. [source] Identification and functional characterization of an Src homology domain 3 domain-binding site on CblFEBS JOURNAL, Issue 23 2006Archana Sanjay§ Cbl is an adaptor protein and ubiquitin ligase that binds and is phosphorylated by the nonreceptor tyrosine kinase Src. We previously showed that the primary interaction between Src and Cbl is mediated by the Src homology domain 3 (SH3) of Src binding to proline-rich sequences of Cbl. The peptide Cbl RDLPPPPPPDRP(540,551), which corresponds to residues 540,551 of Cbl, inhibited the binding of a GST,Src SH3 fusion protein to Cbl, whereas RDLAPPAPPPDR(540,551) did not, suggesting that Src binds to this site on Cbl in a class I orientation. Mutating prolines 543,548 reduced Src binding to the Cbl 479,636 fragment significantly more than mutating the prolines in the PPVPPR(494,499) motif, which was previously reported to bind Src SH3. Mutating Cbl prolines 543,548 to alanines substantially reduced Src binding to Cbl, Src-induced phosphorylation of Cbl, and the inhibition of Src kinase activity by Cbl. Expressing the mutated Cbl in osteoclasts induced a moderate reduction in bone-resorbing activity and increased amounts of Src protein. In contrast, disabling the tyrosine kinase-binding domain of full-length Cbl by mutating glycine 306 to glutamic acid, and thereby preventing the previously described binding of the tyrosine kinase-binding domain to the Src phosphotyrosine 416, had no effect on Cbl phosphorylation, the inhibition of Src activity by full-length Cbl, or bone resorption. These data indicate that the Cbl RDLPPPP(540,546) sequence is a functionally important binding site for Src. [source] Palmitoylation-dependent endosomal localization of AATYK1A and its interaction with SrcGENES TO CELLS, Issue 9 2008Koji Tsutsumi Apoptosis-associated tyrosine kinase 1 (AATYK1), also named LMTK1, was previously isolated as an apoptosis-related gene from 32Dcl3 myeloid precursor cells, but its precise function remains unknown. AATYK1A, an isoform without a transmembrane domain, is highly expressed in neurons. We identified palmitoylation of AATYK1A at three N-terminal cysteine residues in cortical cultured neurons and COS-7 cells and found that palmitoylation determined localization of AATYK1A to the transferrin receptor-positive recycling endosomes. Further, we identified the tyrosine kinase Src as a novel AATYK1A-interacting protein. Src and Fyn phosphorylated AATYK1A at tyrosines 25 and 46 in a palmitoylation-dependent manner. The association of AATYK1A with Src in endosomes was also found to be palmitoylation-dependent. These results indicate that palmitoylation is a critical factor not only for the subcellular localization of AATYK1A but also for its interaction with Src. [source] Characterization of Xenopus egg membrane microdomains containing uroplakin Ib/III complex: roles of their molecular interactions for subcellular localization and signal transductionGENES TO CELLS, Issue 2 2007A.K.M. Mahbub Hasan A single-transmembrane protein uroplakin III (UPIII) and its tetraspanin binding-partner uroplakin Ib (UPIb) are members of the UP proteins that were originally identified in mammalian urothelium. In Xenopus laevis eggs, these proteins: xUPIII and xUPIb, are components of the cholesterol-enriched membrane microdomains or "rafts" and involved in the sperm,egg membrane interaction and subsequent egg activation signaling via Src tyrosine kinase at fertilization. Here, we investigate whether the xUPIII-xUPIb complex is in close proximity to CD9, a tetraspanin that has been implicated in the sperm,egg fusion in the mouse and GM1, a ganglioside typically enriched in egg rafts. Preparation of the egg membrane microdomains using different non-ionic detergents (Brij 98 and Triton X-100), chemical cross-linking, co-immunoprecipitation, in vitro kinase assay and in vitro fertilization experiments demonstrated that GM1, but not CD9, is in association with the xUPIII-xUPIb complex and contributes to the sperm-dependent egg activation. Transfection experiments using HEK293 cells demonstrated that xUPIII and xUPIb localized efficiently to the cholesterol-dependent membrane microdomains when they were co-expressed, whereas co-expression of xUPIII and CD9, instead of xUPIb, did not show this effect. Furthermore, xUPIII and xUPIb were shown to suppress kinase activity of the wild type, but not a constitutively active form of, Xenopus Src protein co-expressed in HEK293 cells. These results provide novel insight into the molecular architecture of the egg membrane microdomains containing xUPIII, xUPIb and Src, which may contribute to the understanding of sperm,egg interaction and signaling during Xenopus fertilization. [source] The Versatility of Helicobacter pylori CagA Effector Protein Functions: The Master Key HypothesisHELICOBACTER, Issue 3 2010Steffen Backert Abstract Several bacterial pathogens inject virulence proteins into host target cells that are substrates of eukaryotic tyrosine kinases. One of the key examples is the Helicobacter pylori CagA effector protein which is translocated by a type-IV secretion system. Injected CagA becomes tyrosine-phosphorylated on EPIYA sequence motifs by Src and Abl family kinases. CagA then binds to and activates/inactivates multiple signaling proteins in a phosphorylation-dependent and phosphorylation-independent manner. A recent proteomic screen systematically identified eukaryotic binding partners of the EPIYA phosphorylation sites of CagA and similar sites in other bacterial effectors by high-resolution mass spectrometry. Individual phosphorylation sites recruited a surprisingly high number of interaction partners suggesting that each phosphorylation site can interfere with many downstream pathways. We now count 20 reported cellular binding partners of CagA, which represents the highest quantitiy among all yet known virulence-associated effector proteins in the microbial world. This complexity generates a highly remarkable and puzzling scenario. In addition, the first crystal structure of CagA provided us with new information on the function of this important virulence determinant. Here we review the recent advances in characterizing the multiple binding signaling activities of CagA. Injected CagA can act as a ,master key' that evolved the ability to highjack multiple host cell signalling cascades, which include the induction of membrane dynamics, actin-cytoskeletal rearrangements and the disruption of cell-to-cell junctions as well as proliferative, pro-inflammatory and anti-apoptotic nuclear responses. The discovery that different pathogens use this common strategy to subvert host cell functions suggests that more examples will emerge soon. [source] Radiation-induced HIF-1, cell survival pathway is inhibited by soy isoflavones in prostate cancer cellsINTERNATIONAL JOURNAL OF CANCER, Issue 7 2009Vinita Singh-Gupta Abstract We previously showed that treatment of prostate cancer cells with soy isoflavones and radiation resulted in greater cell killing in vitro, and caused downregulation of NF-,B and APE1/Ref-1. APE1/Ref-1 functions as a redox activator of transcription factors, including NF-,B and HIF-1,. These molecules are upregulated by radiation and implicated in radioresistance of cancer cells. We extended our studies to investigate the role of HIF-1, survival pathway and its upstream Src and STAT3 molecules in isoflavones and radiation interaction. Radiation induced phosphorylation of Src and STAT3 leading to induction of HIF-1,. Genistein, daidzein or a mixture of soy isoflavones did not activate this pathway. These data were observed both in PC-3 (AR-) and C4-2B (AR+) androgen-independent cell lines. Pretreatment with isoflavones inhibited Src/STAT3/HIF-1, activation by radiation and nuclear translocation of HIF-1,. These findings correlated with decreased expression of APE1/Ref-1 and DNA binding activity of HIF-1, and NF-,B. In APE1/Ref-1 cDNA transfected cells, radiation caused a greater increase in HIF-1, and NF-,B activities but this effect was inhibited by pretreatment with soy prior to radiation. Transfection experiments indicate that APE1/Ref-1 inhibition by isoflavones impairs the radiation-induced transcription activity of NF-,B and HIF-1,. This mechanism could result in the inhibition of genes essential for tumor growth and angiogenesis, as demonstrated by inhibition of VEGF production and HUVECs tube formation. Our novel findings suggest that the increased responsiveness to radiation mediated by soy isoflavones could be due to pleiotropic effects of isoflavones blocking cell survival pathways induced by radiation including Src/STAT3/HIF-1,, APE1/Ref-1 and NF-,B. © 2008 Wiley-Liss, Inc. [source] Nicotine induces cell proliferation, invasion and epithelial-mesenchymal transition in a variety of human cancer cell linesINTERNATIONAL JOURNAL OF CANCER, Issue 1 2009Piyali Dasgupta Abstract Cigarette smoking is strongly correlated with the onset of nonsmall cell lung cancer (NSCLC). Nicotine, an active component of cigarettes, has been found to induce proliferation of lung cancer cell lines. In addition, nicotine can induce angiogenesis and confer resistance to apoptosis. All these events are mediated through the nicotinic acetylcholine receptors (nAChRs) on lung cancer cells. In this study, we demonstrate that nicotine can promote anchorage-independent growth in NSCLCs. In addition, nicotine also induces morphological changes characteristic of a migratory, invasive phenotype in NSCLCs on collagen gel. These morphological changes were similar to those induced by the promigratory growth factor VEGF. The proinvasive effects of nicotine were mediated by ,7-nAChRs on NSCLCs. RT-PCR analysis showed that the ,7-nAChRs were also expressed on human breast cancer and pancreatic cancer cell lines. Nicotine was found to promote proliferation and invasion in human breast cancer. The proinvasive effects of nicotine were mediated via a nAChR, Src and calcium-dependent signaling pathway in breast cancer cells. In a similar fashion, nicotine could also induce proliferation and invasion of Aspc1 pancreatic cancer cells. Most importantly, nicotine could induce changes in gene expression consistent with epithelial to mesenchymal transition (EMT), characterized by reduction of epithelial markers like E-cadherin expression, ZO-1 staining and concomitant increase in levels of mesenchymal proteins like vimentin and fibronectin in human breast and lung cancer cells. Therefore, it is probable that the ability of nicotine to induce invasion and EMT may contribute to the progression of breast and lung cancers. © 2008 Wiley-Liss, Inc. [source] Integrin signaling through FAK in the regulation of mammary stem cells and breast cancerIUBMB LIFE, Issue 4 2010Jun-Lin Guan Abstract Focal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase identified as a key mediator of intracellular signaling by integrins, a major family of cell surface receptors for extracellular matrix, in the regulation of different cellular functions in a variety of cells. Upon activation by integrins through disruption of an autoinhibitory mechanism, FAK undergoes autophosphorylation and forms a complex with Src and other cellular proteins to trigger downstream signaling through its kinase activity or scaffolding function. A number of integrins are identified as surface markers for mammary stem cells (MaSCs), and both integrins and FAK are found to play crucial roles in the maintenance of MaSCs in studies using mouse models, suggesting that integrin signaling through FAK may serve as a functional marker for MaSCs. Consistent with previous studies linking increased expression and activation of FAK to human breast cancer, these findings suggest a novel cellular mechanism of FAK promotion of mammary tumorigenesis by maintaining the pools of MaSCs as targets of oncogenic transformation. Furthermore, FAK inactivation in mouse models of breast cancer also reduced the pool of mammary cancer stem cells (MaCSCs), decreased their self-renewal in vitro, and compromised their tumorigenicity and maintenance in vivo, suggesting a potential role of integrin signaling through FAK in breast cancer growth and progression through its functions in MaCSCs. This review discusses these recent advances and future studies into the mechanism of integrin signaling through FAK in breast cancer through regulation of MaCSCs that may lead to development of novel therapies for this deadly disease. © 2010 IUBMB IUBMB Life, 62(4): 268,276, 2010 [source] Novel indoloquinoline derivative, IQDMA, inhibits STAT5 signaling associated with apoptosis in K562 cellsJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 6 2008Sheng-Huei Yang Abstract N,-(11H-indolo[3,2-c]quinolin-6-yl)- N,N -dimethylethane-1,2-diamine (IQDMA), an indoloquinoline derivative, synthesized in our laboratory, has been demonstrated to be an effective antitumor agent in human leukemia cells. In the present study, treatment with IQDMA inhibited phosphorylation of epidermal growth factor receptor (EGFR), Src, Bcr-Abl, and Janus-activated kinase (JAK2) in a time-dependent manner. IQDMA also degraded JAK2 protein. Moreover, signal transducer and activator of transcription 5 (STAT5) signaling were also blocked by IQDMA. However, IQDMA did not inhibit other oncogenic and tumor survival pathways such as those mediated by Akt and extracellular signal-regulated kinase 1/2. Furthermore, IQDMA upregulated the expression of p21 and p27 and downregulated the expression of cyclin D1, myeloid cell leukemia-1(Mcl-1), Bcl-XL, and vascular endothelial growth factor (VEGF). Taken together, these results indicate that IQDMA causes significant induction of apoptosis in K562 cells via downregulation of EGFR, Src, Bcr-Abl, JAK2, and STAT5 signaling and modulation of p21, p27, cyclin D1, Mcl-1, Bcl-XL, and VEGF proteins. Thus, IQDMA appears to be a potential therapeutic agent for treating leukemia K562 cells. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:396,404, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20254 [source] Intracellular signaling involved in macrophage adhesion and FBGC formation as mediated by ligand,substrate interactionJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 4 2002Weiyuan John Kao Abstract Fibronectin and RGD- and/or PHSRN-containing oligopeptides were preadsorbed onto physicochemically distinct substrata: polyethyleneglycol-based networks or tissue culture polystyrene (TCPS). The role of selected signaling kinases (namely protein tyrosine kinases, protein serine/threonine kinases, PI3-kinase, Src, and MAPK) in the adhesion of human primary blood-derived macrophages and the formation of foreign-body giant cells (FBGC) on these modified substrata was investigated. The involvement of individual intracellular signaling molecules in mediating macrophage adhesion dynamically varied with the culture time, substrate, and ligand. For example, fibronectin on TCPS or networks involved similar signaling events for macrophage adhesion; however, fibronectin and G3RGDG6PHSRNG, but not peptides with other RGD and/or PHSRN orientations, mediated similar signaling events for macrophage adhesion on TCPS but mediated different signaling events on networks. Depending on the substrate, a specific molecule (i.e., Src, protein kinase C) within the protein tyrosine kinase or protein serine/threonine kinase family was either an antagonist or agonist in mediating FBGC formation. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 478,487, 2002 [source] Src promotes delta opioid receptor (DOR) desensitization by interfering with receptor recyclingJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 1 2009Elodie Archer-Lahlou Abstract An important limitation in the clinical use of opiates is progressive loss of analgesic efficacy over time. Development of analgesic tolerance is tightly linked to receptor desensitization. In the case of delta opioid receptors (DOR), desensitization is especially swift because receptors are rapidly internalized and are poorly recycled to the membrane. In the present study, we investigated whether Src activity contributed to this sorting pattern and to functional desensitization of DORs. A first series of experiments demonstrated that agonist binding activates Src and destabilizes a constitutive complex formed by the spontaneous association of DORs with the kinase. Src contribution to DOR desensitization was then established by showing that pre-treatment with Src inhibitor PP2 (20 ,M; 1 hr) or transfection of a dominant negative Src mutant preserved DOR signalling following sustained exposure to an agonist. This protection was afforded without interfering with endocytosis, but suboptimal internalization interfered with PP2 ability to preserve DOR signalling, suggesting a post-endocytic site of action for the kinase. This assumption was confirmed by demonstrating that Src inhibition by PP2 or its silencing by siRNA increased membrane recovery of internalized DORs and was further corroborated by showing that inhibition of recycling by monensin or dominant negative Rab11 (Rab11S25N) abolished the ability of Src blockers to prevent desensitization. Finally, Src inhibitors accelerated recovery of DOR-G,l3 coupling after desensitization. Taken together, these results indicate that Src dynamically regulates DOR recycling and by doing so contributes to desensitization of these receptors. [source] A novel intracellular isoform of VEGFR-1 activates Src and promotes cell invasion in MDA-MB-231 breast cancer cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2010Belén Mezquita Abstract Two types of VEGFR-1 receptors have been characterized: a full-length transmembrane receptor and a truncated extracellular soluble isoform (sVEGFR-1). We report here the characterization, in normal and cancer cells, of a new family of intracellular isoforms of VEGFR-1 resulting from alternative initiation of transcription in intronic sequences of the gene. While the classical isoforms of VEGFR-1 were barely detectable in MDA-MB-231 breast cancer cells, one of the intracellular isoforms transcribed from intron 21 (i21VEGFR-1) was the main isoform expressed in these cells. The new transcript encodes for a protein that contains only the phosphotransferase domain and the carboxyterminal tail of VEGFR-1. Treatment of MDA-MB-231 cells with siRNA specific for the tyrosine domain of VEGFR-1 suppressed the expression of i21VEGFR-1, downregulated phosphorylation of Src at tyrosine 418, and reduced markedly the invasion capacity of these cells in vitro. Accordingly, overexpression of transfected i21VEGFR-1 in MDA-MB-231 cells upregulated the active form of Src and increased invasiveness of MDA-MB-231 cells. The expression of i21VEGFR-1 in MDA-MB-231 cells was inhibited by retinoic acid. Both, activation of Src and downregulation by retinoic acid, have been reported in other intracellular members of the Fms/Kit/PDGFR family of tyrosine kinases, particularly in the intracellular isoform of c-kit, analogous structurally to i21VEGFR-1 and frequently expressed in cancer cells. J. Cell. Biochem. 110: 732,742, 2010. © 2010 Wiley-Liss, Inc. [source] Src and FAK mediate cell,matrix adhesion-dependent activation of met during transformation of breast epithelial cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2009Angela Y. Hui Abstract Cell,matrix adhesion has been shown to promote activation of the hepatocyte growth factor receptor, Met, in a ligand-independent manner. This process has been linked to transformation and tumorigenesis in a variety of cancer types. In the present report, we describe a key role of integrin signaling via the Src/FAK axis in the activation of Met in breast epithelial and carcinoma cells. Expression of an activated Src mutant in non-neoplastic breast epithelial cells or in carcinoma cells was found to increase phosphorylation of Met at regulatory tyrosines in the auto-activation loop domain, correlating with increased cell spreading and filopodia extensions. Furthermore, phosphorylated Met is complexed with ,1 integrins and is co-localized with vinculin and FAK at focal adhesions in epithelial cells expressing activated Src. Conversely, genetic or pharmacological inhibition of Src abrogates constitutive Met phosphorylation in carcinoma cells or epithelial cells expressing activated Src, and inhibits filopodia formation. Interestingly, Src-dependent phosphorylation of Met requires cell,matrix adhesion, as well as actin stress fiber assembly. Phosphorylation of FAK by Src is also required for Src-induced Met phosphorylation, emphasizing the importance of the Src/FAK signaling pathway. However, stimulation of Met phosphorylation by addition of exogenous HGF in epithelial cells is refractory to inhibition of Src family kinases, indicating that HGF-dependent and Src/integrin-dependent Met activation occur via distinct mechanisms. Together these findings demonstrate a novel mechanism by which the Src/FAK axis links signals from the integrin adhesion complex to promote Met activation in breast epithelial cells. J. Cell. Biochem. 107: 1168,1181, 2009. © 2009 Wiley-Liss, Inc. [source] ,1,3 fucosyltransferase-VII up-regulates the mRNA of ,5 integrin and its biological functionJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2008Qiu-yan Wang Abstract After transfection of ,1,3fucosyltransferase (FucT)-VII cDNA into H7721 human hepatocarcinoma cells, the expression of ,5, but not ,1 integrin was significantly up-regulated. This was evidenced by the increase of ,5 integrin on cell surface as well as the increase of ,5 mRNA and protein in the cells. However, the expressions of sialyl Lewis X (SLex, the product of ,1,3FucT-VII) on both ,5 and ,1 integrin subunits were unchanged. Concomitantly, the tyrosine autophosphorylated FAK and dephosphorylated Src (FAK and Src involve in the signal transduction of integrin ,5,1) were up-regulated, while the Tyr-527 phosphorylated Src was down-regulated. The above-mentioned alterations were correlated to the expressions of ,1,3FucT-VII in different ,1,3FucT-VII transfected H7721 cell lines. In addition, after ,1,3FucT-VII transfection, cell adhesion to fibronectin (Fn) and chemotaxic cell migration were obviously promoted. The cell adhesion could be blocked by ,5 integrin antibody, and cell migration was obviously attenuated by the antibodies to both ,5 integrin and SLex. These findings suggest that the increased surface ,5 integrin caused by the up-regulation of ,5 mRNA promotes the cell adhesion to Fn, cell migratiom, and Fn-induced signaling of ,5,1 integrin. The up-regulation of surface SLex originated from the over expression of ,1,3FucT-VII also led to the stimulation of cell migration. This is the first time to report that ,1,3FucT-VII can regulate the mRNA expression of integrin. J. Cell. Biochem. 104: 2078,2090, 2008. © 2008 Wiley-Liss, Inc. [source] Paxillin modulates squamous cancer cell adhesion and is important in pressure-augmented adhesionJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2006William C. Conway Abstract Paxillin is an adapter protein regulating signaling and focal adhesion assembly that has been linked to malignant potential in many malignancies. Overexpression of paxillin has been noted in aggressive tumors. Integrin-mediated binding through the focal adhesion complex is important in metastatic adhesion and is upregulated by extracellular pressure in malignant colonocytes through FAK and Src activation. Neither head and neck cancers nor paxillin have been studied in this regard. We hypothesized that paxillin would play a role in modulating squamous cancer adhesion both at baseline and under conditions of increased extracellular pressure. Using SCC25 tongue squamous cancer cells stably transfected with either an empty selection vector or paxillin expression and selection vectors, we studied adhesion to collagen, paxillin, FAK, and Src expression and phosphorylation in cells maintained for 30 min under ambient or 15 mmHg increased pressure conditions. Paxillin-overexpressing cells exhibited adhesion 121,±,2.9% of that observed in vector-only cells (n,=,6, P,<,0.001) under ambient pressure. Paxillin-overexpression reduced FAK phosphorylation. Pressure stimulated adhesion to 118,±,2.3% (n,=,6, P,<,0.001) of baseline in vector-only cells, similar to its effect in the parental line, and induced paxillin, FAK, and Src phosphorylation. However, increased pressure did not stimulate adhesion or phosphorylate paxillin, FAK, or Src further in paxillin-overexpressing cells. Metastasizing squamous cancer cell adhesiveness may be increased by paxillin-overexpression or by paxillin activation by extracellular pressure during surgical manipulation or growth within a constraining compartment. Targeting paxillin in patients with malignancy and minimal tumor manipulation during surgical resection may be important therapeutic adjuncts. J. Cell. Biochem. © 2006 Wiley-Liss, Inc. [source] Transforming growth factor-,1-dependent activation of Smad2/3 and up-regulation of PAI-1 expression is negatively regulated by Src in SKOV-3 human ovarian cancer cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2004Kiyoshi Wakahara Abstract The net balance between urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type-1 (PAI-1) has been implicated in tumor cell invasion and metastasis. To elucidate the mechanism of the transforming growth factor-,1 (TGF-,1)-dependent up-regulation of PAI-1 expression, we investigated which signaling pathway transduced by TGF-,1 is responsible for this effect. Here, we show (1) nontoxic concentrations of TGF-,1 up-regulates uPA expression in HRA and SKOV-3 human ovarian cancer cells, (2) TGF-,1 activates Smads (phosphorylation of Smad2 and nuclear translocation of Smad3) and subsequently up-regulates PAI-1 expression in HRA cells, whereas TGF-,1 neither activates Smads nor up-regulates PAI-1 in SKOV-3 cells, (3) pharmacological Src inhibitor PP2 or antisense (AS) c-Src oligodeoxynucleotide (ODN) treatment significantly induces TGF-,1-dependent activation of Smads, leading to PAI-1 synthesis, compared with controls, in SKOV-3 cells, (4) combination of TGF-,1 and PP2, which activates PAI-1 expression and reduces uPA expression in SKOV-3, results in decreased invasiveness, (5) pharmacological inhibitors for mitogen-activated protein kinase (MAPK) (PD98059) and phosphoinositide-3-kinase (PI3K) (LY294002 and wortmannin) or AS-PI3K ODN transfection do not affect TGF-,1-induced Smad signaling and up-regulation of PAI-1 expression in SKOV-3 cells pr treated with PP2, and (6) the induction of PAI-1 protein was partially inhibited by an inhibitor of Sp1-DNA binding, mithramycin, implicating, at least in part, Sp1 in the regulation of this gene by TGF-,1. In conclusion, TGF-,1-dependent activation of Smad2/3, leading to PAI-1 synthesis, may be negatively regulated by Src, but not its downstream targets MAPK and PI3K in SKOV-3 cells. These data also reflect the complex biological effect of uPA-PAI-1 system. © 2004 Wiley-Liss, Inc. [source] Src is a major signaling component for CTGF induction by TGF-,1 in osteoblasts,JOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2010X. Zhang Connective tissue growth factor (CTGF/CCN2) is induced by transforming growth factor ,1 (TGF-,1) where it acts as a downstream mediator of TGF-,1 induced matrix production in osteoblasts. We have shown the requirement of Src, Erk, and Smad signaling for CTGF induction by TGF-,1 in osteoblasts; however, the potential interaction among these signaling pathways remains undetermined. In this study we demonstrate that TGF-,1 activates Src kinase in ROS17/2.8 cells and that treatment with the Src family kinase inhibitor PP2 prevents Src activation and CTGF induction by TGF-,1. Additionally, inhibiting Src activation prevented Erk activation, Smads 2 and 3 activation and nuclear translocation by TGF-,1, demonstrating that Src is an essential upstream signaling partner of both Erk and Smads in osteoblasts. MAPKs such as Erk can modulate the Smad pathway directly by mediating the phosphorylation of Smads or indirectly through activation/inactivation of required nuclear co-activators that mediate Smad DNA binding. When we treated cells with the Erk inhibitor, PD98059, it inhibited TGF-,1-induced CTGF protein expression but had no effect on Src activation, Smad activation or Smad nuclear translocation. However PD98059 impaired transcriptional complex formation on the Smad binding element (SBE) of the CTGF promoter, demonstrating that Erk activation was required for SBE transactivation. These data demonstrate that Src is an essential upstream signaling transducer of Erk and Smad signaling with respect to TGF-,1 in osteoblasts and that Smads and Erk function independently but are both essential for forming a transcriptionally active complex on the CTGF promoter in osteoblasts. J. Cell. Physiol. 224: 691,701, 2010. © 2010 Wiley-Liss, Inc. [source] Atypical protein kinase C activity is required for extracellular matrix degradation and invasion by Src-transformed cellsJOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2009Elena M. Rodriguez Atypical protein kinase C (aPKC) isoforms have been shown to mediate Src-dependent signaling in response to growth factor stimulation. To determine if aPKC activity contributes to the transformed phenotype of cells expressing oncogenic Src, we have examined the activity and function of aPKCs in 3T3 cells expressing viral Src (v-Src). aPKC activity and tyrosine phosphorylation were found to be elevated in some but not all clones of mouse fibroblasts expressing v-Src. aPKC activity was inhibited either by addition of a membrane-permeable pseudosubstrate, by expression of a dominant-negative aPKC, or by RNAi-mediated knockdown of specific aPKC isoforms. aPKC activity contributes to morphological transformation and stress fiber disruption, and is required for migration of Src-transformed cells and for their ability to polarize at the edge of a monolayer. The , isoform of aPKC is specifically required for invasion through extracellular matrix in Boyden chamber assays and for degradation of the extracellular matrix in in situ zymography assays. Tyrosine phosphorylation of aPKC, is required for its ability to promote cell invasion. The defect in invasion upon aPKC inhibition appears to result from a defect in the assembly and/or function of podosomes, invasive adhesions on the ventral surface of the cell that are sites of protease secretion. aPKC was also found to localize to podosomes of v-Src transformed cells, suggesting a direct role for aPKC in podosome assembly and/or function. We conclude that basal or elevated aPKC activity is required for the ability of Src-transformed cells to degrade and invade the extracellular matrix. J. Cell. Physiol. 221: 171,182, 2009. © 2009 Wiley-Liss, Inc [source] | ||||||||||||||||||||||||||||||||||