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  • 1.
    Aifa, Sami
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Aydin, J
    Nordvall, G
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Svensson, Samuel
    Hermanson, O
    A basic peptide within the juxtamembrane region is required for EGF receptor dimerization2005In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 302, no 1, p. 108-114Article in journal (Refereed)
    Abstract [en]

    The epidermal growth factor receptor (EGFR) is fundamental for normal cell growth and organ development, but has also been implicated in various pathologies, notably tumors of epithelial origin. We have previously shown that the initial 13 amino acids (P13) within the intracellular juxtamembrane region (R645-R657) are involved in the interaction with calmodulin, thus indicating an important role for this region in EGFR function. Here we show that P13 is required for proper dimerization of the receptor. We expressed either the intracellular domain of EGFR (TKJM) or the intracellular domain lacking P13 (ΔTKJM) in COS-7 cells that express endogenous EGFR. Only TKJM was immunoprecipitated with an antibody directed against the extracellular part of EGFR, and only TKJM was tyrosine phosphorylated by endogenous EGFR. Using SK-N-MC cells, which do not express endogenous EGFR, that were stably transfected with either wild-type EGFR or recombinant full-length EGFR lacking P13 demonstrated that P13 is required for appropriate receptor dimerization. Furthermore, mutant EGFR lacking P13 failed to be autophosphorylated. P13 is rich in basic amino acids and in silico modeling of the EGFR in conjunction with our results suggests a novel role for the juxtamembrane domain (JM) of EGFR in mediating intracellular dimerization and thus receptor kinase activation and function. © 2004 Elsevier Inc. All rights reserved.

  • 2.
    Aspenström, Pontus
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    The mammalian verprolin homologue WIRE participates in receptor-mediated endocytosis and regulation of the actin filament system by distinct mechanisms2004In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 298, no 2, p. 485-498Article in journal (Refereed)
    Abstract [en]

    The mammalian verprolin family consists of three family members: WIP, WIRE and CR16. WIRE was recently found to bind to WASP and N-WASP and to have roles in regulating actin dynamics downstream of the platelet-derived growth factor beta-receptor. In the current study, the WASP-binding domain of WIRE was identified, with the core of the binding motif encompassing amino acid residues 408-412. A stretch of aromatic amino acid residues close to the core motif also participates in WASP binding. Amino acid substitutions in each of these motifs abrogated WASP binding, suggesting that both motifs are involved in the binding of WIRE to WASP. Interestingly, WIRE mutants unable to bind WASP were still able to induce a reorganisation of the actin filament system, indicating that WASP did not participate in the signalling pathway that link WIRE to actin dynamics. In cells ectopically expressing WIRE, the endocytosis of the platelet-derived growth factor beta-receptor was drastically reduced. However, in contrast to the effect on the actin filament system, the WIRE-induced ablation of the receptor endocytosis required an intact WASP-binding domain. Moreover, WIRE was more efficient than WIP in inhibiting the receptor endocytosis, implicating that these two mammalian verprolins have distinct roles in mammalian cells.

  • 3.
    Aspenström, Pontus
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    The WASP-binding protein WIRE has a role in the regulation of the actin filament system downstream of the platelet-derived growth factor receptor2002In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 279, no 1, p. 21-33Article in journal (Refereed)
    Abstract [en]

    Activation of growth factor receptors, such as platelet-derived growth factor (PDGF) receptors, has a major impact on the motile behavior of vertebrate cells. The WASP family of proteins has been recognized as important regulators of actin polymerization via the activation of the Arp2/3 complex. The activity of the WASP proteins has, in turn, been shown to be governed by a number of associated proteins, including the WASP interacting protein (WIP). This report presents a novel WIP-like protein, WIRE (for WIP-related). WIRE was shown to bind to the WH1 domain of WASP and N-WASP. WIRE was localized to actin filaments in transiently transfected PAE/PDGFRbeta cells, and in cells simultaneously expressing WIRE and WASP, WIRE relocalized WASP to actin filaments, a relocalization that required direct interaction between the two proteins. In addition, WIRE was able to bind the PDGF receptor substrate Nckbeta. PDGF treatment of cells ectopically expressing WIRE resulted in formation of peripheral protrusions composed of filopodia and lamellipodia-like structures. In cells expressing both WIRE and WASP, PDGF treatment induced a translocation of WASP to the cell margin, an effect that required the presence of WIRE. Taken together, the data presented indicate that WIRE has a role in the WASP-mediated organization of the actin cytoskeleton and that WIRE is a potential link between the activated PDGF receptor and the actin polymerization machinery.

  • 4.
    Aspenström, Pontus
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Richnau, Ninna
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Johansson, Ann-Sofi
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    The diaphanous-related formin DAAM1 collaborates with the Rho GTPases RhoA and Cdc42, CIP4 and Src in regulating cell morphogenesis and actin dynamics2006In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 312, no 12, p. 2180-2194Article in journal (Refereed)
    Abstract [en]

    Binding partners for the Cdc42 effector CIP4 were identified by the yeast two-hybrid system, as well as by testing potential CIP4-binding proteins in coimmunoprecipitation experiments. One of the CIP4-binding proteins, DAAM1, was characterised in more detail. DAAM1 is a ubiquitously expressed member of the mammalian diaphanous-related formins, which include proteins such as mDia1 and mDia2. DAAM1 was shown to bind to the SH3 domain of CIP4 in vivo. Ectopically expressed DAAM1 localised in dotted pattern at the dorsal side of transfected cells and the protein was accumulated in the proximity to the microtubule organising centre. Moreover, ectopic expression of DAAM1 induced a marked alteration of the cell morphology, seen as rounding up of the cells, the formation of branched protrusions as well as a reduction of stress-fibres in the transfected cells. Coimmunoprecipitation experiments demonstrated that DAAM1 bound to RhoA and Cdc42 in a GTP-dependent manner. Moreover, DAAM1 was found to interact and collaborate with the non-receptor tyrosine kinase Src in the formation of branched protrusions. Taken together, our data indicate that DAAM1 communicates with Rho GTPases, CIP4 and Src in the regulation of the signalling pathways that co-ordinate the dynamics of the actin filament system.

  • 5.
    Aspenström, Pontus
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Ruusala, Aino
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Pacholsky, Dirk
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Taking Rho GTPases to the next level: the cellular functions of atypical Rho GTPases2007In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 313, no 17, p. 3673-3679Article, review/survey (Refereed)
    Abstract [en]

    The Rho GTPases are influential regulators of signalling pathways that control vital cellular processes such as cytoskeletal dynamics, gene transcription, cell cycle progression and cell transformation. A vast majority of the studies involving Rho GTPases have been focused to the famous triad, Cdc42, Rac1 and RhoA, but this protein family actually harbours 20 members. Recently, the less known Rho GTPases have received increased attention. Many of the less studied Rho GTPases have structural, as well as, functional features which makes it pertinent to classify them as atypical Rho GTPases. This review article will focus on the critical aspects of the atypical Rho GTPases, RhoH, Wrch-1, Chp and RhoBTB. These proteins are involved in a broad spectre of biological processes, such as cytoskeletal dynamics, T-cell signalling and protein ubiquitinylation. We will also discuss the roles of atypical Rho GTPases as oncogenes or tumour suppressors, as well as their potential involvement in human diseases.

  • 6.
    Babakov, V.N.
    et al.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
    Petukhova, O.A.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
    Turoverova, L.V.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
    Kropacheva, I.V.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
    Tentler, D.G.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
    Bolshakova, A.V.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
    Podolskaya, E.P.
    Laboratory of Environmental and Biomedical Mass Spectrometry, Institute for Analytical Instrumentation, St. Petersburg, 198103, Russian Federation.
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Pinaev, G.P.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
    RelA/NF-?B transcription factor associates with a-actinin-42008In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 314, no 5, p. 1030-1038Article in journal (Refereed)
    Abstract [en]

    The NF-?B/RelA family of transcription factors regulates inducible transcription of a large number of genes in response to diverse stimuli. Little is known, however, about the location of NF-?B in the cytoplasm and the transport mechanism to the nucleus. We found that NF-?B is associated with the actin-binding protein a-actinin-4. NF-?B and a-actinin-4 co-localized along actin stress fibers and in membrane lamellae in A431 cells. After a 30-min stimulation with EGF or TNF-a, a-actinin-4 and p65 were found in the nucleus. Disruption of cytoskeleton by cytochalasin D prior to treatment with TNF-a led to increase of p65 nuclear translocation. Antibodies to p65 subunit of NF-?B co-immunoprecipitated a-actinin-4 from A431 cell lysates and nuclear extracts, but a-actinin-1 and ß-actin were not found in the precipitates. Affinity chromatography experiments displayed that p65 and p50 subunits of NF-?B can bind to matrix-bound chicken gizzard a-actinin. We suggest that the a-actinin-4 is important for the NF-?B nuclear translocation and its functions inside the nucleus. © 2007 Elsevier Inc. All rights reserved.

  • 7. Bauerschmidt, Christina
    et al.
    Woodcock, Michael
    Stevens, David L.
    Hill, Mark A.
    Rothkamm, Kai
    Helleday, Thomas
    Stockholm University, Faculty of Science, Department of Genetics, Microbiology and Toxicology.
    Cohesin phosphorylation and mobility of SMC1 at ionizing radiation-induced DNA double-strand breaks in human cells2011In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 317, no 3, p. 330-337Article in journal (Refereed)
    Abstract [en]

    Cohesin, a hetero-tetrameric complex of SMC1, SMC3, Rad21 and Scc3, associates with chromatin after mitosis and holds sister chromatids together following DNA replication. Following DNA damage, cohesin accumulates at and promotes the repair of DNA double-strand breaks. In addition, phosphorylation of the SMC1/3 subunits contributes to DNA damage-induced cell cycle checkpoint regulation. The aim of this study was to determine the regulation and consequences of SMC1/3 phosphorylation as part of the cohesin complex. We show here that the ATM-dependent phosphorylation of SMC1 and SMC3 is mediated by H2AX, 53BP1 and MDC1. Depletion of RAD21 abolishes these phosphorylations, indicating that only the fully assembled complex is phosphorylated. Comparison of wild type SMC1 and SMC1S966A in fluorescence recovery after photo-bleaching experiments shows that phosphorylation of SMC1 is required for an increased mobility after DNA damage in G2-phase cells, suggesting that ATM-dependent phosphorylation facilitates mobilization of the cohesin complex after DNA damage.

  • 8. Benedito, Rui
    et al.
    Hellström, Mats
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Cancer and Vascular Biology.
    Notch as a hub for signaling in angiogenesis2013In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 319, no 9, p. 1281-1288Article, review/survey (Refereed)
  • 9. Berglund, Erik
    et al.
    Akcakaya, Pinar
    Berglund, David
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Transplantation Surgery.
    Karlsson, Fredrik
    Vukojevic, Vladana
    Lee, Linkiat
    Bogdanovic, Darko
    Lui, Weng-Onn
    Larsson, Catharina
    Zedenius, Jan
    Frobom, Robin
    Branstrom, Robert
    Functional role of the Ca2+-activated Cl- channel DOG1/TMEM16A in gastrointestinal stromal tumor cells2014In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 326, no 2, p. 315-325Article in journal (Refereed)
    Abstract [en]

    DOG1, a Ca2+-activated Cl- channel (CaCC), was identified in 2004 to be robustly expressed in gastrointestinal stromal tumors (GIST). It was rapidly included as a tumor marker in routine diagnostics, but the functional role remained unknown. CaCCs are important regulators of normal physiological functions, but also implicated in tumorigenesis, cancer progression, metastasis, cell migration, apoptosis, proliferation and viability in several malignancies. We therefore investigated whether DOG1 plays a role in the three latter in GIST by utilizing in vitro cell model systems. Confocal microscopy identified different subcellular localizations of DOG1 in imatinib-sensitive and imatinib-resistant cells. Electrophysiological studies confirmed that DOG1-specific pharmacological agents possess potent activating and inhibiting properties. Proliferation assays showed small effects up to 72 h, and flow cytometric analysis of adherent cells with 7-AAD/Annexin V detected no pharmacological effects on viable GIST cells. However, inhibition of DOG1 conveyed pro-apoptotic effects among early apoptotic imatinib-resistant cells. In conclusion, DOG1 generates Cl- currents in GIST that can be regulated pharmacologically, with small effects on cell viability and proliferation in vitro. Inhibition of DOG1 might act pro-apoptotic on some early apoptotic GIST cell populations. Further studies are warranted to fully illuminate the function of DOG1 and its potential as therapeutic target.

  • 10. Berglund, Erik
    et al.
    Berglund, David
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Transplantation Surgery.
    Akcakaya, Pinar
    Ghaderi, Mehran
    Dare, Elisabetta
    Berggren, Per-Olof
    Kohler, Martin
    Aspinwall, Craig A.
    Lui, Weng-Onn
    Zedenius, Jan
    Larsson, Catharina
    Branstrom, Robert
    Evidence for Ca2+-regulated ATP release in gastrointestinal stromal tumors2013In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 319, no 8, p. 1229-1238Article in journal (Refereed)
    Abstract [en]

    Gastrointestinal stromal tumors (GISTs) are thought to originate from the electrically active pacemaker cells of the gastrointestinal tract. Despite the presence of synaptic-like vesicles and proteins involved in cell secretion it remains unclear whether GIST cells possess regulated release mechanisms. The GIST tumor cell line GIST882 was used as a model cell system, and stimulus-release coupling was investigated by confocal microscopy of cytoplasmic free Ca2+ concentration ([Ca(2+)1](i)), flow cytometry, and luminometric measurements of extracellular ATP. We demonstrate that GIST cells have an intact intracellular Ca2+-signaling pathway that regulates ATP release. Cell viability and cell membrane integrity was preserved, excluding ATP leakage due to cell death and suggesting active ATP release. The stimulus-secretion signal transduction is at least partly dependent on Ca2+ influx since exclusion of extracellular Ca2+ diminishes the ATP release. We conclude that measurements of ATP release in GISTs may be a useful tool for dissecting the signal transduction pathway, mapping exocytotic components, and possibly for the development and evaluation of drugs. Additionally, release of ATP from GISTs may have importance for tumor tissue homeostasis and immune surveillance escape.

  • 11.
    Bergström, J.Daniel
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Genetics and Pathology.
    Westermark, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Genetics and Pathology.
    Heldin, Nils-Erik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Genetics and Pathology.
    Epidermal growth factor receptor signaling activates Met in human anaplastic thyroid carcinoma cells2000In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 259, no 1, p. 293-299Article in journal (Refereed)
    Abstract [en]

    Overexpression of Met is a common finding in thyroid carcinomas. Recently, we reported on overexpression and ligand-independent constitutive activation of Met in anaplastic thyroid carcinoma cells. In the present study we have investigated a putative mechanism for this phenomenon. Cell lines with constitutively activated Met expressed both TGF-alpha mRNA and protein. Western blot analysis revealed expression of receptors for epidermal growth factor (EGFR) in all carcinoma cell lines; in tumor cells with elevated levels of TGF-alpha mRNA there was a constitutive tyrosine phosphorylation of the EGFRs. Preincubation of carcinoma cells with suramin decreased EGFR activation and downregulated Met expression as well as the ligand-independent phosphorylation of Met. Similar results were obtained with a EGFR tyrosine kinase inhibitor, AG 1478. The MEK inhibitor U0126 had an even more pronounced effect compared to AG 1478, indicating a Ras/MAPK-mediated signal in the regulation of Met expression and activation. Inhibition of EGFR signaling also decreased proliferation of the anaplastic thyroid carcinoma cells. Thus, aberrant activation of EGFRs may lead to an overexpression and activation of Met, which may be of importance for the malignant phenotype of anaplastic thyroid carcinomas.

  • 12.
    Berthold, Jessica
    et al.
    University of Cologne.
    Schenková, Kristína
    University of Cologne.
    Ramos, Sonia
    University of Cologne.
    Miura, Yoshie
    University of Nebraska.
    Furukawa, Manabu
    University of Nebraska.
    Aspenström, Pontus
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Rivero, Francisco
    University of Hull.
    Characterization of RhoBTB-dependent Cul3 ubiquitin ligase complexes--evidence for an autoregulatory mechanism2008In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 314, no 19, p. 3453-3465Article in journal (Refereed)
    Abstract [en]

    RhoBTB proteins are atypical members of the Rho family of small GTPases. Two of the three RhoBTB proteins, RhoBTB1 and RhoBTB2, have been proposed as tumor suppressors and might function as adaptors of Cul3-dependent ubiquitin ligase complexes. Using yeast two-hybrid analysis and co-immunoprecipitation we show that all three RhoBTB proteins interact with Cul3. The interaction requires the N-terminal region of Cul3 and the first BTB domain of RhoBTB. RhoBTB3, the only RhoBTB with a prenylation motif, associates with vesicles that are frequently found in the vicinity of microtubules, suggesting a participation in some aspects of vesicle trafficking. We also show that RhoBTB2 and RhoBTB3 are capable of homo and heterodimerizing through the BTB domain region. The GTPase domain, which does not bind GTP, is able to interact with the BTB domain region, thus preventing proteasomal degradation of RhoBTB. This fits into a model in which an intramolecular interaction maintains RhoBTB in an inactive state, preventing the formation or the functionality of Cul3-dependent complexes. We also report a significantly decreased expression of RHOBTB and CUL3 genes in kidney and breast tumor samples and a very good correlation in the expression changes between RHOBTB and CUL3 that suggests that these genes are subject to a common inactivation mechanism in tumors.

  • 13. Blom, M.
    et al.
    Reis, K.
    Nehru, V.
    Blom, Hans
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Gad, A. K. B.
    Aspenström, P.
    RhoD is a Golgi component with a role in anterograde protein transport from the ER to the plasma membrane2015In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 333, no 2, p. 208-219Article in journal (Refereed)
    Abstract [en]

    RhoD is a member of the Rho GTPase family and it coordinates actin dynamics and membrane trafficking. Activation of RhoD results in formation of filopodia, dissolution of stress fibers, and the subsequent formation of short actin bundles. In addition, RhoD localizes to early endosomes and recycling endosomes, and has a regulatory role in endosome trafficking. In this study, we report on a function of RhoD in the regulation of Golgi homeostasis. We show that manipulation of protein and activation levels of RhoD, as well as of its binding partner WHAMM, result in derailed localization of Golgi stacks. Moreover, vesicle trafficking from the endoplasmic reticulum to the plasma membrane via the Golgi apparatus measured by the VSV-G protein is severely hampered by manipulation of RhoD or WHAMM. In summary, our studies demonstrate a novel role for this member of the Rho GTPases in the regulation of Golgi function.

  • 14.
    Blom, Magdalena
    et al.
    Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet.
    Reis, Katarina
    Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet.
    Heldin, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Kreuger, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Aspenström, Pontus
    Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet.
    The atypical Rho GTPase RhoD is a regulator of actin cytoskeleton dynamics and directed cell migration2017In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 352, no 2, p. 255-264Article in journal (Refereed)
    Abstract [en]

    RhoD belongs to the Rho GTPases, a protein family responsible for the regulation and organization of the actin cytoskeleton, and, consequently, many cellular processes like cell migration, cell division and vesicle trafficking. Here, we demonstrate that the actin cytoskeleton is dynamically regulated by increased or decreased protein levels of RhoD. Ectopic expression of RhoD has previously been shown to give an intertwined weave of actin filaments. We show that this RhoD-dependent effect is detected in several cell types and results in a less dynamic actin filament system. In contrast, RhoD depletion leads to increased actin filament-containing structures, such as cortical actin, stress fibers and edge ruffles. Moreover, vital cellular functions such as cell migration and proliferation are defective when RhoD is silenced. Taken together, we present data suggesting that RhoD is an important component in the control of actin dynamics and directed cell migration.

  • 15. Borgenström, M
    et al.
    Tienhaara, A
    Spillmann, Dorothe
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Salmivirta, Markku
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Jalkanen, M
    Testosterone-induced growth of S115 mouse mammary tumor cells is dependent on heparan sulfate2001In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 264, no 2, p. 307-314Article in journal (Refereed)
    Abstract [en]

    The androgen-induced proliferation of S115 mouse mammary tumor cells has been suggested to involve autocrinic fibroblast growth factor signaling. Heparan sulfate proteoglycans are required for fibroblast growth factor signaling, presumably due to their ability to alter binding of fibroblast growth factors to their receptors. We have investigated the role of heparan sulfate proteoglycans in the testosterone-induced proliferation of S115 cells. We demonstrate that when the cells are treated with sodium chlorate, which inhibits the sulfation of endogenous heparan sulfate proteoglycans, cell growth becomes dependent on exogenous heparin. The shortest heparin oligosaccharides supporting cell growth were octasaccharides, whereas dodecasaccharides were almost as effective as native heparin. The N-, 2-O-, and 6-O-sulfate groups of heparin were all required for full testosterone response. Treatment of S115 cells with chlorate or testosterone did not alter the expression of fibroblast growth factor receptors 1 or 3, whereas the expression of fibroblast growth factor receptor 2 was down-regulated. We have previously shown that overexpression of syndecan-1 heparan sulfate proteoglycan renders S115 cells insensitive to testosterone and now demonstrate that this effect can be overcome by sodium chlorate treatment in combination with exogenous heparin. Our results suggest that heparin-like molecules are intimately involved in the androgen-mediated proliferation of S115 cells.

  • 16.
    Claesson-Welsh, Lena
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Cancer and Vascular Biology.
    Gerhardt, Holger
    Introduction to the ECR special angiogenesis issue2013In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 319, no 9, p. 1239-1239Article in journal (Other academic)
  • 17. Dijksterhuis, Jacomijn P.
    et al.
    Arthofer, Elisa
    Marinescu, Voichita D.
    Nelander, Sven
    Uhlen, Mathias
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Ponten, Frederik
    Mulder, Jan
    Schulte, Gunnar
    High levels of WNT-5A in human glioma correlate with increased presence of tumor-associated microglia/monocytes2015In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 339, no 2, p. 280-288Article in journal (Refereed)
    Abstract [en]

    Malignant gliomas are among the most severe types of cancer, and the most common primary brain tumors. Treatment options are limited and the prognosis is poor. WNT-5A, a member of the WNT family of lipoglycoproteins, plays a role in oncogenesis and tumor progression in various cancers, whereas the role of WNT-5A in glioma remains obscure. Based on the role of WNT-5A as an oncogene, its potential to regulate microglia cells and the glioma-promoting capacities of microglia cells, we hypothesize that WNT-5A has a role in regulation of immune functions in glioma. We investigated WNT-5A expression by in silico analysis of the cancer genome atlas (TCGA) transcript profiling of human glioblastoma samples and immunohistochemistry experiments of human glioma tissue microarrays (TMA). Our results reveal higher WNT-5A protein levels and mRNA expression in a subgroup of gliomas (WNT-5A(high)) compared to non-malignant control brain tissue. Furthermore, we show a significant correlation between WNT-5A in the tumor and presence of major histocompatibility complex Class II-positive microglia/monocytes. Our data pinpoint a positive correlation between WNT-5A and a proinflammatory signature in glioma. We identify increased presence of microglia/monocytes as an important aspect in the inflammatory transformation suggesting a novel role for WNT-5A in human glioma.

  • 18.
    Dijksterhuis, Jacomijn P.
    et al.
    Karolinska Inst, Sect Receptor Biol & Signaling, Deptartment Physiol & Pharmacol, S-17177 Stockholm, Sweden..
    Arthofer, Elisa
    Karolinska Inst, Sect Receptor Biol & Signaling, Deptartment Physiol & Pharmacol, S-17177 Stockholm, Sweden..
    Marinescu, Voichita D.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Nelander, Sven
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Neuro-Oncology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Uhlen, Mathias
    KTH Royal Inst Technol, Sci Life Lab, SE-17121 Stockholm, Sweden..
    Ponten, Frederik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Mulder, Jan
    Karolinska Inst, Dept Neurosci, Sci Life Lab, S-17177 Stockholm, Sweden..
    Schulte, Gunnar
    Karolinska Inst, Sect Receptor Biol & Signaling, Deptartment Physiol & Pharmacol, S-17177 Stockholm, Sweden.;Masaryk Univ, Fac Sci, Inst Expt Biol, CS-61137 Brno, Czech Republic..
    High levels of WNT-5A in human glioma correlate with increased presence of tumor-associated microglia/monocytes2015In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 339, no 2, p. 280-288Article in journal (Refereed)
    Abstract [en]

    Malignant gliomas are among the most severe types of cancer, and the most common primary brain tumors. Treatment options are limited and the prognosis is poor. WNT-5A, a member of the WNT family of lipoglycoproteins, plays a role in oncogenesis and tumor progression in various cancers, whereas the role of WNT-5A in glioma remains obscure. Based on the role of WNT-5A as an oncogene, its potential to regulate microglia cells and the glioma-promoting capacities of microglia cells, we hypothesize that WNT-5A has a role in regulation of immune functions in glioma. We investigated WNT-5A expression by in silico analysis of the cancer genome atlas (TCGA) transcript profiling of human glioblastoma samples and immunohistochemistry experiments of human glioma tissue microarrays (TMA). Our results reveal higher WNT-5A protein levels and mRNA expression in a subgroup of gliomas (WNT-5A(high)) compared to non-malignant control brain tissue. Furthermore, we show a significant correlation between WNT-5A in the tumor and presence of major histocompatibility complex Class II-positive microglia/monocytes. Our data pinpoint a positive correlation between WNT-5A and a proinflammatory signature in glioma. We identify increased presence of microglia/monocytes as an important aspect in the inflammatory transformation suggesting a novel role for WNT-5A in human glioma.

  • 19. Eichner, Annegret
    et al.
    Brock, Josef
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Souchelnytskyi, Serhiy
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Bone morphogenetic protein-7 (OP1) and transforming growth factor-beta1 modulate 1,25(OH)2-vitamin D3-induced differentiation of human osteoblasts2002In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 275, no 1, p. 132-142Article in journal (Refereed)
    Abstract [en]

    Bone morphogenetic proteins (BMPs) and transforming growth factor-beta (TGFbeta) are potent regulators of osteoblast differentiation and proliferation, processes that are crucial in bone remodeling. BMPs and TGFbeta act in concert with other local factors and hormones, among them 1,25(OH)2-vitamin D3 and insulin. Here we show that BMP7 inhibits 1,25(OH)2-vitamin D3-induced differentiation of human osteoblasts, whereas TGFbeta1 stimulates it, as assessed by assays for alkaline phosphatase (ALP) induction, matrix mineralization, and morphology changes. BMP7 or TGFbeta1 alone affects the differentiation of human osteoblasts. Similar results were obtained in assays for ALP induction using conditionally immortalized human osteoblasts (hFOB) and primary osteoblasts obtained from trabecular bone of the femoral head after hip replacement surgery. BMP7 stimulation led to a decrease of 1,25(OH)2-vitamin D3-induced binding of nuclear proteins to a vitamin D response element, as shown by electrophoretic mobility shift assay. Our results suggest that 1,25(OH)2-vitamin D3 modulates in opposite ways the effects of BMP7 and TGFbeta1 on osteoblast differentiation.

  • 20.
    Eriksson, Ida
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Experimental Pathology. Linköping University, Faculty of Health Sciences.
    Joosten, M.
    Linköping University, Department of Clinical and Experimental Medicine, Experimental Pathology. Linköping University, Faculty of Health Sciences.
    Roberg, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Oto-Rhiono-Laryngology and Head & Neck Surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Otorhinolaryngology in Linköping.
    Öllinger, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Experimental Pathology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pathology and Clinical Genetics.
    The histone deacetylase inhibitor trichostatin A reduces lysosomal pH and enhances cisplatin-induced apoptosis2013In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 319, no 1, p. 12-20Article in journal (Refereed)
    Abstract [en]

    High activity of histone deacetylases (HDACs) has been documented in several types of cancer and may be associated with survival advantage. In a head and neck squamous cell carcinoma cell line, cisplatin-induced apoptosis was augmented by pretreatment with the HDAC inhibitor trichostatin Apoptosis was accompanied by lysosomal membrane permeabilization (LMP), as shown by immunoblotting of the lysosomal marker protease cathepsin B in extracted cytosol and by immunofluorescence. Moreover, LAMP-2 (lysosomal associated membrane protein-2) was translocated from lysosomal membranes and found in a digitonin extractable fraction together with cytosolic proteins and pretreatment with trichostatin A potentiated the release. Overall, protein level of LAMP-2 was decreased during cell death and, interestingly, inhibition of cysteine cathepsins, by the pan-cysteine cathepsin inhibitor zFA-FMK, prevented loss of LAMP-2. The importance of LAMP-2 for lysosomal membrane stability, was confirmed by showing that LAMP-2 knockout MEFs (mouse embryonic fibroblasts) were more sensitive to cisplatin as compared to the corresponding wildtype cells. Trichostatin A reduced lysosomal pH from 4.46 to 4.25 and cell death was prevented when lysosomal pH was increased by NH4Cl, or when inhibiting the activity of lysosomal proteases. We conclude that trichostatin A enhances cisplatin induced cell death by decreasing lysosomal pH, which augments cathepsin activity resulting in reduced LAMP-2 level, and might promote LMP.

  • 21.
    Erlandsson, Anna
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Larsson, Jimmy
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Forsberg-Nilsson, Karin
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Stem cell factor is a chemoattractant and a survival factor for CNS stem cells2004In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 301, no 2, p. 201-210Article in journal (Refereed)
    Abstract [en]

    Migration of neural cells to their final positions is crucial for the correct formation of the central nervous system. Several extrinsic factors are known to be involved in the regulation of neural migration. We asked if stem cell factor (SCF), well known as a chemoattractant and survival factor in the hematopoietic lineage, could elicit similar responses in neural stem cells. For that purpose, a microchemotaxis assay was used to study the effect of SCF on migration of neural stem cells from the embryonic rat cortex. Our results show that SCF-induced chemotaxis and that specific antibodies to SCF or tyrosine kinase inhibitors abolished the migratory response. The SCF-receptor, Kit, was expressed in neural stem cells and in their differentiated progeny. We also show that SCF is a survival factor, but not a mitogen or a differentiation factor for neural stem cells. These data suggest a role for SCF in cell migration and survival in the developing cortex.

  • 22.
    Gallini, Radiosa
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Molecular tools. Karolinska Inst, Dept Med Biochem & Biophys, Stockholm, Sweden..
    Lindblom, Per
    Gothenburg Univ, Sahlgrenska Acad, Dept Med Biochem, Gothenburg, Sweden.;AstraZeneca R&D, Molndal, Sweden..
    Bondjers, Cecilia
    Gothenburg Univ, Sahlgrenska Acad, Dept Med Biochem, Gothenburg, Sweden.;Sahlgrens Univ Hosp, Gothenburg, Sweden..
    Betsholtz, Christer
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Vascular Biology. Karolinska Inst, Dept Med Biochem & Biophys, Stockholm, Sweden..
    Andrae, Johanna
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Vascular Biology.
    PDGF-A and PDGF-B induces cardiac fibrosis in transgenic mice2016In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 349, no 2, p. 282-290Article in journal (Refereed)
    Abstract [en]

    Platelet-derived growth factors (PDGFs) and their receptors (PDGFRs) contribute to normal heart development. Deficient or abnormal expression of Pdgf and Pdgfr genes have a negative impact on cardiac development and function. The cellular effects of PDGFs in the hearts of Pdgf/Pdgfr mutants and the pathogenesis of the resulting abnormalities are poorly understood, but different PDGF isoforms induce varying effects. Here, we generated three new transgenic mouse types which complete a set of studies, where all different PDGF ligands have been expressed under the same heart specific alpha-myosin heavy chain promoter. Transgenic expression of the natural isoforms of Pdgfa and Pdgfb resulted in isoform specific fibrotic reactions and cardiac hypertrophy. Pdgfa overexpression resulted in a severe fibrotic reaction with up to 8-fold increase in cardiac size, leading to lethal cardiac failure within a few weeks after birth. In contrast, Pdgfb overexpression led to focal fibrosis and moderate cardiac hypertrophy. As PDGF-A and PDGF-B have different affinity for the two PDGF receptors, we analyzed the expression of the receptors and the histology of the fibrotic hearts. Our data suggest that the stronger fibrotic effect generated by Pdgfa overexpression was mediated by Pdgfra in cardiac interstitial mesenchymal cells, i.e. the likely source of extracellular matrix depostion and fibrotic reaction. The apparent sensitivity of the heart to ectopic PDGFR alpha agonists supports a role for endogenous PDGFRa agonists in the pathogenesis of cardiac fibrosis.

  • 23.
    Garcia-Gonzalez, Claudia
    et al.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Morrison, Jamie Ian
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Cardiac regeneration in non-mammalian vertebrates2014In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 321, no 1, p. 58-63Article, review/survey (Refereed)
    Abstract [en]

    The heart is a robust organ, capable of pumping nutrients and transferring oxygen throughout the body via a network of capillaries, veins and arteries, for the entirety of a human's life. However, the fragility of mammalian hearts is also evident when it becomes damaged and parts of the organ fail to function. This is due to the fact that rather than replenishing the damaged areas with functional cellular mass, fibrotic scar tissue is the preferred replacement, resulting in an organ with functional deficiencies. Due to the mammalian hearts incapability to regenerate following damage and the ever-increasing number of people worldwide suffering from heart disease, tireless efforts are being made to discover ways of inducing a regenerative response in this most important organ. One such avenue of investigation involves studying our distantly related non-mammalian vertebrate cousins, which over the last decade has proved to us that cardiac regeneration is possible. This review will highlight these organisms and provide insights into some of the seminal discoveries made in the heart regeneration field using these amazing chordates.

  • 24.
    Grundström, Gunilla
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Mosher, D.F.
    Sakai, T.
    Rubin, Kristoffer
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Integrin αvβ3 mediates platelet-derived growth factor-BB-stimulated collagen gel contraction in cells expressing signaling deficient integrin α2β12003In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 291, no 2, p. 463-473Article in journal (Refereed)
    Abstract [en]

    The interplay between the collagen-binding integrin, α2β1, and platelet-derived growth factor (PDGF) receptors in the context of functional interactions with collagen was studied. We expressed either wild-type α2β1 (α2β1A) or α2β1 with a Y783/795F mutation in the cytoplasmic tail of the β1 subunit (α2β1Amut) in the β1-null fibroblastic cell line, GD25. GD25 cells lack endogenous expression of the α1 and α2 integrin subunits and do not adhere to collagen even after transfection with β1A. Cells expressing α2β1Amut contracted three-dimensional collagen lattices less efficiently than those expressing α2β1A. PDGF-BB significantly stimulated lattice contraction by GD25-α2β1Amut cells. Both cell types responded chemotactically to PDGF-BB. Focal adhesion kinase (FAK) and p130Cas were phosphorylated when GD25-α2β1A cells, but not GD25-α2β1Amut cells were seeded on collagen-coated dishes. Subsequent treatment with PDGF-BB further increased phosphorylation of FAK and p130Cas only in GD25-α2β1A cells. However, when cultured within collagen lattices, FAK and p130Cas phosphorylation were stimulated in both α2β1A- and α2β1Amut-expressing cells but further phosphorylation, in response to subsequent treatment with PDGF-BB, was seen only in GD25-α2β1A cells. We show that the stimulatory effects of PDGF-BB on collagen gel contraction and chemotaxis by GD25-α2β1Amut cells were mediated by the αvβ3 integrin. Phosphorylation of p130Cas, but not FAK, in GD25-α2β1Amut cells seeded in collagen lattices also depended on αvβ3. Our results show that PDGF-BB stimulation of fibroblast–collagen interactions is mediated by the αvβ3 integrin when β1 integrin function is impaired.

  • 25.
    Gullberg, Donald
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical and Physiological Chemistry.
    Tingström, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical and Physiological Chemistry.
    Thuresson, A C
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical and Physiological Chemistry.
    Olsson, L
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Zoology.
    Terracio, L
    Borg, T K
    Rubin, Kristofer
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Beta 1 integrin-mediated collagen gel contraction is stimulated by PDGF1990In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 186, no 2, p. 264-272Article in journal (Refereed)
  • 26.
    Gustafsson, Karin
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
    Heffner, Garrett
    Wenzel, Pamela L.
    Curran, Matthew
    Grawé, Jan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology.
    McKinney-Freeman, Shannon L.
    Daley, Georg Q.
    Welsh, Michael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
    The Src Homology 2 Protein Shb Promotes Cell Cycle Progression In Murine Hematopoietic Stem Cells By Regulation Of Focal Adhesion Kinase Activity2013In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 319, no 12, p. 1852-1864Article in journal (Refereed)
    Abstract [en]

    The widely expressed adaptor protein Shb has previously been reported to contribute to T cell function due to its association with the T cell receptor and furthermore, several of Shb's known interaction partners are established regulators of blood cell development and function. In addition, Shb deficient embryonic stem cells displayed reduced blood cell colony formation upon differentiation in vitro. The aim of the current study was therefore to explore hematopoietic stem and progenitor cell function in the Shb knockout mouse. Shbdeficient bone marrow contained reduced relative numbers of long-term hematopoietic stem cells (LT-HSCs) that exhibited lower proliferation rates. Despite this, Shb knockout LT-HSCs responded promptly by entering the cell cycle in response to genotoxic stress by 5-fluorouracil treatment. In competitive LT-HSC transplantations, Shb null cells initially engrafted as well as the wild-type cells but provided less myeloid expansion over time. Moreover, Shb knockout bone marrow cells exhibited elevated basal activities of focal adhesion kinase/Rac1/p21-activated kinase signaling and reduced responsiveness to Stem Cell Factor stimulation. Consequently, treatment with a focal adhesion kinase inhibitor increased Shb knockout LT-HSC proliferation. The altered signaling characteristics thus provide a plausible mechanistic explanation for the changes in LT-HSC proliferation since these signaling intermediates have all been shown to participate in LT-HSC cell cycle control. In summary, the loss of Shb dependent signaling in bone marrow cells, resulting in elevated focal adhesion kinase activity and reduced proliferative responses in LT-HSCs under steady state hematopoiesis, confers a disadvantage to the maintenance of LT-HSCs over time.

  • 27.
    Han, Shuangshuang
    et al.
    Departments of Endoscopy Center, The First Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
    Jiang, Xia
    Departments of General Surgery, The First Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
    Sun, Xiao-Feng
    Department of Oncology and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
    Zhang, Hong
    Örebro University, School of Medical Sciences.
    Li, Chao
    Departments of Endoscopy Center, The First Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
    Zhao, Zengren
    Departments of General Surgery, The First Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
    Yu, Weifang
    Departments of Endoscopy Center, The First Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
    Application value of CyTOF 2 mass cytometer technology at single-cell level in human gastric cancer cells2019In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, article id 111568Article in journal (Refereed)
    Abstract [en]

    Chemotherapy and radiotherapy are main adjuvant therapies for the treatment of gastric cancer, the treatment effects are individual difference, but the specific mechanism is unknown. CyTOF 2 mass cytometer (CyTOF) enables the detecting up to 135 parameters on single cell, the emergence of which is an opportunity for proteomics research. We first tried to apply CyTOF technique to gastric cancer cells. We verified applicability of CyTOF in gastric cancer cells, and analyzed the responses of seventeen proteins to chemoradiotherapy in human gastric cancer AGS cells. To analyze the high dimensional CyTOF data, we used two statistical and visualization tools including viSNE and Citrus. Two specific clusters were found which had differences in protein expression profiles. CyTOF technology is proved feasibility and value at single cell level of gastric cancer.

  • 28.
    He, Shu-Lan
    et al.
    Key Laboratory of Environment and Gene Related Diseases, Xi'an Jiaotong University, Ministry Education, Xi'an, China; Key Laboratory of Trace Elements and Endemic Diseases, Xi'an Jiaotong University, Ministry of Health, Xi'an, China.
    Tan, Wu-Hong
    Key Laboratory of Environment and Gene Related Diseases, Xi'an Jiaotong University, Ministry Education, Xi'an, China; Key Laboratory of Trace Elements and Endemic Diseases, Xi'an Jiaotong University, Ministry of Health, Xi'an, China.
    Zhang, Zeng-Tie
    Key Laboratory of Environment and Gene Related Diseases, Xi'an Jiaotong University, Ministry Education, Xi'an, China; Key Laboratory of Trace Elements and Endemic Diseases, Xi'an Jiaotong University, Ministry of Health, Xi'an, China.
    Zhang, Feng
    Key Laboratory of Environment and Gene Related Diseases, Xi'an Jiaotong University, Ministry Education, Xi'an, China; Key Laboratory of Trace Elements and Endemic Diseases, Xi'an Jiaotong University, Ministry of Health, Xi'an, China.
    Qu, Cheng-Juan
    Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland.
    Lei, Yan-Xia
    Key Laboratory of Environment and Gene Related Diseases, Xi'an Jiaotong University, Ministry Education, Xi'an, China; Key Laboratory of Trace Elements and Endemic Diseases, Xi'an Jiaotong University, Ministry of Health, Xi'an, China.
    Zhu, Yan-He
    Key Laboratory of Environment and Gene Related Diseases, Xi'an Jiaotong University, Ministry Education, Xi'an, China; Key Laboratory of Trace Elements and Endemic Diseases, Xi'an Jiaotong University, Ministry of Health, Xi'an, China.
    Yu, Han-Jie
    Department of Biotechnology, Northwest University, Xi'an, China.
    Xiang, You-Zhang
    Shandong Institute for prevention & Treatment of Endemic Disease, Jinan, China.
    Guo, Xiong
    Key Laboratory of Environment and Gene Related Diseases, Xi'an Jiaotong University, Ministry Education, Xi'an, China; Key Laboratory of Trace Elements and Endemic Diseases, Xi'an Jiaotong University, Ministry of Health, Xi'an, China.
    Mitochondrial-related gene expression profiles suggest an important role of PGC-1alpha in the compensatory mechanism of endemic dilated cardiomyopathy.2013In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 319, no 17, p. 2604-2616, article id 23954821Article in journal (Refereed)
    Abstract [en]

    Keshan disease (KD) is an endemic dilated cardiomyopathy with unclear etiology. In this study, we compared mitochondrial-related gene expression profiles of peripheral blood mononuclear cells (PBMCs) derived from 16 KD patients and 16 normal controls in KD areas. Total RNA was isolated, amplified, labeled and hybridized to Agilent human 4 × 44k whole genome microarrays. Mitochondrial-related genes were screened out by the Third-Generation Human Mitochondria-Focused cDNA Microarray (hMitChip3). Quantitative real-time PCR, immunohistochemical and biochemical parameters related mitochondrial metabolism were conducted to validate our microarray results. In KD samples, 34 up-regulated genes (ratios ≥ 2.0) were detected by significance analysis of microarrays and ingenuity systems pathway analysis (IPA). The highest ranked molecular and cellular functions of the differentially regulated genes were closely related to amino acid metabolism, free radical scavenging, carbohydrate metabolism, and energy production. Using IPA, 40 significant pathways and four significant networks, involved mainly in apoptosis, mitochondrion dysfunction, and nuclear receptor signaling were identified. Based on our results, we suggest that PGC-1alpha regulated energy metabolism and anti-apoptosis might play an important role in the compensatory mechanism of KD. Our results may lead to the identification of potential diagnostic biomarkers for KD in PBMCs, and may help to understand the pathogenesis of KD.

  • 29.
    Hedman, H
    et al.
    University of Umeå.
    Alenius, Mattias
    University of Umeå.
    Lundgren, E
    University of Umeå.
    Defective expression of beta 1-integrins in cells with constitutively active alpha L beta 2-integrins1997In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 232, no 2, p. 270-276Article in journal (Refereed)
    Abstract [en]

    We have investigated a potential relationship between expression of beta 1-integrins and adhesiveness of the beta 2-integrin LFA-1 (alpha L beta 2, CD11a/CD18). By an approach of random mutagenesis and selection we established clones from the human acute lymphatic leukemia cell line HPB-ALL with (i) constitutively active LFA-1 and (ii) with no apparent integrin-beta 1 cell surface expression. Thirty seven of 42 clones selected for activated LFA-1 were found to have lost apparent integrin-beta 1 expression. Conversely, 7 of 21 clones selected for lack of beta 1 expression were found to have activated LFA-1. Since this pointed toward a possible coupling between beta 1 expression and LFA-1 activity, we further analyzed at which level beta 1 expression was blocked. We focused on one clone, HAP4, with activated LFA-I and no detectable beta 1 cell surface expression and found, surprisingly, that it expressed wild-type levels of beta 1 mRNA and, in Western blots of whole cell lysates, apparently normal levels of beta 1 protein. However, in addition to beta 1 of the expected molecular weight, HAP4 expressed a unique 48-kDa band recognized by the polyclonal anti-beta 1 antiserum. Immunoprecipitation experiments revealed that the epitope recognized by the anti-beta 1 antibody 4B4 was hidden or lost. The alpha 4-chain was found in its precursor form but it did not associate with any beta-chain, and it was not processed to its mature form. Instead alpha 4-chains were eventually degraded. Taken together this showed that beta 1-chains were produced but not properly processed in HAP4. From this we propose that HAP4 is deficient in a gene product required both for proper beta 1 folding and for repression of LFA-1 adhesiveness.

  • 30.
    Hedman, H.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Alenius, Mattias
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Lundgren, E.
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Defective expression of beta 1-integrins in cells with constitutively active alpha L beta 2-integrins1997In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 232, no 2, p. 270-276Article in journal (Refereed)
    Abstract [en]

    We have investigated a potential relationship between expression of beta 1-integrins and adhesiveness of the beta 2-integrin LFA-1 (alpha L beta 2, CD11a/CD18). By an approach of random mutagenesis and selection we established clones from the human acute lymphatic leukemia cell line HPB-ALL with (i) constitutively active LFA-1 and (ii) with no apparent integrin-beta 1 cell surface expression. Thirty seven of 42 clones selected for activated LFA-1 were found to have lost apparent integrin-beta 1 expression. Conversely, 7 of 21 clones selected for lack of beta 1 expression were found to have activated LFA-1. Since this pointed toward a possible coupling between beta 1 expression and LFA-1 activity, we further analyzed at which level beta 1 expression was blocked. We focused on one clone, HAP4, with activated LFA-I and no detectable beta 1 cell surface expression and found, surprisingly, that it expressed wild-type levels of beta 1 mRNA and, in Western blots of whole cell lysates, apparently normal levels of beta 1 protein. However, in addition to beta 1 of the expected molecular weight, HAP4 expressed a unique 48-kDa band recognized by the polyclonal anti-beta 1 antiserum. Immunoprecipitation experiments revealed that the epitope recognized by the anti-beta 1 antibody 4B4 was hidden or lost. The alpha 4-chain was found in its precursor form but it did not associate with any beta-chain, and it was not processed to its mature form. Instead alpha 4-chains were eventually degraded. Taken together this showed that beta 1-chains were produced but not properly processed in HAP4. From this we propose that HAP4 is deficient in a gene product required both for proper beta 1 folding and for repression of LFA-1 adhesiveness.

  • 31.
    Heldin, Johan
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Rubin Sander, Marie
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Leino, Mattias
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Thomsson, Sara
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Söderberg, Ola
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Dynamin inhibitors impair platelet-derived growth factor beta-receptor dimerization and signaling2019In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 380, no 1, p. 69-79Article in journal (Refereed)
    Abstract [en]

    The role of plasma membrane composition and dynamics in the activation process of receptor tyrosine kinases (RTKs) is still poorly understood. In this study we have investigated how signaling via the RTK, platelet-derived growth factor beta-receptor (PDGFR-beta) is affected by Dynasore or Dyngo-4a, which are commonly used dynamin inhibitors. PDGFR-beta preferentially internalizes via clathrin-coated pits and in this pathway, Dynamin II has a major role in the formation and release of vesicles from the plasma membrane by performing the membrane scission. We have found that dynamin inhibitors impedes the activation of PDGFR-beta by impairing ligand-induced dimerization of the receptor monomers, which leads to a subsequent lack of phosphorylation and activation both of receptors and downstream effectors, such as ERK1/2 and AKT. In contrast, dynamin inhibitors did not affect epidermal growth factor receptor (EGFR) dimerization and phosphorylation. Our findings suggest that there is a link between plasma membrane dynamics and PDGFR-beta activation, and that this link is not shared with the epidermal growth factor receptor.

  • 32.
    Holmfeldt, Per
    et al.
    Umeå universitet, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Sellin, Mikael E.
    Umeå universitet, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Gullberg, Martin
    Umeå universitet, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Upregulated Op18/stathmin activity causes chromosomal instability through a mechanism that evades the spindle assembly checkpoint2010In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 316, no 12, p. 2017-2026Article in journal (Refereed)
    Abstract [en]

    Op18/stathmin (Op18) is a microtubule-destabilizing protein that is phosphorylation-inactivated during mitosis and its normal function is to govern tubulin subunit partitioning during interphase. Human tumors frequently overexpress Op18 and a tumor-associated Q18-->E mutation has been identified that confers hyperactivity, destabilizes spindle microtubules, and causes mitotic aberrancies, polyploidization, and chromosome loss in K562 leukemia cells. Here we determined whether wild-type and mutant Op18 have the potential to cause chromosomal instability by some means other than interference with spindle assembly, and thereby bypassing the spindle assembly checkpoint. Our approach was based on Op18 derivatives with distinct temporal order of activity during mitosis, conferred either by differential phosphorylation inactivation or by anaphase-specific degradation through fusion with the destruction box of cyclin B1. We present evidence that excessive Op18 activity generates chromosomal instability through interference occurring subsequent to the metaphase-to-anaphase transition, which reduces the fidelity of chromosome segregation to spindle poles during anaphase. Similar to uncorrected merotelic attachment, this mechanism evades detection by the spindle assembly checkpoint and thus provides an additional route to chromosomal instability.

  • 33.
    Holmfeldt, Per
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Sellin, Mikael E
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Gullberg, Martin
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Upregulated Op18/stathmin activity causes chromosomal instability through a mechanism that evades the spindle assembly checkpoint.2010In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 316, no 12, p. 2017-2026Article in journal (Refereed)
    Abstract [en]

    Op18/stathmin (Op18) is a microtubule-destabilizing protein that is phosphorylation-inactivated during mitosis and its normal function is to govern tubulin subunit partitioning during interphase. Human tumors frequently overexpress Op18 and a tumor-associated Q18-->E mutation has been identified that confers hyperactivity, destabilizes spindle microtubules, and causes mitotic aberrancies, polyploidization, and chromosome loss in K562 leukemia cells. Here we determined whether wild-type and mutant Op18 have the potential to cause chromosomal instability by some means other than interference with spindle assembly, and thereby bypassing the spindle assembly checkpoint. Our approach was based on Op18 derivatives with distinct temporal order of activity during mitosis, conferred either by differential phosphorylation inactivation or by anaphase-specific degradation through fusion with the destruction box of cyclin B1. We present evidence that excessive Op18 activity generates chromosomal instability through interference occurring subsequent to the metaphase-to-anaphase transition, which reduces the fidelity of chromosome segregation to spindle poles during anaphase. Similar to uncorrected merotelic attachment, this mechanism evades detection by the spindle assembly checkpoint and thus provides an additional route to chromosomal instability.

  • 34.
    Holmström, Therese E.
    et al.
    Stockholm University, Faculty of Science, The Wenner-Gren Institute .
    Mattsson, Charlotte L.
    Stockholm University, Faculty of Science, The Wenner-Gren Institute .
    Fälting, Johanna M.
    Nedergaard, Jan
    Stockholm University, Faculty of Science, The Wenner-Gren Institute .
    Differential signalling pathways for EGF versus PDGF activation of Erk1/2 MAP kinase and cell proliferation in brown pre-adipocytes2008In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 314, no 19, p. 3581-3592Article in journal (Refereed)
  • 35.
    Holmström, Therese E.
    et al.
    Stockholm University, Faculty of Science, The Wenner-Gren Institute.
    Mattsson, Charlotte L.
    Stockholm University, Faculty of Science, The Wenner-Gren Institute.
    Wang, Yanling
    Stockholm University, Faculty of Science, The Wenner-Gren Institute.
    Iakovleva, Irina
    Stockholm University, Faculty of Science, The Wenner-Gren Institute.
    Petrovic, Natasa
    Stockholm University, Faculty of Science, The Wenner-Gren Institute.
    Nedergaard, Jan
    Stockholm University, Faculty of Science, The Wenner-Gren Institute.
    Non-transactivational, dual pathways for LPA-induced Erk1/2 activation in primary cultures of brown pre-adipocytes2010In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 316, no 16, p. 2664-75Article in journal (Refereed)
    Abstract [en]

    In many cell types, G-protein-coupled receptor (GPCR)-induced Erk1/2 MAP kinase activation is mediated via receptor tyrosine kinase (RTK) transactivation, in particular via the epidermal growth factor (EGF) receptor. Lysophosphatidic acid (LPA), acting via GPCRs, is a mitogen and MAP kinase activator in many systems, and LPA can regulate adipocyte proliferation. The mechanism by which LPA activates the Erk1/2 MAP kinase is generally accepted to be via EGF receptor transactivation. In primary cultures of brown pre-adipocytes, EGF can induce Erk1/2 activation, which is obligatory and determinant for EGF-induced proliferation of these cells. Therefore, we have here examined whether LPA, via EGF transactivation, can activate Erk1/2 in brown pre-adipocytes. We found that LPA could induce Erk1/2 activation. However, the LPA-induced Erk1/2 activation was independent of transactivation of EGF receptors (or PDGF receptors) in these cells (whereas in transformed HIB-1B brown adipocytes, the LPA-induced Erk1/2 activation indeed proceeded via EGF receptor transactivation). In the brown pre-adipocytes, LPA instead induced Erk1/2 activation via two distinct non-transactivational pathways, one G(i)-protein dependent, involving PKC and Src activation, the other, a PTX-insensitive pathway, involving PI3K (but not Akt) activation. Earlier studies showing LPA-induced Erk1/2 activation being fully dependent on RTK transactivation have all been performed in cell lines and transfected cells. The present study implies that in non-transformed systems, RTK transactivation may not be involved in the mediation of GPCR-induced Erk1/2 MAP kinase activation

  • 36. Holmvall, K
    et al.
    Camper, L
    Johansson, Staffan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Kimura, J.H.
    Lundgren-Åkerlund, E
    Chondrocyte and chondrosarcoma cell integrins with affinity for collagen type II and their response to mechanical stress1995In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 221, no 2, p. 496-503Article in journal (Refereed)
    Abstract [en]

    Mechanical stress is an important regulator of chondrocyte functions but the mechanisms by which chondrocytes sense mechanical signals are unknown. Receptors for matrix molecules are likely involved in the mechanical signaling. In the first part of this study we identified integrins with affinity for the cartilage-specific collagen type II. We report that the collagen-binding integrins alpha 1 beta 1 and alpha 2 beta 1 isolated from bovine chondrocytes or human chondrosarcoma cells bound collagen type II as judged from affinity chromatography. The integrins alpha 3 beta 1 or alpha 9 beta 1 did not bind collagen type II-Sepharose. In the second part of the study we investigated the effect of mechanical stress on expression of matrix molecules and integrin subunits. Chondrocytes and chondrosarcoma cells, cultured on uncoated flexible silicone membranes in the presence of serum, were exposed to mechanical stress by the Flexercell system. Dynamic stimulation of chondrocytes for 3 h increased the mRNA expression of collagen type II and aggrecan as judged by Northern blotting, while the beta 1-integrin subunit was not changed. When chondrosarcoma cells were exposed to mechanical stimulation under the same conditions, mRNA expression of alpha 5 was found to increase while beta 1, alpha 2, and alpha v did not increase to significant levels. In another study the effect of mechanical stress on integrins was investigated when the cells were cultured on collagen type II-coated flex-dishes. Three hours of dynamic stress increased the mRNA expression of alpha 2-integrin subunit while the level of mRNA for integrin subunits beta 1, alpha 1, alpha 5, and alpha v showed no or small changes, indicating that matrix components may modulate the expression of integrins during mechanical stress.

  • 37.
    Hooshmand-Rad, Roya
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Lu, Lingge
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Claesson-Welsh, Lena
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Genetics and Pathology.
    Welsh, Michael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
    Platelet-Derived Growth Factor-Mediated Signaling through the Shb Adaptor Protein: Effects on Cytoskeletal Organization2000In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 257, no 2, p. 245-254Article in journal (Refereed)
    Abstract [en]

    The Src homology (SH) 2 domain adaptor protein Shb has previously been shown to interact with the platelet-derived growth factor (PDGF)-β receptor. In this study we show an association between Shb and the PDGF-α receptor which is mediated by the SH2 domain of Shb and involves tyrosine residue 720 in the kinase insert domain of the receptor. To assess the role of Shb in PDGF-mediated signaling, we have overexpressed wild-type Shb or Shb carrying a mutation (R522K) which renders the SH2 domain inactive, in Patch mouse (PhB) fibroblasts expressing both PDGF receptors (PhB/Rα). Overexpression of wild-type Shb, but not the R522K Shb mutant, affected PDGF-mediated reorganization of the cytoskeleton by decreasing membrane ruffle formation and stimulating the generation of filopodia relative the parental control cells. In addition, the PDGF-induced receptor-associated phosphatidylinositol 3′-kinase activity and phosphorylation of Akt was similar in both PhB/Rα/Shb and PhB/Rα/ShbR522K cells compared with the parental control, whereas the activation of Rac in response to PDGF-BB was diminished only in the PhB/Rα/Shb cells. We conclude that Shb plays a role in PDGF-dependent regulation of certain cytoskeletal changes by modulating the ability of PDGF to activate Rac.

  • 38.
    Hägerkvist, Robert
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
    Mokhtari, Dariush
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
    Lindholm, Cecilia
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
    Farnebo, Filip
    Mostoslavsky, Gustavo
    Mulligan, Richard C.
    Welsh, Nils
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
    Welsh, Michael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
    Consequences of Shb and c-Abl interactions for cell death in response to various stress stimuli2007In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 313, no 2, p. 284-291Article in journal (Refereed)
    Abstract [en]

    The adaptor protein Shb has previously been shown to regulate apoptosis in response to cytokines and inhibitors of angiogenesis although the mechanisms governing these effects have remained obscure. We currently demonstrate interactions between Shb and c-Abl and that Shb regulates c-Abl kinase activity. The data suggest that c-Abl binds to tyrosine phosphorylated Shb via a concerted effort involving both the c-Abl SH3 and SH2 domains. The biological significance of the Shb/c-Abl interaction was presently tested in overexpression experiments and was found to promote hydrogen peroxide-induced cell death. We also show by Shb knockdown experiments that Shb regulates c-Abl activity and modulates cell death in response to the genotoxic agent cisplatin and the endoplasmic reticulum stress-inducer tunicamycin. The findings are in agreement with the notion of Shb playing a pivotal role in modulating c-Abl pro-apoptotic signaling in response to various stress stimuli.

  • 39.
    Hägg, Maria
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Genetics and Pathology.
    Wennström, Stefan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Genetics and Pathology.
    Activation of hypoxia-induced transcription in normoxia2005In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 306, no 1, p. 180-191Article in journal (Refereed)
    Abstract [en]

    Hypoxia-inducible factor-1 (HIF-1), the master regulator of transcriptional responses to reduced oxygen tension (hypoxia) in mammalian cells, consists of one HIF-1alpha and one HIF-1beta subunit. In normoxia, HIF-1alpha subunits are hydroxylated on specific proline residues; modifications that signal ubiquitination and degradation of HIF-1alpha by the proteasome. To test the effect of saturating HIF-1alpha degradation, we generated a construct, denoted the saturating domain (SD), based on a region surrounding proline 564 (Pro564) in HIF-1alpha. Expression of the SD led to accumulation of endogenous HIF-1alpha proteins in nuclei of normoxic cells. The induced HIF-1alpha was functional as it activated expression from a hypoxia-regulated reporter gene and from the endogenous vascular endothelial growth facor-a (Vegf-a) and carbonic anhydrase 9 (Ca9) genes. The effect of the SD was dependent on Pro564 since a mutated SD, in which Pro564 had been replaced by a glycine residue, failed to bind the von Hippel-Lindau protein (pVHL) and to stabilise HIF-1alpha. Treatment of cells with the prolylhydroxylase inhibitor dimethyloxalylglycine, or the proteasome inhibitor MG-132, mimicked the effect of the SD. In conclusion, we show that blocking HIF-1alpha degradation, either by saturation, or inhibition of prolyl hydroxylases or proteosomal degradation, leads to nuclear localisation of active HIF-1alpha proteins.

  • 40. Iivanainen, Erika
    et al.
    Paatero, Ilkka
    Heikkinen, Satu-Maria
    Junttila, Teemu T.
    Cao, Renhai
    Klint, Peter
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Genetics and Pathology.
    Jaakkola, Panu M.
    Cao, Yihai
    Elenius, Klaus
    Intra- and extracellular signaling by endothelial neuregulin-12007In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 313, no 13, p. 2896-2909Article in journal (Refereed)
    Abstract [en]

    Suppression of tumor growth by inhibition of ErbB receptor signaling is well documented. However, relatively little is known about the ErbB signaling system in the regulation of angiogenesis, a process necessary for tumor growth. We have previously shown that heparin-binding EGF-like growth factor (HB-EGF) is expressed by vascular endothelial cells (EC) and promotes endothelial recruitment of vascular smooth muscle cells (SMC). To assess whether other members of the EGF-family regulate angiogenesis, the expression of 10 EGF-like growth factors in primary ECs and SMCs was analyzed. In addition to HB-EGF, neuregulin-1 (NRG-1) was expressed in ECs in vitro and in vivo. Endothelial NRG-1 was constitutively processed to soluble extracellular and intracellular signaling fragments, and its expression was induced by hypoxia. NRG-1 was angiogenic in vivo in mouse corneal pocket and chicken chorioallantoic membrane (CAM) assays. However, consistent with the lack of NRG-1 receptors in several primary EC lines, NRG-1 did not directly stimulate cellular responses in cultured ECs. In contrast, NRG-1 promoted EC responses in vitro and angiogenesis in CAM in vivo by mechanisms dependent on VEGF-A and VEGFR-2. These results indicate that NRG-1 is expressed by ECs and regulates angiogenesis by mechanisms involving paracrine up-regulation of VEGF-A.

  • 41.
    Imreh, Gabriela
    et al.
    Stockhlms univeristet.
    Beckman, M.
    Stockholms universitet.
    Iverfeldt, K.
    Stockholms universitet.
    Hallberg, Einar
    Stockholms universitet.
    Noninvasive monitoring of apoptosis versus necrosis in a neuroblastoma cell line expressing a nuclear pore protein tagged with the green fluorescent protein1998In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 238, no 2, p. 371-376Article in journal (Refereed)
    Abstract [en]

    A fusion chimera between the integral nuclear pore membrane protein POM121 and GFP (green fluorescent protein) has been shown to correctly target to the nuclear pores when transiently expressed in a number of mammalian cell types. POM121-GFP is therefore an excellent marker for the noninvasive studies of the nuclear pores in living cells using fluorescence microscopy. We have established a line of neuroblastoma cells stably expressing the POM121-GFP fusion protein. We also monitored the nuclear envelope in living cells after induction of apoptosis or necrosis using 1 μM staurosporine or 100 μM p-benzoquinone, respectively. Interestingly, the POM121-GFP fluorescence was weaker or missing in the apoptotic cells. The disappearance of the nuclear pore marker accompanied apoptotic progression as judged by the degree of chromatin condensation and DNA fragmentation as analyzed by DNA staining and TUNEL assay, respectively. In contrast, the intensity of the nuclear rim fluorescence was unaffected in necrotic cells displaying an abnormal morphology with tilted nuclei. Thus, it was possible to distinguish between apoptotic and necrotic development in living cells using fluorescence microscopy. This cell line provides a fast and convenient model for screening suspected toxic xenobiotics.

  • 42.
    Imreh, Gabriela
    et al.
    Södertörn University, Avdelning Naturvetenskap. Stockholm University.
    Hallberg, Einar
    Södertörn University, Avdelning Naturvetenskap.
    An integral membrane protein from the nuclear pore complex is also present in the annulate lamellae: Implications for annulate lamella formation2000In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 259, no 1, p. 180-190Article in journal (Refereed)
    Abstract [en]

    Annulate lamellae (AL) are cytoplasmic arrays of stacked membrane cisternae containing densely packed pore complexes which are similar in structure to the nuclear pore complexes (NPCs) and thus referred to as annulate lamella pore complexes (ALPCs). We have recently shown that the integral nuclear pore membrane protein POM121 tagged with green fluorescent protein was correctly targeted to the nuclear pores (H. Soderqvist et al., 1997, fur. J. Biochem. 250, 808-813). Here we have investigated if POM121 fused to three tandem molecules of yellow fluorescent protein YFP) (POM121-YFP3,) also was able to distribute in the extensive and well-characterized Al; of RC37 and BMGE cells. Transfected RC37 or BMGE cells displayed YFP fluorescence around the nuclear envelope, as well. as in the cytoplasmic AL structures. The YFP fluorescence colocalized perfectly with immunostaining using antibodies specific for different NPC proteins. The AL of both transfected and untransfected BMGE cells resisted extractions with Tx-100 and 250 mM NaCl, but were completely solubilized at 450 mM NaCl. Loss of YFP fluorescence and immunostaining for other NPC proteins correlated under all extraction conditions tested, suggesting that overexpressed POM121-YFP3, had become an integrated part both of the NPCs and of the ALPCs. Furthermore, we have generated a stable BHK cell line expressing POM121YFP(3,) located exclusively at the nuclear pores. Treatment with vinblastine sulfate, which induces formation of Al; in a variety of cells, resulted in distribution of POM121-YFP3, into cytoplasmic foci colocalizing with immunostaining for peripheral NPC proteins. Taken together, the results show that YFP-tagged POM121 is able to distribute in drug-induced or naturally occurring AL, suggesting that POM121 is a natural constituent of ALPCs. In COS cells, which normally lack or have very little AT-I, YFP-tagged POM121 distributed in the nuclear pores when expressed at low levels. However, at high expression levels the YFP fluorescence also distributed in a number of brightly fluorescing cytoplasmic dots or foci, which were not present in untransfected cells. This was also true for untagged POM121. The cytoplasmic foci varied in size from 0.1 to 2 mu m and were distinctly located in the immediate vicinity of ER cisternae (without colocalizing) and also contained other nuclear pore proteins, indicating that they may represent cytoplasmic AL. This idea is supported by time-lapse studies of postmitotic assembly of these structures. This raises the question of the role of POM121 in ALPC and NPC biogenesis.

  • 43.
    Imreh, Gabriela
    et al.
    Södertörn University, Avdelning Naturvetenskap. Stockholm University.
    Maksel, Danuta
    Södertörn University, Avdelning Naturvetenskap.
    de Monvel, J B
    Branden, L
    Hallberg, Einar
    Södertörn University, Avdelning Naturvetenskap.
    ER retention may play a role in sorting of the nuclear pore membrane protein POM1212003In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 284, no 2, p. 173-184Article in journal (Refereed)
    Abstract [en]

    Integral membrane proteins of the nuclear envelope (NE) are synthesized on the rough endoplasmic reticulum (ER) and following free diffusion in the continuous ER/NE membrane system are targeted to their proper destinations due to interactions of specific domains with other components of the NE. By studying the intracellular distribution and dynamics of a deletion mutant of an integral membrane protein of the nuclear pores, POM121, which lacks the pore-targeting domain, we investigated if ER retention plays a role in sorting of integral membrane proteins to the nuclear envelope. A nascent membrane protein lacking sorting determinants is believed to diffuse laterally in the continuous ER/NE lipid bilayer and expected to follow vesicular traffic to the plasma membrane. The GFP-tagged deletion mutant, POM121(1-129)-GFP, specifically distributed within the ER membrane, but was completely absent from the Golgi compartment and the plasma membrane. Experiments using fluorescence recovery after photobleaching (FRAP) and fluorescence loss in photobleaching (FLIP) demonstrated that despite having very high mobility within the whole ER network (D = 0.41 +/- 0.11 mum(2)/s) POM121(1-129)-GFP was unable to exit the ER. It was also not detected in post-ER compartments of cells incubated at 15degreesC. Taken together, these experiments show that amino acids 1-129 of POM121 are able to retain GFP in the ER membrane and suggest that this retention occurs by a direct mechanism rather than by a retrieval mechanism. Our data suggest that ER retention might be important for sorting of POM121 to the nuclear pores.

  • 44.
    Johansson, Karin C
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Comparative Physiology.
    Metzendorf, Christoph
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Comparative Physiology.
    Söderhäll, Kenneth
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Comparative Physiology.
    Microarray analysis of immune challenged Drosophila hemocytes2005In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 305, no 1, p. 145-155Article in journal (Refereed)
    Abstract [en]

    nsect hemocytes play multiple roles in immunity and carry out cellular responses like phagocytosis, encapsulation and melanization as well as producing humoral effector proteins in the first line of defense after injury and invasion of microorganisms. In this work, we used the Drosophila melanogaster hemocyte-like cell line mbn-2 and Affymetrix Drosophila GeneChips to investigate the transcriptome of a single type of immune competent tissue exposed to Gram-negative cell wall components (crude LPS) or high dose infection with live Escherichia coli. We found that gene expression profiles of both treatments overlap but show important differences in expression levels of several genes involved in immunity. In addition, cell morphology during infection was monitored and revealed distinct alterations in cell shape and adhesion. Presence of large numbers of bacteria also increased the number of cells taking on crystal cell fate. Taken together, our results indicate that hemocytes sense and respond differently to purified bacterial surface molecules and infection with live and actively growing bacteria both at the level of gene expression and in cell behavior.

  • 45.
    Johnsson, Anna-Karin
    et al.
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Cell Biology.
    Karlsson, Roger
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Cell Biology.
    Synaptotagmin 1 causes phosphatidyl inositol lipid-dependent actin remodeling in cultured non-neuronal and neuronal cells2012In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 318, no 2, p. 114-126Article in journal (Refereed)
    Abstract [en]

    Here we demonstrate that a dramatic actin polymerizing activity caused by ectopic expression of the synaptic vesicle protein synaptotagmin 1 that results in extensive filopodia formation is due to the presence of a lysine rich sequence motif immediately at the cytoplasmic side of the transmembrane domain of the protein. This polybasic sequence interacts with anionic phospholipids in vitro, and, consequently, the actin remodeling caused by this sequence is interfered with by expression of a phosphatidyl inositol (4,5)-bisphosphate (PIP2)-targeted phosphatase, suggesting that it intervenes with the function of PIP2-binding actin control proteins. The activity drastically alters the behavior of a range of cultured cells including the neuroblastoma cell line SH-SY5Y and primary cortical mouse neurons, and, since the sequence is conserved also in synaptotagmin 2, it may reflect an important fine-tuning role for these two proteins during synaptic vesicle fusion and neurotransmitter release.

  • 46.
    Karlsson, Henning
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine.
    Fryknäs, Mårten
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine.
    Larsson, Rolf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine.
    Nygren, Peter
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Loss of cancer drug activity in colon cancer HCT-116 cells during spheroid formation in a new 3-D spheroid cell culture system2012In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 318, no 13, p. 1577-1585Article in journal (Refereed)
    Abstract [en]

    Clinically relevant in vitro methods are needed to identify new cancer drugs for solid tumors. We report on a new 3-D spheroid cell culture system aimed to mimic the properties of solid tumors in vivo. The colon cancer cell lines HCT-116 wt and HCT-116 wt/GFP were grown as monolayers and for 3 or 6 days on 96-well NanoCulture (R) plates to form spheroids. Expression of surface markers, genes and hypoxia were assessed to characterize the spheroids and drug induced cytotoxicity was evaluated based on fluorescein diacetate (FDA) conversion by viable cells to fluorescent fluorescein or by direct measurement of fluorescence of GFP marked cells after a 72 h drug incubation. The cells reproducibly formed spheroids in the NanoCulture (R) plates with tight cell-attachment after 6 days. Cells in spheroids showed geno- and phenotypical properties reminiscent of hypoxic stem cells. Monolayer cultured cells were sensitive to standard and investigational drugs, whereas the spheroids gradually turned resistant. Similar results for cytotoxicity were observed using simplified direct measurement of fluorescence of GFP marked cells compared with FDA incubation. In conclusion, this new 3-D spheroid cell culture system provides a convenient and clinically relevant model for the identification and characterization of cancer drugs for solid tumors.

  • 47.
    Karlsson, Torbjörn
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
    Welsh, Michael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
    Modulation of Src homology 3 proteins by the proline-rich adaptor protein Shb1997In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 231, no 2, p. 269-275Article in journal (Refereed)
    Abstract [en]

    In the present study we have investigated a possible role for the proline-rich SH2 domain protein Shb as a regulator of expression or activity of certain SH3 domain proteins and MAP kinase. The expression of the Shb binding proteins Eps8, Src, and p85 PI3-kinase, PI3-kinase activity, and MAP kinase activation were assessed in wild-type NIH3T3 cells and in NIH3T3 cells overexpressing the Shb cDNA. In addition, the expression of the SH3 domain STAT1 proteins was assessed in wild-type and Shb overexpressing cells. The Eps8 protein content and Eps8 mRNA steady-state levels were downregulated, whereas the protein contents of Src and p85 PI3-kinase were unaffected by Shb overexpression. There was, however, an increased basal PI3-kinase activity in Shb transfected cells after a 3-h serum starvation. Increased steady-state levels of STAT1 mRNA were accompanied by an increased STAT1 protein content in Shb overexpressing cells. Shb overexpression was not associated with an altered activation of p44 or p42 MAP kinases in response to PDGF stimulation. The data presented in this study suggest novel functions for the adaptor protein Shb regulating the expression of certain signal-transducing SH3 domain proteins and modulating PI3-kinase activity.

  • 48. Karpanen, Terhi
    et al.
    Mäkinen, Taija
    Regulation of lymphangiogenesis--from cell fate determination to vessel remodeling.2006In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 312, no 5Article in journal (Refereed)
    Abstract [en]

    Lymphatic vessels are important for the maintenance of normal tissue fluid balance, immune surveillance and adsorption of digested fats. During the past decade, the identification of lymphatic-specific markers and growth factors has enabled detailed studies of the lymphatic system, and gain- and loss-of-function experiments have greatly increased our understanding of the mechanisms of normal lymphatic development. Understanding the basic biology has provided novel insights into the pathologic conditions of the lymphatic system that contribute to lymphedema, inflammation or lymphatic metastasis, and opened possibilities for the development of better therapeutic strategies. Here we review the current knowledge about the molecular mechanisms regulating the development of the lymphatic vasculature; of the differentiation of lymphatic endothelial cells, of the regulation of the growth of lymphatic vessels, and of remodeling of the vasculature into a network consisting of lymphatic capillaries and collecting lymphatic vessels. Furthermore, we will discuss the molecular mechanisms involved in the pathological conditions of the lymphatic vessels.

  • 49.
    Kihlmark, Madeleine
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Stockholm University.
    Rustum, Cecilia
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Stockholm University.
    Eriksson, Charlotta
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Beckman, M
    Stockholm University.
    Iverfeldt, K
    Stockholm University.
    Hallberg, Einar
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science.
    Correlation between nucleocytoplasmic transport and caspase-3-dependent dismantling of nuclear pores during apoptosis2004In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 293, no 2, p. 346-356Article in journal (Refereed)
    Abstract [en]

    During apoptosis (also called programmed cell death), the chromatin condenses and the DNA is cleaved into oligonucleosomal fragments. Caspases are believed to play a major role in nuclear apoptosis. However, the relation between dismantling of nuclear pores, disruption of the nucleocytoplasmic barrier, and nuclear entry of caspases is unclear. We have analyzed nuclear import of the green fluorescent protein fused to a nuclear localization signal (GFP-NLS) in tissue culture cells undergoing apoptosis. Decreased nuclear accumulation of GFP-NLS could be detected at the onset of nuclear apoptosis manifested as dramatic condensation and redistribution of chromatin toward the nuclear periphery. At this step, dismantling of nuclear pores was already evident as indicated by proteolysis of the nuclear pore membrane protein POM121. Thus, disruption of nuclear compartmentalization correlated with early signs of nuclear pore damage. Both these events clearly preceded massive DNA fragmentation, detected by TUNEL assay. Furthermore, we show that in apoptotic cells, POM121 is specifically cleaved at aspartate-531 in its large C-terminal portion by a caspase-3-dependent mechanism. Cleavage of the C-terminal portion of POM121, which is adjoining the nuclear pore complex, is likely to disrupt interactions with other nuclear pore proteins affecting the stability of the pore complex. A temporal correlation of apoptotic events supports a model where caspase-dependent disassembly of nuclear pores and disruption of the nucleocytoplasmic barrier paves the way for nuclear entry of caspases and subsequent activation of CAD-mediated DNA fragmentation.

  • 50.
    Kihlmark, Madeleine
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. Södertörn University College, Sweden.
    Rustum, Cecilia
    Stockholm University, Faculty of Science, Department of Neurochemistry and Neurotoxicology. Södertörn University College, Sweden.
    Eriksson, Charlotta
    Beckman, Marie
    Stockholm University, Faculty of Science, Department of Neurochemistry and Neurotoxicology.
    Iverfeldt, Kerstin
    Stockholm University, Faculty of Science, Department of Neurochemistry and Neurotoxicology.
    Hallberg, Einar
    Correlation between nucleocytoplasmic transport and caspase–3-dependent dismantling of nuclear pores during apoptosis2004In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 293, no 2, p. 346-356Article in journal (Refereed)
    Abstract [en]

    During apoptosis (also called programmed cell death), the chromatin condenses and the DNA is cleaved into oligonucleosomal fragments. Caspases are believed to play a major role in nuclear apoptosis. However, the relation between dismantling of nuclear pores, disruption of the nucleocytoplasmic barrier, and nuclear entry of caspases is unclear. We have analyzed nuclear import of the green fluorescent protein fused to a nuclear localization signal (GFP-NLS) in tissue culture cells undergoing apoptosis. Decreased nuclear accumulation of GFP-NLS could be detected at the onset of nuclear apoptosis manifested as dramatic condensation and redistribution of chromatin toward the nuclear periphery. At this step, dismantling of nuclear pores was already evident as indicated by proteolysis of the nuclear pore membrane protein POM121. Thus, disruption of nuclear compartmentalization correlated with early signs of nuclear pore damage. Both these events clearly preceded massive DNA fragmentation, detected by TUNEL assay. Furthermore, we show that in apoptotic cells, POM121 is specifically cleaved at aspartate-531 in its large C-terminal portion by a caspase-3-dependent mechanism. Cleavage of the C-terminal portion of POM121, which is adjoining the nuclear pore complex, is likely to disrupt interactions with other nuclear pore proteins affecting the stability of the pore complex. A temporal correlation of apoptotic events supports a model where caspase-dependent disassembly of nuclear pores and disruption of the nucleocytoplasmic barrier paves the way for nuclear entry of caspases and subsequent activation of CAD-mediated DNA fragmentation.

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